Culture

Scientists in the Department of Biomedical Engineering at Texas A&M University are developing new ways to advance the field of regenerative medicine and cancer treatment. They are developing a 2D nanosheet that is 1,000 times smaller than a strand of hair.

Dr. Akhilesh Gaharwar, associate professor, has developed a new class of 2D nanosheets called molybdenum disulfide that can adsorb near infrared (NIR) light and modify cell behavior. These nanosheets are an emerging class of materials that have shown distinct physical and chemical properties due to their unique shape and size. Recently, some nanosheets have been explored for biomedical applications due to their light-responsive ability. Despite strong potential, Gaharwar's research is entering new territory, as few studies have investigated their cellular compatibility and none have explored their ability to modulate cellular functions using light.

To explore the possibility of controlling the cell response via light, Gaharwar's research group has synthesized an atomically thin nanosheet that can adsorb NIR light and convert it into heat. NIR light can penetrate deep inside the tissue compared to other types of light, including ultraviolet and visible light, and can be used to stimulate natural biological repair mechanisms in deep tissue.

Due to the high-surface area of nanosheets, they can stick to the outer membrane of cells and transmit a cellular signal to the nucleus, thereby controlling their behavior. Some of the nanosheets are also eaten by the cells and can influence cellular functions from inside.

"Light-responsive biomaterials have a strong potential for developing the next generation of noninvasive, precise and controllable medical devices for a range of biomedical applications, including drug delivery, cancer therapy, regenerative medicine and 3D printing," Gaharwar said.

His research was recently featured in the journal Proceedings of the National Academy of Sciences.

In collaboration with Dr. Irtisha Singh, assistant professor in the Department of Molecular and Cellular Medicine of the Texas A&M Health Science Center, Gaharwar's team used a next-generation sequencing technique to decipher the effect of light and/or nanosheets on the gene regulation of cells. Picture a cell as a blank canvas, and gene regulation as the paint that turns the canvas into something unique or interesting. For stem cells, that would mean determining what kind of cell they will be, such as muscle, bone, etc. Slight agitations in gene expression, either from light or these nanosheets, can significantly affect the functions of these cells such as movement, reproduction and expression.

Global gene expression profiles of cells reveal that light stimulation of the nanosheet can have a significant influence on cellular migration and wound healing. They demonstrated that cancer cells treated with a nanosheet and light are not able to move freely, which is good news. This is important as cancer spreads in the body by moving from one tissue to another. The combination of the nanosheet and light may provide new approaches to control and regulate cellular migration and functions.

The team found that the nanosheets bind to a cell surface receptor known as an integrin, a simple protein with a sugar attached. These integrin proteins are important in normal cell functioning by providing information to cells about its surroundings. If these proteins are covered by nanosheets, they cannot tell the cells to move around, effectively stopping the cells for an indefinite time.

Researchers in the USA have developed a graphene-based electrochemical sensor capable of detecting histamines (allergens) and toxins in food much faster than standard laboratory tests.

The team used aerosol-jet printing to create the sensor. The ability to change the pattern geometry on demand through software control allowed rapid prototyping and efficient optimization of the sensor layout.

Commenting on the findings, which are published today in the IOP Publishing journal 2D Materials, senior author Professor Mark Hersam, from Northwestern University, said: "We developed an aerosol-jet printable graphene ink to enable efficient exploration of different device designs, which was critical to optimizing the sensor response."

As an additive manufacturing method that only deposits material where it is needed and therefore minimizes waste, aerosol-jet-printed sensors are low-cost, straightforward to make, and portable. This could potentially enable their use in places where continuous on-site monitoring of food samples is needed to determine and maintain the quality of products, as well as other applications.

Senior author Professor Carmen Gomes, from Iowa State University, said: "Aerosol-jet printing was fundamental to the development of this sensor. Carbon nanomaterials like graphene have unique material properties such as high electrical conductivity, surface area, and biocompatibility that can significantly improve the performance of electrochemical sensors.

"But, since in-field electrochemical sensors are typically disposable, they need materials that are amenable to low-cost, high-throughput, and scalable manufacturing. Aerosol-jet printing gave us this."

The team created high-resolution interdigitated electrodes (IDEs) on flexible substrates, which they converted into histamine sensors by covalently linking monoclonal antibodies to oxygen moieties created on the graphene surface by a CO2 thermal annealing process.

They then tested the sensors in both a buffering solution (PBS) and fish broth, to see how effective they were at detecting histamines.

Co-author Kshama Parate, from Iowa State University, said: "We found the graphene biosensor could detect histamine in PBS and fish broth over toxicologically-relevant ranges of 6.25 to 100 parts per million (ppm) and 6.25 to 200 ppm, respectively, with similar detection limits of 2.52 ppm and 3.41 ppm, respectively. These sensor results are significant, as histamine levels over 50 ppm in fish can cause adverse health effects including severe allergic reactions - for example, scombroid food poisoning.

"Notably, the sensors also showed a quick response time of 33 minutes, without the need for pre-labelling and pre-treatment of the fish sample. This is a good deal faster than the equivalent laboratory tests."

