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Comment by Dr. Krishna Kumari Challa on February 13, 2021 at 9:21am

Electron refrigerator: Ultrafast cooling mechanism discovered in novel plasma

Researchers from the Cluster of Excellence "CUI: Advanced Imaging of Matter" have achieved a breakthrough—creating a completely new type of plasma by combining state-of-the-art technologies using ultrashort laser pulses and ultracold atomic gases. They report on a novel electron cooling mechanism occurring in such plasmas in the journal Nature Communications.

Matter exists in four states—solid, gas, liquid, and plasma—with plasma being the most abundant state in the visible universe. It consists of free charged particles such as ions and electrons. Plasmas can exist over a tremendous range of temperatures and densities, from the sun's core to lightning or flames. The challenges to understand plasma dynamics are first to identify universal mechanisms and then compare them to a controlled laboratory experiment. 

the researchers cool and trap atoms with laser light. They use the intense light field of an ultrashort laser pulse to break up atoms into electrons and ions within 200 femtoseconds. A femtosecond is one millionth of one billionth of a second. Because of the extremely low initial temperature of the atoms, the ions have temperatures lower than 40 millikelvin, which is only a fraction above the lowest possible temperature in the universe (0 Kelvin or minus 273 degree on the Celsius scale). In contrast, the electrons are initially very hot with temperatures of 5250 Kelvin, close to the ones found at the surface of the sun.

Hot electrons directly created by the ultrashort laser pulse begin to escape and leave behind a positively charged region that traps some of the electrons in an ultracold plasma. Such a plasma state has never been observed before.

The researchers  also observed that the trapped electrons in the plasma are cooled on ultrafast timescales and measured the final electronic temperature. In addition, they observed that the plasma is stable over a few hundred nanoseconds, which is a very long time for such systems.

Such ultracold plasmas provide benchmarks for theoretical models and can shed light on extreme conditions present in inertial confinement fusion or astronomical objects such as white dwarfs. Furthermore, the resulting ultracold electrons are interesting by themselves as a bright source for imaging biological samples.

Tobias Kroker et al. Ultrafast electron cooling in an expanding ultracold plasma, Nature Communications (2021). DOI: 10.1038/s41467-020-20815-8

https://phys.org/news/2021-02-electron-refrigerator-ultrafast-cooli...

Comment by Dr. Krishna Kumari Challa on February 13, 2021 at 9:15am

Tuning the circadian clock, boosting rhythms may be key to future treatments and medicines

Subconsciously, our bodies keep time for us through an ancient means—the circadian clock. A new  article reviews how the clock controls various aspects of homeostasis, and how organs coordinate their function over the course of a day.

What is fascinating is that nearly every cell that makes up our organs has its own clock, and thus timing is a crucial aspect of biology. Understanding how daily timing is integrated with function across organs has implications for human health, as disruption of the clock and circadian rhythms can be both a cause and effect of diseases from diabetes to cancer.

The circadian clock generates a ~24 hour rhythm that controls behavior, hormones, the immune system and metabolism. Using human cells and mice, researchers  aim to uncover the physiological circuits, for example between the brain and liver, whereby biological clocks achieve coherence. Their work, titled, "Communicating clocks shape circadian homeostasis," was published recently in Science.

Circadian clocks align internal processes with external time, which enables diverse lifeforms to anticipate daily environmental changes such as the light-dark cycle. In complex organisms, clock function starts with the genetically encoded molecular clock or oscillator within each cell and builds upward anatomically into an organism-wide system. Circadian misalignment, often imposed in modern society, can disrupt this system and induce adverse effects on health if prolonged.

Strategies to tune our clocks and boost rhythms have been promising in pre-clinical studies, which illustrates the importance of unraveling this aspect of our biology and unlocking the potential it holds for treatments and medicines of the future.

Without electrical light, high-speed travel, constant food availability and around the clock work-life schedules, our ancestors' clocks were in constant harmony with the environment. However, due to these pressures of modern society, aligning our internal time with geophysical time has become a challenge in today's world. Chronic misalignment—when eating and sleeping patterns conflict with the natural light-dark cycle—is associated with an increased risk of metabolic syndrome, cardiovascular disease, neurological conditions, and cancer. A large portion of the global workforce has atypical hours and may be particularly vulnerable.

