Tag Archives: oxidation

Neu: Umweltfreundliche chemische Reaktion verschwendet keine Atome

In der Arbeitsgruppe von Nuno Maulide, Chemiker an der Universität Wien, wurde eine neue chemische Synthese für α-arylierte Carbonylverbindungen entwickelt. Vertreter dieser Substanzklasse zeigen interessante biologische und pharmakologische Eigenschaften und kommen z.B. bei entzündungshemmenden Medikamenten zur Anwendung. Die neue Technik, mit der sich solche Carbonylverbindungen einfach, effizient und umweltfreundlich – ohne Verschwendung von Atomen – herstellen lassen, erregt in der Wissenschaft derzeit hohe Aufmerksamkeit. Die Publikation im Fachmagazin “Angewandte Chemie” wurde von der Redaktion als sehr wichtig eingestuft.

Vom zufälligen Ergebnis zum rationalen Design
In der organischen Chemie gibt es nach wie vor Überraschungen, z.B. wenn neue Eigenschaften bei Stoffen und Reaktionen entdeckt werden. Beispielsweise eine neue Reaktivität, also die Fähigkeit eines Stoffes, eine chemische Reaktion einzugehen, liefert ein tieferes Verständnis der an der Reaktion beteiligten Faktoren. ChemikerInnen können im Idealfall darauf aufbauend neue Transformationen entwickeln. (more…)

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A Window into Europa’s Ocean Right at the Surface

If you could lick the surface of Jupiter’s icy moon Europa, you would actually be sampling a bit of the ocean beneath. A new paper by Mike Brown, an astronomer at the California Institute of Technology in Pasadena, Calif., and Kevin Hand from NASA’s Jet Propulsion Laboratory, also in Pasadena, details the strongest evidence yet that salty water from the vast liquid ocean beneath Europa’s frozen exterior actually makes its way to the surface.

The finding, based on some of the best data of its kind since NASA’s Galileo mission (1989 to 2003) to study Jupiter and its moons, suggests there is a chemical exchange between the ocean and surface, making the ocean a richer chemical environment. The work is described in a paper that has been accepted for publication in the Astronomical Journal. (more…)

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Vitamin D, Omega-3 May Help Clear Amyloid Plaques Found in Alzheimer’s

A team of academic researchers has pinpointed how vitamin D3 and omega-3 fatty acids may enhance the immune system’s ability to clear the brain of amyloid plaques, one of the hallmarks of Alzheimer’s disease.

In a small pilot study published in the Feb. 5 issue of the Journal of Alzheimer’s Disease, the scientists identified key genes and signaling networks regulated by vitamin D3 and the omega-3 fatty acid DHA (docosahexaenoic acid) that may help control inflammation and improve plaque clearance. (more…)

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Large Bacterial Population Colonized Land 2.75 Billion Years Ago

There is evidence that some microbial life had migrated from the Earth’s oceans to land by 2.75 billion years ago, though many scientists believe such land-based life was limited because the ozone layer that shields against ultraviolet radiation did not form until hundreds of millions years later.

But new research from the University of Washington suggests that early microbes might have been widespread on land, producing oxygen and weathering pyrite, an iron sulfide mineral, which released sulfur and molybdenum into the oceans. (more…)

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UMD Finding May Hold Key to Gaia Theory of Earth as Living Organism

Discovery ultimately could lead to better climate understanding and prediction

COLLEGE PARK, Md. Is Earth really a sort of giant living organism as the Gaia hypothesis predicts? A new discovery made at the University of Maryland may provide a key to answering this question. This key of sulfur could allow scientists to unlock heretofore hidden interactions between ocean organisms, atmosphere, and land — interactions that might provide evidence supporting this famous theory.

The Gaia hypothesis — first articulated by James Lovelock and Lynn Margulis in the 1970s — holds that Earth’s physical and biological processes are inextricably connected to form a self-regulating, essentially sentient, system.

One of the early predictions of this hypothesis was that there should be a sulfur compound made by organisms in the oceans that was stable enough against oxidation in water to allow its transfer to the air. Either the sulfur compound itself, or its atmospheric oxidation product, would have to return sulfur from the sea to the land surfaces. The most likely candidate for this role was deemed to be dimethylsulfide. (more…)

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Touch of Gold Improves Nanoparticle Fuel-Cell Reactions

Chemists at Brown University have created a triple-headed metallic nanoparticle that reportedly performs better and lasts longer than any other nanoparticle catalyst studied in fuel-cell reactions. The key is the addition of gold: It yields a more uniform crystal structure while removing carbon monoxide from the reaction. Results published in the Journal of the American Chemical Society.

PROVIDENCE, R.I. [Brown University] — Advances in fuel-cell technology have been stymied by the inadequacy of metals studied as catalysts. The drawback to platinum, other than cost, is that it absorbs carbon monoxide in reactions involving fuel cells powered by organic materials like formic acid. A more recently tested metal, palladium, breaks down over time. (more…)

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Upper Atmosphere Facilitates Changes That Let Mercury Enter Food Chain

Humans pump thousands of tons of vapor from the metallic element mercury into the atmosphere each year, and it can remain suspended for long periods before being changed into a form that is easily removed from the atmosphere.

New research shows that the upper troposphere and lower stratosphere work to transform elemental mercury into oxidized mercury, which can easily be deposited into aquatic ecosystems and ultimately enter the food chain. (more…)

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