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101.
本文提出以狄拉克几何为基始的统一场论可演变为一独特的宇宙学; 其中, 广义相对论、量子电动力学和经典电动力学都为同一时空几何的不同表现。引力和以暗能为源的膨胀力也源于如是统一几何。 相似文献
102.
Kiemeney LA Thorlacius S Sulem P Geller F Aben KK Stacey SN Gudmundsson J Jakobsdottir M Bergthorsson JT Sigurdsson A Blondal T Witjes JA Vermeulen SH Hulsbergen-van de Kaa CA Swinkels DW Ploeg M Cornel EB Vergunst H Thorgeirsson TE Gudbjartsson D Gudjonsson SA Thorleifsson G Kristinsson KT Mouy M Snorradottir S Placidi D Campagna M Arici C Koppova K Gurzau E Rudnai P Kellen E Polidoro S Guarrera S Sacerdote C Sanchez M Saez B Valdivia G Ryk C de Verdier P Lindblom A Golka K Bishop DT 《Nature genetics》2008,40(11):1307-1312
We conducted a genome-wide SNP association study on 1,803 urinary bladder cancer (UBC) cases and 34,336 controls from Iceland and The Netherlands and follow up studies in seven additional case-control groups (2,165 cases and 3,800 controls). The strongest association was observed with allele T of rs9642880 on chromosome 8q24, 30 kb upstream of MYC (allele-specific odds ratio (OR) = 1.22; P = 9.34 x 10(-12)). Approximately 20% of individuals of European ancestry are homozygous for rs9642880[T], and their estimated risk of developing UBC is 1.49 times that of noncarriers. No association was observed between UBC and the four 8q24 variants previously associated with prostate, colorectal and breast cancers, nor did rs9642880 associate with any of these three cancers. A weaker signal, but nonetheless of genome-wide significance, was captured by rs710521[A] located near TP63 on chromosome 3q28 (allele-specific OR = 1.19; P = 1. 15 x 10(-7)). 相似文献
103.
D. Olijnyk A. M. Ibrahim R. K. Ferrier T. Tsuda M.-L. Chu B. A. Gusterson T. Stein J. S. Morris 《Cellular and molecular life sciences : CMLS》2014,71(19):3811-3828
Cell–matrix interactions control outgrowth of mammary epithelium during puberty and pregnancy. We demonstrate here that the glycoprotein fibulin-2 (FBLN2) is strongly associated with pubertal and early pregnant mouse mammary epithelial outgrowth. FBLN2 was specifically localized to the cap cells of the terminal end buds during puberty and to myoepithelial cells during very early pregnancy (days 2–3) even before morphological changes to the epithelium become microscopically visible, but was down-regulated thereafter. Exposure to exogenous oestrogen (E2) or E2 plus progesterone (P) increased Fbln2 mRNA expression in the pubertal gland, indicating hormonal control. FBLN2 was co-expressed and co-localised with the proteoglycan versican (VCAN) and co-localised with laminin (LN), while over-expression of FBLN2 in HC-11 cells increased cell adhesion to several extracellular matrix proteins including LN and fibronectin, but not collagens. Mammary glands from Fbln2 knockout mice showed no obvious phenotype but increased fibulin-1 (FBLN1) staining was detected, suggesting a compensatory mechanism by other fibulin family members. We hypothesise that similar to embryonic aortic smooth muscle development, FBLN2 and VCAN expression alters the cell–matrix interaction to allow mammary ductal outgrowth and development during puberty and to enable epithelial budding during pregnancy. 相似文献
104.
105.
Hansen SG Ford JC Lewis MS Ventura AB Hughes CM Coyne-Johnson L Whizin N Oswald K Shoemaker R Swanson T Legasse AW Chiuchiolo MJ Parks CL Axthelm MK Nelson JA Jarvis MA Piatak M Lifson JD Picker LJ 《Nature》2011,473(7348):523-527
The acquired immunodeficiency syndrome (AIDS)-causing lentiviruses human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) effectively evade host immunity and, once established, infections with these viruses are only rarely controlled by immunological mechanisms. However, the initial establishment of infection in the first few days after mucosal exposure, before viral dissemination and massive replication, may be more vulnerable to immune control. Here we report that SIV vaccines that include rhesus cytomegalovirus (RhCMV) vectors establish indefinitely persistent, high-frequency, SIV-specific effector memory T-cell (T(EM)) responses at potential sites of SIV replication in rhesus macaques and stringently control highly pathogenic SIV(MAC239) infection early after mucosal challenge. Thirteen of twenty-four rhesus macaques receiving either RhCMV vectors alone or RhCMV vectors followed by adenovirus 5 (Ad5) vectors (versus 0 of 9 DNA/Ad5-vaccinated rhesus macaques) manifested early complete control of SIV (undetectable plasma virus), and in twelve of these thirteen animals we observed long-term (≥1 year) protection. This was characterized by: occasional blips of plasma viraemia that ultimately waned; predominantly undetectable cell-associated viral load in blood and lymph node mononuclear cells; no depletion of effector-site CD4(+) memory T cells; no induction or boosting of SIV Env-specific antibodies; and induction and then loss of T-cell responses to an SIV protein (Vif) not included in the RhCMV vectors. Protection correlated with the magnitude of the peak SIV-specific CD8(+) T-cell responses in the vaccine phase, and occurred without anamnestic T-cell responses. Remarkably, long-term RhCMV vector-associated SIV control was insensitive to either CD8(+) or CD4(+) lymphocyte depletion and, at necropsy, cell-associated SIV was only occasionally measurable at the limit of detection with ultrasensitive assays, observations that indicate the possibility of eventual viral clearance. Thus, persistent vectors such as CMV and their associated T(EM) responses might significantly contribute to an efficacious HIV/AIDS vaccine. 相似文献
106.
