Culture

DALLAS, March 9, 2020 -- Weight loss, regular physical activity and other lifestyle changes are effective yet underused strategies that should be added to optimize management of atrial fibrillation (an abnormal heart rhythm), according to "Lifestyle and Risk Factor Modification for Reduction of Atrial Fibrillation," a new Scientific Statement from the American Heart Association published today in the Association's flagship journal Circulation.

Atrial fibrillation (AF) is an abnormal heart rhythm that affects at least 2.7 million people in the United States and is increasing as the population grows older. In AF, the upper chambers of the heart, called the atria, beat rapidly and erratically, interfering with proper movement of blood through the chambers, which can allow blood clots to form. Parts of these clots can break off and flow to the brain, causing an ischemic stroke. People who have AF have a five-fold greater risk of having a stroke compared to people without the condition.

To reduce stroke risk in their patients, health professionals use medications or procedures to regulate the heart rate, prevent abnormal heart rhythms (AF) and reduce blood clotting.

"While established medical treatment protocols remain essential, helping AF patients adopt healthier lifestyle habits whenever possible may further help to reduce episodes of AF," said Mina K. Chung, M.D., chair of the writing group for the scientific statement, and a cardiologist and professor of medicine at the Cleveland Clinic.

Weight management with weight loss, nutrition interventions among individuals who are overweight and appropriate, individualized physical activity plans to increase fitness are three lifestyle modifications that have the potential to benefit AF patients.

Obesity can contribute to enlargement and stretching of the heart's upper chambers, changing the way the chambers work and making AF more likely to occur and to be persistent rather than occasional. In an Australian study, people who were overweight or had obesity and lost at least 10% of their body weight were less likely to develop AF or to have it become persistent; and, in some cases, persistent AF became intermittent or disappeared entirely.

In addition, obesity is often associated with sleep apnea, a type of disordered breathing that also raises the risk of AF. Patients with obesity/overweight should be screened for sleep apnea and receive treatment if they have it.

Regular, moderate physical activity does not increase AF risk and may help in preventing and treating the condition. However, the statement notes that extreme levels of physical activity, such as that undertaken by endurance athletes and professional football players, may raise the risk of AF.

"To help patients make healthy lifestyle changes, we suggest setting specific, progressive achievable weight and exercise targets, and prescribing lifestyle intervention programs that can provide appropriate supports. Using a pedometer, smartphone/watch apps or other wearable devices that provide activity feedback, as well as apps that help people track food intake, can be helpful to keep people motivated. Encouragement and reinforcement from the patients' physicians and health care team can also increase patients' dedication," said Chung.

Other lifestyle habits that raise the risk of AF include smoking and moderate or high alcohol use. Smoking not only raises the risk of getting AF, it also reduces the effectiveness of a treatment for AF called ablation (a procedure to destroy cells that generate abnormal rhythms). Patients should be counseled to stop smoking and may be referred to a smoking cessation program.

Studies have also found that moderate or high alcohol use - drinking more than 7 drinks/week in women and 14 drinks/week in men - raises the risk of AF. In a recent study, reducing or abstaining from alcohol was shown to improve heart rhythm control.

Although drinking caffeinated beverages has not been shown to increase the risk of AF, about 1 in 4 people with the condition report that it can trigger an episode according to several studies noted in the statement.

The scientific evidence on lifestyle and AF is limited because the studies on the subject are mostly observational, which can identify links but cannot prove cause and effect.

"We need more research in this area, including randomized trials (which can prove cause and effect) to help determine the effects of and the best ways to achieve long-term, lifestyle and risk factor modification for our patients with AF. In particular, we need further work on the effects of high intensity and other physical activities, and studies on the need for and effects of screening and treating sleep apnea for AF. However, the data emerging support the beneficial effects of lifestyle modification to reduce AF and are a call to action to develop and utilize integrated, multidisciplinary teams and/or structured programs that can facilitate intensive and comprehensive lifestyle counseling for our patients with AF. We encourage health care teams to consider lifestyle interventions in addition to medical management for all patients with AF," said Chung.

Indigenous historian and York University professor Jesse Thistle and Dr. Janet Smylie, a Métis family physician and research chair at Unity Health Toronto and the University of Toronto, who are leading the development of a separate guideline specifically to address Indigenous homelessness, co-authored a related commentary in CMAJ.

In Canada, Indigenous peoples are eight times more likely to be homeless than non-Indigenous people and make up 10%-80% of the total homeless population in large cities. Indigenous-led approaches are needed to address Indigenous homelessness, and Thistle and Smylie have involved Indigenous elders, researchers and scholars, and people with experiences of homelessness to help develop the guideline.

"Central to Indigenous laws governing relationships is the concept of inter-relationality - the notion that all things, animate and inanimate, are connected. Each Indigenous nation has specific protocols or instructions for behaviour that uphold these laws," the authors write.

Although the guideline development process is not yet complete, Thistle and Smylie have identified four broad protocols for health and social service providers working with Indigenous peoples experiencing homelessness: situating one's self, keeoukaywin (visiting), hospitality, and treat people as you would treat your own relative.

"Clinical guideline for homeless and vulnerably housed people, and people with lived homelessness experience" is published March 9, 2020.

New research reveals bias and stereotyping among clinical and research professionals who recruit patients to enroll in cancer clinical trials. The findings are published early online in CANCER, a peer-reviewed journal of the American Cancer Society (ACS).

It is important to include diverse patients in clinical trials to ensure that the results will apply to patients in the general population. Unfortunately, the proportion of racial and ethnic minorities participating in cancer clinical trials is persistently lower than the proportion of minorities in the U.S. population at large.

