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Comment by Dr. Krishna Kumari Challa on February 3, 2021 at 8:38am

An origami-inspired medical patch for sealing internal injuries

Many surgeries today are performed via minimally invasive procedures, in which a small incision is made and miniature cameras and surgical tools are threaded through the body to remove tumors and repair damaged tissues and organs. The process results in less pain and shorter recovery times compared to open surgery.

While many procedures can be performed in this way, surgeons can face challenges at an important step in the process: the sealing of internal wounds and tears.

The bioadhesives currently used in minimally invasive surgeries are available mostly as biodegradable liquids and glues that can be spread over damaged tissues. When these glues solidify, however, they can stiffen over the softer underlying surface, creating an imperfect seal. Blood and other biological fluids can also contaminate glues, preventing successful adhesion to the injured site. Glues can also wash away before an injury has fully healed, and, after application, they can also cause inflammation and scar tissue formation.

Taking inspiration from origami, MIT engineers have now designed a medical patch that can be folded around minimally invasive surgical tools and delivered through airways, intestines, and other narrow spaces, to patch up internal injuries. The patch resembles a foldable, paper-like film when dry. Once it makes contact with wet tissues or organs, it transforms into a stretchy gel, similar to a contact lens, and can stick to an injured site.

Given the limitations of current designs, the team aimed to engineer an alternative that would meet three functional requirements. It should be able to stick to the wet surface of an injured site, avoid binding to anything before reaching its destination, and once applied to an injured site resist bacterial contamination and excessive inflammation.

The team's design meets all three requirements, in the form of a three-layered patch. The middle layer is the main bioadhesive, made from a hydrogel material that is embedded with compounds called NHS esters. When in contact with a wet surface, the adhesive absorbs any surrounding water and becomes pliable and stretchy, molding to a tissue's contours. Simultaneously, the esters in the adhesive form strong covalent bonds with compounds on the tissue surface, creating a tight seal between the two materials. 

This could be used to repair a perforation from a coloscopy, or seal solid organs or blood vessels after a trauma or elective surgical intervention. Instead of having to carry out a full open surgical approach, one could go from the inside to deliver a patch to seal a wound at least temporarily and maybe even long-term.

In contrast to existing surgical adhesives, the team's new tape is designed to resist contamination when exposed to bacteria and bodily fluids. Over time, the patch can safely biodegrade away. The team has published its results in the journal Advanced Materials.

Sarah J. Wu et al. A Multifunctional Origami Patch for Minimally Invasive Tissue Sealing, Advanced Materials (2021). DOI: 10.1002/adma.202007667

https://phys.org/news/2021-02-origami-inspired-medical-patch-intern...

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 11:59am

A new treatment to help people with a spinal cord injury

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 11:59am

A call for a global ban on lead paint

Once lead paint is on a wall, it becomes an expensive problem to fix. In impoverished settings, be they neighborhoods in Philadelphia or developing nations globally, remediation can be prohibitively costly.

Branches and treetops can reduce greenhouse gas emission from heavy...

New research from University of Gävle shows that forest residues can generate large amounts of biofuel, and, in the long run, reduce greenhouse gas emission by 88-94% from heavy transport on Swedish roads.

Water disinfection with ozone

While chlorine and ultraviolet light are the standard means of disinfecting water, ozone is equally effective in killing germs. To date, ozone has only been used as an oxidation agent for treating water in large plants. Now, however, a project consortium from Schleswig-Holstein is developing a miniaturized ozone generator for use in smaller applications such as water dispensers or small domestic appliances. The Fraunhofer Institute for Silicon Technology ISIT has provided the sensor chip and electrode substrates for the electrolysis cell.

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 10:40am

Virtual conference CO2 emissions quantified in new study

The virtual conferencing that has replaced large, in-person gatherings in the age of COVID-19 represents a drastic reduction in carbon emissions, but those online meetings still come with their own environmental costs, new research from the University of Michigan shows.

