Comment

Comment by Dr. Krishna Kumari Challa yesterday

Researchers make sand that flows uphill

Engineering researchers  have discovered that sand can actually flow uphill.

The team's findings were published recently in the journal Nature Communications. A corresponding video shows what happens when torque and an attractive force  is applied to each grain—the grains flow uphill, up walls, and up and down stairs.

"After using equations that describe the flow of granular materials,"  say the authors of the paper, "we were able to conclusively show that these particles were indeed moving like a granular material, except they were flowing uphill."

The researchers say the highly unusual discovery could unlock many more lines of inquiry that could lead to a vast range of applications, from health care to material transport and agriculture.

Uphill granular flow of microrobotic microrollers

But to understand how these grains are flowing uphill, the researchers calculated what the stresses are that cause them to move in that direction. If you have a negative angle of repose, then you must have cohesion to give a negative coefficient of friction. These granular flow equations were never derived to consider these things, but after calculating it, what came out is an apparent coefficient of friction that is negative.

Increasing the magnetic force increases the cohesion, which gives the grains more traction and the ability to move faster. The collective motion of all those grains, and their ability to stick to each other, allows a pile of sand particles to essentially work together to do counterintuitive things—like flow up walls, and climb stairs. The team is now using a laser cutter to build tiny staircases, and is taking videos of the material ascending one side and descending the other. A single microroller couldn't overcome the height of each step. But working together, they can.

 Samuel R. Wilson-Whitford et al, Microrollers flow uphill as granular media, Nature Communications (2023). DOI: 10.1038/s41467-023-41327-1

Comment by Dr. Krishna Kumari Challa yesterday

Spider silk is spun by silkworms for the first time, offering a green alternative to synthetic fibers

Scientists  have synthesized spider silk from genetically modified silkworms, producing fibers six times tougher than the Kevlar used in bulletproof vests.

The study, published September 20 in the journal Matter, is the first to successfully produce full-length spider silk proteins using silkworms. The findings demonstrate a technique that could be used to manufacture an environmentally friendly alternative to synthetic commercial fibers such as nylon.

Silkworm silk is presently the only animal silk fiber commercialized on a large scale, with well-established rearing techniques. Consequently, employing genetically modified silkworms to produce spider silk fiber enables low-cost, large-scale commercialization.

Scientists have eyed spider silk as an enticingly sustainable alternative to synthetic fibres, which can release harmful microplastics into the environment and are often produced from fossil fuels that generate greenhouse gas emissions. But turning to nature for alternatives isn't without challenges.

Previously developed processes for spinning artificial spider silk have struggled to apply a surface layer of glycoproteins and lipids to the silk to help it withstand humidity and exposure to sunlight—an anti-aging "skin layer" that spiders apply to their webs.

Genetically modified silkworms offer a solution to this problem, say the researchers  since silkworms coat their own fibers with a similar protective layer.

The exceptionally high mechanical performance of the fibers produced in this study holds significant promise in this field. This type of fiber can be utilized as surgical sutures, addressing a global demand exceeding 300 million procedures annually.

The spider silk fibers could also be used to create more comfortable garments and innovative types of bulletproof vests and they may have applications in smart materials, the military, aerospace technology, and biomedical engineering.

 Qing Meng, High-strength and ultra-tough whole spider silk fibers spun from transgenic silkworms, Matter (2023). DOI: 10.1016/j.matt.2023.08.013. www.cell.com/matter/fulltext/S2590-2385(23)00421-6

Comment by Dr. Krishna Kumari Challa on Wednesday

This rate is 35 times higher than previous genus-level extinctions.

Without human influence, it would have taken 18,000 years for the same number of genera to have met their end. Other studies have also found similarly high extinction rates for plant, fungi, and invertebrate life as well.

"[The sixth mass extinction] is causing rapid mutilation of the tree of life, where entire branches (collections of species, genera, families, and so on) and the functions they perform are being lost," explain the researchers.

The biosphere we live within is extremely interconnected, so loss of species groups that play particular functions within their interconnected-living web can have severe cascading consequences.

What's more, this rate of genera loss is set to increase, they calculate. If we continue on our current trajectory and all current endangered genera are snuffed from existence by 2100, the equivalent 300-year-loss since 1800 would have taken 106,000 years at normal background levels of extinction.

The most vulnerable species are usually the most unique, yet overlooked on the planet. Along with them we'll lose millions of years of evolutionary history, which can never be repeated, as well as the loss of critical functions they performed that helped keep all the surrounding biological cycles chugging on like a well oiled machine.

Climate change alone is creating a massive destabilization across these systems, scattering critical timing of ecosystem services like pollination, reducing the types of species and allowing new ones to invade more easily.

From plastics, to pesticides, habitat loss and poaching, we're not allowing the life around us to catch a break.

