排序方式: 共有42条查询结果,搜索用时 301 毫秒
21.
Kinoshita M Matsui R Kato S Hasegawa T Kasahara H Isa K Watakabe A Yamamori T Nishimura Y Alstermark B Watanabe D Kobayashi K Isa T 《Nature》2012,487(7406):235-238
It is generally accepted that the direct connection from the motor cortex to spinal motor neurons is responsible for dexterous hand movements in primates. However, the role of the 'phylogenetically older' indirect pathways from the motor cortex to motor neurons, mediated by spinal interneurons, remains elusive. Here we used a novel double-infection technique to interrupt the transmission through the propriospinal neurons (PNs), which act as a relay of the indirect pathway in macaque monkeys (Macaca fuscata and Macaca mulatta). The PNs were double infected by injection of a highly efficient retrograde gene-transfer vector into their target area and subsequent injection of adeno-associated viral vector at the location of cell somata. This method enabled reversible expression of green fluorescent protein (GFP)-tagged tetanus neurotoxin, thereby permitting the selective and temporal blockade of the motor cortex–PN–motor neuron pathway. This treatment impaired reach and grasp movements, revealing a critical role for the PN-mediated pathway in the control of hand dexterity. Anti-GFP immunohistochemistry visualized the cell bodies and axonal trajectories of the blocked PNs, which confirmed their anatomical connection to motor neurons. This pathway-selective and reversible technique for blocking neural transmission does not depend on cell-specific promoters or transgenic techniques, and is a new and powerful tool for functional dissection in system-level neuroscience studies. 相似文献
22.
基于数据的建筑能耗分析与建模 总被引:1,自引:0,他引:1
对建筑能耗数据进行深入分析,提出了建立建筑电力能耗模型的方法.首先对建筑能耗进行了分项计量,统计了建筑逐时照明能耗数据,办公设备能耗数据以及办公人数,同时调查了建筑管理控制方式.经过分析可知,办公设备能耗数据与办公人数线性相关,而照明能耗数据与办公人数以及太阳辐射强度相关,但为非线性关系.根据不同类型数据的特点,分别建立了线性回归模型以及决策树模型.该模型可以预测建筑能耗并评估建筑管理方式对能耗的影响. 相似文献
23.
大桥由纪夫 《内蒙古师范大学学报(自然科学版)》2007,36(6):662-665
西方的地心体系(包括第谷的体系)基本上对太阳用了“简单偏心圆模型”.关于西方天文学的早期中国官方著作中。《新法算书》对太阳用了“简单偏心圆模型”,但是《历象考成》对太阳用了与“‘对点’模型”一样结果的“双‘本轮’模型”. 相似文献
24.
在PCR扩增水平上研究了La^ 3和Ce^ 3对Taq^TMDNA聚合酶的抑制机理,采用动态荧光比色法测定PCR扩增产物浓度,证明了La^ 3和Ce^ 3在10~50μmol/L抑制DNA复制是由于其抑制了Taq^TMDNA聚合酶的活性所致,且该抑制属竞争性的抑制,得到了La^ 3和Ce^ 3对Taq^TMDNA聚合酶的抑制常数分别为12.7μmol/L和14.4μmol/L。 相似文献
25.
焊接结构三维热变形的有限元模拟 总被引:13,自引:1,他引:13
采用三热弹塑性有限元法对焊接过程中的动态应力及焊后的残余应力和变形进行了数值模拟,探讨了焊接时力学行为的特点和提高解的精度和收敛性的途径,并介绍了若干成功的应用实例。 相似文献
26.
This paper describes the nearest neighbor (NN) search algorithm on the GBD(generalized BD) tree. The GBD tree is a spatial data structure suitable for two-or three-dimensional data and has good performance characteristics with respect to the dynamic data environment. On GIS and CAD systems, the R-tree and its successors have been used. In addition, the NN search algorithm is also proposed in an attempt to obtain good performance from the R-tree. On the other hand, the GBD tree is superior to the R-tree with respect to exact match retrieval, because the GBD tree has auxiliary data that uniquely determines the position of the object in the structure. The proposed NN search algorithm depends on the property of the GBD tree described above. The NN search algorithm on the GBD tree was studied and the performance thereof was evaluated through experiments. 相似文献
27.
