Warm Pasta Helps Hot, Angry Neutron Stars Cool Down (Astronomy)

Neutron stars are the angry ghosts of giant stars: hot, whirling cores of exotic matter left behind after supernovas. Like thermoses filled with hot noodle soup, it takes eons for them to cool down. But now, researchers think they know how these stars do it: with a giant helping of pasta.

Neutron stars are among the densest objects in the universe. (Image: © Shutterstock)

No, these ultradense stellar corpses aren’t filled with spaghetti. Instead, neutron stars cool down by releasing ethereal particles known as neutrinos. And the new study shows they accomplish that task thanks to an in-between type of matter known as nuclear pasta, a ripply, coiled material in which atoms almost, but don’t quite, mush together. This nuclear pasta structure creates low-density regions inside the stars, allowing neutrinos, and heat, a way out.

Trapped heat 

A teaspoon of matter scraped off a neutron star’s surface would weigh billions of tons, more than every human being on Earth combined. That density helps them trap heat extremely well. And while our sun, which is considered a yellow dwarf star, releases most of its heat in the form of light, light particles produced inside a neutron star rarely make it to the surface to escape. Still, these raging undead stars — each about the size of an American city — do eventually calm down, mostly by emitting neutrinos. 

To understand how they cool down, the researchers of a new study, published Oct. 6 in the journal Physical Review C, took a closer look at the matter inside neutron stars.

Ordinary stars are made up of conventional matter, or atoms: tiny balls of protons and neutrons surrounded by relatively huge whirling clouds of electrons. The interiors of neutron stars, meanwhile, are so dense that atomic structure breaks down, creating a vast ocean of so-called nuclear matter. Outside of neutron stars, nuclear matter refers to the stuff within atomic nuclei, dense balls of protons and neutrons. And it is governed by complex rules that scientists still don’t fully understand

Pasta is what lies between conventional matter and nuclear matter.

“Pasta is something intermediate between nuclear matter and conventional matter,” said study co-author Charles Horowitz, a physicist at Illinois State University “If you start squeezing matter really, really hard in a neutron star, the nuclei get closer and closer together and eventually they start to touch,” Horowitz told Live Science. “And when they start to touch, weird things happen.”

At some point, pressures rise high enough that conventional matter’s structure collapses entirely into undifferentiated nuclear broth. But just before that happens, there’s a region of pasta.

In the pasta zone, Coulomb repulsion (the force that pushes charged particles apart) and nuclear attraction (the force that binds protons and neutrons together at very short distances) start to act against one another. In regions where the nuclei touch but atomic structure hasn’t broken down entirely, matter contorts into complicated shapes, termed “pasta.” Scientists have words for the different varieties of this stuff: gnocchi, waffle, lasagna and anti-spaghetti.

“The shapes really do look like pasta shapes,” Horowitz said.

A computer-generated image shows stacked layers of nuclear pasta. (Image credit: Z. Lin et al. [)

Scientists have known for most of the last decade that this pasta lies inside neutron stars, just beneath their crusts in the region where conventional matter transitions into bizarre, poorly-understood nuclear stuff. And they also knew that neutrino emissions help cool neutron stars. The new study shows how the pasta helps free neutrinos.

Study lead author Zidu Lin, a postdoctoral researcher at the University of Arizona, designed a series of vast computer simulations that showed how neutrinos might emerge in this uncanny environment, Horowitz said.

The basic formula for producing a neutrino in a neutron star is straightforward: A neutron decays, transforming into a slightly-lighter, low-energy proton and an ultralight neutrino. It’s a simple process known to occur elsewhere in space, including in our sun. (Right this second, a vast stream of solar neutrinos is streaming through your body.)

But conditions have to be right for this recipe to work. And in a neutron star, conditions look wrong.

Neutron stars, as the name implies, have plenty of neutrons, all zipping around at high energies with lots of momentum. But the neutrino recipe requires producing a low-energy proton with almost no  momentum. Momentum can’t just disappear though. It’s always conserved. That’s Isaac Newton’s First Law of Motion. (It’s also why if your car stops suddenly and you’re not wearing a seatbelt you go flying out the window.)

Featherweight neutrinos can’t take on all the momentum of relatively bulky decaying neutrons. So the only other place for momentum to go is out into the surrounding environment.

Dense, rigid nuclear matter is a terrible place for dumping momentum though. It’s like driving a sports car at high speed into a thick slab of granite; the rock will hardly move and the car will pancake as that  momentum has nowhere else to go. Simple models of neutron star emissions struggle to explain how nuclear matter could absorb enough momentum for neutrinos to escape.

Lin’s model showed that nuclear pasta solves much of this problem. Those coiled, layered shapes have low-density regions. And the pasta can compress, absorbing momentum in a rippling motion. It’s as if that granite wall were mounted on a spring that compressed upon the car’s impact.

