Culture

WASHINGTON, June 9, 2021 -- The World Health Organization and the Centers for Disease Control recommend keeping a certain distance between people to prevent the spread of COVID-19. These social distancing recommendations are estimated from a variety of studies, but further research about the precise mechanism of virus transport from one person to another is still needed.

In Physics of Fluids, by AIP Publishing, researchers from Stony Brook University, Harvard, ETH Zurich, and Hanyang University demonstrate normal breathing indoors without a mask can transport saliva droplets capable of carrying virus particles to a distance of 2.2 meters, or 7.2 feet, in a matter of 90 seconds.

The use of a face mask significantly reduces the distance these droplets travel. After almost two minutes, the saliva droplets restricted by a mask had traveled only 0.72 meters, under 2.4 feet and well below the distance of 1.8 meters, or 6 feet, suggested by the CDC.

The study used computer simulations with a more realistic model for the situation of interest than those used in previous studies. Previous work considered aerosol transport after coughing or sneezing, while this study specifically looked at normal human breathing. A normal breath produces periodic jet flows that contain saliva droplets, but the velocity at which the jet travels is less than a tenth that of a cough or sneeze.

The investigators found even normal breathing produces a complex field of vortices that can move saliva droplets away from the person's mouth. The role of these vortices has not previously been understood.

"Our results show that normal breathing without a facial mask generates periodic trailing jets and leading circular vortex rings that propagate forward and interact with the vortical flow structures produced in prior breathing cycles," said author Ali Khosronejad.

This complex vorticity field can transport aerosol droplets over long distances. A face mask dissipates the kinetic energy of the jet produced by an exhaled breath, disrupting the vortices and limiting the movement of virus-laden droplets.

The investigators considered the effect of evaporation of the saliva droplets. In the case of no mask, they found the saliva droplets near the front of the plume of exhaled breath had partially evaporated, reaching a size of only one-tenth of a micron. In stagnant indoor air, droplets this size would not settle to the ground for days.

The use of a mask partially redirects the exhaled breath downward and significantly restricts forward movement of the plume, so the risk of suspended droplets remaining in the air is substantially reduced.

"To simplify the breathing process, we did not consider the flow of air-saliva mixture through the nose and solely accounted for the flow through the mouth," Khosronejad said. "In future studies, we will explore the effect of normal breathing via both the nose and mouth."

GRAND RAPIDS, Mich. (JUNE 8, 2021) -- Chronic inflammation in the gut may propel processes in the body that give rise to Parkinson's disease, according to a study by scientists at Van Andel Institute and Roche.

The study, published in Free Neuropathology, is the latest in a growing list that links the gut and the immune system to Parkinson's. The researchers' findings in an experimental mouse model of gut inflammation track with several large-scale epidemiological studies that show an association between Parkinson's and inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease.

Epidemiological evidence from other groups indicates the risk of developing Parkinson's fades in certain people whose inflammatory bowel disease is treated with anti-TNF, a standard-of-care anti-inflammatory therapy, which suggests that reducing gut inflammation may have promise for mitigating Parkinson's onset.

"There is increasing evidence that changes in the gut can affect a variety of neurological and psychiatric brain disorders," said Patrik Brundin, M.D., Ph.D., VAI deputy chief scientific officer and co-corresponding author of the study. "Parkinson's is a complex disease with a wide range of factors that work in concert to spark its onset and progression. We need to understand the gut's likely influence on Parkinson's development better. This study provides novel insights, and this new knowledge can facilitate the development of improved treatment approaches."

In their disease models, the team found that chronic gut inflammation triggers a protein called alpha-synuclein to clump together in walls of the colon, as well as in local immune cells called macrophages. A similar process may play out in the colons of some people -- such as those with inflammatory bowel diseases -- thereby increasing their risk to develop Parkinson's as shown in studies by other groups.

Similarly, in the brains of people with Parkinson's, "sticky" alpha-synuclein aggregates also develop. For reasons that still are unclear, these aggregates can clog the molecular machinery that keep neurons alive. The resulting loss of some of these critical cells -- and the chemical messenger they produce called dopamine -- causes Parkinson's hallmark movement-related symptoms, such as freezing and loss of voluntary movement. The additional wide-spread development of alpha-synuclein aggregates throughout the brain also may be associated with the disease's non-motor symptoms and may fuel its progression, which cannot be slowed or stopped with existing treatments.

The study also revealed that chronic inflammation in the gut early in life can exacerbate alpha-synuclein clumping throughout the brain in older mice. While it isn't clear exactly how this happens, the team has two theories: first, they suggest inflammatory chemicals may travel from the gut to the brain via the bloodstream, triggering a runaway inflammatory immune response that leads to protein aggregation. Another idea is that alpha-synuclein aggregates may travel to the brain via the vagus nerve, one of the longest nerves in the body and a "superhighway" between the gut and the brain. Once there, the proteins may then execute their toxic activity in the brain.

"We now know that systems throughout the body contribute to Parkinson's," said Emmanuel Quansah, Ph.D., a postdoctoral fellow in Brundin's lab and a key contributor and co-author of the study. "It was striking to see protein aggregation pathology in the brain that mirrored pathology in the colon brought on by inflammation. A particularly intriguing observation was the loss dopamine-producing nerve cells -- which play a major role in Parkinson's onset -- in our models that had gut inflammation a year-and-a-half earlier."

Notably, the team also found that modulating immune activation in the colitis mouse model by genetic or therapeutic means tuned the level of alpha-synuclein clumps in the colon up or down.

"Our results in mice, together with the genetic and epidemiological data by others in humans, make a strong case for further exploring systemic immune pathways for future therapies and biomarkers for Parkinson's," said Markus Britschgi, Ph.D., Senior Principal Scientist and Section Head in the Neuroscience and Rare Diseases Research Department at the Roche Innovation Center Basel and co-corresponding author of the study.

