Why men and women feel touch differently

Why women generally seem to have a more acute sense of touch than men?

 Women are better than men at touch discrimination—although not because they have smaller fingers, but because in general they have softer fingers. 

But demonstrating the "why" behind the gender difference, first published in November 2023 in the Journal of Physiology, continues to be a cited topic of interest. The insight could be useful as engineers develop softer sensor materials for wearable technology, improve prosthetics with a sense of touch, or design better interfaces for surgical robots.

The experimental design combined novel 3D imaging and biomechanical observations of skin and how it deforms when pressed, statistical analysis and machine learning, and experiments to test how the participants used touch to perceive objects.
They found that softer skin resulted in greater rates of change in surface contact with objects, which correlated with a greater ability to distinguish small changes in the objects' stiffness.

"The mechanism seems to be that attributes of surface contact control the recruitment of sensory nerve fibers in the skin".

For those who'd like to improve their touch perception, the researchers said, apply hyaluronic acid, an effective skin moisturizer and softener.

Bingxu Li et al, An individual's skin stiffness predicts their tactile discrimination of compliance, The Journal of Physiology (2023). DOI: 10.1113/JP285271

Engineered microbes found to repel mosquitoes

Genetically-engineered human skin bacteria can make mice less attractive to mosquitoes for 11 days. Mosquitoes transmit a host of deadly diseases, including malaria, West Nile, dengue, yellow fever, and Zika. Female mosquitoes on the hunt for a blood meal tune into scents released by skin microbes that live on their targets.

Researchers engineered versions of the common human  skin commensals Staphylococcus epidermidis and Corynebacterium amycolatum to produce much less of a form of lactic acid known to attract mosquitoes. The work is published in the journal PNAS Nexus.

The authors tested the microbes alone and found the engineered version of S. epidermidis attracted about half as many Aedes aegypti and Anopheles gambiae mosquitoes and about 22% fewer Culex quinquefasciatus as the wildtype versions of the microbes.

The authors also tried the engineered microbes on mice. Painting the mice with wildtype S. epidermidis attracted mosquitos. However, painting the mice with engineered S. epidermidis reduced mosquito attraction by up to 64.4%, compared with wildtype, starting three days after the microbe was applied.

The effect lasted for 11 days. Trials with engineered C. amycolatum had similar results. In addition, a smaller proportion of mosquitoes that landed on mice painted with engineered microbes bit the mice. According to the authors, the results suggest the feasibility of creating a living and long-lasting engineered microbiome-based mosquito repellent.

 Feng Liu et al, Engineered skin microbiome reduces mosquito attraction to mice, PNAS Nexus (2024). DOI: 10.1093/pnasnexus/pgae267

Study uncovers unique brain plasticity in people born blind

A study by neuroscientists reveals that the part of the brain that receives and processes visual information in sighted people develops a unique connectivity pattern in people born blind. They say this pattern in the primary visual cortex is unique to each person—akin to a fingerprint.

The findings, described July 30, 2024, in PNAS, have profound implications for understanding brain development and could help launch personalized rehabilitation and sight restoration strategies.

For decades, scientists have known that the visual cortex in people born blind responds to a myriad of stimuli, including touch, smell, sound localization, memory recall and response to language. However, the lack of a common thread linking the tasks that activate primary areas in the visual cortex has perplexed researchers.

The new study offers a compelling explanation: differences in how each individual's brain organizes itself.

We don't see this level of variation in the visual cortex connectivity among individuals who can see—the connectivity of the visual cortex is usually fairly consistent, say the researchers.

The connectivity pattern in people born blind is more different across people, like an individual fingerprint, and is stable over time—so much so that the individual person can be identified from the connectivity pattern.

Lénia Amaral et al, Longitudinal stability of individual brain plasticity patterns in blindness, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2320251121

Study links TB strain infectivity to shared geographic background

For some forms of tuberculosis, the chances that an exposed person will become infected depend on whether the individual and the bacteria share a hometown, according to a new study comparing how different strains move through mixed populations in cosmopolitan cities.

Results of the research, led by Harvard Medical School scientists and published in Nature Microbiology, provide the first hard evidence of long-standing observations that have led scientists to suspect that pathogen, place, and human host collide in a distinctive interplay that influences infection risk and fuels differences in susceptibility to infection.

The study strengthens the case for a long-standing hypothesis in the field that specific bacteria and their human hosts likely co-evolved over hundreds or thousands of years, the researchers said.

The findings may also help inform new prevention and treatment approaches for tuberculosis, a wily pathogen that sickens more than 10 million people and causes more than a million deaths worldwide each year, according to the World Health Organization.

In the current analysis, believed to be the first controlled comparison of TB strains' infectivity in populations of mixed geographic origins, the researchers custom built a study cohort by combining case files from patients with TB in New York City, Amsterdam, and Hamburg. Doing so gave them enough data to power their models.

The analysis showed that close household contacts of people diagnosed with a strain of TB from a geographically restricted lineage had a 14% lower rate of infection and a 45% lower rate of developing active TB disease compared with those exposed to a strain belonging to a widespread lineage.

The study also showed that strains with narrow geographic ranges are much more likely to infect people with roots in the bacteria's native geographic region than people from outside the region.

The researchers found that the odds of infection dropped by 38% when a contact is exposed to a restricted pathogen from a geographic region that doesn't match the person's background, compared with when a person is exposed to a geographically restricted microbe from a region that does match their home country. This was true for people who had lived in the region themselves and for people whose two parents could each trace their heritage to the region.

This pathogen-host affinity points to a shared evolution between humans and microbes with certain biological features rendering both more compatible and fueling the risk for infection, the researchers said.

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the new study showed that for geographically restricted strains, whether a person has ancestors who lived where the strain is common was an even bigger predictor of infection risk than bacterial load in the sputum. In the cases analyzed in the study, this risk of common ancestry even outweighed the risk stemming from having diabetes and other chronic diseases previously shown to render people more susceptible to infection.

The findings add to a growing body of evidence of the importance of paying attention to the wide variation between different lineages of tuberculosis and to the details of how different lineages of tuberculosis interact with different host populations.

Previous studies have shown that some genetic groups of TB are more prone to developing drug resistance and that TB vaccines appear to work better in some places than others. There is also evidence that some treatment regimens might be better suited to some strains of TB than others.

"These findings emphasize how important it is to understand what makes different strains of TB behave so differently from one another, and why some strains have such a close affinity for specific, related groups of people.

In addition to the analysis of clinical, genomic, and public health data, the researchers also tested the ability of different strains of TB to infect human macrophages, a type of immune cell that TB hijacks to cause infection and disease. The researchers grew cells from donors from different regions. Once again, cell lines from people with ancestry that matched the native habitat of a restricted strain of tuberculosis bacteria were more susceptible to the germs than cells from people from outside the area, mirroring the results of their epidemiologic study.

Differential rates of Mycobacterium tuberculosis transmission associate with host–pathogen sympatry, Nature Microbiology (2024). DOI: 10.1038/s41564-024-01758-y

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Warming breaks down symbiosis

Hotter conditions prevent two tiny organisms working together for mutual benefit, new research shows.

Scientists studied a single-celled organism (Paramecium bursaria) which can absorb and host algae (Chlorella spp). This pairing is common in freshwater worldwide, and their symbiotic relationship provides benefits including trading of nutrients and protection for the algae.

But when scientists made the water 5°C warmer, the partnership stopped working—and the results suggest the algae may even become parasitic.

The breakdown of such relationships could have a major impact on ecosystems.

The paper, published in the journal Aquatic Biology, is titled "One year of warming leads to the total loss of productivity in a widespread photosymbiosis."

This kind of relationship—called photosymbiosis—is an important part of freshwater and ocean ecosystems.

To illustrate their importance, these relationships provide around half of all marine photosynthesis.

A well-known example is found in coral reefs—where the reef-building corals host resident photosynthetic partners. In recent years, we have seen many high-profile 'bleaching' events—when corals expel these partners, often due to high temperatures, leaving them at risk of stress and mortality.

