首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   25篇
  免费   1篇
丛书文集   1篇
现状及发展   7篇
研究方法   3篇
综合类   15篇
  2020年   1篇
  2012年   4篇
  2011年   4篇
  2010年   2篇
  2009年   1篇
  2006年   1篇
  2005年   2篇
  2004年   2篇
  2000年   1篇
  1997年   1篇
  1994年   1篇
  1993年   2篇
  1990年   1篇
  1980年   1篇
  1978年   1篇
  1974年   1篇
排序方式: 共有26条查询结果,搜索用时 15 毫秒
1.
Interleukin (IL)-33 is a recently described pro-inflammatory cytokine. Here we demonstrate IL-33 as a regulator of functional osteoclasts (OCs) from human CD14+ monocytes. IL-33 stimulates formation of tartrate-resistant acid phosphatase (TRAP)+ multinuclear OCs from monocytes. This action was suppressed by anti-ST2 antibody, suggesting that IL-33 acts through its receptor ST2, but not by the receptor activator of NF-κB ligand (RANKL) decoy, osteoprotegerin, or anti-RANKL antibody. IL-33 stimulated activating phosphorylations of signaling molecules in monocytes that are critical for OC development. These included Syk, phospholipase Cγ2, Gab2, MAP kinases, TAK-1, and NF-κB. IL-33 also enhanced expression of OC differentiation factors including TNF-α receptor-associated factor 6 (TRAF6), nuclear factor of activated T cells cytoplasmic 1, c-Fos, c-Src, cathepsin K, and calcitonin receptor. IL-33 eventually induced bone resorption. This study suggests that the osteoclastogenic property of IL-33 is mediated through TRAF6 as well as the immunoreceptor tyrosine-based activation motif-dependent Syk/PLCγ pathway in human CD14+ monocytes.  相似文献   
2.
S Charpak  B H G?hwiler  K Q Do  T Kn?pfel 《Nature》1990,347(6295):765-767
Excitatory amino acids mediate fast synaptic transmission in the central nervous system through the activation of at least three distinct ionotropic receptors: N-methyl-D-aspartate (NMDA), the alpha-amino-3-hydroxy-5-methyl-isoxasole-4-propionate (AMPA)/quisqualate (QUIS) and the kainate subtypes (for reviews, see refs 1, 2). They also activate the additional QUIS 'metabotropic' receptor (sensitive to trans-1-amino-cyclopentyl-1,3-dicarboxylate, ACPD) linked to inositol phospholipid metabolism. We have used hippocampal slice cultures to study the electrophysiological consequences of the metabotropic response. We find that activation of an ACPD-sensitive QUIS receptor produces a 'slow' excitation of CA3 pyramidal cells, resulting from depression of a Ca2(+)-dependent K+ current and a voltage-gated K+ current. Combined voltage-clamp and microfluorometric recordings show that, although these receptors can trigger an increase in intracellular Ca2+ concentration, suppression of K+ currents is independent of changes in intracellular Ca2+. These effects closely resemble those induced by activating muscarinic acetylcholine receptors in the same neurons and suggest that excitatory amino acids not only act as fast ionotropic transmitters but also as slow neuromodulatory transmitters.  相似文献   
3.
4.
Summary Lipophilic, steric, electronic, and enzyme resistance characteristics of carboranylalanine, adamantylalanine, neopentylglycine and tert-butylglycine are described. The first 2 amino-acids display lipophilicities 2 orders of magnitude higher than tryptophan.This work was supported by research grants to Prof. R. Schwyzer from the Swiss National Science Foundation.  相似文献   
5.
6.
Tuning clathrate hydrates for hydrogen storage   总被引:1,自引:0,他引:1  
The storage of large quantities of hydrogen at safe pressures is a key factor in establishing a hydrogen-based economy. Previous strategies--where hydrogen has been bound chemically, adsorbed in materials with permanent void space or stored in hybrid materials that combine these elements--have problems arising from either technical considerations or materials cost. A recently reported clathrate hydrate of hydrogen exhibiting two different-sized cages does seem to meet the necessary storage requirements; however, the extreme pressures (approximately 2 kbar) required to produce the material make it impractical. The synthesis pressure can be decreased by filling the larger cavity with tetrahydrofuran (THF) to stabilize the material, but the potential storage capacity of the material is compromised with this approach. Here we report that hydrogen storage capacities in THF-containing binary-clathrate hydrates can be increased to approximately 4 wt% at modest pressures by tuning their composition to allow the hydrogen guests to enter both the larger and the smaller cages, while retaining low-pressure stability. The tuning mechanism is quite general and convenient, using water-soluble hydrate promoters and various small gaseous guests.  相似文献   
7.
针对部分断面掘进机液压系统可靠性低、故障较多等问题,根据可靠性基本理论,建立该液压系统的可靠性逻辑框图和可靠度计算模型,结合实例对某型掘进机的液压系统进行可靠度计算和可靠性分析,利用MATLAB进行仿真,获得了各液压子系统的可靠度仿真曲线,并给出提高系统可靠度的措施。  相似文献   
8.
基于灰色理论的含腐蚀缺陷油气管道剩余寿命预测分析   总被引:1,自引:0,他引:1  
含腐蚀缺陷油气管道剩余寿命预测是管道完整性及安全性评价的重要组成部分.以灰色理论的基本模型为基础,提出了管道剩余寿命预测的一种方法,包括预测腐蚀速率的基本步骤以及根据腐蚀速率预测剩余寿命的基本方法,为油气管道腐蚀检测周期的确定提供了一种依据.  相似文献   
9.
This paper presents an experimental research aiming to realize an artificial hind wing that can mimic the wing unfolding motion of AIIomyrina dichotoma, an insect in coleopteran order. Based on the understanding of working principles of beetle wing folding/unfolding mechanisms, the hind wing unfolding motion is mimicked by a combination of creative ideas and state-of-art artificial muscle actuator. In this work, we devise two types of artificial wings and the successfully demonstrate that they can be unfolded by actuation of shape memory alloy wires to provide actuation force at the wing base and along the leading edge vein. The folding/unfolding mechanisms may provide an insight for portable nano/micro air vehicles with morphing wings.  相似文献   
10.
The effectiveness of road traffic control systems can be increased with the help of a model that can accurately predict short-term traffic flow. Therefore, the performance of the preferred approach to develop a prediction model should be evaluated with data sets with different statistical characteristics. Thus a correlation can be established between the statistical properties of the data set and the model performance. The determination of this relationship will assist experts in choosing the appropriate approach to develop a high-performance short-term traffic flow forecasting model. The main purpose of this study is to reveal the relationship between the long short-term memory network (LSTM) approach's short-term traffic flow prediction performance and the statistical properties of the data set used to develop the LSTM model. In order to reveal these relationships, two different traffic prediction models with LSTM and nonlinear autoregressive (NAR) approaches were created using different data sets, and statistical analyses were performed. In addition, these analyses were repeated for nonstandardized traffic data indicating unusual fluctuations in traffic flow. As a result of the analyses, LSTM and NAR model performances were found to be highly correlated with the kurtosis and skewness changes of the data sets used to train and test these models. On the other hand, it was found that the difference of mean and skewness values of training and test sets had a significant effect on model performance in the prediction of nonstandard traffic flow samples.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号