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Comment by Dr. Krishna Kumari Challa on November 3, 2022 at 9:06am

 Groundbreaking bioelectronic devices: Bacterial sensors send a jolt of electricity when triggered

When you hit your finger with a hammer, you feel the pain immediately. And you react immediately. But what if the pain comes 20 minutes after the hit? By then, the injury might be harder to heal.

The same is true for the environment. If a chemical spill in a river goes unnoticed for 20 minutes, it might be too late to remediate.

Scientists thought living bioelectronic sensors can help. So they engineered bacteria to quickly sense and report on the presence of a variety of contaminants.

The study published in Nature journal shows the cells can be programmed to identify chemical invaders and report within minutes by releasing a detectable electrical current.

Such "smart" devices could power themselves by scavenging energy in the environment as they monitor conditions in settings like rivers, farms, industry and waste water treatment plants and to ensure water security, according to the researchers.

The researchers' proof-of-concept bacteria was Escherichia coli, and their first target was thiosulfate, a dichlorination agent used in water treatment that can cause algae blooms.

 Caroline Ajo-Franklin, Real-time bioelectronic sensing of environmental contaminants, Nature (2022). DOI: 10.1038/s41586-022-05356-y. www.nature.com/articles/s41586-022-05356-y

The environmental information communicated by these self-replicating bacteria can be customized by replacing a single protein in the eight-component, synthetic electron transport chain that gives rise to the sensor signal.

Comment by Dr. Krishna Kumari Challa on November 2, 2022 at 12:09pm

Neurotransmitter Buildup May Be Why Your Brain Feels Tired

Performing complex cognitive tasks leads to glutamate accumulating in a key region of the brain, a study finds, which could explain why mental labor is so exhausting.

The fatigue that comes from performing demanding mental tasks may stem from a buildup of the neurotransmitter glutamate, according to research published recently in Current Biology.

Mental fatigue also appears to shift decision-making toward a kind of easy-button mode where the brain favours low-cost, immediate-reward options, according to researchers. So after a day of work, you [make] different choices compared to when you’re fresh in the morning. They think that this is due to glutamate accumulation.

The research has identified a potential marker of fatigue to study more widely in athletes or in people with disorders such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). 

Previous theories posited that the tiredness people experience from mental exertion stemmed from the depletion of energy reserves. But research hasn’t borne that out, the study authors write. 

The region that helps orchestrate cognitive control: the left lateral prefrontal cortex.  In addition to helping us undertake complex tasks like solving a Sudoku puzzle, playing chess, or designing an experiment, the left lateral cortex helps control the processes required to remember and manipulate information to solve those problems. It’s also part of the system that says, ‘Well, actually, maybe I don’t want to play chess. I want to watch Netflix and do something simpler. I want to relax.

That result of this work suggested to the researchers that mental fatigue could be the result of the glutamate diffusing out of neurons and building up this area of the brain, perhaps causing it to work less efficiently. 

https://www.cell.com/current-biology/fulltext/S0960-9822(22)01111-3

Comment by Dr. Krishna Kumari Challa on November 2, 2022 at 9:47am

Photos suggest rhino horns have shrunk over past century, likely due to hunting

By scrutinizing over a century's worth of photos researchers have made the first ever measurements that show rhinoceros horns have gradually decreased in size over time.

The researchers measured the horns of 80 rhinos, photographed in profile view between 1886 and 2018. The photographs, held by the Rhino Resource Center—an online repository—included all five species of rhino: white, black, Indian, Javan and Sumatran. Horn length was found to have decreased significantly in all species over the last century.

Real rhino horns are so valuable that strict security protocols typically prevent researchers accessing them for study, so this is the first time that horn length has been measured over a long timeframe.

The researchers think rhino horns have become smaller over time due to intensive hunting. Rhino horns command a high price and are in demand both as a financial investment, and for their use in traditional medicines in China and Vietnam. The report is published today in the journal People and Nature.

Image-based analyses from an online repository provide rich information on long-term changes in morphology and human perceptions of rhinos, People and Nature (2022). DOI: 10.1002/pan3.10406

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Comment by Dr. Krishna Kumari Challa on November 2, 2022 at 9:43am

Monoclonal antibody prevents malaria infection

One dose of an antibody drug safely protected healthy, non-pregnant adults from malaria infection during an intense six-month malaria season in Mali, Africa, a National Institutes of Health clinical trial has found. The antibody was up to 88.2% effective at preventing infection over a 24-week period, demonstrating for the first time that a monoclonal antibody can prevent malaria infection in an endemic region. 

