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Comment by Dr. Krishna Kumari Challa on August 17, 2021 at 10:52am

Wildfire smoke can reduce raindrops to meaningless drizzle, study says. Here's how

When wildfires burn, they catapult smoke into the atmosphere. These plumes are loaded with tiny particles that act as magnets for water droplets sitting in clouds—the more smoky particles ejected into the sky, the more rain comes down.

So, researchers assumed that more wildfires equal more rainfall. But a new study flipped those assumptions upside down. Turns out, the murky relationship between wildfire smoke and cloud formation only holds true for clouds high in the atmosphere.

For those closer to the ground, the mingling of smoky particles may actually make it less likely that rain will fall, triggering a cascade of reactions that fuel instead of calm fire activity on land.

They found that clouds hovering above wildfires contained about five times the number of droplets than clouds free of smoky particles, yet the droplets were half the size of those in their "clean" counterparts.

This unexpected size difference, researchers say, is what could determine if we will experience a downpour or a meaningless drizzle.

Cynthia H. Twohy et al, Biomass Burning Smoke and Its Influence on Clouds Over the Western U. S., Geophysical Research Letters (2021). DOI: 10.1029/2021GL094224

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Smaller droplets are less likely to grow into heavier ones that will eventually fall as rain, meaning wildfire seasons could be exacerbated by drier conditions on land that ultimately fuel more and larger blazes.

https://phys.org/news/2021-08-wildfire-raindrops-meaningless-drizzl...

Comment by Dr. Krishna Kumari Challa on August 17, 2021 at 10:42am

How jet streams affect our weather: an in-depth guide

Comment by Dr. Krishna Kumari Challa on August 17, 2021 at 10:14am

Fighting fungal infections with smart nanotech

Newly engineered nanoparticles the size of coronavirus  developed by scientists are punching well above their weight when it comes to treating drug-resistant fungal infections.

They have  a remarkable ability to battle one of the most invasive and notoriously resistant fungal infections—Candida albicans. Micelles are made of lipid molecules that arrange themselves in a spherical form in aqueous solutions. They both attract and repel liquids, making them particularly well suited for drug delivery.

Candida albicans is an opportunistic pathogenic yeast that is extremely dangerous to people with compromised immune systems, particularly those in a hospital setting. Found on many surfaces, Candida albicans is notorious for its resilience to anti-fungal medicines. It is the most prevalent cause of fungal infections worldwide and can cause serious infections that can affect the blood, heart, brain, eyes, bones, and other parts of the body.

The new polymer-based micelles could revolutionize current anti-fungal medicines.

Fungal biofilms are surface-loving microbials that thrive on implanted devices such as catheters, prostheses and heart valves, making the presence of these devices a major risk factor for infection.

"In places like India—which has nearly 40,000 new COVID-19 infections every day—hospital resources are severely stretched, leaving healthcare workers are not only battling COVID-19, but also dealing with complacency and fatigue.

"The unfortunate result is that infection control practices have deteriorated, putting patients on mechanical ventilation at greater risk of developing bacterial or fungal infections.

"As fungal biofilms tend to seed recurrent infections, finding ways to break and beat the infection cycle is critical, especially now. 

smart micelles that have the ability to break down single and multi-species biofilms to significantly inhibit the growth of Candida albicans, one of the most virulent fungal species.

Researchers estimate that the new micelles could improve the efficacy of anti-fungal medicines by 100-fold, potentially saving the lives of millions of people worldwide. 

These micelles have a unique ability to solubilize and entrap a range of important antifungal drugs to significantly improve their performance and efficacy."

This is the first time that polymer-based micelles have been created with intrinsic capabilities to prevent fungal biofilm formation.

The new micelles will remove up to 70 percent of infection, this could be a real game changer for treating fungal diseases.

 Yassamin N. Albayaty et al, Polymeric micelles with anti-virulence activity against Candida albicans in a single- and dual-species biofilm, Drug Delivery and Translational Research (2021). DOI: 10.1007/s13346-021-00943-4

Yassamin N. Albayaty et al, pH-Responsive copolymer micelles to enhance itraconazole efficacy against Candida albicans biofilms, Journal of Materials Chemistry B (2020). DOI: 10.1039/C9TB02586C

https://phys.org/news/2021-08-fungal-infections-giant-smart-nanotec...

Comment by Dr. Krishna Kumari Challa on August 17, 2021 at 9:58am

Pollinators: First global risk index for species declines and effects on humanity

Disappearing habitats and use of pesticides are driving the loss of pollinator species around the world, posing a threat to "ecosystem services" that provide food and wellbeing to many millions—particularly in the Global South—as well as billions of dollars in crop productivity.

