Tech

A simple and noninvasive treatment could become a prime post-crystallization process to optimize the optoelectronic properties of hybrid perovskite solar cell materials.

In this treatment devised by KAUST, bromine vapors penetrate the surface of as-synthesized perovskite crystals to reach their deep-lying layers, removing surface and bulk defects generated during crystal growth.

Lead-containing hybrid perovskites, such as methylammonium lead tribromide (MAPbBr3), present unique charge transport properties and easy processability in solution. These make them attractive as potential low-cost alternatives to traditional silicon-based light-harvesting solar cell materials. However, approaches that use solution processing to crystalize them tend to leave contaminants, such as oxygen and amorphous carbon. These approaches also produce halide vacancies that create lead cations, which can trap electrons to form metallic lead and restrict charge transport.

Various chemical treatments can reduce these defects, but most tinker with the composition of the precursor solution to optimize thin film and crystal formation. However, the researchers from the KAUST Solar Center sought something simpler.

"We were interested in developing a facile recipe that could be applied once crystal formation was complete," says Ahmad Kirmani, now a postdoc at the National Renewable Energy Laboratory, U.S., who conducted the study under the supervision of Aram Amassian and Omar Mohammed.

Co-author Ahmed Mansour, now a postdoc at Helmholtz-Zentrum Berlin, Germany, describes how the researchers chose a bromine vapor treatment because they had previously observed the improved conductivity of graphene when exposed to bromine. "Bromine is a volatile liquid at room temperature and readily evaporates without the need for any external source of energy," Mansour says.

The researchers suspended MAPbBr3 crystals in a bromine-vapor-saturated environment and monitored the effects of bromine exposure on material properties.

They were pleasantly surprised to find that bromine vapors suppressed metallic lead on the surface as well as in the bulk of the crystals, Mohammed says. "This meant that we could access the bulk properties of these crystals, such as their electrical conductivity," he adds. Prolonged bromine exposure produced a dramatic 10,000-fold enhancement in bulk electrical conductivity and a 50-fold increase in carrier mobility. Further assessment revealed that perovskite crystallization leaves behind voids and imperfections, which allows bromine to diffuse and permeate through the crystals.

Each of the former team members is currently exploring more applications for their treatment, such as for improving the power conversion efficiency of solar cells containing perovskite thin films as absorbers or for single-crystal devices--such as transistors, photodetectors and radiation detectors--that require excellent carrier mobility and intrinsic optoelectronic properties.

It is a very special kind of light, which can be used for important measurements: so-called frequency combs play a major role in laser research today. While the light of an ordinary laser only has one single, well-defined wavelength, a frequency comb consists of different light frequencies, which are precisely arranged at regular distances, much like the teeth of a comb.

Such frequency combs are difficult to generate. However, an international research team from Austria (TU Wien, Vienna), the USA (Harvard, Yale) and Italy (Milan, Turin) has now succeeded in producing this special kind of light, using simple circular quantum cascade lasers - a result that seemed to contradict conventional laser theories completely. As it turned out, turbulences, as they are known from aerodynamics or water waves, are responsible for this particularly ordered type of light. These results have now been published in the scientific journal "Nature".

Better than Physics Permits?

"Actually, we were first looking for something very different in our experiments," says Benedikt Schwarz, who researches frequency combs at TU Wien (Vienna) and Harvard University, and was awarded an ERC Starting Grant for his research in 2019. "We were investigating circular quantum cascade lasers, which is a special type of laser that has been manufactured in our laboratories at the Institute of Solid State Electronics for years. We wanted to investigate how certain defects affect the laser light." But much to the scientists' surprise, they found out that these circular mini-lasers can be used in a very simple way to produce frequency combs, which are composed of several light frequencies, arranged at equal distances.

"This is great for us, because this is exactly the kind of light we are looking for. Only we didn't expect to find it in this particular experiment - the success seemed to contradict current laser theory," explains Schwarz.

If the light from a laser is to consist of different frequencies at the same time, then the light cannot be constant - it must vary in time. An oscillation is required, repeating itself in a regular pattern. Only then, a frequency comb is created.

Turbulence can Cause Chaos - or Order

"When we thought about how this oscillation could be explained, we looked for similar phenomena in other scientific fields. Eventually we came across turbulence as the driving force that causes the oscillation leading to our frequency combs," says Benedikt Schwarz. Turbulence is a phenomenon that arises in many very different areas: In the smoke that emerges from an extinguished candle, turbulence can be seen that leads to chaotic, unpredictable patterns. But so-called wave instabilities can be found in all types of waves. A small disturbance gets bigger and bigger and eventually dominates the dynamics of the system.

The mathematical connection between such turbulence effects and the novel laser light could finally be found by a laser theory that Nikola Opačak from the Vienna University of Technology had recently published in November 2019: "We found that this laser theory can be connected to the same mathematical equation that also describes turbulence in other scientific disciplines," says Schwarz.

