Researchers take step toward using cellular motion to help wound healing
With a technique that overcomes cells' innate social behaviors, researchers have taken an important step in directing skin cells to migrate en masse to close wounds—"literally making skin crawl".
In a new study, the researchers overcame the inertia typical of mature skin tissue by breaking the molecular connections between cells, applying an electrical field to direct their migration and then rebuilding the connections. This novel approach improves the controllability of tissues and may one day help optimize wound healing through electrical stimulation.
Research showed that cells in the body can sense and follow an electric field, a process called electrotaxis. Electric fields generated in the body promote healing by directing cells to move toward the wound and are also vital for growth and development.
Despite promising clinical evidence from decades of use in patients, scientists have yet to work out how cells detect and respond to electric fields or how electrical stimulation can best be applied therapeutically. "It's kind of a black box
Gawoon Shim et al, Overriding native cell coordination enhances external programming of collective cell migration, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2101352118
In their previous work, Cohen's group used electric fields to program thousands of individual cells to move in circles and around corners. Their new study used a model of more mature skin—a single layer of mouse skin cells all latched together—which is harder to control. Instead of moving with the speed and precision of a marching band in response to an electric current, the mature skin cells inched along like a crowd of people holding hands with their neighbors.
The mature skin also posed another problem: Once the leading edge of cells advanced, it would peel away from the petri dish and die. "If you apply a command that differs from what the cells naturally 'want' to do, you get a tug-of-war. The result was the tissues ripped themselves apart.
Cohen and Shim suspected that the "handshakes" between cells prevented the tissue from fluidly following the electrical commands. These handshakes are proteins called cadherins that anchor neighboring cells together. They make tissues cohesive so they can move together but can also create traffic jams when cells don't have space to move.
Gawoon Shim et al, Overriding native cell coordination enhances external programming of collective cell migration, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2101352118
Cadherins need calcium ions to complete their connections, so Shim grew the cells with different amounts of calcium and measured their response to electrical stimulation. She saw that the less calcium the cells had, the more fluid they became and the quicker they moved. "It goes really fast.
Calcium has many effects on living tissues, however, so Shim had to confirm that the handshakes were to blame for the slow movement. She grew cells with an antibody that attaches to cadherins. With blocked handshakes, these cells moved more quickly.
After working out the ground rules of cell adhesiveness, the researchers developed a solution to their sticky cell problem. Shim grew a layer of skin cells in a high calcium solution so they made their normal connections. Then she treated the cells with a chemical that grabs up calcium ions to break up the cellular handshakes. When Shim lowered the calcium level and applied the electric field, the cells moved on command. Finally, she restored the high calcium level to reinstate the handshakes, resulting in a healthy and cohesive layer ofskin cells.
To demonstrate that this approach has the potential to accelerate healing, Shim performed the above experiment using an electrobioreactor developed in the Cohen lab that mimics the closing of a wound. Unlike other models of electrotaxis where the electric field moves cells in one direction, their new system exposes cells to anelectric fieldfocused on the center of the injury. Shim showed that the stimulated tissues successfully came together while the unstimulated ones remained largely separate. Cohen's group described their electrobioreactor in anew paperinBiosensors and Bioelectronics.
Model of SARS-CoV-2 dynamics reveals opportunity to prevent COVID-19 transmission
Scientists have simulated the transition of the SARS-CoV-2 spike protein structure from when it recognizes the host cell to when it gains entry, according to a study published today ineLife.
The research shows that a structure enabled by sugar molecules on the spike protein could be essential for cell entry and that disrupting this structure could be a strategy to halt virus transmission. An essential aspect of SARS-CoV-2's lifecycle is its ability to attach to host cells and transfer its genetic material. It achieves this through its spike protein, which is made up of three separate components—a transmembrane bundle that anchors the spike to the virus, and two S subunits (S1 and S2) on the exterior of the virus. To infect a human cell, the S1 subunit binds to a molecule on the surface of human cells called ACE2, and the S2 subunit detaches and fuses the viral and human cell membranes. Although this process is known, the exact order in which it occurs is as yet undiscovered. Yet, understanding the microsecond-scale and atomic-level movements of these protein structures could reveal potential targets for COVID-19 treatment. Most of the current SARS-CoV-2 treatments and vaccines have focused on the ACE2 recognition step of virus invasion, but an alternative strategy is to target the structural change that allows the virus to fuse with the human host cell. But probing these intermediate, transient structures experimentally is extremely difficult, and so researchers now used a computer simulation sufficiently simplified to investigate this large system but that maintains sufficient physical details to capture the dynamics of the S2 subunit as it transitions between pre-fusion and post-fusion shapes. part 1
The team was particularly interested in the role of sugar molecules on the spike protein, which are called glycans. To see whether the number, type and position of glycans play a role in the membrane fusion stage of viral cell entry by mediating these intermediate spike formations, they performed thousands of simulations using an all-atom structure-based model. Such models allow prediction of the trajectory of atoms over time, taking into account steric forces—that is, how neighboring atoms affect the movement of others.
The simulations revealed that glycans form a "cage" that traps the "head" of the S2 subunit, causing it to pause in an intermediate form between when it detaches from the S1 subunit and when the viral and cell membranes are fused. When the glycans were not there, the S2 subunit spent much less time in this conformation.
The simulations also suggest that holding the S2 head in a particular position helps the S2 subunit recruit human hostcellsand fuse with their membranes, by allowing the extension of short proteins called fusion peptides from the virus. Indeed, glycosylation of S2 significantly increased the likelihood that a fusion peptide would extend to the host cell membrane, whereas when glycans were absent, there was only a marginal possibility that this would occur.
simulations indicate that glycans can induce a pause during the spike protein transition. This provides a critical opportunity for the fusion peptides to capture the host cell.
In the absence of glycans, the viral particle would likely fail to enter the host. Our study reveals how sugars can control infectivity, and it provides a foundation for experimentally investigating factors that influence the dynamics of this pervasive and deadly pathogen.
Esteban Dodero-Rojas et al, Sterically confined rearrangements of SARS-CoV-2 Spike protein control cell invasion, eLife (2021). DOI: 10.7554/eLife.70362
Scientists discover a rare, aggressive form of Alzheimer's that begins in the early 40s
A newly discovered gene mutation linked to early onset Alzheimer's disease has been discovered by an international team of scientists, who traced the DNA flaw through multiple members of a single family.
Alzheimer's has long been known as a mind-robbing disease that that wipes out memories and destroys one's sense of self. Most cases of arise sporadically, emerging after age of 65—transmuting one's golden years into a nightmare marked by an incurable brain disease.
Aside from Alzheimer's dementia that begins sporadically in old age, are insidious familial forms that begin years to decades earlier. Early onset refers Alzheimer's that begins before age 65.
Now, an international team of scientists—led by neurobiologists in Sweden—have identified an extraordinarily rare form of the disease that so far has been found only in one family. This form of Alzheimer's is aggressive, rapid and steals its victims' most productive years along their cognitive functions.
Researchers in Sweden have named this form of Alzheimer's—the Uppsala APP deletion—after the family that's endowed with this notorious DNA miscue. It invariably causes descent into dementia at a young age.
Affected individuals have an age at symptom onset in their early forties, and suffer from a rapidly progressing disease course.
Researchers found that the mutation accelerates the formation of brain-damaging protein plaques, known as amyloid beta, or more simply as Aβ. The gooey plaques destroy neurons and, as a result, annihilate the executive functions of the brain itself. Neuroscientists basically define executive functions as working memory, mental flexibility and self control.
María Pagnon de la Vega et al, The Uppsala APP deletion causes early onset autosomal dominant Alzheimer's disease by altering APP processing and increasing amyloid β fibril formation, Science Translational Medicine (2021). DOI: 10.1126/scitranslmed.abc6184
Do genetics control who our friends are? It seems so with mice
Have you ever met someone you instantly liked, or at other times, someone who you knew immediately that you did not want to be friends with, although you did not know why?
Some people speculated that "unconscious" part of the brain enables us to process information spontaneously, when, for example, meeting someone for the first time, interviewing someone for a job, or faced with making a decision quickly under stress.
Now, a new study from the University of Maryland School of Medicine (UMSOM) suggests that there may be a biological basis behind this instantaneous compatibility reaction. A team of researchers showed that variations of an enzyme found in a part of the brain that regulates mood and motivation seems to control which mice want to socially interact with other mice—with the genetically similar mice preferring each other.
These findings may indicate that similar factors could contribute to the social choices people make. Understanding what factors drive these social preferences may help us to better recognize what goes awry in diseases associated with social withdrawal, such as schizophrenia or autism, so that better therapies can be developed.
The study was published on July 28 inMolecular Psychiatry, a Nature publication.
But, let us wait till these results are reproduced several times before coming to a conclusion.
Abigail J. Smith et al, A genetic basis for friendship? Homophily for membrane-associated PDE11A-cAMP-CREB signaling in CA1 of hippocampus dictates mutual social preference in male and female mice, Molecular Psychiatry (2021). DOI: 10.1038/s41380-021-01237-4
Hidden bacterial hairs power nature's 'electric grid'
A hair-like protein hidden inside bacteria serves as a sort of on-off switch for nature's "electric grid," a global web of bacteria-generated nanowires that permeates all oxygen-less soil and deep ocean beds, researchers report in the journal Nature.
The ground beneath our feet, the entire globe, is electrically wired. These previously hidden bacterial hairs are the molecular switch controlling the release of nanowires that make up nature's electrical grid.
Almost all living things breathe oxygen to get rid of excess electrons when converting nutrients into energy. Without access to oxygen, however,soil bacterialiving deep under oceans or buried underground over billions of years have developed a way to respire by "breathing minerals," like snorkeling, through tiny protein filaments callednanowires.
Scientists had thought that the nanowires are made up of a protein called "pili" ("hair" in Latin) that many bacteria show on their surface. This work has reveal that this pili structure is made up of two proteins And instead of serving as nanowires themselves, pili remain hidden inside the bacteria and act like pistons, thrusting the nanowires into the environment. Previously nobody had suspected such a structure.
Just how these soil bacteria use nanowires to exhale electricity, however, has remained a mystery. Now that mystery has been solved.
Understanding how bacteria create nanowires will allow scientists to tailor bacteria to perform a host of functions—from combatting pathogenic infections or biohazard waste to creating living electrical circuits, the authors say. It will also assist scientists seeking to use bacteria to generate electricity, create biofuels, and even develop self-repairing electronics.
Social distancing has been a critical component of the world's response to the COVID-19 pandemic. The idea being that keeping physical apart from other people will reduce the risk of a person spreading the respiratory virus to someone else. It is just one component of our response, which also includes wearing face coverings, frequent hand sanitisation, and obtaining a vaccine against the virus.
New research in the International Journal of Sensor Networks discusses the potential of ultrasonic sensors to help people keep a safe distance from others when social distancing is deemed necessary in a pandemic situation.
Mohit Ghai and Ruchi Gupta of the Department of Electrical and Electronics Engineering at ADGITM, IP University in Delhi, India, describe a small, portable sensor-alarm device based on an Arduino system. Arduino is anopen-source hardwareandsoftware systemthat can be used to quickly build single-board microcontrollers and microcontroller kits with a variety of inexpensive applications. There is scope to add Wi-Fi capability and other networking functionality to a device too.
The team's Arduino device has an ultrasonic sensor that continuously probes the space around a person and is triggered when another person enters one'spersonal spacewithin a pre-determined threshold distance set according to social distancing rules. The system is not dissimilar to the parking sensors with which many vehicles are fitted and so could give a timely indication to the user that they have moved too close to another person unwittingly or alert them when another person moves nearer to them in a shopping queue or other setting, for instance.
Given how often people misjudge distances between themselves and others especially in busy environments, a portable alarm system of this sort could be a boon to those hoping to ensuresocial distancingis maintained to help reduce the risk of spreading infection.
Mohit Ghai et al, Ultrasonic sensor based social distancing device, International Journal of Sensor Networks (2021). DOI: 10.1504/IJSNET.2021.117227
Biologists Just Got Closer to The DNA Secrets That Stop Species From Interbreeding
We think of DNA as the vitally important molecules that carry genetic instructions for most living things, including ourselves. But not all DNA actually codes proteins; now, we're finding more and more functions involving the non-coding DNA scientists used to think of as 'junk'.
A new study suggests that satellite DNA – a type of non-coding DNA arranged in long, repetitive, apparently nonsensical strings of genetic material – may be the reason why different species can't successfully breed with each other.
It appears that satellite DNA plays an essential role in keeping all of a cell's individual chromosomes together in a single nucleus, through the work of cellular proteins.
According to biologists Madhav Jagannathan and Yukiko Yamashita who authored the new study, that important role is managed differently in each species, leading to genetic incompatibility. The clash of the different strategies between species may be what causes chromosomes to scatter outside of the nucleus, at least in part, preventing reproduction.
"We propose a unifying framework that explains how the widely observed satellite DNA divergence between closely related species can cause reproductive isolation," they write in their paper.
This "satellite DNA divergence" has been well established in previous research, leading to suspicions about its role in speciation. In the case of the chimpanzee genome and the human genome, for example, the protein-coding DNA is almost identical, while the 'junk' DNA is almost entirely different.
Study explores the influence of the X-chromosome on brain anatomy
Past neuroscience research suggests that common differences in people's genetic profiles can explain a significant proportion of variations in people's brain anatomy. In more specific terms, they found that neuroanatomical variation is partly explained by genetic variation.
Scientists have hypothesized that the X-chromosome has a particularly crucial influence on the brain, as it is known to be associated with the expression of many genes. In addition, several types of intellectual disabilities have been found to be related with mutations of genes on the X chromosome.
All existing studies investigating the role of genetics on brain anatomy excluded the X-chromosome, which accounts for about 5% of our genomes. it would be important to address this gap because—beyond the basic need to complete the missing analysis—there were lot of existing hints that the X-chromosome might actually have a special capacity to explain variation in brain anatomy.
So if a common genetic variation explains 30% of variation in total brain volume, then a chromosome which represents 10% of the genome would explain 3% of variation in total brain volume.
