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排序方式: 共有90条查询结果,搜索用时 171 毫秒
51.
E. M. Acton J. E. Christensen H. Stone L. Goodman 《Cellular and molecular life sciences : CMLS》1968,24(10):998-999
Résumé La saccharine a été fixée par son azote imidique sur le C6 du glucose, par l'action de la saccharine sodée sur un dérivé protégé dup-toluénesulfonyl-6-O-d-glucose, et élimination des groupes protecteurs pour former un composé hydrosoluble. La saveur amère peut être attribuée à l'élimination du proton imidique de la saccharine. 相似文献
52.
Safe handling of nanotechnology 总被引:7,自引:0,他引:7
Maynard AD Aitken RJ Butz T Colvin V Donaldson K Oberdörster G Philbert MA Ryan J Seaton A Stone V Tinkle SS Tran L Walker NJ Warheit DB 《Nature》2006,444(7117):267-269
53.
An index to assess the health and benefits of the global ocean 总被引:15,自引:0,他引:15
BS Halpern C Longo D Hardy KL McLeod JF Samhouri SK Katona K Kleisner SE Lester J O'Leary M Ranelletti AA Rosenberg C Scarborough ER Selig BD Best DR Brumbaugh FS Chapin LB Crowder KL Daly SC Doney C Elfes MJ Fogarty SD Gaines KI Jacobsen LB Karrer HM Leslie E Neeley D Pauly S Polasky B Ris K St Martin GS Stone UR Sumaila D Zeller 《Nature》2012,488(7413):615-620
The ocean plays a critical role in supporting human well-being, from providing food, livelihoods and recreational opportunities to regulating the global climate. Sustainable management aimed at maintaining the flow of a broad range of benefits from the ocean requires a comprehensive and quantitative method to measure and monitor the health of coupled human–ocean systems. We created an index comprising ten diverse public goals for a healthy coupled human–ocean system and calculated the index for every coastal country. Globally, the overall index score was 60 out of 100 (range 36–86), with developed countries generally performing better than developing countries, but with notable exceptions. Only 5% of countries scored higher than 70, whereas 32% scored lower than 50. The index provides a powerful tool to raise public awareness, direct resource management, improve policy and prioritize scientific research. 相似文献
54.
Mackay TF Richards S Stone EA Barbadilla A Ayroles JF Zhu D Casillas S Han Y Magwire MM Cridland JM Richardson MF Anholt RR Barrón M Bess C Blankenburg KP Carbone MA Castellano D Chaboub L Duncan L Harris Z Javaid M Jayaseelan JC Jhangiani SN Jordan KW Lara F Lawrence F Lee SL Librado P Linheiro RS Lyman RF Mackey AJ Munidasa M Muzny DM Nazareth L Newsham I Perales L Pu LL Qu C Ràmia M Reid JG Rollmann SM Rozas J Saada N Turlapati L Worley KC Wu YQ Yamamoto A Zhu Y Bergman CM Thornton KR 《Nature》2012,482(7384):173-178
A major challenge of biology is understanding the relationship between molecular genetic variation and variation in quantitative traits, including fitness. This relationship determines our ability to predict phenotypes from genotypes and to understand how evolutionary forces shape variation within and between species. Previous efforts to dissect the genotype-phenotype map were based on incomplete genotypic information. Here, we describe the Drosophila melanogaster Genetic Reference Panel (DGRP), a community resource for analysis of population genomics and quantitative traits. The DGRP consists of fully sequenced inbred lines derived from a natural population. Population genomic analyses reveal reduced polymorphism in centromeric autosomal regions and the X chromosome, evidence for positive and negative selection, and rapid evolution of the X chromosome. Many variants in novel genes, most at low frequency, are associated with quantitative traits and explain a large fraction of the phenotypic variance. The DGRP facilitates genotype-phenotype mapping using the power of Drosophila genetics. 相似文献
55.
