Tech

Just as people tend to become stuck in their ways as they grow older so too do cells. Neurons in the brain don't one day decide to become heart cells; skin cells repair wounds with skin cells rather than kidney cells.

Cancer cells, on the other hand, are like perpetual teenagers. They're constantly trying on different identities and roles, which is partly what makes them so hard to control.

In research published February 10 in Nature Medicine, a team of scientists at Memorial Sloan Kettering Cancer Center and Weill Cornell Medicine reports that this developmental shape-shifting is key to cancer's ability to spread (metastasize) and interact with the body's immune defenses.

"We've known for a while that cancer cells tend to become more developmentally primitive, or stem cell-like, as they grow," says Ashley Laughney, a cancer biologist and the study's first author, who conducted the work as a postdoctoral fellow at the Sloan Kettering Institute and is now an assistant professor of physiology and biophysics at Weill Cornell Medicine. "What we were able to do in this study is identify the specific cell types that form primary tumors and compare them to those that make up distant metastases."

Focusing on lung cancer, the team discovered that the cell types in primary tumors and metastases fall along a spectrum of cells that regenerate injured tissue. The cell types in cancer that has spread are even more primitive than those in a primary tumor.

The findings bring a deeper understanding of cancer metastasis, says Joan Massagué, Director of the Sloan Kettering Institute and a co-corresponding author on the paper.

"These results focus our attention on the key role of regenerative cell types in recreating tumors in new locations," he says. "More and more, we are understanding that cancer cells co-opt normal developmental and wound-healing pathways to further their own ends."

It's a devious strategy but one that opens avenues for potential treatment, he explains.

The study was a collaborative effort and benefited from the expertise of SKI Computational and Systems Biology Program Chair Dana Pe'er, the paper's other co-corresponding author, and MSK physician-scientist Charles Rudin.

A Spectrum of Primitive States

In January 2020, the Massagué lab showed that markers of wound healing can be used to follow cancer cells as they detach from a primary tumor and spread to another location. The lab also found that isolated tumor cells are able to go undetected in the body by taking on certain properties of stem cells.

In this new study, the team used human tissue samples and mouse models to characterize the identities and behavior of tumor cells at each step of the journey -- from the primary tumor through the breaking off of individual tumor cells to full-blown metastases. They discovered a range of cell types along this path that mirrored those involved in lung development.

The scientists identified these cell types by combining two techniques. The first is called single-cell RNA sequencing (scRNA-seq). It allows investigators to measure which genes are turned on in thousands of individual cells at the same time. The team performed scRNA-seq on more than 40,000 individual cells from 17 samples obtained from people with lung cancer being treated at MSK. They then used advanced computational methods to interpret this head-spinning amount of data. Dr. Pe'er brought her team's computational expertise to the challenge.

The result was a map of the full range of cell types present in normal tissue, primary lung cancers, and lung cancer metastases. From this analysis it was clear that the pattern of cell types in primary tumors was recognizably different than that of cell types in metastatic tumors.

Within primary lung tumors, they found cell types involved in repairing the lung after injury -- of the sort that occurs, for example, whenever a person inhales soot or tobacco. However, these tumor cells were prone to identity confusion. They displayed markers of several identities at once.

Within metastatic lung tumors, the majority of cells had traveled even further back in time to resemble the stem cells that first give rise to the lungs during embryonic development. The team believes that this low degree of differentiation helps metastatic cells reinitiate growth in a new location.

"We observed the metastatic cell co-opting the earliest embryonic programs and mimicking organ formation," Dr. Pe'er says. "Thus, metastasis can be viewed as a dysfunctional organ that grows in the wrong place."

Underlying the ability of cancer cells to access such programs, which are locked to adult cells, she explains, is plasticity. "We are beginning to understand that plasticity is a key hallmark of cancer," she says.

Out-SOX'ing the Immune System

Two key developmental cues are involved in generating all of the cell types that make up the lung: the proteins SOX2 and SOX9. Through the scRNA-seq analysis, the researchers discovered that tumor cells attempting to reinitiate growth at a distant site turn on SOX2. This programs the cells to behave like embryonic stem cells. The tumor cells become skewed toward generating the type of cells that form lung tissue during embryonic development. Full-blown metastases, on the other hand, are mostly made up of cells that produce SOX9. They are more committed to regenerating specialized lung cell types.

To explore how the immune system responds to both of these primitive cells types, the scientists used a previously developed mouse model of metastasis-prone lung cancer. It turns out that the differentiation status of the tumor cells is the difference between life and death for these cells. The more stem cell-like, metastasis-initiating cells that turn on SOX2 behave in a way that makes them more conspicuous to the immune cells called natural killer (NK) cells. NK cells readily detect these SOX2-activated cells as they try to divide and destroy them. The cells that turn on SOX9, by contrast, go undetected by NK cells. For that reason, the bulk of metastases have few SOX2 cells while becoming enriched in SOX9 cells.

"SOX2 cells must become SOX9 fast or they will die at the hands of NK cells," Dr. Massagué explains.

"It is the cancer cell's plasticity that allows it to make such a switch to survive," adds Dr. Pe'er.

The investigators argue that these findings ought to encourage cancer biologists to think differently about how best to treat metastatic cancer. For example, a treatment that kills cells making up the bulk of a metastatic tumor might not stop cells that give rise to metastasis in the first place.

"In many ways, it is these metastasis-initiating cells that we would like to be able to specifically target," says Dr. Laughney, who is also an assistant professor of computational cancer genomics in computational biomedicine in the HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine at Weill Cornell Medicine. "But getting rid of these lethal and solitary metastasis-initiating cells will likely require different strategies than the ones doctors use to treat a primary tumor or even a full-blown metastasis."

The team is now working to develop such therapies.

