bluuebunny/crossref_metadata_2025_split huggingface dataset:
An automatic adaptive refinement finite element procedure for 2D elastostatic analysis
Authors: Lee C. K. , Lo S. H. 
Published: November 2005

AbstractAn automatic adaptive refinement procedure for finite element analysis is presented. The procedure is applied to two‐dimensional elastostatic problems to obtain solutions of prescribed accuracy. Through the combined use of new mesh generator using contour developed by Lo1 and the concept of strain energy concentration, high‐quality graded finite element meshes are generated. The whole process is fully automatic and no user intervention is required during the successive cycles of the mesh refinements. The Zienkiewicz and Zhu2 error estimator is found to be effective and has been adopted for the present implementation. In the numerical examples tested, the error estimator gives an accurate error norm estimation and the effectivity index of the estimator converges to a value close to unity.
The modelling of aerodynamic flows by solution of the euler equations on mixed polyhedral grids
Authors: Peace A. J. , Shaw J. A. 
Published: November 2005

AbstractIn this paper, an algorithm for obtaining solutions to the compressible Euler equations on mixed polyhedral grids is described. These grids, which are, in general, composed of hexahedral, pentahedral and tetrahedral elements, are used in the modelling of aerodynamic flows over complex three‐dimensional geometries. The hexahedra are grouped into regular blocks, while the other elements are part of irregular grid regions, giving rise to the term “hybrid grid approach”. The interconnection of the grid elements is defined by an efficient data structure, which supplies the required information to drive the Euler algorithm. In fact, cell‐vertex and cell‐centre spatial discretization variants of this algorithm are detailed, along with an explicit time‐marching scheme for obtaining steady‐state solutions. Results on two geometrically simple configurations provide an evaluation of these solution techniques, whilst the focus on a third, complex configuration, demonstrates the potential of the method in addressing the flow over general aircraft geometries.
Direct polycondensations of N,N′‐(4,4′‐oxydiphthaloyl)‐bis‐L‐leucine diacid by use of tosyl chloride in the presence of N,N‐dimethylformamide
Authors: Mallakpour Shadpour , Kowsari Elaheh 
Published: November 2005

Abstract4,4′‐Oxydiphthalic anhydride (1) was reacted with L‐leucine (2) in acetic acid and the resulting N,N′‐(4,4′‐oxydiphthaloyl)‐bis‐L‐leucine diacid (4) was obtained in high yield. The direct polycondensation reaction of this diacid with several aromatic diols such as bisphenol A (5a), phenolphthalein (5b), hydroquinone (5c), 4,4′‐dihydroxydiphenyl sulfide (5d), 4,6‐dihydroxypyrimidine (5e) and 4,4′‐dihydroxydiphenyl sulfone (5f) 2,4′‐dihydroxyacetophenone (5g) and 2,6‐dihydroxytoluene (5h) was carried out in a system of tosyl chloride (TsCl), pyridine and N,N‐dimethylformamide (DMF). The reactions with TsCl were significantly promoted by controlling alcoholysis with diols in the presence of the catalytic amounts of DMF to give a series of optically active poly(ester‐imide)s (PEI)s with good yield and moderate inherent viscosity ranging 0.36–0.78 dL/g. The polycondensation reactions were significantly affected by the amounts of DMF, the molar concentration of monomers, TsCl and pyridine, aging time, temperature and the reaction time. All of the above polymers were fully characterized by 1H‐NMR, FT‐IR, elemental analysis and specific rotation. Some structural characterization and physical properties of these optically active PEIs are reported. Copyright © 2005 John Wiley & Sons, Ltd.
How ischaemic preconditioning protects small liver grafts
Authors: Franco‐Gou R , Roselló‐Catafau J , Casillas‐Ramirez A , Massip‐Salcedo M , Rimola A , Calvo N , Bartrons R , Peralta C 
Published: November 2005

