bluuebunny/crossref_metadata_2025_split huggingface dataset:
Titanium Complexes Stabilized by a Sulfur‐Bridged Chelating Bis(aryloxo) Ligand as Active Catalysts for Olefin Polymerization
Authors: Janas Zofia , Jerzykiewicz Lucjan B. , Przybylak Katarzyna , Sobota Piotr , Szczegot Krzysztof 
Published: March 2004

AbstractThe mixed‐ligand complexes [Ti2(μ‐OR)2(OR)2(κ3‐tbop)2] (1a) for R = Me and (1b) R = Et were prepared by the reaction of Ti(OR)4 and H2tbop {H2tbop = 2,2′‐thiobis[4‐(1,1,3,3‐tetramethylbutyl)phenol]} in methanol. Treatment of 1a and 1b with AlMe3 led to the substitution of terminal alkoxy groups to create the organometallic compounds [Ti2(μ‐OR)2(κ3‐tbop)2(Me)2] (2a) for R = Me and (2b) for R = Et. Controlled hydrolysis of 2b causes the evolution of methane and the formation of the titanoxane compounds [{Ti2(μ‐OEt)2(κ3‐tbop)2}2(μ‐O)2]·2CH2Cl2 (3). Structures of 1a, 1b, 2a, 2b, and 3 were confirmed by NMR spectroscopy; 1b and 3 were further investigated with X‐ray crystallography. Compounds 1a, 1b, 2a, and 2b were supported on MgCl2 and when activated with aluminum alkyls, found to effectively polymerize ethylene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Absorption, Magnetic Circular Dichroism, IR Spectra, Electrochemistry, and Molecular Orbital Calculations of Monoaza‐ and Opposite Diazaporphyrins
Authors: Ogata Hiroshi , Fukuda Takamitsu , Nakai Katsunori , Fujimura Yuichi , Neya Saburo , Stuzhin Pavel A. , Kobayashi Nagao 
Published: March 2004

AbstractElectronic absorption, magnetic circular dichroism (MCD), IR spectra, and cyclic and differential pulse voltammograms of metal‐free and copper monoaza‐ and opposite diazaporphyrins are reported, together with molecular orbital (MO) calculations using the density functional theory (DFT) method. Introduction of nitrogen atoms at the meso position of porphyrins caused a blue‐shift of the B band and a red‐shift of the Q band, with a concomitant decrease and increase of the apparent absorption coefficient, respectively. On going from monoaza to diaza species, the apparent bandwidth at half‐height of the B band and the splitting of the Q band do not change significantly for metal‐free species, but increase for the copper species. The MCD peaks and troughs correspond closely to the peaks of the absorption spectra, so that these are interpreted as the superimposition of Faraday B terms. The MCD sign pattern (minus‐to‐plus on going from longer to shorter wavelengths) substantiates experimentally that the splitting between the HOMO and HOMO−1 orbital is larger than that between the LUMO and LUMO+1. Of the copper complexes of octaethylporphyrin (OEP), monoaza‐ (MAP), diaza‐ (DAP) and tetraazaporphyrins (TAP), CuTAP is the easiest to reduce and hardest to oxidize. The potential differences between the first oxidation and reduction couples were about 2.1−2.4 V. MO calculations using DFT succeeded in reproducing some of the above spectroscopic and electrochemical characteristics. In addition, some of the IR bands were assigned on the basis of the DFT calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Assessment of the sensitivity of the computational programs DEREK, TOPKAT, and MCASE in the prediction of the genotoxicity of pharmaceutical molecules
Authors: Snyder Ronald D. , Pearl Greg S. , Mandakas George , Choy Wai Nang , Goodsaid Federico , Rosenblum I.Y. 
Published: March 2004