The researchers showed that neutrino emissions from nuclear pasta are likely vastly more efficient than neutrino emissions at a neutron star’s core. That means pasta is likely responsible for much of the cooling.

This research, Horowitz said, does suggest that neutron stars cool more slowly than expected. That means they live longer. Histories of space-time will have to be tweaked, he said, to account for their uncanny persistence at extreme heat across eons.

Originally published on Live Science.

Why Are Galaxies Different Shapes? (Astronomy)

Look into the night sky and you’ll glimpse the stars from hundreds of billions of galaxies. Some galaxies are swirling blue disks like our own Milky Way, others are red spheres or misshapen, clumpy messes or something in between. Why the different configurations? It turns out that a galaxy’s shape tells us something about the events in that galaxy’s ultra-long life.

An artist’s impression of the Wolfe Disk, a massive disk galaxy in the early universe.
(Image: © NRAO/AUI/NSF, S. Dagnello)

At the very basic level there are two classifications for galaxy shapes: disk and elliptical. A disk galaxy, also called a spiral galaxy, is shaped like a fried egg, said Cameron Hummels, theoretical astrophysicist at Caltech. These galaxies have a more spherical center, like the yolk, surrounded by a disk of gas and stars — the egg white. The Milky Way and our nearest galaxy neighbor Andromeda fall into this category.

In theory, disk galaxies initially form from clouds of hydrogen. Gravity draws the gas particles together. As the hydrogen atoms draw closer, the cloud begins to rotate and their collective mass increases, which causes their gravitational force to also go up. Eventually, the gravity causes the gas to collapse into a swirling disk. Most of the gas is in the rim, where it feeds star formation. Edwin Hubble, who confirmed the existence of galaxies beyond our own only a century ago, called disk galaxies late-type galaxies because he suspected their shape meant they formed later in the history of the universe, according to NASA

Alternatively, elliptical galaxies — what Hubble called early-type galaxies — appear to be older. Instead of rotating, like disk galaxies, stars in elliptical galaxies have more random movement, according to Robert Bassett, an observational astrophysicist who studies galaxy evolution at Swinburne University in Melbourne, Australia. Elliptical galaxies are thought to be a product of a galaxy merger. When two galaxies of equal mass merge, their stars start to tug on one another with gravity, disrupting the stars’ rotation and creating a more random orbit, Bassett said. 

Not every merger results in an elliptical galaxy. The Milky Way is actually quite old and large, but maintains its disk shape. It’s been adding to its mass by simply drawing in dwarf galaxies, which are much smaller than our home galaxy, and collecting free gas from the universe. However, Andromeda, our disk-shaped sister galaxy, is actually headed straight for the Milky Way, Bassett told Live Science. So billions of years from now, the two spiraling galaxies could merge and each of the duo’s starry disks will offset the other’s rotation, creating a more random elliptical galaxy. 

These mergers are far from instantaneous. They take hundreds of millions, even billions of years. In fact, there are ongoing mergers that are moving so slowly — from our perspective — that they appear static. “They’ve basically been in the exact same state, unchanged for all of human civilization,” Bassett said. Hubble gave these galaxies their own classification — irregular galaxies. To look at them, “they are usually a mess with multiple components,” Hummels said. “Irregular galaxies just look like a big train wreck,” Bassett added.

This galaxy, known as Mrk 820, is classified as a lenticular galaxy. Surrounding Mrk 820 is a slew of other galaxy types from elliptical to spiral. (Image credit: ESA/Hubble & NASA and N. Grogin (STScI), Acknowledgement: Judy Schmidt)

Finally, a less common shape, lenticular galaxies seem to be a mix between an elliptical and a disk galaxy. It may be, Bassett said, that when a disk galaxy uses up all its gas and can’t form any new stars the existing stars begin to interact. Their gravitational tug on one another creates a shape that looks like a lentil — kind of elliptical but still a rotating disk.

What scientists have uncovered so far about galaxies and their 3D shapes has been inferred using thousands of 2D images and by relying on other properties, such as galaxy color and motion, to fill in the blanks, Bassett said. 

For example, the younger age of disk galaxies is corroborated by their blue color. Blue stars are generally larger, and they burn faster and hotter (blue light has a higher frequency and is thus more energetic than red light). Meanwhile, elliptical galaxies are filled with older stars — called red dwarfs — that aren’t burning quite as hot or fast.

Still, despite all we have learned about the massive celestial structures around us, there’s still so much we don’t know, Hummels said.

“Galaxy formation and evolution is one of the biggest open questions in the field of astronomy and astrophysics,” Hummels said. 

Originally published on Live Science.