To examine whether biases held by healthcare and research professionals can help explain why racial and ethnic minorities are not fully represented in clinical trials, a team led by Raegan W. Durant, MD, MPH, of the University of Alabama at Birmingham, conducted interviews of cancer center leaders, principal investigators of clinical trials, referring clinicians, and research staff at five U.S. cancer centers. A total of 91 individuals were interviewed.

Five prominent themes emerged from the interviews:

Respondents noted language barriers and other factors that made communication with potential minority clinical trial participants difficult.

Several respondents stated that they did not perceive potential minority patients to be ideal study candidates after they were screened for cancer clinical trials.

Some respondents described clinicians' time constraints and negative perceptions of minority study participants as challenges.

When respondents discussed clinical trials with minority patients, they often addressed misconceptions to build trust.

For some respondents, race was perceived as irrelevant when screening and recruiting potential minority participants for clinical trials.

"Examples of the stereotypes we observed included perceptions that African Americans were less knowledgeable about cancer research studies, less likely to participate due to altruism, or simply less likely to complete all facets of the research study," said Soumya Niranjan, B Pharm, MS, PhD, the paper's first author, also from the University of Alabama at Birmingham. "These and other examples of bias based on stereotypes of potential minority participants raise concerns that non-whites may be offered fewer opportunities to participate in cancer research studies." She noted that even when research and healthcare professionals use race-neutral stances during clinical trial recruitment, this approach may overlook some of the well-established methods of engaging and recruiting potential minority participants in a culturally tailored manner.

"By no means does this study indicate that all research and healthcare professionals are biased or that all minorities are being deprived of opportunities to participate in cancer research studies," Dr. Durant stressed. "However, the long-term significance of our findings rests in the notion that biases potentially exist in virtually all forms of human interaction, and recruitment for cancer research studies is no exception. Once we acknowledge the potential presence of this bias in this context, we can better identify it, measure it, and begin to think about how best to address it."

Utah residents who have difficulty keeping their families fed could be missing a key ingredient: information. A University of Utah Health study finds that poor communications in at least 22 Utah communities could be hampering efforts to connect those in need with food stamps, food banks, soup kitchens, and other food resources. Researchers say the finding could help refine future community food distribution efforts.

The first-of-its-kind study, which appears in the American Journal of Preventive Medicine, pinpoints previously undetected areas in the state where a lack of information about food banks, soup kitchens, and the Supplemental Nutrition Assistance Program (SNAP)--commonly known as food stamps--is derailing efforts to alleviate food insecurity in Utah. Food insecurity is defined as the limited or uncertain availability of acquiring safe and nutritional food.

"Our findings offer a unique picture of food needs in our state that has been previously available," says Nasser Sharareh, Ph.D., lead author of the study and a postdoctoral research associate in the Department of Population Health Sciences. "It clearly suggests that future efforts to combat food insecurity in Utah should include better use of media and other communications channels to improve awareness of referral services that help people learn more about SNAP and other emergency food providers in their communities."

About one in eight households in Utah struggle to provide food for their families, according to the Food & Research Action Center, a national anti-hunger advocacy group. In October 2019, more than 165,000 Utahans participated in SNAP, according to the U.S. Department of Agriculture.

In the past, accessibility or availability of food resources, such as grocery stores, and the ability of individuals or households to buy that food were two key measures of food insecurity. However, these traditional indicators may not fully reflect the scope of the problem.

To determine what role information--or the lack of it--has on requests for food assistance in the state, Sharareh and his colleagues tracked SNAP enrollment in 99 Utah communities for a year. Then, they correlated that data with food information requests received from those communities by United Way 211 (UW211), a nonprofit emergency services referral hotline.

Using data analysis and a geographic information system (GIS) method, the researchers identified four clusters of communities (total number in parenthesis).

Food Secure (63) - SNAP enrollment and UW211 call rates are both low. Residents likely have little or no need for food assistance programs or information about them. These areas include Park City, St. George, Morgan, and Weber County.

Food Insecure (14) - SNAP enrollment and UW211 call rates are high; residents are in great need of food assistance programs and information about them. These areas include downtown Salt Lake City, Rose Park, and Glendale.

Information Deserts (11) ¬- Low SNAP enrollment but high rate of UW211 calls. Residents might not be aware of SNAP and have little or no knowledge of other community food resources. In these "deserts," UW211 serves as a vital "oasis," referring information-starved callers to community food resources that they were previously unaware of. Areas include Sugar House, The Avenues, Holladay, and West Jordan.

Information Uncertain (11) - High SNAP participation and low rate of UW211 calls. Residents use SNAP but might not be aware of UW211. SNAP alone might be meeting their existing needs. These areas include Carbon, Emery, and San Juan Counties.

The researchers will continue tracking how information availability influences requests for food assistance, particularly in the 22 newly identified information deserts and information uncertain communities that are at high risk of becoming food insecure in the future. In the meantime, the scientists hope their research helps inform public policy decisions regarding food assistance.

"This study offers emergency food providers with a snapshot of where their services are most needed and why they need to bolster their efforts to get timely and reliable information into the hands of those seeking their help," says Andrea Wallace, Ph.D., R.N., the study's senior author and chair of health systems and community-based care in the College of Nursing. "It could lead to policies that help communities better serve residents in need of food assistance, now and in the future."

Based on these findings, the researchers plan to expand their work to identify at-risk communities in more than 15 other states.

In the current study, 36 Utah regions, communities, and neighborhoods were designated as food insecure, information deserts, or information uncertain. They are:

Food Insecure: Ben Lomond, Kearns, Manga, Midvale, Murray, Ogden (downtown), Salt Lake City (downtown, Glendale, Rose Park), South Ogden, South Salt Lake, Taylorsville (east)/Murray (west), West Valley (center), West Valley (east).

