Tech

How many tree species are there in the forest? How are the trees scattered throughout? How high are the individual tree crowns? Are there fallen trees or hollowed-out tree trunks? Forest scientists characterize forests according to structural factors. "Structural richness is very important for biodiversity in forests. But forests used for forestry are generally poor in terms of structure," says Tristan Eckerter from the Chair of Nature Conservation and Landscape Ecology at the University of Freiburg. Therefore, together with research teams from the Chair of Silviculture and the Black Forest National Park, he investigated whether structures such as standing timber in forests help to promote the diversity of wild bees. In addition, the researchers analyzed which other natural features of the spruce-dominated forest help wild bees survive. They found that creating deadwood in coniferous forests is a promising restoration measure to promote the abundance of aboveground nesting bees. The scientists recently published their findings in the journal Forest Ecology and Management.

Restauration experiment aims to strengthen biodiversity

As part of this long-term restoration experiment, structural richness was artificially created in 2016 on several sample plots in the Black Forest National Park. Researchers felled and uprooted 20 spruce trees per plot, creating deadwood and small gaps in six 50 by 50 meter plots. Six other plots were left in their natural state as a control group. "The restoration measures have increased what we call the structural complexity of the forest stands. That is, these plots provide a more diverse, varied habitat. We would not have thought to have found so many different wild bees as a result," explains Eckerter.

Standing deadwood promotes bee population

The researchers compared how many wild bees were in the different plots in June 2018 and 2019. Their results show that deadwood increases the abundance and biodiversity of wild bees. In this regard, standing deadwood particularly encourages above-ground nesting bees such as masked bees. "We suspect that some of the bees use deadwood as a nesting site," says Eckerter. As a result, he recommends, "If the bark beetle has already flown out and the tree is already dead, it's important to leave the standing dead tree for the bees."

Increased blueberry growth

In addition, the thinner forest areas prove beneficial to bees, as the light stimulates the growth of flowering plants. Increased blueberry growth provides bees with more nectar, increasing the abundance and richness of the bee community. Looking toward the future, Prof. Dr. Alexandra Klein, head of the Chair of Nature Conservation and Landscape Ecology, emphasizes, „In the course of climate change, forest areas will be increasingly characterized by deadwood and sparse areas caused by storms, droughts or bark beetles. As a result, forest habitat will increase in importance for wild bees."

Most survivors of squamous cell head and neck cancers report that their sense of taste is dulled, changed or lost during radiation treatment, causing them to lose interest in eating and diminishing their quality of life.

In a study of taste and smell dysfunction with 40 cancer survivors, scientists at the University of Illinois Urbana-Champaign found that the tips of these individuals' tongues were significantly less sensitive to bitter, salty or sweet tastes than peers in the control group who had never been diagnosed with cancer.

In a paper published in the journal Chemical Senses, the U. of I. team said this diminished taste sensitivity suggested that the taste buds on the front two-thirds of the cancer survivors' tongues or a branch of the chorda tympani facial nerve, which carries signals from the tip of the tongue to the brain, may have been damaged during radiation therapy.

"While most studies suggest that patients' ability to taste recovers within a few months of treatment, patients report that they continue to experience taste dysfunction for years after treatment ends," said M. Yanina Pepino, a professor of food science and human nutrition at the U. of I. "Our primary goal in this study was to test the hypothesis that radiation therapy is associated with long-term alterations in patients' senses of smell and taste."

While undergoing radiation and/or chemotherapy, head and neck cancer patients may lose taste buds, triggering a transient reduction in their ability to taste - a condition called hypogeusia - or their perception of tastes may be altered, a condition called dysgeusia that can also occur when nerves are damaged during cancer surgery, she said.

"Taste buds' average lifespan of about 10 days enables rapid recovery from injury if the stem cells are preserved, yet it also makes the short-lived and long-lived cells within taste buds particularly vulnerable to the direct cytotoxic and anti-proliferative effects of chemotherapy and radiotherapy," Pepino said.

Prior studies that explored taste loss and perception in these patients showed mixed results. Many of these studies involved "whole mouth" experiments that may not have detected regional damage to the taste buds at the front of the tongue or to the chorda tympani section of the facial nerve, said graduate student Raul Alfaro, the lead author of the study.

The U. of I. team assessed participants' smell and taste functions separately and explored whether sensory interactions between taste and retronasal odors - aromas from food and beverages that are perceived in the oral cavity while eating or drinking - differed for the cancer survivors and the people in the control group.

The team assessed participants' ability to taste regionally by applying cotton swabs soaked in flavored solutions to the tips of their tongues.

They also evaluated participants' whole-mouth taste function by having them swish solutions around in their mouths for five seconds and spit them out. For this test, the participants were presented with nine cups of liquids that contained both taste and smell sensory components. The cups contained two concentrations of strawberry extract in a sucrose solution, lemon extract in citric acid, salt in a vegetable broth and caffeinated instant coffee. They also received one cup of deionized water.

After sipping each sample, participants were asked to identify its taste quality - sweet, salty, bitter, umami (savory) or no sensation - and to rate the smell and taste intensity of the sample on a scale that ranged from "no sensation" to "strongest of any kind."

Participants tasted the samples twice - once wearing a nose clip and once without - to determine whether their taste perception differed when the nose clip blocked their retronasal olfactory cues.

