bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semiclassical path integral theory of a double‐well potential in an electric field
Authors: Douvropoulos Theodosios G. , Nicolaides Cleanthes A. 
Published: November 2005

AbstractA recently published methodology based on semiclassical path integral (SCPI) theory was implemented in the case of a model of a double‐well potential perturbed by a static electric field, with application to the inversion frequency of NH3. This model was chosen as an idealized case for testing of the present approach, as well as for quantum mechanical models that might be applied in the future. The calculations were concerned with the variation of the frequency of inversion as a function of field strength, F, and of distance, xf (from the symmetric point xo = 0), where the field is “felt.” It is found that this variation occurs sharply in very small regions of values of these parameters, and the system switches from internal oscillation to diffusion to the continuum. The fact that the theory is in analytic form allows the extraction of results and conclusions not only at the full SCPI level, but also at the Jeffreys–Wentzel–Kramers–Brillouin (JWKB) level. Comparison shows that the discrepancy sets in as the field strength increases, in accordance with the well‐known limitations of the JWKB method regarding its dependence on the degree of variation of the potential as a function of position. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Energy levels of the hydrogen atom in a cylindrical cavity
Authors: Yurenev P. V. , Scherbinin A. V. , Pupyshev V. I. 
Published: November 2005

AbstractElectronic states of the cylindrically confined hydrogen atom are studied numerically by the finite difference (FD) approach. Energies of the low‐lying states of the system are estimated vs. the radius R and length Z of the cylinder, as well as the position of the nucleus at the axis. Under the isotropic stretch of the cylinder with the constant ratio R = Z/2, the energy level picture reminds us that in the spherically confined atom: the energies of all states regularly grow up when decreasing the size of the cavity, and the states with the same principal n, but higher values of the angular l quantum number correspond to lower energies almost everywhere. Anisotropic stretch of the cylinder from prolate to the oblate one with constant volume causes numerous level intersections and avoided crossings, with the levels ordered as 1σ, 2π, 3δ, 2σ,…, in the prolate limit case, and as 1σ, 2π, 2σ, 3δ, 3π, 3σ,…, in the oblate limit case. The results of numerical calculations are in excellent agreement with qualitative consideration of the one‐electron system in the impenetrable cavity by using both variational and perturbative approaches. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Large‐scale identification of human biliary proteins from a cholesterol stone patient using a proteomic approach
Authors: Zhou Hu , Chen Bin , Li Rong‐Xia , Sheng Quan‐Hu , Li Su‐Jun , Zhang Lei , Li Long , Xia Qi‐Chang , Wang Hong‐Yang , Zeng Rong 
Published: November 2005

AbstractGallbladder bile, one of the most important body fluids, is composed of water, inorganic ions, conjugated bile salts, phospholipids, cholesterol, bilirubin, mucin and proteins. The separation and identification of bile proteins remain difficult due to the complexity of this matrix. In the present study, human gallbladder bile was obtained from a cholesterol stone patient, and the proteins were isolated and purified by dialysis, precipitation and delipidation procedures. The resulting proteins were divided into several aliquots. One aliquot was subjected to two‐dimensional gel electrophoresis (2DE). The protein spots were then in‐gel digested and analyzed by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). Another aliquot was directly digested and analyzed by a combination of strong cation‐exchange (SCX) and reversed‐phase (RP) chromatography prior to tandem mass spectrometry (2D‐LC/MS/MS). Eventually, 48 and 218 unique proteins were identified from 2DE/MS and 2D‐LC/MS/MS, respectively, resulting in a total of 222 unique identified proteins. Of the 218 proteins identified by 2D‐LC/MS/MS, 92 were identified based on more than one unique tryptic peptide, and, of the total 222 proteins, 98 were identified based on more than one unique tryptic peptide. Copyright © 2005 John Wiley & Sons, Ltd.
Characterization of intact Penicillium spores by matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Chen Hun‐Yun , Chen Yu‐Chie 
Published: November 2005

