bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non‐empirical calculations of NMR indirect carbon–carbon coupling constants. Part 4: Bicycloalkanes
Authors: Krivdin Leonid B. 
Published: May 2003

AbstractA systematic study of the one‐bond and long‐range J(C,C), J(C,H) and J(H,H) in the series of nine bicycloalkanes was performed at the SOPPA level with special emphasis on the coupling transmission mechanisms at bridgeheads. Many unknown couplings were predicted with high reliability. Further refinement of SOPPA computational scheme adjusted for better performance was carried out using bicyclo[1.1.1]pentane as a benchmark to investigate the influence of geometry, basis set and electronic correlation. The calculations performed demonstrated that classical ab initio SOPPA applied with the locally dense Dunning's sets augmented with inner core s‐functions used for coupled carbons and Sauer's sets augmented with tight s‐functions used for coupled hydrogens performs perfectly well in reproducing experimental values of different types of coupling constants (the estimated reliability is ca 1–2 Hz) in relatively large organic molecules of up to 11 carbon atoms. Additive coupling increments were derived for J(C,C), J(C,H) and J(H,H) based on the calculated values of coupling constants within SOPPA in the model bicycloalkanes, in reasonably good agreement with the known values obtained earlier on pure empirical grounds. Most of the bridgehead couplings in all but one bicycloalkane appeared to be essentially additive within ca 2–3 Hz while bicyclo[1.1.1]pentane demonstrated dramatic non‐additivity of −14.5 Hz for J(C,C), +16.6 Hz for J(H,H) and −5.5 Hz for J(C,H), in line with previous findings. Non‐additivity effects in the latter compound established at the SOPPA level should be attributed to the through‐space non‐bonded interactions at bridgeheads due to the essential overlapping of the bridgehead rear lobes which provides an additional and effective non‐bonding coupling path for the bridgehead carbons and their protons in the bicyclopentane framework. Copyright © 2003 John Wiley & Sons, Ltd.
A new scheme for imposing a minimum length scale in topology optimization
Authors: Poulsen Thomas A. 
Published: May 2003

AbstractA new scheme for imposing a minimum length scale in topology optimization is presented. It guarantees the existence of an optimal design for a large class of topology optimization problems of practical interest. It is formulated as one constraint that is computationally cheap and for which sensitivities are also cheap to compute. The constraint value is ideally zero, but it can be relaxed to a positive value. The effect of the method is illustrated in topology optimization for minimum compliance and design of compliant mechanisms. Notably, the method produces compliant mechanisms with distributed flexibility, something that has previously been difficult to obtain using topology optimization for the design of compliant mechanisms. The term ‘MOLE method’ is suggested for the method. Copyright © 2003 John Wiley & Sons, Ltd.
Convergence of the fixed point theorem with random parameters
Authors: Poirion F. 
Published: May 2003

AbstractSolving stochastic non‐linear dynamical problems represents a formidable task which, in many cases, can be achieved solely through numerical simulation techniques. This is true for high dimensional as well as low dimensional problems. One method to deal with the non‐linearity is to use the fixed point theorem which gives the convergence conditions of the iterative scheme towards the equilibrium point of the equation. In this paper we look at the particular case where the equilibrium equation depends on a random variable. This case arises for instance in the study of coupled non‐linear dynamical systems when structural uncertainties are introduced in the dynamical systems. We give almost sure and L p convergence conditions for the simulation iterative scheme. Copyright © 2003 John Wiley & Sons, Ltd.
An indirect elastodynamic boundary element method with analytic bases
Authors: Shen Shih‐yu 
Published: May 2003

AbstractAn indirect time‐domain boundary element method (BEM) is presented here for the treatment of 2D elastodynamic problems. The approximated solution in this method is formulated as a linear combination of a set of particular solutions, which are called bases. The displacement and stress fields of a basis are analytically derived by means of solving Lame's displacement potentials. A semi‐collocation method is proposed to be the time‐stepping algorithm. This method is equivalent to a displacement discontinuity method with piecewise linear discontinuities in both space and time. The resulting time‐stepping scheme is explicit. The BEM is implemented to solve three numerical examples, Lamb's problem, half‐plane with a buried crack and Selberg's problem. Though Lamb's problem is considered a difficult problem for numerical methods, the current numerical results for the surface displacements show accurately the characteristics of the Rayleigh wave. This method is efficient and accurate. Copyright © 2003 John Wiley & Sons, Ltd.
Worst‐case design in head impact crashworthiness optimization
Authors: Craig K. J. , Stander Nielen , Balasubramanyam Suri 
Published: May 2003

