Amazing Science

NASA’s Wide Field Infrared Survey Telescope (WFIRST) will find thousands of planets outside our solar system, known as exoplanets. Studying the properties of exoplanet worlds will help us understand what planetary systems throughout the Milky Way are like and how planets form and evolve.

NASA’s Kepler and Transiting Exoplanet Survey Satellite (TESS) missions will complete the first planet census that is sensitive to a wide range of planet masses and orbits, bringing us a step closer to discovering habitable Earth-like worlds beyond our own.

To date, astronomers have found most planets when they pass in front of their host star in events called transits, which temporarily dim the star's light. WFIRST data can spot transits too, but the mission will primarily watch for the opposite effect — little surges of radiance produced by a light-bending phenomenon called microlensing. These events are much less common than transits because they rely on the chance alignment of two widely separated and unrelated stars drifting through space.

"Microlensing signals from small planets are rare and brief, but they’re stronger than the signals from other methods,” said David Bennett, who leads the gravitational microlensing group at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Since it’s a one-in-a-million event, the key to WFIRST finding low-mass planets is to search hundreds of millions of stars.”

In addition, microlensing is better at finding planets in and beyond the habitable zone — the orbital distances where planets might have liquid water on their surfaces.

Microlensing 101

This effect occurs when light passes near a massive object. Anything with mass warps the fabric of space-time, sort of like the dent a bowling ball makes when set on a trampoline. Light travels in a straight line, but if space-time is bent — which happens near something massive, like a star — light follows the curve.

Any time two stars align closely from our vantage point, light from the more distant star curves as it travels through the warped space-time of the nearer star. This phenomenon, one of the predictions of Einstein’s general theory of relativity, was famously confirmed by British physicist Sir Arthur Eddington during a total solar eclipse in 1919. If the alignment is especially close, the nearer star acts like a natural cosmic lens, focusing and intensifying light from the background star.

Planets orbiting the foreground star may also modify the lensed light, acting as their own tiny lenses. The distortion they create allows astronomers to measure the planet’s mass and distance from its host star. This is how WFIRST will use microlensing to discover new worlds.

Old human cells return to a more youthful and vigorous state after being induced to briefly express a panel of proteins involved in embryonic development, according to a new study by researchers at the Stanford University School of Medicine. The researchers also found that elderly mice regained youthful strength after their existing muscle stem cells were subjected to the rejuvenating protein treatment and transplanted back into their bodies.

The proteins, known as Yamanaka factors, are commonly used to transform an adult cell into what are known as induced pluripotent stem cells, or iPS cells. Induced pluripotent stem cells can become nearly any type of cell in the body, regardless of the cell from which they originated. They've become important in regenerative medicine and drug discovery.

The study found that inducing old human cells in a lab dish to briefly express these proteins rewinds many of the molecular hallmarks of aging and renders the treated cells nearly indistinguishable from their younger counterparts.

"When iPS cells are made from adult cells, they become both youthful and pluripotent," said Vittorio Sebastiano, PhD, assistant professor of obstetrics and gynecology and the Woods Family Faculty Scholar in Pediatric Translational Medicine. "We've wondered for some time if it might be possible to simply rewind the aging clock without inducing pluripotency. Now we've found that, by tightly controlling the duration of the exposure to these protein factors, we can promote rejuvenation in multiple human cell types."

Sebastiano is the senior author of the study, which will be published online March 24 in Nature Communications. Former graduate student Tapash Sarkar, PhD, is the lead author of the article. "We are very excited about these findings," said study co-author Thomas Rando, MD, PhD, professor of neurology and neurological sciences and the director of Stanford's Glenn Center for the Biology of Aging. "My colleagues and I have been pursuing the rejuvenation of tissues since our studies in the early 2000s revealed that systemic factors can make old tissues younger. In 2012, Howard Chang and I proposed the concept of using reprogramming factors to rejuvenate cells and tissues, and it is gratifying to see evidence of success with this approach." Chang, MD, PhD, is a professor of dermatology and of genetics at Stanford.

Most of the laws of physics don't care which direction time is travelling. Forwards, backwards… either way, the laws work exactly the same. Newtonian physics, general relativity - time is irrelevant to the mathematics: This is called time-reversal symmetry.

In the real Universe, things get a bit messier. And now a team of scientists led by astronomer Tjarda Boekholt of the University of Aveiro in Portugal have shown that it takes as few as three gravitationally interacting bodies to break time-reversal symmetry. "Hitherto, a quantitative relation between chaos in stellar dynamical systems and the level of irreversibility remained undetermined," they wrote in their paper.

"In this work we study chaotic three-body systems in free fall initially using the accurate and precise n-body code Brutus, which goes beyond standard double-precision arithmetic. We demonstrate that the fraction of irreversible solutions decreases as a power law with numerical accuracy."

When running n-body simulations, physicists sometimes return time-irreversibility in their results - in other words, running the simulations backwards doesn't get them to the original starting point.

What has been unclear is whether this is a result of the chaos of these systems, or problems with the simulations, leading to uncertainty over their reliability. So, Boekholt and his colleagues designed a test to figure this out. He and computational astrophysicist Simon Portegies Zwart of Leiden University in the Netherlands previously wrote an n-body simulation code called Brutus that uses brute-force computing power to reduce the magnitude of numerical errors.

Now, they have used it to test the time-reversibility of a three-body system. "Since Newton's equations of motion are time reversible, a forward integration followed by a backward integration of the same time should recover the initial realisation of the system (albeit with a sign difference in the velocities)," they wrote in their paper. "The outcome of a reversibility test is thus exactly known."

They found that, 5 percent of the time, the simulation could not be reversed. All it took was a disturbance to the system the size of a Planck length, which  is the smallest length possible.

"The movement of the three black holes can be so enormously chaotic that something as small as the Planck length will influence the movements," Boekholt said. "The disturbances the size of the Planck length have an exponential effect and break the time symmetry."