It has become urgent that we uncover the molecular underpinnings of the relationship between the circadian clock and disease. Deciphering the means by which clocks communicate across metabolic organs has the potential to transform our understanding of metabolism, and it may hold therapeutic promise for innovative, noninvasive strategies to promote health.

 Kevin B. Koronowski et al, Communicating clocks shape circadian homeostasis, Science (2021). DOI: 10.1126/science.abd0951

https://medicalxpress.com/news/2021-02-tuning-circadian-clock-boost...

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Comment by Dr. Krishna Kumari Challa on February 13, 2021 at 8:59am

Women better at reading minds than men, new study finds

Psychologists  have developed the first ever 'mind-reading questionnaire' to assess how well people understand what others are really thinking.

A new approach to 'mind-reading' has been developed by researchers at the University of Bath, Cardiff, and London to improve how well we understand what others are thinking. And it transpires that women are much better than men at putting themselves in someone else's shoes.

Mind-reading, sometimes referred to in psychology as 'mentalising', is an important ability enabling us to pick-up on subtle behavioural cues that might indicate that someone we are speaking to is thinking something that they are not saying (e.g. being sarcastic or even lying).

The researchers say that we all have different mind-reading abilities, with some of us inherently better than others. The fact that not all of us are good at mind-reading can cause challenges—in particular for people with autism where it can lead to social struggles in building or maintaining relationships.

Rachel A. Clutterbuck et al, Development and validation of the Four-Item Mentalising Index., Psychological Assessment (2021). DOI: 10.1037/pas0001004

https://medicalxpress.com/news/2021-02-women-minds-men.html?utm_sou...

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Comment by Dr. Krishna Kumari Challa on February 13, 2021 at 8:56am

Birds can 'read' the Earth's magnetic signature well enough to get back on course

Birdwatchers get very excited when a 'rare' migratory bird makes landfall having been blown off-course and flown beyond its normal range. But these are rare for a reason; most birds that have made the journey before are able to correct for large displacements and find their final destination.

Now, new research by an international team shows for the first time, how birds displaced in this way are able to navigate back to their migratory route and gives us an insight into how they accomplish this feat. They describe how reed warblers can navigate from a 'magnetic position' beyond what they have experienced in their normal migration route, back towards that correct route.

Different parts of the Earth have a distinct 'geomagnetic signature' according to their location. This is a combination of the strength of the geomagnetic field, the magnetic inclination or the dip angle between magnetic field lines and the horizon and the magnetic declination, or the angle between directions to the geographic and magnetic North poles.

Adult birds already familiar with their migration route, and its general magnetic signatures, were held in captivity for a short period before being released back into the wild, and exposed to a simulation of the earth's magnetic signature at a location thousands of miles beyond the birds' natural migratory corridor. Despite remaining physically located at their capture site and experiencing all other sensory clues about their location, including starlight and the sights, smell and sounds of their actual location, the birds still showed the urge to begin their journey as though they were in the location suggested by the magnetic signal they were experiencing.

They oriented themselves to fly in a direction which would lead them 'back' to their migratory path from the location suggested to them by the magnetic signals they were experiencing.

This shows that the earth's magnetic field is the key factor in guiding reed warblers when they are blown off course. The overriding impulse was to respond to the magnetic information they were receiving. current work shows is that birds are able to sense that they are beyond the bounds of the magnetic fields that are familiar to them from their year-round movements, and are able to extrapolate their position sufficiently from the signals. This fascinating ability enables bird to navigate towards their normal migration route.

What these birds are achieving is "true navigation". In other words, they are able to return to a known goal after displacement to a completely unknown location without relying on familiar surroundings, cues that emanate from the destination, or information collected during the outward journey.

But questions remain about whether the birds have an accurate 'map' or are just using a 'rule of thumb' measurement to judge the general direction of travel needed to get back on course.

