bluuebunny/crossref_metadata_2025 huggingface dataset:
Rediscovering the imagination: investigating active and passive visitor experience in the 21st century
Authors: Voase Richard
Published: August 2002

The experiential nature of visits to cultural and heritage attractions is theorised. Contemporary discourses posit the emergence of a ‘thoughtful’ consumer and a paradoxical ‘dumbing‐down’ of culture. The discursive links between ‘active’ consumption and thought/learning, and of ‘passive’ consumption with dumbness/fun, are argued to be fallacious; the meanings of ‘active’ and ‘passive’ are in need of re‐evaluation. ‘Dumbing‐down’ is suggested to be a discursive term for the lowering of the threshold of engagement by cultural producers, implying neither ‘dumb’ content nor ‘dumb’ consumers. Postmodernisation has eroded the protocols governing access to culture, producing two simultaneous effects: the augmentation of opportunities for ‘thoughtful’ engagement, and increasing commodification giving rise to a ‘smart’ consumer with an initial focus on transaction. A popular threshold of engagement is a recommended and rational strategy for attracting and engaging both ‘thoughtful’ and ‘smart’ consumers. Copyright © 2002 John Wiley & Sons, Ltd.
A situational analysis on how salespeople experience and cope with shame and embarrassment
Authors: Verbeke Willem , Bagozzi Richard P.
Published: August 2002

The goal of this article is to explore the role that shame and embarrassment play within an organization boundary‐spanning context. For a sample of 458 salespeople selling financial services, measures are developed and hypotheses are tested concerning the effects of shame and embarrassment. The results suggest that the tendency to experience shame and embarrassment in personal selling leads to protective reactions (e.g., avoidance behaviors), and these, in turn, negatively impact performance (e.g., sales volume and quality of sales interaction). Hypotheses are tested on fitting and validation samples, both for salespeople focusing on prospecting tasks and salespeople focusing on relationship building. © 2002 Wiley Periodicals, Inc.
Toward understanding the young consumer's brand associations and ethnocentrism in the lion's port
Authors: O'Cass Aron , Lim Kenny
Published: August 2002

This study examines consumer brand associations, focusing on the differences in price perceptions, self‐image, and brand–image congruency held for Western and Eastern brands of fashion clothing by young Singaporeans. The study also examines consumer ethnocentric tendencies (CET), finding very low levels of ethnocentrism among respondents, and that ethnocentrism had no effect on brand preference or purchase intention for brands from different origins. © 2002 Wiley Periodicals, Inc.
One‐bond 13C–13C coupling constants in alkyl‐substituted cyclopropenes: experimental and theoretical studies
Authors: Kamieńska‐Trela Krystyna , Bernatowicz Piotr , Lüttke Wolfgang , Machinek Reinhard , Trætteberg Marit
Published: August 2002

Measurements of one‐bond carbon–carbon coupling constants, 1J(C, C), were performed for two series of compounds, alkyl‐substituted cyclopropenes and cyclopropanes. The experimental data were complemented by a set of DFT‐calculated J couplings for the parent cyclopropene (1), its methyl and silyl derivatives and, additionally, for 1‐methylcyclobutene (3), 1‐methylcyclopentene (4) and 1‐methylcyclohexene (5) and good agreement was observed between the experimental and the calculated data; all the trends are perfectly maintained, including a dramatic decrease in the couplings across endocyclic single bonds in cyclopropene and its derivatives, and a significant decrease in the corresponding couplings in cyclobutene. Using the data obtained, the s characters of the carbon hybrid orbitals involved in the formation of the cyclopropene were calculated. The results clearly show that the ring closure and the related strain exerted upon the cyclopropene molecule only slightly disturb the electron structure of the double bond. The s character of the corresponding carbon orbital is 0.314 in cyclopropene vs the theoretical value of 0.333 in ethene. This is at variance with the endo‐ and exocyclic single bonds, where the s characters of the orbitals forming the endocyclic single bonds are much smaller than those of the bonds in the open‐chain compounds, i.e. 0.229 (C‐1 and/or C‐2) and 0.166 (C‐3). The s values calculated for the exocyclic CH bonds are 0.334 for C‐3 and 0.456 for C‐1 and/or C‐2. Copyright © 2002 John Wiley & Sons, Ltd.
Phenylselenenylmenthane derivatives and their enantiomeric discrimination by 1H and 13C NMR spectroscopy in the presence of a chiral dirhodium complex
Authors: Malik Shahid , Moeller Stefan , Duddeck Helmut , Choudhary Muhammad Iqbal
Published: August 2002

The phenylselenenylmenthane and ‐menthene derivatives 1–4 were studied in terms of 1H and 13C signal assignments, conformational analysis and also complexation shifts (Δδ) and dispersion effects (Δν) observed when non‐racemic (ca 2 : 1) mixtures of the chiral selenides were exposed to an equimolar amount of the chiral dirhodium complex Rh*. The complexation site is the selenium atom exclusively. Whereas Δδ values are moderate or small, dispersed signals (split into two owing to the existence of diastereomeric adducts) can be observed, many of which are large enough for a facile determination of enantiomeric ratios of the selenides irregardless of the conformational behaviour of the selenides and the adduct composition. Thus, the ‘dirhodium method’ is simple and reliable for chiral recognition in the class of organoselenium compounds which is gaining increasing importance in developing new techniques of asymmetric synthesis. Copyright © 2002 John Wiley & Sons, Ltd.
Conformational studies on indole alkaloids from Flustra foliacea by NMR and molecular modeling
Authors: Morales‐Ríos Martha S. , Santos‐Sánchez Norma F. , Suárez‐Castillo Oscar R. , Joseph‐Nathan Pedro
Published: August 2002