The X-chromosome consists of approximately 5% of the total genome. Taking this into consideration, researchers calculated the proportion of anatomical variation that could be explained by the X-chromosome. They found that given its known size and the percentage of the human genome it represents, the proportion they calculated differed significantly from the expected proportion.
The main take-aways from our studies are that the X-chromosome does indeed 'punch above its weight' in its capacity to explain differences in brain anatomy and that this phenomenon seems to be concentrated in particular brain systems important for complex thinking, decision making and action.
In terms of practical implications— this finding tells us that we really do need to put an end to exclusion of the X-chromosome from genetic analyses of the brain and related traits such as cognition and behavior.
The findings gathered by this team of researchers significantly enrich the current understanding of the X-chromosome's role in human neurodevelopment.
Birds and mammals evolve faster if their home is rising
The rise and fall of Earth's land surface over the last three million years shaped the evolution of birds and mammals, a new study has found, with new species evolving at higher rates where the land has risen most.
Researchers at the University of Cambridge have combined reconstructions of the Earth's changing surface elevations over the past three million years with data onclimate changeover this timeframe, and with bird andmammal species' locations. Their results reveal howspeciesevolved into new ones as land elevation changed—and disentangle the effects of elevation from the effects of climate.
The study found that the effect of elevation increase is greater
than that of historical climate change, and of present-day elevation andtemperature, in driving the formation ofnew species– 'or speciation'.
In contrast to areas where land elevation is increasing, elevation loss was not found to be an important predictor of where speciation happens. Instead, present-day temperature is a better indicator of speciation in these areas.
The results are published today in the journalNature Ecology and Evolution.
Nano 'camera' made using molecular glue allows real-time monitoring of chemical reactions
Researchers have made a tiny camera, held together with 'molecular glue' that allows them to observe chemical reactions in real time.
The device, made by a team from the University of Cambridge, combines tiny semiconductor nanocrystals calledquantum dotsand gold nanoparticles using molecular glue called cucurbituril (CB). When added to water with the molecule to be studied, the components self-assemble in seconds into a stable, powerful tool that allows the real-time monitoring of chemical reactions.
The camera harvests light within the semiconductors, inducing electron transfer processes like those that occur in photosynthesis, which can be monitored using incorporated gold nanoparticle sensors and spectroscopic techniques. They were able to use the camera to observechemical specieswhich had been previously theorized but not directly observed.
The platform could be used to study a wide range of molecules for a variety of potential applications, such as the improvement of photocatalysis and photovoltaics for renewable energy. The results are reported in the journalNature Nanotechnology.
Decaying forest wood releases 10.9 billion tons of carbon yearly, which will increase with climate change
If you've wandered through a forest, you've probably dodged dead, rotting branches or stumps scattered on the ground. This is "deadwood," and it plays several vital roles in forest ecosystems.
But there's another important role we have little understanding of on a global scale: thecarbondeadwood releases as it decomposes, with part of it going into the soil and part into the atmosphere. Insects, such as termites and wood borers, can accelerate this process.
The world's deadwood currently stores73 billion tonsof carbon.Our new research in Naturehas, for the first time, calculated that 10.9 billion tons of this (around 15%) is released into the atmosphere and soil each year—a little more thanthe world's emissions from burning fossil fuels.
But this amount can change depending on insect activity, and will likely increase underclimatechange. It's vital deadwood is considered explicitly in all future climate change projections.
Sebastian Seibold et al, The contribution of insects to global forest deadwood decomposition, Nature (2021). DOI: 10.1038/s41586-021-03740-8
Methane contributes to global warming; it is therefore a greenhouse gas. Of all the methane produced in some developed countries, 70% comes from livestock farming. A substantial percentage. But how harmful is it? Because, unlike other greenhouse gasses, methane breaks down relatively quickly in the atmosphere.
Greenhouse gasses are important. They form a blanket around the earth. Without greenhouse gasses, it would be unbearably cold on earth. The problem with the greenhouses gasses is that we too much of them. The blanket becomes so thick, that the earth's temperature rises. This causes periods of drought and in other places too much precipitation, the polar caps melt, and so on.
there are three greenhouse gasses: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Roughly speaking, you can say that all three are created during the breakdown or combustion of organic substances. CO2(and NOx) are mainly created through the combustion of diesel, lignite or gasoline. Not only in transport and traffic, but also in production processes. From the concrete in your house to the staples in your furniture, almost everything in our lives produces CO2during its production.
Methane is released during the breakdown of organic substances. For example, in the gastrointestinal tract of animals. Ruminants (cows, goats, sheep) in particular produce a lot of methane. Methane is also 34 times more powerful thancarbon dioxide. So, the earth warms up extra fast when there is more methane in the atmosphere. N2O is created in processes where nitrogen compounds play a role: in manure storage and manure application."
CO2stays in the atmosphere for a very, very long time. Many thousands of years. So thatgreenhouse gasaccumulates, and the 'blanket' around the earth thickens. The unique thing about methane is that it halves in the atmosphere in just over 8 years. The other half becomes CO2. So if you emit 100 kilos of methane today, in 8.5 years there will be 50 kilos left, and after another 8.5 years only 25 kilos, and so on," Vellinga explains. "That CO2has gone through what is known as the short carbon cycle: it was converted by grass, corn, etc. into plant material, which the cow converts back into CO2and CH4. And that CH4becomes CO2again pretty quickly. Nothing to worry about, you might say."
"But be careful not to make the problem too small. Before you know it, it seems as if there is nothing wrong with methane. On the contrary. As long as methane is in the atmosphere, it contributes very strongly to warming. Over the lifetime of methane, this is as much as 80 to 100 times more than CO2.
But the advantage is that it disappears quickly. Reducingmethane emissionscan cause the concentration of methane in the atmosphere to drop and therefore even reduce the greenhouse effect. When reducing CO2, the current greenhouse effect remains the same and only does not increase. So reducingmethaneis more effective than reducing CO2. But it has to be done both ways."
Drug cocktail reduces aging-associated disc degeneration
Chronic back pain affects millions of adults in the world. Degeneration of the discs that cushion and support vertebrae, a common occurrence of aging, is a major contributor to low back pain. Although a widespread condition, few treatments are available.
With age, every tissue in the body accumulates senescent cells. Senescent cells secrete destructive enzymes and inflammatory proteins that affect nearby healthy cells. Senolytic drugs remove these deteriorating cells, leaving room for new cells to replace them. The idea is that removing senescent cells from a tissue will improve the tissue's function.
New research has shown that treating mice with a drug cocktail that removes aging cells reduces disc degeneration. The findings, reported in Nature Communications on September 3rd, show how a novel approach to preventing age-related disc degeneration may pave the way for treating chronic back pain.
The findings show that senolytic drugs—ones already approved for use in clinical trials—can mitigate disc degeneration that occurs with aging.
Just because the drugs work in one tissue doesn't mean they will also work in another. Every tissue is different and should be treated differently.
Young and middle-aged mice given the senolytic cocktail showed less disc degeneration and fewer senescent cells by the time they reached an advanced age compared to mice given a placebo.
"Long-term treatment with senolytic drugs Dasatinib and Quercetin ameliorates age-dependent intervertebral disc degeneration in mice." Nature Communications (2021) , DOI: 10.1038/s41467-021-25453-2
The first cells might have used temperature to divide
A simple mechanism could underlie the growth and self-replication of protocells—putative ancestors of modern living cells—suggests a study publishing September 3 in Biophysical Journal. Protocells are vesicles bounded by a membrane bilayer and are potentially similar to the first unicellular common ancestor (FUCA). On the basis of relatively simple mathematical principles, the proposed model suggests that the main force driving protocell growth and reproduction is the temperature difference that occurs between the inside and outside of the cylindrical protocell as a result of inner chemical activity.
The purpose of this study was to identify the main forces driving cell division. This is important because cancer is characterized by uncontrolled cell division. This is also important to understand the origin of life.
The splitting of a cell to form two daughter cells requires the synchronization of numerous biochemical and mechanical processes involving cytoskeletal structures inside the cell. But in the history of life, such complex structures are a high-tech luxury and must have appeared much later than the ability to split. Protocells must have used a simple splitting mechanism to ensure their reproduction, before the appearance of genes, RNA, enzymes, and all the complex organelles present today, even in the most rudimentary forms of autonomous life.
In the new study, researchers proposed a model based on the idea that the early forms of life were simple vesicles containing a particular network of chemical reactions—a precursor of modern cellular metabolism. The main hypothesis is that molecules composing the membrane bilayer are synthesized inside the protocell through globally exothermic, or energy-releasing, chemical reactions.
The slow increase of the inner temperature forces the hottest molecules to move from the inner leaflet to the outer leaflet of the bilayer. This asymmetric movement makes the outer leaflet grow faster than the inner leaflet. This differential growth increases the mean curvature and amplifies any local shrinking of the protocell until it splits in two. The cut occurs near the hottest zone, around the middle.
The scenario described can be viewed as the ancestor of mitosis. Having no biological archives as old as 4 billion years, we don't know exactly what FUCA contained, but it was probably a vesicle bounded by a lipid bilayer encapsulating some exothermic chemical reactions.
Although purely theoretical, the model could be tested experimentally.
Unified theory explains how materials transform from solids to liquids
A new study unveils a unified mathematical expression that defines how soft-yet-rigid materials transition from a solid into a liquid flow when they exceed their specific stress threshold.
This study has shown that these physical states—solid and liquid—can exist together in the same material, and we can explain it using one mathematical expression.
To develop this model, the team performed numerous studies that subjected a variety of different soft materials to stress while measuring the individual solidlike and liquidlike strain responses using a device called a rheometer.
The researchers were able to observe a material's behavior and see a continuous transition between the solid and liquid states and were able to resolve two distinct behaviors that reflect energy dissipation via solid and fluid mechanisms.
Krutarth Kamani et al, Unification of the Rheological Physics of Yield Stress Fluids, Physical Review Letters (2021). DOI: 10.1103/PhysRevLett.126.218002
Fish eyes grown in a petri dish from embryonic stem cells
A research team has demonstrated that complex retinal tissue can be cultured in a Petri dish from embryonic stem cells of bony fish. Until now, stem cells from mammals, including humans, have been used in organoid research. For the first time, researchers have demonstrated that stem cells from medaka and zebrafish can also form highly organized neural structures under controlled laboratory conditions. Among other things, the researchers expect to gain new insights into the basic mechanisms of retinal development.
Organoids are bits of tissue that are grown from stem cells and resemble actual organs. They are used in basic research to gain new information on cell organization and organ development, to investigate the origin of disease, and to develop and test new medications. The major advantage of fish organoids is that they are highly reproducible, unlike organoids from mammalian stem cells. They develop reliably and very quickly and enable a direct comparison with living embryos that in fish grow outside of the womb.
Researchers are now able to manipulate the molecular and genetic mechanisms of retina formation.
Researchers used pluripotent stem cells from medaka and zebrafish embryos. Such cells have not yet differentiated and can potentially develop into many different cell types. All the cells taken from a single embryo independently aggregated into one large retina within 24 hours. In a matter of a few days, it then formed layers of different cell types that are also found in the fish eye, including photoreceptor cells, bipolar cells, amacrine cells, and ganglion cells. The growth process proved to be incredibly efficient. Hundreds of small retina organoids could be generated within a day. The high throughput allowed the researchers to precisely isolate the conditions in which structures resembling a head with two eyes, including both brain and retina, are formed.
Lucie Zilova et al, Fish primary embryonic pluripotent cells assemble into retinal tissue mirroring in vivo early eye development, eLife (2021). DOI: 10.7554/eLife.66998
Coronavirus epidemics first hit more than 21,000 years ago
Sarbecoviruses have crossed into humans twice in the last decade, leading to the deadly SARS-CoV-1 outbreak in 2002-04 and the current COVID-19 pandemic, caused by the SARS-CoV-2 virus. A new Oxford University study, published today, shows that the most recent common ancestor of these viruses existed more than 21,000 years ago, nearly 30 times older than previous estimates.
Despite having a very rapid rate of evolution over short timescales, to survive, viruses must remain highly adapted to their hosts—this imposes severe restrictions on their freedom to accumulate mutations without reducing their fitness. This causes the apparent rate of evolution of viruses to slow down over time. The new research, for the first time, successfully recreates the patterns of this observed rate decay in viruses.
The study also demonstrates that while existingevolutionary modelshave often failed to measure the divergence betweenvirusspecies over periods—from a few hundred to a few thousands of years—theevolutionary frameworkdeveloped in this study will enable the reliable estimation of virus divergence across vast timescales, potentially over the entire course of animal and plant evolution.
The new model enables us to not only reconstruct the evolutionary history of viruses related to SARS-CoV-2, but also a much wider range of RNA and DNA viruses during more remote periods in the past.
Mahan Ghafari et al, A mechanistic evolutionary model explains the time-dependent pattern of substitution rates in viruses, Current Biology (2021). DOI: 10.1016/j.cub.2021.08.020
Hormones May Contribute to Asymmetrical Effects of Brain Injury
Researchers studying rats claim to have found a novel connection between damage on one side of the brain and problems with the posture or movement of limbs on the opposite side of the body.
Injury to one side of the brain can cause abnormalities in posture or movement on the opposite side of the body. These effects, which are sometimes seen in people who have suffered a stroke or head trauma, have typically been attributed to neural pathways that link the right side of the brain to spinal cord neurons controlling muscles on the left side of the body, and vice versa.
But in a new study on rats that had their spinal cords severed, researchers claim to have discovered another, parallel pathway that triggers opposite-side effects following brain injury and might instead operate via hormones circulating in the blood.
If similar mechanisms operate in humans, it’s conceivable that drugs blocking receptors for particular hormones could help treat some of the physical effects of brain injury
“Mystery Fever” Claims the Lives of Dozens of Indian Children
So far, more than 50 people have died of a febrile illness, though the cause isn’t clear.
