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Comment by Dr. Krishna Kumari Challa on December 27, 2023 at 10:12am

Could One Physics Theory Unlock the Mysteries of the Brain?

The ability of the phenomenon of criticality to explain the sudden emergence of new properties in complex systems has fascinated scientists in recent decades. When systems are balanced at their “critical point,” small changes in individual units can trigger outsized events, just as falling pebbles can start an avalanche. That abrupt shift in behavior describes the phase changes of water from ice to liquid to gas, but it’s also relevant to many other situations, from flocks of starlings on the wing to stock market crashes. In the 1990s, the physicist Per Bak and other scientists suggested that the brain might be operating near its own critical point. Ever since then, neuroscientists have been searching for evidence of fractal patterns and power laws at work in the brain’s networks of neurons. What was once a fringe theory has begun to attract more mainstream attention, with researchers now hunting for mechanisms capable of tuning brains toward criticality.

Comment by Dr. Krishna Kumari Challa on December 26, 2023 at 11:42am

Hormone secreted by fetus causes morning sickness: study

A hormone produced by the human fetus is to blame for morning sickness in pregnant women, a study has found, paving the way to possible prevention and treatment.

Nausea and vomiting affect approximately 70 percent of pregnant women, according to the study published in Nature recently  by researchers.

 In its worst form, hyperemesis gravidarum, the nausea and vomiting is so severe that women are unable to eat or drink normally. The culprit is a hormone produced by the fetus—a protein known as GDF15. But how sick the mother feels depends on a combination of how much of the hormone is produced by the fetus and how much exposure the mother had to this hormone before becoming pregnant.

The discovery points to a potential way to prevent pregnancy sickness by exposing mothers to GDF15 ahead of pregnancy to build up their resilience. It makes us more confident that preventing GDF15 from accessing its highly specific receptor in the mother's brain will ultimately form the basis for an effective and safe way of treating this disorder.

Stephen O'Rahilly, Gdf15 linked to maternal risk of nausea and vomiting during pregnancy, Nature (2023). DOI: 10.1038/s41586-023-06921-9. www.nature.com/articles/s41586-023-06921-9

Comment by Dr. Krishna Kumari Challa on December 26, 2023 at 11:23am

Mineral wool is often used as cultivation substrate in hydroponics. Not only is this non-biodegradable, it is also produced with a very energy-intensive process. The electronic cultivation substrate eSoil is made of cellulose, the most abundant biopolymer, mixed with a conductive polymer called PEDOT. This combination as such is not new, but this is the first time it has been used for plant cultivation and for creating an interface for plants in this manner.

Previous research has used high voltage to stimulate the roots. The advantage of the new work is that it has very low energy consumption and no high voltage danger. The new study will open the pathway for new research areas to develop further hydroponic cultivation, the researchers say.

They also say, "We can't say that hydroponics will solve the problem of food security. But it can definitely help particularly in areas with little arable land and with harsh environmental conditions".

 A low-power bioelectronic growth scaffold that enhances crop seedling growth, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2304135120. doi.org/10.1073/pnas.2304135120

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Comment by Dr. Krishna Kumari Challa on December 26, 2023 at 11:21am

Researchers develop 'electronic soil' that enhances crop growth

Barley seedlings grow on average 50% more when their root system is stimulated electrically through a new cultivation substrate. In a study published in the journal PNAS, researchers  have developed an electrically conductive "soil" for soilless cultivation, known as hydroponics.

The world population is increasing, and we also have climate change. So it's clear that we won't be able to cover the food demands of the planet with only the already existing agricultural methods. But with hydroponics we can grow food also in urban environments in very controlled settings.

Researchers  now developed an electrically conductive cultivation substrate, tailored to hydroponic cultivation, that they call eSoil. The researchers have shown that barley seedlings grown in the conductive "soil" grew up to 50% more in 15 days when their roots were stimulated electrically.

