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Comment by Dr. Krishna Kumari Challa on October 16, 2020 at 9:11am

A hydrogel that could help repair damaged nerves
Injuries to peripheral nerves –– tissues that transmit bioelectrical signals from the brain to the rest of the body –– often result in chronic pain, neurologic disorders, paralysis or disability. Now, researchers have developed a stretchable conductive hydrogel that could someday be used to repair these types of nerves when there’s damage.

Injuries in which a peripheral nerve has been completely severed, such as a deep cut from an accident, are difficult to treat. A common strategy, called autologous nerve transplantation, involves removing a section of peripheral nerve from elsewhere in the body and sewing it onto the ends of the severed one. However, the surgery does not always restore function, and multiple follow-up surgeries are sometimes needed. Artificial nerve grafts, in combination with supporting cells, have also been used, but it often takes a long time for nerves to fully recover.

Now researchers prepared a tough but stretchable conductive hydrogel containing polyaniline and polyacrylamide. The crosslinked polymer had a 3D microporous network that, once implanted, allowed nerve cells to enter and adhere, helping restore lost tissue. They showed that the material could conduct bioelectrical signals through a damaged sciatic nerve removed from a toad. Then, they implanted the hydrogel into rats with sciatic nerve injuries. Two weeks later, the rats’ nerves recovered their bioelectrical properties, and their walking improved compared with untreated rats. Because the electricity-conducting properties of the material improve with irradiation by near-infrared light, which can penetrate tissues, it could be possible to further enhance nerve conduction and recovery in this way, the researchers say.

https://www.acs.org/content/acs/en/pressroom/newsreleases/2020/octo...

https://researchnews.cc/news/3043/A-hydrogel-that-could-help-repair...

Comment by Dr. Krishna Kumari Challa on October 16, 2020 at 8:51am

The Lancet: Herd immunity approaches to COVID-19 control are a 'dangerous fallacy', say authors of open letter

A group of 80 researchers warn that a so-called herd immunity approach to managing COVID-19 by allowing immunity to develop in low-risk populations while protecting the most vulnerable is "a dangerous fallacy unsupported by the scientific evidence".

The open letter, referred to by its authors as the John Snow Memorandum, is published today by The Lancet. It is signed by 80 international researchers (as of publication) with expertise spanning public health, epidemiology, medicine, paediatrics, sociology, virology, infectious disease, health systems, psychology, psychiatry, health policy, and mathematical modelling [1]. The letter will also be launched during the 16th World Congress on Public Health programme 2020.

https://www.eurekalert.org/pub_releases/2020-10/tl-pss101420.php

Comment by Dr. Krishna Kumari Challa on October 16, 2020 at 6:21am

Scientists discovered hidden colours created by a new mechanism

Scientists have stumbled across an unusual way to observe colour that had previously gone unnoticed.

To create the effect, researchers attached a very thin film of one material to another, larger sample. The electric field (an invisible force created by the attraction and repulsion of electrical charges) is very strong where the two materials are connected.

When combined with 'optical interference' (the interaction of different waves of light), a scattering process occurs from the surface of the material, creating bright colors when viewed under different lighting conditions.

Most materials in the world around us appear a certain color because they only absorb part of solar spectrum. For example, leaves on a tree look green to us because they absorb red and blue light.

However, some objects, animals and materials create color a different way, because of the properties they contain. These are known as structural colors.

Structural colors are usually created by diffraction, which happens when rays of light interfere with each other as they reflect off surfaces. Rainbows and colorful oil slicks on top of water are examples of structural color, and the effect is also responsible for the amazing vivid hues of peacock feathers and butterfly wings.

While those phenomena are well established, an unexpected new mechanism for creating similar effects has been uncovered.

The effect is an example of structural color forming because of frequency-selective scattering of light, in which the strength of the electric field and the type of material used is a key factor.

Scientists using  a light microscope to observe gold nanoparticles  unexpectedly noticed that the entire sample was creating a vivid colour visible to the naked eye from all directions.

