Mighty proteins keep DNA regions close for longer

New work by researchers shows that key proteins help to stabilize the interaction between otherwise highly dynamic DNA structures. The findings shed light onto how the complex folds that help to fit nearly two meters of DNA into the cell’s nucleus influence important biological processes.

World-First Trial Transfusing Lab-Grown Red Blood Cells Begins

A trial testing how long a teaspoon-sized transfusion of lab-grown red blood cells lasts in the body could revolutionize clinical care for people with blood disorders who require regular blood transfusions.

The world-first trial, underway in the UK, is studying whether red blood cells made in the laboratory last longer than blood cells made in the body. Although the trial is only small, it represents a "huge stepping stone for manufacturing blood from stem cells.

To generate the transfusions, the team of researchers isolated stem cells from donated blood and coaxed them into making more red blood cells, a process that takes around three weeks.

In the past, researchers showed they could transfuse lab-grown blood cells back into the same donor they were derived from. This time, they have infused the manufactured cells into another compatible person – a process known as allogeneic transfusion.

Only two people have so far received the lab-made red cells under close monitoring and "no untoward side effects" have been reported by the clinical team, according to a statement released last month. At least another eight participants will receive two transfusions of 5 to 10 milliliters of blood, spaced at least four months apart. One transfusion will contain red blood cells provided by a donor; the other will have lab-grown red cells derived from stem cells from the same donor. Once transfused into the bodies of healthy volunteers, the manufactured cells – which are labeled with a tracer dye – will be tracked as they whiz through the body's circulatory system, until they are worn out, gobbled up, and recycled. The lab-grown blood cells are all freshly made from donated stem cells, whereas a typical blood donation contains a swirling mix of new and months-old blood cells, so the researchers are hopeful the manufactured cells will go the distance and last longer.

https://www.cam.ac.uk/research/news/first-ever-clinical-trial-under...

Pollination loss removes healthy foods from global diets, increases chronic diseases causing excess deaths

Inadequate pollination has led to a 3-5% loss of fruit, vegetable, and nut production and an estimated 427,000 excess deaths annually from lost healthy food consumption and associated diseases, including heart disease, stroke, diabetes, and certain cancers, according to research. It is the first study to quantify the human health toll of insufficient wild (animal) pollinators on human health.

A critical missing piece in the biodiversity discussion has been a lack of direct linkages to human health. This research establishes that loss of pollinators is already impacting health on a scale with other global health risk factors, such as prostate cancer or substance use disorders.

Increasing human pressure on natural systems is causing alarming losses in biodiversity, the topic of the COP 15 UN Biodiversity Conference currently taking place in Montreal. This includes 1-2% annual declines of insect populations, leading some to warn of an impending "insect apocalypse" in the coming decades. Key among insect species are pollinators, which increase yields of three-fourths of crop varieties and are critical to growing healthy foods like fruits, vegetables, and nuts. Changes in land-use, use of harmful pesticides, and advancing climate change threaten wild pollinators, imperiling human supply of healthy foods. The researchers used a model framework, which included empirical evidence from a network of hundreds of experimental farms across Asia, Africa, Europe and Latin America, that looked at "pollinator yield gaps" for the most important pollinator-dependent crops, to show how much crop loss was due to insufficient pollination. They then used a global risk-disease model to estimate the health impacts the changes in pollination could have on dietary risks and mortality by country. Additionally, they calculated the loss of economic value from lost pollination in three case study countries. The results showed that lost food production was concentrated in lower-income countries but that the health burden was greater in middle- and higher-income countries, where rates of non-communicable diseases are higher. The geographic distribution was somewhat unusual in that generally the health effects from global environmental change are centered among the poorest populations in regions such as South Asia and Sub-Saharan Africa. Here, middle-income countries with large populations—China, India, Indonesia, and Russia—suffered the greatest burden. The analysis also showed that lower-income countries lost significant agricultural income due to insufficient pollination and lower yields, potentially 10-30% of total agricultural value.

Strategies to protect wild pollinators are not just an environmental issue, but a health and economic one as well. This study shows that doing too little to help pollinators does not just harm nature, but human health as well.

Pollinator deficits, food consumption, and consequences for human health: a modeling study, Environmental Health Perspectives (2022). DOI: 10.1289/EHP10947

Discovery could explain why women are more likely to get Alzheimer's

Scientists  have found a clue to the molecular cause of Alzheimer's—a clue that may also explain why women are at greater risk for the disease.

In the study, reported on December 14, 2022, in Science Advances, the researchers found that a particularly harmful, chemically modified form of an inflammatory immune protein called complement C3 was present at much higher levels in the brains of women who had died with the disease, compared to men who had died with the disease. They also showed that estrogen—which drops in production during menopause—normally protects against the creation of this form of complement C3.

These new findings suggest that chemical modification of a component of the complement system helps drive Alzheimer's, and may explain, at least in part, why the disease predominantly affects women.

Hongmei Yang et al, Mechanistic insight into female predominance in Alzheimer's disease based on aberrant protein S-nitrosylation of C3, Science Advances (2022). DOI: 10.1126/sciadv.ade0764. www.science.org/doi/10.1126/sciadv.ade0764

Physics-Based Planning for Generalizable Assembly by Disassembly

Study finds higher levels of common diet-associated microbe elevates heart failure risk

New research  expands the link between what we eat and how the gut microbiome impacts our susceptibility to develop different diseases—in this case, how a specific gut microbe-generated byproduct is linked to heart failure risk.

Elevated levels of phenylacetylglutamine (PAG)—a byproduct created when microbes in the gut breakdown dietary protein—can be directly linked to both increased heart failure risk and severity, according to findings published in Circulation: Heart Failure.

The new findings improve researchers' understanding of how the gut microbiome, through PAG levels, are linked to cardiac disease risks, and suggest potential approaches to modify PAG-associated risks through interventions such as diet and beta blocker use.

Elevated PAG levels also were shown to correspond with types of heart failure. For example, elevated blood PAG was observed in subjects with heart failure with preserved ejection fraction, a condition where the heart muscle doesn't relax enough between beats and becomes too stiff, making it less able to fill and consequently pump blood.

Kymberleigh A. Romano et al, Gut Microbiota-Generated Phenylacetylglutamine and Heart Failure, Circulation: Heart Failure (2022). DOI: 10.1161/CIRCHEARTFAILURE.122.009972

Ina Nemet et al, A Cardiovascular Disease-Linked Gut Microbial Metabolite Acts via Adrenergic Receptors, Cell (2020). DOI: 10.1016/j.cell.2020.02.016

Immune surprise: Recently evolved alarm molecule drives inflammation

Scientists  have made an important breakthrough in understanding how inflammation is regulated. They have just discovered that a key immune alarm protein previously believed to calm down the immune response actually does the opposite.

Their work has numerous potential impacts, especially in the context of understanding and responding to autoimmune disorders and inflammation.

While our immune system serves a very important function protecting us from infection and injury, when immune responses become too aggressive this can lead to damaging inflammation, which occurs in conditions such as rheumatoid arthritis and psoriasis. Inflammation is triggered when our bodies produce "alarm proteins" (interleukins), which ramp up our defenses against infection and injury by switching on different components of our immune system.

Understanding how and when such alarm proteins are produced and how they activate our immune system has led to major breakthroughs in the treatment of many immune conditions.

Now, scientists  have found that Interleukin-37 has an unexpected function as an immune-activating molecule, as previous studies suggested that this interleukin instead served as an "off switch" for the immune system.

Prior to the new study, Interleukin-37 was thought to have immune-suppressive functions but how exactly it switched off inflammation was hotly debated. However, the scientists now report that, when activated in the correct way, Interleukin-37 displays potent pro-inflammatory activity.

