bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of Redox Properties of Different PtSn/Al2O3 Catalysts
Authors: Olivier‐Fourcade Josette , Womes Manfred , Jumas Jean‐Claude , Le Peltier Fabienne , Morin Stéphane , Didillon Blaise 
Published: November 2004

AbstractAlumina‐supported Sn and PtSn particles are studied by 119Sn Mössbauer spectroscopy after oxidation and reduction under various conditions. The observed species of SnIV, SnII and Sn0 are grouped in several categories, each being characterised by distinct structural properties. Tin phases in contact with the support or with platinum are identified. The results are used to establish a model describing the phase transformations occurring in PtSn particles under oxidising or reducing conditions. Particular attention is paid to the reduction/reoxidation mechanisms governing H2/O2 double titrations. An increased reactivity of tin towards oxygen, induced by the contact with platinum, is demonstrated. It is shown that tin contributes to the oxygen uptake VO1 of a first titration cycle by platinum‐catalysed transformation of SnII into an oxometallic phase PtxSn(O). The oxygen titre VO2 of a second cycle is due to O2 chemisorption on platinum only.
Oxygenolysis of Flavonoid Compounds: DFT Description of the Mechanism for Quercetin
Authors: Fiorucci Sébastien , Golebiowski Jerôme , Cabrol‐Bass Daniel , Antonczak Serge 
Published: November 2004

AbstractFlavonoids are naturally occurring phenol derivatives present in substantial amounts in a large variety of plants, fruits and vegetables daily eaten by humans. Most of these compounds exhibit several interesting biological activities, such as antiradical and antioxidant actions. Indeed, by complexation with specific enzymes, flavonoids are notably liable to metabolize molecular dioxygen. On the basis of experimental results describing oxygenolysis of the flavonoid quercetin, activated by the enzyme quercetin 2,3‐dioxygenase (2,3‐QD), our attention has focused on the role of metal center in the activation of the substrate quercetin. Thus, in the present study, by means of DFT calculations at the B3LYP/6‐31(+)G* level on model molecular systems, we describe different mechanisms for dioxygen metabolization by quercetin. Stationary points are described, and energetic and structural analyses along the reaction paths are reported. Our calculations show that the copper cation must act as an oxidant towards the substrate and that the reaction proceeds through a 1,3‐cycloaddition.
Ligand Dynamics in Myoglobin: Calculation of Infrared Spectra for Photodissociated NO
Authors: Nutt David R. , Meuwly Markus 
Published: November 2004

AbstractWe present molecular dynamics simulations of the photodissociated state of MbNO performed at 300 K using a fluctuating charge model for the nitric oxide (NO) ligand. After dissociation, NO is observed to remain mainly in the centre of the distal haem pocket, although some movement towards the primary docking site and the xenon‐4 pocket can be seen. We calculate the NO infrared spectrum for the photodissociated ligand within the haem pocket and find a narrow peak in the range 1915–1922 cm−1. The resulting blue shift of 1 to 8 cm−1 compared to gas‐phase NO is much smaller than the red shifts calculated and observed for carbon monoxide (CO) in Mb. A small splitting, due to NO in the xenon‐4 pocket, is also observed. At lower temperatures, the spectra and conformational space explored by the ligand remain largely unchanged, but the electrostatic interactions with residue His64 become increasingly significant in determining the details of the ligand orientation within the distal haem pocket. The investigation of the effect of the L29F mutation reveals significant differences between the behaviour of NO and that of CO, and suggests a coupling between the ligand and the protein dynamics due to the different ligand dipole moments.
Random‐effects Cox proportional hazards model: General variance components methods for time‐to‐event data
Authors: Pankratz V. Shane , de Andrade Mariza , Therneau Terry M. 
Published: November 2004

