bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of the disulfides of bio‐thiols by electrospray ionization and triple‐quadrupole tandem mass spectrometry
Authors: Rubino Federico Maria , Verduci Cinzia , Giampiccolo Rosario , Pulvirenti Salvatore , Brambilla Gabri , Colombi Antonio 
Published: December 2004

AbstractGlutathione and other intracellular low molecular mass thiols act both as the major endogenous antioxidant and redox buffer system and, as recently highlighted, as an important regulator of cellular homeostasis. Such cellular functions are mediated by protein thiolation, a newly recognized post‐translational modification which involves the formation of mixed disulfides between GSH and key disulfide‐linked Cys residues in the native protein structure. It is also well known that thiol‐seeking heavy metals, such as mercury, cadmium and lead, may interfere in this regulatory system, thus disrupting the cellular functioning. To identify such mixed disulfides in order to investigate their biological role, 15 homo‐ and heterodimeric disulfides were prepared by air oxidation of binary mixtures containing cysteine, homocysteine, penicillamine, N‐acetylcysteine, N‐acetylpenicillamine and glutathione and their protonated molecules were characterized by mass spectrometry. Collisionally activated unimolecular decomposition of protonated homo‐ and heterodimeric disulfides generated by electrospray ionization gives rise to fission of the disulfide system both between the two sulfur atoms and across the CS bonds, to yield structurally specific fragments which allow one to define the structure of the compounds and to discriminate between isomeric compounds. Fission between the sulfur atoms yields a pair of RS+ ions and, in some cases, also the complementary fragments corresponding to the protonated amino acids. Fission across the CS bonds mainly occurs in the disulfides of N‐acetylcysteine and N‐acetylpenicillamine and gives rise to non‐S‐containing fragments formally similar to those obtained from some mercapturic acids. The complementary fragments, formally connected as RSS+ ions are also observed. Fragmentation of glutathione disulfides mainly shows the characteristic loss of the terminal γ‐linked glutamic acid and little, if any, fragmentation of the disulfide system. Copyright © 2004 John Wiley & Sons, Ltd.
Using mass spectrometry to probe the subtle differences in conformations of several cytochromes c in aqueous and methanol solutions
Authors: Wang Yao‐Fong , Ho May‐Yeh , Ho Yen‐Peng 
Published: December 2004

AbstractWe have detected, using electrospray mass spectrometry, minor changes in the H/D exchange rates in various solvents for cytochromes c obtained from five different species. We compared the exchange rates exhibited by these proteins by mixing horse cytochrome c with each of the other four species and monitoring their exchanges simultaneously by mass spectrometry. The use of horse cytochrome c as a reference allowed us to make very accurate comparisons of the small differences in hydrogen exchange rates among the various species. The exchange experiments were performed in water and methanol at several concentrations in an effort to determine whether the cytochromes c of these five species have different conformations in specific solvents, which would cause their exchange rates to differ. Therefore, monitoring the level of exchange as a function of time in both water and water–methanol mixtures is a method for detecting subtle structural changes of proteins in their native or unfolded intermediate states. Copyright © 2004 John Wiley & Sons, Ltd.
Regional phospholipid analysis of porcine lens membranes by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Estrada Rosendo , Yappert M. Cecilia 
Published: December 2004

AbstractThe applicability of matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) to the qualitative and quantitative analysis of most mammalian phospholipid (PL) classes was demonstrated in a crude extract of porcine lens membranes. When 2,5‐dihydroxybenzoic acid (DHB) was used as the matrix, positive‐ion spectra allowed the accurate quantification of phosphatidylcholines (PCs) and sphingomyelins (SMs). Other PLs such as phosphatidylethanolamines (PEs), phosphatidylethanolamine plasmalogens (PEps), phosphatidylethanolamine ethers (PEes) and phosphatidylserines (PSs), could also be detected, but their lower ionization efficiency led to negative errors in their quantification. Despite this limitation, it was possible to determine relative changes among PLs extracted from cortical and nuclear regions. Negative‐ion spectra were acquired with the use of p‐nitroaniline (PNA) as the matrix. Because neither PCs nor SMs produce negative ions, other PL classes can be analyzed selectively. The absolute quantification of the various PL classes detectable in negative‐ion spectra was also affected by differences in ionization efficiencies. However, the trends in compositional changes between cortical and nuclear‐fiber PLs were in agreement with those obtained by 31P NMR spectroscopy. MALDI‐TOFMS also offers the possibility of studying variations in the acyl‐chain distribution of the various species comprising each PL class. For porcine lenses, PCs, PEs and phosphatidylinositols (PIs) exhibited the greatest depletions in going from cortical to nuclear membranes. Among their individual species, those with two or more sites of unsaturation suffered the most significant reduction. Copyright © 2004 John Wiley & Sons, Ltd.
Different behavior of dextrans in positive‐ion and negative‐ion mass spectrometry
Authors: Čmelík Richard , Štikarovská Markéta , Chmelík Josef 
Published: December 2004