P Dutta G Courties Y Wei F Leuschner R Gorbatov CS Robbins Y Iwamoto B Thompson AL Carlson T Heidt MD Majmudar F Lasitschka M Etzrodt P Waterman MT Waring AT Chicoine AM van der Laan HW Niessen JJ Piek BB Rubin J Butany JR Stone HA Katus SA Murphy DA Morrow MS Sabatine C Vinegoni MA Moskowitz MJ Pittet P Libby CP Lin FK Swirski R Weissleder M Nahrendorf 《Nature》2012,487(7407):325-329
During progression of atherosclerosis, myeloid cells destabilize lipid-rich plaques in the arterial wall and cause their rupture, thus triggering myocardial infarction and stroke. Survivors of acute coronary syndromes have a high risk of recurrent events for unknown reasons. Here we show that the systemic response to ischaemic injury aggravates chronic atherosclerosis. After myocardial infarction or stroke, Apoe-/- mice developed larger atherosclerotic lesions with a more advanced morphology. This disease acceleration persisted over many weeks and was associated with markedly increased monocyte recruitment. Seeking the source of surplus monocytes in plaques, we found that myocardial infarction liberated haematopoietic stem and progenitor cells from bone marrow niches via sympathetic nervous system signalling. The progenitors then seeded the spleen, yielding a sustained boost in monocyte production. These observations provide new mechanistic insight into atherogenesis and provide a novel therapeutic opportunity to mitigate disease progression. 相似文献
56.
Human contribution to the European heatwave of 2003 总被引:4,自引:0,他引:4
The summer of 2003 was probably the hottest in Europe since at latest ad 1500, and unusually large numbers of heat-related deaths were reported in France, Germany and Italy. It is an ill-posed question whether the 2003 heatwave was caused, in a simple deterministic sense, by a modification of the external influences on climate--for example, increasing concentrations of greenhouse gases in the atmosphere--because almost any such weather event might have occurred by chance in an unmodified climate. However, it is possible to estimate by how much human activities may have increased the risk of the occurrence of such a heatwave. Here we use this conceptual framework to estimate the contribution of human-induced increases in atmospheric concentrations of greenhouse gases and other pollutants to the risk of the occurrence of unusually high mean summer temperatures throughout a large region of continental Europe. Using a threshold for mean summer temperature that was exceeded in 2003, but in no other year since the start of the instrumental record in 1851, we estimate it is very likely (confidence level >90%) that human influence has at least doubled the risk of a heatwave exceeding this threshold magnitude. 相似文献
57.
58.
Identification of the gene (BBS1) most commonly involved in Bardet-Biedl syndrome,a complex human obesity syndrome 总被引:11,自引:0,他引:11
Mykytyn K Nishimura DY Searby CC Shastri M Yen HJ Beck JS Braun T Streb LM Cornier AS Cox GF Fulton AB Carmi R Lüleci G Chandrasekharappa SC Collins FS Jacobson SG Heckenlively JR Weleber RG Stone EM Sheffield VC 《Nature genetics》2002,31(4):435-438
Bardet-Biedl syndrome (BBS, OMIM 209900) is a genetic disorder with the primary features of obesity, pigmentary retinopathy, polydactyly, renal malformations, mental retardation and hypogenitalism. Individuals with BBS are also at increased risk for diabetes mellitus, hypertension and congenital heart disease. What was once thought to be a homogeneous autosomal recessive disorder is now known to map to at least six loci: 11q13 (BBS1), 16q21 (BBS2), 3p13 p12 (BBS3), 15q22.3 q23 (BBS4), 2q31 (BBS5) and 20p12 (BBS6). There has been considerable interest in identifying the genes that underlie BBS, because some components of the phenotype are common. Cases of BBS mapping ro BBS6 are caused by mutations in MKKS; mutations in this gene also cause McKusick-Kaufman syndrome (hydrometrocolpos, post-axial polydactyly and congenital heart defects). In addition, we recently used positional cloning to identify the genes underlying BBS2 (ref. 16) and BBS4 (ref. 17). The BBS6 protein has similarity to a Thermoplasma acidophilum chaperonin, whereas BBS2 and BBS4 have no significant similarity to chaperonins. It has recently been suggested that three mutated alleles (two at one locus, and a third at a second locus) may be required for manifestation of BBS (triallelic inheritance). Here we report the identification of the gene BBS1 and show that a missense mutation of this gene is a frequent cause of BBS. In addition, we provide data showing that this common mutation is not involved in triallelic inheritance. 相似文献
59.
T. W. Stone 《Cellular and molecular life sciences : CMLS》1973,29(6):666-667
Résumé Une électrode est décrite avec laquelle on peut stimuler une aire donnée du cerveau. On peut contrôler la direction du stimulus par cette électrode (Figure 2). Un diagramme de l'extremité de l'électrode est présenté à la Figure 1. 相似文献
60.