In addition to the ongoing COVID-19 pandemic and anuptickof malaria cases across the country, an unknown disease has killed more than 50 people in the state of Uttar Pradesh, India in the last week; most were children. All of the patients tested negative for COVID-19, andIndia Todayreports it is likely thatscrub typhusis to blame, though other possibilities, such as dengue, have not been ruled out.
The Hindustan Timesreports, and monsoon season has brought a greater number of mosquito-borne illnesses. Now, many regions in the state are reporting illness and death due to a mystery fever.
Water-logging, and lack of sanitation and hygiene are the reasons behind the disease spread. The patients, especially children, in hospitals are dying very quickly.
According to multiple news outlets, the hundreds of people hospitalized by the illness have experienced fever, headaches, joint pain, nausea, rashes, and dehydration. A drop in platelet count has also been observed in many fatal cases. Though many of these symptoms can occur in severe dengue cases,The Hindustan Timesand others report that the likely culprit is a bacterial disease called scrub typhus.
Scrub typhus can occur after a person is bitten by chiggers infected withOrientia tsutsugamushibacteria. According to theBBC, these mites live on plants that flourish after the monsoon rains, and they can hitchhike into people’s homes on firewood. The symptoms ofO. tsutsugamushi infection largely overlap with what has been seen in the patients.
According to the US Center for Disease Control and Prevention (CDC), there are no vaccinations for scrub typhus and it should be treated with the antibiotic doxycycline. The agency recommends covering exposed skin to prevent chigger bites.
Biomedical Innovations from Women Less Likely to be Adopted: Study
An analysis of scientists’ networks finds discrepancies in the diffusion of novel ideas through communities.
A study published Monday (August 30) by the National Bureau of Economic Research finds that new ideas in biomedical research are less likely to spread when they are generated by women and minorities than when generated by men.
The authors of the study, which was not peer-reviewed, used a computational technique called natural language processing to scan titles and abstracts in MEDLINE for novel one, two, or three-word phrases originating in biomedical research papers published between 1980 and 2008. The researchers ranked these phrases by the total number of mentions they received in the year when they first appeared and analyzed the top 0.1 percent of phrases for each year to assess whether each represented an actual new idea or scientific innovation.
Ideas generated by teams of mostly male innovators were mentioned just over one percent more frequently in subsequent titles and abstracts than ideas generated by mostly female teams over a period of five years after they were first published.
Biomedical Innovations from Women Less Likely to be Adopted: Study
An analysis of scientists' networks finds discrepancies in the diffusion of novel ideas through communities.
Why words become harder to remember as we get older
As we get older, we find it increasingly difficult to have the right words ready at the right moment, even though our vocabulary actually grows continuously over the course of our lives. Until now, it was unclear why this is. Researchers have now found out: It is the networks in the brain that change their communication over time. This makes them more inefficient.
The researchers investigated these connections with the help of two groups - younger study participants between the ages of 20 and 35 and older ones between the ages of 60 and 70. Both groups were asked to name words in the MRI scanner that belong to certain categories, including animals, metals or vehicles.
It became clear that both age groups were good at finding words. However, the younger ones were somewhat faster. The reason for this could be the different brain activities. For one thing, not only were the language areas themselves more active in the younger ones. They also showed a more intensive exchange within two decisive networks: the network for semantic memory, in which factual knowledge is stored, and the executive network, which is responsible for general functions such as attention and memory.
The reverse was true for older people. Here, executive areas showed stronger activity, indicating that the task was more difficult for these individuals overall. In addition, the exchange within the crucial networks was less effective than in the younger people. The older group was most likely to benefit from inter-network exchange, but this is associated with losses. Communication within neuronal networks is more efficient and thus faster than between them.
Why these activity patterns shift with age has not yet been fully explained. One theory, says Martin, is that as people age, they rely more on the linguistic knowledge they have, so exchanges between networks come into focus, while younger people rely more on their fast working memory and cognitive control processes. On the structural level, the loss of grey matter in the brain could also play a role, which is compensated for by the exchange between networks.
Sport science: How do swimmers control their front crawl swimming velocity?
A research team has reviewed the hydrodynamics literature related to swimming. They identified certain biomechanical aspects, including the relationship between velocity and drag forces, that are not completely understood. This work may help direct future research that could improve the performance of competitive swimmers.
The recent Tokyo Olympics provided impressive feats of speed in the pool, with elite athletes setting many new Olympic and World records. What viewers might not realize, however, is the complexity of the science underlying the sometimes split-second difference between winning a gold medal and going home empty-handed. Biomechanics, the study of motion of the body, and hydrodynamics, the area of physics dealing with fluid flows, contain many questions that remain poorly understood—and swimming fits right at the intersection of these topics. For swimmers who participate in races, even a tiny advance in knowledge can led to a competitive edge.
Now, a team of researchers has drawn together research on front crawl swimming biomechanics, focusing on propulsive and resistive forces at different swimming velocities, to form a more complete picture of the relationships between the critical variables. New knowledge of swimming energetics and fluid mechanics has improved our understanding of factors that determine swimming performance.
One of the most important relationships to understand is how resistive forces, like drag when moving through the water, depend on the speed of the swimmer. The researchers looked at recent studies that indicated the resistive force increases in proportion to the cube of the velocity. To compensate, swimmers may try to increase their stroke frequency. However, this has limitations. Researchers inferred from experimental and simulation studies that there is a maximum frequency beyond which swimmers cannot further increase swimming velocity due to a change in the angle of attack of the hand that reduces its propulsive force. The different balance of forces at different swimming speeds also means that optimal technique may differ between long-distance and short-distance swimming.
The team also identified conflicting evidence over the effectiveness of kicking for increasing the speed of high-velocity front crawl. This indicates an opportunity to further optimize competitive swimming technique if future research can further unpack the relevant hydrodynamic factors.
The researchers found that certain simplified models of swimming often break down when trying to model more realistic conditions. For example, swimmers are not simply 'pushing' or 'pulling' the water to increase their velocity, as some textbooks frame it. This is because the increase in the negative pressure acting on the dorsal side of the hand is crucial for increasing propulsion. Therefore, teaching the proper technique is important, even for phases considered to be non-propulsive.
Hideki Takagi et al, How do swimmers control their front crawl swimming velocity? Current knowledge and gaps from hydrodynamic perspectives, Sports Biomechanics (2021). DOI: 10.1080/14763141.2021.1959946
Fridge-free COVID-19 vaccines grown in plants and bacteria
Nanoengineers have developed COVID-19 vaccine candidates that can take the heat. Their key ingredients? Viruses from plants or bacteria.
The new fridge-free COVID-19 vaccines are still in the early stage of development. In mice, the vaccine candidates triggered high production of neutralizing antibodies against SARS-CoV-2, the virusthat causes COVID-19. If they prove to be safe and effective in people, the vaccines could be a big game changer for global distribution efforts, including those in rural areas or resource-poor communities.
What's exciting about this vaccine technology is that is thermally stable, so it could easily reach places where setting up ultra-low temperature freezers, or having trucks drive around with these freezers, is not going to be possible.
The researchers created two COVID-19 vaccine candidates. One is made from aplant virus, called cowpea mosaic virus. The other is made from a bacterial virus, or bacteriophage, called Q beta.
Both vaccines were made using similar recipes. The researchers used cowpea plants andE. colibacteria to grow millions of copies of the plant virus and bacteriophage, respectively, in the form of ball-shaped nanoparticles. The researchers harvested these nanoparticles and then attached a small piece of the SARS-CoV-2 spike protein to the surface. The finished products look like an infectious virus so the immune system can recognize them, but they are not infectious in animals and humans. The small piece of the spike protein attached to the surface is what stimulates the body to generate an immune response against the coronavirus.
The researchers note several advantages of using plant viruses and bacteriophages to make their vaccines. For one, they can be easy and inexpensive to produce at large scales.
Another big advantage is that the plant virus and bacteriophage nanoparticles are extremely stable at high temperatures. As a result, the vaccines can be stored and shipped without needing to be kept cold.
Trivalent subunit vaccine candidates for COVID-19 and their delivery devices, Journal of the American Chemical Society (2021). DOI: 10.1021/jacs.1c06600
Earth is round. So are other planets in the solar system.
When you drop anything, gravity causes it to fall directly toward the center of the Earth, at least until it hits the ground. Gravity is a force that is caused by nearly everything that has mass. Mass is a measure of how much material there is in anything. It could be in the form of rocks, water, metal, people – anything. Everything material has mass, and therefore everything causes gravity. Gravity always pulls toward the center of mass.
The Earth and all planets are round because when the planets formed, they were composed of molten material – essentially very hot liquid. Since gravity always points toward the center of a mass, it squeezed the stuff the Earth is made of equally in all directions and formed a ball. When the Earth cooled down and became a solid, it was a round ball. If the Earth didn’t spin, then it would have been a perfectly round planet. Scientists call something that is perfectly round in all directions a “sphere.”
If you ever played on a merry-go-round, you know that the spinning merry-go-round tends to throw you off. The faster it spins, the harder it is to stay on. This tendency to be flung off is called centrifugal force and pushes the mass on the equator outward. This makes the planet bulge at the equator.
The faster the spin, the more unround it becomes. Then, when it cools and hardens, it retains that shape. If a molten planet starts off spinning faster, it would be less round and have a bigger bulge.
The planet Saturn is very oblate – non-spherical – because it rotates very fast. Because of gravity, all planets are round, and because they rotate at different rates, some have fatter equators than their poles. So the shape of the planet and the speed and direction that it rotates depends on the initial condition of the material out of which it forms.
Hundreds of Medical Journals Just United Together to Issue a Brutally Frank Warning
Global warming is already affecting people's health so much that emergency action on climate change cannot be put on hold while the world deals with the COVID-19pandemic, medical journals across the globe warned on Monday.
Health is already being harmed by global temperature increases and the destruction of the natural world," read an editorial published in more than 220 leading journals ahead of the COP26 climate summit in November.
Since the pre-industrial era, temperatures have risen around 1.1 degrees Celsius.
The editorial, written by the editors-in-chief of over a dozen journals including theLancet, theEast African Medical Journal, Brazil'sRevista de Saude Publicaand theInternational Nursing Review,said this had caused a plethora of health problems.
"In the past 20 years, heat-related mortality among people older than 65 years has increased by more than 50 percent,"it read.
"Higher temperatures have brought increased dehydration and renal function loss, dermatological malignancies, tropical infections, adverse mental health outcomes, pregnancy complications, allergies, and cardiovascular and pulmonary morbidity and mortality."
NASA Testing Electric 'Air Taxi' Prototype Designed to Carry Passengers in The Sky
NASA is commonly thought of as America's space agency, but its name also emphasizes another research area. The National Aeronautics and Space Administration is also America's civilian aerospace research organization.
Scientists create artificial cells that mimic living cells' ability to capture, process, and expel material
Researchers have developed artificial cell-like structures using inorganic matter that autonomously ingest, process, and push out material—recreating an essential function of living cells.
Their article, published inNature, provides a blueprint for creating "cell mimics," with potential applications ranging fromdrug deliveryto environmental science.
A fundamental function of livingcellsis their ability to harvest energy from the environment to pump molecules in and out of their systems. When energy is used to move these molecules from areas of lower concentration to areas of higher concentration, the process is called active transport. Active transport allows cells to take in necessary molecules like glucose or amino acids, store energy, and extract waste.
For decades, researchers have been working to create artificial cells—engineered microscopic structures that emulate the features and behavior of biological cells. But these cell mimics tend to lack the ability to perform complex cellular processes like active transport.
In theNaturestudy, researchers describe a new, fully synthetic cell mimic that is one step closer to replicating the function of living cells. When deployed in mixtures of different particles, the cell mimics can perform active transport tasks by autonomously capturing, concentrating, storing, and delivering microscopic cargo. These artificial cellsare fabricated using minimal ingredients and borrow no materials from biology.
To design the cell mimics, the researchers created a spherical membrane the size of a red blood cell using a polymer, a stand-in for the cellular membrane that controls what goes in and out of a cell. They pierced a microscopic hole into the spherical membrane creating a nano-channel through which matter can be exchanged, imitating a cell's protein channel.
But in order to perform the tasks required for active transport, the cell mimics needed a mechanism to power the cell-like structure to pull in and expel material. In aliving cell, mitochondria and ATP provide the necessary energy for active transport. In the cell mimic, the researchers added a chemically reactive component inside the nano-channel that, when activated by light, acts as a pump. When light hits the pump, it triggers a chemical reaction, turning the pump into a tiny vacuum and pulling cargo into the membrane. When the pump is switched off, the cargo is trapped and processed inside the cell mimic. And when the chemical reaction is reversed, the cargo is pushed out on demand.
Common medications accumulate in gut bacteria, which may reduce drug effectiveness and alter the gut microbiome
Common medications can accumulate in gut bacteria, a new study has found, altering bacterial function and potentially reducing the effectiveness of the drug. These interactions—seen for a variety of medications, such as depression, diabetes, and asthma drugs—could help researchers to better understand individual differences in drug effectiveness and side-effects, according to the study published in Nature.
It is known that bacteria can chemically modify some drugs, a process known as biotransformation. This study is the first to show that certain species of gut bacteria accumulate human drugs.
This could change the effectiveness of thedrugboth directly, as the accumulation could reduce the availability of the drug to the body, and indirectly, as altered bacterial function and composition could be linked toside-effects.
The human gut naturally contains communities of hundreds of different species of bacteria, which are important in health and disease, called thegut microbiome. The composition of bacterial species varies significantly between people and has previously been shown to be associated with a wide range of conditions including obesity, immune response, and mental health.
In this study, the researchers grew 25 common gut bacteria and studied how they interacted with 15 drugs that are taken orally. The drugs were chosen to represent a range of different types of common drugs, including antidepressant medications, which are known to affect individuals dissimilarly and cause side effects such as gut problems and weight gain.
The researchers tested how each of the 15 drugs interacted with the selected bacterial strains—a total of 375 bacteria-drug tests.
They found 70 interactions between the bacteria and the drugs studied—of which 29 had not been previously reported.
While earlier research has shown bacteria can chemically modify drugs, when the scientists studied these interactions further, they found that for 17 of the 29 new interactions, the drug accumulated within the bacteria without being modified.