Information Deserts: Holladay, Millcreek (south), Sandy, Salt Lake City (The Avenues, Southeast Liberty, Sugar House), Taylorsville (west), West Jordan (northeast, southeast, west/Copperton), West Valley (west).

Information Uncertain: Blanding/Monticello, Carbon County, Cedar City, Daggett and Uintah County, Delta/Fillmore, Emery County, Provo (west city center), Richfield/Monroe/Salina, San Juan County, Washington County.

Researchers at the University of Sydney and University of São Paulo, Brazil, estimate 20 percent of the malaria risk in deforestation hot spots is driven by the international trade of exports including: coffee, timber, soybean, cocoa, wood products, palm oil, tobacco, beef and cotton.

"What does this mean for affluent consumers?" asks senior author Professor Manfred Lenzen, from the Centre for Integrated Sustainability Analysis in the School of Physics at University of Sydney. "We need to be more mindful of our consumption and procurement, and avoid buying from sources implicated with deforestation, and support sustainable land ownership in developing countries."

Previous studies have shown deforestation and rainforest disturbances can increase the transmission of malaria by creating conditions where mosquitoes thrive: warmer habitats and fewer predators.

The study, published in Nature Communications today, is the first to link global demand for goods that increase deforestation to a rise in malaria risk in humans.

"This study is the first to assess the role of global consumption in increasing deforestation and, in turn, malaria risk," said co-author Dr Arunima Malik, from the Centre for Integrated Sustainability Analysis in the School of Physics. "Unsustainable human consumption is clearly driving this trend."

Professor Lenzen said: "Directing consumption away from deforestation has benefits beyond the malaria link; it will help reducing biodiversity loss and greenhouse gas emissions as well."

Direct links

The authors of the study investigated links between the increasing risk of malaria in developing countries to products demanded by distant consumers.

"We achieved this by quantitatively relating malaria incidence first with deforestation, then to primary commodity production, which we then connected to global supply-chain networks and ultimately to worldwide consumer demand," Dr Malik said.

The final step was accomplished by coupling a highly detailed and large international database with an established and widely used analytical technique - multi-region input-output (MRIO) analysis.

"This work goes beyond simple incidence mapping and correlations, in that it unveils a global supply-chain network that links malaria occurring in specific locations because of deforestation with globally dispersed consumption," Dr Malik said.

A call for change

The results of the study can be used for more demand-side approaches to mitigating malaria incidence by focusing on regulating malaria-impacted global supply chains.

Demand-side initiatives such as product labelling and certification, supply-chain dialogue and green procurement standards have been successful in addressing trade-related global problems such as deforestation, threats to species and child labour.

Legal mechanisms can also be a good action to malaria control, said Dr Leonardo Chaves, a co-author of the study, in the Department of Epidemiology, School of Public Health, University of São Paulo, Brazil.

However, in Brazil, the agribusiness sector has criticised environmental legislation that obliges landowners to conserve a proportion of their land with native vegetation.

"If we lose this land to agricultural use we could greatly increase malaria risk, and the bill of each case of malaria in the Amazon is paid by poor and vulnerable families in this region," Dr Chaves said. "Development never reaches the small rural producer; it just makes illness."

Osaka, Japan - Scientists at Osaka University built a new computing device from field-programmable gate arrays (FPGA) that can be customized by the user for maximum efficiency in artificial intelligence applications. Compared with currently used rewireable hardware, the system increases circuit density by a factor of 12. Also, it is expected to reduce energy usage by 80%. This advance may lead to flexible artificial intelligence (AI) solutions that provide enhanced performance while consuming much less electricity.

AI is becoming a part of everyday life for almost all consumers. Ridesharing smartphone apps like Uber, Gmail's spam filters, and smart-home devices like Siri and Nest all rely on AI. However, implementing these algorithms often require a large amount of computing power, which means large electricity bills, as well as big carbon footprints. Systems that could—like the human brain—be rewired to optimize the computer circuitry for each task would provide greatly enhanced energy efficiency.

Normally, we think of hardware, which includes the physical logic gates and transistors of a computer's processor, as fixed by the manufacturer. However, field-programmable gate arrays are specialized logical elements that can be rewired "in the field" by the user for custom logic applications. The research team used non-volatile "via-switches" that remain connected until the user decided to reconfigure them. Using novel nanofabrication methods, they were able to pack twelve times more elements into a grid-like "crossbar" layout. By reducing the distance electronic signals need to be routed, the devices ended up needing 80% less power.

"Our system based on field-programmable gate arrays has a very fast design cycle. It can be reprogrammed daily if desired to get the most computing power for each new AI application," first author Masanori Hashimoto says. The use of via-switches also eliminates the need for the programing silicon area that was necessary in previous FPGA devices.

"Via-switch FPGA is suitable as a high-performance implementation platform of the latest AI algorithms," says senior author Jaehoon Yu.

FAIRFAX, VA - College athletes participating in indoor sports, especially African-Americans, might be vitamin D deficient and put themselves at risk of injury or poor performance according to a study recently published in the journal Nutrients.

George Mason University in Fairfax, Virginia and the Mayo Clinic Health System Sports Medicine Research in Onalaska, Wisconsin conducted this collaborative study. They assessed vitamin D status among basketball players from the George Mason Patriots men's and women's teams. During the 2018-2019 season, players were either allocated a high dose, low dose or no vitamin D, depending on their circulating 25-hydroxyvitamin D levels at the start of the study with the objective to identify the dosage of vitamin D3 supplementation required for optimal status.

According to MayoClinic.org, vitamin D is necessary for building and maintaining healthy bones. Without it, bones can become soft, thin and brittle and can lead to other medical issues down the road including osteoporosis as well as some types of cancer.

