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Feb 27, 2023

New strategy proposed for bandgap engineering and maintaining material properties under high pressure

Posted by in categories: engineering, materials

Prof. Ding Junfeng and his team from the Hefei Institutes of Physical Science (HFIPS) of the Chinese Academy of Science, together with Prof. Zhang Genqiang from the University of Science and Technology of China, have achieved band gap optimization and photoelectric response enhancement of carbon nitride in the nitrogen vacancy graphite phase under high pressure.

Their results were published in the journal Physical Review Applied.

Graphitic carbon nitride (g-C3N4) has performed well in many fields, such as high-efficiency photocatalytic hydrogen production and water oxidation. However, the wide band gap of 2.7 eV of the original g-C3N4 limits its light absorption in the visible region. High technology is an to change the properties while remaining composition. Therefore, band gap engineering of g-C3N4 by high-pressure technology can significantly enhance its photocatalytic activity and improve its application potential.

Feb 27, 2023

Strong microwave magnetic fields for more efficient plasmas

Posted by in categories: chemistry, particle physics

Hot gases composed of metal ions and electrons, called plasmas, are widely used in many manufacturing processes, chemical synthesis, and metal extraction from ores and welding. A collaborative research group from Tohoku University and the Toyohashi University of Technology has invented a new and efficient method to create metallic plasmas from solid metals under a strong magnetic field in a microwave resonator. They report their innovation in the journal AIP Advances.

In the most conventional methods for making plasmas, a strong electric field is applied to gases or liquids. This can require enormous amounts of energy. More recently, has also been harnessed to generate plasmas as it converts atoms into a form that can more effectively drive desired , among other advantages. The plasmas generated by microwaves are now being used in commercial processes, including semiconductor manufacture, diamond deposition and to release metals from their ores.

Until now, however, this has involved multi-mode microwave generators, which generate a chaotic distribution of microwaves. One key advance achieved by the team is to apply a single-mode microwave generator to produce their metal plasmas. This creates more controlled and highly focused microwaves.

Feb 27, 2023

Shape-shifting experiment challenges interpretation of how cadmium nuclei move

Posted by in category: physics

Atomic nuclei take a range of shapes, from spherical (like a basketball) to deformed (like an American football). Spherical nuclei are often described by the motion of a small fraction of the protons and neutrons, while deformed nuclei tend to rotate as a collective whole.

A third kind of motion has been proposed since the 1950s. In this motion, known as nuclear vibration, fluctuate about an average shape. Scientists recently investigated cadmium-106 using a technique called Coulomb excitation to probe its . They found clear experimental evidence that the vibrational description fails for this isotope’s nucleus. This finding is counter to the expected results.

Research published in Physics Letters B builds on a long quest to understand the transition between spherical and deformed . This transition often includes vibrational motion as an intermediate step. The new result suggests that may need to revise the long-standing paradigm describing how this transition occurs.

Feb 27, 2023

Recognizing a clear sign that quark-gluon plasma production ‘turns off’ at low energy

Posted by in categories: nuclear energy, particle physics

Physicists report new evidence that production of an exotic state of matter in collisions of gold nuclei at the Relativistic Heavy Ion Collider (RHIC)—an atom-smasher at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory—can be “turned off” by lowering the collision energy. The “off” signal shows up as a sign change—from negative to positive—in data that describe “higher order” characteristics of the distribution of protons produced in these collisions.

The findings, just published by RHIC’s STAR Collaboration in Physical Review Letters, will help physicists map out the conditions of temperature and density under which the exotic matter, known as a quark-gluon plasma (QGP), can exist and identify key features of the phases of nuclear matter.

Generating and studying QGP has been a central goal of research at RHIC. Since the collider began operating in 2000, a wide range of measurements have shown that the most energetic smashups of atomic nuclei—at 200 billion electron volts (GeV)— melt the boundaries of protons and neutrons to set free, for a fleeting instant, the quarks and gluons that make up ordinary nuclear particles.

Feb 27, 2023

Researchers realize non-Hermitian exceptional points in degenerate optical cavity

Posted by in categories: energy, physics, space

Recently, a research team led by Prof. Guo Guangcan from the University of Science and Technology of China (USTC) constructed a non-Hermiticity (NH) synthetic orbital angular momentum (OAM) dimension in a degenerate optical cavity and observed the exceptional points (EPs). This study was published in Science Advances.

