Culture

After comparing how infections from SARS-CoV-2 (which causes COVID-19) and two other human coronaviruses develop in cynomolgus macaques, researchers report that SARS-CoV-2 gives the animals a mild COVID-19-like disease. The results - based on a combination of experimental and historical infection data - suggest these animals are a promising model for testing COVID-19 therapeutics. Treatments for COVID-19 are urgently needed, as are animal models to test them. Which animal(s) can be used most precisely to model the efficacy of control measures in humans remains a question. To better understand key pathways in the pathogenesis of SARS-CoV-2, Barry Rockx et al. infected young and old cynomolgus macaques with SARS-CoV-2 (from a strain from a German traveler returning from China), as well as with MERS-CoV, comparing their results with historical reports of infections by SARS-CoV. All experiments were performed under Biosafety Level-3 conditions. SARS-CoV-2 leads to mild infection with little to no symptoms, the authors report, even as animals infected were shedding the virus; this is similar to how asymptomatic humans shed the SARS-CoV-2 virus. Viral RNA was detected at higher levels and for longer duration in older macaques, the authors report, though none showed the severe symptoms that older humans do. Also, like influenza, the animals shed the virus from the respiratory tract very early during infection as compared to with SARS-CoV; this could explain the explosive global spread of COVID-19 and why case detection and isolation may not be as effective as it was for controlling SARS-CoV. The macaques infected with MERS-CoV did not develop notable symptoms during study period. "This study provides a novel infection model which will be critical in the evaluation and licensure of preventive and therapeutic strategies against SARS-CoV-2 infection for use in humans," write the authors.

A recently developed system for switching on the activity of genes could improve treatments for a broad range of neurological diseases. Esteban Engel, a researcher in viral neuroengineering in the Princeton Neuroscience Institute, and his team have developed new gene promoters - which act like switches to turn on gene expression - that promise to broaden the ability to deliver large genes and keep them active for long periods of time.

The research was published online this week in the journal Molecular Therapy: Methods & Clinical Development.

The team is developing these genetic switches for use in gene therapy, the practice of delivering new genes to replace or assist ones that are faulty. Gene therapy is a promising strategy for many diseases, including disorders that involve the brain, such as Parkinson's disease and Alzheimer's disease.

To carry genes into cells, scientists take advantage of the fact that viruses come equipped with the machinery to gain entry to cells. Over the years, scientists have engineered viruses to deliver genes in ways that are safe and don't cause disease. One of the viruses commonly used for this is the relatively harmless adeno-associated virus (AAV).

Engel and his team created new gene promoters that turn on genes after they have been transported into neurons - the cells of the brain and nervous system. The team designed their promoters by adopting attributes of promoters found in another class of viruses, the herpes viruses, which persist for years in the body by establishing a chronic infection in the nervous system.

The team's engineered promoters occupy far less space than existing promoters used in gene therapy, allowing the transport of larger genes or multiple genes. The new promoters are also long-lasting, being less prone to repression or inactivation than most common promoters, so the therapeutic genes are active for long periods of time. These new promoters work with AAV as well as other viral and non-viral gene-delivery systems.

"These new promoters will allow us to deliver larger genes or multiple small genes," Engel said, "and the genes can remain active for as long as they are needed."

In this Special Issue of Science, five Reviews highlight new insights into the impacts of drought on social, ecological and agricultural systems worldwide. Political fragmentation in how community water systems are managed in the United States contributes to disparities in water security in American communities and households, says Megan Mullin in one Review. Even though, by global standards, most Americans have reliable access to safe drinking water, access to clean water is still unequal within the country, particularly in the nation's rural and impoverished communities. This inequality is made worse by the ever-growing risk of drought, says Mullin; increasing drought can push most communities to the brink of their water supplies. Identifying and addressing weaknesses in water management policy is a crucial step towards ensuring water security for all Americans, Mullin says. Toby Ault highlights the various definitions and physical causes of drought and the analytical tools that enable us to evaluate and predict drought risks in another Review. In a third, Timothy Brodribb and colleagues discuss the vulnerability of Earth's forests as many regions become hotter and drier; according to Brodribb et al., many long-lived tree species may be particularly susceptible to damage via water stress. Aditi Gupta and colleagues discuss our current understanding of how plants alter their physiology to adapt to water insufficiency - research that is informing the development of high-yield, drought-resistant crops. In a final Review, Franciska De Vries and colleagues discuss the growing body of research highlighting the importance of soil microbiota in endowing plants with resilience to environmental stressors; understanding how crop plant microbiota responses buffer drought may enable sustainable food production on a drier planet.