Authors include first author Stefan Grathwohl, Ph.D. (previously a Roche postdoctoral fellow), Nazia Maroof, Ph.D. (previously a Roche postdoctoral fellow), Liz Spycher, Krisztina Oroszlan-Szovik, M.S., Helga Remy, Markus Haenggi M.S., and Marc Stawiski of Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel; Jennifer A. Steiner, Ph.D., Zachary Madaj, M.S., and Martha L. Escobar Galvis, Ph.D., of VAI; Fethallah Benmansour, Ph.D., of Roche Pharma Research and Early Development, pREDi, Roche Innovation Center Basel; Gonzalo Duran-Pacheco, Ph.D., Juliane Siebourg-Polster, Ph.D., Matthias Selhausen, Pierre Maliver, EVCP, Arel Su, DVM, and Annika Herrmann, DECVP, of Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel; Andreas Wolfert and Thomas Emrich, Ph.D., of Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Munich; and Christoph Mueller, Ph.D., of Institute of Pathology, University of Bern.

Vertebrate life began in the water, but around 340-360 million years ago, four-limbed creatures, or tetrapods, made the transition onto land. In the years that followed, some species adapted to terrestrial life, while others turned back to the water and readapted to an aquatic lifestyle.

A new study of these early amphibians, published in the journal PLOS ONE and led by Penn paleontologist Aja Carter, suggests that these environmental shifts left an impression--on the shape of the animals' spines.

"I'm interested in how the shapes of the vertebrae affect how animals move," she says. "Our findings suggest that, in at least one part of the vertebrae, the shape of the bones correlated with the environment in which the animals were living." Those associations, Carter says, may be a result of the different physical demands of living on land versus in the water.

Diversity, now and then

Many characteristics distinguish creatures as diverse as humans, dogs, snakes, and even Stegasaurus, but one thing that unites them is the basic shape of their vertebrae.

"They all have this hockey puck-shaped thing, the centrum, fused to these sticky-outy parts, the neural arch, the transverse processes," says Carter, a paleontologist who earned her doctoral degree from Penn's Department of Earth and Environmental Science in the School of Arts & Sciences and is now a postdoctoral fellow in the School of Engineering and Applied Science. "But that's not always how it's been."

Go back further in evolutionary time, Carter says, starting even before dinosaurs arose, and one will find a highly diverse set of vertebral shapes. Yet it's not clear why all this diversity was present, or why vertebrates today have landed on one basic vertebral structure almost without exception.

Scientists have long debated whether a particular vertebral shape was important for these animals to colonize land or subsequently recolonize water. To explore the question, Carter focused on early amphibians, a group known as temnospondyls, which were the most diverse tetrapods living in the Carboniferous through the late Permian, or about 360 to 250 million years ago. Some lived exclusively on land, some exclusively in water, and some were amphibious. In addition, some that were known to be terrestrial had evolved from ancestors that were aquatic, and vice versa.

"If we want to understand macro-evolutionary trends, we need a lot of specimens," Carter says. "There are about 290 species of temnospondyls, and they come in different sizes, and we know a lot about them. So this was a great group to focus on."

Shapes by the numbers

Though previous studies had used qualitative techniques to assess the relationship between vertebral form and a land- or water-based lifestyle, Carter and colleagues opted to use a quantitative approach known as geometric morphometrics. This strategy quantifies shape by assigning points to the outline of a structure. In the current study, they used a two-dimenisonal approach, imagining the outline of the vertebrae viewed from the side.

The researchers focused in particular on the shape of two parts of the vertebrae, the intercentrum, a weight-bearing structure, and the neural arch, sites of muscle attachment. Many in the field presumed that a land-based lifestyle required a stiffer spine than one in water, so the team's prediction was that terrestrial temnospondyls would have longer neural arches and longer intercentra to restrict flexibility through the spine.

Yet that's not what they discovered. Instead, they found no association between the neural arches and the environment in which they animals lived. "That suggests there is some plasticity," Carter says. In other words, there is not just one type of neural arch that enables successful movement on land.

The intercentrum shape, however, did correlate with environment and not in the way that that earlier scientists had predicted. Terrestrial species tended to have shorter, more curved intercentra, while aquatic and semi-aquatic animals had intercentra that were taller and flatter.

"The intercentra are weight-bearing, and these seem to fall out based on environment," says Carter. "But the neural arches' shape don't seem to bend to the constraints that we think of in terms of terrestrial versus aquatic."

Indeed, in terrestrial species, the researchers found some with a high degree of spinal flexibility, contrary to previous beliefs, Carter says. "In fact, in our results, a lot of terrestrial taxa seemed to have spines that were a lot less stiff than their aquatic counterparts."

In addition, aquatic species that were known to have ancestors that had lived on land maintained morphologies more akin to their terrestrial counterparts. "They don't go back," she says.

Questions for the future

Carter notes, however, that there are other ways to gain spinal flexibility, including increasing the total number of vertebrae, but the new findings still buck earlier notions of what morphologies enabled a successful move to the land.

"This tells us there is more diversity than what these labels--terrestrial, aquatic--are saying, when it comes to vertebral composition and shape," Carter says.

Carter acknowledges that paleontological studies such as these leave a lot of room for doubt. Measurements are coming from fossils that may have been reshaped during the fossilization process, for example. Plus, muscle attachments, lost to the fossilization process, would have a significant impact on movement. So she won't be surprised if future studies challenge these findings.

"Science is both iterative and overturned all the time," she says.

Yet in the not-so-distant future, in her new position at Penn Engineering, Carter hopes to build paleontologically inspired robots in which she could test how differently formed vertebrae impact funcational movement.

"I'm learning that's going to be a difficult challenge, but I'm excited to work on it," she says.

New research shows what is often assumed to be 'fair' in conservation practice may not be considered so by the very people most affected by it--and a new approach is needed if protected areas are to be effective.

Lead author Dr Georgina Gurney, from the ARC Centre of Excellence for Coral Reef Studies based at James Cook University, said considering local stakeholder conceptions of fairness in conservation is critical.

