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Prof. explains blue skin condition



The phenomenon of skin turning blue has been associated with the consumption of silver for years, but the connection between the color and the element was never clear until now. Brown professors have figured out the process underlying this rare condition known as argyria, according to a University press release. Their results were published in the journal ACS Nano earlier this month. 


To investigate how silver operates in the body, Professor of Engineering Robert Hurt and his team of Brown colleagues artificially recreated environments equivalent to the stomach, skin and bloodstream, according to the release. They then observed silver nanoparticles in these three areas. 


In an acidic human stomach, silver becomes a positively charged salt ion. Salt ions can easily be absorbed into the bloodstream and are eventually taken up by the skin. Once exposed to light, the silver salt in the skin gains an electron and becomes raw silver once more. This final step tints the skin blue, the researchers found.


The discovery was made when Hurt and his team shined a light on collagen gel, the skin equivalent, containing silver ions. 


Before this study, there was a fear that silver nanoparticles posed a "unique health threat" different from other forms of ingested silver, according to the press release. This study shows that silver nanoparticles have the same effect on the body as larger portions of ingested silver, just on a smaller scale, according to the release.



Prof. outlines infection prevention plan for astronauts



A spaceship provides the ideal environment for infectious agents to thrive, according to a literature review conducted by Leonard Mermel, professor of medicine and medical director of the epidemiology and infection control department at Rhode Island Hospital.


Space's lack of gravity ensures that germs remain airborne for longer periods of time, increasing the chance that astronauts will inhale them, Mermel said in a University press release. Air filtration is difficult due to electrical power constraints, and astronauts are prohibited from using hygiene products that could release hazardous vapors into the constantly recycling airflow.  NASA reports that 29 infectious disease cases have occurred among 742 astronauts across 106 space missions.


While astronauts are currently vaccinated and screened for select diseases before takeoff, Mermel recommended enhancing the vaccination portfolio and expanding pre-flight screening procedures, such as stool screening for salmonella, according to the press release. In addition, high-tech air filtration would be beneficial and spaceship toilet and sink handles could be replaced with foot pedals. Food presents a unique challenge because it is home to both potentially harmful pathogens and gut-benefitting bacteria, the release said.


Future space infection-fighting measures should include a rethinking of the diagnostic tests brought on board and the discovery of an effective antimicrobial coating and hand sanitizer for use aboard the space shuttle, Mermel said in the press release.           



U. chemists make hydrogen fuel tech progress



Hydrogen fuel cell technology may become a more economically viable alternative power source thanks to Brown chemists. The team has created a new hydrogen fuel cell catalyst that is a cheaper and more durable option than the widely used platinum catalyst, according to a University press release.


"(Platinum) is very expensive and has a very limited supply," said Shouheng Sun PhD'96, professor of chemistry, who worked with students to develop the new catalyst - a graphene sheet made of honeycombed carbon atoms covered with cobalt and cobalt-oxide nanoparticles. This material - the first catalyst that performs as effectively as platinum and is not made from a precious metal - triggers the oxygen-reduction reaction that makes a hydrogen fuel cell run.


While Sun's material is slightly slower than platinum at catalyzing the initial reaction, once the reaction is off and running, the cobalt catalyst actually reduces oxygen at a faster rate. Another perk is cobalt's abundance and low cost, the press release said.


"Right now, it's comparable to platinum ... but it's not ready for use yet. We still need to do more tests," Sun said, according to the release. But the new catalyst offers great promise in transforming hydrogen fuel cell technology from a lab bench denizen into a real-world power source. 


 



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