A single error in cell division related to the formation of a chromosome bridge can trigger a cascade of mutational events, rapidly generating many of the defining features of cancer genomes, a new study suggests. The findings provide a potential mechanistic explanation for the extreme genomic complexity and chromosomal rearrangements found in certain tumor types. It's been assumed that cancer genomes acquire their complexity gradually, accumulating small-scale changes over time through unavoidable errors during DNA replication. However, some studies have suggested that cancer genomes may also evolve rapidly through one-off catastrophic mutational events that generate bursts of genomic alterations. Researchers know the scrambled genomes of cancer cells can arise quickly via several mutational processes, including the chromosome breakage-fusion-bridge (BFB) cycle and chromothripsis - a highly local, yet massive rearrangement in one or several chromosomes. Recent studies have suggested that these two catastrophic mutational processes may be mechanistically related. To evaluate their relationship, Neil Umbreit and colleagues recreated the essential steps of the BFB cycle in cultured cells and used live cell imaging and single-cell whole-genome sequencing to observe the downstream genetic repercussions of aberrant cell division, specifically of aberrant chromosome bridge formation. Umbreit et al. discovered that this single error during one cell division triggered a mutational avalanche that generated increasing amounts of chromothripsis, resulting in rapid and extensive DNA damage. In a related Perspective, Jacob Paiano and André Nussenzweig discuss the study in greater detail.

Health and nutrition experts recommend that children do not consume drinks with added sugars or nonnutritive sweeteners, yet drinks containing both represent a major portion of beverages consumed by children. One reason may be that the labels of drinks marketed to kids do not help parents and other consumers differentiate among fruit juice and sugar-laden, artificially flavored drinks, finds research from NYU School of Global Public Health.

While the FDA regulates drink labels, it permits a wide range of names, claims, and fruit images on packaging that do not necessarily reflect the drink's ingredients. For example, more than 60 percent of drinks with added sugar include a positive nutrition claim about sweeteners, while more than a third of drinks with fruit pictured on the packaging do not include juice from any of the fruits shown.

The study, published in the American Journal of Public Health, recommends that the Food and Drug Administration (FDA) revise its labeling regulations to help consumers make healthier choices.

"Given the many different drinks marketed to children that contain or appear to contain juice, it is important that caregivers are able to differentiate among products and identify healthier options," said Jennifer Pomeranz, assistant professor of public health policy and management at NYU School of Global Public Health and the study's lead author.

Pomeranz and her colleague Jennifer Harris, senior research advisor, Rudd Center for Food Policy & Obesity at the University of Connecticut, examined the labels and ingredients of top-selling children's juice drinks, including brands with at least $10 million in annual sales. To compare similar products across brands and categories, they focused on "fruit punch" flavored drinks.

The researchers identified 39 fruit punch flavored drinks that widely varied in the amount of juice they contained: seven contained 100 percent juice, 11 were diluted juices (juice and water), eight contained some juice (less than 100 percent but more than 2 percent) with added sugars or low-calorie sweeteners, eight had no or almost no juice (2 percent or less) and consisted of flavoring and sugar or low-calorie sweeteners, and five called themselves water but had similar ingredients as the drinks with little or no juice.

While the FDA requires products with 100 percent juice to include statements on the packaging related to added sweeteners, products with less than 100 percent juice are not required to have the same disclosures. Without this required transparency, the researchers observed many different nutrition claims on beverages.

Of the products containing added sugars--which came from all categories except 100 percent juice and diluted juice--60 percent touted positive statements about sweeteners such as "no high fructose corn syrup."

Drinks containing stevia extract--a plant-derived sweetener--included claims such as "no artificial sweeteners" and "no sugar added."

Drinks across all categories had vitamin claims such as "100% vitamin C," even though this was due to fortification and not derived from fruit juice.

Nearly all drinks (97 percent) showed images of fruit on the front of the package, even if they did not contain juice from the fruits pictured--or any juice at all. The researchers found that even though labels depicted 19 different types of fruit, apple juice was the primary juice across products containing juice as an ingredient. While less than half (45 percent) of drinks with fruit images on the package actually included juice from the pictured fruits, more than a third (37 percent) did not contain juice from any of the fruits on the packaging.

"We identified numerous labeling practices that obscure the true nature of drinks trying to pass as juice, blurring the distinction between drinks that are acceptable for children and those containing added sugar or sweeteners," added Pomeranz. "Nonetheless, these practices align with current FDA regulations, which allow the naming and use of fruit images that reflect the drink's flavor, regardless of the product's ingredients."

The researchers recommend several changes to FDA regulations in order to help consumers make healthier choices, including standardizing the names of products (juice vs. waters vs. drinks with added sweeteners), differentiating between flavors and ingredients, and prominently disclosing added sweeteners on the front of products.

"The FDA should make it easier for consumers to tell what products are healthy for children--without having to carefully inspect the nutrition panel and decipher each ingredient on the back of the package," said Pomeranz.

