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1.
We developed a series of interrelated locus-specific databases to store all published and unpublished genetic variation related to hemoglobinopathies and thalassemia and implemented microattribution to encourage submission of unpublished observations of genetic variation to these public repositories. A total of 1,941 unique genetic variants in 37 genes, encoding globins and other erythroid proteins, are currently documented in these databases, with reciprocal attribution of microcitations to data contributors. Our project provides the first example of implementing microattribution to incentivise submission of all known genetic variation in a defined system. It has demonstrably increased the reporting of human variants, leading to a comprehensive online resource for systematically describing human genetic variation in the globin genes and other genes contributing to hemoglobinopathies and thalassemias. The principles established here will serve as a model for other systems and for the analysis of other common and/or complex human genetic diseases.  相似文献   
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Basal-like breast cancer (BBC) is a subtype of breast cancer with poor prognosis. Inherited mutations of BRCA1, a cancer susceptibility gene involved in double-strand DNA break (DSB) repair, lead to breast cancers that are nearly always of the BBC subtype; however, the precise molecular lesions and oncogenic consequences of BRCA1 dysfunction are poorly understood. Here we show that heterozygous inactivation of the tumor suppressor gene Pten leads to the formation of basal-like mammary tumors in mice, and that loss of PTEN expression is significantly associated with the BBC subtype in human sporadic and BRCA1-associated hereditary breast cancers. In addition, we identify frequent gross PTEN mutations, involving intragenic chromosome breaks, inversions, deletions and micro copy number aberrations, specifically in BRCA1-deficient tumors. These data provide an example of a specific and recurrent oncogenic consequence of BRCA1-dependent dysfunction in DNA repair and provide insight into the pathogenesis of BBC with therapeutic implications. These findings also argue that obtaining an accurate census of genes mutated in cancer will require a systematic examination for gross gene rearrangements, particularly in tumors with deficient DSB repair.  相似文献   
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Cher.  AA 《世界科学》1989,11(11):11-14
40年前A.爱因斯坦给M.玻恩的一封信中写道,“上帝不玩骰子。”爱因斯坦是始终反对量子论的概率解释的,他不倦地探索着与经典力学更为直接的类比,即考虑没有概率不定性的确定过程。如今,40年过去了,没有人会惊讶:甚至在一个经典哈密顿动力系统中也存在着(chas)在物理客体规则运动的领域内,在没有人预期会有的地方冒出  相似文献   
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Borg LE  Connelly JN  Boyet M  Carlson RW 《Nature》2011,477(7362):70-72
Chemical evolution of planetary bodies, ranging from asteroids to the large rocky planets, is thought to begin with differentiation through solidification of magma oceans many hundreds of kilometres in depth. The Earth's Moon is the archetypical example of this type of differentiation. Evidence for a lunar magma ocean is derived largely from the widespread distribution, compositional and mineralogical characteristics, and ancient ages inferred for the ferroan anorthosite (FAN) suite of lunar crustal rocks. The FANs are considered to be primary lunar flotation-cumulate crust that crystallized in the latter stages of magma ocean solidification. According to this theory, FANs represent the oldest lunar crustal rock type. Attempts to date this rock suite have yielded ambiguous results, however, because individual isochron measurements are typically incompatible with the geochemical make-up of the samples, and have not been confirmed by additional isotopic systems. By making improvements to the standard isotopic techniques, we report here the age of crystallization of FAN 60025 using the (207)Pb-(206)Pb, (147)Sm-(143)Nd and (146)Sm-(142)Nd isotopic systems to be 4,360?±?3 million years. This extraordinarily young age requires that either the Moon solidified significantly later than most previous estimates or the long-held assumption that FANs are flotation cumulates of a primordial magma ocean is incorrect. If the latter is correct, then much of the lunar crust may have been produced by non-magma-ocean processes, such as serial magmatism.  相似文献   
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二甲基甲酰胺中Sm(Ⅲ)电化学性质及其合金膜研究   总被引:1,自引:0,他引:1  