Women aged 50-70 are more likely than younger women to consume alcohol at levels that exceed low risk drinking guidelines - and most think that's just perfectly fine.

New Edith Cowan University (ECU) research has found that despite the potential health risks of exceeding national drinking guidelines, many middle-aged and young-old women who consume alcohol at high risk levels tend to perceive their drinking as normal and acceptable, so long as they appear respectable and in control.

The study is a collaboration between ECU and Aalborg University, Denmark, led by Dr Julie Dare from ECU's School of Medical and Health Sciences. It investigated the social construction of alcohol use among 49 women aged 50 to 69 in Denmark and Australia.

According to Australian health authorities, drinking more than two standard drinks on any day increases the risk considerably of premature death over a woman's lifetime.

Key findings:

Women place more importance on appearing to be in control, behaving respectably, social pleasure and feeling liberated than the quantity of alcohol consumed or potential health risks.

While some women reported reducing their drinking due to health concerns, others suggested that positive health behaviours such as exercise served to 'neutralise' alcohol-related health risks.

Health advice and interventions relating to middle-aged and young-old women's drinking practices need to acknowledge that women may socially construct their drinking practices to prioritise matters other than biomedical impacts of alcohol.

Controlled and acceptable drinking

Dr Dare said the research highlighted the widespread use of alcohol in both samples of women in Australia and Denmark.

"Respondents from both countries indicated that alcohol use among women their age was normal and acceptable," she said.

One respondent observed:

"It has become part of the norm . . . it is something we do with our acquaintances, friends and families. That's just something we do" (D8, 59 years).

"However, the importance of 'staying in control' while drinking emerged as an important qualifier to the social acceptability of drinking," Dr Dare said.

Another respondent said:

"As long as they (women) don't make a fool of themselves, they don't want to go falling down and showing their knickers" (A9, 69 years).

"Health messaging of no more than two standard drinks per day and no more than four standard drinks on any single drinking occasion didn't seem to be relevant to women in this age group. There was a fair percentage drinking over that," Dr Dare said.

"In Australia, younger women are starting to drink less, their rates have declined, but the proportion of women aged 60 and older drinking at levels that exceed single occasion guidelines (more than 4 standard drinks on a single occasion) has increased. Similar trends are evident in Denmark and the United Kingdom."

Cultural differences

While the study highlighted many similarities between Australian and Danish women, one interesting cultural difference was the way Australian women thought about alcohol in relation to stress.

"If the Australian women had some sort of distress in their lives they believed it was acceptable to drink. They were quite open about this saying 'I just had a bad day, I needed to have a drink'," Dr Dare said.

"Danish women were not the same. They reported it wasn't 'acceptable' to drink if they were upset. They believed that you shouldn't use alcohol as a crutch to cope," she said.

When NASA's Aqua satellite passed over the Southern Indian Ocean on Feb. 7, it gathered water vapor data that provided information about the intensity of Tropical Cyclone Damien.

On Feb. 7 at 12:25 a.m. EST (1725 UTC), NASA's Aqua satellite passed over Tropical Cyclone Damien, located in the Southern Indian Ocean and off Australia's Pilbara coast. Aqua found highest concentrations of water vapor (brown) and coldest cloud top temperatures were around the center. Credits: NASA/NRLThe Australian Bureau of Meteorology (ABM) issued warnings and watches as Tropical Cyclone Damien moves toward the Pilbara Coast of Western Australia.

On Friday, February 7 at 11:46 pm WST (10:46 a.m. EST), the Warning Zone extends from Pardoo to Onslow, including Port Hedland, Karratha, Dampier, Pannawonica and Barrow Island and extending to adjacent inland parts to include Marble Bar, Tom Price and Paraburdoo. The Watch Zone includes inland central Pilbara including Nullagine, Newman and Mt Augustus.

ABM forecasters expect Severe Tropical Cyclone Damien to cause gales on the Pilbara coast from early Saturday morning. Very Destructive winds, very heavy rainfall and a storm surge are expected as Damien crosses the coast during Saturday, Feb. 8.

NASA's Aqua satellite passed over Tropical Cyclone Damien on Feb. 7 at 12:25 a.m. EST (1725 UTC) and the Moderate Resolution Imaging Spectroradiometer or MODIS instrument gathered water vapor content and temperature information. The MODIS image showed highest concentrations of water vapor and coldest cloud top temperatures were around the center of circulation.

MODIS data also showed coldest cloud top temperatures were as cold as or colder than minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius) in those storms. Storms with cloud top temperatures that cold have the capability to produce heavy rainfall.

Water vapor analysis of tropical cyclones tells forecasters how much potential a storm has to develop. Water vapor releases latent heat as it condenses into liquid. That liquid becomes clouds and thunderstorms that make up a tropical cyclone. Temperature is important when trying to understand how strong storms can be. The higher the cloud tops, the colder and the stronger the storms.

On February 7 at 11:46 pm WST (10:46 a.m. EST), ABM reported that Damien was a Category 3 storm with maximum sustained winds near the center of 140 kilometers (87 miles) per hour with higher wind gusts. Damien was located near latitude 18.9 degrees south and longitude 16.7 degrees east, about 205 kilometers (127 miles) north of Karratha and 255 kilometers (158 miles) northwest of Port Hedland. Damien is moving to the south-southwest.

Forecasters at the ABM reported on Feb. 7, "Severe Tropical Cyclone Damien (Category 3) is expected to intensify as it moves towards the Pilbara coast. Damien is likely to cross the coast between Whim Creek and Mardie during Saturday as a Category 4 system. Later on Saturday or Sunday, Damien will move inland and weaken."

For the Australian Bureau of Meteorology Weather video update on Feb. 7, visit: https://youtu.be/TgO9v0mYiCM

NASA's Aqua satellite is one in a fleet of NASA satellites that provide data for hurricane research.