B Makin et al, One year of warming leads to the total loss of productivity in a widespread photosymbiosis, Aquatic Biology (2024). DOI: 10.3354/ab00769

Study finds regular aspirin use associated with greatest reduction in colorectal cancer among those most at risk

Regular aspirin may help lower risk of colorectal cancer in people with greater lifestyle-related risk factors for the disease, according to a study by researchers. 

 The study, published in JAMA Oncology, could encourage a more nuanced approach to preventive aspirin use.

The U.S. Preventive Services Task Force previously recommended daily low-dose aspirin to prevent cardiovascular events and colorectal cancer in all adults ages 50 to 59 (the highest risk age group for colorectal cancer). In 2016, they withdrew the recommendation in part due to concerns about aspirin increasing the risk of gastrointestinal bleeding.

For the study, researchers analyzed the health data from 107,655 participants from the Nurses' Health Study and Health Professionals Follow-Up Study. They compared the colorectal cancer rates in those who took aspirin regularly with those who did not take aspirin regularly. Regular aspirin use was defined as either two or more standard dose (325 mg) tablets per week or daily low-dose (81 mg) aspirin.

Study participants were followed starting from an average age of 49.4 years. Those who regularly took aspirin had a colorectal cancer 10-year cumulative incidence of 1.98%, compared to 2.95% among those who did not take aspirin.

The benefit of aspirin was largest among those with the unhealthiest lifestyles. Those with the lowest healthy lifestyle scores (unhealthiest) had a 3.4% chance of getting colorectal cancer if they did not take regular aspirin and a 2.12% chance of getting colorectal cancer if they took aspirin regularly.

By contrast, in those with the highest healthy lifestyle scores (healthiest), the colorectal cancer rates were 1.5% in regular aspirin-taking group and 1.6% in the non-regular aspirin group. This means that in the least healthy group, treating 78 patients with aspirin would prevent one case of colorectal cancer over a 10-year period, while it would take treating 909 patients to prevent one case for the healthiest group.

Lifestyle scores were calculated based on  body mass index, frequency of cigarette and alcohol use, physical activity, and adherence to a high-quality diet.

These results show that aspirin can proportionally lower the markedly elevated risk in those with multiple risk factors for colorectal cancer.

In contrast, those with a healthier lifestyle have a lower baseline risk of colorectal cancer, and, therefore, their benefit from aspirin was still evident, albeit less pronounced.

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One outcome of the study could be that "health care providers might more strongly consider recommending aspirin to patients who have less healthy lifestyles.
Previous studies have found evidence to suggest aspirin can reduce the production of pro-inflammatory proteins, known as prostaglandins, that can promote the development of cancer. Aspirin may also block signaling pathways that cause cells to grow out of control, influence the immune response against cancer cells, and block the development of blood vessels that supply nutrients to cancer cells.

Aspirin likely prevents colorectal cancer through multiple mechanisms.
The study did not assess potential side effects of daily aspirin use, such as bleeding. In addition, while the study tried to control for a wide range of risk factors for colorectal cancer, in comparing non-aspirin and aspirin-taking groups with the same level of risk factors, because this was an observational study, it is possible there may have been additional factors that influenced the findings.

 Aspirin Use and Incidence of Colorectal Cancer According to Lifestyle Risk, JAMA Oncology (2024). DOI: 10.1001/jamaoncol.2024.2503

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Paper cut physics: the physics behind why some paper is more prone to cut fingers

We all know what it’s like to pick up a sheet of paper, only to get a painful paper cut. The injury is usually small and shallow, but it can really hurt!
Your body has hundreds of nerves. These nerves are spread throughout your body, from head to toe.
In your hands and fingers, though, the nerve endings are densely packed together. So, they’re more sensitive than other areas, like your back or arm.
This explains why paper cuts hurt so much. They commonly affect the hands and fingers, which have a higher density of nerve endings.
But what about all the blood? Well, the capillaries in your hands and fingers are closely packed together. This means paper cuts can cause a lot of bleeding because of how concentrated blood can be in your hands.

In experiments with a gelatin replica of human tissue, researchers found that a thin sheet of paper tended to buckle before it could cut. Thick paper typically indented the material but didn’t pierce it: Like a dull knife blade, it didn’t concentrate force into a small enough area. A thickness of around 65 micrometers was a paper cut sweet spot — or sore spot — physicist Kaare Jensen and colleagues report in a paper to appear in Physical Review E.

That makes dot matrix printer paper the most treacherous, the researchers say. (That paper is seldom used today ). Paper from various magazines was a close second in the scientists’ tests. 

The angle of slicing also played a role. Paper pressed straight down into the gelatin was less likely to cut than paper that cleaved across and down.

S.F. Arnbjerg-Nielsen, M.D. Biviano and K.H. Jensen. Competition between slicing and buckling underlies the erratic natu.... Physical Review E, in press, 2024.

Almost Half of Dementia Cases Avoidable by Addressing 14 Risk Factors, Major Study Finds

Millions of cases of dementia could be prevented or delayed by reducing a range of risk factors according to a major new study, though outside experts warn that such measures can only go so far.

The debilitating condition, which progressively robs people of their memories, cognitive abilities, language and independence, currently affects more than 55 million people across the world. Dementia is caused by a range of diseases, the most common of which is Alzheimer's.

A huge review of the available evidence published in The Lancet journal on Wednesday said that the "potential for prevention is high" in the fight against dementia.

At the time, the international team of researchers estimated that 40 percent of dementia cases were linked to 12 risk factors.

The factors included people having a lower level of education, hearing problems, high blood pressure, smoking, obesity,  depression physical inactivity,  diabetes, excessive drinking, traumatic brain injury, air pollution and social isolation.

The latest update adds two more risk factors: vision loss and high cholesterol.

Added Sugar in Your Diet May Speed Up Your Body's Biological Aging

Eating large amounts of food with added sugar could have a hyperactive effect on the body's ticking biological clock, even when the rest of a person's diet remains otherwise healthy.

A new study among 342 Black and White middle-aged women (please note that the sample size is very low) has found those who eat high quantities of added sugar have 'older-looking' cells.

The findings could help explain why some people seem to age faster or slower than others who have lived the same number of years. Sugar intake could be an important, overlooked factor.

Along with the occasional mutation, our DNA can accumulate less permanent edits over time. These so-called epigenetic changes often act like chemical padlocks, deactivating genes and altering how the body's genetic code is expressed for a time.
A collection of transient edits is referred to as an epigenetic clock, and can be a useful way to guess at a person's true biological age. Epigenetic changes can be read by scientists to better understand how old a cell is and what damages or stresses it has experienced.

Diet, lifestyle, genetics, and disease are all known to affect how quickly a person's epigenetic clock ticks, but this is one of the first studies to examine how sugar specifically plays a role. It also includes a diverse cohort.

The findings suggest that added sugar can alter epigenetic switches related to aging more quickly than healthier foods can turn them off, regardless of whether healthy nutrients are also present.

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Female participants who ate a diet rich in vitamins, minerals, and antioxidants, for instance, had cells with the 'youngest'-looking epigenetic age. Those on the Mediterranean diet were observed to have the slowest epigenetic clocks.

Still, the more added sugar a person consumed each day, the older their salivary DNA appeared to scientists, even when their meals were rich in foods that maintain and repair DNA.

This was true even when accounting for education, lifestyle factors, and the current health of participants.

On average, women in the study ate just over 60 grams of sugar a day, although some ate more than 300 grams a day.
The findings suggest that added sugar can significantly accelerate cellular aging, but it is important to note that this study is only based on food records collected over three non-consecutive days, and one salivary swab.

Previous studies have suggested that cells can appear epigenetically 'younger' or 'older' depending on when in the day their DNA was sampled, so longer term studies among both sexes are needed before further conclusions can be drawn.

https://jamanetwork.com/journals/jamanetworkopen/article-abstract/2...

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A bio-inspired vision sensor that can detect spectrally distinctive features

The ability to detect objects in settings with unfavorable lighting, for example at night, in shadowed locations or in foggy conditions, could greatly improve the reliability of autonomous vehicles and mobile robotic systems. Most widely employed computer vision methods, however, have been found to perform under poor lighting.

