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Comment by Dr. Krishna Kumari Challa on February 1, 2024 at 7:37am

Study finds 1 in 10 veterans diagnosed with dementia may instead have cognitive decline from cirrhosis

As many as 10% of older U.S. veterans diagnosed with dementia may suffer instead from reversible cognitive decline caused by advanced liver disease, according to an analysis from the Virginia Commonwealth University's School of Medicine and the Richmond VA Medical Center.

It can be difficult for physicians to differentiate dementia from the cognitive decline caused by cirrhosis, called hepatic encephalopathy. If undetected, patients may not receive appropriate treatment that can reverse or halt the impairment. The study, published in the journal JAMA Network Open, sought to learn more about the prevalence and risk factors of undiagnosed cirrhosis and potential encephalopathy in veterans with dementia. The findings suggest that physicians treating veterans with dementia, even without a cirrhosis diagnosis, should consider assessing their patients for liver disease. Identifying cirrhosis early on may unveil reversible causes of cognitive impairment, potentially improving the lives of these patients.

Hepatic encephalopathy is a nervous system disorder brought on by cirrhosis, an advanced form of liver disease in which patients experience severe scarring of the liver. When the liver doesn't work properly, toxins build up in the blood. These toxins can travel to the brain and affect brain function, leaving patients confused or delirious. Widely available medications can readily rid the body of toxins and reverse this condition, but without treatment, patients can lapse into coma or die.

Undiagnosed Cirrhosis and Hepatic Encephalopathy in a National Cohort of Veterans With Dementia, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2023.53965

Comment by Dr. Krishna Kumari Challa on February 1, 2024 at 7:24am

How synthetic biology is helping us: Researchers engineer viruses to kill deadly pathogens

Researchers have successfully coaxed a deadly pathogen to destroy itself from the inside out.

In a new study, researchers modified DNA from a bacteriophage or "phage," a type of virus that infects and replicates inside of bacteria. Then, the research team put the DNA inside Pseudomonas aeruginosa (P. aeruginosa), a deadly bacterium that is also highly resistant to antibiotics. Once inside the bacterium, the DNA bypassed the pathogen's defense mechanisms to assemble into virions, which sliced through the bacterium's cell to kill it.

Building on a growing interest in "phage therapies," the experimental work represents a critical step toward engineering designer viruses as new therapeutics to kill antibiotic-resistant bacteria. It also reveals vital information about the inner workings of phages, a little-studied area of biology.

The study, "A synthetic biology approach to assemble and reboot clinically relevant Pseudomonas aeruginosa tailed phages," was published in the journal Microbiology Spectrum.

Not only did the phage kill the bacteria, the bacteria also ejected billions more phages. These phages can then be used to kill other bacteria, like those causing an infection.

A synthetic biology approach to assemble and reboot clinically relevant Pseudomonas aeruginosa tailed phages, Microbiology Spectrum (2024). DOI: 10.1128/spectrum.02897-23

Comment by Dr. Krishna Kumari Challa on February 1, 2024 at 7:16am

Brain changes behind pain sensitivity may affect older women more

A new study has found that the brain system enabling us to inhibit our own pain changes with age, and that gender-based differences in those changes may lead females to be more sensitive to moderate pain than males as older adults.

Researchers used fMRI scans to examine brain responses in men and women who had rated the intensity and unpleasantness of pain during exposure to increasing levels of heat. The results suggested that established gender differences in pain perception could likely be traced at least in part to this brain network, and offered new evidence that those gender differences may become more disparate with age.

Michelle D. Failla et al, Gender Differences in Pain Threshold, Unpleasantness, and Descending Pain Modulatory Activation Across the Adult Life Span: A Cross Sectional Study, The Journal of Pain (2023). DOI: 10.1016/j.jpain.2023.10.027

Comment by Dr. Krishna Kumari Challa on February 1, 2024 at 7:13am

Scientists pinpoint growth of brain's cerebellum as key to evolution of bird flight

Evolutionary biologists  report they have combined PET scans of modern pigeons along with studies of dinosaur fossils to help answer an enduring question in biology: How did the brains of birds evolve to enable them to fly?