Tropical cyclones/hurricanes are the most powerful weather events on Earth. NASA's expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

An interdisciplinary team of researchers at Colorado State University has used computational chemistry, biochemistry and virology to uncover new information on how viruses such as West Nile, dengue and Zika replicate. Based on their research, the team said these viruses appear to cripple their own genome replication machinery.

CSU researchers described the results as "surprising," and said the findings have implications for future vaccine and antiviral drug development.

The study, "Motif V regulates energy transduction between the flavivirus NS3 ATPase and RNA-binding cleft," was published in the Journal of Biological Chemistry on Feb. 7.

How a virus replicates

Kelly Du Pont, first author of the study and a doctoral candidate in chemistry at CSU, studies Nonstructural Protein 3 - or NS3 - in flaviviruses, which cause a number of diseases in humans. NS3 is a key enzyme that these viruses use to copy their genomes.

For flaviviruses to replicate, the NS3 helicase - a viral enzyme that binds or remodels nucleic acid - has to unwind the double-stranded ribonucleic acid. NS3 uses adenosine triphosphate or ATP, a molecule abundant in cells, as fuel to power the unwinding.

Du Pont said the unwinding action is similar to what happens with a zipper on a jacket, while the energy produced from ATP driving the unwinding is similar to the transmission system of a car.

"The release of energy from the fuel drives the pistons up and down to turn the transmission and then the wheels, causing the car to move forward," she said. "NS3 uses ATP as its fuel to unwind the double-stranded ribonucleic acid, but we don't know where the crankshaft or transmission is for this machine."

Du Pont said this research was initially focused on trying to figure out what part of the NS3 protein acts as its molecular transmission. While studying the process, the team identified the part of NS3 that acts as a brake during unwinding.

They also identified mutations that make NS3 unwind the double-stranded ribonucleic acid faster than is normally seen, but also make the virus replicate more inefficiently in cells.

Potential for drug, vaccine development

If researchers can learn more about how NS3 unwinds the double-stranded ribonucleic acid and how this process is controlled, they could potentially target areas within the helicase for development of drugs to treat virus-caused diseases.

Brian Geiss, senior author on the study and associate professor of microbiology at CSU, said the findings could also one day lead to improved development of vaccines against these viruses.

"Most vaccines are developed by finding random mutations that slow down virus growth," he said. "By understanding how viral enzymes like NS3 work in great detail, we can use that information to rationally design new mutant viruses that replicate less well and act better as a vaccine, without having to rely on chance to make the vaccine. This can help develop vaccines more rapidly and precisely."

Du Pont, who specializes in creating computational simulations, has been working in Geiss's lab in the Department of Microbiology, Immunology and Pathology. While interdisciplinary work is common at CSU, Geiss said the breadth of Du Pont's project is not typical.

"Kelly represents a true interdisciplinary scientist who can use the tools and knowledge from many different areas of science to answer previously unanswerable questions," he said. "She uses computational chemistry, protein biochemistry and enzymology, and classical virology techniques to study how these viruses work in unprecedented detail. Kelly is what I hope we will see more of in terms of the scientist of the future," he said.

The research team is now taking a closer look at how changes in NS3 affect replication of the virus and how the changes affect the ability of the virus to kill cells. Du Pont and Geiss are also working with the Ebel Laboratory at CSU to see how viruses with altered NS3 proteins infect mosquitoes and alter their survival during infection.

ATLANTA--A new method to detect cancer in its early stages using a targeted MRI contrast agent that binds to proteins has been identified by a team of researchers led by Georgia State University Regents' Professor Jenny Yang.

In their study, published in the journal Science Advances, Yang and her colleagues at Georgia State and Emory University describe a newly identified biomarker for detection of liver metastases. With current tests like biopsies, cancer in the liver is often detected in advanced stages, which can limit treatment options and lower overall survival rates. The discovery could have wide-ranging impacts, including more effective diagnosis and precision treatment, and less risk to patients.

"This is a game changer. It has the possibility to have many more applications, really for any type of cancer," said Yang. "We are already applying it to 10 different types of cancer in the lab."

The researchers, whose work is funded by the National Cancer Institute, developed an agent that can target certain receptors -- in this case, chemokine receptor 4 (CXCR4). The receptor is overexpressed in common metastasis organs, such as the liver, among people who have cancer.

The CXCR4 targeted protein-based MRI contrast agent is expected to overcome major barriers in early diagnosis by showing even tiny instances of cancer cells on multi-color scans called precision MRI (pMRI), a new imaging methodology.

Using MRI technology, contrast agents carry the element gadolinium to enhance the images. During her previous work analyzing calcium, Yang decided to test how a metal, like gadolinium, would interact with protein. The protein wraps around the element and carries it to the site for imaging. Yang's team found that protein design is much more effective in targeting the signs of disease.

"Currently, it is difficult to see early stages of disease in the liver, even in invasive biopsy," said Yang. "Diagnostic testing using this contrast agent can not only identify the presence of disease but differentiate the stages of disease with high sensitivity and accuracy. That's the beauty of this work."

The findings are so promising, the targeted protein contrast agent is now being fast-tracked by the U.S. Food and Drug Administration (FDA) in the first step toward clinical trials to gauge its efficacy in humans.

"We have already met with the FDA, so we have a blueprint," said Yang. "We hope within 18 months to two years we can conduct our first clinical trials in patents."

Yang, who is also the associate director of the Center for Diagnostics and Therapeutics, holds 17 U.S. and 18 foreign patents in protein engineering. She recently became the university's first professor to be awarded a fellowship by the National Academy of Inventors. Her start-up company InLighta Biosciences has been a key channel to allow her to compete for important funding and bring new discoveries to the marketplace.

The research builds on a 2019 study published in the journal Nature Communications, in which Yang's team identified the first early detection of liver fibrosis using a collagen-targeted protein contrast agent. Combined, these studies represent the work of more than a dozen scientists from universities across the U.S., and their discoveries could help transform a $300 million industry that has seen few advances in the past several decades.

