Publisher Health

Any future attempts to reduce the spread of covid-19 should be focused on tackling close airborne transmission of the virus which is considered to be the primary route for its circulation, according to experts in an editorial published in The BMJ.
Respiratory experts argue that it is now clear that covid-19 (SARS-CoV-2) is most likely to transmit between people at close range through inhalation rather than through contact with surfaces or longer range airborne routes, although those routes can also be responsible.
The covid-19 pandemic has helped to redefine airborne transmission of viruses, say the experts from the universities of Leicester, Edinburgh Napier and Hong Kong, Virginia Tech, and NHS Lanarkshire, Edinburgh.
There has been some confusion over precise definitions of air transmissions of infections from the last century in which the difference between “droplet” “airborne,” and “droplet nuclei” transmission have led to misunderstandings over the physical behaviour of these particles, they say.
What is important to know, they claim, is that if a person can inhale particles, regardless of their size or name, they are breathing in aerosols. And while this can happen at long range, it is more likely to happen when being close to someone because the aerosols between two people are much more concentrated at short range, similar to being close to someone who is smoking.
People infected with SARS-CoV-2 produce many small respiratory particles full of the virus as they exhale. Some of these will be inhaled almost immediately by those within a typical conversational “short range” distance of less than one metre, say the experts, while the remainder will disperse over longer distances to be inhaled by others further away — more than two metres.

UK adults who are overweight or obese retain their weight over time, which is associated with an increased risk of health complications and death, according to a study published in the open access journal BMC Public Health.
Dr Barbara Iyen, the lead author said: “We have found that despite widespread efforts to prevent and manage obesity, the majority of adults who are overweight or obese in the general population continue to remain so in the long-term. More effective policies and weight-management interventions are needed urgently to address this increasing burden and associated adverse health outcomes.”
Researchers at the University of Nottingham investigated the development of body mass index (BMI) over time. The researchers observed a stable increase in BMI scores across four groups of obese and overweight participants over an average of 10.9 years, with most retaining their degree of obesity long-term.
The authors also found that individuals in the highest BMI group had a three-fold higher risk of heart failure and cardiovascular-disease-related death compared to those in the overweight category. Those in the highest BMI category also had a three-fold higher risk of any health-related death compared to those who were overweight. Participants in the two highest BMI groups did not have an increased risk of stroke or coronary heart disease compared to those who were overweight. The authors found greater levels of socioeconomic deprivation associated with increasing severity of obesity, confirming the need for policies that include vulnerable and disadvantaged groups to tackle obesity.
The study used patient records on 264,230 individuals, collected from 790 general practices between 1999 and 2018, included in the UK Clinical Practice Research Datalink. Participants were divided into four groups, defined by the World Health Organization BMI classifications, as overweight, class-1, class-2 and class-3 obesity.
The authors caution that BMI can vary between sexes and ethnic groups, and body muscle can weigh more than fat giving an incorrect picture of ‘healthy’ weight. However, use of BMI provides routinely available data on weight and weight development that is collected by healthcare professionals. Data on the physical activity levels and dietary intake of participants was lacking in the study. Further research is needed to establish the factors that contribute to weight retention, such as diet and exercise choices, and how social and public health policies can effectively tackle obesity.
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Materials provided by BMC (BioMed Central). Note: Content may be edited for style and length.

Researchers at King’s College London Institute of Psychiatry, Psychology, & Neuroscience, in collaboration with King’s College Hospital NHS Foundation Trust, have found small clusters of cells in the brain that identify locations where tumours could become malignant.
The study, which has been published in Neuro-Oncology Advances today, analysed pieces of living human brain tissue from 20 people undergoing brain tumour surgery at King’s College Hospital, the largest neuro-oncology centre in Europe. The researchers found groups of tumour cells clustered around blood vessels and believe that these sites could be the seedbeds for malignant progression, the process by which a tumour becomes a fast growing and uncontrolled cancer.
To study the brain tissue, neurosurgeons cooled the surface of the brain. They then took a sample and placed it into a cerebrospinal fluid solution. Once it had been transported to the lab, the tissue was then placed into a miniaturised incubation chamber specially designed for this study, where it was bathed in a solution that makes the living tumour cells fluoresce and more easily studied under a microscope.
Dr Gerald Finnerty, Lead author at King’s IoPPN and Honorary Consultant Neurologist at King’s College Hospital said, “This research is hugely significant. The “hotspots” we found exhibited many of the hallmarks of cancer. The ability to pinpoint areas at high risk of malignancy gives us a much better chance of establishing why the brain tumour becomes malignant.”
Brain cancers are difficult to treat because they are so invasive. Even after surgery and chemoradiotherapy there is still a high risk that some cancerous cells can be left behind, increasing the likelihood that the cancer will return. This unfortunately means that many of the young adults it affects do not survive beyond a year.
Dr Alastair Kirby, First author on the study said, “It has been a privilege to work with brain tumour patients and our neurosurgical team to deliver this highly innovative research. Live human brain tissue offers great opportunities to study how a person’s brain tumour responds to treatments. This will revolutionise therapy and bring precision medicine of brain cancer one step closer.”
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Materials provided by King’s College London. Note: Content may be edited for style and length.

