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Tiny, symbiotic fungi play an outsized role in helping plants survive stresses like drought and extreme temperatures, which could help feed a planet experiencing climate change, report scientists at Washington State University.

Recently published in the journal Functional Ecology, the discovery by plant-microbe biologist Stephanie Porter and plant pathologist Maren Friesen sheds light on how microbe partners can help sustainably grow a wide variety of crops.

Tiny partners in plant survival

While some microscopic fungi and bacteria cause disease, others live in harmony with plants, collecting water and nutrients in exchange for carbohydrates, or changing plants' internal and external environment in ways that help plants grow.

These benefits help plants tolerate stresses that come from their environment. Dubbed abiotic stresses, challenges such as drought, extreme temperatures, and poor, toxic, or saline soils are among the leading causes of crop loss and decreasing farm productivity.

"Plants' abilities to tolerate stress are impacted by the bacteria and fungi that live on or inside them and make up the plant microbiome," said Porter, assistant professor in the School of Biological Sciences. "Just like how microbes in our digestive system help keep us healthy, microbes play an incredibly important role in plant health."

Setting out to measure how beneficial microbes affect plants under both normal conditions and stress, Porter and Friesen reviewed 89 research experiments ranging from common Northwest food crops to wild species.

Working with colleagues at Michigan State University and WSU, they compared five different classes of symbiotic bacteria and fungi that live on, in, and around plant roots, under stresses that included fungal diseases, grazing by animals and microscopic worms, heavy metal contamination, and drought, cold, and saline soils. Then, they tallied the effect on plant growth, biomass and yield.

Results showed that while beneficial bacteria are more helpful in normal conditions, symbiotic fungi provide added benefits during crises.

"Stress makes these fungi even more important to plants, which we think is really interesting," said Friesen, assistant professor in the Department of Plant Pathology.

Particularly beneficial were arbuscular mycorrhizal fungi, which colonize plant roots, provide water, and enhance uptake of nitrogen, phosphorus, and other micronutrients in the soil.

"Should growers want to foster the plant microbiome for stress resistance, our study suggests they should really focus on fungi," Porter said. "These beneficial microbes could be the key to helping us grow more food in the coming decades."

A greener solution to stress

With earth's population predicted to top 9 billion by 2050, scientists predict that current crop yields will need to double.

"As we expand where we grow crops, we're using marginal areas that are more stressful for plants," Porter said. "And as our climate changes, that creates stress for plants.

"Maren and I wanted to be forward-looking," she added. "We wanted to find evidence of how we can best use beneficial microbes to mitigate the stresses that we know are coming."

Microbes offer a more sustainable tool for stress tolerance than applying hormones or chemicals, noted Friesen.

"Farmers are now having challenges with pathogens no longer responding to chemical treatments," she said. "There's already a lot of interest in scientific and industry circles in identifying and harnessing microbial solutions to agricultural problems. This study gives us ideas about where to look."

People who cycle to work have a lower risk of dying, a New Zealand study has found.

The study, by researchers from the University of Otago, Wellington, the University of Melbourne and the University of Auckland, has just been published in the International Journal of Epidemiology.

Lead researcher Dr Caroline Shaw, from the Department of Public Health at the University of Otago, Wellington, says people who cycled to work had a 13 per cent reduction in mortality during the study, likely as a result of the health benefits of physical activity. There was no reduction in mortality for those who walked or took public transport to work.

The researchers used data from the New Zealand Census-Mortality Study, which links census and mortality records, to do follow-up studies of the population for three to five years following the 1996, 2001 and 2006 censuses, when respondents were asked: 'On X date (census day), what was the one main way you travelled to work - that is, the one you used for the greatest distance?'

Dr Shaw says the study, which analysed data from 3.5 million New Zealanders, is one of the largest ever cohort studies to examine the association between mode of travel to work and mortality outcomes.

"We studied 80 per cent of the working-age population of New Zealand over a 15-year period, so it is highly representative."

Dr Shaw says increasing 'active transport' is being promoted as a way of addressing health and environmental issues, but the association between different modes of transport, such as cycling, walking and public transport, and health outcomes has remained unclear.

The study found more than 80 per cent of people in New Zealand travelled to work by car on census day, with only five per cent walking and three per cent cycling.

"There were gender differences in mode of travel to work, with two per cent of women cycling compared with four per cent of men, but more women walking or jogging (seven per cent), compared with men (five per cent). A higher proportion of younger people cycled, walked or took public transport compared with older people."

Dr Shaw says the census data provided no details about the physical intensity of the commute, so those who lived in the inner city and walked 200 metres to work were in the same category as those who walked briskly up and down a hill for 30 minutes to get to and from work.

"We saw no increase in road traffic injury deaths associated with walking and cycling, although the New Zealand transport system at the time of these studies was heavily car-dominated and roads seldom made allowances for pedestrians and cyclists."

Dr Shaw says the findings lend support for initiatives to increase the number of people commuting to work by bike.

"Increasing cycling for commuting to work in a country with low levels of cycling like New Zealand will require policies directed at both transport and urban planning, such as increasing housing density and implementing cycling networks."

While the study found no association between walking or taking public transport to work and a reduction in mortality, Dr Shaw says there are other reasons to promote these modes of transport.