In a ring-shaped laser, wave instabilities can cause a stable frequency comb to form. In addition, there is a strong connection between different light frequencies - different frequencies are firmly coupled to each other.

The Comb as an Artificial Nose

Frequency combs play an important role in research mainly because they can be used to build tiny chemical sensors. Many molecules absorb light in the infrared range in a very characteristic way. By measuring which wavelengths are being absorbed, it is possible to determine which molecules are present. To do this, however, it is necessary to have as many different light frequencies in the infrared range available as possible - and this is exactly what an optical frequency comb provides in an ideal way.

In solid materials, when an electron changes position without another to fill its place, a positively charged 'hole' can appear which is attracted to the original electron. In more complex situations, the process can even result in stable clusters of multiple electrons and holes, whose behaviours all depend on each other. Strangely, the masses of each particle inside a cluster can be different to their masses when they are on their own. However, physicists aren't yet entirely clear how these mass variations can affect the overall properties of clusters in real solids. Through a study published in EPJ B, Alexei Frolov at the University of Western Ontario, Canada, reveals that the behaviour of one type of three-particle cluster displays a distinct relationship with the ratio between the masses of its particles.

Clusters of electrons and holes are already known to affect the absorption of light by semiconductors, which are now key components of many modern technologies. Frolov's research could significantly improve our understanding of these important materials, and it may also enable researchers to better explain smaller details in their optical and infrared spectra. In his study, Frolov considered a cluster containing two electrons with ordinary masses, and one hole which could vary between one and two electron masses. Through his calculations, distinctive behaviours emerged which displayed clear relationships with the ratio between the mass of this heavier hole, and that of each lighter electron.

Frolov based his calculations around the principles of quantum mechanics, which he used to derive a series of formulas to describe the mass dependence of three-particle clusters extremely accurately. He now hopes that these formulas could be modified to describe clusters containing four or more particles with varying masses. If achieved, this would create new opportunities to understand and fine-tune the properties of real semiconductors in future research.

CHAMPAIGN, Ill. -- Northern bobwhites are attracted to a habitat based on whether other bobwhites are present there, researchers at the University of Illinois at Urbana-Champaign report. This phenomenon, called conspecific attraction, could aid conservation efforts.

Bobwhites, Colinus virginianus, are resident birds - they decide where to live and stick to that decision for the rest of their lives, said Michael Ward, a professor of natural resources and environmental sciences who led the research.

"It's an important decision," he said. "It's like sampling food at different restaurants before you decide where to eat."

The researchers played recordings of bobwhite songs to see whether they could attract the birds to unoccupied sites in the Cold Springs area of Fort Polk, Louisiana.

"We played their calls on an MP3 player that was attached to a battery," Ward said. "We tried to mimic their natural singing behavior by playing the recordings more often in the morning and less in the afternoon."

The researchers studied the sites for three years. They did not play any recordings in the first year. The next year they divided the sites into those with and without recordings. The sites were flipped the third year.

"In the first year, we detected only one bird by listening for it," said Jinelle Sperry, a professor of natural resources and environmental sciences and co-author of the study. "Once we started playing the recordings in the treatment sites, the number of birds detected went up."

"The recordings brought in 12 to 15 birds," Ward said. "We expected more bobwhites but they might not be moving around as much, so it may take several years for their population to build up."

This method could help increase the number of bobwhites, whose populations have been declining for years because of habitat loss.

"Several areas have been restored for these birds," Sperry said. "However, restoring habitats is often not enough to get them to come in. This technique is cost effective and noninvasive compared with traditional methods, such as translocation of birds to restored areas."

The technique depends on the ability of the researchers to choose suitable habitat for the birds. "If you don't understand the life history or habitat needs, you may risk bringing them into a low-quality habitat where the birds don't do well," Sperry said.

The researchers hope to improve their conservation efforts.

"For this study, we took advantage of sites that had already been undergoing restoration," Sperry said. "In the future, we want to restore areas that are specific for these birds and use this tool to bring the birds in."

The researchers report their findings in the Journal of Field Ornithology.

Innovation by ancient farmers to improve soil fertility continues to have an impact on the biodiversity of the Amazon, a major new study shows.

Early inhabitants fertilized the soil with charcoal from fire remains and food waste. Areas with this "dark earth" have a different set of species than the surrounding landscape, contributing to a more diverse ecosystem with a richer collection of plant species, researchers from the State University of Mato Grosso in Brazil and the University of Exeter have found.

The legacy of this land management thousands of years ago means there are thousands of these patches of dark earth dotted around the region, most around the size of a small field. This is the first study to measure the difference in vegetation in dark and non-dark earth areas in mature forests across a region spanning a thousand kilometers.

The team of ecologists and archaeologists studied abandoned areas along the main stem of the Amazon River near Tapajós and in the headwaters of the Xingu River Basin in southern Amazonia.