Part 1

This pro-inflammatory impact was highly unexpected. Our work shows that the protein binds to an interleukin receptor in the skin that is known to play a key role in driving psoriasis. And, to add further intrigue to the story, this brings the total number of immune alarm molecules that signal via this particular interleukin receptor to four.

"Why there are so many interleukins that bind to the same receptor is a mystery, but if we were to speculate it may be because this receptor serves a very important sentinel function in our skin, and that one alarm protein may simply not be enough to respond to the many different infectious agents that our skin encounters. Our skin is the major barrier between our bodies and the outside world that microbes must breach if they are to gain entry to our bodies and, in many respects, represents the first line of defense in our immune systems."

As such, Interleukin-37 and other immune alarm  proteins may have evolved to become distinct variations on the same theme that enable our bodies to detect different types of infection by becoming activated by enzymes that are distinct to each infectious agent.

 Graeme P. Sullivan et al, Myeloid cell–derived proteases produce a proinflammatory form of IL-37 that signals via IL-36 receptor engagement, Science Immunology (2022). DOI: 10.1126/sciimmunol.ade5728. www.science.org/doi/10.1126/sciimmunol.ade5728

Part 2

From COVID-19 to the common cold: scientists identify broadly effective, infection-halting compound

Researchers have identified a compound that shows early promise at halting infections from a range of coronaviruses, including all variants of SARS-CoV-2 and the common cold. The findings, published this week in Molecular Biomedicine, reveal a potential path toward antiviral treatments that could be used against many different pathogens.

Beyond COVID-19, there are many different types of coronaviruses that can cause serious and sometimes fatal disease, and even more are likely to emerge in the future. 

The researchers credit the compound’s broad effectiveness to the unique way it works. Rather than targeting the virus itself, the compound targets a human cellular process that coronaviruses use to replicate.

Since viruses can’t reproduce on their own, they rely on protein-synthesis pathways in host cells to create copies of themselves. In the case of coronaviruses, they use a human enzyme called GSK3 beta that exists in all human cells.

Scientists found that coronaviruses hijack this human enzyme and use it to edit the protein that packs its genetic material. This compound blocks GSK3 beta, which in turn, stops the virus from reproducing and maturing its proteins.

The compound is part of a broader family of experimental drugs known as GSK3 inhibitors. Since the late 1990s, scientists across academia and industry have been studying GSK3 inhibitors for their potential as treatments for a number of diseases, including diabetes, Alzheimer’s and cancer.

By targeting this cellular pathway, rather than the virus itself, scientists see broad activity against multiple pathogens. We’re also acting on a pathway that is so far immune to changes between variants and different coronaviruses.

https://link.springer.com/article/10.1186/s43556-022-00111-1

Gold-based passive heating for eyewear

Study uncovers existing limitations in the detection of entanglement

Quantum entanglement is a process through which two particles become entangled and remain connected over time, even when separated by large distances. Detecting this phenomenon is of crucial importance for both the development of quantum technology and the study of quantum many-body physics.

Researchers  have recently carried out a study exploring the possible reasons why the reliable and efficient detection of entanglement in complex and "noisy" systems has often proved to be very challenging. Their findings, published in Physical Review Letters, hint at the existence of a trade-off between the effectiveness and efficiency of entanglement detection methods.

This new work showed that to observe entanglement on a large-scale, researchers must be able to control all interactions in a system with high precision and know almost all information about them. When there is a lot of uncertainty about the system, therefore, the probability of detecting its entanglement is very small, even if one is almost certain of its occurrence.

This proved that no entanglement detection protocols are both efficient and effective. This may help the design of entanglement detection protocols in the future.

Pengyu Liu et al, Fundamental Limitation on the Detectability of Entanglement, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.129.230503

Karol Życzkowski et al, Volume of the set of separable states, Physical Review A (2002). DOI: 10.1103/PhysRevA.58.883

Leonid Gurvits et al, Largest separable balls around the maximally mixed bipartite quantum state, Physical Review A (2002). DOI: 10.1103/PhysRevA.66.062311

Stanislaw J. Szarek, Volume of separable states is super-doubly-exponentially small in the number of qubits, Physical Review A (2005). DOI: 10.1103/PhysRevA.72.032304

Xi-Lin Wang et al, 18-Qubit Entanglement with Six Photons' Three Degrees of Freedom, Physical Review Letters (2018). DOI: 10.1103/PhysRevLett.120.260502

Developing antibiotics that target multiple-drug-resistant bacteria

Researchers have designed and synthesized analogs of a new antibiotic that is effective against multidrug-resistant bacteria, opening a new front in the fight against these infections.

Antibiotics are vital drugs in the treatment of a number of bacterial diseases. However, due to continuing overuse and misuse, the number of bacteria strains that are resistant to multiple antibiotics is increasing, affecting millions of people worldwide. The development of new antibacterial compounds that target multiple drug resistant bacteria is also an active field of research so that this growing issue can be controlled.

Scientists have been working on the development of new antibacterials. Their most recent research, published in the journal Nature Communications, details the development of a highly effective antibacterial compound that is effective against the most common multidrug-resistant bacteria.

 worked on a class of antibacterial compounds called sphaerimicins. These compounds block the function of a protein in the bacteria called MraY. MraY is essential for the replication of bacteria and plays a role in the synthesis of the bacterial cell wall; it is also not a target of currently available commercial antibiotics.

The team analyzed structures of sphaerimicin A by molecular modeling assisted by calculation, and designed and synthesized two analogs of sphaerimicin, SPM1 and SPM2. These analogs were found to be effective against Gram positive bacteria.

They then determined the structure of SPM1 bound to MraY. By studying this structure and comparing it to that of related antibacterial agents, they determined how to further simplify the molecules. They were successful in developing a simpler analog, SPM3, whose activity was similar to SPM1.

In addition to their effectiveness against MRSA and VRE, the SPMs were also effective against Mycobacterium tuberculosis, the bacteria that causes tuberculosis—and which has multidrug-resistant strains.

Satoshi Ichikawa et al, Synthesis of macrocyclic nucleoside antibacterials and their interactions with MraY, Nature Communications (2022). DOI: 10.1038/s41467-022-35227-z

**

Network neuroscience theory best predictor of intelligence, study finds

Scientists have laboured for decades to understand how brain structure and functional connectivity drive intelligence. A new analysis offers the clearest picture yet of how various brain regions and neural networks contribute to a person's problem-solving ability in a variety of contexts, a trait known as general intelligence, researchers report.

The study used "connectome-based predictive modeling" to compare five theories about how the brain gives rise to intelligence. 

To understand the remarkable cognitive abilities that underlie intelligence, neuroscientists look to their biological foundations in the brain. Modern theories attempt to explain how our capacity for problem-solving is enabled by the brain's information-processing architecture. A biological understanding of these cognitive abilities requires 'characterizing how individual differences in intelligence and problem-solving ability relate to the underlying architecture and neural mechanisms of brain networks'. Historically, theories of intelligence focused on localized brain regions such as the prefrontal cortex, which plays a key role in cognitive processes such as planning, problem-solving and decision-making. More recent theories emphasize specific brain networks, while others examine how different networks overlap and interact with one another.

Strong connections involve highly connected hubs of information-processing that are established when we learn about the world and become adept at solving familiar problems. Weak connections have fewer neural linkages but enable flexibility and adaptive problem-solving. Together, these connections provide the network architecture that is necessary for solving the diverse problems we encounter in life.

Part 1

One of the really interesting properties of the human brain is how it embodies a rich constellation of networks that are active even when we are at rest. These networks create the biological infrastructure of the mind and are thought to be intrinsic properties of the brain.

These include the frontoparietal network, which enables cognitive control and goal-directed decision-making; the dorsal attention network, which aids in visual and spatial awareness; and the salience network, which directs attention to the most relevant stimuli. Previous studies have shown that the activity of these and other networks when a person is awake but not engaged in a task or paying attention to external events "reliably predicts our cognitive skills and abilities".