"We have been using the same contrast agents for 30 years with few breakthroughs," said Yang. "I think this is my biggest scientific contribution. And I hope there are many more to come."

A group of St. Petersburg scientists has proposed and experimentally tested a technology for the fabrication of high-efficiency solar cells based on A3B5 semiconductors integrated on a silicon substrate, which in the future may increase the efficiency of the existing single-junction photovoltaic converters by 1.5 times. The development of the technology was forecasted by the Nobel Laureate Zhores Alferov. The results have been published in the journal Solar Energy Materials and Solar Cells.

Today, with the rapid exhaustion of hydrocarbon fuel reserves and a growing concern about environmental issues, scientists are paying more and more attention to the development of the so-called "green technologies". One of the most popular topics in the field is the development of solar energy technologies.

However, wider use of the solar panels is hindered by a number of factors. Conventional silicon solar cells have a relatively low efficiency - less than 20%. More efficient technologies require much more complex semiconductor technologies, which significantly increases the price of the solar cells.

The St. Petersburg scientists have proposed a solution to this problem. The researchers from ITMO University, St. Petersburg Academic University and the Ioffe Institute showed that A3B5 structures could be grown on inexpensive silicon substrate, providing decrease in the price of multi-junction solar cells.

"Our work focuses on the development of efficient solar cells based on A3B5 materials integrated on silicon-substrate," comments Ivan Mukhin, an ITMO University researcher, head of a laboratory at Academic University and a co-author of the study. "The main difficulty in the epitaxial synthesis on silicon-substrate is that the deposited semiconductor must have the same crystal lattice parameter as silicon. Roughly speaking, the atoms of this material should be at the same distance from each other as are the silicon atoms. Unfortunately, there are few semiconductors that meet this requirement - one example is gallium phosphide (GaP). However, it's not very suitable for the fabrication of the solar cells since it has poor sunlight-absorbing property. But if we take GaP and add nitrogen (N), we obtain a solution of GaPN. Even at low N concentrations, this material demonstrates the direct-band property and is great at absorbing light, as well as having the capability to be integrated onto a silicon substrate. At the same time, silicon doesn't just serve as the building material for the photovoltaic layers - it itself can act as one of the photoactive layers of a solar cell, absorbing light in the infrared range. Zhores Alferov was one of the first to voice the idea of combining ASB5 structures and silicon."

Working at the laboratory, the scientists were able to obtain the top layer of the solar cell, integrated onto a silicon substrate. With increase of the photoactive layers number the efficiency of the solar cell grows, as each layer absorbs its part of the solar spectrum.

As of now, the researchers have developed the first small prototype of a solar cell based on the A3B5 on silicon-substrate . Now they are working on the development of the solar cell that would consist of several photoactive layers. Such solar cells will be significantly more effective at absorbing sunlight and generating electricity.

"We've learned to grow the topmost layer. This material system can potentially also be used for intermediate layers. If you add arsenic, you obtain quaternary GaPNAs alloy, and from it several junctions operating in different parts of the solar spectrum can be grown on a silicon substrate. As demonstrated in our previous work, the potential efficiency of such solar cells can exceed 40% under light concentration, which is 1.5 times higher than that of modern Si technologies," concludes Ivan Mukhin.

An international research team have for the first time observed dynamic covalent oligomers mimicking the combination of complementary DNA strands, which could lead to exciting developments in electronics and the engineering of interfaces between prostheses and body tissue.

The study by Associate Professor Timothy Scott (Department of Chemical Engineering and Department of Materials Science and Engineering at Monash University) and Samuel Leguizamon (Department of Chemical Engineering at the University of Michigan), reported that during the assembly process, oligomers were able to selectively bind with their complementary sequences by using covalent bond formation.

This effectively strengthened the thermal and mechanical stability of the resultant structures through the creation of a DNA-like molecular ladder.

Published on Friday 7 February 2020, in the prestigious journal Nature Communications, these findings could have benefits for the superior creation of nanostructures (solar capture technology), the assembly of molecular electronics (wires and transistors), and the engineering of interfaces between prostheses and human tissue.

Oligomers are low weight polymers - a chemical compound of molecules presented in chains - whose physical properties are significantly dependent on the length of the chain.

They are currently used to improve performance in a wide variety of coatings, such as adhesives, chemical resistance and for improved weathering.

Oligomers, due to their ability to reduce volatile organic compounds (harmful vapours emitted by products) and application viscosity (the thickness of which a product is applied), are commonly found in products, such as paint and varnish.

But, researchers believe this new finding could open the door for these oligomers to be applied in the health and technology sectors.

"The ability to direct the self-assembly of oligomeric strands based on their residue sequence and mediated by dynamic covalent interactions is a crucial step towards the fabrication of complex, unimolecular constructs from modest, synthetically accessible precursors," Associate Professor Scott said.

"Although this study involved molecular ladders bearing covalent rungs, this multi-step approach to dynamic covalent assembly process may also be useful for other application in which the alleviation or elimination of kinetic trapping is critical.

"This process will provide significantly improved synthetic access to robust, complex covalent nanostructures, such as molecular cages and crystalline, porous polymer networks."

Many greenhouses could become energy neutral by using see-through solar panels to harvest energy - primarily from the wavelengths of light that plants don't use for photosynthesis. Those are the findings of a new modeling study conducted by engineering, plant biology and physics researchers at North Carolina State University.

"Plants only use some wavelengths of light for photosynthesis, and the idea is to create greenhouses that make energy from that unused light while allowing most of the photosynthetic band of light to pass through," says Brendan O'Connor, corresponding author of the study and an associate professor of mechanical and aerospace engineering at NC State. "We're able to do this by using organic solar cells, because they allow us to tune the spectrum of light that the solar cell absorbs - so we can focus on using mostly wavelengths of light that plants don't use. However, until now it wasn't clear how much energy a greenhouse could capture if it was using these semitransparent, wavelength selective, organic solar cells."