Lead author Dr Edmar Almeida de Oliveira said: "This is an area where dark earth lush forests grow, with colossal trees of different species from the surrounding forest, with more edible fruit trees, such as taperebá and jatobá."

The number of indigenous communities living in the Amazon collapsed following European colonization of the region, meaning many dark earth areas were abandoned.

The study, published in the journal Global Ecology and Biogeography, reveals for the first time the extent to which pre-Columbian Amerindians influenced the current structure and diversity of the Amazon forest of the areas they once farmed.

Researchers sampled around 4,000 trees in southern and eastern Amazonia. Areas with dark earth had a significantly higher pH and more nutrients that improved soil fertility. Pottery shards and other artefacts were also found in the rich dark soils.

Professor Ben Hur Marimon Junior, from the State University of Mato Grosso, said: "Pre-Columbian indigenous people, who fertilized the poor soils of the Amazon for at least 5,000 years, have left an impressive legacy, creating the dark earth, or Terras Pretas de Índio"

Professor José Iriarte, an archaeologist from the University of Exeter, said: "By creating dark earth early inhabitants of the Amazon were able to successfully cultivate the soil for thousands of years in an agroforestry system

"We think ancient communities used dark earth areas to grow crops to eat, and adjacent forests without dark earth for agroforestry."

Dr Ted Feldpausch, from the University of Exeter, who co-authored the study with Dr Luiz Aragão from the National Institute for Space Research (INPE) in Brazil, said: "After being abandoned for hundreds of years, we still find a fingerprint of the ancient land-use in the forests today as a legacy of the pre-Colombian Amazonian population estimated in millions of inhabitants.

"We are currently expanding this research across the whole Amazon Basin under a project funded by the UK Natural Environment Research Council (NERC) to evaluate whether historical fire also affected the forest areas distant from the anthropogenic dark earths".

Many areas with dark earth are currently cultivated by local and indigenous populations, who have had great success with their food crops. But most are still hidden in the native forest, contributing to increased tree size, carbon stock and regional biodiversity. For this reason, the lush forests of the "Terra Preta de Índio" and their biological and cultural wealth in the Amazon must be preserved as a legacy for future generations, the researchers have said. Areas with dark earth are under threat due to illegal deforestation and fire.

"Dark earth increases the richness of species, an important consideration for regional biodiversity conservation. These findings highlight the small?scale long?term legacy of pre?Columbian inhabitants on the soils and vegetation of Amazonia," said co-author Prof Beatriz Marimon, from the State University of Mato Grosso.

Parasitic worms could offer a new treatment hope for patients suffering from the autoimmune disease multiple sclerosis, according to experts from the University of Nottingham.

The findings of the research, published in the journal JAMA Neurology, show that infecting MS patients with a safe dose of the hookworm parasite Necator americanus induces immunoregulatory responses and boosts the number of cells which help keep the immune system under control.

The research was led by Cris Constantinescu, Professor of Neurology in the University's School of Clinical Sciences and a leading MS expert, and David Idris Pritchard, Professor of Parasite Immunology in the University's School of Pharmacy, who has spent decades studying the biology of the hookworm. The study was funded by the Multiple Sclerosis Society.

MS is a condition that can affect the brain and spinal cord, causing a wide range of potential symptoms, including problems with vision, arm or leg movement, sensation or balance. Whilst treatments are available, there is currently no cure.

The study aimed to show that the presence of hookworms in the body switches off the mechanism by which the body's immune system becomes overactive -- the main cause of MS -- reducing both the severity of symptoms and the number of relapses experienced by the patients.

71 patients were recruited for a controlled clinical trial who suffer from the most common type of the disease, relapsing remitting MS (RRMS).

Symptoms in patients such as vision problems, dizziness and fatigue, appear and then fade away either partially or completely, and secondary progressive MS with superimposed relapses.

Half of the patients on the trial, received a low dose of the hookworms --25 of the microscopic larvae -- on a plaster applied to the arm, while the other half received a placebo plaster.

At the beginning of the trial, the participants underwent an MRI scan to record the scarring or lesions on the brain which are present in MS patients. Over the course of nine months, all the patients were scanned on a regular basis for new or worsening lesions which can be a tell-tale sign of relapse.

The results at the end of the trial showed that the total number of new MRI lesions did not differ significantly between patients receiving hookworm and those receiving placebo. However, more than half the patients on hookworm had no new lesions at all.

In addition, the scientists found an increase in the percentage of regulatory T cells found within patients who received the hookworm. These cells help to keep the immune system under control, and are deficient in MS patients. The results showed that the hookworm increases this type of cell which could be beneficial in the treatment of MS.

Professor Constantinescu said: "The findings of our study are encouraging. Whilst the results are modest in comparison to the current very potent and highly effective treatments available, some patients with milder disease or more inclined for natural treatments may consider this as an option.