Five percent may not seem like much, but since you can never predict which of your simulations will fall within that five percent, the researchers have concluded that n-body systems are therefore "fundamentally unpredictable". And they have shown that the problem is not with the simulations after all.

"Not being able to turn back time is no longer just a statistical argument," Portegies Zwart said. "It is already hidden in the basic laws of nature. Not a single system of three moving objects, big or small, planets or black holes, can escape the direction of time."

A drug combo already used against HIV. A malaria treatment first tested during World War II. A new antiviral whose promise against Ebola fizzled last year.

Could any of these drugs hold the key to saving coronavirus disease 2019 (COVID-19) patients from serious harm or death? On Friday, the World Health Organization (WHO) announced a large global trial, called SOLIDARITY, to find out whether any can treat infections with the new coronavirus for the dangerous respiratory disease. It’s an unprecedented effort—an all-out, coordinated push to collect robust scientific data rapidly during a pandemic. The study, which could include many thousands of patients in dozens of countries, has been designed to be as simple as possible so that even hospitals overwhelmed by an onslaught of COVID-19 patients can participate.

With about 15% of COVID-19 patients suffering from severe disease and hospitals being overwhelmed, treatments are desperately needed. So rather than coming up with compounds from scratch that may take years to develop and test, researchers and public health agencies are looking to repurpose drugs already approved for other diseases and known to be largely safe. They’re also looking at unapproved drugs that have performed well in animal studies with the other two deadly coronaviruses, which cause severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).

Drugs that slow or kill the novel coronavirus, called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), could save the lives of severely ill patients, but might also be given prophylactically to protect health care workers and others at high risk of infection. Treatments may also reduce the time patients spend in intensive care units, freeing critical hospital beds.

Scientists have suggested dozens of existing compounds for testing, but WHO is focusing on what it says are the four most promising therapies: an experimental antiviral compound called remdesivir; the malaria medications chloroquine and hydroxychloroquine; a combination of two HIV drugs, lopinavir and ritonavir; and that same combination plus interferon-beta, an immune system messenger that can help cripple viruses. Some data on their use in COVID-19 patients have already emerged—the HIV combo failed in a small study in China—but WHO believes a large trial with a greater variety of patients is warranted.

Enrolling subjects in SOLIDARITY will be easy. When a person with a confirmed case of COVID-19 is deemed eligible, the physician can enter the patient’s data into a WHO website, including any underlying condition that could change the course of the disease, such as diabetes or HIV infection. The participant has to sign an informed consent form that is scanned and sent to WHO electronically. After the physician states which drugs are available at his or her hospital, the website will randomize the patient to one of the drugs available or to the local standard care for COVID-19.

“After that, no more measurements or documentation are required,” says Ana Maria Henao Restrepo, a medical officer at WHO’s Emergencies Programme. Physicians will record the day the patient left the hospital or died, the duration of the hospital stay, and whether the patient required oxygen or ventilation, she says. “That’s all.”

Three new species of toothed pterosaurs — flying reptiles of the Cretaceous period, some 100 million years ago — have been identified in Africa by an international team of scientists led by Baylor University.

Even a perfect response from government and citizen won’t end the pandemic. As long as the virus persists somewhere, there’s a chance that one infected traveler will reignite fresh sparks in countries that have already extinguished their fires. This is already happening in China, Singapore, and other Asian countries that briefly seemed to have the virus under control. Under these conditions, there are three possible endgames: one that’s very unlikely, one that’s very dangerous, and one that’s very long.

The first is that every nation manages to simultaneously bring the virus to heel, as with the original SARS in 2003. Given how widespread the coronavirus pandemic is, and how badly many countries are faring, the odds of worldwide synchronous control seem vanishingly small.

The second scenario is that the virus does what past flu pandemics have done: It burns through the world and leaves behind enough immune survivors that it eventually struggles to find viable hosts. This “herd immunity” scenario would be quick, and thus tempting. But it would also come at a terrible cost: SARS-CoV-2 is more transmissible and fatal than the flu, and it would likely leave behind many millions of corpses and a trail of devastated health care systems. The United Kingdom initially seemed to consider this herd immunity strategy, before backtracking when models revealed the dire consequences of it. The U.S. now seems to be considering it too.

The third scenario is that the world plays a protracted game of whack-a-mole with the virus, stamping out outbreaks here and there until a vaccine can be found and mass-produced. This is the best option, but also the longest and most complicated one.

It depends, for a start, on making a vaccine. If this were a flu pandemic, vaccine development would be easier. The world is experienced at making flu vaccines and does so every year. But there are no existing vaccines for coronaviruses—until now, these viruses seemed to cause diseases that were mild or rare—so researchers must start from scratch. The first steps have been impressively quick. Just recently, a possible vaccine created by Moderna and the National Institutes of Health (NIH) went into early clinical testing. That marks a 63-day gap between scientists sequencing the virus’ genes for the first time and doctors injecting a vaccine candidate into a person’s arm. “It’s overwhelmingly a world record,” Dr. Fauci said.

But it’s also the fastest step among many subsequent slow ones. The initial trial will simply tell researchers if the vaccine seems safe, and if it can actually mobilize the immune system. Researchers will then need to check that it actually prevents infection from SARS-CoV-2. They’ll need to do animal tests and large-scale trials to ensure that the vaccine doesn’t cause severe side effects. They’ll need to work out what dose is required, how many shots people need, whether the vaccine works in elderly people, and whether it requires other chemicals to boost its effectiveness.

“Even if it works, they don’t have an easy way to manufacture it at a massive scale,” said Seth Berkley of Gavi. That’s because Moderna is using a new approach to vaccination. Existing vaccines work by providing the body with inactivated or fragmented viruses, allowing the immune system to prep its defenses ahead of time. By contrast, Moderna’s vaccine comprises a sliver of SARS-CoV-2’s genetic material—its RNA. The idea is that the body can use this sliver to build its own viral fragments, which would then form the basis of the immune system’s preparations. This approach works in animals, but is unproven in humans. By contrast, French scientists are trying to modify the existing measles vaccine using fragments of the new coronavirus. “The advantage of that is that if we needed hundreds of doses tomorrow, a lot of plants in the world know how to do it,” Berkley said. No matter which strategy is faster, Berkley and others estimate that it will take 12 to 18 months to develop a proven vaccine, and then longer still to make it, ship it, and inject it into people’s arms.