When participants' sense of taste was assessed using the whole-mouth test with or without the nose clip, they similarly rated the taste and smell of nearly all of the samples.

However, when participants' sense of taste was assessed regionally at the tip of the tongue, the cancer survivors were more likely to respond they did not perceive a taste or to misidentify the taste quality - such as bitter, salty or sweet - of multiple samples.

"Although the results from the whole-mouth taste test suggested that head and neck cancer survivors' taste function was normal and well preserved, results from the regional tests indicated that they had some deficits," Pepino said. "Subtle taste dysfunction in the tip of the tongue persisted for several months after they completed their oncology treatments.

"Taste dysfunction at the tip of the tongue might sound unimportant; however, there is an elegant cross-talk between the nerves that conveys signals from the tip and the back of the tongue, such that taste signals in the tip of the tongue inhibit signaling from the back. This system allows taste intensity to remain constant in the whole mouth, even when taste signaling coming from the tip of the tongue is reduced. However, reduced signal input can also lead to phantom tastes, metallic taste and other oral symptoms."

In New England, constraints in the supply of natural gas have led to nearly a quarter of all unscheduled power plant outages. In a new study, researchers used data from power plant failures in the 2010s to develop a supply curve of the costs required for generators to mitigate fuel shortages in the region. The study found that storing both oil and gas on-site could reduce dependence by power plants on gas grids in geographic areas with few pipelines.

The study was conducted by researchers at Carnegie Mellon University (CMU), The Pennsylvania State University, and the North American Electric Reliability Corporation. It is published in The Electricity Journal.

"Gas supply issues have affected the ability to generate electricity during times of high demand," says Jay Apt, Professor at CMU's Tepper School of Business and Department of Engineering and Public Policy, who co-authored the study. "For example, it's estimated that the extended cold weather event in January 2014 cost New England electricity ratepayers roughly $1.8 billion."

New England has no native gas production, so fuel assurance for natural gas power plants is an area of concern; half of all installed power plant capacity in the region is fueled primarily by gas and nearly half of all electricity comes from natural gas power plants. When heating demand spikes on key gas supply pipelines to the region, those pipelines cannot always meet all the region's heating demand and demand for power-plant fuel at the same time.

The effect of gas supply constraints on Northeastern power generators can be seen by comparing the average fraction of total unscheduled generator outages due to gas fuel unavailability to those during days of high demand for heating. In recent periods of high electricity and gas demand, unscheduled gas shortages accounted for 5 to 25 percent of all unscheduled generator outages during every hour of those periods.

Dual fuel capability--that is, the ability to burn either oil or gas--is one way to mitigate gas supply shortages, and about a third of ISO New England's natural gas power plant capacity has dual fuel capability (ISO New England is an independent, not-for-profit corporation that manages the high-voltage power system over six New England states). But building dual fuel storage tanks for the remainder has been considered prohibitively expensive.

In 2019, one of the study's coauthors--Seth Blumsack, Professor of Energy Policy and Economics at The Pennsylvania State University--developed a model to identify where to build distributed gas storage capability in New England. To increase reliability of the interdependent gas and electricity grids, Blumsack and his students identified economically optimal sites for distributed gas storage in the region. They concluded that power plant sites might be the optimal locations for gas storage.

In this study, researchers analyzed a database of historical power plant failures, using data from the North American Electric Reliability Corporation--NERC--a not-for-profit international reliability organization. They determined what the cost of on-site fuel storage at natural gas power plants would have to be to mitigate the worst gas shortages in New England during the seven years studied.

The study assessed 54 gas-fired units operating within ISO New England that had NERC reports of full or partial outages due to unscheduled fuel shortages between 2012 and 2018. For each unit, researchers calculated the overnight capital, fuel carrying, and land costs (when applicable) required for gas generators in the region to assure that fuel supplies using fuel storage systems were sized according to their most extreme fuel shortage failure during the study period. They also examined distributed compressed natural gas storage at generator sites and dual fuel capabilities with oil storage. The researchers compared these costs to those of installing batteries with enough capacity to cover historically observed fuel outages.

The researchers found that approximately 2.4 gigawatts (GW) of ISO New England's gas-fired capacity failed one or more times per year due to fuel shortages; up to 0.5 GW of these units failed simultaneously on three separate occasions. Of these, approximately 2 GW of gas-fired capacity could be mitigated by on-site fuel storage. Furthermore, gas plants would recoup their investment in oil backup fuel if they were compensated with an additional $3 to $7 per megawatt-hour (MWh) during their normal operations.

Using on-site compressed natural gas storage is more expensive ($7 to $16/MWh). The capital expenses associated with either on-site fuel storage option would be less than installing battery backup for resource adequacy at current battery prices, the study concluded.

"Our estimates differ from previous studies because they are based on actual failure events rather than arbitrary fuel supply durations," explains Gerad Freeman, an Energy Systems Research Engineer at Pacific Northwest National Laboratory, the study's lead author. "As such, they have implications for moving forward on increasing dual fuel capacity to increase the resilience of power systems in New England and other regions with similar gas supply constraints."

The authors note that limitations to this research include that they may oversize the dual fuel storage by basing fuel storage tank sizes on the longest observed gas outage at each unit, that batteries can receive some revenue by providing grid services during non-emergencies, and that compressed natural gas storage might help balance gas supply and demand.