"On the more biological level, it is worth harnessing immunoregulatory mechanisms, for example increasing regulatory T cells in MS (and possibly other autoimmune diseases). Further studies are now needed to establish whether different protocols can enhance this benefit. For instance, would a booster infection in around nine months enhance the regulatory T cells responses and enhance the clinical/radiological benefit?"

Professor Pritchard is equally encouraged by the results of the trial. He said: "In essence, we were able to safely and easily deliver a living drug to humans, an organism which has long lasting modulatory effects on the immune system, given the time the adult parasite is resident in the small intestine (years). Clearly, this study has set the scene for follow up trials, where I would envisage booster infections being given to enhance the immune modulation already recorded. The dosage used in the current study (25 larvae) was the maximum permitted under regulatory guidelines, therefore boosting with this dose would be preferable to increasing the level of primary exposure."

A full copy of the study can be found here.

A Rutgers-led study finds that online misinformation, or "fake news," lowers people's trust in mainstream media across party lines. The researchers defined fake news as fabricated information that looks like news content but lacks the editorial standards and practices of legitimate journalism.

In contrast to the negative relationship between fake news exposure and trust in media, the study, published in Misinformation Review, found consuming fake news increased political trust, especially trust in Congress and the justice system. Fake news consumption was associated with a 4% increase in overall political trust and an 8% increase for trust in Congress.

While the overall association between fake news exposure and political trust was positive, there are differences among political parties, researchers say. Strong liberals trusted the government less after consuming fake news, while moderates and conservatives trusted it more.

"Strong liberals exposed to right-leaning misinformation may be most likely to reject its claims and mistrust the current Republican government," said lead author Katherine Ognyanova, an assistant professor of communication at Rutgers University-New Brunswick's School of Communication and Information. "In contrast, moderate or conservative respondents may take that misinformation at face value and increase their confidence in the current political institutions."

Attitudes towards the media and the federal government affect how people find and evaluate information, who they believe and how they act during exigent circumstances, and how they participate in the political process.

Researchers say the findings emphasize the critical importance of technological, social and regulatory efforts to curb the spread of fake news.

"It has become clear that none of the stakeholders -- audience members, technological companies, media, fact-checking organizations, or regulators -- can tackle this problem on their own," said Ognyanova. "Platforms should work hand in hand with media and users to implement solutions that increase the social costs of spreading false stories. Regulators can help increase the transparency that is required in the process."

The researchers collected data from 3,000 Americans who participated in two survey waves in October and November of 2018, shortly before and after the U.S. midterm elections. The researchers also used new methodology that involved having people install a browser add-on that tracks what they read on the Web between the surveys. About 8% (227) of the respondents agreed to install the browser. The participants' browsing history was used to evaluate their exposure to fake news sources and assess whether consuming misinformation was linked to changes in trust.

"The time period we collected the digital data was characterized by considerable public attention to political news and events in the United States," said Ognyanova. "On Nov. 6, 2018, many states had their first major election since Donald Trump was voted into office. In the weeks following the election, both the public and the media were focused on the results and their implications for American political life. The increased attention to political events at that time would likely strengthen the effects of exposure to mainstream and fake news content."

June 18, 2020 -- Social distancing and limited access to contraceptive and abortion care during the COVID-19 pandemic is affecting the sexual and reproductive health of adolescents and young adults according to a new study by researchers at Columbia University Mailman School of Public Health and Rutgers University. The researchers address how these challenges, as well as peer and romantic relationships, are being navigated. The findings are published in the journal Perspectives on Sexual and Reproductive Health.

Huge changes for adolescents and young adults, include school closures, potentially much more time with family, the interruption of the normal trajectory toward increased independence and, for many, very limited or no physical proximity to sexual and romantic partners.

Even though the pandemic may lead to less opportunities for sex for some young people, disruptions in access to contraception and abortion can be extremely problematic for adolescents and young adults who are still able to be physically close to their partners during the pandemic, note the authors. "The good news is that some services, including obtaining many forms of contraception and receiving testing and treatment for sexually transmitted diseases can be handled through telemedicine," said Leslie Kantor, a professor and chair of the Rutgers Department of Urban Global Public Health. "If telemedicine remains as widely available as it has been during the coronavirus pandemic, access to sexual and reproductive health care may actually improve for young people." However, Kantor and colleagues say that lack of privacy and confidentiality, which many adolescents and young adults are experiencing while living at home with family, can also hinder the ability to get necessary sexual and reproductive healthcare.

In terms of testing for sexually transmitted infections or seeking abortion care, there is not a lot of data specifically on young people. But many states have tried to restrict abortion access by arguing it is not an essential service despite the fact that abortion clearly is essential and needs to be timely. There also have been very concerning declines in vaccinations for all children older than age 2 and the use of the HPV vaccine, which prevents cancer-causing infections and pre-cancers, has plummeted.

