Review of particle physics Hagiwara, K; Nakamura, K; Amsler, C ...
Physical review. D, Particles and fields,
07/2002, Letnik:
66, Številka:
1
Journal Article
Recenzirano
This biennial Review summarizes much of Particle Physics Using data from previous editions, plus 2205 new measurements from 667 papers, we list, evaluate, and average measured properties of gauge ...bosons, leptons, quarks, mesons, and baryons We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles All the particle properties and search limits are listed in Summary Tables We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics This edition features expanded coverage of CP violation in B mesons and of neutrino oscillations For the first time we cover searches for evidence of extra dimensions (both in the particle listings and in a new review) Another new review is on Grand Unified Theories A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review All tables, listings, and reviews (and errata) are also available on the Particle Data Group website http //pdg 1b1 gov.
Crenarchaeota in Lake Michigan sediment MACGREGOR, B. J; MOSER, D. P; ALM, E. W ...
Applied and Environmental Microbiology,
03/1997, Letnik:
63, Številka:
3
Journal Article
Visual and verbal episodic memory deficits are putative endophenotypes for schizophrenia; however, the extent of any genetic overlap of these with schizophrenia is unclear. In this study, we set out ...to quantify the genetic and environmental contributions to variance in visual and verbal memory performance, and to quantify their genetic relationship with schizophrenia.
We applied bivariate genetic modelling to 280 twins in a classic twin study design, including monozygotic (MZ) and dizygotic (DZ) pairs concordant and discordant for schizophrenia, and healthy control twins. We assessed episodic memory using subtests of the Wechsler Memory Scale - Revised (WMS-R).
Genetic influences (i.e. heritability) contributed significantly to variance in immediate recall of both verbal memory and visual learning, and the delayed recall of verbal and visual memory. Liability to schizophrenia was associated with memory impairment, with evidence of significant phenotypic correlations between all episodic memory measures and schizophrenia. Genetic factors were the main source of the phenotypic correlations for immediate recall of visual learning material; both immediate and delayed recall of verbal memory; and delayed recall of visual memory that, for example, shared genetic variance with schizophrenia, which accounted for 88% of the phenotypic correlation (rph=0.41) between the two.
Verbal memory and visual learning and memory are moderately heritable, share a genetic overlap with schizophrenia and are valid endophenotypes for the condition. The inclusion of these endophenotypes in genetic association studies may improve the power to detect susceptibility genes for schizophrenia.
Mineralization of organic matter in anoxic environments relies on the cooperative activities of hydrogen producers and consumers linked by interspecies electron transfer in syntrophic consortia that ...may include sulfate-reducing species (e.g., Desulfovibrio). Physiological differences and various gene repertoires implicated in syntrophic metabolism among Desulfovibrio species suggest considerable variation in the biochemical basis of syntrophy. In this study, comparative transcriptional and mutant analyses of Desulfovibrio alaskensis strain G20 and Desulfovibrio vulgaris strain Hildenborough growing syntrophically with Methanococcus maripaludis on lactate were used to develop new and revised models for their alternative electron transfer and energy conservation systems. Lactate oxidation by strain G20 generates a reduced thiol-disulfide redox pair(s) and ferredoxin that are energetically coupled to H+/CO2 reduction by periplasmic formate dehydrogenase and hydrogenase via a flavin-based reverse electron bifurcation process (electron confurcation) and a menaquinone (MQ) redox loop-mediated reverse electron flow involving the membrane-bound Qmo and Qrc complexes. In contrast, strain Hildenborough uses a larger number of cytoplasmic and periplasmic proteins linked in three intertwining pathways to couple H+ reduction to lactate oxidation. The faster growth of strain G20 in coculture is associated with a kinetic advantage conferred by the Qmo-MQ-Qrc loop as an electron transfer system that permits higher lactate oxidation rates under elevated hydrogen levels (thereby enhancing methanogenic growth) and use of formate as the main electron-exchange mediator (>70% electron flux), as opposed to the primarily hydrogen-based exchange by strain Hildenborough. This study further demonstrates the absence of a conserved gene core in Desulfovibrio that would determine the ability for a syntrophic lifestyle.