BROOKLYN, New York, Wednesday, June 23, 2021 -- Owing to their tunable properties, hydrogels comprising stimuli-sensitive polymers are among the most appealing molecular scaffolds because their versatility allows for applications in tissue engineering, drug delivery and other biomedical fields.

Peptides and proteins are increasingly popular as building blocks because they can be stimulated to self-assemble into nanostructures such as nanoparticles or nanofibers, which enables gelation -- the formation of supramolecular hydrogels that can trap water and small molecules. Engineers, to generate such smart biomaterials, are developing systems that can respond to a multitude of stimuli including heat. Although thermosensitive hydrogels are among widely studied and well-understood class of protein biomaterials, substantial progress is also reportedly being made in incorporating stimuli-responsiveness including pH, light, ionic strength, redox, as well as the addition of small molecules.

A team of researchers at the NYU Tandon School of Engineering, who previously reported a responsive hydrogel formed using a coiled-coil protein, Q, expanded their studies to identify the gelation of Q protein at distinct temperatures and pH conditions. The study, "Self-assembly of stimuli-responsive coiled-coil fibrous hydrogels," appears in the Royal Society of Chemistry journal Soft Matter.

Jin Kim Montclare, professor of chemical and biomolecular engineering, with affilations at NYU Langone Health and NYU College of Dentistry, directed this research with first author Michael Meleties, fellow Ph.D. student Dustin Britton, postdoctoral associate Priya Katyal, and undergraduate research assistant Bonnie Lin.

Using transmission electron microscopy, rheology and structural analyses, they observed that Q self-assembles and forms fiber-based hydrogels exhibiting upper critical solution temperature (UCST) behavior with increased elastic properties at pH 7.4 and pH 10. At pH 6, however, Q forms polydisperse nanoparticles, which do not further self-assemble and undergo gelation. The high net positive charge of Q at pH 6 creates significant electrostatic repulsion, preventing its gelation. This study will potentially guide the development of novel scaffolds and functional biomaterials that are sensitive towards biologically relevant stimuli

Montclare explained that upper critical solution temperature (UCST) phase behavior is characterized by a solution that will form a hydrogel when it is cooled below a critical temperature.

"In our case, it is due to the physical crosslinking/entanglement of fibers that our fiber-based hydrogel forms when cooled," she said, adding that when the temperature is raised above the critical temperature, the hydrogel transitions back into solution and most of the fibers should disentangle.

"In our study, we looked at how this process is affected by pH. We believe that the high net charge of the protein at pH 6 creates electrostatic repulsions that prevent the protein from assembling into fibers and further into hydrogels, while at higher pH where there would be less electrostatic repulsion, the protein is able to assemble into fibers that can then undergo gelation."

Hospitalizations to treat pediatric gun injuries are expensive, and U.S. taxpayers and the poor are bearing the price, according to a new study from the Stanford University School of Medicine.

The study, which published online June 23 in PLOS ONE, found that the average cost of an initial hospitalization for a pediatric firearm injury is around $13,000. A total of about $109 million is spent on such hospitalizations in the country each year. The figures do not capture the total costs of rehabilitating young gunshot victims, which can be much higher.

Research into the financial, health and social costs of firearm injuries in the United States has focused mostly on adults, said the study's senior author, Stephanie Chao, MD, assistant professor of surgery.

However, nine of every 10 firearm injuries to children worldwide occur in the United States, according to a study published in 2015 in The American Journal of Medicine.

"We really need a better picture of the overall toll of firearms on children," Chao said.

Although gun deaths from school shootings and other mass-casualty incidents are widely publicized, most pediatric gun injuries occur less publicly, often when children accidentally discharge firearms they locate and handle without their parents' knowledge. "This takes a horrible toll on families and children's lives, and there is a financial toll," Chao said.

Drawing attention to kids' firearm accidents

For their study, the researchers used data on pediatric gun injuries from the Kids' Inpatient Database, which is compiled once every three years using discharge data from more than 4,100 U.S. hospitals. The researchers examined medical records from children released after their initial hospitalization for firearm injuries in 2003, 2006, 2009 and 2012.

They found that 19,015 children age 18 and under were hospitalized for firearm injuries during the four years included in the study, with an average of 4,753 admissions each year. About three-quarters of the injuries occurred in patients 16 to 18 years old. Injuries were caused by assault in 63% of cases and by unintentional discharge of a firearm in 26% of cases. In 3% of cases, injuries were self-inflicted. Most of the remainder were of undetermined cause.

Chao noted that the vast majority of children and teens who attempt suicide using firearms do not survive to be admitted to a hospital, so the study could not capture the impact of most self-inflicted wounds on families and communities.

The cost of hospitalizations to treat firearm injuries in children rose with time, even after adjusting for inflation, the study found. More than half of that cost, over $62 million per year, was paid by Medicaid, and a substantial additional portion of the cost was borne by uninsured patients, who accounted for 11% of all hospitalizations.

The results highlight how gun safety could be improved to protect children, Chao said, noting that the proportion of unintentional firearm injuries was especially high in young children. Among children age 5 and younger, 60% of gun injuries were unintentional, while among those aged 6-10, the figure was 56%.