"If conservation is perceived as unfair it can lead to conflict, undermining support and cooperation," Dr Gurney said.

She said it is not only an ethical matter but key to achieving good outcomes for people and the environment.

"But what is fairness? Very few studies have asked this question in the context of conservation, especially marine protected areas."

The researchers asked Indigenous communities in Fiji (who hold customary tenure rights to land and sea) about the fairness of five alternative approaches to distributing money paid by tourists to dive in a new co-managed marine protected area.

"Our study found local stakeholders considered the 'most fair' way to distribute money from the area was according to who held rights over the area," said co-author Dr Sangeeta Mangubhai, Director of the Wildlife Conservation Society Fiji Country Program.

"They thought the least fair way to distribute money was according to the costs incurred to fishers who were affected by the new rules prohibiting fishing."

The findings challenge common assumptions in much of the conservation literature and practice about what constitutes distributional fairness. These often focus on equality and forgone economic benefits of resource extraction, such as fishing.

"Our findings help clarify fairness in global environmental policies and agreements," Dr Mangubhai said. "Explicitly identifying what is considered fair by those most affected by conservation is important during both the planning and evaluation processes."

"This practice is especially important in low- and middle-income countries. Conservation practice and policy undertaken in these countries are often shaped by that developed in rich Western countries, which means they are underpinned by Western ideas about fairness."

"As the coverage of conservation areas is expected to grow to 30% of the world's surface by 2030, more attention should be given to what local stakeholders consider is fair with regards to related decision-making and the distribution of associated costs and benefits," Dr Gurney said.

"To help make sure existing and new protected areas work, we need to move beyond tacit assumptions about what constitutes fair management to explicit identification of local conceptions of fairness."

"Otherwise, we risk the chance of support for the protected area being eroded."

Since the early days of the COVID-19 pandemic, there were questions about how people in active cancer treatment would fare if they became infected with SARS-CoV-2. The worries were due, in large part, to the effects that cancer and its treatments can have on the immune system. Now that COVID-19 vaccines are widely available, concerns have shifted to the safety and effectiveness of vaccination in this potentially vulnerable population. A study published June 5 in the journal Cancer Cell aims to allay those fears.

In a review of 200 patients with a wide spectrum of cancer diagnoses, researchers at Montefiore Health System and Albert Einstein College of Medicine in the Bronx, NY, found that after full vaccination, 94% of patients overall demonstrated seroconversion, which was determined by the presence of antibodies to the SARS-CoV-2 spike protein. Response rates were very high among patients with solid tumors and were lower in people with certain blood cancers, but even the majority of those patients mounted an immune response.

"Studies from early in the pandemic found that cancer patients who get COVID-19 have higher rates of morbidity and mortality compared to the general population," says senior co-author Amit Verma, director of the Division of Hemato-Oncology at Montefiore and professor of medicine and of developmental and molecular biology at Einstein, and associate director, translational science, Albert Einstein Cancer Center. "We really need efforts to protect these vulnerable patients from infection. This study should help people feel reassured that these vaccines work very well, even in those receiving chemotherapy or immunotherapy."

"This study confirms that there is no need for patients to wait for vaccination until they finish their chemotherapy or immunotherapy," says senior co-author Balazs Halmos (@DrSteveMartin), director of the Multidisciplinary Thoracic Oncology Program at Montefiore, professor of medicine at Albert Einstein College of Medicine, and a member of the Albert Einstein Cancer Center (AECC). "The side effects from vaccination seen in these populations were not substantially worse than in other groups. Not a single patient had to go to the emergency room or be admitted to the hospital because of side effects from the vaccines."

This study was the largest of its kind to look at seroconversion rates in cancer patients who have been fully vaccinated. Previous studies have looked at much smaller populations or have analyzed antibody levels after only the first dose of two-dose vaccines.

In serum tests to look for IgG levels after vaccination, the researchers found that among patients with solid tumors, 98% showed seroconversion. Among patients with hematologic cancers, the rate of seroconversion was 85%.

Patients receiving some treatments fared worse than others. Those receiving therapies for blood cancers that work by killing B cells (such as rituximab or CAR T therapies) had seroconversion rates of 70%. For those who had recently had bone marrow or stem cell transplants, the rate was 74%. But those rates were still much higher than expected, the researchers say.

"Although those receiving treatments that affect B cells didn't do as well, patients with blood cancers that affect the myeloid cells rather than the lymphoid cells had a pretty good response with regard to seropositivity," says first author Astha Thakkar (@asthakkar15) a Montefiore hematologic oncology fellow. "This includes people with acute myeloid leukemia and myelodysplastic syndrome."

The researchers say that one reason their data are so significant is that they include patients who had a broad range of cancers and who were undergoing a number of different treatments. "The patients themselves were also diverse and were representative of the patients we treat in the Bronx," Halmos says. "About one-third were Black and 40% were Hispanic."

"Vaccination among these populations have been lower, even though these groups were hardest hit by the pandemic," Verma concludes. "It's important to stress how well these patient populations did with the vaccines."

The routes and schedules of public transit, the presence or absence of sidewalks, the availability of different transportation options, and the design of highways that divide cities--these are examples of aspects of transportation systems that can profoundly impact underserved communities' access to basic needs like jobs, health care, education and even food.

A new study by University of Michigan researchers reveals common barriers that transportation decision-makers face in considering these issues and addressing them.

To conduct the study, a team from a multidisciplinary project involving engineering, public policy and data science interviewed 59 transportation practitioners in government, industry, the nonprofit sector and academia.

Increasing the equitable access to resources that transportation provides has risen on transportation practitioners' priority lists in recent decades, to the point that 80% of those interviewed said that they directly address social equity and fairness in their work. But common barriers they face include the need for more and better data on equity and transportation needs, as well as more effective ways to measure transportation equity.

