bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of methods for point‐charge representation of electrostatic fields
Authors: Dungsrikaew Virasak , Limtrakul Jumras , Hermansson Kersti , Probst Michael 
Published: October 2003

AbstractThe calculation of the electrostatic potential resulting from an infinite or extended array of charges in the interior of a region of interest is a frequent task in computational chemistry. In case of a periodic potential this can, for example, be done by Ewald summation or by multipole methods. An important alternative are those methods where arrays of auxiliary point charges are optimized with respect to charge and/or position to reproduce the original electrostatic potential. In the literature different variations are reported. We compare the performance of some of these with respect to their ability to reproduce the original potential and the computational effort required. Between (1) surface charges determined by the conductor‐boundary condition, (2) optimized surface charges, and (3) surface charges floating on the surface we find that (2) offers good quality with small computational costs involved. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Hybrid QM/MM studies on energetics of malonaldehyde in condensed phase
Authors: Shigeta Yasuteru 
Published: October 2003

AbstractEnergetics of eight enol isomers of a malonaldehyde (MA) at the ground state in CCl4 solvent environment have been investigated using a hybrid quantum mechanical (QM)/molecular mechanics (MM) method. It is found that relative energies of the isomers slightly change due to interactions between MA and surrounding atoms. In an isolated environment all eight isomers have stable planar structure. On the other hand, most of the isomers have nonplanar structure in CCl4 whose interactions with the solute molecules are, however, weak. Mainly, structural changes are found in the HOCC dihedral angle ϕHOCC, i.e., a hydrogen atom that is connected directly with an oxygen atom, is located at a nonplanar position, and other atoms remain almost planar. Vertical excitation energies of low‐lying excited states at the resultant optimized structure of each isomer are evaluated. The vertical excitation energies in CCl4 are almost the same as those in the isolated environment, but some changes were found in the triplet excitation states. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Development of a method for the direct analysis of peptide AM336 in monkey cerebrospinal fluid using liquid chromatography/electrospray ionization mass spectrometry with a mixed‐function column
Authors: Bu Wei , Freer Scott D. , Hollar Shelly M. , Stetson Philip L. , Boyd Robert A. , Kurek John B. , Sved Daniel W. 
Published: October 2003

AbstractA liquid chromatography/mass spectrometry (LC/MS) analytical procedure, using a single column for sample clean‐up, enrichment and separation, has been developed for the determination of the peptide AM336 in monkey cerebrospinal fluid (CSF). CSF samples were injected and analyzed using a polymer‐coated mixed‐function high‐performance liquid chromatography (HPLC) column with gradient elution and application of a timed valve‐switching event. The mass spectrometer was operated in the positive electrospray ionization (ESI+) mode with single ion recording (SIR) at m/z 920. The method was validated, yielding calibration curves with correlation coefficients greater than 0.9892. Assay precision and accuracy were evaluated by direct injection of AM336‐fortified CSF samples at three concentration levels. Analyzed concentrations ranged from 99.93 to 113.1% of their respective theoretical concentrations with coefficients of variation below 9.0%. An evaluation of the signal‐to‐noise (S/N) ratio for a 200 ng/mL calibration standard, considered to be the lower limit of quantitation (LLOQ), resulted in an estimated limit of detection (LOD) of 31.2 ng/mL. Preliminary data suggest the possibility of using this method to analyze AM336 also in plasma samples, pending the successful outcome of additional investigations. Copyright © 2003 John Wiley & Sons, Ltd.
Parallel determination of multiple protein metabolite interactions using cell extract, protein microarrays and mass spectrometric detection
Authors: Morozov Victor N. , Morozova Tamara Ya. , Johnson Kenneth L. , Naylor Stephen 
Published: October 2003

