Culture

A new method of brain imaging analysis offers the potential to greatly improve the effectiveness of noninvasive brain stimulation treatment for Alzheimer's, obsessive compulsive disorder, depression, and other conditions. Duke researchers developed the new method, which for the first time analyzed the whole brain network rather than a single region of the brain. This new method identified brain areas that exert the most control on network function.

The study, published in the Journal of Neuroscience, has direct implications for improving the benefits of transcranial magnetic stimulation, which is currently used for major depression and obsessive compulsive disorder, and may soon lead to therapeutic treatment for memory disorders such as Alzheimer's and dementia.

Researchers at the Duke Brain Stimulation Research Center (BSRC) developed a method of analysis that relies on the concept of controllability, a network principle that helps to predict how one area of the brain influences a whole network involved in regulating behavior.

The authors measured controllability using functional magnetic resonance imaging (fMRI) to determine how much change TMS would induce as participants did a working memory task. In this task, individuals had to keep bits of information briefly in their memory and manipulate this information in their mind before answering questions about it. This task was used because of the importance of working memory in everyday life (like ordering your shopping list in your mind before walking through the grocery store) and because it is highly impacted by aging, particularly in conditions like Alzheimer's and dementia.

"Essentially, we look at the brain not as a set of discrete islands, but as a dense web of connections that have lots of mutual influence," said lead researcher Dr. Simon Davis, PhD, Assistant Professor of Neurology at Duke. "Controllability allows us a framework for identifying which nodes in this web are most likely to be influenced by brain stimulation, and for that reason likely to show plasticity and improvement after TMS treatments."

The controllability measure, which is based on a static, structural image of the brain, was used to predict dynamic activity. "Brain activity is like the spatial pattern of traffic in a city. Although the traffic pattern is ever-changing, it is always confined by the topology of the road network," said Lifu Deng, a Duke graduate student in the Department of Psychology and Neuroscience, and co-lead on the paper. "Controllability links the stimulation at one location to the global pattern of brain activity. In our study, for instance, this is the activation patterns signifying better working memory."

Previously, there has not been a systematic way to identify which brain areas are the most likely to produce global chances, because most studies have focused on just one region. This study, however, advanced the field by considering the whole brain network.

While healthy adults participated in the study, the research likely has implications for memory disorders. "Memory dysfunction as a network phenomenon that relies on multiple brain regions operating under coordinated dynamics. The typical focus on the TMS response at a single site represents a fundamental limitation in the approach of neurostimulation therapies because it neglects global impairments in whole network that underlies memory dysfunction," said Lysianne Beynel, PhD, a postdoctoral associate in the BSRC and first author on the study.

Ultimately, this non-invasive brain stimulation method will be used to promote healthy brain activity patterns and eventually enhance memory function, which has potential to enhance the efficacy of brain stimulation treatments for a range of cognitive disorders.

A revolutionary group of scientists has been rethinking for two decades how we understand bird song, with women leading the way. Several of these scientists are from UMBC, and their latest research has revealed findings not just about birds, but about bird researchers.

Elaborate bird song had been considered mostly a male trait for centuries, famously discussed by Charles Darwin. But Karan Odom, Ph.D. ’16, biological sciences, published a landmark paper on female bird song in 2014 that helped change that viewpoint. Odom’s study found that as many as 70 percent of female birds sing. Her extensive research also established firmly that both sexes almost certainly sang in the common ancestor of all bird species—a radical idea in ornithology.

Odom conducted research at UMBC with Kevin Omland, professor of biological sciences, whose lab has led much of the research in this area. Now, a new paper led by Casey Haines ’19, biological sciences, has documented what the Omland group and others have suspected all along: Women are more likely than men to be authors, and even more likely to be first authors (research leads), on papers about female bird song. Therefore, it is largely women who have reshaped this classical field of study. 

The findings, published this week in Animal Behaviour, suggest that a diverse group of researchers is critical for scientific innovation. Diversity could also help build a more accurate and complete understanding of bird biology and other fields.

A fresh perspective

Haines and Omland completed the research with co-authors Odom and Evangeline Rose, a Ph.D. candidate in Omland’s lab. They examined 59 bird song papers published between 1997 and 2016. 

The researchers found that women made up 56 percent of all authors on female bird song papers, compared with only 40 percent of authors of general bird song papers. Women held 68 percent of first-author positions on female bird song papers, but only 44 percent of first-author positions on general bird song papers. This means men were 24 percentage points less likely than women to lead a study on female bird song, and 16 percent less likely to contribute to a female song study in any way, compared with their contributions to general bird song papers.

“I believe this paper is a great example of how diversity expands the type of research scientists are doing,” Haines says. “Female bird song research has been underrepresented in the literature until only recently. A diverse pool of researchers may result in new questions being asked and new approaches to answering those questions. I would love to see this type of research applied in other areas of STEM.”

Other research cited in the new paper has found that women are more likely to study female animals (including humans), which have been historically understudied, as well as species that have gotten less attention in research. Female authors also publish more often with women co-authors, opening doors to greater funding and opportunities for more women in science. 

More generally, research has shown that diversity among scientists leads to greater creativity in questions, ideas, and methods.

A starting point

Omland acknowledges that this kind of study is outside his lab’s avian evolution wheelhouse, but he hopes it will spark further conversations. “We’re able to add an important data point to these discussions,” he says. And while the new paper has been in the works for some time, “In this moment, this research seems to have gained an increased weight.”

Haines and colleagues acknowledge that their study is imperfect. For example, “Our data represent gender in a binary framework, which is not reflective of society, potentially resulting in mis-gendering authors who are non-binary or gender minorities,” the paper states. “Gender minority authors make important contributions to science and are a vital part of increasing diversity. We recommend that more-detailed future studies provide opportunities for authors to self-identify their gender to avoid the possibility of mis-gendering.”

Even with its limitations, the paper provides an important glimpse into gender dynamics in ornithology. For an emerging researcher like Haines, it was an eye-opening experience. 

“Personally, it was amazing to find that the percentage of women who hold first-author positions on female bird song has increased so much within the last 20 years,” Haines says. “I think it speaks volumes on how far both female bird song and women in science have come.”

Creating space for new leaders

Haines herself is on a path to pursue graduate study in animal behavior based on her experience in the Omland lab. “Working with Dr. Omland, Evangeline, and the rest of the Omland lab was definitely the most memorable and enjoyable part of my time at UMBC,” she says.

