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Comment by Dr. Krishna Kumari Challa on August 19, 2022 at 9:06am

Turning to the laws of physics to study how cells move

Scientists have long been concerned with trying to understand how cells move, for example in pursuit of new ways to control the spread of cancer. The field of biology continues to illuminate the infinitely complex processes by which collections of cells communicate, adapt, and organize along biochemical pathways.

Turning to the laws of physics, researchers have taken a fresh look at how cells move, revealing similarities between the behaviour of cell tissue and the simplest water droplets. They have taken a different perspective on how cell motion is determined by the properties of the tissues they're in rather than how they act individually.

Published in Physical Review Letters, the researchers’ initial experiments used mechanical techniques to measure the surface tension of a simple "ball" of cell tissue to reveal similarities with the thermo-dynamic properties of water droplets, but with noticeable differences.

With a water droplet the surface tension is constant and doesn't change with droplet size.

However, the scientists found that in the case of a "droplet" of cancer cells surface tension was size dependent—the smaller the tissue the higher the surface tension, and the higher the pressure within the tissue.

Next, they applied a surface tension gradient to show that cells within the tissue moved rapidly and collectively, much like the way the surface of water moves when detergent is added. Their findings were published in Physical Review Fluids.

This so called "Marangoni" effect occurs when the forces at the surface of a tissue drive the motion of cells inside.

To complete the puzzle, the scientists allowed the tissue to adhere to a surface, mimicking the way a tumor grows and spreads. Cells emerged from the ball of tissue like water droplets "wetting" a receptive—or hydrophilic—surface. In some conditions, the wetting increased the internal pressure of the tissue, helping to push cells out.

Published today in Physical Review X, these findings cast new light on the degree to which cells "migrate" or whether pressure from surface tension promotes cell movement.

This new work shows that the bulk properties of tissue, including the surface tension and pressure, matter when it comes to the ability of cells to migrate out of a model tumor.

M. S. Yousafzai et al, Active Regulation of Pressure and Volume Defines an Energetic Constraint on the Size of Cell Aggregates, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.128.048103

Vikrant Yadav et al, Gradients in solid surface tension drive Marangoni-like motions in cell aggregates, Physical Review Fluids (2022). DOI: 10.1103/PhysRevFluids.7.L031101

Muhammad Sulaiman Yousafzai et al, Cell-Matrix Elastocapillary Interactions Drive Pressure-Based Wetting of Cell Aggregates, Physical Review X (2022). DOI: 10.1103/PhysRevX.12.031027

Comment by Dr. Krishna Kumari Challa on August 19, 2022 at 8:57am

Swarms of microrobots could be solution to unblocking medical devices in body

Swarms of microrobots injected into the human body could unblock internal medical devices and avoid the need for further surgery, according to new research .

The study is the first-time scientists have developed magnetic microrobotics to remove deposits in shunts—common internal medical devices used to treat a variety of conditions by draining excess fluid from organs.

Shunts are prone to malfunctioning, often caused by blockages due to a build-up of sediment. The sediment not only narrows and obstructs liquid passing through the shunt, but it also affects the shunt's flexibility. This leads to patients needing repeated, invasive surgeries throughout their lives either to replace the shunt or use a catheter to remove the blockage.

However, this new research  has shown there could be a wireless, non-invasive alternative to clearing the blockage in a shunt. It has shown that a swarm of hundreds of microrobots—made of nano size magnetic nanoparticles—injected into the shunt could remove the sediment instead.

Once the magnetic microrobots are injected into the shunt they can be moved along the tube to the affected area using a magnetic field, generated by a powerful magnet on the body's surface. The swarm of microrobots can then be moved so they scrape away the sediment, clearing the tube.

"The non-invasive nature of this method is a considerable advantage to existing methods as it will potentially eliminate the risk of surgery and a surgery-related infection, thereby decreasing recovery time.

With each microrobot smaller than the width of a human hair, once the swarm has done its job, it can either be guided to the stomach via a magnetic field or bodily fluid, so they leave the body naturally. Because the microrobots have very high biocompatibility they will not cause toxicity.

The research also found a direct relation between the strength of the magnetic field and the success of scraping away the sediment in the shunt.

This is the first proof-of-concept experiment using microswarms for opening a blockage in a shunt.