AbstractAnalysis of interactive networks between proteins and other molecular constituents is of paramount importance to delineate complex cellular processes. In order to facilitate this process, new technologies that allow rapid, high‐throughput parallel screening, as well as identification of constituents, are necessary. A particularly powerful combination in this regard could be the use of multiprotein microarrays coupled with mass spectrometry (MS). In the initial step of the method development we applied MS to single‐protein microarrays. We demonstrated that even a simplified version of the method allows rapid parallel label‐free assay of specific protein interactions with multiple metabolites derived from complex artificial and natural mixtures. The microarrays fabricated by the electrospray deposition technique and cross‐linked in glutaraldehyde vapor were brought into contact with droplets of solution containing either a natural extract of baker's yeast cells or an artificial cocktail of metabolites. After washing, the microarrays were placed into 75% methanol to denature proteins and release specifically bound metabolites. The eluates were then analyzed by electrospray ionization mass spectrometry (ESI‐MS) to simultaneously detect all the metabolites bound. Such a procedure applied to ten different proteins demonstrated that 50–400 ng of cross‐linked protein is enough to obtain ion intensities from metabolites that are well distinguishable above noise. The compatibility of microplates and different microarray designs with MS detection is discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Robust H∞ control for uncertain singular systems with state delay
Authors: Xu Shengyuan , Lam James , Yang Chengwu 
Published: October 2003

AbstractThis paper addresses the problem of robust H∞ control for uncertain continuous singular systems with state delay. The singular system under consideration involves state time delay and time‐invariant norm‐bounded uncertainty. Based on the linear matrix inequality (LMI) approach, we design a memoryless state feedback controller law, which guarantees that, for all admissible uncertainties, the resulting closed‐loop system is not only regular, impulse free and stable, but also meets an H∞‐norm bound constraint on disturbance attenuation. A numerical example is provided to demonstrate the applicability of the proposed method. Copyright © 2003 John Wiley & Sons, Ltd.
Robust Kalman filtering for uncertain discrete‐time linear systems
Authors: Garcia Germain , Tarbouriech Sophie , Peres Pedro L. D. 
Published: October 2003

AbstractThis paper presents a steady‐state robust state estimator for a class of uncertain discrete‐time linear systems with norm‐bounded uncertainty. It is shown that if the system satisfies some particular structural conditions and if the uncertainty has a specific structure, the gain of the robust estimator (which assures a guaranteed cost) can be calculated using a formula only involving the original system matrices. Among the conditions the system has to satisfy, the strongest one relies on a minimum phase argument. It is also shown that under the assumptions considered, the robust estimator is in fact the Kalman filter for the nominal system. Copyright © 2003 John Wiley & Sons, Ltd.
Characterizing the solution set of polynomial systems in terms of homogeneous forms: an LMI approach
Authors: Chesi G. , Garulli A. , Tesi A. , Vicino A. 
Published: October 2003

AbstractThis paper considers the problem of determining the solution set of polynomial systems, a well‐known problem in control system analysis and design. A novel approach is developed as a viable alternative to the commonly employed algebraic geometry and homotopy methods. The first result of the paper shows that the solution set of the polynomial system belongs to the kernel of a suitable symmetric matrix. Such a matrix is obtained via the solution of a linear matrix inequality (LMI) involving the maximization of the minimum eigenvalue of an affine family of symmetric matrices. The second result concerns the computation of the solution set from the kernel of the obtained matrix. For polynomial systems of degreeminnvariables, a basic procedure is available if the kernel dimension does not exceedm+1, while an extended procedure can be applied if the kernel dimension is less thann(m−1)+2. Finally, some application examples are illustrated to show the features of the approach and to make a brief comparison with polynomial resultant techniques. Copyright © 2003 John Wiley & Sons, Ltd.
Sustainability assessment in the German detergent industry: from stakeholder involvement to sustainability indicators
Authors: Seuring Stefan A. , Koplin Julia , Behrens Torsten , Schneidewind Uwe 
Published: October 2003

AbstractSince the early years of environmentalism, the detergent industry has been under pressure from NGOs and consumers. While the path towards an integrated product policy has been set, further developments towards sustainability are necessary.In a project conducted by the University of Oldenburg in cooperation with the German Detergent Manufacturers Association (IKW), future potentials for sustainable development were investigated. From this, a set of indicators was developed.This paper will review the project methodology, where a stakeholder assessment plays a key role, and present some findings. Stakeholder interviews and two workshops allowed discovery of the central issues to be tackled by the German detergent industry.The environmental product life‐cycle and stakeholder concept provide the theoretical basis for the so called sustainability matrices, one each for the environmental, economic and social dimensions. These matrices were used to facilitate discussions regarding relevant sustainability issues and indicators. Copyright © 2003 John Wiley & Sons, Ltd and ERP Environment.
Sustainable business versus sustainable environment: a case study of the Hong Kong shark fin business
Authors: Cheung Gordon C.K. , Chang Chak Yan 
Published: October 2003

