Brain

Females are able to clear asymptomatic malaria infections at a faster rate than their male counterparts, says a study published today in eLife.

The findings, originally posted on the preprint server medRxiv*, suggest that biological sex-based differences are an important factor for epidemiologists to consider in the human response to malaria parasites.

Malaria remains a significant global health challenge, with infections causing disease symptoms that range from uncomplicated to severe. Additionally, asymptomatic malaria infections are common in places where the disease occurs most often, known as endemic areas. Due to partial immunity, individuals can carry parasites for long periods of time while unaware that they are infected.

It is well established that chronic asymptomatic infection with the most common and fatal malaria parasite, Plasmodium falciparum (P. falciparum), can cause morbidity in those infected and contribute to ongoing disease transmission. As these infections represent an important part of the parasite reservoir and are therefore a major obstacle for efforts to eliminate malaria, characterising them is crucial.

"While it is widely recognised that pregnant women have increased susceptibility to malaria infection and more severe outcomes, less attention has been paid to the possibility of other biological sex differences in malaria immunity," says lead author Jessica Briggs, Clinical Fellow in Infectious Diseases, UC San Francisco, US. "This is despite multiple studies demonstrating males are more frequently found to be infected when you go out and check in a community."

Understanding the immune response of humans to chronic P. falciparum infection requires frequent follow up of infected individuals, sensitive detection of parasites, and the ability to distinguish 'superinfection' from a persistent infection. Superinfection is common in endemic areas and refers to an individual acquiring a new infection when they are already infected.

In their study, Briggs and the team followed a representative group of people living in a malaria-endemic area of eastern Uganda. Using a genetic sequencing technique called amplicon deep-sequencing, they estimated both the rate of new infections and duration of chronic asymptomatic malaria infections in the group and compared these measures by sex.

Previous studies have reported a higher prevalence of malaria infection in males compared to females, which was also seen in this cohort. Since females had a lower prevalence of infection, but a similar rate of new infections compared to males, the team looked at whether there was a difference between the sexes in how quickly they were able to clear infections. "Our analysis revealed that asymptomatic infections cleared naturally - as in, when individuals were not treated by antimalarials - at nearly twice the rate in females versus males," Briggs says.

The authors add that these findings come with some limitations. For example, as co-senior author Isabel Rodriguez-Barraquer, Assistant Professor of Medicine at UC San Francisco, says: "There may be other unmeasured factors that affect our results, such as genetic differences or sex-based differences in the use of unreported outside antimalarials."

Despite these limitations, the authors say their findings should encourage scientists to better characterise sex-based differences in malaria. "Our next job is to unearth the underlying biological explanations for these sex-based differences in the human response to malaria," concludes co-senior author Bryan Greenhouse, Associate Professor of Medicine at UC San Francisco. "We have just begun a systems-based approach to comprehensively evaluate the immune response over time in a new study based in Uganda."

DAVIS, Calif., Oct. 27, 2020 - While an infant's genes distinguish her from other newborns, a new peer-reviewed study reports that specific genes of a particular infant gut bacterium determine its symbiotic function in the infant gut. The study provides important guidance for clinicians when selecting a probiotic for use in infants to maximize impact on both short- and long-term health outcomes.

In the first study to provide a genetic analysis of various strains of the infant probiotic bacteria Bifidobacterium longum subsp. infantis (B. infantis), researchers report that one particular strain of probiotic B. infantis, EVC001, possesses the genetic make-up that enables full metabolism of the nutritional components of human breast milk, the first step in providing important health benefits to the infant. The paper was published in the peer-reviewed journal Nutrients.

"Gut bacteria are living organisms, and thus have different genes that determine how they function. What we've revealed in this paper is a truly elegant mechanism of action that is unique to EVC001 among the probiotic strains that were studied; it's a striking distinction that defines clear genetic differences that make some B. infantis strains far more beneficial to the health of infants than others," said Rebbeca Duar, Ph.D., lead study author and senior scientist, Evolve BioSystems., Inc.

B. infantis EVC001 has been documented for its critical role in restoring function and resolving dysbiosis by suppressing potentially pathogenic bacteria in newborns, supporting immune and gastrointestinal system development, and reducing intestinal inflammation. Infant gut dysbiosis has been linked to the development of necrotizing enterocolitis (NEC), asthma, eczema, food allergies, and Type-1 diabetes.

B. infantis EVC001 provides health benefits to infants by optimally metabolizing components of breast milk called human milk oligosaccharides (HMO) into lactate and acetate, which in turn lowers the pH of the infant gut to a protective range. As a result, EVC001 has been shown to effectively suppress the abundance of pathogenic bacteria in the infant gut, reducing intestinal inflammation and lowering antibiotic resistance in both term and pre-term infants.

The researchers studied 14 different strains of B. infantis sourced from commercially available infant probiotic products as well as bacterial culture banks. Each bacterial strain underwent DNA sequencing based on the presence or absence of the H5 gene cluster, which contains key genes involved in the transport of HMOs into the bacterial cell, where it then undergoes deconstruction and metabolism.

Researchers then measured the growth rates of each strain on HMO(s), correlating the growth rates to the H5 genetic profiles of each bacterial strain to determine the ability to metabolize and utilize all HMOs as a fuel source.

Of the 12 commercial probiotic strains of B. infantis studied, one strain in particular, known as EVC001, showed twice as much growth than the other strains, and within one day had outgrown all other strains analyzed. Study authors note that growth and colonization of this bacteria correlate to optimal infant gut health.