"Walking to work has physical-activity-related health benefits other than mortality reduction - including the prevention of cardiovascular disease and diabetes - and taking public transport has the benefit of emitting less carbon."

Osaka, Japan - Serine racemase (SRR) is a multifunctional enzyme that carries out several different reactions in human cells, including the conversion of L-serine into pyruvate. Despite already being well characterized, a team of researchers led by Osaka University have discovered an important new role for SRR in cancer metabolism, exposing the metabolic pathway as a viable target for novel anti-cancer therapies.

Researchers have long known that cancer cells display an altered metabolism that favors their growth, survival, and metastasis. Colorectal cancer is one of the most common cancers worldwide but is particularly prevalent in developed countries where it is associated with certain dietary factors and a sedentary lifestyle. One of the hallmarks of colorectal cancer cells is an altered metabolism that is not associated with tumor-causing mutations.

"Pyruvate is known to have an important role in cancer metabolism," explains lead author of the study Dr Kenji Ohshima. "However, no one had previously studied how pyruvate produced by SRR is involved in cancer metabolism."

Therefore, the researchers set out to examine what role, if any, SRR plays in the development of colorectal cancer.

In a study published this month in Nature Metabolism, the researchers showed that SRR is much more abundant in colorectal cancer cells than in the surrounding tissues, and that cancer cell lines with higher levels of SRR divide at a much faster rate.

Says Dr Ohshima, "This was a really exciting discovery because it showed that SRR is involved in colorectal cancer cell proliferation. When we then looked more closely at the pathway as a whole, we found that pyruvate levels were decreased in a slow-growing SRR mutant colorectal cancer cell line, suggesting that the pyruvate produced by SRR enhances the proliferation of colorectal cancer cells. This result confirmed that the metabolic pathway is integral to the progression of colorectal cancer."

Given the obvious importance of SRR, the researchers then decided to test whether disruption of the metabolic pathway could prevent the progression of colorectal cancer. Astonishingly, not only did inhibition of SRR halt the growth of colorectal tumors in mice, it also improved the efficacy of currently available drugs used to treat colorectal cancer, causing a significant reduction in tumor size.

"There is still work to be done to confirm that our results translate into human cancer systems," explains senior author of the study Dr Eiichi Morii. "However, based on these preliminary results, we expect that future strategies targeting SRR will provide effective new therapies for the treatment of colorectal cancer."

Published in Psychological Medicine, the research used fMRI scans to examine the brain activity of 13 people with a diagnosis of psychosis under the influence of a single dose of CBD or placebo and 16 controls whilst they were undertaking a memory task. The researchers showed that, during the task, there was a different pattern of activity in the prefrontal and mediotemporal brain areas of people with psychosis under placebo compared to the activity seen in those without psychosis. When those with psychosis were given one dose of CBD, the activation in these brain areas became more like the activation seen in controls.

Senior author on the study, Professor Sagnik Bhattacharyya, from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London said: 'Our study provides important insight into which areas of the brain CBD targets. It is the first time research has scanned the brains of people with a diagnosis of psychosis who have taken CBD and, although the sample is small, the results are compelling in that they demonstrate that CBD influences those very areas of the brain that have been shown to have unusual activity in people with psychosis.'

CBD is one of over 100 chemical compounds known as cannabinoids that are found in the cannabis plant. There has been recent interest in the use of cannabidiol (CBD) as an alternative to current antipsychotic medicines as it could prove to be more tolerable generally and more effective for a subset of people who do not respond to available antipsychotics. Its use has been associated with a decrease in symptoms of psychosis and changes in brain activity during verbal memory tasks in patients at high risk of psychosis.

The study also showed that activity in the striatum and the activity in hippocampus was more co-ordinated in people with psychosis, indicating there was a greater functional connectivity between these two areas in this group compared to controls. After one dose of CBD this functional connectivity was reduced in people with psychosis and became more similar to that seen in the controls. Those people with psychosis continued on their existing antipsychotic treatment throughout the study.

The results indicate that CBD has a moderating effect on the altered pattern of brain activity in the prefrontal, mediotemporal and striatal areas in people with psychosis. The study also showed that psychotic symptoms did show a decreasing trend after the dose of CBD but researchers highlighted that no definitive conclusions could be drawn about this effect as the study did not look at sustained use of CBD and the sample size was small.

Professor Bhattacharyya added: 'This study provides important insight into the brain mechanisms behind the antipsychotic effects of CBD. It gives confidence in the antipsychotic potential of CBD by demonstrating that it targets the function of brain regions implicated in psychosis and indicating that even a single dose may ameliorate some of the brain function alterations that may underlie psychosis. The finding that psychotic symptoms may show a trend towards improvement in this group even after one dose of CBD is encouraging, but requires a larger scale clinical trial to investigate if the effects would continue with longer term treatment. The results form an important part of the picture that scientific research is building on the effects of CBD and will help support the case for further clinical trials on the use of CBD in different stages of psychosis as well other neuropsychiatric diseases such as Parkinson's disease where a proportion of patients may also experience psychotic symptoms.'

A study conducted out of The University of Georgia delved into the comparative yields of sweet pepper varieties produced under organic farming conditions.

George Boyhan, Cecilia McGregor, Suzanne O'Connell, Johannah Biang, and David Berle completed a replicated, randomized experiment involving 13 pepper varieties produced on land managed organically for the 6 previous years.