AbstractProportional hazards regression models are commonly used to study factors associated with time‐to‐event data. Because many complex genetic diseases exhibit variation in age at onset, it is important to have the capability to perform survival analyses on data collected from individuals whose observations are correlated due to shared genes or environment. While there are widely accepted methods for variance components analysis for simple quantitative traits, a parallel methodology for survival data has not been available. This manuscript outlines a method to perform variance component analyses under general random effects proportional hazards models. This method is based on a Laplace approximation, and makes computation for correlated time‐to‐event data feasible. The correlated frailty models described here can be used to perform genetic analyses, and other analyses with structured random effects, on age‐at‐onset data in a manner analogous to standard variance components methods for quantitative traits. We illustrate the use of the method by examining the heritability of breast cancer in a large familial cohort study. We also perform variance components linkage analyses on data simulated for the Twelfth Genetic Analysis Workshop (GAW12), and further examine the performance of this method for linkage analysis in a simulation study. The breast cancer analyses support significant heritability of disease age‐at‐onset that is of moderate size. The variance component linkage analyses successfully identify the location of the disease genes that were simulated to have a direct impact on age‐at‐onset. The methods outlined here make it possible to perform general variance components analyses on time‐to‐event endpoints, even on large data sets, in a computationally efficient manner.Genet. Epidemiol.28:97–109, 2005. © 2004 Wiley‐Liss, Inc.
Religious attendance and depressive symptoms among community dwelling elderly in Taiwan
Authors: Hahn Cheng‐Yi , Yang Mei‐Sang , Yang Ming‐Jen , Shih Chun‐Hua , Lo Hsin‐Yi 
Published: November 2004

AbstractBackgroundThe purpose of this study was to investigate the unique association between religious attendance and the prevalence of depressive symptoms among community dwelling elderly persons.MethodsEmploying a multilevel stratified sampling strategy, a total of 1000 subjects, aged 65–74 and living in Taiwan, were recruited for this interview survey during the year 2001. Aside from background information, the Taiwanese Depression Questionnaire (TDQ) and the Neighborhood Quality Index were used to assess degree of depression and its correlates.ResultsAltogether, 863 subjects (age, M = 69.4, SD = 2.7) had complete data for analysis; 215 (24.8%) had had depressive symptoms in the past week. Among them, those who were female, (OR = 2.17, 95% CI = 1.59–2.97), illiterate(OR = 2.42, 95% CI = 1.76–3.33), unemployed (OR = 1.80, 95% CI = 1.24–2.61), or not married (OR = 1.71, 95% CI = 1.22–2.38), or those who had less family income (OR = 1.84, 95% CI = 1.24–2.73), physical illness (OR = 2.68, 95% CI = 1.86–3.86), or less social capital (OR = 0.91, 95% CI = 0.88–0.94), were at higher risk of being depressed. Moreover, those (95.2% with religious belief ) who had not attended religious activities during the past 6 months were at higher risk of being depressed than those (100% with religious belief ) who had (OR = 2.63, 95% CI = 1.41–4.91). Multivariate logistic regression disclosed that those never attending religious activities were 2.70 times more likely to be depressed when compared to those who had, after taking into consideration sociodemographics and social capital.ConclusionThe attending of religious activities is a protective factor for geriatric depression. Copyright © 2004 John Wiley & Sons, Ltd.
Older people with schizophrenia: a community study in a rural catchment area
Authors: Rodriguez‐Ferrera Silvia , Vassilas Christopher A. , Haque Sayeed 
Published: November 2004

AbstractBackgroundAn increasing number of older people with schizophrenia are living in the community but we still have little data on their clinical presentation, service use and functioning.MethodsAll patients over the age of 60 years with a primary diagnosis of a non‐affective psychotic disorder who were known to health services were identified in a rural area of East England. Subjects were interviewed with the Present State Examination and other standardised interview instruments.ResultsSeventy‐two subjects fulfilled study inclusion criteria. Forty‐six of these had first become ill before the age of 60 years and 26 after (the very late onset group (VLO)). Eighty per cent were women and 26% had never married. Eighty‐seven per cent lived in their own homes and 51% alone. In the preceding month, 41% of the sample had experienced psychotic symptoms and 15% depressive symptoms. Twenty‐seven per cent of the sample were cognitively impaired. The earlier onset group had significantly higher rates of tardive dyskinesia and negative symptoms of schizophrenia and were treated with higher doses of neuroleptics. The VLO group had higher rates of hearing impairment (54% vs 15% p = 0.001) and of partial or no insight (93% vs 55% p = 0.004).ConclusionsDespite significant differences in presentation, elderly patients with schizophrenia and very late onset schizophrenia‐like psychosis have much in common. Both groups are vulnerable with high levels of psychopathology, poor insight, sensory impairment and social isolation. The needs of older people with schizophrenia must be taken into account when services for older adults are planned. Copyright © 2004 John Wiley & Sons, Ltd.
Paternal involvement in child caregiving and infant sociability
Authors: Frascarolo France 
Published: November 2004

