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Comment by Dr. Krishna Kumari Challa on April 30, 2021 at 8:46am

New law of physics helps humans and robots grasp the friction of touch

Although robotic devices are used in everything from assembly lines to medicine, engineers have a hard time accounting for the friction that occurs when those robots grip objects—particularly in wet environments. Researchers have now discovered a new law of physics that accounts for this type of friction, which should advance a wide range of robotic technologies.

At issue is something called elastohydrodynamic lubrication (EHL) friction, which is the friction that occurs when two solid surfaces come into contact with a thin layer of fluid between them. This would include the friction that occurs when you rub your fingertips together, with the fluid being the thin layer of naturally occurring oil on your skin. But it could also apply to a robotic claw lifting an object that has been coated with oil, or to a surgical device that is being used inside the human body.

One reason friction is important is because it helps us hold things without dropping them.

Understanding friction is intuitive for humans—even when we're handling soapy dishes. But it is extremely difficult to account for EHL friction when developing materials that controls grasping capabilities in robots.

To develop materials that help control EHL friction, engineers would need a framework that can be applied uniformly to a wide variety of patterns, materials and dynamic operating conditions. And that is exactly what the researchers have discovered.

In this context, surface patterns could be anything from the slightly raised surfaces on the tips of our fingers to grooves in the surface of a robotic tool.

The new physical principle makes use of four equations to account for all of the physical forces at play in understanding EHL friction. In the paper, the research team demonstrated the law in three systems: human fingers; a bio-inspired robotic fingertip; and a tool called a tribo-rheometer, which is used to measure frictional forces. 

It has obvious applications in the realm of telesurgery, in which surgeons remotely control robotic devices to perform surgical procedures.

Elastohydrodynamic friction of robotic and human fingers on soft micropatterned substrates, Nature Materials (2021). DOI: 10.1038/s41563-021-00990-9

https://phys.org/news/2021-04-law-physics-humans-robots-grasp.html?...

Comment by Dr. Krishna Kumari Challa on April 30, 2021 at 8:23am

4 women whose work won the Nobel Prize for their male colleagues

Throughout history, female scientists have made groundbreaking discoveries that have contributed to the betterment of humankind. To celebrate Women’s History Month, this Special Feature looks at some of the most influential female scientists who never received a Nobel Prize for their work. Instead, the Prize landed in the hands of their male colleagues.

Physicist Lise Meitner (1878–1968)

Physicist Chien-Shiung Wu (1912–1997)

Chemist Rosalind Franklin (1920–1958)

Microbiologist Esther Lederberg (1922–2006)

https://www.medicalnewstoday.com/articles/4-women-whose-work-won-th...

https://www.medicalnewstoday.com/articles/its-time-to-change-the-na...

Comment by Dr. Krishna Kumari Challa on April 29, 2021 at 1:21pm

Earth has been knocked off its axis over the last 25 years, changing the locations of the north and south poles

• Earth's axis - the invisible line around which it spins - is bookended by the north and south poles.
• The axis, and thus the poles too, shift depending on how weight is distributed across Earth's surface.
• Melting glaciers have changed that distribution enough to knock Earth off its axis, research shows.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL092114

https://www.businessinsider.in/science/news/earth-has-been-knocked-...

Comment by Dr. Krishna Kumari Challa on April 29, 2021 at 9:08am

One dose of COVID vaccine cuts household spread by up to 50%:  study

One dose of the Pfizer or AstraZeneca vaccines reduces the chances of someone infected with coronavirus from spreading it to other household members by up to 50 percent, according to a  study published Wednesday.

The Public Health England (PHE) research found that those who became infected three weeks after receiving their first jab were between 38 and 49 percent less likely to pass the virus on to their household contacts than those who were unvaccinated.

We already know vaccines save lives and this study is the most comprehensive real-world data showing they also cut transmission of this deadly virus. It further reinforces that vaccines are the best way out of this pandemic as they protect you and they may prevent you from unknowingly infecting someone in your household.

