Comment

Comment by Dr. Krishna Kumari Challa on November 3, 2023 at 8:43am

Research shows one sleepless night can rapidly reverse depression for several days

Most people who have pulled an all-nighter are all too familiar with that "tired and wired" feeling. Although the body is physically exhausted, the brain feels slap-happy, loopy and almost giddy.

Now neurobiologists are the first to uncover what produces this punch-drunk effect. In a new study, researchers induced mild, acute sleep deprivation in mice and then examined their behaviors and brain activity. Not only did dopamine release increase during the acute sleep loss period, synaptic plasticity also was enhanced—literally rewiring the brain to maintain the bubbly mood for the next few days.

These new findings could help researchers better understand how mood states transition naturally. It also could lead to a more complete understanding of how fast-acting antidepressants (like ketamine) work and help researchers identify previously unknown targets for new antidepressant medications.

Chronic sleep loss is well studied, and it's uniformly detrimental effects are widely documented and it is not good.Scientists long have known that acute perturbations in sleep are associated with altered mental states and behaviors. Alterations of sleep and circadian rhythms in patients, for example, can trigger mania or occasionally reverse depressive episodes.

 But brief sleep loss—like the equivalent of a student pulling an all-nighter before an exam—is less understood. Now researchers found that sleep loss induces a potent antidepressant effect and rewires the brain. This is an important reminder of how our casual activities, such as a sleepless night, can fundamentally alter the brain in as little as a few hours.

Mingzheng Wu et al, Dopamine pathways mediating affective state transitions after sleep loss, Neuron (2023). DOI: 10.1016/j.neuron.2023.10.002. www.cell.com/neuron/fulltext/S0896-6273(23)00758-4

**

Comment by Dr. Krishna Kumari Challa on November 3, 2023 at 8:25am

Biomimetic melanin heals skin injuries from sunburn and chemical burns

Melanin in humans and animals provides pigmentation to the skin, eyes and hair. The substance protects your cells from sun damage with increased pigmentation in response to sunlight—a process commonly referred to as tanning. That same pigment in your skin also naturally scavenges free radicals in response to damaging environmental pollution from industrial sources and automobile exhaust fumes.

Imagine a skin cream that heals damage occurring throughout the day when your skin is exposed to sunlight or environmental toxins. That's the potential of a synthetic, biomimetic melanin developed by scientists.

In a new study,  scientists show that their synthetic melanin, mimicking the natural melanin in human skin, can be applied topically to injured skin, where it accelerates wound healing. These effects occur both in the skin itself and systemically in the body. When applied in a cream, the synthetic melanin can protect skin from sun exposure and heals skin injured by sun damage or chemical burns, the scientists said.

The technology works by scavenging free radicals, which are produced by injured skin such as a sunburn. Left unchecked, free radical activity damages cells and ultimately may result in skin aging and skin cancer.

Topical Application of Synthetic Melanin Promotes Tissue Repair, npj Regenerative Medicine (2023).

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 11:44am

Scientists Just Discovered a New Human Sense of Touch

A new study reveals a previously undiscovered way that we can feel light touches: directly through our hair follicles. Before now, it was thought that only nerve endings in the skin and around the hair follicles could transmit the sensation.

Researchers used an RNA sequencing process to find that cells in part of the hair follicle called the outer root sheath (ORS) had a higher percentage of touch-sensitive receptors than equivalent cells in the skin.

From there, the researchers produced lab cultures of human hair follicle cells together with sensory nerves.

When the hair follicle cells were mechanically stimulated, the sensory nerves next to them were also activated – showing that touch had been registered.

The experiments also revealed that the neurotransmitters serotonin and histamine were being released by the ORS cells through tiny sacs called vesicles, as a way of signaling to the surrounding cells.