To address that question, researchers used a computational model to estimate how much energy a greenhouse could produce if it had semitransparent organic solar cells on its roof - and whether that would be enough energy to offset the amount of energy the greenhouse required to operate effectively. The model was developed to estimate energy use for greenhouses growing tomatoes at locations in Arizona, North Carolina and Wisconsin.

"A lot of the energy use in greenhouses comes from heating and cooling, so our model focused on calculating the energy load needed to maintain the optimal temperature range for tomato growth," O'Connor says. "The model also calculated the amount of energy a greenhouse would produce at each location when solar cells were placed on its roof."

The modeling is complex because there's a complicated trade-off between the amount of power the solar cells generate and the amount of light in the photosynthetic band that they allow to pass through. Basically, if growers are willing to sacrifice larger amounts of photosynthetic growth, they can generate more power.

What's more, the solar cells used for this analysis are effective insulators, because they reflect infrared light. This helps to keep greenhouses cooler in the summer, while trapping more warmth in the winter.

The end result is that, for many greenhouse operators, the trade-off could be a small one. Particularly for greenhouses in warm or temperate climates.

For example, in Arizona, the greenhouses could become energy neutral - requiring no outside source of power - while blocking only 10% of the photosynthetic band of light. However, if growers are willing to block more photosynthetic light, they could generate twice as much energy as they required to operate the greenhouse. In North Carolina, a greenhouse could become energy neutral while blocking 20% of the photosynthetic light. In Wisconsin, greenhouses couldn't become energy neutral using the semitransparent solar cells - keeping the greenhouse warm in winter requires too much energy. However, the solar cells could meet up to 46% of the greenhouse's energy demand.

"While the technology does use some of the light plants rely on, we think the impact will be negligible on plant growth - and that the trade-off will make financial sense to growers," O'Connor says.

Scientists at the University of Groningen used a silver sawtooth nanoslit array to produce valley-coherent photoluminescence in two-dimensional tungsten disulfide flakes at room temperature. Until now, this could only be achieved at very low temperatures. Coherent light can be used to store or transfer information in quantum electronics. This plasmon-exciton hybrid device is promising for use in integrated nanophotonics (light-based electronics). The results were published in Nature Communications on 5 February.

Tungsten disulfide has interesting electronic properties and is available as a 2D material. 'The electronic structure of monolayer tungsten disulfide shows two sets of lowest energy points or valleys,' explains Associate Professor Justin Ye, head of the Device Physics of Complex Materials group at the University of Groningen. One possible application is in photonics, as it can emit light with valley-dependent circular polarization - a new degree of freedom to manipulate information. However, valleytronics requires coherent and polarized light. Unfortunately, previous work showed that photoluminescence polarization in tungsten disulfide is almost random at room temperature.

Valleys

'Tungsten disulfide is unique in that these two valleys are not identical,' says Ye. This means that to create linearly polarized light, both valleys must respond coherently to generate light in the photoluminescence. 'But the intervalley scattering at room temperature largely destroys the coherence, so appreciable coherence is only achieved at very low temperatures that are close to zero.'

Ye and his postdoctoral researcher Chunrui Han (now working at the Institute of Microelectronics, Chinese Academy of Sciences) therefore tried a different approach to create linearly polarized light by using a plasmonic metasurface, in the form of a silver sawtooth nanoslit array. Such a material interacts strongly with tungsten disulfide and can transfer resonance induced by light in the form of an electromagnetic field in the metal. 'It enhances the light-material interaction,' says Ye.

Silver

By adding a thin layer of silver metasurface on top of a monolayer of tungsten disulfide, linear polarization induced by the valley coherence is increased to around 27 percent at room temperature. 'This room temperature performance is even better than the valley polarization obtained in many previous reports measured at very low temperatures,' says Ye. The linear polarization could be further increased to 80 percent by adding the anisotropy of plasmonic resonance, in the form of the sawtooth pattern, to the optical response of the tungsten disulfide. This means that Ye and Han are now able to induce linearly polarized photoluminescence in this material.

This accomplishment will make it possible to use both valley coherence of tungsten disulfide and plasmonic coherence of metasurfaces in optoelectronics at ambient temperatures. The next step is to replace the laser light that induced photoluminescence with electrical input.

Supercharging the mutation rate in cancer cells can create a powerful vaccine that is able to boost the effectiveness of immunotherapy, a major new study reports.

Scientists forced cancer cells in the lab to evolve much more rapidly than usual using a molecule called APOBEC3B, which is often used by tumours to drive rapid genetic change and drug resistance.

They found that these highly mutated cancer cells could be used to create a vaccine for each individual cancer type, which amplified the effects of immunotherapy - and cured mice with a variety of otherwise treatment-resistant tumours.

The international study - carried out by scientists at The Institute of Cancer Research, London, the Mayo Clinic in Rochester, US, and the University of Leeds - is the first to show that APOBEC3B's role in driving cancer evolution can be used to create vaccines that can boost the immune response.

The researchers want to take their new technique for creating personalised vaccines into the clinic as early as next year - starting with a trial in children with brain tumours.

The findings are published in Nature Communications today (Friday).

The researchers first showed they could drive rapid genetic changes in human cancer cells in the lab using high levels of APOBEC3B, which is able to edit the DNA code of cells, giving rise to genetic changes that can be seen as 'signatures' or 'footprints'.

The genetic analysis revealed more than a million extra mutations in the cells expressing APOBEC3B, compared with control cells. Of these, around 68,000 contained the classical APOBEC signature. These genetic signatures made cancer cells vulnerable to treatment with immune checkpoint blockade, a major strategy in immunotherapy.