How transportation system can perpetuate inequities

Historically, transportation systems have deepened inequity by, for instance, building highways that cut off and divide Black and low-income neighborhoods, among other decisions that prioritized the convenience of white residents. In addition to not repeating these injustices, many modern transportation practitioners view their role as having a responsibility to actively improve access to transportation. Poor mobility options can make it difficult for people in low-income communities to access healthy food, attend school, find and keep jobs, and receive adequate health care. It eats up time that people with limited resources can't afford to waste.

"There's a woman in Detroit who spends three hours riding the bus with her kid to go to school every day. That's three hours she's not earning the money that might help her move closer to that school or buy a car to reduce the commute. It's three hours she can't spend preparing healthy food, from a grocery store that might be as inaccessible as the school, and could lead to long term health problems. These inequities stack," said Kaylla Cantilina, a Ph.D. student in design science and first author on the paper in the journal
Transportation Research Record.

Barriers to progress in transportation equity

Practitioners cited these crucial barriers to improving transportation equity:

Collecting and connecting data sets: Policymakers said they couldn't get access to data in private companies, and private companies said that they couldn't seamlessly connect public data sets with their own data.

Lack of information on needs: Transportation practitioners need more information about the gaps experienced by underserved communities--where they need to go, when they need to go there and why current services are inadequate. In some cases, moving people won't be the sole solution. Cities may need to work with schools, hospitals and grocery stores to support the populations that need them.

"A lot of problems aren't purely transportation, but if we get more information about those problems, then we can address the pieces that relate to transportation," Cantilina said..

How better communication could lead to solutions

One potential solution is to improve communication between engineers and policymakers, and between data scientists and policymakers.

"Transportation equity practitioners, including engineers and data scientists, cannot develop solutions isolated from contexts and communities," said Shanna Daly, U-M associate professor of mechanical engineering who co-authored the paper.

"Transportation work has both technical and social dimensions that must be considered in parallel, even in disciplines that have been conventionally 'boxed off' as having only a technical focus."

As for how to facilitate those connections, some practitioners shared their approaches that could serve as models--such as a partnership between a city and a ride-sharing or automotive company to share data under agreed-upon parameters. Another example came from a state metropolitan planning organization, which handles regional mapping, allocation of funding and regulation of transportation around cities. The organization has an open office in which departments are mixed, making it easy to solicit knowledge without asking for a meeting.

One of the surprises was that for more than half of the transportation practitioners, money wasn't considered a major barrier. But reallocating money from other projects was often a challenge. Transportation decision-makers need structures in place to advocate for apportioning money with equity in mind, the researchers said.

"If you have a clump of money that automatically goes to highway management, is it really that hard to convince people not to use all of it for the highway? Why can't we build a sidewalk on this low-income road so kids can walk to school safely? It's a matter of priority," Cantilina said.

Closing the gap between academic researchers and practitioners

The study uncovered gaps between academic research and transportation practice. Often, the academic research in transportation equity focuses on approaches and tools that are not always easily applied, Cantilina said. Meanwhile, practitioners aren't necessarily taking advantage of the groundwork laid in research, though they sometimes come to the same conclusions.

In addition, academic researchers aren't aware of many of the problems that transportation practitioners in governments, nonprofits and private companies run into. With better connections, researchers could look into more relevant questions and practitioners could avoid reinventing the wheel. One open question is how to measure transportation equity.

Better solutions would free up talent that is currently stuck at home or lost to excessively long bus rides.

"Transportation is a form of freedom," Cantilina said. "You don't have time to dream when you're trying to access the resources just to survive."

A new study conducted by the researchers at the University of Liverpool reveals how the ancient photosynthetic organisms - cyanobacteria - evolve their photosynthetic machinery and organise their photosynthetic membrane architecture for the efficient capture of solar light and energy transduction.

Oxygenic photosynthesis, carried out by plants, algae, and cyanobacteria, produces energy and oxygen for life on Earth and is arguably the most important biological process. Cyanobacteria are among the earliest phototrophs that can perform oxygenic photosynthesis and make significant contributions to the Earth's atmosphere and primary production.

Light-dependent photosynthetic reactions are performed by a set of photosynthetic complexes and molecules accommodated in the specialised cell membranes, called thylakoid membranes. While some studies have reported the structures of photosynthetic complexes and how they perform photosynthesis, researchers still had little understanding about how native thylakoid membranes are built and further developed to become a functional entity in cyanobacterial cells.

The research team, led by Professor Luning Liu from the University's Institute of Systems, Molecular and Integrative Biology, developed a method to control the formation of thylakoid membranes during cell growth and used state-of-the-art proteomics and microscopic imaging to characterise the stepwise maturation process of thylakoid membranes. Their results are published in the journal Nature Communications.

"We are really thrilled about the findings," said Professor Liu. "Our research draws a picture about how phototrophs generate and then develop their photosynthetic membranes, and how different photosynthetic components are incorporated and located in the thylakoid membrane to perform efficient photosynthesis - a long-standing question in this field."

The first author of the study, Dr Tuomas Huokko, said: "We find that the newly synthesised thylakoid membranes emerge between the peripheral cell membrane, termed the plasma membrane, and the pre-existing thylakoid layer. By detecting the protein compositions and photosynthetic activities during the thylakoid development process, we also find that photosynthetic proteins are well controlled in space and time to evolve and assemble into the thylakoid membranes."

The new research shows that the cyanobacterial thylakoid membrane is a truly dynamic biological system and can adapt rapidly to environmental changes during bacterial growth. In thylakoids, photosynthetic proteins can diffuse from one position to another and form functional "protein islands" to work together for high photosynthetic efficiency.

"Since cyanobacteria perform plant-like photosynthesis, the knowledge gained from cyanobacteria thylakoid membranes can be extended to plant thylakoids," added Professor Liu. "Understanding how the natural photosynthetic machinery is evolved and regulated in phototrophs is vital for tuning and enhancing photosynthetic performance. This offers solutions to sustainably improve crop plant photosynthesis and yields, in the context of climate change and growing population. Our research may also benefit the bioinspired design and generation of artificial photosynthetic devices for efficient electron transfer and bioenergy production."