Hydroponic cultivation means that plants grow without soil, needing only water, nutrients and something their roots can attach to—a substrate. It is a closed system that enables water recirculation so that each seedling gets exactly the nutrients it needs. Therefore, very little water is required and all nutrients remain in the system, which is not possible in traditional cultivation.

Hydroponics also enables vertical cultivation in large towers to maximize space efficiency. Crops already being cultivated in this manner include lettuce, herbs and some vegetables. Grains are not typically grown in hydroponics apart for their use as fodder. In this study the researchers show that barley seedlings can be cultivated using hydroponics and that they have a better growth rate thanks to electrical stimulation. They have have found  that seedlings process nitrogen more effectively, but it's not clear yet how the electrical simulation impacts this process.

Part 1

Comment by Dr. Krishna Kumari Challa on December 25, 2023 at 11:17am

Based on the helioseismology studies we've done, there is almost certainly NOT a black hole in our sun. Or if there is, it would need to be exceedingly tiny. So there's no need to pack your bug-out bag for a solar doomsday. But perhaps there are some Hawking stars out there if we only care to look.

More information: Matthew E. Caplan et al, Is there a black hole in the center of the Sun?, arXiv (2023). DOI: 10.48550/arxiv.2312.07647

Part 2

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Could there be a black hole inside the sun?

Comment by Dr. Krishna Kumari Challa on December 25, 2023 at 11:16am

It's a classic tale of apocalyptic fiction. The sun, our precious source of heat and light, collapses into a black hole. Or perhaps a stray black hole comes along and swallows it up. The End is Nigh! If a stellar-mass black hole swallowed our sun, then we'd only have about eight minutes before, as the kids say, it gets real. But suppose the sun swallowed a small primordial black hole? Then things get interesting, and that's definitely worth a paper on the arXiv preprint server.

Primordial black holes are hypothetical black holes that formed during the earliest moments of the universe. Unlike stellar-mass black holes or supermassive black holes, primordial black holes would typically be tiny, with a mass roughly that of an asteroid and a size smaller than a baseball. They show up in certain theoretical models and have been used to try to explain everything from dark matter to a distant Planet X. Many of these models argue that primordial black holes are common, so it's inevitable that a star would eventually capture one. Such stars with a black hole center are known as Hawking stars.
As this new work points out, a captured primordial black hole would initially have almost no effect on a sun-like star. Compared to the mass of the sun, an asteroid's worth of mass might as well be a speck of dust. Even if it were a black hole it couldn't consume much of the sun quickly. But it would affect things over time. A black hole in a star would consume matter in the stellar core and grow over time. If it could grow quickly on a cosmological scale, then it could consume a star completely. If not, it could still affect the evolution and end life of the star.
The study shows that it largely comes down to the initial size of the primordial black hole. For ones at the largest mass range not excluded by observations, around a billionth of a solar mass, it could essentially consume a star in less than half a billion years. If this has happened, then there should be solar mass black holes out there, which are too small to have formed from supernovae like traditional stellar-mass black holes.
If the primordial black hole is much smaller, say less than a trillionth of a solar mass, then things get more complicated. The tiny black hole would consume some matter within the star, but not at a fast pace. It would, however, stir things up in the core, heating it up more than fusion alone. As a result, a star could swell into a "red straggler" which would be cooler and redder than usual red giant stars. All that turbulence in the core could also affect the surface activity of the star. The effects would be subtle, but the authors suggest that the presence of a primordial black hole could be seen through stellar seismology.
Part 1

Comment by Dr. Krishna Kumari Challa on December 23, 2023 at 12:19pm

Cancer-fighting cells made inside body

Viruses that infect immune cells could turn them into cancer-targeting agents — without having to remove the cells from the person receiving treatment, genetically edit them and then reintroduce them to their body. Genetically engineered chimeric antigen receptor (CAR) T cells have yielded dramatic recoveries from some blood cancers — but are notoriously expensive and technically difficult, placing them out of reach for many people. In tests with monkeys, an injection of a virus that inserts genes into the animal’s immune cells mimicked the action of approved CAR-T therapies.

https://www.nature.com/articles/d41586-023-03969-5?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on December 23, 2023 at 10:11am

Night mode on screens—useful or not?