"Immediate political, economic, and social efforts of an unprecedented scale are essential if we are to prevent these extinctions and their societal impacts. What happens in the next two decades will very likely define the future of biodiversity

https://www.pnas.org/doi/10.1073/pnas.2306987120

Part 2

Comment by Dr. Krishna Kumari Challa on Wednesday

Entire Branches on Tree of Life Are Dying, Scientists Warn

Like the comet striking the dinosaurs – in slower motion, but just as deadly – human activity is hacking off entire branches from the tree of life, a new study confirms.

"It is changing the trajectory of evolution globally and destroying the conditions that make human life possible," ecologists warn in their new paper.

"It is an irreversible threat to the persistence of civilization and the livability of future environments for Homo sapiens."

Over the past few months the sixth mass extinction has become devastatingly visible.

We've witnessed mass seabird deaths, shores have been littered with droves of dead fish, and sea lions poisoned by heat-induced algal blooms. Last year entire populations of penguins failed to breed and for years now researchers have been investigating an alarming reduction in insect life.

Ecologists assessed species extinctions since 1500 CE and compared those through the past 500 million years. They found we've driven 73 genera of back-boned animals to extinction during the last 500 years.

Genus is the taxonomic classification just above species, grouping together the most closely related organisms, much like siblings, in a family tree.

Part 1

Comment by Dr. Krishna Kumari Challa on Wednesday

How brain cells die in Alzheimer’s

It has been a mystery and a source of scientific debate for decades.

But scientists, writing in the journal Science, connect the abnormal proteins that build up in the brain with "necroptosis" - a form of cellular suicide.

It is the loss of brain cells, called neurons, that lead to the symptoms of Alzheimer's, including memory loss.

And if you look inside the brains of people with the disease you'd see the build-up of abnormal proteins called amyloid and tau. But scientists have not been able to join the dots between these key traits of the disease until recently. 

The new work shows that abnormal amyloid starts to build up in the spaces between neurons, leading to brain inflammation, which the neurons do not like. This starts to change their internal chemistry.

Tangles of tau appear and the brain cells start producing a specific molecule (it's called MEG3) that triggers death by necroptosis. Necroptosis is one of the methods our bodies normally use to purge unwanted cells as fresh ones are made.

The brain cells survived when the researchers were able to block MEG3.

It really provides strong evidence it's this specific suicide pathway.

The answers came from experiments where human brain cells were transplanted into the brains of genetically modified mice. The animals were programmed to produce large quantities of abnormal amyloid.

There has been recent success in developing drugs that strip amyloid out of the brain and they mark the first treatments to slow the destruction of brain cells.

https://www.science.org/doi/10.1126/science.abp9556

Comment by Dr. Krishna Kumari Challa on Wednesday

Yogurt may be the next go-to garlic breath remedy

It turns out yogurt may have a previously unknown benefit: eliminating garlic odors.

A new study conducted in a lab—with follow-up human breath tests being planned—showed that whole milk plain yogurt prevented almost all of the volatile compounds responsible for garlic's pungent scent from escaping into the air.

Researchers tested the garlic deodorizing capacity of yogurt and its individual components of water, fat and protein to see how each stood up to the stink. Both fat and protein were effective at trapping garlic odors, leading the scientists to suggest high-protein foods may one day be formulated specifically to fight garlic breath.

For each treatment experiment, the researchers placed equal amounts of raw garlic in glass bottles and confirmed the cluster of offending sulfur-based volatiles were released in concentrations that would be detected by the human nose. They used mass spectrometry to measure levels of the volatile molecules in gaseous form present before and after each treatment.

Results showed that yogurt alone reduced 99% of the major odor-producing raw garlic volatiles. When introduced separately, the fat, water and protein components of yogurt also had a deodorizing effect on raw garlic, but fat and protein performed better than water.

In the case of fat, a higher quantity of butter fat was more effective at deodorization. The proteins studied included different forms of whey, casein and milk proteins, all of which were effective at deodorizing garlic—likely because of their ability to trap the volatile molecules before they were emitted into the air. A casein micelle-whey protein complex performed the best.

Additional experiments involving changing the pH of the yogurt to make it less acidic—from 4.4 pH to 7 pH—reduced the yogurt's deodorization effect on the garlic. Changing the pH of water, on the other hand, did not make any difference in water's deodorization effect.

Manpreet Kaur et al, Effect of Yogurt and Its Components on the Deodorization of Raw and Fried Garlic Volatiles, Molecules (2023). DOI: 10.3390/molecules28155714

Comment by Dr. Krishna Kumari Challa on Wednesday

The researchers found that when water was stratified (a layer of warm water sitting on top of cold bottom waters), methane built up and led to overall higher emissions than when water was mixed by wind or sudden cooling. That's because micro-organisms on the pond bed that produce methane require low-oxygen conditions that is disrupted by mixing.

When the results from the all the present studies are considered together, ponds are net emitters of greenhouse gases, due to methane release overwhelming the amount of carbon stored in the sediments. But the findings also offer the possibility of reducing methane emissions with bubblers or underwater circulators. If we could reduce that methane number, we could potentially flip these ponds from being net emitters to net sinks, but we have to get a handle on that methane.