AbstractComputational models are currently being used by regulatory agencies and within the pharmaceutical industry to predict the mutagenic potential of new chemical entities. These models rely heavily, although not exclusively, on bacterial mutagenicity data of nonpharmaceutical‐type molecules as the primary knowledge base. To what extent, if any, this has limited the ability of these programs to predict genotoxicity of pharmaceuticals is not clear. In order to address this question, a panel of 394 marketed pharmaceuticals with Ames Salmonella reversion assay and other genetic toxicology findings was extracted from the 2000–2002 Physicians' Desk Reference and evaluated using MCASE, TOPKAT, and DEREK, the three most commonly used computational databases. These evaluations indicate a generally poor sensitivity of all systems for predicting Ames positivity (43.4–51.9% sensitivity) and even poorer sensitivity in prediction of other genotoxicities (e.g., in vitro cytogenetics positive; 21.3–31.9%). As might be expected, all three programs were more highly predictive for molecules containing carcinogenicity structural alerts (i.e., the so‐called Ashby alerts; 61% ± 14% sensitivity) than for those without such alerts (12% ± 6% sensitivity). Taking all genotoxicity assay findings into consideration, there were 84 instances in which positive genotoxicity results could not be explained in terms of structural alerts, suggesting the possibility of alternative mechanisms of genotoxicity not relating to covalent drug‐DNA interaction. These observations suggest that the current computational systems when applied in a traditional global sense do not provide sufficient predictivity of bacterial mutagenicity (and are even less accurate at predicting genotoxicity in tests other than the Salmonella reversion assay) to be of significant value in routine drug safety applications. This relative inability of all three programs to predict the genotoxicity of drugs not carrying obvious DNA‐reactive moieties is discussed with respect to the nature of the drugs whose positive responses were not predicted and to expectations of improving the predictivity of these programs. Limitations are primarily a consequence of incomplete understanding of the fundamental genotoxic mechanisms of nonstructurally alerting drugs rather than inherent deficiencies in the computational programs. Irrespective of their predictive power, however, these programs are valuable repositories of structure‐activity relationship mutagenicity data that can be useful in directing chemical synthesis in early drug discovery. Environ. Mol. Mutagen. 43:143–158, 2004. © 2004 Wiley‐Liss, Inc.
Biomagnetic fluid flow in a 3D rectangular duct
Authors: Tzirtzilakis1 E. E. , Sakalis V. D. , Kafoussias N. G. , Hatzikonstantinou P. M. 
Published: March 2004

AbstractThe laminar, incompressible, three‐dimensional, fully developed viscous flow of a non‐conducting biomagnetic fluid in a impermeable rectangular duct is numerically studied in the presence of an applied magnetic field. It is assumed that the magnetic field strength is sufficiently strong to saturate the biofluid and the magnetization is given as a function of the magnetic field intensity. The system of the partial differential equations, resulting after the introduction of appropriate non‐dimensional variables, is solved applying an efficient numerical technique based on a pressure‐linked pseudotransient method on a common grid. Results concerning the existence and the uniqueness of the solution, are also given. The obtained results, for different values for the parameters entering into the problem under consideration, show that the flow is appreciably influenced by the presence of the magnetic field. Copyright © 2004 John Wiley & Sons, Ltd.
Analysis of hypersonic flows using finite elements with Taylor–Galerkin scheme
Authors: Kessler Martin P. , Awruch Armando M. 
Published: March 2004

AbstractThe aim of the present work is to introduce a formulation for the numerical analysis of three‐dimensional thermochemical non‐equilibrium hypersonic flows, using the finite element method and the Taylor–Galerkin scheme and adopting Park's 2‐temperature, 5‐species (N2, O2, NO, N and O) and 17‐reaction model. Examples using Euler and Navier–Stokes equations are included and compared with experimental and numerical works presented by other authors. The results are close to those analysed by other researches and a good computational performance was obtained. Copyright © 2004 John Wiley & Sons, Ltd.
Dominant negative Ras enhances lactogenic hormone‐induced differentiation by blocking activation of the Raf–Mek–Erk signal transduction pathway
Authors: Cerrito Maria Grazia , Galbaugh Traci , Wang Weihan , Chopp Treasa , Salomon David , Cutler Mary Lou 
Published: March 2004