SINGAPORE, 16 April 2020 - A newly-discovered small protein in mitochondria is essential for energy production, report Duke-NUS researchers and their colleagues in the journal Nature Communications. Zebrafish lacking the small protein, which the scientists named BRAWNIN, have similar features to rare mitochondrial diseases in humans, suggesting further studies of the protein could help explain these conditions and identify possible therapies.

The international research team, led by cell and developmental biologist Lena Ho, an Assistant Professor at Duke-NUS Medical School's Cardiovascular and Metabolic Disorders Programme, discovered 16 'short open reading frame-encoded peptides' (SEPs) whose genetic code is translated in the nucleus, but which are then imported into mitochondria, the power-generating structures of cells.

"SEPs have been fascinating the scientific community for several years now, as they represent a mini-proteome that has never been explored; a repository of new gene functions," said Dr Ho. "But there haven't been systematic studies to validate their functions and biological relevance. We found that the mitochondria are a hotspot for their functions, for reasons we don't completely yet understand."

The scientists singled out one of the 16 mitochondrial SEPs they discovered for further analysis. Knocking out the gene that codes for the SEP, which they named BRAWNIN, in zebrafish led to extreme growth retardation and lactic acid accumulation in cells. Further tests revealed that BRAWNIN was essential for the assembly of a group of molecules in the mitochondria called respiratory chain complex III. This molecular complex is essential for all life forms that use oxygen for energy generation, according to Dr Ho.

The team is now trying to understand how exactly BRAWNIN is involved in complex III assembly. They are also investigating which diseases could be predisposed to by BRAWNIN malfunction and how useful the protein might be as a target to reverse their pathologies.

"Mitochondrial decline and dysfunction underlies all degenerative diseases and has been widely implicated in cancer," Dr Ho said. "The proteins we've discovered, including BRAWNIN, represent potential targets for reversing mitochondrial decline."

Duke-NUS' Senior Vice Dean for Research, Prof Patrick Casey, commented on the discovery: "Degenerative diseases and cancer are major health concerns in Singapore and around the globe. The insights gained from Asst Prof Ho's study reaffirms the value of our commitment to fundamental scientific research that can potentially help solve some of these problems."

Dr Ho also noted there are 15 more mitochondrial SEPs to investigate. "We are actively looking for collaborators who are interested in studying them," she added.

A support programme that aims to boost retention in the Armed Forces has received a positive research evaluation from Anglia Ruskin University (ARU), with military personnel reporting increased confidence in their employment prospects and increased goodwill towards the Armed Forces.

A pilot of the Spouse Employment Support (SES) programme was delivered from 2015-2017 by the Ministry of Defence to try and address some of the issues facing military spouses.

Previous research has found that the transient nature of military life, particularly in the Army where transfers between barracks occur with regularity, can have a negative impact on the careers of spouses, who often have to uproot at short notice.

Common issues include interruption to higher education, negative impact on career progression, and difficulty starting again in new areas, particularly if they are employed in a specialist field or if they have had a break from work.

These problems can in turn breed resentment of military life, which has a knock-on effect on retention of personnel.

The SES helped military spouses search for and find employment by providing training grants of up to £879 and specialist career support. The pilot was open to 195 spouses of RAF personnel across 22 bases in the UK, and 240 spouses of Joint Forces Command across four locations in Cyprus.

The evaluation, carried out by ARU's Veterans and Families Institute for Military Social Research (VFI) and published in the journal Military Psychology, consisted of 30-minute interviews with spouses and military personnel.

Two thirds of military spouses reported increased confidence, while around a third said they felt valued and supported by the military, and that taking part in the SES trial had increased their employability.

One partner of an RAF Corporal based in Cyprus said: "Any sort of recognition, of the fact that it's difficult to find work makes people feel better. I don't think people realise the fact that you sacrifice your family, your career, your personal life essentially. Because you're forced to move around constantly."

Author of the evaluation, Dr Lauren Godier-McBard at ARU, said: "There was a strong indication from the interviews we carried out that the support given by the SES was of benefit to military spouses and, indirectly, their serving partners.

"Simply accessing this support and beginning to think about employment and their career aspirations prompted a number of spouses to become more proactive in engaging with the job market and planning their career.

"Furthermore, our results have highlighted the value placed by military spouses of being recognised by the military as valued constituents in their own right. Some of the serving partners indicated that their spouses appeared happier with military life as a result of the support and training they had received."

"It's not rocket science" may be a tired cliché, but that doesn't mean designing rockets is any less complicated.

Time, cost and safety prohibit testing the stability of a test rocket using a physical build "trial and error" approach. But even computational simulations are extremely time consuming. A single analysis of an entire SpaceX Merlin rocket engine, for example, could take weeks, even months, for a supercomputer to provide satisfactory predictions.

One group of researchers at The University of Texas at Austin is developing new "scientific machine learning" methods to address this challenge. Scientific machine learning is a relatively new field that blends scientific computing with machine learning. Through a combination of physics modeling and data-driven learning, it becomes possible to create reduced-order models - simulations that can run in a fraction of the time, making them particularly useful in the design setting.