Researchers  recently introduced a new bio-inspired vision sensor that can adapt to the spectral features of the environments it captures, thus successfully detecting objects in a wider range of lighting conditions. This newly developed sensor, introduced in a paper published in Nature Electronics, is based on an array of photodiodes arranged back-to-back.

The primary objective of this recent work was to design a vision sensor that is better than other sensors at recognizing objects in an environment marked by strong light interference and when there is smoke or fog in the air. The sensor they planned to develop would also collect data with minimal time latency, consuming very little power.

Bangsen Ouyang et al, Bioinspired in-sensor spectral adaptation for perceiving spectrally distinctive features, Nature Electronics (2024). DOI: 10.1038/s41928-024-01208-x.

Brain activity associated with specific words is mirrored between speaker and listener during a conversation

When two people interact, their brain activity becomes synchronized, but it was unclear until now to what extent this "brain-to-brain coupling" is due to linguistic information or other factors, such as body language or tone of voice.

Researchers report August 2 in the journal Neuron that brain-to-brain coupling during conversation can be modeled by considering the words used during that conversation, and the context in which they are used.

Researchers could see linguistic content emerge word-by-word in the speaker's brain before they actually articulate what they're trying to say, and the same linguistic content rapidly reemerges in the listener's brain after they hear it.

To communicate verbally, we must agree on the definitions of different words, but these definitions can change depending on the context. For example, without context, it would be impossible to know whether the word "cold" refers to temperature, a personality trait, or a respiratory infection.

The contextual meaning of words as they occur in a particular sentence, or in a particular conversation, is really important for the way that we understand each other.

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To examine the role of context in driving brain coupling, the team collected brain activity data and conversation transcripts from pairs of epilepsy patients during natural conversations.

The patients were undergoing intracranial monitoring using electrocorticography for unrelated clinical purposes at the New York University School of Medicine Comprehensive Epilepsy Center. Compared to less invasive methods like fMRI, electrocorticography records extremely high-resolution brain activity because electrodes are placed in direct contact with the surface of the brain.

Next, the researchers used the large language model GPT-2 to extract the context surrounding each of the words used in the conversations, and then used this information to train a model to predict how brain activity changes as information flows from speaker to listener during conversation.

Using the model, the researchers were able to observe brain activity associated with the context-specific meaning of words in the brains of both speaker and listener.

They showed that word-specific brain activity peaked in the speaker's brain around 250 ms before they spoke each word, and corresponding spikes in brain activity associated with the same words appeared in the listener's brain approximately 250 ms after they heard them.

Compared to previous work on speaker–listener brain coupling, the team's context-based approach model was better able to predict shared patterns in brain activity. This shows just how important context is, because it best explains the brain data. Large language models take all these different elements of linguistics like syntax and semantics and represent them in a single high-dimensional vector. This work shows that this type of unified model is able to outperform other hand-engineered models from linguistics.

A shared model-based linguistic space for transmitting our thoughts from brain to brain in natural conversations, Neuron (2024). DOI: 10.1016/j.neuron.2024.06.025. www.cell.com/neuron/fulltext/S0896-6273(24)00460-4

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Scientists pin down the origins of the moon's tenuous atmosphere

While the moon lacks any breathable air, it does host a barely-there atmosphere. Since the 1980s, astronomers have observed a very thin layer of atoms bouncing over the moon's surface. This delicate atmosphere—technically known as an "exosphere"—is likely a product of some kind of space weathering. But exactly what those processes might be has been difficult to understand with any certainty.

Now, scientists  say they have identified the main process that formed the moon's atmosphere and continues to sustain it today. In a study appearing in Science Advances, the team reports that the lunar atmosphere is primarily a product of "impact vaporization."

In their study, the researchers analyzed samples of lunar soil collected by astronauts during NASA's Apollo missions.

Their analysis suggests that over the moon's 4.5-billion-year history its surface has been continuously bombarded, first by massive meteorites, then more recently, by smaller, dust-sized "micrometeoroids."

These constant impacts have kicked up the lunar soil, vaporizing certain atoms on contact and lofting the particles into the air. Some atoms are ejected into space, while others remain suspended over the moon, forming a tenuous atmosphere that is constantly replenished as meteorites continue to pelt the surface.

The researchers found that impact vaporization is the main process by which the moon has generated and sustained its extremely thin atmosphere over billions of years.

Nicole Nie, Lunar Soil Record of Atmosphere Loss over Eons, Science Advances (2024). DOI: 10.1126/sciadv.adm7074. www.science.org/doi/10.1126/sciadv.adm7074

Researchers demonstrate mechanism that may have stabilized the first RNA molecules

The origins of life remain a major mystery. How were complex molecules able to form and remain intact for prolonged periods without disintegrating? A team at ORIGINS, a Munich-based Cluster of Excellence, has demonstrated a mechanism that could have enabled the first RNA molecules to stabilize in the primordial soup.

When two RNA strands combine, their stability and lifespan increase significantly. The work is published in the journal Nature Chemistry.

In all likelihood, life on Earth began in water, perhaps in a tide pool that was cut off from seawater at low tide but flooded by waves at high tide. Over billions of years, complex molecules like DNA, RNA and proteins formed in this setting before, ultimately, the first cells emerged. 

RNA is a fascinating molecule. It can store information and also catalyze biochemical reactions. Scientists therefore think that RNA must have been the first of all complex molecules to form.

The problem, however, is that active RNA molecules are composed of hundreds or even thousands of bases and are very unstable. When immersed in water, RNA strands quickly break down into their constituent parts—a process known as hydrolysis. So, how could RNA have survived in the primordial soup?

In laboratory testing, the researchers from TUM and LMU used a model system of RNA bases that join together more easily than naturally occurring bases in our cells today.

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The researchers added these fast-joining RNA bases into a watery solution, provided an energy source and examined the length of the RNA molecules that formed. Their findings were sobering, as the resulting strands of up to five base pairs only survived for a matter of minutes.

The results were different, however, when the researchers started by adding short strands of pre-formed RNA. The free complementary bases quickly joined with this RNA in a process called hybridization. Double strands of three to five base pairs in length formed and remained stable for several hours.

The exciting part is that double strands lead to RNA folding, which can make the RNA catalytically active.

Double-stranded RNA therefore has two advantages: it has an extended lifespan in the primordial soup and serves as the basis for catalytically active RNA.

Another characteristic of double-stranded RNA could have helped bring about the origin of life. It is firstly important to note that RNA molecules can also form protocells. These are tiny droplets with an interior fully separated from the outside world. Yet, these protocells do not have a stable cell membrane and so easily merge with other protocells, which causes their contents to mix.

This is not conducive to evolution because it prevents individual protocells from developing a unique identity. However, if the borders of these protocells are composed of double-stranded DNA, the cells become more stable and merging is inhibited.

Christine M. E. Kriebisch et al, Template-based copying in chemically fuelled dynamic combinatorial libraries, Nature Chemistry (2024). DOI: 10.1038/s41557-024-01570-5

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Coinfecting viruses obstruct each other's cell invasion

The process by which phages—viruses that infect and replicate within bacteria—enter cells has been studied for over 50 years. In a new study, researchers  have used cutting-edge techniques to look at this process at the level of a single cell.

The field of phage biology has seen an explosion over the last decade because more researchers are realizing the significance of phages in ecology, evolution, and biotechnology. 

This new work is unique because we looked at phage infection at the level of individual bacterial cells.

The process of phage infection involves the attachment of the virus to the surface of a bacterium. Following this, the virus injects its genetic material into the cell. After entering, a phage can either force the cell to produce more phages and eventually explode, a process called cell lysis, or the phage can integrate its genome into the bacterial one and remain dormant, a process called lysogeny. The outcome depends on how many phages are simultaneously infecting the cell. A single phage causes lysis, while infection by multiple phages results in lysogeny.

In the current study, the researchers wanted to ask whether the number of infecting phages that bind to the bacterial surface corresponds to the amount of viral genetic material that is injected into the cell. To do so, they fluorescently labeled both the protein shell of the phages and the genetic material inside. They then grew Escherichia coli, used different concentrations of infecting phages, and tracked how many of them were able to inject their genetic material into E. coli.