The researchers also found the biosensor's sensitivity was not significantly affected by the non-specific adsorption of large protein molecules commonly found in food samples and used as blocking agents.

Senior author Dr Jonathan Claussen, from Iowa State University, said: "This type of biosensor could be used in food processing facilities, import and export ports, and supermarkets where continuous on-site monitoring of food samples is needed. This on-site testing will eliminate the need to send food samples for laboratory testing, which requires additional handling steps, increases time and cost to histamine analysis, and consequently increases the risk of foodborne illnesses and food wastage.

"It could also likely be used in other biosensing applications where rapid monitoring of target molecules is needed, as the sample pre-treatment is eliminated using the developed immunosensing protocol. Apart from sensing small allergen molecules such as histamine, it could be used to detect various targets such as cells and protein biomarkers. By switching the antibody immobilized on the sensor platform to one that is specific towards the detection of suitable biological target species, the sensor can further cater to specific applications. Examples include food pathogens (Salmonella spp.), fatal human diseases (cancer, HIV) or animal or plant diseases (avian influenza, Citrus tristeza)."

Experts from the University of Nottingham have discovered that some chimpanzees have a bone in their heart, which could be vital in managing their health and conservation.

Very few species of animals have this bone - called an os cordis - therefore this is a particularly rare find.

The exciting research, which was carried out by experts from the University's School of Veterinary Medicine and Science, is published today in Scientific Reports.

Wild chimpanzees are endangered and cardiovascular disease is very common in this species. Understanding their hearts is vital in making medical advances and managing their health and conservation.

The tiny 'os cordis' heart bones, measuring a few millimetres in size, were more likely to be present in chimps with idiopathic myocardial fibrosis - a type of heart disease found in chimps and people. Myocardial fibrosis is the most common type of heart disease in chimpanzees and has been linked to the occurrence of cardiac arrhythmias and sudden death.

"The discovery of a new bone in a new species is a rare event, especially in chimps which have such similar anatomy to people. It raises the question as to whether some people could have an os cordis too,' said lead author Dr Catrin Rutland from the University.

This astonishing new find was made possible using several techniques including an advanced imaging method called micro-computed tomography. This enabled the hearts to be scanned at much higher magnifications than standard hospital or veterinary CT scans.

"Looking for ways to help chimps with heart disease is essential. Understanding what is happening to their hearts helps us manage their health" Said Dr Sophie Moittié, from the University.

The heart bone is present in many bovines (cattle, ox and buffalo), and is often quite large, butchers even remove it some that meat can be used for soups. Sheep, otters, dogs and camels sometimes have the heart bone too. Sometimes the os cordis is present in most animals of a species but in other cases it is associated with heart disease.

The function of an os cordis is still being researched, but this work shows that cartilage was present in addition to bone, which gives insight into the mechanisms via which bone growth started. The scientists also showed that the heart bone was present in male and female chimps of differing ages.

Many suggestions have been given for the reasons behind an os cordis developing. The bone may support the essential heart valves, develop due to heart disease or even alter the electrical system which controls the heart.

"This research has brought together researchers and veterinary professionals, working on a common aim to advance chimpanzee health and conservation," adds Dr Rutland.

African Americans who smoke are nearly 2.5 times more likely to have a stroke than those who never smoked, while former smokers show a similarly lower risk as never smokers, according to a new study funded by the National Institutes of Health.

The findings from the Jackson Heart Study suggests that even after years of smoking, African Americans--who as a group are twice as likely as whites to have a stroke and die from it--could significantly reduce their risk if they kicked the habit. The study's findings, funded by the National Heart, Lung, and Blood Institute (NHLBI) and the National Institute for Minority Health and Health Disparities (NIMHD), both part of NIH, will appear online in the Journal of the American Heart Association.

Numerous studies have shown the link between smoking and stroke, but few have directly assessed the relationship solely in African Americans. This new study did that and also analyzed traditional risk factors for cardiovascular diseases and inflammation.

"This study provides further strong evidence of the link between cigarette smoking and stroke in African Americans," said David Goff, M.D., Ph.D., director of the Division of Cardiovascular Sciences at NHLBI. "We know that quitting smoking is one way to lower the risk for stroke, which is particularly important for the most vulnerable populations during this pandemic."

The study included 4,410 black men and women without a history of stroke and who were enrolled in the Jackson Heart Study, the largest study of cardiovascular disease in African Americans. Researchers classified the participants, who were 54 on average, into three groups based on their self-reported smoking history: current smokers, past smokers who smoked at least 400 cigarettes in their lifetimes, and never smokers.

The researchers further classified current smokers based on smoking intensity. One group included participants who smoked up to 19 cigarettes a day; another included those who smoked 20 or more cigarettes a day. Researchers followed participants from their initial evaluations beginning in 2000 through 2015.

At its start, the study included 781 past smokers, 546 current smokers, and 3,083 never smokers. By 2015, 5.2% of past smokers, 6.6% of those were smoking up to 19 cigarettes a day, and 7.2% of those smokers smoking more than 20 cigarettes a day had experienced a stroke, compared to 3.4% of never smokers.