The research offers a framework for analyzing and tallying the carbon emissions of an online conference based on factors that include everything from energy used by servers and monitors to the resources used to manufacture and distribute the computers involved.

Individuals could skip features like gallery view, disable HD video and repair instead of replace computers to extend their useful lifetimes.

Grant Faber. A framework to estimate emissions from virtual conferences, International Journal of Environmental Studies (2021). DOI: 10.1080/00207233.2020.1864190

https://phys.org/news/2021-02-virtual-conference-co2-emissions-quan...

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 10:34am

Lactobacillus manipulates bile acids to create favorable gut environment

New research  reveals that probiotic Lactobacillus bacteria use enzymes situationally to manipulate bile acids and promote their own survival in the gut. These findings further elucidate the complicated relationship between bile acids and gut bacteria and could eventually enable researchers to design lactobacilli with therapeutic properties, thereby engineering a healthier human gut environment.

Bile acids are key players in digestion and overall gut health. Produced in the liver and released after we eat, these acids not only break down cholesterol and help regulate fat absorption, they also have a huge impact on what types of bacteria colonize the gut.

As bile acids move through the gut, they are initially chemically modified through the addition of an amino acid (frequently glycine or taurine), creating a complex "conjugated" bile acid pool. Some gut bacteria have enzymes, called bile salt hydrolases (BSHs), which can cleave or "deconjugate" these amino acids from the bile acids, allowing other bacteria to further transform the bile acids as they continue through the colon. These transformations affect the bile acids' toxicity, which in turn affects the ability of different bacteria to survive in the gut.

The assumed relationship was that probiotic bacteria like Lactobacillus have BSHs that just deconjugate the bile acid, rendering it less toxic and allowing the bacteria to survive.

The interplay between bile and bacteria has a huge impact on their ability to live, thrive or die in a very competitive environment.

 Matthew H. Foley el al., "Lactobacillus bile salt hydrolase substrate specificity governs bacterial fitness and host colonization," PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2017709118

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It was found that bile acid toxicity was not merely dependent upon whether the bile acid was conjugated or deconjugated by a BSH; rather, the relationships were dependent upon the type of bile acid, the bacteria being acted upon, and which BSH was present.

https://phys.org/news/2021-02-lactobacillus-bile-acids-favorable-gu...

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 10:29am

Marine organisms use previously undiscovered receptors to detect, respond to light

Just as plants and animals on land are keenly attuned to the hours of sunlight in the day, life in the oceans follows the rhythms of the day, the seasons and even the moon. A new study finds the biological light switches that make this possible.

Single-celled organisms in the open ocean use a diverse array of genetic tools to detect light, even in tiny amounts, and respond.

If you look in the ocean environment, all these different organisms have this day-night cycle. They are very in tune with each other, even as they get moved around. How do they know when it's day? How do they know when it's night?

By analyzing RNA filtered out of seawater samples collected throughout the day and night, the study identifies four main groups of photoreceptors, many of them new. This genetic activity uses light to trigger changes in the metabolism, growth, cell division, movements and death of marine organisms.

The discovery of these new genetic "light switches" could also aid in the field of optogenetics, in which a cell's function can be controlled with light exposure. Today's optogenetic tools are engineered by humans, but versions from nature might be more sensitive or better detect light of particular wavelengths, the researchers think.

Sacha N. Coesel el al., "Diel transcriptional oscillations of light-sensitive regulatory elements in open-ocean eukaryotic plankton communities," PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2011038118

https://phys.org/news/2021-02-marine-previously-undiscovered-recept...

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 10:24am

Part 2

investigated whether sidewinders' skin might also play a role in their unique movement style.

They focused on three species of sidewinders, all of them vipers, in residence at zoos: The sidewinder rattlesnake (Crotalus cerastes), found in the deserts of the Southwestern United States and northern Mexico; and the Saharan horned viper (Cerastes cerastes) and the Saharan sand viper (Cerastes vipera), both from the deserts of north Africa.