AbstractA mass spectrometric (MS) comparative study of dextran samples using two different ionization techniques (matrix‐assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI)) in both positive‐ and negative‐ion modes is reported. The experiments were carried out with two polydisperse dextrans (1000 and 8800 Da) and isomaltotriose. In the positive‐ion mode, the expected alkali metal ion adducts of dextrans were observed in both techniques. In contrast, the expected preferential formation of deprotonated molecules [M − H]− was not confirmed in negative mode MALDI time‐of‐flight (TOF) MS, where the series of ions [Mx− H +42]− or [Mx+1− H − 120]−, coming either from some addition or fragmentation, were observed. In both ionization techniques, these ions formed the main distributions of dextrans in the negative‐ion mode. It seems that the negative molecular ions formed from the α1 → 6 linkage of polyglucose oligomers easily decompose, and the product ions [M − H − 120]− markedly dominate. The fragmentation experiments and especially the investigation of the fundamental role of the nozzle–skimmer potential in ESI‐MS supported our explanation of the observed behavior because its higher values caused higher fragmentation. The experiments with isomaltotriose excluded any addition of 42 Da during the MS procedures, which is not distinguishable from the loss of 120 Da in the case of polydisperse dextrans. MALDI‐TOFMS was found to be more sensitive for the detection of higher oligosaccharides and ESI‐MS more useful for structural studies. Copyright © 2004 John Wiley & Sons, Ltd.
Skill of a superensemble forecast over equatorial Southeast Asia
Authors: Mahmud Mastura 
Published: December 2004

AbstractThe performance of the multianalysis–multimodel superensemble weather forecast and its comparison with several other operational prediction models is investigated in this study for the Southeast Asian region. The superensemble technique has been proven to exhibit exceptional skills compared with individual or even ensemble average forecasts for parameters such as precipitation, motion and mass fields. Precipitation forecasts from the superensemble technique for the year of 2001 from this study show that its skill scores are better than the other global operational models employed. Its precipitation root‐mean‐square errors (RMSEs) are consistently lower than the other member models for the annual period examined. The equitable threat score, which indicates the association of the common rainfall threshold distribution between the forecast and observed best rainfall analysis from the Tropical Rainfall Measurement Mission and Special Sensor Microwave Imager dataset, is slightly underpredicted for light rain thresholds, but it still outperforms the other individual members or even the ensemble mean forecasts. Correlation analysis of the superensemble forecast against the observed is far higher than either the ensemble mean or the individual forecast member models and is maintained for up to 3‐day forecasts.The motion field comparisons also exhibit that the superensemble forecasts are closer to the observed data than the other member models due to its low systematic errors at the 850 hPa pressure level. Both the precipitation and wind field analyses have shown that the Florida State University multianalysis–multimodel superensemble forecast provides the lowest RMSE, the highest correlation against the best‐observed data and lowest systematic errors compared with the other participating operational models. These forecasts have the potential to provide better daily weather predictions over the Southeast Asian region, particularly during the early northeast monsoon that often causes heavy rainfall in the equatorial part of the Southeast Asian region. Copyright © 2004 Royal Meteorological Society
Problematics in management theory and practice
Authors: Franklin Peter 
Published: December 2004

Abstract

This paper is concerned with the methodological and epistemological foundations of management theory. It develops the argument that management theory is essentially unreliable and in terms of a modernist or postmodernist epistemology, unable to offer any insights or understandings beyond those argued from the study of the specific instances of a specific case.
This dismal argument casts doubt on the philosophical validity of much formal management theory, and has serious implications about the use and application of theory by managers. Similarly, the argument can be used to cast doubt on the ethical stance of gurus and consultants that have allowed readers, users and clients to believe mistakenly that they have bought prescriptions, theories and models which have validity and wide applicability beyond the instances of a specific case or a specific industry.
Within the context of the philosophy of science, such scepticism about formal theory should be regarded as normal and healthy (Kuhn, 1970). Within the field of management, scepticism about formal theory offers managers the opportunity to seize the empty creative space ignored by the generalizing modernist solutions and thereby create, share and laud theory grounded in their own management practice. In this context, the impossibility of management theory based on the modernist paradigm should be seen as liberating rather than constraining.
The abandonment of management theories spawned by modernism and the false claims of science provides managers with an opportunity to escape the dictums of the gurus and the tired models entombed within the hard covers of hundreds of strategy textbooks. In brief, the end of modernism and the abandonment of the myth of a general theory of management offers managers a chance to rethink and repractise ways of understanding, choosing and creating different and hopefully more fulfilling futures.