The answer, they say, appears to be an adaptive increase in the size of the cerebellum in some fossil vertebrates. The cerebellum is a brain region responsible for movement and motor control.

The research findings are published in the Jan. 31 issue of the Proceedings of the Royal Society B.

The researchers performed positron emission tomography, or PET, imaging scans, the same technology commonly used on humans, to compare activity in 26 regions of the brain when the bird was at rest and immediately after it flew for 10 minutes from one perch to another. They scanned eight birds on different days. PET scans use a compound similar to glucose that can be tracked to where it's most absorbed by brain cells, indicating increased use of energy and thus activity. The tracker degrades and gets excreted from the body within a day or two. Of the 26 regions, one area—the cerebellum—had statistically significant increases in activity levels between resting and flying in all eight birds. Overall, the level of activity increase in the cerebellum differed by more than two standard statistical deviations, compared with other areas of the brain. The researchers also detected increased brain activity in the so-called optic flow pathways, a network of brain cells that connect the retina in the eye to the cerebellum. These pathways process movement across the visual field.

What was new in this research was linking the cerebellum findings of flight-enabled brains in modern birds to the fossil record that showed how the brains of birdlike dinosaurs began to develop brain conditions for powered flight.

Quantitative functional imaging of the pigeon brain: implications for the evolution of avian powered flight, Proceedings of the Royal Society B: Biological Sciences (2024). DOI: 10.1098/rspb.2023.2172. royalsocietypublishing.org/doi … .1098/rspb.2023.2172

Comment by Dr. Krishna Kumari Challa on February 1, 2024 at 7:05am

Neanderthals and humans lived side by side in Northern Europe 45,000 years ago, genetic analysis finds

A genetic analysis of bone fragments unearthed at an archaeological site in central Germany shows conclusively that modern humans—Homo sapiens—had already reached Northern Europe 45,000 years ago, overlapping with Neanderthals for several thousand years before the latter went extinct.

The findings establish that the site near Ranis, Germany, which is known for its finely flaked, leaf-shaped stone tool blades, is among the oldest confirmed sites of modern human Stone Age culture in north central and northwestern Europe.

The evidence that Homo sapiens and Homo neanderthalensis lived side by side is consistent with genomic evidence that the two species occasionally interbred. It also feeds the suspicion that the invasion of Europe and Asia by modern humans some 50,000 years ago helped drive Neanderthals, which had occupied the area for more than 500,000 years, to extinction.

The genetic analysis, along with an archaeological and isotopic analysis and radiocarbon dating of the Ranis site, are detailed in a trio of papers appearing in the journals Nature and Nature Ecology and Evolution.

Jean-Jacques Hublin, Homo sapiens reached the higher latitudes of Europe by 45,000 years ago, Nature (2024). DOI: 10.1038/s41586-023-06923-7. www.nature.com/articles/s41586-023-06923-7

Stable isotopes show Homo sapiens dispersed into cold steppes ~45,000 years ago at Ilsenhöhle in Ranis, Germany, Nature (2024). DOI: 10.1038/s41559-023-02318-z , www.nature.com/articles/s41559-023-02318-z

The ecology, subsistence and diet of ~45,000-year-old Homo sapiens at Ilsenhöhle in Ranis, Germany, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-023-02303-6 , www.nature.com/articles/s41559-023-02303-6

https://phys.org/news/2024-01-neanderthals-humans-side-northern-eur...

Comment by Dr. Krishna Kumari Challa on January 31, 2024 at 12:13pm

Study finds gut microbiota influence severity of respiratory viral infection

The composition of microbiota found in the gut influences how susceptible mice are to respiratory virus infections and the severity of these infections, according to new research by researchers.