Touch-sensing nerve cells are known as mechanoreceptors. They're the reason we can feel everything from a light breeze to a firm press. In this case, the hair follicle cells were interacting specifically with low-threshold mechanoreceptors (LTMRs), capable of feeling gentle touches.

https://www.science.org/doi/10.1126/sciadv.adh3273

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 11:36am

How Could a Piece of the Moon Become a Near-Earth Asteroid? Researchers Have an Answer

A team of astronomers has found a new clue that a recently discovered near-Earth asteroid, Kamo`oalewa, might be a chunk of the moon. They hypothesized that the asteroid was ejected from the lunar surface during a meteorite strike–and they found that a rare pathway could have allowed Kamo`oalewa to get into orbit around the sun while remaining close to the orbits of the Earth and the Moon.

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 10:14am

In a fascinating paper authored by Toth and posted to the arXiv preprint server, he explores the possibility that multiple gravitational lenses might provide extra amplification of light to provide a communication bridge between distant civilizations.

In a conventional gravitational lens, a large mass—such as a cluster of galaxies—sits between a more distant object and the Earth. As the light travels from the distant object, it is bent around the galaxy cluster, providing a lensing effect to astronomers on Earth, allowing them to a) study the distribution of matter in the lensing cluster but also to observe the more distant object a little more easily. Toth proposes that, just like a conventional telescope that uses multiple lenses, a multiple gravitational lens could provide even more amplification than a single system.

Toth explores combinations of multiple gravitational lenses using a variety of methods but focuses (sorry) attention on a two-lens system (so-called gravitational lens bridge), which is aligned along the central axis of the system, but found no advantages and no additional signal amplification over the results from a single lens system. In addition, photon mapping techniques were applied with the same outcome; a double-lens system offers no advantage over a single-lens system.

Applying the wave theory of light to the same two-lens system revealed the same results, but using computer graphics to perform ray tracing (which cannot be used to estimate amplification) can help to highlight visual features other techniques would be unable to produce. Using this approach, it suggested a two-lens system would produce two concentric Einstein rings; however, they would be very difficult to detect in real-world scenarios. In summary, then, a fascinating concept, especially the possibility of using a lens bridge for communication with distant civilizations, but the results are less than promising. Yes, there may well be double gravitational lenses, but as this paper shows, it is unlikely we will be able to detect them for now and sadly I suspect the idea of using them as a long-distance cosmic telephone will for now remain science fiction.

 Viktor T. Toth, Non-coplanar gravitational lenses and the "communication bridge", arXiv (2023). DOI: 10.48550/arxiv.2310.15957

Part 2

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 10:10am

Double gravitational lenses?!

How cool is it that the very universe we are trying to explore is actually providing us with telescopes to probe the darkest corners of space and time?

The alignment of large clusters of galaxies is the usual culprit whose gravity bends distant light to give us nature's own telescopes, but now our own Quora  physicist Viktor T Toth poses the question, "Can there be multiple gravitational lenses lined up and can they provide a 'communication bridge' to allow civilizations to communicate?"

 Albert Einstein in his general theory of relativity,  describes how the presence of matter can distort space around them. The famous analogy of placing a bowling ball at the center of a large rubber sheet causes a dip centered around the mass of the bowling ball. Any object rolling past the ball would find itself traveling through "curved space" and, therefore, find its path to be altered. This very concept is used successfully by space mission planners to adjust the trajectory of spacecraft exploring the solar system.

The same concept applies to light as it passes by massive objects like galaxy clusters and is the principle behind the gravitational lense. The first evidence of light being deflected by a massive object was performed in 1919 by Arthur Eddington and Frank Watson Dyson during a total solar eclipse. Gravitational lenses entered the scene 60 years later when they were first observed in 1979 by Dennis Walsh, Bob Carswell, and Ray Weymann using the 2.1m telescope at the Kitt Peak National Observatory.

Part 1

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 9:48am

Human emissions have increased mercury in the atmosphere sevenfold: Study

Humans have increased the concentration of potentially toxic mercury in the atmosphere sevenfold since the beginning of the modern era around 1500 C.E., according to new research .

