Comment

Comment by Dr. Krishna Kumari Challa on October 25, 2022 at 11:37am

Plastic recycling remains a 'myth':  study

Plastic recycling rates are declining even as production shoots up, according to a Greenpeace U.S. report out Monday that blasted industry claims of creating an efficient, circular economy as "fiction."

Titled "Circular Claims Fall Flat Again," the study found that of 51 million tons of plastic waste generated by US households in 2021, only 2.4 million tons were recycled, or around five percent.

After peaking in 2014 at 10 percent, the trend has been decreasing, especially since China stopped accepting the West's plastic waste in 2018.

Virgin production—of non-recycled plastic, that is—meanwhile is rapidly rising as the petrochemical industry expands, lowering costs.

Plastic waste is generated in vast quantities and is extremely difficult to collect— as becomes clear during what the report called ineffective "volunteer cleanup stunts".

Even if it were all collected, mixed plastic waste cannot be recycled together, and it would be "functionally impossible to sort the trillions of pieces of consumer plastic waste produced each year". 

Moreover,  the recycling process itself is environmentally harmful, exposing workers to toxic chemicals and itself generating microplastics.

Then recycled plastic carries toxicity risks through contamination with other plastic types in collection bins, preventing it from becoming food-grade material again. 

The most important point is  the process of recycling is prohibitively expensive.New plastic directly competes with recycled plastic, and it's far cheaper to produce and of higher quality. So people rarely tread this path.

Source: AFP

Comment by Dr. Krishna Kumari Challa on October 25, 2022 at 11:26am

How heart failure disrupts the cell's mitochondria

Chronic heart failure causes the cell's powerhouses to malfunction, in part due to overconsumption of an important intermediary compound in energy production. Supplementing the diet to compensate for this could prove a promising strategy for treating heart failure.

Mitochondria are small organelles found in almost every cell and are responsible for converting carbohydrates, fats and proteins into energy to power biochemical reactions. Chronic heart failure is known to be associated with mitochondrial dysfunction, but much is still unknown about how this happens at the molecular level.

A research team 

studied the biochemical processes that occur in mice with chronic heart failure caused by surgically blocking part of the blood supply to their hearts. They specifically looked at heart cells outside the boundaries of dead tissue.

They found a significant reduction in a compound called succinyl-CoA, which is an intermediary in the cell's tricarboxylic acid cycle. This cycle, which happens inside mitochondria, plays an important role in breaking down organic molecules to release energy.

Further investigations revealed that this reduction of succinyl-CoA levels was at least in part caused by its overconsumption for the synthesis of heme, which is essential for mitochondrial oxidative phosphorylation. This latter process is needed for transferring and synthesizing energy-carrying and storage molecules by mitochondria.

Adding a compound called 5-aminolevulinate acid (5-ALA) to the drinking water of mice immediately after cutting off the blood supply to part of the heart significantly improved their heart function, treadmill running capacity and survival. At the molecular level, it improved the oxidative phosphorylation capacity of heart muscle mitochondria and appeared to restore their succinyl-CoA levels.

Further research is needed to clarify other factors involved in reducing mitochondrial succinyl-CoA levels in heart failure. For example, the scientists found evidence that succinyl-CoA may also be overconsumed in heart failure-affected mitochondria in order to break down ketones as a source of energy. But more investigations are needed to understand why this might happen and whether there really is a direct link between the two.

Shingo Takada et al, Succinyl-CoA-based energy metabolism dysfunction in chronic heart failure, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2203628119

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Comment by Dr. Krishna Kumari Challa on October 25, 2022 at 10:43am

Study explains why adults' hearts don't regenerate

While skin and many other tissues of the human body retain the ability to repair themselves after injury, the same isn't true of the heart. During human embryonic and fetal development, heart cells undergo cell division to form the heart muscle. But as heart cells mature in adulthood, they enter a terminal state in which they can no longer divide.

As heart cells mature in mice, the number of communication pathways called nuclear pores dramatically decreases, according to new research . While this might protect the organ from damaging signals, it could also prevent adult heart cells from regenerating, the researchers found.

