Posts Tagged ‘sun’

By Ruth Williams

The sun’s ultraviolet (UV) radiation is a major cause of skin cancer, but it offers some health benefits too, such as boosting production of essential vitamin D and improving mood. A recent report in Cell adds enhanced learning and memory to UV’s unexpected benefits.

Researchers have discovered that, in mice, exposure to UV light activates a molecular pathway that increases production of the brain chemical glutamate, heightening the animals’ ability to learn and remember.

“The subject is of strong interest, because it provides additional support for the recently proposed theory of ultraviolet light’s regulation of the brain and central neuroendocrine system,” dermatologist Andrzej Slominski of the University of Alabama who was not involved in the research writes in an email to The Scientist.

“It’s an interesting and timely paper investigating the skin-brain connection,” notes skin scientist Martin Steinhoff of University College Dublin’s Center for Biomedical Engineering who also did not participate in the research. “The authors make an interesting observation linking moderate UV exposure to . . . [production of] the molecule urocanic acid. They hypothesize that this molecule enters the brain, activates glutaminergic neurons through glutamate release, and that memory and learning are increased.”

While the work is “fascinating, very meticulous, and extremely detailed,” says dermatologist David Fisher of Massachusetts General Hospital and Harvard Medical School, “it does not imply that UV is actually good for you. . . . Across the board, for humanity, UV really is dangerous.”

Wei Xiong of the University of Science and Technology of China who led the research did not set out to investigate the effects of UV light on the brain or the skin-brain connection. He stumbled upon his initial finding “almost accidentally,” he explains in an email to The Scientist. Xiong and his colleagues were using a mass spectrometry technique they had recently developed for analyzing the molecular contents of single neurons, when their results revealed the unexpected presence of urocanic acid—a little-known molecule produced in the skin in response to UV light.

“It was a surprise because we checked through all the literature and found no reports of the existence of this small molecule in the central nervous system,” writes Xiong.

With little information to go on, Xiong and his colleagues decided to see whether UV light could also boost levels of urocanic acid in the brain. They exposed shaved mice to a low-dose of UVB—responsible for sunburn in humans—for 2 hours, then performed mass spectrometry on the animals’ individual brain cells. Sure enough, levels of urocanic acid increased in neurons of the animals exposed to the light, but not in those of control animals.

Urocanic acid can absorb UV rays and, as a result, may be able to protect skin against the sun’s harmful effects. But in the liver and other peripheral tissues, the acid is also known to be an intermediate molecule generated in the metabolic pathway that converts histidine to glutamate. Given glutamate’s role in the brain as an excitatory neurotransmitter, Xiong and his colleagues were interested to test whether the observed UV-dependent increase in urocanic acid in neurons might be coupled with increased glutamate production. It was.

Next, the team showed that UV light enhanced electrical transmission between glutaminergic neurons in brain slices taken from animals exposed to UV, but not in those from control animals. This UV-induced effect was prevented when the researchers inhibited activity of the enzyme urocanase, which converts urocanic acid to glutamate, indicating that the acid was indeed the mediator of the UV-induced boost in glutaminergic activity.

Lastly, the team showed that mice exposed to UV performed better in motor learning and recognition memory tasks than their unexposed counterparts. And, as before, treating the animals with a urocanase inhibitor prevented the UV-induced improvements in learning and memory. Administering urocanic acid directly to animals not exposed to ultraviolet light also spurred similar learning and memory improvements to those achieved with UV exposure.

Whether the results obtained in mice, which are nocturnal and rarely see the sun, will hold true in humans is yet to be determined. But, Fisher says, if the results do hold, the finding that urocanic acid alone can enhance learning and memory might suggest “a way to utilize this information to benefit people without exposing them to the damaging effects of UV.”

H. Zhu et al., “Moderate UV exposure enhances learning and memory by promoting a novel glutamate biosynthetic pathway in the brain,” Cell, doi: 10.1016/j.cell.2018.04.014, 2018.

https://www.the-scientist.com/?articles.view/articleNo/54603/title/Could-a-Dose-of-Sunshine-Make-You-Smarter-/

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Ta’u Island’s residents live off a solar power and battery storage-enabled microgrid.

by Amelia Heathman

SolarCity was applauded when it announced its plans for solar roofs earlier this year. Now, it appears it is in the business of creating solar islands.