The findings, published in the journal Cell Host & Microbe, report that segmented filamentous bacteria, a bacterial species found in the intestines, protected mice against influenza virus infection when these bacteria were either naturally acquired or administered.

This protection against infection also applied to respiratory syncytial virus (RSV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. To maintain this protection, the study noted that segmented filamentous bacteria required immune cells in the lungs called basally resident alveolar macrophages.

In this study, the researchers investigated how differences in specific microbial species can impact outcomes of respiratory virus infections and how they might do so, which hasn't been well defined previously. They studied mice with discrete microbiome differences and mice differing in only the presence or absence of segmented filamentous bacteria. Viral titers in the lung were measured several days after infection and varied significantly depending on the nature of the microbiome of the different animal groups.

These findings uncover complex interactions that mechanistically link the intestinal microbiota with the functionality of basally resident alveolar macrophages and severity of respiratory virus infection.

Intestinal microbiota programming of alveolar macrophages influences severity of respiratory viral infection, Cell Host & Microbe (2024). DOI: 10.1016/j.chom.2024.01.002. www.cell.com/cell-host-microbe … 1931-3128(24)00006-4

Comment by Dr. Krishna Kumari Challa on January 31, 2024 at 12:06pm

DNA particles that mimic viruses hold promise as vaccines

Using a virus-like delivery particle made from DNA, researchers have created a vaccine that can induce a strong antibody response against SARS-CoV-2.

The vaccine, which has been tested in mice, consists of a DNA scaffold that carries many copies of a viral antigen. This type of vaccine, known as a particulate vaccine, mimics the structure of a virus. Most previous work on particulate vaccines has relied on protein scaffolds, but the proteins used in those vaccines tend to generate an unnecessary immune response that can distract the immune system from the target.

In the mouse study, the researchers found that the DNA scaffold does not induce an immune response, allowing the immune system to focus its antibody response on the target antigen.

This approach, which strongly stimulates B cells (the cells that produce antibodies), could make it easier to develop vaccines against viruses that have been difficult to target, including HIV and influenza, as well as SARS-CoV-2, the researchers say. Unlike T cells, which are stimulated by other types of vaccines, these B cells can persist for decades, offering long-term protection.

Enhancing antibody responses by multivalent antigen display on thymusindependent DNA origami scaffolds, Nature Communications (2024). DOI: 10.1038/s41467-024-44869-0

Comment by Dr. Krishna Kumari Challa on January 30, 2024 at 12:11pm

Brains Not Required
Simple cells, not just highly specialized neurons, can exhibit basic cognitive abilities such as memory, learning, and problem-solving. Tufts University biologist Michael Levin trained flatworms to expect yummy liver treats at a certain location in their dish. Even after he decapitated the worms (don’t worry! They regrew their heads), the worms could remember where to go for a liver snack. Researchers suspect that body cells are able to use weak electric fields to store information.

Why this is so cool: Plants, slime molds, and single-celled organisms also demonstrate surprising abilities to sense and respond to their environment, challenging the idea that intelligence is limited to creatures with brains. Weak fields of bioelectricity could be how cells communicate with each other and transmit information throughout the body.

What the experts say: "All intelligence is really collective intelligence, because every cognitive system is made of some kind of parts,” says Levin, who also studied the role of bioelectricity in frog development and the origin of cancer.

 body cells are able to use weak electric fields to store information. 

Comment by Dr. Krishna Kumari Challa on January 30, 2024 at 11:13am

The first observation of a material exhibiting a supersolid phase of matter

Through experimental research, a team of physicists affiliated with multiple institutions in China has observed a material in a supersolid phase of matter for the first time. In their paper published in the journal Nature, the group describes the experiments they conducted to accomplish this feat and its implications. Nature has published a Research Briefing in the same journal issue outlining the work done by the team on this effort.

A supersolid is a seemingly contradictory material—it is defined as rigid, but also has superfluidity, in which a liquid flows without friction. In the 1970s, theoretical work by Anthony Leggett suggested that such a material might be possible. But until now, no one has been able to find it in nature or synthesize it in the lab.

