Amazing Science

On a quest to find the Universe’s largest black holes, Vanderbilt researcher identifies the center of the solar system within 100 meters.

In the search for previously undetected black holes that are billions of times more massive than the sun, Stephen Taylor, assistant professor of physics and astronomy and former astronomer at NASA's Jet Propulsion Laboratory (JPL) together with the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration has moved the field of research forward by finding the precise location -- the center of gravity of our solar system -- with which to measure the gravitational waves that signal the existence of these black holes. The potential presented by this advancement, co-authored by Taylor, was published in the journal the Astrophysical Journal in April 2020.

Black holes are regions of pure gravity formed from extremely warped spacetime. Finding the most titanic black holes in the Universe that lurk at the heart of galaxies will help us understand how such galaxies (including our own) have grown and evolved over the billions of years since their formation. These black holes are also unrivaled laboratories for testing fundamental assumptions about physics.

Gravitational waves are ripples in spacetime predicted by Einstein's general theory of relativity. When black holes orbit each other in pairs, they radiate gravitational waves that deform spacetime, stretching and squeezing space. Gravitational waves were first detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2015, opening new vistas on the most extreme objects in the universe. Whereas LIGO observes relatively short gravitational waves by looking for changes in the shape of a 4-km long detector, NANOGrav, a National Science Foundation (NSF) Physics Frontiers Center, looks for changes in the shape of our entire galaxy.

Taylor and his team are searching for changes to the arrival rate of regular flashes of radio waves from pulsars. These pulsars are rapidly spinning neutron stars, some going as fast as a kitchen blender. They also send out beams of radio waves, appearing like interstellar lighthouses when these beams sweep over Earth. Over 15 years of data have shown that these pulsars are extremely reliable in their pulse arrival rates, acting as outstanding galactic clocks. Any timing deviations that are correlated across lots of these pulsars could signal the influence of gravitational waves warping our galaxy.

"Using the pulsars we observe across the Milky Way galaxy, we are trying to be like a spider sitting in stillness in the middle of her web," explains Taylor. "How well we understand the solar system barycenter is critical as we attempt to sense even the smallest tingle to the web." The solar system barycenter, its center of gravity, is the location where the masses of all planets, moons, and asteroids balance out.

Where is the center of our web, the location of absolute stillness in our solar system? Not in the center of the sun as many might assume, rather it is closer to the surface of the star. This is due to Jupiter's mass and our imperfect knowledge of its orbit. It takes 12 years for Jupiter to orbit the sun, just shy of the 15 years that NANOGrav has been collecting data. JPL's Galileo probe (named for the famed scientist that used a telescope to observe the moons of Jupiter) studied Jupiter between 1995 and 2003, but experienced technical maladies that impacted the quality of the measurements taken during the mission.

A new analysis of white dwarf stars supports their role as a key source of carbon, an element crucial to all life, in the Milky Way and other galaxies.

Approximately 90 percent of all stars end their lives as white dwarfs, very dense stellar remnants that gradually cool and dim over billions of years. With their final few breaths before they collapse, however, these stars leave an important legacy, spreading their ashes into the surrounding space through stellar winds enriched with chemical elements, including carbon, newly synthesized in the star's deep interior during the last stages before its death.

Every carbon atom in the universe was created by stars, through the fusion of three helium nuclei. But astrophysicists still debate which types of stars are the primary source of the carbon in our own galaxy, the Milky Way. Some studies favor low-mass stars that blew off their envelopes in stellar winds and became white dwarfs, while others favor massive stars that eventually exploded as supernovae.

In the new study, published July 6, 2020, in Nature Astronomy, an international team of astronomers discovered and analyzed white dwarfs in open star clusters in the Milky Way, and their findings help shed light on the origin of the carbon in our galaxy. Open star clusters are groups of up to a few thousand stars, formed from the same giant molecular cloud and roughly the same age, and held together by mutual gravitational attraction.

