Induction of functional retinal projections to the somatosensory system

Optic axons can be induced to form permanent, retinotopic connections in the auditory (medial geniculate, MG) and somatosensory (ventrobasal, VB) nuclei of the Syrian hamster thalamus; this occurs when the principal targets of retinofugal axons are ablated in newborn hamsters and alternative terminal space is created by partial deafferentation of MG or VB. The experimentally induced retinal projection to the somatosensory nucleus occurs by the stabilization of an early, normally transient projection. The present study was undertaken to determine whether the anomalous, stabilized retino-VB projection is functional. Newborn hamsters were operated on to produce permanent retino-VB projections and when the animals were mature, neurophysiological recordings were made in the cortical targets of VB, the first and second somatosensory cortices (SI and SII, respectively). Visual stimulation within well-defined receptive fields reliably evoked multi-unit responses in SI and SII of operated, but not normal hamsters. The representations of the visual field in SI and SII showed a partially retinotopic organization. These results demonstrate that optic tract axons can form functional synapses in the thalamic somatosensory nucleus, and suggest that neural structures which normally process information specific to one sensory modality have the potential to mediate function for other modalities.     

Instructed learning in the auditory localization pathway of the barn owl

A bird sings and you turn to look at it a process so automatic it seems simple. But is it? Our ability to localize the source of a sound relies on complex neural computations that translate auditory localization cues into representations of space. In barn owls, the visual system is important in teaching the auditory system how to translate cues. This example of instructed plasticity is highly quantifiable and demonstrates mechanisms and principles of learning that may be used widely throughout the central nervous system.     

Functional identification of gene cluster for the aniline metabolic pathway mediated by transposable element

A convenient and widely applicable method has been developed to clone aniline metabolic gene cluster in this study. Three positive recombinant plasmids pDA1, pDB2 and pDB11 were cloned from genomic library of aniline degradation strain AD9. The result of aniline dioxygenase （AD） activity and catechol 2,3-oxygenase （C230） activity assay showed that pDA1 and pDB11 contain aniline dioxygenase genes and catechol 2,3-dioxygenase genes, respectively. The sequence analysis of the total 24.7-kb region revealed that this region contains 25 ORFs, of which 17 genes involve metabolism of aniline. In the gene cluster, the first five genes （tadQTA1A2B） and the subsequent gene （tadR1） were predicted to encode a multi-component aniline dioxygenase and a LysR-type regulator, respectively, while the others （tadD1C1D2C2EFGIJKL） were expected to encode metacleavage pathway enzymes for catechol degradation. The gene cluster was surrounded by two IS1071 sequences.     

中枢NMU抑制食欲作用受黑皮质激素受体途径部分介导

研究中枢神经介素U（NMU）受体2（NMU2R）与黑皮质激素（MC）受体途径（MCR3/4）在调节摄食行为和能量平衡方面的相互作用关系.对禁食或不禁食大鼠脑室注射NMU2R内源性配体NMU和MCR3/4信号途径高亲和力拮抗剂SHU9119,通过测定不同时间点大鼠摄食量和体重变化,探讨中枢NMU2R和黑皮质素受体途径在调节动物摄食行为上的作用及其相互关系.脑室注射NMU对大鼠食欲有显著抑制作用;在同时注射NMU和SHU9119的情况下,NMU2R对大鼠的这种食欲抑制作用会部分受到MCR3/4信号途径变化的影响;同样,对SHU9119前处理大鼠脑内注射NMU,NMU2R抑制食欲的作用也会明显降低,其在摄食方面的作用被部分抑制.结果提示,NMU能够有效的调节摄食行为,而且这种在摄食行为上的调控作用可能部分受MC受体途径介导.     

利用VB实现文档分析

详细讨论了VB语言环境下实现网络搜索引擎中文本分析的匹配操作遍历算法的技术原理和技术细节．并给出了实现这些算法的关键源程序．     

用Visual Basic设计屏幕保护程序

本文论述了屏幕保护程序的特点,讨论了如何用VisualBasic设计屏幕保护程序,通过典型的设计示例说明了屏幕保护程序的设计。     

在VB中实现远程数据库的访问

本文通过对数据库引擎的研究，在 VB中采用 DAO实现远程数据库的访问。     

用Visual FoxPro 5.0实现PowerPoint 2000中的动态效果

在Visual FoxPro5．0中充分利用Timer(计时器)控件，在Timer事件的过程中加入代码运行时让它按一定的时间间隔规则执行这些代码能够实现各种动态效果。     

用有向图法解决网页爬行中循环链接问题

提出网页构成的有向回路问题, 描述了由网页构成有向图的形式定义, 并给出了用有向图法发现网页构成的有向回路算法. 所给定的算法能使网页爬行器避免掉入由已爬行过的网页构成的有向回路陷阱.     

Rapid neutrophil adhesion to activated endothelium mediated by GMP-140.

Granule membrane protein-140 (GMP-140), a membrane glycoprotein of platelet and endothelial cell secretory granules, is rapidly redistributed to the plasma membrane during cellular activation and degranulation. Also known as PADGEM protein, GMP-140 is structurally related to two molecules involved in leukocyte adhesion to vascular endothelium: ELAM-1, a cytokine-inducible endothelial cell receptor for neutrophils, and the MEL-14 lymphocyte homing receptor. These three proteins define a new gene family, termed selectins, each of which contains an N-terminal lectin domain, followed by an epidermal growth factor-like module, a variable number of repeating units related to those in complement-binding proteins, a transmembrane domain, and a short cytoplasmic tail. Here we demonstrate that GMP-140 can mediate leukocyte adhesion, thus establishing a functional similarity with the other selectins. Human neutrophils and promyelocytic HL-60 cells bind specifically to COS cells transfected with GMP-140 complementary DNA and to microtitre wells coated with purified GMP-140. Cell binding does not require active neutrophil metabolism but is dependent on extracellular Ca2+. Within minutes after stimulation with phorbol esters or histamine, human endothelial cells become adhesive for neutrophils; this interaction is inhibited by antibodies to GMP-140. Thus, GMP-140 expressed by activated endothelium might promote rapid neutrophil targeting to sites of acute inflammation.     

如何提高Visual FoxPro的性能

正确地应用实用技巧和技术,可以大大改进Visual FoxPro的性能,提高数据的访问速度。     

如何提高Visual FoxPro的性能

正确地应用实用技巧和技术,可以大大改进Visual FoxPro的性能,提高数据的访问速度.