Meredith A. Holgerson et al, High rates of carbon burial linked to autochthonous production in artificial ponds, Limnology and Oceanography Letters (2023). DOI: 10.1002/lol2.10351

Nicholas E. Ray et al, High Intra‐Seasonal Variability in Greenhouse Gas Emissions From Temperate Constructed Ponds, Geophysical Research Letters (2023). DOI: 10.1029/2023GL104235

Part 2

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Comment by Dr. Krishna Kumari Challa on Wednesday

Research finds ponds release more greenhouse gas than they store

Though human-made ponds both sequester and release greenhouse gases, when added up, they may be net emitters, according to two related studies by  researchers.

The studies begin to quantify the significant effects that both human-made and natural ponds have on the global greenhouse gas budget, measurements that aren't well understood. Global climate models and predictions rely on accurate accounting of greenhouse gas emissions and carbon storage.

In the study, the researchers examined the past management activities, while also taking sediment cores and measurements of sediment thickness for each of the 22 study ponds. They measured the amount of carbon in the sediment, extrapolated those measurements to the overall pond, and divided that number by the age of the pond to arrive at the amount of carbon sequestered annually per square meter, a number on the same order of magnitude as wetlands and mangroves, and more than lakes. They also found that carbon burial rates were influenced by aquatic plants (those large enough to be seen), fish and additions of high nitrogen levels relative to phosphorus, nutrients that may not get renewed in a static pond and become limited. The right kinds and ratios of added nutrients promote plant growth, which use carbon for cells, and are deposited on the pond floor when plants die.

The  researchers also measured gas emissions from the ponds approximately every two weeks over the course of ice-free period in 2021.

The researchers found that methane—a greenhouse gas 25 times more potent than carbon dioxide—accounted for most of the gas emitted annually, and carbon dioxide and methane emissions varied greatly by season.

Ponds absorbed CO2 during early summer months when plants were growing, and emitted it later in the year, when plants decomposed. Methane was emitted throughout warm months, but week-to-week shifts in emissions were high, pointing to the need for frequent sampling for accurate accounting.

Part 1

Comment by Dr. Krishna Kumari Challa on Tuesday

Scientists Invented a Super-Slippery Toilet That Nothing Sticks to

The traditional porcelain and ceramic toilet bowls could be on the way out, if a new3D printed design from scientists  catches on – with the key benefit being the ultra slippery surface.

Poop that clings to the toilet bowl is not only unpleasant for bathroom visitors and cleaners alike, it actually wastes a significant amount of water as more flushes are required to dislodge the stuff.

It was this problem that the scientists wanted to tackle by making a non-stick toilet bowl. They used a mixture of plastic and hydrophobic sand grains for their material, fused together with laser-based 3D printing techniques, in a design that was around a tenth the size of a standard toilet bowl.

The abrasion-resistant super-slippery flush toilet, or ARSFT, was shown to repel synthetic feces, as well as multiple substances that the scientists tested. Nothing was able to get a grip on the surface, and everything slid straight down, much like the slippery pitcher plants that inspired the toilet design.

The as-prepared ARSFT remains clean after contacting with various liquids such as milk, yogurt, highly sticky honey, and starch gel mixed congee, demonstrating excellent repellence to complex fluids," write the researchers in their published paper.

https://onlinelibrary.wiley.com/doi/abs/10.1002/adem.202300703

Comment by Dr. Krishna Kumari Challa on Tuesday

Study finds significant chemical exposures in women with cancer

In a sign that exposure to certain endocrine-disrupting chemicals may be playing a role in cancers of the breast, ovary, skin and uterus, researchers have found that people who developed those cancers have significantly higher levels of these chemicals in their bodies.

While it does not prove that exposure to chemicals like PFAS (per- and poly-fluoroalkyl substances) and phenols (including BPA) led to these cancer diagnoses, it is a strong signal that they may be playing a role and should be studied further.

The study showed that particularly for women, higher exposure to PFDE, a long-chained PFAS compound, had double the odds of a previous melanoma diagnosis; women with higher exposure to two other long-chained PFAS compounds, PFNA and PFUA, had nearly double the odds of a prior melanoma diagnosis.

The study showed a link between PFNA and a prior diagnosis of uterine cancer; and women with higher exposure to phenols, such as BPA (used in plastics) and 2,5-dichlorophenol (a chemical used in dyes and found as a by-product in wastewater treatment), had higher odds of prior ovarian cancer diagnoses.

The study concludes that Since PFAS make up thousands of chemicals, one way to reduce exposures is for EPA to regulate PFAS as a class of chemicals, rather than one at a time.

Cathey, A.L et al, Exploratory profiles of phenols, parabens, and per- and poly-fluoralkyl substances among NHANES study participants in association with previous cancer diagnoses, Journal of Exposure Science & Environmental Epidemiology (2023). DOI: 10.1038/s41370-023-00601-6

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