Tam OH Aravin AA Stein P Girard A Murchison EP Cheloufi S Hodges E Anger M Sachidanandam R Schultz RM Hannon GJ 《Nature》2008,453(7194):534-538
107.
Alfred Nordmann 《Studies in history and philosophy of science》2012,43(1):38-46
Michael Friedman defines the scientific enterprise as an ongoing project with a dynamics of reason that persists through scientific revolutions: The coherence and continuity of science owes to a communicative rationality that is operative at all times. It assures us of our shared objective world by transforming subjective points of view into intersubjectively binding agreements. Though it takes a very broad approach epistemologically, this conception of science may yet be too narrow in respect to notions of objectivity. It excludes a prominent mode of knowledge production that might be called technoscientific. This exclusion becomes particularly evident in Friedman’s discussion of Heidegger as a critic of Cassirer and Carnap and as a critic of objectivity as “universal validity” of scientific propositions. If one tends to Heidegger’s own account of objectivity, one encounters a non-propositional notion of truth. Science is seen as a technology that brings forth phenomena and processes. Accordingly, even where modern physics appears to be concerned primarily with the formulation of theories and the testing of hypotheses, it uses mathematical and representational techniques to conceive and create the modern world. And more powerfully than intersubjective agreement, technologies assure us of the unity and objectivity of our simultaneously social as well as natural world. There may be good reasons to hold fast to the close affiliation of communicative rationality, science, and enlightenment. However, to the extent that it turns a blind eye to technoscientific knowledge production and the technological character of science, a philosophy of technoscience needs to develop an alternative perspective on questions of objectivity, explanation, inference, or validation. 相似文献
108.
Braig M Lee S Loddenkemper C Rudolph C Peters AH Schlegelberger B Stein H Dörken B Jenuwein T Schmitt CA 《Nature》2005,436(7051):660-665
Acute induction of oncogenic Ras provokes cellular senescence involving the retinoblastoma (Rb) pathway, but the tumour suppressive potential of senescence in vivo remains elusive. Recently, Rb-mediated silencing of growth-promoting genes by heterochromatin formation associated with methylation of histone H3 lysine 9 (H3K9me) was identified as a critical feature of cellular senescence, which may depend on the histone methyltransferase Suv39h1. Here we show that Emicro-N-Ras transgenic mice harbouring targeted heterozygous lesions at the Suv39h1, or the p53 locus for comparison, succumb to invasive T-cell lymphomas that lack expression of Suv39h1 or p53, respectively. By contrast, most N-Ras-transgenic wild-type ('control') animals develop a non-lymphoid neoplasia significantly later. Proliferation of primary lymphocytes is directly stalled by a Suv39h1-dependent, H3K9me-related senescent growth arrest in response to oncogenic Ras, thereby cancelling lymphomagenesis at an initial step. Suv39h1-deficient lymphoma cells grow rapidly but, unlike p53-deficient cells, remain highly susceptible to adriamycin-induced apoptosis. In contrast, only control, but not Suv39h1-deficient or p53-deficient, lymphomas senesce after drug therapy when apoptosis is blocked. These results identify H3K9me-mediated senescence as a novel Suv39h1-dependent tumour suppressor mechanism whose inactivation permits the formation of aggressive but apoptosis-competent lymphomas in response to oncogenic Ras. 相似文献
109.
Role of the cerebellum in the visual guidance of movement 总被引:4,自引:0,他引:4
Mathematicians, control engineers and information technologists are beginning to take a greater interest in neuroscience. They are perhaps starting to realize that they may be able to learn a few tricks from nature with which to improve their machines. At the same time there is a good chance that neuroscientists will benefit from their input of fresh ideas and techniques with which to attack the problems of understanding neural processing. One area of the brain which seems particularly promising in these respects is the cerebellum. 相似文献
110.