The study was based on astronomical observations conducted in 2018 at the W. M. Keck Observatory in Hawaii and led by coauthor Enrico Ramirez-Ruiz, professor of astronomy and astrophysics at UC Santa Cruz. "From the analysis of the observed Keck spectra, it was possible to measure the masses of the white dwarfs. Using the theory of stellar evolution, we were able to trace back to the progenitor stars and derive their masses at birth," Ramirez-Ruiz explained.

The relationship between the initial masses of stars and their final masses as white dwarfs is known as the initial-final mass relation, a fundamental diagnostic in astrophysics that integrates information from the entire life cycles of stars, linking birth to death. In general, the more massive the star at birth, the more massive the white dwarf left at its death, and this trend has been supported on both observational and theoretical grounds.

But analysis of the newly discovered white dwarfs in old open clusters gave a surprising result: the masses of these white dwarfs were notably larger than expected, putting a "kink" in the initial-final mass relation for stars with initial masses in a certain range.

Millions of people take approx. 5 or more medications a day — but testing the many side-effects of those pharmaceutical drug combinations has historically been difficult. Researchers at Stanford Univ. have invented a way to predict side-effects using computer modeling based-on artificial intelligence. The team explained that most drug combinations (called poly-pharmacy) have never been systematically studied.

Their AI software system is called Decagon — and they say it can help physicians make better decisions about what drugs to prescribe. It could also help researchers find better combinations of prescription drugs to treat complex diseases.

Limited knowledge.

With so many prescription drugs currently on the pharmaceutical market: “it’s practically impossible to test a new drug in combination with all other drugs — because just for one drug that would be 5,000 new experiments,” said Marinka Zitnik PhD — a researcher on the project.

Zitnik said: “With some new drug combinations we don’t know what will happen.” The researchers explained that poly-pharmacy side-effects happen because of drug -to- drug interactions — the effects of one pharmaceutical drug may change (positively or negatively) if it’s taken with another drug.

The knowledge of medical drug interactions is often limited — because the complex relationships between many pharmaceutical combinations is only rarely observed. Discovering poly-pharmacy side-effects is a serious challenge that’s important for patient health.

Tracking how pharmaceutical drugs affect proteins

The researchers created a data-base containing descriptions of how 19,000+ proteins found in the human body interact with each other — and how various drugs affect these proteins. Using 4+ million known associations between drugs and their side-effects, the team crafted a method to identify patterns in how side-effects arise — based-on the way pharmaceutical drugs interact with proteins.

With that method, the system could predict the outcome of taking 2 drugs together. To evaluate their method, the group looked to see if its predictions came true. In many cases, they did. For example: there was no existing indication that the combination of a cholesterol drug named Lipitor and a blood-pressure medication called Norvasc, could lead to muscle inflammation. But Decagon predicted that it would, and that foresight was proven correct.

Life as we know it could not exist without Earth's magnetic field and its ability to deflect dangerous ionizing particles from the solar wind and more far-flung cosmic rays. It is continuously generated by the motion of liquid iron in Earth's outer core, a phenomenon called the geodynamo.

Despite its fundamental importance, many questions remain unanswered about the geodynamo's origin and the energy sources that have sustained it over the millennia.

New work from an international team of researchers, including current and former Carnegie scientists Alexander Goncharov, Nicholas Holtgrewe, Sergey Lobanov, and Irina Chuvashova examines how the presence of lighter elements in the predominately iron core could affect the geodynamo's genesis and sustainability. Their findings are published by Nature Communications.

Our planet accreted from the disk of dust and gas that surrounded our Sun in its youth. Eventually, the densest material sank inward in the forming planet, creating the layers that exist today -- core, mantle, and crust. Although, the core is predominately iron, seismic data indicates that some lighter elements like oxygen, silicon, sulfur, carbon, and hydrogen, were dissolved into it during the differentiation process.

Over time, the inner core crystallized and has been continuously cooling since then. On its own, could heat flowing out of the core and into the mantle drive the geodynamo? Or does this thermal convection need an extra boost from the buoyancy of light elements, not just heat, moving out of a condensing inner core?

Understanding the specifics of the core's chemical composition can help answer this question.