AbstractThis study attempts to use the shark fin business in Hong Kong as a case to illustrate its challenge to international sustainability and global environmental governance. Regarding the commercial fishing of sharks and the degradation of the species, the paper begins with a survey of characteristics of sharks in the world and the responses from the international environmental agents. The authors will then detail their statistical findings, together with interviews with the shark fin manufacturers in Hong Kong. Their study began in 1999 and the statistical data ran from 1977 to 2001. Finally, the so‐called ‘foodway’ in the consumption of shark fin will be discussed with a view to the international concerns over endangered species in general and sharks in particular. Copyright © 2003 John Wiley & Sons, Ltd and ERP Environment.
Adaptive secure software architecture for electronic commerce
Authors: Tak Sung Woo , Park Eun Kyo 
Published: October 2003

AbstractAs Internet business exponentially grows, a need for the high security level categories that identify a group of connections or an individual transaction is manifest. Recently the development of efficient and secure software architecture has been in high demand. In this paper, we propose adaptive secure software architecture to support secure e‐commerce transactions. Our adaptive secure software architecture dynamically adapts security classes based on the nature and sensitivity of interactions among participants. Four security classes incorporate security levels of cryptographic techniques with a degree of information sensitivity. We have done extensive experiments on the performance of the proposed adaptive secure software architecture. Experimental results show that our adaptive secure software architecture provides e‐commerce transactions with high‐quality security services. Copyright © 2003 John Wiley & Sons, Ltd.
System and software designs for transaction processing in asymmetric communication environments
Authors: Huang Y. , Lee Y. H. 
Published: October 2003

AbstractObserving that it is impractical to use traditional methods to control concurrency in broadcast‐based asymmetric communication environments, we introduce a concurrency control protocol designed for broadcast‐based transaction processing called Server Timestamp and Update Broadcast Supported Concurrency (STUBcast). STUBcast supports two new correctness criteria proposed in this paper—Single Serializability and Local Serializability. These criteria are weaker than global serializability, but are practical and easier to achieve in broadcast environments. This article also discusses the software design for the simulation program and the protocol implementation. Simulation results collected using our simulation program suggest that STUBcast could be very efficient in realistic application environments. Copyright © 2003 John Wiley & Sons, Ltd.
Leveraging emerging network services to scale multimedia applications
Authors: Calvert K. , Griffioen J. , Mullins B. , Natarajan S. , Poutievski L. , Sehgal A. , Wen S. 
Published: October 2003

AbstractMulticast services have been used to transmit multimedia data to large receiver groups. Only recently have counterpart network services been introduced to provide similar scalability and anonymity in the opposite direction (i.e. messages from a group of senders destined for a common receiver).In this paper, we explore how these many‐to‐one services, specifically the concast service, can be used to improve the scalability and performance of multimedia applications. In particular, we show how such services can be used in both the control and data planes to overcome well‐known scalability problems (e.g. with Real Time Protocol) that are difficult to solve effectively with end‐system approaches alone. We validate our solutions by presenting experimental results taken from prototype video and audio applications we designed and implemented. Our initial results show substantial reductions in congestion‐induced loss using these generic services. Copyright © 2003 John Wiley & Sons, Ltd.
Directly linked porphyrin arrays
Authors: Aratani Naoki , Osuka Atsuhiro 
Published: October 2003