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Scientists have known since the 70s that when multiple phages infect the same cell, it impacts the outcome of the infection. In this paper, they were able to take precise measurements.
The researchers were surprised to find that the entry of a phage's genetic material could be impeded by the other coinfecting phages. They found that when there were more phages attached to the surface of the cell, relatively fewer of them were able to enter.
Their data shows that the first stage of infection, phage entry, is an important step that was previously underappreciated. The researchers found that the coinfecting phages were impeding each other's entry by perturbing the electrophysiology of the cell.
The outermost layer of bacteria is constantly dealing with the movement of electrons and ions that are crucial for energy generation and transmitting signals in and out of the cell. Over the past decade, researchers have started realizing the importance of this electrophysiology in other bacterial phenomena, including antibiotic resistance. This paper opens a new avenue for research in bacterial electrophysiology—its role in phage biology.
By influencing how many phages actually enter, these perturbations affect the choice between lysis and lysogeny. This study also shows that entry can be impacted by environmental conditions such as the concentration of various ions.

 Thu Vu Phuc Nguyen et al, Coinfecting phages impede each other's entry into the cell, Current Biology (2024). DOI: 10.1016/j.cub.2024.05.032

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Researchers use vibrations from traffic to measure underground soil moisture

Researchers have developed a new method to measure soil moisture in the shallow subterranean region between the surface and underground aquifers. This region, called the vadose zone, is crucial for plants and crops to obtain water through their roots.

However, measuring how this underground moisture fluctuates over time and between geographical regions has traditionally relied on satellite imaging, which only gives low-resolution averages and cannot penetrate below the surface. Additionally, moisture within the vadose zone changes rapidly—a thunderstorm can saturate a region that dries out a few days later.

The new method relies upon seismic technology that normally measures how the ground shakes during earthquakes. However, it can also detect the vibrations of human activity, like traffic. As these vibrations pass through the ground, they are slowed down by the presence of water—the more moisture, the slower the vibration moves. The new study measures the water content in the vadose zone through seismic rumblings from everyday traffic.

The new method is based on a technique pioneered in the  lab, called distributed acoustic sensing (DAS). With this technique, lasers are pointed into unused underground fiber-optic cables (like the kind that provides the internet).

As a seismic wave, or any kind of vibration, passes through the cable, the laser light bends and refracts. Measuring the wiggles in this laser light gives researchers information about the passing wave, making the 10-kilometer cable equivalent to a line of thousands of conventional seismic sensors.

The ability to measure vadose zone moisture in real time is crucial for managing water use and conservation efforts. 

Fiber-optic seismic sensing of vadose zone soil moisture dynamics, Nature Communications (2024).

Streetlights running all night makes leaves so tough that insects can't eat them, threatening the food chain

Light pollution disrupts circadian rhythms and ecosystems worldwide—but for plants, dependent on light for photosynthesis, its effects could be profound. Now scientists writing in Frontiers in Plant Science have found that exposure to high levels of artificial light at night makes tree leaves grow tougher and harder for insects to eat, threatening urban food chains.

Compared to natural ecosystems, tree leaves in most urban ecosystems generally show little sign of insect damage. Scientists were curious as to why. Their observations show that   in two of the most common tree species in Beijing, artificial light at night led to increased leaf toughness and decreased levels of leaf herbivory.

Artificial light has increased levels of night-time brightness by almost 10%: most of the world's population experiences light pollution every night. Because plant properties affect their interactions with other plants and animals, any changes to plants caused by artificial light could have a significant impact on the ecosystem.

Leaves that are free of insect damage may bring comfort to people, but not insects. Herbivory is a natural ecological process that maintains the biodiversity of insects.

The scientists suspected that plants experiencing high levels of artificial light would focus on defense rather than growth, producing tougher leaves with more chemical defense compounds. 

In their experiments,  they  found that the more intense the light, the more frequently they encountered leaves that showed no signs at all of herbivory.

It is possible that trees exposed to artificial light at night may extend their photosynthesis duration. Additionally, these leaves might allocate a greater proportion of resources to structural compounds, such as fibers, which could lead to an increase in leaf toughness.

Lower levels of herbivory imply lower abundances of herbivorous insects, which could in turn result in lower abundances of predatory insects, insect-eating birds, and so on. 

If there 're less pollinating insects, that would also affect the fruit yield.

 Artificial light at night decreases leaf herbivory in typical urban areas, Frontiers in Plant Science (2024). DOI: 10.3389/fpls.2024.1392262

New biomaterial regrows damaged cartilage in joints

scientists have developed a new bioactive material that successfully regenerated high-quality cartilage in the knee joints of a large-animal model.

Although it looks like a rubbery goo, the material is actually a complex network of molecular components, which work together to mimic cartilage's natural environment in the body.

In the new study, the researchers applied the material to damaged cartilage in the animals' knee joints. Within just six months, the researchers observed evidence of enhanced repair, including the growth of new cartilage containing the natural biopolymers (collagen II and proteoglycans), which enable pain-free mechanical resilience in joints.

Stupp, Samuel I., A bioactive supramolecular and covalent polymer scaffold for cartilage repair in a sheep model, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2405454121

Sometimes mental effort is associated with unpleasant feelings, study says

If somebody complains that it hurts to think, they may be onto something, as mental exertion appears to be associated with unpleasant feelings in many situations, according to research published in the journal Psychological Bulletin.

Managers often encourage employees, and teachers often encourage students to exert mental effort. On the surface, this seems to work well: Employees and students do often opt for mentally challenging activities. From this, you may be tempted to conclude that employees and students tend to enjoy thinking hard. But the study results suggest that this conclusion would be false: In general, people really dislike mental effort.

Researchers conducted a meta-analysis of 170 studies, published between 2019 and 2020 and comprising 4,670 participants, to examine how people generally experience mental effort. They did so by testing whether mental effort is associated with unpleasant feelings and whether that association depends on the task or the population involved.

The studies used a variety of participants (e.g., health care employees, military employees, amateur athletes, college students) from 29 countries and involved 358 different cognitive tasks (e.g., learning a new technology, finding one's way around an unfamiliar environment, practicing golf swings, playing a virtual reality game).

In all studies analyzed, participants reported the level of effort they exerted as well as the extent to which they experienced unpleasant feelings such as frustration, irritation, stress or annoyance.

Across all populations and tasks, the greater the mental effort, the greater the unpleasantness experienced by participants.

These findings show that mental effort feels unpleasant across a wide range of populations and tasks.

This is important for professionals, such as engineers and educators, to keep in mind when designing tasks, tools, interfaces, apps, materials or instructions. When people are required to exert substantial mental effort, you need to make sure to support or reward them for their effort, say the researchers.

One interesting finding, according to them, was that while the association between mental effort and adverse feelings was still significant, it was less pronounced in studies conducted in Asian countries compared with those in Europe or North America!

This fits with the general idea that the aversiveness of mental effort may depend on people's learning history. High school students in Asian countries tend to spend more time on schoolwork than their European or North American counterparts and may therefore learn to withstand higher levels of mental exertion early on in their lives.

More important is the real-world observation that, despite the aversive nature of mentally challenging tasks, people still voluntarily engage in them.

The Unpleasantness of Thinking: A Meta-Analytic Review of the Association Between Mental Effort and Negative Affect, Psychological Bulletin (2024). DOI: 10.1037/bul0000443

Physicists develop new method to combine conventional internet with the quantum internet

Researchers  have developed a new transmitter-receiver concept for transmitting entangled photons over an optical fiber. This breakthrough could enable the next generation of telecommunications technology, the quantum internet, to be routed via optical fibers. The quantum internet promises eavesdropping-proof encryption methods that even future quantum computers cannot decrypt, ensuring the security of critical infrastructure.

In their experiment, the researchers demonstrated that the entanglement of photons is maintained even when they are sent together with a laser pulse. The research results were published in Science Advances.