Omland has a history of nurturing undergraduate researchers. In fact, Haines’s paper is the tenth peer-reviewed journal article published with an undergraduate first author from his lab. “Undergraduate researchers have really influenced the trajectory of our lab’s research by making consistent, significant contributions,” Omland says.

“It’s essential that we continue to build environments where researchers from all backgrounds are encouraged to explore new ideas and ask new questions,” Omland says. “Not only will this enable them to reach their potential as scientists, but it is also essential to expanding our knowledge of the world around us.”

Journal

Animal Behaviour

DOI

10.1016/j.anbehav.2020.07.021

Scientists at Johns Hopkins Medicine using MRI scans and computer modeling say they have further pinpointed areas of the human brain that regulate efforts to deal with fatigue.

The findings, they say, could advance the development of behavioral and other strategies that increase physical performance in healthy people, and also illuminate the neural mechanisms that contribute to fatigue in people with depression, multiple sclerosis and stroke.

Results of the research were published online Aug. 12 in Nature Communications.

"We know the physiologic processes involved in fatigue, such as lactic acid build-up in muscles, but we know far less about how feelings of fatigue are processed in the brain and how our brain decides how much and what kind of effort to make to overcome fatigue," says Vikram Chib, Ph.D., assistant professor of biomedical engineering at the Johns Hopkins University School of Medicine and research scientist at the Kennedy Krieger Institute.

Knowing the brain regions that control choices about fatigue-moderating efforts can help scientists find therapies that precisely alter those choices, says Chib. "It might not be ideal for your brain to simply power through fatigue," says Chib. "It might be more beneficial for the brain to be more efficient about the signals it's sending."

For the study, Chib first developed a novel way to objectively quantify how people "feel" fatigue, a difficult task because rating systems can vary from person to person. Physicians often ask their patients to rate their fatigue on a scale of 1 to 7, but like pain scales, such ratings are subjective and varied.

To standardize the metric for fatigue, Chib asked 20 study participants to make risk-based decisions about exerting a specific physical effort. The average age of participants was 24 and ranged from 18 to 34. Nine of the 20 were female.

The 20 participants were asked to grasp and squeeze a sensor after training them to recognize a scale of effort. For example, zero was equal to no effort and 50 units of effort were equal to half the participant's maximum force. The participants learned to associate units of effort with how much to squeeze, which helped to standardize the effort level among individuals.

The participants repeated the grip exercises for 17 blocks for 10 trials each, until they were fatigued, then were offered one of two choices for making each effort. One was a random ("risky") choice based on a coin flip, offering the chance to exert no effort or a predetermined effort level. The other choice was a predetermined set effort level. By introducing uncertainty, the researchers were tapping in to how each subject valued their effort -- a way, in effect, of shedding light on how their brains and minds decided how much effort to make.

Based on whether the participant chose a risky option versus the predetermined one, the researchers used computerized programs to measure how participants felt about the prospect of exerting particular amounts of effort while they were fatigued.

"Unsurprisingly, we found that people tend to be more risk averse -- to avoid -- effort," says Chib. Most of the participants (19 of 20) opted for the risk-free choice of a predetermined effort level. This means that, when fatigued, participants were less willing to take the chance of having to exert large amounts of effort.

"The predetermined amount had to get pretty high in relative effort for participants to choose the coin toss option," says Chib.

Among a separate group of 10 people trained on the gripping system but not given numerous, fatiguing trials, there was no significant tendency toward picking either the risky coin toss or defined effort.

Chib's research team also evaluated participants' brain activity during the gripping exercises using functional magnetic resonance imaging (fMRI) scans, which track blood flow through the brain and show which neurons are firing most often.

Chib's team confirmed previous findings that brain activity when participants chose between the two options seemed to increase in all participants in an area of the brain's known as the insula.

Also using fMRI scans, they took a closer look at the motor cortex of the brain when the participants were fatigued. This region of the brain is responsible for exerting the effort itself.

The researchers found that the motor cortex was deactivated at the time participants "decided" between the two effort choices. That finding is consistent, Chib says, with previous studies showing that when people perform repeated fatiguing exertions, motor cortex activity is decreased, associated with fewer signals being sent down to the muscles.

Participants whose motor cortex activity changed the least, in response to fatiguing exertion, were the ones who were most risk averse in their effort choices and were most fatigued. This suggests that fatigue might arise from a miscalibration between what an individual thinks they are able to achieve and the actual activity in motor cortex.

Essentially, the body attunes to the motor cortex when fatigued, because if the brain kept sending more signals to muscles to act, physiological constraints would begin to take over, for example, increased lactic acid, contributing to even more fatigue.

These findings, says Chib, may advance the search for therapies -- physical or chemical -- that target this pathway in healthy people to advance performance and in people with conditions that are associated with fatigue.

The Gerontological Society of America's highly cited, peer-reviewed journals are continuing to publish scientific articles on COVID-19, and all are free to access. The following were published between July 24 and August 25; all are free to access:

Modern Senicide in the Face of a Pandemic: An Examination of Public Discourse and Sentiment about Older Adults and COVID-19 Using Machine Learning: Research report in The Journals of Gerontology, Series B: Psychological Sciences and Social Sciences by Xiaoling Xiang, PhD, MSW, Xuan Lu, PhD, Alex Halavanau, PhD, Jia Xue, PhD, Yihang Sun, MSW, Patrick Ho Lam Lai, MSW, and Zhenke Wu, PhD

Calculated Ageism: Generational Sacrifice as a Response to the COVID-19 Pandemic: Research report in The Journals of Gerontology, Series B: Psychological Sciences and Social Sciences by Anne E. Barrett, PhD, Cherish Michael, MS, and Irene Padavic, PhD

Prisons and COVID-19: A Desperate Call for Gerontological Expertise in Correctional Healthcare: Brief report in The Gerontologist by Stephanie Grace Prost, PhD, Meghan A. Novisky, PhD, Leah Rorvig, MD, Nick Zaller, PhD, and Brie Williams, MD

Scientists have discovered that testing the levels of certain proteins in blood samples can predict whether a person at risk of psychosis is likely to develop a psychotic disorder years later.

The study is published in the current edition of JAMA Psychiatry and was led by researchers from RCSI University of Medicine and Health Sciences.

Based on certain criteria, such as mild or brief psychotic symptoms, some people are considered to be clinically at high risk of developing a psychotic disorder, such as schizophrenia. However, only 20% to 30% of these people will actually go on to develop a psychotic disorder.

