bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of activation barriers for the diffusion of sodium through CIGS thin‐film solar cells
Authors: Zellner M. B. , Birkmire R. W. , Eser E. , Shafarman W. N. , Chen J. G. 
Published: December 2003

AbstractWe have determined the activation energies of sodium diffusion from the soda‐lime glass substrate through the Mo back‐contact layer, as well as through copper indium gallium diselenide (CIGS) deposited on the Mo back‐contact layer of CIGS thin‐film solar cells. The activation energies were determined by X‐ray photoelectron spectroscopy (XPS) to measure surface sodium concentrations before and after thermally induced diffusion. The activation energies were found to be similar for the diffusion of Na through the Mo/glass and CIGS/Mo/glass thin films, approximately 8·6 and 9·6 kcal/mol, respectively. Furthermore, the sodium diffusion was found to occur by annealing in an environment of 1·0×10−5 Torr of air, oxygen, or water vapor, but not in vacuum of less than 1×10−8 Torr. In addition, the diffusion of Na was found to occur faster in the presence of oxygen than in water under identical annealing conditions. Copyright © 2003 John Wiley & Sons, Ltd.
Improved performance in ZnO/CdS/CuGaSe2 thin‐film solar cells
Authors: Young David L. , Keane James , Duda Anna , AbuShama Jehad A. M. , Perkins Craig L. , Romero Manuel , Noufi Rommel 
Published: December 2003

AbstractWe report the growth and characterization of improved efficiency wide‐bandgap ZnO/CdS/CuGaSe2 thin‐film solar cells. The CuGaSe2 absorber thickness was intentionally decreased to better match depletion widths indicated by drive‐level capacitance profiling data. A total‐area efficiency of 9·5% was achieved with a fill factor of 70·8% and a Voc of 910 mV. Published in 2003 by John Wiley & Sons, Ltd.
Competence, persistence, and success: The positive psychology of behavioral skill instruction
Authors: Martens Brian K. , Witt Joseph C. 
Published: December 2003

AbstractEarly school failure is a critical factor in the development of peer rejection and antisocial behavior in children. This paper describes three sets of instructional strategies that have been shown to promote high levels of academic competence by arranging frequent opportunities for correct skill practice: (a) teaching children at their instructional level and monitoring progress, (b) teaching children differently as their skills improve, and (c) rewarding success and setting goals. Research is reviewed showing that practicing skills to high levels of fluency leads to retention and endurance, the emergence of new forms of a skill, and creative problem solving. The motivation of children to complete academic tasks through the strategic use of reinforcement is discussed, as are the implications of these strategies for encouraging children to be persistent, self‐motivated, life‐long learners. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 19–30, 2004.
Life satisfaction in children and youth: Empirical foundations and implications for school psychologists
Authors: Huebner E. Scott , Suldo Shannon M. , Smith Laura C. , McKnight Caroline G. 
Published: December 2003

AbstractA central component of positive psychology is subjective well‐being (SWB). One facet of SWB receiving increased research attention is children's perceived quality of life (PQOL). Existing research related to child and youth PQOL is reviewed, followed by a discussion of the implications of the research for school psychology practice. Research with children and adolescents reveals that PQOL has a wide ranging nomological network including personality, environmental, and activity variables. Furthermore, PQOL appears to mediate relationships between the environmental experiences of youth and problem behavior. Implications are discussed within the context of calls for greater attention by school psychologists to prevention, non‐traditional assessment, direct service, consultation with teachers and parents, diversity issues, and the science‐practice connection. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 81–93, 2004.
Enhancing subjective well‐being in individuals with asthma
Authors: Bray Melissa A. , Kehle Thomas J. , Peck Heather L. , Theodore Lea A. , Zhou Zheng 
Published: December 2003

AbstractAsthma, a chronic respiratory disease, is caused by a complex interaction between genetic and environmental variables. The intent of this article is to propose a theory that provides an explanation for the reduction of emotionally triggered asthma through treatments derived from positive psychology. The basic tenet of the theory is that physical health issues, such as asthma, can be promoted through systematic interventions that are designed to enhance the individual's sense of independence, intimacies or friendships, and/or feelings of competence. This theoretical approach is based largely on Bertrand Russell's definition of happiness and is consistent with positive psychology in that it focuses on variables that promote subjective well‐being, or a satisfying daily life. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 95–100, 2004.
Positive psychology in the prevention of eating disorders
Authors: Steck Erin L. , Abrams Laura M. , Phelps LeAdelle 
Published: December 2003