"Navigation by extrapolation of geomagnetic cues in a migratory songbird" Current Biology, DOI: 10.1016/j.cub.2021.01.051

https://phys.org/news/2021-02-birds-earth-magnetic-signature.html?u...

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Comment by Dr. Krishna Kumari Challa on February 13, 2021 at 7:02am

Scientists Think They've Figured Out What's Triggering Brain Fog in COVID-19 Patients
Not long after the first wave of COVID-19 infections hit, doctors all around the world began to notice something strange – a host of lingering effects persisting in patients, long after they appeared to have otherwise recovered from the virus.

These unusual neurological symptoms – encompassing fatigue, memory loss, confusion, and other abnormalities – are sometimes known as 'brain fog' or 'COVID brain', and new research may have identified an underlying cause of the condition.

As part of the new study, researchers screened the cerebrospinal fluid of 18 cancer patients who were experiencing neurological dysfunction (aka encephalopathy) after having been infected with the SARS-CoV-2 virus.

Initially, it was suspected that an ongoing viral infection might be the cause of their brain fog symptoms, but microbiological analysis of fluid taken in spinal taps did not reveal any sign of the virus, suggesting the patients had recovered from COVID-19.

They found that these patients had persistent inflammation and high levels of cytokines in their cerebrospinal fluid, which explained the symptoms they were having.

Cytokines are a broad category of proteins that are involved with signalling in the immune system.

In some cases of coronavirus, an over-production of these molecules results in what's known as a cytokine storm, which can cause excessive inflammation and is potentially deadly.

A similar phenomenon showing high levels of inflammatory cytokines is sometimes seen as a side effect of chimeric antibody receptor (CAR) T cell therapy, an immunotherapy treatment, which can also produce confusion, delirium, and other neurological effects that bear a resemblance to COVID brain fog.

The thinking is that the flood of these inflammatory chemicals in the immune system seeps into the brain, producing symptoms of encephalopathy as seen in patients. 

The findings here suggest anti-inflammatory drugs might be helpful in mitigating brain fog in patients, and could highlight new directions in terms of diagnosing this strange, lingering malaise.

Researchers used to think that the nervous system was an immune-privileged organ, meaning that it didn't have any kind of relationship at all with the immune system.

But the more scientists looked, the more the connections connections between the two were found.

https://www.cell.com/cancer-cell/fulltext/S1535-6108(21)00051-9

https://www.sciencealert.com/scientists-may-have-identified-what-ca...

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 10:28am

Human Cells Can Synthesize DNA in Their Cytoplasm

While studying a degenerative eye disease, researchers find the first evidence that cells produce endogenous DNA in the cytoplasm. Drugs that block this activity are linked with reduced risk of atrophic age-related macular degeneration.

Over the past decade, there have been scattered reports of mammalian cells’ own DNA being found in the cytoplasm, mainly in the context of disease and aging. While it is not unusual to find DNA from an invading organism there, the presence of an organism’s own genetic code—in the form of complementary DNA (cDNA) synthesized from an RNA template—has puzzled scientists. In each case, the cDNA has come from endogenous retrotransposons, known for their copy-and-paste mechanism that results in the insertion of new copies of themselves into the genome. This process typically takes place in the nucleus, so the cytoplasmic cDNA lacked an explanation.

After detecting cDNA of Alu, the most abundant retrotransposon in the human genome, in the cytoplasm of cells modeling a degenerative eye disease, University of Virginia ophthalmologist Jayakrishna Ambati and his colleagues decided to investigate its mysterious origin. Their results, reported February 1 in PNAS, reveal that human cells can actually synthesize cDNA of Alu in the cytoplasm.

S. Fukuda et al., “Cytoplasmic synthesis of endogenous Alu complementary DNA via reverse transcription and implications in age-related macular degeneration,” PNAS, doi:10.1073/pnas.2022751118, 2021.

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 10:13am

An Optical Coating Like No Other

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 10:09am

Synchronization of brain hemispheres changes what we hear

How come we don’t hear everything twice: After all, our ears sit on opposite sides of our head and most sounds do not reach both our ears at exactly the same time. While this helps us determine which direction sounds are coming from, it also means that our brain has to combine the information from both ears. Otherwise, we would hear an echo.