The researchers analysed blood samples taken from people at clinical high risk of psychosis. These individuals were followed up for several years to see who did and did not develop a psychotic disorder.

After assessing the proteins in blood samples and using machine learning to analyse this data, the scientists were able to find patterns of proteins in the early blood samples that could predict who did and did not develop a psychotic disorder at follow-up.

Many of these proteins are involved in inflammation, suggesting that there are early changes in the immune system in people who go on to develop a psychotic disorder. The findings also suggest that it is possible to predict their outcomes using blood samples taken several years in advance.

The most accurate test was based on the 10 most predictive proteins. It correctly identified those who would go on to develop a psychotic disorder in 93% of high-risk cases, and it correctly identified those who would not in 80% of cases.

"Ideally, we would like to prevent psychotic disorders, but that requires being able to accurately identify who is most at risk," said Professor David Cotter, the study's senior and corresponding author and professor of molecular psychiatry at RCSI.

"Our research has shown that, with help from machine learning, analysis of protein levels in blood samples can predict who is at truly at risk and could possibly benefit from preventive treatments. We now need to study these markers in other people at high risk of psychosis to confirm these findings."

A patent application has been filed, and the research team is working to commercialise this research through licensing or partnering with industry.

Healthcare systems around the world need to develop ways of supporting people in the community who are recovering from COVID-19, say researchers.

If they don't, there is a risk that people experiencing long-term symptoms will get worse and put additional strain on already-stretched health resources.

Although COVID-19 starts as an acute infection of the lungs, it can develop into a "multi-system illness" leaving people with symptoms that can last for months and years - including breathlessness, fatigue, weakness, pain, cardiac problems, cognitive and psychological problems.

More than one-third of the people who have been severely ill with the disease could have long-term symptoms, some of them debilitating.

The study - Development of an integrated rehabilitation pathway for individuals recovering from COVID-19 in the community - by experts from the University of Leeds, Leeds Teaching Hospitals NHS Trust, Leeds Community Healthcare NHS Trust and NHS Leeds Clinical Commissioning Group has been published in the Journal of Rehabilitation Medicine.

Dr Manoj Sivan, Associate Clinical Professor at the University of Leeds and a Consultant in Rehabilitation Medicine in the NHS Trusts, led the research project. He said: "It has been estimated that to date, 23 million people worldwide have been infected by the disease. Most will have experienced a mild illness but a sizeable minority, up to one million, will have after-effects that will last for many months and possibly years.

"We know from previous outbreaks of Spanish flu, SARS and Ebola that up to a third of survivors can suffer from long term problems, particularly chronic fatigue that has implications on family life, work and health economy.

"With COVID-19, there is an opportunity to intervene early, provide timely specialist rehabilitation, and ensure people have the best functional recovery and return to their vocation as early as possible."

Lisa Hollingworth, Senior Commissioning Manager at NHS Leeds, said: "Collaboration between commissioners and providers in the city has resulted in the development of clinical guidance and new pathways for the provision of rehabilitation services post COVID-19, including a specialist Multi- Disciplinary Team.

"The resource investment to date is £500,000 supported by NHS Leeds Clinical Commissioning Group."

How patients in Leeds are screened

The researchers describe a telephone screening and referral service that has been pioneered by the Leeds COVID-19 rehabilitation teams at Leeds Teaching Hospitals and Leeds Community Healthcare NHS Trusts.

People who have been severely ill with COVID-19 are contacted either by their GP or a specialist member of the hospital's rehabilitation team six and 12 weeks after recovering from the acute phase of the illness. They are asked a series of questions about - and scored on - any persistent symptoms and how well they are functioning.

The questionnaire called C19-YRS (Yorkshire Rehabilitation Screen) takes about 15 minutes to complete.

The screening identifies symptoms that need to be urgently assessed by relevant specialist healthcare professionals in secondary or primary care services. Services include respiratory medicine, pulmonary rehabilitation, physiotherapy, occupational therapy, psychology or combined multidisciplinary clinics.

Self-help resources have been developed, and the NHS England is planning a website 'Your COVID Recovery' which is expected to go live soon.

Dr Ian Clifton, Honorary Senior Lecturer at the University of Leeds and Consultant in Respiratory Medicine, added: "One of the challenges we face is that COVID-19 is a new disease and we do not yet know the course that people will follow as they recover. It is essential that recovery services have input from a range of specialties, so expert help is on hand when and where it is needed."

Research by Dr Sivan and colleagues earlier in the summer identified the common longer-term symptoms experienced by COVID-19 survivors who were severely ill with the disease. The top three were fatigue, breathlessness and psychological distress.

Current sequencing techniques lack the sensitivity to detect rare gene mutations in a pool of cells, which is particularly important, for example, in early cancer detection. Now, scientists at KAUST have developed an approach, called targeted individual DNA molecule sequencing (IDMseq), that can accurately detect a single mutation in a pool of 10,000 cells.

Importantly, the team successfully used IDMseq to determine the number and frequency of mutations caused by the gene editing tool, CRISPR/Cas9, in human embryonic stem cells. Clinical trials are underway to test CRISPR's safety to treat some genetic diseases. "Our study revealed potential risks associated with CRISPR/Cas9 editing and provides tools to better study genome editing outcomes," says KAUST bioscientist Mo Li, who led the study.

IDMseq is a sequencing technique that involves attaching a unique barcode to every DNA molecule in a sample of cells and then making a large number of copies of each molecule using a polymerase chain reaction (PCR). Copied molecules carry the same barcode as the original ones.

A bioinformatics tool kit, called variant analysis with unique molecular identifier for long-read technology (VAULT), then decodes the barcodes and places similar molecules into their own "bins", with every bin representing one of the original DNA molecules. VAULT uses a combination of algorithms to detect mutations in the bins. The process works especially well with third-generation long-read sequencing technologies and helps scientists detect and determine the frequency of all types of mutations, from changes in single DNA letters to large deletions and insertions in the original DNA molecules.

The approach successfully detected a deliberately caused gene mutation that was mixed with a group of wild-type cells at ratios of 1:100, 1:1,000 and 1:10,000. It also correctly reported its frequency.