AbstractThis paper describes the solution of a worst‐case design optimization problem of head impact in automotive design. The worst‐case design process uses an optimization algorithm that can locate saddlepoints: points in the design space where the objective function is maximized with respect to some design variables (worst case) while it is minimized with respect to other design variables simultaneously. The worst‐case design methodology is first tested using two analytic functions. Both functions contain saddlepoints, while the second one also has a random analytic noise component and an integer variable. Thereafter, the methodology is applied to the worst‐case design of a crashworthiness head impact problem. The head impact problem contains both numerical noise and an integer variable. For the first analytical case, the effect of separability of the maximization and minimization variables is investigated by rotating the design variable axes. For the second analytical case, analytical noise in the form of a modified Griewank function and an integer variable is added. For the head impact problem, cases are presented where maximization and minimization are first performed separately, and then in a combined fashion to locate the saddle point. The case studies illustrate the power of this approach in the automotive occupant safety design field. Copyright © 2003 John Wiley & Sons, Ltd.
A comparison of modelling methods for polydispersed wet‐steam flow
Authors: White A. J. 
Published: May 2003

AbstractSpontaneous nucleation of water droplets in moist air or steam may result in droplet spectra which are complex in shape and which span a broad range of sizes. This is particularly true if the flow is transonic or supersonic with shock waves present, or if an already droplet‐laden flow re‐expands to give secondary or tertiary nucleations. Computation of such flows requires careful modelling of the size distributions if two‐phase behaviour is to be accurately predicted. In this paper, three methods are presented for treating size distributions and growth of the liquid phase in condensing steam: a mixed Eulerian–Lagrangian method, a fully Eulerian method, and a method based on moments of the droplet spectra. These are compared by computing condensing flow within a one‐dimensional supersonic nozzle under conditions that yield very different types of size spectra. Copyright © 2003 John Wiley & Sons, Ltd.
Symmetric‐Galerkin BEM simulation of fracture with frictional contact
Authors: Phan A.‐V. , Napier J. A. L. , Gray L. J. , Kaplan T. 
Published: May 2003

AbstractA symmetric‐Galerkin boundary element framework for fracture analysis with frictional contact (crack friction) on the crack surfaces is presented. The algorithm employs a continuous interpolation on the crack surface (utilizing quadratic boundary elements) and enables the determination of two important quantities for the problem, namely the local normal tractions and sliding displacements on the crack surfaces. An effective iterative scheme for solving this non‐linear boundary value problem is proposed. The results of test examples are compared with available analytical solutions or with those obtained from the displacement discontinuity method (DDM) using linear elements and internal collocation. The results demonstrate that the method works well for difficult kinked/junction crack problems. Copyright © 2003 John Wiley & Sons, Ltd.
Autonomous decentralized finite element method and its applications
Authors: Honma Toshio , Tosaka Nobuyoshi 
Published: May 2003

AbstractIn this paper, a new solution procedure using the finite element technique in order to solve problems of structure analysis is proposed. This procedure is called the autonomous decentralized finite element method because it is based on the characteristic autonomy and decentralization in life or biological systems (life‐like approach). The fundamental approach is developed according to an idea of cellular automata manipulation by the new neighbourhood model. The finite element method with an algorithm of the relaxation method is adopted as the solution procedure in this approach. The proposed procedure demonstrates that it is a powerful means of numerical analysis for many kinds of structural problems that are structural morphogenesis, structural optimization and structural inverse problems. Our procedure is applied to numerical analysis of three simple plane models: (1) The structural shape analysis problem for the prescribed displacement mode of a truss structure, (2) An adaptive structure remodelling problem on an elastic continuum, (3) An identification problem of thermal conductivity on a continuum. The effectiveness and validity of our idea are shown from their numerical results. Copyright © 2003 John Wiley & Sons, Ltd.
Mixed finite element method for saturated poroelastoplastic media at large strains
Authors: Li Xikui , Liu Zejia , Lewis R. W. , Suzuki Kiichi 
Published: May 2003