COVID, vaccine misinformation spread by hundreds of websites, analysis finds
More than 500 websites have promoted misinformation about the coronavirus—including debunked claims about vaccines, according to a firm that rates the credibility of websites.
NewsGuard announced Wednesday that, of the more than 6,700 websites it has analyzed, 519 have publishedfalse informationabout COVID-19. Some of the sites publish dubious health information or political conspiracy theories, while others were "created specifically to spread misinformation about COVID-19," the company says on its website.
It's become virtually impossible for people to tell the difference between a generally reliable site and an untrustworthy site. And that is why there is such a big business in publishing this information. They're all hoaxes that have gained traction, and we know that because we see them spreading from website to website. Some of the websites NewsGuard identified have become more popular online than trustworthy sources of information about COVID-19.
Chemical impurities in tap water can cause a thin film to form on the surface of a cup of tea, and these make it taste better than a drink made with pure water, according to researchers at ETH Zurich in Switzerland.
Pour yourself a cup of tea and leave it to cool slightly, and you may see a film on the surface that cracks like sea ice when you disturb the cup. There are many factors that affect the formation of this film, the researchers say, but the primary one is calcium carbonate in the water. When tap water contains a high amount of minerals such as calcium carbonate, it is called hard water.
“Tap water in many regions comes from limestone aquifers, where calcium carbonate, a harmless compound that can make water taste ‘crisper’, is found.
Other factors that affect the formation of this film include milk, sugar or lemon added to the tea, the brewing temperature, and the concentration of the tea.
The team studied how the strength of the film changed with water hardness by placing a metal device on the surface of the tea and rotating it. “The rotation of that device is carefully controlled, and the resistance to rotation that the film applies is what allows us to determine its strength.
The team’s findings could be useful in industrial settings, where creating conditions to form a strong film could improve the shelf life in packaged tea drinks.
Exposure to traffic noise linked to higher dementia risk
Exposure to noise from traffic on roads and railways over a long period is associated with a higher risk of developing dementia, especially Alzheimer's disease, suggests a study published in The BMJ recently.
The researchers estimate that as many as 1,216 out of the 8,475 cases of dementiaregistered in Denmark in 2017 could be attributed to these noise exposures, indicating a great potential for dementia prevention through reduction in traffic related noise.
Worldwide, the number of people with dementia is expected to exceed 130 million by 2050, making it a costly and growing global health crisis. Besides well established risk factors, such as cardiovascular diseases and unhealthy lifestyle, environmental exposures may also play a role in the development of dementia.
Transportation noise is considered the second worst environmental risk factor for public healthin Europe after air pollution, and around a fifth of the European population is exposed to transportation noise above the recommended level of 55 dB (decibels).
Studies have consistently linked transportation noise to various diseases and health conditions, such as coronary heart disease, obesity, and diabetes. There is, however, little research on transportation noise and dementia and findings are inconsistent.
To address this, researchers investigated the association between long term residential exposure to road traffic and railway noise and risk of dementia among two million adults aged over 60 and living in Denmark between 2004 and 2017.
The researchers estimated road traffic and railway noise at the most and least exposed sides (or façades) of all residential addresses in Denmark.
They then analyzed national health registers to identify cases of all-cause dementia and different types of dementia (Alzheimer's disease, vascular dementia, and Parkinson's disease related dementia) over an average of 8.5 years.
They found 103,500 new cases of dementia during the study period.
After taking account of potentially influential factors related to residents and their neighborhoods, the researchers found that a 10-year average exposure to road traffic and railway noise at the most and least exposed sides of buildings was associated with a higher risk of all-cause dementia.
These associations showed a general pattern of higher risk with higher noise exposure, but with a leveling off or even small declines in risk at higher noise levels.
Further analysis by type of dementia showed both road traffic and railway noise were associated with a higher risk of Alzheimer's disease—up to 27% higher for exposure to road traffic noise of 55 dB and up to 24% higher for exposure to railway noise of 50 dB compared with less than 40 dB.
However, only road trafficnoise was associated with an increased risk of vascular dementia, and not railway noise.
Residential exposure to transportation noise in Denmark and incidence of dementia: national cohort study, BMJ (2021). www.bmj.com/content/374/bmj.n1954
Scientists solve mystery of icy plumes that may foretell deadly supercell storms
The most devastating tornadoes are often preceded by a cloudy plume of ice and water vapor billowing above a severe thunderstorm. New research reveals the mechanism for these plumes could be tied to 'hydraulic jumps' -- a phenomenon Leonardo Da Vinci observed more than 500 years ago.
When a cloudy plume of ice and water vapor billows up above the top of a severe thunderstorm, there's a good chance a violent tornado, high winds or hailstones bigger than golf balls will soon pelt the Earth below.
A new Stanford University-led study, published Sept. 10 inScience, reveals the physical mechanism for these plumes, which form above most of the world's most damaging tornadoes.
Previous research has shown they're easy to spot in satellite imagery, often 30 minutes or more before severe weather reaches the ground. "The question is, why is this plume associated with the worst conditions, and how does it exist in the first place? That's the gap that we are starting to fill," said atmospheric scientist Morgan O'Neill, lead author of the new study.
The research comes just over a week after supercell thunderstorms and tornadoes spun up among the remnants of Hurricane Ida as they barreled into the U.S. Northeast, compounding devastation wrought across the region by record-breaking rainfall and flash floods.
Understanding how and why plumes take shape above powerful thunderstorms could help forecasters recognize similar impending dangers and issue more accurate warnings without relying on Doppler radar systems, which can be knocked out by wind and hail -- and have blind spots even on good days. In many parts of the world, Doppler radar coverage is nonexistent.
"If there's going to be a terrible hurricane, we can see it from space. We can't see tornadoes because they're hidden below thunderstorm tops. We need to understand the tops better," said O'Neill, who is an assistant professor of Earth system science at Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth).
The thunderstorms that spawn most tornadoes are known as supercells, a rare breed of storm with a rotating updraft that can hurtle skyward at speeds faster than 150 miles an hour, with enough power to punch through the usual lid on Earth's troposphere, the lowest layer of our atmosphere.
In weaker thunderstorms, rising currents of moist air tend to flatten and spread out upon reaching this lid, called the tropopause, forming an anvil-shaped cloud. A supercell thunderstorm's intense updraft presses the tropopause upward into the next layer of the atmosphere, creating what scientists call an overshooting top. "It's like a fountain pushing up against the next layer of our atmosphere," O'Neill said.
As winds in the upper atmosphere race over and around the protruding storm top, they sometimes kick up streams of water vapor and ice, which shoot into the stratosphere to form the tell-tale plume, technically called an Above-Anvil Cirrus Plume, or AACP.
The rising air of the overshooting top soon speeds back toward the troposphere, like a ball that accelerates downward after cresting aloft. At the same time, air is flowing over the dome in the stratosphere and then racing down the sheltered side.
Using computer simulations of idealized supercell thunderstorms, O'Neill and colleagues discovered that this excites a downslope windstorm at the tropopause, where wind speeds exceed 240 miles per hour. "Dry air descending from the stratosphere and moist air rising from the troposphere join in this very narrow, crazy-fast jet. The jet becomes unstable and the whole thing mixes and explodes in turbulence," O'Neill said. "These speeds at the storm top have never been observed or hypothesized before."
Scientists have long recognized that overshooting storm tops of moist air rising into the upper atmosphere can act like solid obstacles that block or redirect airflow. And it's been proposed that waves of moist air flowing over these tops can break and loft water into the stratosphere. But no research to date has explained how all the pieces fit together.
The new modeling suggests the explosion of turbulence in the atmosphere that accompanies plumed storms unfolds through a phenomenon called a hydraulic jump. The same mechanism is at play when rushing winds tumble over mountains and generate turbulence on the downslope side, or when water speeding smoothly down a dam's spillway abruptly bursts into froth upon joining slower-moving water below.
Leonardo DaVinci observed the phenomenon in flowing water as early as the 1500s, and ancient Romans may have sought to limit hydraulic jumps in aqueduct designs. But until now atmospheric scientists have only seen the dynamic induced by solid topography. The new modeling suggests a hydraulic jump can also be triggered by fluid obstacles in the atmosphere made almost entirely of air and which are changing shape every second, miles above the Earth's surface.
The simulations suggest the onset of the jump coincides with a surprisingly rapid injection of water vapor into the stratosphere, upwards of 7000 kilograms per second. That's two to four times higher than previous estimates. Once it reaches the overworld, water may stay there for days or weeks, potentially influencing the amount and quality of sunlight that reaches Earth via destruction of ozone in the stratosphere and warming the planet's surface. "In our simulations that exhibit plumes, water reaches deep into the stratosphere, where it possibly could have more of a long-term climate impact," said co-author Leigh Orf, an atmospheric scientist at the University of Wisconsin-Madison.
According to O'Neill, high-altitude NASA research aircraft have only recently gained the ability to observe the three-dimensional winds at the tops of thunderstorms, and have not yet observed AACP production at close range. "We have the technology now to go verify our modeling results to see if they're realistic," O'Neill said. "That's really a sweet spot in science."
This research was supported by the National Science Foundation and the NASA Precipitation Measurement Mission and Ground Validation program.
Story Source:
Materialsprovided byStanford University. Original written by Josie Garthwaite.Note: Content may be edited for style and length.
Journal Reference:
Morgan E O’Neill, Leigh Orf, Gerald M. Heymsfield, Kelton Halbert.Hydraulic jump dynamics above supercell thunderstorms.Science, 2021; 373 (6560): 1248 DOI:10.1126/science.abh3857
Techniques that have helped scientists to understand COVID-19 havescooped two out of five of the most lucrative awards in science and.... “These two awards are for research that has had such an impact on the world that they elevate the stature of the Breakthrough Prize,” says chemical biologist Yamuna Krishnan. “They have been saving lives by the millions.” This year’s US$3-million Breakthrough prizes went to:
Biochemists Katalin Karikó and Drew Weissman, who discovered how to smuggle genetic material called messenger RNA into cells, leading to the development of a new class of vaccine. Karikó recalls the scepticism surrounding her work in the 1990s that led to numerous grant-proposal and paper rejections (including the 2005 paper for which she is now being recognized), and forced her to take a demotion and a pay cut.
Chemists Shankar Balasubramanian, David Klenerman and Pascal Mayer, who developed the next-generation sequencing technique that has been used to rapidly track variants of the SARS-CoV-2 coronavirus.
Chemical biologist Jeffrey Kelly, for working out the part that protein misfolding plays in amyloidosis, a disease that can affect the heart and other organs and cause neurodegeneration — and for developing an effective treatment.
Optical physicists Hidetoshi Katori and Jun Ye, for inventing the optical lattice clock — a device that would lose less than one second over 15 billion years, improving the precision of time measurements by 10,000 times.
Mathematician Takuro Mochizuki, for extending the understanding of algebraic structures called ‘holonomic D-modules’ — which are related to certain types of differential equation — to deal with points at which the equations under study are not well defined.
Dr. Krishna Kumari Challa
Researchers take step toward using cellular motion to help wound healing
With a technique that overcomes cells' innate social behaviors, researchers have taken an important step in directing skin cells to migrate en masse to close wounds—"literally making skin crawl".
In a new study, the researchers overcame the inertia typical of mature skin tissue by breaking the molecular connections between cells, applying an electrical field to direct their migration and then rebuilding the connections. This novel approach improves the controllability of tissues and may one day help optimize wound healing through electrical stimulation.
Research showed that cells in the body can sense and follow an electric field, a process called electrotaxis. Electric fields generated in the body promote healing by directing cells to move toward the wound and are also vital for growth and development.
Despite promising clinical evidence from decades of use in patients, scientists have yet to work out how cells detect and respond to electric fields or how electrical stimulation can best be applied therapeutically. "It's kind of a black box
Gawoon Shim et al, Overriding native cell coordination enhances external programming of collective cell migration, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2101352118
part1
Sep 1, 2021
Dr. Krishna Kumari Challa
In their previous work, Cohen's group used electric fields to program thousands of individual cells to move in circles and around corners. Their new study used a model of more mature skin—a single layer of mouse skin cells all latched together—which is harder to control. Instead of moving with the speed and precision of a marching band in response to an electric current, the mature skin cells inched along like a crowd of people holding hands with their neighbors.
The mature skin also posed another problem: Once the leading edge of cells advanced, it would peel away from the petri dish and die. "If you apply a command that differs from what the cells naturally 'want' to do, you get a tug-of-war. The result was the tissues ripped themselves apart.
Cohen and Shim suspected that the "handshakes" between cells prevented the tissue from fluidly following the electrical commands. These handshakes are proteins called cadherins that anchor neighboring cells together. They make tissues cohesive so they can move together but can also create traffic jams when cells don't have space to move.
Gawoon Shim et al, Overriding native cell coordination enhances external programming of collective cell migration, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2101352118
https://phys.org/news/2021-08-cellular-motion-wound.html?utm_source...
part 2
Sep 1, 2021
Dr. Krishna Kumari Challa
Cadherins need calcium ions to complete their connections, so Shim grew the cells with different amounts of calcium and measured their response to electrical stimulation. She saw that the less calcium the cells had, the more fluid they became and the quicker they moved. "It goes really fast.
Calcium has many effects on living tissues, however, so Shim had to confirm that the handshakes were to blame for the slow movement. She grew cells with an antibody that attaches to cadherins. With blocked handshakes, these cells moved more quickly.
After working out the ground rules of cell adhesiveness, the researchers developed a solution to their sticky cell problem. Shim grew a layer of skin cells in a high calcium solution so they made their normal connections. Then she treated the cells with a chemical that grabs up calcium ions to break up the cellular handshakes. When Shim lowered the calcium level and applied the electric field, the cells moved on command. Finally, she restored the high calcium level to reinstate the handshakes, resulting in a healthy and cohesive layer of skin cells.