After accounting for multiple risk factors for stroke, such as high blood pressure, diabetes, high "bad" cholesterol levels, and older age, researchers calculated that current smokers carried a risk for stroke that was more than double the risk for never smokers. And, the risk nearly tripled for those smoking 20 or more cigarettes each day. But past smokers showed an almost identical risk as never smokers.

"The bottom line is the more a person smokes, the greater their chance is of having a stroke," said Adebamike A. Oshunbade, M.D., M.P.H., the lead study author and postdoctoral research fellow at the University of Mississippi Medical Center. "It's important to communicate this risk to vulnerable populations, especially with the growing popularity of new tobacco products."

Michael E. Hall, M.D., associate professor of medicine at the University of Mississippi Medical Center, Jackson, and corresponding study author, agreed. He noted that while smoking has been shown in major studies to raise the risk of stroke 1.5 times for the general population, "these adverse health effects seem to be magnified in African Americans."
1In their analysis, the researchers also looked more closely at the already-established link between inflammation and atherosclerosis and smoking. They measured for C-reactive protein (CRP), a marker of inflammation, and carotid intima-media thickness, or CIMT, to assess the buildup of fatty plaques in the carotid arteries that supply blood to the brain.
1The researchers found that African American smokers who smoked 20 or more cigarettes a day had higher CIMT compared to never smokers. Researchers said this suggests that the buildup of plaque in the major blood vessels of the brains of African American smokers could play a role in the development of stroke.

Even before soaring unemployment caused millions of Americans to lose their health insurance, 18.2 million individuals at increased risk of severe COVID-19 were either uninsured or underinsured, according to a new study published today (June 10) in the Journal of General Internal Medicine by researchers at Harvard Medical School and CUNY's Hunter College. Although most of those at high medical and financial risk were white, racial minorities were over-represented.

Researchers determined who was at risk of severe COVID-19 based on age and medical risk factors such as diabetes. They found that Blacks, Native Americans, lower-income individuals of all races/ethnicities, and those residing in rural areas or in states that had not expanded Medicaid were doubly disadvantaged: they were both more likely to be at high risk of severe COVID-19 and to lack adequate coverage. For instance, compared to non-Hispanic whites, Blacks were 42% and Native Americans 90% more likely to be at risk for severe COVID-19, and high-risk persons from those racial groups were 51% and 53% more likely to have inadequate coverage compared to high-risk whites. Persons in states that failed to expand Medicaid were 6% more likely to be high risk, and 52% more likely to have inadequate coverage compared to those in states that accepted the ACA's Medicaid expansion. Hispanics at high medical risk were more than twice as likely as non-Hispanic whites to have inadequate coverage.

"The pandemic is laying bare the lethal inequality of American society and American health care," said lead author Dr. Adam Gaffney, a pulmonary and critical care physician at the Cambridge Health Alliance and Harvard Medical School. "Our ICU has been flooded with poor and minority patients; having COVID-19 is scary enough without worrying that you'll be bankrupted by medical bills," he added.

Despite recent federal actions to help fund COVID-19 care, and some insurers' promises to upgrade coverage for the disease, many American still lack protection from COVID-19's costs. The Families First Coronavirus Response Act mandated full coverage for COVID-19 testing, but not for treatment, and the CARES Act provided some funding for hospitals treating uninsured patients, but the protection is far from adequate. While some private insurers have promised to waive copays and deductibles for treatment as well as testing, this promise doesn't apply to out-of-network care, or to the majority of privately-insured workers whose employers are self-insured. Moreover, most of these waivers will expire by July 1. A Gallup poll found that many remain fearful of treatment costs, with 14% of Americans saying they would avoid care because of costs even if they develop symptoms of COVID-19.

"These promises of new protections for patients with COVID-19 are full of holes," noted senior author Dr. Danny McCormick, a primary care physician and associate professor at Harvard Medical School. "COVID-19 threatens the health of people everywhere, but only in the U.S. will it also ruin patients financially. When people avoid testing and care because they fear the costs, it fuels the epidemic's spread," he added.

The investigators also noted that the new federal legislation and insurers' promises won't help patients with COVID-19-like symptoms who are found to have a different diagnosis. "It's not just COVID care that's unaffordable," said co-author Dr. Steffie Woolhandler, Distinguished Professor of Public Health at CUNY's Hunter College and a Lecturer in Medicine at Harvard Medical School. "Patients with heart disease, asthma, and diabetes need protection too. Medicare for All is the long-term answer. But in the meantime, passage of the stopgap Medicare expansion bills introduced by Sen. Bernie Sanders and Rep. Pramila Jayapal would ensure that patients can get the care they need during the crisis, regardless of their diagnosis."

In a new study, Johns Hopkins researchers found that testing people for SARS-CoV-2 -- the virus that causes COVID-19 -- too early in the course of infection is likely to result in a false negative test, even though they may eventually test positive for the virus.

A report on the findings was published in the May 13 issue of Annals of Internal Medicine.

"A negative test, whether or not a person has symptoms, doesn't guarantee that they aren't infected by the virus," says Lauren Kucirka, M.D., Ph.D., M.Sc., obstetrics and gynecology resident at Johns Hopkins Medicine. "How we respond to, and interpret, a negative test is very important because we place others at risk when we assume the test is perfect. However, those infected with the virus are still able to potentially spread the virus."