"Many athletes are now engaging in supplementation and we don't currently know what the optimal or safe amount of supplementation may be," says Dr. Sina Gallo, assistant professor in Mason's Department of Nutrition and Food Studies. "Prior studies that have addressed this topic typically report data from non-athletic, older populations. Because athletes may not get the necessary vitamin D through natural dietary sources, supplementation offers a safe, affordable, efficacious method to combat deficiencies. This may be particularly beneficial for athletes living at higher latitudes during the winter months."

During the season, players were monitored regularly. Compliance to supplementation was assessed by the athletic trainers designated to each team. Each player's body composition, skin pigmentation, sun exposure, dietary intake, and blood were collected during the study.

"Overall, our findings showed that 13 of the 20 (65%) participants were vitamin D insufficient at baseline," says Dr. Margaret Jones, professor in Mason's School of Kinesiology and sport scientist for the Frank Pettrone Center for Sports Performance. "This result is consistent with a recent systematic review and meta-analysis wherein 56% of a total sample of 2,000 athletes residing in nine different countries including the United States had inadequate levels of vitamin D."

Of those sampled in the study, athletes with darker skin pigmentation exhibited heightened risk of vitamin D insufficiency at baseline, and none of the participants with fair or very fair skin fell into the insufficient category at baseline.

Nicole Sekel led the study for her master of science in nutrition thesis at George Mason University, mentored by Gallo and Jones. Sekel is interested in bone health as well as the optimization of athletic performance through nutritional intervention. She is currently pursuing a PhD in Rehabilitation Science at the University of Pittsburgh.

"Albeit a pilot study with a small sample size to derive from, the current results provide further evidence of the high prevalence of vitamin D insufficiency among a sample of highly-trained, NCAA-DI basketball athletes," says Dr. Andrew Jagim, Sport Medicine Research, Mayo Clinic Health System. "We, as authors, agree that a larger sample is warranted to aid in the development of screening protocols which will enable medical and sports nutrition staff around the country to identify key risk factors of athletes becoming vitamin D deficient."

The human liver carries out a wealth of vital functions through highly coordinated processes involving multiple cell types. However, when the liver is damaged by pharmaceuticals, cholestasis or chronic fat accumulation caused by alcohol or metabolic dysfunction, the various cell types undergo pathological changes and liver function deteriorates. Extensive inflammation severely affects most cellular processes and scar tissue (liver fibrosis) gradually replaces normal liver tissue.

The global prevalence of both liver inflammation and liver fibrosis has taken on pandemic proportions, but still no effective treatment is available. Liver fibrosis may hence develop into cirrhosis and liver cancer with liver transplantation as last resort.

A much better understanding of the cellular dynamics in the healthy and fibrotic liver is therefore essential for the development of diagnostic tools and therapies to timely diagnose and reverse advanced liver fibrosis.

In this project, researchers from University of Southern Denmark used mouse models of liver fibrosis and single-cell RNA sequencing technology to investigate the cellular processes as they change during fibrosis development.

At unprecedented resolution, they have detailed the fibrotic process and the changing interactions between liver cell types. Importantly, top genes found to correlate with liver fibrogenesis in mice turned out to be very accurate in the diagnosis also of human fibrosis.

Key findings are now being validated in studies of human patients aimed at further exploring novel diagnostic markers and identifying possible molecular targets for pharmacological intervention in the fibrotic process.

This validation is part of a larger study, conducted by Center for Functional Genomics and Tissue Plasticity of patients undergoing bariatric surgery. For that study, the researchers are studying liver biopsies taken before and 18 months after surgery to understand, which cell types and genes change and how they change.

While lifestyle choices and genetics go a long way toward predicting longevity, a new study shows that certain community characteristics also play important roles. American communities with more fast food restaurants, a larger share of extraction industry-based jobs, or higher population density have shorter life expectancies, according to researchers from Penn State, West Virginia, and Michigan State Universities. Their findings can help communities identify and implement changes that may promote longer lifespans among their residents.

"American life expectancy recently declined for the first time in decades, and we wanted to explore the factors contributing to this decline. Because of regional variation in life expectancy, we knew community-level factors must matter," said Elizabeth Dobis, a postdoctoral scholar at the Penn State-based Northeast Regional Center for Rural Development (NERCRD), and lead author of the study. "By analyzing place-based factors alongside personal factors, we were able to draw several conclusions about which community characteristics contribute most strongly to this variation in life expectancy."

Life expectancy refers to the length of time a person born in a given year can expect to live. Dobis and her colleagues analyzed on a county-by-county basis how life expectancy in 2014 has changed from a 1980 baseline, using data from more than 3,000 U.S. counties.

They developed a statistical model to determine the relationship between a dozen community variables and each county's 2014 life expectancy, while controlling for personal variables that are known to be important, such as sex, race, education, single-parent status, obesity, and alcohol use.

The community variables they examined included health care access, population growth and density, fast food restaurants, healthy food access, employment by sector, urbanization, and social capital, which measures the networks and bonds providing social cohesion among residents. They looked at each variable in isolation while holding others constant, allowing them to determine which variables independently exert the strongest effect on life expectancy.

The researchers found that a county's 1980 life expectancy value strongly predicted variations in the 2014 value, but it didn't account for all of the variation.

"When we controlled for historical life expectancy, we found three additional community factors that each exert a significant negative effect--a greater number of fast food restaurants, higher population density, and a greater share of jobs in mining, quarrying, and oil and gas extraction," Dobis said. "For example, for every one percentage point increase in the number of fast food restaurants in a county, life expectancy declined by .004 years for men and .006 years for women."

This represents a 15-20 days shorter life span for every man, woman and child in a community, for each 10 percentage point increase in fast food restaurants in a community--or a 150-200 day shorter life span if the number of fast food restaurants were to double.