Copyright © 2004 John Wiley & Sons, Ltd.
Attempts to more effectively target ethnic minority customers: the case of HSBC and its South Asian business unit in the UK
Authors: Chaudhry Shiv , Crick Dave 
Published: December 2004

Abstract

With some regions of the UK containing areas where the ethnic minority population has grown to become the ethnic majority, both personal and business banking needs of these communities provide areas of potential growth for financial institutions. Previous research has indicated that certain organizations do not understand particular cultural practices of customers within ethnic communities and have ineffectively targeted them.
This paper provides an insight into how a major bank has addressed the needs of particular ethnic communities. It reports on interview data with the Head of HSBC's South Asian Business Unit. The findings provide a contribution to the body of knowledge associated with the interface between subculture and financial institutions' marketing practices.

Copyright © 2004 John Wiley & Sons, Ltd.
Disparities in the recording of Parkinson's disease on death certificates
Authors: Pressley Joyce C. , Tang Ming‐Xin , Marder Karen , Cote Lucien J. , Mayeux Richard 
Published: December 2004

AbstractAlthough little is known regarding potential socioeconomic or racial bias in the recording of Parkinson's disease (PD) on death certificates, studies of incidence, prevalence, and the etiology of PD frequently rely on this type of data. A national population‐based survey was linked to death certificate data to investigate the concordance of PD reported on death certificates for persons reporting PD during life. Logistic regression was used to identify independent factors associated with differential reporting of PD at death. Among decedents with PD reported during life, 54.8% had PD recorded on the death certificate. Nearly 70% of persons in higher income categories had PD recorded at death compared to 35.4% for those earning $10,000 or less. Age and gender adjusted odds of having PD recorded at death was 2.3 (1.1–3.9), for those with an annual income of $35,000 or more. Income differences remain significant in multivariable models after controlling for age, gender, race, census region, family size, rural residence, and number of chronic medical conditions. In conclusion, this study found socioeconomic bias in the reporting of PD at death. This bias is large enough to confound death certificate–based investigations of incidence, prevalence, and risk factors that differ across socioeconomic strata. © 2004 Movement Disorder Society
Levodopa‐dyskinesia incidence by age of Parkinson's disease onset
Authors: Kumar Neeraj , Van Gerpen Jay A. , Bower James H. , Ahlskog J. Eric 
Published: December 2004

AbstractWe assessed the 5‐year risk of levodopa‐induced dyskinesias by age of Parkinson's disease (PD) onset in a population‐based cohort. The medical records linkage system of the Rochester Epidemiology project was used to identify residents of Olmsted County, Minnesota, with incident PD for the period 1976 through 1990. In this population‐based study, the 5‐year dyskinesia incidence declined with age. With PD onset after 70 years of age, the incidence was 16%. With onset from 40 to 59 years of age, the incidence was higher at 50%. These incidence data may overestimate the functional importance, because patients with minimal or reversible dyskinesias were counted. © 2004 Movement Disorder Society
On the existence of incompressible current–vortex sheets: study of a linearized free boundary value problem
Authors: Trakhinin Yuri 
Published: December 2004

AbstractWe study the initial boundary value problem resulting from the linearization of the equations of ideal incompressible magnetohydrodynamics and the jump conditions on the hypersurface of tangential discontinuity (current–vortex sheet) about an unsteady piecewise smooth solution. Under some assumptions on the unperturbed flow, we prove an energy a priori estimate for the linearized problem. Since the so‐called loss of derivatives in the normal direction to the boundary takes place even for the constant coefficients linearized problem, for the variable coefficients problem and non‐planar current–vortex sheets the natural functional setting is provided by the anisotropic weighted Sobolev space W21,σ. The result of this paper is a necessary step to prove the local in time existence of solutions of the original non‐linear free boundary value problem. The uniqueness of the regular solution of this problem follows already from the a priori estimate we obtain for the linearized problem. Copyright © 2005 John Wiley & Sons, Ltd.
Assessing weak intramolecular donor–acceptor interactions using 1H117Sn J‐HMQC spectroscopy. Magnetic Resonance in Chemistry 2004; 42: 776–780
Authors: Biesemans Monique , Martins José C. , Jurkschat Klaus , Pieper Nicole , Seemeyer Stefan , Willem Rudolph 
Published: December 2004