The results of the evaluation are in the article "A Comparison of 13 Sweet Pepper Varieties under an Organic Farming System" published in the open access journal HortTechnology, by the American Society for Horticultural Science.

With the growth of the organic market, there is interest in identifying and developing fruits and vegetables that are adapted to organic farms. Sweet peppers are no exception. They possess a measurable popularity and economic importance in the Southeastern region of the United States. In 2018, the U.S. produced almost 42,000 acres of bell peppers, with four-fifths of this production aimed at the fresh market. Yet there has been a dearth of information on how different pepper varieties perform under organic conditions.

The researchers, in an effort to fill that information void, were mainly interested in quantifying total yield, graded yield, and early yield of the peppers in a hot, humid climate. Characteristics that would prove desirable in organic production include resistance to biotic and abiotic stressors, including diseases, weeds, and insects, as well as nutrient use efficiency and high yields with good fruit quality.

The sweet pepper varieties included in the study were (referred to here by their common names) Aristotle X3R, Blitz, California Wonder, Flavorburst, Gourmet, Gridiron, Islander, Jupiter, King Arthur, PS 09979325 X10R, Red Knight X3R, Sweet Chocolate, and Touchdown.

Twelve of the 13 varieties in this trial were typical bell peppers. Sweet Chocolate was the exception, as a small sweet pepper that is dark brown at maturity. Small sweet peppers have recently gained in popularity; however, they are usually yellow, orange, or red at maturity.

Variety choices were based on seed catalog descriptions promoting appropriateness for summer/fall production, disease resistance, and popularity among growers. Several of these entries, according to their developers, have some level of resistance to bacterial leaf spot, a prominent disease of bell peppers that may reduce marketable yield.

Pepper seedlings were planted in midsummer and harvested in September and October across two years. Organic fertilizers were mixed into the soil before the raised beds with drip tape and were covered with white over black plastic mulch. Differences in crop yield and days to harvest after transplanting were compared while pest and disease issues were monitored. Pest management decisions were based on weekly scouting, and treatment actions were based on organic pest management guidelines.

O'Connell adds, "Overall, the results were very encouraging since many varieties included in the study surpassed the average U.S. production rate of 1,341 boxes per acre. In addition, because the yield results are broken down into different categories such as size and earliness, growers can further strategize about which varieties fulfill their most important markets."

Stand-out varieties included Aristotle X3R and Gridiron for fancy and early yield as well as Sweet Chocolate for early yield.

Typically, organic produce sells for prices 10% to 100% higher than the conventional equivalent, with colored peppers being on the higher end of the spectrum. Although organic production is generally more expensive than conventional production, the researchers determined that organic bell peppers appear to be a viable endeavor.

O'Connell shared that the results of the study pointed to a number of valuable future research areas including: 1) How do hot temperatures affect pepper pollination, diseases and pests, and what are ways to manage these challenges? 2) Are consumers interested in small-fruited peppers? 3) How can peppers be incorporated into organic crop rotation plans to maintain profitability over time?

An international research team which includes specialists from ITMO University has conducted a series of experiments with the goal of studying the immune system and identifying the genes and proteins involved in the response to certain harmful bacteria. The scientists found that "turning off" a gene responsible for the production of the protein Beclin 1, or the gene that produces the FIP200 protein, resulted in the test animals becoming nearly completely immune to the infectious disease listeriosis. The results of this research have been published in Nature Microbiology.

The way the immune system functions is an extremely complex process and the mechanics of it have still not been fully understood by scientists. Which proteins are responsible for the immune response? Can an organism be made genetically impervious to all, or at least some malignant bacteria? Biologists and geneticists all over the world seek answers to these questions.

In order to understand how the immune system works, scientists conduct experiments and study mice populations in which the animals possess certain non-functioning genes as a result of prolonged targeted cross-breeding. When this approach, known to scientists as "gene knockout", results in changes to the way an animal's immune system operates, it means that the gene has a direct effect on the immune response.

An international research team has conducted a study of mice that have had two genes "knocked out", namely the ones responsible for the production of two proteins: Beclin 1 and FIP200. Notably, the knockout was made not to the entire organism, but to the myeloid cells (a sub-type of immune cells) of the mice. These proteins are involved in the process of autophagy, which is the degradation of molecules and organelles by the cells. It was found that this knockout made the animals almost completely impervious to the Listeria monocytogenes bacteria - the cause of the dangerous disease listeriosis. The disease affects the nervous system and, if left untreated, may be fatal.

"Listeria monocytogenes is a bacterium that divides within the cell," explains Konstantin Zaitsev, a co-author of the study, PhD student, and staff member of ITMO University's Computer Technologies Lab. "We've found that disabling the genes responsible for Beclin 1 or FIP200 allows the mice to fight off the infection and recover nicely."

Such a result has to do with the fact that the immune system of a mouse with knocked-out genes is activated permanently, as opposed to regular mice whose immune systems are only activated by external factors.

Macrophages, a type of white blood cells, are therefore constantly excited, which allows them to instantly take action when Listeria monocytogenes is introduced to the organism.

