Brain tumors are the most common solid tumors of childhood, and pilocytic astrocytomas (PA) are the most common central nervous system tumor in 5 to 19 year olds. Little is known about the genetic alterations underlying their development. Here, we describe a tandem duplication of f2 Mb at 7q34 occurring in 66% of PAs. This rearrangement, which was not observed in a series of 244 higher-grade astrocytomas, results in an in-frame fusion gene incorporating the kinase domain of the BRAF oncogene. We further show that the resulting fusion protein has constitutive BRAF kinase activity and is able to transform NIH3T3 cells. This is the first report of BRAF activation through rearrangement as a frequent feature in a sporadic tumor. The frequency and specificity of this change underline its potential both as a therapeutic target and as a diagnostic tool. [Cancer Res 2008;68(21):8673-7]

Microbial biofilms are communities of aggregated microbial cells embedded in a self-produced matrix of extracellular polymeric substances (EPS). Biofilms are recalcitrant to extreme environments, and can protect microorganisms from ultraviolet (UV) radiation, extreme temperature, extreme pH, high salinity, high pressure, poor nutrients, antibiotics, etc., by acting as “protective clothing”. In recent years, research works on biofilms have been mainly focused on biofilm-associated infections and strategies for combating microbial biofilms. In this review, we focus instead on the contemporary perspectives of biofilm formation in extreme environments, and describe the fundamental roles of biofilm in protecting microbial exposure to extreme environmental stresses and the regulatory factors involved in biofilm formation. Understanding the mechanisms of biofilm formation in extreme environments is essential for the employment of beneficial microorganisms and prevention of harmful microorganisms.

Ultrasmall molybdenum sulfide nanoparticles with diameters of 1.47 AE 0.16 nm were fabricated from bulk MoS 2 by a combination of ultrasonication and centrifugation. The nanoparticles were then assembled on an Au surface to form a film with high electrocatalytic activity for hydrogen evolution reaction (HER). A Tafel slope of 69 mV per decade was measured for this film and the onset potential was estimated to be À0.09 V. The small loading (1.03 mg cm À2 ) and the high current density (0.92 mA cm À2 at h ¼ 0.15 V) demonstrated extremely high catalytic efficiency. X-ray photoelectron spectroscopic results revealed that the assembled nanoparticle film was sulfur enriched with abundant S edges and a structural rearrangement of the S rich particles might occur during the self-assembly process, resulting in significantly enhanced electrocatalytic activity for HER. Electrochemical impedance measurements suggested that the assembling process optimized the conductivity of the nanoparticle film, which contributed to the enhanced HER catalytic activity. Our research has provided a new way to synthesize active molybdenum sulfide nanoparticles for HER and a new approach to achieve enrichment of S edges on molybdenum sulfide, which might have potential use not only for electrocatalytic HER, but also for photoelectrocatalytic HER and plasmon-enhanced water splitting. Broader contextHydrogen produced by the water splitting process could potentially address the needs for the sustainable production of fuels in a manner that is renewable and carbon-free. However, cheap catalysts are required to overcome the large overpotential for hydrogen evolution reaction (HER) in an affordable manner. Recent studies have shown that sulfur edges of MoS 2 are quite active for HER. As a result, much effort has been focused on trying to acquire MoS 2 or MoS x nanomaterials with a plethora of sulfur edges. Here, we demonstrate a novel approach for synthesizing monodispersed molybdenum sulde nanoparticles with ultrasmall diameters and a new strategy for achieving enrichment of active S edges on molybdenum suldes by exploiting the covalent bonding of the nanocatalysts with the underlying gold electrode. The work is benecial not only for the design of highly efficient molybdenum sulde based HER catalysts but also for the synthesis of new catalysts for photoelectrocatalytic HER and plasmon-enhanced water splitting.

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FT-INTERACTING PROTEIN 1 is a novel protein that is involved in transporting florigen, a long-known mobile signal that induces flowering in plants in response to day length, from companion cells to sieve elements in the phloem of Arabidopsis.