AbstractThe fungal spores of Penicillium expansum, P. chrysogenum, P. citrinum, P. digitatum, P. italicum, and P. pinophilum were characterized by using matrix‐assisted laser desorption/ionization with time‐of‐flight mass spectrometry (MALDI‐TOFMS). These fungal spores are frequently found in grain and fruit. The mass spectra of these six species were directly obtained from the intact spores without any pretreatment. The results obtained indicate that 2,5‐dihydroxybenzoic acid and sinapinic acid are suitable matrices for the analysis of Penicillium spores. Characteristic ions representing the different species were obtained with sufficiently high reproducibility that these ions can be employed to identify the different fungal species. On the basis of these characteristic ions obtained from these authentic Penicillium spores, the approach was applied to characterize the fungal species contaminating the surfaces of fruit. It was demonstrated that the fungal spores directly scratched from the surfaces of fruit contaminated by unknown fungi can be rapidly identified using MALDI‐TOFMS analysis without any tedious pretreatment. Copyright © 2005 John Wiley & Sons, Ltd.
Use of electrospray ionization mass spectrometry for profiling of crude oil effects on the phospholipid molecular species of two marine bacteria
Authors: Mazzella Nicolas , Molinet Josiane , Syakti Agung Dhamar , Dodi Alain , Bertrand Jean‐Claude , Doumenq Pierre 
Published: November 2005

AbstractWe investigated the membrane lipid composition of two hydrocarbon‐degrading gram‐negative bacterial strains (Pseudomonas nautica IP 617 and Marinobacter hydrocarbonoclasticus) initially cultured on a soluble substrate, then on petroleum hydrocarbons, and finally taken back onto the soluble substrate. For the two strains, the growth on petroleum and the return to the initial medium showed major, but comparable, qualitative and quantitative modifications of the intact phospholipid molecular species (IPMS) composition. Furthermore, since bacterial membranes are mainly made up of phospholipids, these modifications reflected hydrocarbon assimilation, restoration abilities and membrane fluidity adaptation. The electrospray ionization mass spectrometry (ESI‐MS) analysis of intact phospholipid provided some new information (e.g. sn fatty acyl chain distribution) that could not be assessed by the classical fatty acid analysis. Moreover, such information should be particularly helpful with regards to bacterial taxonomy and xenobiotic toxicity studies. Copyright © 2005 John Wiley & Sons, Ltd.
Electrospray tandem mass spectrometry of underivatised acetylated xylo‐oligosaccharides
Authors: Reis Ana , Pinto Paula , Evtuguin D. V. , Neto Carlos P. , Domingues P. , Ferrer‐Correia A. J. , Domingues M. Rosário M. 
Published: November 2005

AbstractAcetylated neutral (XylnAcm) and acidic xylo‐oligosaccharides (XylnAcmMeGlcA, and XylnAcmMeGlcAHex) obtained by partial acid hydrolysis of Eucalyptus globulus wood glucuronoxylans and fractionated by preparative ligand exchange/size‐exclusion chromatography were identified by electrospray ionisation mass spectrometry (ESI‐MS). Low molecular weight acetylated xylo‐oligosaccharides were studied by ESI‐tandem mass spectrometry (MS/MS). All the acetylated xylo‐oligosaccharides showed an abundant ion due to the neutral loss of 60 Da (CH3CO2H) in the MS/MS spectra. The presence of diacetylated xylo‐oligosaccharides was confirmed by the ions formed by loss of two molecules of acetic acid. Furthermore, characteristic [XylresAc2+Na]+ and [XylAc2+Na]+ ions, and ions due to loss of XylAc2, indicate that both acetyl groups are located in the same Xyl residue. On the other hand, losses of XylresAc and XylAc are also observed as well as [XylresAc+Na]+ and [XylAc+Na]+ , indicating the location of both acetyl groups in different Xyl residues, in some cases even in adjacent xyloses. The MS/MS spectra of triacetylated xylo‐oligosaccharides were complex due to the presence of different isobaric xylo‐oligosaccharides containing the acetyl groups at different locations in the xylo‐oligosaccharide backbone. In the MS/MS spectra of acidic xylo‐oligosaccharides, the ion at m/z 387, [XylresAcMeGlcA+Na]+, indicates that the acetyl groups are preferentially linked to Xyl substituted with MeGlcA. However, acidic xylo‐oligosaccharides with the acetyl and 4‐O‐methylglucuronic acid groups in different Xyl residues were also identified. In neutral and in acidic xylo‐oligosaccharides several possible locations of the acetyl groups were identified, namely at terminal positions. In summary, ESI‐MS/MS is shown to be a powerful tool for the characterisation of acetylated patterns in complex mixtures of oligosaccharides. Copyright © 2005 John Wiley & Sons, Ltd.
Analysis of proteins from a glioma cell line by using micro‐scale solution isoelectric focusing in combination with liquid chromatography/tandem mass spectrometry
Authors: Westman‐Brinkmalm Ann , Karlsson Gösta , Brive Lena M. , Hedberg‐Fogel Kristina , Persson Rita , Karlsson Hasse , Ekman Rolf , Blennow Kaj 
Published: November 2005