The goal of the work, led by Karen Willcox at the Oden Institute for Computational Engineering and Sciences, is to provide rocket engine designers with a fast way to assess rocket engine performance in a variety of operating conditions.

"Rocket engineers tend to explore different designs on a computer before building and testing," Willcox said. "Physical build and test is not only time-consuming and expensive, it can also be dangerous."

But the stability of a rocket's engine, which must be able to withstand a variety of unforeseen variables during any flight, is a critical design target engineers must be confident they have met before any rocket can get off the ground.

The cost and time it takes to characterize the stability of a rocket engine comes down to the sheer complexity of the problem. A multitude of variables affect engine stability, not to mention the speed at which things can change during a rocket's journey.

The research by Willcox is outlined in a recent paper co-authored by Willcox and published online by AIAA Journal. It is part of a Center of Excellence on Multi-Fidelity Modeling of Rocket Combustion Dynamics funded by the Air Force Office of Scientific Research and Air Force Research Laboratory.

"The reduced-order models being developed by the Willcox group at UT Austin's Oden Institute will play an essential role in putting rapid design capabilities into the hands of our rocket engine designers," said Ramakanth Munipalli, senior aerospace research engineer in the Combustion Devices Branch at Air Force Rocket Research Lab. "In some important cases, these reduced-order models are the only means by which one can simulate a large propulsion system. This is highly desirable in today's environment where designers are heavily constrained by cost and schedule."

The new methods have been applied to a combustion code used by the Air Force known as General Equation and Mesh Solver (GEMS). Willcox's group received "snapshots" generated by running the GEMS code for a particular scenario that modeled a single injector of a rocket engine combustor. These snapshots represent the instantaneous fields of pressure, velocity, temperature and chemical content in the combustor, and they serve as the training data from which Willcox and her group derive the reduced-order models.

Generating that training data in GEMS takes about 200 hours of computer processing time. Once trained, the reduced-order models can run the same simulation in seconds. "The reduced-order models can now be run in place of GEMS to issue rapid predictions," Willcox said.

But these models do more than just repeat the training simulation.

They also can simulate into the future, predicting the physical response of the combustor for operating conditions that were not part of the training data.

Although not perfect, the models do an excellent job of predicting overall dynamics. They are particularly effective at capturing the phase and amplitude of the pressure signals, key elements for making accurate engine stability predictions.

"These reduced-order models are surrogates of the expensive high-fidelity model we rely upon now," Willcox said. "They provide answers good enough to guide engineers' design decisions, but in a fraction of the time."

How does it work? Deriving reduced-order models from training data is similar in spirit to conventional machine learning. However, there are some key differences. Understanding the physics affecting the stability of a rocket engine is crucial. And these physics must then be embedded into the reduced-order models during the training process.

"Off-the-shelf machine learning approaches will fall short for challenging problems in engineering and science such as this multiscale, multiphysics rocket engine combustion application," Willcox said. "The physics are just too complicated and the cost of generating training data is just too high. Scientific machine learning offers greater potential because it allows learning from data through the lens of a physics-based model. This is essential if we are to provide robust and reliable results."

April 16, 2020 - Nyon, Switzerland - The International Osteoporosis Foundation (IOF) Capture the Fracture® Working Group in collaboration with the Fragility Fracture Network Secondary Fragility Fracture Special Interest Group and National Osteoporosis Foundation has adapted existing metrics from the UK-based Fracture Liaison Service Database Audit to develop a patient-level Key Performance Indicator (KPI) set for Fracture Liaison Services (FLSs)1.

An FLS is a coordinated system of care that identifies, investigates, recommends treatment and monitors over time patients aged 50 and above presenting with a fragility fracture. FLS have demonstrated their potential clinical and cost effectiveness and have been recommended worldwide to reduce fracture risk after a first fracture. The IOF Capture the Fracture® Best Practice Framework (BPF) is a recognized guidance which is used to assess the organisational components of an FLS, and has been implemented in more than 400 FLS globally2. The new publication presents a complementary KPI set that measures the real-world secondary fracture prevention delivery at the patient level.

Associate Professor Kassim Javaid, co-chair of the Capture the Fracture® Programme stated: "The newly developed KPI set represents an important new tool for established FLS. It will help FLS examine their current performance and add service improvement cycles to their routine service provision, and it will permit further benchmarking against FLSs regionally, nationally and internationally."^

The eleven KPIs selected look at the proportion of patients with non-spinal fractures; with spine fractures (detected clinically and radiologically); assessed for fracture risk within 12 weeks of sentinel fracture; having DXA assessment within 12 weeks of sentinel fracture; having falls risk assessment; recommended anti-osteoporosis medication; commenced of strength and balance exercise intervention within 16 weeks of sentinel fracture; monitored within 16 weeks of sentinel fracture; started antiosteoporosis medication within 16 weeks of sentinel fracture; and prescribed anti-osteoporosis medication 52 weeks after sentinel fracture. The final KPI measures data completeness for each of the other KPIs. For these indicators, levels of achievement were set as 80% levels except for treatment recommendation where a level of 50% was used.