It’s likely, then, that the new coronavirus will be a lingering part of American life for at least a year, if not much longer. If the current round of social-distancing measures works, the pandemic may ebb enough for things to return to a semblance of normalcy. Offices could fill and bars could bustle. Schools could reopen and friends could reunite. But as the status quo returns, so too will the virus. This doesn’t mean that society must be on continuous lockdown until 2022. But “we need to be prepared to do multiple periods of social distancing,” says Stephen Kissler of Harvard.

Much about the coming years, including the frequency, duration, and timing of social upheavals, depends on two properties of the virus, both of which are currently unknown. First: seasonality. Coronaviruses tend to be winter infections that wane or disappear in the summer. That may also be true for SARS-CoV-2, but seasonal variations might not sufficiently slow the virus when it has so many immunologically naïve hosts to infect. “Much of the world is waiting anxiously to see what—if anything—the summer does to the SARS-CoV-2 transmission in the Northern Hemisphere,” says Maia Majumder of Harvard Medical School and Boston Children’s Hospital.

Hayley Clissold from the Sanger Institute's policy team team explores the issues surrounding gene editing and human embryos.

Genome editing is a technique used to modify a specific section of DNA. As all living things contain DNA, genome editing has an almost unlimited range of applications in organisms including bacteria, plants, animals and humans.

Genome editing is not a new technology. In fact, it has been around for decades. Genome editing has only recently taken the scientific world by storm because of the discovery of a new tool called CRISPR. CRISPR is simpler, faster, cheaper and much more efficient than any of its predecessor genome editing tools and because of its accessibility, CRISPR is now used in a vast spectrum of applications in labs all around the world.

CRISPR was originally discovered as a bacterial immune system. Some bacteria deploy CRISPR as a defense mechanism to chop up the DNA of an invading virus. Because of its ability to target and cut specific stretches of DNA, CRISPR is capable of removing any particular sequence – for example, disease-causing gene variants can be taken out of a genome. The technology also allows DNA sequences to be added or changed – so a disease-causing variant can be replaced with a ‘healthy’ one. Clearly, this technology offers almost limitless possibilities for science and in particular for healthcare.

Germline vs somatic editing

Human cells are categorized as either a somatic cell or a germline cell. Germline cells are the reproductive cells (sperm or eggs) and somatic (body) cells are all the other ones (e.g. skin cells, liver cells, immune cells etc). Germline cells pass on their DNA to future generations.

Opinions towards genome editing differ depending upon whether the DNA modification occurs in a somatic cell or a germline cell. Editing DNA in somatic cells is more widely accepted largely because the modifications will only affect the treated individual and will not be inherited by future descendants. In fact, some cancer patients in the UK have already been treated by somatic genome editing and there are several ongoing clinical trials testing this technology for an array of other life-threatening and debilitating disorders. However, there are greater concerns over the use of genome editing in germline cells, because any modification to the genome could be irreversibly inherited by future generations.

Most ordinary matter is held together by an invisible subatomic glue known as the strong nuclear force — one of the four fundamental forces in nature, along with gravity, electromagnetism, and the weak force. The strong nuclear force is responsible for the push and pull between protons and neutrons in an atom’s nucleus, which keeps an atom from collapsing in on itself.

In atomic nuclei, most protons and neutrons are far enough apart that physicists can accurately predict their interactions. However, these predictions are challenged when the subatomic particles are so close as to be practically on top of each other.

While such ultrashort-distance interactions are rare in most matter on Earth, they define the cores of neutron stars and other extremely dense astrophysical objects. Since scientists first began exploring nuclear physics, they have struggled to explain how the strong nuclear force plays out at such ultrashort distances.

Now physicists at MIT and elsewhere have for the first time characterized the strong nuclear force, and the interactions between protons and neutrons, at extremely short distances.

They performed an extensive data analysis on previous particle accelerator experiments, and found that as the distance between protons and neutrons becomes shorter, a surprising transition occurs in their interactions. Where at large distances, the strong nuclear force acts primarily to attract a proton to a neutron, at very short distances, the force becomes essentially indiscriminate: Interactions can occur not just to attract a proton to a neutron, but also to repel, or push apart pairs of neutrons.

“This is the first very detailed look at what happens to the strong nuclear force at very short distances,” says Or Hen, assistant professor of physicst at MIT. “This has huge implications, primarily for neutron stars and also for the understanding of nuclear systems as a whole.”

Hen and his colleagues have published their results today in the journal Nature. His co-authors include first author Axel Schmidt PhD ’16, a former graduate student and postdoc, along with graduate student Jackson Pybus, undergraduate student Adin Hrnjic and additional colleagues from MIT, the Hebrew University, Tel-Aviv University, Old Dominion University, and members of the CLAS Collaboration, a multi-institutional group of scientists involved with the CEBAF Large Accelerator Spectrometer (CLAS), a particle accelerator at Jefferson Laboratory in Newport News, Virginia.

Ultra-short-distance interactions between protons and neutrons are rare in most atomic nuclei. Detecting them requires pummeling atoms with a huge number of extremely high-energy electrons, a fraction of which might have a chance of kicking out a pair of nucleons (protons or neutrons) moving at high momentum — an indication that the particles must be interacting at extremely short distances.

“To do these experiments, you need insanely high-current particle accelerators,” Hen says. “It’s only recently where we have the detector capability, and understand the processes well enough to do this type of work.”