AbstractA mixed finite element for hydro‐dynamic analysis in saturated porous media in the frame of the Biot theory is proposed. Displacements, effective stresses, strains for the solid phase and pressure, pressure gradients, and Darcy velocities for the fluid phase are interpolated as independent variables. The weak form of the governing equations of coupled hydro‐dynamic problems in saturated porous media within the element are given on the basis of the Hu–Washizu three‐field variational principle. In light of the stabilized one point quadrature super‐convergent element developed in solid continuum, the interpolation approximation modes for the primary unknowns and their spatial derivatives of the solid and the fluid phases within the element are assumed independently. The proposed mixed finite element formulation is derived. The non‐linear version of the element formulation is further derived with particular consideration of pressure‐dependent non‐associated plasticity. The return mapping algorithm for the integration of the rate constitutive equation, the consistent elastoplastic tangent modulus matrix and the element tangent stiffness matrix are developed. For geometrical non‐linearity, the co‐rotational formulation approach is used. Numerical results demonstrate the capability and the performance of the proposed element in modelling progressive failure characterized by strain localization due to strain softening in poroelastoplastic media subjected to dynamic loading at large strain. Copyright © 2003 John Wiley & Sons, Ltd.
Qualitative determination of false‐positive effects in the acetylcholinesterase assay using thin layer chromatography
Authors: Rhee In K. , van Rijn Richard M. , Verpoorte Robert 
Published: May 2003

AbstractA method has been developed to determine the false‐positive effects on acetylcholinesterase inhibition in the TLC assay based on Ellman's method. Various aldehydes and amines have been tested in order to determine whether the observed inhibition is due to a true enzyme inhibition or due to the inhibition of the reaction between thiocholine and 5,5′‐dithiobis‐(2‐nitrobenzoic acid). 4‐Dimethylaminobenzaldehyde, 3‐ethoxy‐4‐hydroxybenzaldehyde, diethylamine, triethylamine, triethanolamine and tyramine showed real enzyme inhibition, although their activity was about 103 times lower than that shown by galanthamine. Heptanal, decanal, cinnamaldehyde, anisaldehyde, benzaldehyde, hexylamine and tryptamine appeared to show a non‐specific chemical inhibition. By checking this chemical inhibition on the TLC assay, the true enzyme inhibition could be distinguished from the false‐positive chemical inhibition observed in the toluene extract of Nerine bowdenii in the course of isolation of active compounds. Copyright © 2003 John Wiley & Sons, Ltd.
Determination of diterpenoid triepoxides in Tripterygium wilfordii by micellar electrokinetic capillary chromatography
Authors: Song Xiurong , Yang Gengliang , Zhao Jingxiang , Chen Yi , Sun Hanwen , Zhang Hongyi 
Published: May 2003

AbstractA micellar electrokinetic capillary chromatographic (MEKC) method has been established for the identification and determination of diterpenoid triepoxides in the Chinese herb Tripterygium wilfordii Hook F. and its preparations. Studies of the influence of boric acid and borax buffer concentration and pH, and of sodium dodecylsulphate (SDS) concentration have been carried out, and the optimum separation for the triepoxides was achieved using 20 mM boric acid and 10 mM borax with 20 mM SDS as the running buffer. MEKC was found to exhibit good accuracy, precision and repeatability. The sensitivity of the assay was sufficient to monitor the three active components in T. wilfordii and its preparations. Copyright © 2003 John Wiley & Sons, Ltd.
Determining acetylcholinesterase inhibitory activity in plant extracts using a fluorimetric flow assay
Authors: Rhee In Kyung , Appels Natalie , Luijendijk Teus , Irth Hubertus , Verpoorte Robert 
Published: May 2003

AbstractA fluorometric assay for acetylcholinesterase inhibitory activity was developed in a flow system using the fluorogenic substrate 7‐acetoxy‐1‐methyl quinolinium iodide which is hydrolysed to the highly fluorescent 7‐hydroxy‐1‐methyl quinolinium iodide. The detection limit of galanthamine is 0.5 µM, which is about 20 times more sensitive than in the colorimetric flow assay. In the presence of 30% methanol or of 5% acetonitrile, about 70% of the enzyme activity could still be detected. Various plant extracts have been screened using the described system including bulbs of Galanthus nivalis, Eucharis amazonica (E. × grandiflora), Crinum powelli and Nerine bowdenii (all members of the Amaryllidaceae), which showed strong AchE inhibitory activity. Copyright © 2003 John Wiley & Sons, Ltd.
Purification of anthocyanins from species of Banksia and Acacia using high‐voltage paper electrophoresis
Authors: Asenstorfer Robert E. , Morgan Anne L. , Hayasaka Yoji , Sedgley Margaret , Jones Graham P. 
Published: May 2003

