bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copper Corrosion: Comparison between Naturally Aged Papers and Artificially Aged Model Papers
Authors: Henniges Ute , Bürger Ulrike , Banik Gerhard , Rosenau Thomas , Potthast Antje 
Published: January 2007

AbstractSummary: Copper corrosion on paper works of art is commonly explained by copper ion‐catalysed cellulose oxidation, usually reflected by discoloration of pigment and surrounding paper as well as by loss of mechanical strength. In this study, model paper and historic paper samples, both containing copper pigments, were compared using fluorescence labelling of carbonyl groups and subsequent GPC analysis. The historic paper samples did not show any typical sign of copper pigment induced discoloration, but high brittleness. In artificially copper‐corroded paper samples the distribution of carbonyl groups in combination with the molecular weight distribution of cellulose clearly indicated the occurrence of oxidative processes. In contrast, only insignificant oxidative damage was detected in the case of the paper fragments from an original work of art, a codex from the 15th century. Here, mostly degradation by hydrolytic action was revealed. There was no introduction of carbonyl groups into the bulk section of the molecular weight distribution, and the gain in new carbonyl groups corresponded to the number of reducing end groups newly generated by hydrolysis.
Phase Behavior of Amphiphilic Molecules in the Presence of One Solvent: A Dissipative Particle Dynamics Study
Authors: Huang Ching‐I , Hsueh Hsiao‐Yang , Lan Yi‐Kang , Lin Yu‐Chih 
Published: January 2007

AbstractWe simulate the phase behavior of amphiphilic molecules in the presence of one solvent by DPD. In general, DPD has successfully captured most of the effects of composition of amphiphilic molecules, solvent selectivity, and solvent amount, on the phase transition behavior obtained by both SCMF calculations and experiments. When a neutral good solvent is added, the solutions undergo a lyotropic transition analogous to the thermotropic transition in the melts. Furthermore, the order‐disorder transition results obtained via DPD are in good agreement with theoretical predictions by including the fluctuation effects, as well as with experiments. In the selective solvents, various transitions from the “normal” phases (i.e., the minority blocks form the minor domains) to even the “inverted” phases (formed by the majority blocks) have been observed by varying solvent selectivity and solvent amount. Since the packing order of the spheres is greatly affected by the finite size of the simulation box, it becomes difficult to examine the most stable packing array of spheres via DPD as has been predicted by SCMF theory. However, DPD reveals a possible spherical order of A15, which has been ignored in current SCMF work but observed in some amphiphilic molecule systems.magnified image
Models and methods of decision making in fuzzy environment and their applications to power engineering problems
Authors: Canha L. , Ekel P. , Queiroz J. , Schuffner Neto F. 
Published: January 2007

AbstractResults of research into the use of fuzzy sets for handling various forms of uncertainty in optimization problems are presented. Two types of situations which need the application of a multicriteria approach are classified. According to this, two classes of models (〈X, M〉 and 〈X, R〉 models) are considered with utilizing the Bellman–Zadeh approach to decision making in a fuzzy environment and techniques for modelling of fuzzy preference relations for their analysis. The application of the Bellman–Zadeh approach for solving 〈X, M〉 problems conforms to the principle of guaranteed result and provides constructive lines in obtaining harmonious solutions on the basis of analysing associated maxmin problems. Analysis of 〈X, R〉 models is considered as part of a general approach to solving problems with fuzzy coefficients. Three techniques for processing of fuzzy preferences relations are considered. The first technique is associated with building and analysing a membership function of a subset of non‐dominated alternatives considering all criteria simultaneously. The second technique is of a lexicographic character and consists in step‐by‐step consideration of criteria. The third technique is based on aggregating membership functions of subsets of non‐dominated alternatives for each criterion. The results of the paper are universally applicable and are already being used to solve power engineering problems. It is illustrated by considering problems of multicriteria power and energy shortage allocation, multicriteria power system operation, and substation planning with considering criteria of quantitative as well as of qualitative character. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of block matrix preconditioners for elliptic optimal control problems
Authors: Mathew T. P. , Sarkis M. , Schaerer C. E. 
Published: January 2007