AbstractThe AgI‐promoted oxidative meso–meso coupling reaction of 5,15‐diaryl ZnII‐porphyrin was serendipitously found in the course of our synthetic approaches towards photosynthetic reaction centers. Based on this reaction, a variety of directly linked and fused porphyrin arrays have been synthesized, including linear meso–meso‐linked porphyrin arrays, windmill‐ and grid‐shaped porphyrin arrays, meso–β singly linked diporphyrins, β–β linked diporphyrins, meso–β doubly linked (fused) diporphyrins and oligoporphyrins, meso–meso β–β doubly linked (fused) diporphyrins, and meso–meso β–β–β–β triply linked (fused) diporphyrins. The meso–meso coupling reaction of 5,15‐diaryl ZnII‐porphyrins is advantageous considering its high regioselectivity as well as its ease of extension to large porphyrin arrays as is demonstrated by the synthesis of a discrete meso–meso‐linked 128‐mer and poly(5,15‐porphyrinylene). Finally, the oxidation of end‐phenyl capped meso–meso‐linked zinc porphyrins with DDQ‐Sc(OTf)3 gave π‐conjugated flat porphyrin tapes. To the best of our knowledge, the meso–meso linked 128‐mer is the longest man‐made discrete molecule, and the porphyrin tape 12‐mer is the most extensively conjugated porphyrin array, as evinced by the lowest electronic band peak at 3500 cm−1. © 2003 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 3: 225–234; 2003: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.10062
The repetitive C‐terminal domain of RNA polymerase II: Multiple conformational states drive the transcription cycle
Authors: Lin Patrick S. , Tremeau‐Bravard Alexandre , Dahmus Michael E. 
Published: October 2003

AbstractRNA polymerase (RNAP) II is a complex multisubunit enzyme responsible for the synthesis of mRNA in eukaryotic cells. The largest subunit contains at its C‐terminus a unique domain, designated the CTD, comprised of tandem repeats of the consensus sequence Tyr1Ser2Pro3Thr4Ser5Pro6Ser7. This repeat occurs 52 times in mammalian RNAP II. The CTD is subject to extensive phosphorylation at specific points in the transcription cycle by distinct CTD kinases that phosphorylate certain positions within the consensus repeat. The level and pattern of phosphorylation is determined by the concerted action of CTD kinases and CTD phosphatases. The highly dynamic modification by multiple CTD kinases and phosphatases generate distinct conformations of the CTD that facilitate the recruitment of specific macromolecular assemblies to RNAP II. These CTD interacting proteins influence formation of a preinitiation complex at the promoter and couple processing of the primary transcript to the elongation complex. © 2003 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 3: 235–245; 2003: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.10063
Determination of some rare earth elements by EDXRF and artificial neural networks
Authors: Schimidt Fernando , Cornejo‐Ponce Lorena , Bueno Maria Izabel M. S. , Poppi Ronei J. 
Published: October 2003

AbstractThis paper describes the simultaneous determination of Pr, Nd and Sm by EDXRF spectrometry using mixtures of oxides of these metals in a silica matrix. The data were treated by distinct neural network algorithms: back‐propagation (BP), Levenberg–Marquardt (LM) and two variations of back‐propagation (called BP‐SC, single component, and BP‐MC, multiple component), using results from the PLS model (partial least square regression) for comparison. The best applied model was the BP‐SC neural network, which produced relative standard errors of prediction of 17.5% for Pr, 12.5% for Nd and 12.6% for Sm. Copyright © 2003 John Wiley & Sons, Ltd.
Implementation of a spectrum fitting procedure using a robust peak model
Authors: Van Gysel M. , Lemberge P. , Van Espen P. 
Published: October 2003

AbstractThe need for an accurate description of characteristic x‐ray lines has led to the development of complex peak models that combine a Gauss, a shelf and a tail function. Via relationships that describe the shelf and tail parameters as a function of the energy, it is possible to reduce the number of fit parameters significantly. In this work, we carried out an experiment to study the shelf and tail parameters obtained with an HPGe detector. We observed a strong discontinuity in the shelf and tail parameters around the K‐edge energy of Ge. This indicates that these parameters are strongly dependent on the mass‐attenuation coefficient of the detector material. Therefore, we propose relationships that describe those parameters as a function of the energy and the mass‐attenuation coefficient. The implementation of these relationships in a fitting procedure results in a more robust fitting procedure with a much smaller number of fitting parameters. Excellent fits for HPGe spectra can be obtained. Because the detector dependence seems to be fairly general, we could successfully apply the model to Si(Li) spectra also. Copyright © 2003 John Wiley & Sons, Ltd.
Numerical description of photoelectric absorption coefficients for fundamental parameter programs
Authors: Ebel Horst , Svagera Robert , Ebel Maria F. , Shaltout Abdallah , Hubbell John H. 
Published: October 2003