"Accidental discharge of guns is something that is really actionable for lawmakers and pediatricians," Chao said, noting that doctors can educate families about the need to store guns locked and unloaded, and legislators can pass laws to restrict children's access to firearms. States with laws that restrict children's gun access have fewer pediatric gun injuries and fatalities, Chao's prior research has shown.

Not only would keeping children safe reduce families' heartache, it would also free up funding to support children's health in other ways, Chao said. "A lot of children are being harmed, and that's costly to our health care system," she said. "If we could prevent these injuries, the money could be spent in so many other places."

The study's lead author is Jordan Taylor, MD, a resident in surgery.

Other co-authors are research assistant Sriraman Madhavan; Ryan Han, undergraduate student in computer science; Julia Chandler, MD, resident in surgery; and Lakshika Tennakoon, research data scientist.

New York, NY--June 23, 2021--A challenging frontier in science and engineering is controlling matter outside of thermodynamic equilibrium to build material systems with capabilities that rival those of living organisms. Research on active colloids aims to create micro- and nanoscale "particles" that swim through viscous fluids like primitive microorganisms. When these self-propelled particles come together, they can organize and move like schools of fish to perform robotic functions, such as navigating complex environments and delivering "cargo" to targeted locations.

A Columbia Engineering team led by Kyle Bishop, professor of chemical engineering, is at the forefront of studying and designing the dynamics of active colloids powered by chemical reactions or by external magnetic, electric, or acoustic fields. The group is developing colloidal robots, in which active components interact and assemble to perform dynamic functions inspired by living cells.

In a new study published today by Physical Review Letters, Bishop's group, working with collaborators at Northwestern University's Center for Bio-Inspired Energy Science (CBES), report that they have demonstrated the use of DC electric fields to drive back-and-forth rotation of micro-particles in electric boundary layers. These particle oscillators could be useful as clocks that coordinate the organization of active matter and even, perhaps, orchestrate the functions of micron-scale robots.

"Tiny particle oscillators could enable new types of active matter that combine the swarming behaviors of self-propelled colloids and the synchronizing behaviors of coupled oscillators," says Bishop. "We expect interactions among the particles to depend on their respective positions and phases, thus enabling richer collective behaviors--behaviors that can be designed and exploited for applications in swarm robotics."

Making a reliable clock at the micron-scale is not as simple as it may sound. As one can imagine, pendulum clocks don't work well when immersed in honey. Their periodic motion--like that of all inertial oscillators--drags to a halt under sufficient resistance from friction. Without the help of inertia, it is similarly challenging to drive the oscillatory motion of micron-scale particles in viscous fluids.

"Our recent observation of colloidal spheres oscillating back and forth in a DC electric field presented a bit of mystery, one we wanted to solve," observes the paper's lead author, Zhengyan Zhang, a PhD student in Bishop's lab who discovered this effect. "By varying the particle size, field strength, and fluid conductivity, we identified experimental conditions needed for oscillations and uncovered the mechanism underlying the particles' rhythmic dynamics."

Earlier work has demonstrated how similar particles can rotate steadily by a process known as Quincke rotation. Like a water wheel filled from above, the Quincke instability is driven by the accumulation of electric charge on the particle surface and its mechanical rotation in the electric field. However, existing models of Quincke rotation--and of overdamped water wheels--do not predict oscillatory dynamics.

This new study characterizes and explains the "mysterious" oscillations by reference to a boundary layer in the nonpolar electrolyte. Within this layer, often ignored by researchers, charge carriers are generated and then migrate away under the influence of the electric field. These processes introduce spatial asymmetries in the rates of charge accumulation at the particle surface. Like a water wheel whose buckets leak faster at the top than at the bottom, asymmetric charging can lead to back-and-forth rotation at high field strengths.

"The limited generation rate of charges in these weak electrolytes creates a boundary layer comparable to the size of particle under a strong electric field, as found numerically by my PhD student Hang Yuan, a co-author of the work. As a result, the 'conductivity' of ions around particles that are within the large boundary layer is not constant, leading to the observed oscillations at strong electric fields," says Monica Olvera de la Cruz, Lawyer Taylor Professor of Materials Science and Engineering, Chemistry and (by courtesy) Chemical and Biological Engineering, Physics and Astronomy at Northwestern Engineering.

"This work shows a way to generate oscillators, which could lead to the emergence of cooperative phenomena in fluids," she adds.

The team experimented with different shapes of particles and found they could generate oscillations with any particles, provided that their size was comparable to that of the boundary layer.

"By tuning the field strength and/or the electrolyte, we can predictably control the frequency of these `Quincke clocks,'" Bishop adds. "Our paper enables the design of new forms of active matter based on collections of mobile oscillators."

The team is currently studying the collective behaviors that emerge when many Quincke oscillators move and interact with one another.

A new study published in Nature Communications finds that piles of sand grains, even when undisturbed, are in constant motion. Using highly-sensitive optical interference data, researchers from the University of Pennsylvania and Vanderbilt University present results that challenge existing theories in both geology and physics about how soils and other types of disordered materials behave.

Most people only become aware of soil movement on hillsides when soil suddenly loses its rigidity, a phenomenon known as yield. "Say that you have soil on a hillside. Then, if there's an earthquake or it rains, this material that's apparently solid becomes a liquid," says principal investigator Douglas Jerolmack of Penn. "The prevailing framework treats this failure as if it's a crack breaking. The reason that's problematic is because you're modeling the material by a solid mechanical criterion, but you're modeling it at the point at which it becomes a liquid, so there's an inherent contradiction."