AbstractEpidermal growth factor (EGF) and Ras mitogenic signal transduction pathways are frequently activated in breast carcinoma and inhibit mammary differentiation and apoptosis. HC11 mouse mammary epithelial cells, which differentiate and synthesize β‐casein following growth to confluency and stimulation with lactogenic hormones, were used to study EGF‐dependent signaling during differentiation. Blocking Mek–Erk or phosphotidylinositol‐3‐kinase (PI‐3 kinase) signaling with specific chemical inhibitors enhanced β‐casein promotor‐driven luciferase activity. Because EGF stimulation of HC11 cells resulted in the activation of Ras, the effect of activated Ras (RasV12) or dominant negative (DNRasN17) on lactogen induced differentiation was examined. HC11 cell lines expressing RasV12 or DNRasN17 under the control of a tetracycline (tet)‐responsive promotor were constructed. Activated RasV12 expression resulted in reduced tyrosine phosphorylation of Stat5 and a delay in β‐casein expression in response to prolactin. However, the expression of tet‐regulated DNRasN17 and adenovirus‐encoded DNRasN17 enhanced Stat5 tyrosine phosphorylation, Stat5 DNA binding, and β‐casein transcription. The expression of DNRasN17 blocked the activation of the Mek–Erk pathway by EGF but did not prevent the phosphorylation of AKT, a measure of activation of the PI‐3‐kinase pathway. Moreover, the expression of DNRasN17 prevented the block to lactogenic differentiation induced by EGF. Stimulation of HC11 cells with prolactin resulted in the association of the SHP2 phosphatase with Stat5, and this association was prevented by DNRasN17 expression. These results demonstrate that in HC11 cells DNRas inhibits the Mek–Erk pathway and enhances lactogenic hormone‐induced differentiation. This occurs, in part, by inhibiting the association of the SHP2 phosphatase with Stat5. Published 2004 Wiley‐Liss, Inc.
An engineered EBV vector expressing human factor VIII and von Willebrand factor in cultured B‐cells
Authors: Basu Utpal , Banerjee Subrata 
Published: March 2004

AbstractBackgroundHemophilia A is a congenital disorder caused by a deficiency of the blood‐clotting factor VIII (FVIII) and is an attractive candidate for gene therapy. Most of the studies have only explored the potential of hepatocytes and muscle cells as the targets for gene transfer. Attempts to transfer the genes into hematopoietic cells have so far been mostly unsuccessful due to inefficiency of most viral vectors to transduce these cells and the supposed inability of the cells to express FVIII.MethodsWe demonstrate the generation of an engineered Epstein‐Barr virus (EBV) vector with a BAC backbone that has the unique capacity to carry either the full‐length FVIII cDNA or its B‐domain‐deleted form; a modified version of the vector that carries B‐domain‐deleted FVIII along with the von Willebrand factor (vWF) cDNA or the reporter gene DsRed2 was also used. All these vectors have been safety modified with viral thymidine kinase cDNA to transduce human B‐cells in culture.ResultsLow‐level expression of FVIII in the order of 5–8 ng FVIIIC/ml were observed in the cells stably transduced with full‐length FVIII, while cells with the B‐domain‐deleted version expressed 8–16 ng FVIIIC/ml. Expression of vWF and B‐domain‐deleted FVIII resulted in a moderate expression of 18–30 ng FVIIIC/ml. Long‐term expression for 12–16 weeks was observed in these cells regardless of selection pressure.ConclusionsThese results support the development of an episomal engineered EBV vector for treatment of hemophilia A using the hematopoietic cells as a target for providing immediate secretion of functionally active product in the circulating bloodstream. Copyright © 2004 John Wiley & Sons, Ltd.
Organ‐specific expression of the lacZ gene controlled by the opsin promoter after intravenous gene administration in adult mice
Authors: Zhu Chunni , Zhang Yun , Zhang Yu‐feng , Yi Li Jian , Boado Ruben J. , Pardridge William M. 
Published: March 2004

AbstractBackgroundThe tissue‐specific expression of an exogenous gene, under the influence of a tissue‐specific promoter, has been examined in the past with pro‐nuclear injections of the transgene and the development of transgenic mouse models. ‘Adult transgenics’ is possible with the acute expression of an exogenous gene that is administered to adult animals, providing the transgene can be effectively delivered to distant sites following an intravenous administration.MethodsThe organ specificity of exogenous gene expression in adult mice was examined with a bacterial β‐galactosidase (LacZ) expression plasmid under the influence of the bovine rhodopsin gene promoter. The 8‐kb plasmid DNA was delivered to organs following an intravenous administration with the pegylated immunoliposome (PIL) non‐viral gene transfer technology. The PIL carrying the gene was targeted to organs with the rat 8D3 monoclonal antibody (MAb) to the mouse transferrin receptor (TfR).ResultsThe rhodopsin/β‐galactosidase gene was expressed widely in both the eye and the brain of adult mice, but was not expressed in peripheral tissues, including liver, spleen, lung, or heart. Ocular expression included the retinal‐pigmented epithelium, the iris, and ciliary body, and brain expression was observed in neuronal structures throughout the cerebrum and cerebellum.ConclusionsThe expression of trans‐genes in adult animals is possible with the PIL non‐viral gene transfer method. The opsin promoter enables tissue‐specific gene expression in the eye, as well as the brain of adult mice, whereas gene expression in peripheral tissues, such as liver or spleen, is not observed. Copyright © 2004 John Wiley & Sons, Ltd.
Wider impacts of microfinance institutions: issues and concepts
Authors: Zohir Sajjad , Matin Imran 
Published: March 2004

