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Archive - Mar 27, 2011

Scientists Create Artificial Leaf

Researchers today (March 27, 2011) claimed one of the milestones in the drive for sustainable energy — development of the first practical artificial leaf. Speaking at the 241st National Meeting of the American Chemical Society, they described an advanced solar cell the size of a playing card that mimics the process of photosynthesis that green plants use to convert sunlight and water into energy. "A practical artificial leaf has been one of the Holy Grails of science for decades," said Dr. Daniel Nocera, who led the research team. "We believe we have done it. The artificial leaf shows particular promise as an inexpensive source of electricity for homes of the poor in developing countries. Our goal is to make each home its own power station," he said. "One can envision villages in India and Africa not long from now purchasing an affordable basic power system based on this technology." The device bears no resemblance to Mother Nature's counterparts on oaks, maples, and other green plants, which scientists have used as the model for their efforts to develop this new genre of solar cells. About the shape of a playing card but thinner, the device is fashioned from silicon, electronics and catalysts. Placed in a single gallon of water in bright sunlight, the device could produce enough electricity to supply a house in a developing country with electricity for a day, Dr. Nocera said. It does so by splitting water into its two components, hydrogen and oxygen. The hydrogen and oxygen gases would be stored in a fuel cell, which uses those two materials to produce electricity, located either on top of the house or beside it. Dr. Nocera, who is with the Massachusetts Institute of Technology, points out that the "artificial leaf" is not a new concept. The first artificial leaf was developed more than a decade ago by Dr. John Turner of the U.S.

Insights into Molecular Motor Inside DNA Repair Complex

Over the last years, two teams of researchers at The Scripps Research Institute have steadily built a model of how a powerful DNA repair complex works. Now, their latest discovery provides revolutionary insights into the way the molecular motor inside the complex functions – findings they say may have implications for treatment of disorders ranging from cancer to cystic fibrosis. In a paper published online on March 27, 2011, in Nature Structural & Molecular Biology, the scientists say that the complex's motor molecule, known as Rad50, is a surprisingly flexible protein that can change shape and even rotate depending on the task at hand. The finding solves the long-standing mystery of how a single protein complex known as MRN (Mre11-Rad50-Nbs1) can repair DNA in a number of different, and tricky, ways that seem impossible for "standard issue" proteins to do, said team leaders Scripps Research Professor John Tainer and Scripps Research Professor Paul Russell, who also collaborated with members of the Lawrence Berkeley National Laboratory on the study. The scientists said the finding also provides a critical insight into the ABC-ATPase superfamily of molecular motors, of which Rad50 is a member. "Rad50 and its brethren proteins in this superfamily are biology's general motors," said Dr. Tainer, "and if we know how they work, we might be able to control biological outcomes when we need to." For example, knowing that Rad50 changes its contour to perform a function suggests it might be possible to therapeutically target unique elements in that specific conformation. "There could be a new generation of drugs that are designed not against an active site, like most drugs now (an approach that can cause side effects), but against the shape the protein needs to be in to work," Dr. Tainer said. Dr.

Walnut Is Top Nut for Antioxidants

A new scientific study positions walnuts in the No. 1 slot in a family of foods that lays claim to being among Mother Nature's most nearly perfect packaged foods: Tree and ground nuts. In a report presented on March 27, 2011, at the 241st National Meeting & Exposition of the American Chemical Society, scientists presented an analysis showing that walnuts have a combination of more healthful antioxidants and higher-quality antioxidants than any other nut. "Walnuts rank above peanuts, almonds, pecans, pistachios and other nuts," said Dr. Joe Vinson, who did the analysis. "A handful of walnuts contains almost twice as much antioxidants as an equivalent amount of any other commonly consumed nut. But unfortunately, people don't eat a lot of them. This study suggests that consumers should eat more walnuts as part of a healthy diet." Vinson noted that nuts in general have an unusual combination of nutritional benefits — in addition to those antioxidants — wrapped into a convenient and inexpensive package. Nuts, for instance, contain plenty of high-quality protein that can substitute for meat; vitamins and minerals; dietary fiber; and are dairy- and gluten-free. Years of research by scientists around the world link regular consumption of small amounts of nuts or peanut butter with decreased risk of heart disease, certain kinds of cancer, gallstones, Type 2 diabetes, and other health problems. Despite all the previous research, scientists until now had not compared both the amount and quality of antioxidants found in different nuts, Dr. Vinson said. He filled that knowledge gap by analyzing antioxidants in nine different types of nuts: walnuts, almonds, peanuts, pistachios, hazelnuts, Brazil nuts, cashews, macadamias, and pecans. Walnuts had the highest levels of antioxidants. Dr.

Scientists Unravel Key Gene Processes Driving Acute Myeloid Leukemia

Researchers have described how the most common gene mutation found in acute myeloid leukemia starts the process of cancer development and how it can cooperate with a well-defined group of other mutations to cause full-blown leukemia. The researchers suggest that three critical steps are required to transform normal blood cells into leukemic ones, each subverting a different cellular process. By charting the route towards cancer, the study identifies processes that might serve as targets for new treatments to halt the cancer's development in its tracks and even reverse it. Acute myeloid leukemia is a rare but devastating disease, which can take hold in a matter of just days or weeks. Every year, 2,000 adults in the UK are diagnosed with acute myeloid leukaemia: only about three in ten adults survive for five years. In recent years researchers have identified a number of genes involved in the development of acute myeloid leukemia. The most common is NPM1, a gene with many known functions. The new research shows that mutation in NPM1 is a key event in the development of a large proportion of cases of acute myeloid leukemia and that it exerts its effect by helping cells to self-renew, a process that can be thought of as the first step towards leukemia. The team also identified two subsequent events that are required to cooperate with NPM1 to drive cells to become cancerous. The new work was published online on March 27, 2011, in Nature Genetics. "We have used targeted gene disruption to look at the way acute myeloid leukemia develops in mice," says Dr George Vassiliou, Consultant Haematologist, cancer researcher and first author on the study from the Wellcome Trust Sanger Institute, "and have found critical steps that take place when the cancer develops.

MS May Involve Previously Unknown Type of Reversible Axonal Degeneration

The immune system recognizes and neutralizes or destroys toxins and foreign pathogens that have gained access to the body. Autoimmune diseases result when the system attacks the body's own tissues instead. One of the most common examples is multiple sclerosis (MS). MS is a serious condition in which nerve-cell projections, or axons, in the brain and the spinal cord are destroyed as a result of misdirected inflammatory reactions. It is often characterized by an unpredictable course, with periods of remission being interrupted by episodes of relapse. A team of researchers led by LMU Munich Professor Martin Kerschensteiner of the Medical Center of the University of Munich and Professor Thomas Misgeld from the Technical University of Munich has now been able to explain how the damage is inflicted. The results reveal that the inflammatory reaction can induce a previously unknown type of axonal degeneration, which they call "focal axonal degeneration" (FAD). In an animal model of MS, this process is reversible if it is recognized and treated early, so the researchers believe that it could serve as a potential target for therapeutic intervention. "Development of an effective treatment will be a long-term project," cautioned Dr. Kerschensteiner. "As yet, we only have a superficial understanding of the underlying molecular mechanisms and, of course, finding effective therapies will require time-consuming screens and extensive trials of drug candidates." The new work was published online on March 27, 2011, in Nature Medicine. Multiple sclerosis is a common and, in many cases seriously disabling, autoimmune disease that can lead to the disturbance or loss of sensory function, voluntary movement, vision and bladder control.