LGBTQ youth have also been impacted, although fortunately, many LGBTQ centers quickly moved support groups and other services online. Services such as QChat Space were already using digital platforms to convene and offer support to LGBTQ youth. However, for some youth whose families are less accepting, being quarantined for months can lead to significant tensions and confidentiality concerns, which could make LGBTQ youth more isolated.

While social disruption resulting from the pandemic affects young adults' sense of health and well-being, one positive aspect is that young adults are digital natives familiar with online platforms and social media. "Young people are supposed to be gaining independence at this time in life, so for those who have had to return home after a period of being away, maintaining relationships with friends and romantic partners at a distance may be particularly challenging. Our view that their constant digital connection was negative is now a positive for them at this time," said David Bell, MD, MPH, Columbia Mailman School of Public Health associate professor of Population and Family Health and Pediatrics.

ABERDEEN PROVING GROUND, Md. -- Soon, the U.S. Army will be able to deploy autonomous air vehicles that can change shape during flight, according to new research presented at the AIAA Aviation Forum and Exposition's virtual event June 16.

Researchers with the U.S. Army's Combat Capabilities Development Command's Army Research Laboratory and Texas A&M University published findings of a two-year study in fluid-structure interaction. Their research led to a tool, which will be able to rapidly optimize the structural configuration for Future Vertical Lift vehicles while properly accounting for the interaction between air and the structure.

Within the next year, this tool will be used to develop and rapidly optimize Future Vertical Lift vehicles capable of changing shape during flight, thereby optimizing performance of the vehicle through different phases of flight.

"Consider an [Intelligence, Surveillance and Reconnaissance] mission where the vehicle needs to get quickly to station, or dash, and then attempt to stay on station for as long as possible, or loiter," said Dr. Francis Phillips, an aerospace engineer at the laboratory. "During dash segments, short wings are desirable in order to go fast and be more maneuverable, but for loiter segments, long wings are desirable in order to enable low power, high endurance flight."

This tool will enable the structural optimization of a vehicle capable of such morphing while accounting for the deformation of the wings due to the fluid-structure interaction, he said.

One concern with morphing vehicles is striking a balance between sufficient bending stiffness and softness to enable to morphing," Phillips said. "If the wing bends too much, then the theoretical benefits of the morphing could be negated and also could lead to control issues and instabilities."

Fluid-structure interaction analyses typically require coupling between a fluid and a structural solver.

This, in turn, means that the computational cost for these analyses can be very high - in the range of about 10,000s core hours - for a single fluid and structural configuration.

To overcome these challenges, researchers developed a process that decouples the fluid and structural solvers, which can reduce the computational cost for a single run by as much as 80 percent, Phillips said.

The analysis of additional structural configurations can also be performed without re-analyzing the fluid due to this decoupled approach, which in turn generates additional computational cost savings, leading to multiple orders of magnitude reductions in computational cost when considering this method within an optimization framework.

Ultimately, this means the Army could design multi-functional Future Vertical Lift vehicles much more quickly than through the use of current techniques, he said.

For the past 20 years, there have been advances in research in morphing aerial vehicles but what makes the Army's studies different is its look at the fluid-structure interaction during vehicle design and structural optimization instead of designing a vehicle first and then seeing what the fluid-structure interaction behavior will be.

"This research will have a direct impact on the ability to generate vehicles for the future warfighter," Phillips said. "By reducing the computational cost for fluid-structure interaction analysis, structural optimization of future vertical lift vehicles can be accomplished in a much shorter time-frame."

According to Phillips, when implemented within an optimization framework and coupled with additive manufacturing, the future warfighter will be able to use this tool to manufacture optimized custom air vehicles for mission specific uses.

Phillips presented this work in a paper, Uncoupled Method for Massively Parallelizable 3-D Fluid-Structure Interaction Analysis and Design, co-authored by the laboratory's Drs. Todd Henry and John Hrynuk, as well as Texas A&M University's Trent White, William Scholten and Dr. Darren Hartl.

PROVIDENCE, R.I. [Brown University] -- A team of Brown University researchers has found a way to double the toughness of a ceramic material used to make solid-state lithium ion batteries. The strategy, described in the journal Matter, could be useful in bringing solid-state batteries to the mass market.

"There's huge interest in replacing the liquid electrolytes in current batteries with ceramic materials because they're safer and can provide higher energy density," said Christos Athanasiou, a postdoctoral researcher in Brown's School of Engineering and lead author of the research. "So far, research on solid electrolytes has focused on optimizing their chemical properties. With this work, we're focusing on the mechanical properties, in the hope of making them safer and more practical for widespread use."

The electrolyte is the barrier between a battery's cathode and anode through which lithium ions flow during charging or discharging. Liquid electrolytes work pretty well -- they're found in most batteries in use today -- but they have some problems. At high currents, tiny filaments of lithium metal can form inside the electrolytes, which cause batteries to short circuit. And since liquid electrolytes are also highly flammable, those shorts can lead to fires.