AbstractInterleukin‐1 (IL‐1) and transforming growth factor‐β (TGFβ) are key inhibitors of hepatocyte proliferation after hepatectomy. IL‐1 inhibition by heat shock proteins (HSPs) has been reported in inflammatory processes. A recent study indicated the benefits of ischaemic preconditioning in reduced‐size orthotopic liver transplantation (ROLT). The present study examined: (a) the effect of ischaemic preconditioning on IL‐1 and TGFβ in ROLT; (b) whether preconditioning protects small liver grafts through HSP induction; and (c) whether the potential benefits of preconditioning on HSP is related to IL‐1 inhibition. Our results, obtained with an IL‐1 receptor antagonist, indicated the injurious effects of IL‐1 in ischaemia‐reperfusion (I/R) injury and established a relationship between IL‐1 and growth factors. Thus, IL‐1 reduced hepatocyte growth factor (HGF) and promoted TGFβ release, thus contributing to the impaired liver regeneration associated with ROLT. Preconditioning inhibited IL‐1 through nitric oxide (NO), thereby protecting against the injurious effects of IL‐1. In addition, by another pathway independent of NO, preconditioning induced HSP70 and haem‐oxygenase‐1 (HO‐1). HO‐1 protected against I/R injury and liver regeneration, whereas the benefits resulting from HSP70 were mainly related to hepatocyte proliferation. These results suggest a mechanism that explains the effectiveness of preconditioning in ROLT. They suggest, too, that other strategies, in addition to preconditioning, that modulate IL‐1 and/or HSPs could be considered in clinical situations requiring liver regeneration such as small liver grafts. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Synthesis and optical and electrochemical properties of new π‐conjugated 1,3,5‐triazine‐containing polymers
Authors: Ren Shijie , Fang Qiang , Yu Feng , Bu Dongsheng 
Published: November 2005

AbstractTwo new π‐conjugated polymers containing 1,3,5‐triazine units in the main chain, Pa and Pb, are reported. Pa and Pb (R = H and OCH3, respectively) showed blue photoluminescence emissions with quantum yields of more than 50% in toluene. In the solid state, Pa and Pb showed photoluminescence maximum emission peaks at 479 and 475 nm, respectively. Electrochemically, Pa and Pb showed good stability and reversibility under repeated electrochemical reduction. The polymers had glass‐transition temperatures higher than 90 °C and had 5 wt % loss temperatures higher than 400 °C. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6554–6561, 2005
Novel fluorinated stabilizers for ring‐opening polymerization in supercritical carbon dioxide
Authors: Bratton Daniel , Brown Malcolm , Howdle Steven M. 
Published: November 2005

AbstractRing‐opening polymerization (ROP) in supercritical carbon dioxide (scCO2) has been the subject of much recent interest, although few publications describe the development of stabilizers to produce biodegradable particles of poly(L‐lactide) (PLLA) and polyglycolide (PGA). Here we describe the synthesis of a series of novel fluorinated diblock copolymers by the acid‐catalyzed esterification of well‐defined blocks of polycaprolactone (PCL) with Krytox 157FSL, a carboxylic acid terminated perfluoropolyether. These diblock copolymers were then tested as stabilizers in the ROP of glycolide and L‐lactide, or a mixture of the two, in scCO2, and this resulted in the corresponding homopolymers or random copolymers. In the absence of stabilizers, only aggregated solids were formed. When the reaction was repeated with a stabilizer, PGA and PLLA were obtained as discrete microparticles. The stabilizer efficiency increased as the length of the polymer‐philic PCL block increased. One optimized stabilizer worked at loadings as low as 3% (w/w) with respect to the monomer, demonstrating these to be extremely effective stabilizers. It was found that to produce microparticles with this process, the product polymers must be semicrystalline; amorphous polymers, such as poly(lactide‐co‐glycolide), are plasticized by scCO2 and yield only aggregated solids rather than discrete particles. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6573–6585, 2005
Preparation of a reflective‐type electrochromic device based on monodisperse, micrometer‐size‐range polymeric microspheres and viologen pendants
Authors: Ryu Jee‐Hyun , Shin Dong‐Oh , Suh Kyung‐Do 
Published: November 2005