Black Holes Could Become Massive Particle Accelerators (Astronomy)

Black holes are powerful engines of pure gravity, capable of pulling on objects so intensely that they can’t possibly escape. 

When those objects near the event horizon, they’re accelerated to incredible velocities. Now, some physicists are suggesting harnessing the gravitational pull of black holes to create ferocious particle accelerators. The trick, the new study finds, is to carefully set everything up so that particles don’t get lost forever in the insatiable black hole. This new insight may help us identify black holes from the streams of particles blasting away from them.

Falling together

Let’s say a particle starts falling into a black hole. As it gets closer to the black hole, it speeds up, just like a ball speeds up as it rolls down a hill. In fact, it’s much worse than a ball rolling down a hill, because the gravity of a black hole is so strong that particles can fall in faster than the speed of light

The event horizon — the distance from the black hole where infalling particles reach the speed of light — defines the boundary of the black hole.

If a particle falls in, it is lost forever, locked behind the event horizon with no hope of escape. When thinking about making a particle accelerator, that region is a no-go, as an accelerator that never spits out particles wouldn’t be any fun.

But that’s the story of just one lonely particle. When two or more particles are involved, things can get interesting.

Going to the extreme

If two particles approach a black hole, they each receive a huge boost in energy. Our current particle colliders accelerate heavy particles to over 99% of the speed of light, but it takes a lot of work (and in the case of the world’s largest atom smasher, the Large Hadron Collider, a ring of superconducting channels nearly 17 miles, or 27 kilometers, long). Black holes create this kind of insane acceleration simply by existing.

As the two particles approach the event horizon, their speeds ratchet up. And if they just so happen to have the right combination of incoming speed and direction, they can ricochet off each other, sending one of them plummeting to its doom, as the other skirts the edge of the event horizon before flying off to safety.

These events are rare, but previous research has found that the particles are capable of smashing together with arbitrarily high energies — it all depends on how close they can get to the event horizon (and how close they get to the speed of light) at the moment of collision.

This rimshot particle accelerator would work even better for rotating black holes. Due to their extreme spin, these types of black holes can rotate space-time around the event horizon, allowing more particles to reach the vicinity of the event horizon before flying off to infinity.

©trumpwallpapers.

There is one catch to this story, however. Due to the complex nature of the mathematics involved, this black-hole-as-particle-cannon scenario has only been explored in the case of what’s known as “extremal” black holes. These are theoretical black holes that are the smallest possible mass that can rotate at a given speed. In real life, scientists think that almost all (if not absolutely all) black holes are much more massive than they strictly need to be.

This would make real-life black holes “non-extremal,” which means that until now, physicists weren’t sure if they could act as particle colliders or not.

It turns out, they do, thanks to new research published on Oct. 1 in the preprint database arXiv and set to publish in the journal Physics Review D. The new research found that more realistic black holes — including massive, rotating black holes and electrically charged black holes can still accelerate particles usefully.

It’s not a generic particle gun, however. In order to get the high-speed kick required, the incoming particles have to be rushing in at already high speeds, which kind of negates the point. But the researchers found that multiple, low-speed collisions can take place near the event horizon, leading to the desired high-energy output.

Unfortunately, since the collisions have to occur near the event horizon in order to reach such insane energies, when they escape the black hole they have to fight against all that almost-overwhelming gravity, slowing them down before they reach true freedom in interstellar space. Thankfully, the researchers found a solution for that problem too, showing that high-energy collisions can occur around rotating black holes without getting too close to the event horizons — meaning that particles can shoot off in a blaze of glory.

Originally published on Live Science.

What Happens At The Center Of A Black Hole? (Astronomy)

The singularity at the center of a black hole is the ultimate no man’s land: a place where matter is compressed down to an infinitely tiny point, and all conceptions of time and space completely break down. And it doesn’t really exist. Something has to replace the singularity, but we’re not exactly sure what. 

Let’s explore some possibilities.

Planck stars

It could be that deep inside a black hole, matter doesn’t get squished down to an infinitely tiny point. Instead, there could be a smallest possible configuration of matter, the tiniest possible pocket of volume.

This is called a Planck star, and it’s a theoretical possibility envisioned by loop quantum gravity, which is itself a highly hypothetical proposal for creating a quantum version of gravity. In the world of loop quantum gravity, space and time are quantized — the universe around us is composed of tiny discrete chunks, but at such an incredibly tiny scale that our movements appear smooth and continuous.

This theoretical chunkiness of space-time provides two benefits. One, it takes the dream of quantum mechanics to its ultimate conclusion, explaining gravity in a natural way. And two, it makes it impossible for singularities to form inside black holes.