With the cognitive tests and fMRI data, the researchers were able to evaluate which theories best predicted how participants performed on the intelligence tests.

We can systematically investigate how well a theory predicts general intelligence based on the connectivity of brain regions or networks that theory entails. This approach allowed the researchers to directly compare evidence for the neuroscience predictions made by current theories.

The researchers found that taking into account the features of the whole brain produced the most accurate predictions of a person's problem-solving aptitude and adaptability. This held true even when accounting for the number of brain regions included in the analysis.

The other theories also were predictive of intelligence, the researchers said, but the network neuroscience theory  outperformed those limited to localized brain regions or networks in a number of respects.

The findings reveal that "global information processing" in the brain is fundamental to how well an individual overcomes cognitive challenges.

Rather than originate from a specific region or network, intelligence appears to emerge from the global architecture of the brain and to reflect the efficiency and flexibility of systemwide network function. 

Investigating cognitive neuroscience theories of human intelligence: A connectome-based predictive modeling approach, Human Brain Mapping (2022). DOI: 10.1002/hbm.26164

Part 2

Three quarters of major observatories affected by light pollution

Researchers  have studied and compared the light pollution levels at major astronomical observatories across the world. The study shows that light is polluting the sky above most observatories and that immediate action is needed to decrease the amount of contamination coming from artificial light. The work was published in Monthly Notices of the Royal Astronomical Society.

The study presents the light pollution levels above almost 50 observatories across the globe, including the world's largest professional observatories, as well as smaller observatories for amateurs. The study utilizes a model of propagation of light in the Earth's atmosphere and applies it to night-time satellite data. Using additional light pollution indicators, beyond examining the traditional brightness directly overhead (i.e. at the zenith), reveals that the night sky at major observatory sites is more polluted than one may assume. The zenith is generally the less polluted, therefore darker, zone of the night sky, and is one of the indicators used to classify the sites in the study. The additional indicators are the average brightness at a 30° altitude above the horizon, the average brightness in the first 10° above the horizon, the overall average brightness across the sky, and the illuminance of the ground given by the artificial light coming from the night sky. These indicators, along with the overhead brightness, help to decipher how artificial light affects the night sky.

The key measure is the comparison with the natural sky brightness caused by airglow in the high atmosphere, and light originating from stars and the Milky Way. The study results show that only 7 of the 28 major astronomical observatory sites (sites that host a telescope with a diameter of 3 meters or more) have a zenith sky brightness with light pollution below the expected threshold of 1% of natural sky brightness, and so could be considered almost uncontaminated in that direction. This leaves the remaining 21 other major sites—three quarters of all the major observatories—all above this level. The lowest pointing direction of ground-based telescopes is around 30° above the horizon. Only one observatory of the 28 major sites has light pollution in that direction below the 1% level. A more relaxed 10% limit was set by the International Astronomical Union in the 1970s as the maximum allowable artificial brightness for major observatories. The new study shows that light pollution at two thirds of the ground based observatories in the study has now crossed this higher threshold.

Fabio Falchi et al, Light pollution indicators for all the major astronomical observatories, Monthly Notices of the Royal Astronomical Society (2022). DOI: 10.1093/mnras/stac2929

Human-caused emissions create new cloud-forming particles

Human activity is changing atmospheric chemistry—even in remote places—that could alter how and when clouds form.

That's the conclusion of a new study by scientists, which finds that at a laboratory on a mountaintop in Colorado, new aerosol particles are forming in the air on average every other day and that those particles, likely formed from gases emitted by nearby power plants, can grow until they're big enough for water to condense around, forming clouds.

The study draws an important scientific link, using newly developed statistical methods, that link aerosol growth to measured cloud condensation nuclei—which are the critical ingredients for accurately modeling the role of aerosols and clouds in climate change. 

 To form, clouds need something in the air, such as a speck of dirt or salt, around which to begin condensing water vapor. These somethings, about a tenth of the diameter of spider silk, are particles called "cloud condensation nuclei."

It's known that increased aerosols in the atmosphere lead to more cloud formation, and more reflective clouds. But it's not known whether new aerosol particles, much smaller than cloud condensation nuclei and formed with human-caused emissions, can grow into cloud condensation nuclei. And it's also not known how to incorporate the relationship between aerosols and clouds in climate models. As you might imagine, clouds play a large role in the climate, reflecting solar energy and moving water from one place to another. So being able to realistically model those clouds could help increase the accuracy of the models forecasting changes in our climate.

Noah S. Hirshorn et al, Seasonal significance of new particle formation impacts on cloud condensation nuclei at a mountaintop location, Atmospheric Chemistry and Physics (2022). DOI: 10.5194/acp-22-15909-2022

New software based on artificial intelligence helps to interpret co...

More is not always better—sometimes, it's a problem. With highly complex data, which have many dimensions due to their numerous parameters, correlations are often no longer recognizable. Especially since experimentally obtained data are additionally disturbed and noisy due to influences that cannot be controlled.

Study finds birds build hanging-nests to protect offspring from nest invaders

A new study has found that birds build hanging-nests, particularly those with extended entrance tunnels, to help protect offspring against nest invaders like snakes and parasitic cuckoos.

Researchers examined the relationship between nest design and the length of time offspring spend in the nest before fledging across species of weaverbirds and icterids, two bird families renowned for their complex woven nests. They found that species building the most elaborate nests, particularly those with long entrance tunnels, produce offspring with longer developmental periods.

Nests with longer entrance tunnels are more effective at hindering access by nest invaders than shorter tunnels and thereby limits the exposure of developing offspring to nest invaders.

Researchers suggest that the complex structural features in these nests do indeed play a role in protecting offspring from predators and brood parasites. They find the consistency of these findings "striking" given that highly elaborate nests have evolved independently in the weaverbirds and icterids.

Sally Street et al, Convergent evolution of elaborate nests as structural defences in birds, Proceedings of the Royal Society B: Biological Sciences (2022). DOI: 10.1098/rspb.2022.1734. royalsocietypublishing.org/doi … .1098/rspb.2022.1734

The physical intelligence of ant and robot collectives

Researchers took inspiration from ants to design a team of relatively simple robots that can work collectively to perform complex tasks using only a few basic parameters.

Researchers use 3D bioprinting to create eye tissue

Scientists used patient stem cells and 3D bioprinting to produce eye tissue that will advance understanding of the mechanisms of blinding diseases. The research team from the National Eye Institute (NEI), part of the National Institutes of Health, printed a combination of cells that form the outer blood-retina barrier—eye tissue that supports the retina's light-sensing photoreceptors. The technique provides a theoretically unlimited supply of patient-derived tissue to study degenerative retinal diseases such as age-related macular degeneration (AMD).

We know that AMD starts in the outer blood-retina barrier. However, mechanisms of AMD initiation and progression to advanced dry and wet stages remain poorly understood due to the lack of physiologically relevant human models.

The outer blood-retina barrier consists of the retinal pigment epithelium (RPE), separated by Bruch's membrane from the blood-vessel rich choriocapillaris. Bruch's membrane regulates the exchange of nutrients and waste between the choriocapillaris and the RPE. In AMD, lipoprotein deposits called drusen form outside Bruch's membrane, impeding its function. Over time, the RPE break down leading to photoreceptor degeneration and vision loss.

Researchers combined three immature choroidal cell types in a hydrogel: pericytes and endothelial cells, which are key components of capillaries; and fibroblasts, which give tissues structure. The scientists then printed the gel on a biodegradable scaffold. Within days, the cells began to mature into a dense capillary network.