Hen and his colleagues looked for the interactions by mining data previously collected by CLAS, a house-sized particle detector at Jefferson Laboratory; the JLab accelerator produces unprecedented high intensity and high-energy beams of electrons. The CLAS detector was operational from 1988 to 2012, and the results of those experiments have since been available for researchers to look through for other phenomena buried in the data.

In their new study, the researchers analyzed a trove of data, amounting to some quadrillion electrons hitting atomic nuclei in the CLAS detector. The electron beam was aimed at foils made from carbon, lead, aluminum, and iron, each with atoms of varying ratios of protons to neutrons. When an electron collides with a proton or neutron in an atom, the energy at which it scatters away is proportional to the energy and momentum of the corresponding nucleon.

“If I know how hard I kicked something and how fast it came out, I can reconstruct the initial momentum of the thing that was kicked,” Hen explains.

With this general approach, the team looked through the quadrillion electron collisions and managed to isolate and calculate the momentum of several hundred pairs of high-momentum nucleons. Hen likens these pairs to “neutron star droplets,” as their momentum, and their inferred distance between each other, is similar to the extremely dense conditions in the core of a neutron star.

They treated each isolated pair as a “snapshot” and organized the several hundred snapshots along a momentum distribution. At the low end of this distribution, they observed a suppression of proton-proton pairs, indicating that the strong nuclear force acts mostly to attract protons to neutrons at intermediate high-momentum, and short distances.

Further along the distribution, they observed a transition: There appeared to be more proton-proton and, by symmetry, neutron-neutron pairs, suggesting that, at higher momentum, or increasingly short distances, the strong nuclear force acts not just on protons and neutrons, but also on protons and protons and neutrons and neutrons. This pairing force is understood to be repulsive in nature, meaning that at short distances, neutrons interact by strongly repelling each other.

“This idea of a repulsive core in the strong nuclear force is something thrown around as this mythical thing that exists, but we don’t know how to get there, like this portal from another realm,” Schmidt says. “And now we have data where this transition is staring us in the face, and that was really surprising.”

The researchers believe this transition in the strong nuclear force can help to better define the structure of a neutron star. Hen previously found evidence that in the outer core of neutron stars, neutrons mostly pair with protons through the strong attraction. With their new study, the researchers have found evidence that when particles are packed in much denser configurations and separated by shorter distances, the strong nuclear force creates a repulsive force between neutrons that, at a neutron star’s core, helps keep the star from collapsing in on itself.

In a new study appearing in this week’s issue of Proceedings of the National Academy of Sciences (PNAS), a team of Carnegie Mellon University researchers show for the first time how important evolutionary adaptations are in predicting epidemics.

When scientists try to predict the spread of something across populations -- anything from a coronavirus to misinformation -- they use complex mathematical models to do so. Typically, they'll study the first few steps in which the subject spreads, and use that rate to project how far and wide the spread will go. But what happens if a pathogen mutates, or information becomes modified, changing the speed at which it spreads? In a new study appearing in this week's issue of Proceedings of the National Academy of Sciences (PNAS), a team of Carnegie Mellon University researchers show for the first time how important these considerations are.

"These evolutionary changes have a huge impact," says CyLab faculty member Osman Yagan, an associate research professor in Electrical and Computer Engineering (ECE) and corresponding author of the study. "If you don't consider the potential changes over time, you will be wrong in predicting the number of people that will get sick or the number of people who are exposed to a piece of information."

Most people are familiar with epidemics of disease, but information itself -- nowadays traveling at lightning speeds over social media -- can experience its own kind of epidemic and "go viral." Whether a piece of information goes viral or not can depend on how the original message is tweaked.

"Some pieces of misinformation are intentional, but some may develop organically when many people sequentially make small changes like a game of 'telephone,'" says Yagan. "A seemingly boring piece of information can evolve into a viral Tweet, and we need to be able to predict how these things spread."

In their study, the researchers developed a mathematical theory that takes these evolutionary changes into consideration. They then tested their theory against thousands of computer-simulated epidemics in real-world networks, such as Twitter for the spread of information or a hospital for the spread of disease.

In the context of spreading of infectious disease, the team ran thousands of simulations using data from two real-world networks: a contact network among students, teachers, and staff at a US high school, and a contact network among staff and patients in a hospital in Lyon, France.

These simulations served as a test bed: the theory that matches what is observed in the simulations would prove to be the more accurate one. "We showed that our theory works over real-world networks," says the study's first author, Rashad Eletreby, who was a Carnegie Mellon Ph.D. student when he wrote the paper. "Traditional models that don't consider evolutionary adaptations fail at predicting the probability of the emergence of an epidemic."

Since the late 19th century, scientists have understood that, when heated, all materials emit light in a predictable spectrum of wavelengths. Research published today in Nature Scientific Reports presents a material that emits light when heated that appears to exceed the limits set by that natural law.

Could there be a new kind of light in the universe? Since the late 19th century, scientists have understood that, when heated, all materials emit light in a predictable spectrum of wavelengths. Research published today in Nature Scientific Reports presents a material that emits light when heated that appears to exceed the limits set by that natural law.

In 1900, Max Planck first mathematically described a pattern of radiation and ushered in the quantum era with the assumption that energy can only exist in discrete values. Just as a fireplace poker glows red hot, increasing heat causes all materials to emit more intense radiation, with the peak of the emitted spectrum shifting to longer wavelengths as heat rises. In keeping with Planck's Law, nothing can emit more radiation than a hypothetical object that absorbs energy perfectly, a so-called "blackbody."

The new material discovered by Shawn Yu Lin, lead author and a professor of physics at Rensselaer Polytechnic Institute, defies the limits of Planck's law, emitting a coherent light similar to that produced by lasers or LEDs, but without the costly structure needed to produce the stimulated emission of those technologies. In addition to the spectroscopy study just published in Nature Scientific Reports, Lin previously published an imaging study in IEEE Photonics Journal. Both show a spike in radiation at about 1.7 microns, which is the near-infrared portion of the electromagnetic spectrum.

