Ultrafast electron dynamics in space and time

Cygnus X-1, a binary star system first discovered in 1964, comprises one of the closest black holes to Earth. New observations of this black hole, the first ever detected, have led astronomers to question what they know about the Universe's most mysterious objects. An international team, including researchers from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC), recently found that the stellar-mass black hole in the Cygnus X-1 binary system has a mass 21 times the mass of the Sun and rotates at a speed close to the speed of light. The study was published in Science on Feb. 18. The researchers used the Very Long Baseline Array - a continent-sized radio ...

Engineers have developed a technique that allows them to precisely place microscopic devices formed from folded DNA molecules in not only a specific location but also in a specific orientation. As a proof-of-concept, they arranged more than 3,000 glowing moon-shaped nanoscale molecular devices into a flower-shaped instrument for indicating the polarization of light. Each of 12 petals pointed in a different direction around the center of the flower, and within in each petal about 250 moons were aligned to the direction of the petal. Because each moon only glows when struck by polarized light matching its orientation, the end result is a flower whose petals light up in sequence as the polarization of light shined upon it is rotated. The flower, which ...

Inhibitors based on approved drugs and designed to disrupt the SARS-CoV-2 viral protein Mpro display strong antiviral activity both in vitro and in a transgenic mouse model, a new study reports. While vaccines are an important tool in the fight against COVID-19, it remains a high priority to develop antiviral drugs, especially with the rise of variants that may partially evade vaccines. The viral protein Mpro is a protease that is required for cleaving precursor polyproteins into functional viral proteins. This essential function makes it a key drug target. Jingxin Qiao et al. designed 32 ...

The COVID-19 pandemic's heavy toll on older Americans highlights the need to strengthen the nation's safety net for people in need of long-term services and supports, an Oregon Health & Science University researcher and co-authors argue in a new report published by Milbank Quarterly. The report proposes a system of universal coverage to support the long-term care of all older Americans. "This approach would protect against financial catastrophe and end the current system that is based on the need to be financially destitute in order to access coverage via Medicaid," ...

BOSTON -- COVID-19, the source of the current pandemic, may be caused by a single virus, but it has a variety of presentations that make treatment difficult. Children, for example, almost exclusively experience mild or asymptomatic COVID-19, while adults can develop severe or even fatal COVID-19. But children who contract COVID-19 are at risk for a rare but serious syndrome called multisystem inflammatory syndrome in children (MIS-C). Severe cases of MIS-C can lead to cardiac disease and ventricular failure, and require hospitalization and intense medical support. Researchers Galit Alter, PhD, core member of the Ragon Institute of MGH, MIT and Harvard, and Lael Yonker, MD, ...

The effects of selective serotonin reuptake inhibitors (SSRIs) and other conventional antidepressants are believed to be based on their increasing the levels of serotonin and noradrenalin in synapses, while ketamine, a new rapid-acting antidepressant, is thought to function by inhibiting receptors for the neurotransmitter glutamate. Neurotrophic factors regulate the development and plasticity of the nervous system. While all antidepressants increase the quantity and signalling of brain-derived neurotrophic factor (BDNF) in the brain, the drugs have so far been thought to act on BDNF indirectly, through serotonin or glutamate receptors. A new study published this week in Cell demonstrates, however, that antidepressants bind directly to a BDNF receptor known as TrkB. This finding challenges ...

NEW YORK, NY (Feb. 18, 2021)--A new study from Columbia University Vagelos College of Physicians and Surgeons has found that suicide mortality can be reduced by a Federally coordinated approach employing scientifically proven options. Columbia researchers J. John Mann, MD, Christina A. Michel, MA, and Randy P. Auerbach, PhD, conducted a systematic review, determining which suicide prevention strategies work and are scalable to national levels. The study, "Improving Suicide Prevention Through Evidence-Based Strategies: A Systematic Review," was published online in the American Journal of Psychiatry. The researchers found that screening school children or the general population for those at risk for suicide--the ...

While the human brain has over 400 miles of total vasculature, little is known about the tiny capillaries that make up much of this intricate labyrinth of blood vessels critical for delivering oxygenated blood and nutrients to billions of brain cells. According to Dr. Andy Shih, a principal investigator in the Center for Developmental Biology and Regenerative Medicine at Seattle Children's Research Institute, understanding how this vast network regulates blood flow in the brain could hold the key to new treatments for neonatal and childhood neurologic conditions, such as stroke and hypoxia, and issues of aging like dementia and Alzheimer's disease. "Insufficient blood flow contributes to many of the common neurologic problems seen in children and adults," he said. "Yet, ...

Acres of asphalt parking lots, unshaded roads, dense apartment complexes and neighborhoods with few parks have taken their toll on the poor. As climate change accelerates, low-income districts in the Southwestern United States are 4 to 7 degrees hotter in Fahrenheit -- on average -- than wealthy neighborhoods in the same metro regions, University of California, Davis, researchers have found in a new analysis. This study provides the most detailed mapping yet of how summer temperatures in 20 urban centers in California, Nevada, Utah, Arizona, Colorado, New Mexico and Texas affected different neighborhoods between 2018 and 2020. The researchers found even greater heat disparities in California than in other states. The largest disparities showed ...

PHILADELPHIA (February 18, 2021) - With stressors mounting daily on the health care system due to the COVID-19 pandemic, a de-prioritization of the childbearing family has been noted. Their care has changed, resulting in mothers forced to go through labor and birth without their partners, parents barred from NICU visitation, and discharge of mothers and newborns early without enough expert lactation care. There is great concern that these changes in childbearing families' care may become permanent - to the detriment of the health of both mother and ...