bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical study on dependence of hyperpolarizability of one‐dimensional ring system on the delocalization transition
Authors: Nagao Hidemi , Ohta Yasuhito , Yoshimoto Takashi , Saito Hiroaki , Maki Jun , Kawabe Hiroyuki , Ohta Koji , Nishikawa Kiyoshi 
Published: August 2002

AbstractWe calculate the optical properties such as the polarization, the (hyper)polarizabilities, the critical vector potential, etc., in terms of the non‐Hermitian Anderson model of a 6‐site ring model. The dependence of the optical properties on the delocalization transition is investigated. It is found that all the total optical properties nonlinearly increase with the increase of the delocalization. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Reaction mechanisms between methylamine and a few Schiff bases: Ab initio potential energy surfaces of a catalytic step in semicarbazide sensitive amino oxidases (SSAO)
Authors: Alagona Giuliano , Ghio Caterina 
Published: August 2002

AbstractThe potential energy surfaces for the transamination reaction catalyzed by SSAO were explored for some of the possible reactants considered in a preliminary investigation (Comput Chem 2000, 24, 311). The proton transfer to methylamine (as a model of the catalytic base belonging to the enzyme active site)—either from the keto or enol form of the reactant Schiff bases with one of the possible cofactors, pyridoxal phosphate, PLP (using as a model the pyridoxal ring protonated at N)—was investigated. The enol form seems to be preferred in the region of the neutral intermediate, because even the keto form undergoes a spontaneous rearrangement to the enol form once the Cα proton is delivered to methylamine, producing methylammonium. When the proton is returned back to the Schiff base (on C1), the adduct is about 1.4 kcal/mol more stable than the reactants, while a canonical electron distribution is obtainable only for the enol form. The proton transfer to methylamine was also studied in the presence of the other possible cofactor (para or ortho) topaquinone, TQ. A steep uphill pathway, similar to the keto‐pyridoxal Schiff base one, is obtained using the Schiff base with pTQ, which requires a rearrangement to the final intermediate. On the contrary, using the oTQ structures with the quinonoid O on the same side of methylamine, the proton abstracted from the Schiff base goes spontaneously onto the other quinonoid oxygen. The effect on the barrier heights produced by the presence of a variety of functional groups in the vicinity of the pyridoxal ring nitrogen was also examined. © 2001 John Wiley & Sons, Inc. Int J Quant Chem, 2001
Solvent effect on DNA base stacked dimers: An isodensity polarizable continuum model approach
Authors: Sivanesan D. , Subramanian V. , Nair B. U. 
Published: August 2002

AbstractThe role of solvent on the base stacking properties of various stacked dimers has been analyzed. Ab initio calculations have been performed on the various stacked dimers using the isodensity polarizable continuum model (IPCM), in the framework of the HF/6‐31G** level. It is observed that the stacked dimers undergo different levels of stabilization for different rotated conformations, and the total energy of stacked dimers depends on the twist angle. The results reveal that DNA stacked dimers prefer the twisted (rotated conformation) conformation in water environment, so as to escape from water, due to their hydrophobic nature. In addition, the presence of solvent stabilizes the stacking interaction between bases. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Facile sequencing of oligosaccharides by matrix‐assisted laser desorption/ionisation on a hybrid quadrupole orthogonal acceleration time‐of‐flight mass spectrometer
Authors: Hanrahan Sarah , Charlwood Joanne , Tyldesley Richard , Langridge James , Bordoli Robert , Bateman Robert , Camilleri Patrick 
Published: August 2002

AbstractN‐Linked oligosaccharide mixtures released from a number of standard glycoproteins were derivatised with 3‐acetylamino‐6‐acetylaminoacridine (AA‐Ac) using reductive amination. Analysis of these mixtures using an experimental matrix‐assisted laser desorption/ionisation (MALDI) hybrid quadrupole orthogonal acceleration time‐of‐flight (Q‐TOF) mass spectrometer provided detailed information about the mass distribution of the glycan derivatives. Collision‐induced dissociation of the singly protonated [M + H]+ ions also gave rise to a number of product ions produced by the sequential cleavage of the glycosidic linkages. As fragmentation of the positively charged species occurred predominantly in one direction, i.e., from the non‐reducing end of the glycan to the AA‐Ac moiety, a considerable amount of information could be obtained with ease about the sequence in which the sugar residues were attached to one another. This derivatisation procedure and mass spectrometric methodology were applied successfully to neutral and acidic glycans released from proteins separated by gel electrophoresis. Copyright © 2001 John Wiley & Sons, Ltd.
Simultaneous assessment of cholesterol absorption and synthesis in humans using on‐line gas chromatography/ combustion and gas chromatography/pyrolysis/isotope‐ratio mass spectrometry
Authors: Gremaud G. , Piguet C. , Baumgartner M. , Pouteau E. , Decarli B. , Berger A. , Fay L. B. 
Published: August 2002