"The importance of the infant gut microbiome for the health of babies has been widely documented, and the use of infant probiotics in the therapeutic portfolio is growing," said Dr. Duar. "This research represents a critical step forward by demonstrating that there are clear genetic and functional differences among different strains of B. infantis. In short, strain matters, since the choice of a particular strain will significantly impact the clinical and health benefits B. infantis will bring to the baby."

About Evolve BioSystems, Inc.

Evolve BioSystems, Inc. is a privately held microbiome company dedicated to researching solutions to establish, restore, and maintain a healthy gut microbiome. Evolve is a portfolio company of the Bill & Melinda Gates Foundation and Horizons Ventures, the venture division of the Li Ka Shing Foundation. Evolve is a spin-off from the Foods for Health Institute (FFHI) at the University of California, Davis and builds on more than a decade of research into understanding the unique partnership of the infant gut microbiome and breast milk components.

Boulder, Colo., USA: Across the western U.S., severe wildfires fueled by tinder-dry vegetation have already burned more than 3.2 million hectares (8 million acres [as of the time of this press release]) -- an area the size of Maryland -- in 2020, and nearly six times that area burned this year in Australia. And even though neither country's worst-ever fire year is not yet over, concerns are already mounting regarding the next hazard these regions will face: dangerous and destructive debris flows.

Debris flows are fast-moving slurries of soil, rock, water, and vegetation that are especially perilous because they usually occur without any warning. Some debris flows are powerful enough to cart off everything in their paths, including trees, boulders , vehicles -- and even homes.

Two years ago in Montecito, California, 23 people were killed and more than 400 homes damaged by a series of debris flows spawned by intense rain falling on hills scorched by what at the time had been the largest fire in California history.

To better understand the origin of these hazards, researchers at the U.S. Geological Survey (USGS) studied slope failure at two sites in Southern California's San Gabriel Mountains. The first site burned in 2016 during the San Gabriel Complex fire, whereas a second, nearby site was charred during the 2014 Colby fire. The findings, presented Wednesday during the annual meeting of The Geological Society of America, indicate there were major differences in slope failure between the first and the third years following incineration. The results will help inform land managers and residents about when and where debris flows and other types of slope failure are more likely to occur.

"In the first year after each fire, we observed debris flows generated by rainfall runoff," says Francis Rengers, a USGS research geologist who led the study. "But as we continued monitoring, we were surprised to see that a storm with a higher rainfall intensity than the first year's storms, resulted in more than 280 shallow landslides, rather than debris flows, in the third year."

In contrast to debris flows, which have fluid-like behavior, landslides glide as cohesive masses along a rupture plane. The researchers, including scientists from the University of Arizona, the Desert Research Institute, the USGS, and the German Research Centre (GFZ) believe this difference is due to changes in how much water can infiltrate into the ground during storms that follow wildfires. Because severe wildfires make soils more water-repellent, Rengers says, rainfall tends to run off burned ground. "If water is not soaking in," he explains, "it's flowing over the surface." By removing ground cover, wildfires also reduce a hillslope's roughness, which helps the slurry pick up speed. Incineration can also allow rainfall on bare soil to create what he calls a "surface seal" that further increases runoff.

Because landslides have much shorter runouts than debris flows, they pose different hazards. "The landslides we observed would primarily impact local infrastructure in the forest, such as roads, transmission lines, and culverts," Rengers explains. By contrast, he says, debris flows move sediment much further downstream and therefore pose a hazard beyond the steep, mountainous hillslopes. "Runoff-generated debris flows threaten lives and property, including homes," he says.

The results offer a ray of hope that the threat of slope failure has a limited duration: the researchers found that within five years, the density of landslides on burnt slopes in the San Gabriels was nearly equal to the density in unburned regions. This indicates the vegetation in this region recovers within half a decade.

Based on these observations, the researchers have developed a new conceptual model of post-wildfire slope failure that has three distinct stages. During the 'no-recovery' phase, increased runoff makes debris flows more prevalent. Within a couple of years, increasing water percolation, combined with the decay of roots from vegetation destroyed in the fire, make the slopes more susceptible to landsliding during the 'initial recovery' stage. After about five years, new roots become established enough to stabilize the hillside in the final 'fully recovered' phase.

In the future, the researchers plan to investigate whether this same model applies to other regions, such as the Rockies and the Pacific Northwest, which also experienced severe wildfires this year. For now, the results have immediate and practical applications for land managers who are dealing with the 2020 aftermath. "Our model suggests that debris flows will be the primary concern during the next one to two years, at least in the burn scars in Southern California, and after that the concern will shift toward shallow landslide hazards" says Rengers. "I hope our work offers land managers useful expectations regarding how these processes are likely to evolve and helps them prioritize post-wildfire mitigation and planning."

Tsukuba, Japan - In a study recently published in ACS Applied Polymer Materials, researchers from the University of Tsukaba synthesized an infrared-transmitting polymer--based on low-cost, widely available materials--that retains its shape after stretching. The properties of this polymer are highly applicable to the preparation of cheaper night-vision lenses that retain focus while imaging at variable distances.

Cameras that function in the dark are common in many fields, including the military, security, firefighting, and wildlife tracking. However, infrared night-vision lenses are typically expensive, and the camera images tend to appear flat. Consequently, there is a need for lenses based on commonly available, cheap materials that are useful for more realistic vision in three dimensions.

The researchers' polymer is based on sulfur and compounds derived from algae and plants. The polymer is easy to prepare using a chemical process called inverse vulcanization: simply mix the constituent compounds together and stir while heating. As a first step, the researchers designed a polymer that is elastic--that is, reverts to its original shape--after being repeatedly restretched by 20%.