Similarly, a one percent increase in a county's share of jobs in the mining, quarrying, oil and gas sectors was found to decrease average life expectancy by .04 years for men (or 15 days) and .06 years (22 days) for women.

The research, which was published recently in Social Science and Medicine, also revealed several community factors that are positively related to life expectancy, including a growing population, good access to physicians, and a greater level of social cohesion.

"We were surprised by the strong positive contribution of social capital to life expectancy within communities," said NERCRD Director Stephan Goetz, professor of agricultural economics and regional economics at Penn State and a co-author on the study. "Places with residents who stick together more on a community or social level also appear to do a better of job of helping people in general live longer."

"Another interesting finding was that lower population density, or living in more rural areas, is associated with higher life expectancy," Goetz said. "This suggests that living in large, densely-settled metropolitan areas, with all of their amenities and other advantages, comes at the expense of lower life expectancy, at least in a statistical sense."

In addition to being the first life-expectancy study to include community variables in a county-level analysis, this also was the first study to statistically analyze the extent to which disparities in life expectancy are geographically clustered. This analysis revealed some striking patterns.

"We found exceptionally low life expectancies in the areas of the Pine Ridge and Rosebud Reservations in South Dakota," Dobis said. "We found similar 'cold spots' of low life expectancy in the arctic and interior portions of Alaska, the Deep South surrounding the Mississippi River, and in the Appalachian regions of Kentucky and West Virginia."

The research also revealed four "hot spots" of high life expectancy: a section of the Northeast spanning from Philadelphia to New England, southern Minnesota and the eastern Dakotas into Nebraska, an area in Colorado, and an area spanning central Idaho into the upper Rocky Mountains.

The team's findings have important policy implications, as they suggest that certain aspects of the built environment can be changed to enhance life expectancy. For example, public places that promote social interaction could increase a community's social capital levels, which in turn promote longer lifespans.

Soft and flexible materials can be used to ultrasonically charge bioelectronic implants, which could help to reduce the need for surgical treatment.

Electronic devices are increasingly used to remedy serious and long-term health problems, such as pacemakers to regulate heartbeat, electronic pumps that release insulin, and implantable hearing aids. Key design considerations for these components aim to minimize size and weight for patient comfort, and they ensure that the device is not toxic to the body.

Another stumbling block is how to power the devices. Batteries keep them working for a while, but changing the batteries demands invasive surgery. Ideally, the power source needs to be recharged wirelessly.

A collaborative study between the groups of materials scientist Husam Alshareef at KAUST and medical imaging expert Abdulkader A. Alkenawi at King Saud bin Abdulaziz University for Health Sciences reveals a way to remotely charge a battery using a soft, biocompatible material that absorbs sound waves passed through the body.

Hydrogels are made of long polymer molecules cross-linked to form a three-dimensional network that can hold a great deal of water. This gives hydrogels a flexible and stretchable texture, but it also means they are both electrical conductors and biocompatible, making them ideal for bioelectronic applications.

Kanghyuck Lee, lead author of the study, explains how the team combined polyvinyl alcohol with nanosheets of MXene, a transition-metal carbide, nitride or carbonitride. "Just as dissolving salt in water makes it conductive, we used MXene nanoflakes to create the hydrogel," says Lee. "We were surprised to find that the resulting material can generate electric power under the influence of ultrasound waves."

Their hydrogel, which they refer to as M-gel, generates a current when an applied pressure forces the flow of electrical ions in the water, filling the hydrogel. When this pressure is the result of ultrasound, the effect is called streaming vibration potential.

The KAUST team proved the concept by using a range of ultrasonic sources, including ultrasound tips found in many labs and the ultrasound probes used in hospitals for imaging. They were able to quickly charge an electrical device buried within several centimeters of beef.

"This is another example of the impressive potential of MXene hydrogels we've been developing in our laboratory for sensing and energy applications," said Alshareef.

On 6 March at 11:50 PM EST, the International Space Station resupply mission Space X CRS-20 took off from Cape Canaveral (USA). On board: 250 test tubes from the University of Zurich containing adult human stem cells. These stem cells will develop into bone, cartilage and other organs during the month-long stay in space. Professor Oliver Ullrich and Dr. Cora Thiel, the two research leaders at the UZH Space Hub, are testing their innovative concept of human tissue production in weightlessness for the benefit of transplantation medicine and precision medicine and as an alternative to animal experiments.

Weightlessness as a tool

"We are using weightlessness as a tool," explains Cora Thiel. Physical forces such as gravity influence how stem cells differentiate and how the formation and regeneration of tissue is organized. The researchers assume that due to the low gravity on board the ISS, newly formed cells organize themselves into three-dimensional tissues without an additional matrix or other auxiliary structures. The experiment will take place in a mobile mini-laboratory, the CubeLab module of the US company Space Tango. The module consists of a closed and sterile system, in which the stem cells can proliferate and differentiate at constant temperature.

If the test project is successful, it is planned to gradually switch from a small laboratory to a larger production scale. In the future, the innovative process can be used to generate tissue transplants such as cartilage or new liver cells in space from stem cells which are harvested from individual patients in a routine procedure. According to Oliver Ullrich, an additional application is emerging in precision medicine: "Artificially produced autologous human tissue could be used to determine which combination of drugs is the most suitable for the patient in question. In addition, human tissue and organ-like structures produced in space could help to reduce the number of animal experiments."