However, by generating new genetic changes, APOBEC3B can also drive cancer evolution and help cancer cells become resistant to chemotherapy. So rather than give APOBEC3B directly to tumours as a treatment, the researchers instead used the genetic signature it left behind to create individual cancer vaccines, each tailored to the particular genetic profile of a specific tumour.

They gave mice highly mutated cancer cell vaccines, in the form of mutant cancer proteins, and these elicited an immune attack against their tumours as they were immediately detected as 'foreign'.

By combining the individualised tumour vaccines with checkpoint inhibitor immunotherapy, the researchers were able to cure melanoma and brain tumours in mice.

The next step is further preclinical research to translate these findings further into human cell systems, with the aim to take the vaccine technique into clinical trials for paediatric brain tumors within the next year.

The Institute of Cancer Research (ICR) has been focusing on increasing its understanding of APOBEC protein molecules, which are crucial to the ability of the immune system to adapt to different infectious diseases - but are also hijacked in many cancers to speed up evolution of drug resistance.

The potential of APOBEC inhibitors to slow down cancer evolution is enormous. This study now demonstrates that APOBEC3B could also be used to increase the effectiveness of new treatments that use immunotherapy to attack tumours.

The ICR - a charity and research institute - is creating a new £75 million Centre for Cancer Drug Discovery to study molecules like APOBEC3B, with the aim of creating new cancer treatments that can overcome the major challenge of cancer evolution and drug resistance. The ICR has less than £10 million left to raise to deliver the new building.

This study was supported by a variety of funders - the National Institute of Health, the European Research Council, the Richard M. Schulze Family Foundation, the University of Minnesota and Mayo Clinic Partnership, Cancer Research UK, the Shannon O'Hara Foundation, Hyundai Hope On Wheels, and a research grant from Oncolytics Biotech.

Study author Alan Melcher, Professor of Translational Immunotherapy at The Institute of Cancer Research, London, said:

"Our new study rather paradoxically takes advantage of a mechanism used by cancers to rapidly evolve and become resistant to chemotherapy, and instead makes them much more vulnerable to the effects of immunotherapy.

"We have supercharged genetic changes in cancer in order to create cancer vaccines, which are tailored to the genetic code of these tumours, and can boost the immune response against them."

"By combining our vaccines with checkpoint inhibitor chemotherapy, we've shown in mice that it's possible to cure tumours in a variety of locations, including the brain. Our new approach has the potential to be effective against cancers that do not currently respond to treatment, and we're keen to take it into clinical trials as soon as possible."

Professor Paul Workman, Chief Executive of The Institute of Cancer Research, London, said:

"Cancer's ability to evolve and become drug resistant is the biggest challenge we face in treating the disease more effectively. But this exciting new study also suggests it is possible to use a key evolutionary mechanism against cancers, by forcing them to accumulate genetic mutations that are able to spark the immune system against them.

"This is a terrific example of the kind of exciting research into cancer evolution and drug resistance that will be the focus of our pioneering £75 million Centre for Cancer Drug Discovery, and which we hope will deliver entirely new types of cancer treatment."

Co-author Dr Adel Samson, from the University of Leeds' School of Medicine, said:

"Adult cancers are caused by an accumulation of genetic mutations, which can provide resistance to conventional chemotherapy drugs. However, the same mutations make it possible for the immune system to detect and kill the cancer.

"This study demonstrates how we might apply this concept to future therapeutic cancer vaccines, by artificially mutating patient-derived cancerous cells in the laboratory, then injecting the mutated cell proteins back into the same patient. In doing so, this immunotherapy would be able to trigger an immune response against both the artificially mutated proteins, as well as the closely related cancerous cells originally present in a patient."

The conversion and utilization of solar energy for chemical fuel production and environmental remediation through artificial photocatalysis have been recognized to be an ideal route to address the critical energy and environmental concerns. The full utilization of solar light is a great challenge for achieving sufficient efficiency in practical applications, and narrowing the bandgap of a photocatalyst weakens the driving force for redox reactions, especially water oxidation and pollutant degradation, because these reactions involve a complicated multi-electron process. Therefore, the development wide-spectrum responsive and highly efficient photocatalysts for water oxidation and pollutant degradation is a critical issue to be addressed at present.

Bi-based oxometallate materials, such as BiVO4¬, Bi2WO6, Bi2MoO6, etc., have been widely studied as visible-light active photocatalysts and exhibit excellent photocatalytic performance in water oxidation and pollutant degradation, which is mainly benefiting from their sufficiently deep valence band position. In this work, a wide-spectrum responsive Bi8(CrO4)O11 nanorod photocatalyst was successfully constructed. Owing to the hybridization of Cr 3d with O 2p orbitals shifts conduction band minimum down, Bi8(CrO4)O11 allows its absorption up to the entire visible region (~678 nm) with a theoretical solar spectrum efficiency of 42.0%. And its VB of 1.95 eV (vs. NHE pH=7) is more positive than the oxidation potential of OH-/O2, which indicates that the photogenerated holes of Bi8(CrO4)O11 nanorod photocatalyst possess extremely strong oxidation capability.