AbstractIn this paper, we describe and analyse several block matrix iterative algorithms for solving a saddle point linear system arising from the discretization of a linear‐quadratic elliptic control problem with Neumann boundary conditions. To ensure that the problem is well posed, a regularization term with a parameter α is included. The first algorithm reduces the saddle point system to a symmetric positive definite Schur complement system for the control variable and employs conjugate gradient (CG) acceleration, however, double iteration is required (except in special cases). A preconditioner yielding a rate of convergence independent of the mesh size h is described for Ω ⊂ R2 or R3, and a preconditioner independent of h and α when Ω ⊂ R2. Next, two algorithms avoiding double iteration are described using an augmented Lagrangian formulation. One of these algorithms solves the augmented saddle point system employing MINRES acceleration, while the other solves a symmetric positive definite reformulation of the augmented saddle point system employing CG acceleration. For both algorithms, a symmetric positive definite preconditioner is described yielding a rate of convergence independent of h. In addition to the above algorithms, two heuristic algorithms are described, one a projected CG algorithm, and the other an indefinite block matrix preconditioner employing GMRES acceleration. Rigorous convergence results, however, are not known for the heuristic algorithms. Copyright © 2007 John Wiley & Sons, Ltd.
Decreased EXT expression and intracellular accumulation of heparan sulphate proteoglycan in osteochondromas and peripheral chondrosarcomas
Authors: Hameetman L , David G , Yavas A , White SJ , Taminiau AHM , Cleton‐Jansen A‐M , Hogendoorn PCW , Bovée JVMG 
Published: January 2007

AbstractMutational inactivation of EXT1 or EXT2 is the cause of hereditary multiple osteochondromas. These genes function in heparan sulphate proteoglycan (HSPG) biosynthesis in the Golgi apparatus. Loss of heterozygosity of the EXT1 locus at 8q24 is frequently found in solitary osteochondromas, whereas somatic mutations are rarely found. We investigated the expression of EXT1 and EXT2 (quantitative RT‐PCR) and of different HSPGs (immunohistochemistry) in solitary and hereditary osteochondromas and in cases with malignant progression to secondary peripheral chondrosarcoma, in relation to possible mutations and promoter methylation. The mutation status of patients with multiple osteochondromas correlated with decreased EXT1 or EXT2 expression found in their resected tumours. We could not show somatic point mutations or promoter hypermethylation in 17 solitary tumours; however, EXT1 expression was decreased in 15 cases, whereas EXT2 was not. Intracellular accumulation of syndecan‐2 and heparan sulphate‐bearing isoforms of CD44 (CD44v3) was found in most tumours, which concentrated in the Golgi apparatus as shown by confocal microscopy. This contrasted with the extracellular expression found in normal growth plates. In conclusion, mutational inactivation of either EXT1 or EXT2 leads to loss of mRNA expression of the corresponding gene. We hypothesize that loss of EXT expression disrupts the function of the EXT1/2 complex in HSPG biosynthesis, resulting in the intracellular accumulation of HSPG core proteins that we found in these tumours. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Changes in cancer worry associated with participation in ovarian cancer screening
Authors: Andersen M. Robyn , Drescher Charles W. , Zheng Yingye , Bowen Deborah J. , Wilson Susan , Young Alicia , McIntosh Martin , Mahony Barry S. , Lowe Kimberly A. , Urban Nicole 
Published: January 2007

AbstractWhile ovarian cancer is rare and screening is not recommended for most women, it is being studied as a way to reduce ovarian cancer mortality. As effective strategies for screening emerge it will be important to understand the quality of life (QOL) effects of participation in ovarian cancer screening. In this study, we examined the effects of participation in an ovarian cancer screening program on worry about cancer risk and QOL. A randomized controlled clinical trial (n = 592) was conducted. Women without a family history suggestive of a BRCA1/2 mutation were randomly assigned to screening and risk counseling, separately and in combination. Results were compared to women randomized to usual care alone. Levels of cancer worry fell for all study groups and QOL was unaffected; no statistically significant differences were found between groups. Increased levels of worry about ovarian cancer at 2‐year follow‐up were found among participants in screening receiving abnormal test results. For those who receive abnormal results, screening may have long‐term effects and increase worry about cancer risk. Further research will be required to examine the possibility that screening reduces worry when women receive only normal, presumably reassuring, results. Copyright © 2007 John Wiley & Sons, Ltd.
Strengthening GLP compliance through internal audits
Authors: Li Henry , Pifat Dominique , Klein Gerald , Petteway Steve 
Published: January 2007