Silicates are predominant in the mantle, and after oxygen and iron, silicon is the third-most-abundant element in the Earth, so it is a likely option for one of the main lighter elements that could be alloyed with iron in the core. Led by Wen-Pin Hsieh of Academia Sinica and National Taiwan University, the researchers used lab-based mimicry of deep Earth conditions to simulate how the presence of silicon would affect the transmission of heat from the planet's iron core out into the mantle.

"The less thermally conductive the core material is, the lower the threshold needed to generate the geodynamo," Goncharov explained. "With a low enough threshold, the heat flux out of the core could be driven entirely by the thermal convection, with no need for the additional movement of material to make it work."

The WSU team’s findings suggest that Washingtonians who live in highly walkable, mixed‑age communities may be more likely to live to their 100th birthday.

When it comes to living to the ripe old age of 100, good genes help but don’t tell the full story. Where you live has a significant impact on the likelihood that you will reach centenarian age, suggests a new study conducted by scientists at Washington State University’s Elson S. Floyd College of Medicine.

Published in the International Journal of Environmental Research and Public Health and based on Washington State mortality data, the research team’s findings suggest that Washingtonians who live in highly walkable, mixed-age communities may be more likely to live to their 100th birthday. They also found socioeconomic status to be correlated, and an additional analysis showed that geographic clusters where the probability of reaching centenarian age is high are located in urban areas and smaller towns with higher socioeconomic status, including the Seattle area and the region around Pullman, Washington.

The current global health threat by the novel coronavirus disease 2019 (COVID-19) requires an urgent deployment of advanced therapeutic options being widely available. The role of nanotechnology is highly relevant to counter this viral nano enemy. Nano intervention is discussed in terms of designing effective nanocarriers to counter the conventional limitations of antiviral and biological therapeutics. This strategy directs the safe and effective delivery of available therapeutic options using engineered nanocarriers, blocking the initial interactions of viral spike glycoprotein with host cell surface receptors, and disruption of virion construction. Controlling and eliminating the spread and reoccurrence of this pandemic demands a safe and effective vaccine strategy. Nanocarriers have potential to design risk-free and effective immunization strategies for severe acute respiratory syndrome coronavirus 2 vaccine candidates such as protein constructs and nucleic acids. Ongoing nanotechnology-based therapeutic and prophylactic strategies to fight against this pandemic, outlining key areas, are being discussed.

A unique nanoparticle to deliver a localized cancer treatment inhibits tumor growth in mice, according to a team of Penn State researchers.

The nanoparticles, developed by Daniel Hayes, associate professor of biomedical engineering, have a specific chemistry that allows a microRNA (miRNA) to attach to it. A miRNA is a molecule that when paired to a messenger RNA (mRNA) prevents it from operating. In this case, it prohibits the mRNA in a cancer cell from creating proteins, which are essential for that cancer cell to survive.

In their study, the researchers delivered nanoparticles to the cancer cells of mice through an IV. Once the nanoparticles built up in the cancerous area, they used a specific wavelength of light to separate the miRNA from the nanoparticles. The miRNA then pairs with a mRNA in the cancer cell, causing the mRNA to stop making proteins. Eventually, the cancer cell dies.

Their paper is published on June 22, 2020 in the journal Biomaterials. "This delivery method gives you temporal and spatial specificity," said Adam Glick, professor of molecular toxicology and carcinogenesis. "Instead of having systemic delivery of a miRNA and the associated side effects, you are able to deliver the miRNA to a specific area of tissue at a specific time by exposing it to light."

Do signals from beneath an Italian mountain herald a revolution in physics?

In a paper that made the cover of the journal Applied Physics Letters ("Thin plate compression of a sub-petawatt Ti:Sa laser pulses"), an international team of researchers has demonstrated an innovative technique for increasing the intensity of lasers. This approach, based on the compression of light pulses, would make it possible to reach a threshold intensity for a new type of physics that has never been explored before: quantum electrodynamics phenomena.