On day nine, the scientists seeded retinal pigment epithelial cells on the flip side of the scaffold. The printed tissue reached full maturity on day 42. Tissue analyses and genetic and functional testing showed that the printed tissue looked and behaved similarly to native outer blood-retina barrier. Under induced stress, printed tissue exhibited patterns of early AMD such as drusen deposits underneath the RPE and progression to late dry stage AMD, where tissue degradation was observed. Low oxygen induced wet AMD-like appearance, with hyperproliferation of choroidal vessels that migrated into the sub-RPE zone. Anti-VEGF drugs, used to treat AMD suppressed this vessel overgrowth and migration and restored tissue morphology.

Researchers  are using printed blood-retina barrier models to study AMD, and they are experimenting with adding additional cell types to the printing process, such as immune cells, to better recapitulate native tissue.

Kapil Bharti, Bioprinted 3D outer retina barrier uncovers RPE-dependent choroidal phenotype in advanced macular degeneration, Nature Methods (2022). DOI: 10.1038/s41592-022-01701-1. www.nature.com/articles/s41592-022-01701-1

Meta-optics: The disruptive technology you didn't see coming

Robots and autonomous cars will have eyes that see much more than the human eye is capable of, a review of the growing field of meta-optics has found.

Meta-optics is advancing science and technology far beyond the 3,000-year-old optical paradigm that we rely on for the visual human-machine interface, such as through cameras in our mobile phones, the lenses in microscopes, drones, and telescopes. Optical components are the technology bottleneck that meta-optics aims to transform, bringing the stuff of science-fiction stories into everyday devices. The field, which blossomed after the early 2000s thanks to the conceptualization of a material with negative refractive index that could form a perfect lens, has grown rapidly in the last five years and now sees around 3000 publications a year. This accelerating volume of research is impossible for scientists and technologists to navigate, which prompted Nature Photonics to commission a review from leaders in meta-optics research.

They found the field was on the verge of industrial disruption.

The biggest driver for the meta-optics field comes from integrating meta-optical elements and devices into optical systems, offering consumer optoelectronics applications. Importantly, meta-optical systems enable novel applications not conceivable before, adding to so-called Industry 4.0. Such applications include the Internet of Things, autonomous cars, wearable devices, augmented reality and remote sensing. The importance of the technology is shown by the large-scale investment from big industry players such as Apple, Google, and Samsung, who have been hiring graduates and investing in the field, especially to develop vision applications.

But the authors note that beyond vision, the non-traditional characteristics of meta-optics could also be used for light sails, LiFi and thermal management. These characteristics come from meta-optics' use of surfaces patterned with regular nanoscale structures, in contrast with the traditional optics of mirrors and lenses. The result is miniature components that scatter and manipulate light in ways that would have astounded Isaac Newton. The first commercial components using these properties are already on the market, with companies such as Metalenz, NILT technologies and Meta Materials Inc delivering flat metalenses, polarization imaging, microscopy and biosensing. These devices also enable access to properties of light that the human eye cannot detect—polarization and phase, for example, and even can be used to engineer, manipulate and quantum states of light, that could be employed for quantum imaging, sensing and communications.

Dragomir Neshev, Enabling smart vision with metasurfaces, Nature Photonics (2022). DOI: 10.1038/s41566-022-01126-4. www.nature.com/articles/s41566-022-01126-4

https://phys.org/news/2022-12-meta-optics-disruptive-technology-did...

Microplastics deposited on the seafloor have tripled in 20 years

The total amount of microplastics deposited on the bottom of oceans has tripled in the past two decades with a progression that corresponds to the type and volume of consumption of plastic products by society.

This is the main conclusion of a recent study.

Despite the seafloor being considered the final sink for microplastics floating on the sea surface, the historical evolution of this pollution source in the sediment compartment, and particularly the sequestration and burial rate of smaller microplastics on the ocean floor, is unknown. This new study, published in the journal Environmental Science and Technology, shows that microplastics are retained unaltered in marine sediments, and that the microplastic mass sequestered in the seafloor mimics the global plastic production from 1965 to 2016.

Specifically, the results show that, since 2000, the amount of plastic particles deposited on the seafloor has tripled and that, far from decreasing, the accumulation has not stopped growing mimicking the production and global use of these materials.

Researchers explains that the sediments analyzed have remained unaltered on the seafloor since they were deposited decades ago. This has allowed them to see how, since the 1980s, but especially in the past two decades, the accumulation of polyethylene and polypropylene particles from packaging, bottles and food films has increased, as well as polyester from synthetic fibers in clothing fabrics.

The amount of these three types of particles reaches 1.5mg per kilogram of sediment collected, with polypropylene being the most abundant, followed by polyethylene and polyester. Despite awareness campaigns  on the need to reduce single-use plastic, data from annual marine sediment records show that we are still far from achieving this. Policies at the global level in this regard could contribute to improving this serious problem.

The degradation status of the buried particles was investigated, and it was found that, once trapped in the seafloor, they no longer degrade, either due to lack of erosion, oxygen, or light.

Laura Simon-Sánchez et al, Can a Sediment Core Reveal the Plastic Age? Microplastic Preservation in a Coastal Sedimentary Record, Environmental Science & Technology (2022). DOI: 10.1021/acs.est.2c04264

Are elephants afraid of mice?

Mythbusters explore the myth of whether elephants are afraid of mice.

Male and Female Stem Cells Derived from One Donor in Scientific First

Studying otherwise identical XY, XX, X0, and XXY pluripotent stem cells will allow researchers to investigate sex-based differences in greater depth.

Scientists have developed a new line of stem cells—all derived from the same person—that can be used to study sex differences without the confounds of interpersonal genetic differences.

Human induced pluripotent stem cells (hiPSCs), which are cells taken from a person that are then reprogrammed to abandon their current roles and return to a stem cell–like state, have become valuable tools not only for therapeutic purposes but also for probing the genetic mechanisms underlying cell behavior and disease. However, findings drawn from stem cell studies may not be broadly applicable, as the fact that all cells in a given line share the same genetic sequence makes it difficult to generalize discoveries, especially when it comes to investigating potential sex differences.

That’s why a team of scientists set out to create a new platform for studying genetic sex differences. 

To develop such a model, the team obtained cells from a repository that had been taken from someone with an unusual case of Klinefelter syndrome, a rare genetic condition that affects roughly 1 in 500 boys in which they’re born with an extra copy of the X chromosome, resulting in an XXY genetic makeup. What made this person even more unusual—and ideal for Reubinoff’s vision—is that, in addition to the 47XXY cells characteristic of the condition, they also had a large number of 46XY cells, a phenomenon known as a mosaic phenotype. As the study, published on November 24 in Stem Cell Reports, describes, the variety of cells taken from the Klinefelter patient allowed the team to generate 46XX, 46XY, 45X0, and 47XXY hiPSCs that are otherwise genetically identical. This means that any observable differences among them—related, for example, to disease risk factors or response to a pharmaceutical—can almost definitely be attributed to genetic sex differences.

When you study individuals, and you compare males to females and you find differences, you cannot differentiate whether they stem from the chromosomal differences or hormonal differences. This model is unique because it allows you to differentiate between chromosomal effects and hormonal effects.

https://www.cell.com/stem-cell-reports/fulltext/S2213-6711(22)00513-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2213671122005136%3Fshowall%3Dtrue#%20

https://www.the-scientist.com/news-opinion/male-and-female-stem-cel...

Identifying pathways to slow cardiac aging

Cardiovascular disease is the leading cause of death worldwide, and is caused in part by age-related cardiac structural dysfunction. A team of bioengineers published a paper in Nature Aging on Dec. 22 that helps advance our understanding of how hearts age, and sheds light on a possible pathway to slow cardiac aging.

The researchers used fruit flies to show that Lamin C, a protein responsible for maintaining the structural integrity of heart cells' nuclei, declines as flies age. This study uncovered that Lamin decline is responsible for the age-induced structural remodeling in fruit fly hearts, and it could be a potential target to slow down, or even help reverse, cardiac aging in humans.