Professor Cyrus Cooper, president of IOF, added: "A first fragility fracture is a strong predictor of secondary fractures, which are associated with morbidity, excess mortality, and enormous socioeconomic costs. Yet despite a wide range of effective anti-osteoporosis medications and the increase in the world's aged populations, the proportion of patients receiving adequate secondary fracture prevention is alarmingly low."

"IOF urges health care systems worldwide to implement FLSs, as they have been shown to be the most effective way to tackle the burden of secondary fractures. The newly developed patient-level performance indicators, which complement the Capture the Fracture® Best Fracture Framework, will help established FLSs reach their full potential in the context of local challenges and opportunities, leading to improved patient care and outcomes."

While incentive-based programs have had many success stories in helping to regulate air quality, control pollution, and protect wildlife and fisheries, they may not be the answer to controlling invasive pests. In a new paper published in a top tier field journal, the Journal of Environmental Economics and Management, Erik Lichtenberg and Lars Olson, professors in Agricultural & Resource Economics at the University of Maryland (UMD), examined whether incentive-based tariff policies could be successful in preventing the introduction of invasive pests arriving in imported fruits and vegetables. Exotic organisms that have the potential to become invasive pests are found in about 3% of fresh fruits and vegetables, and under the Plant Protection Act, all cargo containing plant materials, from produce to cut flowers, requires inspection by the Animal and Plant Health Inspection Services of the United States Department of Agriculture (USDA-APHIS). While in other industries, incentive-based policies have helped make regulation more efficient and less costly overall, researchers find that to have measurable impacts on invasive pest reductions, these policies would not only damage diplomacy and trade relationships, but cost consumers roughly $38 million for each potential invasive pest introduction avoided.

"The goal of an incentive-based policy is to make somebody pay a price for things that they do that impose costs on society [such as pollution], or to subsidize a cost for creating benefits for society that would otherwise be expensive to bring to market [such as vaccination programs]," explains Lichtenberg. "Right now, every shipment into the United States that contains plant materials of some kind has to be inspected. If inspectors find something that might be an invasive pest, they have to act quickly, notify a scientist who can make an assessment, and turn it around within 24 hours because these are perishable commodities. But the idea here was that taxes could incentivize exporters to ensure that their cargoes were cleaner, which would reduce the burden of inspection or even the need for inspections completely."

To examine this concept, Lichtenberg and Olson developed a statistical model to simulate scenarios and determine the feasibility, possible effects, and overall cost to the consumer of an increased tariff on fruit and vegetable imports. They examined 10 years worth of data in their analysis including information on tariff rates and characteristics of fruit and vegetable shipments such as the type of commodity, country of origin, average commodity value, port of entry, growing season, and transportation pathway.

Researchers did in fact find that higher tariffs were related to a decreased likelihood of finding an invasive pest in a shipment, but this correlation was very small. "We are talking about increasing tariffs 4 to 13 times what they are now to get a measurable impact, and even then the impact is small," says Lichtenberg. "The changes aren't sensitive enough to really be a good tactic."

"But it gets worse," Lichtenberg adds, "because the majority of fruits and vegetables that come into this country come in without paying any tariff at all because of free trade agreements."

In the scenarios considered by the researchers, they found that revoking duty free status, or free trade agreements on fruits and vegetables, was the only way to get a measurable impact in pest reduction through tariffs. "Duty free products have a higher probability of having an invasive pest found than those entering with a higher tariff. The difference is small, but it is there," says Lichtenberg. "In the case of commodities that are duty free, the effects of adding a duty are pretty large. You end up with about a 25% reduction in invasive pests from rescinding duty free status."

Lichtenberg adds, "But then you ask, what does it cost us?"

The United States has free trade agreements with a host of countries, including Mexico, countries in Central America, the Caribbean, South America, Israel, and the Palestinian Territories. These free trade agreements not only keep the costs of fruits and vegetables down for the local consumer, but also are strategic diplomatic initiatives that better trade relations with our neighboring countries, incentivize the reduction of narcotic crops produced in South America, promote economic growth in Central America and the Caribbean, and help foster peace initiatives in the Middle East.

"If we are going to go down this road, we have to be prepared to throw away all these other diplomatic initiatives that we have," says Lichtenberg. "It makes our life and the world much messier and definitely isn't advisable."

Furthermore, there is a substantial cost to the consumer of "going down this road." Researchers looked at a group of 28 commodities accounting for a large share of the total quantity of shipments and calculated the consumer loss of rescinding duty free status compared to the reduction in potential invasive species, and found that the costs were about $38 million per introduction avoided.