This is according to an international panel of experts, led by the University of Cambridge, who used available evidence to create the first planetary risk index of the causes and effects of dramatic pollinator declines in six global regions.

The bees, butterflies, wasps, beetles, bats, flies and hummingbirds that distribute pollen, vital for the reproduction of over 75% of  food crops and flowering plants—including coffee, rapeseed and most fruits—are visibly diminishing the world over, yet little is known of the consequences for human populations.

What happens to pollinators could have huge knock-on effects for humanity. These small creatures play central roles in the world's ecosystems, including many that humans and other animals rely on for nutrition. If they go, we may be in serious trouble.

The top three global causes of pollinator loss are habitat destruction, followed by land management—primarily the grazing, fertilizers and crop monoculture of farming—and then widespread pesticide use, according to the study. The effect of climate change comes in at number four, although data are limited.

Perhaps the biggest direct risk to humans across all regions is "crop pollination deficit": falls in quantity and quality of food and biofuel crops. Experts ranked the risk of crop yield "instability" as serious or high across two-thirds of the planet—from Africa to Latin America—where many rely directly on pollinated crops through small-holder farming.

Increasingly unusual climatic phenomena, such as extreme rainfall and temperature, are already affecting crops. Pollinator loss adds further instability.

A global-scale expert assessment of drivers and risks associated with pollinator decline, Nature Ecology & Evolution (2021). DOI: 10.1038/s41559-021-01534-9 , www.nature.com/articles/s41559-021-01534-9

https://phys.org/news/2021-08-pollinators-global-index-species-decl...

Comment by Dr. Krishna Kumari Challa on August 16, 2021 at 10:30am

Deforestation Can Cause Rapid Evolutionary Changes in Insects

People in New Zealand have cut down so many trees, some native insects are losing their wings.

In the space of 750 years, humans have changed the natural landscape of the country's South Island so much, scientists say it's causing rapid evolutionary changes among certain species.

With no more alpine forest to break the strong mountaintop winds, at least one type of insect is already transitioning out of the flight industry.

Zelandoperla fenestrata is a stonefly with two distinct phenotypes: one with wings, capable of flight; and one with stunted wings or even none, described as flightless.

The flightless type of stonefly is usually found at higher altitudes, where trees are scarce and strong winds can therefore easily blow a flying insect out into the abyss. Meanwhile, the flight-capable flies are typically sheltered in alpine forests, where insects need to explore the full extent of the habitat.

However, in regions where alpine forests have been cut down, researchers have noticed something intriguing. The insects at this elevation, which should usually be able to fly, can't do so.

It appears that human-caused deforestation has indirectly deprived these insects of their ability to fly, and we did so in a very short span of time.

In addition to the local shifts inferred here, it is likely that widespread deforestation has increased the proportion of flightless lineages across large areas of southern New Zealand.

The researchers worry  that without wings, stoneflies won't be able to search for mates in a larger territorial range, thus increasing genetic diversity. This could possibly impact the species' health in the long run, as well as the insects' risk of extinction.

https://royalsocietypublishing.org/doi/10.1098/rsbl.2021.0069

Comment by Dr. Krishna Kumari Challa on August 15, 2021 at 7:58am

Can "squirrelly" skills be built into robots?

Comment by Dr. Krishna Kumari Challa on August 15, 2021 at 7:38am

Our Metabolism Changes With Age, But It's Not When You Think

Metabolism – the rate that we burn calories to keep our bodies running – changes as we age.

A new study looking at metabolism across the generations has come up with some rather surprising findings.

The researchers were able to pull in a huge amount of data from 6,421 people across 29 countries and with an age range of 8 days old to 95 years old. By using isotopes placed in drinking water and then tracked through urine, researchers worked out a daily energy expenditure figure for each participant.

Contrary to popular belief, pound-for-pound our metabolic rate peaks when we're infants. So, when we're teenagers, we're only burning calories at a slighter faster rate than when we're middle-aged.

The thickening waistlines associated with middle age might not all be down to a slow metabolic rate, in other words.

As young people, our metabolisms seem to slow down by about 3 percent until our 20s, when they level off, the data showed – there's no real spurt over puberty. During our 20s through to our 50s, that's when our metabolic rate seems to be the most stable.

Once we hit our 60s, researchers found that our metabolisms seem to slow down by about 0.7 percent a year. By the time a person reaches their 90s, on average they need 26 percent fewer calories for energy per day than someone who's middle-aged – not just because of less muscle mass, but because their cells are slowing down.