"These two papers offer the most convincing evidence of 'super-Planckian' radiation in the far-field," said Lin. "This doesn't violate Planck's law. It's a new way to generate thermal emission, a new underlying principle. This material, and the method that it represents, opens a new path to realize super-intense, tunable LED-like infrared emitters for thermophotovoltaics and efficient energy applications."

For his research, Lin built a three-dimensional tungsten photonic crystal -- a material that can control the properties of a photon -- with six offset layers, in a configuration similar to a diamond crystal, and topped with an optical cavity that further refines the light. The photonic crystal shrinks the spectrum of light that is emitted from the material to a span of about 1 micrometer. The cavity continues to squeeze the energy into a span of roughly 0.07 micrometers.

Lin has been working to establish this advance for 17 years, since he created the first all-metallic photonic crystal in 2002, and the two papers represent the most rigorous tests he has conducted. "Experimentally, this is very solid, and as an experimentalist, I stand by my data. From a theoretical perspective, no one yet has a theory to fully explain my discovery," Lin said.

The symptoms suggest SARS-CoV-2 might infect neurons, raising questions about whether there could be effects on the brain that play a role in patients’ deaths, but the data are preliminary.

Because COVID-19 has symptoms similar to the flu, much of the attention could get diverted towards the pulmonary aspect of SARS-CoV-2, while neural involvement may remain covert. When a patient begins to exhibit severe neurological symptoms, such as a loss of involuntary breathing, it may be too late to prevent fatalities.

In a recent review article, Yan-Chao Li of Jilin University in China and colleagues argue that if SARS-CoV-2 infects nerve cells, particularly neurons in the medulla oblongata, which is part of the brain stem that serves as the control center for the heart and the lungs, the damage could contribute to “acute respiratory failure of patients with COVID-19.” 

The epidemiological evidence supports the hypothesis that neurons in the medulla can become infected with SARS-CoV-2 and contribute to a patient’s breathing problems and potential death. Li and colleagues explain that the time it takes for COVID-19 to progress from first symptoms to difficulty breathing is typically five days; patients are then admitted to the hospital roughly two days later, and a day after that put into intensive care. “The latency period is enough for the virus to enter and destroy the medullary neurons,” they write.

SARS-CoV-2 enters human cells using a receptor called ACE2. Researchers have reported that ACE2 regulates cardiovascular function, and according to a search of protein databases, many human cell types express ACE2, including lung, heart, kidney, intestine, and brain tissue. There are also multiple ways that the virus could invade the central nervous system: It might circulate through the blood and then attack ACE2 receptors in the endothelia that lines blood capillaries in the brain, breaching the blood-brain barrier and invading neurons through that route. A breached blood-brain barrier could also cause brain swelling, compressing the brain stem and affecting respiration. The cells innervating the lungs could also become infected, making involuntary respiration more difficult.

Evidence from experiments in mice also suggest that the virus might target the nervous system through the olfactory bulb. In a 2008 study, immunologist Stanley Perlman of the University of Iowa and colleagues showed that SARS-CoV—the virus that caused the SARS outbreak that killed more than 770 people in 2003—entered the brains of transgenic mice expressing human ACE2 through neurons in the nose. The virus then rapidly spread to connecting nerve cells. The extensive nerve damage was the major cause of death, the team reported, even though low levels of the virus were detected in the animals’ lungs.

Although this has not been demonstrated, SARS-CoV-2 could potentially enter the nervous system through the olfactory bulb, as SARS-CoV does in mice. “Death of the animal likely results from dysfunction and/or death of infected neurons, especially those located in cardiorespiratory centers in the medulla,” the team wrote. A study with the MERS virus in mice expressing ACE2 showed a similar result, Perlman tells The Scientist. “The brain certainly can be readily infected in mice,” he notes. “Whether this occurs in humans to any great extent is really unknown, but not very likely at this point,” given how much larger rodents’ olfactory bulbs are relative to the overall size of their brains compared with humans’ and the paucity of evidence in humans.

Further Reading: “Can Viruses Cause Neurodegeneration?”

A nest is “a disordered stick bomb,” resilient in ways that humans have hardly begun to understand, much less emulate.

The term “bird’s nest” has come to describe a messy hairdo, tangled fishing line and other unspeakably knotty conundrums. But that does birds an injustice. Their tiny brains, dense with neurons, produce marvels that have long captured scientific interest as naturally selected engineering solutions — yet nests are still not well understood.

One effort to disentangle the structural dynamics of the nest is underway in the sunny yellow lab — the Mechanical Biomimetics and Open Design Lab — of Hunter King, an experimental soft-matter physicist at the University of Akron in Ohio.

“We hypothesize that a bird nest might effectively be a disordered stick bomb, with just enough stored energy to keep it rigid,” Dr. King said. He is the principal investigator of an ongoing study, with a preliminary review paper, “Mechanics of randomly packed filaments — The ‘bird nest’ as meta-material,” recently published in the Journal of Applied Physics.

From a simple blood draw, microbial DNA may reveal who has cancer and which type, even at early stages.

When Gregory Poore was a freshman in college, his otherwise healthy grandmother was shocked to learn that she had late-stage pancreatic cancer. The condition was diagnosed in late December and she died in January.

"She had virtually no warning signs or symptoms," Poore said. "No one could say why her cancer wasn't detected earlier or why it was resistant to the treatment they tried."

As Poore came to learn through his college studies, cancer has traditionally been considered a disease of the human genome -- mutations in our genes allow cells to avoid death, proliferate and form tumors. But when Poore saw a 2017 study in Science that showed how microbes invaded a majority of pancreatic cancers and were able to break down the main chemotherapy drug given to these patients, he was intrigued by the idea that bacteria and viruses might play a bigger role in cancer than anyone had previously considered.