AbstractTraditionally the identification of, and treatment for, eating disorders has been based on developmental psychopathology theory and research, thereby emphasizing risk factors and the elimination of maladaptive behaviors. This article seeks to reconceptualize the prevention of, and protective factors for, eating disordered behavior from the positive psychology framework proposed by Seligman and Csikszentmihalyi. This philosophy posits that psychology should strive to identify characteristics relating to positive subjective experiences, constructive individual traits, and affirmative institutions for the purpose of emphasizing and enhancing these strengths. To this end, we present recent literature on promoting protective factors with respect to these variables in the prevention of eating disorders. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 111–117, 2004.
Integrating positive psychology into schools: Implications for practice
Authors: Terjesen Mark D. , Jacofsky Matthew , Froh Jeffrey , DiGiuseppe Raymond 
Published: December 2003

AbstractTraditional approaches for working with children and families in the schools focus on problems and disturbance. The concept of positive psychology as a way to change this focus is offered through exploration of its integration within school psychology. Specifically, the application of positive psychology can form the basis of preventive practices within the school setting. Examples of this application are provided within common roles of the school psychologist (consultation, direct work, educational assessment and planning). © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 163–172, 2004.
Activation of the Raf‐1/MEK/Erk kinase pathway by a novel Cdc25 inhibitor in human prostate cancer cells
Authors: Nemoto Kaoru , Vogt Andreas , Oguri Tetsuya , Lazo John S. 
Published: December 2003

AbstractBACKGROUNDThe serine/threonine kinase Raf‐1 is a major regulator of the mitogen activated protein kinase (MAPK) pathway, which has been associated with the progression of prostate cancer to the more advanced and androgen‐independent disease. Cdc25A phosphatase has been implicated in the regulation of Raf‐1 and the MAPK pathway.METHODSWe used a novel and potent Cdc25A inhibitor, 2,3‐bis‐[2‐hydroxyethylsulfonyl]‐[1,4] naphthoquinone (NSC 95397), and its congener (2‐mercaptoethanol)‐3‐methyl‐1, 4‐naphthoquinone (NSC 672121) to study the role of Cdc25A on the MAPK pathway in human prostate cancer cells.RESULTSWe found Raf‐1 physically interacted with Cdc25A in PC‐3 and LNCap cells and inhibitors of Cdc25A induced both extracellular signal‐regulated kinase (Erk) activation and Raf‐1 tyrosine phosphorylation. NSC 95397 attenuated Cdc25A and Raf‐1 interactions due to accelerated degradation of Cdc25A, which was mediated by proteasome degradation. The MAPK kinase (MEK) inhibitor U0126 completely inhibited Erk activation by NSC 95397 and NSC 672121.CONCLUSIONSThese results indicate Cdc25A phosphatase regulates Raf‐1/MEK/Erk kinase activation in human prostate cancer cells. © 2003 Wiley‐Liss, Inc.
De novo sequencing of novel neuropeptides directly from Ascaris suum tissue using matrix‐assisted laser desorption/ionization time‐of‐flight/time‐of‐flight
Authors: Yew Joanne Y. , Dikler Sergei , Stretton Antony O. 
Published: December 2003

AbstractDirect analysis of tissue by matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) allows for the rapid profiling of biological molecules with minimal loss of sample or degradation and reduced likelihood of chemical modification. However, there are still considerable challenges to overcome due to the complexity of tissue and the low quantity of endogenous peptide in a single cell. These problems are exacerbated in the nematode Ascaris suum because of the small size of individual neurons and the paucity of peptide per cell. In an effort to address these difficulties, the recently developed matrix‐assisted laser desorption/ionization time‐of‐flight/time‐of‐flight (MALDI‐TOF/TOF) technology was used in combination with an on‐target derivatization in order to sequence novel neuropeptides directly from Ascaris nervous tissue. Direct MALDI‐TOF/TOF analysis of Ascaris tissue provided the complete amino acid sequences for a previously characterized neuropeptide as well as for three novel peptides with homologues found in other nematodes. These results demonstrate a method for the rapid characterization of sub‐femtomolar amounts of peptide directly from tissue using MALDI‐TOF/TOF. Copyright © 2003 John Wiley & Sons, Ltd.
A strategy for metabolite identification using triple‐quadrupole mass spectrometry with enhanced resolution and accurate mass capability
Authors: Jemal Mohammed , Ouyang Zheng , Zhao Weiping , Zhu Mingshe , Wu Wells W. 
Published: December 2003