AbstractIn this study, the influence of paternal involvement in caregiving on infant sociability was assessed using a “strange situation” paradigm adapted from the work of Ainsworth, Blehar, Waters, and Wall (1978). Thirty‐seven families participated with their firstborn child (aged 12–14 months). According to the questionnaire, 20 “nontraditional” fathers were very involved in caretaking, and 17 fathers were less or not at all involved. Infant sociability was assessed using three of Ainsworth et al.'s rating scales: proximity or contact‐seeking, avoidance, and distance interaction. Results indicated that infants of nontraditional fathers were globally more sociable with all their partners (father, mother, and stranger) than infants of traditional fathers. Furthermore, results suggested that it was not only the father–infant relationship or infant development which were affected by the amount of paternal involvement in daily caretaking but the family system as a whole. Indeed, infants from nontraditional families appeared to interact equally with their fathers and mothers in direct interaction. In addition, these infants interacted at a distance with a “stranger” as much in the presence of their fathers as in the presence of their mothers, thereby suggesting that both parents represented an equally secure base.
Temporal changes in the affective experience of new fathers and their spouses
Authors: Kaitz Marsha , Katzir Daphna 
Published: November 2004

AbstractOur aim was to study temporal changes in fathers' affective experience during the first year of parenthood. For comparison, data also were collected from their spouses. Fifty‐five Israeli couples comprised the initial sample, and both partners were interviewed during the prepartum period and at 3, 6, and 12 months' postpartum. Measures of emotionality, positive affect, negative affect, and mood regarding self, infant, and spouse/marriage were derived by finely coding parents' answers to interview questions. Analyses show that, for fathers and mothers, time effects were most substantial between the prepartum period and 3 months postpartum, and most of the changes were in a positive direction. Fathers and mothers showed continuity in positive affect and in negative affect, respectively. Overall, the sample experienced heightened positive affect and more positive moods after the birth of their infant than prior to it.
Colic and fussing in infancy, and sensory processing at 3 to 8 years of age
Authors: DeSantis Andrea , Coster Wendy , Bigsby Rosemarie , Lester Barry 
Published: November 2004

AbstractThe purpose of this follow‐up study was to examine whether a group of 28 clinic‐referred infants with colic, excessive crying, or both at 4 to 12 weeks demonstrated sensory processing, coping, and behavioral/attention regulation difficulties at 3 to 8 years of age. Seventy‐five percent of the sample demonstrated atypical behavioral responses to sensory experiences. Hours of fussing during infancy significantly correlated with inattention, emotional reactivity, touch processing, environmental coping, and externalizing behavior at 3 to 8 years, but not hours of crying. The most striking result was that children with more hours of early fussing showed less efficient sensory processing, poorer coping with the environment, and more attention/hyperactivity problems compared to those with less hours of fussing. Results suggest that hours of fussing rather than crying could be an early marker for infants at risk.
Determination of bromazepam in human plasma by high‐performance liquid chromatography with electrospray ionization tandem mass spectrometric detection: application to a bioequivalence study
Authors: Andraus Maristela H. , Wong Anthony , Silva Ovandir A. , Wada Cicília Y. , Toffleto Odaly , Azevedo Cristina P. , Salvadori Myriam C. 
Published: November 2004