To demonstrate that this approach has the potential to accelerate healing, Shim performed the above experiment using an electrobioreactor developed in the Cohen lab that mimics the closing of a wound. Unlike other models of electrotaxis where the electric field moves cells in one direction, their new system exposes cells to an electric field focused on the center of the injury. Shim showed that the stimulated tissues successfully came together while the unstimulated ones remained largely separate. Cohen's group described their electrobioreactor in a new paper in Biosensors and Bioelectronics.
part3
Sep 1, 2021
Dr. Krishna Kumari Challa
Model of SARS-CoV-2 dynamics reveals opportunity to prevent COVID-19 transmission
Scientists have simulated the transition of the SARS-CoV-2 spike protein structure from when it recognizes the host cell to when it gains entry, according to a study published today in eLife.
The research shows that a structure enabled by sugar molecules on the spike protein could be essential for cell entry and that disrupting this structure could be a strategy to halt virus transmission.An essential aspect of SARS-CoV-2's lifecycle is its ability to attach to host cells and transfer its genetic material. It achieves this through its spike protein, which is made up of three separate components—a transmembrane bundle that anchors the spike to the virus, and two S subunits (S1 and S2) on the exterior of the virus. To infect a human cell, the S1 subunit binds to a molecule on the surface of human cells called ACE2, and the S2 subunit detaches and fuses the viral and human cell membranes. Although this process is known, the exact order in which it occurs is as yet undiscovered. Yet, understanding the microsecond-scale and atomic-level movements of these protein structures could reveal potential targets for COVID-19 treatment.
Most of the current SARS-CoV-2 treatments and vaccines have focused on the ACE2 recognition step of virus invasion, but an alternative strategy is to target the structural change that allows the virus to fuse with the human host cell.
But probing these intermediate, transient structures experimentally is extremely difficult, and so researchers now used a computer simulation sufficiently simplified to investigate this large system but that maintains sufficient physical details to capture the dynamics of the S2 subunit as it transitions between pre-fusion and post-fusion shapes.
part 1
Sep 1, 2021
Dr. Krishna Kumari Challa
The team was particularly interested in the role of sugar molecules on the spike protein, which are called glycans. To see whether the number, type and position of glycans play a role in the membrane fusion stage of viral cell entry by mediating these intermediate spike formations, they performed thousands of simulations using an all-atom structure-based model. Such models allow prediction of the trajectory of atoms over time, taking into account steric forces—that is, how neighboring atoms affect the movement of others.
The simulations revealed that glycans form a "cage" that traps the "head" of the S2 subunit, causing it to pause in an intermediate form between when it detaches from the S1 subunit and when the viral and cell membranes are fused. When the glycans were not there, the S2 subunit spent much less time in this conformation.
The simulations also suggest that holding the S2 head in a particular position helps the S2 subunit recruit human host cells and fuse with their membranes, by allowing the extension of short proteins called fusion peptides from the virus. Indeed, glycosylation of S2 significantly increased the likelihood that a fusion peptide would extend to the host cell membrane, whereas when glycans were absent, there was only a marginal possibility that this would occur.
simulations indicate that glycans can induce a pause during the spike protein transition. This provides a critical opportunity for the fusion peptides to capture the host cell.
In the absence of glycans, the viral particle would likely fail to enter the host. Our study reveals how sugars can control infectivity, and it provides a foundation for experimentally investigating factors that influence the dynamics of this pervasive and deadly pathogen.
Esteban Dodero-Rojas et al, Sterically confined rearrangements of SARS-CoV-2 Spike protein control cell invasion, eLife (2021). DOI: 10.7554/eLife.70362
https://phys.org/news/2021-08-sars-cov-dynamics-reveals-opportunity...
part 2 **
Sep 1, 2021
Dr. Krishna Kumari Challa
Winners from the Wellcome Photography Prize 2021:
Fighting Infections
Sep 1, 2021
Dr. Krishna Kumari Challa
Scientists discover a rare, aggressive form of Alzheimer's that begins in the early 40s
A newly discovered gene mutation linked to early onset Alzheimer's disease has been discovered by an international team of scientists, who traced the DNA flaw through multiple members of a single family.
Alzheimer's has long been known as a mind-robbing disease that that wipes out memories and destroys one's sense of self. Most cases of arise sporadically, emerging after age of 65—transmuting one's golden years into a nightmare marked by an incurable brain disease.
Aside from Alzheimer's dementia that begins sporadically in old age, are insidious familial forms that begin years to decades earlier. Early onset refers Alzheimer's that begins before age 65.
Now, an international team of scientists—led by neurobiologists in Sweden—have identified an extraordinarily rare form of the disease that so far has been found only in one family. This form of Alzheimer's is aggressive, rapid and steals its victims' most productive years along their cognitive functions.
Researchers in Sweden have named this form of Alzheimer's—the Uppsala APP deletion—after the family that's endowed with this notorious DNA miscue. It invariably causes descent into dementia at a young age.
Affected individuals have an age at symptom onset in their early forties, and suffer from a rapidly progressing disease course.
Researchers found that the mutation accelerates the formation of brain-damaging protein plaques, known as amyloid beta, or more simply as Aβ. The gooey plaques destroy neurons and, as a result, annihilate the executive functions of the brain itself. Neuroscientists basically define executive functions as working memory, mental flexibility and self control.
María Pagnon de la Vega et al, The Uppsala APP deletion causes early onset autosomal dominant Alzheimer's disease by altering APP processing and increasing amyloid β fibril formation, Science Translational Medicine (2021). DOI: 10.1126/scitranslmed.abc6184
https://medicalxpress.com/news/2021-09-scientists-sweden-rare-aggre...
Sep 2, 2021
Dr. Krishna Kumari Challa
Do genetics control who our friends are? It seems so with mice
Have you ever met someone you instantly liked, or at other times, someone who you knew immediately that you did not want to be friends with, although you did not know why?
Some people speculated that "unconscious" part of the brain enables us to process information spontaneously, when, for example, meeting someone for the first time, interviewing someone for a job, or faced with making a decision quickly under stress.
Now, a new study from the University of Maryland School of Medicine (UMSOM) suggests that there may be a biological basis behind this instantaneous compatibility reaction. A team of researchers showed that variations of an enzyme found in a part of the brain that regulates mood and motivation seems to control which mice want to socially interact with other mice—with the genetically similar mice preferring each other.
These findings may indicate that similar factors could contribute to the social choices people make. Understanding what factors drive these social preferences may help us to better recognize what goes awry in diseases associated with social withdrawal, such as schizophrenia or autism, so that better therapies can be developed.
The study was published on July 28 in Molecular Psychiatry, a Nature publication.
But, let us wait till these results are reproduced several times before coming to a conclusion.
Abigail J. Smith et al, A genetic basis for friendship? Homophily for membrane-associated PDE11A-cAMP-CREB signaling in CA1 of hippocampus dictates mutual social preference in male and female mice, Molecular Psychiatry (2021). DOI: 10.1038/s41380-021-01237-4
https://medicalxpress.com/news/2021-09-genetics-friends-mice.html?u...
Sep 2, 2021
Dr. Krishna Kumari Challa
Hidden bacterial hairs power nature's 'electric grid'
A hair-like protein hidden inside bacteria serves as a sort of on-off switch for nature's "electric grid," a global web of bacteria-generated nanowires that permeates all oxygen-less soil and deep ocean beds, researchers report in the journal Nature.
The ground beneath our feet, the entire globe, is electrically wired. These previously hidden bacterial hairs are the molecular switch controlling the release of nanowires that make up nature's electrical grid.
Almost all living things breathe oxygen to get rid of excess electrons when converting nutrients into energy. Without access to oxygen, however, soil bacteria living deep under oceans or buried underground over billions of years have developed a way to respire by "breathing minerals," like snorkeling, through tiny protein filaments called nanowires.
Scientists had thought that the nanowires are made up of a protein called "pili" ("hair" in Latin) that many bacteria show on their surface. This work has reveal that this pili structure is made up of two proteins And instead of serving as nanowires themselves, pili remain hidden inside the bacteria and act like pistons, thrusting the nanowires into the environment. Previously nobody had suspected such a structure.
Just how these soil bacteria use nanowires to exhale electricity, however, has remained a mystery. Now that mystery has been solved.
Understanding how bacteria create nanowires will allow scientists to tailor bacteria to perform a host of functions—from combatting pathogenic infections or biohazard waste to creating living electrical circuits, the authors say. It will also assist scientists seeking to use bacteria to generate electricity, create biofuels, and even develop self-repairing electronics.
Structure of Geobacter pili reveals secretory rather than nanowire behaviour, Nature (2021). DOI: 10.1038/s41586-021-03857-w , www.nature.com/articles/s41586-021-03857-w
https://phys.org/news/2021-09-hidden-bacterial-hairs-power-nature.h...
Sep 2, 2021
Dr. Krishna Kumari Challa
Ultrasonic social distancing
Social distancing has been a critical component of the world's response to the COVID-19 pandemic. The idea being that keeping physical apart from other people will reduce the risk of a person spreading the respiratory virus to someone else. It is just one component of our response, which also includes wearing face coverings, frequent hand sanitisation, and obtaining a vaccine against the virus.
New research in the International Journal of Sensor Networks discusses the potential of ultrasonic sensors to help people keep a safe distance from others when social distancing is deemed necessary in a pandemic situation.
Mohit Ghai and Ruchi Gupta of the Department of Electrical and Electronics Engineering at ADGITM, IP University in Delhi, India, describe a small, portable sensor-alarm device based on an Arduino system. Arduino is an open-source hardware and software system that can be used to quickly build single-board microcontrollers and microcontroller kits with a variety of inexpensive applications. There is scope to add Wi-Fi capability and other networking functionality to a device too.
The team's Arduino device has an ultrasonic sensor that continuously probes the space around a person and is triggered when another person enters one's personal space within a pre-determined threshold distance set according to social distancing rules. The system is not dissimilar to the parking sensors with which many vehicles are fitted and so could give a timely indication to the user that they have moved too close to another person unwittingly or alert them when another person moves nearer to them in a shopping queue or other setting, for instance.
Given how often people misjudge distances between themselves and others especially in busy environments, a portable alarm system of this sort could be a boon to those hoping to ensure social distancing is maintained to help reduce the risk of spreading infection.
Mohit Ghai et al, Ultrasonic sensor based social distancing device, International Journal of Sensor Networks (2021). DOI: 10.1504/IJSNET.2021.117227
https://techxplore.com/news/2021-09-ultrasonic-social-distancing.ht...
Sep 2, 2021
Dr. Krishna Kumari Challa
Scientific breakthrough in the battle against cancer: First 3D printing of glioblastoma cancer tumor
Sep 2, 2021
Dr. Krishna Kumari Challa
Biologists Just Got Closer to The DNA Secrets That Stop Species From Interbreeding
We think of DNA as the vitally important molecules that carry genetic instructions for most living things, including ourselves. But not all DNA actually codes proteins; now, we're finding more and more functions involving the non-coding DNA scientists used to think of as 'junk'.
A new study suggests that satellite DNA – a type of non-coding DNA arranged in long, repetitive, apparently nonsensical strings of genetic material – may be the reason why different species can't successfully breed with each other.
It appears that satellite DNA plays an essential role in keeping all of a cell's individual chromosomes together in a single nucleus, through the work of cellular proteins.
According to biologists Madhav Jagannathan and Yukiko Yamashita who authored the new study, that important role is managed differently in each species, leading to genetic incompatibility. The clash of the different strategies between species may be what causes chromosomes to scatter outside of the nucleus, at least in part, preventing reproduction.
"We propose a unifying framework that explains how the widely observed satellite DNA divergence between closely related species can cause reproductive isolation," they write in their paper.
This "satellite DNA divergence" has been well established in previous research, leading to suspicions about its role in speciation. In the case of the chimpanzee genome and the human genome, for example, the protein-coding DNA is almost identical, while the 'junk' DNA is almost entirely different.
https://academic.oup.com/mbe/advance-article/doi/10.1093/molbev/msa...
https://www.sciencealert.com/junk-dna-could-be-why-different-specie...
Sep 2, 2021
Dr. Krishna Kumari Challa
Study explores the influence of the X-chromosome on brain anatomy
Past neuroscience research suggests that common differences in people's genetic profiles can explain a significant proportion of variations in people's brain anatomy. In more specific terms, they found that neuroanatomical variation is partly explained by genetic variation.
Scientists have hypothesized that the X-chromosome has a particularly crucial influence on the brain, as it is known to be associated with the expression of many genes. In addition, several types of intellectual disabilities have been found to be related with mutations of genes on the X chromosome.
All existing studies investigating the role of genetics on brain anatomy excluded the X-chromosome, which accounts for about 5% of our genomes. it would be important to address this gap because—beyond the basic need to complete the missing analysis—there were lot of existing hints that the X-chromosome might actually have a special capacity to explain variation in brain anatomy.
So if a common genetic variation explains 30% of variation in total brain volume, then a chromosome which represents 10% of the genome would explain 3% of variation in total brain volume.
The X-chromosome consists of approximately 5% of the total genome. Taking this into consideration, researchers calculated the proportion of anatomical variation that could be explained by the X-chromosome. They found that given its known size and the percentage of the human genome it represents, the proportion they calculated differed significantly from the expected proportion.
The main take-aways from our studies are that the X-chromosome does indeed 'punch above its weight' in its capacity to explain differences in brain anatomy and that this phenomenon seems to be concentrated in particular brain systems important for complex thinking, decision making and action.
In terms of practical implications— this finding tells us that we really do need to put an end to exclusion of the X-chromosome from genetic analyses of the brain and related traits such as cognition and behavior.
The findings gathered by this team of researchers significantly enrich the current understanding of the X-chromosome's role in human neurodevelopment.
X-chromosome influences on neuroanatomical variation in humans. Nature Neuroscience(2021). DOI: 10.1038/s41593-021-00890-w
https://medicalxpress.com/news/2021-09-explores-x-chromosome-brain-...
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Sep 3, 2021
Dr. Krishna Kumari Challa
A gecko-inspired robot's crash-landing correction
Sep 3, 2021
Dr. Krishna Kumari Challa
Birds and mammals evolve faster if their home is rising
The rise and fall of Earth's land surface over the last three million years shaped the evolution of birds and mammals, a new study has found, with new species evolving at higher rates where the land has risen most.