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To understand it properly, they created thin films which could scatter light and at the same time create diffraction or interference. The system was made using silicon nitride coatings on larger metallic aluminum samples.

Different colors were visible by changing the lighting conditions. Under normal light, the samples looked like a mirror, reflecting back almost all visible light. But turning the overhead lights off and using only one beam of light to illuminate the sample produces vivid, iridescent colors.

Explaining how to easily observe this phenomenon, Eser said: "If you use a flashlight, while in a dark room, to illuminate the sample, the reflected light beam travels away from you to the other side of the room.

"The reflected light never reaches your eyes, only the scattered light can reach your eyes. Whereas when the room light is on, light comes from everywhere on to the sample and therefore you will always see reflected light traveling into your eyes.

"The effect is a previously completely unrecognized curiosity that results in us seeing color. It's fundamentally something different."

 Eser Metin Akinoglu et al. Concealed Structural Colors Uncovered by Light Scattering, Advanced Optical Materials (2020). DOI: 10.1002/adom.202001307

https://phys.org/news/2020-10-dont-hidden-colours-coincidence.html?...

Comment by Dr. Krishna Kumari Challa on October 16, 2020 at 6:08am

Symptoms all in your head—or in your gut? Maybe a little of both.

Anyone who has ever experienced "butterflies in the stomach" before giving a big presentation won't be surprised to learn there is an actual physical connection between their gut and their brain. Neuroscientists and medical professionals call this the "gut-brain-axis" (GBA). A better understanding of the GBA could lead to treatments and cures for neurological mood disorders like depression and anxiety, as well as for a range of chronic auto-immune inflammatory diseases like irritable bowel syndrome (IBS) and rheumatoid arthritis (RA).

Scientists suspect the chemical neurotransmitter serotonin is the biomarker for a range of GBA disorders. Serotonin spurs the nervous system into action via the vagus nerve, the physical connector between the brain and the colon. Generated deep within the lining of the gut, serotonin ultimately influences everything from mood and emotions to sleep, digestion and the secretion of hormones. Its production is in some way affected by the bacterial "microbiome" present in this environment. Researchers hope that creating tools to analyze serotonin's production and dysfunction in the gut microbiome will help unlock the mysteries of GBA-related disorders.

Three new published papers detail the progress in detecting serotonin, assessing its neurological effects, and sensing minute changes to the gut epithelium.

 Pradeep Ramiah Rajasekaran et al, 3D-Printed electrochemical sensor-integrated transwell systems, Microsystems & Nanoengineering (2020). DOI: 10.1038/s41378-020-00208-z

Ashley A. Chapin et al. Electrochemical measurement of serotonin by Au-CNT electrodes fabricated on microporous cell culture membranes, Microsystems & Nanoengineering (2020). DOI: 10.1038/s41378-020-00184-4 A.

A. Chapin, J. Han, T. -W. Ho, J. Herberholz and R. Ghodssi, "A Hybrid Biomonitoring System for Gut-Neuron Communication," in Journal of Microelectromechanical Systems, vol. 29, no. 5, pp. 727-733, Oct. 2020, DOI: 10.1109/JMEMS.2020.3000392.

Pradeep Ramiah Rajasekaran et al. 3D-Printed electrochemical sensor-integrated transwell systems, Microsystems & Nanoengineering (2020). DOI: 10.1038/s41378-020-00208-z

https://phys.org/news/2020-10-symptoms-heador-gut.html?utm_source=n...

Comment by Dr. Krishna Kumari Challa on October 16, 2020 at 5:44am

When feeling the pinch, nuclei instigate cells to escape crowded spaces

The threat of serious deformation triggers a rapid escape reflex that enables cells to move away and squeeze out from tight spaces or crowded tissues.

In a new study  researchers reveal that squeezing a cell to the point where its nucleus starts to stretch triggers the activation of motor proteins which in turn transform the cell's cytoskeleton so that it can flee a packed environment.

