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11.
Changing the L:D intensity ratio of a synchronizing dark regime leads to characteristic modulations of the activity pattern of Chiroptera species. These modulations fit the predictions of WEVER'S oscillator model. 相似文献
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Andrés E Askebjer P Bai X Barouch G Barwick SW Bay RC Becker KH Bergström L Bertrand D Bierenbaum D Biron A Booth J Botner O Bouchta A Boyce MM Carius S Chen A Chirkin D Conrad J Cooley J Costa CG Cowen DF Dailing J Dalberg E DeYoung T Desiati P Dewulf JP Doksus P Edsjö J Ekström P Erlandsson B Feser T Gaug M Goldschmidt A Goobar A Gray L Haase H Hallgren A Halzen F Hanson K Hardtke R He YD Hellwig M Heukenkamp H Hill GC Hulth PO Hundertmark S Jacobsen J Kandhadai V Karle A Kim J Koci B Köpke L 《Nature》2001,410(6827):441-443
Neutrinos are elementary particles that carry no electric charge and have little mass. As they interact only weakly with other particles, they can penetrate enormous amounts of matter, and therefore have the potential to directly convey astrophysical information from the edge of the Universe and from deep inside the most cataclysmic high-energy regions. The neutrino's great penetrating power, however, also makes this particle difficult to detect. Underground detectors have observed low-energy neutrinos from the Sun and a nearby supernova, as well as neutrinos generated in the Earth's atmosphere. But the very low fluxes of high-energy neutrinos from cosmic sources can be observed only by much larger, expandable detectors in, for example, deep water or ice. Here we report the detection of upwardly propagating atmospheric neutrinos by the ice-based Antarctic muon and neutrino detector array (AMANDA). These results establish a technology with which to build a kilometre-scale neutrino observatory necessary for astrophysical observations. 相似文献
13.
大亚湾核电站PRA项目组 《南华大学学报(自然科学版)》1999,(2)
大亚湾核电站的概率风险分析(PRA)项目于1998年12月通过了国际原子能机构(IAEA)的同行评审,IAEA专家对大亚湾核电站的PRA给予了充分的肯定,认为大亚湾核电站在PRA领域已建立了良好的基础,本文介绍了大亚湾核电站最新的一级概率风险分析结果. 相似文献
14.
Quesada V Conde L Villamor N Ordóñez GR Jares P Bassaganyas L Ramsay AJ Beà S Pinyol M Martínez-Trillos A López-Guerra M Colomer D Navarro A Baumann T Aymerich M Rozman M Delgado J Giné E Hernández JM González-Díaz M Puente DA Velasco G Freije JM Tubío JM Royo R Gelpí JL Orozco M Pisano DG Zamora J Vázquez M Valencia A Himmelbauer H Bayés M Heath S Gut M Gut I Estivill X López-Guillermo A Puente XS Campo E López-Otín C 《Nature genetics》2012,44(1):47-52
Here we perform whole-exome sequencing of samples from 105 individuals with chronic lymphocytic leukemia (CLL), the most frequent leukemia in adults in Western countries. We found 1,246 somatic mutations potentially affecting gene function and identified 78 genes with predicted functional alterations in more than one tumor sample. Among these genes, SF3B1, encoding a subunit of the spliceosomal U2 small nuclear ribonucleoprotein (snRNP), is somatically mutated in 9.7% of affected individuals. Further analysis in 279 individuals with CLL showed that SF3B1 mutations were associated with faster disease progression and poor overall survival. This work provides the first comprehensive catalog of somatic mutations in CLL with relevant clinical correlates and defines a large set of new genes that may drive the development of this common form of leukemia. The results reinforce the idea that targeting several well-known genetic pathways, including mRNA splicing, could be useful in the treatment of CLL and other malignancies. 相似文献
15.
Induction of vanadium accumulation and nuclear sequestration causing cell suicide in human Chang liver cells 总被引:1,自引:0,他引:1
K. H. Sit R. Paramanantham B. H. Bay K. P. Wong P. Thong F. Watt 《Cellular and molecular life sciences : CMLS》1996,52(8):778-785
Very little is known about the modulation of vanadium accumulation in cells, although this ultratrace element has long been seen as an essential nutrient in lower life forms, but not necessarily in humans where factors modulating cellular uptake of vanadium seem unclear. Using nuclear microscopy, which is capable of the direct evaluation of free and bound (total) elemental concentrations of single cells we show here that an NH4Cl acidification prepulse causes distinctive accumulation of vanadium (free and bound) in human Chang liver cells, concentrating particularly in the nucleus. Vanadium loaded with acidification but leaked away with realkalinization, suggests proton-dependent loading. Vanadyl(4), the oxidative state of intracellular vanadium ions, is known to be a potent source of hydroxyl free radicals (OH.). The high oxidative state of nuclei after induction of vanadyl(4) loading was shown by the redox indicator methylene blue, suggesting direct oxidative damage to nuclear DNA. Flow cytometric evaluation of cell cycle phase-specific DNA composition showed degradation of both 2N and 4N DNA phases in G1, S and G2/M cell cycle profiles to a solitary 1N DNA peak, in a dose-dependent manner, effective from micromolar vanadyl(4) levels. This trend was reproduced with microccocal nuclease digestion in a time response, supporting the notion of DNA fragmentation effects. Several other approaches confirmed fragmentation occurring in virtually all cells after 4 mM V(4) loading. Ultrastructural profiles showed various stages of autophagic autodigestion and well defined plasma membrane outlines, consistent with programmed cell death but not with necrotic cell death. Direct intranuclear oxidative damage seemed associated with the induction of mass suicide in these human Chang liver cells following vanadium loading and nuclear sequestration. 相似文献
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Cheung NS Choy MS Halliwell B Teo TS Bay BH Lee AY Qi RZ Koh VH Whiteman M Koay ES Chiu LL Zhu HJ Wong KP Beart PM Cheng HC 《Cellular and molecular life sciences : CMLS》2004,61(15):1926-1934
The tumor suppressor function of PTEN is attributed to its phospholipid phosphatase activity that
dephosphorylates the plasma membrane phosphatidylinositol-(3,4,5)-triphosphate
[PtdIns(3,4,5)P3]. Implicit in this notion is that PTEN needs to be targeted to the plasma
membrane to dephosphorylate PtdIns(3,4,5)P3. However, the recruitment of PTEN to the plasma
membrane is not fully understood. Here, we demonstrate PTEN accumulation in the detergent-insoluble fraction of
neuronal cells in response to treatment by the proteasome inhibitor lactacystin. First, lactacystin induces
apoptosis and the activation of caspase-3 in cultured cortical neurons. Second, PTEN undergoes proteolysis to
form a truncated 50-kDa form that lacks parts of its C-terminal tail. Third, the truncated PTEN is stably
associated with the detergent-insoluble fraction in which the plasma membrane marker protein flotillin-1 resides.
Taken together, our results suggest that truncation and accumulation of PTEN to the detergent-insoluble membrane
fraction are two events associated with the apoptotic signals of the proteasome inhibitor in cortical neurons.Received 24 March 2004; received after revision 26 May 2004; accepted 5 June 2004 相似文献