Such a model implies that, below yield the soil is a solid and therefore should not flow, but soil slowly and persistently "flows" below its yield point in a process known as creep. The prevailing geological explanation for soil creep is that it is caused by physical or biological disturbances, such as freeze-thaw cycles, fallen trees, or burrowing animals, that act to move soil.

In this study, lead author and Penn Ph.D. candidate Nakul S. Deshpande was interested in observing individual sand particles at rest which, based on existing theories, should be entirely immobile. "Researchers have built models by presuming certain behaviors of the soil grains in creep, but no one had actually just directly observed what the grains do," says Deshpande.

To do this, Deshpande set up a series of seemingly simple experiments, creating sand piles in small plexiglass boxes on top of a vibration isolation worktable. He then used a laser light scattering technique called diffusing-wave spectroscopy, which is sensitive to very small grain movements. "The experiments are technically challenging," Deshpande says about this work. "Pushing the technique to this resolution is not yet common in physics, and the approach doesn't have a precedent in geosciences or geomorphology."

Deshpande and Jerolmack also worked with long-time collaborator Paulo Arratia, who runs the Penn Complex Fluids Lab, to connect their data with frameworks from physics, materials science, and engineering to find analogous systems and theories that could help explain their results. Vanderbilt's David Furbish, who uses statistical physics to study how particle motions influence large-scale landscape changes, provided explanation for why previous models were physically inadequate and inconsistent with what the researchers had found.

The first experiments were seemingly easy: Pour a pile of sand into the box, let it sit, and watch with the laser. But the researchers discovered that, while intuition and prevailing theories say that the undisturbed piles of sand should be static, sand grain piles are in fact a mass of constant movement and behave like glass.

"In every way that we can measure the sand, it is relaxing like a cooling glass," says Deshpande. "If you were to take a bottle and melt it, then freeze it again, that behavior of those molecules in that cooling glass are, in every way that we're capable of measuring, just like the sand."

In physics, glass and soil particles are classic examples of a "disordered" system, one whose constituent particles are arranged randomly instead of in crystalline, well-defined structures. While disordered materials, a major focus area of Penn's Materials Research Science & Engineering Center, share some common behaviors in terms of how they deform when stressed, there is an important difference between glass and a pile of sand. The molecules that make up glass are always moving randomly at a rate that depends on temperature, but sand grains are too large to do that. Because of that, physicists expect that a pile of sand would be "jammed" and unmoving, but these latest findings present a new way of thinking about soil for researchers in both physics and geology.

Another surprising result was that the rate of creeping soil could be controlled based on the types of disturbances used. While the undisturbed sandpile continued to creep for as long as the researchers observed, the rate of particle motion slowed through time in a process called aging. When sand particles were heated, this aging was reversed such that creep rates increased back to their initial value. Tapping the pile, in contrast, accelerated aging.

"We tend to think of things that drive soil toward yield, like shaking from an earthquake that triggers a landslide, but other disturbances in nature potentially drive soil further away from yield, or make it harder for a landslide to happen," says Jerolmack. "Nakul's ability to tune it further or closer to yield was like a bomb that went off for us, and this is an all-new area."

In the near term, the researchers are working on follow-up experiments to recreate the impacts of localized disturbances using magnetic probes to understand how disturbances could lead a system further away from or closer to yield. They are also looking at data from field observations, from natural soil creep to catastrophic landslide events, to see if they can connect their lab experiments to what observers see in the field, potentially enabling new ways to detect catastrophic landscape failures before they happen.

The researchers hope that their work can be a starting point for refining existing theories that rely on a paradigm that, like a hillside whose soil particles have shifted over time, no longer holds weight. "When you observe something really counterintuitive and new, it's going to now take a long time before that turns into a model to use," says Jerolmack. "I hope on the geoscience side that people with sophisticated tools and techniques and experience will pick up where we've ended and say, 'I have a new idea for seeking this signature in the field that you wouldn't have thought of'--that natural handoff of scales and abilities and interests."

SILVER SPRING, Md.-- Although Americans spend billions on them, published research shows a lack of strong evidence that dietary supplements and alternative therapies help adults lose weight, according to a new study published in Obesity, the flagship journal of The Obesity Society (TOS).

There are hundreds of weight-loss supplements like green tea extract, chitosan, guar gum and conjugated linoleic acid, and an estimated 34% of Americans who are trying to lose weight have used one.

For the study, researchers completed a comprehensive review of 315 existing clinical trials of weight loss supplements and therapies, and most of the studies showed the supplements did not produce weight loss among users.

"Our findings are important for clinicians, researchers, and industry alike as they suggest the need for rigorous evaluation of products for weight loss," said corresponding author John Batsis, MD, associate professor in the Division of Geriatric Medicine at the University of North Carolina (UNC) School of Medicine, and in the Department of Nutrition at the UNC Gillings School of Global Public Health. "Only then can we produce data that allows clinicians to provide input and advice with a higher degree of certainty to our patients."

The evaluation should also be collaborative as the supplement industry and academics work together to design high-quality clinical trials of weight loss supplements, Batsis added.

The paper's authors explain that patients often struggle to lose or maintain weight either because of a lack of efficacy of existing Federal Drug Administration (FDA)-approved therapies or a lack of access to healthcare professionals who provide treatments for obesity.