As shown in Figure 1a, Bi8(CrO4)O11 exhibited exceedingly superior photocatalytic water oxidation performance, and its average O2 evolution rate reached 14.94 μmol h-1, about 11.5 and 4.0 times higher than that of Bi2WO6 nanosheets and commercial WO3 nanoparticles. Besides, it consequently achieved a considerable apparent quantum efficiency (AQE) 2.87% at 420 nm, even 0.65% at 650 nm (Figure 1b), higher than many reported wide-spectrum driven photocatalysts. Most noticeably, its excellent activity is also manifested in photocatalytic degradation of phenol. Its degradation reaction constant could reach 0.119 min-1, about 22.5 and 8.8 times higher than CdS nanowires and PDI supramolecular photocatalysts, respectively (Figure 1c). Even its degradation activity is not inferior to P25 TiO2 under simulated sunlight, about 2.9 times higher than the latter. Remarkably, Bi8(CrO4)O11 also presented extremely strong mineralization ability, which almost enables the simultaneous degradation and complete mineralization for phenol. The total organic carbon removal rates of phenol over Bi8(CrO4)O11 under visible light and simulated sunlight is 94.8% (degradation rate: 95.5%) and 97.3% (degradation rate: 98.1%) in 0.5 h, respectively, while that of CdS, PDI and P25 are significantly lower than their corresponding degradation rates. Even under 650 nm red light irradiation, Bi8(CrO4)O11 is still able to simultaneously degrade and completely mineralize phenol (Figure 1d), and few wide-spectrum driven photocatalysts can achieve that.

Besides, the dipole moments of Bi8(CrO4)O11 was calculated to 22.32 Debye (D), which results in a giant internal electric field (IEF). As shown in Figure 1e, compared to Bi14CrO24, Bi8(CrO4)O11 with a greater dipole showed a significantly higher IEF, charge separation efficiency and photocatalytic performance. Therefore, as illustrated in Scheme 1, the large crystal dipole of Bi8(CrO4)O11 induces a giant IEF, which accelerates the rapid separation of photogenerated electron-hole pairs and exponentially enhances its photocatalytic performance. Most importantly, based on the above mechanism, many more efficient photocatalysts can be designed successfully by regulating the crystal dipole.

Children with ADHD from the poorest areas are significantly more likely to receive medication as children with ADHD from the most affluent areas, according to the first UK study of its kind.

Previous research has shown that children in poorer areas are more likely to be diagnosed with ADHD. This new research in BJPsych Open, published on behalf of the Royal College of Psychiatrists, is the first UK study to show an association between deprivation and the likelihood of receiving medication for ADHD.

The finding is unlikely to have a single, simple explanation, but suggests that children from poorer areas are less able to benefit from treatments which don't involve medication, such a behavioural management classes for parents. Parents in poorer areas may find it more difficult to attend these regular classes, because of economic insecurity, for example working multiple jobs.

Dr Samuel Nunn, junior doctor at Leeds Teaching Hospitals NHS Trust and lead author of the paper, said: "This finding is important because it has implications for those in clinical practice and for policymakers. Further research would inform development of possible interventions to tackle the effects of social deprivation, though progress may be difficult unless the broader social determinants of health are addressed."

Researchers investigated a sample of 1,354 young people with a diagnosis of ADHD in the Sheffield area. Household postcodes were used to derive a standard measure of socioeconomic deprivation.

Statistical analysis showed that higher deprivation was associated with a higher likelihood of receiving medication, after controlling for age, sex, religion, ethnicity and the presence of other diagnoses.

Digital media have fundamentally changed the way we consume news. It is often assumed that the use of social networks and search engines has had a negative impact on the diversity of news that people access. This is often attributed to the algorithmic filtering used by these intermediaries, which only displays information that corresponds to the individual users' interests and preferences. However, a recent study undertaken by researchers from Johannes Gutenberg University Mainz (JGU), the University of Hohenheim, and GESIS - the Leibniz Institute for the Social Sciences in Cologne contradicts this widespread conjecture. Based on an innovative analysis of the web browsing behavior of more than 5,000 German Internet users, the results show that the use of intermediaries such as Facebook, Twitter, Google, or portals like GMX actually results in more visits to news sites and a greater variety of news sites visited. This runs counter to what has been postulated to date.

"Anyone visiting Facebook or Google is much more likely to come into contact with news items. Therefore the use of these intermediaries is an important mechanism in the consumption of news on the Internet," said Dr. Frank Mangold of the University of Hohenheim. The research team attributes this to the concept of incidental exposure to news. In the case of traditional media such as television and newspapers, people often only see the news if they deliberately choose to do so. On intermediary platforms they can also come into contact with news by chance, if, for example, their contacts share news content with them or they happen upon interesting articles when checking their emails. According to the researchers, the study's findings could have significant political and social implications, as they disprove the notion of the formation of filter bubbles and echo chambers. "Previous debates have, in many respects, revolved around the fear that online media would lead to new social barriers," said Professor Michael Scharkow of Mainz University. "However, our findings show that social media and search engines in fact have great potential to break down existing barriers."

"From previous studies undertaken by the University of Oxford in particular, we know that although access to news often happens partly by chance, it is also partly down to conscious choice. Some users even visit sites like Facebook and Twitter in order to consume news content," added Dr. Johannes Breuer of GESIS. For their study, the researchers used a statistical model to calculate the estimated daily usage of news content in order to isolate the extent of incidental or unplanned contact with news items. "Regardless of whether a user usually consumed a little or a lot of online news, on days on which someone spent more time on Facebook, Twitter, or Google than usual, they also came into contact with more news as well as more news from different sources than usual," stated Dr. Sebastian Stier from GESIS in the light of the findings.

Last but not least, the researchers also point out that further studies and more detailed insights into the algorithms of intermediaries are necessary in order to understand more precisely how these intermediaries promote unintended, incidental news consumption.

Mayflies have long been indicators of the ecological health of the lakes, rivers, and streams. The more mayflies present in water, the better the water quality. 

But scientists from Virginia Tech and the University of Notre Dame recently discovered that a particular species -- the burrowing mayfly -- had a population decrease of nearly 84 percent from 2015 to 2019. The measurements, using radar, took place during the annual insect emergence events at Lake Erie, when the transition of almost 88 billion insects moving from the waterways to the air marks one of world's largest annual insect emergence events.