Each cell has a nucleus, and each nucleus has a membrane that separates the chromosomes from the rest of the cell. At a rest state, the nuclear membrane is saggy, akin to a loose shopping bag. Now researchers have found that when the nuclear membrane  is squeezed, the wrinkles on its surface iron themselves out, instigating a cascade of events that transform the cytoskeleton and eventually aid the cell in escaping its crowded environment.

The nucleus measures shape changes for cellular proprioception to control dynamic cell behavior, Science (2020). DOI: 10.1126/science.aba2644

Study finds how body cells move within a tissue

https://phys.org/news/2020-10-nuclei-instigate-cells-crowded-spaces...

Comment by Dr. Krishna Kumari Challa on October 15, 2020 at 1:09pm

Science Pinpoints Global Metal Deposit Locations

Miners can find new deposits with less effort

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Decoy Cells Trick SARS-CoV-2, Reduce Cytokines In Vitro

Genetically engineered cells that overproduce ACE2, the receptor the novel coronavirus uses to enter cells, neutralize infection in vitro and mop up inflammatory cytokines in mice.

https://www.the-scientist.com/news-opinion/decoy-cells-trick-sars-c...

Comment by Dr. Krishna Kumari Challa on October 15, 2020 at 1:05pm

Electric and Magnetic Field Treatments Lower Mouse Blood Sugar

**The effects seem to be mediated by a reactive oxygen species in the animals’ livers.

https://www.the-scientist.com/news-opinion/electric-and-magnetic-fi...

Comment by Dr. Krishna Kumari Challa on October 15, 2020 at 7:55am

New areas at risk of drinking water arsenic exposure in India

An international team involving researchers based in Manchester (UK), Patna (India) and Zurich (Switzerland) has found new areas of arsenic contamination in drinking water in India. Their country-specific, country-wide model for well water arsenic in India has recently been published in the International Journal for Environmental Research and Public Health.

Their model confirms the known high probability of finding hazardous high arsenic well waters in northern India in the river basins of the Ganges and Brahmaputra. What is new and particularly concerning, is that the model also finds an elevated probability of high arsenic well waters in other Indian areas, where previously arsenic hazard was generally not considered to be a major concern—so much so that in many of these areas well water arsenic is not routinely checked.

These areas include parts of south-west and central India and are mostly areas underlain by sediments and sedimentary rocks.

The study suggests follow up to help better define specific areas in which action is required to reduce adverse public health outcomes from drinking high arsenic well waters. The study also highlights the importance of systematic testing of hazards, not just in known high hazard areas, but also through random sampling of all wells used for drinking water.

Joel Podgorski et al. Groundwater Arsenic Distribution in India by Machine Learning Geospatial Modeling, International Journal of Environmental Research and Public Health (2020). DOI: 10.3390/ijerph17197119

https://phys.org/news/2020-10-areas-arsenic-exposure-india.html?utm...

Comment by Dr. Krishna Kumari Challa on October 15, 2020 at 7:40am

The Great Barrier Reef has lost half its corals

A new study of the Great Barrier Reef shows populations of its small, medium and large corals have all declined in the past three decades. Scientists  found the number of small, medium and large corals on the Great Barrier Reef has declined by more than 50 percent since the 1990s.

The decline occurred in both shallow and deeper water, and across virtually all species—but especially in branching and table-shaped corals. These were the worst affected by record-breaking temperatures that triggered mass bleaching in 2016 and 2017.

Climate change is driving an increase in the frequency of reef disturbances such as marine heatwaves. 'There is no time to lose—we must sharply decrease greenhouse gas emissions ASAP if we want to protect them from more degradation and total loss', the researchers conclude.

Andreas Dietzel et al, Long-term shifts in the colony size structure of coral populations along the Great Barrier Reef, Proceedings of the Royal Society B: Biological Sciences (2020). DOI: 10.1098/rspb.2020.1432

https://phys.org/news/2020-10-great-barrier-reef-lost-corals.html?u...

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Scientists shed new light on viruses' role in coral bleaching

Scientists  have shown that viral infection is involved in coral bleaching—the breakdown of the symbiotic relationship between corals and the algae they rely on for energy.

