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Comment by Dr. Krishna Kumari Challa on September 8, 2024 at 5:07pm

Scientists Discover Mosquitoes Are Using Infrared to Track Humans Down

There's something about us that mosquitoes just love. In addition to our smell, and our breath, our exposed skin acts as a kind of neon sign advertising that this blood bar is open for business.

That's because mosquitoes use infrared sensing in their antennae to track down their prey, a new study has found.
In many parts of the world, mosquito bites are more than an irritation, capable of spreading pathogens like dengue, yellow fever, and Zika virus. Malaria, spread by the Anopheles gambiae mosquito, caused more than 600,000 deaths in 2022, according to World Health Organization statistics.

To avoid serious disease, or even just a case of maddening itchiness, we humans are pretty keen to find ways to prevent mosquito bites.

Research found that mosquitoes use infrared detection – along with other cues we already knew about, like a nose for the CO2 in our breath, and certain body odours, to seek out hosts.

https://www.nature.com/articles/s41586-024-07848-5

Comment by Dr. Krishna Kumari Challa on September 8, 2024 at 4:16pm

Bacteria in your mouth Reproduce in a rare way

The microbial ecosystem nesting in your mouth is giving scientists a rare tool to learn about how bacteria multiply. One of the most common bacteria living in your dental plaque, a filamentous bacterium called Corynebacterium matruchotii, divides not into two daughter cells like most cell divisions but multiple new microbes in a rarer process called multiple fission.

A team of scientists observed single C. matruchotii cells dividing up into up to 14 new cells – a feat that can tell us how these organisms form the scaffolding that supports the hosts of other microbes that are dwelling in your mouth.

The Corynebacterium cells in dental plaque are like a big, bushy tree in the forest; they create a spatial structure that provides the habitat for many other species of bacteria around them.

Most bacteria and archaea reproduce via an asexual process called binary fission. The genetic material divides, and the cell itself then divides, resulting in two organisms where there was one.

Researchers saw the unusual cell division of C. matruchotii was not the normal binary kind, but much more prolific. And it does so in a very strange way.

First, the filament elongates at just one end, growing much longer than the usual size of the cell. It does so at a rate five times faster than other, closely related Corynebacterium species that live in the nose or on the skin.

Then, a number of dividing walls called septa form simultaneously, before the cell breaks apart into between 3 and 14 complete daughter cells.

Thanks to this strange process, a colony of C. matruchotii can grow very fast indeed, up to half a millimeter per day – which might help explain why plaque starts to return to your teeth within hours, no matter how strenuously you clean them.

Another interesting thing about C. matruchotii that might drive its strange growth and division is that it lacks a flagellum; the whip-like appendage other bacteria use to get around. Because it is fixed in place, its fast growth could be a means of exploring its environment and looking for sources of food, the researchers say.

https://www.pnas.org/doi/10.1073/pnas.2408654121

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 9:48am

Bat loss linked to death of human babies
When insect-eating bats are wiped out by ‘white nose syndrome’, farmers turn to pesticides for pest control — possibly leading to knock-on effects for human health. Researchers compared counties in the northeastern United States where the white nose fungus had killed most bats to those areas where the disease hadn’t yet spread. In places where bat populations had crashed, farmers used 31% more insecticides and infant deaths not due to accidents or homicides rose by 8% — numbers that the authors suggest might be linked. Where bats remained, there was no change in pesticide use or infant mortality.

The study is the “most convincing evidence to date” linking economic and health impacts with dramatic losses of a wild species.

Bats are good to have around a farm. They provide free pest control, with some species consuming 40% of their body weight each night in insects. The value of this service has been estimated at between $4 billion and $53 billion per year. So, it’s logical to assume farmers might compensate for a loss of bats by spraying more insecticides.

Infant mortality in all the counties: In places where the bat populations had crashed, deaths due to accident or homicides stayed the same. But other deaths, such as those caused by disease or birth defects, rose 8%. In counties with healthy bat populations, the numbers didn’t shift one way or another.

Several lines of evidence connect pesticides and other agrochemicals to human health risks.

That is why we say we - all living beings - are all dependent on one another for our survival.

https://www.science.org/doi/10.1126/science.adg0344

https://www.science.org/content/article/my-jaw-dropped-bat-loss-lin...