As matter squishes down under the immense gravitational weight of a collapsing star, it meets resistance. The discreteness of space-time prevents matter from reaching anything smaller than the Planck length (around 1.68 times 10^-35 meters, so…small). All the material that has ever fallen into the black hole gets compressed into a ball not much bigger than this. Perfectly microscopic, but definitely not infinitely tiny.

This resistance to continued compression eventually forces the material to un-collapse (i.e., explode), making black holes only temporary objects. But because of the extreme time dilation effects around black holes, from our perspective in the outside universe it takes billions, even trillions, of years before they go boom. So we’re all set for now.

Gravastars

Another attempt to eradicate the singularity — one that doesn’t rely on untested theories of quantum gravity — is known as the gravastar. It’s such a theoretical concept that my spell checker didn’t even recognize the word. 

The difference between a black hole and a gravastar is that instead of a singularity, the gravastar is filled with dark energy. Dark energy is a substance that permeates space-time, causing it to expand outward. It sounds like sci-fi, but it’s real: dark energy is currently in operation in the larger cosmos, causing our entire universe to accelerate in its expansion.

As matter falls onto a gravastar, it isn’t able to actually penetrate the event horizon (due to all that dark energy on the inside) and therefore just hangs out on the surface. But outside that surface, gravastars look and act like normal black holes.

However, recent observations of merging black holes with gravitational wave detectors have potentially ruled out the existence of gravastars, because merging gravastars will give a different signal than merging black holes, and outfits like LIGO (the Laser Interferometer Gravitational-Wave Observatory) and Virgo are getting more and more examples by the day. While gravastars aren’t exactly a no-go in our universe, they are definitely on thin ice.

Let’s go for a spin

Planck stars and gravastars may have awesome names, but the reality of their existence is in doubt. So maybe there’s a more mundane explanation for singularities, one that’s based on a more nuanced — and realistic — view of black holes in our universe.

The idea of a single point of infinite density comes from our conception of stationary, non-rotating, uncharged, rather boring black holes. Real black holes are much more interesting characters, especially when they spin.

The spin of a rotating black hole stretches the singularity into a ring. And according to the math of Einstein’s theory of general relativity (which is the only math we’ve got), once you pass through the ring singularity, you enter a wormhole and pop out through a white hole (the polar opposite of a black hole, where nothing can enter and matter rushes out at the speed of light) into an entirely new and exciting patch of the universe.

One challenge: the interiors of rotating black holes are catastrophically unstable. And this is according to the very same math that leads to the prediction of the traveling-to-a-new-universe stuff.

The problem with rotating black holes is that … well, they rotate. The singularity, stretched into a ring, is rotating at such a fantastic pace that it has incredible centrifugal force. And in general relativity, strong enough centrifugal forces act like antigravity: they push, not pull.

This creates a boundary inside the black hole, called the inner horizon. Outside this region, radiation is falling inward towards the singularity, compelled by the extreme gravitational pull. But radiation is pushed by the antigravity near the ring singularity, and the turning point is the inner horizon. If you were to encounter the inner horizon, you would face a wall of infinitely energetic radiation — the entire past history of the universe, blasted into your face in less than a blink of an eye.

The formation of an inner horizon sows the seeds for the destruction of the black hole. But rotating black holes certainly exist in our universe, so that tells us that our math is wrong and something funky is going on.

What’s really happening inside a black hole? We don’t know — and the scary part is that we may never know.

This article is republished here from space under common creative licenses

A New Spin On Atoms Gives Scientists A Closer Look At Quantum Weirdness (Quantum)

When atoms get extremely close, they develop intriguing interactions that could be harnessed to create new generations of computing and other technologies. These interactions in the realm of quantum physics have proven difficult to study experimentally due the basic limitations of optical microscopes.

Artist’s rendering of a method of measuring and controlling quantum spins developed at Princeton University. ©Rachel Davidowitz.

Now a team of Princeton researchers, led by Jeff Thompson, an assistant professor of electrical engineering, has developed a new way to control and measure atoms that are so close together no optical lens can distinguish them.

Described in an article published Oct. 30 in the journal Science, their method excites closely-spaced erbium atoms in a crystal using a finely tuned laser in a nanometer-scale optical circuit. The researchers take advantage of the fact that each atom responds to slightly different frequencies, or colors, of laser light, allowing the researchers to resolve and control multiple atoms, without relying on their spatial information.

In a conventional microscope, the space between two atoms effectively disappears when their separation is below a key distance called the diffraction limit, which is roughly equal to the light’s wavelength. This is analogous to two distant stars that appear as a single point of light in the night sky. However, this is also the scale at which atoms start to interact and give rise to rich and interesting quantum mechanical behavior.

“We always wonder, at the most fundamental level — inside solids, inside crystals — what do atoms actually do? How do they interact?” said physicist Andrei Faraon, a professor at the California Institute of Technology who was not involved in the research. “This [paper] opens the window to study atoms that are in very, very close proximity.”