AbstractThe paper distinguishes between a ‘wider’ definition of wider impacts (which takes into account feedbacks from impacts to institutional performance) and a ‘narrower’ definition, which does not. In respect of both definitions, the paper sets out a typology of the effects which need to be measured (cultural, economic, social and political) and of the levels at which each of these impacts needs to be assessed (local, regional and national). The purpose is not to set out a blueprint for specific studies but rather to offer a framework which may be useful for guiding the methodology of such studies. Copyright © 2004 John Wiley & Sons, Ltd.
Quantitative approach to impact analysis of microfinance programmes in Bangladesh—what have we learned?
Authors: Khalily M. A. Baqui 
Published: March 2004

AbstractThe quantitative impact assessment of microfinance programmes, like the programmes themselves, originated in Bangladesh. This essay reflects on the significance and usefulness for present day researchers of the analytical advances made in Bangladesh since the beginning of the 1990s. Particularly in the area of selection bias, fungibility and the assessment of wider impacts, it argues, those advances are crucial, and need to be borne in mind by all practitioners; but financial sustainability remains an unresolved problem. Copyright © 2004 John Wiley & Sons, Ltd.
The wider impacts of BRAC poverty alleviation programme in Bangladesh
Authors: Chowdhury A. Mushtaque R. , Bhuiya Abbas 
Published: March 2004

AbstractOver the decades of the 1980s and 90s many poverty alleviation programmes have been implemented in developing countries. Evaluations of such programmes have traditionally looked at their success in increasing the income levels of participants but less at the wider goals of human well‐being. This paper looks at the poverty alleviation programme of BRAC, a large non‐governmental organisation in Bangladesh, and, based on carefully designed studies, presents its impact on selected components of ‘human well‐being’.This study found better child survival and nutritional status in households served by the programme. Simular impacts were also found in other areas such as expenditure patterns, family planning practices and children's education. The studies also looked at the impact on the rural power structure and found a substantial change in the networking relationship of health providers. The likely influence of ‘selectivity bias’ on the above results is also discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Mapping cognitions to better understand attitudinal and behavioral responses in appraisal research
Authors: Wright Robert P. 
Published: March 2004

AbstractPerceptions are important in determining performance appraisal system success. The growing body of research in this area has clearly documented the differences in perceptions between appraisers and appraisees. However, many of these findings are predominately based on aspects of the system in judging its overall effectiveness and rely heavily on self‐report questionnaire responses with weak methodological rigor. Not much is known about the deeper cognitive perceptions of appraisers and appraisees in better explaining their attitudinal and behavioral outcomes. This paper breaks away from conventional questionnaire‐generated perceptions and applies a unique clinical cognitive mapping methodology called the repertory grid technique to elicit the personal constructs of how real respondents perceive appraisal systems based on their real‐life experiences. The method allowed the investigation to go much deeper than past research into the core perceptions that influenced respondents' attitudes and subsequent behaviors. Though the findings showed some commonality in personal constructions of appraisal systems with those found in the literature, new constructs, core perceptual dimensions, and collective cognitive maps were elicited for the very first time, opening up new questions and issues for further research. Implications to theory and practice are also discussed. Copyright © 2004 John Wiley & Sons, Ltd.
General self‐efficacy and self‐esteem: toward theoretical and empirical distinction between correlated self‐evaluations
Authors: Chen Gilad , Gully Stanley M. , Eden Dov 
Published: March 2004