AbstractA new method has been developed for the isolation and rapid identification of anthocyanins from two floricultural crops based on the use of high‐voltage paper electrophoresis with bisulphite buffer. Using this method, anthocyanin pigments were successfully purified as their negatively charged bisulphite‐addition compounds from crude extracts of plant tissue. In conjunction with liquid chromatography–electrospray mass spectrometry, the method enabled the anthocyanins from the flowers of two Banksia species and the leaves of two Acacia species to be identified. The Banksia flowers contained both cyanidin and peonidin‐based pigments, while the Acacia leaves contained cyanidin and delphinidin derivatives. Copyright © 2003 John Wiley & Sons, Ltd.
Identification and quantification of methyl jasmonate in leaf volatiles of Arabidopsis thaliana using solid‐phase microextraction in combination with gas chromatography and mass spectrometry
Authors: Meyer Riaan , Rautenbach George F. , Dubery Ian A. 
Published: May 2003

AbstractStatic headspace sampling with solid‐phase microextraction has been used in combination with GC‐FID and GC‐MS for the specific enrichment, identification and quantification of volatile methyl jasmonate secreted by wounded leaves of Arabidopsis thaliana. The microsample method of analysis was found to be precise, accurate, sensitive and rapid. The detection limit of the procedure is 1.5 ppb (∼1.3 ng) per injection, which is of adequate sensitivity to detect the natural baseline levels of methyl jasmonate (∼10–100 ng/g) present in plant tissues. The method can be applied to most plants, requires a minimum of sample material, and shows the additional advantage that it is suitable for automation and could thus be used for high‐throughput screening. Copyright © 2003 John Wiley & Sons, Ltd.
Determination of manganese (II) in some medicinal plants and their decoctions by a kinetic spectrophotometric method
Authors: Mutaftchiev Konstantin , Tzachev Kamen 
Published: May 2003

AbstractThe catalytic effect of manganese (II) on the oxidation of the azo dye tropaeolin 00 with potassium periodate in the presence of 1,10‐phenanthroline was investigated. The reaction was followed spectrophotometrically by measuring the decrease in the absorbance of the azo dye at 445 nm. Under the optimum analytical conditions, manganese (II) in the range 0.05–2.5 ng/mL could be determined by the fixed‐time method with a detection limit of 0.02 ng/mL. The developed method is highly sensitive, selective and simple, and was applied successfully to analyse decoctions of some medicinal plants for trace amounts of total manganese (II) and free manganese (II) ions without separation. Copyright © 2003 John Wiley & Sons, Ltd.
Electrospray mass spectrometric decomposition of some glucuronic acid‐containing flavonoid diglycosides
Authors: Frański Rafał , Eitner Krystian , Sikorska Maria , Matławska Irena , Stobiecki Maciej 
Published: May 2003

AbstractMass spectrometric fragmentation patterns of herbacetin 3‐O‐glucopyranoside‐8‐O‐glucuronopyranoside (1), gossypetin 3‐O‐glucopyranoside‐8‐O‐glucuronopyranoside (2) and takakin 7‐O‐glucopyranoside‐8‐O‐glucuronopyranoside (3) were elucidated from mass spectra obtained with electrospray ionisation. The usefulness of the fragmentation patterns observed in the positive and negative mode for structural elucidation of the studied compounds is discussed. The fragmentation of 3 was substantially different from 1 and 2, especially in the negative mode. In order to explain these differences, theoretical calculations were performed. Copyright © 2003 John Wiley & Sons, Ltd.
‘Are you being converted to partial…?’
Authors: Wales JK 
Published: May 2003

AbstractA new system of partial booking for outpatients is being introduced in the NHS, which will include hospital diabetic clinics. What is the likely impact on the care of patients? Some believe it will make the service more user friendly; others think it will be a long‐term disaster. What do you think? Let us know. Copyright © 2003 John Wiley & Sons, Ltd.
Subcutaneous insulin without a needle: a pilot evaluation of the J‐Tip® delivery system
Authors: Stephens JW , Butteriss D , Payne N , Barker SGE , Hurel SJ 
Published: May 2003