"It's going to raise prices on things like fruits and vegetables and have impacts on consumers here in the United States," says Lichtenberg. "And we really want people eating more fruits and vegetables because they are good for us. So not only does it seem a bad idea from a diplomatic point of view, it also seems like a bad idea from our point of view as consumers who eat fruits and vegetables."

Overall, the cost of invasive species can be very high, with species like the Mediterranean fruit fly introduced in the 1980s costing California substantial resources to control and ensure that their entire citrus industry wasn't crippled, still with occasional sightings that cause additional eradication efforts. "Every so often one of these things gets out of hand and causes significant damage or requires a substantial investment in mitigation to prevent things from getting out of hand," says Lichtenberg. "New diseases and pests can be very costly to the industry and ultimately the consumer. But it's so rare, so when you look at probability and cost together, the expected damage is low."

Lichtenberg and Olson conclude, "There are a lot of places where incentive-based policies like an extra tax is a great idea, but this isn't one of them."

Lichtenberg and Olson will continue to examine issues surrounding invasive pests to determine the best strategies for control and management. "My motto is that if it's nasty and it has something to do with agriculture then I've probably studied it," says Lichtenberg.

Recently, research groups led by Prof. LIU Jian and Prof. WU Zhongshuai from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences have developed Fe1-xS-decorated mesoporous carbon spheres as the nanoreactor, which can be applied as lithium-sulfur battery cathode.

The nanoreactor showed excellent polysulfide catalytic activity and cyclic stability. The study was published in Advanced Energy Materials on Apr. 16.

Lithium-sulfur batteries have a high theoretical energy density of 2600 Wh kg-1 and theoretical capacity of 1675 mAh g-1. They are promising as a high-energy battery.

However, the slow conversion reaction dynamics of sulfur in the process of charging and discharging lead to low utilization rate of sulfur and serious shuttle effect. This further causes low capacity and stability of lithium-sulfur batteries.

Therefore, a reasonably designed electrocatalytic system is desired, so that catalytic transformation of polysulfide can be realized efficiently and steadily under high sulfur loading, resulting in high cyclic stability of lithium-sulfur battery.

In the current study, the researchers designed a mesoporous carbon nanoreactor decorated with highly dispersed Fe1-xS electrocatalyst nanoparticles (Fe1-xS-NC), and applied it as lithium-sulfur battery cathode for high catalytic activity and high sulfur loading.

The nanoreactor is featured with low mass density, high porosity, and highly dispersed electrocatalyst, which significantly improves the adsorption and catalytic conversion capacity of polysulfides. 

The researchers found that there was virtually no decay in capacity of Fe1-xS-NC from an initial value of 1070 mAh g-1 after 200 cycles and under a current density of 0.5 C.

"The nanoreactor design strategy provides a new protocol for building high-capacity and long-cycle rechargeable batteries," said Prof. LIU. "It will also open an avenue for design of safer and high-energy-density Li-metal batteries" Prof. WU added.

Recently, a group led by Prof. WU Heng'an and Prof. WANG Fengchao from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) in collaboration with Prof. Joel De Coninck from University of Mons provided a theoretical insight into capillary forces at the contact line and validated Young's equation based on a mechanical interpretation. The research results were published online in Physical Review Letters.

In 1805, the British scientist Thomas Young described the quantitative relationship between interfacial tension and contact angle when studying wetting and capillary phenomena. For more than 200 years, the Young's equation has become one of the most basic theories in the field of wetting. It describes the balance of three interface tensions parallel to the solid-liquid interface. However, researchers have disputed its interpretation as surface forces or surface energies and committed to prove its validity at the nanoscale.

Despite remarkable progress achieved in past years, puzzles and challenges still remain. First, the capillary force is not presented in the Young's equation. Additionally, the Young's equation cannot be verified directly in experiments. Compared with its thermodynamic derivation, there are more obstacles to put forward the mechanical interpretation of the equation.

To solve the problem, a theoretical model was proposed by the group from USTC to describe the capillary force at the contact line.

The researchers examined the capillary force balance on a liquid corner on the atomic scale and considered this problem with a liquid in coexistence with its vapor phase. The analysis was based on the decomposition of the solid-liquid and solid-vapor interface tensions into three terms, either of which has a clear physical meaning. The proposed model is verified by molecular dynamic simulations over a wide contact angle range. Differences in capillary forces are observed in evaporating droplets on homogeneous and decorated surfaces.

Following the same approach, they also verified Young's equation at the nanoscale from a view point of mechanical interpretation. Microscopic details regarding the mechanism of wetting and capillarity. These results provide new physical insight into the capillary force balance at the contact line.

This study not only provides new insights for the profound understanding of many phenomena of interface wetting, but also has important scientific significance in the application fields of micro-nano fluidic chip design and the improvement of low-permeability reservoirs recovery.

