A blue light-reversible reaction in an animal system (Daphnia pulex)

Summary A photoreversible reaction, previously found only in plants and fungi, has now been found in an animal system. Activation of development in diapausing embryos ofDaphnia pulex, induced with white light, was suppressed with subsequent exposure to narrow-band (470 nm) or wide-band (410–525 nm) blue light. Pulses of wide-band blue light repeatedly reversed white light activation.     

Intramuscular comparison of myosin isozymes and light chains in rat extensor digitorum longus muscle

Summary Complete muscle cross sections were obtained from the proximal and distal third regions of ten rat extensor digitorum longus muscles. Electrophoretic methods were then used to quantify the various myosin isozymes and light chains in each muscle specimen. The results demonstrated that the relative distribution of the various myosin isozyme and light chain variables do not vary significantly between the two sampling regions.     

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.     

生命起源前手性对映体富集与放大的数学规律与实验

生命起源前的原始海洋(池)中，由于没有手性源，手性化合物在合成过程中可能受到其他不对称因素(如手性对称性破缺)等影响，它们几乎都是以极小%ee值的非外消旋体(non-racemic enantiomers)存在。从数学理论出发，结合化学反应原理，推导出这些非外消旋体在通过某种反应后，其较小的%ee值(%ee₁)可以富集到较大的%ee值(%ee₂),尤其在很低%ee值的情况下，理论上其放大倍数(%ee₂/%ee₁)可以是指数级别的增加，而这是生命起源前得到高含量对映体(如L-氨基酸)所需要的。进一步使用约1%ee值的L-色氨酸甲酯(L-TME),通过与双功能基团物质(如乙二醛)发生反应，在0℃～室温条件下，将其放大富集到3.4%(%ee₂)。系列实验表明：最大放大倍数(%ee₂/%ee₁)可达1.9(从6.1%的%ee₁提高到11.7%的%ee₂);单次最大增量(Δ%ee=%ee_2<...