Researchers Jean-Claude Kieffer of the Institut national de la recherche scientifique (INRS), E. A. Khazanov of the Institute of Applied Physics of the Russian Academy of Sciences and in France Gérard Mourou, Professor Emeritus of the Ecole Polytechnique, who was awarded the Nobel Prize in Physics in 2018, have chosen another direction to achieve a power of around 1023 Watts (W). Rather than increasing the energy of the laser, they decrease the pulse duration to only a few femtoseconds. This would keep the system within a reasonable size and keep operating costs down.

To generate the shortest possible pulse, the researchers are exploiting the effects of non-linear optics. “A laser beam is sent through an extremely thin and perfectly homogeneous glass plate. The particular behaviour of the wave inside this solid medium broadens the spectrum and allows for a shorter pulse when it is recompressed at the exit of the plate,” explains Jean-Claude Kieffer, co-author of the study.

Installed in the Advanced Laser Light Source (ALLS) facility at INRS, the researchers limited themselves to an energy of 3 joules for a 10-femtosecond pulse, or 300 terawatts (1012W). They plan to repeat the experiment with an energy of 13 joules over 5 femtoseconds, or an intensity of 3 petawatts (1015 W). “We would be among the first in the world to achieve this level of power with a laser that has such short pulses,” says Professor Kieffer.

“If we achieve very short pulses, we enter relativistic problem classes. This is an extremely interesting direction that has the potential to take the scientific community to new horizons,” says Professor Kieffer. “It was a very nice piece of work solidifying the paramount potential of this technique,” concludes Gérard Mourou".

Researchers at Carnegie Mellon University have developed a method for self-assembling nanostructures with gamma-modified peptide nucleic acid (γPNA), a synthetic mimic of DNA. The process has the potential to impact nanomanufacturing, as well as future biomedical technologies like targeted diagnostics and drug delivery. 

Published in Nature Communications, the work introduces a science of γPNA nanotechnology that enables self-assembly in organic solvent solutions, the harsh environments used in peptide and polymer synthesis. This holds promise for nanofabrication and nanosensing.

The research team, led by Rebecca Taylor, an assistant professor of mechanical engineering, reported that γPNA can form nanofibers in organic solvent solutions that can grow up to 11 microns in length (more than 1,000 times longer than their width). These represent the first complex, all-PNA nanostructures to be formed in organic solvents.

Taylor, who heads the heads the Microsystems and MechanoBiology Lab at Carnegie Mellon, wants to leverage PNA’s “superpowers.” In addition to its higher thermal stability, γPNA retains the ability to bind to other nucleic acids in organic solvent mixtures that would typically destabilize structural DNA nanotechnology. This means that they can form nanostructures in solvent environments that prevent formation of DNA-based nanostructures.  

RT-PCR tests for viral detection were the first available clinical tests, though scaling up their production and availability has been a persistent challenge in many countries. Important testing advances have included the development of saliva-based protocols and loop-mediated isothermal amplification protocols for SARS-CoV-2 detection. Serological testing for SARS-CoV-2 received an early boost by the development and sharing of reagents by the Krammer lab at Mount Sinai, New York.

Drug repurposing

The rapid spread of COVID-19, which by March had led to nationwide lockdowns in Italy and Spain, spurred attempts at drug repurposing. On 22 March, the WHO launched SOLIDARITY, a global trial of four therapies: the RNA polymerase inhibitor remdesivir, chloroquine and hydroxychloroquine (this arm has now been stopped), the HIV protease inhibitor combination lopinavir and ritonavir (results so far are not encouraging), and lopinavir-ritonavir plus interferon beta (which has shown reduced viral shedding and alleviated symptoms in one open-label trial). At time of writing, two drugs have been shown to be effective in clinical trials, remdesivir and the corticosteroid dexamethasone. In randomized control trials, remdesivir shortened the length of hospitalisation, but did not have a significant impact on mortality; dexamethasone significantly reduced mortality in patients requiring supplemental oxygen.