AbstractIn this study we have investigated whether micro‐solution isoelectric focusing (µsol‐IEF) can be used as a pre‐fractionation step prior to liquid chromatography/tandem mass spectrometry (LC/MS/MS) and if extensive sample purification of the different fractions is required. We found that, in spite of the high concentrations of buffer and detergents, no clean up of the digested µsol‐IEF fractions was necessary before analysis by LC/MS/MS. We also concluded that it is possible to identify at least twice as many proteins in a glioma cell lysate with the combination of µsol‐IEF and LC/MS/MS than with LC/MS/MS alone. Furthermore, most of the proteins that were identified from one µsol‐IEF fraction by using analytical narrow‐range two‐dimensional polyacrylamide gel electrophoresis (2D‐PAGE) and peptide mass fingerprinting with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) were also identified by LC/MS/MS. Finally, we used the combination of µsol‐IEF and LC/MS/MS to compare two sample preparation methods for glioma cells and found that several nuclear, mitochondria, and endoplasmic reticulum proteins were only present in the sample that had been subjected to lipid extraction by incubating the homogenized cells in chloroform/methanol/water. Copyright © 2005 John Wiley & Sons, Ltd.
Characterisation and proposed origin of mass spectrometric ions observed 30 Th above the ionised molecules of per‐O‐methylated carbohydrates
Authors: Robinson Sarah , Routledge Anne , Thomas‐Oates Jane 
Published: November 2005

AbstractDerivatisation of carbohydrates by permethylation significantly improves the mass spectrometric intensity of carbohydrate‐derived ions and allows more readily interpretable fragmentation; in addition, samples are conveniently separated from salts, and larger oligosaccharides are more readily ionised. It has previously been recognised that, in the mass spectra of permethylated carbohydrates, a series of ions indicating species 30 Da larger than the fully methylated carbohydrate molecules are also observed. These species have not been characterised in the literature despite their apparently ubiquitous occurrence in the mass spectra of permethylated carbohydrates. Tandem mass spectrometry (MS/MS) experiments were performed on permethylated carbohydrates and reduced permethylated carbohydrates that exhibit the artefact, demonstrating that the artefact is not reducing terminal specific, and that the artefact can be introduced at any hydroxyl residue. It was further demonstrated through the use of different alkylation reagents that the origin of this artefact group is the alkylating reagent itself. It is proposed that side reactions that occur between the permethylation reagents allow the production of small amounts of iodomethyl methyl ether. This reagent can then compete with methyl iodide for reaction with the carbohydrate OH groups. The result is partial incorporation of a methoxymethyl moiety instead of a methyl group, detected as ‘+30’ artefact ions. Copyright © 2005 John Wiley & Sons, Ltd.
Threshold values of random K‐SAT from the cavity method
Authors: Mertens Stephan , Mézard Marc , Zecchina Riccardo 
Published: November 2005

