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Comment by Dr. Krishna Kumari Challa on October 24, 2022 at 9:49am

Breaking the sound barriers without the sonic boom

Seventy-five years ago, a sonic boom thundered for the first time over the high desert of California.

It was Oct. 14, 1947, and the joint X-1 team of NACA, Air Force (newly formed that year), and Bell engineers and pilots had broken the sound barrier —an imaginary wall in the sky some said was impossible to penetrate.

Now, aeronautical innovators with NASA's Quesst mission are poised to break the sound barrier again, only this time in a very different way that could make it possible for all of us to one day travel by air just as fast as any of the X-1 pilots who flew supersonic. With X-59.

Through Quesst, NASA plans to demonstrate the X-59 can fly faster than sound without generating the typically loud sonic booms.

Researchers gained a greater understanding of how aircraft create sonic booms and turned their attention the idea of lowering the intensity of the sonic booms by manipulating the shape of the airplane.

That idea was tested in flight by NASA's Shaped Sonic Boom Demonstration program during 2003–2004. It used a Northrop F-5E jet whose fuselage was modified to give it a shape designed to produce quieter sonic booms.

And it worked now. First flight of the X-59 is targeted for early 2023.

Source: NASA

Comment by Dr. Krishna Kumari Challa on October 23, 2022 at 9:57am

Why NASA is trying to crash land on Mars

 Like a car’s crumple zone, the experimental SHIELD lander is designed to absorb a hard impact.

NASA has successfully touched down on Mars nine times, relying on cutting-edge parachutes, massive airbags, and jetpacks to set spacecraft safely on the surface. Now engineers are testing whether or not the easiest way to get to the Martian surface is to crash.

Rather than slow a spacecraft’s high-speed descent, an experimental lander design called SHIELD (Simplified High Impact Energy Landing Device) would use an accordion-like, collapsible base that acts like the crumple zone of a car and absorbs the energy of a hard impact.

The new design could drastically reduce the cost of landing on Mars by simplifying the harrowing entry, descent, and landing process and expanding options for possible landing sites.

https://researchnews.cc/news/15986/Why-NASA-is-trying-to-crash-land...

Comment by Dr. Krishna Kumari Challa on October 22, 2022 at 11:26am

Increased thermogenesis in fat cells during active period of circadian rhythm limits weight gain in mice

A team of researchers has found that an increase in thermogenesis in fat cells during active periods of the daily circadian rhythm can limit weight gain in mice.

Prior research has shown that overeating during the inactive phase of the circadian rhythm in mice and humans can lead to higher levels of weight gain. Likewise, adhering to time-restricted feeding (TRF) can lead to less weight gain. But until now, why this happens has not been fully understood. To learn more about the effects of a high-fat diet on mice over phases of the circadian rhythm, the researchers fed two groups of mice a high-fat diet. One group was fed during their active phase (when it was dark out) and the other was fed during their inactive phase (when it was light out.) They then took a close look at what was occurring in the fat cells of both groups. The researchers found that the mice fed during their inactive phase gained more weight, as expected. But they also learned more about the factors behind such a weight gain. One of the biggest was thermogenesis, the process by which heat is generated in the body. They found that an increase in thermogenesis in fat cells during the active phase of the circadian rhythm (due to a boost in creatine in fat cells) was at least partly responsible for restricting weight gain. They also found that a zinc finger protein can block the genes responsible for producing the chemicals that regulate thermogenesis by controlling production of adenosine triphosphate. They conclude that their work has helped to explain why TRF can play such an important role in weight management.

Chelsea Hepler et al, Time-restricted feeding mitigates obesity through adipocyte thermogenesis, Science (2022). DOI: 10.1126/science.abl8007

Damien Lagarde et al, The timing of eating controls energy use, Science (2022). DOI: 10.1126/science.ade6720

Comment by Dr. Krishna Kumari Challa on October 22, 2022 at 8:43am

Disruption of gut microbial balance is associated with increased mortality after kidney, liver transplants

Disruptions in the gut microbiome have been linked to lower survival rates for people who have undergone kidney and liver transplants, a finding that highlights the critical importance of the vast and complex microbial communities that dwell within us.

Scientists studied  faecal samples from more than 1,000 recipients of kidney and liver transplants to learn how the balance of microbes in the gut microbiome impact post-transplant survival. Gut microbiome dysbiosis—disruptions in microbial diversity—is associated with increased mortality after solid organ transplantation, researchers found.

The gut microbiome is made up of both "good" and "bad" microbes: bacteria, viruses and fungi. Health benefits throughout the body are derived from the healthy balance of these microbial communities in the gut. However, the living communities are not static; they fluctuate in response to diet, emotions, exercise, surgery, and exposure to medications.