Poore is currently an MD/PhD student at University of California San Diego School of Medicine, where he's conducting his graduate thesis work in the lab of Rob Knight, PhD, professor and director of the Center for Microbiome Innovation. Together with an interdisciplinary group of collaborators, Poore and Knight have developed a novel method to identify who has cancer, and often which type, by simply analyzing patterns of microbial DNA -- bacterial and viral -- present in their blood.

The study, published March 11, 2020 in Nature, may change how cancer is viewed, and diagnosed.

Despite being the closest planet to the Sun, Mercury is home to a surprising amount of ice. Now, researchers at Georgia Tech have put forward an explanation for how at least some of it got there – and it turns out, the heat plays an important role.

Most of Mercury is a broiling hot hell, where daytime temperatures peak at a toasty 427 °C (800 °F). But with no atmosphere to spread the heat around, the poles remain chilly, and the floors of some deep craters never see sunlight. There, temperatures can be as low as -170 °C (-274 °F) – the perfect conditions for ice to form.

And form it does, with spacecraft observations and other calculations showing large deposits at both poles of the planet. How it actually got there in the first place has remained a mystery, but now the Georgia Tech team has proposed at least a partial explanation.

The team says that protons – charged particles from the Sun – pelt the surface of Mercury, creating minerals called hydroxyl groups (OH) in the soil. Then, the intense heat helps release and energize these minerals, so they collide and form water molecules and hydrogen.

These water molecules then drift around the planet. Some will inevitably be broken down again by the extreme sunlight, but some molecules will settle in the polar craters, where the cold conditions are ready to make some ice.

“The total amount that we postulate that would become ice is 10 trillion kg (11 billion tons) over a period of about 3 million years,” says Brant Jones, first author of the study. “The process could easily account for up to 10 percent of Mercury’s total ice.” The rest, they ponder, would arrive through asteroid strikes. That doesn’t necessarily mean the asteroid itself has to be carrying much water – the forces of the impact itself can trigger a chemical reaction that produces the stuff.

The ozone layer above Antarctica has recovered so much, it's actually stopped many worrying changes in the Southern Hemisphere's atmosphere. If you're looking for someone to thank, try the world at large.

A new study suggests the Montreal Protocol - the 1987 agreement to stop producing ozone depleting substances (ODSs) - could be responsible for pausing, or even reversing, some troubling changes in air currents around the Southern Hemisphere.

Swirling towards our planet's poles at a high altitude are fast air currents known as jet streams. Before the turn of the century, ozone depletion had been driving the southern jet stream further south than usual. This ended up changing rainfall patterns, and potentially ocean currents as well.

Then, a decade or so after the protocol was signed, that migration suddenly stopped. Was it a coincidence? Using a range of models and computer simulations, researchers have now shown this pause in movement was not driven by natural shifts in winds alone. Instead, only changes in the ozone could explain why the creep of the jet stream had suddenly stopped.

In other words, the impact of the Montreal Protocol appears to have paused, or even slightly reversed, the southern migration of the jet stream. And for once, that's actually good news.

In Australia, for instance, changes to the jet stream have increased the risk of drought by pushing rain away from coastal areas. If the trend does reverse, those rains might return.

"The 'weather bands' that bring our cold fronts have been narrowing towards the south pole, and that's why southern Australia has experienced decreasing rainfall over the last thirty years or so," says Ian Rae, organic chemist from the University of Melbourne who was not involved in the study." If the ozone layer is recovering, and the circulation is moving north, that's good news on two fronts (pun not intended)."

Still, we may not be celebrating for long. While improvements in cutting back our reliance on ODSs have certainly allowed the ozone to recover somewhat, carbon dioxide levels continue to creep upwards and place all that progress at risk. Last year, the Antarctic ozone hole hit its smallest annual peak on record since 1982, but the problem isn't solved, and this record may have something to do with unusually mild temperatures in that layer of the atmosphere.

What's more, in recent years, there's been a surge in ozone-depleting chemicals, coming from industrial regions in China. "We term this a 'pause' because the poleward circulation trends might resume, stay flat, or reverse," says atmospheric chemist Antara Banerjee from the University of Colorado Boulder. "It's the tug of war between the opposing effects of ozone recovery and rising greenhouse gases that will determine future trends."

The Montreal Protocol is proof that if we take global and immediate action we can help pause or even reverse some of the damage we've started. Yet even now, the steady rise in greenhouse gas emissions is a reminder that one such action is simply not enough.

The study was published in Nature.

Among the top coronavirus news out today are: U.S. is the new epicenter of the virus, a cat tests positive for the coronavirus and global COVID-19 cases have reached around 680,000. See below for more. For other info: U.S. case counts, coronavirus symptoms, our kids guide, comparison with seasonal flu and treatments in the works, corona virus forums, trends and podcasts.

Reducing methane emissions from human activities will have a greater impact on curbing future global warming than scientists previously thought.

Methane is a powerful greenhouse gas and large contributor to global warming. Methane emissions to the atmosphere have increased by approximately 150 percent over the past three centuries, but it has been difficult for researchers to determine exactly where these emissions originate; heat-trapping gases like methane can be emitted naturally, as well as from human activity.

University of Rochester researchers Benjamin Hmiel, a postdoctoral associate in the lab of Vasilii Petrenko, a professor of earth and environmental sciences, and their collaborators, measured methane levels in ancient air samples and found that scientists have been vastly underestimating the amount of methane humans are emitting into the atmosphere via fossil fuels. In a paper published in Nature, the researchers indicate that reducing fossil fuel use is a key target in curbing climate change.

"Placing stricter methane emission regulations on the fossil fuel industry will have the potential to reduce future global warming to a larger extent than previously thought," Hmiel says.

The surge in New York City's coronavirus infections is already so critical that the chief medical officer at a major hospital system warned staff of the grim reality: "...there will be loss, and suffering, and at times perhaps each of us will question our will to fight."