A. Moghanizadeh et al, A novel non-invasive intervention for removing occlusions from shunts using an abrading magnetic microswarm, IEEE Transactions on Biomedical Engineering (2022). DOI: 10.1109/TBME.2022.3192807

Comment by Dr. Krishna Kumari Challa on August 19, 2022 at 8:14am

'Forever chemicals' destroyed by simple new method

PFAS, a group of manufactured chemicals commonly used since the 1940s, are called "forever chemicals" for a reason. Bacteria can't eat them; fire can't incinerate them; and water can't dilute them. And, if these toxic chemicals are buried, they leach into surrounding soil, becoming a persistent problem for generations to come.

Now chemists have done the seemingly impossible. Using low temperatures and inexpensive, common reagents, the research team developed a process that causes two major classes of PFAS compounds to fall apart, leaving behind only benign end products. The simple technique potentially could be a powerful solution for finally disposing of these harmful chemicals, which are linked to many dangerous health effects in humans, livestock and the environment.

Even just a tiny, tiny amount of PFAS causes negative health effects, and it does not break down. We can't just wait out this problem.

The secret to PFAS's indestructibility lies in its chemical bonds. PFAS contains many carbon-fluorine bonds, which are the strongest bonds in organic chemistry. As the most electronegative element in the periodic table, fluorine wants electrons, and badly. Carbon, on the other hand, is more willing to give up its electrons.

"When you have that kind of difference between two atoms—and they are roughly the same size, which carbon and fluorine are—that's the recipe for a really strong bond.

Scientists now  found a weakness. PFAS contains a long tail of unyielding carbon-fluorine bonds. But at one end of the molecule, there is a charged group that often contains charged oxygen atoms. Researchers targeted this head group by heating the PFAS in dimethyl sulfoxide—an unusual solvent for PFAS destruction—with sodium hydroxide, a common reagent. The process decapitated the head group, leaving behind a reactive tail.

That triggered all these reactions, and it started spitting out fluorine atoms from these compounds to form fluoride, which is the safest form of fluorine.

After discovering the PFAS degradation conditions, researchers also discovered that the fluorinated pollutants fall apart by different processes than generally assumed. A simulation showed that PFAS actually falls apart two or three carbons at a time—a discovery that matched the researchers' experiments. By understanding these pathways, researchers can confirm that only benign products remain. This new knowledge also could help guide further improvements to the method.

Brittany Trang et al, Low-temperature mineralization of perfluorocarboxylic acids, Science (2022). DOI: 10.1126/science.abm8868. www.science.org/doi/10.1126/science.abm8868

Comment by Dr. Krishna Kumari Challa on August 18, 2022 at 10:38am

Modern pesticides damage the brain of bees so they can't move in a straight line

The challenge to let people walk back and forth in a straight line isn't just used by police to test if drivers are intoxicated: it's also used by neurologists to diagnose neurological disorders like ataxia, where parts of the brain that coordinate movement are impaired. Now, researchers use an insect version of this challenge to show for the first time that modern pesticides damage the nervous system of honeybees so that it becomes hard for them to walk in a straight line. The results are published in Frontiers in Insect Science.

The commonly used insecticides like sulfoxaflor and the neonicotinoid imidacloprid can profoundly impair the visually guided behavior of honeybees. New research results are reason for concern because the ability of bees to respond appropriately to visual information is crucial for their flight and navigation, and thus their survival.

The results add to what the Food and Agriculture Organization of the United Nations and the World Health Organization have called the "rapidly growing body of evidence [which] strongly suggests that the existing levels of environmental contamination [from neonicotinoid pesticides] are causing large-scale adverse effects on bees and other beneficial insects."

The researchers also show with molecular techniques that pesticide-exposed bees tended to have elevated proportion of dead cells in parts of the brain's optic lobes, important for processing visual input. Likewise, key genes for detoxification were dysregulated after exposure.

