The Molecular Dynamic Simulation of Zolpidem Interaction with Gamma Aminobutyric Acid Type A Receptor

Our goal was to generate the extracellular domain of gamma‐aminobutyric acid type A receptor (GABA_A receptor) by comparative modeling and to study the interaction of zolpidem with the GABA_A receptor. The modeling strategy was verified to provide reasonable 3‐dimensional coordinates. These coordinates helped to combine all the subunits well. The benzodiazepine (BZ) binding site was located in a binding pocket between the α₁ and γ₂ subunits of the GABA_A receptor. Zolpidem was selected to dock into the binding site. In our study, the residues of the binding pocket were suggested to be αHis129, αTyr187, αGly228, αThr234, αTyr237, γMet96, γPhe116, γSer130, γGly143, and γMet169. By the calculation of the docking module, the conformation of zolpidem docking in the BZ binding site was investigated. A hydrogen bond was found at γArg136 when zolpidem's conformation was in rank 2 of the docking score. The contracted binding pocket showed residues at αHis129, αTyr187, αGly228, αTyr237, γPhe116, and γMet169. Zolpidem docking in a contracted binding pocket might generate a hydrogen bond in α His 129.     

Optimal feedback control of the forced van der Pol system

A simple feedback control strategy for chaotic systems is investigated using the forced van der Pol system as an example. The strategy regards chaos control as an optimization problem, where the maximum magnitude Floquet multiplier of a target unstable periodic orbit (UPO) is used as a cost function that needs to be minimized. Thus, the method obtains the optimal control gain in terms of the stability of the target UPO. This strategy was recently proposed for the proportional feedback control (PFC) method. Here, it is extended to the highly popular delayed feedback control (DFC) method. Since the DFC method treats the system as a delay-differential equation whose phase space is infinite-dimensional, the characteristic multipliers are found through a truncation in the number of delayed states. Control of a target UPO is achieved for several values of the forcing amplitude. We compare the DFC and PFC methods in terms of stability of the controlled orbit, steady state error and control effort.     

Crystallographic report: Chlorobis(pyrrolinedithiocarbamato)antimony(III)

The X‐ray crystal structure of Sb(S₂CN(CH₂)₄)₂Cl features a five‐coordinate geometry for antimony within a ClS₄ donor set, provides evidence for a stereochemical influence exerted by the lone pair of electrons on antimony, and shows no evidence for molecular aggregation. Copyright © 2003 John Wiley & Sons, Ltd.     

Crystallographic report: Bis[bis(N,N‐diethyldithiocarbamato)zinc(II)] (trans‐1,2‐bis(4‐pyridyl)ethylene)trans‐1, 2‐bis(4‐pyridyl)ethylene lattice adduct

The dimeric and centrosymmetric structure of [Zn(S₂CNEt₂)₂(trans‐NC₅H₄C(H)?C(H)C₅H₄N)]₂ shows bidentate coordination by the dithiocarbamate ligands and a distorted square pyramidal geometry for zinc, defined by a NS₄ donor set with the N atom in the apical position. The compound co‐crystallises with a centrosymmetric molecule of trans‐NC₅H₄C(H)?C(H)C₅H₄N that does not form a significant interaction to the Zn atom. Copyright © 2003 John Wiley & Sons, Ltd.     

On-off collective imperfect phase synchronization and bursts in wave energy in a turbulent state

A new type of synchronization, on-off collective imperfect phase synchronization, is found in a turbulent state. In the driver frame the nonlinear wave system can be transformed to a set of coupled oscillators moving in a potential related to the unstable steady wave. In "on" stages the oscillators in different spatial scales adjust themselves to collective imperfect phase synchronization, inducing strong bursts in the wave energy. The interspike intervals display a power-law distribution. In addition to the embedded saddle point, it is emphasized that the delocalization of the master mode also plays an important role in developing the on-off synchronization.     

Analysis of chaotic saddles in high-dimensional dynamical systems: the Kuramoto-Sivashinsky equation

This paper presents a methodology to study the role played by nonattracting chaotic sets called chaotic saddles in chaotic transitions of high-dimensional dynamical systems. Our methodology is applied to the Kuramoto-Sivashinsky equation, a reaction-diffusion partial differential equation. The paper describes a novel technique that uses the stable manifold of a chaotic saddle to characterize the homoclinic tangency responsible for an interior crisis, a chaotic transition that results in the enlargement of a chaotic attractor. The numerical techniques explained here are important to improve the understanding of the connection between low-dimensional chaotic systems and spatiotemporal systems which exhibit temporal chaos and spatial coherence.     

On an improved adaptive reduced-order model for the computation of steady-state vibrations in large-scale non-conservative systems with friction joints

Nonlinear Dynamics - Joints are commonly used in many large-scale engineering systems to ease assembly, and ensure structural integrity and effective load transmission. Most joints are designed...     

Economic intermittency in a two-country model of business cycles coupled by investment

Intermittent behavior of economic dynamics is investigated by a two-country model of Keynes-Goodwin type business cycles. Numerical simulations show that after an economic system evolves from weak chaos to strong chaos the system keeps its memory before the transition and its time series alternates episodically between periods of weakly and strongly chaotic fluctuations. In addition, we examine the intermittent phenomena from the view point of business cycle patterns near the crisis point.     

一种新的烟草钙调素结合蛋白的分离鉴定

用^35S标记的钙调素(^35S-CaM)作探针，从烟草cDNA文库中筛选到一个cDNA克隆pTCB40．DNA测序表明，分离的cDNA片段具有的开放阅读框编码233个氨基酸的多肽链．所编码钙调素结合蛋白TCB40(CaM—binding protein，CaMBP)与离子通道蛋白的同源性高达81％．凝胶覆盖实验结果证明其表达的蛋白具有依赖Ca^2 的钙调素结合活性。缺失分析表明钙调素结合位点于其蛋白的C端。Northern blot分析发现，TCB40在烟草茎，叶和花中均表达，但在叶中的表达量明显高于其他器官。     

Crystallographic report: Bis(O‐methoxyethyldithiocarbonato)(4,7‐dimethyl‐1,10‐phenanthroline)cadmium(II)

The structure of mononuclear Cd(S₂COCH₂CH₂OCH₃)₂(4,7‐Me₂phen) shows an N₂S₄ donor set about cadmium that defines a coordination geometry intermediate between octahedral and trigonal prismatic. Copyright © 2003 John Wiley & Sons, Ltd.