Researchers at the University of Cambridge have combined reconstructions of the Earth's changing surface elevations over the past three million years with data on climate change over this timeframe, and with bird and mammal species' locations. Their results reveal how species evolved into new ones as land elevation changed—and disentangle the effects of elevation from the effects of climate.
The study found that the effect of elevation increase is greater
than that of historical climate change, and of present-day elevation and temperature, in driving the formation of new species – 'or speciation'.
In contrast to areas where land elevation is increasing, elevation loss was not found to be an important predictor of where speciation happens. Instead, present-day temperature is a better indicator of speciation in these areas.
The results are published today in the journal Nature Ecology and Evolution.
Global topographic uplift has elevated speciation in mammals and birds over the last 3 million years, Nature Ecology and Evolution (2021). DOI: 10.1038/s41559-021-01545-6 , www.nature.com/articles/s41559-021-01545-6
https://phys.org/news/2021-09-birds-mammals-evolve-faster-home.html...
Sep 3, 2021
Dr. Krishna Kumari Challa
Nano 'camera' made using molecular glue allows real-time monitoring of chemical reactions
Researchers have made a tiny camera, held together with 'molecular glue' that allows them to observe chemical reactions in real time.
The device, made by a team from the University of Cambridge, combines tiny semiconductor nanocrystals called quantum dots and gold nanoparticles using molecular glue called cucurbituril (CB). When added to water with the molecule to be studied, the components self-assemble in seconds into a stable, powerful tool that allows the real-time monitoring of chemical reactions.
The camera harvests light within the semiconductors, inducing electron transfer processes like those that occur in photosynthesis, which can be monitored using incorporated gold nanoparticle sensors and spectroscopic techniques. They were able to use the camera to observe chemical species which had been previously theorized but not directly observed.
The platform could be used to study a wide range of molecules for a variety of potential applications, such as the improvement of photocatalysis and photovoltaics for renewable energy. The results are reported in the journal Nature Nanotechnology.
Földes, T. et al, Nanoparticle surfactants for kinetically arrested photoactive assemblies to track light-induced electron transfer, Nat. Nanotechnol. (2021). DOI: 10.1038/s41565-021-00949-6 , www.nature.com/articles/s41565-021-00949-6
https://phys.org/news/2021-09-nano-camera-molecular-real-time-chemi...
Sep 3, 2021
Dr. Krishna Kumari Challa
Decaying forest wood releases 10.9 billion tons of carbon yearly, which will increase with climate change
If you've wandered through a forest, you've probably dodged dead, rotting branches or stumps scattered on the ground. This is "deadwood," and it plays several vital roles in forest ecosystems.
It provides habitat for small mammals, birds, amphibians and insects. And as deadwood decomposes it contributes to the ecosystem's cycle of nutrients, which is important for plant growth.
But there's another important role we have little understanding of on a global scale: the carbon deadwood releases as it decomposes, with part of it going into the soil and part into the atmosphere. Insects, such as termites and wood borers, can accelerate this process.
The world's deadwood currently stores 73 billion tons of carbon. Our new research in Nature has, for the first time, calculated that 10.9 billion tons of this (around 15%) is released into the atmosphere and soil each year—a little more than the world's emissions from burning fossil fuels.
But this amount can change depending on insect activity, and will likely increase under climate change. It's vital deadwood is considered explicitly in all future climate change projections.
Sebastian Seibold et al, The contribution of insects to global forest deadwood decomposition, Nature (2021). DOI: 10.1038/s41586-021-03740-8
https://phys.org/news/2021-09-forest-wood-billion-tons-carbon.html?...
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Sep 3, 2021
Dr. Krishna Kumari Challa
How harmful is methane?
Methane contributes to global warming; it is therefore a greenhouse gas. Of all the methane produced in some developed countries, 70% comes from livestock farming. A substantial percentage. But how harmful is it? Because, unlike other greenhouse gasses, methane breaks down relatively quickly in the atmosphere.
Greenhouse gasses are important. They form a blanket around the earth. Without greenhouse gasses, it would be unbearably cold on earth. The problem with the greenhouses gasses is that we too much of them. The blanket becomes so thick, that the earth's temperature rises. This causes periods of drought and in other places too much precipitation, the polar caps melt, and so on.
there are three greenhouse gasses: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Roughly speaking, you can say that all three are created during the breakdown or combustion of organic substances. CO2 (and NOx) are mainly created through the combustion of diesel, lignite or gasoline. Not only in transport and traffic, but also in production processes. From the concrete in your house to the staples in your furniture, almost everything in our lives produces CO2 during its production.
Methane is released during the breakdown of organic substances. For example, in the gastrointestinal tract of animals. Ruminants (cows, goats, sheep) in particular produce a lot of methane. Methane is also 34 times more powerful than carbon dioxide. So, the earth warms up extra fast when there is more methane in the atmosphere. N2O is created in processes where nitrogen compounds play a role: in manure storage and manure application."
part 1
Sep 3, 2021
Dr. Krishna Kumari Challa
CO2 stays in the atmosphere for a very, very long time. Many thousands of years. So that greenhouse gas accumulates, and the 'blanket' around the earth thickens. The unique thing about methane is that it halves in the atmosphere in just over 8 years. The other half becomes CO2. So if you emit 100 kilos of methane today, in 8.5 years there will be 50 kilos left, and after another 8.5 years only 25 kilos, and so on," Vellinga explains. "That CO2 has gone through what is known as the short carbon cycle: it was converted by grass, corn, etc. into plant material, which the cow converts back into CO2 and CH4. And that CH4 becomes CO2 again pretty quickly. Nothing to worry about, you might say."
"But be careful not to make the problem too small. Before you know it, it seems as if there is nothing wrong with methane. On the contrary. As long as methane is in the atmosphere, it contributes very strongly to warming. Over the lifetime of methane, this is as much as 80 to 100 times more than CO2.
But the advantage is that it disappears quickly. Reducing methane emissions can cause the concentration of methane in the atmosphere to drop and therefore even reduce the greenhouse effect. When reducing CO2, the current greenhouse effect remains the same and only does not increase. So reducing methane is more effective than reducing CO2. But it has to be done both ways."
https://phys.org/news/2021-09-fact-methane.html?utm_source=nwletter...
Part 2
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Sep 3, 2021
Dr. Krishna Kumari Challa
How Do Ants Tunnel So Well?
Sep 3, 2021
Dr. Krishna Kumari Challa
Drug cocktail reduces aging-associated disc degeneration
Chronic back pain affects millions of adults in the world. Degeneration of the discs that cushion and support vertebrae, a common occurrence of aging, is a major contributor to low back pain. Although a widespread condition, few treatments are available.
With age, every tissue in the body accumulates senescent cells. Senescent cells secrete destructive enzymes and inflammatory proteins that affect nearby healthy cells. Senolytic drugs remove these deteriorating cells, leaving room for new cells to replace them. The idea is that removing senescent cells from a tissue will improve the tissue's function.
New research has shown that treating mice with a drug cocktail that removes aging cells reduces disc degeneration. The findings, reported in Nature Communications on September 3rd, show how a novel approach to preventing age-related disc degeneration may pave the way for treating chronic back pain.
The findings show that senolytic drugs—ones already approved for use in clinical trials—can mitigate disc degeneration that occurs with aging.
Just because the drugs work in one tissue doesn't mean they will also work in another. Every tissue is different and should be treated differently.
Young and middle-aged mice given the senolytic cocktail showed less disc degeneration and fewer senescent cells by the time they reached an advanced age compared to mice given a placebo.
"Long-term treatment with senolytic drugs Dasatinib and Quercetin ameliorates age-dependent intervertebral disc degeneration in mice." Nature Communications (2021) , DOI: 10.1038/s41467-021-25453-2
https://medicalxpress.com/news/2021-09-drug-cocktail-aging-associat...
Sep 4, 2021
Dr. Krishna Kumari Challa
The first cells might have used temperature to divide
A simple mechanism could underlie the growth and self-replication of protocells—putative ancestors of modern living cells—suggests a study publishing September 3 in Biophysical Journal. Protocells are vesicles bounded by a membrane bilayer and are potentially similar to the first unicellular common ancestor (FUCA). On the basis of relatively simple mathematical principles, the proposed model suggests that the main force driving protocell growth and reproduction is the temperature difference that occurs between the inside and outside of the cylindrical protocell as a result of inner chemical activity.
The purpose of this study was to identify the main forces driving cell division. This is important because cancer is characterized by uncontrolled cell division. This is also important to understand the origin of life.
The splitting of a cell to form two daughter cells requires the synchronization of numerous biochemical and mechanical processes involving cytoskeletal structures inside the cell. But in the history of life, such complex structures are a high-tech luxury and must have appeared much later than the ability to split. Protocells must have used a simple splitting mechanism to ensure their reproduction, before the appearance of genes, RNA, enzymes, and all the complex organelles present today, even in the most rudimentary forms of autonomous life.
In the new study, researchers proposed a model based on the idea that the early forms of life were simple vesicles containing a particular network of chemical reactions—a precursor of modern cellular metabolism. The main hypothesis is that molecules composing the membrane bilayer are synthesized inside the protocell through globally exothermic, or energy-releasing, chemical reactions.
The slow increase of the inner temperature forces the hottest molecules to move from the inner leaflet to the outer leaflet of the bilayer. This asymmetric movement makes the outer leaflet grow faster than the inner leaflet. This differential growth increases the mean curvature and amplifies any local shrinking of the protocell until it splits in two. The cut occurs near the hottest zone, around the middle.
The scenario described can be viewed as the ancestor of mitosis. Having no biological archives as old as 4 billion years, we don't know exactly what FUCA contained, but it was probably a vesicle bounded by a lipid bilayer encapsulating some exothermic chemical reactions.
Although purely theoretical, the model could be tested experimentally.
Biophysical Journal, Attal and Schwartz: "Thermally driven fission of protocells" www.cell.com/biophysical-journ … 0006-3495(21)00686-X , DOI: 10.1016/j.bpj.2021.08.020
https://phys.org/news/2021-09-cells-temperature.html?utm_source=nwl...
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Sep 4, 2021
Dr. Krishna Kumari Challa
Unified theory explains how materials transform from solids to liquids
A new study unveils a unified mathematical expression that defines how soft-yet-rigid materials transition from a solid into a liquid flow when they exceed their specific stress threshold.
This study has shown that these physical states—solid and liquid—can exist together in the same material, and we can explain it using one mathematical expression.
To develop this model, the team performed numerous studies that subjected a variety of different soft materials to stress while measuring the individual solidlike and liquidlike strain responses using a device called a rheometer.
The researchers were able to observe a material's behavior and see a continuous transition between the solid and liquid states and were able to resolve two distinct behaviors that reflect energy dissipation via solid and fluid mechanisms.
Krutarth Kamani et al, Unification of the Rheological Physics of Yield Stress Fluids, Physical Review Letters (2021). DOI: 10.1103/PhysRevLett.126.218002
https://phys.org/news/2021-09-theory-materials-solids-liquids.html?...
Sep 4, 2021
Dr. Krishna Kumari Challa
Fish eyes grown in a petri dish from embryonic stem cells
A research team has demonstrated that complex retinal tissue can be cultured in a Petri dish from embryonic stem cells of bony fish. Until now, stem cells from mammals, including humans, have been used in organoid research. For the first time, researchers have demonstrated that stem cells from medaka and zebrafish can also form highly organized neural structures under controlled laboratory conditions. Among other things, the researchers expect to gain new insights into the basic mechanisms of retinal development.
Organoids are bits of tissue that are grown from stem cells and resemble actual organs. They are used in basic research to gain new information on cell organization and organ development, to investigate the origin of disease, and to develop and test new medications. The major advantage of fish organoids is that they are highly reproducible, unlike organoids from mammalian stem cells. They develop reliably and very quickly and enable a direct comparison with living embryos that in fish grow outside of the womb.
Researchers are now able to manipulate the molecular and genetic mechanisms of retina formation.
Researchers used pluripotent stem cells from medaka and zebrafish embryos. Such cells have not yet differentiated and can potentially develop into many different cell types. All the cells taken from a single embryo independently aggregated into one large retina within 24 hours. In a matter of a few days, it then formed layers of different cell types that are also found in the fish eye, including photoreceptor cells, bipolar cells, amacrine cells, and ganglion cells. The growth process proved to be incredibly efficient. Hundreds of small retina organoids could be generated within a day. The high throughput allowed the researchers to precisely isolate the conditions in which structures resembling a head with two eyes, including both brain and retina, are formed.
Lucie Zilova et al, Fish primary embryonic pluripotent cells assemble into retinal tissue mirroring in vivo early eye development, eLife (2021). DOI: 10.7554/eLife.66998
https://phys.org/news/2021-09-fish-eyes-grown-petri-dish.html?utm_s...
Sep 4, 2021
Dr. Krishna Kumari Challa
Coronavirus epidemics first hit more than 21,000 years ago
Sarbecoviruses have crossed into humans twice in the last decade, leading to the deadly SARS-CoV-1 outbreak in 2002-04 and the current COVID-19 pandemic, caused by the SARS-CoV-2 virus. A new Oxford University study, published today, shows that the most recent common ancestor of these viruses existed more than 21,000 years ago, nearly 30 times older than previous estimates.
Despite having a very rapid rate of evolution over short timescales, to survive, viruses must remain highly adapted to their hosts—this imposes severe restrictions on their freedom to accumulate mutations without reducing their fitness. This causes the apparent rate of evolution of viruses to slow down over time. The new research, for the first time, successfully recreates the patterns of this observed rate decay in viruses.
The study also demonstrates that while existing evolutionary models have often failed to measure the divergence between virus species over periods—from a few hundred to a few thousands of years—the evolutionary framework developed in this study will enable the reliable estimation of virus divergence across vast timescales, potentially over the entire course of animal and plant evolution.
The new model enables us to not only reconstruct the evolutionary history of viruses related to SARS-CoV-2, but also a much wider range of RNA and DNA viruses during more remote periods in the past.