: This paper describes the nearest neighbor (NN) search algorithm on the GBD(generalized BD) tree. The GBD tree is a spatial data structure suitable for two- or three-dimensional data and has good performance characteristics with respect to the dynamic data environment. On GIS and CAD systems, the R-tree and its-successors have been used. In addition, the NN search algorithm is also proposed in an attempt to obtain good performance from the R-tree. On the other hand, the GBD tree is superior to the R-tree with respect to exact match retrieval, because the GBD tree has auxiliary data that uniquely determines the position of the object in the structure. The proposed NN search algorithm depends on the property of the GBD tree described above. The NN search algorithm on the GBD tree was studied and the performance thereof was evaluated through experiments. 相似文献
28.
Summary The effects of high-K and high-Ca in the incubation medium on membrane-associated particles of the presynaptic membranes were examined. There was a marked increase in the density of protoplasmic fracture face after incubation in the high-K or high-Ca medium. 相似文献
29.
Enterprise systems must have the structure to adapt the change of business environment.When rebuilding enterprise system to meet the extended operational boundaries,the concept of IT city planning is applicable and effective.The aim of this paper is to describe the architectural approach from the integrated imformation infrastructure(In3) standpoint and to propose for applying the “City Planning” concept for rebuilding “inter-application spaghetti” enterprise systems.This is mainly because the portion of infrastructure has increased with the change of information systems from centralized systems to distributed and open systems.As enterprise systems have involved heterogeneity or architectural black box in them,it may be required the integration framework (meta-architecture)as a discipline based on heterogeneity that can provide comprehensive view of the enterprise systems.This paper proposes “EII Meta-model” as the integration framework that can optimize the overall enterprise systems from the IT city planning point of view.EII Meta-model consists of “Integrated Information Infrastructure Map(In3-Map)”,“Service·Framework” and “IT Scenario”.It would be applicable and effective for the viable enterprise,because it has the mechanism to adapt the change.Finally,we illustrate a case of information system in an online securities company and demonstrate spplicability and effectiveness of EII Meta-model to meet their business goals. 相似文献
30.
Yasuda K Miyake K Horikawa Y Hara K Osawa H Furuta H Hirota Y Mori H Jonsson A Sato Y Yamagata K Hinokio Y Wang HY Tanahashi T Nakamura N Oka Y Iwasaki N Iwamoto Y Yamada Y Seino Y Maegawa H Kashiwagi A Takeda J Maeda E Shin HD Cho YM Park KS Lee HK Ng MC Ma RC So WY Chan JC Lyssenko V Tuomi T Nilsson P Groop L Kamatani N Sekine A Nakamura Y Yamamoto K Yoshida T Tokunaga K Itakura M Makino H Nanjo K Kadowaki T Kasuga M 《Nature genetics》2008,40(9):1092-1097
We carried out a multistage genome-wide association study of type 2 diabetes mellitus in Japanese individuals, with a total of 1,612 cases and 1,424 controls and 100,000 SNPs. The most significant association was obtained with SNPs in KCNQ1, and dense mapping within the gene revealed that rs2237892 in intron 15 showed the lowest Pvalue (6.7 x 10(-13), odds ratio (OR) = 1.49). The association of KCNQ1 with type 2 diabetes was replicated in populations of Korean, Chinese and European ancestry as well as in two independent Japanese populations, and meta-analysis with a total of 19,930 individuals (9,569 cases and 10,361 controls) yielded a P value of 1.7 x 10(-42) (OR = 1.40; 95% CI = 1.34-1.47) for rs2237892. Among control subjects, the risk allele of this polymorphism was associated with impairment of insulin secretion according to the homeostasis model assessment of beta-cell function or the corrected insulin response. Our data thus implicate KCNQ1 as a diabetes susceptibility gene in groups of different ancestries. 相似文献