AbstractA number of dietary components and drugs are known to inhibit the absorption of dietary and biliary cholesterol, but at the same time can compensate by increasing cholesterol synthesis. It is, therefore, necessary to have a convenient and accurate method to assess both parameters simultaneously. Hence, we validated such a method in humans using on‐line gas chromatography(GC)/combustion and GC/pyrolysis/isotope‐ratio mass spectrometry (IRMS). Cholesterol absorption was measured using the ratio of [13C]cholesterol (injected intravenously) to [18O]cholesterol (administered orally). Simultaneously, cholesterol synthesis was measured using the deuterium incorporation method. Our methodology was applied to 12 mildly hypercholesterolemic men that were given a diet providing 2685 ± 178 Kcal/day (mean ± SD) and 255 ± 8 mg cholesterol per day. Cholesterol fractional synthesis rates ranged from 5.0 to 10.5% pool/day and averaged 7.36% ± 1.78% pool/day (668 ± 133 mg/day). Cholesterol absorption ranged from 36.5–79.9% with an average value of 50.8 ± 15.4%. These values are in agreement with already known data obtained with mildly hypercholesterolemic Caucasian males placed on a diet similar to the one used for this study. However, our combined IRMS method has the advantage over existing methods that it enables simultaneous measurement of cholesterol absorption and synthesis in humans, and is therefore an important research tool for studying the impact of dietary treatments on cholesterol parameters. Copyright © 2001 John Wiley & Sons, Ltd.
Structural elucidation of monoterpene oxidation products by ion trap fragmentation using on‐line atmospheric pressure chemical ionisation mass spectrometry in the negative ion mode
Authors: Warscheid Bettina , Hoffmann Thorsten 
Published: August 2002

AbstractBased on ion trap mass spectrometry, an on‐line method is described which provides valuable information on the molecular composition of structurally complex organic aerosols. The investigated aerosols were generated from the gas‐phase ozonolysis of various C10H16‐terpenes (α‐pinene, β‐pinene, 3‐carene, sabinene, limonene), and directly introduced into the ion source of the mass spectrometer. Negative ion chemical ionisation at atmospheric pressure (APCI(−)) enabled the detection of multifunctional carboxylic acid products by combining inherent sensitivity and molecular weight information. Sequential low‐energy collision‐induced product ion fragmentation experiments (MSn) were performed in order to elucidate characteristic decomposition pathways of the compounds. Dicarboxylic acids, oxocarboxylic acids and hydroxyketocarboxylic acid products could be clearly distinguished by multistage on‐line MS. Furthermore, sabinonic acid and two C9‐ether compounds were tentatively identified for the first time by applying on‐line APCI(−)‐MSn. Copyright © 2001 John Wiley & Sons, Ltd.
Determination of selected sulfonamide antibiotics and trimethoprim in manure by electrospray and atmospheric pressure chemical ionization tandem mass spectrometry
Authors: Pfeifer Thomas , Tuerk Jochen , Bester Kai , Spiteller Michael 
Published: August 2002

AbstractA method for the determination of sulfonamides and trimethoprim in the complex matrix liquid manure has been developed using reversed‐phase liquid chromatography and atmospheric pressure chemical ionization (APCI) tandem mass spectrometry. A comparison was made between electrospray and atmospheric pressure chemical ionization. APCI proved to be more robust and less sensitive to matrix effects. High‐performance liquid chromatographic (HPLC) separation of the analytes was achieved in less than 7 min. The compounds were extracted with ethyl acetate and the extracts were cleaned up by solid‐phase extraction on an aminopropyl column. Recoveries were not dependent on the concentration level. The mean recoveries were as follows: trimethoprim 79.0%, sulfadiazine 80.5%, N4‐acetylsulfadiazine 91.0%, sulfamerazine 78.6%, sulfadimidine 77.2% and sulfamethoxazole 82.8%. Linearity was established over a concentration range of 5 to 5000 µg/kg with correlation coefficients greater than 0.99. The method had a limit of quantitation (LOQ) of 5 µg/kg manure. Copyright © 2002 John Wiley & Sons, Ltd.
Electrospray mass spectrometric studies of L‐carnosine (β‐alanyl‐L‐histidine) complexes with copper(II) or zinc ions in aqueous solution
Authors: Mineo P. , Vitalini D. , La Mendola D. , Rizzarelli E. , Scamporrino E. , Vecchio G. 
Published: August 2002