AbstractA reflective electrochromic device (ECD) based on polymeric microspheres was proposed, and its feasibility for a display was investigated. The viologen moiety was introduced onto the surface of chloro‐functionalized polymeric microspheres via refluxing in toluene. The existence of the viologen pendants was confirmed with X‐ray photoelectron spectroscopy, and their redox reactions were examined with cyclic voltammetry. The ECD had an inherent white background without an applied potential because the micrometer size range of the substrate particles scattered the light, whereas a deep violet color appeared when 3.0 V was applied to the cell. This color change could have been caused by the reduction of viologen pendants on the surface of the polymeric microspheres. The reflectance values of the ECD were observed with a spectrophotometer, and the response times and cyclic stability of the ECD, depending on the potential, were also examined. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6562–6572, 2005
Cooperativity of conventional and unconventional hydrogen bonds involving imidazole
Authors: Kar Tapas , Scheiner Steve 
Published: November 2005

AbstractCorrelated ab initio calculations are used to investigate the cooperativity of H‐bonds between imidazole and a pair of water molecules. H‐bonds comprise not only the conventional NH … O and OH … N types, but also CH … O and OH … φ (wherein a proton is donated to the delocalized π cloud lying above the aromatic ring). Conventional and OH … φ H‐bonds obey the normal principles of cooperativity, wherein these bonds are strengthened when a central molecule serves simultaneously as both proton donor and acceptor. In contrast, CH … O bonds do not appear to be amenable to such positive cooperativity. When placed in a polarizable medium, all H‐bonds weaken as the dielectric constant of the solvent grows. The qualitative aspects of the cooperativity are not affected by the medium, although some weakening is observed. Calculations also consider the effects of cooperativity on other aspects of the complexes, including the intermolecular distance, the effect on the covalent X‐H bond length, and IR and NMR spectral data. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Ab initio studies on excited state intramolecular electron transfer in 4‐amino‐N‐methylphthalimide and 3‐amino‐N‐methylphthalimide
Authors: Sen Kakali , Basu Samita , Bhattacharyya Dhananjay 
Published: November 2005

AbstractThe molecules 4‐amino‐N‐methylphthalimide (4AMP) and 3‐amino‐N‐methylphthalimide (3AMP) are bichromophoric compounds composed of both electron donors and acceptor groups. They undergo intramolecular electron transfer (ET), and these types of compounds are frequently used to probe microenvironments in proteins, micelles, membranes, polymer, surfaces, etc. Ab initio calculations using restricted Hartree–Fock (RHF), Møller–Plesset second‐order perturbation theory (MP2) and the multi‐configurational self‐consistent field (MCSCF) methods with the 6‐31G** basis set have been performed to characterize the intermediates of the ET process. Analysis of geometrical and electronic parameters, e.g., changes in bond lengths, angles, dihedrals, and charge density, generally used to predict the ET pathway, is not always sufficient to understand the through‐bond intramolecular charge‐transfer (ICT) process. Hence we have attempted to support the predicted ET pathway in a very unique way by analyzing normal modes of vibrations for molecules in both the ground and excited states. Our results predict a planar ICT model that exhibits a conformational change of the amino nitrogen from nearly sp3 in the ground state to approximately sp2 type in the ICT state. A through‐bond ET occurs from the amino group of both molecules to the proximal carbonyl group in 4AMP and to the distant carbonyl group in 3AMP. Besides ET, the proximal carbonyl group in 3AMP also takes part in hydrogen bonding with the same amino group especially in excited state, which may also contribute toward ET. Such a hydrogen bond, which demands a planar amino group, is not observed in ground‐state 3AMP. These results indicate that nonplanar amino group geometry in the vicinity of a conjugated system is favored, rather than the conventional planar geometry, even in the presence of a suitable hydrogen bond acceptor. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Stable hydrogen and oxygen isotope ratios of bottled waters of the world
Authors: Bowen Gabriel J. , Winter David A. , Spero Howard J. , Zierenberg Robert A. , Reeder Mathew D. , Cerling Thure E. , Ehleringer James R. 
Published: November 2005