There remains a dearth of women in economics, with far fewer females securing tenure-track jobs and publishing academic research than men. Past research points to several barriers contributing to this "leaky pipeline" including: access to mentoring, social networks, and implicit biases.

Many groups, including the American Economic Association (AEA), are working to change this through workshops and other endeavors. But do these efforts really have an impact?

Research from Princeton University shows that an annual AEA workshop for female economists was effective in retaining women in academia and helping them to achieve tenure in the top 30 to 50 ranked schools in the country. These females also published more academic papers.

"It's remarkable that a two-day intervention could have such an effect," the researchers wrote in the study, which was published by the National Bureau of Economic Research (NBER).

The authors of the study included Janet M. Currie, Henry Putnam Professor of Economics and Public Affairs at Princeton University and the co-director of Princeton's Center for Health and Wellbeing. Currie's co-authors included Donna Ginther of the University of Kansas, Francine Blau of Cornell University, and Rachel Croson of Michigan State University.

The researchers designed and evaluated the experimental two-day CeMENT workshop (now the Workshop for Faculty in Doctoral Programs) under the auspices of the AEA's Committee on the Status of Women in the Economics Profession (CSWEP). The program is aimed at mentoring female faculty in tenure-track positions at Ph.D. granting economics departments in the U.S. or at institutions with similar research expectations.

In the national CeMENT workshops, senior female economists volunteer their time in order to transmit knowledge about what it takes to be successful. The workshops also help junior women to build peer networks of junior faculty who are working in similar research areas. Each workshop lasted two days, and was held in conjunction with the AEA annual meetings.

For the purposes of this study, the co-authors looked at the difference between a "treatment" group -- where women participated in the workshop -- and a "control group" in which the women did not. The two groups were randomly assigned from the pool of applicants. They mapped these groups to tenure status and academic employment, as well as to publications and grants. The dataset they obtained covered six cohorts of program participants. These individuals were observed four to 14 years after attending a workshop.

The workshops were especially helpful in building ongoing and lasting professional relationships, the researchers found. Many women who participated in the program kept in touch with the contacts they made at the workshops for years afterwards, using each other for support and advice. This helped them in terms of job placements and academic publishing.

"Our results speak to the importance of having mentors and peer networks, and suggest that women in economics often face difficulties in developing these relationships. We hope these results will inspire others to step forward with additional ways of tackling this persistent problem," the researchers wrote.

Saliva could be used instead of blood to monitor diabetes in a method proposed in research involving the University of Strathclyde.

The test has been developed as an alternative to the current prevalent practice of monitoring
blood glucose, which can be invasive, painful and costly.

Lab tests of the saliva process had an accuracy rate of 95.2%. The research shows promising results for monitoring diabetes, which affects an estimated 425 million people worldwide - around half of them undiagnosed.

The research has been published in the journal PLOS ONE. It also involved partners at the Federal University of Uberlandia in Minas Gerais, Brazil, the University of Vale do Paraíba in Sao Paolo, Brazil and the University of Saskatchewan in Canada.

Dr Matthew Baker, a Reader in Strathclyde's Department of Pure and Applied Chemistry and lead researcher in the project, said: "Frequent monitoring of diabetes is essential for improved glucose control and to delay clinical complications related to the condition. Early screening is also paramount in reducing these complications worldwide.

"Blood analysis for screening, monitoring and diagnosing diabetes is widely practised but is quite invasive and painful. The constant need of piercing the fingers several times daily for most patients may lead to the development of finger calluses, as well as difficulty in obtaining blood samples; furthermore, not everyone would want to give blood and there are circumstances in which it could be dangerous.

"Saliva reflects several physiological functions of the body, such as emotional, hormonal, nutritional and metabolic, and so its biomarkers could be an alternative to blood for robust early detection and monitoring. It is easy to collect, non-invasive, convenient to store and requires less handling than blood during clinical procedures, while also being environmentally efficient. It also contains analytes with real-time monitoring value which can be used to check a person's condition."

Dr Robinson Sabino-Silva, an associate professor at Federal University of Uberlandia (UFU) and a partner in the research, said: "The present protocol used in the infrared platform is able to detect spectral biomarkers without reagents. The combination of a non-invasive salivary collection and a reagent-free analysis permit us to monitor diabetes with a sustainable platform classified as green technology."

The lab tests used a scientific system known as Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. This has been used in the diagnosis of several diseases, although its applications in the monitoring of diabetic treatment have begun to emerge only recently. Samples were assessed in three categories - diabetic, non-diabetic and insulin-treated diabetic - and two potential diagnostic biomarkers were identified.

The researchers are hopeful that the process they have developed could be used for both Type 1 and Type 2 diabetes, although further study will be required to confirm this.

CLEMSON, South Carolina - Unless it happens to be allergy season, most people don't give a lot of thought to pollen. But new research might change the way we look at a field of flowers.