The physicists could change the colour of a laser pulse with a high-speed electrical signal so that it matches the colour of the entangled photons. This effect enables them to combine laser pulses and entangled photons of the same colour in an optical fiber and separate them again.

This effect could integrate the conventional internet with the quantum internet.

Their experiment shows how the practical implementation of hybrid networks can succeed.

 Philip Rübeling et al, Quantum and coherent signal transmission on a single-frequency channel via the electro-optic serrodyne technique, Science Advances (2024). DOI: 10.1126/sciadv.adn8907

Excessive use of botanicals like turmeric, green tea are harming  livers

Botanicals like turmeric, green tea and black cohosh may seem benign, but their overuse is being increasingly linked to liver injury.

New research suggests that thousands are using at least one of the several leading botanicals. Many are ending up in hospitals for liver toxicity, researchers report.

Because there's almost no  regulatory oversight over botanicals, chemical tests of products linked to liver crises show frequent discrepancies between product labels and detected ingredients.

The researchers focused on the use of six of the most popular botanicals: Turmeric, green tea extract, the Garcinia cambodgia plant, black cohosh, red yeast rice and ashwagandha.

Millions of adults regularly take turmeric supplements, often with the notion that it can ease pain or arthritis. Unfortunately, "multiple randomized clinical trials have failed to demonstrate any efficacy of turmeric-containing products in osteoarthritis," and overdoing it on turmeric has been linked to serious liver toxicity, the researchers said.

Likewise, millions of  adults are estimated to be taking another potential liver toxin, green tea extract, usually to help boost energy and aid in weight loss.

But again, "multiple studies have failed to demonstrate any objective evidence of weight loss and sustained improvement in mood or energy levels" with products containing the active ingredients in green tea extract, the research  team noted.

Other claims, many unfounded, are made for other botanicals: Garcinia cambodgia is touted for weight loss, black cohosh for easing hot flashes and ashwagandha to help build muscle. But scientists noted that consumers may be overdosing on botanicals, or getting misled by labels that don't reflect the actual ingredients in their supplements. That may be leading to more users ending up in the ER.

Part 1

According to a US national database, cases of liver toxicity linked to botanical use, some severe or even fatal, nearly tripled between 2004 and 2014—from 7% of cases to 20%. Use of turmeric, green tea extract, Garcinia cambodgia were often implicated. Another study found such cases rising from 12.5% of liver toxicity cases in 2007 to 21.1% by 2015.
Who's using these botanicals? According to the new study, the most common consumer is an older (average age about 52) white (75% of users) female (57%), who was typically well-off.

People taking botanicals were more likely to be battling some kind of chronic illness, such as arthritis, thyroid disorders or cancer, compared to folks not using the supplements.
In two-thirds of cases, people took a botanical while also taking a prescription medicine, the study found. Because of the danger of drug interactions and the threat to liver health, it's crucial that botanical users inform their doctors, the research group said.
When botanicals are overused, the damage to the liver "can not only be severe, leading to hepatocellular [liver] injury with jaundice, but also fatal, leading to death or liver transplantation," the research team warned.

A prior study found that the number of liver transplants required due to botanical overuse jumped by 70% between 2009 and 2020.

 Alisa Likhitsup et al, Estimated Exposure to 6 Potentially Hepatotoxic Botanicals in US Adults, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.25822

Part 2

This Super-Black Material Made of Wood Can Absorb 99.3% of Light

A new super-black wood-based material has been created that absorbs more than 99 percent of the light that hits it. 

Researchers were working on water-repelling technologies for wood, using high-energy plasma gas – and noticed that the application of the gas turned the ends of wood cells completely black. Further examination revealed the incredible light absorption properties of the new super-black material.

The researchers  named their new material Nxylon.

Nxylon's composition combines the benefits of natural materials with unique structural features, making it lightweight, stiff and easy to cut into intricate shapes.

The material has a velvety appearance, its inventors report. The plasma treatment actually changes the tiny structures on the surface of the wood, introducing indentations that help to capture light and minimize any reflections.

Indeed, when a gold alloy was applied to the material, it remained black. This shows that the structure of the wood has changed – this isn't just an extra coating, but a reconfiguration of the fundamentals of the material.

Super-black materials are valuable in industries like astronomy, solar energy, and optics, where they help devices function more accurately or efficiently by reducing unwanted light reflection. For example, super-black materials can reduce glare and improve clarity on telescopes.

https://onlinelibrary.wiley.com/doi/10.1002/adsu.202400184

'Cool paint' for cars to keep drivers cooler

Car companies are trying  "cool paint" to keep people inside vehicles cooler, although the coating is six times thicker, making commercialization still a challenge.

The vehicles with the special paint looked like ordinary cars, but felt much cooler to the touch.

The cool paint lowered the cars' roof-panel temperature by 12 degrees Celsius (22 degrees Fahrenheit) and the interiors by 5 C (9 F).

Cooling materials are already widely used in buildings and other items. Cooler cars can reduce use of air-conditioning and relieve the toll from heat on engines and electric vehicle batteries.

They have  also been experimenting with paint that delivers lower cabin temperatures, mostly focusing on colours that refract the sun's rays.

The cool paint reflects sunlight better and also creates electromagnetic waves that block the rays, redirecting energy away from vehicles.

Source: Various news agencies

 How our brain decides what to do

 What exactly happens in our brain when we make a decision has been a mystery till now. But researchers  have found the solution. They have deciphered which brain chemical and which nerve cells mediate this decision: the messenger substance orexin and the neurons that produce it.

These neuroscientific fundamentals are relevant because many people don't take good decisions like getting enough exercise because they don't find it easy to decide. Most of us have probably already decided once or even several times to skip exercising in favor of one of the numerous alternative temptations of daily life. According to the World Health Organization, 80% of adolescents and 27% of adults don't get enough exercise. And obesity is increasing at an alarming rate not only among adults but also among children and adolescents.

Despite these statistics, many people manage to resist the constantly present temptations and get enough exercise.

In their experiments with mice, the researchers were able to show that orexin plays a key role in taking decisions. It's one of over a hundred messenger substances that are active in the brain. Other chemical messengers, such as serotonin and dopamine, were discovered a long time ago and their role has largely been decoded. The situation for orexin is different: Researchers discovered it relatively late, around 25 years ago, and they are now clarifying its functions step by step.

In neuroscience, dopamine is a popular explanation till now  for why we choose to do some things but avoid others. This brain messenger is critical for our general motivation. However, our current knowledge about dopamine does not easily explain why we decide to exercise instead of eating. Our brain releases dopamine both when we eat and when we exercise, which does not explain why we choose one over the other.

To find out what does explain this, the researchers devised a sophisticated behavioral experiment for mice, which were able to choose freely from among eight different options in ten-minute trials. These included a wheel they could run on and a "milkshake bar" where they could enjoy a standard strawberry-flavored milkshake.

"Mice like a milkshake for the same reason people do: It contains lots of sugar and fat and tastes good.

In their experiment, the scientists compared different groups of mice: one made up of normal mice and one in which the mice's orexin systems were blocked, either with a drug or through genetic modification of their cells.

The mice with an intact orexin system spent twice as much time on the running wheel and half as much time at the milkshake bar as the mice whose orexin system had been blocked. Interestingly, however, the behavior of the two groups didn't differ in experiments in which the scientists only offered the mice either the running wheel or the milkshake.

This means that the primary role of the orexin system is not to control how much the mice move or how much they eat. Rather, it seems central to making the decision between one and the other, when both options are available. Without orexin, the decision was strongly in favor of the milkshake, and the mice gave up exercising in favour of eating.

researchers expect that orexin may also be responsible for this decision in humans; the brain functions involved here are known to be practically the same in both species.

The researchers are now trying to verify this  in humans too.

Part 1

This could involve examining patients who have a restricted orexin system for genetic reasons—this is the case in around one in two thousand people. These people suffer from narcolepsy (a sleeping disorder). Another possibility would be to observe people who receive a drug that blocks orexin. Such drugs are authorized for patients with insomnia.

If we understand how the brain arbitrates between food consumption and physical activity, we can develop more effective strategies for addressing the global obesity epidemic and related metabolic disorders.
Interventions could be developed to help overcome exercise barriers in healthy individuals and those whose physical activity is limited.