Studying atoms and their interactions at tiny distances allows scientists to explore and control a quantum property known as spin. As a form of momentum, spin is usually described as being either up or down (or both, but that’s another story). When the distance between two atoms grows vanishingly small — mere billionths of a meter — the spin of one exerts influence over the spin of the other, and vice versa. As spins interact in this realm, they can become entangled, a term scientists use to describe two or more particles that are inextricably linked. Entangled particles behave as if they share one existence, no matter how far apart they later become. Entanglement is the essential phenomenon that separates quantum mechanics from the classical world, and it’s at the center of the vision for quantum technologies. The new Princeton device is a stepping stone for scientists to study these spin interactions with unprecedented clarity.

One important feature of the new Princeton device is its potential to address hundreds of atoms at a time, providing a rich quantum laboratory in which to gather empirical data. It’s a boon for physicists who hope to unlock reality’s deepest mysteries, including the spooky nature of entanglement.

Such inquiry is not merely esoteric. Over the past three decades, engineers have sought to use quantum phenomena to create complex technologies for information processing and communication, from the logical building blocks of emerging quantum computers, capable of solving otherwise impossible problems, to ultrasecure communication methods that can link machines into an unhackable quantum Internet. To develop these systems further, scientists will need to entangle particles reliably and exploit their entanglement to encode and process information.

Thompson’s team saw an opportunity in erbium. Traditionally used in lasers and magnets, erbium was not widely explored for use in quantum systems because it is difficult to observe, according to the researchers. The team made a breakthrough in 2018, developing a way to enhance the light emitted by these atoms, and to detect that signal extremely efficiently. Now they’ve shown they can do it all en masse.

When the laser illuminates the atoms, it excites them just enough for them to emit a faint light at a unique frequency, but delicately enough to preserve and read out the atoms’ spins. These frequencies change ever so subtly according to the atoms’ different states, so that “up” has one frequency and “down” has another, and each individual atom has its own pair of frequencies.

“If you have an ensemble of these qubits, they all emit light at very slightly different frequencies. And so by tuning the laser carefully to the frequency of one or the frequency of the other, we can address them, even though we have no ability to spatially resolve them,” Thompson said. “Each atom sees all of the light, but they only listen to the frequency they’re tuned to.”

The light’s frequency is then a perfect proxy for the spin. Switching the spins up and down gives researchers a way to make calculations. It’s akin to transistors that are either on or off in a classical computer, giving rise to the zeroes and ones of our digital world.

To form the basis of a useful quantum processor, these qubits will need to go a step further.

“The strength of the interaction is related to the distance between the two spins,” said Songtao Chen, a postdoctoral researcher in Thompson’s lab and one of the paper’s two lead authors. “We want to make them close so we can have this mutual interaction, and use this interaction to create a quantum logic gate.”

A quantum logic gate requires two or more entangled qubits, making it capable of performing uniquely quantum operations, such as computing the folding patterns of proteins or routing information on the quantum internet.

Thompson, who holds a leadership position at the U.S. Department of Energy’s new $115M quantum science initiative, is on a mission to bring these qubits to heel. Within the materials thrust of the Co-Design Center for Quantum Advantage, he leads the sub- qubits for computing and networking.

His erbium system, a new kind of qubit that is especially useful in networking applications, can operate using the existing telecommunications infrastructure, sending signals in the form of encoded light over silicon devices and optical fibers. These two properties give erbium an industrial edge over today’s most advanced solid-state qubits, which transmit information through visible light wavelengths that don’t work well with optical-fiber communication networks.

Still, to operate at scale, the erbium system will need to be further engineered.

While the team can control and measure the spin state of its qubits no matter how close they get, and use optical structures to produce high-fidelity measurement, they can’t yet arrange the qubits as needed to form two-qubit gates. To do that, engineers will need to find a different material to host the erbium atoms. The study was designed with this future improvement in mind.

“One of the major advantages of the way we have done this experiment is that it has nothing to do with what host the erbium sits in,” said Mouktik Raha, a sixth-year graduate student in electrical engineering and one of the paper’s two lead authors. “As long as you can put erbium inside it and it doesn’t jitter around, you’re good to go.”

References: Songtao Chen, Mouktik Raha, Christopher M. Phenicie, Salim Ourari, Jeff D. Thompson, “Parallel single-shot measurement and coherent control of solid-state spins below the diffraction limit”, Science 30 Oct 2020: Vol. 370, Issue 6516, pp. 592-595 DOI: 10.1126/science.abc7821 link: https://science.sciencemag.org/content/370/6516/592/tab-article-info

Provided by Princeton University, English School

Wistar Creates A New Synthetic DNA Vaccine Against Powassan Virus (Medcine)

Vaccine protects animals against tick-borne Powassan virus, an emerging infectious disease.