Public-private partnership between university and industry

Airbus is also convinced of the potential. The public-private partnership is structured as follows: The Airbus division "Defence and Space" has designed the inlets for the interior of the transport boxes. For their design and manufacture, innovative processes such as selective laser sintering (SLS), a special 3D printing process, were used. The inlets ensure safe transport of the cell samples with maximum volume utilization. In addition, Airbus is organizing access to the ISS, transport of the test tubes to and from the ISS and providing ground support equipment. Ullrich and Thiel are contributing the research idea and study design, and are carrying out the scientific work and providing the scientific staff.

Low Earth Orbit as a future research, development and production location

Contrary to widespread opinion, transportation into space no longer causes costs to skyrocket today. "In space projects, the main cost drivers are the custom-made hardware and the bureaucracy," says Ullrich, Professor of Anatomy at UZH and director of the UZH Space Hub. He therefore deliberately relies on established medical serial products for equipment and instruments. Ullrich is convinced of the future benefits of space flight: "In a few decades, humankind will use the low Earth orbit as a routine place for research, development and production."

Sophia Antipolis, 8 March 2020: Women with heart disease today need flexible options for lifestyle programmes that fit their busy schedules. That's the finding of a study published today, International Women's Day, in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).1

"Women tend to prioritise others before themselves," said senior author Dr. Jennifer Reed of the University of Ottawa Heart Institute, Canada. "The realities of modern life require women to address multiple family, community, social and work-related demands. As a result, many feel they do not have time for cardiac rehabilitation."

Cardiovascular disease is the leading cause of death in women worldwide; in 2015 it accounted for one-third of all female deaths. Following a cardiac event such as a heart attack, patients are advised to attend cardiac rehabilitation for exercise training, lifestyle education, smoking cessation, and psychological support. These programmes improve fitness, quality of life, mental health and survival, and reduce the risk of further events.

However, approximately 10-20% fewer women than men participate in cardiac rehabilitation, and women are more likely to drop out (35% of women quit versus 29% of men). In contrast, women are high users of local exercise classes: many women attend at least 70% of the sessions on offer.

"What lessons can we learn from these community physical activity programmes to increase women's uptake of cardiac rehabilitation? This important question formed the basis of our review," said first author and PhD student Ms. Sol Vidal-Almela of the University of Ottawa Heart Institute.

The authors reviewed a decade of literature to identify what stops women with heart disease from attending cardiac rehabilitation, and the characteristics of local exercise programmes (not specifically targeting people with heart disease) that could overcome those hurdles.

Multiple barriers to participation were identified. Some women view cardiac rehabilitation as a "men's club". Classes are at set times and incompatible with women's daily schedules. Women do not enjoy the physical activity offered and it does not fit their needs: some find it too physically demanding, while others want it to be more challenging. Women frequently lack social support and feel guilty for deserting their family. Classes are often at hospitals far from home; women without a car and poor access to public transportation do not want to inconvenience others to drive them.

Local exercise classes offered different times and types of exercise at convenient locations. The authors identified ways to modernise cardiac rehabilitation and make it more attractive to women:

Offer enjoyable physical activity such as Zumba, soccer, group walking, tai chi, qigong, technology-based balance exercises (e.g. Wii Fit), dancing, and Nordic walking.

Tailor classes to ability: older women may benefit from exercises to help them perform daily activities (e.g. dressing, reaching a cupboard, moving in and out of a chair or bed) and reduce their risk of falls, while younger women may prefer more challenging activities such as high-intensity interval training.

Provide flexible class times that are compatible with women's busy schedules. For example, offer daily exercise sessions and encourage women to attend two to three times a week, or modify the activity depending on the weather (e.g. outdoor walking or indoor DVD dancing).

Hold classes closer to participants' home, workplace or faith-based institution.

Promote social interactions through group activities (e.g. healthy recipe preparation) and allow partners, friends and family members to join in.

Ms. Vidal-Almela said: "We are experiencing a shift in family responsibilities towards more equality, but today's women with heart disease are still more likely to be a caregiver than men. Multiple class options throughout the day may particularly benefit younger women who report lack of time, family and work commitments as barriers to attending cardiac rehabilitation."

Dr. Reed said: "Women's high participation in group exercise classes in their neighbourhood suggests that they enjoy the sense of community. Multi-site cardiac rehabilitation programmes can help to resolve transportation issues and bring a sense of belonging."

She added: "We are more likely to make time for activities we enjoy and consider important. Dance seems a particularly appealing option for women, who find it fun, enjoyable and motivating. With some creativity, we can modernise cardiac rehabilitation to be more appealing and relevant to women."

Dr. Reed concluded: "Women have been underrepresented in cardiovascular research. The assumption that findings from studies predominantly including males will be generalisable to females represents a barrier to the advancement of cardiac rehabilitation to meet the needs of women and men."

A new NASA/university study of carbon dioxide emissions for 20 major cities around the world provides the first direct, satellite-based evidence that as a city's population density increases, the carbon dioxide it emits per person declines, with some notable exceptions. The study also demonstrates how satellite measurements of this powerful greenhouse gas can give fast-growing cities new tools to track carbon dioxide emissions and assess the impact of policy changes and infrastructure improvements on their energy efficiency.

Cities account for more than 70% of global carbon dioxide emissions associated with energy production, and rapid, ongoing urbanization is increasing their number and size. But some densely populated cities emit more carbon dioxide per capita than others.

To better understand why, atmospheric scientists Dien Wu and John Lin of the University of Utah in Salt Lake City teamed with colleagues at NASA's Goddard Space Flight Center in Greenbelt, Maryland and the University of Michigan in Ann Arbor. They calculated per capita carbon dioxide emissions for 20 urban areas on several continents using recently available carbon dioxide estimates from NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite, managed by the agency's Jet Propulsion Laboratory in Pasadena, California. Cities spanning a range of population densities were selected based on the quality and quantity of OCO-2 data available for them. Cities with minimal vegetation were preferred because plants can absorb and emit carbon dioxide, complicating the interpretation of the measurements. Two U.S. cities were included--Las Vegas and Phoenix.