AbstractElectrospray ionization mass spectrometry (ESI‐MS) was used for the speciation of supramolecular assemblies formed between equimolar amounts of carnosine and copper or zinc ions in dilute aqueous solutions. In the case of pure carnosine and carnosine/copper systems, the effect of pH changes, in the range 2–9, on the complexes surviving in solution was also explored. ESI data, besides supporting previous reported results on the formation of dimeric carnosine/copper and carnosine/zinc complexes, allowed a more complete speciation of the examined systems, bringing to light the existence of bis‐complex species and, in the zinc case, the formation of oligomeric species. The data obtained for the systems investigated show that ESI‐MS is not only a reliable and fast technique for the analysis of the metal/ligand systems, but also an interesting tool to obtain stoichiometric information on metal complexes formed in very low concentration solutions. Copyright © 2002 John Wiley & Sons, Ltd.
Short capillary ion‐pair high‐performance liquid chromatography coupled to electrospray (tandem) mass spectrometry for the simultaneous analysis of nucleoside mono‐, di‐ and triphosphates
Authors: Tuytten R. , Lemière F. , Dongen W. Van , Esmans E. L. , Slegers H. 
Published: August 2002

AbstractA liquid chromatography/mass spectrometry (LC/MS) method for the analysis of complex mixtures of nucleoside mono‐, di‐ and triphosphates has been developed. A short capillary column (35mm × 0.3mm i.d.) was operated under ion‐pair high‐performance liquid chromatography conditions and hyphenated to (negative) electrospray (tandem) mass spectrometry. As such, the separation of 12 nucleotides was performed by a binary gradient elution using CH3OH/H2O and N,N‐dimethylhexylamine (N,N‐DMHA) as ion‐pairing agent. The influence of different N,N‐DMHA concentrations on the chromatographic and mass spectrometric performance was evaluated to achieve optimal LC/MS conditions. In addition it was demonstrated that a controlled admission of ammonium dihydrogen phosphate (NH4H2PO4) improved both chromatographic performance and mass spectrometric detection. Because the system was hyphenated to an orthogonal designed electrospray interface (Z‐spray™), long acquisition times were possible without loss of sensitivity. Copyright © 2002 John Wiley & Sons, Ltd.
Dynamic positioning of a turret moored FPSO using sliding mode control
Authors: Tannuri E. A. , Donha D. C. , Pesce C. P. 
Published: August 2002

AbstractThis paper presents the application of a sliding mode control technique to the dynamic positioning of a turret moored FPSO. The proposed controller is robust with respect to modelling errors and variations in the intensity and direction of environmental forces. Since the system is strongly non‐linear, the sliding mode methodology is appropriate because it does not require linearization and uses the complete model for the controller design. Furthermore, the design of the controller term that guarantees robustness is very simple, and can be generalized to any adopted model of dynamic and environmental forces. The main drawback of the sliding controller, related to the high oscillatory control action, is avoided by the definition of a “boundary layer” near the sliding surface. The controller was tested through numerical simulations of a moored VLCC under several environmental conditions, confirming the stability and performance robustness. Copyright © 2001 John Wiley & Sons, Ltd.
A dexterous humanoid shoulder mechanism
Authors: Stanišić M. M. , Wiitala J. M. , Feix J. T. 
Published: August 2002

AbstractThis paper presents a mechanism that has the potential to serve as a simple humanoid shoulder joint. Unlike the
ball‐in‐socket joint or universal joint, this mechanism can replicate the range of dexterous shoulder
motion found in humans. The mechanism's kinematic equations of motion are studied for singular configurations
and a prototype system is presented. © 2001 John Wiley & Sons, Inc.
A generic approach for the unranking of labeled combinatorial classes
Authors: Martínez Conrado , Molinero Xavier 
Published: August 2002