Even though the National Institutes of Health's Office of Dietary Supplements has advanced the science of dietary supplements by evaluating information, and stimulating and supporting research, members of TOS decided it was important to evaluate and perform a qualitative synthesis of non-FDA therapies to provide scientific evidence to guide its membership.

Researchers conducted a systematic literature review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to evaluate the efficacy of dietary supplements and alternative therapies for weight loss in participants aged 18 and older. Searches of Medline (Pubmed), Cochrane Library, Web of Science, CINAHL and Embase (Ovid) were performed.

Researchers focused on 315 peer-reviewed randomized-controlled trials and analyzed them for risk of bias. Results classified 52 studies as low risk of bias and sufficient to support efficacy. Of these, 16 studies demonstrated significant pre/post intergroup differences in weight compared with placebos. In these methodologically distinct studies, the weight loss ranged widely from 0.3 to 4.93 kg.

In a perspective written by members of TOS's Clinical Committee led by Srividya Kidambi, MD, MS, Division of Endocrinology and Molecular Medicine, Medical College of Wisconsin in Milwaukee who also co-authored the paper, members recommend to clinicians to consider the lack of evidence of non-FDA-approved dietary supplements and therapies and guide their patients toward tested weight-management approaches. "Public and private entities should provide adequate resources for obesity management. We call on regulatory authorities to critically examine the dietary supplement industry, including their role in promoting misleading claims and marketing products that have the potential to harm patients," the authors write in the paper.

A potent greenhouse gas, methane is released by many sources, both human and natural. Large cities emit significant amounts of methane, but in many cases the exact emission sources are unknown. Now, researchers reporting in ACS' Environmental Science & Technology have conducted mobile measurements of methane and its sources throughout Paris. Their findings suggest that the natural gas distribution network, the sewage system and furnaces of buildings are ideal targets for methane reduction efforts.

In cities, major sources of atmospheric methane include heating systems, landfills, wastewater and road transport. Plans for reducing greenhouse gas emissions have been enacted for the city of Paris, but to be successful in reducing methane emissions, sources in the city need to be precisely mapped and quantified. To draw a baseline to assess future mitigation policies and actions, Sara Defratyka and colleagues conducted repeated mobile measurements around the city to identify methane leaks.

The researchers conducted 17 street-level surveys throughout Paris from September 2018 to March 2019. The team used either vehicle-mounted instruments or portable instruments for walking measurements to detect methane and its probable source, based on the gas's isotopic signature. A total of 90 potential methane leaks were detected in Paris, with 27 of them identified. Of these, 63% of emissions came from natural gas distribution networks, 33% from sewage networks and 4% from heating furnaces of buildings. Based on these findings, the researchers estimated that the total methane emission rate of Paris is about 190 metric tons per year. The actual number is likely higher because not all streets were surveyed, and the method does not report mobile methane sources from road transport, the researchers say.

A fair society has evolved in banded mongooses because parents don't know which pups are their own, new research shows.

Mothers in banded mongoose groups all give birth on the same night, creating a "veil of ignorance" over parentage in their communal crèche of pups.

In the new study, led by the universities of Exeter and Roehampton, half of the pregnant mothers in wild mongoose groups were regularly given extra food, leading to increased inequality in the birth weight of pups.

But after giving birth, well-fed mothers gave extra care to the smaller pups born to the unfed mothers - rather than their own pups - and the pup size differences quickly disappeared.

Dr Harry Marshall, of the Department of Life Sciences at the University of Roehampton, said: "In most of the natural world, parents favour their own young.

"However, in banded mongooses, the evolution of remarkable birth synchrony has led to the unusual situation that mothers don't know which pups are their own, and therefore cannot choose to give them extra care.

"Our study shows that this ignorance leads to a fairer allocation of resources - in effect, a fairer society."

The study examined seven groups of banded mongooses in Uganda. Half of the pregnant females in each group were given 50g of cooked egg each day, while the other half were not given extra food.

Inequality at birth (measured by weight) was wider in breeding periods when food was provided than in periods where no extra food was given.

Professor Michael Cant, of the University of Exeter said: "We predicted that a 'veil of ignorance' would cause females to focus their care on the pups most in need - and this is what we found.

"Those most able to help offer it to the most needy, and in doing so minimise the risk that their own offspring will face a disadvantage.

"This redistributive form of care 'levelled up' initial size disparities, and equalised the chances of pups surviving to adulthood.

"Our results suggest that the veil of ignorance, a classic philosophical idea to achieve fairness in human societies, also applies in this non-human society."

The research team included Professor Rufus Johnstone, from the University of Cambridge.

Funding for the study came from the European Research Council and the Natural Environment Research Council.

The paper, published in the journal Nature Communications, is entitled: "A veil of ignorance can promote fairness in a mammal society."

Women who currently use hormonal contraceptives face more than a 2-fold higher risk of developing glaucoma, according to an analysis of electronic medical records for women aged 15-45 years from 2008 to 2018. The British Journal of Clinical Pharmacology analysis included 2,366 women who developed glaucoma and 9,464 controls.

Although current users of hormonal contraceptives may have a higher risk of developing glaucoma, their risk is still low. Also, an elevated risk was not seen in women who used hormonal contraceptives in the past.