Many scientists and policymakers have assumed the best way to estimate and understand differences in carbon dioxide emissions in major cities is to employ a "bottom-up" approach, compiling an inventory of fossil fuel emissions produced by industrial facilities, farms, road transport and power plants. The bottom-up method was the only feasible approach before remote sensing data sets became available. This approach can provide estimates of emissions by fuel type (coal, oil, natural gas) and sector (power generation, transportation, manufacturing) but can miss some emissions, especially in rapidly developing urban areas.

But for this study, researchers instead employed a "top-down" approach to inventory emissions, using satellite-derived estimates of the amount of carbon dioxide present in the air above an urban area as the satellite flies overhead.

"Other people have used fuel statistics, the number of miles driven by a person or how big people's houses are to calculate per capita emissions," Lin said. "We're looking down from space to actually measure the carbon dioxide concentration over a city."

Published Feb. 20 in the journal Environmental Research Letters, the study found that cities with higher population densities generally have lower per capita carbon dioxide emissions, in line with previous bottom-up studies based on emissions inventories. But the satellite data provided new insights.

"Our motivating question was essentially: When people live in denser cities, do they emit less carbon dioxide? The general answer from our analysis suggests, yes, emissions from denser cities are lower," said Eric Kort, principal investigator and associate professor of climate and space sciences and engineering at the University of Michigan. "It isn't a complete picture, since we only see local direct emissions, but our study does provide an alternative direct observational assessment that was entirely missing before."

The density factor
Scientists have hypothesized that more densely-populated urban areas generally emit less carbon dioxide per person because they are more energy efficient: that is, less energy per person is needed in these areas because of factors like the use of public transportation and the efficient heating and cooling of multi-family dwellings. Satellite data can improve our understanding of this relationship because they describe the combined emissions from all sources. This information can be incorporated with more source-specific, bottom-up inventories to help city managers plan for more energy-efficient growth and develop better estimates of future carbon dioxide emissions.

The OCO-2 data show that not all densely-populated urban areas have lower per capita emissions, however. Cities with major power generation facilities, such as Yinchuan, China, and Johannesburg, had higher emissions than what their population density would otherwise suggest.

"The satellite detects the carbon dioxide plume at the power plant, not at the city that actually uses the power," Lin said.

"Some cities don't produce as much carbon dioxide, given their population density, but they consume goods and services that would give rise to carbon dioxide emissions elsewhere," Wu added.

Another exception to the higher population density/lower emissions observation is affluence. A wealthy urban area, like Phoenix, produces more emissions per capita than a developing city like Hyderabad, India, which has a similar population density. The researchers speculate that Phoenix's higher per capita emissions are due to factors such as higher rates of driving and larger, better air-conditioned homes.

Looking ahead

The researchers stress there's much more to be learned about urban carbon dioxide emissions. They believe new data from OCO-2's successor, OCO-3--which launched to the International Space Station last year--along with future space-based carbon dioxide-observing missions, may shed light on potential solutions to mitigating cities' carbon emissions.

"Many people are interested in carbon dioxide emissions from large cities," Wu said. "Additionally, there are a few places with high emissions that aren't necessarily related to population. Satellites can detect and quantify emissions from those locations around the globe."

Launched in 2014, OCO-2 gathers global measurements of atmospheric carbon dioxide--the principal human-produced driver of climate change--with the resolution, precision and coverage needed to understand how it moves through the Earth system and how it changes over time. From its vantage point in space, OCO-2 makes roughly 100,000 measurements of atmospheric carbon dioxide over the globe every day. JPL manages OCO-2 for NASA's Science Mission Directorate in Washington.

While OCO-2 wasn't optimized to monitor carbon emissions from cities or power plants, it can observe these targets if it flies directly overhead or if the observatory is reoriented to point in their direction. In contrast, OCO-3, which has been collecting daily measurements of carbon dioxide since last summer, features an agile mirror-pointing system that allows it to capture "snapshot maps." In a matter of minutes, it can create detailed mini-maps of carbon dioxide over areas of interest as small as an individual power plant to a large urban area up to 2,300 square miles (6,400 square kilometers), such as the Los Angeles Basin, something that would take OCO-2 several days to do.

For more information on OCO-2 and OCO-3, visit:

https://www.nasa.gov/oco2

https://ocov3.jpl.nasa.gov/

Before the Taqba Dam impounded the Euphrates River in northern Syria in the 1970s, an archaeological site named Abu Hureyra bore witness to the moment ancient nomadic people first settled down and started cultivating crops. A large mound marks the settlement, which now lies under Lake Assad.

But before the lake formed, archaeologists were able to carefully extract and describe much material, including parts of houses, food and tools -- an abundance of evidence that allowed them to identify the transition to agriculture nearly 12,800 years ago. It was one of the most significant events in our Earth's cultural and environmental history.

Abu Hureyra, it turns out, has another story to tell. Found among the cereals and grains and splashed on early building material and animal bones was meltglass, some features of which suggest it was formed at extremely high temperatures -- far higher than what humans could achieve at the time -- or that could be attributed to fire, lighting or volcanism.

"To help with perspective, such high temperatures would completely melt an automobile in less than a minute," said James Kennett, a UC Santa Barbara emeritus professor of geology. Such intensity, he added, could only have resulted from an extremely violent, high-energy, high-velocity phenomenon, something on the order of a cosmic impact.