The researchers also used IDMseq to look for mutations caused by CRISPR/Cas9 genome editing. "Several recent studies have reported that Cas9 introduces unexpected, large DNA deletions around the edited genes, leading to safety concerns. These deletions are difficult to detect and quantitate using current DNA sequencing strategies. But our approach, in combination with various sequencing platforms, can analyze these large DNA mutations with high accuracy and sensitivity," says Ph.D. student Chongwei Bi.

The tests found that large deletions accounted for 2.8-5.4 percent of Cas9 editing outcomes. They also discovered a three-fold rise in single-base DNA variants in the edited region. "This shows that there is a lot that we need to learn about CRISPR/Cas9 before it can be safely used in the clinic," says Yanyi Huang of Peking University, who is an international collaborator co-funded by KAUST.

IDMseq can currently sequence only one DNA strand, but work to enable double-strand sequencing could further improve performance, say the researchers.

In a study published in the Journal of Morphology, a team of researchers from New Jersey Institute of Technology (NJIT), Florida Museum of Natural History, Louisiana State University and Thailand's Maejo University have successfully pieced together the ancestral relationships that make up the family tree of hillstream loaches (Balitoridae), detailing for the first time a range of unusual pelvic adaptations across the family that have given some of its members an ability to crawl, or even walk as salamanders do, to navigate terrestrial surfaces.

The team's DNA-based comparative analysis of the fish family, known to currently encompass more than 100 species native to South and Southeast Asia, is the first of its kind to include Cryptotora thamicola -- the only living species of fish known to walk on land in a step pattern similar to tetrapods, or four-limbed vertebrates such as reptiles and amphibians.

The results have revealed that three dominant variations of pelvic anatomy in the family, notably including key variations of a robust pelvic girdle and elongated sacral rib among many loaches, which researchers expect are central in explaining the different degrees of land-walking behavior exhibited by the fishes. The team says that the family's modified pelvic features enabling terrestrial locomotion, which were found most pronounced in Cryptotora thamicola, may have been adapted to enhance their odds of survival in rivers and other fast-moving water environments that many Balitoridae inhabit today.

"The modified morphology of these Balitoridae, particularly the enlarged sacral rib connecting the pelvic plate to the vertebral column, is a big part of why studying this family is so exciting," said Callie Crawford, the study's corresponding author and Ph.D. candidate at NJIT's Department of Biological Sciences. "These loaches have converged on a structural requirement to support terrestrial walking not seen in other fishes. What we've discovered is three anatomical groupings that have major implications for the biomechanics of terrestrial locomotion of these loaches, and the relationships among these fishes suggest that the ability to adapt to fast-flowing rivers may be what was passed on genetically, more than the specific morphology itself."

"Now that we have revealed a spectrum of pelvic morphologies among these fishes, we can compare the extent of skeletal support with the walking performance in a species," said Brooke Flammang, the study's lead principal investigator and assistant professor of biology at NJIT. "This will allow us to measure the mechanical contribution of robust hips to terrestrial locomotion."

Unlike most living fishes that feature pelvic fins located more anteriorly and attached to the pectoral girdle, balitorids typically boast a skeletal connection between the pelvic plate (basipterygium) and the vertebral column via a modified sacral rib and its distal ligament. These modifications are understood to help generate force against the ground useful for navigating land. The most extreme example emerged in 2016 with the discovery of Cryptotora thamicola in the fast-flowing aquatic conditions of the Tham Maelana and Tham Susa karst cave systems in northern Thailand. NJIT researchers then first identified that the rare species used a robust pelvic girdle attached to its vertebral column to walk and climb waterfalls with a salamander-like gait.

"This trait is likely key to helping these fishes avoid being washed away in the fast-flowing environment that they live in," said Zach Randall, co-author of the paper and biological scientist at Florida Museum of Natural History. "What's really cool about this paper is that it shows with high detail that robust pelvic girdles are more common than we thought in the hillstream loach family."

"The sacral ribs allow forces from the fins pressing against the ground to be transferred to the body so that every time the fin pushes down during a step, the body is pushed up and forward," explained Flammang. "The increased surface area of the more modified sacral ribs also offers more room for muscle attachment, so fishes such as Cryptotora thamicola can rotate their hips during walking, producing a salamander-like gait."

River Loach Family Factions

To better understand the evolution of the river loach family, the team conducted a broad sampling of μCT-scan data taken from 29 representative specimens, analyzing and comparing skeletal structures, muscle morphology as well as sacral rib shape across 14 of the 16 balitorid genera. The team also sampled genomic datasets of 72 loaches across seven families to reconstruct the evolutionary relationships in the Ballitoridae tree of life. "We were able to use a large survey of museum specimens and CT scanning to incorporate data even from specimens that didn't have tissue or genetic data intact," noted Randall.

The results showed that the loaches fall into three distinct morphotypes, which are expected to correlate to how well they are able to maneuver on land: species with a long, narrow rib that meets the pelvic plate; species with a thicker, slightly curved rib meeting the pelvic plate; and species with a robust crested rib interlocking with the pelvic plate. Of the species sampled, eleven fell into the third category with advanced land-walking abilities, such as Cryptotora thamicola, displaying the most robust sacral rib connection between the basipterygium and vertebral column.

"Our analysis showed that the morphotypes are not grouped by closely related taxa, but instead appear spread out across the phylogeny. That indicates to us that the extent of the modification of these features is less reflecting shared ancestry and more likely a product of adaptation to the flow regimes of their environments," explained Crawford. "To better understand how and why these distinct morphotypes developed, we need more knowledge of the habitat of each species, including water flow rates, substrate types and how the rivers and streams change between rainy and dry seasons."

Crawford and colleagues now aim to further investigate the stability physics and muscular forces at play that allow certain species to push their bodies off their ground as they walk. The team, including a recent Rutgers University graduate, Amani Webber-Schultz, recently completed fieldwork in Thailand earlier this year to collect more balitorid specimens, which they are studying using high-speed videos of the fishes walking.

"This will allow us to study details of their walking kinematics and gain even more insight into how walking performance might change between species with different pelvic morphologies," said Crawford.

Scientists at the U.S. Department of Energy's Ames Laboratory have discovered a metal-free carbon-based catalyst that has the potential to be much less expensive and more efficient for many industrial concerns, including manufacturing of bio- and fossil fuels, electrocatalysis, and fuel cells.

At their most fundamental, these industry processes involve splitting strong chemical bonds, like hydrogen-hydrogen, carbon-oxygen, and carbon-hydrogen bonds. Traditionally this has been accomplished with catalysts that use transition or precious metals, many of them expensive and low in natural abundance -- like platinum and palladium.