At first glance, gene editing doesn't seem to have any fatal effect on the test animals' lives: they grow, develop, feed, and procreate as normal. But that doesn't mean that turning off their genes leaves the mice unscathed. As the experiments showed, other infections, such as influenza, still affect the test mice at the same rate as regular mice. It should also be noted that, while the test animals developed nearly in the same manner as their regular counterparts, they were vulnerable to their own immune system: the scientists registered signs of chronic inflammation in some of the mice's organs.

"A permanently active immune system is a double-edged sword," explains Zaitsev. "There is a lot of background inflammation going on. It's no accident that the immune system is at rest most of the time. We don't want it reacting to the many processes that take place within the organism."

Nevertheless, the researchers' study provides a great deal of analytical material in regards to the effects of proteins Beclin 1 and FIP200 on the immune response to pathogenic microorganisms.

AUSTIN, Texas -- A multidisciplinary team of engineers and scientists has developed a new class of filtration membranes for a variety of applications, from water purification to small-molecule separations to contaminant-removal processes, that are faster to produce and higher performing than current technology. This could reduce energy consumption, operational costs and production time in industrial separations.

Led by Manish Kumar, associate professor in the Cockrell School of Engineering at The University of Texas at Austin, the research team describes their new high-performance membranes in a recent issue of Nature Materials.

The team's new filtration membranes demonstrate higher density of pores than that of commercial membranes and can be produced much faster -- in two hours, versus the several-day process currently used. Until now, integrating protein-based membranes into current technology used for industrial separations has been challenging because of the amount of time needed to create these membranes and the low density of proteins in resulting membranes.

This comprehensive and collaborative research effort brought together engineers, physicists, biologists and chemists from UT Austin, Penn State University, University of Kentucky, University of Notre Dame and the company Applied Biomimetic. The work presents the first end-to-end synthesis of a true protein-based separation membrane with pores between half a nanometer and 1.5 nanometers in size. A nanometer is just a few times the size of a water molecule and a hundred thousand times smaller than the width of a human hair.

The membranes created by the team are biomimetic, meaning they mimic systems or elements of nature, and imitate those that naturally occur in cell membranes for transporting water and nutrients. They recently published another paper highlighting the inspiration for their method. High-density packing of these protein channels into polymer sheets forms protein pores within the membrane, similar to those seen in human eye lenses, but within a nonbiological polymer environment.

Three different biomimetic membranes were fabricated by the team and demonstrated a sharp, unique and tunable selectivity with three different pore sizes of membrane protein channels. The methods described can be adapted with the insertion of protein channels of different pore sizes or chemistries into polymer matrices to conduct specifically designed separations.

"In the past, attempts to make biomimetic membranes fell far short of the promise of these materials, demonstrating only two to three times improvement in productivity," said Yu-Ming Tu, a UT Austin chemical engineering doctoral student and lead on the project. "Our work shows a surprising 20 to 1,000 times improvement in productivity over the commercial membranes. At the same time, we can achieve similar or better separation of small molecules, like sugars and amino acids, from larger molecules, like antibiotics, proteins and viruses."

This high productivity was made possible by the very high density of pore proteins. Approximately 45 trillion proteins can fit onto the membrane, if it were the size of a U.S. quarter; the membranes created were 10-20 times larger in area. This pore density is 10 to 100 times higher than conventional filtration membranes with similar nano-sized pores. Additionally, all the pores in these membranes are exactly the same size and shape, allowing them to better retain molecules of desired sizes.

"This is the first time that the promise of biomimetic membranes involving membrane proteins has been translated from the molecular scale to high performance at the membrane scale," Kumar said. "For so long, engineers and scientists have been trying to find solutions to problems only to find out nature has already done it and done it better. The next steps are to see if we can fabricate even larger membranes and to test whether they can be packaged into flat sheet and spiral-wound-type modules like the ones common in industry."

When chemists or engineers want to make a new type of material, they head to the laboratory and start "cooking." Much like trying to improve upon a food recipe, the process involves trying new chemical ingredients or adjusting cooking times and temperatures. But what if instead of relying on a time-consuming process without guarantees of success, scientists could simply "snap" different chemical "pieces" together to make something new?

In a study published in the Journal of the American Chemical Society, a team of researchers from the University of Pennsylvania, University of Nebraska-Lincoln (UNL), Colorado School of Mines, and Harbin Institute of Technology, in China, describes a new approach for synthesizing organic "Legos" that can be easily connected to make new materials. This framework creates structures that are lightweight, porous, and quick to synthesize and easily modified to create new materials with unique properties.

The study focuses on a relatively new structure known as covalent organic frameworks, or COFs. COFs are 2D and 3D organic solids held together with strong, covalent bonds. COFs have crystalline structures made of light elements like carbon, nitrogen, and oxygen, making them lightweight and durable. Like individual Lego pieces, individual chemical building blocks can be assembled in defined ways to form a larger structure that can be planned in great detail instead of putting components into a mixture and seeing what comes out.

The specific building blocks used in this study are known as porphyrins, a family of organic structures found in proteins like hemoglobin and chlorophyll. These structures include a metal atom at their center, and researchers would like to use this reactive atom to create COF materials with enhanced properties. But despite the wide number of potential applications, ranging from hydrogen storage to carbon capture, these types of COFs have practical limitations. Making COFs is a slow process, and it can take several days just to create a gram of material. Existing methods are also only able to make COF in powder form, making them much harder to process or to transfer onto other materials.