Based on materials collected before the site was flooded, Kennett and his colleagues contend Abu Hureyra is the first site to document the direct effects of a fragmented comet on a human settlement. These fragments are all part of the same comet that likely slammed into Earth and exploded in the atmosphere at the end of the Pleistocene epoch, according to Kennett. This impact contributed to the extinction of most large animals, including mammoths, and American horses and camels; the disappearance of the North American Clovis culture; and to the abrupt onset of the end-glacial Younger Dryas cooling episode.

The team's findings are highlighted in a paper published in the Nature journal Scientific Reports.

"Our new discoveries represent much more powerful evidence for very high temperatures that could only be associated with a cosmic impact," said Kennett, who with his colleagues first reported evidence of such an event in the region in 2012.

Abu Hureyra lies at the easternmost sector of what is known as the Younger Dryas Boundary (YDB) strewnfield, which encompasses about 30 other sites in the Americas, Europe and parts of the Middle East. These sites hold evidence of massive burning, including a widespread carbon-rich "black mat" layer that contains millions of nanodiamonds, high concentrations of platinum and tiny metallic spherules formed at very high temperatures. The YDB impact hypothesis has gained more traction in recent years because of many new discoveries, including a very young impact crater beneath the Hiawatha Glacier of the Greenland ice sheet, and high-temperature meltglass and other similar evidence at an archaeological site in Pilauco, located in southern Chile.

"The Abu Hureyra village would have been abruptly destroyed," Kennett said. Unlike the evidence from Pilauco, which was limited to human butchering of large animals up to but not younger than the YDB impact burn layer, Abu Hureyra shows direct evidence of the disaster on this early human settlement. An impact or an airburst must have occurred sufficiently close to send massive heat and molten glass over the entire early village, Kennett noted.

The glass was analyzed for geochemical composition, shape, structure, formation temperature, magnetic characteristics and water content. Results from the analysis showed that it formed at very high temperatures and included minerals rich in chromium, iron, nickel, sulfides, titanium and even platinum- and iridium-rich melted iron -- all of which formed in temperatures higher than 2200 degrees Celsius.

"The critical materials are extremely rare under normal temperatures, but are commonly found during impact events," Kennett said. According to the study, the meltglass was formed "from the nearly instantaneous melting and vaporization of regional biomass, soils and floodplain deposits, followed by instantaneous cooling." Additionally, because the materials found are consistent with those found in the YDB layers at the other sites across the world, it's likely that they resulted from a fragmented comet, as opposed to impacts caused by individual comets or asteroids.

"A single major asteroid impact would not have caused such widely scattered materials like those discovered at Abu Hureyra," Kennett said. "The largest cometary debris clusters are proposed to be capable of causing thousands of airbursts within a span of minutes across one entire hemisphere of Earth. The YDB hypothesis proposed this mechanism to account for the widely dispersed coeval materials across more than 14,000 kilometers of the Northern and Southern Hemispheres. Our Abu Hureyra discoveries strongly support a major impact event from such a fragmented comet."

Two factors that control the expression of a key gene required by luminescent bacteria to kill competing bacterial cells have been identified. The finding, by researchers at Penn State, sheds light on the molecular mechanisms that enable different strains of bacteria to compete and establish symbiosis in the Hawaiian bobtail squid. Consequently, the study, which appears online in the Journal of Bacteriology, adds to our understanding of how the make-up of a host's microbiome is determined, and may be applicable to more complex microbiomes in humans.

"We are trying to understand how bacteria interact with one another in the context of an animal-microbe symbiosis," said Tim Miyashiro, assistant professor of biochemistry and molecular biology at Penn State and the leader of the research team. "With many of these symbioses, the surface of the host tissue becomes an ecosystem where the cells of different species and strains of bacteria interact and compete for resources. We knew that some of these bacterial strains have the capacity to attack and kill other strains, but we didn't know how this mechanism is regulated genetically."

When a Hawaiian bobtail squid hatches, bioluminescent bacteria in the surrounding environment begin to colonize tiny recesses called crypts in the squid's light organ. The bacteria find shelter and a nutrient-rich environment within the crypts, where they produce a blue glow that researchers believe helps to obscure the nocturnal squids from predators below. Some strains of this bacteria, Vibrio fischeri, employ a needle-like mechanism known as a type VI secretion system (T6SS) to inject toxins into and kill nearby bacterial cells. Strains that use T6SS will kill susceptible bacterial strains in a crypt, whereas those without T6SS can cohabitate with other strains.

"The type VI system is found within many different bacteria," said Kirsten R. Guckes, a postdoctoral researcher at Penn State and first author of the paper. "It was originally thought to primarily contribute to the virulence of pathogenic bacteria. For example, Vibrio cholerae, the bacteria that causes cholera, uses it. But, we now know that beneficial bacteria, like V. fischeri, also use T6SS to kill other bacteria. Because T6SS is thought to be energetically expensive for the bacteria to produce, and doing so could interfere with the bacteria's ability to thrive and produce bioluminescence, understanding how the components of the system are regulated will help us to explain the host-symbiont relationship and the factors that contribute to establishing symbiosis."

A key structural component of T6SS is Hcp, coded for by two functionally redundant genes. The research team showed that the expression of Hcp is dependent on two factors: the alternative sigma factor σ54 and the bacterial enhancer binding protein VasH. Additionally, they showed that VasH, which is required for the bacteria to kill other cells, regulates Hcp expression within the host, suggesting that the expression of T6SS is regulated during symbiosis.

"The knowledge that the environment of the host can stimulate the type VI system suggests that the system has been integrated into the developmental program that the bacteria use when they initiate symbiosis with the squid," said Miyashiro. "So, it appears that the system is important for the establishment of symbiosis, whether or not other competing bacteria are present. Additionally, we can apply what we are learning in this relatively simple host-symbiont relationship to more complex microbiomes like the ones found in the human gut and on our skin."