Studies have already shown that being vaccinated reduces the risk of a person developing symptomatic infection in the first place by up to 65 percent, four weeks after one dose.

https://medicalxpress.com/news/2021-04-dose-covid-vaccine-household...

Comment by Dr. Krishna Kumari Challa on April 28, 2021 at 12:07pm

Farming without disturbing soil could cut agriculture’s climate impact by 30% – new research

agriculture accounts for a staggering 26% of all greenhouse gas emissions. Tractors running on diesel release carbon dioxide (CO₂) from their exhausts. Fertilisers spread on fields produce nitrous oxide. And cattle generate methane from microbes in their guts.

Even tilling the soil – breaking it up with ploughs and other machinery – exposes carbon buried in the soil to oxygen in the air, allowing microbes to convert it to CO₂. Farmers usually do this before sowing crops, but what if they could avoid this step?

In newly published research from farms across the UK, we discovered that an alternative approach called no-till farming, which does not disturb soils and instead involves placing seeds in drilled holes in the earth, could slash greenhouse gas emissions from crop production by nearly a third and increase how much carbon soils can store.

https://theconversation.com/farming-without-disturbing-soil-could-c...

Comment by Dr. Krishna Kumari Challa on April 28, 2021 at 11:38am

Five new insights in the fight against COVID-19

Researchers announce new findings on treatments, health impacts and repercussions for science education

Scientists from around the world are gathering to share the latest research at the forefront of biology during the Experimental Biology (EB) 2021 meeting. Many sessions focus on the year's most pressing priorities in bioscience: COVID-19 and the virus that causes it, SARS-CoV-2. 

Five new insights in the fight against COVID-19

https://www.eurekalert.org/pub_releases/2021-04/eb-fni041621.php

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Comment by Dr. Krishna Kumari Challa on April 28, 2021 at 11:13am

Scientists design 'nanotraps' to catch, clear coronavirus

Researchers have designed a completely novel potential treatment for COVID-19: nanoparticles that capture SARS-CoV-2 viruses within the body and then use the body's own immune system to destroy it.

These "Nanotraps" attract the virus by mimicking the target cells the virus infects. When the virus binds to the Nanotraps, the traps then sequester the virus from other cells and target it for destruction by the immune system.

In theory, these Nanotraps could also be used on variants of the virus, leading to a potential new way to inhibit the virus going forward. Though the therapy remains in early stages of testing, the researchers envision it could be administered via a nasal spray as a treatment for COVID-19.

The results were published April 19 in the journal Matter.

Min Chen et al, Nanotraps for the containment and clearance of SARS-CoV-2, Matter (2021). DOI: 10.1016/j.matt.2021.04.005

https://phys.org/news/2021-04-scientists-nanotraps-coronavirus.html...

Comment by Dr. Krishna Kumari Challa on April 28, 2021 at 11:10am

Researchers discover two-dimensional material using high-pressure technology

An international team of researchers has succeeded for the first time in discovering a previously unknown two-dimensional material by using modern high-pressure technology. The new material, beryllonitrene, consists of regularly arranged nitrogen and beryllium atoms. It has an unusual electronic lattice structure that shows great potential for applications in quantum technology. Its synthesis required a compression pressure that is about one million times higher than the pressure of the Earth's atmosphere. The scientists have presented their discovery in the journal Physical Review Letters.

Researchers  have now produced novel compunds composed of nitrogen and beryllium atoms. These are beryllium polynitrides, some of which conform to the monoclinic, others to the triclinic crystal system. The triclinic beryllium polynitrides exhibit one unusual characteristic when the pressure  drops. They take on a crystal structure made up of layers. Each layer contains zigzag nitrogen chains connected by beryllium atoms. It can therefore be described as a planar structure consisting of BeN₄ pentagons and Be₂N₄ hexagons. Thus, each layer represents a two-dimensional material, beryllonitrene.