AbstractUsing a single platform of a triple‐quadrupole mass spectrometer equipped with enhanced resolution and accurate mass capabilities, a strategy for metabolite identification of a drug in a biological matrix has been demonstrated. The strategy is based on first screening for metabolites via neutral loss and precursor ion scan schemes, devised as the result of the product ion spectrum of a matrix‐free standard of the drug. The accurate masses of the precursor ions identified via the two scan schemes plus the precursor ions of structurally likely metabolites are then determined by enhanced resolution, accurate mass (AM) selected ion monitoring (SIM). The identities of the metabolites are further established by determining the accurate masses of the product ions via enhanced resolution AM selected reaction monitoring (SRM). The feasibility of the strategy was demonstrated using a liver microsome incubation sample of nefazodone, an antidepressant drug. The neutral loss and precursor ion screening runs were able to identify most of the metabolites of nefazodone. The subsequent SIM and SRM experiments gave mass accuracy of better than ±0.003 u for the masses of the precursor and product ions of nefazodone and all the metabolites. The ability to perform metabolite screening by using the scan features followed by accurate mass determinations on the same instrument is an attractive feature of using a triple‐quadrupole mass spectrometer with enhanced resolution and accurate mass capability. Copyright © 2003 John Wiley & Sons, Ltd.
Mass spectrometric studies of cisplatin‐induced changes of hemoglobin
Authors: Mandal Rupasri , Kalke Robyn , Li Xing‐Fang 
Published: December 2003

AbstractThis study reports on structural changes of hemoglobin (Hb) that were induced by cisplatin binding. Two techniques, nanoelectrospray quadrupole time‐of‐flight mass spectrometry (nanoES‐MS) and high‐performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC/ICPMS), were developed to facilitate this study. Nanospray MS analyses of cisplatin and Hb reaction mixtures demonstrated that the ion at m/z 616.5, the heme group, increased with an increase of cisplatin concentration, indicating the loss of heme groups from the intact protein. This conclusion was also supported by the increase of cisplatin‐α or ‐β complex formation. The change of the Hb‐bound Fe was further investigated by monitoring Fe signals using size‐exclusion HPLC/ICPMS. After incubation with cisplatin at clinically relevant concentrations, under physiological conditions, the amount of Fe bound to Hb was reduced while formation of cisplatin–Hb complexes increased. Flow‐injection ICPMS analysis of the Fe contents in the low molecular weight fraction (<3000 Da) of the reaction mixtures after size fractionation further demonstrated a corresponding increase of Fe with the increase of cisplatin concentrations. HPLC/ICPMS detected three Hb–cisplatin complexes, one of which eluted at the same retention time as Hb while the other two complexes eluted later than Hb. With clinically relevant concentrations of cisplatin (0.05–1.0 μM) and 10 μM of Hb, the concentrations of the Hb–cisplatin complexes were determined in the range 0.1–64 nM. These results, obtained from nanoES‐MS, HPLC/ICPMS, and FIA‐ICPMS, demonstrate that cisplatin binding to Hb resulted in the dissociation of the heme group from the intact protein. Copyright © 2003 John Wiley & Sons, Ltd.
Kinetics of gas‐phase hydrogen/deuterium exchange and gas‐phase structure of protonated phenylalanine, proline, tyrosine and tryptophan
Authors: Rožman Marko , Kazazić Saša , Klasinc Leo , Srzić Dunja 
Published: December 2003