With the team at UNL using their expertise in electropolymerization, a method for controlling polymer synthesis on a substrate that conducts electricity, the researchers found they could use electricity to create thin films of COFs. The resulting material, 2D sheets stacked in multiple layers, is lightweight and heat tolerant and take hours to synthesize instead of days. "This method is fast, simple and cheap, and you enable deposition of a thin film onto a variety of conductive substrates," says Elham Tavakoli, who led the study along with fellow UNL graduate student Shayan Kaviani under the supervision of assistant professor Siamak Nejati. "Through this approach, we can avoid the common challenges with the COF synthesis through conventional solvothermal method."

After studying the structure of the deposited COFs in more detail, however, the researchers found something they couldn't explain: The interlayer distances, or how far the 2D sheets were from one another, were much larger than expected. The experimentalists then turned to theoretical chemists at Penn to determine what was going on.

After trying to create a theoretical model that would accurately describe the COF's structure, Penn postdoc Arvin Kakekhani realized that something must be missing from their model. Kakekhani studied the list of all the chemicals used in the COF's synthesis process to see if any of the additives might explain their unexpected results. The researchers were surprised to find that a "spectator" molecule, one that they thought only provided the electrochemical environment necessary for the reaction to occur, was an essential component of the COF's structure.

The idea that a molecule like pyridine, a small organic molecule with a simple ring structure, can help crystals form is not a new concept in chemistry, but it wasn't thought to be important for COF structure before this study. Now, the researchers have a better understanding of how this spectator fits perfectly within the 2D layers and provides the support needed for the COFs to form a crystal structure. "These smaller pyridine molecules actually go into the material and become part of the crystal," says Kakekhani.

This new approach is now a starting point for creating numerous types of materials. By changing the reaction conditions and the types of COF building blocks use and by replacing the pyridine with another small molecule, the opportunities for creating new materials with unique properties are endless. "COFs are not that old, so they have lots of undiscovered points," says Tavakoli. "I'm looking forward to finding more of these myths in this field."

In the near term, the researchers hope to tune the catalytic properties of synthesized COFs and to develop site-isolated catalysts, substances that increase the rate of a chemical reaction that are essential components of industrial processes. "Our current COF has chemical reactivity, but that can be greatly heightened through small modifications," says Andrew M. Rappe, Blanchard Professor of Chemistry in Penn's School of Arts and Sciences. "Our team can take one platform and make many materials with different functionalities, all based on the work reported here."

"We foresee that the developed platform will allow us to design and realize many functional interfaces not yet explored. A wide range of applications, such as high selectivity separation and efficient catalysis, can be envisioned for these systems," says Nejati.

Kakekhani emphasizes that the work also showcases the importance of having theorists and experimentalists work in close collaboration. "It was not only about to have something that matches their data," he says, "but about generating some insight that can make these materials better. It takes two to tango, and if we find a way to use each other's insight, there is room for discovering new things."

OAK BROOK, Ill. - The presence of a blood clot on the wall of the aorta in people with abdominal aortic aneurysms is associated with more rapid, potentially dangerous growth in the aneurysm, according to a major study published in the journal Radiology. Researchers said the findings could help identify which patients need more aggressive treatment and more frequent follow-up imaging after their initial diagnosis.

The aorta is the major artery that carries oxygenated blood from the heart. Abdominal aneurysms occur when a bulge forms in the portion of the artery that runs through the abdomen. About 200,000 people in the U.S. are diagnosed with the condition every year. Over time, the wall can weaken and rupture. Ruptured abdominal aortic aneurysm is the 10th leading cause of death for men over age 55.

Decisions to surgically repair the aneurysm are based on its diameter. Patients with aneurysms larger than 5.5 centimeters (cm) are normally referred for repair, while those smaller than 5.5 cm are most commonly monitored with imaging at regular intervals. Ultrasound and cross-sectional imaging with CT or MRI are commonly used.

However, this diameter-based management strategy has limitations, as a considerable number of small aneurysms rupture, according to the study's first author, Chengcheng Zhu, Ph.D., assistant researcher from the Department of Radiology and Biomedical Imaging at the University of California in San Francisco.

Dr. Zhu and colleagues focused their study on the intraluminal thrombus, a blood clot on the wall of the aorta at the location of the aneurysm. Intraluminal thrombi are present in the majority of aneurysms close to the repair threshold of 5.5 cm, and in a considerable number of smaller aneurysms. Despite their prevalence, the influence of these clots on abdominal aortic aneurysm growth and rupture risk is still not fully understood.

"Intraluminal thrombus could be a new marker for aneurysm growth," Dr. Zhu said.

The researchers used high resolution cross-sectional imaging with CT or MRI to assess 225 men with abdominal aortic aneurysm. Follow-up lasted, on average, more than 3 years.

Slightly more than half of patients had an intraluminal thrombus. The aneurysms of those with intraluminal thrombus were larger at baseline and grew by a rate of 2 millimeters (mm) per year, twice as fast as the 1 mm per year growth rate in people without intraluminal thrombus.

"An aneurysm with thrombus grows much faster than one without a thrombus," Dr. Zhu said. "Our study looked at a large number of patients with a relatively long follow-up to confirm that thrombus is a new risk factor that may be potentially reported by radiologists."