In topological physics, the NH systems depict open systems with complex spectra. Exceptional points are one of the unique features of NH systems. To study EPs, the team had constructed synthetic one-dimensional lattices and established topological simulation platform in a degenerate optical cavity. Based on this platform, an additional pseudomomentum was introduced as a parameter to construct the Dirac point in the two-dimensional momentum space. A pair of EPs can be obtained by introducing non-Hermitian perturbation around the Dirac point.

The detection of complex energy spectra in NH systems can be troublesome for traditional means. The research group developed a method which is referred to as wave front angle–resolved band structure spectroscopy to investigate complex energy spectra based on synthetic OAM. Using this method, the team not only detected EPs in momentum space, but also the key features of EPs like bulk Fermi arcs, parity-time symmetry-breaking transition, energy swapping and half-integer band windings.

Feb 27, 2023

VKORC1 single nucleotide polymorphisms in rodents in Spain

Posted by in categories: augmented reality, biotech/medical, food, genetics, health

Rodents are considered one of the animal pests with the greatest impact on agricultural production and public health, especially the brown or Norway rat (Rattus norvegicus), the black or roof rat (Rattus rattus) and the house mouse (Mus musculus). Its control is an increasing problem worldwide. The intensification of agricultural production methods as well as the increase in merchandise transport to sustain growing populations is leading to an increase in waste production causing the growth of these rodent populations. The estimated losses in crop production caused by rodents range from between 5% and 90% (Stenseth et al., 2003) and this can cause problems in food security during harvesting (Belmain et al., 2015). Other negative impacts result from some rodent species living very close to human environments that can have a direct influence not only on human health through potential transmission of gastroenteric diseases and zoonosis to householders but also on domestic livestock. Therefore, rodent pest control is crucial and nowadays, the only effective control method available is the use of anticoagulant rodenticides (ARs).

ARs are so named because they interfere with the blood coagulation processes. The processes of activating various coagulation factors depends on the amount of vitamin K in its reduced form that exists in the organism. ARs inhibit the enzyme vitamin K 2,3-epoxide reductase (VKORC1) that is responsible for reducing vitamin K and maintaining the balance between its oxidized and reduced forms. The inhibition of VKORC1 prevents the activation of the coagulation factors resulting in animal death by internal bleeding. However, the intensive use of ARs can cause rodents to lose their susceptibility and become resistant to them. Genetic resistances to ARs are mainly associated with mutations or single nucleotide polymorphisms (SNPs) in the gene that codes for VKORC1 (vkorc1), causing amino acid substitutions in the VKORC1 protein ( Pelz et al., 2005 ). There are studies on this topic in several countries of central and northern Europe detecting rodent populations resistant to AR. Currently, there are at least 13 mutations mainly located in the exon 3 of the vkorc1 gene described in various countries of the European Union that confer resistance to specific ARs ( Berny et al., 2014 ; Goulois et al., 2017 ). In Eastern and Southern European countries, the information on the incidence of resistances to rodenticides is scarce, and it is becoming increasingly important to generate information on this subject ( Berny et al., 2014). In Spain, a mice population at the coastal countryside showing an adaptive introgression between house mouse and Algerian mouse that confers anticoagulant resistance has been described ( Song et al., 2011 ). While recently, four VKORC1 mutations in black rat were found in Toledo, Segovia and Zaragoza ( Goulois et al., 2016 ; Damin-Pernik et al., 2022 ). Any increase in resistant in rodent populations would lead to pest control issues that may causing serious agricultural, farming and public health problems.

Scientific advances have revolutionized the study of anticoagulant resistances in terms of understanding their genetic basis, physiological mechanisms and geographical distribution. The techniques based on the extraction and partial sequencing of genomic DNA allow a fast and precise monitoring of possible genetic resistances. Most of these tests involve laboratory studies using live rodents or blood samples taken from animals in the field. However, the improvement of DNA extraction techniques now allows the analysis of faecal samples (stool), increasing the number of samples that can be taken without the need for sampling by trapping or the management of dead animals (Meerburg et al., 2014). The importance of initial detection of genetic resistances due to mutations is crucial. The hypothesis of work, presenting it as a null hypothesis, is that there will be no rodent mutations in the vkorc1 gene in Spain.