Women with more than four prescriptions for hormonal contraceptives in the last two years had a higher risk of developing glaucoma than those taking one or two prescriptions.

"The risk of glaucoma with hormonal contraceptives is low and should not dissuade women from taking these medications. Women on hormonal contraceptives who experience visual changes should have these symptoms examined by an ophthalmologist," said senior author Mahyar Etminan, PharmD, MSc, of The University of British Columbia, in Canada.

A study published in Economic Inquiry that examined data from 133 countries from 1950-2014 found that a reduction in fiscal space--with fiscal space being the ability of governments to provide resources without undermining fiscal sustainability--in high income countries following the global financial crisis in 2007-2009 prevented these economies from adopting countercyclical fiscal policies. A countercyclical fiscal policy stance aims to smooth out business cycle fluctuations, through greater spending during recessions and lower spending during booms.

The study finds that a reduction of fiscal space led to an opposite--or procyclical--policy action, cutting spending further during the downturn, with serious negative consequences for the overall state of the economy.

In the context of the COVID-19 crisis, the findings point to the importance of building fiscal space in "better" financial times to allow for the capacity to adopt countercyclical policies during downturns.

"Our study points to a reversal of fortune in the conduct of fiscal policy. Whereas low and middle income countries were seen to conduct procyclical policy in the past, tables have turned in the aftermath of the global financial crisis with high income countries being associated with policies that have aggravated business cycle fluctuations, prolonging periods of economic downturn," said corresponding author Gulcin Ozkan, PhD, of King's College London. "Importantly, we highlight that it is a lack of fiscal space which drives these results, and that better policies in good times will allow for more responsive policies during crisis periods."

Research led by scientists at the University of Bristol has shed new light on how the kidneys of the one-humped Arabian camel play an important role in helping it to cope with extremes.

In a new paper published today in the journal Communications Biology, they have studied the response of the camel's kidneys to dehydration and rapid rehydration stresses.

Camelus dromedarius is the most important livestock animal in the arid and semi-arid regions of North and East Africa, the Arabian Peninsula and Iran, and continues to provide basic needs to millions of people.

Thought to have been domesticated 3,000 to 6,000 years ago in the Arabian Peninsula, the camel has been used as a beast of burden, for riding and sport, and to produce milk, meat and shelter, and they are still used today for the same purposes.

This animal is so incredibly well adapted to the desert environment that can endure weeks without access to water. A very well-developed kidney is the key to produce highly concentrated urine and assure water is never wasted.

In the current context of advancing desertification and climate change, there is renewed interest in the adaptations of camels. Further, advanced laboratory techniques allow to study the underlying genetic mechanisms of these adaptations.

However, there was not to date, a freely available and comprehensive study of the genes implicated in coping with dehydration in the kidney of the camel.

This project was born in 2015 with the onset of a fruitful collaboration between Professor David Murphy's Lab at University of Bristol and Professor Abdu Adem's Lab at United Arab Emirates University.

The team analysed how thousands of genes changed in the camel kidney as a consequence of dehydration and rehydration and suggested that the amount of cholesterol in the kidney has a role in the water conservation process. They used different techniques to further validate these results.

Lead authors Fernando AlviraI Iraizoz and Benjamin T. Gillard from the University of Bristol's Medical School, said: "A decrease in the amount of cholesterol in the membrane of kidney cells would facilitate the movement of solutes and water across different sections of the kidney - a process that is required to efficiently reabsorb water and produce a highly concentrated urine, thus avoiding water loss.

"This is, to the best of our knowledge, the first time that the level of cholesterol has been directly associated with water conservation in the kidney. Thus, we describe a novel role for this lipid that may be of interest when studying other species."

The team also presents an immense source of information that, as mentioned by one of the reviewers, is very valuable in the context of climate change and thus will help scientists to understand the mechanisms of water control in dehydration.

Following the publication of this research, the team are now looking at how the camel brain responds to the same stimuli and how other species, such as jerboas and Olive mice, adapt to life in the deserts.

BOSTON - Research has previously linked inflammation to Alzheimer's disease (AD), yet scientists from Massachusetts General Hospital (MGH) and the Harvard Aging Brain Study (HABS) have made a surprising discovery about that relationship. In a new study published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association, they report that elevated levels of two chemical mediators of inflammation, known as cytokines, are associated with slower cognitive decline in aging adults.

"These are totally unexpected results," says the study's co-senior author, Rudolph Tanzi, PhD, vice chair of Neurology and co-director of the Henry and Allison McCance Center for Brain Health at MGH. These findings could eventually be used to help identify healthy people who are at risk for the devastating neurological condition, before they have symptoms.

In 2008, Tanzi led a team that discovered CD33, the first AD gene associated with the immune system (or the body's defense network that fights infection). Since then, most new AD genes identified have been linked to the immune system, and many studies support the theory that immune system dysfunction plays a part in AD. Notably, research has shown that people with AD and other forms of dementia have elevated levels of certain cytokines.