The scientists performed experiments with a type of heterogeneous catalyst, Nitrogen-Assembly Carbons (NACs), in which the design and placement of nitrogen on the carbon surface greatly influenced the catalytic activity of the material. These N atoms on carbon surfaces were previously believed to be distant from one another, as the close placement of N atoms is thermodynamically unstable. The team in Ames Lab correlated the N precursors and pyrolysis temperature for the NACs synthesis with the N distribution and discovered that meta-stable N assemblies can be made by design and deliver unexpected catalytic reactions. Such reactions include hydrogenolysis of aryl ethers, dehydrogenation of ethylbenzene and tetrahydroquinoline, and hydrogenation of common unsaturated functionalities (such as ketone, alkene, alkyne, and nitro groups). Moreover, the NACs catalysts are robust with consistent selectivity and activity for both liquid and gas phase reactions under high temperature and/or pressure.

"We discovered that how the nitrogen was distributed on the surface of these NACs really mattered, and in the process realized that this was an entirely new kind of chemical activity," said Ames Laboratory Associate Scientist Long Qi.

"The discovery should enable scientists to design nitrogen assemblies that are able to accomplish more sophisticated and challenging chemical transformations without the need for transition metals" said Ames Laboratory scientist Wenyu Huang. "It broadly applies to many different types of chemical conversions and industries."

Washington, DC (August 2020) - Good news for pasta eaters! New research published in Frontiers in Nutrition this month, analyzing the diets of adults and children who eat pasta, has revealed good news about one of America's favorite foods. The research found that pasta consumption in both children and adults is associated with a better diet quality and better nutrient intakes than that of those adults and children who do not eat pasta. Furthermore, when evaluating weight parameters, no associations were observed in male adults and children. In adult women however, pasta-eaters showed a beneficial weight-related outcome. Pasta consumption in adult females was associated with reduced waist circumference, body weight and body mass index (BMI).

The research, "Pasta Consumption is Linked to Greater Nutrient Intakes and Improved Diet Quality in American Children and Adults, and Beneficial Weight-Related Outcomes Only in Adult Females" was conducted by Nutritional Strategies, Inc. on behalf of the National Pasta Association. The study examined associations between pasta consumption, shortfall nutrient intakes as defined by the 2015 Dietary Guidelines (2015 DG) and diet quality in comparison to non-pasta consumption in the U.S. population (children (ages 2-18) and adults (> 19 years). Pasta consumption was defined as all dry domestic and imported pasta/noodle varieties made with only wheat and no egg. From the analysis, researchers identified a number of key positive nutritional dietary patterns associated with those who eat pasta as part of their diet compared to those who don't eat pasta. They are:

- Better overall diet quality (as measured by USDA's Healthy Eating Index-2010 scale)

- Greater intake of key shortfall nutrients

a. In adults these were: folate, iron, magnesium, and dietary fiber

b. In children these were: folate, iron, magnesium, dietary fiber and vitamin E

- Lower daily intakes

a. Saturated fat and added sugars in adults

b. Saturated fat and total fat in children

- No differences were seen in total daily calories and sodium intake.

- No significant associations were seen with body weight, waist circumference and body mass index in children and adult males. In adult women (19 -50 years), pasta eating was associated with lower body weight and waist circumference.

Pasta is a convenient, nutritious, easy-to-prepare meal for both young and old and pleases even the pickiest of eaters. It has long been celebrated as one of America's favorite foods and is advocated by nutritionists for its good nutrition.

"Pasta can be an effective building block for good nutrition throughout the lifecycle, as it serves as a perfect delivery system for fruits, vegetables, lean meats, fish and legumes," explains registered dietitian Diane Welland, Director of Nutrition Communications for the National Pasta Association. "Think of pasta as a canvas from which you can add almost any nutrient-dense, fiber-rich food you and your family like, to create memorable and delicious meals. This analysis underscores the nutritional importance of grains, such as pasta, as consistent with a healthy diet. It shows that pasta eaters have better quality diets than those who don't eat pasta."

Within cells, molecules known as transfer RNAs, or "tRNAs," play an important but unglamorous workhorse role in keeping the genetic translation process moving along from codes of DNA to functional proteins.

Because they play such a vital role in this translational "housekeeping," tRNAs are plentiful. There are hundreds of tRNA genes in mammalian cells and more than enough backup copies, just in case anything goes wrong. Yet because there are so many tRNAs, they've been largely overlooked in the search for the roots of disease processes.

University of California San Diego scientists studying tRNAs in mice have now found that a mutation in a tRNA gene called n-Tr20--expressed only in the brain--can disrupt the landscape of the entire cell, leading to a chain reaction altering brain function and behavior.

The new research is described August 26 in the journal Neuron.

Study first author Mridu Kapur, a postdoctoral scholar working in Professor Susan Ackerman's laboratory, says she and her colleagues found that n-Tr20 plays a role in the delicate balance of excitatory and inhibitory neurotransmission in the brain. A disruption in this balance has been implicated in numerous neurological diseases, including epilepsies and autism spectrum disorders.

"tRNAs have generally been overlooked in the hunt for the genetic causes of disease, but recent whole-genome sequencing projects have revealed that there are many variations in tRNA sequences in the human population," said Kapur. "Our study suggests the enormous potential for tRNA variants to contribute to disease outcomes and phenotypic variability."

The researchers found that a loss of n-Tr20, one of the members of a five-gene tRNA family, made mice resistant to seizures. While they note that their initial interest in this area came from the idea that a tRNA mutation could subsequently influence other gene mutations, their results not only confirm their speculations that tRNA mutations can influence other mutations, but indicate that these mutations alone can also alter brain function.

"You can imagine it's like a seesaw--if you push either way you can have problems," said Ackerman, a member of the Section of Neurobiology, Department of Cellular and Molecular Medicine and investigator at the Howard Hughes Medical Institute. "Keeping balance of these two opposing forces is essential for normal function. Shifting one way or another can lead to neurological diseases. It's becoming well accepted in the autism spectrum disorder field that what we are really seeing is an imbalance of excitatory/inhibitory neurotransmission."

Ackerman says part of the reason tRNAs have been overlooked in disease investigations is because researchers commonly concentrate on mutations in unique genes. A member of a large family such as n-Tr20 typically gets tossed in the genetic garbage can because they are too similar to one other.