"Inverse vulcanization is an ideal synthetic approach for our polymers," explains lead author Professor Junpei Kuwabara. "Squalene and other long unsaturated hydrocarbons help optimize the cross-linking structure and give the polymers a desirable elasticity."

Next, the researchers needed to determine whether lenses constructed from their polymers are at least partially transparent to infrared light, for nighttime imaging. Lens construction was easy: simply pour the polymer into a lens-shaped silicone mold and heat for a few hours. Even a 3.3-millimeter-thick lens transmitted 10% of incoming infrared light.

"The lenses have two wavelength ranges that are infrared-transparent," says senior author Professor Takaki Kanbara. "No lens is completely transparent; 10% transmission is an excellent value for these materials."

Furthermore, the researchers confirmed that the polymer has variable-focus properties. By projecting an image through the lens, and monitoring the resulting image that came through while elongating the lens, much of the transmitted image remained in focus.

"The lens retained 54% of the focus variation, which is sufficient for practical uses," explains Dr. Takashi Fukuda, senior researcher, National Institute of Advanced Industrial Science and Technology (AIST). "The lens also retained its full initial focus after contracting back to its original shape."

The fabrication of conventional infrared night-vision lenses, in a way that allows users to easily change focus from one position to another, is typically difficult. Without a variable-focus capability, details that are pertinent to criminal or research investigations, for example, may be lost. The researchers of this study are overcoming current lens design limitations by using cheap, sustainable materials, and fabrication procecures that any researcher can carry out in their laboratory. Development of new materials in this area may benefit a range of sectors including emergency personnel and environmental researchers

Hydrogen is a versatile fuel that can store and release chemical energy when needed. Hydrogen can be produced in a climate-neutral way by the electrolytic splitting of water into hydrogen and oxygen using solar energy. This can be achieved photo-electrochemically (PEC), and for this approach it is necessary to have low cost photoelectrodes that provide a certain photovoltage under illumination, and remain stable in aqueous electrolytes.

However, here lies the main obstacle; conventional semiconductors corrode very quickly in water. Metal-oxide thin films are much more stable, but still corrode over time. One of the most successful photoanode materials is bismuth vanadate (BiVO4), a complex metal oxide in which photocurrents are already close to the theoretical limit. But the biggest challenge for commercially viable PEC water splitting is now to assess and enhance the stability of photoelectrode materials during their PEC operation.

To this end, a team at the HZB Institute for Solar Fuels led by Prof. Roel van de Krol (HZB) together with groups from the Max Planck Institute for Iron Research, the Helmholtz Institute Erlangen-Nuremberg for Renewable Energy, the University of Freiburg and Imperial College London, have utilised a number of state-of-the-art characterisation methods to understand the corrosion processes of high-quality BiVO4 photo electrodes.

"So far, we could only examine photoelectrodes before and after photoelectrochemical corrosion," says Dr. Ibbi Ahmet, who initiated the study together with Siyuan Zhang from the Max Planck Institute. "It was a bit like reading only the first and last chapters of a book, and not knowing how all the characters died". In a first step to solve this problem, the chemist provided a series of high-purity BiVO4 thin films that were studied in a newly designed flow cell with different electrolytes under standard illumination.

The result is the first operando stability study of high-purity BiVO4 photoanodes during the photoelectrochemical oxygen evolution reaction (OER). Using in-situ plasma mass spectrometry (ICPMS), they were able to determine which elements were dissolved from the surface of the BiVO4 photoanodes during the photoelectrochemical reaction, in real time.

"From these measurements we were able to determine a useful parameter, the stability number (S)," says Ibbi. This stability number is calculated from the ratio between the O2 molecules produced and the number of dissolved metal atoms in the electrolyte and it is in fact a perfect comparable measure of photoelectrode stabilities. The stability of a photoelectrode is high if the splitting of water is proceeding rapidly (in this case the evolution of O2) and few metal atoms enter the electrolyte. This parameter can also be used to determine the change in photoelectrode stability during their lifetime or assess differences in the stability of BiVO4 in various pH-buffered borate, phosphate and citrate (hole scavenger) electrolytes.

This work shows how the stability of photoelectrodes and catalysts can be compared in the future. The authors have continued the collaboration and are now using these valuable techniques and insights to design viable solutions to enhance the stability of BiVO4 photoanodes and enable their use in long term practical applications.

Tsukuba, Japan - Effective regulation of breathing pattern is essential for many different mammalian processes such as energy production, metabolic regulation and even speech. Researchers have recently discovered that the body's production of hydrogen sulfide is important to generate a normal breathing pattern, potentially leading to new treatments for people suffering from breathing disorders such as central sleep apnea.

This result may seem surprising at first given that exposure to high levels of hydrogen sulfide can be toxic to mammalian health. However, hydrogen sulfide is produced in small quantities in the body by an enzyme called cystathionine β-synthase (CBS) and is believed to act as a bioactive gas to regulate different body functions. CBS is located in both the brain and in peripheral systems including arteries, veins and kidneys.

In a study published this month in Communications Biology, researchers from the University of Tsukuba further investigated the role of hydrogen sulfide as a bioactive gas in the body. First they looked at the effect of inhibiting the activity of the CBS enzyme in rats, thereby inhibiting the production of hydrogen sulfide. They found that this resulted in a change in the breathing patterns of the rats from a normal pattern to a gasping pattern. From this, the researchers concluded that the production of hydrogen sulfide allows the regions of the brain that are responsible for controlling breathing patterns to function normally.