However, until now the role of the immune system in the earliest stage of AD--when brain changes characteristic of the disease silently progress in older adults without cognitive symptoms--was unclear. In the new study, Tanzi and his team collaborated with HABS investigators to find out if measuring cytokines in the blood (instead of in cerebrospinal fluid, which requires a lumbar puncture procedure, or spinal tap) could help predict which healthy people will later experience cognitive decline. Of particular interest were older people with normal cognition, but who had undergone imaging tests and were found to have deposits of amyloid beta--the major component of amyloid plaques, which are associated with AD--in their brains. "We wanted to know why some people have amyloid in their brain and don't seem to be affected, while other people experience cognitive decline," says study co-senior author Jasmeer Chhatwal, MD, PhD, a neurologist at MGH and a HABS co-investigator.

The partnership between the McCance Center and HABS, which is co-led by Reisa Sperling, MD, and Keith Johnson, MD, "was a natural fit," says Chhatwal, since both groups seek to understand the secrets of healthy aging and identify biomarkers of brain health. Moreover, HABS had rich data to examine. The new study included 298 men and women from HABS, who were between the ages 50 and 90. All had normal cognitive abilities when they volunteered and undergo retesting annually. Upon joining HABS, all participants had blood samples taken and underwent positron emission tomography (PET) brain-imaging scans; among other things, these scans looked for evidence of amyloid beta and other changes associated with AD, such as formations called tau tangles.

The study screened each participant's blood for nine cytokines to see if any were associated with the rate of cognitive decline and changes in the brain. The study found that people whose brains had a significant burden of amyloid beta, but who also had high levels of a pro-inflammatory cytokine called interleukin-12 (IL-12), experienced little cognitive decline. "However, men and women with elevated levels of amyloid declined more if they had a lower value of IL-12," says lead author Hyun-Sik Yang, MD, a neurologist at Brigham and Women's Hospital and a HABS co-investigator. High levels of IL-12 were also associated with fewer tau tangles. Meanwhile, elevated levels of another pro-inflammatory cytokine, interferon-gamma (IFN-γ), were associated with slower cognitive decline, whether or not a person had deposits of amyloid.

While it may seem counterintuitive that people who were protected against cognitive decline had the highest levels of inflammation-inducing proteins in the blood, that may be an indication that their immune systems were better "primed" to fight infection, says Tanzi. That would fit with a theory he developed with the late Robert Moir, PhD, a researcher at MGH and Harvard University, in which they hypothesized that amyloid beta forms in the brain as a defense against infection, ensnaring microbial pathogens in a sticky web. Unfortunately, the once-protective shield turns destructive over time, causing irreversible damage to neurons and synapses. However, having high levels of IL-12 and IFN-γ "may nip infections in the bud, before they can leak into the brain and induce Alzheimer's pathology," says Tanzi.

These results suggest that IL-12 and IFN-γ could one day be measured along with other biomarkers to predict future brain health in cognitively normal people--a tool that doesn't yet exist in medicine. "We don't have a 'checkup from the neck up'," says Tanzi. The next step toward that goal will be studying how IL-12 and IFN-γ may ward off cognitive decline and promote healthy brain aging.

Tanzi is the Vice-Chair of Neurology (Research) and Co-Director of the Henry and Allison McCance Center for Brain Health at MGH, and the Joseph P. and Rose F. Kennedy Professor of Neurology at Harvard Medical School (HMS). Chhatwal is an assistant professor of Neurology at HMS. Yang is an assistant professor of Neurology at HMS.

As the saying goes, an apple a day keeps the doctor away. But what's the key to growing a quality apple?

Apple trees need access to important nutrients, which come from the soil. However, soil is quite different from orchard to orchard.

Gregory Peck studies how sustainable orchard practices can improve the availability of nutrients. The research was recently shared in Soil Science Society of America Journal, a publication of the Soil Science Society of America.

Farmers are becoming more aware of the environmental impacts of different orchard management practices.

"Apple growers are interested in developing more sustainable nutrient management plans," explains Peck. "They are asking for more information to improve the soil health on their farms."

A healthy soil depends on many factors. One of those factors is the microbial community living in the soil. The community is made up of bacteria, nematodes, and fungi. Some of these microbes convert nutrients in the soil into forms that apple trees can use.

In the soil, microbes and plant roots interact in beneficial partnerships. Plants, like apple trees, release fluids from their roots into the soil. These fluids serve as a food source for the microbial community. In return, the microbes can help the apple trees.

"Bacteria serve many functions in an apple orchard soil," says Peck. "They recycle nutrients, promote plant growth, and even alter plant metabolisms."

In this study, the team applied composts - such as chicken litter and yard waste - to apple orchards.

Researchers found that adding compost increased the number of soil bacteria associated with recycling nutrients. The compost provides additional food for the bacteria to help them thrive.

This larger microbial community means more nutrients are available to the apple trees.

By applying compost, farmers could reduce the amount of fertilizer needed to provide nutrients for apple trees. This could help their pocketbooks and the environment.

Some fertilizers come from non-renewable sources. Adding in compost to a farm's nutrient management plan reduces the dependence on those sources. It also provides a sustainable use for materials otherwise considered to be waste.

On a practical level, this research shows that farmers can successfully integrate compost with quicker release fertilizer sources.

"Although sustainable apple production is not defined by a single practice, we think this research contributes to the long-term goal of increasing farm sustainability," says Peck.

In the future, the team hopes to replicate this study in different regions with different soil characteristics. They would also like to take a deeper look into the roles of fungi in the microbial community of orchard soils.

"We can produce great apples, and apple orchard farmers can supply a huge population with delicious, nutritious food," Peck adds.