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71.
Tenesa A Farrington SM Prendergast JG Porteous ME Walker M Haq N Barnetson RA Theodoratou E Cetnarskyj R Cartwright N Semple C Clark AJ Reid FJ Smith LA Kavoussanakis K Koessler T Pharoah PD Buch S Schafmayer C Tepel J Schreiber S Völzke H Schmidt CO Hampe J Chang-Claude J Hoffmeister M Brenner H Wilkening S Canzian F Capella G Moreno V Deary IJ Starr JM Tomlinson IP Kemp Z Howarth K Carvajal-Carmona L Webb E Broderick P Vijayakrishnan J Houlston RS Rennert G Ballinger D Rozek L Gruber SB 《Nature genetics》2008,40(5):631-637
In a genome-wide association study to identify loci associated with colorectal cancer (CRC) risk, we genotyped 555,510 SNPs in 1,012 early-onset Scottish CRC cases and 1,012 controls (phase 1). In phase 2, we genotyped the 15,008 highest-ranked SNPs in 2,057 Scottish cases and 2,111 controls. We then genotyped the five highest-ranked SNPs from the joint phase 1 and 2 analysis in 14,500 cases and 13,294 controls from seven populations, and identified a previously unreported association, rs3802842 on 11q23 (OR = 1.1; P = 5.8 x 10(-10)), showing population differences in risk. We also replicated and fine-mapped associations at 8q24 (rs7014346; OR = 1.19; P = 8.6 x 10(-26)) and 18q21 (rs4939827; OR = 1.2; P = 7.8 x 10(-28)). Risk was greater for rectal than for colon cancer for rs3802842 (P < 0.008) and rs4939827 (P < 0.009). Carrying all six possible risk alleles yielded OR = 2.6 (95% CI = 1.75-3.89) for CRC. These findings extend our understanding of the role of common genetic variation in CRC etiology. 相似文献
72.
Micrometre-scale silicon electro-optic modulator 总被引:4,自引:0,他引:4
Metal interconnections are expected to become the limiting factor for the performance of electronic systems as transistors continue to shrink in size. Replacing them by optical interconnections, at different levels ranging from rack-to-rack down to chip-to-chip and intra-chip interconnections, could provide the low power dissipation, low latencies and high bandwidths that are needed. The implementation of optical interconnections relies on the development of micro-optical devices that are integrated with the microelectronics on chips. Recent demonstrations of silicon low-loss waveguides, light emitters, amplifiers and lasers approach this goal, but a small silicon electro-optic modulator with a size small enough for chip-scale integration has not yet been demonstrated. Here we experimentally demonstrate a high-speed electro-optical modulator in compact silicon structures. The modulator is based on a resonant light-confining structure that enhances the sensitivity of light to small changes in refractive index of the silicon and also enables high-speed operation. The modulator is 12 micrometres in diameter, three orders of magnitude smaller than previously demonstrated. Electro-optic modulators are one of the most critical components in optoelectronic integration, and decreasing their size may enable novel chip architectures. 相似文献
73.
Fox DB Frail DA Price PA Kulkarni SR Berger E Piran T Soderberg AM Cenko SB Cameron PB Gal-Yam A Kasliwal MM Moon DS Harrison FA Nakar E Schmidt BP Penprase B Chevalier RA Kumar P Roth K Watson D Lee BL Shectman S Phillips MM Roth M McCarthy PJ Rauch M Cowie L Peterson BA Rich J Kawai N Aoki K Kosugi G Totani T Park HS MacFadyen A Hurley KC 《Nature》2005,437(7060):845-850
The final chapter in the long-standing mystery of the gamma-ray bursts (GRBs) centres on the origin of the short-hard class of bursts, which are suspected on theoretical grounds to result from the coalescence of neutron-star or black-hole binary systems. Numerous searches for the afterglows of short-hard bursts have been made, galvanized by the revolution in our understanding of long-duration GRBs that followed the discovery in 1997 of their broadband (X-ray, optical and radio) afterglow emission. Here we present the discovery of the X-ray afterglow of a short-hard burst, GRB 050709, whose accurate position allows us to associate it unambiguously with a star-forming galaxy at redshift z = 0.160, and whose optical lightcurve definitively excludes a supernova association. Together with results from three other recent short-hard bursts, this suggests that short-hard bursts release much less energy than the long-duration GRBs. Models requiring young stellar populations, such as magnetars and collapsars, are ruled out, while coalescing degenerate binaries remain the most promising progenitor candidates. 相似文献
74.
Tachykinins in regulation of gastric motility and secretion 总被引:5,自引:0,他引:5
The tachykinins constitute a family of neuropeptides with a common C-terminal amino acid sequence. The best known tachykinin
is substance P. Tachykinins are found in the nerve plexuses and nerve fibers in the stomach of all species examined. The circular
muscle layer is densely innervated, whereas the longitudinal layer and the mucosa are less intensively innervated. Tachykinins
are also found in a significant number of afferent neurons with cell bodies in the dorsal root ganglia. Release of tachykinin
can be demonstrated in response to both electrical stimulation of the vagus nerves and application of capsaicin. In the stomach
all three known tachykinin receptors seem to be present. Although species variations exist, NK-2 receptors are generally present
on the musculature, NK-1 receptors on both neurons and muscles, and NK-3 receptors on neurons only. Tachykinins stimulate
motility in all parts of the stomach, but tachykinins also appear to inhibit motility in certain situations. Also, motility
initiated centrally, mediated through the vagus nerves, is influenced by tachykinins. The precise role of tachykinin in the
various motor programs in the stomach is not clear. Gastric acid secretion is influenced by tachykinins in several species.
Tachykinins do not seem to act as neurotransmitters directly on parietal cells, but may have a modulatory function. The importance
of tachykinins for the regulation of pepsinogen and hormone secretion from the stomach remains unclear.
Received 24 August 1999; received after revision 1 December 1999; accepted 3 December 1999 相似文献
75.
Dimeric tRNA precursors in yeast 总被引:23,自引:0,他引:23
76.
U. Schmidt U. C. Dubach I. Bieder B. Funk 《Cellular and molecular life sciences : CMLS》1972,28(4):385-386
Zusammenfassung Mit Hilfe einer Ultramikrotechnik konnte an isolierten gewundenen und geraden Hauptstücken der Rattenniere gezeigt werden, dass die alkalische Phosphatase nicht nur in der Bürstensaum-, sondern auch in der basalen Labyrinthmembran lokalisiert ist. Das Enzym ist infolgedessen kein geeignetes Leit-Enzym zur Erkennung des Bürstensaumes aus einem Plasmamembrangemisch. Es wird vorgeschlagen, das Fehlen der Na K ATPase-Aktivität als Mass für die Reinheit der Bürstensaumfraktion zu benutzen.
Herrn Prof. Dr. med. Dr. h. c. Otto Gsell zum 70. Geburtstag.
Grants of SNF Nr. 3.207.69 and DFG. 相似文献
Herrn Prof. Dr. med. Dr. h. c. Otto Gsell zum 70. Geburtstag.
Grants of SNF Nr. 3.207.69 and DFG. 相似文献
77.
Extracts of 14 species of phototrophic bacteria, partly grown with different sulfur compounds, were tested for their ability to form volatile sulfur compounds from adenylylsulfate (APS) and 3'-phosphoadenylylsulfate (PAPS). The Rhodospirillum species showed marked activities with both APS and PAPS while the Rhodopseudomonas species seem to prefer PAPS. The Chromatiaceae exhibited the strongest activities with APS, whereas Chlorobium limicola had equally high activity with PAPS. 相似文献
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