Enhanced synaptic effectiveness following prolonged changes in synaptic use

Résumé Pour mieux étudier le rapport entre la diminution de l'utilisation chronique d'une synapse et son efficacité, l'amplitude de la réponse monosynaptique ascendante des fibres afférentes de Groupe I a été mesurée plusieurs semaines après ténotomie et déefférentation. La conclusion de cette étude est qu'une plus grande efficacité monosynaptique est associée à la diminution de l'utilisation des fibres afférentes du Groupe I.     

A microvolume molecular filter

Summary A microvolume polymer membrane filter based on Amicon hollow fibers is described which permits separation of low molecular weight compounds from proteins, and can be used for desalting volumes of 100 l or less, or to separate cellular protein debris from perfusates during release studies. The filter has the advantage of being reusable and having almost no void volume.     

隔震结构动力时程响应工程算法的精度对比

基于隔震系统对非比例阻尼动力响应的解偶效应,提出了可以计算任意多自由度体系时域动力响应的工程实用算法.引入一个实际隔震工程作为算例,在输入两种不同的地震波时,用本文算法计算地震响应,并与复振型分解法、双精度Fortran下的Wilson θ法及Matlab下的Simulink这三种方法的位移、速度和加速度时程曲线进行了对比,并分析了峰值响应误差.结果表明,本文算法与其它几种算法的时程曲线完全重合,当隔震阻尼比取值为设计阻尼水准时,具有良好的精度.     

Nova regulates brain-specific splicing to shape the synapse

Alternative RNA splicing greatly increases proteome diversity and may thereby contribute to tissue-specific functions. We carried out genome-wide quantitative analysis of alternative splicing using a custom Affymetrix microarray to assess the role of the neuronal splicing factor Nova in the brain. We used a stringent algorithm to identify 591 exons that were differentially spliced in the brain relative to immune tissues, and 6.6% of these showed major splicing defects in the neocortex of Nova2-/- mice. We tested 49 exons with the largest predicted Nova-dependent splicing changes and validated all 49 by RT-PCR. We analyzed the encoded proteins and found that all those with defined brain functions acted in the synapse (34 of 40, including neurotransmitter receptors, cation channels, adhesion and scaffold proteins) or in axon guidance (8 of 40). Moreover, of the 35 proteins with known interaction partners, 74% (26) interact with each other. Validating a large set of Nova RNA targets has led us to identify a multi-tiered network in which Nova regulates the exon content of RNAs encoding proteins that interact in the synapse.     

Spaced receiver observations of radio pulses

Preliminary observations have been carried out to look for radio signals associated with gravitational waves. Although inconclusive, the observations from five receivers in the British Isles suggest the value of pressing on with further experiments.