New Aspects of Cyclodextrin Chemistry Induced by Outside Type Complex Formation; Asymmetric Reduction of Indol-3-Pyruvic Acid with NaBH4 in Aqueous Solution

Asymmetric reduction of indol-3-pyruvic acid (IPA) with NaBH₄ in aqueous solution in the presence of various cyclodextrins (α-, β-, γ-, mono-6-amino-6-deoxy-β- and di-6^ABamino-6^AB-deoxy-β-cyclodextrin) was investigated. From the NMR and circular dichroism spectral studies, the conformation of the CyD–substrate complexes is suggested; the part of carboxylic group stay in the cavity of α-CyD, whole of IPA in β-CyD, two molecules in a γ-CyD cavity, and IPA(s) is/are on the rim of the cavity of mono-6-amino-6-deoxy-β- and di-6^ABamino-6^AB-deoxy-β-CyD (AβCyD, DAβCyD) with electrostatic interaction between amino group and carboxylic group. This conformational difference provides in the difference in the optical selectivity of reduction.     

Structure and function studies on enzymes with a catalytic carboxyl group(s): from ribonuclease T1 to carboxyl peptidases

A group of enzymes, mostly hydrolases or certain transferases, utilize one or a few side-chain carboxyl groups of Asp and/or Glu as part of the catalytic machinery at their active sites. This review follows mainly the trail of studies performed by the author and his colleagues on the structure and function of such enzymes, starting from ribonuclease T₁, then extending to three major types of carboxyl peptidases including aspartic peptidases, glutamic peptidases and serine-carboxyl peptidases.     

Translational medicine of the glutamate AMPA receptor

Psychiatric and neurological disorders severely hamper patient’s quality of life. Despite their high unmet needs, the development of diagnostics and therapeutics has only made slow progress. This is due to limited evidence on the biological basis of these disorders in humans. Synapses are essential structural units of neurotransmission, and neuropsychiatric disorders are considered as “synapse diseases”. Thus, a translational approach with synaptic physiology is crucial to tackle these disorders. Among a variety of synapses, excitatory glutamatergic synapses play central roles in neuronal functions. The glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) is a principal component of glutamatergic neurotransmission; therefore, it is considered to be a promising translational target. Here, we review the limitations of current diagnostics and therapeutics of neuropsychiatric disorders and advocate the urgent need for the promotion of translational medicine based on the synaptic physiology of AMPAR. Furthermore, we introduce our recent translational approach to these disorders by targeting at AMPARs.     

氢离子注入对硅单晶电子辐照缺陷和氢泡形成的影响

以50keV和100keV能量的氢离子注入p型(100)直拉硅单晶薄膜。注入剂量为10¹⁵—2×10¹⁷H⁺/cm²。试样在HU-1300型超高压透射电子显微镜中进行电子辐照和原位加热动态观察。结果表明在20—300℃温度范围内与未注氢硅相比,注氢硅在相同的电子辐照条件下产生的电子辐照缺陷较少,电子辐照缺陷形成所需的潜伏时间较长。在电子显微镜中加热试样时于190℃开始观察到氢泡,190—220℃范围内氢泡逐渐产生并长大 关键词：     

低能氘团簇离子(d+3)诱发固体靶内D-D核聚变过程中的团簇效应研究

通过对由三个氘原子组成的氘团簇离子(d⁺₃)与三个分立的氘核(3d⁺)在轰击吸氘固体靶时所发生的D-D聚变反应率的差别的研究，进而揭示氘团簇离子在与固体靶中的氘核发生聚变反应时所体现出的团簇效应.实验结果显示，在10—40keV/d能区，每个氘团簇中的氘核(d⁺₃/3)所产生的聚变反应率高于具有相同速度的独立氘核(d⁺)所产生的聚变反应率.反之，在50—100keV/d能区，独立氘核比之于氘团簇中的单个氘核所产生的聚变反应率要高.两者之间的比值具有非常明显的能量相关性.这种团簇特性与团簇离子本身特性及固体靶环境等多方面因素有关.对其作用过程和实验中观测到的现象的实质做了具体讨论. 关键词：     

Strength and precision of neurotransmission at mammalian presynaptic terminals

Classically, the basic concept of chemical synaptic transmission was established at the frog neuromuscular junction, and direct intracellular recordings from presynaptic terminals at the squid giant presynaptic terminal have further clarified principles of neurotransmitter release. More recently, whole-cell patch-camp recordings from the calyx of Held in rodent brainstem slices have extended the classical concept to mammalian synapses providing new insights into the mechanisms underlying strength and precision of neurotransmission and developmental changes therein. This review summarizes findings from our laboratory and others on these subjects, mainly at the calyx of Held, with a particular focus on precise, high-fidelity, fast neurotransmission. The mechanisms by which presynaptic terminals acquire strong, precise neurotransmission during postnatal development are also discussed.     

过渡金属促进的从三种不同的炔烃高效合成苯衍 生物的策略

报道利用过渡金属有机化合物(二茂锆和有机铜化合物),从三种不同的炔烃,如何实现了高选择性高产率并且一锅煮地合成苯衍生物。