Kucirka says patients who have a high-risk exposure should be treated as if they are infected, particularly if they have symptoms consistent with COVID-19. This means communicating with patients about the tests' shortcomings. One of several ways to assess for the presence of SARS-CoV-2 infection is a method called reverse transcriptase polymerase chain reaction (RT-PCR). These tests rapidly make copies of and detect the virus's genetic material. However, as shown in tests for other viruses such as influenza, if a swab misses collecting cells infected with the virus, or if virus levels are very low early during the infection, some RT-PCR tests can produce negative results. Since the tests return relatively rapid results, they have been widely used among high-risk populations such as nursing home residents, hospitalized patients and health care workers. Previous studies have shown or suggested false negatives in these populations.

For the new analysis, Johns Hopkins Medicine researchers reviewed RT-PCR test data from seven prior studies, including two preprints and five peer-reviewed articles. The studies covered a combined total of 1,330 respiratory swab samples from a variety of subjects including hospitalized patients and those identified via contact tracing in an outpatient setting.

Using RT-PCR test results, along with reported time of exposure to the virus or time of onset of measurable symptoms such as fever, cough and breathing problems, the researchers calculated the probability that someone infected with SARS-CoV-2 would have a negative test result when they had the virus infection. In the published studies, health care providers collected nasal and throat samples -from patients and noted the time of virus exposure or symptom -onset and sample collection.

From this data, the Johns Hopkins researchers calculated daily false-negative rates, and have made their statistical code and data publicly available so results can be updated as more data are published.

The researchers estimated that those tested with SARS-CoV-2 in the four days after infection were 67% more likely to test negative, even if they had the virus. When the average patient began displaying symptoms of the virus, the false-negative rate was 38%. The test performed best eight days after infection (on average, three days after symptom onset), but even then had a false negative rate of 20%, meaning one in five people who had the virus had a negative test result.

"We are using these tests to rule out COVID-19, and basing decisions about what steps we take to prevent onward transmission, such as selection of personal protective equipment for health care workers," says Kucirka. "As we develop strategies to reopen services, businesses and other venues that rely on testing and contact tracing, it is important to understand the limitations of these tests."

Ongoing efforts to improve tests and better understand their performance in a variety of contexts will be critical as more people are infected with the virus and more testing is required. The sooner people can be accurately tested and isolated from others, the better we can control the spread of the virus, the researchers say.

CORVALLIS, Ore. - An Oregon State University environmental engineering professor has solved a decades-old mystery regarding the behavior of fluids, a field of study with widespread medical, industrial and environmental applications.

The research by Brian D. Wood, published in the Journal of Fluid Mechanics, clears a roadblock that has been puzzling scientific minds for nearly 70 years and paves the way to a clearer picture of how chemicals mix in fluids.

A more complete grasp of that basic principle provides a foundation for advances in a range of areas - from how pollutants spread in the atmosphere to how drugs perfuse tissues within the human body.

Funded by the National Science Foundation, Wood's work with dispersion theory builds on research by one of the most accomplished scientists in Oregon State history, Octave Levenspiel. A 1952 chemical engineering Ph.D. graduate and later a longtime faculty member, Levenspiel in 1957 published an important paper on dispersion in chemical reactors on his way to becoming the college's first inductee to the National Academy of Engineering.

Even more importantly, the research by Wood bridges a longstanding gap in one of the fundamental tenets of fluid mechanics: Taylor dispersion theory. Named for British physicist and mathematician G.I. Taylor, author of a seminal 1953 paper, the theory concerns phenomena in which ?uctuations in a fluid's velocity ?elds cause chemicals to spread within it.

"The process of dispersive spreading tends to increase over time until it reaches a steady level," Wood said. "You can think of it as analogous to investment in a startup, in which the rates of return can initially be very large before settling in to a more sustainable level that is close to constant."

Taylor's theory was the first to allow researchers to predict that steady level of dispersion using what's known as the macroscopic dispersion equation. The equation can describe the net movement of a chemical species in a fluid -- provided enough time has elapsed from when the chemical entered the fluid.

"That was a signi?cant revelation at the time," Wood said. "It was on par with what researchers were doing theoretically in other disciplines, like quantum mechanics."

While Taylor's theory was successful and revolutionary, researchers still struggled with the problem of how dispersive spreading evolves from its dynamic, early behavior - what's termed as its initial condition - to when it attains the more constant value predicted by Taylor.

Scientists found some success by adding to the equation a time-dependent dispersion coe?cient, but the coefficient created problems of its own, the primary one being paradoxes.

"For example, if chemical solutes injected into a fluid at two di?erent times overlap, which time do you assign to the dispersion coe?cient?" Wood said. "Taylor himself understood that, where a time-dependent dispersion coe?cient was adopted, contemporary theories violated basic notions of causality in physics."

Wood and collaborators used another canon, the theory of partial di?erential equations, to show that problems with the time-dependent dispersion coefficient arose from neglecting the relaxation of the solute - the chemical injected into the fluid, or solution - from its initial condition.