Candidate vaccines

By April, human trials were underway for several vaccine candidates, including established approaches like inactivated SARS-CoV-2 preparations as well as more recent strategies such as RNA- and adenoviral-derived products. Early results on safety and immunogenicity are already available for some of these, with Moderna announcing that its RNA SARS-CoV-2 vaccine induced a specific antibody response in phase I trials, and CanSino also showing specific antibody induction by its adenovirus-based vaccine. Passive immunization is also being pursued by various means, including convalescent plasma, hyperimmune serum preparations and the development of SARS-CoV-2-specific monoclonal antibodies.

It’s an approach officials are considering for ramping up coronavirus testing.

Solar power has become a focal point of the battle to mitigate climate change.  The potential of solar power is massive – Earth receives as much solar energy in an hour as all of humanity uses in a year.  Even with that much energy hitting the Earth, it is only a tiny fraction of the sun’s overall output.  Some of that other solar energy hits other planets, but most is just lost to the void of deep space.

There are a number of groups that are leveraging various technologies to capture some of that lost energy.  One of the most common technologies being pursued is the idea of the power satellite.  Recently, one of those groups at America’s Naval Research Laboratory (NRL) hit a milestone in the development of power satellite technology by launching their Photovoltaic RF Antenna Module (PRAM) test satellite.

The idea underlying power satellites is called “power beaming”.  Power beaming systems use one of three different frequencies of light to transmit significant amounts of power over a distance wirelessly.  Last year NRL had a successful demonstration of a land-based power beaming system using an infrared laser.

New observations could challenge previous theories of how the Moon was formed.

Life on Earth would not be possible without the Moon; it keeps our planet's axis of rotation stable, which controls seasons and regulates our climate. However, there has been considerable debate over how the Moon was formed. The popular hypothesis contends that the Moon was formed by a Mars-sized body colliding with Earth's upper crust which is poor in metals. But new research suggests the Moon's subsurface is more metal-rich than previously thought, providing new insights that could challenge our understanding of that process.

Now, a study published in Earth and Planetary Science Letters sheds new light on the composition of the dust found at the bottom of the Moon's craters. Led by Essam Heggy, research scientist of electrical and computer engineering at the USC Viterbi School of Engineering, and co-investigator of the Mini-RF instrument onboard NASA Lunar Reconnaissance Orbiter (LRO), the team members of the Miniature Radio Frequency (Mini-RF) instrument on the Lunar Reconnaissance Orbiter (LRO) mission used radar to image and characterize this fine dust. The researchers concluded that the Moon's subsurface may be richer in metals (i.e. Fe and Ti oxides) than scientists had believed.

According to the researchers, the fine dust at the bottom of the Moon's craters is actually ejected materials forced up from below the Moon's surface during meteor impacts. When comparing the metal content at the bottom of larger and deeper craters to that of the smaller and shallower ones, the team found higher metal concentrations in the deeper craters.

Scientists from various universities were able to set an extremely high record of squeezing 44.2 terabits per second of data through an existing fiber optic cable. This new world record was achieved by using a so-called 'micro-comb,' which is capable of firing several laser beams in a bundle.

The worldwide optical fiber network currently has a capacity of many hundreds of terabits per second, a capacity that grows at an annual rate of approximately 25%. Its focus has been shifting from long-haul communication, spanning many thousands of kilometers, to numerous shorter-high-capacity connections for so-called metro-area networks. 

These local networks handle data transfers at distances between 10 kilometers to about 100 kilometers. At these distances, there is a need for increasingly compact, energy-efficient and low-cost solutions. The researchers think that their medium-range, ultra-fast micro-comb solution will be able to play a beneficial role here. 

Japanese researchers have turned to the world's fastest supercomputer to help test the effectiveness of different COVID-19 mitigation tactics.

The Tokyo-based scientific research institute Riken devised a series of complex simulations to observe how SARS-CoV-2 might spread indoors, and created a list of suggestions to limit transmission based on those simulations.

The researchers enlisted Fugaku, the $1billion supercomputer that was crowned the world's fastest supercomputer in June, to conduct the simulations.