AbstractBottled and packaged waters are an increasingly significant component of the human diet. These products are regulated at the regional, national, and international levels, and determining the authenticity of marketing and labeling claims represents a challenge to regulatory agencies. Here, we present a dataset of stable isotope ratios for bottled waters sampled worldwide, and consider potential applications of such data for regulatory, forensic and geochemical standardization applications. The hydrogen and oxygen isotope ratios of 234 samples of bottled water range from −147‰ to +15‰ and from −19.1‰ to +3.0‰, respectively. These values fall within and span most of the normal range for meteoric waters, indicating that these commercially available products represent a source of waters for use as laboratory working standards in applications requiring standardization over a large range of isotope ratios. The measured values of bottled water samples cluster along the global meteoric water line, suggesting that bottled water isotope ratios preserve information about the water sources from which they were derived. Using the dataset, we demonstrate how bottled water isotope ratios provide evidence for substantial evaporative enrichment of water sources prior to bottling and for the marketing of waters derived from mountain and lowland sources under the same name. Comparison of bottled water isotope ratios with natural environmental water isotope ratios demonstrates that on average the isotopic composition of bottled water tends to be similar to the composition of naturally available local water sources, suggesting that in many cases bottled water need not be considered as an isotopically distinct component of the human diet. Our findings suggest that stable isotope ratios of bottled water have the power to distinguish ultimate (e.g., recharge) and proximal (e.g., reservoir) sources of bottled water and constitute a potential tool for use in the regulatory monitoring of water products. Copyright © 2005 John Wiley & Sons, Ltd.
Development and validation of a capillary high‐performance liquid chromatography/electrospray tandem mass spectrometric method for the quantification of bisphenol A in air samples
Authors: Sabatini Laura , Barbieri Anna , Violante Francesco Saverio 
Published: November 2005

AbstractBisphenol A (BPA) is a toxic industrial chemical that affects the endocrine system even at low concentrations. A new method, based on capillary high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI‐MS/MS) analysis, has been developed to determine BPA in atmospheric samples. The method involves collection of air samples (typically 2 m3) on glass fiber filters, with ultrasonic extraction and sample concentration under vacuum before analysis. HPLC analysis was performed isocratically at a flow rate of 10 µL min−1 using a capillary reversed‐phase column and MS/MS analysis in negative ion multiple reaction monitoring (MRM) mode, using BPA‐d16 as internal standard. The present method provides linear response in the range 0.007–3.5 µg/filter (R2 > 0.999) and is characterized by high accuracy (mean bias 2%) and good reproducibility (mean RSD 5%). High sensitivity (LOD = 2 ng/m3 based on 2 m3 of air collected), specificity, and speed of the analysis make the present method suitable for routine determination of BPA in the atmosphere, both for ambient and personnel monitoring. Copyright © 2005 John Wiley & Sons, Ltd.
Characterization and quantification of soy isoflavone metabolites in serum of renal transplanted patients by high‐performance liquid chromatography/electrospray ionization mass spectrometry
Authors: Locati Daniela , Morandi Sheila , Cupisti Adamasco , Ghiadoni Lorenzo , Arnoldi Anna 
Published: November 2005

AbstractDuring a dietary intervention study on 16 renal transplanted patients, in which 25 g/day of animal proteins were replaced with 25 g of soy proteins, the metabolic profile of soy isoflavones in serum was characterized. This paper describes a reliable and fast liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS) method, in negative ion mode, allowing the characterization and simultaneous quantification of several soy isoflavone metabolites. Six metabolites were identified and quantified: daidzein ([M–H]− at m/z 252.8), dihydrodaidzein (DHD, [M–H]− at m/z 254.8), equol ([M–H]− at m/z 240.9), O‐desmethylangolensin (O‐DMA, [M–H]− at m/z 256.8), genistein ([M–H]− at m/z 268.8), and dihydrogenistein (DHG, ([M–H+]− at m/z 270.8). Quantification was assessed using two deuterated internal standards, D3‐daidzein and D4‐genistein. This method permitted a limit of quantification (LOQ, S/N = 10) and a limit of detection (LOD, S/N = 3) of 0.05 µM and 0.005 µM for all analytes, except for genistein, where the LOQ and LOD were 0.005 µM and 0.001 µM, respectively. The linearity ranges were from 0.005 to 1.5 µM for genistein, from 0.05 to 1.5 µM for DHG, and from 0.05 to 0.7 µM for the other metabolites. The relative standard deviations (RSDs) were between 0.19% and 13.9% at the LOQ concentration for all metabolites, and between 0.6% and 4.8% at the maximum concentration. On the basis of the results obtained in the dietary intervention study, it was possible to split the patients into five groups characterized by different metabolic pathways. Copyright © 2005 John Wiley & Sons, Ltd.
Energetics and efficiencies of collision‐induced dissociation achieved during the mass acquisition scan in a quadrupole ion trap
Authors: Jackson Glen P. , Hyland Jennifer J. , Laskay Ünige A. 
Published: November 2005