"When chemical species are ?rst injected, their behavior is not necessarily consistent with a dispersion-type equation," Wood explained. "Rather, the initial condition first has to 'relax.' During this time, there is an additional term to account for that was missing in Taylor's macroscale dispersion equation."

In an equation, a term refers to a single number or a variable, or numbers and variables multiplied together.

The term Wood added corrects the dispersion equation to account for the initial con?guration of the chemical species moving around in the fluid. Somewhat surprisingly, Wood said, the theory also resolves paradoxes in other theories with time-dependent dispersion coe?cients.

"In the new theory, there is never a question about what dispersion coe?cient should be used when chemical solutes overlap," he said. "The adjustment to the spreading process is accounted for automatically by the presence of the additional term."

Metal-organic frameworks (MOFs) are unique micromaterial compounds consisting of a sponge-like network of metal ions or clusters linked together by organic linkers, and are able to store specific gas molecules in their pores. MOFs have such a high surface area due to their porosity that a single gram of the material has enough surface area to cover the size of a football field!

These super-sponges are used in research and industry to separate and store gases within tailor-made pockets, enabling their use in gas storage, separations, and sensing. Unlike traditional porous materials, MOFs can be modified as per need; in theory, their structure can be controlled through careful selection of the components of the synthesis process. But in practice, this process is challenged by the restricted synthetic conditions and high thermal and chemical sensitivity of MOFs. An attractive alternative is the post-synthetic modification (PSM) of MOFs.

Leading a team of scientists from Daegu Gyeongbuk Institute of Science and Technology (DGIST), Korea, Professor Jinhee Park approached this issue with the dual goals of giving desired functional groups to MOFs and introducing "mesoscopic" (bigger than microscopic) holes, which improve adsorption kinetics. Professor Park shares her convictions, stating, "We believe that this kind of study can facilitate the use of MOFs as a key material in environmental and energy related areas."

PSM through carbon-carbon bond formation has historically been difficult due to the lack of suitable reaction conditions that maintain the MOF structures. The scientists introduced stable carbon-carbon bonds by converting existing carbon-hydrogen bonds using elevated temperatures and adding "electrophilic organic halides or carbonyl compounds", allowing simultaneous introduction of the required functional groups as well as the mesoscopic holes.

Professor Park reports, "These results confirm the ability of the dual-PSM protocol to introduce desired alterations in MOFs while generating highly porous mesostructures." This technique could potentially improve the safety of workers in enclosed, gas-filled environments such as in the nuclear industry, and provide a more economically viable method of gas storage and purification.

In a world first, Edith Cowan University (ECU) researchers have discovered a plant that has successfully evolved to use ants - as well as native bees - as pollinating agents by overcoming their antimicrobial defences.

ECU PhD student Nicola Delnevo discovered the trait in a group of shrubs found the Swan Coastal Plain in Western Australia.

Mr Delnevo said ant pollination of plants was incredibly rare.

"Ants secrete an antimicrobial fluid that kills pollen grain," he said.

"So ants have traditionally been considered to be a menace -- nectar thieves whose aggression keeps other potential pollinating insects at bay.

"However this group of plants in WA, commonly known as the Smokebush family (Conospermum), has evolved a way to use ants to their advantage."

Mr Delnevo tested the effect of the antimicrobial secretion from three ant species found locally on the flowers of six WA plant species, with startling results.

"We found evidence that Conospermum plants have adapted the biochemistry of their pollen grains to cope with the antimicrobial properties of the ants.

"This is the first plant species found to have adapted traits that enables a mutually beneficial relationship with ants," Mr Delnevo said.

"About 46 examples of ant pollination have been documented around the world, but these have been due to the ants producing less toxic secretions that allow them to pollinate."

No help from honeybees

Mr Delnevo said the pollination by ants was particularly good news for these plants as they were unable to rely on honeybees.

"Conospermum plants have unscented tubular flowers that are too narrow for honeybees wriggle inside to pollinate," Mr Delnevo explained.

"They rely on native insects carrying a suitable pollen load from visiting other flowers for pollination to occur.

"They have co-evolved with a native bee (Leioproctus conospermi) that has evolved as a specialist feeder of these flowers.

"This relationship is mutually beneficial, but it would be risky in an evolutionary sense for the plant to rely solely on the native bee for pollination."

Future research will explore how common ant pollination is amongst the flora of south-western Australia and exactly how this trait of overcoming ant defences has evolved.

Population-wide use of facemasks keeps the coronavirus 'reproduction number' under 1.0, and prevents further waves of the virus when combined with lockdowns, a modelling study from the universities of Cambridge and Greenwich suggests.

The research suggests that lockdowns alone will not stop the resurgence of SARS-CoV-2, and that even homemade masks with limited effectiveness can dramatically reduce transmission rates if worn by enough people, regardless of whether they show symptoms.

The researchers call for information campaigns across wealthy and developing nations alike that appeal to our altruistic side: "my facemask protects you, your facemask protects me". The findings are published in the Proceedings of the Royal Society A.

"Our analyses support the immediate and universal adoption of facemasks by the public," said lead author, Dr Richard Stutt, part of a team that usually models the spread of crop diseases at Cambridge's Department of Plant Sciences.