AbstractThe Quality Assurance (QA) strategy for assessing Good Laboratory Practice (GLP) compliance at different testing facilities varies from focusing on study data verification to taking a quality system approach. As a best practice and to ensure overall compliance with GLP regulations, the Quality Assurance Unit (QAU) should perform three types of internal audits: study‐specific, process‐based, and system inspection. These internal audits serve as a tool to ascertain whether a GLP compliance program is functioning correctly. Information gathered from these audits can also be used to provide assistance during the evolution of a new GLP compliance program. As the GLP compliance program matures, internal audits can be a useful mechanism to help maintain compliance and promote continued improvement. Copyright © 2006 John Wiley & Sons, Ltd.
GLP SOPs for equipment calibration and maintenance part 3: process mapping for SOP development
Authors: Colligon Irina , Rosa Michelle 
Published: January 2007

AbstractAsk almost anyone who has been involved in writing Standard Operating Procedures (SOPs) about how they learned to do it and chances are the answer will be that they just sat down and wrote their ideas, maybe using a standard format. Although process flows and flow charts have been an integral part of the computer world for as long as most care to remember, it has only been in the past decade or so that the concepts of process design and process flows have started to enter the realm of SOP development in the pharmaceutical industry. In this installment of the series, we will describe one process design approach to developing SOPs for a laboratory. Copyright © 2006 John Wiley & Sons, Ltd.
A High‐Throughput Methodology for Screening Solution‐Based Chelating Agents for Efficient Palladium Removal
Authors: Flahive Erik , Ewanicki Brigitte , Yu Shu , Higginson Paul D. , Sach Neal W. , Morao Iñaki 
Published: January 2007

AbstractA simple and efficient screening methodology for scavenger reagent identification was carried out to overcome the high levels of residual palladium present in the Axitinib process. The purification strategy relied on crystallization of the desired product from the crude reaction mixture leaving the residual palladium in the mother liquor by using Pd‐chelating agents. Theoretical models based on naïve Bayesian classifier were also performed to support the screening team. Using the best model, a virtual screening of commercially available compounds was conducted and new theoretical hits were generated. Some of these theoretical ligands were then tested experimentally, confirming the validity of our model.
Similarity‐Based Descriptors (SIBAR) as Tool for QSAR Studies on P‐Glycoprotein Inhibitors: Influence of the Reference Set
Authors: Zdrazil Barbara , Kaiser Dominik , Kopp Stephan , Chiba Peter , Ecker Gerhard F. 
Published: January 2007

AbstractPolyspecific proteins, such as the cytochrome P450 enzyme family, the hERG potassium channel and the ABC‐type multidrug efflux pumps ABCB1, ABCC1 and ABCG2 are increasingly recognised as playing a major role in bioavailability and toxicity of drugs. Although considerable efforts have been undertaken to establish in silico tools for predicting drug–protein interactions, especially in the field of ABC pumps, general applicable models are still rare. We recently showed that similarity‐based descriptors are a versatile tool for prediction of ABCB1 (P‐glycoprotein, P‐gp) inhibitory activity. These descriptors are based on the calculation of similarity values between the compounds of the training set to a group of reference set compounds. The similarity values are subsequently used as independent variables in QSAR analyses. Within this paper, we address the influence of the reference set on the predictive ability of QSAR models for a set of 412 inhibitors of the multidrug efflux pump ABCB1. Four different reference sets were designed comprising highly diverse, drug‐like compounds (A), a subset of the training set compounds (B), a set of manually selected ABCB1 inhibitors (C) and low molecular weight chemicals (D). Our results indicate that a combination of high diversity and an interaction of the reference compounds with the biological target is beneficial for yielding good models. The reference dataset tailored to the specific problem (the biological target) scored best in predicting the biological activity of compounds from an external test set.
New possible ionic structures in Wittig reaction: Analysis of stability and rotation barriers by semiempirical PM3 method
Authors: Mracec Maria , Pascariu Aurelia , Berger Stefan , Mracec Mircea 
Published: January 2007