通过循环伏安法研究二甲基甲酰胺中Sm(Ⅲ)在Pt上的电化学性质,表明Sm(Ⅲ)在Pt上的还原为不可逆反应,同时测得传递系数α=0.0289,扩散系数D0=1.288×10^-5cm^2·S^-1;通过塔菲尔曲线求得交换电流密度i0=1.596×10^-7A/cm^2;对Sm(Ⅲ)在Pt上离子成核机理研究表明,Sm(Ⅲ)在Pt电极上是按三维模式扩散控制下连续成核的;用恒电位法可以制得有金属光泽、附着力好、表面均匀致密的Sm-Ni-Co合金膜,与Ni-Co合金膜相比较结构性能有所提高.  相似文献   
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CD1d-lipid-antigen recognition by the semi-invariant NKT T-cell receptor   总被引:2,自引:0,他引:2  
The CD1 family is a large cluster of non-polymorphic, major histocompatibility complex (MHC) class-I-like molecules that bind distinct lipid-based antigens that are recognized by T cells. The most studied group of T cells that interact with lipid antigens are natural killer T (NKT) cells, which characteristically express a semi-invariant T-cell receptor (NKT TCR) that specifically recognizes the CD1 family member, CD1d. NKT-cell-mediated recognition of the CD1d-antigen complex has been implicated in microbial immunity, tumour immunity, autoimmunity and allergy. Here we describe the structure of a human NKT TCR in complex with CD1d bound to the potent NKT-cell agonist alpha-galactosylceramide, the archetypal CD1d-restricted glycolipid. In contrast to T-cell receptor-peptide-antigen-MHC complexes, the NKT TCR docked parallel to, and at the extreme end of the CD1d-binding cleft, which enables a lock-and-key type interaction with the lipid antigen. The structure provides a basis for the interaction between the highly conserved NKT TCR alpha-chain and the CD1d-antigen complex that is typified in innate immunity, and also indicates how variability of the NKT TCR beta-chain can impact on recognition of other CD1d-antigen complexes. These findings provide direct insight into how a T-cell receptor recognizes a lipid-antigen-presenting molecule of the immune system.  相似文献   
8.
Borg LE  Shearer CK  Asmerom Y  Papike JJ 《Nature》2004,432(7014):209-211
Primordial solidification of the Moon (or its uppermost layer) resulted in the formation of a variety of rock types that subsequently melted and mixed to produce the compositional diversity observed in the lunar sample suite. The initial rocks to crystallize from this Moon-wide molten layer (the magma ocean) contained olivine and pyroxene and were compositionally less evolved than the plagioclase-rich rocks that followed. The last stage of crystallization, representing the last few per cent of the magma ocean, produced materials that are strongly enriched in incompatible elements including potassium (K), the rare earth elements (REE) and phosphorus (P)--termed KREEP. The decay of radioactive elements in KREEP, such as uranium and thorium, is generally thought to provide the thermal energy necessary for more recent lunar magmatism. The ages of KREEP-rich samples are, however, confined to the earliest periods of lunar magmatism between 3.8 and 4.6 billion years (Gyr) ago, providing no physical evidence that KREEP is directly involved in more recent lunar magmatism. But here we present evidence that KREEP magmatism extended for an additional 1 Gyr, based on analyses of the youngest dated lunar sample.  相似文献   
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The “Instrumental Revolution” in chemistry refers to a transitional period in the mid-20th century during which sophisticated instrumentation based on physical principles was introduced to solve chemical problems. Historical and philosophical reflection on whether the revolution was a scientific one has been dominated by general models of scientific revolution, in particular, those proposed by Thomas Kuhn, I. B. Cohen and Ian Hacking. In this article I propose that the Industrial Revolution is a useful model for understanding the transformation wrought by the increasingly important role of machines in chemical research. Drawing on Marx's analysis of that event, I argue that that the Instrumental Revolution bears a striking resemblance to the industrial one. I offer grounds for thinking that the resemblance is not fortuitous, but rather reflects a general pattern of development involving the mechanization of the labor process. It is suggested that the cognitive consequences of radical changes in the means of production, as exemplified in the Instrumental Revolution, warrant the consideration of whether the latter is an instance of a kind of revolution in science rather than a singular episode.  相似文献   
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