The coronavirus — which is hospitalizing severely sick young and old people alike — has already had a punishing, paramount influence on human civilization, and it will get much worse. But today's wide-scale shutdown of cities, extreme social distancing measures, and plummeting transportation usage will have no immediate, meaningful impact on Earth's colossal carbon dioxide woes or the planet's relentless warming trend.

The rising atmospheric concentrations of the potent heat-trapping gas carbon dioxide — now at its highest levels in at least 800,000 years, but more likely millions of years — hasn't slowed much, if at all. And an event that will cost countless lives wasn't ever a climate fix, anyhow.

"This is not anyone’s idea of a solution to the climate crisis," said Kristopher Karnauskas, a climate scientist at the University of Colorado Boulder. Slowing down the rise in CO2 will mean big, long-term societal changes. If widespread economic shutdowns persist through the coming months, we'll likely see a slowing down of rising CO2 numbers in the atmosphere. But, critically, this won't make a dent in the mass, or pile, of carbon dioxide we've built up over the last 150 years. 

"The pile is still there," said Ralph Keeling, the director of the Scripps CO2 Program at the Scripps Institution of Oceanography. "We're not getting rid of the pile, but time is running out".

Three decades after Voyager 2’s flyby of Uranus, scientists took another look at the data. This time, they noticed a tiny squiggle that could mean giant globs of Uranus’ atmosphere are escaping to space. The planet is shedding its atmosphere into the void, a signal that was recorded but overlooked in 1986 when the robotic spacecraft flew past.

Nanostructured layers boast countless potential properties -- but how can the most suitable one be identified without any long-term experiments? A team has ventured a shortcut: using a machine learning algorithm, the researchers were able to reliably predict the properties of such a layer.

Scientists at the University of Sussex have measured a property of the neutron – a fundamental particle in the universe - more precisely than ever before. Their research is part of an investigation into why there is matter left over in the universe, that is, why all the antimatter created in the Big Bang didn’t just cancel out the matter.

The team – which included the Science and Technology Facilities Council’s (STFC) Rutherford Appleton Laboratory in the UK, the Paul Scherrer Institute (PSI) in Switzerland, and a number of other institutions – was looking into whether or not the neutron acts like an “electric compass”.  Neutrons are believed to be slightly asymmetrical in shape, being slightly positive at one end and slightly negative at the other - a bit like the electrical equivalent of a bar magnet. This is the so-called “electric dipole moment” (EDM), and is what the team was looking for.

This is an important piece of the puzzle in the mystery of why matter remains in the Universe, because scientific theories about why there is matter left over also predict that neutrons have the "electric compass” property, to a greater or lesser extent. Measuring it then it helps scientists to get closer to the truth about why matter remains.

The team of physicists found that the neutron has a significantly smaller EDM than predicted by various theories about why matter remains in the universe; this makes these theories less likely to be correct, so they have to be altered, or new theories found.  In fact it’s been said in the literature that over the years, these EDM measurements, considered as a set, have probably disproved more theories than any other experiment in the history of physics.  The results are reported today, Friday 28 February 2020, in the journal Physical Review Letters. 

Professor Philip Harris, Head of the School of Mathematical and Physical Sciences and leader of the EDM group at the University of Sussex, said: “After more than two decades of work by researchers at the University of Sussex and elsewhere, a final result has emerged from an experiment designed to address one of the most profound problems in cosmology for the last fifty years: namely, the question of why the Universe contains so much more matter than antimatter, and, indeed, why it now contains any matter at all.  Why didn’t the antimatter cancel out all the matter? Why is there any matter left"?

“The answer relates to a structural asymmetry that should appear in fundamental particles like neutrons. This is what we’ve been looking for.  We’ve found that the “electric dipole moment” is smaller than previously believed. This helps us to rule out theories about why there is matter left over - because the theories governing the two things are linked. We have set a new international standard for the sensitivity of this experiment. What we’re searching for in the neutron - the asymmetry which shows that it is positive at one end and negative at the other – is incredibly tiny. Our experiment was able to measure this in such detail that if the asymmetry could be scaled up to the size of a football, then a football scaled up by the same amount would fill the visible Universe". 

Brain imprints on cranial bones from great apes and humans refute the long-held notion that the human pattern of brain asymmetry is unique.

The left and right side of the brain are involved in different tasks. This functional lateralization and associated brain asymmetry are well documented in humans, but little is known about brain asymmetry in our closest living relatives, the great apes. Using endocasts (imprints of the brain on cranial bones), scientists now challenge the long-held notion that the human pattern of brain asymmetry is unique. They found the same asymmetry pattern in chimpanzees, gorillas, and orangutans. However, humans were the most variable in this pattern. This suggests that lateralized, uniquely human cognitive abilities, such as language, evolved by adapting a presumably ancestral asymmetry pattern.

The left and right side of our brain are specialized for some cognitive abilities. For example, in humans, language is processed predominantly in the left hemisphere, and the right hand is controlled by the motor cortex in the left hemisphere. The functional lateralization is reflected by morphological asymmetry of the brain. Left and right hemisphere differ subtly in brain anatomy, the distribution of nerve cells, their connectivity and neurochemistry. Asymmetries of outer brain shape are even visible on endocasts. Most humans have a combination of a more projecting left occipital lobe (located in the back of the brain) with a more projecting right frontal lobe. Brain asymmetry is commonly interpreted as crucial for human brain function and cognition because it reflects functional lateralization. However, comparative studies among primates are rare and it is not known which aspects of brain asymmetry are really uniquely human. Based on previously available data, scientists assumed that many aspects of brain asymmetry evolved only recently, after the split between the human lineage from the lineage of our closest living relatives, the chimpanzees.

In a recent paper researchers from the Max Planck Institute for Evolutionary Anthropology and the University of Vienna measured the magnitude and pattern of shape asymmetry of endocasts from humans and apes. "Great ape brains are rarely available for study, but we have developed methods to extract brain asymmetry data from skulls, which are easier to access. This made our study possible in the first place," says lead author Simon Neubauer.