Solid ceramic electrolytes aren't flammable, and there's evidence that they can prevent the formation of lithium filaments, which could enable batteries to operate at higher currents. However, ceramics are highly brittle materials that can fracture during the manufacturing process and during use.

For this new study, the researchers wanted to see if infusing a ceramic with graphene -- a super-strong carbon-based nanomaterial -- could increase the material's fracture toughness (a material's ability to withstand cracking without falling apart) while maintaining the electronic properties needed for electrolyte function.

Athanasiou worked with Brown engineering professors Brian Sheldon and Nitin Padture, who for years have used nanomaterials to toughen ceramics for use in the aerospace industry. For this work, the researchers made tiny platelets of graphene oxide, mixed them with powder of a ceramic called LATP, and then heated the mixture to form a ceramic-graphene composite.

Mechanical testing of the composite showed a more than two-fold increase in toughness compared to the ceramic alone. "What's happening is that when crack starts in a material, the graphene platelets essentially hold the broken surfaces together so that more energy is required for the crack to run," Athanasiou said.

Experiments also showed that the graphene didn't interfere with the electrical properties of the material. The key was making sure the right amount of graphene was added to the ceramic. Too little graphene wouldn't achieve the toughening effect. Too much would cause the material to become electrically conductive, which is not desired in an electrolyte.

"You want the electrolyte to conduct ions, not electricity," Padture said. "Graphene is a good electrical conductor, so people may think we're shooting ourselves in the foot by putting a conductor in our electrolyte. But if we keep the concentration low enough, we can keep the graphene from conducting, and we still get the structural benefit."

Taken together, the results suggest that nanocomposites could provide a path forward to making safer solid electrolytes with mechanical properties to be used in everyday applications. The group plans to continue working to improve the material, trying nanomaterials other than graphene and different types of ceramic electrolyte.

"To our knowledge, this is the toughest solid electrolyte that anyone has made to date," Sheldon said. "I think what we've shown is that there's a lot of promise in using these composites in battery applications."

HOUSTON -- In the first study to look at objective measures of sedentary behavior and cancer mortality, researchers from The University of Texas MD Anderson Cancer Center found that greater inactivity was independently associated with a higher risk of dying from cancer. The most sedentary individuals had an 82% higher risk of cancer mortality compared to the least sedentary individuals. An accelerometer was used to measure physical activity, rather than relying on participants to self-report their activity levels

"This is the first study that definitively shows a strong association between not moving and cancer death," said Susan Gilchrist, M.D., associate professor of Clinical Cancer Prevention and lead author of the study, published today in JAMA Oncology. "Our findings show that the amount of time a person spends sitting prior to a cancer diagnosis is predictive of time to cancer death."

Researchers also found that replacing 30 minutes of sedentary time with physical activity was associated with a 31% lower risk of cancer death for moderate-intensity activity, such as cycling, and an 8% lower risk of cancer death for light-intensity activity, such as walking.

"Conversations with my patients always begin with why they don't have time to exercise," said Gilchrist, who leads MD Anderson's Healthy Heart Program. "I tell them to consider standing up for 5 minutes every hour at work or taking the stairs instead of the elevator. It might not sound like a lot, but this study tells us even light activity has cancer survival benefits."

Study design

This study involved a cohort of participants from the nationally representative REGARDS study, which recruited more than 30,000 U.S. adults over the age of 45 between 2003 and 2007 to study long-term health outcomes.

To measure sedentary behavior, 8,002 REGARDS participants who did not have a cancer diagnosis at study enrollment wore an accelerometer on their hip during waking hours for seven consecutive days. The accelerometer data was gathered between 2009 and 2013. After a mean follow-up of 5 years, 268 participants died of cancer. Longer duration of sedentary behavior was independently associated with a greater risk of cancer death.

The study also found that engaging in either light or moderate to vigorous physical activity made a difference. Investigators assessed sedentary time, light-intensity physical activity (LIPA) and moderate to vigorous physical activity (MVPA) in the same model and found that LIPA and MVPA, not sedentary behavior, remained significantly associated with cancer mortality.

"From a practical perspective, this means that individuals who replaced either 10 to 30 minutes of sedentary time with either LIPA or MVPA had a lower risk of cancer mortality in the REGARDS cohort," Gilchrist said.

The study had several limitations, including a potentially healthier participant sample compared to the full REGARDS cohort and a lack of site-specific cancer data, including type of tumor and treatment.

"Our findings reinforce that it's important to 'sit less and move more' and that incorporating 30 minutes of movement into your daily life can help reduce your risk of death from cancer," Gilchrist said. "Our next step is to investigate how objectively measured sedentary behavior impacts site-specific cancer incidence and if gender and race play a role."

TORONTO, ON - JUNE 2020 - The results of new research published this week in Scientific Reports reveal insights that may have profound effects on the use of medicinal leeches in hospital-based medicine.

An international team of researchers, led by Royal Ontario Museum (ROM) scientist Sebastian Kvist, have announced the completion and results of their work to sequence the genome of Hirudo medicinalis, a European leech, and one of the most prominently used medicinal species.

