Influencing Factors on the Physicochemical Characteristics of Tea Polysaccharides

Tea polysaccharides (TPSs) are one of the main bioactive constituents of tea with various biological activities such as hypoglycemic effect, antioxidant, antitumor, and immunomodulatory. The bioactivities of TPSs are directly associated with their structures such as chemical composition, molecular weight, glycosidic linkages, and conformation among others. To study the relationship between the structures of TPSs and their bioactivities, it is essential to elucidate the structure of TPSs, particularly the fine structures. Due to the vast variation nature of monosaccharide units and their connections, the structure of TPSs is extremely complex, which is also affected by several major factors including tea species, processing technologies of tea and isolation methods of TPSs. As a result of the complexity, there are few studies on their fine structures and chain conformation. In the present review, we aim to provide a detailed summary of the multiple factors influencing the characteristics of TPS chemical structures such as variations of tea species, degree of fermentation, and preparation methods among others as well as their applications. The main aspects of understanding the structural difference of TPSs and influencing factors are to assist the study of the structure and bioactivity relationship and ultimately, to control the production of the targeted TPSs with the most desired biological activity.     

新型书写方式—化学书写术

应用化学原理发明了化学书写术，它比现行的书写方式具有突出的优点。     

Electrophoretic deposition of bacterial cells

The possibility to use alternating current electrophoretic deposition (AC-EPD) to deposit living cells in the form of Staphylococcus aureus and Escherichia coli on stainless steel was assessed. The experimental results revealed that these bacteria can be successfully deposited on metallic surfaces from demineralized water and sucrose based solutions using asymmetric unbalanced electric fields. Cell viability of the deposited bacteria was influenced by the strain and deposition medium.     

Magnesium ion conducting, room temperature molten electrolytes

Room temperature, magnesium ion conducting binary molten electrolyte consisting of acetamide and magnesium perchlorate has been prepared and characterized. The molten liquid is very stable and shows high ionic conductivity, of the order of several mS cm⁻¹ at 25 °C with other favourable physicochemical properties. Vibrational spectroscopic studies reveal that the free ion concentration is higher than that of ion pairs and aggregates in the melt. The electrochemical reversibility of magnesium deposition and dissolution is demonstrated using voltammetry and impedance studies. Preliminary studies on rechargeable batteries assembled using γ-MnO₂ and Mg metal as the electrodes together with the molten electrolyte show high discharge capacity.     

COD速测仪测定工业废水中CODCr

采用标准回流法和仪器法（用ＣＯＤ速测仪）对工业废水化学需氧量进行对照测定，结果发现，用ＣＯＤ速测仪测定工业废水，简便、快速、精密度好、准确度高。     

The Kinetic Theory of Simple Reacting Spheres: I. Global Existence Result in a Dilute-Gas Case

Existence of global-in-time, spatially inhomogeneous, and L ¹-renormalized solutions is proven for the model of simple reacting spheres under the assumptions that initially the system has a finite total mass, energy, and entropy.     

测量和减小纳米凹凸面摩擦力的分子新技术

报道了美国用原子力显微镜可直接检测超微型设备内发动机转子与外表表面上凸点之间摩擦力的大小的研究成果，介绍了降低了时机的摩擦力的方法。     

Coordination Chemistry of Lipoic Acid and Related Compounds V [1]. New Heteroditopic Ligands Derived from Monoazacrown Ethers and Lipoic Acid

Summary.  Lipoyl imidazolide reacts with aza-15-crown-5 (1,4,7,10-tetraoxa-13-azacyclopentadecane) or aza-18-crown-6 (1,4,7,10,13-pentaoxa-16-azacyclooctadecane) to afford new N-lipoylated azacrown compounds in good yields. These compounds can be transformed into 1,3-dithiols and amines by reduction with complex hydrides of the disulfide and/or amide group of the lipoyl chain. The new pendant-arm macrocycles react as heteroditopic ligands by forming dithiolate and disulfide complexes with the ‘soft’ metal ions Ni²⁺ and Pd²⁺, respectively, and an amine complex with the ‘hard’ Li⁺ ion. Semiempirical and DFT calculations on the complexation of a lithium ion give a most favourable structure in which the azacrown and two solvent molecules are in contact with the metal but not the pendant arm. Received January 29, 2002; accepted (revised) March 25, 2002     

Stationary diffusion in the membrane systems with the ongoing reversible chemical reactions

The diffusion phenomena were analyzed using the phenomenological equations of the thermodynamics of irreversible processes. The diffusion coefficient was thought to be dependent on local concentrations and pressure, unlike it was done in the linear theories. The reversible chemical reactions were modeled as intermolecular interaction. The ideal and regular solutions and solutions, described by the Margules's and Sketchard–Hammer's equations, were investigated and analytical solutions were found.     

Sparse grids and hybrid methods for the chemical master equation

The direct numerical solution of the chemical master equation (CME) is usually impossible due to the high dimension of the computational domain. The standard method for solution of the equation is to generate realizations of the chemical system by the stochastic simulation algorithm (SSA) by Gillespie and then taking averages over the trajectories. Two alternatives are described here using sparse grids and a hybrid method. Sparse grids, implemented as a combination of aggregated grids are used to address the curse of dimensionality of the CME. The aggregated components are selected using an adaptive procedure. In the hybrid method, some of the chemical species are represented macroscopically while the remaining species are simulated with SSA. The convergence of variants of the method is investigated for a growing number of trajectories. Two signaling cascades in molecular biology are simulated with the methods and compared to SSA results. AMS subject classification (2000)  65C20, 60J25, 92C45