"We never knew a mutation in a multi-copy tRNA gene could do anything like this," said Ackerman. "These findings make you think about people who have diseases with variable symptoms and how much this class of overlooked genes could be playing a role in their disease. So we're seeing this go from a behavior, such as seizure, all the way to the molecular underpinnings causing them."

The researchers say the results are likely the tip of the iceberg and are now turning their attention to studying tRNA links to disease in tissues outside the brain.

Irvine, Calif., Aug. 26, 2020 - The detection more than a decade ago by the Fermi Gamma Ray Space Telescope of an excess of high-energy radiation in the center of the Milky Way convinced some physicists that they were seeing evidence of the annihilation of dark matter particles, but a team led by researchers at the University of California, Irvine has ruled out that interpretation.

In a paper published recently in the journal Physical Review D, the UCI scientists and colleagues at Virginia Polytechnic Institute and State University and other institutions report that - through an analysis of the Fermi data and an exhaustive series of modeling exercises - they were able to determine that the observed gamma rays could not have been produced by what are called weakly interacting massive particles, most popularly theorized as the stuff of dark matter.

By eliminating these particles, the destruction of which could generate energies of up to 300 giga-electron volts, the paper's authors say, they have put the strongest constraints yet on dark matter properties.

"For 40 years or so, the leading candidate for dark matter among particle physicists was a thermal, weakly interacting and weak-scale particle, and this result for the first time rules out that candidate up to very high-mass particles," said co-author Kevork Abazajian, UCI professor of physics & astronomy.

"In many models, this particle ranges from 10 to 1,000 times the mass of a proton, with more massive particles being less attractive theoretically as a dark matter particle," added co-author Manoj Kaplinghat, also a UCI professor of physics & astronomy. "In this paper, we're eliminating dark matter candidates over the favored range, which is a huge improvement in the constraints we put on the possibilities that these are representative of dark matter."

Abazajian said that dark matter signals could be crowded out by other astrophysical phenomena in the Galactic Center - such as star formation, cosmic ray deflection off molecular gas and, most notably, neutron stars and millisecond pulsars - as sources of excess gamma rays detected by the Fermi space telescope.

"We looked at all of the different modeling that goes on in the Galactic Center, including molecular gas, stellar emissions and high-energy electrons that scatter low-energy photons," said co-author Oscar Macias, a postdoctoral scholar in physics and astronomy at the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo whose visit to UCI in 2017 initiated this project. "We took over three years to pull all of these new, better models together and examine the emissions, finding that there is little room left for dark matter."

Macias, who is also a postdoctoral researcher with the GRAPPA Centre at the University of Amsterdam, added that this result would not have been possible without data and software provided by the Fermi Large Area Telescope collaboration.

The group tested all classes of models used in the Galactic Center region for excess emission analyses, and its conclusions remained unchanged. "One would have to craft a diffuse emission model that leaves a big 'hole' in them to relax our constraints, and science doesn't work that way," Macias said.

Kaplinghat noted that physicists have predicted that radiation from dark matter annihilation would be represented in a neat spherical or elliptical shape emanating from the Galactic Center, but the gamma ray excess detected by the Fermi space telescope after its June 2008 deployment shows up as a triaxial, bar-like structure.

"If you peer at the Galactic Center, you see that the stars are distributed in a boxy way," he said. "There's a disk of stars, and right in the center, there's a bulge that's about 10 degrees on the sky, and it's actually a very specific shape - sort of an asymmetric box - and this shape leaves very little room for additional dark matter."

Does this research rule out the existence of dark matter in the galaxy? "No," Kaplinghat said. "Our study constrains the kind of particle that dark matter could be. The multiple lines of evidence for dark matter in the galaxy are robust and unaffected by our work."

Far from considering the team's findings to be discouraging, Abazajian said they should encourage physicists to focus on concepts other than the most popular ones.

"There are a lot of alternative dark matter candidates out there," he said. "The search is going to be more like a fishing expedition where you don't already know where the fish are."

LONDON, ONTARIO - A team from Lawson Health Research Institute and Western University has made significant steps forward in understanding COVID-19 through two back-to-back studies published this week in Critical Care Explorations. In one study, the team has identified six molecules that can be used as biomarkers to predict how severely ill a patient will become. In the other study, they are the first to reveal a new mechanism causing blood clots in COVID-19 patients and potential ways to treat them.

The studies were conducted by analyzing blood samples from critically ill patients at London Health Sciences Centre (LHSC). They build on a growing body of work from the team who were first in the world to profile the body's immune response to the virus by revealing a separate six molecules that could act as potential targets to treat hyperinflammation in critically ill patients.

"We've begun answering some of the biggest COVID-19 questions asked by clinicians and health researchers," says Dr. Douglas Fraser, lead researcher from Lawson and Western's Schulich School of Medicine & Dentistry, and Critical Care Physician at LHSC. "While the findings need to be validated with larger groups of patients, they could have important implications for treating and studying this disease."

Predicting which COVID-19 patients will get worse

With no proven therapies, many COVID-19 patients admitted to intensive care units (ICUs) do not survive.

"When a patient is admitted to ICU, we normally wait to see if they are going to get worse before we consider any risky interventions. To improve outcomes, we not only need new therapies but also a way to predict prognosis or which patients are going to get worse," explains Dr. Fraser.

The researchers identified six molecules of importance (CLM-1, IL12RB1, CD83, FAM3B, IGFR1R and OPTC). They found that these molecules were elevated in COVID-19 patients who would become even more severely ill. They found that when measured on a COVID-19 patient's first day of ICU admission, the molecules could be used to predict which patients will survive following standard ICU treatment.

"While further research is needed, we're confident in these biomarkers and suspect these patterns may be present even before ICU admission, such as when a patient first presents to the emergency department," notes Dr. Fraser. "These findings could be incredibly important in determining how severely ill a patient will become."

The team measured 1,161 plasma proteins from the blood of 30 participants: 10 COVID-19 patients and 10 patients with other infections admitted to LHSC's ICU, as well as 10 healthy control participants. Blood was drawn on set days of ICU admission, processed in a lab and then analyzed using statistical methods and artificial intelligence.

The team notes that predicting a patient's disease severity can help in a number of ways. It could allow for medical teams to have important conversations with family members, setting goals of care based on the patient's health and personal wishes. Medical teams could use the knowledge to mobilize resources more quickly. If they know a patient is at higher risk of death, they may consider intervening sooner despite associated risks. The team also hopes the findings can be used to better design COVID-19 clinical trials by grouping patients based on their risk. This could allow for stronger results when examining potential treatments for the disease.