Breathing normally requires cells located throughout the body to sense internal levels of oxygen and carbon dioxide and communicate this information to specific brain regions that control breathing rate and pattern. To determine how the different areas of the body are affected by hydrogen sulfide, researchers used different compounds to selectively block the production of hydrogen sulfide in the brain or in peripheral cells.

"Hydrogen sulfide produced by CBS enables neurons located in the brain regions that regulate breathing to communicate," explains Professor Tadachika Koganezawa, the senior researcher on the study. "Without hydrogen sulfide, the centers of the brain responsible for controlling breathing were not able to maintain the neural network to generate normal breathing pattern." The researchers found that these effects were specific to the brain, as inhibition of hydrogen sulfide in peripheral cells had no effect.

By unraveling the effect of hydrogen sulfide in the brain centers that control breathing, researchers can now begin to explore the potential role of hydrogen sulfide in disorders that affect breathing such as central sleep apnea or hyperventilation.

The lack of some genes in the BEC/TCEAL cluster could be related to some alterations associated with the autism spectrum disorder, according to a preclinical study published in the journal Genome Biology, and led by Professor Jordi Garcia Fernàndez, from the Faculty of Biology and the Institute of Biomedicine of the University of Barcelona (IBUB), and researcher Jaime Carvajal, from the Andalusian Centre for Developmental Biology - University Pablo de Olavide (CSIC-UPO).

The study analysed transposon-derived genes that are involved in neural complex functions and that have not been studied before within the context of the autism spectrum disorder and other neurological diseases. The study, carried out with animal models, describes some molecular mechanisms that are determining in the development of the neocortex in humans and other placental mammals.

Among the authors of the study are the experts of the UB Enrique Navas, Bru Cormand, Gemma Marfany, Serena Mirra, Noelia Fernández-Castillo, Ester Antón and Carlos Herrera (also members of IBUB, el IRSJD and el CIBERER), and Eduardo Soriano and Fausto Ulloa (IBUB-CIBERNED-ICREA). The study also counts on the participation of teams from the University Pablo de Olavide, the Centre for Genomic Regulation (CRG), Pompeu Fabra University, the University of Murcia, the Zoological Station Anton Dohrn in Naples (Italy) and Charles University (Czech Republic).

Transposon domestication: how can new functional genes originate?

The BEX/TCEAL cluster is a 14-gene genic family which is not much studied, and it is located in the chromosome X. This genic family codes small proteins from the hub proteinas (connected with many other proteins), which change their configuration according to the molecular context in which they are.

The article states that the genic group BEX/TCEAL resulted from a process known as transposon molecular domestication (genetic mobile elements that can be placed in different areas of the genome). Through this process, a non-functional transposon gen can become a new active element of the genome (domesticated transposon) which develops similarly to the other genes.

Transposons are regarded as a source of evolutionary innovation and adaptation in human beings. "These are genetic components that have no function or are harmful to the host genome. However, in the case of the BEX/TCEAL cluster, these were domesticated by the molecular machinery of the ancestor of placental mammals. That is, they became new genes!", notes Professor Jordi García-Fernández, director of the Department of Genetics, Microbiology and Statistics of the UB and head of the Research Group on Evolution and Development (Evo-Devo).

During the evolutionary process, transposons can lose their ability to jump "due to new mutations, which join the neighbouring effects of the regulator regions where they are, and transform these mobile elements into new genes that have not appeared before during the evolution", notes researcher Enrique Navas-Pérez (UB-IBUB), first author of the article.

According to researcher Jaime J. Carvajal, vice-rector of CABD and head of the Research Group on Molecular Embryology, "such events can have a great importance when setting unique characteristics of mammals. We are looking at the function of a series of genes that can have contributed to the establishment of specific brain properties of placental mammals".

Genes related to autism spectrum disorder

The study states that the BEX3 gene -an element in the BEX/TCEAL cluster-, plays a decisive role in the m-TOR path, a metabolic path related to proliferation and differentiation in many tissues, and specially those in the nervous system. In other studies, other genes from the cluster have been related to neurotrophins (molecules that regulate the neural proliferation in the embryonal nervous system) and p75, a receptor involved in neuronal death.

The conclusions show that the BEX3 gen -and probably other elements in the BEX/TCEA complex- could be implied in several aspects of the autism spectrum disorder and other neurological affectations. Therefore, the mice that were affected by the lack of one of these genes, showed alterations in behaviour which are related to the autism spectrum disorder, apart from showing some anatomical and skeletal changes. "Mice without the BEX3 gene are antisocial, and do not interact with other mice", notes researcher Ángel Carrión, from the Department of Neurosciences of UPO.

"These are new genes, derived from transposons, which are involved in complex neural functions and which have not been studied until now within the context of the autism spectrum disorder and other neurological pathologies", note the researchers.

"Despite being young in evolutionary terms, they could integrate in established biological paths, becoming essential for the right functioning of the animal", notes Cristina Vicente-García, co-author of the article together with Enrique Navas-Pérez and Serena Mirra.

Authors reveal the level of expression of these genes in individuals with autism spectrum is low. As a result, researchers observed a wide range of manifestations in laboratory models, in particular, from autism to compulsive behaviours.

A decisive process in the evolution of placental mammals

Only a few genes in placental mammals are known -and specifically, no gene clusters- that derive from molecular domestication of transposons. For instance, those associated with RAG1/2 proteins, which are key elements of the adaptive immune system of vertebrates, or syncytines, which enabled the development of the complex placenta. "Therefore, we think domestication of these transposons was an important process in the development of the neocortex in the group of placental mammals, to which we belong.