Past studies demonstrated that recipients of stem cell transplants had a higher mortality risk when faced with disruptions in their gut microbiome. It has taken until now to pose the same question, based on a large sample size, whether microbiota disruption negatively impacts recipients of solid organ transplants.

They were aware that the health of the microbiome influenced the fate of patients who had undergone stem cell transplants, infusions that are sometimes referred to as bone marrow transplants. The procedure provides the recipient with a donor's healthy progenitor cells to generate a new blood supply. But scientists also were aware that a successful stem cell transplant wasn't enough unless the gut microbiome was also flourishing with a diverse population of beneficial microbes.

The researchers reported  on the need for microbial variety to ensure a healthy transplant outcome.

J. Casper Swarte et al, Gut microbiome dysbiosis is associated with increased mortality after solid organ transplantation, Science Translational Medicine (2022). DOI: 10.1126/scitranslmed.abn7566

Comment by Dr. Krishna Kumari Challa on October 21, 2022 at 9:37am

Metallic water prepared for first time under terrestrial conditions

Inside a vacuum chamber, the researchers expose a drop of sodium-potassium alloy to a small amount of water vapor, which begins to condense on its surface. The electrons liberated from the alkali metal dissolve in the layer of water on the surface faster than the chemical reaction that results in the explosion. There are a sufficient number of them to overcome the critical limit for the formation of a conduction band and thus give rise to a metallic water solution.

https://www.sciencealert.com/scientists-transformed-pure-water-into...

Comment by Dr. Krishna Kumari Challa on October 21, 2022 at 8:58am

Alligators exposed to PFAS show autoimmune effects

A recent study of alligators  found the animals had elevated levels of 14 different per- and polyfluoroalkyl (PFAS) chemicals in their blood serum, as well as clinical and genetic indicators of immune system effects. The work adds to the body of evidence connecting PFAS exposure with adverse immune system effects.

Researchers took blood samples and did health evaluations on 49 alligators living along the Cape Fear River between 2018 and 2019. They compared these results to a reference population of 26 alligators from Lake Waccamaw, located in the adjoining Lumber River basin.

They  looked at 23 different PFAS and saw clear differences between both types and levels of PFAS in the two populations. The most unusual observation the team made was that alligators in the Cape Fear River which had high concentration of PFAS also had a number of unhealed or infected lesions.

Alligators rarely suffer from infections. They do get wounds, but they normally heal quickly. Seeing infected lesions that weren't healing properly was concerning and led the scientists  to look more closely at the connections between PFAS exposure and changes in the immune systems of the alligators.

A qRT-PCR genetic analysis revealed significantly elevated levels of interferon-alpha (INF-α) responsive genes in the Cape Fear River alligators: their levels were 400 times higher than those of the low level PFAS containing alligators, 

INF-α is a secreted immune protein involved in stimulating immune response.The set of INF-α responsive genes we analyzed are normally involved with viral infections. In humans, chronic (or long-term) high expression of this set of genes is an important indicator of autoimmune diseases, especially lupus. Additionally, some PFAS exposures in humans are linked with chronic autoimmune disorders like ulcerative colitis and thyroid disease. 

The elevated expression of INF-α in these alligators tells us that something in these alligators' immune responses is being disrupted.

Blood Concentrations of Per- and Polyfluoroalkyl Substances are Associated with Autoimmune-like Effects in American Alligators from Wilmington, North Carolina, Frontiers in Toxicology (2022). DOI: 10.3389/ftox.2022.1010185

Comment by Dr. Krishna Kumari Challa on October 21, 2022 at 8:10am

Injecting extracellular vesicles from young mice into older mice found to reduce some signs of aging

A team of researchers has found that injecting older mice with extracellular vesicles (EVs) from young mice reduced some signs of aging. 

EVs, which are also known as exosomes, are structures produced in eukaryotic cells that are involved in signaling between cells and also used for transporting mRNA. Suspecting that aspects of the aging process might be related to degeneration in communication between cells, the researchers wondered what would happen if they injected older mice with EVs. To find out, they extracted stem cells from fatty tissue in young test mice. Next, they collected EVs that were produced by the cells they had collected. They then injected the EVs into the tails of older mice—once at the outset of the test and again a week later.

The researchers then began studying the mice to see what impact the injections might have. They found that after just two weeks, the mice showed improvements in physical strength, suggesting reductions in age-related muscle degeneration. They also found the mice tired less easily and tended to be better coordinated—and their fur grew back more quickly. The team noted that the improvements peaked at approximately 30 days after the initial injection and disappeared after approximately 60 days.