AbstractThe J‐Tip® device has been approved for the delivery of liquid therapeutic agents into the subcutaneous space. Our aim in this pilot study was to evaluate the J‐Tip® as an alternative method of insulin delivery.Ten patients with stable type 1 diabetes, treated with a multiple dosing regimen, attended on each of two days. On day one, each self‐administered their morning dose of Actrapid with their usual injection pen, and on day two with the J‐Tip®. Blood samples for plasma glucose and insulin measurements were collected over a four‐hour period. All subjects completed an evaluation questionnaire.No significant difference was observed in mean plasma glucose or insulin at any of the sampling times using the two different methods of insulin delivery. Only one subject reported soreness, or bruising, at the delivery site.This pilot study shows that the J‐Tip® needle‐free delivery system is an effective and alternative method to administer subcutaneous insulin. Copyright © 2003 John Wiley & Sons, Ltd.
Implementation of an effective outpatient intensive education programme for patients with type 1 diabetes
Authors: Everett J , Jenkins E , Kerr D , Cavan DA 
Published: May 2003

AbstractEducation for our local clinic population with type 1 diabetes was unsatisfactory with an HbA1c audit revealing suboptimal diabetes control. Clinical practice was changed to offer structured, group education to newly diagnosed and established patients with type 1 diabetes. Since 1999, 58 patients, 28 male, mean age 32 (range 18–65) years, mean duration of diabetes 2 (range 0.6–34) years have completed the programme.HbA1c (mean±SE) fell from 8.9±0.2% to 8.4±0.2% (p<0.001) at three months, was maintained at six months, 8.6%±0.3 at 12 months and 8.3%±0.5 at 24 months. These results were dependent upon the duration of diabetes and the HbA1c level at entry. Mean diabetes management skills, as measured by the Ipswich Questionnaire, rose from 135 (95% CI 126–138) to 151 (95% CI 147–155) at three months (p<0.0001, paired t test) and this was maintained to 12 months. Food knowledge improved in terms of recognising and counting carbohydrates.In conclusion, we have demonstrated that an intensive education programme for type 1 diabetes can be implemented, audited and resourced within a clinic population. Copyright © 2003 John Wiley & Sons, Ltd.
Efficacy of triple combination oral hypoglycaemic therapy using rosiglitazone, metformin and sulphonylurea in lowering HbA1c
Authors: Byrne J , Garg S , Vaidya A , Rajbhandari SM , Wallis SC 
Published: May 2003

AbstractThiazolidinediones are a new class of oral hypoglycaemic agents, which have been reviewed by the National Institute for Clinical Excellence (NICE) and guidelines published. There is ambiguity in the NICE guidelines regarding the use of the triple combination of sulphonylurea, metformin and thiazolidinedione to treat type 2 diabetes. However, in our retrospective audit we found that triple therapy was used in 52% of patients treated with thiazolidinediones. When we analysed the effect of triple therapy we found that it significantly (p<0.05) reduced HbA1c from 9.6% (±1.5%) to 8.4% (±1.1%). Further prospective studies will be needed to confirm this. Copyright © 2003 John Wiley & Sons, Ltd. Copyright © 2003 John Wiley & Sons, Ltd.
Homopolymers and copolymers of acrylates and methacrylates of homoterpenylmethyl carbinol and α‐campholenol
Authors: Liepins R. , Marvel C. S. 
Published: May 2003

AbstractAcrylates and methacrylates of homoterpenylmethyl carbinol and α‐campholenol were homopolymerized. Copolymers with each other and acrylonitrile were studied. Terpolymers of the acrylate of homoterpenylmethyl carbinol and the acrylate of α‐campholenol with butadiene and styrene or acrylonitrile were also prepared. The lactone ring in the homopolymer of methacrylate of homoterpenylmethyl carbinol was opened up under basic conditions at room temperature, yielding a water‐soluble polymer. Films of this polymer were cast from a water solution. The acrylate of homoterpenylmethyl carbinol gave a high molecular weight copolymer with acrylonitrile which could be molded into a transparent, extremely tough, film. The terpolymers of the acrylate of homoterpenylmethyl carbinol with butadiene and styrene or acrylonitrile were obtained in high yield and could be molded into strong, rubbery films. Several polymers were epoxidized and cured with p‐phenylenediamine.