Fugaku features 158,976 custom ARM processors, each of which have 48 CPU cores, and which can collectively process 415.5 petaflops a second, almost three times as much as the previous fastest computer in the world. The team used Fugaku to simulate how air particles that an infected person might cough out would travel through the air in an enclosed space, according to a report from 

The Asahi Shimbun.Using a base assumption that every cough releases around 50,000 particles that range in size between one micrometer and several hundred micrometers, they simulated the likelihood of another person inhaling one of those particles in a variety of different circumstances.

The team, led by Makoto Tsuobokura, concluded that one of the effective solutions was also one of the cheapest and involved simply opening windows.

According to a simulation of commuter train car, just opening the windows increased ventilation by between two and three times and substantially lowered the amount of microbes in the air.

The simulation also showed that limiting the number of passengers in each car would lower transmission even further.

For hospitals, the simulation suggested the optimal solution would be floor to ceiling curtains that completely enclose potentially infected patients.

Like a scene out of "Invasion of the Body Snatchers," a virus infects a host and converts it into a factory for making more copies of itself. Now researchers have shown that a large group of viruses, including the influenza viruses and other serious pathogens, steal genetic signals from their hosts to expand their own genomes.

This finding is presented in a study published June 25th, 2020 in Cell. The cross-disciplinary collaborative study was led by researchers at the Global Health and Emerging Pathogens Institute at Icahn School of Medicine at Mount Sinai in New York, and at the MRC-University of Glasgow Centre for Virus Research in the UK.

The cross-disciplinary team of virologists looked at a large group of viruses known as segmented negative-strand RNA viruses (sNSVs), which include widespread and serious pathogens of humans, domesticated animals and plants, including the influenza viruses and Lassa virus (the cause of Lassa fever). They showed that, by stealing genetic signals from their hosts, viruses can produce a wealth of previously undetected proteins. The researchers labeled them as UFO (Upstream Frankenstein Open reading frame) proteins, as they are encoded by stitching together the host and viral sequences. There was no knowledge of the existence of these kinds of proteins prior to this study.

Many animals, including dogs, cats and various species of monkeys, will move their ears to better focus their attention on a novel sound. That humans also have this capability was not known until now. A research team based in Saarland, Germany, has demonstrated for the first time that we make minute, unconscious movements of our ears that are directed towards the sound want to focus our attention on. The team discovered this ability by measuring electrical signals in the muscles of the vestigial motor system in the human ear. The results have now been published in the journal eLife.

Asking children to 'perk up their ears' means asking them to listen intently. Nobody seriously thinks that kids literally move their ears the way that cats, dogs or horses do. But the fact is, they do, as researchers at the Systems Neuroscience & Neurotechnology Unit (SNNU) have now shown. The research team, led by Professor Danial Strauss, has shown that the muscles around the ear become active as soon as novel, unusual or goal-relevant sounds are perceived.

'The electrical activity of the ear muscles indicates the direction in which the subject is focusing their auditory attention,' says neuroscientist and computer scientist Strauss. 'It is very likely that humans still possess a rudimentary orientation system that tries to control the movement of the pinna (the visible outer part of the ear). Despite becoming vestigial about 25 million years ago, this system still exists as a "neural fossil" within our brains,' explains Professor Strauss.

Scientists estimate that less than 1 percent of small molecules are known. A typical commercially available metabolomics library has maybe 5,000 compounds, but scientists know there are billions more. How do they “identify” something about which they know so little? It’s like asking Galileo to identify stars in deep space that were impossible to detect when he used one of the first telescopes more than 400 years ago.

Enter DarkChem, a research project funded by PNNL’s Deep Learning for Scientific Discovery Agile Investment. A team led by Ryan Renslow is bringing artificial intelligence to the table to tackle the vast, unknown landscape of metabolites that bedevil researchers like Tom Metz, who leads PNNL’s metabolomics effort.

 “Right now, we’re just skimming what is potentially knowable and saying goodbye to very interesting data because we can’t identify the vast majority of metabolites that our technology detects,” said Metz. “Deep learning is providing a new way to solve the puzzle.”