AbstractUsing n‐butylbenzene as a test molecule, evidence is provided that fast, efficient or highly energetic collision‐induced dissociation (CID) can be achieved during the mass acquisition ramp of a commercially available quadrupole ion trap (QIT) mass spectrometer. The method of excitation is very similar to axial modulation for mass range extension except that lower amplitude waveforms are used to excite the precursor ions within the trap instead of ejecting them from the trap. ITSIM simulations verify that fast kinetic excitation followed by kinetic‐to‐internal energy transfer occurs on the rapid time‐scale required for the recapture and mass analysis of product ions during the mass acquisition ramp. CID efficiencies larger than 50% can be obtained using this new approach and ratios of Th 91/92 of n‐butylbenzene fragment ions as large as 9 are possible, albeit at significantly reduced efficiencies. These very large ratios indicate an internal energy above 7 eV for the precursor ions indicating that fragmentation of larger ions could also be possible using this new approach. The main benefits of the new method are that no extra time is required for fragmentation or cooling and that on‐resonance conditions are guaranteed because the ions' secular frequencies are swept through the fixed frequency of excitation. Also presented are the effects of experimental variables such as excitation frequency, excitation amplitude and scan rate on the CID efficiencies and energetics. Copyright © 2005 John Wiley & Sons, Ltd.
Confidence interval construction for proportion difference in small‐sample paired studies
Authors: Tang Man‐Lai , Tang Nian‐Sheng , Chan Ivan S. F. 
Published: November 2005

AbstractPaired dichotomous data may arise in clinical trials such as pre‐/post‐test comparison studies and equivalence trials. Reporting parameter estimates (e.g. odds ratio, rate difference and rate ratio) along with their associated confidence interval estimates becomes a necessity in many medical journals. Various asymptotic confidence interval estimators have long been developed for differences in correlated binary proportions. Nevertheless, the performance of these asymptotic methods may have poor coverage properties in small samples. In this article, we investigate several alternative confidence interval estimators for the difference between binomial proportions based on small‐sample paired data. Specifically, we consider exact and approximate unconditional confidence intervals for rate difference via inverting a score test. The exact unconditional confidence interval guarantees the coverage probability, and it is recommended if strict control of coverage probability is required. However, the exact method tends to be overly conservative and computationally demanding. Our empirical results show that the approximate unconditional score confidence interval estimators based on inverting the score test demonstrate reasonably good coverage properties even in small‐sample designs, and yet they are relatively easy to implement computationally. We illustrate the methods using real examples from a pain management study and a cancer study. Copyright © 2005 John Wiley & Sons, Ltd.
Provably-correct hardware compilation tools based on pass separation techniques
Authors: McKeever Steve , Luk Wayne 
Published: November 2005

Abstract
This paper presents a framework for verifying compilation tools for parametrised hardware designs with placement information. The framework involves Pebble, a simple declarative language based on Structural VHDL which supports the use of placement information to guide circuit layout; such information often leads to efficient designs that are particularly important for hardware libraries. Relative placement information enables control of circuit layout at a higher level of abstraction than placement information in the form of explicit coordinates. An approach based on pass separation techniques is adopted for specifying and verifying two Pebble abstraction mechanisms: a flattening procedure and a relative placement method. For the flattening procedure, which takes a set of parametrised blocks and unfolds the circuit description into a netlist, we provide semantic descriptions of both the hierarchical and the flattened Pebble languages to prove its functional correctness. For the relative placement method, we specify the compilation procedure from Pebble programs with relative placement information to Pebble programs with explicit coordinate expressions, often in the form of symbolic placement constraints. This compilation procedure can be used in conjunction with partial evaluation to optimise the size and speed of parametrised circuit descriptions using relative placement, without flattening the original hierarchical descriptions. Our approach has been used for optimising a pattern matcher design, which results in a 33% reduction in resource usage. For DES encryption, our method can reduce the size of a DES design by 60%.