While the study did not examine the reasons why the presence of a thrombus had such a dramatic impact on aneurysms, Dr. Zhu noted that it likely has harmful biochemical effects on the vessel wall.

"When the vessel wall is covered with thrombus, the lack of oxygen weakens the wall of the vessel, making the aneurysm likely to grow faster and rupture," he said.

The findings suggest that imaging follow-up schedules may need to be adjusted for patients whose aneurysm has a thrombus. Current protocols for follow-up imaging are based on aneurysm size and do not account for the absence or presence of a thrombus.

"A patient at high risk may need closer monitoring," Dr. Zhu said. "If in patients with a thrombus the aneurysm grows twice as fast, then shortening the surveillance interval could be considered."

Dr. Zhu said more research is needed before thrombus detection is integrated into clinical protocols. For now, he said the findings provide another piece of information to use in determining the prognosis of patients with this potentially dangerous condition.

WASHINGTON, January 28, 2020 -- Small magnetic objects, which have been used successfully in technological applications such as data storage, are showing promise in the biomedical field. Magnetic nanostructures have interesting properties that enhance novel applications in medical diagnosis and allow the exploration of new therapeutic techniques.

In this week's Applied Physics Review, by AIP Publishing, researchers review the state of the art in this field. One especially interesting advance involves an exotic nanodisc configuration, known as a vortex state, where magnetic moments arrange into a curly geometry.

Isolating and separating cells from a blood or tissue sample is crucial for a variety of medical applications, such as gene therapy or cancer diagnosis and treatment. Standard procedures involve filtration and centrifugation, but cells of similar sizes or densities cannot be separated this way.

One approach to this problem has been to coat spherical iron oxide beads with antibodies that specifically bind the cells of interest. The desired cells are then separated with applied magnetic fields. However, this can require high magnetic field strengths, so a second approach using nanowires has been tried.

A third way involves nanodiscs, either in a vortex state or a synthetic antiferromagnetic configuration, consisting of two ferromagnetic layers separated by one nonmagnetic layer. The surface of the small structures can be treated with fluorescent probes, allowing the investigators to observe motion of the particles in response to an applied field.

Another biomedical application that can benefit from magnetic nanostructures is MRI. Because the basic technique has low sensitivity, contrast agents are usually needed. The most widely used agents are gadolinium complexes, but these have raised toxicity concerns. Both nanodiscs and nanowires coated with biocompatible substances have properties that would make them good MRI contrast agents.

An innovative application area of magnetic nanostructures involves targeted cell annihilation for cancer treatment. Nanodiscs created in a spin vortex state or synthetic antiferromagnetic configuration show great promise for this use.

High tumor cell death rates, up to 90%, were observed when relatively weak magnetic fields were used with them. The mechanism leading to cell death is a strong mechanical force that results when a rotating magnetic field spins the nanodiscs, destroying tumor cells from the inside.

Most of these studies have been carried out in the lab, so some situations, such as retention or excretion by internal organs or transport through capillaries, could still be an issue. Further study is required to address these real-world effects.

WASHINGTON, January 28, 2020 -- Amyloids are aggregates consisting of stacks of thousands of proteins bound tightly together. Their formation is involved in several widespread disorders, including Alzheimer's disease and Type II diabetes.

In this week's Journal of Chemical Physics, by AIP Publishing, scientists report on a mathematical model for the formation of amyloid fibrils. The model sheds light on how the aggregation process can occur in a catalytic manner, something that has not been previously well understood.

The investigators applied their model to the aggregation of a specific protein associated with Alzheimer's, Ab40. The results show the initiation of the aggregation process for Ab40?fibrils typically occurs at interfaces, such as near the surface of a liquid solution or the glass wall of a test tube. This has important implications for the interpretation of laboratory data used in the study of Alzheimer's and other diseases.

The model consists of a set of mathematical equations, known as rate equations, that describe how protein aggregate concentrations change over time. Each reaction step in the model is shown to be analogous to those in reactions involving enzymes. The role of the enzyme is played by either the tip or side of a growing fiber or, possibly, a surface of the reaction vessel.

The investigators found the mathematical form of their model was related to the famous Michaelis-Menten equations, first published in 1913 to describe the rates of enzyme reactions. It has a far simpler mathematical form than all previous models used for amyloid formation and has the additional advantage that the equations can be solved by hand, without the need for computer simulations.

"We expect the methodology developed in this paper will underpin future efforts to model new amyloid formation phenomena," co-author Alexander Dear said.

One of the key features of the mathematical solution found for Michaelis-Menten-type equations is a phenomenon known as saturation. When saturation occurs, the catalytic sites become fully occupied at high protein concentrations. In the case of the Ab40 studies, saturation also shows that the process initiating aggregation involves a surface, such as the wall of a test tube.

While the conclusions do not directly apply to the body itself, co-author Tuomas Knowles said, "This work will be central in facilitating the study of amyloid formation in the presence of other species found in body fluids."

Co-author Sara Linse said, "This work takes the analysis of experimental data to a new level that will be essential for deriving potent inhibitors of amyloid formation."

WASHINGTON, January 28, 2020 -- Since the Industrial Revolution, the environmental impacts of energy have posed a concern. Recently, this has driven researchers to search for viable options for clean and renewable energy sources.