AbstractUsing the cavity equations of Mézard, Parisi, and Zecchina Science 297 (2002), 812; Mézard and Zecchina, Phys Rev E 66 (2002), 056126 we derive the various threshold values for the number of clauses per variable of the random K‐satisfiability problem, generalizing the previous results to K ≥ 4. We also give an analytic solution of the equations, and some closed expressions for these thresholds, in an expansion around large K. The stability of the solution is also computed. For any K, the satisfiability threshold is found to be in the stable region of the solution, which adds further credit to the conjecture that this computation gives the exact satisfiability threshold.© 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
The impact of endogenous demand on push–pull production systems
Authors: Gonçalves Paulo , Hines Jim , Sterman John 
Published: November 2005

AbstractThough often analyzed separately, supply chain instability and customer demand interact through product availability. We investigate the feedback between supply chain performance and demand variability in a model grounded in a first‐hand study of the hybrid push–pull production system used by a major semiconductor manufacturer. While customers' response to variable service levels represents an important concern in industry, with sizeable impacts on company profitability, previous models exploring supply chain instability do not account for it. This research incorporates two effects of customer responses to availability. The sales effect captures the negative feedback whereby product shortages cause customers to seek alternative sources of supply, reducing demand and easing the shortage. The production effect captures the delayed impact of changes in demand on the manufacturer's production decisions: lower demand leads to reduced production, prolonging shortages that depress demand, a destabilizing positive feedback. We show how the sales and production effects interact to destabilize the supply chain and lower average performance. Supply chain models that assume exogenous demand may therefore underestimate the amplification in the chain and the value of inventory buffers. In addition, incorporating the customer response leads to different inventory and utilization policies from those in use by the company. The model yields insights into the costs of lean inventory and responsive utilization policies in the context of hybrid production systems and endogenous demand. Copyright © 2005 John Wiley & Sons, Ltd.
Upstream versus downstream information and its impact on the bullwhip effect
Authors: Croson Rachel , Donohue Karen 
Published: November 2005

AbstractThis paper reports the results of an experiment to examine whether giving supply chain partners access to downstream inventory information is more effective at reducing bullwhip behavior, and its associated costs, than similar access to upstream inventory information. Bullwhip behavior refers to the tendency of orders to increase in variation as they are passed upstream in a supply chain (i.e., away from the final consumer). We use a controlled version of the Beer Distribution Game as the setting for our experiment, and vary the amount and location of inventory information shared across treatments. We first independently test whether sharing upstream or downstream inventory information helps reduce bullwhip behavior, and find that only downstream information sharing leads to significantly lower order oscillations throughout the supply chain. We then compare the reduction in order oscillations experienced by supply chain level and find that upstream supply chain members benefit the most from downstream information sharing. Copyright © 2005 John Wiley & Sons, Ltd.
Studies of carbon behaviour on GaN surface in ultra high vacuum (UHV)
Authors: Diale M. , Auret F. D. , Odendaal R. Q. , Roos W. D. 
Published: November 2005

AbstractIn this study, AES was used to thermally clean GaN surfaces, and analysis was done as the temperature was gradually increased. Heating samples to 1010 °C resulted in nearly stoichiometric and contamination‐free surfaces. The behaviour of carbon on the GaN surface was studied with sputtering in AES. It was found that C was a surface issue than a crystal problem. XPS was used to identify the chemical state of the contaminants on the surface of as‐grown GaN. These were found to be in the form of gallium oxides, hydroxides, graphite and carbides. Copyright © 2005 John Wiley & Sons, Ltd.
Rh2[MTPA]4, a dirhodium complex as NMR auxiliary for chiral recognition
Authors: Duddeck Helmut 
Published: November 2005

AbstractThe dirhodium complex Rh(+II)2[(+)‐MTPA]4 is introduced as an NMR auxiliary for enantiodifferentiation. As a soft Lewis acid, it is particularly useful for the recognition of soft Lewis base molecules. The donor properties of ligands can be divided into several categories and are exemplified by various classes of phosphorus‐containing functionalities. In addition, the thermodynamics of the underlying ligand–complex equilibria are discussed and stereochemical implications demonstrated. The extension of the dirhodium method to absolute configuration determination is evaluated. The outlook for future applications with further non‐phosphorus ligands is presented. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 396–409; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20059
Natural and edible biopolymer poly‐γ‐glutamic acid: synthesis, production, and applications
Authors: Sung Moon‐Hee , Park Chung , Kim Chul‐Joong , Poo Haryoung , Soda Kenji , Ashiuchi Makoto 
Published: November 2005

