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Comment by Dr. Krishna Kumari Challa on February 8, 2024 at 6:37am

Can an experimental cell phone app screen coughs for TB? Scientists say 'yes'

What telltale features—many inaudible to the human ear—separate one kind of cough from another? Scientists are on the verge of finding out with a new machine learning tool aimed at identifying the signature sounds of tuberculosis.

Cough is a leading symptom of respiratory infections. And because the pattern and frequency of cough episodes differ from one disease to the next, an effort is underway to develop a smartphone app that is sensitive enough to accurately discern coughs associated with TB.

An international team of researchers is testing the hypothesis that TB's unique pattern and frequency of coughing can provide sufficient data to screen for the highly infectious bacterial disease using technology engineered into a smartphone app.

Currently in the investigational phase, the app is not yet ready for distribution. At present it is a machine-learning tool called TBscreen, but given the rising numbers of TB cases around the globe, its development couldn't have arrived at a more opportune time.

The research team includes engineers and computer scientists as well as physicians and experts in infectious diseases.

When they entered audio of coughs through various microphones into TBscreen, the team found that TBscreen—the investigational app—and a smartphone mic identified active TB more accurately than when cough audio was fed through expensive microphones.

The machine-learning tool is being "trained" to recognize pattern and frequency in coughs caused by TB. The investigational app also is being trained to distinguish TB-related coughs from those caused by other respiratory disorders.

Researchers have found that there are numerous factors affecting the basic patterns of coughing, nuances—some inaudible to the human ear—that the tool must discern as a way to accurately screen for TB.

The mechanism of cough production varies according to mucus properties, respiratory muscle strength, mechanosensitivity, chemosensitivity of airways, and other factors resulting in diverse cough sounds.

Manuja Sharma et al, TBscreen: A passive cough classifier for tuberculosis screening with a controlled dataset, Science Advances (2024). DOI: 10.1126/sciadv.adi0282

Comment by Dr. Krishna Kumari Challa on February 8, 2024 at 6:31am

Study finds that microglia could regulate sleep via the modulation of norepinephrine transmission

Sleep is known to play a key role in facilitating various physiological processes, while also contributing to the healthy functioning of the brain. Lack of sleep and poor sleep quality have been linked to various chronic health and mental health issues, including high blood pressure, depression, stroke, obesity, and heart disease.

Sleep disturbances have also been implicated in the development of neurodegenerative diseases. Interestingly, neurodegenerative diseases have also been associated with the dysfunction of microglia, the primary mammalian immune cells, yet the link between microglia and sleep has not been thoroughly studied yet.

Researchers recently carried out a study exploring the potential role of microglia in regulating sleep. Their findings, published in Nature Neuroscience, suggest that microglia regulate sleep by modulating the transmission of the neurotransmitter norepinephrine, which is known to contribute to arousal, attention and stress reactions.

These initial observations could soon pave the way for further studies investigating the role of microglia in sleep regulation, focusing on norepinephrine transmission.

As microglia dysfunction and sleep disturbances have been linked to Alzheimer's and other neurodegenerative diseases, this work may also broaden neuroscientists' understanding of these diseases, potentially aiding the future development of new therapeutic strategies.

 Chenyan Ma et al, Microglia regulate sleep through calcium-dependent modulation of norepinephrine transmission, Nature Neuroscience (2024). DOI: 10.1038/s41593-023-01548-5.

Comment by Dr. Krishna Kumari Challa on February 7, 2024 at 9:05am

The team says they weren't expecting this evolution and decrease in metabolic coupling, and it's far from clear as to why these changes occur in the way they do.

But it's easy to see why they think this drastic reprogramming could go awry, perhaps leading to some of the metabolic conditions that arise during pregnancy. The roles of all 91 pregnancy-adaptive metabolites were verified in human cell models and in 32 pregnant human's blood serum samples.

Those pregnant women with pre-eclampsia – a dangerous natal condition characterized by high blood pressure, severe swelling, and protein-laden urine – had a huge drop in levels of the metabolite corticosterone, which is involved in maturing the placenta.

Another key metabolite during pregnancy appears to be palmitoylcarnitine, which regulates immunity and is involved in processing fatty acids. Levels were up in the tissues of early- and mid-pregnant monkeys, across a range of organs including the liver, pancreas, heart, and kidney.

The researchers think that this metabolic shift may have some link to gestational diabetes, but more research is needed to confirm this. 

This research was published in Cell.

https://www.cell.com/cell/fulltext/S0092-8674(23)01329-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867423013296%3Fshowall%3Dtrue

Part 3

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Comment by Dr. Krishna Kumari Challa on February 7, 2024 at 9:03am

The samples from the non-pregnant monkeys provided a reference point for how certain metabolic pathways interact prior to pregnancy, with the other samples revealing the drastic extent to which these 'trade routes' changed course as the monkey's pregnancies progressed.