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 9:31am

Tidal Locking | Why Do We Only See One Side of the Moon?

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 8:51am

Study of older patients suggests 1 in 5 cases of dementia may be attributable to vision impairment

Prior research has found that there may be a connection between hearing loss in aging people and the onset of dementia. In a new study, a team of health care researchers and geriatric specialists  surveyed patient health care records and reported that approximately 1 in 5 cases of dementia could also be attributable to vision impairment in community-dwelling  adults aged 71 years or older.

The paper is published in the journal JAMA Ophthalmology.

Scientists still do not know what causes dementia, but they strongly suspect that it might be tied to several factors, one of which might be sensory degradation. As the senses lose their sharpness, the hypothesis proposes, the brain must work harder to make sense of the external environment, all while undergoing its own aging process.

The result could be loss of cognitive and memory abilities. In this new effort, the researchers looked for such evidence in people over the age of 71 who have experienced at least one of three main types of vision impairment: near or distance acuity, or contrast sensitivity.

They found that approximately 19% of dementia cases could be attributable to one or more types of vision loss. This, they note, suggests that dementia could have been prevented in nearly 20% of cases if loss of vision had been addressed. They note that prior studies have shown that approximately 90% of vision problems in older people are correctable through glasses or surgery.

The research team acknowledges that their results are based on associations rather than proof because there is no way to prove any single cause of dementia. But they also suggest that the associations they found make a strong case for it.

More information: Jason R. Smith et al, Vision Impairment and the Population Attributable Fraction of Dementia in Older Adults, JAMA Ophthalmology (2024). DOI: 10.1001/jamaophthalmol.2024.3131

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Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 8:27am

Researchers discover an effective and environment-friendly disinfectant

A widely used disinfectant worldwide, chloroxylenol, has been associated with eco-toxicological threats in water environments due to its relatively high chemical stability and massive consumption. Researchers at the School of Engineering of the Hong Kong University of Science and Technology (HKUST) have discovered a promising alternative known as 2,6-dichlorobenzoquinone (2,6-DCQ), which works more effectively in combating certain common bacteria, fungi and viruses, and can be rapidly degraded and detoxified in receiving waters.

Their findings have been published in Nature Communications.

Jiarui Han et al, An effective and rapidly degradable disinfectant from disinfection byproducts, Nature Communications (2024). DOI: 10.1038/s41467-024-48752-w

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 8:14am

Among the planets in the solar system, Earth is unique for having plate tectonics. Its rocky surface is split into fragments (plates) that grind into each other and create mountains, or split away and form chasms that are then filled with oceans.

Apart from causing earthquakes and volcanoes, plate tectonics also pushes up rocks from the deep earth into the heights of mountain ranges. This way, elements which were far underground can erode from the rocks and end up washing into rivers and oceans. From there, living things can make use of these elements.

Among these essential elements is phosphorus, which forms the framework of DNA molecules, and molybdenum, which is used by organisms to strip nitrogen out of the atmosphere and make proteins and amino acids—building blocks of life.

Plate tectonics also exposes rocks that react with carbon dioxide in the atmosphere. Rocks locking up carbon dioxide is the main control on Earth's climate over long time scales—much, much longer than the tumultuous climate change we are responsible for today.

Mapping the past plate tectonics of the planet is the first stage in being able to build a complete digital model of Earth through its history.

Xianzhi Cao et al, Earth's tectonic and plate boundary evolution over 1.8 billion years, Geoscience Frontiers (2024). DOI: 10.1016/j.gsf.2024.101922

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 8:13am

1.8 Billion Years of Plate Tectonics

Using information from inside the rocks on Earth's surface, researchers have reconstructed the plate tectonics of the planet over the last 1.8 billion years.

It is the first time Earth's geological record has been used like this, looking so far back in time. This has enabled us to make an attempt at mapping the planet over the last 40% of its history, which you can see in the animation below.

The work is now published in the open-access journal Geoscience Frontiers.

Mapping our planet through its long history creates a beautiful continental dance—mesmerizing in itself and a work of natural art.

It starts with the map of the world familiar to everyone. Then India rapidly moves south, followed by parts of Southeast Asia as the past continent of Gondwana forms in the Southern Hemisphere.