Scientists at The Wistar Institute have designed and tested the first-of-its-kind synthetic DNA vaccine against Powassan virus (POWV), targeting portions of the virus envelope protein. A rapidly reemerging tick-borne disease, POWV has been reported to be fatal in 10% of infected people with detrimental neurological consequences including encephalitis and meningitis. This new POWV vaccine candidate, described in a paper published today in PLOS Neglected Infectious Diseases, is one of many emerging infectious disease DNA vaccine discoveries being advanced by the Vaccine and Immunotherapy Center at The Wistar Institute.

Powassan virus is a tick-borne, emerging infectious disease. ©The Wistar Institute.

Unlike the widely recognized Lyme disease, POWV causes a little known, potentially deadly infectious disease that is transmitted through tick bites during fall and spring seasons. POWV is an RNA virus belonging to the flavivirus family, the same as Zika virus, but passed to people by ticks instead of mosquitoes.

Transmission can occur rapidly and symptoms including flu-like fever, body aches, skin rash, and headaches can present anytime during the 1-4 week incubation period. Although still considered relatively rare, in recent years the number of reported cases of people sick from Powassan virus has been increasing in North America, including infecting former U.S. Senator Kay Hagan who contracted Powassan virus and died from the disease. There are no vaccines or therapies available to treat or prevent this emerging infection.

Kar Muthumani, Ph.D., former associate professor and director of the Laboratory of Emerging Infectious Diseases at The Wistar Institute,* and senior author on the study, collaborated with the laboratory of David B. Weiner, Ph.D., executive vice president and director of Wistar’s Vaccine and Immunotherapy Center, to design and test this synthetic DNA vaccine.

The effectiveness of this vaccine was evaluated in preclinical studies that showed a single immunization elicited broad T and B cell immune responses in mice similar to those induced naturally in POWV-infected individuals, and that vaccine-induced immunity provided protection in a POWV challenge animal model.

“The significant protection in mice demonstrated by our vaccine is highly encouraging and strongly supports the importance of this vaccine approach for further study,” said Muthumani.

Residents of and visitors in POWV-endemic areas are considered at risk of infection, especially during outdoor work and recreational activities. In the U.S., cases of POWV disease have been reported in Northeastern states and the Great Lakes region.

“Given the risk of serious complications from POWV and the 300% increase in incidence of POWV infection over the past 16 years, we will continue efforts to advance this urgently needed emerging infectious disease vaccine candidate towards the clinic,” said Weiner.

References: Choi H, Kudchodkar SB, Ho M, Reuschel EL, Reynolds E, Xu Z, et al. (2020) A novel synthetic DNA vaccine elicits protective immune responses against Powassan virus. PLoS Negl Trop Dis 14(10): e0008788. doi:10.1371/journal.pntd.0008788 link: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0008788

Provided by Wistar Institute

New Cause Of Inflammation In People With HIV Identified (Medicine)

While current antiretroviral treatments for HIV are highly effective, data has shown that people living with HIV appear to experience accelerated aging and have shorter lifespans – by up to five to 10 years – compared to people without HIV. These outcomes have been associated with chronic inflammation, which could lead to the earlier onset of age-associated diseases, such as atherosclerosis, cancers, or neurocognitive decline. A new study led by researchers at Boston Medical Center examined what factors could be contributing to this inflammation, and they identified the inability to control HIV RNA production from existing HIV DNA as a potential key driver of inflammation. Published in The Journal of Infectious Diseases, the results underscore the need to develop new treatments targeting the persistent inflammation in people living with HIV in order to improve outcomes.

©gettyimages.

After infection, HIV becomes a part of an infected person’s DNA forever, and in most cases, infected cells are silent and do not replicate the virus. Occasionally, however, RNA is produced from this HIV DNA, which is a first step towards virus replication. Antiretroviral treatments help prevent HIV and AIDS-related complications, but they do not prevent the chronic inflammation that is common among people with HIV and is associated with mortality.

“Our study set out to identify a possible association between HIV latently infected cells with chronic inflammation in people with HIV who have suppressed viral loads,” said Nina Lin, MD, a physician scientist at Boston Medical Center (BMC) and Boston University School of Medicine (BUSM).

For this study, researchers had a cohort of 57 individuals with HIV who were treated with antiretroviral therapy. They compared inflammation in the blood and various virus measurements among younger (age less than 35 years) and older (age greater than 50 years) people living with HIV. They also compared the ability of the inflammation present in the blood to activate HIV production from the silent cells with the HIV genome. Their results suggest that an inability to control HIV RNA production even with antiretroviral drugs correlates with inflammation.