In addition, input from the right ear reaches the left brain hemisphere first, while input from the left ear reaches the right brain hemisphere first. The two hemispheres perform different tasks during speech processing: The left side is responsible for distinguishing phonemes and syllables, whereas the right side recognizes the speech prosody and rhythm. Although each hemisphere receives the information at a different time and processes different features of speech, the brain integrates what it hears into a unified speech sound.

The exact mechanism behind this integration process was not known until now. 

Now researchers have managed to demonstrate that the process of integrating what we hear is directly linked to synchronization by gamma waves.

During the experiments, the researchers disrupted the natural activity pattern of gamma waves by stimulating both hemispheres of the brain with electrodes attached to the head. This manipulation affected participants’ ability to correctly identify the syllable they heard. The fMRI analysis showed that there were also changes in the activity of the neural connections between the right and the left brain hemispheres: The strength of the connection changed depending on whether the rhythm of the gamma waves was influenced by electric stimulation in the two brain hemispheres synchronously or asynchronously. This disruption also impaired the integration process. Thus, synchronization of the gamma waves seems to serve to balance the different inputs from the two hemispheres of the brain, providing a unified auditory impression.

These findings could thus also find clinical application in the near future. “Previous studies show that disturbances in the connection between the two hemispheres of the brain are associated with auditory phantom perceptions such as tinnitus and auditory verbal hallucinations. Thus, electric brain stimulation may present a promising avenue for the development of therapeutic interventions.

Preisig BC, Riecke L, Sjerps M, Kösem A, Kop BR, Bramson B, Hagoort P, Hervais-Adelman A. Selective modulation of interhemispheric connectivity by transcranial alternating current stimulation influences binaural integration. PNAS, 2021 DOI: 10.1073/pnas.2015488118

https://www.sciencedaily.com/releases/2021/02/210208173103.htm#:~:t....

https://researchnews.cc/news/5061/Synchronization-of-brain-hemisphe...

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 9:08am

A reeking, parasitic plant lost its body and much of its genetic blueprint

The genome of Sapria himalayana is rife with gene loss and theft

New research on the genetic instruction book of a rare plant Sapria genus reveals the lengths to which it has gone to become a specialized parasite. The findings, published January 22 in Current Biology, suggest that at least one species of Sapria has lost nearly half of the genes commonly found in other flowering plants and stolen many others directly from its hosts. 

The plant’s rewired genetics echo its bizarre biology. Sapria and its relatives in the family Rafflesiaceae have discarded their stems, roots and any photosynthetic tissue.

About 44 percent of the genes found in most flowering plants were missing in S. himalayana. Yet, at the same time, the genome is about 55,000 genes long, more than that of some other nonparasitic plants. The count is inflated by many repeating segments of DNA, the team found.

Loss of the chlorophyll pigments responsible for photosynthesis is common in parasitic plants that rely on their hosts for sustenance. But S. himalayana appears to have even scrapped all genetic remnants of its chloroplasts, the cellular structures where photosynthesis occurs. 

Chloroplasts have their own genome, distinct from the nuclear genome that runs a plant’s cells and the mitochondria that produce energy for the cells. S. himalayana seems to have lost this genome altogether, suggesting that the plant has purged the last remnants of its ancestral life that allowed it to make its own food.

even genes in S. himalayana’s nuclear genome that would regulate components of the chloroplast genome have vanished. 

Among the remaining parts of the nuclear genome, it was  also found that more than 1 percent of S. himalayana’s genome comes from genes stolen from other plants, likely its current and ancestral hosts.

The new discovery illustrates the level of commitment S. himalayana and its relatives have given to evolving a parasitic lifestyle

https://www.cell.com/current-biology/fulltext/S0960-9822(20)31897-2?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982220318972%3Fshowall%3Dtrue

https://www.sciencenews.org/article/reeking-parasitic-sapria-plant-...

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 9:02am

Reconstructing Molecules in Motion

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