In fact, during pregnancy, 91 metabolites changed consistently across all 23 tissues sampled.

In non-pregnant monkeys, the metabolomes of skeletal muscles were highly correlated with tissues from the heart, spinal cord, adrenal gland, and uterus. But in the first and second trimesters, their coupling with heart tissues decreased.

In early pregnancy, the samples indicated that the uterus backs off from its ongoing metabolic 'agreement' with the heart and skeletal muscles, coupling with the developing placenta instead.

Fully formed by the second trimester, the placenta appeared to be sending metabolites to the pregnant monkey's heart, ovaries, and liver. Weirdly, the uterus, seemingly done with getting the placenta established, shifts its focus to a metabolic exchange with scalp skin tissue, of all things.

And for those monkeys in their third trimester, the samples showed the skeletal muscles had developed a significant exchange with the spinal cord.
Part 2

Comment by Dr. Krishna Kumari Challa on February 7, 2024 at 9:03am

Monkey Study Reveals 91 Changes in Virtually Every Body Organ During Pregnancy

Scientists have mapped out the drastic changes pregnancy makes to the body's metabolic pathways in a closely related primate, and it could guide the way to better understanding pregnancy problems like recurrent miscarriage, pre-eclampsia, and gestational diabetes.

Little is known about this major disruption to the body's metabolic flow, but now a team of biologists from the Chinese Academy of Sciences in Beijing has studied crab-eating macaques (Macaca fascicularis) to create a map that charts at least some of the changes that occur during pregnancy.
These monkeys are one of the primates most closely related to humans, so they're often used as a proxy in experiments that can't be done on humans.

The researchers collected 273 tissue samples from 12 captive-bred monkeys – three each that were not pregnant, in early pregnancy (5–8 weeks), in mid-pregnancy (12–15 weeks) and in late pregnancy (18–20 weeks).

This included a blood serum sample taken from each monkey before they were euthanized, when a further 22 tissue samples were collected from different body systems, including the uterus, liver, spinal cord, skin, blood, and five different heart regions.

The metabolism is made up of thousands of different chemical pathways, like a bustling port city where a log of imports and exports wouldn't suffice to capture the complex ecosystem of logistics.

It's business as usual for the myriad cells, tissues, and organs that trade the raw materials of life until, as always, a baby comes along and changes everything.

The researchers were able to identify the full set of small-molecule chemicals within each sample, which is known as a 'metabolome'.

Part 1

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

There's just one problem: alkali metals are highly reactive with liquid water, sometimes even to the point of explosivity.

The research team found a very nifty way to solve this problem. What if, rather than adding the metal to water, water was added to the metal?

In a vacuum chamber, the team started by extruding from a nozzle a small blob of sodium-potassium alloy, which is liquid at room temperature, and very carefully added a thin film of pure water using vapor deposition.

Upon contact, the electrons and metal cations (positively charged ions) flowed into the water from the alloy.

Not only did this give the water a golden shine, it turned the water conductive – just like we should see in metallic pure water at high pressure.

This was confirmed using optical reflection spectroscopy and synchrotron X-ray photoelectron spectroscopy. The two properties – the golden sheen and the conductive band – occupied two different frequency ranges, which allowed them both to be identified clearly.

https://www.nature.com/articles/s41586-021-03646-5

Part 2

Comment by Dr. Krishna Kumari Challa on February 7, 2024 at 8:49am

Scientists Transformed Pure Water Into a Metal

Water found in nature conducts electricity – but that's because of the impurities therein, which dissolve into free ions that allow an electric current to flow. Pure water only becomes "metallic" – electronically conductive – at extremely high pressures, beyond our current abilities to produce in a lab.

But, as researchers demonstrated for the first time back in 2021, it's not only high pressures that can induce this metallicity in pure water.

By bringing pure water into contact with an electron-sharing alkali metal – in this case an alloy of sodium and potassium – free-moving charged particles can be added, turning water metallic.

The resulting conductivity only lasts a few seconds, but it's a significant step towards being able to understand this phase of water by studying it directly.

You can see the phase transition to metallic water with the naked eye! The silvery sodium-potassium droplet covers itself with a golden glow, which is very impressive.

Metallic water prepared for first time under terrestrial conditions

The idea is that if you squeeze the atoms together tightly enough, the orbitals of the outer electrons would start to overlap, allowing them to move around. For water, this pressure is around 48 megabars – just under 48 million times Earth's atmospheric pressure at sea level.

While pressures exceeding this have been generated in a laboratory setting, such experiments would be unsuitable for studying metallic water. So a team of researchers turned to alkali metals.

These substances release their outer electrons very easily, which means they could induce the electron-sharing properties of highly pressurized pure water without the high pressures.