Therefore, the effect that generated the BEX/TCEAL cluster on the ancestral genome conditioned the development of the brain of placental mammals", note the researchers.

"There are still 14 new genes to study -which have not been practically studied until now-, which can be involved in the formation of the complex brain and several manifestations of the autism spectrum. Also, the relation virus-transposons-immune system is very intriguing. For instance, the composition of transposon families of the bat genome is exceptional among mammals, and bats are immune to many viral infections", concludes Jordi Garcia-Fernández.

(Boston)--Genetics and the environment (including psychiatric stress) may contribute to the pace of cellular aging, causing some individuals to have a biological age that exceeds their chronological age.

Researchers from the National Center for PTSD at VA Boston Healthcare System and Boston University School of Medicine (BUSM) now have found that a variant in the klotho gene, a gene previously associated with longevity, interacts with post-traumatic stress disorder (PTSD) to predict accelerated aging in brain tissue. These same researchers had previously shown this effect in living subjects when epigenetic age (biological age) was measured in blood, but this is the first time it has been studied in brain tissue.

Using data from individuals who donated their brains to the VA National PTSD Brain Bank, the researchers were able to examine how genetic variation and PTSD status interacted with each other to predict biological age and gene expression. They found that older adults with PTSD showed evidence of accelerated epigenetic aging in brain tissue if they had the "at risk" (variant) at a particular location in the klotho gene. Follow-up molecular experiments led by BUSM co-authors Cidi Chen, PhD, research associate professor and Carmela Abraham, PhD, professor of biochemistry, showed that this variant regulated the transcription of the klotho gene, suggesting functional consequences of the genetic variant.

Both PTSD and klotho impact inflammation, cardiometabolic conditions and neurodegeneration, including Alzheimer's disease. According to the researchers, better understanding how klotho and PTSD interact and the mechanisms linking both genes and traumatic stress to age-related health conditions is important for the development of novel therapeutics.

"This work allows us to better pinpoint who is at risk for accelerated cellular aging, and possibly, premature disease onset (such as neurodegeneration). This can help to identify the populations at greatest risk so that targeted treatments can be matched to the individuals who need it most. As well, the results point to potential therapeutic targets (klotho) in the development of pharmacological approaches to slow the pace of cellular aging," adds lead author Erika Wolf, PhD, clinical research psychologist for the National Center for PTSD at VA Boston Healthcare System and associate professor of psychiatry at BUSM.

These findings appear online in the journal Neuropsychopharmacology.

Structural damage to any of the nation's ailing bridges can come with a hefty price of billions of dollars in repairs. New bridge designs promise more damage-resistant structures and, consequently, lower restoration costs. But if these designs haven't been implemented in the real world, predicting how they can be damaged and what repair strategies should be implemented remain unresolved.

In a study published in the journal Structure and Infrastructure Engineering, Texas A&M University and the University of Colorado Boulder researchers have conducted a comprehensive damage and repair assessment of a still-to-be-implemented bridge design using a panel of experts from academia and industry. The researchers said the expert feedback method offers a unique and robust technique for evaluating the feasibility of bridge designs that are still at an early research and development phase.

"Bridges, particularly those in high-seismic regions, are vulnerable to damage and will need repairs at some point. But now the question is what kind of repairs should be used for different types and levels of damage, what will be the cost of these repairs and how long will the repairs take -- these are all unknowns for new bridge designs," said Dr. Petros Sideris, assistant professor in the Zachry Department of Civil and Environmental Engineering. "We have answered these questions for a novel bridge design using an approach that is seldomly used in structural engineering."

Most bridges are monolithic systems made of concrete poured over forms that give the bridges their shape. These bridges are strong enough to support their own weight and other loads, such as traffic. However, Sideris said if there is an unexpected occurrence of seismic activity, these structures could crack, and remedying the damage would be exorbitantly expensive.

To overcome these shortcomings, Sideris and his team have developed a new design called a hybrid sliding-rocking bridge. Instead of a monolithic design, these bridges are made of columns containing limb-inspired joints and segments. Hence, in the event of an earthquake, the joints allow some of the energy from the ground motion to diffuse while the segments move slightly, sliding over one another rather than bending or cracking. Despite the overall appeal of the hybrid sliding-rocking bridge design, little is known about how the bridges will behave in real-world situations.

"To find the correct repair strategy, we need to know what the damages look like," said Sideris. "Our bridge design is relatively new and so there is little scientific literature that we could refer to. And so, we took an unconventional approach to fill our gap in knowledge by recruiting a panel of experts in bridge damage and repair."

For their study, Sideris, Dr. Abbie Liel, professor at the University of Colorado, Boulder, and their team recruited a panel of eight experts from industry and academia to determine the damage states in experimentally tested hybrid sliding-rocking segment designed columns. Based on their evaluations of the observed damage, the panel provided repair strategies and estimated costs for repair. The researchers then used that information to fix the broken columns, retested the columns under the same initial damage-causing conditions and compared the repaired column's behavior to that of the original column through computational investigations.

The panel found that columns built with their design sustained less damage overall compared to bridges built with conventional designs. In fact, the columns showed very little damage even when subject to motions reminiscent of a powerful once-in-a-few-thousand-years earthquake. Furthermore, the damage could be repaired relatively quickly with grout and carbon fibers, suggesting that no special strategy was required for restoration.

