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排序方式: 共有106条查询结果,搜索用时 15 毫秒
1.
Architecture, engineering, and construction (AEC) global project teamwork is communication intensive and relies heavily on synchronous and asynchronous information and collaboration technologies (ICT). We explore in this paper how an asynchronous ICT, called ThinkTank, reshaped the work practice of design-construction global teams, and how the interaction with this ICT reshaped the purpose and benefits of its use. ThinkTank is a web-based asynchronous collaboration and discussion forum. We introduce the influence diffusion model (IDM) that formalizes the process of identifying the influence of people, messages, and terms mathematically. Discovering who the influence leaders in project teams are can be beneficial and critical from a corporate management perspective, since they can guide or motivate the team towards successful actions and outcomes. We present the ThinkTank-IDM integrated system and its validation with a testbed of 53 AEC global team project archived in ThinkTank over 8 years. 相似文献
2.
Summary Zn2+ (10–100 M) elevated the frequency of miniature end-plate potentials (MEPPs) in the mouse diaphragm. The effect did not depend on external Ca2+. Botulinum type A toxin (BTXA, 50 ng/ml) abolished MEPPs almost completely within 30 min. Zn2+ (100 M) restored MEPPs and increased their frequency after they had been abolished by BTXA in Ca2+-free solutions. The antagonistic effect of Zn2+ in the Ca2+-free solution was reduced by exposing the diaphragm to the toxin in the Ca2+-free solutions containing high K+. Thus, the action of BTXA is probably enhanced by depolarization of the motor nerve terminals. 相似文献
3.
4.
Sato T Mushiake S Kato Y Sato K Sato M Takeda N Ozono K Miki K Kubo Y Tsuji A Harada R Harada A 《Nature》2007,448(7151):366-369
A number of proteins are known to be involved in apical/basolateral transport of proteins in polarized epithelial cells. The small GTP-binding protein Rab8 was thought to regulate basolateral transport in polarized kidney epithelial cells through the AP1B-complex-mediated pathway. However, the role of Rab8 (Rab8A) in cell polarity in vivo remains unknown. Here we show that Rab8 is responsible for the localization of apical proteins in intestinal epithelial cells. We found that apical peptidases and transporters localized to lysosomes in the small intestine of Rab8-deficient mice. Their mislocalization and degradation in lysosomes led to a marked reduction in the absorption rate of nutrients in the small intestine, and ultimately to death. Ultrastructurally, a shortening of apical microvilli, an increased number of enlarged lysosomes, and microvillus inclusions in the enterocytes were also observed. One microvillus inclusion disease patient who shows an identical phenotype to Rab8-deficient mice expresses a reduced amount of RAB8 (RAB8A; NM_005370). Our results demonstrate that Rab8 is necessary for the proper localization of apical proteins and the absorption and digestion of various nutrients in the small intestine. 相似文献
5.
XinMiao Lü LiPing Zhu Mitsugu Nishimura Yoshimune Morita Takahiro Watanabe Toshio Nakamura Yong Wang 《科学通报(英文版)》2011,56(27):2931-2940
A 380-cm-long sediment core was acquired from the deep water area of Pumoyum Co, southern Tibet. Twenty-five plant residue
samples were selected, and organic carbon stable isotopes were obtained using the AMS 14C chronological method. The 14C age and carbon reservoir effect were calibrated with surface sedimentation rate measurements using 210Pb dating. Results showed that the core sediment deposited over 19 cal ka BP. Based on a multi-proxy analysis of TOC and IC
contents, grain size and pollen assemblage data, the palaeoclimatic evolution of Pumoyum Co was reconstructed since the last
glacial. Pumoyum Co was a shallow lake prior to 16.2 cal ka BP; although the glacier around the lake began to melt due to
increasing temperatures, climate was still cold and dry. In the interval of 16.2–11.8 cal ka BP, the sedimentary environment
fluctuated drastically and frequently. Two cold-events occurred at 14.2 and 11.8 cal ka BP, and these may correspond to the
Older Dryas and the Younger Dryas events, respectively. After 11.8 cal ka BP, Pumoyun Co developed into the deep lake as it
is now. The lake water temperature was relatively lower at that time because of influx of cold water from glacial meltwater
entering the lake. As a result, the multi-proxy indicators showed no sign of warm conditions. Comparisons between the sedimentary
record of Pumoyum Co with that of other lakes of the same age in southern Tibet indicate a warmer climate following the last
deglaciation influenced the southeastern Tibetan Plateau. These results imply that the southwest Asian monsoon gradually became
stronger since the deglaciation during its expansion to the inner plateau. The glacial-supplied water of the lake responded
sensitively to cold-events. The entire southern Tibet region was dominantly influenced climatically by the southwest Asian
monsoon during the Holocene. 相似文献
6.