Orexin neurons mediate temptation-resistant voluntary exercise, Nature Neuroscience (2024). DOI: 10.1038/s41593-024-01696-2

Looking inside a microchip with 4 nanometer precision: New X-ray world record

Researchers  have used X-rays to look inside a microchip with higher precision than ever before. The image resolution of 4 nanometers marks a new world record. The high-resolution three-dimensional images of the type they produced will enable advances in both information technology and the life sciences.

The researchers  reported their findings in the current issue of the journal Nature.

Since 2010, the scientists have been developing microscopy methods with the goal of producing three-dimensional images in the nanometer range. In their current research, they have succeeded for the first time in taking pictures of state-of-the-art computer chips microchips with a resolution of 4 nanometers—a world record.

Instead of using lenses, with which images in this range are not currently possible, the scientists resort to a technique known as ptychography, in which a computer combines many individual images to create a single, high-resolution picture. Shorter exposure times and an optimized algorithm were key to significantly improving upon the world record they themselves set in 2017. For their experiments, the researchers used X-rays from the Swiss Light Source SLS at PSI.

Tomas Aidukas et al, High-performance 4-nm-resolution X-ray tomography using burst ptychography, Nature (2024). DOI: 10.1038/s41586-024-07615-6

What Your Nails Say About Your Health

https://youtu.be/PRftXdvENRw?si=VgUs4ne4n_eT2KL_

Domestication causes smaller brain size in dogs than in the wolf: Study challenges notion

A recent study, published in Biology Letters, challenges the long-held notion that domestication is the primary driver of reduced brain size in domesticated animals, specifically dogs.

Employing a phylogenetic comparative approach, researchers  show that the domesticated dog does not exhibit an exceptionally small brain relative to its body size compared to other canid species, suggesting that  domestication is not as unique an evolutionary force as previously thought.

The prevailing belief has been that domestication leads to a significant reduction in brain size due to relaxed selection pressures, such as reduced need for foraging, mating competition, and predator avoidance.

This phenomenon is thought to be a result of the decreased necessity for metabolically costly brain tissue in a domesticated environment. While domesticated dogs show a substantial decrease in brain size compared to their wild ancestor, the gray wolf (Canis lupus), this study aimed to determine if this reduction is exceptional when viewed in a broader phylogenetic context.

Researchers analyzed brain and body size data for 25 canid species, including ancient dog breeds that are genetically closer to the ancestral domesticated dog.

Their phylogenetic predictions and allometric regressions showed that the reduction in brain size in domesticated dogs is not an unambiguous evolutionary singularity. The observed brain size in dogs fell within the expected range for most ancient breeds used in the study, suggesting that domestication is not uniquely influential in reducing brain size among canids.

Interestingly, the study found that the common raccoon dog (Nyctereutes procyonoides), which hibernates, is a more pronounced outlier in terms of brain size reduction. Hibernation, associated with prolonged periods of low metabolic activity and food scarcity, is hypothesized to constrain brain size evolution due to the high energy demands of large brains.

Part 1

The raccoon dog's significantly smaller brain size supports this hypothesis, highlighting that factors other than domestication, such as ecological adaptations like hibernation, can also drive reductions in brain size.

The study concludes that while domestication does contribute to brain size reduction in dogs, it should not be overemphasized as a uniquely powerful evolutionary force.

The findings suggest that other ecological and evolutionary pressures can similarly affect brain size and can mediate extreme variations in non-domesticated species as well. A more balanced and less human-focused perspective could refine our understanding of the complex interplay between domestication and brain size evolution in mammals.

 László Zsolt Garamszegi et al, The reduction in relative brain size in the domesticated dog is not an evolutionary singularity among the canids, Biology Letters (2024). DOI: 10.1098/rsbl.2024.0336 , royalsocietypublishing.org/doi … .1098/rsbl.2024.0336

Part 2

Modern aircraft emit less carbon than older aircraft, but their contrails may do more environmental harm

Modern commercial aircraft flying at high altitudes create longer-lived planet-warming contrails than older aircraft, a new study has found.

The result means that although modern planes emit less carbon than older aircraft, they may be contributing more to climate change through contrails.

The study highlights the immense challenges the aviation industry faces to reduce its impact on the climate. The new study also found that private jets produce more contrails than previously thought, potentially leading to outsized impacts on climate warming.

Contrails, or condensation trails, are thin streaks of cloud created by aircraft exhaust fumes that contribute to global warming by trapping heat in the atmosphere.

While the exact warming effect of contrails is uncertain, scientists think it is greater than warming caused by carbon emissions from jet fuel.
Published in Environmental Research Letters, the study used machine learning to analyze satellite data on more than 64,000 contrails from a range of aircraft flying over the North Atlantic Ocean.

Modern aircraft that fly at above 38,000 feet (about 12km), such as the Airbus A350 and Boeing 787 Airliners, create more contrails than older passenger-carrying commercial aircraft, the study found.

To reduce jet fuel consumption, modern aircraft are designed to fly at higher altitudes where the air is thinner with less aerodynamic drag, compared to older commercial aircraft, which usually fly at slightly lower altitudes (around 35,000ft/11km).

This means these higher-flying aircraft create less carbon emissions per passenger. However, it also means they create contrails that take longer to dissipate—creating a warming effect for longer and a complicated trade-off for the aviation industry.

Part 1

It's common knowledge that flying is not good for the climate. However, most people do not appreciate that contrails and jet fuel carbon emissions cause a double-whammy warming of the climate.
This study throws a spanner in the works for the aviation industry. Newer aircraft are flying higher and higher in the atmosphere to increase fuel efficiency and reduce carbon emissions. The unintended consequence of this is that these aircraft flying over the North Atlantic are now creating more, longer-lived, contrails, trapping additional heat in the atmosphere and increasing the climate impact of aviation.
This finding reflects the challenges the aviation industry faces when reducing its climate impact.
The study did confirm a simple step that can be taken to shorten the lifetime of contrails: Reduce the amount of soot emitted from aircraft engines, produced when fuel burns inefficiently.

Modern aircraft engines are designed to be cleaner and typically emit fewer soot particles, which cuts down the lifetime of contrails.

While other studies using models have predicted this phenomenon, the study published today is the first to confirm it using real-world observations.
Even higher in the sky, the researchers found that private jets create contrails more often than previously thought—adding to concerns about the excessive use of these aircraft by the super-rich.

Despite being smaller and using less fuel, private jets create similar contrails to much larger commercial aircraft, the analysis found.
Private jets fly higher than other planes, more than 40,000 feet above earth where there is less air traffic. However, like modern commercial aircraft creating more contrails compared to lower-flying older commercial aircraft, the high altitudes flown by private jets means they create outsized contrails.

 Operational differences lead to longer lifetimes of satellite detectable contrails from more fuel efficient aircraft, Environmental Research Letters (2024). DOI: 10.1088/1748-9326/ad5b78

Part 2

Why your best friends' genes matter

"Choose your friends wisely, no scientifically". Because ....

A study by researchers shows that your best friend's traits can rub off on you—especially ones that are in their genes.

The genetic makeup of adolescent peers may have long-term consequences for individual risk of drug and alcohol use disorders, depression and anxiety, the groundbreaking study has found.

Peers' genetic predispositions for psychiatric and substance-use disorders are associated with an individual's own risk of developing the same disorders in young adulthood.

The data of this study exemplifies the long reach of social genetic effects.

Socio-genomics—the influence of one person's genotype on the observable traits of another—is an emerging field of genomics. Research suggests that peers' genetic makeup may influence health outcomes of their friends.

In the studies conducted, even when controlling for factors such as the target individuals' own genetic predispositions and family socioeconomic factors, the researchers found a clear association between peers' genetic predispositions and target individuals' likelihood of developing a substance use or psychiatric disorder. The effects were stronger among school-based peers than geographically defined peers.

Within school groups, the strongest effects were among upper secondary school classmates, particularly those in the same vocational or college-preparatory track between ages 16 and 19. Social genetic effects for school-based peers were greater for drug and alcohol use disorders than major depression and anxiety disorder.