These study results suggest that a monoclonal antibody could potentially complement other measures to protect travelers and vulnerable groups such as infants, children, and pregnant women from seasonal malaria and help eliminate malaria from defined geographical areas.

Malaria is caused by Plasmodium parasites, which are transmitted to people through the bite of an infected mosquito. The mosquito injects the parasites in a form called sporozoites into the skin and bloodstream. These travel to the liver, where they mature and multiply. Then the mature parasite spreads throughout the body via the bloodstream to cause illness. P. falciparum is the Plasmodium species most likely to result in severe malaria infections, which—if not promptly treated—may lead to death.

The Phase 2 NIAID-USTTB trial evaluated the safety and efficacy of a one-time, intravenous infusion of a monoclonal antibody called CIS43LS. This antibody was previously shown to neutralize the sporozoites of P. falciparum in the skin and blood before they could infect liver cells. Researchers  isolated a naturally occurring form of this antibody from the blood of a volunteer who had received an investigational malaria vaccine, and then modified the antibody to extend the length of time it would remain in the bloodstream. And tested it.

  Kassoum Kayentao. Testing the safety and efficacy of anti-malaria monoclonal antibodies in African adults and children. Session 41—Progress in the discovery and clinical development of anti-malaria monoclonal antibodies. ASTMH 2022 Annual Meeting, Seattle. Monday, Oct. 31, 2022. 5:40 pm Pacific Time.

Kassoum Kayentao et al, Safety and efficacy of a monoclonal antibody against malaria in Mali. The New England Journal of Medicine DOI: 10.1056/NEJMoa2206966 (2022).

R.L. Wu et al, Low-dose subcutaneous or intravenous monoclonal antibody to prevent malaria. The New England Journal of Medicine DOI: 10.1056/NEJMoa2203067 (2022).

Comment by Dr. Krishna Kumari Challa on November 1, 2022 at 9:27am

Should we move species to save them?

A proposed change to conservation rules in the United States could expand the use of a controversial tool to save species on the.... Assisted migration, in which an endangered species is relocated to a new environment, is a last resort for organisms being squeezed out of their historic ranges by climate change, habitat loss and threats from introduced species. But fears of unintended ecological consequences have limited its use so far. The US Fish and Wildlife Service is set to relax assisted-migration regulations, to allow experimental relocations outside a species’ current or recent range. Regulators “need to seriously consider conservation actions that are currently deemed too extreme”, says conservation biologist Avril Harder.

Comment by Dr. Krishna Kumari Challa on November 1, 2022 at 9:24am

Geomagnetic fields reveal the truth behind Biblical narratives

A joint study by TAU and the Hebrew University, involving 20 researchers from different countries and disciplines, has accurately dated 21 destruction layers at 17 archaeological sites in Israel by reconstructing the direction and/or intensity of the earth's magnetic field recorded in burnt remnants. The new data verify the Biblical accounts of the Egyptian, Aramean, Assyrian, and Babylonian military campaigns against the Kingdoms of Israel and Judah.

Comment by Dr. Krishna Kumari Challa on November 1, 2022 at 8:59am

Rainbows will change their frequency because of climate change

Climate change will increase or decrease opportunities to see rainbows, according to a new study led by researchers.

The study's authors estimate that by 2100, the average land location on Earth will experience about 5% more days with rainbows than at the beginning of the 21st century.

Northern latitudes and very high elevations, where warming is predicted to lead to less snow and more rain, will experience the greatest gains in rainbow occurrence. However, places with reduced rainfall under climate change—such as the Mediterranean—are projected to lose rainbow days.

Rainbows are produced when water droplets refract sunlight. Sunlight and rainfall are therefore essential ingredients for rainbows. Human activities such as burning fossil fuels are warming the atmosphere, which changes patterns and amounts of rainfall and cloud cover.

Researchers  sorted through tens of thousands of photos taken around the world, labeled with the word "rainbow," to identify rainbows generated from the refraction of light by rain droplets.

Then, the scientists trained a rainbow prediction model based on rainbow photo locations and maps of precipitation, cloud cover, and sun angle. Finally, they applied their model to predict present day and future rainbow occurrences over global land areas. The model suggests that islands are rainbow hotspots.

Kimberly M. Carlson et al, Global rainbow distribution under current and future climates, Global Environmental Change (2022). DOI: 10.1016/j.gloenvcha.2022.102604

Comment by Dr. Krishna Kumari Challa on October 31, 2022 at 11:37am

Physicists see light waves moving through a metal

When we encounter metals in our day-to-day lives, we perceive them as shiny. That's because common metallic materials are reflective at visible light wavelengths and will bounce back any light that strikes them. While metals are well suited to conducting electricity and heat, they aren't typically thought of as a means to conduct light.