Maxim Bykov et al. High-Pressure Synthesis of Dirac Materials: Layered van der Waals Bonded BeN4 Polymorph, Physical Review Letters (2021). DOI: 10.1103/PhysRevLett.126.175501

https://phys.org/news/2021-04-two-dimensional-material-high-pressur...

Comment by Dr. Krishna Kumari Challa on April 28, 2021 at 10:24am

Benefits of AstraZeneca COVID-19 vaccine outweigh its risks, modeling study suggests

The AstraZeneca COVID-19 vaccine is suspected of being linked to a small number of deep vein thrombosis (DVT) cases, which recently emerged within Europe as millions of people received vaccinations. This led several countries to suspend AstraZeneca injections and investigate the causal links to DVT.

Researchers within Europe teamed up to explore a hypothesis that pausing AstraZeneca vaccinations, even for a short duration, could cause additional deaths from the faster spread of COVID-19 within a population of susceptible individuals.

In Chaos, researchers report using an epidemiological susceptible-exposed-infected-recovered (SEIR)model and statistical analysis of publicly available data to estimate excess deaths resulting from suspending AstraZeneca vaccinations and those potentially linked to DVT-adverse events in France and Italy.

They concluded the benefits of deploying the AstraZeneca vaccine greatly outweigh its associated risks, and relative benefits are wider in situations where the reproduction number is larger.

The work shows suspending AstraZeneca vaccinations in France and Italy for three days without replacing it with another vaccine led to about 260 and 130 additional deaths, respectively.

"Interrupting vaccination policies can greatly spread SARS-CoV-2 and enhance mortality from COVID-19 disease: The AstraZeneca case for France and Italy" Chaos, aip.scitation.org/doi/10.1063/5.0050887

https://phys.org/news/2021-04-benefits-astrazeneca-covid-vaccine-ou...

Comment by Dr. Krishna Kumari Challa on April 28, 2021 at 9:47am

Skin and bones repaired by bioprinting during surgery

Fixing traumatic injuries to the skin and bones of the face and skull is difficult because of the many layers of different types of tissues involved, but now, researchers have repaired such defects in a rat model using bioprinting during surgery, and their work may lead to faster and better methods of healing skin and bones.

Currently, fixing a hole in the skull involving both bone and soft tissue requires using bone from another part of the patient's body or a cadaver. The bone must be covered by soft tissue with blood flow, also harvested from somewhere else, or the bone will die. Then surgeons need to repair the soft tissue and skin.

The researchers attacked the problem of bone replacement first, beginning in the laboratory and moving to an animal model. They needed something that was printable and nontoxic and could repair a 5-millimeter hole in the skull. The "hard tissue ink" consisted of collagen, chitosan, nano-hydroxyapatite and other compounds and mesenchymal stem cells—multipotent cells found in bone marrow that create bone, cartilage and bone marrow fat.

The hard tissue ink extrudes at room temperature but heats up to body temperature when applied. This creates physical cross-linkage of the collagen and other portions of the ink without any chemical changes or the necessity of a crosslinker additive.

The researchers used droplet printing to create the soft tissue with thinner layers than the bone. They used collagen and fibrinogen in alternating layers with crosslinking and growth enhancing compounds. Each layer of skin including the epidermis and dermis differs, so the bioprinted soft tissue layers differed in composition.

Experiments repairing 6 mm holes in full thickness skin proved successful. Once the team understood skin and bone separately, they moved on to repairing both during the same surgical procedure.

After careful imaging to determine the geometry of the defect, the researchers laid down the bone layer. They then deposited a barrier layer mimicking the periosteum, a heavily vascularized tissue layer that surrounds the bone on the skull.

Kazim K. Moncal et al, Intra‐Operative Bioprinting of Hard, Soft, and Hard/Soft Composite Tissues for Craniomaxillofacial Reconstruction, Advanced Functional Materials (2021). DOI: 10.1002/adfm.202010858

https://medicalxpress.com/news/2021-04-skin-bones-bioprinting-surge...

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