The team then quantified this change by segmenting and measuring nuclear stiffness with atomic force microscopy. This is when they discovered that cardiomyocyte nuclei stiffen during natural aging; after running a genetic anlysis, the researchers found that the expression of nuclear lamins decreases as flies age.

The team was able to verify that these results also applied to mice and primates. This indicates that a role for Lamins may apply to human heart aging as well, which could have tremendous therapeutic value, as targeting lamin-stimulating pathways could potentially help avoid this cardiac aging-related mechanical change.

Natalie J. Kirkland et al, Age-dependent Lamin changes induce cardiac dysfunction via dysregulation of cardiac transcriptional programs, Nature Aging (2022). DOI: 10.1038/s43587-022-00323-8

Researchers use quantum mechanics to see objects without looking at them

We see the world around us because light is being absorbed by specialized cells in our retina. But can vision happen without any absorption at all—without even a single particle of light? Surprisingly, the answer is yes.

Imagine that you have a camera cartridge that might contain a roll of photographic film. The roll is so sensitive that coming into contact with even a single photon would destroy it. With our everyday classical means there is no way  to know whether there's film in the cartridge, but in the quantum world it can be done. Anton Zeilinger, one of the winners of the 2022 Nobel Prize in Physics, was the first to experimentally implement the idea of an interaction-free experiment using optics.

Now, in a study exploring the connection between the quantum and classical worlds,  researchers have discovered a new and much more effective way to carry out interaction-free experiments. They used transmon devices—superconducting circuits that are relatively large but still show quantum behavior—to detect the presence of microwave pulses generated by classical instruments. Their research was recently published in Nature Communications.

Quantum coherence refers to the possibility that an object can occupy two different states at the same time—something that quantum physics allows for. However, quantum coherence is delicate and easily collapses, so it wasn't immediately obvious that the new protocol would work. To the research  team's pleasant surprise, the first runs of the experiment showed a marked increase in detection efficiency. They went back to the drawing board several times, ran theoretical models confirming their results, and double-checked everything. The effect was definitely there. They also also demonstrated that even very low-power microwave pulses can be detected efficiently using their protocol.

The experiment also showed a new way in which quantum devices can achieve results that are impossible for classical devices—a phenomenon known as quantum advantage. Researchers generally think that achieving quantum advantage will require quantum computers with many qubits, but this experiment demonstrated genuine quantum advantage using a relatively simpler setup.

Shruti Dogra et al, Coherent interaction-free detection of microwave pulses with a superconducting circuit, Nature Communications (2022). DOI: 10.1038/s41467-022-35049-z

Using an ethylene carbonate solvent with a sodium iodide salt to create a new kind of refrigerator

A pair of researchers  used a commonly known, naturally occurring phenomenon to build a new kind of environmentally safe refrigerator.

In their paper published in the journal Science, they describe how expanding on the idea of using salt to melt road ice to design and build a new kind of refrigerator.

For many years, people around the world have used salt to melt road ice to make travel easier. Though technically, the salt does not melt the ice, its dark color attracts heat, allowing the ice below it to melt, which than allows the salt to mix with the water. And it does not refreeze because the salt dramatically lowers the freezing point of the water.

It was on this part of the process that the researchers focused. They noted that a similar process could result in cooling a material simply by mixing it with sodium iodide (NaI) salt due to the phase transition. The second material in this case was an ethylene carbonate (EC) solvent. They further noted that repeatedly cooling a material should also cool the environment in which it is contained. And to make that happen, all they had to do was remove the salt, and then add it again.

The researchers call their process "ionocaloric" refrigeration, and built such a refrigerator to prove that it was viable. They started with a box and then added a mixing device to mix their two ingredients and another device that performed electrodialysis to remove the salt. Then tested the resulting device to determine if it would keep the temperature inside the box at a steady cool temperature, and if so, if it was more or less efficient than other refrigeration devices.

Their testing showed that their refrigerator was able to maintain a cool temperature and that it was approximately as efficient as refrigerators now on the market. The big advantage of the approach is that it does not emit any hydrofluorocarbons or other pollutants. They acknowledge that it does have one drawback—it takes quite a while for the mixed solution to cool.

Drew Lilley et al, Ionocaloric refrigeration cycle, Science (2022). DOI: 10.1126/science.ade1696

Emmanuel Defay, Cool it, with a pinch of salt, Science (2022). DOI: 10.1126/science.adf5114

Brown algae removes carbon dioxide from the air and stores it in slime

Brown algae take up large amounts of carbon dioxide from the air and release parts of the carbon contained therein back into the environment in mucous form. This mucus is hard to break down for other ocean inhabitants, thus the carbon is removed from the atmosphere for a long time, according to a new study.

Researchers reveal that the algal mucus called fucoidan is particularly responsible for this carbon removal and estimate that brown algae could thus remove up to 550 million tons of carbon dioxide from the air every year.

Algae take up carbon dioxide from the atmosphere and use the carbon to grow. They release up to a third of the carbon they absorb back into the seawater, for example in the form of sugary excretions. Depending on the structure of these excretions, they are either quickly used by other organisms or sink toward the seafloor.

Fucoidan made up about half of the excretions of the brown algae species the researchers studied, the so-called bladderwrack.

Fucoidan is a recalcitrant molecule. The fucoidan is so complex that it is very hard for other organisms to use it. No one seems to like it. As a result, the carbon from the fucoidan does not return to the atmosphere quickly. "This makes the brown algae particularly good helpers in removing carbon dioxide from the atmosphere in the long term—for hundreds to thousands of years.

Buck-Wiese, Hagen et al, Fucoid brown algae inject fucoidan carbon into the ocean, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2210561119. doi.org/10.1073/pnas.2210561119

New bacterial therapy approach to treat lung cancer

Lung cancer is one of the deadliest cancers  around the world. Many of the currently available therapies have been ineffective, leaving patients with very few options. A promising new strategy to treat cancer has been bacterial therapy, but while this treatment modality has quickly progressed from labouratory experiments to clinical trials in the last five years, the most effective treatment for certain types of cancers may be in combination with other drugs.

Researchers report that they have developed a preclinical evaluation pipeline for characterization of bacterial therapies in lung cancer models. Their new study, published December 13, 2022, by Scientific Reports, combines bacterial therapies with other modalities of treatment to improve treatment efficacy without any additional toxicity. This new approach was able to rapidly characterize bacterial therapies and successfully integrate them with current targeted therapies for lung cancer.

The team used RNA sequencing to discover how cancer cells were responding to bacteria at the cellular and molecular levels. They built a hypothesis on which molecular pathways of cancer cells were helping the cells to be resistant to the bacteria therapy. To test their hypothesis, the researchers blocked these pathways with current cancer drugs and showed that combining the drugs with bacterial toxins is more effective in eliminating lung cancer cells. They validated the combination of bacteria therapy with an AKT-inhibitor as an example in mouse models of lung cancer.

This new study describes an exciting drug development pipeline that has been previously unexplored in lung cancer—the use of toxins derived from bacteria.

The preclinical data presented in the manuscript provides a strong rationale for continued research in this area, thereby opening up the possibility of new treatment options for patients diagnosed with this lethal disease.

 Dhruba Deb et al, Design of combination therapy for engineered bacterial therapeutics in non-small cell lung cancer, Scientific Reports (2022). DOI: 10.1038/s41598-022-26105-1

Spontaneous baby movements are important for development of coordinated sensorimotor system

Some guts are better than others at harvesting energy, study shows

New research from the University of Copenhagen suggests that a portion of the Danish population has a composition of gut microbes that, on average, extracts more energy from food than do the microbes in the guts of their fellow Danes. The research is a step towards understanding why some people gain more weight than others, even when they eat the same.