But in the burgeoning field of quantum materials, researchers are increasingly finding examples that challenge expectations about how things should behave. In new research published in Science Advances, a research team describes a metal capable of conducting light. These results defy our daily experiences and common conceptions.

Researchers have been  exploring the optical properties of a semimetal material known as ZrSiSe. They  showed that ZrSiSe shares electronic similarities with graphene, the first so-called Dirac material discovered in 2004. ZrSiSe, however, has enhanced electronic correlations that are rare for Dirac semimetals.

Whereas graphene is a single, atom-thin layer of carbon, ZrSiSe is a three-dimensional metallic crystal made up of layers that behave differently in the in-plane and out-of-plane directions, a property known as anisotropy. It's sort of like a sandwich: One layer acts like a metal while the next layer acts like an insulator. Whereas graphene is a single, atom-thin layer of carbon, ZrSiSe is a three-dimensional metallic crystal made up of layers that behave differently in the in-plane and out-of-plane directions, a property known as anisotropy. "It's sort of like a sandwich: One layer acts like a metal while the next layer acts like an insulator.

They observed such zigzag movement of light, so-called hyperbolic waveguide modes, through ZrSiSe samples of varying thicknesses. Such waveguides can guide light through a material and here, result from photons of light mixing with electron oscillations to create hybrid quasiparticles called plasmons.

Although the conditions to generate plasmons that can propagate hyperbolically are met in many layered metals, it is the unique range of electron energy levels, called electronic band structure, of ZrSiSe that allowed the team to observe them in this material.

Yinming Shao et al. Infrared plasmons propagate through a hyperbolic nodal metal. Science Advances (2022). DOI: 10.1126/sciadv.add6169

Comment by Dr. Krishna Kumari Challa on October 29, 2022 at 8:38am

Heat waves driven by climate change have cost global economy trillions since the 1990s

Massive economic losses due to sweltering temperatures brought on by human-caused climate change are not just a problem for the distant future. A study in the journal Science Advances has found that more severe heat waves resulting from global warming have already cost the world economy trillions of dollars since the early 1990s—with the world's poorest and lowest carbon-emitting nations suffering the most.

Researchers combined newly available, in-depth economic data for regions worldwide with the average temperature for the hottest five-day period—a commonly used measurement of heat intensity—for each region in each year. They found that from 1992–2013, heat waves statistically coincided with variations in economic growth and that an estimated $16 trillion was lost to the effects of high temperatures on human health, productivity and agricultural output.

The findings stress the immediate need for policies and technologies that protect people during the hottest days of the year, particularly in the world's warmest, most economically vulnerable nations, the researchers report.

Christopher W. Callahan et al, Globally unequal effect of extreme heat on economic growth, Science Advances (2022). DOI: 10.1126/sciadv.add3726. www.science.org/doi/10.1126/sciadv.add3726

Comment by Dr. Krishna Kumari Challa on October 29, 2022 at 7:01am

The study also shows remarkable similarities, or convergence, among placental mammals with most mammal skull shapes evolving in much the same way throughout the fossil record. The biggest exceptions are whales and rodents.

What makes mammals evolve fast?

A key aim of this study is to better predict how different species may respond to rapid changes in their environment—the kind we are likely to see throughout the current planetary emergency. To do this the team investigated the characteristics of mammals that evolve fast and found the key influencers to be habitat, social behaviors, diet, parental care and time of activity.

Social structures hugely differentiate the rate which mammals evolve. Mammals which are social evolve much faster than those that are solitary. This is easily witnessed in ungulates which have evolved horns and antlers for fighting and social display. Mammals that live in aquatic environments, including whales but also manatees, seals and walruses are also fast evolvers. Herbivores also evolve faster than carnivores, probably because they track changes in plants and the environment more closely than meat eaters do.

Parental care also seems to be a big factor slowing down the speed of evolution. Precocial animals that require little primary care, such as horses and antelopes, evolve a lot faster than altricial mammals that are reliant on caregivers in infancy, such as primates. When animals are active also makes a difference, with species with a strict schedule, whether nocturnal or diurnal, evolving slower than animals without a fixed activity pattern.

Unexpectedly, the groups of mammals with the most species, rodents and bats, don't appear to evolve very quickly, suggesting that diversity in shape and diversity in number aren't closely linked in mammals.

Anjali Goswami et al, Attenuated evolution of mammals through the Cenozoic, Science (2022). DOI: 10.1126/science.abm7525

Part 2

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