Renslow and colleagues Sean Colby and Jamie Nunez have adopted deep learning principles commonly used in applications like language translation and applied them to this dark matter of the molecular world.

Early results are noteworthy: The team’s DarkChem network can calculate a key feature of a molecule in milliseconds and with 13 percent fewer errors, compared to 40 hours on a supercomputer running PNNL’s flagship quantum chemistry software, NWChem. “We were shocked at how well DarkChem did,” said Renslow.

The network isn’t simply crunching through data to compile results. Rather, the network draws upon artificial intelligence. DarkChem was developed so that it can discover new things that are still unknown to humans.

Renslow and his team trained DarkChem to calculate CCS for chemical structures, then turned it loose to make the calculation for more than 50 million compounds – a portion of the library of PubChem. The program solved that task in a snap.

A Bristol academic has achieved a milestone in statistical/mathematical physics by solving a 100-year-old physics problem—the discrete diffusion equation in finite space.

The long-sought-after solution could be used to accurately predict encounter and transmission probability between individuals in a closed environment, without the need for time-consuming computer simulations.

In a recent paper, published in Physical Review X, Dr. Luca Giuggioli from the Department of Engineering Mathematics at the University of Bristol describes how to analytically calculate the probability of occupation (in discrete time and discrete space) of a diffusing particle or entity in a confined space—something that until now was only possible computationally.

Dr. Giuggioli said: "The diffusion equation models random movement and is one of the fundamental equations of physics. The analytic solution of the diffusion equation in finite domains, when time and space is continuous, has been known for a long time.

"However, to compare model predictions with empirical observations, one needs to study the diffusion equation in finite space. Despite the work of illustrious scientists such as Smoluchowski, Pólya, and other investigators of yore, this has remained an outstanding problem for over a century—until now.

"Excitingly, the discovery of this exact analytic solution allows us to tackle problems that were almost impossible in the past because of the prohibitive computational costs."

A 50-year-old theory that began as speculation about how an alien civilization could use a black hole to generate energy has been experimentally verified for the first time in a Glasgow research lab.

In 1969, British physicist Roger Penrose suggested that energy could be generated by lowering an object into the black hole’s ergosphere – the outer layer of the black hole’s event horizon, where an object would have to move faster than the speed of light in order to remain still.

Penrose predicted that the object would acquire a negative energy in this unusual area of space. By dropping the object and splitting it in two so that one half falls into the black hole while the other is recovered, the recoil action would measure a loss of negative energy – effectively, the recovered half would gain energy extracted from the black hole’s rotation.

The scale of the engineering challenge the process would require is so great, however, that Penrose suggested only a very advanced, perhaps earthbound experiment. He proposed that ’twisted’ light waves, hitting the surface of a rotating metal cylinder turning at just the right speed, would end up being reflected with additional energy extracted from the cylinder’s rotation thanks to a quirk of the rotational Doppler effect.

But Zel’dovich’s idea has remained solely in the realm of theory since 1971 because, for the experiment to work, his proposed metal cylinder would need to rotate at least a billion times a second – another insurmountable challenge for the current limits of human engineering. 

Now, researchers from the University of Glasgow’s School of Physics and Astronomy have finally found a way to experimentally demonstrate the effect that Penrose and Zel’dovich proposed by twisting sound instead of light – a much lower frequency source, and thus much more practical to demonstrate in the lab.

Bas Uterwijk, an Amsterdam-based artist, is using AI to create extremely lifelike photographs of historical figures and monuments such as the Statue of Liberty, artist Vincent van Gogh, George Washington and Queen Elizabeth I.

Using a program called Artbreeder, which is described as “deep learning software,” Uterwijk builds his photographs based on a compilation of portraits, reports the Daily Mail. The program pinpoints common facial features and photograph qualities to produce an image.

“I try to guide the software to a credible outcome. I think of my work more as artistic interpretations than scientifically or historically accurate,” the artist tells the outlet. On Instagram, he details the many variations that go into creating his work. So far, he’s created more than 50 of these images.

Unprecedented details of enamel structure may point to new ways to prevent or halt cavities.