"If widespread facemask use by the public is combined with physical distancing and some lockdown, it may offer an acceptable way of managing the pandemic and re-opening economic activity long before there is a working vaccine."

Dr Renata Retkute, coauthor and Cambridge team member, said: "The UK government can help by issuing clear instructions on how to make and safely use homemade masks."

"We have little to lose from the widespread adoption of facemasks, but the gains could be significant."

The new coronavirus is transmitted through airborne droplets loaded with SARS-CoV-2 particles that get exhaled by infectious people, particularly when talking, coughing or sneezing.

For the latest study, Cambridge researchers worked to link the dynamics of spread between individuals with population-level models, to assess different scenarios of facemask adoption combined with periods of lockdown.

The modelling included stages of infection and transmission via surfaces as well as air. Researchers also considered negative aspects of mask use, such as increased face touching.

The reproduction or 'R' number - the number of people an infected individual passes the virus onto - needs to stay below 1.0 for the pandemic to slow.

The study found that if people wear masks whenever they are in public it is twice as effective at reducing 'R' than if masks are only worn after symptoms appear.

In all modelling scenarios, routine facemask use by 50% or more of the population reduced COVID-19 spread to an R less than 1.0, flattening future disease waves and allowing less-stringent lockdowns.

Viral spread reduced further as more people adopted masks when in public. 100% mask adoption combined with on/off lockdowns prevented any further disease resurgence for the 18 months required for a possible vaccine.

The models suggest that - while the sooner the better - a policy of total facemask adoption can still prevent a second wave even if it isn't instigated until 120 days after an epidemic begins (defined as the first 100 cases).

The team investigated the varying effectiveness of facemasks. Previous research shows that even homemade masks made from cotton t-shirts or dishcloths can prove 90% effective at preventing transmission.

The study suggests that an entire population wearing masks of just 75% effectiveness can bring a very high 'R' number of 4.0 - the UK was close to this before lockdown - all the way down to under 1.0, even without aid of lockdowns.

In fact, masks that only capture a mere 50% of exhaled droplets would still provide a "population-level benefit", even if they quadrupled the wearer's own contamination risk through frequent face touching and mask adjustment (a highly unlikely scenario).

The researchers point out that crude homemade masks primarily reduce disease spread by catching the wearer's own virus particles, breathed directly into fabric, whereas inhaled air is often sucked in around the exposed sides of the mask.

"There is a common perception that wearing a facemask means you consider others a danger," said Professor John Colvin, coauthor from the University of Greenwich. "In fact, by wearing a mask you are primarily protecting others from yourself."

"Cultural and even political issues may stop people wearing facemasks, so the message needs to be clear: my mask protects you, your mask protects me."

"In the UK, the approach to facemasks should go further than just public transport. The most effective way to restart daily life is to encourage everyone to wear some kind of mask whenever they are in public," Colvin said.

Prof Chris Gilligan, coauthor from Cambridge's Epidemiology and Modelling Group in the Department of Plant Sciences, added: "These messages will be vital if the disease takes hold in the developing world, where large numbers of people are resource poor, but homemade masks are a cheap and effective technology."

The first confirmed heartbeat of a supermassive black hole is still going strong more than ten years after first being observed.

X-ray satellite observations spotted the repeated beat after its signal had been blocked by our Sun for a number of years.

Astronomers say this is the most long lived heartbeat ever seen in a black hole and tells us more about the size and structure close to its event horizon - the space around a black hole from which nothing, including light, can escape.

The research, by the National Astronomical Observatories, Chinese Academy of Sciences, China, and Durham University, UK, appears in the journal Monthly Notices of the Royal Astronomical Society.

The black hole's heartbeat was first detected in 2007 at the centre of a galaxy called RE J1034+396 which is approximately 600 million light years from Earth.

The signal from this galactic giant repeated every hour and this behaviour was seen in several snapshots taken before satellite observations were blocked by our Sun in 2011.

In 2018 the European Space Agency's XMM-Newton X-ray satellite was able to finally re-observe the black hole and to scientists' amazement the same repeated heartbeat could still be seen.

Matter falling on to a supermassive black hole as it feeds from the accretion disc of material surrounding it releases an enormous amount of power from a comparatively tiny region of space, but this is rarely seen as a specific repeatable pattern like a heartbeat.

The time between beats can tell us about the size and structure of the matter close to the black hole's event horizon.

Professor Chris Done, in Durham University's Centre for Extragalactic Astronomy collaborated on the findings with colleague Professor Martin Ward, Temple Chevallier Chair of Astronomy.

Professor Done said: "The main idea for how this heartbeat is formed is that the inner parts of the accretion disc are expanding and contracting.

"The only other system we know which seems to do the same thing is a 100,000 times smaller stellar-mass black hole in our Milky Way, fed by a binary companion star, with correspondingly smaller luminosities and timescales.

"This shows us that simple scalings with black hole mass work even for the rarest types of behaviour."

Lead author Dr Chichuan Jin of the National Astronomical Observatories, Chinese Academy of Sciences, said: "This heartbeat is amazing!

"It proves that such signals arising from a supermassive black hole can be very strong and persistent. It also provides the best opportunity for scientists to further investigate the nature and origin of this heartbeat signal."