The island of Ta’u in American Samoa, more than 4,000 miles from the United States’ West Coast, now hosts a solar power and battery storage-enabled microgrid that can supply nearly 100 per cent of the island’s power needs from renewable energy.

The microgrid is made up of 1.4 megawatts of solar generation capacity from SolarCity and Tesla and six-megawatt hours of battery storage from 60 Tesla Powerpacks. The whole thing took just a year to implement.

Due to the remote nature of the island, its citizens were used to constant power rationing, outages and a high dependency on diesel generators. The installation of the microgrid, however, provides a cost-saving alternative to diesel, and the island’s core services such as the local hospital, schools and police stations don’t have to worry about outages or rationing anymore.

“It’s always sunny out here, and harvesting that energy from the sun will make me sleep a lot more comfortably at night, just knowing I’ll be able to serve my customers,” said Keith Ahsoon, a local resident whose family owns one of the food stores on the island.

The power from the new Ta’u microgrid provides energy independence for the nearly 600 residents of the island. The battery system also allows the residents to use stored solar energy at night, meaning energy will always be available. As well as providing energy, the project will allow the island to significantly save on energy costs and offset the use of more than 109,500 gallons of diesel per year.

With concerns over climate change and the effects the heavy use of fossil fuels are having on the planet, more initiatives are taking off to prove the power of solar energy, whether it is SolarCity fueling an entire island or Bertrand Piccard’s Solar Impulse plane flying around the world on only solar energy.

Obviously Ta’u island’s location off the West Coast means it is in a prime location to harness the Sun’s energy, which wouldn’t necessarily work in the UK. Having said that, this is an exciting way to show where the future of solar energy could take us if it was amplified on a larger scale.

The project was funded by the American Samoa Economic Development Authority, the Environmental Protection Agency and the Department of Interior, whilst the microgrid is operated by the American Samoa Power Authority.

http://www.wired.co.uk/article/island-tau-solar-energy-solarcity

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.

By James Griffiths

Astronomers have discovered a planet with three suns, where an observer would experience either constant daylight or triple sunrises and sunsets depending on the seasons, which last longer than a human lifetime.

The planet, HD 131399Ab, is the first discovered in a stable orbit in a triple-star system; previously, it had been assumed that the unstable gravity would result in any planet being quickly flung out.

“If the planet was further away from the most massive star in the system, it would be kicked out of the system,” Daniel Apai of the University of Arizona said in a statement.

“Our computer simulations have shown that this type of orbit can be stable, but if you change things around just a little bit, it can become unstable very quickly.”

Kevin Wagner, who discovered the planet and led follow-up observations, said that “for about half of the planet’s orbit, which lasts 550 Earth years, three stars are visible in the sky.”

“It is not clear how this planet ended up on its wide orbit in this extreme system, and we can’t say yet what this means for our broader understanding of the types of planetary systems, but it shows that there is more variety out there than many would have deemed possible.”

The planet — reminiscent of Luke Skywalker’s twin-starred homeworld of Tatooine in “Star Wars” — is located in the Centaurus constellation, about 320 light-years from Earth.

It was found using the SPHERE instrument on the European Southern Observatory’s Very Large Telescope, which is sensitive to infrared light, allowing it to detect the heat signatures of young planets.

About 16 million years old, HD 131399Ab is one of the youngest exoplanets discovered to date, the observatory said in a statement.

By comparison, Earth is about 4.5 billion years old.

With an average temperature of about 580 degrees Celsius (1,076 degrees Fahrenheit) and an estimated mass of four Jupiters, it is also one of the coldest and smallest directly imaged exoplanets.

“HD 131399Ab is one of the few exoplanets that have been directly imaged, and it’s the first one in such an interesting dynamical configuration,” Apai said.

http://www.cnn.com/2016/07/07/health/planet-orbits-three-suns/index.html