We often hear that the short-wavelength component of light from smartphone and tablet screens affects biological rhythms and sleep. The recommendation is therefore to put your mobile phone away early in the evening or at least use the night shift mode, which reduces the short-wavelength light proportions and looks slightly yellowish.  However, the yellowish color adjustment is a by-product that could be avoided.

Technologically, it is possible to reduce the short-wavelength proportions even without color adjustment of the display; however, this has not yet been implemented in commercial mobile phone displays.

 Effects of calibrated blue–yellow changes in light on the human circadian clock, Nature Human Behaviour (2023). DOI: 10.1038/s41562-023-01791-7

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Comment by Dr. Krishna Kumari Challa on December 23, 2023 at 10:09am

To get to the bottom of this, the researchers exposed 16 healthy volunteers to a bluish or yellowish light stimulus for one hour in the late evening, as well as a white light stimulus as a control condition. The light stimuli were designed in such a way that they differentially activated the color-sensitive cones in the retina in a very controlled manner.

However, the stimulation of the light-sensitive ganglion cells was the same in all three conditions. Differences in the effect of the light were therefore directly attributable to the respective stimulation of the cones and ultimately the color of the light.

This method of light stimulation allows us to separate the light properties that may play a role in how light effects humans in a clean experimental way.

In order to understand the effects of the different light stimuli on the body, in the sleep laboratory the researchers determined whether the internal clock of the participants had changed depending on the color of the light. Additionally, they assessed how long it took the volunteers to fall asleep and how deep their sleep was at the beginning of the night. The researchers also enquired about their tiredness and tested their ability to react, which decreases with increasing sleepiness.

The conclusion: The researchers  found no evidence that the variation of light color along a blue-yellow dimension plays a relevant role for the human internal clock or sleep. This contradicts the results of the mouse study mentioned above. Rather, these new results support the findings of many other studies that the light-sensitive ganglion cells are most important for the human internal clock.

These findings show that it is probably most important to take into account the effect of light on the light-sensitive ganglion cells when planning and designing lighting. The cones, and therefore the color, play a very subordinate role.

It remains to be seen whether the color of the light also has no effect on sleep if the parameters change, and—for example—the duration of the light exposure is extended or takes place at a different time. Follow-up studies should answer questions like these.

Part 2

Comment by Dr. Krishna Kumari Challa on December 23, 2023 at 10:06am

Light color is less important for the internal clock than originally thought, new study finds

Vision is a complex process. The visual perception of the environment is created by a combination of different wavelengths of light, which are decoded as colors and brightness in the brain. Photoreceptors in the retina first convert the light into electrical impulses: with sufficient light, the cones enable sharp, detailed, and colored vision. Rods only contribute to vision in low light conditions, allowing for different shades of gray to be distinguished, but leaving vision much less precise.

The electrical nerve impulses are finally transmitted to ganglion cells in the retina and then via the optic nerve to the visual cortex in the brain. This region of the brain processes the neural activity into a coloured image.

Ambient light, however, does not only allow us to see; it also influences our sleep-wake rhythm. Specialized ganglion cells are significantly involved in this process, which—like the cones and rods—are sensitive to light and react particularly strongly to short-wavelength light at a wavelength of around 490 nanometers. If light consists solely of short wavelengths of 440 to 490 nanometers, we perceive it as blue. If short-wavelength light activates the ganglion cells, they signal to the internal clock that it is daytime. The decisive factor here is how intense the light is per wavelength; the perceived color is not relevant. However, the light-sensitive ganglion cells also receive information from the cones. This raises the question of whether the cones, and thereby the light color, also influence the internal clock. After all, the most striking changes in brightness and light color occur at sunrise and sunset, marking the beginning and end of a day.

A study in mice in 2019 suggested that yellowish light has a stronger influence on the internal clock than bluish light. However, there is reason to think that the color of light, which is encoded by the cones, could also be relevant for the internal clock.

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