Around 200 million years ago (Ma or mega-annum in the reconstruction), when the dinosaurs walked the earth, Gondwana linked with North America, Europe and northern Asia to form a large supercontinent called Pangea.

Then, the reconstruction carries on back through time. Pangea and Gondwana were themselves formed from older plate collisions. As time rolls back, an earlier supercontinent called Rodinia appears. It doesn't stop here. Rodinia, in turn, is formed by the break-up of an even older supercontinent called Nuna about 1.35 billion years ago.

Part 1

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 8:07am

Researchers make sound waves travel in one direction only, with implications for electromagnetic wave technology

Researchers at ETH Zurich have managed to make sound waves travel only in one direction. In the future, this method could also be used in technical applications with electromagnetic waves.

Water, light and sound waves usually propagate in the same way forward as in a backward direction. As a consequence, when we are speaking to someone standing some distance away from us, that person can hear us as well as we can hear them. This is useful when having a conversation, but in some technical applications one would prefer the waves to be able to travel only in one direction—for instance, in order to avoid unwanted reflections of light or microwaves.

Ten years ago, researchers succeeded in suppressing sound wave propagation in the backward direction; however, this also attenuated the waves traveling forwards.

A team of researchers has now developed a method for preventing sound waves from traveling backward without deteriorating their propagation in the forward direction.

The basis of this one-way street for sound waves are self-oscillations, in which a dynamical system periodically repeats its behavior.

In the future, this method, which has recently been published in Nature Communications, could also be applied to electromagnetic waves.

Tiemo Pedergnana et al, Loss-compensated non-reciprocal scattering based on synchronization, Nature Communications (2024). DOI: 10.1038/s41467-024-51373-y

Part 2

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 7:58am

Low-cost nanomaterial technology can detect cancer genes with ultra-high sensitivity

A research team has  developed a technology that can detect cancer mutant genes in blood with the world's highest sensitivity of 0.000000001% based on plasmonic nanomaterials for optical signal amplification. The team tested blood samples from lung cancer patients (stages 1-4) and healthy individuals for EGFR mutations and achieved a diagnostic accuracy of 96%.

The work is published in the journal Small Science.

Previously utilized genetic analysis technologies had low analytical sensitivity to detect mutated genes compared to normal genes, making it difficult to accurately diagnose early-stage cancer patients. In addition, it was difficult to establish a quick treatment strategy and apply it to screening tests due to the high cost and long time required for analysis and the need for special equipment.

To overcome these challenges, the research team developed a low-cost analysis technology that can analyze various cancer mutations within the target gene region within one hour with an ultra-high sensitivity of 0.000000001%. This technology boasts the world's highest level of sensitivity, which is 100,000 times better than the highest level of 0.0001% among reported technologies, and through this, the possibility of early diagnosis was confirmed using the blood of lung cancer patients.

This technology combines nanomaterial technology that significantly improves the fluorescence signal, and primer/probe design that suppresses the fluorescence signal of normal genes, amplifying only the fluorescence signal of cancer mutant genes. This is because the accurate detection of even very small amounts of cancer mutated genes requires not only strong fluorescent signal expression technology but also precise discrimination of fine fluorescent signals.

The team fabricated a biochip in the form of a microarray capable of simultaneously detecting three mutant genes of EGFR (deletion, insertion, and point mutations) on a plasmonic substrate made of three-dimensional, high-density gold nanostructures. After evaluating the clinical performance of 43 domestic lung cancer patients (stages 1 to 4) and 40 normal groups, a clinical sensitivity of 93% for lung cancer patients and a clinical specificity of 100% for the normal group were confirmed.

This technology can play an important role in not only early diagnosis and detection of recurrence of cancer, but also in monitoring treatment effectiveness and establishing personalized treatment plans. In addition, liquid biopsy using blood is possible as an alternative to surgical tissue biopsy, reducing the burden on patients and simplifying the examination process. It can also serve as a regular screening test, ultimately improving the quality of cancer management and treatment.

Ji Young Lee et al, Highly Sensitive 3D‐Nanoplasmonic‐Based Epidermal Growth Factor Receptor Mutation Multiplex Assay Chip for Liquid Biopsy, Small Science (2024). DOI: 10.1002/smsc.202400101

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