AbstractPoly‐γ‐glutamic acid (γ‐PGA) is a very promising biodegradable polymer that is produced by Bacillus subtilis. γ‐PGA is water‐soluble, anionic, biodegradable, and edible. This paper reviews the production of a strain of γ‐PGA and recent developments with respect to applications in terms of Ca absorption, moisturizing properties, γ‐PGA conjugation, super absorbent polymer, and so on. Our recent research shows that γ‐PGA can be used as an immune‐stimulating and anti‐tumor agent, especially at high molecular weight. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 352–366; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20061
Cervical assessment at 22 and 27 weeks for the prediction of spontaneous birth before 34 weeks in twin pregnancies: is transvaginal sonography more accurate than digital examination?
Authors: Vayssière C. , Favre R. , Audibert F. , Chauvet M. P. , Gaucherand P. , Tardif D. , Grangé G. , Novoa A. , Descamps P. , Perdu M. , Andrini E. , Janse‐Marec J. , Maillard F. , Nisand I. 
Published: November 2005

AbstractObjectivesThis study compared the accuracy of ultrasound cervical assessment (cervical length and cervical index) and digital examination (Bishop score and cervical score) in the prediction of spontaneous birth before 34 weeks in twin pregnancies.MethodsIn a prospective multicenter study, digital examination and transvaginal sonography were performed consecutively in twin pregnancies attending for routine sonography at either 22 weeks (175 women) or 27 weeks (153 women). The digital examination took place first, and the Bishop score and cervical score (cervical length minus cervical dilatation) were calculated. Ultrasound measurements were then made of cervical length and funnel length to yield the cervical index (1 + funnel length/cervical length). The association between each variable and delivery before 34 weeks was tested by the Mann–Whitney U‐test. The receiver–operating characteristics (ROC) curves of the ultrasound and digital indicators were determined for both gestational age periods, and the areas under the ROC curves compared. The best cut‐off values for each indicator were used to determine predictive values for delivery before 34 weeks.ResultsThe median gestational age at delivery among the women included in the 22‐week examination period was 36.0 (range, 21–40) weeks; 10.9% (19) gave birth spontaneously before 34 weeks. The median cervical length was 40 (range, 6–65) mm. All four parameters were predictors of delivery before 34 weeks. The areas under the ROC curves for cervical index, cervical length, Bishop score and cervical score did not differ significantly. The median gestational age at delivery among the women in the 27‐week examination period was 36.0 (range, 27–40) weeks; 9.2% (14) gave birth spontaneously before 34 weeks. The median cervical length was 35 (range, 1–57) mm. All parameters except the Bishop score were predictors of delivery before 34 weeks. The likelihood ratio of the positive and negative tests for cervical length ≤ 25 mm was 5.4 (range, 3.2–9.0) and 0.3 (range, 0.1–0.7), respectively, compared with 2.3 (range, 1.3–4.2) and 0.6 (range, 0.3–1.1), respectively, for cervical score ≤ 1. The area under the curve for the cervical index was significantly larger than that for the Bishop score (P = 0.008) or cervical score (P = 0.02).ConclusionTransvaginal sonography predicted spontaneous delivery before 34 weeks better than digital examination at the 27‐week but not the 22‐week examination. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Sonographic characteristics of linear nevus sebaceous sequence
Authors: Neis A. E. , Johansen K. L. , Harms R. W. , Watson W. J. , Brost B. C. 
Published: November 2005

AbstractLinear nevus sebaceous is a hamartomatous lesion most commonly seen on the face and head of infants and diagnosed after birth. We describe a patient with sonographic findings of linear nevus sebaceous seen initially at 30 weeks' gestation. Other associated sonographic findings include macrocephaly and polyhydramnios. When associated with a midline soft tissue mass, these findings are highly suggestive of the presence of congenital linear nevus sebaceous sequence. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.