Laser-produced high energy density plasmas, akin to those found in stars, nuclear explosions, and the core of giant planets, may be the most extreme state of matter created on Earth. Now scientists at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL), building on nearly a decade of collaboration with the National Ignition Facility (NIF) at the DOE's Lawrence Livermore National Laboratory (LLNL), have designed a novel X-ray crystal spectrometer to provide high-resolution measurements of a challenging feature of NIF-produced HED plasmas.

Most powerful lasers

The collaboration with NIF, home to the world's largest and most powerful lasers, represents a major expansion for PPPL's X-ray crystal spectrometer designs, which are used by fusion laboratories around the world to record on detectors the spectrum of X-rays from the plasma - gases of electrons and atomic nuclei, or ions -- that fuel fusion reactions. These PPPL instruments measure profiles of key parameters such as the ion and electron temperatures in large volumes of hot plasmas that are magnetically confined in doughnut-shaped tokamak fusion devices to facilitate fusion reactions. By contrast, NIF laser-produced HED plasmas are tiny, point-like substances that require differently designed spectrometers for high-resolution studies.

"We previously built a spectrometer for the NIF that has been quite successful," said physicist Manfred Bitter, a long-time member of the PPPL design team. That spectrometer, delivered in 2017, provides high-resolution measurements of the temperature and density of NIF extreme plasmas for inertial confinement fusion experiments, and the data obtained have been presented in invited talks and peer-reviewed publications.

The HED experiments differ from the magnetically confined experiments that PPPL conducts in many respects. A major difference that affects the design of spectrometers is the small size of laser-produced HED plasmas, whose volumes are typically on the order of a cubic millimeter and can be considered as point-like X-ray sources. This small size compares with extended tokamak plasmas, which have volumes of several cubic meters and require very different diagnostic designs.

New design challenges

PPPL's new spectrometer for the NIF responds to new design challenges. They call for measuring a fine structure in the X-ray spectra of HED plasmas that reveals their state of matter under extreme conditions. Such measurements can show whether the ions in the highly-compressed plasma are in a random, or fluid-like arrangement, or in a more ordered lattice-like arrangement that is typical for a solid.

This critical state of matter can be detected in what is called the Extended X-ray Absorption Fine-Structure (EXAFS) -- the technical term for the tiny intensity variations, or wiggles, in the X-ray energy spectrum recorded by crystal spectrometers. "The standard crystal forms which have been used for the diagnosis of HED plasmas, so far, cannot be used in this case," said Bitter, lead author of a paper in the Review of Scientific Instruments that describes the PPPL spectrometer being fabricated for the NIF. "Their resolution and photon throughput are not high enough and they introduce imaging and other errors."

These are the challenges the new crystal spectrometer must meet, Bitter said:

To reduce statistical errors, the design must be adapted to a high throughput of photons, the particles of light that X-ray sources and all other light sources emit. The X-ray reflecting crystal must therefore have a large area without introducing any of the imaging errors that large standard crystals tend to produce.

The crystal must reflect the wide range of X-ray energies over which the fine structure is observed.

Finally, the crystal and detector arrangements must minimize the effects of what is called source-size broadening. This problem results from the tiny, but not negligible, size of a laser-produced HED plasma that deteriorates, or muddles, the spectral resolution. The standard crystal forms that have been used until now cannot fully eliminate or minimize these broadening effects.

Bitter and PPPL physicist Novimir Pablant worked together to design the new spectrometer. Bitter came up with the idea of shaping the crystal that mirrors the spectrum in the form of what is called a sinusoidal spiral. These spirals denote a family of curves whose shapes can be determined to assume any real value, making it possible to select a special shape of crystal. Pablant, who co-authored the Review of Scientific Instruments paper, created a computer code to design the sinusoidal crystal in a process that he outlines in a recently submitted companion paper to the same journal.

"I developed a code that would allow me to model the complicated 3-D shape of the crystal and simulate the performance of this new spectrometer design," Pablant said. The simulations showed that the performance of the crystal marked "a five-times improvement in energy resolution for this NIF project compared to their previous spectrometer design."

The collaboration will move to NIF in October when the new spectrometer is scheduled for testing there, with researchers at both laboratories eagerly awaiting the results. "Experiments at the NIF that measure the EXFAS spectrum at high X-ray energies have had low signals," said Marilyn Schneider, leader of the Radiative Properties Group at the Physics and Life Sciences Directorate of LLNL and a co-author of the paper. "The spectrometer design described in the paper concentrates the low signal and increases the signal-to-noise ratio while maintaining the high resolution required for observing EXAFS," she said.

Experimental verification is the next step required. "We arrived at this design after several attempts and are confident that it will work," said Bitter. "But we have not yet tested the design at NIF and must see how it performs in the fall."

Two gene variants found in African American women may explain why they are more likely to be diagnosed with triple negative breast cancer (TNBC) than white women of European ancestry, according to Weill Cornell Medicine and NewYork-Presbyterian investigators. The study findings may have implications for developing better risk assessment tools for TNBC in African American women and for understanding why they have poorer TNBC outcomes.

In a study, published April 29 in Scientific Reports, the investigators found that a version of the ANKLE1 gene that can be protective against TNBC is less likely to be found in African American women than white women of European ancestry. In addition, African American women with a mutation in the Duffy gene, which plays a role in inflammation, have a higher risk of TNBC.

"While more white women are diagnosed with breast cancer, African American women are more likely to die from the disease," said Dr. Melissa B. Davis, who was recruited to Weill Cornell Medicine as an associate professor of cell and developmental biology research in surgery, and is scientific director of the International Center for the Study of Breast Cancer Subtypes (ICSBCS). Moreover, African American women have twice the risk of developing TNBC than white women of European ancestry.