The team focused on the diversity of blood thinners--or anticoagulants--contained within the genome, generating results that may have profound effects on how blood-sucking organisms are used in hospital settings.

Medicinal leeches have long been used to treat various human conditions. However, their use in pre-modern medicine was based on early, unfounded theories of healing--primarily, that human body function relied on the balance of the four "humors": blood, phlegm, black bile and yellow bile. Draining a patient's blood, often by applying live leeches, was thought to restore that balance.

Today, two leech species--Hirudo verbana and Hirudo medicinalis--are used for healing practices based soundly in science, primarily for the replantation of digits (e.g. fingers) or skin grafting surgery. Their saliva contains the strongest blood thinners known to medicine and can relieve the buildup of blood after surgery and promote the healing of blood vessels. However, the full complement of compounds in medicinal leech saliva that achieve this outcome was not known until now.

"Incredibly, the leech uses 15 different proteins known to negatively affect the blood-clotting mechanism in vertebrates, and 17 other proteins that are likely also part of the same anti-clotting process," says Kvist, an evolutionary biologist and Curator of Invertebrate Zoology at the ROM. Kvist is also a cross-appointed professor at the University of Toronto and the lead curator of the award-winning ROM original exhibition Bloodsuckers: Legends to Leeches.

"This is far more than we anticipated, and the insights generated by this research will allow medical professionals to better understand how and when to use leeches in their practice," he adds.

As only the third leech genome ever sequenced, Hirudo medicinalis provides important comparative data for understanding the evolution of bloodfeeding in leeches, notes the paper's senior author, Mark Siddall, Curator of Annelida and Protozoa at the American Museum of Natural History in New York City.

"It is astonishing that the most utilized, well-known and famous leech species in the world had not been investigated at this level," says Siddall. "This research provides critical insight into the evolution of bloodfeeding in leeches and will play an important role in future research."

Durham, NC - Millions of sufferers of glaucoma might someday benefit from a study released today in STEM CELLS in which a "disease in a dish" stem cell model was used to examine the mechanism in glaucoma that causes retinal ganglion cells (RGCs) to degenerate, resulting in loss of vision. The knowledge the study provides could result in new therapeutic approaches for this leading cause of blindness worldwide.

RGCs are a group of nerve cells located in the retina that send images to the brain and enable you to see. Glaucoma attacks these cells and, once they die, they are not replaced. However, why and how glaucoma causes the RGCs to degenerate is something of a mystery.

Stem cell modeling of the disease may shed light on this. Over the past decade, significant progress has been made using induced pluripotent stem cell (iPSC) technology to mimic glaucoma. This includes the generation of human RGCs from iPSCs, which led to the development of a disease model for primary open angle glaucoma (POAG) -- the most common form of glaucoma -- as well as an optic nerve model that demonstrated the supportive role of mTOR signaling in the regeneration of hRGC axons following chemical axotomy.

"However, both these models can be improved by characterizing the developmental trajectories of control and disease-specific RGCs," said Iqbal Ahmad, Ph.D., of the University of Nebraska Medical Center. He and his UNMC colleagues, Pooja Teotia, Ph.D., and Meng Niu, Ph.D., conducted the study reported on in STEM CELLS.

Dr. Ahmad continued, "This characterization includes the generation of hRGCs through normal developmental time and stages containing a complement of different subtypes, against which the developmental aspects of RGC abnormality in a disease model can be evaluated. Information about different RGC subtypes is not only important from a functional viewpoint, but also for understanding the underlying mechanism of glaucomatous degeneration, given the emerging evidence that the susceptibility and resistance of RGCs are subtype dependent."

In developing their model, the researchers used a single cell transcriptome analysis of human RGCs generated from normal (controls) and SIX6 risk allele iPS cells. (Previous studies have identified a significant association between POAG and SIX6, a gene that plays a role in ocular development.)

They observed that the developmental trajectories, beginning from neural stem cells to RGCs, were similar between SIX6 risk allele and control RGCs.

"However," Dr. Ahmad said, "we observed that the differentiation of SIX6 risk allele RGCs was stalled at the retinal progenitor cell stage, keeping them immature and deficient in subtype composition, compared to the controls. This was likely due to dysregulated mTOR and Notch signaling pathways that play an important role in RGC development. Furthermore," he added, "SIX6 risk allele RGCs, as compared to controls, expressed fewer genes corresponding to RGC subtypes that are preferentially resistant to degeneration.

"The immature phenotype of SIX6 risk allele RGCs with under-represented degeneration-resistant subtypes, may make them vulnerable to glaucomatous degeneration," he concluded.