AbstractThe original article to which this Corrigendum refers was published in Magnetic Resonance in Chemistry 2004; 42: 776–780
Psychometric properties and validation of the German‐language King's Health Questionnaire in women with stress urinary incontinence
Authors: Bjelic‐Radisic Vesna , Dorfer Martha , Tamussino Karl , Greimel Elfriede 
Published: December 2004

AbstractAimsThe purpose of this study was to evaluate the psychometric properties of and validate the German‐language version of the King's Health Questionnaire (KHQ) in women with stress urinary incontinence (SUI).MethodsA total of 145 women treated for stress incontinence with surgery or physiotherapy completed the the KHQ and the SF‐36 before and after treatment. Psychometric analyses of the quality of life (QoL) instruments determined the reliability (Cronbach's alpha), internal and external validity, and responsiveness of the KHQ subscales.ResultsThe KHQ showed good internal consistency, content validity, and criterion validity as measured by correlation with scores on the SF‐36. Cronbach's alpha coefficient ranged from 0.76 to 0.86, indicating a high internal consistency of the subscales. Concerning criterion validity, correlations between the KHQ subscales and the SF‐36 were low to moderate. The highest correlation was found between the general health perception subscales of both questionnaires.ConclusionsThe results indicate good psychometric properties for the German‐language KHQ. © 2004 Wiley‐Liss, Inc.
Equivalent localization element for crack band approach to mesh‐sensitivity in microplane model
Authors: Červenka Jan , Bažant Zdeněk P. , Wierer Martin 
Published: December 2004

AbstractThe paper presents in detail a novel method for finite element analysis of materials undergoing strain‐softening damage based on the crack band concept. The method allows applying complex material models, such as the microplane model for concrete or rock, in finite element calculations with variable finite element sizes not smaller than the localized crack band width (corresponding to the material characteristic length). The method uses special localization elements in which a zone of characteristic size, undergoing strain softening, is coupled with layers (called ‘springs’) which undergo elastic unloading and are normal to the principal stress directions. Because of the coupling of strain‐softening zone with elastic layers, the computations of the microplane model need to be iterated in each finite element in each load step, which increases the computer time. Insensitivity of the proposed method to mesh size is demonstrated by numerical examples. Simulation of various experimental results is shown to give good agreement. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and Crystal Structures of Two Cadmium Coordination Chain Polymers
Authors: He Xiang , Lu Can‐Zhong 
Published: December 2004

AbstractHydrothermal reactions of cadmium precursors with 2, 2′‐bipyridine, fumaric acid or NaN3 in basified aqueous solutions gave rise to two cadmium complexes [Cd(bipy)(fum)(H2O)]n (1), and [Cd(bipy)(μ1, 1‐N3)2]n (2) (fum = fumarate dianion), which were characterized by X‐ray crystallography. Complex [Cd(bipy)(fum)(H2O)]n (1) crystallizes in the orthorhombic system, space group Pbca, with a = 9.0488(8), b = 16.246(3), c = 19.810(4) Å, and Z = 8 while complex [Cd(bipy)(μ1, 1‐N3)2]n (2) in the monoclinic system, space group C2/c, with a = 12.378(3), b = 14.788(3), c = 6.6139(13) Å, β = 91.49(3)°, and Z = 4. The photoluminescence spectra for compounds 1 and 2 have also been studied.
Reaction of Hydroxyurea with Iron(III): Products and the Stoichiometry of the Redox Reaction
Authors: Kujundžić Nikola , Nigović Biljana , Sanković Krešimir 
Published: December 2004

AbstractProducts and reaction stoichiometry of the interaction between iron(III) and hydroxyurea (HU) in aqueous solutions were studied. Under condition of an excess of iron(III) over hydroxyurea, initially formed mono(hydroxyureato)iron(III) complex decomposed through redox processes, forming two moles of FeII, one mole of NH4+, one mole of CO2, and 0.5 mole of N2O per 1 mole of initially present HU. Hydroxyurea radical, H2N‐CO‐NHO?, was detected in the course of the reaction. The possible mechanism of the formation of the products is discussed and compared with that obtained for horseradish peroxidase mediated oxidation of hydroxyurea with hydrogen peroxide. The possibility of direct reaction of hydroxyurea with the iron center of protein R2 of the ribonucleotide reductase is proposed. The reaction examined may serve as a simple model for testing the suggested hydroxyurea like activity for chemical substances.
Synthese und Struktur hochfunktionalisierter 2, 3‐Dihydro‐1H‐1, 3, 2‐diazaborole
Authors: Weber Lothar , Rausch A. , Stammler H.‐G. , Neumann B. 
Published: December 2004