More research is needed to understand why these connections exist. 

The most obvious explanation for why peers' genetic predispositions might be associated with our own well-being is the idea that our peers' genetic predispositions influence their phenotype, or the likelihood that peers are also affected by the disorder.

This research also underscores the importance of disrupting processes and risks that extend for at least a decade after attendance in school. Peer genetic influences have a very long reach.

Peer Social Genetic Effects and the Etiology of Substance Use Disorders, Major Depression, and Anxiety Disorder in a Swedish National Sample, American Journal of Psychiatry (2024). DOI: 10.1176/appi.ajp.20230358

Researchers show that pesticide contamination is more than apple-skin deep

Pesticides and herbicides are critical to ensuring food security worldwide, but these substances can present a safety risk to people who unwittingly ingest them. Protecting human health, therefore, demands sensitive analytical methods to identify even trace levels of potentially harmful substances. Now, researchers reporting in Nano Letters have developed a high-tech imaging method to detect pesticide contamination at low levels, and its application on fruits reveals that current food safety practices may be insufficient.

The analytical method called surface-enhanced Raman spectroscopy (SERS) is gaining popularity as a nondestructive method for detecting chemicals from modern farming on produce. With SERS, metal nanoparticles or nanosheets are used to amplify the signals created by molecules when they are exposed to a Raman laser beam. The patterns created by the metal-enhanced scattered light serve as molecular signatures and can be used to identify small amounts of specific compounds.

In tests of the silver-embedded membrane for food safety applications, the researchers sprayed the pesticides thiram and carbendazim, alone or together, onto apples, air-dried the fruits and then washed them to mimic everyday practices. When they laid their membrane over the apples, SERS detected pesticides on the apples, even though the chemicals were present at low concentrations. The team was also able to clearly resolve scattered-light signatures for each pesticide on apples sprayed with both thiram and carbendazim, as well as detect pesticide contamination through the fruit's peel and into the outermost layer of pulp.

But the pigmented skin of apple is very important.  A raw apple with skin contains up to 332% more vitamin K, 142% more vitamin A, 115% more vitamin C, 20% more calcium, and up to 19% more potassium than a peeled apple does.

The peel of 1 apple will contain about 8.4 mg of vitamin C and 98 IU of vitamin A. When eating apples, if you peel them off, the amount of this vitamin will decrease. down to 6.4 mg of Vitamin C and 61 IU of Vitamin A.

You can't remove them without severely effecting the nutrient quality of the fruits.

However, these results suggest that washing alone could be insufficient to prevent pesticide ingestion and that peeling would be required to remove potential contamination in the skin and outer pulp, the researchers say. Beyond apples, they also used the SERS membrane system to detect pesticides on cucumbers, shrimp, chili powder and rice.

But Cellulose Surface Nanoengineering for Visualizing Food Safety, Nano Letters (2024). DOI: 10.1021/acs.nanolett.4c01513 , pubs.acs.org/doi/abs/10.1021/acs.nanolett.4c01513

Bacterial gut diversity improves the athletic performance of racehorses

The composition of gut bacteria of thoroughbred racehorses at one month old can predict their future athletic performance, according to a new study. 

In the study, foals with lower bacterial diversity at 28 days old also had a significantly increased risk of respiratory disease later in life.

This study is published in the journal Scientific Reports.

Researchers from Surrey's School of Veterinary Medicine and School of Bioscience 

investigated the composition of gut bacteria in thoroughbred foals bred for flat racing and its impact on their long-term health and athletic performance.

To investigate this, 438 fecal samples from 52 foals were analyzed, and respiratory, gastrointestinal, orthopedic and soft-tissue health issues were tracked from birth to age three. In addition, the team analyzed information regarding finishing position, official rating, and total prize money earnings as measures of athletic performance.

Minimizing the risk of disease and injury is important for the welfare of racehorses, and maximizing their athletic potential is important for their owners. Researchers have now found that gut health, in particular the health of gut bacterial communities very early in life, exerts a profound and enduring impact on racehorse health and performance.

Researchers found that the athletic performance of the foals was positively associated with higher fecal bacterial diversity at one month old. They identified that a higher abundance of the bacteria Anaeroplasmataceae was associated with a higher official rating (an evaluation of a horse based on its past performances), and increased levels of Bacillaceae at 28 days old were linked to higher race placings.

The team also investigated the long-term impact of foals receiving antibiotics during the first month of life. It was found that these foals had significantly lower fecal bacterial diversity at 28 days old than other foals who did not receive such treatments. Further analysis revealed that these foals won significantly lower prize money (an indicator of athletic performance) in their subsequent racing careers. In addition, foals who received antibiotics during their first 28 days of life had a significantly increased rate of developing a respiratory disease compared to their counterparts.

Interestingly, researchers also identified that low gut bacterial diversity in early life is associated with an increased risk of soft-tissue and orthopedic issues developing later in life. Researchers believe that the health impacts of low gut bacterial diversity in early life are likely to be related to immunological priming.

Work is currently underway to develop novel probiotics that will enhance the gut health of foals in early life and to investigate how antibiotics can be used while preserving gut health.

DNA fragments help detect kidney organ rejection

Findings from a study published in Nature Medicine show that donor-derived cell-free DNA (dd-cfDNA), also called liquid biopsy, has the potential for early detection of kidney transplant rejection.

The international study enrolled a diverse population of nearly 3,000 kidney transplant recipients—both adult and pediatric—from 14 transplantation centers in Europe and the U.S. The Department of Pediatrics at Washington University School of Medicine in St. Louis contributed one of the two pediatric datasets involved in the study.
When cells undergo apoptosis or necrosis, they release small fragments of DNA, known as cell-free DNA (cf-DNA), into the bloodstream. In inflammation associated with transplant rejection, dying cells release donor-derived cell-free DNA (dd-cfDNA). Researchers found those dd-cfDNA levels were strongly correlated with different types of transplant rejection, including antibody-mediated rejection, T cell-mediated rejection and mixed rejection. The study found similar accuracy in children and adults.

Often unnecessary and invasive graft biopsies are currently considered the "gold standard" in diagnosing transplant rejection, but dd-cfDNA could provide a non-invasive, accurate biomarker to reduce the need for biopsy.

While biopsies will continue as the method of rejection diagnosis, dd-cfDNA may improve early rejection diagnosis and enhance the care of kidney transplant recipients.

Olivier Aubert et al, Cell-free DNA for the detection of kidney allograft rejection, Nature Medicine (2024). DOI: 10.1038/s41591-024-03087-3

Processing traumatic memories during sleep leads to changes in the brain associated with improvement in PTSD symptoms

Currently, the first-choice treatment for PTSD is exposure-based psychotherapy, where therapists help rewire the emotions associated with the traumatic memory in the patient's brain, shifting from fear and arousal to a more neutral response.

PTSD is a mental health disorder that can occur after experiencing or witnessing a traumatic event. People with PTSD may experience flashbacks, nightmares, heightened vigilance, hyper-arousal, and mood and sleep problems. Currently available treatments for PTSD include eye movement desensitization and reprocessing (EMDR), where therapists guide patients through their traumatic memories while using a moving light or clicking sounds to distract them.

However, up to 50% of patients fail to respond well to this treatment.

EMDR has shown positive results, but  that success is low and dropping out from the treatment program is common among patients because revisiting traumatic memories is emotionally demanding.

In a study published on August 7 in Current Biology, scientists show for the first time that reactivating therapeutically-altered memories during sleep leads to more brain activity related to memory processing, which is associated with a reduction in PTSD symptoms.

Sleep provides a unique opportunity to enhance the memory of newly formed emotional reactions to traumatic events. During sleep, the brain focuses on consolidating memories and storing information for the long term.

Previous research has shown that if someone forms a new memory in the presence of an experimentally administered sound or scent, exposing them to the sound or scent while they sleep can improve their ability to recall that memory after waking up. This memory-enhancement technique is called targeted memory reactivation (TMR).

TMR has no negative effects on these patients. None of the patients reported more nightmares or worsened sleep after TMR.