To create a supersolid, the researchers involved in this new study started with a compound called NBCP—it has the unique attribute of atoms arranged in triangular lattices. This means, the research team found, that if it is placed within a magnetic field, all its atoms will spin in the same direction.

But when the magnet is removed, the atoms all try to orient themselves with a spin opposite that of their neighbor—but because they are arranged in a triangle, "frustration" arises because of the limited possible orientations. This observation suggested that under the right conditions, NBCP could exist as a supersolid.

To create the right conditions, the researchers built an apparatus to measure the magnetocaloric effect as the material was exposed to a magnetic field without fear of heat leaks. This allowed them to map the entropy state, which in turn allowed them to detect the spin states of the atoms and their transitions. They compared the findings with theoretical calculations and determined that they were on the right track. They then carried out neutron diffraction measurements and compared them to theoretical calculations, and once again found agreement. Together, such measurements allowed them to conclude that they had observed a material in its supersolid state. The observation is expected to open new possibilities for studying quantum phenomena and simulating novel materials.

Junsen Xiang et al, Giant magnetocaloric effect in spin supersolid candidate Na2BaCo(PO4)2, Nature (2024). DOI: 10.1038/s41586-023-06885-w

Spin supersolid with giant magnetocaloric effect promises a new route to extreme cooling, Nature (2024). DOI: 10.1038/d41586-023-04102-2. www.nature.com/articles/d41586-023-04102-2

Comment by Dr. Krishna Kumari Challa on January 30, 2024 at 11:07am

Researchers slow down light in metasurfaces with record low loss

The speed of light can be intentionally reduced in various media. Various techniques have been developed over the years to slow down light, including electromagnetically induced transparency (EIT), Bose-Einstein condensate (BEC), photonic crystals, and stimulated Brillouin scattering (SBS).

Notably, researchers from Harvard, led by Lene Vestergaard Hau, reduced light speed to 17 m/s in an ultracold atomic gas using EIT, which sparked the interest in exploring EIT analogs in metasurfaces, a transformative platform in optics and photonics.

Despite the benefits, slow-light structures face a significant challenge: Loss, which limits storage time and interaction length. This issue is particularly severe for metasurface analogs of EIT due to scattering loss of nanoparticles and sometimes absorption loss of materials.

In a study published in Nano Letters, researchers introduced a novel strategy to realize a metasurface analog of EIT while effectively suppressing losses.

Unlike conventional metasurface analogs of EIT induced by coupling between two localized resonances supported by closely packed meta-atoms, or between localized and collective resonances, the researchers proposed a new type called "collective EIT-like resonance," which is induced by the coupling between two collective resonances—a Mie electric dipole surface lattice resonance (ED-SLR) and an in-plane or out-of-plane electric quadrupole SLR (EQ-SLR).

Using silicon metasurfaces with a 100 nm-thick nanodisk array, they demonstrated collective EIT-like resonances with a quality factor exceeding 2,750, more than five times the state-of-the-art. In practical terms, light passing through the silicon nanodisks can be slowed down by more than 10,000 times, with a reduction in loss by more than five times compared to existing methods.

The departure from the conventional belief that metasurface performance depends on how closely meta-atoms can be placed. The researchers explored the extreme regime of zero distance between meta-atoms, essentially merging them into one. Unlike conventional methods, their approach allowed the tuning of surface lattice resonances to overlap spectrally, enabling the realization of metasurface analogs of EIT.

Furthermore, the researchers demonstrated a BIC-characterized collective EIT-like resonance utilizing the transition between the in-plane EQ-SLR and the bound state in the continuum (BIC). This suggested the potential to slow down light by an arbitrarily large factor while maintaining a growing quality factor.

 Xueqian Zhao et al, Ultrahigh-Q Metasurface Transparency Band Induced by Collective–Collective Coupling, Nano Letters (2024). DOI: 10.1021/acs.nanolett.3c04174

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