Rachel H. Parkinson et al, Honeybee optomotor behaviour is impaired by chronic exposure to insecticides, Frontiers in Insect Science (2022). DOI: 10.3389/finsc.2022.936826

Comment by Dr. Krishna Kumari Challa on August 18, 2022 at 10:32am

Adults who, as children, had half their brain removed still able to score well with face and word recognition

A team of researchers at Carnegie Mellon University's Department of Psychology and Neuroscience Institute has found that adults who had a hemispherectomy as a child scored surprisingly well on face and word recognition tests. Their paper is posted on the bioRxiv preprint server. In epilepsy, abnormal brain activity results in chronic seizures. Some people respond well to medication and others due not; for example, some people experience seizures so often that they become incapacitating. Some young patients in these circumstances are given the option of undergoing a hemispherectomy, the complete removal of the left or right hemisphere of the brain. Prior research has shown that these procedures, when done at a very young age, allow most patients to retain their IQ and their ability to communicate and live relatively normal lives. In sharp contrast, damage to either hemisphere, much less removal of one or the other in adults, leads to severe symptoms or death. In this new effort, the researchers sought to learn more about the cognitive abilities of adults who had undergone a hemispherectomy. Forty subjects were shown grayscale pictures of human faces without hair for 750 milliseconds, followed by a pause of 150 milliseconds. Then another face was shown for 150 milliseconds after which the volunteer reported whether it was the same face or not. The whole process was then repeated several times with different faces. The researchers then repeated the entire exercise but used simple, four-letter words. The researchers expected that those volunteers who had only their right hemisphere would do well at face recognition but not as well at word recognition, since the right hemisphere is generally used to process images while the left hemisphere processes words; they expected the opposite results for those who still had just their left hemisphere. Instead, the researchers found that both groups performed nearly equally well and both were on average 86% accurate on the tests compared to a control group consisting of people who had not undergone an hemispherectomy, with average 96% accuracy. The researchers also conducted a nearly identical experiment in which the faces and words were shown off to the left or right; both groups still did surprisingly well—but there was one interesting difference. In comparing their results with the control group, those who had undergone a hemispherectomy did as well as the control group in identifying images or words in two instances—when a word was placed on the left side, or a face on the right.

Michael C. Granovetter et al, With Childhood Hemispherectomy, One Hemisphere Can Support—But is Suboptimal for—Word and Face Recognition (2020). DOI: 10.1101/2020.11.06.371823

Comment by Dr. Krishna Kumari Challa on August 18, 2022 at 9:22am

Pre-fertilization DNA transfer to avoid mitochondrial disease inheritance appears safe

Transferring the nuclear genome from one egg into the cytoplasm of a donor egg is a strategy to enable women carrying mutations in their mitochondrial DNA to have healthy babies. A new study  published August 16 in the open-access journal PLOS Biology, uses multiple "omics" techniques to show that this strategy, called spindle transfer, is likely to be safe, with little evidence of genetic or functional difference between the resulting embryos and healthy control in vitro fertilization (IVF) embryos. The results are likely to spur further adoption of spindle transfer for IVF when there is a risk of mitochondrial disease.

Mitochondria, the energy powerhouses of the cell, contain their own DNA, mutations in which can cause a variety of inherited diseases, including metabolic, muscular, and neurologic disorders. In human reproduction, only maternal mitochondria, contained in the egg, are inherited. To interrupt that inheritance, techniques have been developed to place parental nuclear DNA into cytoplasm from donor cells carrying healthy mitochondria, either just before fertilization (spindle transfer), or just after (pronuclear transfer).

The "spindle" refers to the division apparatus that holds the nuclear chromosomes in suspension until fertilization. During spindle transfer, the maternal spindle is removed from an unfertilized egg and placed into a donor egg that has had its own spindle removed. (Pronuclear transfer removes the pronucleus, containing both egg and sperm DNA, and places it in a donor embryo whose pronucleus has been removed.) Spindle transfer has been used clinically, but there remain questions about its safety.

To shed light on this question, the authors performed three different types of analyses on single cells from 23 blastocysts following spindle transfer and compared them to 23 control IVF blastocysts. (The blastocyst is the multicellular ball that forms about 5 or 6 days after fertilization, ready for implantation into the uterine wall.) They found no difference in DNA copy number, a measure of genomic integrity, between spindle transfer and control blastocysts. RNA expression profiles were also similar between the two blastocyst types, regardless of which layer of the blastocyst the cells were taken from.