The study suggests that quieting communication between heart cells and their environment protects this organ from harmful signals related to stresses such as high blood pressure, but at the cost of preventing heart cells from receiving signals that promote regeneration.

This work provides an explanation for why adult hearts do not regenerate themselves, but newborn mice and human hearts do. These findings are an important advance in fundamental understanding of how the heart develops with age and how it has evolved to cope with stress.

Bernhard Kühn, Changes in nuclear pore numbers control nuclear import and stress response of mouse hearts, Developmental Cell (2022). DOI: 10.1016/j.devcel.2022.09.017. www.cell.com/developmental-cel … 1534-5807(22)00719-5

Comment by Dr. Krishna Kumari Challa on October 25, 2022 at 9:37am

During sleep, one brain region teaches another, converting novel data into enduring memories

What role do the stages of sleep play in forming memories?

We've known for a long time that useful learning happens during sleep. You encode new experiences while you're awake, you go to sleep, and when you wake up your memory has somehow been transformed.

Yet precisely how new experiences get processed during sleep has remained mostly a mystery. Using a neural network computational model they built, researchers now have new insight into the process.

In research published in the Proceedings of the National Academy of Sciences, they show that as the brain cycles through slow-wave and rapid-eye movement (REM) sleep, which happens about five times a night, the hippocampus teaches the neocortex what it learned, transforming novel, fleeting information into enduring memory. This is not just a model of learning in local circuits in the brain. It's how one brain region can teach another brain region during sleep, a time when there is no guidance from the external world.

The team ran several sleep simulations using a brain-inspired learning algorithm they built. The simulations revealed that during slow-wave sleep, the brain mostly revisits recent incidents and data, guided by the hippocampus, and during REM sleep, it mostly reruns what happened previously, guided by memory storage in the neocortical regions. As the two brain regions connect during non-REM sleep, that's when the hippocampus is actually teaching the neocortex. Then, during the REM phase, the neocortex reactivates and can replay what it already knows, solidifying the data's hold in long-term memory.

When the neocortex doesn't have a chance to replay its own information, we see that the information there gets overwritten. Scientists think you need to have alternating REM and non-REM sleep for strong memory formation to occur.

This needs to be tested further to confirm, though. 

Singh, Dhairyya et al, A model of autonomous interactions between hippocampus and neocortex driving sleep-dependent memory consolidation, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2123432119. doi.org/10.1073/pnas.2123432119

Comment by Dr. Krishna Kumari Challa on October 24, 2022 at 11:31am

NEOWISE: Revealing Changes in the Universe

Comment by Dr. Krishna Kumari Challa on October 24, 2022 at 11:16am

Particle Physics Could Reduce The 'Collateral Damage' of Cancer Treatments

Researchers at Europe's science lab CERN, who regularly use particle physics to challenge our understanding of the universe, are also applying their craft to upend the limits to cancer treatment.

The physicists here are working with giant particle accelerators in search of ways to expand the reach of cancer radiation therapy, and take on hard-to-reach tumors that would otherwise have been fatal.

In one CERN lab, called CLEAR, the research is aimed at creating very high energy beams of electrons – the negatively charged particles in the atom – that eventually could help to combat cancerous cells more effectively. They are researching a "technology to accelerate electrons to the energies that are needed to treat deep-seated tumors, which is above 100 million electron volts" (MeV)

The idea is to use these very high-energy electrons (VHEE) in combination with a new and promising treatment method called FLASH.

This method entails delivering the radiation dose in a few hundred milliseconds, instead of minutes as is the current approach.

This has been shown to have the same destructive effect on the targeted tumor but causes far less damage to the surrounding healthy tissue. The effect of the brief but intense FLASH treatment is to "reduce the toxicity to healthy tissue while still properly damaging cancer cells".

At such low energy though, the beams cannot penetrate deeply, meaning the highly-effective treatment has so far only been used on superficial tumors, found with skin cancer.

But the CERN physicists are now collaborating with the Lausanne University Hospital (CHUV) to build a machine for FLASH delivery that can accelerate electrons to 100 to 200 MeV, making it possible to use the method for much more hard-to-reach tumors.

source: new agencies

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

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