Unfair as it, some of us seem to put on weight just by looking at a plate of Christmas cookies, while others can munch away with abandon and not gain a gram. Part of the explanation could be related to the composition of our gut microbes. This is according to new research conducted at the University of Copenhagen's Department of Nutrition, Exercise and Sports.

The research is published in the journal Microbiome.

Researchers studied the residual energy in the feces of 85 Danes to estimate how effective their gut microbes are at extracting energy from food. At the same time, they mapped the composition of gut microbes for each participant.

The results show that roughly 40% of the participants belong to a group that, on average, extracts more energy from food compared to the other 60%. The researchers also observed that those who extracted the most energy from food also weighed 10% more on average, amounting to an extra nine kilograms.

The results indicate that being overweight might not just be related to how healthily one eats or the amount of exercise one gets. It may also have something to do with the composition of a person's gut microbes.

Following the study, the researchers suspect that a portion of the population may be disadvantaged by having gut bacteria that are a bit too effective at extracting energy. This effectiveness may result in more calories being available for the human host from the same amount of food.

Jos Boekhorst et al, Stool energy density is positively correlated to intestinal transit time and related to microbial enterotypes, Microbiome (2022). DOI: 10.1186/s40168-022-01418-5

About gut bacteria:

• Everyone has a unique composition of gut bacteria—shaped by genetics, environment, lifestyle and diet.
• The collection of gut bacteria, called the gut microbiota, is like an entire galaxy in our gut, with a staggering 100 billion of them per gram of stool.
• Gut bacteria in the colon serve to break down food parts that our body's digestive enzymes can't, e.g., dietary fiber.
• Humans can be divided into three groups based on the presence and abundance of three main groups of bacteria that most of us have: B-type (Bacteroides), R-type (Ruminococcaceae) and P-type (Prevotella).

Brain area necessary for fluid intelligence identified

A team of researchers have mapped the parts of the brain that support our ability to solve problems without prior experience—otherwise known as fluid intelligence.

Fluid intelligence is arguably the defining feature of human cognition. It predicts educational and professional success, social mobility, health, and longevity. It also correlates with many cognitive abilities such as memory.

Fluid intelligence is thought to be a key feature involved in "active thinking"—a set of complex mental processes such as those involved in abstraction, judgment, attention, strategy generation and inhibition. These skills can all be used in everyday activities.

Despite its central role in human behavior, fluid intelligence remains contentious, with regards to whether it is a single or a cluster of cognitive abilities, and the nature of its relationship with the brain. To establish which parts of the brain are necessary for a certain ability, researchers must study patients in whom that part is either missing or damaged. Such "lesion-deficit mapping" studies are difficult to conduct owing to the challenge of identifying and testing patients with focal brain injury. Consequently, previous studies have mainly used functional imaging (fMRI) techniques—which can be misleading.

The new study investigated 227 patients who had suffered either a brain tumour or stroke to specific parts of the brain, using the Raven Advanced Progressive Matrices (APM): the best-established test of fluid intelligence. The test contains multiple choice visual pattern problems of increasing difficulty. Each problem presents an incomplete pattern of geometric figures and requires selection of the missing piece from a set of multiple possible choices. The researchers then introduced a novel "lesion-deficit mapping" approach to disentangle the intricate anatomical patterns of common forms of brain injury, such as stroke.

Their approach treated the relations between brain regions as a mathematical network whose connections describe the tendency of regions to be affected together, either because of the disease process or in reflection of common cognitive ability. This enabled researchers to disentangle the brain map of cognitive abilities from the patterns of damage—allowing them to map the different parts of the brain and determine which patients did worse in the fluid intelligence task according to their injuries.

The researchers found that fluid intelligence impaired performance was largely confined to patients with right frontal lesions—rather than a wide set of regions distributed across the brain. Alongside brain tumours and stroke, such damage is often found in patients with a range of other neurological conditions, including traumatic brain injury and dementia.

These  findings indicate for the first time that the right frontal regions of the brain are critical to the high-level functions involved in fluid intelligence, such as problem solving and reasoning.

Lisa Cipolotti et al, Graph lesion-deficit mapping of fluid intelligence, Brain (2022). DOI: 10.1093/brain/awac304

Holding information in mind may mean storing it among synapses

Between the time you read the Wi-Fi password off the café's menu board and the time you can get back to your laptop to enter it, you have to hold it in mind. If you've ever wondered how your brain does that, you are asking a question about working memory that has researchers have strived for decades to explain. Now  neuroscientists have published a key new insight to explain how it works.

In a study in PLOS Computational Biology, scientists compared measurements of brain cell activity in an animal performing a working memory task with the output of various computer models representing two theories of the underlying mechanism for holding information in mind. The results strongly favoured the newer notion that a network of neurons stores the information by making short-lived changes in the pattern of their connections, or synapses, and contradicted the traditional alternative that memory is maintained by neurons remaining persistently active (like an idling engine).

While both models allowed for information to be held in mind, only the versions that allowed for synapses to transiently change connections ("short-term synaptic plasticity") produced neural activity patterns that mimicked what was actually observed in real brains at work. The idea that brain cells maintain memories by being always "on" may be simpler, but it doesn't represent what nature is doing and can't produce the sophisticated flexibility of thought that can arise from intermittent neural activity backed up by short-term synaptic plasticity.

You need these kinds of mechanisms to give working memory activity the freedom it needs to be flexible. If working memory was just sustained activity alone, it would be as simple as a light switch. But working memory is as complex and dynamic as our thoughts.

Using artificial neural networks with short-term synaptic plasticity, scientists show that synaptic activity (instead of neural activity) can be a substrate for working memory. The important takeaway from this paper is: these 'plastic' neural network models are more brain-like, in a quantitative sense, and also have additional functional benefits in terms of robustness.

Part 1

In addition to matching nature better, the synaptic plasticity models also conferred other benefits that likely matter to real brains. One was that the plasticity models retained information in their synaptic weightings even after as many as half of the artificial neurons were "ablated." The persistent activity models broke down after losing just 10–20 percent of their synapses. And just spiking occasionally requires less energy than spiking persistently.

Furthermore, quick bursts of spiking rather than persistent spiking leaves room in time for storing more than one item in memory. Research has shown that people can hold up to four different things in working memory. 

Leo Kozachkov et al, Robust and brain-like working memory through short-term synaptic plasticity, PLOS Computational Biology (2022). DOI: 10.1371/journal.pcbi.1010776

Part 2

South Asian black carbon causes glacier loss on Tibetan Plateau

Black carbon aerosol is the product of incomplete combustion of fossil fuels and biomass, and has strong light absorption. Black carbon deposition in snow ice reduces the albedo of the snow ice surface, accelerating the melting of glaciers and snow cover, and thus changing the hydrological process and water resources in the region.

The South Asia region adjacent to the Tibetan Plateau is one of the regions with high black carbon emission in the world. Black carbon aerosol from South Asia can transport across the Himalayan Mountains to the inland region of the Tibetan Plateau.

Recently, a  research team analyzed the influence of black carbon aerosols on regional precipitation and glaciers over the Qinghai-Tibet Plateau.

Their findings were published in Nature Communications on Nov. 30.

The researchers found that since the 21st century, the South Asian black carbon aerosols have indirectly affected the material supply of the Tibetan Plateau glaciers by changing water vapour transport in the South Asian monsoon.

Black carbon aerosols in South Asia heat up the middle and upper atmosphere, thus increasing the north-south temperature gradient.

Accordingly, the convective activity in South Asia is enhanced, which causes convergence of water vapor in South Asia. Meanwhile, black carbon also increases the number of cloud condensation nuclei in the atmosphere."

These changes in meteorological conditions caused by black carbon aerosols make more water vapor form precipitation in South Asia, and less water vapor transmit to the Tibetan Plateau. As a result, precipitation in the central and southern Tibetan Plateau decreases during monsoon, especially in the southern part of the Tibetan Plateau.