AbstractSite‐specific rate constants for the gas‐phase hydrogen/deuterium (H/D) exchange of four, three, five and five hydrogen atoms in protonated phenylalanine (Phe), proline (Pro), tyrosine (Tyr) and tryptophan (Trp), respectively, were determined from matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI‐FTICRMS) experiments with D2O, D2S, and CH3OD as deuterating agents. No H/D exchange was observed with D2S. For exchange with both CD3OD and D2O, which is about ten times slower in the latter, results indicate for all compounds protonation of the α‐amino group in agreement with theoretical results. Also, with both reagents, all compounds exchange at the COOH site more than ten times faster than at the protonation site, with OH and NH sites of Tyr and Trp, respectively, exchanging slowest. The observation of H/D exchange despite the high differences in proton affinities between the amino acids and deuterating agent exceeding 200 kJ mol−1 is in agreement with lowering of the barrier for proton transfer through hydrogen bonding proposed by Lebrilla and coworkers. Copyright © 2003 John Wiley & Sons, Ltd.
Automated discrimination of polymerase chain reaction products with closely related sequences by software‐based detection of characteristic peaks in product ion spectra
Authors: Muhammad Warees T. , Tabb David L. , Fox Karen F. , Fox Alvin 
Published: December 2003

AbstractA computer‐based method is described for automated detection of peaks in product ion spectra that allows discrimination of structurally related polymerase chain reaction (PCR) products. PCR products of K‐ras mutants having single nucleotide substitutions and isomeric sequence changes in positions 1 and 2 of codon 12 (e.g. TGT and GTT) were used as a model system. SpecDiff, a tool for differentiating pairs of mass spectra by identifying peaks that either differ in relative intensity between spectra or only appear in one of a pair of spectra, was created to help automate detection. This program was demonstrated to have great utility in detection of mutations and could also be useful as a general tool for differentiating other molecules of closely related structure. Copyright © 2003 John Wiley & Sons, Ltd.
Development of a liquid chromatographic time‐of‐flight mass spectrometric method for the determination of unlabelled and deuterium‐labelled α‐tocopherol in blood components
Authors: Hall Wendy L. , Jeanes Yvonne M. , Pugh Jonathan , Lodge John K. 
Published: December 2003

AbstractA method is described for the analysis of deuterated and undeuterated α‐tocopherol in blood components using liquid chromatography coupled to an orthogonal acceleration time‐of‐flight (TOF) mass spectrometer. Optimal ionisation conditions for undeuterated (d0) and tri‐ and hexadeuterated (d3 or d6) α‐tocopherol standards were found with negative ion mode electrospray ionisation. Each species produced an isotopically resolved single ion of exact mass. Calibration curves of pure standards were linear in the range tested (0–1.5 μM, 0–15 pmol injected). For quantification of d0 and d6 in blood components following a standard solvent extraction, a stable‐isotope‐labelled internal standard (d3‐α‐tocopherol) was employed. To counter matrix ion suppression effects, standard response curves were generated following identical solvent extraction procedures to those of the samples. Within‐day and between‐day precision were determined for quantification of d0‐ and d6‐labelled α‐tocopherol in each blood component and both averaged 3–10%. Accuracy was assessed by comparison with a standard high‐performance liquid chromatography (HPLC) method, achieving good correlation (r2 = 0.94), and by spiking with known concentrations of α‐tocopherol (98% accuracy). Limits of detection and quantification were determined to be 5 and 50 fmol injected, respectively. The assay was used to measure the appearance and disappearance of deuterium‐labelled α‐tocopherol in human blood components following deuterium‐labelled (d6) RRR‐α‐tocopheryl acetate ingestion. The new LC/TOFMS method was found to be sensitive, required small sample volumes, was reproducible and robust, and was capable of high throughput when large numbers of samples were generated. Copyright © 2003 John Wiley & Sons, Ltd.
High‐precision measurements of 17O/16O and 18O/16O of O2 and O2/Ar ratio in air
Authors: Barkan Eugeni , Luz Boaz 
Published: December 2003

AbstractA method for high‐precision and high‐accuracy mass spectometric measurements of the ratios among the three oxygen isotopes, and of the O2/Ar ratio, is presented. It involves separation of the O2‐Ar mixture from air and includes a fully automated system that ensures highly reliable sample processing. Repeated measurements of atmospheric oxygen yield the repeatability (±SE × t, standard error of the mean (n = 12) multiplied by Student's t‐factor for a 95% confidence limit) of 0.004, 0.003 and 0.2‰ for δ18O, δ17O and δO2/Ar, respectively. Copyright © 2003 John Wiley & Sons, Ltd.
A comparison of accurate mass techniques for the structural elucidation of fluconazole
Authors: Thompson Christine M. , Richards Donald S. , Fancy Sally‐Ann , Perkins George L. , Pullen Frank S. , Thom Catriona 
Published: December 2003