AbstractIn this article, we design and analyze algorithms that solve the unranking problem (i.e., generating a combinatorial structure of size, n given its rank) for a large collection of labeled combinatorial classes, those that can be built using operators like unions (+), products (⋆), sequences, sets, cycles, and substitutions. We also analyze the performance of these algorithms and show that the worst‐case is 𝒪(n2) (𝒪(n log n) if the so‐called boustrophedonic order is used), and provide an algebra for the analysis of the average performance and higher‐order moments together with a few examples of its application. © 2001 John Wiley & Sons, Inc. Random Struct. Alg., 19: 472–497, 2001
Martingales and large deviations for binary search trees
Authors: Jabbour‐Hattab Jean 
Published: August 2002

AbstractWe establish an almost sure large deviations theorem for the depth of the external nodes of binary search trees (BSTs). To achieve this, a parametric family of martingales is introduced. This family also allows us to get asymptotic results on the number of external nodes at deepest level. © 2001 John Wiley & Sons, Inc. Random Struct. Alg., 19: 112–127, 2001
A class of systematic m‐ary single‐symbol error correcting codes
Authors: Namba Kazuteru , Fujiwara Eiji 
Published: August 2002

AbstractNowadays, m‐ary information such as postal numbers, ID numbers, telephone numbers, and book numbers is being widely used. Increasing the reliability of such information is very important. Single‐symbol error correcting codes for such m‐ary information (m>2) proposed in the past have some limitations. For example, AN codes are nonsystematic, and Hamming codes cannot be constructed over integer rings in which the base is other than prime numbers or power multiples of prime numbers. This paper presents a new class of systematic m‐ary single‐symbol error correcting codes whose check symbols are determined under integer ring of modulo 2m and prime field, and then transformed into m‐ary symbols. This also shows that the proposed codes are superior to existing codes in terms of the code length when the base number m is not a prime or a power multiple of prime. In addition, the detection probabilities with respect to errors greater than the code function such as double symbol errors have been clarified. © 2001 Scripta Technica, Syst Comp Jpn, 32(6): 21–28, 2001
Evaluation of exchanging time for mechanism of exchanging parts of programs during execution
Authors: Taniguchi Hideo , Goto Masataka 
Published: August 2002

AbstractThe authors describe the relationship with program characteristics for a method of exchanging the parts of a program during execution. They then formulate the exchanging time and the thread stoppage time during which the thread is stopped so it can be exchanged. In application programs that share execution units (threads) allocated in a processor or in the case of operating system programs that can be preempted, parts of several programs must be exchanged at the same time. These program parts are shared among many threads. The exchanging time rises along with the processing time for the program part to be exchanged, and the impact on the number of threads which a program shares is minimal. The thread stoppage time during which a thread is stopped so it can be exchanged rises along with the number of shared threads and the processing time for the program parts to be exchanged. The formulation for the exchanging time and the thread stoppage time is shown to have results similar to real measurements. © 2001 Scripta Technica, Syst Comp Jpn, 32(8): 53–62, 2001
The control of goods transportation growth by modal share re‐planning: the role of a carbon tax
Authors: Piattelli Mauro L. , Cuneo Marta A. , Bianchi Nicola P. , Soncin Giuseppe 
Published: August 2002

AbstractA simple model is proposed, at the macrolevel of variables aggregation, as a support for policy choice making in the control of goods transportation growth by possible alternative modes. The impact of feasible changes in the levying of “carbon tax” can be investigated with the proposed model, as well as the effects of investments in infrastructure and of the coverage of operational costs. Based on some transport externalities, various cost indices are identified and suitably minimized using optimization techniques, so that a quantitative definition of public policies can be derived. As an example, the model is used to evaluate application of alternative policies in Germany. This case study shows that the model system of goods transportation has a slight sensitivity to the public interventions considered. The application of the carbon tax shows significant effects on the increase of fiscal revenues rather than on the reduction of carbon dioxide emissions and on the share of road transportation. Reductions in carbon dioxide emissions and in transportation by road are best achieved by higher investment in the infrastructures of alternative modes of transport, together with a reduction in fuel taxation. Copyright © 2002 John Wiley & Sons, Ltd.
Adhesion properties on nanometric scale of silicon oxide and silicon nitride surfaces modified by 1‐octadecene
Authors: Pignataro B. , Grasso G. , Renna L. , Marletta G. 
Published: August 2002