The decrease of precipitation further leads to the decrease of material supply of glaciers. From 2007 to 2016, the reduced material supply accounted for 11.0% of the average glacier material loss on the Tibetan Plateau and 22.1% in the southern part of the plateau.

"The transboundary transport and deposition of black carbon aerosols in South Asia accelerate glacier ablation on the Tibetan Plateau. Meanwhile, the reduction of plateau summer precipitation will reduce the material supply of plateau glacier, which will increase the amount of glacier material deficit.

Junhua Yang et al, South Asian black carbon is threatening the water sustainability of the Asian Water Tower, Nature Communications (2022). DOI: 10.1038/s41467-022-35128-1

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Gastroesophageal reflux disease raises risk for periodontitis: Study

Patients with gastroesophageal reflux disease (GERD) have an increased risk for periodontitis development, according to a study published online Nov. 19 in Biomedicines.

Researchers conducted a retrospective cohort study to examine the association between GERD and subsequent periodontitis risk using epidemiological data from the Taiwan National Health Insurance Research Database from 2008 to 2018. A total of 20,125 participants with a minimum age of 40 years were included in the GERD group and propensity-matched in a 1:1 ratio with non-GERD participants.

The researchers found that the incidence rate of periodontitis was significantly higher in patients with versus those without GERD (30.0 versus 21.7 per 1,000 person-years; adjusted hazard ratio, 1.36). Patients with GERD had a higher risk for periodontitis in analyses stratified for age (adjusted hazard ratios, 1.31 and 1.42 for age 40 to 54 and 55 to 69 years, respectively), sex (adjusted hazard ratios, 1.40 and 1.33 for men and women, respectively), and presence and absence of comorbidity (adjusted hazard ratios, 1.36 and 1.40, respectively) compared with those without GERD. The risk for periodontitis was increased with an increasing number of emergency room visits among the GERD cohort (one or more versus less than one; adjusted hazard ratio, 5.19).

"Clinicians should pay more attention to the development of periodontitis while caring for patients with GERD," the authors write. "On the other hand, dentists may consider GERD as an etiology of unexplained periodontitis."

Parental astigmatism may increase risk for child astigmatism

Parental astigmatism may confer an independent and dose-dependent association with child astigmatism, according to a study published online Dec. 21 in JAMA Network Open.

Researchers examined the association between parental astigmatism (an optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances) and child astigmatism. The analysis included 5,708 familial trios, each comprising a child aged 6 to 8 years and both parents, participating in the Hong Kong Children Eye Study.

The researchers found that astigmatism of ≥1.0 D in both parents was associated with greater odds of refractive astigmatism (RA; odds ratio, 1.62) and corneal astigmatism (CA; odds ratio, 1.94) in the child. When both parents had astigmatism ≥2.0 D, the risk increased further (odds ratios, 3.10 and 4.31, respectively), with higher parental astigmatism conferring higher risks for both RA and CA in children. There was a significant association between each parental astigmatism and corresponding child astigmatism (odds ratios, 0.76, 0.82, 1.70, and 1.33 for maternal RA, paternal RA, maternal CA, and paternal CA, respectively).

"The findings of this cross-sectional study suggest that parental astigmatism may confer an independent and dose-dependent association with child astigmatism," the authors write. "Children with parents with astigmatism should have early eye examinations for timely detection of astigmatism to facilitate age-appropriate vision correction and visual development."

Researchers discover that soap film on bubbles is cooler than the air around it

A team of researchers has discovered that the film that makes up ordinary soap bubbles is cooler than the surrounding air.

Bubbles exist in a wide variety of environments, from beer glasses to clothes and dish washers to crests on waves. They even exist in tiny environments, like in the space between human teeth. A lot of research has been done with bubbles, much of it focused on controlling them during industrial processes.

 In their work, the researchers created bubbles using ordinary dish soap, water and glycerol. After discovering a temperature difference, the team refocused their efforts to learn more. They tried changing the temperature of the air, the humidity level and also the proportions of the ingredients used to make the bubbles. They found that they were able to make bubbles that were up to 8 degrees Celsius cooler than the air around them. They also found that changing the amount of glycerol impacted the temperature of the resulting bubbles—more of it yielded higher temperatures.

The researchers suggest the cooler films could be the result of evaporation as the bubbles form. They noted also that as the bubbles persisted, their films slowly grew warmer, eventually matching the ambient air temperature. They suggest the large temperature differences they found with some bubbles might have an impact on bubble stability, and conclude that more work is required to find out why the films are cooler and if it might be a useful attribute.

 François Boulogne et al, Measurement of the Temperature Decrease in Evaporating Soap Films, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.129.268001. On Arxiv: arxiv.org/abs/2212.07104

Ketamine found to increase brain noise

An international team of researchers found that ketamine, being an NMDA receptor inhibitor, increases the brain's background noise, causing higher entropy of incoming sensory signals and disrupting their transmission between the thalamus and the cortex. This finding may contribute to a better understanding of the causes of psychosis in schizophrenia. An article with the study's findings has been published in the European Journal of Neuroscience.

Schizophrenic spectrum disorders affect approximately one in 300 people worldwide. The most common manifestations of these disorders are perceptual disturbances such as hallucinations, delusions and psychoses. A drug called ketamine can induce a mental state similar to psychosis in healthy individuals. Ketamine inhibits NMDA receptors involved in the transmission of excitatory signals in the brain. An imbalance of excitation and inhibition in the central nervous system can affect the accuracy of sensory perception. Similar changes in the functioning of NMDA receptors are currently thought to be one of the causes of perception disorders in schizophrenia. However, it is still unclear how exactly this process occurs in the brain regions involved.

To find out, neuroscientists 

studied how the brains of laboratory rats on ketamine process sensory signals. The researchers examined beta and gamma oscillations occurring in response to sensory stimuli in the rodent brain's thalamo-cortical system , a neural network connecting the cerebral cortex with the thalamus responsible for the transmission of sensory information from the organs of perception to the brain.

Beta oscillations are brainwaves in the range of 15 to 30 Hz, and gamma waves are those in the range of 30 to 80 Hz. These frequencies are believed to be critical for encoding and integrating sensory information.

In the experiment, rats were implanted with microelectrodes to record the electrical activity in the thalamus and the somatosensory cortex , a region of the brain which is responsible for processing sensory information coming from the thalamus. The researchers stimulated the rats' whiskers (vibrissae) and recorded the brain's responses before and after ketamine administration.

A comparison of the two datasets revealed that ketamine increased the power of beta and gamma oscillations in the cortex and the thalamus even in the resting state before a stimulus was presented, while the amplitude of the beta/gamma oscillations in the 200–700 ms post-stimulus period was significantly lower at all recorded cortical and thalamic sites following ketamine administration.

The post-stimulation time lapse of 200–700 ms is long enough to encode, integrate and perceive the incoming sensory signal. The observed decrease in the power of sensory stimulus-induced oscillations can be associated with impaired perception.

Part 1

Analysis also revealed that by inhibiting NMDA receptors, ketamine administration added noise to gamma frequencies in the post-stimulation 200–700 ms period in one thalamic nucleus and in one layer of the somatosensory cortex. It can be assumed that this observed increase in noise, ie a reduction in the signal-to-noise ratio, also indicates the neurons' impaired ability to process incoming sensory signals.

These findings suggest that psychosis may be triggered by an increase in background noise impairing the function of thalamo-cortical neurons. This, in turn, could be caused by a malfunction of NMDA receptors affecting the balance of inhibition and excitation in the brain. The noise makes sensory signals less defined or pronounced. In addition, this may cause spontaneous outbursts of activity associated with a distorted perception of reality.

"The discovered alterations in thalamic and cortical electrical activity associated with ketamine-induced sensory information processing disorders could serve as biomarkers for testing antipsychotic drugs or predicting the course of disease in patients with psychotic spectrum disorders.