Biomedical engineers at Duke University have developed a self-assembling nanomaterial that can help limit damage caused by inflammatory diseases by activating key cells in the immune system. In mouse models of psoriasis, the nanofiber-based drug has been shown to mitigate damaging inflammation as effectively as a gold-standard therapy.
One of the hallmarks of inflammatory diseases, like rheumatoid arthritis, Crohn’s disease and psoriasis, is the overproduction of signaling proteins, called cytokines, that cause inflammation. One of the most significant inflammatory cytokines is a protein called TNF. Currently, the best treatment for these diseases involves the use of manufactured antibodies, called monoclonal antibodies, which are designed to target and destroy TNF and reduce inflammation.
Although monoclonal antibodies have enabled better treatment of inflammatory diseases, the therapy is not without its drawbacks, including a high cost and the need for patients to regularly inject themselves. Most significantly, the drugs also have uneven efficacy, as they may sometimes not work at all or eventually stop working as the body learns to make antibodies that can destroy the manufactured drug.
To circumvent these issues, researchers have been exploring how immunotherapies can help teach the immune system how to generate its own therapeutic antibodies that can specifically limit inflammation.
“We’re essentially looking for ways to use nanomaterials to induce the body’s immune system to become an anti-inflammatory antibody factory,” said Joel Collier, a professor of biomedical engineering at Duke University. “If these therapies are successful, patients need fewer doses of the therapy, which would ideally improve patient compliance and tolerance. It would be a whole new way of treating inflammatory disease.”
In their new paper, which appeared online in the Proceedings of the National Academy of Sciences on April 5, Collier and Kelly Hainline, a graduate student in the Collier lab, describe how novel nanomaterials could assemble into long nanofibers that include a specialized protein, called C3dg. These fibers then were able to activate immune system B-cells to generate antibodies.

Current research on flexible electronics is paving the way for wireless sensors that can be worn on the body and collect a variety of medical data. But where do the data go? Without a similar flexible transmitting device, these sensors would require wired connections to transmit health data.
Huanyu “Larry” Cheng, Dorothy Quiggle Career Development Assistant Professor of Engineering Science and Mechanics in the Penn State College of Engineering, and two international teams of researchers are developing devices to explore the possibilities of wearable, flexible antennae. They published two papers in April in Nano-Micro Letters and Materials & Design.
Wearable antenna bends, stretches, compresses without compromising function
Like wearable sensors, a wearable transmitter needs to be safe for use on human skin, functional at room temperature and able to withstand twisting, compression and stretching. The flexibility of the transmitter, though, poses a unique challenge: When antennae are compressed or stretched, their resonance frequency (RF) changes and they transmit radio signals at wavelengths that may not match those of the antenna’s intended receivers.
“Changing the geometry of an antenna will change its performance,” Cheng said. “We wanted to target a geometric structure that would allow for movement while leaving the transmitting frequency unchanged.”
The research team created the flexible transmitter in layers. Building upon previous research, they fabricated a copper mesh with a pattern of overlapping, wavy lines. This mesh makes up the bottom layer, which touches the skin, and the top layer, which serves as the radiating element in the antenna. The top layer creates a double arch when compressed and stretches when pulled — and moves between these stages in an ordered set of steps. The structured process through which the antenna mesh arches, flattens and stretches improves the overall flexibility of the layer and reduces RF fluctuations between the antenna’s states, according to Cheng.

New research by University of Texas at Dallas scientists could help solve a major challenge in the deployment of certain COVID-19 vaccines worldwide — the need for the vaccines to be kept at below-freezing temperatures during transport and storage.
In a study published online April 13 in Nature Communications, the researchers demonstrate a new, inexpensive technique that generates crystalline exoskeletons around delicate liposomes and other lipid nanoparticles and stabilizes them at room temperature for an extended period — up to two months — in their proof-of-concept experiments.
The Moderna and Pfizer/BioNTech COVID-19 vaccines use lipid nanoparticles — basically spheres of fat molecules — to protect and deliver the messenger RNA that generates a vaccine recipient’s immune response to the SARS-CoV-2 virus.
“The expense of keeping these vaccines very cold from the time they’re made to the time they’re delivered is a challenge that needs to be addressed, especially because many countries don’t have sufficient infrastructure to maintain this kind of cold chain,” said Dr. Jeremiah Gassensmith, associate professor of chemistry and biochemistry and of bioengineering at UT Dallas and a corresponding author of the study. “Although we did not include in this work the specific lipid nanoparticles used in current COVID-19 vaccines, our findings are a step toward stabilizing a lipid nanoparticle in a way that’s never been done before, so far as we know.”
The idea for the research project began during a coffee-break discussion between Gassensmith and Dr. Gabriele Meloni, a corresponding co-author of the study and assistant professor of chemistry and biochemistry in the School of Natural Sciences and Mathematics at UT Dallas.
Gassensmith’s area of expertise is biomaterials and metal-organic frameworks, while Meloni’s research focus is transmembrane transporter proteins. These proteins reside within cell membranes and are crucial for moving a variety of small molecules, including ions and trace metals, in and out of cells for several purposes.