AbstractTo test whether general self‐efficacy and self‐esteem relate differently to motivational and affective constructs, we collected data from samples in academic and work settings. Results suggest that general self‐efficacy is more highly related to motivational variables than is self‐esteem, whereas self‐esteem is more highly related to affective variables than is general self‐efficacy, as hypothesized. Furthermore, results support the notion that motivational and affective states differentially mediate the relationships of general self‐efficacy and self‐esteem with task performance. These results confirm the theoretical distinction between general self‐efficacy and self‐esteem and suggest that failure to distinguish between them might exact a price in terms of precision, validity, and understanding of determinants of performance. Implications for research and practice in organizations are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
The customer is not always right: customer aggression and emotion regulation of service employees
Authors: Grandey Alicia A. , Dickter David N. , Sin Hock‐Peng 
Published: March 2004

AbstractResearch on work aggression or anger has typically focused on supervisors and co‐workers as the instigators of aggression; however, aggressive customers are also likely and may have unique consequences for the employee. We explore this phenomenon with a sample of 198 call center employees at two work sites. The employees reported that customer verbal aggression occurred 10 times a day, on average, though this varied by race and negative affectivity. Using LISREL, our data indicated that both the frequency and stress appraisal of customer aggression positively related to emotional exhaustion, and this burnout dimension mediated the relationship of stress appraisal with absences. Stress appraisal also influenced employees' emotion regulation strategies with their most recent hostile caller. Employees who felt more threatened by customer aggression used surface acting or vented emotions, while those who were less threatened used deep acting. Job autonomy helped explain who found these events more stressful, and implications of these results are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Networking behaviors and career outcomes: differences for men and women?
Authors: Forret Monica L. , Dougherty Thomas W. 
Published: March 2004

AbstractEngaging in networking behaviors, by attempting to develop and maintain relationships with others who have the potential to provide work or career assistance, is considered to be an important career management strategy. This study explores the relationship between networking behavior and career outcomes (i.e., number of promotions, total compensation, perceived career success) in a sample of managerial and professional employees. Furthermore, we investigate whether networking behavior is as beneficial for women as it is for men. Results indicated that some types of networking behavior were related to both objective and perceived career outcomes. In addition, gender differences do impact the utility of networking behavior as a career‐enhancing strategy. Explanations of our results and implications for engaging in networking behavior are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Soil N transformations after application of 15N‐labeled biomass in incubation experiments with repeated soil drying and rewetting
Authors: Olfs Hans‐Werner , Neu Anni , Werner Wilfried 
Published: March 2004

AbstractThe effects of repeated soil drying and rewetting on microbial biomass N (Nbio) and mineral N (Nmin) were measured in incubation experiments simulating typical moisture and temperature conditions for soils from temperate climates in the post‐harvest period. After application of in vitro 15N‐labeled fungal biomass to a silty loam, one set of soils was exposed to two drying‐rewetting cycles (treatment DR; 14 days to decrease soil moisture to 20 % water‐holding capacity (WHC) and subsequently 7 days at 60 % WHC). A control set (treatment CM) was kept at constant moisture conditions (60 % WHC) throughout the incubation. Nbio and Nmin as well as the 15N enrichment of these N pools were measured immediately after addition of 15N‐labeled biomass (day 0) and after each change in soil moisture (day 14, 21, 35, 42). Drying and rewetting (DR) resulted in higher Nmin levels compared to CM towards the end of the incubation. Considerable amounts of Nbio were susceptible to mineralization as a result of soil drying (i.e., drying enhanced the turnover of Nbio), and significantly lower Nbio values were found for DR at the end of each drying period. Immediately after biomass incorporation into the soil (day 0), 22 % of the applied 15N was found in the Nmin pool. Some of this 15Nmin must have been derived from dead cells of the applied microbial biomass as only about 80 % of the microbes in the biomass suspension were viable, and only 52 % of the 15Nbio was extractable (using the fumigation‐extraction method). The increase in 15Nmin was higher than for unlabeled Nmin, indicating that added labeled biomass was mineralized with a higher rate than native biomass during the first drying period. Overall, the effect of drying and rewetting on soil N turnover was more pronounced for treatment DR compared to CM during the second drying‐rewetting cycle, resulting in a higher flush of mineralization and lower microbial biomass N levels.