Historically, genetic studies of breast cancer have not included enough information about people of African descent, Dr. Davis said. This lack of data contributes to problems with understanding some of the less common versions of genes, or genetic mutations that are found in populations that are not of European descent.

To help address this problem, Dr. Davis and her research team analyzed genetic information from the ICSBCS cohort. The scientists collected DNA from saliva samples in 120 breast cancer patients from Ghana and Ethiopia. Additional samples were collected from 193 African American and 184 European American women with breast cancer. Dr. Davis's team also collected data from 271 healthy controls in the United States and Ghana. The team then assessed the effect in these patients of different gene versions, known as alleles, that had been previously associated with breast cancer risk.

"We have this African-enriched cohort where we've assessed genetic ancestry, and this includes patients and case controls of African ancestry, which is unlike any other study," said Dr. Davis, acknowledging the work of her research partners in Ghana and Ethiopia over the last 17 years, as part of the ICSBCS. The center was founded by co-author Dr. Lisa Newman, chief of the Section of Breast Surgery at Weill Cornell Medicine and NewYork-Presbyterian/Weill Cornell Medical Center, who was recruited to Weill Cornell Medicine as a professor of surgery.

The researchers found two risk alleles previously defined by the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium were replicated in the ICSBCS study group of patients. Dr. Davis's team validated that an ANKLE1 variant is protective against TNBC but that African American women are more likely to have a version that may be oncogenic, or cancer causing.

ANKLE1 has not been thoroughly studied in cancer yet. "Part of the reason would be that it's under the radar," Dr. Davis said. "It's a risk allele that was only identified when looking at African-Americans and Africans."

ANKLE1 appears to have DNA repair properties like the BRCA gene. BRCA has enzymatic activity that helps to correct mistakes in DNA leading to cancer. Mutations in the gene increase breast cancer risk and physicians often recommend screening for mutations in BRCA in the Ashkenazi Jewish population in which it appears at higher rates. The researchers' current findings on ANKLE1 should inform breast cancer risk models in African American women, Dr. Davis said.

The researchers also verified that a mutation in the Duffy gene, known for its role in inflammation and tumor biology, was associated with an increased risk of TNBC in African American women. The mutation causes the gene to lose function and is what researchers call a null allele. "I would like women to be more informed about their Duffy-null status," Dr. Davis. "If you have that status, you have a higher likelihood of developing triple negative breast cancer, if you get breast cancer," she said.

A better genetic understanding of breast cancer in African American women can help to inform treatment. "Genetic signature tests can predict whether or not patients have a high risk of recurrence or high risk of having a refractory tumor," Dr. Davis said. "Doctors can then determine whether the current standard of care is going to be effective or if they need to adjust the treatment plan for better outcomes."

Organic residues on ceramic pottery are a valuable resource for understanding medieval cuisines of Islamic-ruled Sicily, according to a study published June 9, 2021 in the open-access journal PLOS ONE by Jasmine Lundy of the University of York, UK and colleagues.

During the 9th to 12th century AD, Sicily was under Islamic rule. This transition is known to have profoundly impacted the region, and the capital city of Palermo thrived as an economic and cultural center of the Mediterranean Islamic world. But little is known about how the lives of people in the region were impacted during this important time period.

In this study, researchers examined organic residues of plant and animal products on ceramic pottery to gain insights into the cuisine of the time.

They tested 134 cooking pots and other similar containers, dating between the 9th and 12th century AD, from the urban city of Palermo and the rural town of Casale San Pietro. The results indicate a wide variety of vegetables, fruits, beeswax and animal food products, complementing other archaeological evidence. The authors highlight some notable differences between rural and urban cuisines, including the greater frequency of grapes and dairy products in the rural site.

This study is a profound demonstration of the utility of organic residue analysis for understanding cuisine of Islamic ruled Sicily. The mixture of a diverse assortment of food products is consistent with the colorful dishes noted in Arabic literature, and the differences observed between rural and urban sites suggests there is more to be learned about how cultures differed across Sicilian society. Further studies using similar techniques will expand our understanding of how cuisine preferences and use of ceramics changed while Sicily was under Islamic rule.

The authors add: "Analysis of residues preserved in pottery has, for the first time, revealed important insight into cuisine in medieval Islamic Sicily. We have identified a diverse range of products processed in cooking wares, as well as regional differences in the use of ceramics such as for the processing of dairy and grapevine products."

The moons of planets that have no parent star can possess an atmosphere and retain liquid water. Astrophysicists at LMU have calculated that such systems could harbor sufficient water to make life possible - and sustain it.

Water - in liquid form - is the elixir of life. It made life possible on Earth and is indispensable for the continuing existence of living systems on the planet. This explains why scientists are constantly on the lookout for evidence of water on other solid bodies in the Universe. Up to now, however, the existence of liquid water on planets other than Earth has not been directly proven. However, there are indications that several moons in the outer reaches of our own solar system - more specifically, Saturn's Enceladus and three of Jupiter's moons (Ganymede, Callisto and Europa) may possess subterranean oceans. What then are the prospects for the detection of water on the moons of planets beyond our solar system?

In cooperation with colleagues at the University of Concepción in Chile, LMU physicists Prof. Barbara Ercolano and Dr. Tommaso Grassi (both of whom are members of ORIGINS, a Cluster of Excellence) have now used mathematical methods to model the atmosphere and gas-phase chemistry of a moon in orbit around a free-floating planet (FFP). An FFP is a planet that is not associated with a star.

More than 100 billion planetary nomads

FFPs are of interest mainly because the evidence indicates that there are plenty of them out there. Conservative estimates suggest that our own galaxy hosts at least as many Jupiter-sized orphan planets as there are stars - and the Milky Way itself is home to well over 100 billion stars.

Ercolano and Grassi made use of a computer model to simulate the thermal structure of the atmosphere of an exomoon of the same size as the Earth in orbit around a FFP. Their results suggest that the amount of water present on the moon's surface would be about 10,000 times smaller than the total volume of our planet's oceans, but 100 times larger than that found in Earth's atmosphere. This would be enough to enable life to evolve and thrive.