Mahan Ghafari et al, A mechanistic evolutionary model explains the time-dependent pattern of substitution rates in viruses, Current Biology (2021). DOI: 10.1016/j.cub.2021.08.020
https://phys.org/news/2021-09-coronavirus-epidemics-years.html?utm_...
Sep 4, 2021
Dr. Krishna Kumari Challa
Hormones May Contribute to Asymmetrical Effects of Brain Injury
Researchers studying rats claim to have found a novel connection between damage on one side of the brain and problems with the posture or movement of limbs on the opposite side of the body.
Injury to one side of the brain can cause abnormalities in posture or movement on the opposite side of the body. These effects, which are sometimes seen in people who have suffered a stroke or head trauma, have typically been attributed to neural pathways that link the right side of the brain to spinal cord neurons controlling muscles on the left side of the body, and vice versa.
But in a new study on rats that had their spinal cords severed, researchers claim to have discovered another, parallel pathway that triggers opposite-side effects following brain injury and might instead operate via hormones circulating in the blood.
If similar mechanisms operate in humans, it’s conceivable that drugs blocking receptors for particular hormones could help treat some of the physical effects of brain injury
https://elifesciences.org/articles/65247
https://www.the-scientist.com/news-opinion/hormones-may-contribute-...
Sep 4, 2021
Dr. Krishna Kumari Challa
“Mystery Fever” Claims the Lives of Dozens of Indian Children
So far, more than 50 people have died of a febrile illness, though the cause isn’t clear.
In addition to the ongoing COVID-19 pandemic and an uptick of malaria cases across the country, an unknown disease has killed more than 50 people in the state of Uttar Pradesh, India in the last week; most were children. All of the patients tested negative for COVID-19, and India Today reports it is likely that scrub typhus is to blame, though other possibilities, such as dengue, have not been ruled out.
The Hindustan Times reports, and monsoon season has brought a greater number of mosquito-borne illnesses. Now, many regions in the state are reporting illness and death due to a mystery fever.
Water-logging, and lack of sanitation and hygiene are the reasons behind the disease spread. The patients, especially children, in hospitals are dying very quickly.
According to multiple news outlets, the hundreds of people hospitalized by the illness have experienced fever, headaches, joint pain, nausea, rashes, and dehydration. A drop in platelet count has also been observed in many fatal cases. Though many of these symptoms can occur in severe dengue cases, The Hindustan Times and others report that the likely culprit is a bacterial disease called scrub typhus.
Scrub typhus can occur after a person is bitten by chiggers infected with Orientia tsutsugamushi bacteria. According to the BBC, these mites live on plants that flourish after the monsoon rains, and they can hitchhike into people’s homes on firewood. The symptoms of O. tsutsugamushi infection largely overlap with what has been seen in the patients.
According to the US Center for Disease Control and Prevention (CDC), there are no vaccinations for scrub typhus and it should be treated with the antibiotic doxycycline. The agency recommends covering exposed skin to prevent chigger bites.
https://www.the-scientist.com/news-opinion/mystery-fever-claims-the...
Sep 4, 2021
Dr. Krishna Kumari Challa
Biomedical Innovations from Women Less Likely to be Adopted: Study
An analysis of scientists’ networks finds discrepancies in the diffusion of novel ideas through communities.
Sep 4, 2021
Dr. Krishna Kumari Challa
Why words become harder to remember as we get older
As we get older, we find it increasingly difficult to have the right words ready at the right moment, even though our vocabulary actually grows continuously over the course of our lives. Until now, it was unclear why this is. Researchers have now found out: It is the networks in the brain that change their communication over time. This makes them more inefficient.
The researchers investigated these connections with the help of two groups - younger study participants between the ages of 20 and 35 and older ones between the ages of 60 and 70. Both groups were asked to name words in the MRI scanner that belong to certain categories, including animals, metals or vehicles.
It became clear that both age groups were good at finding words. However, the younger ones were somewhat faster. The reason for this could be the different brain activities. For one thing, not only were the language areas themselves more active in the younger ones. They also showed a more intensive exchange within two decisive networks: the network for semantic memory, in which factual knowledge is stored, and the executive network, which is responsible for general functions such as attention and memory.
The reverse was true for older people. Here, executive areas showed stronger activity, indicating that the task was more difficult for these individuals overall. In addition, the exchange within the crucial networks was less effective than in the younger people. The older group was most likely to benefit from inter-network exchange, but this is associated with losses. Communication within neuronal networks is more efficient and thus faster than between them.
Why these activity patterns shift with age has not yet been fully explained. One theory, says Martin, is that as people age, they rely more on the linguistic knowledge they have, so exchanges between networks come into focus, while younger people rely more on their fast working memory and cognitive control processes. On the structural level, the loss of grey matter in the brain could also play a role, which is compensated for by the exchange between networks.
“Age-Dependent Contribution of Domain-General Networks to Semantic C...” by Sandra Martin et al. Cerebral Cortex
https://researchnews.cc/news/8725/Why-words-become-harder-to-rememb...
Sep 5, 2021
Dr. Krishna Kumari Challa
Robo Pill
Sep 6, 2021
Dr. Krishna Kumari Challa
Sport science: How do swimmers control their front crawl swimming velocity?
A research team has reviewed the hydrodynamics literature related to swimming. They identified certain biomechanical aspects, including the relationship between velocity and drag forces, that are not completely understood. This work may help direct future research that could improve the performance of competitive swimmers.
The recent Tokyo Olympics provided impressive feats of speed in the pool, with elite athletes setting many new Olympic and World records. What viewers might not realize, however, is the complexity of the science underlying the sometimes split-second difference between winning a gold medal and going home empty-handed. Biomechanics, the study of motion of the body, and hydrodynamics, the area of physics dealing with fluid flows, contain many questions that remain poorly understood—and swimming fits right at the intersection of these topics. For swimmers who participate in races, even a tiny advance in knowledge can led to a competitive edge.
Now, a team of researchers has drawn together research on front crawl swimming biomechanics, focusing on propulsive and resistive forces at different swimming velocities, to form a more complete picture of the relationships between the critical variables. New knowledge of swimming energetics and fluid mechanics has improved our understanding of factors that determine swimming performance.
One of the most important relationships to understand is how resistive forces, like drag when moving through the water, depend on the speed of the swimmer. The researchers looked at recent studies that indicated the resistive force increases in proportion to the cube of the velocity. To compensate, swimmers may try to increase their stroke frequency. However, this has limitations. Researchers inferred from experimental and simulation studies that there is a maximum frequency beyond which swimmers cannot further increase swimming velocity due to a change in the angle of attack of the hand that reduces its propulsive force. The different balance of forces at different swimming speeds also means that optimal technique may differ between long-distance and short-distance swimming.
The team also identified conflicting evidence over the effectiveness of kicking for increasing the speed of high-velocity front crawl. This indicates an opportunity to further optimize competitive swimming technique if future research can further unpack the relevant hydrodynamic factors.
The researchers found that certain simplified models of swimming often break down when trying to model more realistic conditions. For example, swimmers are not simply 'pushing' or 'pulling' the water to increase their velocity, as some textbooks frame it. This is because the increase in the negative pressure acting on the dorsal side of the hand is crucial for increasing propulsion. Therefore, teaching the proper technique is important, even for phases considered to be non-propulsive.
Hideki Takagi et al, How do swimmers control their front crawl swimming velocity? Current knowledge and gaps from hydrodynamic perspectives, Sports Biomechanics (2021). DOI: 10.1080/14763141.2021.1959946
https://phys.org/news/2021-09-swimmers-front-velocity.html?utm_sour...
Sep 7, 2021
Dr. Krishna Kumari Challa
Cavendish Gravity Experiment
A qualitative demonstration of universal gravitation using a torsion balance.
Sep 8, 2021
Dr. Krishna Kumari Challa
Fridge-free COVID-19 vaccines grown in plants and bacteria
Nanoengineers have developed COVID-19 vaccine candidates that can take the heat. Their key ingredients? Viruses from plants or bacteria.
The new fridge-free COVID-19 vaccines are still in the early stage of development. In mice, the vaccine candidates triggered high production of neutralizing antibodies against SARS-CoV-2, the virus that causes COVID-19. If they prove to be safe and effective in people, the vaccines could be a big game changer for global distribution efforts, including those in rural areas or resource-poor communities.
What's exciting about this vaccine technology is that is thermally stable, so it could easily reach places where setting up ultra-low temperature freezers, or having trucks drive around with these freezers, is not going to be possible.
The researchers created two COVID-19 vaccine candidates. One is made from a plant virus, called cowpea mosaic virus. The other is made from a bacterial virus, or bacteriophage, called Q beta.
Both vaccines were made using similar recipes. The researchers used cowpea plants and E. coli bacteria to grow millions of copies of the plant virus and bacteriophage, respectively, in the form of ball-shaped nanoparticles. The researchers harvested these nanoparticles and then attached a small piece of the SARS-CoV-2 spike protein to the surface. The finished products look like an infectious virus so the immune system can recognize them, but they are not infectious in animals and humans. The small piece of the spike protein attached to the surface is what stimulates the body to generate an immune response against the coronavirus.
The researchers note several advantages of using plant viruses and bacteriophages to make their vaccines. For one, they can be easy and inexpensive to produce at large scales.
Another big advantage is that the plant virus and bacteriophage nanoparticles are extremely stable at high temperatures. As a result, the vaccines can be stored and shipped without needing to be kept cold.
Trivalent subunit vaccine candidates for COVID-19 and their delivery devices, Journal of the American Chemical Society (2021). DOI: 10.1021/jacs.1c06600
https://phys.org/news/2021-09-fridge-free-covid-vaccines-grown-bact...
Sep 8, 2021
Dr. Krishna Kumari Challa
Sep 8, 2021
Dr. Krishna Kumari Challa
Why are planets round?
The Earth and all planets are round because when the planets formed, they were composed of molten material – essentially very hot liquid. Since gravity always points toward the center of a mass, it squeezed the stuff the Earth is made of equally in all directions and formed a ball. When the Earth cooled down and became a solid, it was a round ball. If the Earth didn’t spin, then it would have been a perfectly round planet. Scientists call something that is perfectly round in all directions a “sphere.”
The gas cloud that the Earth was made from was slowly rotating in one direction around an axis. The top and bottom of this axis are the north and south poles of Earth.
If you ever played on a merry-go-round, you know that the spinning merry-go-round tends to throw you off. The faster it spins, the harder it is to stay on. This tendency to be flung off is called centrifugal force and pushes the mass on the equator outward. This makes the planet bulge at the equator.
The faster the spin, the more unround it becomes. Then, when it cools and hardens, it retains that shape. If a molten planet starts off spinning faster, it would be less round and have a bigger bulge.
The planet Saturn is very oblate – non-spherical – because it rotates very fast. Because of gravity, all planets are round, and because they rotate at different rates, some have fatter equators than their poles. So the shape of the planet and the speed and direction that it rotates depends on the initial condition of the material out of which it forms.
https://theconversation.com/why-are-planets-round-164903?utm_medium...
Sep 8, 2021
Dr. Krishna Kumari Challa
New Mathematical Solutions to An Old Problem in Astronomy
Sep 8, 2021
Dr. Krishna Kumari Challa
Hundreds of Medical Journals Just United Together to Issue a Brutally Frank Warning
Global warming is already affecting people's health so much that emergency action on climate change cannot be put on hold while the world deals with the COVID-19 pandemic, medical journals across the globe warned on Monday.
Health is already being harmed by global temperature increases and the destruction of the natural world," read an editorial published in more than 220 leading journals ahead of the COP26 climate summit in November.
Since the pre-industrial era, temperatures have risen around 1.1 degrees Celsius.
The editorial, written by the editors-in-chief of over a dozen journals including the Lancet, the East African Medical Journal, Brazil's Revista de Saude Publica and the International Nursing Review, said this had caused a plethora of health problems.
"In the past 20 years, heat-related mortality among people older than 65 years has increased by more than 50 percent," it read.
"Higher temperatures have brought increased dehydration and renal function loss, dermatological malignancies, tropical infections, adverse mental health outcomes, pregnancy complications, allergies, and cardiovascular and pulmonary morbidity and mortality."
It also pointed to the decline in agricultural production, "hampering efforts to reduce undernutrition".
These effects, which hit those most vulnerable like minorities, children, and poorer communities hardest, are just the beginning, it warned.
https://www.bmj.com/content/374/bmj.n1734
Sep 8, 2021
Dr. Krishna Kumari Challa
NASA Testing Electric 'Air Taxi' Prototype Designed to Carry Passengers in The Sky
NASA is commonly thought of as America's space agency, but its name also emphasizes another research area. The National Aeronautics and Space Administration is also America's civilian aerospace research organization.
Electric Vertical Take-Off and Landing Aircraft
Sep 8, 2021
Dr. Krishna Kumari Challa
The squid and its giant nerve fibre Part 1
Sep 8, 2021
Dr. Krishna Kumari Challa
Sep 8, 2021
Dr. Krishna Kumari Challa
Scientists create artificial cells that mimic living cells' ability to capture, process, and expel material
Researchers have developed artificial cell-like structures using inorganic matter that autonomously ingest, process, and push out material—recreating an essential function of living cells.
Their article, published in Nature, provides a blueprint for creating "cell mimics," with potential applications ranging from drug delivery to environmental science.
A fundamental function of living cells is their ability to harvest energy from the environment to pump molecules in and out of their systems. When energy is used to move these molecules from areas of lower concentration to areas of higher concentration, the process is called active transport. Active transport allows cells to take in necessary molecules like glucose or amino acids, store energy, and extract waste.
For decades, researchers have been working to create artificial cells—engineered microscopic structures that emulate the features and behavior of biological cells. But these cell mimics tend to lack the ability to perform complex cellular processes like active transport.
In the Nature study, researchers describe a new, fully synthetic cell mimic that is one step closer to replicating the function of living cells. When deployed in mixtures of different particles, the cell mimics can perform active transport tasks by autonomously capturing, concentrating, storing, and delivering microscopic cargo. These artificial cells are fabricated using minimal ingredients and borrow no materials from biology.