Due to its affordability and environmental friendliness, hydrogen is a feasible alternative to fossil fuels for energy applications. However, due to its low density, hydrogen is difficult to transport efficiently, and many on-board hydrogen generation methods are slow and energy intensive.

Researchers from the Chinese Academy of Sciences, Beijing and Tsinghua University, Beijing investigate real-time, on-demand hydrogen generation for use in fuel cells, which are a quiet and clean form of energy. They describe their results in the Journal of Renewable and Sustainable Energy, from AIP Publishing.

The researchers used an alloy -- a combination of metals -- of gallium, indium, tin and bismuth to generate hydrogen. When the alloy meets an aluminum plate immersed in water, hydrogen is produced. This hydrogen is connected to a proton exchange membrane fuel cell, a type of fuel cell where chemical energy is converted into electrical energy.

"Compared with traditional power generation methods, PEMFC inherits a higher conversion efficiency," said author Jing Liu, a professor at the Chinese Academy of Sciences and Tsinghua University. "It could start rapidly and run quietly. Moreover, a key benefit to this process is that the only product it generates is water, making it environmentally friendly."

They found the addition of bismuth to the alloy has a large effect on hydrogen generation. Compared to an alloy of gallium, indium and tin, the alloy including bismuth leads to a more stable and durable hydrogen generation reaction. However, it is important to be able to recycle the alloy in order to further reduce cost and environmental impact.

"There are various problems in existing methods for post-reaction mixture separation," Liu said. "An acid or alkaline solution can dissolve aluminum hydroxide but also causes corrosion and pollution problems."

Other byproduct removal methods are difficult and inefficient, and the problem of heat dissipation in the hydrogen reaction process also needs to be optimized. Once these difficulties are resolved, this technology can be used for applications from transportation to portable devices.

"The merit of this method is that it could realize real-time and on-demand hydrogen production," said Liu. "It may offer a possibility for a green and sustainable energy era."

New York, NY--January 28, 2020--A new study from Columbia Engineering and Harvard identified the critical physiological importance of suitable temperatures for butterfly wings to function properly, and discovered that the insects exquisitely regulate their wing temperatures through both structural and behavioral adaptations.

Contrary to common belief that butterfly wings consist primarily of lifeless membranes, the new study demonstrated that they contain a network of living cells whose function requires a constrained range of temperatures for optimal performance. Given their small thermal capacity, wings can overheat rapidly in the sun when butterflies cease flight, and they can cool down too much during flight in a cold environment. The study, published online today by Nature Communications, is the first to explore the implications of temperature in shaping the wing structure and behavior of butterflies.

VIDEO: https://youtu.be/_J-uXQ6D8vQ

"Butterfly wings are essentially vector light-detecting panels by which butterflies can accurately determine the intensity and direction of sunlight, and do this swiftly without using their eyes," says Nanfang Yu, associate professor of applied physics at Columbia Engineering and co-PI of the study.

The team, which was co-led by Naomi E. Pierce, Hessel Professor of Biology in the department of organismic and evolutionary biology, and Curator of Lepidoptera at the Museum of Comparative Zoology, Harvard, used their expertise in biology and optics to make a number of significant discoveries. By carefully removing the wing scales to enable them to peer into the interior of the wings, and by staining the neurons found within the wing, they found that butterfly wings are loaded with a network of mechanical and temperature sensors. The living tissues in the wings are actively supplied by circulatory and tracheal systems throughout the adult lifetime--in the case of painted lady butterflies, for more than three weeks.

They also discovered a "wing heart" that beats a few dozen times per minute to facilitate the directional flow of insect blood or hemolymph through a "scent pad" or an androconial organ located on the wings of some species of butterflies. "Most of the research on butterfly wings has focused on colors used in signaling between individuals," says Pierce., "This work shows that we should reconceptualize the butterfly wing as a dynamic, living structure rather than as a relatively inert membrane. Patterns observed on the wing may also be shaped in important ways by the need to modulate temperatures of living parts of the wing."

Yu's lab designed a noninvasive technique based on infrared hyperspectral imaging, with each pixel of an image representing one infrared spectrum, that enabled them to make--for the first time--accurate measurements of the temperature distributions over butterfly wings. "This has been difficult to do until now," Pierce notes, "because of the thinness and delicacy of butterfly wings." "This imaging technique enables us to examine physical adaptations that decouple the wing's visible appearance from its thermodynamic properties," Yu adds. "We discovered that diverse scale nanostructures and non-uniform cuticle thicknesses create a heterogeneous distribution of radiative cooling--heat dissipation through thermal radiation--that selectively reduces the temperature of living structures such as wing veins and scent pads."

The effect of this regional and selective enhancement of thermal radiation was amply demonstrated in the team's thermodynamic experiments on butterfly wings. Experimental conditions that mimic the butterflies' natural environment were created in Yu's lab, and allowed the researchers to quantify the relative contributions of several environmental factors to the wing temperature. These included the intensity of sunlight, the temperature of the terrestrial environment, and the "coldness" of the sky, which can serve as an efficient heat sink of thermal radiation from heated wings. The team found that in all simulated environmental conditions, despite diverse visible colors and patterns, the areas of butterfly wings that contain live cells (wing veins and scent pads) are always cooler than the "lifeless" regions of the wing due to enhanced radiative cooling. "The nanostructures found in the wing scales could inspire the design of radiative-cooling materials to cope with excessive heat conditions," says Cheng-Chia Tsai, a PhD student in Yu's group who was lead author of the study.