Although it was previously impossible to analyze the emergence of the burrowing mayfly, researchers were finally able to do so by using meteorological radar data and new methods in tracking the presence of airborne creatures. By observing the swarms on a year-to-year basis, the data showed a shockingly simple trend: over the same timeframe and time of year, the mayfly swarms are growing smaller. 

"This refined radar technology that allows for tracking and quantifying aquatic insect populations at such a large scale is instrumental in understanding land-water connections," explained Sally Entrekin, an associate professor in the Department of Entomology in the Virginia Tech College of Agriculture and Life Sciences.

The finding speaks to more than just the mayfly's decline: It highlights the growing problem of insect decline and the cascading effects that has on ecosystems around the world.

"Radar technology -- coupled with traditional field sampling -- can start to address the scope and magnitude of insect declines from global change in aquatic ecosystems," said Entrekin.

Entrekin and her colleagues, Phil Stepanian, Charlotte Wainwright, Djordje Mirkovic, Jennifer Tank, and Jeffrey Kelly, recently published their findings in the Proceedings in the National Academy of Sciences.

The emergence is visually spectacular (where the skies are darkened by the shear mass of flying insects), but this event also represents a new availability of food for many creatures throughout the food chain, providing more than 3,000 tons of insects for consumption by birds and other land-based plants and animals.

Fish, birds, bats, and other animals consume the mayflies as a source of food and nutrients. Some insect-eating birds in these areas have synchronized breeding habits that coincide with mayfly emergence, and they rely on them as a high-quality food source for their young. These bird populations have also taken a downturn, which has been partially attributed to the lack of insects to eat, particularly aquatic insects.

Historically, negative human impacts on mayfly habitat has led to reductions and disappearances of the mayfly swarms. While conservation and habitat rehabilitation have helped to clean up the waterways and bring back the mayflies, in the Mississippi, Ohio, and Illinois rivers, as well as Lake Erie, efforts to bring back the mayfly swarms took nearly 20 years to reach their previous levels. As the research shows, it appears the swarms are once again declining.

Multiple stressors in these waterways attributed to human activity could be a reason for the reduction in mayfly populations. A warming climate puts more stress on certain aquatic environments, leading to decreased oxygen levels, which can result in fewer mayflies coming out of the water. Runoff from rivers into the warmer surface waters of Lake Erie, for instance, can cause algae blooms, which release toxins that these mayflies are especially susceptible to.

Another type of runoff from agricultural land carries commonly applied pesticides, particularly neonicotinoids, which can kill mayflies as immatures in the water. Even when these pesticides are present in nondeadly levels, they can negatively affect mayfly young by stunting their ability to reach adult stage. Many of these factors likely contribute to the decreasing mayfly populations, and policy and conservation efforts will be needed in order to change this trend.

Global insect population decline is an emerging topic that has sparked public awareness, however there are logistical challenges to analyzing these trends. Monitoring the life-cycle of the burrowing mayfly and other aquatic insects offers an early warning system for changes in our ecosystems.

This monitoring system is also applicable in other parts of the world where large aquatic emergence events occur, and it can be useful in pinpointing regions that would benefit from waterway conservation efforts or ecological rehabilitation efforts. With the impact the climate crisis is having on ecosystems, tracking the emergence of certain aquatic insects could serve to motivate and inform the public as to the effect humans are having on their local waterways.

The sea urchin Paracentrotus lividus, an eatable species of great commercial interest found in the Mediterranean and North-East Atlantic, is more vulnerable than so far believed.

This is stated in a study by the University of Barcelona, the Spanish National Research Council (CSIC) and the University of Tromsø (Norway) on the genetic distribution of populations of this species, led by the experts Marta Pascual, from the Faculty of Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona, and Xavier Turon, CSIC research professor at the Center for Advanced Studies of Blanes (CEAB-CSIC). The study has been recently published in the journal Diversity and Distributions.

Using a genetic analysis of the populations of this sea urchin, this work assesses its population structure and connectivity as a result of its dispersal ability. Scientists analysed about two-hundred and fifty individuals of Paracentrotus lividus from eleven marine areas, spanning from the French Atlantic coast to the eastern Mediterranean.

Researcher Xavier Turon (CEAB-CSIC) notes that "adult sea urchin barely move" and that dispersal occurs during the larval stage, since "when they are larvae, they swim in the plankton and are carried away by marine currents. We thought they had a high dispersal capability, since they have a long larval lifespan, which lasts for weeks".

What the study reveals is that "the dispersal is not as wide as we expected-says Turon- and geographical barriers such as the Strait of Gibraltar limit the connectivity of populations. The exchange of sea urchin larvae between different areas is more limited than what we thought".

Another shocking result is that the selection at a local level is having an impact on the genetic make-up of the different populations of urchins. "We found different allele composition among populations", note researchers Marta Pascual and Carles Carreras (UB-IRBio). "When we analysed the genetic sequences in which these differences appeared, we saw that they lay in genes that code for processes related to temperature and salinity". There is a strong selection pressure related to temperature in the Mediterranean, which can have important consequences regarding global warming.

The study reveals there is a progressive adaptation to salinity and temperature from west to east, and that the largest genetic differences are found between populations in the Atlantic and the Mediterranean. In the latter, the populations of western Mediterranean areas are also differentiated from those in the eastern Mediterranean.

Despite being the target of an active fishery, this species is very abundant in the Catalan coasts, since the fishing pressure has removed many of its predators (mainly fish). Urchins are herbivorous and eat seaweeds and seagrasses. With no predators, the populations can grow excessively and can eliminate submarine forests by overgrazing.

There are two main species of sea urchins in the littoral area of the Mediterranean: the eatable species Paracentrotus lividus, and the black sea urchin Arbacia lixula, non-edible. The new study brings new data to consider so as to predict potential future scenarios of how the common sea urchin populations will respond to antagonist pressures of predator removal and fishing, in a context of progressive warming.