After analyzing the viral metagenomes they found that bleached corals had a higher abundance of eukaryotic viral sequences, and non-bleached corals had a higher abundance of bacteriophage sequences. This gave the researchers the first quantitative evidence of a shift in viral assemblages between coral bleaching states.
Bacteriophage viruses infect and replicate within bacteria. Eukaryotic viruses infect non-bacterial organisms like animals.
In addition to having a greater presence of eukaryotic viruses in general, bleached corals displayed an abundance of what are called giant viruses. Known scientifically as nucleocytoplasmic large DNA viruses, or NCLDV, they are complex, double-stranded DNA viruses that can be parasitic to organisms ranging from the single-celled to large animals, including humans.
Giant viruses have been implicated in coral bleaching. Now scientists were able to generate the first draft genome of a giant virus that might be a factor in bleaching.

Adriana Messyasz et al, Coral Bleaching Phenotypes Associated With Differential Abundances of Nucleocytoplasmic Large DNA Viruses, Frontiers in Marine Science (2020). DOI: 10.3389/fmars.2020.555474

https://phys.org/news/2020-10-scientists-viruses-role-coral.html?ut...

Comment by Dr. Krishna Kumari Challa on October 15, 2020 at 7:34am

Scientists home in on the mechanism that protects cells from premature aging

Molecules that accumulate at the tip of chromosomes are known to play a key role in preventing damage to our DNA. Now, researchers  have unraveled how these molecules home in on specific sections of chromosomes—a finding that could help to better understand the processes that regulate cell survival in aging and cancer.

Much like the aglet of a shoelace prevents the end of the lace from fraying, stretches of DNA called telomeres form protective caps at the ends of chromosomes. But as cells divide, telomeres become shorter, making the protective cap less effective. Once telomeres get too short, the cell stops dividing. Telomere shortening and malfunction have been linked to cell aging and age-related diseases, including cancer.

Scientists have known that RNA species called TERRA help to regulate the length and function of telomeres. Discovered in 2007  TERRA belongs to a class of molecules called noncoding RNAs, which are not translated into proteins but function as structural components of chromosomes. TERRA accumulates at chromosome ends, signaling that telomeres should be elongated or repaired.

However, it was unclear how TERRA got to the tip of chromosomes and remained there. "The telomere  makes up only a tiny bit of the total chromosomal DNA, so the question is 'how does this RNA find its home. By visualizing TERRA molecules under a microscope, the researchers found that a short stretch of the RNA is crucial to bring it to telomeres. Further experiments showed that once TERRA reaches the tip of chromosomes, several proteins regulate its association with telomeres. Among these proteins, one called RAD51 plays a particularly important role. RAD51 is a well-known enzyme that is involved in the repair of broken DNA molecules. The protein also seems to help TERRA stick to telomeric DNA to form a so-called "RNA-DNA hybrid molecule". Scientists thought this type of reaction, which leads to the formation of a three-stranded nucleic acid structure, mainly happened during DNA repair. The new study shows that it can also happen at chromosome ends when TERRA binds to telomeres. The researchers also found that short telomeres recruit TERRA much more efficiently than long telomeres. Although the mechanism behind this phenomenon is unclear, the researchers hypothesize that when telomeres get too short, either due to DNA damage or because the cell has divided too many times, they recruit TERRA molecules. This recruitment is mediated by RAD51, which also promotes the elongation and repair of telomeres. "TERRA and RAD51 help to prevent accidental loss or shortening of telomeres. That's an important function."

Given the role of telomeres in health and disease, it will be important to see how the newly discovered mechanism—which was deduced from observations in living cells and reproduced in test tubes—is regulated in the very complex cellular environment.

RAD51-dependent recruitment of TERRA long noncoding RNA to telomeres through R-loops, Nature (2020). DOI: 10.1038/s41586-020-2815-6

https://phys.org/news/2020-10-scientists-home-mechanism-cells-prema...

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