Stripping Chronopotentiometry with Dry‐Preservable Supporting Electrolyte

The determination of some toxic metals by stripping chronopotentiometry with a supporting solution having an unconventional composition has been investigated with the aim of using such components in disposable measuring cells preservable in dry state and quite ready for use, only needing addition of a small volume of sample. The new supporting solution is prepared with a solid strong acid, p‐toluenesulfonic acid, in the place of the inorganic acids commonly used to improve the cation availability. The other components are, as usual, sodium chloride, which fixes the potential of the screen‐printed silver – silver chloride reference electrode, and mercury(II) chloride as the plating agent. This supporting solution has been tested in batch measurements with the mercury film glassy carbon electrode as well as with screen‐printed carbon‐ink electrodes, either with mercury film or bare. The physical shape of the mercury layer electrolytically deposited on screen‐printed carbon‐ink electrodes from a supporting solution containing 0.1 M p‐toluenesulfonic acid and 0.1 M sodium chloride has been investigated by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) microanalysis. In chronopotentiometric stripping p‐toluenesulfonic acid performs as well as the usual inorganic strong acids, particularly in terms of sensitivity. At 0.1 mol dm^?3 it proved very suitable for the determination of toxic metals, in particular lead(II), at levels down to a few μg dm^?3. The overall results appear promising and can open new avenues for preparing disposable cells for on‐field stripping chronopotentiometric determination of toxic metals.     

DNA interaction,cytotoxicity and molecular structure of cobalt complex of 4‐amino‐N‐(6‐chloropyridazin‐3‐yl)benzene sulfonamide in the presence of secondary ligand pyridine

Novel cobalt complex of 4‐amino‐N‐(6‐chloropyridazin‐3‐yl)benzene sulfonamide (sulfachloropyridazine) has been synthesized and characterized by elemental analysis, FT‐IR spectroscopy and magnetic susceptibility (VSM). Cobalt complex of Sulfachloropyridazine (Co‐SCP) crystallized in monoclinic space group P2₁/n with Z = 4. The structure is solved by direct method and refined to R = 0.099 for 4720 reflections with I ?4σ(I). The results of FT‐IR spectra suggest the binding of cobalt atom to the sulfonamide ligand which is in agreement with the crystal structure determination. In crystal structure, molecule is linked via, C‐H … π, C‐Cl … π and π … π intermolecular interactions. The computational studies like the optimization energy and root means square deviation compare with single crystal structure, frontier molecular orbital (Homo‐Lumo energy) and binding energy of the Co‐SCP has been carried out using DFT/B3LYP level of theory in gaseous phase. Hirshfeld surfaces and the 2D‐fingerprint analysis are performed to study the nature of interactions and their measurable contributions towards crystal packing. The interaction of the complex with DNA is investigated using viscosity measurement and absorption titration studies. The result shows the complex bind to DNA with intercalative mode with high DNA‐binding constant (K_b). Also, in vivo and in vitro cytotoxic studies are performed using S. pombe cells and brine shrimp lethality bioassay. DNA‐cleavage study shows better cleaving ability of the complex.     

An overview of analytical methodologies for the determination of antibiotics in environmental waters

The widespread occurrence of antibiotics as contaminants in the aquatic environment has increased attention in the last years. The concern over the release of antibiotics into the environment is related primarily to the potential for the development of antimicrobial resistance among microorganisms. This article presents an overview of analytical methodologies for the determination of quinolone (Qs) and fluoroquinolone (FQs), macrolide (MLs), tetracycline (TCs), sulfonamide (SAs) antibiotics and trimethoprim (TMP) in different environmental waters. The analysis of these antibiotics has usually been carried out by high-performance liquid chromatography (HPLC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) and to a lesser extent by ultraviolet (UV) or fluorescence detection (FD). A very important step before LC analysis is sample preparation and extraction leading to elimination of interferences and prevention of matrix effect and preconcentration of target analytes.     

基于增强终端的统一Centrex组网实现

本文分析了现有的统一Centrex组网架构及实现机制,提出了将一部分处理能力由网络推向终端、增强终端能力的业务实现方式,以减少对智能网的建设。文中描述了终端软件的开发,以及相关的组网架构和信令流程,讨论了业务数据同步的问题。     

移动智能网中SCP的设计研究

给出了GSM（全球移动通信系统）和智能网结合的总体结构，指出了移动智能网中SCP（业务控制点）设计要解决的问题：（1）怎样与HLR（归属位置寄存器）进行通信以得到移动网中与移动有关的数据，（2）怎样解决智能业务与移动网中已有业务的交互．本文对这两个问题给出了解决办法．最后，为了让业务提供者设计与移动有关的业务，定义了三个与移动有关的新SIB（业务无关构件）     

智能网SCP的两级并发模型与软件容错研究

智能网作为一种能够快速灵活地定义与提供电信新业务的体系结构，近年来受到人们的普遍重视，其中，业务控制点ＳＣＰ作为整个系统的核心，它的可靠性与全网的服务质量息息相关。本文中，我们首先指出了目前的ＳＣＰ产品在容错性能上存在的不足，然后根据ＳＣＰ的结构和运行机制提出一种两级并发模型，并基于此模型对其软件容错的途径进行了深入的探讨与研究。本文首次提出了应用软件出错情况下保证所有在线呼叫可靠处理的容错目标，并在ＳＣＰ系统级与呼叫级两个并发层次上给出了切实可行的容错策略或算法，最后，我们还对ＳＣＰ软件有效度的估算进行了进一步讨论。     

一种基于cdma2000的无线智能网构架研究

在分析了目前CDMA网络现状的基础上，提出了一种基于cdma2000移动网络的无线智能网构架WIN2000，针对其中需要新增的接口进行了分析，设计了合理的通信协议，对于智能数据业务的发展提出了相应的建议。     

Lignin biodegradation by the ascomyceteChrysonilia sitophila

The lignin biodegradation process has an important role in the carbon cycle of the biosphere. The study of this natural process has developed mainly with the use of basidiomycetes in laboratory investigations. This has been a logical approach since most of the microorganisms involved in lignocellulosic degradation belong to this class of fungi. However, other microorganisms such as ascomycetes and also some bacteria, are involved in the lignin decaying process. This work focuses on lignin biodegradation by a microorganism belonging to the ascomycete class,Chrysonilia sitophila. Lignin peroxidase production and characterization, mechanisms of lignin degradation (lignin model compounds and lignin in wood matrix) and biosynthesis of veratryl alcohol are outstanding. Applications of C.sitophila for effluent treatment, wood biodegradation and single-cell protein production are also discussed.     

“开机提醒”业务两种主要实现方式及比较

本文对开机提醒业务SCP及信令采集两种主要实现方式进行了深入介绍,并对其实现方式的优缺点进行了全面的比较。     

A Novel Sparse Penalty for Singular Value Decomposition

Singular value decomposition (SVD) is a tool widely used in data denoising, matrix approximation, recommendation system, text mining and computer vision. A m a jority of applications prefer sparse singular vectors to capture inherent structures and patterns of the input data so that the results are interpretable. We present a novel penalty for SVD to achieve sparsity. Comparing with the traditional penalties, the proposed penalty is scale, dimen-sional insensitive and bounded between 0 and 1, which are in favor of controlling sparsity. Regulated by the penalty, we provide an efficient algorithm to pro ject a vector onto a given sparse level in O(n) expected time. The efficient pro jection algorithm serve as a drudge for sparse SVD (SSVD). In experiments, SSVD is efficient and could cap-ture the latent structures and patterns of the input data.