Saitsu H Kato M Mizuguchi T Hamada K Osaka H Tohyama J Uruno K Kumada S Nishiyama K Nishimura A Okada I Yoshimura Y Hirai S Kumada T Hayasaka K Fukuda A Ogata K Matsumoto N 《Nature genetics》2008,40(6):782-788
Early infantile epileptic encephalopathy with suppression-burst (EIEE), also known as Ohtahara syndrome, is one of the most severe and earliest forms of epilepsy. Using array-based comparative genomic hybridization, we found a de novo 2.0-Mb microdeletion at 9q33.3-q34.11 in a girl with EIEE. Mutation analysis of candidate genes mapped to the deletion revealed that four unrelated individuals with EIEE had heterozygous missense mutations in the gene encoding syntaxin binding protein 1 (STXBP1). STXBP1 (also known as MUNC18-1) is an evolutionally conserved neuronal Sec1/Munc-18 (SM) protein that is essential in synaptic vesicle release in several species. Circular dichroism melting experiments revealed that a mutant form of the protein was significantly thermolabile compared to wild type. Furthermore, binding of the mutant protein to syntaxin was impaired. These findings suggest that haploinsufficiency of STXBP1 causes EIEE. 相似文献
7.
T. Horio Y. Kawabata T. Takayama S. Tahara J. Kawabata Y. Fukushi H. Nishimura J. Mizutani 《Cellular and molecular life sciences : CMLS》1992,48(4):410-414
A highly potent attractant of zoospores ofAphanomyces cochlioides, a causal fungus of the root rot disease of spinach (Spinacia oleracea), was isolated from spinach roots, and its structure was determined by spectroscopic evidence and chemical synthesis as cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone,1). A chromosorb particle prepared by soaking in solution of1 showed a potent attracting activity toward the zoospores using concentrations of1 above 10–9 or 10–10 M. 相似文献
8.
Glutamate receptors: RNA editing and death of motor neurons 总被引:1,自引:0,他引:1
The aetiology of sporadic amyotrophic lateral sclerosis (ALS), a fatal paralytic disease, is largely unknown. Here we show that there is a defect in the editing of the messenger RNA encoding the GluR2 subunit of glutamate AMPA receptors in the spinal motor neurons of individuals affected by ALS. This failure to swap an arginine for a glutamine residue at a crucial site in the subunit, which occurs normally in the affected brain areas of patients with other neurodegenerative diseases, will interfere with the correct functioning of the glutamate receptors and may be a contributory cause of neuronal death in ALS patients. 相似文献
9.
Nodal antagonists regulate formation of the anteroposterior axis of the mouse embryo 总被引:1,自引:0,他引:1
Yamamoto M Saijoh Y Perea-Gomez A Shawlot W Behringer RR Ang SL Hamada H Meno C 《Nature》2004,428(6981):387-392
Patterning of the mouse embryo along the anteroposterior axis during body plan development requires migration of the distal visceral endoderm (DVE) towards the future anterior side by a mechanism that has remained unknown. Here we show that Nodal signalling and the regionalization of its antagonists are required for normal migration of the DVE. Whereas Nodal signalling provides the driving force for DVE migration by stimulating the proliferation of visceral endoderm cells, the antagonists Lefty1 and Cerl determine the direction of migration by asymmetrically inhibiting Nodal activity on the future anterior side. 相似文献
10.
Metastasis suppressor gene KiSS-1 encodes peptide ligand of a G-protein-coupled receptor 总被引:72,自引:0,他引:72
Ohtaki T Shintani Y Honda S Matsumoto H Hori A Kanehashi K Terao Y Kumano S Takatsu Y Masuda Y Ishibashi Y Watanabe T Asada M Yamada T Suenaga M Kitada C Usuki S Kurokawa T Onda H Nishimura O Fujino M 《Nature》2001,411(6837):613-617
Metastasis is a major cause of death in cancer patients and involves a multistep process including detachment of cancer cells from a primary cancer, invasion of surrounding tissue, spread through circulation, re-invasion and proliferation in distant organs. KiSS-1 is a human metastasis suppressor gene, that suppresses metastases of human melanomas and breast carcinomas without affecting tumorigenicity. However, its gene product and functional mechanisms have not been elucidated. Here we show that KiSS-1 (refs 1, 4) encodes a carboxy-terminally amidated peptide with 54 amino-acid residues, which we have isolated from human placenta as the endogenous ligand of an orphan G-protein-coupled receptor (hOT7T175) and have named 'metastin'. Metastin inhibits chemotaxis and invasion of hOT7T175-transfected CHO cells in vitro and attenuates pulmonary metastasis of hOT7T175-transfected B16-BL6 melanomas in vivo. The results suggest possible mechanisms of action for KiSS-1 and a potential new therapeutic approach. 相似文献