The next step in the research is to perform a comprehensive analysis of this intriguing signal, and compare it with the behaviour of stellar-mass black holes in our Milky Way.

A simple and low-cost method of 'listening' to chicks may allow welfare issues to be picked up at the earliest possible opportunity, according to new research.

In commercial chicken farming, thousands of newly-hatched chicks are reared in batches. A team of animal welfare and behaviour scientists from across the UK collected acoustic recordings in 12 typical such flocks of 25,000 chicks.

In nature, when uncomfortable or uncertain of their surroundings, chicks would attract the hen with a loud and distinctive distress call.

In this study, the researchers demonstrated that these calls could be clearly picked up above other noises such as regular calling and farm machinery.

But where previous research has linked distress calling to stress and anxiety-like states in chicks, this study also shows it could predict flock-level behaviour, future growth and mortality rate.

That suggests distress calling may be an 'iceberg indicator' - a single measure that captures a range of welfare information at once.

The study, published in the Journal of the Royal Society Interface, involved researchers from the University of Plymouth, University of Roehampton, SRUC, and Newcastle University. It was funded by the Biotechnology and Biological Sciences Research Council in an Innovate UK partnership with Greengage Lighting Ltd.

Lead author Dr Katherine Herborn, Lecturer in Physiology and Behaviour at the University of Plymouth, said: "On their first day in a barn, all chicks are going to call because they are in strange surroundings. But after that they learn where to find food and water and settle into that new world, so if you are still hearing a lot of distress calling after a few days it could be a sign there is something wrong. With over 50 billion birds being produced each year, tools to support simple interventions at the right time could potentially have big impacts on welfare and quality of life for these birds."

Lucy Asher, Professor in Animal Behaviour Informatics at Newcastle University and Principal Investigator on the BBSRC project, added: "By analysing the calls chicks make in their first few days of life, it seems we are able to predict weight gained and the number of deaths in the whole flock for the whole life. This means we could have a very powerful tool to help chicken welfare. What is particularly useful is that this welfare indicator can be used early on in life, whereas most chicken welfare indicators are taken later in their life when it is too late to make major improvements. As an added benefit this study shows how we can measure chick calls automatically, meaning no extra work for farmers, but more information to help them improve chicken welfare."

The method used in the research involved measuring the 'spectral entropy' of the soundscape -a value that describes how sound can vary from a clear, tonal note up to white noise.

As increasing numbers of chicks call in unison, the usual background noise of the farm becomes overall more tonal. This computationally simple way of counting distress calls could act as an early-warning signal to farm staff that chicks require attention and ultimately improve chick welfare across their lifetimes.

The findings support previous studies on the benefits of automated monitoring of livestock for real-time warnings of emerging welfare concerns. They also emphasise the importance of using animal-centred behavioural and emotional welfare indicators alongside traditional environment and productivity monitoring on poultry farms, to improve conditions from the birds' own perspective.

Dr Alan McElligott, Reader in Animal Behaviour at the University of Roehampton, added: "The results of this research show how useful vocalisations can be for monitoring welfare, and especially in an age when animal welfare needs should be central to progress in precision livestock farming."

Below please find a summary and link(s) of new coronavirus-related content published today in Annals of Internal Medicine. The summary below is not intended to substitute for the full article as a source of information. A collection of coronavirus-related content is free to the public at http://go.annals.org/coronavirus.

When the Dust Settles: Preventing a Mental Health Crisis in COVID-19 Clinicians

On 26 April, after spending weeks caring for patients with COVID-19 in New York City, emergency room physician Lorna Breen took her own life. Her grieving family recounts days of helplessness leading up to this as Dr. Breen described how COVID-19 upended her emergency department and left her feeling inadequate despite years of training and expertise. Authors from Harvard Medical School and Dana-Farber Cancer Institute describe timely and targeted actions that clinicians can take during the COVID-19 pandemic to prevent a mental health crisis in these overextended and stressed essential workers. Read the full text: https://www.acpjournals.org/doi/10.7326/M20-3738.

Media contacts: A PDF for this article is not yet available. Please click the link to read full text. The lead author, Stephanie Kiser, MD, MPH, can be reached through Claire Monaghan at Claire_Monaghan@DFCI.HARVARD.EDU or Ellen Berlin at Ellen_Berlin@DFCI.HARVARD.EDU .

Kaitlin (Katie) Gold is an assistant professor within the Plant Pathology and Plant-Microbe Biology section of the School of Integrative Plant Science at Cornell University. At her lab, the Grape Sensing, Pathology, and Extension Lab at Cornell AgriTech (GrapeSPEC), she studies the fundamental and applied science of plant disease sensing. The GrapeSPEC Lab uses proximal and remote spectroscopy, data science, and fundamental plant pathology to improve the three pillars of integrated grape disease management: understanding pathogen biology, host susceptibility, and fungicide efficacy.

Though she now focuses on grapes, Gold and colleagues at the University of Wisconsin-Madison recently published research showing how they used contact spectroscopy to non-destructively sense how plant pathogens differentially damage, impair, and alter plant traits during the course of infection. This research centered on late blight of potato and tomato. The hyperspectral sensors Gold and colleagues used measure light reflectance in the visible to shortwave infrared range of the electromagnetic spectrum- 7x more wavelengths than the human eye can see.