"This study demonstrates the power of single cell sequencing methods for providing new insights into POAG pathology at the cellular and molecular level, which is necessary for formulation of new therapeutic approaches", said Dr. Jan Nolta, Editor-in-Chief of STEM CELLS. "This is truly remarkable and something that we could have not imagined was feasible thirteen years ago until the concept of patient specific iPSC disease modelling was invented. This is an excellent step forward and a phenomenon we will see becoming a daily reality in disease phenotyping and drug discovery."

For scientists, engaging in commercial activities such as patenting and starting new ventures can be much more lucrative than relying on pure academic work. However, according to new research by Henry Sauermann of ESMT Berlin and colleagues Wesley M. Cohen (Duke University) and Paula Stephan (Georgia State University), money is not the main reason why scientists choose to work on commercial activities. Other motives such as social impact and intellectual challenge appear to be more important. The study, titled "Not in the job description: The commercial activities of academic scientists and engineers," has been published in Management Science.

Using panel data of over 2,000 academics employed at US institutions, the authors investigated how scientists' commercial activities - measured by the number of patents they created - are related to their motives. Specifically, they examined the role of desires for peer recognition, money, intellectual challenge, and social impact. Surprisingly, the data show that there is virtually no association between an interest in money and academics' patent applications.

"Our findings suggest that an emphasis on the revenue that patents can potentially generate does little to incentivize commercial activities by scientists and engineers," says Sauermann, who is a professor of strategy at ESMT. "Instead, other motives play an important role, although these motives also differ across scientific fields."

In the life sciences - such as biology and environmental sciences - the desire for social impact is a particularly strong driver. Academics with a one standard deviation higher motive to contribute to society had an almost 60 percent higher patent count. Among engineers, the motives tied to patenting are intellectual challenge and peer recognition. A one standard deviation higher score on the two motives was associated with a 68 and 36 percent higher patent output, respectively.

By way of contrast, physical scientists - such as physicists, chemists, and mathematicians - who put a high value on peer recognition were found to be less likely to patent. "This indicates that commercial engagement in the physical sciences - but not other fields - may 'blemish' academic careers," says Sauermann.

More generally, Sauermann argues, "Policy makers and technology transfer offices need to recognize that academics' motives differ across fields, and structure their support mechanisms and policies accordingly. Most importantly, instead of hyping the amount of revenue earned from patents, they should stress other motives, such as social impact arising from commercial work."

An international collaboration bringing together over 200 scientists from 13 countries has shown that the very high-energy gamma-ray emission from quasars, galaxies with a highly energetic nucleus, is not concentrated in the region close to their central black hole but in fact extends over several thousand light-years along jets of plasma. This discovery shakes up current scenarios for the behaviour of such plasma jets. The work, published in the journal Nature on June 18th, 2020, was carried out as part of the H.E.S.S collaboration, involving in particular the CNRS and CEA in France, and the Max Planck society and a group of research institutions and universities in Germany.

Over the past few years, scientists have observed the Universe using gamma rays, which are very high-energy photons. Gamma rays, which form part of the cosmic rays that constantly bombard the Earth, originate from regions of the Universe where particles are accelerated to huge energies unattainable in human-built accelerators. Gamma rays are emitted by a wide range of cosmic objects, such as quasars, which are active galaxies with a highly energetic nucleus. The intensity of the radiation emitted from these systems can vary over very short timescales of up to one minute. Scientists therefore believed that the source of this radiation was very small and located in the vicinity of a supermassive black hole, which can have a mass several billion times that of the Sun's. The black hole is thought to gobble up the matter spiralling down into it and eject a small part of it in the form of large jets of plasma, at relativistic speeds, close to the speed of light, thus contributing to the redistribution of matter throughout the Universe.

Using the H.E.S.S. (1) observatory in Namibia, an international astrophysics collaboration observed a radio galaxy (a galaxy that is highly luminous when observed at radio wavelengths) for over 200 hours at unparalleled resolution. As the nearest radio galaxy to Earth, Centaurus A is favourable to scientists for such a study, enabling them to identify the region emitting the very high-energy radiation while studying the trajectory of the plasma jets. They were able to show that the gamma-ray source extends over a distance of several thousand light-years. This extended emission indicates that particle acceleration does not take place solely in the vicinity of the black hole but also along the entire length of the plasma jets. Based on these new results, it is now believed that the particles are reaccelerated by stochastic processes along the jet. The discovery suggests that many radio galaxies with extended jets accelerate electrons to extreme energies and might emit gamma-rays, possibly explaining the origins of a substantial fraction of the diffuse extragalactic gamma background radiation.

These findings provide important new insights into cosmic gamma-ray emitters, and in particular about the role of radio galaxies as highly efficient relativistic electron accelerators. Due to their large number, it would appear that radio galaxies collectively make a highly significant contribution to the redistribution of energy in the intergalactic medium. The results of this study required extensive observations and optimized analysis techniques with H.E.S.S., the most sensitive gamma-ray observatory to date. Next-generation telescopes (Cherenkov Telescope Array, or CTA) will no doubt make it possible to observe this phenomenon in even greater detail.