Part 1

Comment by Dr. Krishna Kumari Challa on February 7, 2024 at 8:35am

However, the elasticity of the flagellum doesn’t fully explain how the cell is able to move, which is where odd elasticity comes in. This allows the cells to wiggle their flagella without expending much energy to their surroundings, which would otherwise suppress their motility. 

The higher a cell’s odd elasticity score (or odd elastic modulus), the more able a flagellum is to wave sans large energy loss, and so the cell is better able to move forward – in a way that defies physics.

Sperm and algae are not the only cells in possession of a flagellum – many microorganisms have one (they can make bacteria sound like they’re playing tiny drums)  – which means there are likely other rule-breakers out there to be discovered. Being able to understand and classify other cells or organisms capable of non-reciprocal movement could be very useful, the team behind the study told New Scientist.

Their approach could even help in the design of small elastic robots with the ability to break Newton’s third law, according to one of the study's authors, Kenta Ishimoto of Kyoto University in Japan.

Moreover, the odd elastic modulus can be calculated for any closed-loop system, meaning it could be applied to a wide range of biological data, including active elastic membranes and bulk dynamics, the authors explain in their conclusion.

Breaking the law has never been so beneficial.

The study is published in PRX Life.

https://journals.aps.org/prxlife/abstract/10.1103/PRXLife.1.023002

https://www.iflscience.com/sperm-caught-breaking-the-law-newtons-th...

Part 2

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Comment by Dr. Krishna Kumari Challa on February 7, 2024 at 8:33am

Sperm caught breaking Newton's third law of motion

Some biological cells swim freely in a way that apparently breaks one of Newton’s laws of motion – but only if they have strange elastic properties

HUMAN sperm cells and some microorganisms swim by deforming their bodies in a way that breaks Isaac Newton's third law of motion - and we are closer to understanding how they do it. The findings could inspire tiny swimming robots that also violate this law.

he laws of physics have been broken (or appear to have been broken) by all manner of things, from balancing rocks to Seinfeld’s apartment, and now, by human sperm. The latest law-breakers defy Newton's third law of motion, distorting their bodies as they swim in a way that elicits no response from their surroundings.

Newton's third law states that when one object exerts a force on a second object, the second object exerts an equal and opposite force back. In other words, “for every action, there is an equal and opposite reaction”. However, for biological swimmers such as sperm, this may not be the case.

In a new study, scientists analyzed Chlamydomonas algae and data on human sperm cells, identifying non-reciprocal mechanical interactions, which they call “odd elasticity”, that go against Newton’s third law.

Both Chlamydomonas and sperm cells use hair-like appendages called flagella to move around. These protrude from the cell, almost like a tail, helping to propel it forward by changing shape as they interact with the surrounding fluid. They do so in a non-reciprocal way, meaning they don’t provoke an equal and opposite response from their surroundings and therefore, flout Newton’s third law.

Part 1

Comment by Dr. Krishna Kumari Challa on February 7, 2024 at 6:26am

Looking into the possibility of volcanic lightning being the spark that ignited life on Earth

An international team of geologists, Earth scientists and mineralogists has found evidence suggesting that volcanic lightning may have fixed huge amounts of atmospheric nitrogen, allowing life on Earth to get its start.

In their study, published in the Proceedings of the National Academy of Sciences, the group collected and analyzed ancient volcanic deposits to learn more about how ancient eruptions may have produced nitrates that could have been used to create amino acids.

Prior research has shown that the development of life required fixing nitrogen, a key component of amino acids, during Earth's early years. In modern times, there is plenty of nitrogen in the atmosphere but plants cannot use it directly; it must first be fixed by bacteria that can convert it to nitrates or other nitrogen compounds.

That raises the question of how bacteria and then other life forms originated. In this new study, the researchers found evidence that nitrogen in the atmosphere could have been fixed by volcanic lightning interacting with ash.

Prior research has shown that lightning, whether due to thunderstorms or volcanic eruptions, can lead to the formation of nitrates under the right conditions. Lighting from thunderstorms has been ruled out as a candidate for production of the nitrates that led to the beginning of life due to the limited amounts that are produced.

To find out if the same held true for lightning produced during volcanic eruptions, the research team ventured to sites in Turkey, Italy and Peru, known to host ancient volcanic deposits. Samples from these sites contained large amounts of nitrates. Testing showed that they were atmospheric and had not come directly from the volcano—that left lightning as their likely source. But the thing that truly bolstered their theory was the huge amounts of nitrates they found, which were more than enough to serve as a source for creating amino acids.
The team notes that prior research efforts have led to theories that life began near volcanoes—and one team even found some evidence that suggested volcanic lightning interacting with volcanic gases could produce molecules used by living things, such as amino acids.

Adeline Aroskay et al, Geological evidence of extensive N-fixation by volcanic lightning during very large explosive eruptions, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2309131121

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