But it's during the first 12 months of life that energy needs really shift. A 1-year-old burns calories around 50 percent faster for their body size than an adult. Even controlling for rapid increases in weight, energy use is "rocketing" in these early months, according to researchers.

The findings could be useful is in tailoring health treatments to specific people and specific age ranges, taking shifts in metabolism into account.

https://science.sciencemag.org/content/373/6556/808

Comment by Dr. Krishna Kumari Challa on August 14, 2021 at 9:38am

Scientists show how blocking opioid receptors in specific neurons can restore breathing during an overdose

Opioid overdose deaths are caused by disrupted breathing, but the actual mechanism by which these drugs suppress respiration was not understood. Now, a new study by  scientists has identified a group of neurons in the brainstem that plays a key role in this process.

The new findings show how triggering specific receptors in these neurons causes opioid-induced respiratory depression, or OIRD, the disrupted breathing that causes overdose deaths. It also shows how blocking these receptors can cause OIRD to be reversed.

Opioids work by binding to proteins on nerve cells (neurons) called opioid receptors and subsequently inhibiting their activity. Currently, naloxone is the only medication known to block the effects of opioids and reverse an overdose. But naloxone has limitations, including a short duration that requires it to be administered multiple times. It also works systemically, blocking opioid receptors throughout the entire body, including those that control pain.

In the new study, the researchers identified a group of neurons that express a certain type of opioid receptor (the mu opoid receptor) and are located in the brainstem breathing modulation center; they then characterized these neurons' role in OIRD.

They found that mice that were genetically engineered to lack opioid receptors in these neurons didn't have their breathing disrupted when exposed to morphine, as mice in the control group did. The researchers also found that, without introducing opioids, stimulating these receptors in control mice caused symptoms of OIRD.

The team then looked at ways to reverse the process by treating the overdosed mice with chemical compounds targeted to other receptors on the same neurons, which play an opposite role as the opioid receptor (activating rather than inhibiting them).

Shijia Liu et al, Neural basis of opioid-induced respiratory depression and its rescue, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2022134118

https://medicalxpress.com/news/2021-08-scientists-blocking-opioid-r...

Comment by Dr. Krishna Kumari Challa on August 13, 2021 at 7:42am

Antibodies Stop Sperm in Their Tracks

Engineered antibodies trap and immobilize human sperm in the reproductive tract of female sheep, paving the way for possible use as a nonhormonal contraceptive in people.

Currently, most available birth control options are barrier methods or rely on hormones to prevent fertilization of an egg—both of which have drawbacks, such as discomfort or side effects, that make them less than ideal for some people. Enter antisperm antibodies, described in a study published today (August 11) in Science Translational Medicine. Researchers generated antibodies that recognize an antigen unique to human sperm. When delivered topically to the reproductive tracts of sheep, the antibodies successfully bound and trapped more than 99.9 percent of introduced human sperm. Some of the authors have spun out a company, Mucommune, in order to continue the development of contraceptives based on these antibodies.

Previous work showed that some women’s bodies naturally produce antibodies to sperm that can lead to a type of immunological infertility. Lai’s group used the antigen binding fragment from one of these antibodies, which recognizes a sperm-specific antigen known as CD52g, in a study published in 2020, where they engineered an IgG antibody with four of the antigen-binding fragments and showed that it and the original, naturally-occurring IgG antibody with two antigen binding domains trapped sperm in vitro. 

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In the new study, Lai and colleagues added multiple antigen-binding fragments—6, 8, or 10—to an IgG antibody and then introduced expression plasmids into human embryonic kidney cells so the cells would produce them and researchers could isolate them. The team tested the antibodies’ ability to immobilize sperm in vitro, where the antibodies with extra antigen-binding fragments trapped sperm at least 10 times more effectively than the original IgG antibody with just two antigen-binding fragments. 

To explore the effects of the antibodies in vivo, the researchers introduced the original IgG antibody, one with 6 or 10 antigen-binding fragments, or saline into the vaginas of female sheep, which are similar to the human female reproductive tract, and then simulated intercourse and delivered a human semen sample. Two minutes later, they retrieved the sample and analyzed sperm movement. At a high dose (333 micrograms of antibody), all three antibodies tamped down nearly all sperm motility, and at a low dose (33.3 micrograms), both modified antibodies, but not the original IgG, trapped more than 90 percent of sperm.

https://stm.sciencemag.org/content/13/606/eabd5219

https://www.the-scientist.com/news-opinion/antibodies-stop-sperm-in...

Comment by Dr. Krishna Kumari Challa on August 13, 2021 at 7:10am

Newtonian physics for babies

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