AbstractFor the Wittig reaction between butylidentriphenylphosphorane and benzaldehyde studied previously using NMR spectroscopy, three ionic intermediates have been proposed in order to explain the “stereochemical drift” (different ratio in oxaphosphetane stereoisomers compared with the ratio of the final Z/E olefins). In this paper, the PM3 semiempirical MO method was applied on the proposed ionic intermediates. Two of the ionic intermediates could lead to a shift of the reaction towards the final products, olefins and phosphine oxide, while the third intermediate could be implicated in a retro‐Wittig reaction. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
The interpretation of exposure effect estimates in chronic air pollution studies
Authors: Haneuse S. , Wakefield J. , Sheppard L. 
Published: January 2007

AbstractIn this article we consider the interpretation of regression parameters used to represent ‘chronic’ or ‘long‐term’ air pollution exposure effects. Although scientific interest typically lies in understanding such effects at the level of the individual, studies have generally employed a semi‐ecological design; outcomes and confounder information are collected on individuals while exposure is only available at the aggregate‐or group‐level. A precise interpretation of results from a semi‐ecological design must take into account the aggregated nature, both spatial and temporal, of the exposure measure. The most common analysis approach for assessing chronic exposure effects has been within the Cox proportional hazards model framework; specific analyses are tailored to accommodate the shortcomings of the available exposure information. We revisit the underlying assumptions of the Cox model and discuss the implications of two common aspects of chronic effects studies: time‐dependent exposures and time‐varying effects. Focusing on the consequences of temporal aggregation of exposure, we show that an estimate obtained from a time‐aggregated semi‐ecological design can correspond to very different underlying time‐varying exposure and risk scenarios. Further, distinguishing which of these is correct is not possible from the semi‐ecological data alone. Our goal is to highlight some statistical issues faced by existing studies of chronic air pollution effects, and aid in the development and planning of future studies. Copyright © 2007 John Wiley & Sons, Ltd.
Zur probabilistischen Bemessung von Stahlrahmen
Authors: Křivý Vít , Marek Pavel 
Published: January 2007

AbstractDer Beitrag befaßt sich mit den Möglichkeiten der Zuverlässigkeitsbeurteilung von Stahlrahmen unter Anwendung der SBRA (Simulation‐Based Reliability Assessment)‐Methode, die in [1] beschrieben ist. Die ständige Verbesserung der Computertechnik macht es möglich, das Potential der SBRA‐Methode nicht nur für die Analyse einfacher Tragwerke und ihrer Komponenten, sondern auch für die Beurteilung von komplizierten, statisch unbestimmten Konstruktionen, wie z. B. Stahlrahmen, anzuwenden.In diesem Zusammenhang wird ein möglicher Übergang von der traditionellen und in den derzeitigen Normen angewendeten Beurteilung der Knickstabilität von Stahlrahmen (die auf der Bestimmung von Knicklängen und Knickzahlen beruht) zu der auf der SBRA‐Methode und der Analyse nach Theorie II. Ordnung gegründete Festigkeitsauffassung über Stabilität, vorgestellt.
Methodik zur Beurteilung des Brandverhaltens von Metallkonstruktionen
Authors: Skowroński Wojciech 
Published: January 2007