The authors did find a small but significant reduction in the level of DNA demethylation in spindle transfer blastocysts in one layer, the trophectoderm, though not in two other layers. DNA demethylation is one of the processes used to increase gene expression during development, and their analysis suggested that the reduction was evidence of a slight delay in the process, rather than a permanent inability to upregulate the affected genes. It is quite possible that after the blastocyst stage, the spindle transfer embryos can catch up to complete DNA demethylation before implantation.

The researchers concluded that the spindle transfer seems generally safe and does not severely disturb embryonic development. However, given the limitation of the study, more dimensions and larger-scale evaluations are still needed to determine whether this technique can be applied to a wider set of clinical trials.

Single-cell multiomics analyses of spindle-transferred human embryos suggest a mostly normal embryonic development, PLoS Biology (2022). DOI: 10.1371/journal.pbio.3001741

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Comment by Dr. Krishna Kumari Challa on August 18, 2022 at 9:08am

Young mice transfused with blood from old mice became fatigued faster and ran shorter distances

A team of researchers from Korea University College of Medicine, the University of California and the Buck Institute for Research on Aging reports that transfusing young mice with blood from older mice makes them grow fatigued and unable to run long distances. The study is published in the journal Nature Metabolism. In 2005, a team of researchers at the University of California stitched pairs of old/young mice together to learn more about the aging process—in that effort, the mice were conjoined; they shared not only blood, but some organs. Testing of the older mice showed that the infusion of younger blood resulted in the reversal of some signs of aging. In this new effort, the researchers tested the process in reverse without resorting to conjoining. The work involved transfusing blood from an aged, two-year-old mouse into mice that were just three months old every day for a week, and then studying the young mice to measure the impact. Putting the mice on a treadmill and getting them to run showed that the young mice became fatigued faster and were not able to run as far as a control group (young mice transfused with blood from other young mice.) The young mice transfused with the blood of older mice showed markers for aging of the liver and kidney damage. The researchers also ran the experiment in reverse, giving old mice young blood, which resulted in reductions in fibrosis and lipids—and also fatigue. There was also an increase in endurance. The researchers suggest that it is likely that cells in the blood of older mice held a senescence-associated secretory phenotype, leading to muscle weakness, tissue damage and other signs of aging in the transfused younger mice. They suggest it also seems possible that cells in the blood from the older mice had ceased reproducing and were having an impact on the younger cells. The researchers also took an indirect approach to testing whether similar results might be observed in humans—they placed cells taken from an older person into plasma from a younger person. Six days later, they found biomarkers of aging.

Ok Hee Jeon et al, Systemic induction of senescence in young mice after single heterochronic blood exchange, Nature Metabolism (2022). DOI: 10.1038/s42255-022-00609-6

Comment by Dr. Krishna Kumari Challa on August 18, 2022 at 8:51am

The entanglement of two quantum memory systems 12.5 km apart from each other

Quantum computing technology could have notable advantages over classical computing technology, including a faster speed and the ability to tackle more complex problems. In recent years, some researchers have also been exploring the possible establishment of a "quantum internet," a network that would allow quantum devices to exchange information, just like classical computing devices exchange information today.

The quantum internet could open fascinating possibilities for numerous quantum technology applications. For instance, it could enable more secure communications, more precise remote sensing and distributed quantum computing networks.

Researchers at the University of Science and Technology of China and Jinan Institute of Quantum Technology have recently demonstrated quantum entanglement  between two memory devices located at 12.5 km apart from each other within an urban environment. Their paper, published in Physical Review Letters, could be a further step towards the development of a quantum internet.

In their experiment, researchers  introduced two quantum nodes in different locations in an urban environment, placing them at a 12.5 km distance from one another. In the first node, dubbed node A, they entangled their first quantum memory with a single photon. This single photon was then sent to node B and stored within the second quantum memory.

In this way they entangled the two remote quantum memories.

Xi-Yu Luo et al, Postselected Entanglement between Two Atomic Ensembles Separated by 12.5 km, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.129.050503

Yong Yu et al, Entanglement of two quantum memories via fibres over dozens of kilometres, Nature (2020). DOI: 10.1038/s41586-020-1976-7

Comment by Dr. Krishna Kumari Challa on August 17, 2022 at 9:20am

Potential anti-aging components of Moringa oleifera leaf

Moringa oleifera Lam., also known as drum stick and Miracle Tree, primarily derived from India, is now widely distributed in tropical and subtropical regions. Previous studies have showed that M. oleifera has anti-aging effects, but there is a lack of in-depth research on the specific active ingredients and mechanisms of this anti-aging activity. Researchers are working to screen out the most effective active components of M. oleifera leaves.