Understanding why blood clots occur and how to treat them

A major complication occurring in most critically ill COVID-19 patients is clotting in the lung's small blood vessels which leads to low oxygen levels in the body.

"The reason for this clotting has been unclear. Most suspect the clotting mechanisms in our blood are put into overdrive and so many clinicians have been treating with anticoagulant therapies like the drug heparin," says Dr. Fraser. "But we've uncovered an entirely different mechanism."

The team further analyzed the blood samples from their 30 participants, and found evidence to suggest that the inner linings of small blood vessels are becoming damaged and inflamed, making them a welcoming environment for platelets (small blood cells) to stick.

They discovered that COVID-19 patients had elevated levels of three molecules (hyaluronic acid, syndecan-1 and P-selectin.) The first two molecules are products broken down from small hair-like structures (the glycocalyx) which line the inside of the blood vessels. Their presence suggests the glycocalyx is being damaged with its breakdown products sent into the bloodstream. The presence of P-selectin is also significant as this molecule helps to make both platelets and the inner lining of blood vessels adhere to one another.

"The glycocalyx keeps platelets from touching the inside wall of the blood vessel and helps facilitate the production of nitric oxide, which has an important role in preventing platelets from sticking," explains Dr. Fraser. "We suspect the body's immune response is producing enzymes that shear off these little hair-like structures, inflaming blood vessels and making them a welcoming environment for platelets to form clots."

The team suggests that two therapies may hold promise for treating blood clots in COVID-19 patients: platelet inhibitors to stop platelets from sticking and molecules to protect and restore the inner lining of blood vessels.

"By exploring these therapies as potential alternatives to anticoagulant therapies, we may be able to improve patient outcomes," says Dr. Fraser. "Through our combined findings, we hope to provide tools to predict which patients will become the most severely ill and treatments for both hyperinflammation and blood clots."

When a star passes too close to a supermassive black hole, tidal forces tear it apart, producing a bright flare of radiation as material from the star falls into the black hole. Astronomers study the light from these "tidal disruption events" (TDEs) for clues to the feeding behavior of the supermassive black holes lurking at the centers of galaxies.

New TDE observations led by astronomers at UC Santa Cruz now provide clear evidence that debris from the star forms a rotating disk, called an accretion disk, around the black hole. Theorists have been debating whether an accretion disk can form efficiently during a tidal disruption event, and the new findings, accepted for publication in the Astrophysical Journal and available online, should help resolve that question, said first author Tiara Hung, a postdoctoral researcher at UC Santa Cruz.

"In classical theory, the TDE flare is powered by an accretion disk, producing x-rays from the inner region where hot gas spirals into the black hole," Hung said. "But for most TDEs, we don't see x-rays--they mostly shine in the ultraviolet and optical wavelengths--so it was suggested that, instead of a disk, we're seeing emissions from the collision of stellar debris streams."

Coauthors Enrico Ramirez-Ruiz, professor of astronomy and astrophysics at UCSC, and Jane Dai at the University of Hong Kong developed a theoretical model, published in 2018, that can explain why x-rays are usually not observed in TDEs despite the formation of an accretion disk. The new observations provide strong support for this model.

"This is the first solid confirmation that accretion disks form in these events, even when we don't see x-rays," Ramirez-Ruiz said. "The region close to the black hole is obscured by an optically thick wind, so we don't see the x-ray emissions, but we do see optical light from an extended elliptical disk."

The telltale evidence for an accretion disk comes from spectroscopic observations. Coauthor Ryan Foley, assistant professor of astronomy and astrophysics at UCSC, and his team began monitoring the TDE (named AT 2018hyz) after it was first detected in November 2018 by the All Sky Automated Survey for SuperNovae (ASAS-SN). Foley noticed an unusual spectrum while observing the TDE with the 3-meter Shane Telescope at UC's Lick Observatory on the night of January 1, 2019.

"My jaw dropped, and I immediately knew this was going to be interesting," he said. "What stood out was the hydrogen line--the emission from hydrogen gas--which had a double-peaked profile that was unlike any other TDE we'd seen."

Foley explained that the double peak in the spectrum results from the Doppler effect, which shifts the frequency of light emitted by a moving object. In an accretion disk spiraling around a black hole and viewed at an angle, some of the material will be moving toward the observer, so the light it emits will be shifted to a higher frequency, and some of the material will be moving away from the observer, its light shifted to a lower frequency.

"It's the same effect that causes the sound of a car on a race track to shift from a high pitch as the car comes toward you to a lower pitch when it passes and starts moving away from you," Foley said. "If you're sitting in the bleachers, the cars on one turn are all moving toward you and the cars on the other turn are moving away from you. In an accretion disk, the gas is moving around the black hole in a similar way, and that's what gives the two peaks in the spectrum."

The team continued to gather data over the next few months, observing the TDE with several telescopes as it evolved over time. Hung led a detailed analysis of the data, which indicates that disk formation took place relatively quickly, in a matter of weeks after the disruption of the star. The findings suggest that disk formation may be common among optically detected TDEs despite the rarity of double-peaked emission, which depends on factors such as the inclination of the disk relative to observers.

"I think we got lucky with this one," Ramirez-Ruiz said. "Our simulations show that what we observe is very sensitive to the inclination. There is a preferred orientation to see these double-peak features, and a different orientation to see x-ray emissions."

He noted that Hung's analysis of multi-wavelength follow-up observations, including photometric and spectroscopic data, provides unprecedented insights into these unusual events. "When we have spectra, we can learn a lot about the kinematics of the gas and get a much clearer understanding of the accretion process and what is powering the emissions," Ramirez-Ruiz said.

LOWELL, Mass. - Incumbent Edward Markey has opened up a double-digit lead over challenger U.S. Rep. Joseph Kennedy III one week before the Democratic primary in the race for U.S. Senate, according to a new poll of Massachusetts voters released today.

Conducted by the UMass Lowell Center for Public Opinion, the poll of 800 likely Democratic primary voters found that Markey leads the race with 52 percent of respondents supporting him, compared to 40 percent for Kennedy, with 6 percent of voters undecided and 2 percent favoring another candidate. The primary election is Tuesday, Sept. 1.