The model from which this estimate was derived consists of an Earth-sized moon and a Jupiter-sized FFP. Such a system, which has no stellar companion nearby, is expected to be dark and cold. Unlike our solar system, there is no central star that can serve as a reliable source of energy to drive chemical reactions.

Cosmic radiation and tidal forces to the fore!

Rather, in the researchers' model, cosmic rays provide the chemical drive necessary to convert molecular hydrogen and carbon dioxide into water and other products. To keep the system stirred up, the authors invoke the tidal forces exerted by the planet on its moon as a source of heat - and assuming that carbon dioxide accounts for 90% of the moon's atmosphere, the resulting greenhouse effect would effectively retain a large part of the heat generated on the moon. Together, these energy sources would suffice to keep water in the liquid state.

The presence and accumulation of the antioxidant pigment anthocyanin dictates fruit hue in plums, and the synthesis of this compound is known to be regulated by the MYB10 genes. Now, researchers from the Centre for Research in Agricultural Genomics (CRAG) and the Institute of Agrifood Research and Technology (IRTA) have found the gene that determines Japanese plum skin colour. In a study published at the scientific journal Frontiers in Plant Science, the team reveals that the plum genome contains several copies of the MYB10 genes, and that DNA variations in one of these copies cause plums to have anthocyanins in the skin (showing a blue to red colour) or not (presenting a yellow or green tone).

The Japanese plum, highly appreciated for its juiciness, is the most abundant on the market for direct fresh consumption, and Spain is one of its largest producers in the European Union, with plum trees mainly grown in the regions of Extremadura, Andalusia and Murcia. This new study provides a highly efficient tool for early selection of coloured and non-coloured fruits in Japanese plum breeding programmes, an advancement aligned with the goals of the International Year of Fruits and Vegetables (IYFV), designated by the UN General Assembly, to increase efficiency in fruit food systems and to promote healthy nutrition through fruit consumption.

Anthocyanins: more than colour

The red to blue hue of flowers and fruits is due to anthocyanins, a group of antioxidant pigments that enhance flower pollination and provide plants protection from light damage and dehydration. Including these healthy antioxidants in our diet has been linked to anti-carcinogenic and anti-inflammatory effects, and to the prevention of cardiovascular diseases, diabetes and obesity.

Apples, pears, peaches, apricots, plums, cherries and strawberries, all of which belong to the Rosaceae family, are broadly considered a source of anthocyanins, contained in their skin and flesh. As fruit colour has both an important impact in consumer choice and nutritional quality, it is not surprising that there is considerable interest in breeding these crops to obtain new varieties bearing fruits with diverse colours, hues and patterns while enhancing their health benefits.

Focusing on the Japanese plum

Within the Rosaceae crops, Japanese plum is among those with the highest fruit colour variation both in hue and pattern, going from anthocyanin-less green and yellow to red, purple or blue. &laquoPrevious studies in Rosaceae species show that the synthesis and accumulation of anthocyanins is regulated by the MYB10 genes. Accordingly, the analysis of these genes in several Japanese plum has been proven to be an excellent model to understand how fruit colour is determined», indicates Arnau Fiol, PhD student at CRAG and first author of the article.

&laquoIn this study, we examined the MYB10 genes in a panel of Japanese plum varieties and we found that they are highly variable. Surprisingly, we discovered that some cultivars have three copies of one of the MYB10 genes, which adds up to the already complex analysis of plum colour variation», explains Maria José Aranzana, IRTA researcher at CRAG in charge of this work. &laquoBy studying how these gene variants are inherited, we were able to identify which gene variant combinations are associated with the anthocyanin (red to blue) and anthocyanin-less (green or yellow) fruit skin colorations», she adds.

Boosting the development of new varieties

Imagine we want to develop a new blue plum variety with lots of anthocyanins to benefit from its nutraceutical properties. New fruit tree varieties are obtained in breeding programmes by crossing individuals and examining the hundreds or thousands of descendants looking for those that present the desired trait, say a bluer plum, and that also meet demanding product quality standards. Between 10 and 20 years may pass from the first cross until the registration of a new variety, as it takes a long period for trees to bear fruits (about 3 to 4 years in plum trees) and they must pass several exhaustive evaluations.

&laquoIn our work, we have identified the gene variants that cause anthocyanins to accumulate or not in Japanese plum skin. This means that, by just studying the seedlings' DNA, we can efficiently predict the skin colour of the fruits they will bear as soon as the plants germinate, allowing us to promptly discard all the seedlings that will produce green fruits. Thanks to this early screening, we'd need a smaller growing area and fewer resources (hydric, nutritional, phytosanitary and human) to obtain the desired new anthocyanin-rich plum variety, with the consequent economic and environmental benefits», points out Aranzana.

The reliable molecular marker for early selection of coloured and non-coloured Japanese plums developed in this research can be effectively used in breeding programmes. Anticipating at a seedling level the colour of the fruit that plants will produce in 3-4 years significantly shortens and optimizes the breeding process. Since the mechanism underlying variation in fruit colour is conserved within the Rosaceae family, this tool holds promising prospects for anthocyanin-determined colour selection in other related species of agronomic interest.

To focus on what's new, we disregard what's not. A new study by researchers at MIT's Picower Institute for Learning and Memory substantially advances understanding of how a mammalian brain enables this "visual recognition memory."

Dismissing the things in a scene that have proven to be of no consequence is an essential function because it allows animals and people to quickly recognize the new things that need to be assessed, said Mark Bear, Picower Professor in the Department of Brain and Cognitive Sciences and senior author of the study in the Journal of Neuroscience.