“Our findings suggest that novel treatments are needed to target the inflammation persistent in people living with HIV,” said Manish Sagar, MD, an infectious diseases physician and researcher at BMC and the study’s corresponding author. ‘Current antiretroviral drugs prevent new infection, but they do not prevent HIV RNA production, which our results point as a potential key factor driving inflammation in people living with HIV.”

According to the Centers for Disease Control and Prevention, it is estimated that 1.2 million Americans are living with HIV; however, approximately 14 percent of these individuals are not aware that they are infected. Another CDC reporter found that of those diagnosed and undiagnosed with HIV in 2018, 76 percent had received some form of HIV care; 58 percent were retained in care; and 65 percent had undetectable or suppressed HIV viral loads. Antiretroviral therapy prevents HIV progression and puts the risk of transmission almost to zero.

The authors note that these results need to be replicated in larger cohorts. “We hope that our study results will serve as a springboard for examining drugs that stop HIV RNA production as a way to reduce inflammation,” added Sagar, also an associate professor of medicine and microbiology at BUSM.

References: Alex Olson, Carolyn Coote, Jennifer E Snyder-Cappione, Nina Lin, Manish Sagar, HIV-1 transcription but not intact provirus levels are associated with systemic inflammation, The Journal of Infectious Diseases, , jiaa657, https://doi.org/10.1093/infdis/jiaa657 link: https://academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiaa657/5930820?guestAccessKey=433c214e-8fb1-459b-b935-51544a2dbb7c

Provided by Boston Medical Center

Researchers Devise New Method To Get The Lead Out (Engineering)

Commercially sold water filters do a good job of making sure any lead from residential water pipes does not make its way into water used for drinking or cooking.

Researchers in the lab of Daniel Giammar, the Walter E. Browne Professor of Environmental Engineering in the McKelvey School of Engineering, have devised a new method that allows them to extract lead from “point-of-use” filters, providing a clearer picture of what’s coming out of the faucet. ©Washington University in St. Louis.

Filters do not do a good job, however, of letting the user know how much lead was captured.

Until now, when a researcher, public works department or an individual wanted to know how much lead was in tap water, there wasn’t a great way to find out. Usually, a scientist would look at a one-liter sample taken from a faucet.

Researchers in the McKelvey School of Engineering at Washington University in St. Louis have devised a new method that allows them to extract the lead from these “point-of-use” filters, providing a clearer picture of what’s coming out of the faucet.

And they can do it in less than an hour.

Their research was published this past summer in the journal Environmental Science: Water Research & Technology.

The problem with just collecting a one-liter sample is that “We don’t know how long it was in contact with that lead pipe or if it just flowed through quickly. Everyone’s water use patterns are different,” said Daniel Giammar, the Walter E. Browne Professor of Environmental Engineering in the Department of Energy, Environmental & Chemical Engineering.

“Collecting a single liter is not a good way of assessing how much lead a resident would be exposed to if not using a filter,” he said. “To do that, you’d need to see all that the person was drinking or using for cooking.”

A better method would be to collect the lead from a filter that had been in use long enough to provide an accurate picture of household water use. Most of the commercial filters for sale at any major retail store will last for about 100 gallons — 40 times the amount of the typical water sample.

The idea to use filters in this way isn’t new, but it hasn’t been done very efficiently, precisely because the filters do such a good job at holding onto the lead.

Giammar said he had probably heard about this method previously, but a light went off after a conversation about indoor air quality. He had been talking to a professor at another institution who was monitoring indoor air quality using a box that sucked in air, collecting contaminants in a tube. The user can then remove the collection tube and send it to a lab to be analyzed.

“I said, ‘Let’s do what you’re doing with air,'” pull water through a filter, collect contaminants and then analyze them. “Then we realized, they already make and sell these filters.”

Liberating the lead

Point-of-use filters are typically made of a block of activated carbon that appears solid, almost like a lump of coal. The water filters through tiny pores in the carbon; the carbon binds to the lead, trapping it before the water flows out of the faucet.

“If you want to take the lead out of the water, you need something that is really good at strongly holding on to it,” which carbon is, Giammar said.

“So we had to hit it with something even stronger to pull that lead off.”

The solution? Acid.

Working with senior Elizabeth Johnson, graduate student Weiyi Pan tried different methods, but ultimately discovered that slowly passing an acidic solution through the filter would liberate 100% of the lead.

The entire process took about two liters of acid and about a half hour.

In the near future, Giammar sees the filters being put to use for research, as opposed to being put in the trash.

“The customer has a filter because they want to remove lead from the water. The water utility or researcher wants to know how much lead is in the home’s water over some average period of time,” Giammar said. Even if the customer doesn’t care, they’ve got this piece of data that usually they’d just throw away.