"Fixing bridges is a slow process and costs a significant amount of money, which then indirectly affects the community," said Sideris. "Novel bridge designs that may have a bigger initial cost for construction can be more beneficial in the long run because they are sturdier. The money saved can then be used for helping the community rather than repairing infrastructure."

HOUSTON - (Oct. 26, 2020) - Engineers at Rice University and Texas A&M University have found a 2D material that could make computers faster and more energy-efficient.

Their material is a derivative of perovskite -- a crystal with a distinctive structure -- that has the surprising ability to enable the valleytronics phenomenon touted as a possible platform for information processing and storage.

The lab of materials scientist Jun Lou of Rice's Brown School of Engineering synthesized a layered compound of cesium, bismuth and iodine that is adept at storing the valley states of electrons, but only in the structure's odd layers.

These bits can be set with polarized light, and the even layers appear to protect the odd ones from the kind of field interference that bedevils other perovskites, according to the researchers.

Best of all, the material appears to be scalable.

"This is not a new material, but we figured out a way to make it without solution processing or exfoliating it from bulk," Lou said. "What's novel is that we can produce it (via chemical vapor deposition) in a few layers, and all the way down to a monolayer. That enabled us to probe its nonlinear optical properties."

The discovery is detailed in Advanced Materials.

Valleytronics are a cousin to spintronics, in which memory bits are defined by an electron's quantum spin state. In valleytronics, electrons have degrees of freedom in the multiple momentum states -- or valleys -- they occupy. These states can be read as bits.

"In a transistor, if you put an electron there, it represents a state, and if you take it out, that represents another state," said co-principal investigator Hanyu Zhu of Rice. "In valleytronics, the electrons are always present, and are in either of two different quantum wavefunctions with opposite momenta. These two wavefunctions interact with different light polarization, so the momentum state can be resolved optically."

A close look at the inorganic, lead-free material through an electron microscope showed molecules in the odd layer are asymmetric. "That lack of symmetry is missing in the even layers -- that's how we differentiate between them -- and it gives rise to the properties we see," Lou said. "That's just the nature of this crystal structure."

The lab tested the material with up to 11 layers and found a lack of transparency doesn't seem to affect how well light triggered a response. "Even a thicker material behaves like it's still a single layer," Lou said. "That's quite important."

"Thicker 2D transition metal dichalcogenides lose unique properties like valleytronics," he said. "All the behaviors are gone. That's not the case for this material."

Lou said calculations by co-principal investigator Xiaofeng Qian of Texas A&M University provided the necessary theoretical evidence.

"The valley polarization observed in both thin and thick layers is largely due to the weak interlayer electronic coupling, a unique feature of this perovskite derivative compared to other 2D materials when stacked together," Qian said. "It also leads to persistent nonlinear optical responses in thicker samples."

The material also seems less susceptible to environmental degradation, a common problem for hybrid perovskites developed for solar energy. "This material won't give you very high conversion efficiency, but think of it like an all-around athlete in the Olympic Games," said lead author and Rice postdoctoral fellow Jia Liang. "It may not be the best in each category, but if you consider its different aspects together, it will stand out," he said.

The researchers suggested the already strong light-matter interaction they observed could be enhanced by further engineering the material's band gap.

"I think it's a breakthrough for using this type of material in information processing," Lou said. "We're really hoping this is the starting point."

Seabirds arrived on the remote cluster of islands in the South Atlantic known as the Falkland Islands 5,000 years ago. Their arrival occurred at the same time as the region cooled.

Coincidence?

Probably not, according to experts like Dulcinea Groff, whose research interests include paleoecology, paleoclimate, conservation and environmental change. Instead, their arrival suggests that the Falkland Islands were a cold-climate refuge for seabirds. Today, a warming Southern Ocean calls into question the long-term viability of the Falkland Islands as a habitat for seabirds whom Groff calls the “canaries in the coalmine of the ocean and land where they nest” because of their sensitivity to climate change.

Groff and her colleagues set out to discover how seabirds responded to climate change thousands of years ago because the past provides a window into how seabirds might respond to a changing climate in the future. The team's examination of a 14,000-year record, derived from peat?a natural archive of information about past environments?reveals that an ecosystem shift occurred following seabird establishment 5,000 years ago, as marine-derived nutrients from guano (accumulated bird excrement) facilitated the establishment of tussac (a type of grass), peat productivity, and increased fire. The results of the study have been published today in Science Advances in an article ( https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.abb2788) called, "Seabird establishment during regional cooling drove a terrestrial ecosystem shift 5000 years ago." (DOI: 10.1126/sciadv.abb2788)

"Our 14,000-year record raises a very troubling question about where seabirds will go as the climate continues to warm because the seabirds at Surf Bay established when the climate was cooler," says Groff, who is currently a Research Fellow in Lehigh's Department of Earth and Environmental Sciences. (https://ees.cas.lehigh.edu/) This work was part of her dissertation (https://digitalcommons.library.umaine.edu/etd/2929/) at the University of Maine. "A couple centuries of introduced livestock grazing has severely damaged tussac grasslands, which are critical wildlife habitat. We learned just how important the nutrients in seabird poop are for the ongoing efforts to restore and conserve their grassland habitat."

Scientists are able to learn about the past by analyzing peat because it preserves the remains of plants and animals as it accumulates or builds up over thousands of years. Groff and her colleagues examined pollen made by the plants, charcoal left over from grassland fires, and chemical indicators associated with seabirds being present, all derived from peat samples. The peat profile allowed them to determine the order of events with the seabirds and their breeding habitat: the tussac grasslands.