AbstractIm vorliegenden Beitrag wird eine Methodik zur Brandbemessung von Metallkonstruktionen unter Temperatureinwirkung vorgeschlagen, die zeitabhängige Effekte berücksichtigt und gleichzeitig ermöglicht, einen Einfluß der Erwärmungsgeschwindigkeit auf den Tragfähigkeitverlust der Konstruktion zu berücksichtigen. Eine Aufklärung über zeitabhängige Effekte ist unabdingbar, wenn eine Bemessung unter Berücksichtigung von Brandtemperaturanstiegskurven notwendig ist. Solche Differenzierungen wurden international im Eurocode 1 festgelegt, aber sie werden wegen fehlender Methodik zum Tragfähigkeitsnachweis bisher nicht bei der Bemessung von Metallkonstruktionen im Brandfall angewandt. Die Brandbemessung müßte auf einer begründeten Wahl einer konkreten Temperatur‐Zeit‐Kurve, die mehr oder weniger intensiven Brand beschreibt, und auf konsequent durchgeführten Berechnungen zum Tragfähigkeitsnachweis beruhen, die es ermöglichen den Einfluß der Erwärmungsgeschwindigkeit auf das Verhalten der Konstruktion zu berücksichtigen.
Interference analysis and capacity for forward link 3G CDMA network with adaptive antennas
Authors: Kavak Adnan , Karakoç Mustafa , Torlak Murat , Ozdemir Caner 
Published: January 2007

AbstractIn code division multiple access (CDMA) systems, the capacity of forward link (FL) communication to mobile receivers is limited primarily by co‐channel interference (CCI). Adaptive antenna arrays (AAAs) that use antenna arrays along with advanced signal processing at the base station (BS) have been proposed to mitigate this limitation. For a 3G CDMA cellular network, where each BS equipped with an AAA serves mixture of voice and data users within its coverage, we study FL capacity and investigate the effects of different factors (array topology, multipath angle spread, data rate, and beamforming algorithm) on this capacity under Rayleigh fading channel. By modeling the instantaneous signal‐to‐interference power ratio received at the mobile, we derive the system outage equation that considers blocking of either desired voice or data user. Simulation results show that for the same element spacing and number of antenna elements per cell, the uniform circular array (UCA) topology results in larger capacity than the sectorized uniform linear array (ULA) topology does, and that a larger angle spread or data user rate reduces FL capacity. Copyright © 2007 John Wiley & Sons, Ltd.
A new authentication protocol based on pointer forwarding for mobile communications
Authors: Lee Cheng‐Chi , Hwang Min‐Shiang , Liao I‐En 
Published: January 2007

AbstractA frequently moving mobile user in GSM must re‐register at the HLR frequently, and, therefore, the signaling traffic is overhead and HLR database update cost raised. In this paper, the authors propose a new authentication protocol, based on pointer forwarding to reduce the HLR update cost and traffic load for the MS authentication protocol. The proposed protocol for GSM can achieve some objectives described in Introduction. Compared with other authentication protocols, our protocol is efficient. Copyright © 2007 John Wiley & Sons, Ltd.
Habitat preferences of an endangered insect species, Cepero's ground‐hopper (Tetrix ceperoi)
Authors: Gröning Julia , Krause Sascha , Hochkirch Axel 
Published: January 2007

AbstractPreventing the global decline in biodiversity is a major task for conservation biologists. Although habitat loss has been identified as a key factor driving extinction processes, our knowledge on the habitat requirements of many endangered species, particularly invertebrates, is still sparse. We present a feasible method to study the microhabitat preferences of insect species. In Central Europe, the endangered Cepero's ground‐hopper, Tetrix ceperoi, is believed to have its only remaining natural habitats in dune slacks of the Wadden Sea Islands. Our results suggest that this species performs an active habitat choice of damp, bare patches with high temperatures. While ponds and fens in dune slacks provide large areas of damp bare ground and algal mats, grasslands, degraded dune slacks and the transitional zone between salt marsh and dunes are less suited as habitats. The major threat for T. ceperoi is found in the succession of its pioneer habitats due to the reduced natural dynamics. In industrialized countries, pioneer habitats and species are threatened substantially by coastal protection and floodplain regulation. This is only compensated in part by anthropogenic creation of secondary habitats, such as different kinds of pits or coal heaps. Nevertheless, there is a strong need for restoration of dynamic habitats by floodplain revitalization and dune slack restoration.