Scientists used a combination of advanced microscopy and chemical detection techniques to uncover the structural makeup of human tooth enamel at unprecedented atomic resolution, revealing lattice patterns and unexpected irregularities. The findings could lead to a better understanding of how tooth decay develops and might be prevented. The research was supported in part by the National Institute of Dental and Craniofacial Research (NIDCR) at the National Institutes of Health. The findings appear in Nature.

“This work provides much more detailed information about the atomic makeup of enamel than we previously knew,” said Jason Wan, Ph.D., a program officer at NIDCR. “These findings can broaden our thinking and approach to strengthening teeth against mechanical forces, as well as repairing damage due to erosion and decay.”

Your teeth are remarkably resilient, despite enduring the stress and strain of biting, chewing, and eating for a lifetime. Enamel — the hardest substance in the human body — is largely responsible for this endurance. Its high mineral content gives it strength. Enamel forms the outer covering of teeth and helps prevent tooth decay, or caries.

Tooth decay is one of the most common chronic diseases, affecting up to 90% of children and the vast majority of adults worldwide, according to the World Health Organization. Left untreated, tooth decay can lead to painful abscesses, bone infection, and bone loss.

Tooth decay starts when excess acid in the mouth erodes the enamel covering. Scientists have long sought a more complete picture of enamel’s chemical and mechanical properties at the atomic level to better understand—and potentially prevent or reverse—enamel loss. To survey enamel at the tiniest scales, researchers use microscopy methods such as scanning transmission electron microscopy (STEM), which directs a beam of electrons through a material to map its atomic makeup.

For all the mysteries that remain about the novel coronavirus SARS-CoV-2 and the COVID-19 disease it causes, scientists have generated an incredible amount of fine-grained knowledge in a surprisingly short time. Scientific American presents detailed explanations, current as of mid-June, into how SARS-CoV-2 sneaks inside human cells, makes copies of itself and bursts out to infiltrate many more cells, widening infection. This review shows how the immune system would normally attempt to neutralize virus particles and how CoV-2 can block that effort. This review explains some of the virus' surprising abilities, such as its capacity to proofread new virus copies as they are being made to prevent mutations that could destroy them. This review also shows how drugs and vaccines might still be able to overcome the intruders. As virologists learn more, this review will be updated on the Scientific American Web site (www.scientificamerican.com).

Commercial and university labs are investigating well over 100 drugs to fight COVID-19, the disease the SARS-CoV-2 virus causes. Most drugs would not destroy the virus directly but would interfere with it enough to allow the body's immune system to clear the infection. Antiviral drugs generally stop a virus from attaching to a lung cell, prevent a virus from reproducing if it does invade a cell, or dampen an overreaction by the immune system, which can cause severe symptoms in infected people. Vaccines prepare the immune system to quickly and effectively fight a future infection.

Primates’ neural computations shed new light on the evolution of language. Humans and monkeys may not speak the same lingo, but our ways of thinking are a lot more similar than previously thought, according to new research from UC Berkeley, Harvard University and Carnegie Mellon University.

In experiments on 100 study participants across age groups, cultures and species, researchers found that indigenous Tsimane’ people in Bolivia’s Amazon rainforest, American adults and preschoolers and macaque monkeys all show, to varying degrees, a knack for “recursion,” a cognitive process of arranging words, phrases or symbols in a way that helps convey complex commands, sentiments and ideas.

The findings, published in the journal Science Advances, shed new light on our understanding of the evolution of language, researchers said. “For the first time, we have strong empirical evidence about patterns of thinking that come naturally to probably all humans and, to a lesser extent, non-human primates,” said study co-author Steven Piantadosi, a UC Berkeley assistant professor of psychology.

Indeed, the monkeys were found to perform far better in the tests than the researchers had predicted. “Our data suggest that, with sufficient training, monkeys can learn to represent a recursive process, meaning that this ability may not be as unique to humans as is commonly thought,” said Sam Cheyette, a Ph.D. student in Piantadosi’s lab and co-author of the study.