AbstractSilicon oxide and silicon nitride surfaces have been treated with 1‐octadecene at ∼200°C . The resulting film topography has been inspected by atomic force microscopy (AFM), showing a densely packed organic coating with a corrugation of some tenths of a nanometre. High‐mass‐resolution time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) spectra from such surfaces display octadecene‐ as well as substrate‐related peaks. Furthermore, peaks diagnostic of the formation of SiOC or SiC linkages are observed in the case of silicon oxide, whereas the same peaks and those due to SiNC species have been observed in the case of silicon nitride. These results suggest that 1‐octadecene molecules are chemisorbed on the substrate. Contact angle measurements and AFMforce spectroscopy measurements allow comparison upon the macroscopic and nanoscopic scale, respectively, of the surface free energy modification due to the formation of the organic coating. Copyright © 2002 John Wiley & Sons, Ltd.
Uses of SIMS three dimensional imaging to understand the relationships between grain boundary chemistry, orientation and intergranular degradation
Authors: McIntyre N. S. , Huctwith C. M. , Taylor K. F. , Keating E. , Petersen N. O. , Brennenstühl A. M. 
Published: August 2002

AbstractSecondary ion mass spectrometry (SIMS) image depth profiles have been made through grain structures on nickel alloy material that had displayed differing levels of intergranular stress corrosion cracking. The distributions of trace impurities, both within and outside the grain boundaries, are documented qualitatively through three‐dimensional imaging, and quantitatively through the use of cross‐correlation spectroscopy. Copyright © 2002 John Wiley & Sons, Ltd.
Quantitative surface chemical analysis of stainless steel 1.4301 using Surface Science Instruments XPS spectrometers: report on an interlaboratory comparison
Authors: Gross Th. , Unger W. E. S. , Patscheider J. 
Published: August 2002

AbstractResults of an interlaboratory comparison of XPS data obtained with stainless steel are presented. Only one photoelectron spectrometer model was used. The stainless‐steel sample surfaces were analysed in different states by XPS: ‘as received’, after sputtering to I(C 1s)/I(Fe 2p3/2) ∼0.025 and after removing a chromium‐enriched oxide layer following a certain protocol. The Fe, Cr and Ni elemental concentrations were evaluated from the respective XPS data submitted by the participants of the interlaboratory test experiment. Total means, repeat standard deviations (sr) and reproducibility standard deviations (sR) are presented. The best reproducibility standard deviations were obtained for the XPS analysis after removal of a chromium‐enriched oxide layer and quantification of the XPS intensities without taking the contamination elements of carbon and oxygen into account. The absolute reproducibility standard deviation of the elemental concentrations in that case is as small as 1.1–1.5 at.%. This gives 2%, 6% and 16% for the relative reproducibility standard deviation of the concentrations of iron, chromium and nickel, respectively. The total means of the iron, chromium and nickel concentrations finally obtained agree within 2sR with bulk values determined by wavelength‐dispersive x‐ray fluorescence spectroscopy. Comparison to an earlier interlaboratory test experiment shows that using only one model of photoelectron spectrometer reduces the reproducibility standard deviations efficiently. Copyright © 2002 John Wiley & Sons, Ltd.
Silicon wafer cleaning processes and ozone oxide growth as studied by angle‐resolved x‐ray photoelectron spectroscopy (ARXPS) and ellipsometry
Authors: Ermolieff A. , Marthon S. , Rochet X. , Rouchon D. , Renault O. , Michallet A. , Tardif F. 
Published: August 2002

AbstractKnowledge of silicon oxide layer thickness and stoichiometry is essential for the integration of new dielectric materials. Among the various ways of obtaining ultrathin silicon oxides, chemically grown oxides are a promising choice. Different cleaning processes of silicon wafer for microelectronic integrated‐circuit‐scale application were investigated by XPS and ellipsometry. In this work, overlayer thicknesses were deduced from XPS intensity photoelectron lines and ellipsometric measurements. A comparison between these techniques was carried out. Chemical compositions of the overlayers were deduced from XPS measurements, and an ellipsometric calibration is proposed according to the relative oxygen atomic concentration. Copyright © 2002 John Wiley & Sons, Ltd.