Voters' education factors into their choice and accounts for the largest divide among respondents, poll results show. Voters with a college degree prefer Markey by a 37-point margin, as 65 percent of these respondents would elect him, compared to 28 percent of voters who favor Kennedy. The congressman leads by 15 points among voters without a college degree, with 53 percent favoring him, compared to 38 percent for Markey.

Markey also holds double-digit leads over Kennedy among voters in key demographic groups. Among younger likely voters, 59 percent of respondents age 18 to 44 say they would vote for Markey, compared to 32 percent who would elect Kennedy, giving a 27-point lead in that demographic to the senator, who first won the seat in a 2013 special election to replace former U.S. Sen. John Kerry.

Among women, Markey leads by 18 points, as 55 percent of respondents said they would vote for him, compared to 37 percent for Kennedy. The senator holds a 24-point lead among voters with a family income of more than $100,000, favored by 57 percent of these respondents, compared to 33 percent for Kennedy. The candidates are tied, each with 46 percent support, among respondents who earn less than $50,000 a year. Markey is also besting Kennedy among white voters, as 55 percent of respondents prefer the senator, who holds a 16-point advantage over Kennedy, with 39 percent support. Among voters of color, Kennedy is up one point, 41 percent to Markey's 40 percent, which is within the margin of error.

"Perhaps the most peculiar thing about this race is that the incumbent has been embraced by the outsider wing of the Democratic Party and the challenger has been characterized as an insider. This insider/outsider dynamic comes through clearly in that voters who trust government are much more likely to support Kennedy and those that distrust government are more likely to support Markey. Should Markey hold on to win, his ability to avoid the out-of-touch-establishment-elite label will be the reason he was able to keep his seat," said Joshua Dyck, director of the Center for Public Opinion and UMass Lowell associate professor of political science.

The findings released today are a sharp contrast to the results of past polling by the Center for Public Opinion on the race. Survey results issued in May found a close contest, with Kennedy garnering 44 percent of support among likely Democratic voters and 42 percent supporting incumbent Markey, while 10 percent were undecided. At that time, Markey led among likely voters who identify themselves as liberals (54 percent to 39 percent), while Kennedy was ahead among moderates (55 percent to 25 percent).

Yet despite Markey's widening lead, 52 percent of voters polled in results released today said their lives are not likely to be any better or worse in six years regardless of which candidate wins the election.

"In the final days, voters see this race as low stakes, but that hasn't prevented the race from being high drama. Both candidates have taken the gloves off in this campaign, but it's clear that Markey has Kennedy on the ropes. This bout isn't over, but Markey has the clearest advantage we've seen since Kennedy filed to run," said John Cluverius, associate director of the UMass Lowell Center for Public Opinion and assistant professor of political science.

The poll also surveyed likely Democratic primary voters' views about life during the COVID-19 pandemic. Findings include:

More voters (35 percent), said COVID-19 will prove to be a greater threat to humanity over the next five years than climate change. Thirty-one percent of voters said climate change is the more pressing issue and 36 percent of respondents said the threats were about equal;

Asked whether their local schools should reopen for face-to-face instruction in the fall, 84 percent of voters oppose that move, while 16 percent favor it;

Without an option to vote early or by mail, 15 percent of respondents said they would opt to stay home and not vote in this election. Further, if they knew voting in person would lead to them contracting COVID-19, 62 percent said they would stay home.

"Democratic primary voters have almost no faith in local leaders to safely reopen schools for face-to-face instruction. There's some backlash to President Trump's desire for schools to open in person, but it's clear here that anxiety about reopening schools is rampant among Democratic primary voters, even in a state that has contained the virus much better than others," Cluverius said.

Despite voters' COVID-19 concerns, Massachusetts Republican Gov. Charlie Baker remains extremely popular with Democrats, survey results show. Among poll respondents, Baker has an 89 percent approval rating, with 54 percent of voters who "strongly approve" and 35 percent who "somewhat approve" and only 11 percent who disapprove of how the governor is handling his job. These statistics are virtually unchanged from polling data the Center for Public Opinion released in May, according to Dyck.

"Charlie Baker continues to be the most popular Republican among Democrats in Massachusetts - more popular, in fact, than most Democratic politicians. His 89 percent approval rating among Democratic likely voters includes unenrolled voters. But even among just registered Democrats, Baker's approval rating is 90 percent," he said.

Detailed poll results - including analysis, topline and methodology - are available at http://www.uml.edu/polls. The independent, nonpartisan poll was conducted by the University of Massachusetts Lowell's Center for Public Opinion using the latest technology and highest standards. The center is a member of the American Association for Public Opinion Research's Transparency Initiative and presents events and polls on political and social issues that provide unique opportunities for civic engagement, experiential learning and research.

The poll also surveyed voters' views on national issues. Here, the survey found the Black Lives Matter movement has the support of a majority of Democrats polled, with a net favorability rating of +71 percent. As may be expected among Democratic primary voters, 67 percent of respondents said they disapprove of President Donald Trump's job performance, while 7 percent approve, and 92 percent of voters polled said they think the country is on the wrong track, compared to 8 percent who said it is on the right track.

Findings on the presidential race shows Democratic nominee Joe Biden has a +67 net positive favorability rating, (80 percent favorable, 13 percent unfavorable), while his running mate, U.S. Sen. Kamala Harris has a +65 net positive favorability rating (77 percent favorable, 12 percent unfavorable). On the Republican ticket, Trump has a -87 net negative favorability rating (6 percent favorable, 93 percent unfavorable) and Vice President Mike Pence has a -76 net negative favorability rating (9 percent favorable, 85 percent unfavorable).

Among other national public figures, Dr. Anthony Fauci of the White House coronavirus task force has a +80 net positive favorability rating (85 percent favorable, 5 percent unfavorable) and White House coronavirus adviser Dr. Deborah Birx has a +6 net favorability rating (27 percent favorable, 21 percent unfavorable). Former President Barack Obama has a +81 net positive favorability rating and presidential adviser and son-in-law Jared Kushner is at a -73 net negative rating.

Likely Democratic primary voters were also questioned on a range of other topics. Findings include:

Markey's campaign decision to draw on his roots as an ice cream man may be paying dividends, as the dessert has a net favorability rating of +91 percent among Democrats polled;

Market Basket has a net favorability rating of +68 percent, with Dunkin close behind at +64 percent;

Among companies that operate social-media platforms, TikTok is the most disliked, with a -20 net favorability rating, followed by Facebook with a -4 net favorability rating and Snapchat with a -1 net favorability rating.