A collaborative study by Clemson scientist Matthew Koski suggests that pollen color can evolve independently from flower traits, and that plant species maintain both light and dark pollen because each offers distinct survival advantages.

Koski's research is featured as the cover story of the April issue of the Journal of Evolutionary Biology and is titled "Pollen colour morphs take different paths to fitness." Andrea Berardi of the University of Bern in Switzerland and Laura Galloway of the University of Virginia were Koski's co-authors.

"Plant biologists and evolutionary biologists and ecologists have long been fascinated with understanding the generation and maintenance of phenotypic diversity - why two individuals of the same species have differences in colorization or body type or height," said Koski, an assistant professor in the College of Science's department of biological sciences. "We assume that natural selection should reduce the amount of phenotype variation - that there should be one morph that survives the best and dominates the population. But that's not the case. With flowering plants, for example, when you go out in the field or even in a garden, you can see a huge amount of variation in the colors of petals on flowers. Evolutionary biologists have used flowering plants as models to understand how such a huge amount of variation persists in natural populations."

The focus is usually on petal variation, but pollen has its own intriguing differences and effects.

"When we look a little closer, there is actually a huge amount of variation in pollen in terms of coloration," Koski said. "Beekeepers have been looking at pollen color a lot longer than evolutionary biologists."

Beekeepers match the pollen that bees collect with color charts to figure out from which species of flowers bees are collecting pollen and nectar - an important thing to know since this can affect the quality and taste of honey.

Koski and his colleagues focused on the American bellflower (Campanula Americana), a tall plant that is coated with purple blooms in the summer. A closer look reveals something remarkable: Plants of this species can have marked differences in pollen color, ranging from white to deep purple. Koski worked with American bellflower plants at 24 sites from Alabama to Minnesota, first looking for geographic patterns in pollen color differences. Plants from eastern locations were found to have lighter purple pollen, while those from western locations favored darker purple.

"We tried to figure out what might be doing this," Koski said. "There could be some environmental factor driving darker pollen in the west and lighter pollen in the east. What we actually found is that western populations where pollen is darker experience much warmer summer temperatures. They get extreme high-heat events."

And it turns out that dark purple pollen varieties have higher viability under heat stress.

"If dark purple morphs have an advantage, why are lighter morphs persisting in nature?" Koski wondered.

That led him to look next at how pollinators perceive pollen color.

"We were expecting the lighter color to get more pollinator visits," Koski said. "What we found is that the dark color was receiving more pollinator visits from a really common pollinator called Megachile campanulae. It seemed like dark pollen plants had higher viability under heat stress and were also getting more pollinator visits. It's like two strikes against having light pollen."

In this most recent study, the team turned its focus to whether there was any trait correlation between lighter pollen and fitness.

"The main findings were that the lighter pollen morphs make a lot more flowers than the dark pollen morphs," Koski said. "Then, when I crossed them, they actually make a lot more seed as well. It suggested that the lighter pollen individuals have a higher seed-production ability. The pollen in the darker pollen individuals was larger and it made more anthocyanidins. These are traditionally seen as antioxidant compounds. In plants, they work the same as they do in our body, in that they are antioxidant compounds that can relieve abiotic stress."

This suggests that the increased anthocyanidin production in darker pollen might play a role in relieving heat stress.

"The big picture from this study and others is that light pollen morphs might actually be maintained because they have a higher seed production advantage by making more flowers and more seeds per flower or fruit," Koski said. "But the dark pollen flowers seem to have this paternal advantage in that their pollen is of a higher quality. This is related to a theory about how different phenotypes are maintained. Different phenotypes can achieve fitness through different means. This is a classic example of how this might be happening, and how across populations, we might have different agents of selection that are driving populations to be more darkly or lightly pigmented."

While animals can simply move to a cooler spot when it gets too hot, plants deal with heat stress through different means, such as pigmentation. This might indicate how plants adjust to a changing climate and might also influence selective breeding for that purpose.

This research could impact threatened pollinators as well. The common native bee (Megachile campanulae) collects pollen to feed itself and its young. The chemistry of that pollen might be a critical component in pollinator health, though this has not been thoroughly studied yet.

"There is also some suggestion from other work that pollinators can detect when pollen viability is low and then choose other flowers because the viability might affect the nutrient availability for pollinators," Koski said.

In essence, pollinators might be choosing flowers that are healthier for them. There are other theories to be explored, including whether white pollen flowers avoid pollen theft (having their pollen collected by inefficient pollinators) and whether darker pollen flowers, which are more likely to self-fertilize, are an advantage in an environment where pollinators are rare. This could be vitally important given the decline in bee populations.

One of Koski's next ventures will be to assist Jennifer Ison at the College of Wooster, whose research involving 3D printed flowers will help Wooster and others look at how pollinators see pollen color against the background of petals.