AbstractA simple method using a one‐step liquid–liquid extraction (LLE) followed by high‐performance liquid chromatography (HPLC) with positive ion electrospray ionization tandem mass spectrometric (ESI‐MS/MS) detection was developed for the determination of bromazepam in human plasma, using lorazepam as internal standard. The acquisition was performed in the multiple reaction monitoring mode, monitoring the transitions: m/z 316 > 182 for bromazepam and m/z 321 > 275 for lorazepam. The method was linear over the studied range (1–100 ng ml−1), with r2 > 0.98, and the run time was 2.5 min. The intra‐ and inter‐assay precisions were 2.7–14.6 and 4.1–17.3%, respectively and the intra‐ and inter‐assay accuracies were 87–111 and 75.8–109.5%, respectively. The mean recovery was 73.7%, ranging from 64.5 to 79.7%. The limit of quantification was 1 ng ml−1. At this concentration the mean intra‐ and inter‐assay precisions were 14.6 and 7.1%, respectively, and the mean intra‐ and inter‐assay accuracies were 102.5 and 104%, respectively. Bromazepam stability was evaluated and the results showed that the drug is stable in standard solution and in plasma samples under typical storage and processing conditions. The method was applied to a bioequivalence study in which 27 healthy adult volunteers (14 men) received single oral doses (6 mg) of reference and test bromazepam formulations, in an open, two‐period, randomized, crossover protocol. The 90% confidence interval of the individual ratios (test formulation/reference formulation) for Cmax (peak plasma concentration), AUC0–96 and AUC0–inf (area under the plasma concentration versus time curve from time zero to 96 h and to infinity, respectively) were within the range 80–125%, which supports the conclusion that the test formulation is bioequivalent to the reference formulation regarding the rate and extent of bromazepam absorption. Copyright © 2004 John Wiley & Sons, Ltd.
Structural characterization of 5,6‐dichlorotetradecanoic acid, an isolated metabolite of 9,10‐dichlorooctadecanoic acid, by studying picolinyl esters, pyrrolidides and methyl esters with electron ionization mass spectrometry
Authors: Åkesson‐Nilsson Gunilla , Wesén Clas 
Published: November 2004

AbstractA method is presented for identification of positional isomers of dichlorinated fatty acids, based on derivatization to picolinyl esters prior to gas chromatographic/mass spectrometric analysis in the electron ionization mode. The mass spectra of the picolinyl esters showed structure‐specific fragmentation patterns. By using the picolinyl ester, 5,6‐dichlorotetradecanoic acid was identified as a metabolite from a cell‐culture medium obtained by culturing human cell lines in media supplemented with threo‐9,10‐dichlorooctadecanoic acid. This indicates that dichlorinated fatty acids are degraded by β‐oxidation. It is also possible to locate tentatively the position of chlorine atoms in 5,6‐dichlorotetradecanoic acid as its methyl ester or pyrrolidide. Copyright © 2004 John Wiley & Sons, Ltd.
Charge permutation reactions in tandem mass spectrometry
Authors: He Min , McLuckey Scott A. 
Published: November 2004

AbstractCentral to the tandem mass spectrometry experiment is the process that gives rise to product ions, i.e. the reaction intermediate to stages of mass analysis. Changes in mass or charge of the parent ion (or both) are generally readily detected by all forms of tandem mass spectrometry. Charge changing, or charge permutation, reactions have a long history in mass spectrometry. However, with the advent of new ionization methods, such as electrospray ionization, and the expansion of tandem mass spectrometry instrumentation to include ion trapping instruments, the past decade has seen a major increase in the types of charge permutation reactions that can be studied. Most charge permutation reactions involve electrons or protons as the charge mediating agents. This report, therefore, provides an overview of charge permutation reactions involving protons or electrons. Particular emphasis is placed on processes that involve interactions of precursor ions with gaseous neutral species, electrons or oppositely charged ions. Charge permutation reactions involving electron gain/loss are described first according to a rough order of the energy required for the reaction beginning with the most endoergic reactions and ending with the most exoergic reactions. An analogous approach is then taken with charge permutation reactions involving proton gain/loss. Important charge permutation reactions discussed herein, among others, include those referred to as charge inversion, charge stripping, electron capture dissociation, collision‐induced ionization and charge separation. These reaction types, and others described herein, are the subjects of active research and are also finding use in many current areas of application. Copyright © 2004 John Wiley & Sons, Ltd.
Chiral recognition in solution and the gas phase. Experimental and theoretical studies of aromatic D‐ and L‐amino acid–Cu(II)–chiragen complexes Jennifer L. Seymour František Tureček Andrei V. Malkov Pavel Kočovský Journal of Mass Spectrometry 2004; 39: 1044–1052
Authors: Seymour Jennifer L. , Tureček František , Malkov Andrei V. , Kočovský Pavel 
Published: November 2004