"We previously found that this technology could be used to pre-symptomatically detect late blight infection in potato," Gold explained. Late blight pathotypes are defined as clonal lineages and asexual descendants of a single genotype. In their latest research, they paired machine learning-based hyperspectral analysis with a molecular assay (qrt-PCR) to better understand what pathogen processes might be the root cause of their ability to discriminate between clonal lineages.

They found that they could use hyperspectral sensors to accurately differentiate between these two late blight clonal lineages.

"Surprisingly, we find that our ability to differentiate between them was more accurate at the earliest stages of infection: before symptoms appeared rather than after," said Gold. "Using qrt-PCR, we found modest evidence to support that this ability may be linked to differences in pre-symptomatic effector expression between the two lineages. This is the first time hyperspectral sensors have been used to distinguish between pathotypes and is an important step forward for the discipline of plant disease sensing."

This proof of concept work sets a roadmap for the future use of hyperspectral sensors as automated, non-destructive, and scalable tools to identify pathotype in real time, in both late blight and other pathosystems.

"Spectroscopy is one of the only diagnostic technologies that is both scalable and has a passive monitoring capacity. Current methods to determine late blight clonal lineage require active, destructive sampling. Despite being at the earliest stages of development, this work opens a door to a world where hyperspectral sensors could one day be used to passively detect different pathotypes in the field at scale."

Asked for her thoughts about this research, Gold said, "This work was my favorite dissertation chapter and was truly a joy to do. I loved that we were able to pair this 'space age-esque' technology with a classic plant pathology diagnostic method."

The formation of our solar system was a messy affair. Most of the material that existed before its formation -- material formed around other, long-dead stars -- was vaporized, then recondensed into new materials. But some grains of that material, formed before the sun's birth, still persist.

These "stardust" grains arrived on Earth inside primitive meteorites. New Washington University in St. Louis research led by Nan Liu, an assistant research professor in physics and the Laboratory for Space Sciences in Arts & Sciences, shows that stardust was also delivered to another planet-like body in the solar system, asteroid 4 Vesta, by micrometeoroids that also carried water.

The research was published in the journal Geochimica et Cosmochimica Acta.

"Like our Earth," Liu said, "Vesta has a core, a mantle and crust," features that formed as the materials melted, differentiated and coalesced into a single planet-like object. And like Earth, Vesta is also pummeled by micrometeoroids. The brightest asteroid in the night sky, Vesta orbits the sun in the asteroid belt between Mars and Jupiter.

Liu, along with Lionel Vacher, a postdoctoral researcher, and Ryan Ogliore, assistant professor of physics, studied samples of the Kapoeta meteorite for this research. Kapoeta fell to Earth in 1942 in what is now South Sudan, landing on a road in front of a British convoy during World War II. NASA's Dawn mission to asteroid Vesta established a link between Vesta and the howardites, eucrites and diogenites, groups of meteorites found on Earth.

The research team focused on small, dark inclusions in Kapoeta that seemed out of place, like pieces of clay in lava rock. "They look completely different from surrounding material," Liu said. They turned out to be microscopic meteoroids, less than 100 microns across (smaller than the thickness of a human hair), that landed on Vesta's surface.

Liu used the university's mass-spectrometer microscope, the NanoSIMS, to search the inclusions for presolar material. Because stardust has a very different isotopic composition from material that formed within the solar system, it jumped out at her under the microscope.

The stardust in asteroid Vesta is a unique record of ancient, galactic material delivered long ago to a body far from Earth. The researchers postulate that the micrometeoroids arrived at Vesta after the violent impacts of the Late Heavy Bombardment, about 3.5 billion years ago.

Vacher and Ogliore measured the chemical compositions of the micrometeoroids to understand in what type of environment they formed. They recognized minerals and textures that were linked to interactions between rock and water from melted ice.

One of the big questions is: How did water get on Earth?

"We need a mechanism to bring ice from the outer solar system, where the temperature is low," Vacher said. "This research shows that you can transport small micrometeoroids that contain ice to dry bodies that formed without water."

The ancient record of these micrometeoroids impacting Earth has been erased by weather and plate tectonics. The micrometeoroid record from asteroid Vesta may help to explain how water was delivered to the young Earth.

"If icy micrometeoroids delivered water to the inner solar system when the Earth was still forming, this could be one way that the Earth ended up with enough water to support life," Ogliore said. "Habitable planets around other stars may have acquired their water through similar means."

More analyses are needed to determine the when and the where. "Our next measurements will constrain when this wet material was delivered to Vesta, and where it came from: an icy asteroid, a comet or some other exotic source," Ogliore said.

Take a trip to 4 Vesta

You can zoom in on Kapoeta thanks to Ryan Ogliore, assistant professor of physics. He worked to develop techniques to visualize objects from the micrometer to the millimeter scale -- that's a factor of 1,000. "It's like he took a puzzle with 1,000 pieces, but Ryan is doing the same puzzle with 10,000 pieces," said Lionel Vacher, research assistant. Click here to visit the meteorite: https://bit.ly/3dPqord