AbstractEine Reihe von 2, 3‐Dihydro‐1H‐1, 3, 2‐diazaborolen wurde auf verschiedenen Wegen hergestellt. 1, 3‐Di‐tert‐butyl‐2‐trimethylsilylmethyl‐1H‐1, 3, 2‐diazaborol (7), 2‐Isobutyl‐1, 3‐bis(1‐cyclohexylethyl)‐1H‐1, 3, 2‐diazaborol (8), 1, 3‐Bis(1‐cyclohexylethyl)‐2‐trimethylsilylmethyl‐1H‐1, 3, 2‐diazaborol (9) 1, 3‐Bis(1‐me‐thyl‐1‐phenyl‐propyl)‐2‐trimethylsilylmethyl‐1H‐1, 3, 2‐diazaborol (10) und 2‐Brom‐1, 3‐bis(1‐methyl‐1‐phenyl‐propyl)‐1H‐1, 3, 2‐diazaborol (11) entstehen durch Reaktion der entsprechenden 1, 4‐Diazabutadiene mit den Boranen Me3SiCH2BBr2, iBuBBr2 bzw. BBr3 und die nachfolgende Reduktion der resultierenden Boroliumsalze $\rm [R^{1}\overline{N=CH-CH=N(R^{1})B}R^{2}Br]Br$ [R1 = tBu, Me(cHex)CH, [Me(Et)Ph]C; R2 = Me3SiCH2, iBu, Br] mit Natriumamalgam. Reaktion der 2‐Brom‐1, 3, 2‐diazaborole 11 und 12 mit Silbercyanid liefert die 2‐Cyano‐1, 3, 2‐diazaborole 13 und 14. Die Alkylierung von 12 mit Isobutyllithium stellt eine Alternativsynthese für Verbindung 8 dar, während äquimolare Mengen 13 mit Isobutyllithium zur Bildung von 15 führen. Die neuen Verbindungen wurden durch Elementaranalysen sowie 1H‐, 13C‐, 11B‐NMR‐, IR‐ und Massenspektren charakterisiert. Die Molekülstrukturen der Verbindungen 7 und meso‐10 wurden durch Röntgenbeugung ermittelt.
Tetraazadibora[3, 3]paracyclophane
Authors: Paetzold Peter , Welling‐Osterloh Ute , Englert Ulli 
Published: December 2004

AbstractStarting from the para‐phenylenediamine derivative HN(SiMe3)‐C6H4‐NH(SiMe3), a lithiation and subsequent borylation give [(MeO)2B]N(SiMe3)‐C6H4‐N(SiMe3)[B(OMe)2] (1), the hydridation of which yields Li2[(H3B)N(SiMe3)‐C6H4‐N(SiMe3)(BH3)] (2). Applying ZrCl4 upon 2 initiates a condensation to give the title compound [‐N(SiMe3)‐p‐C6H4‐N(SiMe3)‐BH‐]2, a hetero[3, 3]paracyclophane with two N‐B‐N chains that connect the para‐phenylene units. The product 3 crystallizes in the orthorhombic space group P212121.
First Characterization of an Extended Ammonium‐Ammonia Complex [{NH4(NH3)4}+(μ‐NH3)2] in the Crystal Structure of [NH4(NH3)4][Co(C2B9H11)2] · 2 NH3
Authors: Roßmeier Thomas , Korber Nikolaus 
Published: December 2004

AbstractThe compound [NH4(NH3)4][Co(C2B9H11)2] · 2 NH3 (1) was prepared by the reaction of Na[Co(C2B9H11)2] with a proton‐charged ion‐exchange resin in liquid ammonia. The ammoniate 1 was characterized by low temperature single‐crystal X‐ray structure analysis. The anionic part of the structure consists of [Co(C2B9H11)2]‐ complexes, which are connected via C‐H···H‐B dihydrogen bonds. Furthermore, 1 contains an infinite [{NH4(NH3)4}+(μ‐NH3)2] cationic chain, which is formed by [NH4(NH3)4]+ ions linked by two ammonia molecules. The N‐H···N hydrogen bonds range from 1.92 to 2.71Å (DHA = Donor···Acceptor angles: 136‐176°). Additional N‐H···H‐B dihydrogen bonds are observed (H···H: 2.3‐2.4Å).