The team found that the magnitude of asymmetry was about the same in humans and most great apes. Only chimpanzees were, on average, less asymmetric than humans, gorillas, and orangutans. They also investigated the pattern of asymmetry and could demonstrate that not only humans, but also chimpanzees, gorillas, and orangutans showed the asymmetry pattern previously described as typically human: the left occipital lobe, the right frontal lobe, as well as the right temporal pole and the right cerebellar lobe projecting more relatively to their contralateral parts.

"What surprised us even more," says Philipp Mitteroecker, a co-author of the study, "was that humans were least consistent in this asymmetry with a lot of individual variation around the most common pattern." The authors interpret this as a sign of increased functional and developmental modularization of the human brain. For example, the differential projections of the occipital lobe and the cerebellum are less correlated in humans than in great apes. This finding is interesting because the cerebellum in humans underwent dramatic evolutionary changes and it seems that thereby its asymmetry was affected as well.

The finding of a shared asymmetry pattern but greater variability in humans is intriguing for the interpretation of human brain evolution. An endocast of one of our fossil ancestors that shows this asymmetry can no longer be interpreted as evidence for human-specific functional brain lateralization without other (archaeological) data. Philipp Gunz, a co-author of the study, explains: "This shared asymmetry pattern of the brain evolved already before the origin of the human lineage. Humans seem to have built upon this morphological pattern to establish functional brain lateralization related to typical human behaviors."

Mesa Biotech announced it has received Emergency Use Authorization (EUA) from the U.S. Food & Drug Administration (FDA) for its Accula™ SARS-CoV-2 Test, which gives COVID-19 diagnostic results in 30 minutes. Mesa Biotech Inc., a privately-held, molecular diagnostic company has developed an affordable, easy to use testing platform designed for point-of-care (POC) infectious disease diagnosis. The COVID-19 test uses this patented technology to enable 'near patient' testing allowing testing outside of the central laboratory.

"Mesa is excited to immediately begin shipping our rapid, molecular SARS-CoV-2 test so people can get answers in 30 minutes. Our Accula system is easy to use and fits in the palm of your hand. This allows many units to be run side by side in the doctor's office further increasing the speed of COVID-19 diagnosis.

Accula provides a true decentralized testing solution for COVID-19 at the point of care," said Hong Cai, Co-founder and Chief Executive Officer, Mesa Biotech, Inc. "Our test will provide a highly accessible means for healthcare professionals to access laboratory quality results close in their office to aid in the decision to isolate, treat or dismiss potential carriers of the virus. The potential to reduce the growing strain on our nation's hospitals is tremendous."

The Accula SARS-CoV-2 Test is a visually read test using polymerase chain reaction (PCR) technology to detect SARS-CoV-2 (the virus responsible for COVID-19) via throat and nasal swab samples. Similar to Mesa Biotech's commercially available tests for influenza and RSV, the Accula SARS-CoV-2 Test is designed for the point-of-care use, including temporary screening facilities, physician office labs, urgent care, and long term nursing facilities.

The system complements central laboratories where current testing is performed. Mesa Biotech's compact coronavirus test yields laboratory-quality results in approximately 30 minutes. Mesa Biotech's technology was developed at Los Alamos National Lab supported by NIH grants from the National Institute of Allergy and Infectious Diseases (NIAID) and the Western Regional Centers for Excellence in Biodefense and Emerging Infectious Disease program. Last week, the company received funding from the U.S. Health and Human Services for development of its SARS-CoV-2 test. Since its inception, the company has focused on technology well-suited for emergency defense and rapid deployment for SARS, Ebola and other emerging infectious diseases. Mesa Biotech's platform was specifically designed for use outside the lab to enable rapid responses to global pandemics, such as COVID-19.

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), in collaboration with researchers at McMaster University and University of Pittsburgh, have developed a new platform for all-optical computing, meaning computations done solely with beams of light.

"Most computation right now uses hard materials such as metal wires, semiconductors and photodiodes to couple electronics to light," said Amos Meeks, a graduate student at SEAS and co-first author of the research. "The idea behind all-optical computing is to remove those rigid components and control light with light.

Imagine, for example, an entirely soft, circuitry-free robot driven by light from the sun." These platforms rely on so-called non-linear materials that change their refractive index in response to the intensity of light. When light is shone through these materials, the refractive index in the path of the beam increases, generating its own, light-made waveguide. Currently, most non-linear materials require high-powered lasers or are permanently changed by the transmission of light.

Now, researchers developed a fundamentally new material that uses reversible swelling and contracting in a hydrogel under low laser power to change the refractive index. The hydrogel is composed of a polymer network that is swollen with water, like a sponge, and a small number of light-responsive molecules known as spiropyran (which is similar to the molecule used to tint transition lenses). When light is shone through the gel, the area under the light contracts a small amount, concentrating the polymer and changing the refractive index. When the light is turned off, the gel returns to its original state.

When multiple beams are shone through the material, they interact and affect each other, even at large distances. Beam A could inhibit Beam B, Beam B could inhibit Beam A, both could cancel each other out or both could go through -- creating an optical logic gate. "Though they are separated, the beams still see each other and change as a result," said Kalaichelvi Saravanamuttu, an associate professor of Chemistry and Chemical Biology at McMaster and co-senior author of the study. "We can imagine, in the long term, designing computing operations using this intelligent responsiveness."

"Not only can we design photoresponsive materials that reversibly switch their optical, chemical and physical properties in the presence of light, but we can use those changes to create channels of light, or self-trapped beams, that can guide and manipulate light," said co-author Derek Morim, a graduate student in Saravanamuttu's lab.

"Materials science is changing," said Joanna Aizenberg, the Amy Smith Berylson Professor of Materials Science at SEAS and co-senior author of the study. "Self-regulated, adaptive materials capable of optimizing their own properties in response to environment replace static, energy-inefficient, externally regulated analogs. Our reversibly responsive material that controls light at exceptionally small intensities is yet another demonstration of this promising technological revolution."