Researchers developed a new method to accurately estimate how much mercury is emitted annually from volcanos, the largest single natural emitter of mercury. The team used that estimate—along with a computer model—to reconstruct pre-anthropogenic atmospheric mercury levels. The researchers estimated that before humans started pumping mercury into the atmosphere, it contained on average about 580 megagrams of mercury. However, in 2015, independent research that looked at all available atmospheric measurements estimated the atmospheric mercury reservoir was about 4,000 Mg—nearly 7 times larger than the natural condition estimated in this study. Human emissions of mercury from coal-fired power plants, waste-incineration, industry and mining make up the difference. 

Methylmercury is a potent neurotoxicant that bioaccumulates in fish and other organisms—including us.

 Benjamin M. Geyman et al, Impacts of Volcanic Emissions on the Global Biogeochemical Mercury Cycle: Insights From Satellite Observations and Chemical Transport Modeling, Geophysical Research Letters (2023). DOI: 10.1029/2023GL104667

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 9:21am

New insights into the India–Asia collision in the Western Himalayas dating back to circa 55 million years

New Sangdanlin Section Data Suggests a Large Greater India

Comment by Dr. Krishna Kumari Challa on November 2, 2023 at 8:50am

Star fishes are just heads!

For centuries, naturalists have puzzled over what might constitute the head of a sea star, commonly called a "starfish." When looking at a worm, or a fish, it's clear which end is the head and which is the tail. But with their five identical arms—any of which can take the lead in propelling sea stars across the seabed—it's been anybody's guess how to determine the front end of the organism from the back. This unusual body plan has led many to conclude that sea stars perhaps don't have a head at all.

Researchers now have published a study finding that the truth is closer to the absolute reverse. In short, while the team detected gene signatures associated with head development just about everywhere in juvenile sea stars, expression of genes that code for an animal's torso and tail sections were largely missing.

Researchers used a variety of high-tech molecular and genomic techniques to understand where different genes were expressed during the development and growth of sea stars. A team  used micro-CT scanning to understand the shape and structure of the animal in unprecedented detail.

In another surprising finding, molecular signatures typically associated with the front-most portion of the head were localized to the middle of each of the sea star's arms, with these signatures becoming progressively more posterior moving out towards the arms' edges.

The research, published Nov. 1 in Nature, suggests that, far from being headless, over evolutionary time sea stars lost their bodies to become only heads.

It's as if the sea star is completely missing a trunk, and is best described as just a head crawling along the seafloor.

Almost all animals, including humans, are bilaterally symmetrical, meaning they can be split into two mirrored halves along a single axis extending from their head to their tail.

But the body plan of sea stars has long confounded scientists' understanding of animal evolution. Instead of displaying bilateral symmetry, adult sea stars—and related echinoderms, such as sea urchins and sea cucumbers—have a five-fold axis of symmetry without a clear head or tail.

 Laurent Formery, Molecular evidence of anteroposterior patterning in adult echinoderms, Nature (2023). DOI: 10.1038/s41586-023-06669-2. www.nature.com/articles/s41586-023-06669-2

Comment by Dr. Krishna Kumari Challa on November 1, 2023 at 12:14pm

Study directly links high insulin levels to pancreatic cancer

A new study from researchers reveals a direct link between high insulin levels, common among patients with obesity and type 2 diabetes, and pancreatic cancer.

The study, published in Cell Metabolism, provides the first detailed explanation of why people with obesity and type 2 diabetes are at an increased risk of pancreatic cancer. The research demonstrates that excessive insulin levels overstimulate pancreatic acinar cells, which produce digestive juices. This overstimulation leads to inflammation that converts these cells into precancerous cells.

While obesity and type 2 diabetes had previously been established as risk factors for pancreatic cancer, the exact mechanisms by which this occurred remained unclear. This new study sheds light on the role of insulin and its receptors in this process.

Hyperinsulinemia acts via acinar insulin receptors to initiate pancreatic cancer by increasing digestive enzyme production and inflammation, Cell Metabolism (2023). DOI: 10.1016/j.cmet.2023.10.003. www.cell.com/cell-metabolism/f … 1550-4131(23)00372-8

• ‹ Previous
• 1
• …
• 245
• 246
• 247
• 248
• 249
• …
• 1006
• Next ›
• Page