AbstractAfter a systematic analysis of different databases and a comparison with empirical data, we decided to describe photoelectric absorption coefficients, coherent and incoherent scattering coefficients and mass attenuation coefficients in the energy range from 1 to 300 keV for elements from Z = 1 to 94 by a modified version of Scofield's tables in combination with scattering coefficients from Elam et al. Modifications include check and correction of edge positions, description of M4‐ and M5‐ranges of elements from promethium upwards by sawtooth responses and reduction of data by introduction of least‐squares fits of fifth order to Scofield's and Elam et al.'s numerical data. Our database was developed especially for application in fundamental parameter programs for quantitative x‐ray analysis (XRFA, EPMA, XPS and TEY). Copyright © 2003 John Wiley & Sons, Ltd.
Preparation of calibrating standards for x‐ray fluorescence spectrometry of trace metals in plastics
Authors: Nakano Kazuhiko , Nakamura Toshihiro 
Published: October 2003

AbstractConvenient x‐ray fluorescent spectrometry was developed for the determination of V, Cr, Co, Ni, Ge and Sb in plastic materials. The calibrating standards were prepared by casting of polyurethane or polyester including a xylene solution of organometallic compounds as a standard. The calibrating disk had a homogeneous elemental distribution and excellent durability. The calibration curves of six elements showed a good linearity of less than 50 mass ppm for V and Ni, 100 mass ppm for Co and Ge, 200 mass ppm for Cr, and 400 mass ppm for Sb. The lower limits of detection (3σ) of the present method were 0.19 mass ppm for V, 0.42 for Cr, 0.24 for Co, 0.18 for Ni, 0.066 for Ge, and 2.1 for Sb. The proposed method has been applied to several different industrial plastics. The quantitative results are in good agreement with those obtained by the AAS method and x‐ray fluorescent spectrometry using the fundamental parameter calculation method. Copyright © 2003 John Wiley & Sons, Ltd.
Role of antioxidant enzymatic defences against oxidative stress (H2O2) and the acquisition of oxidative tolerance in Candida albicans
Authors: González‐Párraga Pilar , Hernández José A. , Argüelles Juan Carlos 
Published: October 2003

AbstractIn Candida albicans, trehalose plays an essential role as a protector of cell integrity against oxidative challenge. A double homozygous mutant, tps1/tps1, deficient in trehalose synthesis, displayed severe cell mortality when exposed to high H2O2 concentrations, compared with its congenic parental (CAI‐4) strain (Alvarez‐Peral et al., 2002). We have examined the putative role of a set of well‐known antioxidant enzymes as components of the defence mechanism against oxidative challenges. When exposed to mild non‐lethal oxidative treatment (0.5 mM H2O2), a significant induction of catalase, glutathione reductase (GR), and Cu,Zn‐superoxide dismutase (SOD) was recorded in tps1/tps1 exponential cultures. However, in CAI‐4 cells, subjected to the same conditions, there was only a clear activation of catalase, Mn‐SOD and Cu,Zn‐SOD activities. The degree of activation was always much more pronounced in the trehalose‐deficient mutant than in its wild‐type counterpart, except for Mn‐SOD activity. After exposure to severe oxidative stress (50 mM H2O2) only GR and catalase activities increased in tps1/tps1 cultures, whereas in CAI‐4 cells GR but not catalase was induced. In both cell strains, 50 mM H2O2 caused inhibition of the Mn‐ and Cu,Zn‐SOD isozymes, this inhibition being more pronounced in tps1/tps1 cells. C. albicans is able to acquire adaptive oxidative tolerance by pretreatment with a low non‐stressing concentration of H2O2 before exposure to a drastic oxidative challenge. When these antioxidant activities were measured during the adaptive response, a greater degree of enzymatic antioxidant induction was consistently observed in the tps1/tps1 mutant with respect to the CAI‐4 strain. Together with a higher intrinsic sensitivity of tps1/tps1 cells, we suggest that this unexpected increase might be explained in terms of a compensatory mechanism to overcome the lack of endogenous trehalose upon drastic oxidative exposure, although this induction was not sufficient to improve the percentage of cell viability. Copyright © 2003 John Wiley & Sons, Ltd.