AbstractMass spectrometry plays a major role in the structural elucidation and characterisation of drug candidates and related substances. Accurate mass data allow the mathematical prediction of molecular formula of both precursor and fragment ions. In this paper, a comparison of the accurate mass data obtained for the fragmentation of fluconazole, an antifungal drug, by three different methods is made: electron ionisation (EI) using a magnetic sector instrument; electrospray ionisation (ES) using a Fourier transform ion cyclotron mass spectrometer (FTICRMS); and ES using a quadrupole—time‐of‐flight mass spectrometer (Q‐ToF). It is clear from the data obtained that mass accuracy is not simply a function of instrument resolution. The subtle differences observed between collisionally activated dissociation (CAD) and sustained off‐resonance collisionally activated dissociation (SORI‐CAD) spectra are explained as a consequence of the excitation process. The advantages and disadvantages of the three techniques are discussed within the context of structural elucidation. Copyright © 2003 John Wiley & Sons, Ltd.
Stable‐isotope dilution analysis of galactose metabolites in human erythrocytes
Authors: Schadewaldt Peter , Kamalanathan Loganathan , Hammen Hans‐Werner , Wendel Udo 
Published: December 2003

AbstractAn established gas chromatography/mass spectrometry (GC/MS) method, devised for stable‐isotope dilution analysis of plasma galactose, was developed to allow determination of erythrocyte (red blood cell, RBC) concentrations of galactose‐1‐phosphate and other primary metabolites relevant in galactosaemia. Galactose‐1‐phosphate was enzymatically converted to galactose, and the aldononitrile pentaacetate derivative was separated by gas chromatography and determined by mass spectrometry using chemical ionisation and selected ion monitoring of the [MH–60]+ ion. U‐13C‐Labelled standard was used for quantification. Comparative measurements were conducted using established fluorimetric and radiometric enzymatic methods. The GC/MS analysis for galactose‐1‐phosphate was linear (range examined 0–600 μmol/LRBC, packed cells), of acceptable repeatability at low and high concentrations (within and between run CVs <15%), with a limit of quantification of 0.01 μmol/LRBC. With samples from patients with classical galactosaemia there was a linear correlation with conventional enzymatic assays (r2 > 0.927). In erythrocytes from post‐absorptive patients under treatment, Q188R‐heterozygous parents, and healthy subjects, galactose‐1‐phosphate concentrations (mean ± SD) were found to be 142 ± 38 (n = 41), 1.4 ± 0.2 (n = 8), and 1.9 ± 0.5 (n = 33) μmol/LRBC, respectively. In comparison, free galactose concentrations were 3.8 ± 1.7, 0.49 ± 0.19, and 0.43 ± 0.20 mol/LRBC, respectively. The procedure allowed simultaneous galactitol analysis and proved to be useful to trace incorporation of 13C‐label into erythrocyte galactose metabolites in a D‐[1‐13C]galactose in vivo turnover study. Copyright © 2003 John Wiley & Sons, Ltd.
Acid‐induced denaturation of cellular retinol‐binding proteins types I and II studied by electrospray mass spectrometry
Authors: Careri Maria , Elviri Lisa , Zagnoni Ingrid , Cavazzini Davide , Rossi Gian Luigi 
Published: December 2003

AbstractThe acid‐induced denaturation of cellular retinol‐binding proteins types I and II (CRBP I and II), in the presence and in the absence of the ligand, was studied by electrospray ionization mass spectrometry (ESI‐MS) in the pH range 6.9–2.4. To avoid artifacts generated by the ESI process, suitable interface parameters were selected. Different charge‐state distributions were observed in the ESI‐MS spectra, reflecting the pH‐dependent equilibria among protein conformations in solution. In the absence of retinol, CRBP II appeared to be more resistant than CRBP I to acid denaturation. The bound ligand stabilized both carriers, with a markedly higher effect on CRBP I. Retinol release from the ligand‐bound carriers and protein denaturation occurred concomitantly. This finding suggests that the lowering of pH, reported to occur in proximity to a biomembrane, might contribute to the conformational transitions required to promote dissociation of the otherwise very stable retinal–carrier complexes and thus permit targeted delivery of vitamin A to the enzymes involved in its metabolism. Copyright © 2003 John Wiley & Sons, Ltd.