To design the cell mimics, the researchers created a spherical membrane the size of a red blood cell using a polymer, a stand-in for the cellular membrane that controls what goes in and out of a cell. They pierced a microscopic hole into the spherical membrane creating a nano-channel through which matter can be exchanged, imitating a cell's protein channel.
But in order to perform the tasks required for active transport, the cell mimics needed a mechanism to power the cell-like structure to pull in and expel material. In a living cell, mitochondria and ATP provide the necessary energy for active transport. In the cell mimic, the researchers added a chemically reactive component inside the nano-channel that, when activated by light, acts as a pump. When light hits the pump, it triggers a chemical reaction, turning the pump into a tiny vacuum and pulling cargo into the membrane. When the pump is switched off, the cargo is trapped and processed inside the cell mimic. And when the chemical reaction is reversed, the cargo is pushed out on demand.
Transmembrane transport in inorganic colloidal cell mimics, Nature (2021). DOI: 10.1038/s41586-021-03774-y , www.nature.com/articles/s41586-021-03774-y
https://phys.org/news/2021-09-scientists-artificial-cells-mimic-abi...
Sep 9, 2021
Dr. Krishna Kumari Challa
Common medications accumulate in gut bacteria, which may reduce drug effectiveness and alter the gut microbiome
Common medications can accumulate in gut bacteria, a new study has found, altering bacterial function and potentially reducing the effectiveness of the drug. These interactions—seen for a variety of medications, such as depression, diabetes, and asthma drugs—could help researchers to better understand individual differences in drug effectiveness and side-effects, according to the study published in Nature.
It is known that bacteria can chemically modify some drugs, a process known as biotransformation. This study is the first to show that certain species of gut bacteria accumulate human drugs.
This could change the effectiveness of the drug both directly, as the accumulation could reduce the availability of the drug to the body, and indirectly, as altered bacterial function and composition could be linked to side-effects.
The human gut naturally contains communities of hundreds of different species of bacteria, which are important in health and disease, called the gut microbiome. The composition of bacterial species varies significantly between people and has previously been shown to be associated with a wide range of conditions including obesity, immune response, and mental health.
In this study, the researchers grew 25 common gut bacteria and studied how they interacted with 15 drugs that are taken orally. The drugs were chosen to represent a range of different types of common drugs, including antidepressant medications, which are known to affect individuals dissimilarly and cause side effects such as gut problems and weight gain.
The researchers tested how each of the 15 drugs interacted with the selected bacterial strains—a total of 375 bacteria-drug tests.
They found 70 interactions between the bacteria and the drugs studied—of which 29 had not been previously reported.
While earlier research has shown bacteria can chemically modify drugs, when the scientists studied these interactions further, they found that for 17 of the 29 new interactions, the drug accumulated within the bacteria without being modified.
Bioaccumulation of therapeutic drugs by human gut bacteria, Nature (2021). DOI: 10.1038/s41586-021-03891-8 , www.nature.com/articles/s41586-021-03891-8
https://medicalxpress.com/news/2021-09-common-medications-accumulat...
Sep 9, 2021
Dr. Krishna Kumari Challa
COVID, vaccine misinformation spread by hundreds of websites, analysis finds
More than 500 websites have promoted misinformation about the coronavirus—including debunked claims about vaccines, according to a firm that rates the credibility of websites.
NewsGuard announced Wednesday that, of the more than 6,700 websites it has analyzed, 519 have published false information about COVID-19. Some of the sites publish dubious health information or political conspiracy theories, while others were "created specifically to spread misinformation about COVID-19," the company says on its website.
It's become virtually impossible for people to tell the difference between a generally reliable site and an untrustworthy site. And that is why there is such a big business in publishing this information. They're all hoaxes that have gained traction, and we know that because we see them spreading from website to website. Some of the websites NewsGuard identified have become more popular online than trustworthy sources of information about COVID-19.
https://techxplore.com/news/2021-09-covid-vaccine-misinformation-hu...
Sep 9, 2021
Dr. Krishna Kumari Challa
Tea made with impure water tastes better
Chemical impurities in tap water can cause a thin film to form on the surface of a cup of tea, and these make it taste better than a drink made with pure water, according to researchers at ETH Zurich in Switzerland.
Pour yourself a cup of tea and leave it to cool slightly, and you may see a film on the surface that cracks like sea ice when you disturb the cup. There are many factors that affect the formation of this film, the researchers say, but the primary one is calcium carbonate in the water. When tap water contains a high amount of minerals such as calcium carbonate, it is called hard water.
“Tap water in many regions comes from limestone aquifers, where calcium carbonate, a harmless compound that can make water taste ‘crisper’, is found.
Other factors that affect the formation of this film include milk, sugar or lemon added to the tea, the brewing temperature, and the concentration of the tea.
The team studied how the strength of the film changed with water hardness by placing a metal device on the surface of the tea and rotating it. “The rotation of that device is carefully controlled, and the resistance to rotation that the film applies is what allows us to determine its strength.
They found that the more calcium carbonate in the water, the stronger the film woul.... “If you were to make a cup of tea in perfectly pure water, it would not form a film at all, but the tea would taste quite bitter
The team’s findings could be useful in industrial settings, where creating conditions to form a strong film could improve the shelf life in packaged tea drinks.
https://aip.scitation.org/doi/10.1063/5.0059760
https://www.sciencefocus.com/science/put-down-the-filter-tea-made-w...
Sep 9, 2021
Dr. Krishna Kumari Challa
Exposure to traffic noise linked to higher dementia risk
Exposure to noise from traffic on roads and railways over a long period is associated with a higher risk of developing dementia, especially Alzheimer's disease, suggests a study published in The BMJ recently.
The researchers estimate that as many as 1,216 out of the 8,475 cases of dementia registered in Denmark in 2017 could be attributed to these noise exposures, indicating a great potential for dementia prevention through reduction in traffic related noise.
Worldwide, the number of people with dementia is expected to exceed 130 million by 2050, making it a costly and growing global health crisis. Besides well established risk factors, such as cardiovascular diseases and unhealthy lifestyle, environmental exposures may also play a role in the development of dementia.
Transportation noise is considered the second worst environmental risk factor for public health in Europe after air pollution, and around a fifth of the European population is exposed to transportation noise above the recommended level of 55 dB (decibels).
Studies have consistently linked transportation noise to various diseases and health conditions, such as coronary heart disease, obesity, and diabetes. There is, however, little research on transportation noise and dementia and findings are inconsistent.
To address this, researchers investigated the association between long term residential exposure to road traffic and railway noise and risk of dementia among two million adults aged over 60 and living in Denmark between 2004 and 2017.
The researchers estimated road traffic and railway noise at the most and least exposed sides (or façades) of all residential addresses in Denmark.
They then analyzed national health registers to identify cases of all-cause dementia and different types of dementia (Alzheimer's disease, vascular dementia, and Parkinson's disease related dementia) over an average of 8.5 years.
They found 103,500 new cases of dementia during the study period.
After taking account of potentially influential factors related to residents and their neighborhoods, the researchers found that a 10-year average exposure to road traffic and railway noise at the most and least exposed sides of buildings was associated with a higher risk of all-cause dementia.
These associations showed a general pattern of higher risk with higher noise exposure, but with a leveling off or even small declines in risk at higher noise levels.
Further analysis by type of dementia showed both road traffic and railway noise were associated with a higher risk of Alzheimer's disease—up to 27% higher for exposure to road traffic noise of 55 dB and up to 24% higher for exposure to railway noise of 50 dB compared with less than 40 dB.
However, only road traffic noise was associated with an increased risk of vascular dementia, and not railway noise.
Residential exposure to transportation noise in Denmark and incidence of dementia: national cohort study, BMJ (2021). www.bmj.com/content/374/bmj.n1954
Editorial: Noise exposure and dementia: a rising concern in ageing populations, www.bmj.com/content/374/bmj.n2120
https://medicalxpress.com/news/2021-09-exposure-traffic-noise-linke...
Sep 10, 2021
Dr. Krishna Kumari Challa
Scientists solve mystery of icy plumes that may foretell deadly supercell storms
The most devastating tornadoes are often preceded by a cloudy plume of ice and water vapor billowing above a severe thunderstorm. New research reveals the mechanism for these plumes could be tied to 'hydraulic jumps' -- a phenomenon Leonardo Da Vinci observed more than 500 years ago.
When a cloudy plume of ice and water vapor billows up above the top of a severe thunderstorm, there's a good chance a violent tornado, high winds or hailstones bigger than golf balls will soon pelt the Earth below.
A new Stanford University-led study, published Sept. 10 in Science, reveals the physical mechanism for these plumes, which form above most of the world's most damaging tornadoes.
Previous research has shown they're easy to spot in satellite imagery, often 30 minutes or more before severe weather reaches the ground. "The question is, why is this plume associated with the worst conditions, and how does it exist in the first place? That's the gap that we are starting to fill," said atmospheric scientist Morgan O'Neill, lead author of the new study.
The research comes just over a week after supercell thunderstorms and tornadoes spun up among the remnants of Hurricane Ida as they barreled into the U.S. Northeast, compounding devastation wrought across the region by record-breaking rainfall and flash floods.
Understanding how and why plumes take shape above powerful thunderstorms could help forecasters recognize similar impending dangers and issue more accurate warnings without relying on Doppler radar systems, which can be knocked out by wind and hail -- and have blind spots even on good days. In many parts of the world, Doppler radar coverage is nonexistent.
"If there's going to be a terrible hurricane, we can see it from space. We can't see tornadoes because they're hidden below thunderstorm tops. We need to understand the tops better," said O'Neill, who is an assistant professor of Earth system science at Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth).
part 1
Sep 10, 2021
Dr. Krishna Kumari Challa
Supercell storms and exploding turbulence
The thunderstorms that spawn most tornadoes are known as supercells, a rare breed of storm with a rotating updraft that can hurtle skyward at speeds faster than 150 miles an hour, with enough power to punch through the usual lid on Earth's troposphere, the lowest layer of our atmosphere.
In weaker thunderstorms, rising currents of moist air tend to flatten and spread out upon reaching this lid, called the tropopause, forming an anvil-shaped cloud. A supercell thunderstorm's intense updraft presses the tropopause upward into the next layer of the atmosphere, creating what scientists call an overshooting top. "It's like a fountain pushing up against the next layer of our atmosphere," O'Neill said.
As winds in the upper atmosphere race over and around the protruding storm top, they sometimes kick up streams of water vapor and ice, which shoot into the stratosphere to form the tell-tale plume, technically called an Above-Anvil Cirrus Plume, or AACP.
The rising air of the overshooting top soon speeds back toward the troposphere, like a ball that accelerates downward after cresting aloft. At the same time, air is flowing over the dome in the stratosphere and then racing down the sheltered side.
Using computer simulations of idealized supercell thunderstorms, O'Neill and colleagues discovered that this excites a downslope windstorm at the tropopause, where wind speeds exceed 240 miles per hour. "Dry air descending from the stratosphere and moist air rising from the troposphere join in this very narrow, crazy-fast jet. The jet becomes unstable and the whole thing mixes and explodes in turbulence," O'Neill said. "These speeds at the storm top have never been observed or hypothesized before."
part2
Sep 10, 2021
Dr. Krishna Kumari Challa
Hydraulic jump
Scientists have long recognized that overshooting storm tops of moist air rising into the upper atmosphere can act like solid obstacles that block or redirect airflow. And it's been proposed that waves of moist air flowing over these tops can break and loft water into the stratosphere. But no research to date has explained how all the pieces fit together.
The new modeling suggests the explosion of turbulence in the atmosphere that accompanies plumed storms unfolds through a phenomenon called a hydraulic jump. The same mechanism is at play when rushing winds tumble over mountains and generate turbulence on the downslope side, or when water speeding smoothly down a dam's spillway abruptly bursts into froth upon joining slower-moving water below.
Leonardo DaVinci observed the phenomenon in flowing water as early as the 1500s, and ancient Romans may have sought to limit hydraulic jumps in aqueduct designs. But until now atmospheric scientists have only seen the dynamic induced by solid topography. The new modeling suggests a hydraulic jump can also be triggered by fluid obstacles in the atmosphere made almost entirely of air and which are changing shape every second, miles above the Earth's surface.
The simulations suggest the onset of the jump coincides with a surprisingly rapid injection of water vapor into the stratosphere, upwards of 7000 kilograms per second. That's two to four times higher than previous estimates. Once it reaches the overworld, water may stay there for days or weeks, potentially influencing the amount and quality of sunlight that reaches Earth via destruction of ozone in the stratosphere and warming the planet's surface. "In our simulations that exhibit plumes, water reaches deep into the stratosphere, where it possibly could have more of a long-term climate impact," said co-author Leigh Orf, an atmospheric scientist at the University of Wisconsin-Madison.
According to O'Neill, high-altitude NASA research aircraft have only recently gained the ability to observe the three-dimensional winds at the tops of thunderstorms, and have not yet observed AACP production at close range. "We have the technology now to go verify our modeling results to see if they're realistic," O'Neill said. "That's really a sweet spot in science."
This research was supported by the National Science Foundation and the NASA Precipitation Measurement Mission and Ground Validation program.
Story Source:
Materials provided by Stanford University. Original written by Josie Garthwaite. Note: Content may be edited for style and length.
Journal Reference:
https://www.sciencedaily.com/releases/2021/09/210909141231.htm
Sep 10, 2021
Dr. Krishna Kumari Challa
We Asked a NASA Scientist – Do Aliens Exist?
Sep 10, 2021
Dr. Krishna Kumari Challa
COVID advances win Breakthrough prizes
Techniques that have helped scientists to understand COVID-19 have scooped two out of five of the most lucrative awards in science and.... “These two awards are for research that has had such an impact on the world that they elevate the stature of the Breakthrough Prize,” says chemical biologist Yamuna Krishnan. “They have been saving lives by the millions.” This year’s US$3-million Breakthrough prizes went to:
https://www.nature.com/articles/d41586-021-02449-y?utm_source=Natur...
Sep 10, 2021