"Our study is unique because it documents a direct linkage across ocean and land ecosystems between top predators of the oceans -the seabirds- and island plant communities," says Groff. "The abrupt ecosystem shift happened within a matter of a few decades and suggests that as the climate continues to warm, it's critical to think about where seabirds will go in the future and plan to protect those places. This is also relevant toward efforts to restore the tussac grasslands because as the climate warms, seabirds may find and occupy more suitable environments elsewhere, and we should expect that the coastal grasslands will respond to the loss in nutrients from seabird guano."

A UCLA-led review of nine years of social media posts with the hashtag #BCSM suggests that Twitter can be a useful resource not only for patients, but also for physicians and researchers.

The hashtag -- an initialism for "breast cancer social media" -- first appeared on Twitter in 2011. Created by two cancer survivors, it was used to curate a weekly informational chat for people with breast cancer. Dr. Deanna Attai became one of the group's moderators a few weeks later.

"We physicians have a lot to learn from the online patient communities," said Attai, an assistant clinical professor of surgery at the David Geffen School of Medicine at UCLA, and the lead author of the study. "Tapping into this gold mine of experience will ensure that when we design research studies, we are asking questions that are actually relevant and important to patients."

The research found that, between Jan. 1, 2011, and Jan. 1, 2020, #BCSM was used more than 830,000 times by more than 75,000 unique Twitter accounts, generating 4 billion impressions. The hashtag was used 145,600 times in 2019 alone, an increase of 424% from 2011 when it appeared 27,700 times.

The study, published today in the Journal of Patient-Centered Research and Reviews, is intended to help researchers understand the impact of the community that grew up around the Twitter chat. It reveals that, paralleling the rise of social media in everyday life, the growing popularity of #BCSM demonstrated that an increasing number of people with breast cancer are turning to online communities for support and education.

#BCSM has evolved into much more than a hook for weekly virtual meetings. The hashtag made it easy for people with breast cancer to find support and useful content -- and for their family members, patient advocates, physicians, researchers, journalists and others to source good information.

"The #BCSM online community has experienced tremendous growth since its inception because it has helped fulfill a need among patients who were searching for information and support on the platform," said Attai, who is also a member of the UCLA Jonsson Comprehensive Cancer Center. "But it has also helped us physicians gain insight into the patient perspective and has given us a better understanding of their many issues. We often see patients in a much different setting. Compared to our exam room interactions, online is a more raw, unvarnished look into what patients are really going through."

The platform also gave professionals the opportunity to, in real time, correct misconceptions, provide guidance to people with breast cancer and steer them toward credible resources, Attai said.

To compile data on the use of #BCSM, the researchers used Symplur, a health care-focused analytics program commonly used to study trends on Twitter.

The research also found that number of health care professionals, including doctors, who use the hashtag has grown significantly, from 96 by the end of 2011 to more than 3,000 in 2019.

The study notes that the inclusive nature of the #BCSM hashtag -- it's not restricted by gender or by people's stage of diagnosis -- has probably contributed to its popularity. But its breadth might also limit how sustainable the online community will be, because as cancer therapy continues to become more personalized, people may increasingly seek out support groups that are more closely aligned with their own clinical situations.

MADISON, Wis. -- Scientists at the University of Wisconsin-Madison have discovered a way to control the growth of twisting, microscopic spirals of materials just one atom thick.

The continuously twisting stacks of two-dimensional materials built by a team led by UW-Madison chemistry Professor Song Jin create new properties that scientists can exploit to study quantum physics on the nanoscale. The researchers published their work today in the journal Science.

"This is the current frontier of 2D material research. In the last few years, scientists have realized that when you make a small twist between atomic layers -- usually a few degrees -- you create very interesting physical properties, such as unconventional superconductivity. For example, the twisted material loses its electrical resistance completely at the low temperature," says Jin. "Researchers consider these 2D-quantum materials, and call such work 'twistronics.'"

Yuzhou Zhao, a graduate student and first author of the study, says the standard practice for making twisting two-dimensional structures has been mechanically stacking two sheets of the thin materials on top of each other and carefully controlling the twist angle between them by hand. But when researchers grow these 2D materials directly, they cannot control the twist angle because the interactions between the layers are very weak.

"Imagine making a stack of continuously twisting playing cards. If you have nimble fingers, you could twist the cards, but our challenge is how to make the atomic layers twist in a controllable way by themselves at the nanoscale," Jin says.

Jin's team found out how to control these twisting nanoscale structures' growth by thinking outside the flat space of Euclidean geometry.

Euclidean geometry forms the mathematic basis of the world we are familiar with. It allows us to think about the world in flat planes, straight lines and right angles. In contrast, non-Euclidean geometry describes curved spaces in which lines are curved and the sum of the angles in a square is not 360 degrees. Scientific theories that explain the space-time continuum, like Einstein's general relativity, use non-Euclidean geometry as bedrock. Thinking about crystal structures outside Euclidean geometry, Jin says, opens up intriguing new possibilities.

Zhao and Jin created twisted spirals by taking advantage of a type of imperfection in growing crystals called screw dislocations. Jin has studied such dislocation-driven crystal growth for years and had used it to explain, for example, the growth of nanowire trees. In 2D materials, the dislocations provide a step up for following layers of the structure as it spirals like a parking ramp with all layers throughout the stack connected, aligning the orientation of every layer.

Then, in order to grow a non-Euclidean spiral structure and make the spirals twist, Jin's team changed the foundation their spirals grew from. Instead of growing crystals on a flat plane, Zhao placed a nanoparticle, like a particle of silicon oxide, under the spiral's center. During the growth process, the particle disrupts the flat surface and creates a curved foundation for the 2D crystal to grow on.

