A Blog devoted to progressive politics, environmental issues, LGBT issues, social justice, workers' rights, womens' rights, and, most importantly, Cats.

Tuesday, October 09, 2007

Science - Snippets From Science News

I cannot recommend Science News enough - it offers a roundup of everything that's happening in various scientific fields, top-notch writing, plenty of friendly links, stuff to get kids interested in science, and lists of books written on various scientific topics. And, have I mentioned it's well-written? A boon to those who dread ploughing through endless jargon and dry-as-dust opining. Thanks to them, I've expanded my science library hugely, over the past decade, and have reverted to thoroughly enjoying subjects as diverse as astronomy, nanotechnology, medicine, and paleontology that once thrilled my young mind, but eventually fell off the horizon as time grew short and work grew oppressive.

Note: Not all articles are available at their Web site, without a subscription. But the subscription is well worth the cost - especially if you want to interest your sprogs in science.

Here's my roundup of snippets from Vol. 168:

Possible cure for Parkinsons? Scientists are looking at the possibility of using stem cells as pumps for delivering drugs. Parkinson's disease results from the malfunction of brain cells responsible for producing dopamine. As these cells die, brain function that relies on dopamine is increasingly affected. A protein called glial-cell line-derived neurotrophic factor (GDNF) can protect dopamine-producing cells. However, the protein cannot cross the blood-brain barrier, so injections of the protein do not affect the brain. Neuroscientist Allison Ebert of the University of Wisconsin-Madison is working with neuroscientist Clive Svendsen and others to find a new way of transporting GDNF to dopamine-producing cells. They have added extra copies of the gene that makes GDNF to neural-progenitor stem cells that make small quantities of GDNF. When these cells are injected into the brains of rats, they integrate into brain tissue and appear to protect the dopamine-producing cells. Caveat: Neurobiologist Don M. Gash of the University of Kentucky, Lexington, points out that these cells cannot be regulated, unlike artificial pumps that are used to supply GDNF. Overproduction or underproduction of dopamine can both lead to adverse effects.

Air pollution combined with a high fat intake raises the risk of clogged arteries and resulting heart disease and strokes. Chen Lung Chi of New York University School of Medicine in Tuxedo collaborated with other scientists to show that mice genetically engineered to be susceptible to developing cholestrol plaques on their arteries, if exposed to polluted air combined with a high fat diet were nearly twice as likely to develop such plaque than mice on a high-fat diet but breathing clean air. A normal diet combined with clean air reduced plaque even further. The study hints that air pollution might accelerate plaque formation even without high-fat diet, says Michael T. Kleinman of the University of California at Irvine. The implications for people are grave, as those most likely to live in polluted neighbourhoods are also more likely to consume a diet of processed or fast food, which tends to be very high in fat.

Katarina LeBlanc of the Karolinska Institute of Stockholm has shown that mesenchymal stem cells, which normally turn into cells that produce bone, cartilage, or fat, can turn off the immune system, dampening inflammation which might result in GvHD (graft-versus-host disease, which can occur when blood-making stem cells are transferred from a healthy person's bone marrow to a person with an aggressive blood cancer). As a result of their inflammation-fighting properties, mesenchymal stem cells might be effective against autoimmune disorders, according to LeBlanc.

Scientists in England and Germany have found a way to create a new type of fuel cell - by stripping electrons from hydrogen molecules and adding them to oxygen atoms and hydrogen ions. The result? Water plus electric current. According to Fraser A. Armstrong of the University of Oxford in England, the transfer occurs in an atypical manner. Typically, microbes in oxygen-depleted mud use hydrogenases (enzymes) to split hydrogen molecules and use their electrons for energy. This is known as hydrogen oxidation. In fuel cells, this splitting and commandeering is carried out by platinum or other rare and expensive metals. However, the hydrogenases contained in microbes do not contain exotic metals, relying on iron and nickel, for example, to carry out their task. Caveat: oxygen disables the molecules - and most fuel cells have to work in ordinary air, which is largely oxygen and nitrogen. However, Ralstonia eutropha, a soil bacterium, has a hydrogenase that is more tolerant of oxygen. Armstrong's team genetically engineered R. eutropha to mass-produce the hydrogenase, then harvested the molecules, coated a graphic electrode with them, and used the electrode to build a fuel cell. Although Armstrong does not believe that R. eutropha's enzyme will be the ultimate choice of fuel cell makers, Marcetta Y. Darensbourg of Texas A&M University in College Station thinks his research could help other researchers develop fuel cells and hydrogen-generation devices based on cheap and abundant metals.

Neurologist Maurizio Corbetta of Washington University School of Medicine in St. Louis, working with several colleagues, has found that structures on both sides of the brain are responsible for maintaining visual attention. Thus, stroke patients who have suffered damage to the attention areas of the right brain often show hyperactivity in intact left-brain attention structures. Such patients focus their visual attention primarily to the right and display various fors of left-side neglect, such as failing to notice or eat food on the left half of a plate and behaving as if they did not have a left arm. Symptoms of this disorder, dubbed spatial neglect, affects up to 5 million worldwide. Though most severe in the weeks following a stroke, they can last for more than a year. Shades of Oliver Sacks' "The Man Who Mistook His Wife For A Hat"!

Beatrice de Gelder and her colleagues report that a study they performed to determine how people read emotions in others indicates that subtle body language cues that conflict with facial expressions can confuse subjects. Although participants were told to study only the faces and ignore the body language, their accuracy in determining emotion was 64 per cent when the facial expression and body posture were incongruent, and 81 per cent when facial expression was shown without body posture.

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