"Everyone's appropriate behavioral response to an unexpected stimulus is to devote attentional resources to that," Bear said. "Maybe it means danger. Maybe it means food. But if you learn that this once-novel stimulus isn't anything of significance, it is super adaptive to no longer pay attention to it. It's absolutely essential for normal brain function that we're able to make a quick determination of whether a stimulus is novel or not."

People with schizophrenia and some autism spectrum disorders appear to struggle with this capability, Bear noted.

In 2006 Bear's lab discovered the first sign of visual recognition memory. Researchers detected a strong pattern of increasing electrical activity in the visual cortex as mice became familiar with an image on a screen. Subsequent research showed that this increase in electrophysiological response, dubbed SRP, or "stimulus selective response plasticity," correlated strongly with "habituation," or the behavioral loss of interest in exploring the increasingly familiar stimulus.

Since then, the lab has been working in mice to understand exactly how these phenomena emerge. Their research has shown that a well-known mechanism of learning and memory called "LTP," a strengthening of neural connections amid frequent activity, is involved but that this mechanism alone cannot produce visual recognition memory. Inhibitory neurons called parvalbumin (PV) expressing neurons also appear to be crucial parts of the circuit. PV neurons are known to produce high frequency gamma rhythms in the cortex.

In the new study led by graduate students Dustin Hayden and Daniel Montgomery, Bear's lab shows that as novel visual patterns become familiar, the transition is marked by stark changes in the visual cortex. Gamma rhythms give way to lower frequency beta rhythms and the activity of PV neurons dies out in favor of a rise in activity by inhibitory somatostatin (SOM) expressing neurons.

The study, Bear said, therefore provides an externally measurable indicator of the transition from novel to familiar - the brain rhythm shift. It also offers a new hypothesis for how visual recognition memory is enforced: PV activity, which initially inhibits the SRP electrical response, eventually itself becomes inhibited by SOM activity.

Bear's lab is working with Boston Children's Hospital researcher Chuck Nelson to determine if aberrations in SRP, such as this frequency transition, can be used as an early biomarker of autism spectrum disorders.

Same old scene

In the new study, the researchers showed mice the same simple image repeatedly over the course of several days. All the while they measured the SRP electrical response in the mice as well as neural rhythms. In parallel experiments, they engineered some mice so that their PV or SOM neurons would flash brightly when active. Then as mice watched the image, the scientists could watch for those flashes using a "two-photon" microscope.

On day one, when the image was novel, the spectrum of rhythms in the visual cortex was dominated by higher frequency gamma readings. As the days went on, gamma power diminished, replaced by a steady increase in low frequency beta power. To ensure this wasn't an unrelated transition, on day seven the scientists presented a new image and the familiar one. When the mice saw the new one, they again exhibited a gamma frequency dominated pattern. When they saw the same old original image, the visual cortex reproduced the pattern of increased beta power.

In a subsequent data analysis, the researchers found that the decline in gamma power and increase in beta power correlated significantly with the SRP growth of electrical activity, suggesting that they are indeed linked.

"These data are compatible with the hypothesis that the same underlying biology is responsible for both manifestations of SRP," the researchers wrote.

The two-photon microscope experiments revealed that underlying biology difference. PV neurons responded strongly to images when they were novel but that activity became replaced by increasing SOM activity over several days as the image became familiar.

SOM neurons are believed to suppress PV neurons, Bear said, but to prove that SOM inhibition of PV accounts for visual recognition memory, the lab still needs to perform more experiments. Using optogenetics, in which they can engineer neurons to be controlled with different colors of light, they can manipulate SOM neurons to see if turning them off causes mice to regard repeated images as forever new, or turning them on causes mice to immediately dismiss novel images as passe.

New research by scientists at Oxford Brookes University has identified specific genes which could provide vital information about the biology of developmental coordination disorder (DCD), also known as dyspraxia. Dyspraxia is a common motor coordination condition which is estimated to affect at least one child in every classroom.

DCD can impact a child's handwriting and coordination skills such as tying a shoelace or catching a ball. The condition can limit school achievement, impact cognitive development, constrain career opportunities and increase children's risk of developing mental health issues.

Despite the condition affecting five per cent of children, as common as dyslexia or autism, very little is known about why some children struggle with motor coordination.

Genetic data research is first step in understanding causes of DCD

Scientists examined genetic data from over 4,000 participants in the Avon Longitudinal Study of Parents and Children who had their motor coordination tested when they were seven years old. These data were used to link common genetic variants with motor coordination difficulties, allowing them to better understand the genetic and cellular processes that are involved in DCD.

The researchers say that this is the first step in understanding the causes of DCD.

"If we can identify genes, we can use this information to understand why some children develop DCD," says Dr Hayley Mountford, Research Fellow in the Department of Biological and Medical Sciences at Oxford Brookes University and lead author of the study.

Clear potential to unravel the biology of DCD

Many children with motor coordination difficulties remain undiagnosed and coupled with a lack of research, this has a vast impact on the visibility of DCD in both the public and the medical community.

"Although this is a preliminary study, these findings show a clear potential for genetics studies to unravel the underlying biology of DCD," adds Dr Mountford. "We need to replicate these findings in larger datasets to uncover the reasons why some children are at a higher risk. This will lead to developments in the diagnosis of DCD, improving the lives of affected families."

A new review published in the Journal of Internal Medicine indicates that unmasked speech in confined spaces poses the greatest risk of spreading SARS-CoV-2, the virus that causes COVID-19, to others.

The focus of the review is on the interface between physics and medicine, and it describes how different sized respiratory droplets emitted while speaking span a continuum of sizes and can carry different amounts of virus. Most concerning are intermediate-sized droplets that remain suspended in air for minutes and can be transported over considerable distances by convective air currents.

"We've all seen some spit droplets flying when people talk but there are thousands more, too small to be seen by the naked eye. When the water evaporates from such speech-generated, potentially virus-rich droplets, they float in the air for minutes, like smoke, thus putting others at risk," said senior author Adriaan Bax, PhD, of the National Institute of Diabetes and Digestive and Kidney Diseases.