The researchers also dissected some of the test mice and found reductions in degeneration of kidney tissue and an increase in cell production. They also found reductions in inflammatory biomarkers and that some tissue appeared to be epigenetically younger.

Jorge Sanz-Ros et al, Small extracellular vesicles from young adipose-derived stem cells prevent frailty, improve health span, and decrease epigenetic age in old mice, Science Advances (2022). DOI: 10.1126/sciadv.abq2226

Comment by Dr. Krishna Kumari Challa on October 20, 2022 at 6:06am

Analysis shows women who publish physics papers are cited less often than men

A team of researchers affiliated with multiple institutions in the U.S. has found that women who publish physics papers are cited less often than are men. In their paper published in the journal Nature Physics, the group describes their analysis of more than 1 million published papers in multiple journals.

Prior research and anecdotal evidence have suggested that women are greatly underrepresented in the sciences, particularly chemistry, physics and math. Prior research has also shown that there are a number of reasons for the differences, among them, simple discrimination. In this new effort, the researchers looked at one type of discrimination—underciting papers based on gender—that could play a role in the underrepresentation of women in physics.

One of the ways that scientists measure prestige in their field is by the number of times their publications are cited. A high number of citations for a given paper also suggests that the work was both insightful and impactful on the field in which a paper has been published. Thus, a dearth of citations by a given scientist or paper could suggest that the work did little to advance the science involved. But it could also suggest that a bias exists in the science community that makes it more difficult for some members to collect citations.

The researchers 

studied approximately 1.07 million physics papers published over the years 1995 to 2020 in 35 well-established journals. Their effort involved counting the number of citations made for all of the papers and noting whether the authors of the paper were male or female (as determined by their forename).

The researchers found that papers published by men (where the first and last authors listed were male) were on average 4.23% more likely to be cited. This, they contend, shows that there is a gender bias that favors citing male colleagues over those who are female. They conclude by suggesting ways to reduce this bias, such as having researchers sign diversity statements or holding publishers more accountable.

 Erin G. Teich et al, Citation inequity and gendered citation practices in contemporary physics, Nature Physics (2022). DOI: 10.1038/s41567-022-01770-1

Comment by Dr. Krishna Kumari Challa on October 20, 2022 at 5:53am

When a macrophage encounters a bacterium, it chops it into pieces for them to be presented to other immune cells signaling that there's an infection. Having the functional version of the gene, appears to create an advantage, likely by enhancing the ability of our immune system to sense the invading pathogen. By the researchers' estimate, possessing two copies of the rs2549794 variant would have make a person about 40% more likely to survive the Black Death than those who had two copies of the non-functional variant.

The team even went so far as to test how the rs2549794 variant affected the ability of living human cells to help fight the plague, determining that macrophages expressing two copies of the variant were more efficient at neutralizing Y. pestis compared to those without it.

Examining the effects of the ERAP2 variants in vitro allowed teh scientists to functionally test how the different variants affect the behavior of immune cells from modern humans when challenged with living Yersinia pestis.

Luis Barreiro, Evolution of immune genes is associated with the Black Death, Nature (2022). DOI: 10.1038/s41586-022-05349-x. www.nature.com/articles/s41586-022-05349-x

Selection of human immune-related genes was driven by the Black Death

The Black Death shaped the evolution of immunity genes

Part 2**

Comment by Dr. Krishna Kumari Challa on October 20, 2022 at 5:49am

Selection of human immune-related genes was driven by the Black Death

The Black Death was the single greatest mortality event in recorded history, killing up to 50% of the European population in less than five years. New research has found evidence that one of the darkest periods in recorded human history placed a significant selective pressure on the human population, changing the frequency of certain immune-related genetic variants and affecting our susceptibility to disease today.

Caused by the bacterium Yersinia pestis, the global pandemic of the bubonic plague wiped out 30% to 60% of people in cities across North Africa, Europe, and Asia, with massive repercussions for the human race—and, apparently, our genome.

In the study, thanks to recent advances in sequencing technology, the scientists examined ancient DNA samples from the bones of over 200 individuals from London and Denmark who died before, during, and after the Black Death plague swept through the region in the late 1340s. Using targeted sequencing for a set of 300 immune-related genes, they identified four genes that, depending on the variant, either protected against or increased susceptibility to Y. pestis.

The research team zeroed in on one gene with a particularly strong association to susceptibility: ERAP2. Individuals who possessed two copies of one specific genetic variant, dubbed rs2549794, were able to produce full length copies of the ERAP2 transcript, therefore producing more of the functional protein, compared to another variant that led to a truncated and non-functional version of the transcript. Functional ERAP2 plays a role in helping the immune system recognize the presence of an infection.

Part 1

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