 Yi Qin et al, The psychotomimetic ketamine disrupts the transfer of late sensory information in the corticothalamic network, European Journal of Neuroscience (2022). DOI: 10.1111/ejn.15845

Thomas J. Reilly, Ketamine: Linking NMDA receptor hypofunction, gamma oscillations and psychosis (commentary on Qin et al., 2022), European Journal of Neuroscience (2022). DOI: 10.1111/ejn.15872

Part 2 

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How chronic blood cancer transitions to aggressive disease

A type of chronic leukemia can simmer for many years. Some patients may need treatment to manage this type of blood cancer—called myeloproliferative neoplasms (MPN)—while others may go through long periods of watchful waiting. But for a small percentage of patients, the slower paced disease can transform into an aggressive cancer, called secondary acute myeloid leukemia, that has few effective treatment options. Little has been known about how this transformation takes place.

But now, researchers  have identified an important transition point in the shift from chronic to aggressive leukemia. They have shown that blocking a key molecule in the transition pathway prevents this dangerous disease progression in mice with models of the disease and in mice with tumors sampled from human patients.

Tim Kong et al, DUSP6 mediates resistance to JAK2 inhibition and drives leukemic progression, Nature Cancer (2022). DOI: 10.1038/s43018-022-00486-8

Quasicrystal formed during accidental electrical discharge

Quasicrystals, as their name suggests, are crystal-like substances. They possess characteristics not found in ordinary crystals, such as a non-repeating arrangement of atoms. To date, quasicrystals have been found embedded in meteorites and in the debris from nuclear blasts. In this new effort, the researchers found one embedded in a sand dune in Sand Hills, Nebraska.

A team of researchers  has found an incidence of a quasicrystal formed during an accidental electrical discharge.

Study of the quasicrystal showed it had 12-fold, or dodecagonal, symmetry—something rarely seen in quasicrystals. Curious as to how it might have formed and how it ended up in the sand dune, the researchers did some investigating. They discovered that a power line had fallen on the dune, likely the result of a lightning strike. They suggest the electrical surge from either the power line or the lightning could have produced the quasicrystal.

The researchers note that the quasicrystal was found inside of a tubular piece of fulgurite, which they suggest was also formed during the electrical surge due to fusing of melted sand and metal from the power line. 

In looking at the quasicrystal using an electron microscope, the researchers were able to make out its composition. In so doing, they found bits of silicon dioxide glass, which told them that temperatures inside the sand dune during the electrical discharge had to have reached at least 1,710 degrees Celsius. They also found that the quasicrystal had been retrieved from an area of transition between melted aluminum alloy and silicate glass. Their work confirmed that the object they were studying was, indeed, a quasicrystal, and that it had a previously unseen composition.

The researchers conclude that finding a quasicrystal in such a place suggests that others are likely out there, as well, having formed due to lightning strikes or downed power lines. They also suggest their work could lead to techniques to create quasicrystals in the lab.

Luca Bindi et al, Electrical discharge triggers quasicrystal formation in an eolian dune, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2215484119

Human brain organoids implanted into mouse cortex respond to visual stimuli for first time

 A team of engineers and neuroscientists has demonstrated for the first time that human brain organoids implanted in mice have established functional connectivity to the animals' cortex and responded to external sensory stimuli. The implanted organoids reacted to visual stimuli in the same way as surrounding tissues, an observation that researchers were able to make in real time over several months thanks to an innovative experimental setup that combines transparent graphene microelectrode arrays and two-photon imaging.

Madison N. Wilson, Martin Thunemann, Xin Liu, Yichen Lu, Francesca Puppo, Jason W. Adams, Jeong-Hoon Kim, Mehrdad Ramezani, Donald P. Pizzo, Srdjan Djurovic, Ole A. Andreassen, Abed AlFatah Mansour, Fred H. Gage, Alysson R. Muotri, Anna Devor, Duygu Kuzum. Multimodal monitoring of human cortical organoids implanted in mice reveal functional connection with visual cortex. Nature Communications, 2022; 13 (1) DOI: 10.1038/s41467-022-35536-3

Researchers identify 100,000 new types of viruses

A groundbreaking  study has discovered about 100,000 new types of previously unknown viruses , a ninefold increase in the amount of RNA viruses known to science until now. The viruses were discovered in global environmental data from soil samples, oceans, lakes, and a variety of other ecosystems. The researchers believe that the discovery may help in the development of anti-microbial drugs and in protecting against agriculturally harmful fungi and parasites. 

Self-assembling proteins can store cellular 'memories'

As cells perform their everyday functions, they turn on a variety of genes and cellular pathways. Researchers have now coaxed cells to inscribe the history of these events in a long protein chain that can be imaged using a light microscope.

Cells programmed to produce these chains continuously add building blocks that encode particular cellular events. Later, the ordered protein chains can be labeled with fluorescent molecules and read under a microscope, allowing researchers to reconstruct the timing of the events.

This technique could help shed light on the steps that underlie processes such as memory formation, response to drug treatment, and gene expression.

If the technique could be extended to work over longer time periods, it could also be used to study processes such as aging and disease progression, the researchers say.

Recording of cellular physiological histories along optically readable self-assembling protein chains, Nature Biotechnology (2022). DOI: 10.1038/s41587-022-01586-7

Dry eye disease affects how the eye's cornea heals itself after injury

People with a condition known as dry eye disease are more likely than those with healthy eyes to suffer injuries to their corneas. Studying mice, researchers at Washington University School of Medicine in St. Louis have found that proteins made by stem cells that regenerate the cornea may be new targets for treating and preventing such injuries.

Dry eye disease occurs when the eye can't provide adequate lubrication with natural tears. People with the common disorder use various types of drops to replace missing natural tears and keep the eyes lubricated, but when eyes are dry, the cornea is more susceptible to injury.

We have drugs to treat this condition, but they only work well in about 10% to 15% of patients. In this new study involving genes that are key to eye health, researchers identified potential targets for treatment that appear different in dry eyes than in healthy eyes. 

The researchers analyzed genes expressed by the cornea in several mouse models—not only of dry eye disease, but also of diabetes and other conditions. They found that in mice with dry eye disease, the cornea activated expression of the gene SPARC. They also found that higher levels of SPARC protein were associated with better healing.

Lin, Joseph B. et al, Dry eye disease in mice activates adaptive corneal epithelial regeneration distinct from constitutive renewal in homeostasis, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2204134120. doi.org/10.1073/pnas.2204134120

COVID-19 vaccines, prior infection reduce transmission of omicron, finds study 

Vaccination and boosting, especially when recent, helped to limit the spread of COVID-19 in California prisons during the first omicron wave, according to an analysis by researchers.

 The study demonstrates the benefits of vaccination and boosting, even in settings where many people are still getting infected, in reducing transmission. And it shows the cumulative effects from boosting and the additional protection that vaccination gives to those who were previously infected. The likelihood of transmission fell by 11% for each additional dose.

A lot of the benefits of vaccines to reduce infectiousness were from people who had received boosters and people who had been recently vaccinated.

Vaccinated residents with breakthrough infections were significantly less likely to transmit them: 28% versus 36% for those who were unvaccinated. But the likelihood of transmission grew by 6% for every five weeks that passed since someone's last vaccine shot.

Natural immunity from a prior infection also had a protective effect, and the risk of transmitting the virus was 23% for someone with a reinfection compared to 33% for someone who had never been infected.

Those with hybrid immunity, from both infection and vaccination, were 40% less likely to transmit the virus. Half of that protection came from the immunity that one acquires from fighting an infection and the other half came from being vaccinated.

 Infectiousness of SARS-CoV-2 breakthrough infections and reinfections during the Omicron wave, Nature Medicine (2022). DOI: 10.1038/s41591-022-02138-x , www.nature.com/articles/s41591-022-02138-x