“We’d rather them send it to their utility service, or to us, and we can use it to get information.”

References: http://dx.doi.org/10.1039/d0ew00496k

Provided by Washington University in St. louis

A Malformation Illustrates The Incredible Plasticity Of The Brain (Neuroscience)

People born without a corpus callosum do not have a bridge between the two cerebral hemispheres. Neuroscientists from UNIGE have shown how the brain manages to adapt.

Neuronal fibers in a healthy brain (top) and a brain with agenesis of the corpus callosum (bottom). In the healthy brain, the two hemispheres are connected by the corpus callosum fibers, shown in red. These fibers are absent in the brain with corpus callosum agenesis. ©Unige/Siffredi.

One in 4,000 people is born without a corpus callosum, a brain structure consisting of neural fibres that are used to transfer information from one hemisphere to the other. A quarter of these individuals do not have any symptoms, while the remainder either have low intelligence quotients or suffer from severe cognitive disorders. In a study published in the journal Cerebral Cortex, neuroscientists from the University of Geneva (UNIGE) discovered that when the neuronal fibres that act as a bridge between the hemispheres are missing, the brain reorganises itself and creates an impressive number of connections inside each hemisphere. These create more intra-hemispheric connections than in a healthy brain, indicating that plasticity mechanisms are involved. It is thought that these mechanisms enable the brain to compensate for the losses by recreating connections to other brain regions using alternative neural pathways.

The corpus callosum develops in utero between the tenth and twentieth week of gestation. Agenesis of the corpus callosum is a congenital brain malformation in which this brain structure fails to develop, resulting in one out of 4,000 babies born without a corpus callosum. When it is missing, nothing replaces this structure measuring about ten centimetres, with the exception of cerebrospinal fluid. This means that the information transmitted from one hemisphere to the other can no longer be conveyed by the neuronal projections from the corpus callosum. «Their role in a healthy brain,» begins Vanessa Siffredi, a researcher in UNIGE’s Faculty of Medicine, «is to ensure the functioning of various cognitive and sensorimotor functions». Surprisingly, 25% of people with this malformation have no visible signs; 50% have average intelligence quotients and learning difficulties; and the remaining 25% suffer from severe cognitive disorders.

Mysterious fibres

The scientific literature shows that, in the absence of the corpus callosum, certain fibres designed to serve as a bridge between the hemispheres, known as Probst bundles, bypass the absent brain area and curl up inside each hemisphere. «The back-up zones vary from one individual to another. And we don’t understand their functions,» explains the neuroscientist. The UNIGE scientists – working in collaboration with their colleagues at the University of Melbourne – set out to understand this variability and to examine the role of the fibres. Using MRI brain imaging, they studied the anatomical and functional links between different brain regions of approximately 20 Australian children aged 8 to 17 suffering from agenesis of the corpus callosum.

A salutary role

This approach first made it possible to observe the physical relationships between the different regions of the brain, i.e. their structural links. In children with corpus callosum agenesis, the neural fibres inside each hemisphere are greater in number and of higher quality than in healthy brains. Furthermore, the UNIGE scientists succeeded in determining the correlations between the activity of different brain regions and their functional links. «If two regions are active together, it means they are communicating with each other,» explains Dr Siffredi. The data shows that intra and inter-hemispheric functional connectivity of brains without the corpus callosum are comparable to those of healthy brains. «Remarkably, communication between the two hemispheres is maintained. We think that plasticity mechanisms, such as the strengthening of structural bonds within each hemisphere, compensated for the lack of neuronal fibres between hemispheres. New connections are created and the signals can be re-routed so that communication is preserved between the two hemispheres.»

Predicting cognitive impairment

The Geneva neuroscientists likewise observed a correlation between the increase in intra-hemispheric connections and cognitive skills. This information is very interesting for clinical work since, as agenesis is currently detected by means of ultrasound during pregnancy, it is often proposed that a pregnancy be terminated. «In the not-too-distant future, we could imagine using MRI imaging to predict whether the malformation observed by ultrasound runs the risk of being associated with cognitive impairment or not, and so better inform future parents», concludes Dr Siffredi.

References: Vanessa Siffredi, Maria G Preti, Valeria Kebets, Silvia Obertino, Richard J Leventer, Alissandra McIlroy, Amanda G Wood, Vicki Anderson, Megan M Spencer-Smith, Dimitri Van De Ville, Structural Neuroplastic Responses Preserve Functional Connectivity and Neurobehavioural Outcomes in Children Born Without Corpus Callosum, Cerebral Cortex, , bhaa289, https://doi.org/10.1093/cercor/bhaa289 link: https://academic.oup.com/cercor/advance-article-abstract/doi/10.1093/cercor/bhaa289/5941685?redirectedFrom=fulltext

Provided by University Of Geneve