India’s Covid caseload has risen sharply in the past few weeks.The country’s been reporting more than 150,000 cases a day. In January and February daily cases fell below 20,000.So, how did India get from relative calm to its new crisis?Workplaces, markets and malls have reopened, and transport is operating at full capacity. Big weddings, festivals and election rallies are also being held.The result: a situation that one doctor described as a “Covid tsunami”. The BBC’s Vikas Pandey and Anshul Verma report. Additional inputs by BBC Marathi, graphics by Nikita Deshpande. Additional footage from Reuters and Getty.

When a DNA test revealed a decades-old family secret, Maia’s life was turned upside down. What she learned next was even more disturbing.Maia and her sister now believe a fertility doctor used his own sperm to artificially inseminate their mother – and he may be the biological father to many others. This is how her family’s life has changed since the discovery.Video by Angélica M Casas

A 30-year-old man says he “jumped at the chance” when he was offered a Covid-19 jab earlier than expected.Lawrence Dixon, from Cardiff, said he signed up to the reserve list in the morning and received a phone call in the evening asking if he wanted to come down for a vaccine.Dr Emma Ynhell, also 30 and from Cardiff, received the jab after she spotted people “chatting about it on social media” and signed up to the reserve list.Cardiff and Vale health board said it was a mistake that people in their 30s had been offered reserve slots so soon.Although she said it was important no doses of vaccines went to waste, Ms Meredith told BBC Radio Wales that staff had been reminded to give older people the opportunity first.

Keeping the middle seats vacant during a flight could reduce passengers’ exposure to airborne coronavirus by 23 to 57 percent, researchers reported in a new study that modeled how aerosolized viral particles spread through a simulated airplane cabin.But the study may have overestimated the risks of traveling on a fully occupied plane, critics said, because it did not take into account mask-wearing by passengers.“It’s important for us to know how aerosols spread in airplanes,” said Joseph Allen, a ventilation expert at Harvard T.H. Chan School of Public Health who was not involved in the study. But he added, “I’m surprised to see this analysis come out now, making a big statement that middle seats should stay open as a risk-reduction approach, when the model didn’t include the impact of masking. We know that masking is the single most effective measure at reducing emissions of respiratory aerosols.”Although scientists have documented several cases of coronavirus transmission on planes, airplane cabins are generally low-risk environments because they tend to have excellent air ventilation and filtration.Still, concern has swirled around the risk of airplane travel since the pandemic began. Planes are confined environments, and full flights make social distancing impossible. Some airlines began keeping middle seats vacant as a precaution.The new paper, published Wednesday in the Morbidity and Mortality Weekly Report, is based on data collected at Kansas State University in 2017. In that study, the researchers sprayed a harmless aerosolized virus through two mock airplane cabins. (One was a five-row section of an actual single-aisle plane; the other was a mock-up of a double-aisle wide-bodied plane.) The researchers then monitored how the virus dispersed through each cabin.For the new study, researchers from Kansas State and the Centers for Disease Control and Prevention used the 2017 data to model how passengers’ exposure to an airborne virus would change if every middle seat remained open in a 20-row single-aisle cabin.Depending on the specific modeling approach and parameters they used, keeping the middle seats vacant reduced the total exposure passengers experienced in the simulation by 23 to 57 percent, compared with a fully occupied flight.This reduction in risk stemmed from increasing the distance between an infectious passenger and others as well as from reducing the total number of people in the cabin, which lowers the odds that an infectious passenger would be aboard in the first place.The laboratory experiments on virus dispersal in aircraft cabins were conducted several years before the current pandemic began, and did not account for any protection that wearing masks could provide.Masking would reduce the amount of virus that infectious passengers emit into the cabin air and would likely lower the relative benefit of keeping middle seats open, Dr. Allen said.The researchers acknowledge that the study has limitations, but they say that their results suggest that “physical distancing of aircraft passengers, including through policies such as middle-seat vacancy,” could be one of several strategies for reducing air passengers’ exposure to the virus.The cost-benefit analysis is tricky for airlines. But purely from a health perspective, keeping middle seats open would be helpful, providing a buffer between an infectious person and others nearby, according to Alex Huffman, an aerosol scientist at Denver University who was not involved in the study. “Distance matters, for both aerosols and droplets,” he said.