What the team found is that instead of an aligned spiral where the edge of each layer lies parallel to the previous layer, the 2D crystal forms a continuously twisting, multilayer spiral that twists predictably from one layer to the next. The angle of the interlayer twist arises from a mismatch between the flat (Euclidean) 2D crystals and the curved (non-Euclidean) surfaces they grow on.

Zhao calls the pattern in which the spiral structure grows directly over the nanoparticle, creating a cone-shaped base, a "fastened spiral." When the structure grows over an off-center nanoparticle, like a house built on the side of a mountain, it's an "unfastened spiral" pattern. Zhao developed a simple mathematic model to predict the twist angles of spirals, based on the geometric shape of the curved surface, and his modelled spiral shapes match well with the grown structures.

After the initial discovery, UW-Madison material science and engineering professor Paul Voyles and his student Chenyu Zhang studied the spirals under an electron microscope to confirm the alignment of the atoms in these twisted spirals. Their images showed that atoms in neighboring twisted layers form an expected overlapping interference pattern called a moiré pattern, which also gives fine layered silk clothing its sheen and ripple. Emeritus chemistry professor John Wright and his lab conducted preliminary studies suggesting the potential for unusual optical properties of the twisting spirals.

The researchers used transition metal dichalcogenides as the layers for the twisting spirals, but the concept doesn't depend on specific materials, as long as they are 2D materials.

"We now can follow a rational model rooted in mathematics to create a stack of these 2D layers with a controllable twist angle between every layer, and they're continuous," Zhao says.

Direct synthesis of twisting 2D materials will enable the studies of novel quantum physics in these 2D "twistronic" materials, which Jin and his collaborators are pursuing in earnest.

"When you see everything matches perfectly with a simple math model and you think, 'Wow, this is really working out,' that kind of joy is why we work on research -- that 'eureka' moment that you realize you're now learning something nobody else has understood before," Jin says.

Virologists at Institut national de la recherche scientifique (INRS) have identified a critical role played by a cellular protein in the progression of Hepatitis C virus infection, paving the way for more effective treatment. No vaccine currently exists for Hepatitis C virus infection, which affects more than 130 million people worldwide and nearly 250,000 Canadians. Antivirals exist but are expensive and not readily available in developing countries, where the disease is most prevalent.

Professor Terence Ndonyi Bukong and his team of virologists, in partnership with Professor Patrick Labonté, discovered this potential therapeutic target. They unveiled that the cellular protein RTN3 was involved in mediating an important pathway essential in Hepatitis C virus disease development, and progression. This promising discovery could lead to better treatments for the disease, which kills approximately 500,000 people annually.

Master of disguise

Normally, the immune system needs to recognize a virus to attack it and prevent infection. The Hepatitis C virus, however, is a master of disguise. It moves around, undetected, in exosomes, which are cell-released microvesicles vesicles that normally function in cellular communication, transport, and cellular waste disposal. This novel research revealed that the Hepatitis C viruses interact with a key area of the RTN3 protein utilizing it to insert their viral RNA into exosomes.

"We are the first researchers to demonstrate the exosomal role that this protein plays in hepatitis C pathogenesis," said Dr. Bukong, who led the study published in the journal PLOS One. "By identifying the areas of the protein that lead to the formation of an infectious exosome, we can now look for distinctive molecules that block the interaction with the viral RNA." He went on to say, "This would prevent the viral RNA from being able to enter exosomes and hide from the body's immune system."

The discovery of this interaction between the virus and the RTN3 protein opens the door to more research on other viruses that use exosomes to evade detection. "For example, studies have shown that HIV, Zika, and Hepatitis B viruses also hide inside exosomes. This disguise creates a problem for the optimal function of vaccines because even if antibodies are developed, they are unable to block viral infection or transmission," Dr. Bukong explained. "If the RTN3 protein also plays an important role in these other illnesses, it could help us make more effective treatments, and, potentially, more effective vaccines."

University of Kent research has found that when individuals feel that a system or authority is unresponsive to their demands, they are more likely to legitimise hacker activity at an organisation's expense.

Individuals are more likely to experience anger when they believe that systems or authorities have overlooked pursuing justice on their behalf or listening to their demands. In turn, the study found that if the systems or authorities in question were a victim of hacking, individuals would be more likely to legitimise the hackers' disruptive actions as a way to manifest their own anger against the organisation.

With more organisations at risk to cyber security breaches, and more elements of individuals' social lives taking place online, this research is timely in highlighting how hackers are perceived by individuals seeking justice.

The research, led by Maria Heering and Dr Giovanni Travaglino at the University of Kent's School of Psychology, was carried out with British undergraduate students and participants on academic survey crowdsourcer, Prolific Academic. The participants were presented with fictional scenarios of unfair treatment from authorities, with complaints either dismissed or pursued, before they were told that hackers had defaced the authorities' websites. Participants were then asked to indicate how much they disagreed or agreed with the hackers' actions. These hackers were predominantly supported by participants perceiving them as a way to 'get back at' the systems who do not listen to their demands.

Maria Heering said: 'When individuals perceive a system as unjust, they are motivated to participate in political protest and collective action to promote social change. However, if they believe they will not have voice, they will legitimise groups and individuals who disrupt the system on their behalf. While this study explored individuals' feelings of anger, there is certainly more to be explored in this research area. For example, there might be important differences between the psychological determinations of individuals' support for humorous, relatively harmless forms of hacking, and more serious and dangerous ones.'