Feb 27, 2023

Scientists Prove Validity of Key Physics Theorem in the Quantum World

Posted by in categories: particle physics, quantum physics

The physicists at the University of Bonn have experimentally demonstrated that a crucial theorem in statistical physics is applicable to Bose-Einstein condensates. This discovery enables the measurement of specific properties of these quantum “superparticles,” providing a means of deducing system characteristics that would otherwise be challenging to observe. The findings of this study have been published in the journal Physical Review Letters.

Suppose in front of you there is a container filled with an unknown liquid. Your goal is to find out by how much the particles in it (atoms or molecules) move back and forth randomly due to their thermal energy. However, you do not have a microscope with which you could visualize these position fluctuations known as “Brownian motion”.

It turns out you do not need that at all: You can also simply tie an object to a string and pull it through the liquid. The more force you have to apply, the more viscous your liquid. And the more viscous it is, the lesser the particles in the liquid change their position on average. The viscosity at a given temperature can therefore be used to predict the extent of the fluctuations.

Feb 27, 2023

Researcher develops new methods to measure ‘forever chemicals’ in both the atmosphere and in aerosol particles

Posted by in categories: biotech/medical, chemistry, engineering, health

From regulators to researchers and most industries in between, all eyes are on PFAS, per-and polyfluoroalkyl substances, are a class of highly fluorinated human-made compounds that have been used for decades in everything from nonstick cookware and personal care products to fire-fighting foams and school uniforms. Their commonality and extreme resistance to environmental degradation has made them ubiquitous in ground water, soil, and worst of all humans. Linked to a slew of health risks including liver toxicity, bladder cancer, and decreased immune response to vaccinations, exposure to PFAS is concerning. So, how can we eliminate these “forever chemicals?”

Historically, PFAS substances have only been characterized in water and soil, but the emission of these compounds during chemical manufacturing, use, and disposal results in their emission into the air. Ryan Sullivan, Professor of Mechanical Engineering and Chemistry at Carnegie Mellon University, has been developing new methods to measure PFAS in both the atmosphere and in aerosol particles to answer outstanding questions regarding PFAS atmospheric components that lead to human exposure. His group is also developing new approaches to destroy forever molecules that are not removed by conventional water treatment plants.

The research is published in the journal Environmental Science: Processes & Impacts.

Feb 27, 2023

New testing approach diagnoses COVID-19 with near-perfect accuracy

Posted by in categories: biotech/medical, computing

Most existing COVID-19 tests “rely on the same principle, which is that you have accumulated a detectable amount of viral material, for example, in your nose,” says study lead author Frank Zhang, who worked on the project as a Flatiron research fellow at the Flatiron Institute’s Center for Computational Biology (CCB) in New York City. “That poses a challenge when it’s early in the infection time window and you haven’t accumulated a lot of viral material, or you’re asymptomatic.”

The new technique is instead based on how our bodies mount an when invaded by SARS-CoV-2, the virus that causes COVID-19. When the assault starts, specific genes turn on. Segments of those genes produce mRNA molecules that guide the building of proteins. The particular blend of those mRNA molecules changes the types of proteins produced, including proteins involved in virus-fighting functions. The new method can confidently identify when the body is mounting an immune response to the COVID-19 virus by measuring the relative abundance of the various mRNA molecules. The new study is the first to use such an approach to diagnose an infectious disease.

Feb 27, 2023

The weight of responsibility: Biomass of livestock dwarfs that of wild mammals

Posted by in category: futurism

We often think that our world is an infinite realm comprising great plains, jungles and oceans, teeming with wild animals featured in memorable nature shows like the BBC’s Planet Earth. But the first global census of wild mammal biomass, conducted by Weizmann Institute of Science researchers and reported today in PNAS, reveals the extent to which our natural world—along with its most iconic animals—is a vanishing one.

The new report shows that the of wild mammals on land and at sea is dwarfed by the combined weight of cattle, pigs, sheep and other domesticated mammals. A team headed by Prof. Ron Milo found that the biomass of livestock has reached about 630 million tons—30 times the weight of all wild terrestrial mammals (approximately 20 million tons) and 15 times that of wild marine mammals (40 million tons).

An earlier, widely-discussed study in Nature by researchers in Milo’s lab in Weizmann’s Plant and Environmental Sciences Department showed that in 2020, the mass of human-made objects—anything from skyscrapers to newspapers—had surpassed the planet’s entire biomass, from redwood trees to honeybees. In the latest study, the researchers offer a new perspective on humanity’s rapidly increasing impact on our planet, seen in the ratio between humans and domesticated mammals, and wild mammals.