RNA editing critically regulates neurodevelopment and normal neuronal function. The global landscape of RNA editing was surveyed across 364 schizophrenia cases and 383 control postmortem brain ...samples from the CommonMind Consortium, comprising two regions: dorsolateral prefrontal cortex and anterior cingulate cortex. In schizophrenia, RNA editing sites in genes encoding AMPA-type glutamate receptors and postsynaptic density proteins were less edited, whereas those encoding translation initiation machinery were edited more. These sites replicate between brain regions, map to 3'-untranslated regions and intronic regions, share common sequence motifs and overlap with binding sites for RNA-binding proteins crucial for neurodevelopment. These findings cross-validate in hundreds of non-overlapping dorsolateral prefrontal cortex samples. Furthermore, ~30% of RNA editing sites associate with cis-regulatory variants (editing quantitative trait loci or edQTLs). Fine-mapping edQTLs with schizophrenia risk loci revealed co-localization of eleven edQTLs with six loci. The findings demonstrate widespread altered RNA editing in schizophrenia and its genetic regulation, and suggest a causal and mechanistic role of RNA editing in schizophrenia neuropathology.
Meiotic exchange occurs preferentially between homologous chromatids, in contrast to mitotic recombination, which occurs primarily between sister chromatids. To identify functions that direct meiotic ...recombination events to homologues, we screened for mutants exhibiting an increase in meiotic unequal sister-chromatid recombination (SCR). The msc (meiotic sister-chromatid recombination) mutants were quantified in spo13 meiosis with respect to meiotic unequal SCR frequency, disome segregation pattern, sporulation frequency, and spore viability. Analysis of the msc mutants according to these criteria defines three classes. Mutants with a class I phenotype identified new alleles of the meiosis-specific genes RED1 and MEK1, the DNA damage checkpoint genes RAD24 and MEC3, and a previously unknown gene, MSC6. The genes RED1, MEK1, RAD24, RAD17, and MEC1 are required for meiotic prophase arrest induced by a dmc1 mutation, which defines a meiotic recombination checkpoint. Meiotic unequal SCR was also elevated in a rad17 mutant. Our observation that meiotic unequal SCR is elevated in meiotic recombination checkpoint mutants suggests that, in addition to their proposed monitoring function, these checkpoint genes function to direct meiotic recombination events to homologues. The mutants in class II, including a dmc1 mutant, confer a dominant meiotic lethal phenotype in diploid SPO13 meiosis in our strain background, and they identify alleles of UBR1, INP52, BUD3, PET122, ELA1, and MSC1-MSC3. These results suggest that DMC1 functions to bias the repair of meiosis-specific double-strand breaks to homologues. We hypothesize that the genes identified by the class II mutants function in or are regulators of the DMC1-promoted interhomologue recombination pathway. Class III mutants may be elevated for rates of both SCR and homologue exchange.
The physicomechanical properties and structure of superhard cBN–Ti
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5
–Al materials were studied. The materials were sintered under a pressure of 7.7 GPa within a broad range of temperatures ...(1600–2450°C). The formation of a dense material with high physicomechanical properties was found at a sintetring temperature of 1800°C. A further increase in the sintering temperature had a negligible effect on the properties of sintered materials. The formation of titanium diboride and a slight increase in the unit cell parameters of Ti
4
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5
were revealed at sintering temperatures above 2000°C. According to X-ray diffraction analysis, this might be due to the diffusion of Al into the Ti
4
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5
lattice. Cutting performance in the longitudinal turning of stainless steel AISI 316L correlated with the sintering temperature, and the average tool wear was ranged within 60–82 µm.
Little is known about the effects of common cooking processes on cocoa flavanols. Antioxidant activity, total polyphenols (TP), flavanol monomers, and procyanidin oligomers were determined in ...chocolate frosting, a hot cocoa drink, chocolate cookies, and chocolate cake made with natural cocoa powder. Recoveries of antioxidant activity, TP, flavanol monomers, and procyanidins ranged from 86% to over 100% in the chocolate frosting, hot cocoa drink, and chocolate cookies. Losses were greatest in the chocolate cake with recoveries ranging from 5% for epicatechin to 54% for antioxidant activity. The causes of losses in baked chocolate cakes were investigated by exchanging baking soda with baking powder or combinations of the 2 leavening agents. Use of baking soda as a leavening agent was associated with increased pH and darkening color of cakes. Losses of antioxidant activity, TP, flavanol monomers, and procyanidins were associated with an increased extractable pH of the baked cakes. Chocolate cakes made with baking powder for leavening resulted in an average extractable pH of 6.2 with essentially complete retention of antioxidant activity and flavanol content, but with reduced cake heights and lighter cake color. Commercially available chocolate cake mixes had final pHs above 8.3 and contained no detectable monomeric flavanols after baking. These results suggest that baking soda causes an increase in pH and subsequent destruction of flavanol compounds and antioxidant activity. Use of an appropriate leavening agent to moderate the final cake pH to approximately 7.25 or less results in both good leavening and preservation of cocoa flavanols and procyanidins.
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