The researchers conducted a series of behavioral studies of living butterflies from six of the seven recognized butterfly families, to investigate responses to simulated sunlight applied to the wings. The team discovered that the insects use their wings to sense the direction and intensity of sunlight--the main source of warmth or overheating--and to respond with specialized behaviors to prevent overheating or overcooling of their wings. For example, all species studied exhibited a relatively constant "trigger" temperature of approximately 40oC (104oF), turning within a few seconds to avoid overheating of wings from a small light spot shone upon them.

Yu and Pierce are now conducting a large-scale systematic optical study of the lepidopteran collections in Harvard's Museum of Comparative Zoology. These include thousands of individual specimens of hundreds of butterfly species across the entire phylogenetic tree, each specimen with full hyperspectral imaging data taken from the ultraviolet to the mid-infrared. In 1863, Henry Walter Bates, an English naturalist and explorer, wrote about butterfly wings in his book The Naturalist on the River Amazons, "On these expanded membranes Nature writes, as on a tablet, the story of the modifications of species ..." Just like deciphering enigmatic symbols on a tablet, the team hopes to gain a comprehensive understanding of the wing coloration and pattern, which are the results of many (and often conflicting) biological and physical factors: sexual selection, warning coloration, mimicry, camouflage, and thermoregulation.

"Each wing of a butterfly is equipped with a few dozen mechanical sensors that provide real-time feedback to enable complex flying patterns," Yu says. "This is an inspiration for designing the wings of flying machines: perhaps wing design should not be solely based on considerations of flight dynamics, and wings designed as an integrated sensory-mechanical system could enable flying machines to perform better in complex aerodynamic conditions."

Eating walnuts may help slow cognitive decline in at-risk groups of the elderly population, according to a study conducted by researchers in California and Spain.

The Walnuts and Healthy Aging Study, published this month in The American Journal of Clinical Nutrition, found that walnut consumption by healthy, elderly adults had little effect on cognitive function over two years, but it had greater effect on elderly adults who had smoked more and had a lower baseline neuropsychological test scores.

The study examined nearly 640 free-living elders in Loma Linda, California, USA, and in Barcelona, Catalonia, Spain. For two years, the test group included walnuts in their daily diet, and the control group abstained from walnuts.

Walnuts contain omega-3 fatty acids and polyphenols, which have previously been found to counteract oxidative stress and inflammation, both of which are drivers of cognitive decline.

Joan Sabaté, MD, DrPH, professor of nutrition and epidemiology at Loma Linda University School of Public Health and the study's principal investigator, said this was the largest and most well-controlled trial ever conducted on the effects of nuts on cognition.

"While this was a minor result, it could lead to better outcomes when conducted over longer periods of time," Sabaté said. "Further investigation is definitely warranted based on our findings, especially for disadvantaged populations, who may have the most to gain from incorporating walnuts and other nuts into their diet."

Sabaté and his research team at Loma Linda University were the first to discover the cholesterol-lowering effect of nut consumption -- specifically walnuts -- with lowering blood cholesterol. Findings were first published in the New England Journal of Medicine in 1993.

Subsequently, findings from Loma Linda University researchers have linked nut consumption to lower risk of cardiovascular diseases.

Surveys show that consumers are worried that smart speakers are eavesdropping on their conversations and day-to-day lives. Now University of British Columbia researchers have found that people are also concerned about something else: friends, family and others who may have access to these devices.

The team spoke to 26 Canadian adults who used shared smart speakers at home, including Amazon Echo, Google Home and Apple HomePod. They found that participants not only worried about keeping their data safe from the manufacturer or other entities; they also feared potential misuse of the device from people they actually live with and know.

"They worried that their housemates could order stuff online, overhear private conversations or access other people's reminders, calendars and phone contacts," explained senior author of the study Konstantin Beznosov, a professor of electrical and computer engineering who specializes in cybersecurity at UBC. "Of course, they were aware these actions could well be unintentional--such as a child accidentally using the last-number-dialled feature to call up their parent's employer, for example."

Interestingly, the nature of the concern depended on the participant's "mental model" or technical understanding of how smart speakers work, notes study primary author Yue Huang, a PhD student in electrical and computer engineering.

"Participants who were very familiar with shared smart speakers were more worried about how technology shortcomings could affect the security of their devices," said Huang. "An example is a smart speaker that occasionally fails to distinguish the main user's voice from another, which means it could grant people access to information they shouldn't have."

However, users with more basic knowledge of how smart speakers work were more focused on their housemates' potential actions, and this sometimes meant seeing a threat where there was none.

"One participant who worried his family member could redial a number was unaware the feature was not even available on the device," said Huang, noting that the study is the first to explore these mental models about shared smart speakers and link these models to attitudes.

These results suggest more work is needed to improve consumers' understanding of shared smart speakers and to make the technology more reliable, adds Beznosov.

"One in four U.S. adults and one in five Canadians say they own a smart speaker. People like being able to stream music, obtain weather forecasts, control other smart devices, and get the news with simple voice commands. But since smart speakers are commonly shared among housemates, technology developers should take into account these consumer concerns. And manufacturers should provide more technical support to help users manage their risks."