AbstractThe original article to which this Erratum refers was published in Journal of Mass Spectrometry 2004; 39: 1044–1052.
Transformational leadership and organizational commitment: mediating role of psychological empowerment and moderating role of structural distance
Authors: Avolio Bruce J. , Zhu Weichun , Koh William , Bhatia Puja 
Published: November 2004

AbstractUsing a sample of 520 staff nurses employed by a large public hospital in Singapore, we examined whether psychological empowerment mediated the effects of transformational leadership on followers' organizational commitment. We also examined how structural distance (direct and indirect leadership) between leaders and followers moderated the relationship between transformational leadership and organizational commitment. Results from HLM analyses showed that psychological empowerment mediated the relationship between transformational leadership and organizational commitment. Similarly, structural distance between the leader and follower moderated the relationship between transformational leadership and organizational commitment. Implications for research and practice of our findings are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
The proficiency trap: how to balance enriched job designs and the team's need for support
Authors: Drach‐Zahavy Anat 
Published: November 2004

AbstractThe present study seeks to enlighten our understanding of ways to promote the performance of teams of professionals. Considering that job enrichment practices might block support for a team, and hence its performance, the study examined the moderating effects of cultural factors, namely individualism–collectivism and power distance, and the team leader's practices as a source of support in the job enrichment–team support relationship. Further, the study examined the mediating role of team support in improving the performance of professional teams. Results from 56 healthcare teams from different hospitals indicated that attempts to promote professionals' performance should consider at a minimum how to balance job enrichment practices and the team's need for support. The findings suggest that this balance could be achieved by emphasizing the support provided by the leader, and by strengthening the cultural values of low power distance and collectivism in the team. Copyright © 2004 John Wiley & Sons, Ltd.
Modeling negative affectivity and job stress: a contingency‐based approach
Authors: Barsky Adam , Thoresen Carl J. , Warren Christopher R. , Kaplan Seth A. 
Published: November 2004

AbstractUnderstanding the role of negative affectivity (NA) in relations between job stressors and resultant strains has been a major source of research interest in the organizational literature for almost two decades. In this study, we propose a contingency approach, whereby the role of NA depends on the nature of the strain construct under investigation. Specifically, we predicted that perceived job stressors would fully mediate the relationship between NA and turnover intentions, while job stressors would only partially mediate the relationship between NA and job and life satisfaction, and job stressors would be unrelated to depression once NA was taken into account. The relative fit of these four models is tested utilizing data from two divergent samples (sales representatives and managers) employing both self‐ and informant reports of strain measures where feasible. Hypotheses regarding the specified nature of the NA → stressor → strain relationship generally were supported and replicated across samples. In addition, an alternate model specifying that NA moderates the relationship between stressors and strains was not supported for any strain variable. Copyright © 2004 John Wiley & Sons, Ltd.
Planning behavior and perceived control of time at work
Authors: Claessens Brigitte J. C. , Van Eerde Wendelien , Rutte Christel G. , Roe Robert A. 
Published: November 2004

AbstractThis study investigated two mediation models of time management. The first model consisted of parts of Macan's (1994) model. The second model combined this model with Karasek's (1998) Job Demand–Control model. Two sets of self‐report questionnaires were collected and were analyzed using structural equation modeling. The first model, in which perceived control of time was hypothesized to fully mediate the relation between planning behavior and work strain, job satisfaction, and job performance, was found to be less adequate than the second model, which added workload and job autonomy as independent variables. Results also indicated that partial, rather than full, mediation of perceived control of time fitted the data best. The study demonstrated the importance of studying both planning behavior and job characteristics, which was not part of past research. Copyright © 2004 John Wiley & Sons, Ltd.