Many psychiatric disorders, such as phobias, anxiety disorders, and addiction, are also related to maladaptive memories. This new work can inspire future research to explore the beneficial effects of TMR in treating other conditions.

Targeted memory reactivation to augment treatment in post-traumatic stress disorder, Current Biology (2024). DOI: 10.1016/j.cub.2024.07.019. www.cell.com/current-biology/f … 0960-9822(24)00922-9

Nanomaterials may enhance plant tolerance to high soil salt levels

Soil salt concentrations above the optimal threshold for plant growth can threaten global food security by compromising agricultural productivity and crop quality. An analysis published in Physiologia Plantarum has examined the potential of nanomaterials—which have emerged over the past decade as a promising tool to mitigate such "salinity stress"—to address this challenge.

Nanomaterials, which are tiny natural or synthetic materials, can modulate a plant's response to salinity stress through various mechanisms, for example by affecting the expression of genes related to salt tolerance or by enhancing physiological processes such as antioxidant activities.
When investigators assessed 495 experiments from 70 publications related to how different nanomaterials interact with plants under salinity stress, they found that nanomaterials enhance plant performance and mitigate salinity stress when applied at lower dosages. At higher doses, however, nanomaterials are toxic to plants and may even worsen salinity stress.

Also, plant responses to nanomaterials vary across plant species, plant families, and nanomaterial types.

Meta-analysis of nanomaterials and plants interaction under salinity stress, Physiologia Plantarum (2024). DOI: 10.1111/ppl.14445

Scientists uncover hidden forces causing continents to rise

Scientists have answered one of the most puzzling questions in plate tectonics: how and why "stable" parts of continents gradually rise to form some of the planet's greatest topographic features?

They have found that when tectonic plates break apart, powerful waves are triggered deep within the Earth that can cause continental surfaces to rise by over a kilometer.
Their findings help resolve a long-standing mystery about the dynamic forces that shape and connect some of the Earth's most dramatic landforms—expansive topographic features called 'escarpments' and 'plateaus' that profoundly influence climate and biology.

The new research examined the effects of global tectonic forces on landscape evolution over hundreds of millions of years. The findings are published Aug 8 in the journal Nature.

The research  results help explain why parts of the continents previously thought of as "stable" experience substantial uplift and erosion, and how such processes can migrate hundreds or even thousands of kilometers inland, forming sweeping elevated regions known as plateaus, like the Central Plateau of South Africa.

The researchers  discovered that when continents split apart, the stretching of the continental crust causes stirring movements in Earth's mantle (the voluminous layer between the crust and the core).

This process can be compared to a sweeping motion that moves towards the continents and disturbs their deep foundations.

The team noticed an interesting pattern: the speed of the mantle "waves" moving under the continents in their simulations closely matched the speed of major erosion events that swept across the landscape in Southern Africa following the breakup of the ancient supercontinent Gondwana.

The scientists pieced together evidence to propose that the Great Escarpments originate at the edges of ancient rift valleys, much like the steep walls seen at the margins of the East African Rift today. Meanwhile, the rifting event also sets about a "deep mantle wave" that travels along the continent's base at about 15–20 kilometers per million years.

This wave convectively removes layers of rock from the continental roots.

Much like how a hot-air balloon sheds weight to rise higher, this loss of continental material causes the continents to rise—a process called isostasy.

Part 1

Building on this, the team modeled how landscapes respond to this mantle-driven uplift. They found that migrating mantle instabilities give rise to a wave of surface erosion that lasts tens of millions of years and moves across the continent at a similar speed. This intense erosion removes a huge weight of rock that causes the land surface to rise further, forming elevated plateaus.
Their landscape evolution models show how a sequence of events linked to rifting can result in an escarpment as well as a stable, flat plateau, even though a layer of several thousands of meters of rocks has been eroded away.
The team's study provides a new explanation for the puzzling vertical movements of cratons far from the edges of continents, where uplift is more common.
The team has concluded that the same chain of mantle disturbances that trigger diamonds to quickly rise from Earth's deep interior also fundamentally shape continental landscapes, influencing a host of factors from regional climates and biodiversity to human settlement patterns.

Thomas Gernon, Co-evolution of craton margins and interiors during continental break-up, Nature (2024). DOI: 10.1038/s41586-024-07717-1. www.nature.com/articles/s41586-024-07717-1

Part 2

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Microbes conquer the next extreme environment: Your microwave

Since the industrial revolution, microbes have successfully colonized one novel type of habitat after another: for example, marine oil spills, plastic floating in the oceans, industrial brownfields, and even the interior of the International Space Station.

However, it turns out that one extreme environment harboring a specialized community of highly adapted microbes is much closer to home: inside microwaves. This finding has now been reported for the first time by researchers  in a study in Frontiers in Microbiology. It's not only important from the perspective of hygiene, but could also inspire biotechnological applications—if the strains found inside microwaves can be put to good use in industrial processes that require especially hardy bacteria.

The research results reveal that domestic microwaves have a more 'anthropized' microbiome, similar to kitchen surfaces, while laboratory microwaves harbour bacteria that are more resistant to radiation.

Researchers sampled microbes from inside 30 microwaves: 10 each from single-household kitchens, another 10 from shared domestic spaces--for example, corporate centers, scientific institutes, and cafeterias--and 10 from molecular biology and microbiology laboratories. The aim behind this sampling scheme was to see if these microbial communities are influenced by food interactions and user habits.

The team used two complementary methods to inventorize the microbial diversity: next-generation sequencing and cultivation of 101 strains in five different media.

In total, the researchers found 747 different genera within 25 bacterial phyla. The most frequently encountered phyla were Firmicutes, Actinobacteria, and especially Proteobacteria.

They found that the composition of the typical microbial community partly overlapped between shared domestic and single-household domestic microwaves, while laboratory microwaves were quite different. The diversity was lowest in single-household microwaves, and highest in laboratory ones.

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However, it was also similar to the microbiome in an industrial habitat: namely, on solar panels. The authors proposed that the constant thermal shock, electromagnetic radiation, and desiccation in such highly irradiated environments has repeatedly selected for highly resistant microbes, in the same manner as in microwaves.

For both the general public and laboratory personnel, the researchers recommend regularly disinfecting microwaves with a diluted bleach solution or a commercially available disinfectant spray. In addition, it is important to wipe down the interior surfaces with a damp cloth after each use to remove any residue and to clean up spills immediately to prevent the growth of bacteria.

The microwave bacteriome: biodiversity of domestic and laboratory microwave ovens, Frontiers in Microbiology (2024). DOI: 10.3389/fmicb.2024.1395751

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Lens-free fluorescence instrument detects deadly microorganisms in drinking water

Researchers have shown that a fluorescence detection system that doesn't contain any lenses can provide highly sensitive detection of deadly microorganisms in drinking water. With further development, the new approach could provide a low-cost and easy-to-use way to monitor water quality in resource-limited settings such as developing countries or areas affected by disasters.

It could also be useful when water safety results are needed quickly, such as for swimming events, a concern highlighted during the Paris Olympics.

Current methods used to assess microbial contamination in water require culturing the water samples and then quantifying harmful bacteria. This can take over 18 hours, making it impractical when immediate confirmation of water safety is needed. This is also a key reason why water surveillance is ineffective in developing countries, where the required skilled human resources, infrastructure and reagents are not readily available.

The  new water monitoring fluorometer can detect fluorescent proteins from bacteria in water down to levels of less than one part per billion, without using any lenses.

This sensitivity meets the World Health Organization's criteria for detecting fecal contamination in drinking water.

During development, the researchers closely examined the fundamentals of optical signal generation in applications like water quality monitoring.

They discovered that while optical lenses are commonly used in devices such as cameras, microscopes and telescopes, these optical components often reduce performance for practical situations that don't require images.

This was an important finding because lenses account for a significant share of the costs of optical systems and their bulk and weight make it difficult to create practical portable devices.

The new analysis revealed that using a light source, detectors and sample sizes that are all as large and as close to each other as possible produces a stronger signal, leading to better performance for water quality monitoring.

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