Skins shed from the sidewinders were collected and scanned with atomic force microscopy, a technique that provides resolution at the atomic level, on the order of fractions of a nanometer. For comparison, they also scanned snake skins shed from non-sidewinders.

As expected, the microscopy revealed tiny, head-to-tail pointing spikes on the skin of the non-sidewinders. Previous research had identified these micro spikes on a variety of other slithering snakes.

The current study, however, found that the skin of sidewinders is different. The two African sidewinders had micro pits on their bellies and no spikes. The skin of the sidewinder rattlesnake was also studded with tiny pits, along with a few, much smaller, spikes—although far fewer spikes than those of the slithering snakes.

The researchers created a mathematical model to test how these different structures affect frictional interactions with a surface. The model showed that head-to-tail pointing spikes enhance the speed and distance of forward undulation but are detrimental to sidewinding.

The model also showed that the uniform, non-directional structure of the round pits enhanced sidewinding, but was not as efficient as spikes for forward undulation.

The research provides snapshots at different points in time of convergent evolution—when different species independently evolve similar traits as a result of having to adapt to similar environments.

Jennifer M. Rieser el al., "Functional consequences of convergently evolved microscopic skin features on snake locomotion," PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2018264118

https://phys.org/news/2021-02-physics-snakeskin-sidewinding.html?ut...

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 10:23am

Physics of snakeskin sheds light on sidewinding

Most snakes get from one place  to another by bending their bodies into S-shapes and slithering forward headfirst. A few species, however—found in the deserts of North America, Africa and the Middle East—have an odder way of getting around. Known as "sidewinders," these snakes lead with their mid-sections instead of their heads, slinking sideways across loose sand.

Scientists took a microscopic look at the skin of sidewinders to see if it plays a role in their unique method of movement. They discovered that sidewinders' bellies are studded with tiny pits and have few, if any, of the tiny spikes found on the bellies of other snakes.

The specialized locomotion of sidewinders evolved independently in different species in different parts of the world, suggesting that sidewinding is a good solution to a problem. Understanding how and why this example of convergent evolution works may allow us to adapt it for our own needs, such as building robots that can move in challenging environments.

This research bring together the physics of soft matter—flowable materials like sand—and organismal biology. The study shows how animals' surfaces interact with the flowable materials in their environments to get around. Insights from the research may lead to improvements in human technology.

Most snakes tend to keep their bellies largely in contact with the ground as they slide forward, bending their bodies from their heads to their tails. A sidewinder, however, lifts its midsection off the ground, shifting it in a sideways direction.

Previous studies have hypothesized that sidewinding may allow a snake to move better on sandy slopes.

Part 1

Comment by Dr. Krishna Kumari Challa on February 1, 2021 at 10:55am

Using science to explain the mysterious Dyatlov Pass Incident

Comment by Dr. Krishna Kumari Challa on February 1, 2021 at 10:04am

Mouse study: Gabapentin prevents harmful structural changes in spin...

Research led by The Ohio State University Wexner Medical Center and College of Medicine found that the widely prescribed pain-relief drug gabapentin can prevent harmful structural changes in the injured spinal cords of mice, and also block cardiovascular changes and immune suppression caused by spinal cord injury.

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Study provides insight into how the brain may have evolved

Researchers from The University of Western Australia have uncovered evidence of an important genetic step in the evolution of the brain. The finding highlights how genetic events that took place in our fish-like ancestors play crucial roles in human brain biology today.

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How vitamins, steroids and potential antivirals might affect SARS-C...

Evidence is emerging that vitamin D—and possibly vitamins K and A—might help combat COVID-19. A new study from the University of Bristol published in the journal of the German Chemical Society Angewandte Chemie has shown how they—and other antiviral drugs—might work. The research indicates that these dietary supplements and compounds could bind to the viral spike protein and so might reduce SARS-CoV-2 infectivity. In contrast, cholesterol may increase infectivity, which could explain why having high cholesterol is considered a risk factor for serious disease.

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