Scientists in China conducted in vitro elastase and collagenase enzyme inhibitory assays to evaluate the activities of M. oleifera leaf extracts.

They found that M. oleifera leaf extracts possessed promising anti-elastase and anti-collagenase activities. Then, 10, 8, and 14 potential bioactive phytochemicals were screened out from M. oleifera leaf extracts against elastase, collagenase and hyaluronidase using the multi-target bio-affinity ultrafiltration coupled to high-performance liquid chromatography-mass spectrometry (AUF-HPLC-MS), respectively. In addition, further verification of representative active components was completed with molecular docking analysis. Results showed that these potentially active compounds could form hydrogen bonds with amino acid residues Asn112, Trp115, Glu141, Glu164, and Asp221 of elastase, Arg214, Val215, Glu219, and Pro238 of collagenase, Arg47, Asp56, Gly58, Asp111, Glu113, and Ser304 of hyaluronidase, respectively. These hydrogen bonds enhanced the binding ability of active small molecules to biological target molecules. This is the first study to comprehensively demonstrate M. oleifera leaves possess the significant elastase and collagenase inhibitory activities in vitro and reveal its potential bioactive components as well as the mechanism of anti-aging activity.

This work provides a theoretical basis for its further development into functional anti-aging products in the cosmetics and cosmeceutical industries combating aging and skin wrinkling.

Yongbing Xu et al, Potential Anti-aging Components From Moringa oleifera Leaves Explored by Affinity Ultrafiltration With Multiple Drug Targets, Frontiers in Nutrition (2022). DOI: 10.3389/fnut.2022.854882

Comment by Dr. Krishna Kumari Challa on August 17, 2022 at 7:04am

Nuclear war would cause a global famine and kill billions, study finds

More than 5 billion people would die of hunger following a full-scale nuclear war between the U.S. and Russia, according to a global study led by Rutgers climate scientists that estimates post-conflict crop production.

Building on past research, researchers now worked to calculate how much sun-blocking soot would enter the atmosphere from firestorms that would be ignited by the detonation of nuclear weapons. Researchers calculated soot dispersal from six war scenarios—five smaller India-Pakistan wars and a large U.S.-Russia war—based on the size of each country's nuclear arsenal.

These data then were entered into the Community Earth System Model, a climate forecasting tool supported by the National Center for Atmospheric Research (NCAR). The NCAR Community Land Model made it possible to estimate productivity of major crops (maize, rice, spring wheat and soybean) on a country-by-country basis. The researchers also examined projected changes to livestock pasture and in global marine fisheries.

Under even the smallest nuclear scenario, a localized war between India and Pakistan, global average caloric production decreased 7% within five years of the conflict. In the largest war scenario tested—a full-scale U.S.-Russia nuclear conflict—global average caloric production decreased by about 90% three to four years after the fighting.

Crop declines would be the most severe in the mid-high latitude nations, including major exporting countries such as Russia and the U.S., which could trigger export restrictions and cause severe disruptions in import-dependent countries in Africa and the Middle East.

These changes would induce a catastrophic disruption of global food markets, the researchers conclude. Even a 7% global decline in crop yield would exceed the largest anomaly ever recorded since the beginning of Food and Agricultural Organization observational records in 1961. Under the largest war scenario, more than 75% of the planet would be starving within two years.

Researchers considered whether using crops fed to livestock as human food or reducing food waste could offset caloric losses in a war's immediate aftermath, but the savings were minimal under the large injection scenarios.

Moreover, the ozone layer would be destroyed by the heating of the stratosphere, producing more ultraviolet radiation at the surface, and we need to understand that impact on food supplies too.

The data tell us one thing: We must prevent a nuclear war from ever happening.

Lili Xia, Global food insecurity and famine from reduced crop, marine fishery and livestock production due to climate disruption from nuclear war soot injection, Nature Food (2022). DOI: 10.1038/s43016-022-00573-0. www.nature.com/articles/s43016-022-00573-0

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