1H and 13C NMR assignments for 1a–4a and 1b–4b were obtained using HSQC, HMBC and NOESY techniques. Differences and ambiguities from literature assignments are reconciled. For the pyrrolidine C‐ring, the combined use of NMR spectroscopy and molecular mechanics calculations revealed that this ring exists in a dynamic conformational equilibrium between twist (2T1) and envelope‐twist (1E–1T2) conformations. In chloroform‐d1, the 1H NMR coupling constants indicate that the pyrrolidine ring is biased in favor of the envelope‐twist conformation. Steric requirements of the N‐prenyl group enhanced the envelope‐twist (1E–1T2) conformation populations. Copyright © 2002 John Wiley & Sons, Ltd.
Semi‐analytical elastostatic analysis of unbounded two‐dimensional domains
Authors: Deeks Andrew J. , Wolf John P.
Published: August 2002

Unbounded plane stress and plane strain domains subjected to static loading undergo infinite displacements, even when the zero displacement boundary condition at infinity is enforced. However, the stress and strain fields are well behaved, and are of practical interest. This causes significant difficulty when analysis is attempted using displacement‐based numerical methods, such as the finite‐element method. To circumvent this difficulty problems of this nature are often changed subtly before analysis to limit the displacements to finite values. Such a process is unsatisfactory, as it distorts the solution in some way, and may lead to a stiffness matrix that is nearly singular. In this paper, the semi‐analytical scaled boundary finite‐element method is extended to permit the analysis of such problems without requiring any modification of the problem itself. This is possible because the governing differential equations are solved analytically in the radial direction. The displacement solutions so obtained include an infinite component, but relative motion between any two points in the unbounded domain can be computed accurately. No small arbitrary constants are introduced, no arbitrary truncation of the domain is performed, and no ill‐conditioned matrices are inverted. Copyright © 2002 John Wiley & Sons, Ltd.
Evaluation of a constitutive model for clays and sands: Part II – clay behaviour
Authors: Pestana Juan M. , Whittle Andrew J. , Gens Antonio
Published: August 2002

The undrained response of cohesive soils is of paramount importance in geomechanics and it has been modelled extensively for the last 50 years. In comparison, drained behaviour of clays has received only modest attention. Drained and undrained behaviour is significantly affected by past consolidation stress history. This paper evaluates the capabilities of the MIT‐S1 effective stress model, described in a companion paper, for predicting the anisotropic stress–strain–strength behaviour of clays. The paper illustrates the selection of model parameters for Lower Cromer Till, using data from standard types of laboratory tests. Comparison of model simulations with measured response for Lower Cromer Till and Boston Blue Clay illustrate model capabilities. The work focuses initially on comparisons of model predictions with measurements from undrained triaxial and plane strain tests on initially K0‐consolidated specimens. Comparisons with measured data from undrained shear tests performed in different modes of shearing for LCT and BBC show that the model: (a) gives excellent predictions of maximum shear stress conditions and accurately describes the non‐linear shear stress–strain behaviour; (b) accurately describes the anisotropic shear stress–strain–strength conditions for different consolidation stress histories; and (c) gives realistic description of mobilized friction angles, especially at large OCR's. The paper then focuses on the effects of consolidation stress history for isotropically consolidated specimens of resedimented Lower Cromer Till and Boston Blue Clay. Finally, the paper compares model predictions for drained shear tests on K0 and isotropically consolidated specimens with overconsolidation ratios, OCR⩽10, used to evaluate particular aspects of the critical state framework of soil behaviour. Overall, the model gives excellent predictions of the effect of initial anisotropy and overconsolidation stress history on the shear stress–strain and volumetric behaviour of clays. Copyright © 2002 John Wiley & Sons, Ltd.
High‐resolution magic angle spinning MRS of breast cancer tissue
Authors: Sitter Beathe , Sonnewald Ursula , Spraul Manfred , Fjösne Hans E. , Gribbestad Ingrid S.
Published: August 2002

High‐resolution magic angle spinning (HR MAS) may develop into a new diagnostic tool for studying intact tissue samples, and several types of cancer have been investigated with promising results. In this study HR MAS spectra of breast cancer tissue from 10 patients have been compared to conventional high‐resolution spectra of perchloric acid extracts of the same tissue type. The HR MAS spectra show resolution comparable to spectra of extracts, and two‐dimensional techniques lead to identification of a majority of the constituents. More than 30 different metabolites have been detected and assigned. To our knowledge this is the most detailed assignment of biochemical components in intact human breast tissue. The spectra of intact breast cancer tissue differ from perchloric acid extracts by the presence of lipids and fewer signals in the low field region. HR MAS analysis of intact breast tissue specimens is a rapid method, providing spectra with resolution where relative quantification of the majority of the detected metabolites is possible. Copyright © 2002 John Wiley & Sons, Ltd.
The effects of drugs modulating K+ transport on Rb+ uptake and distribution in pig hearts following regional ischemia: 87Rb MRI study
Authors: Kupriyanov Valery V. , Xiang Bo , Sun Jiankang , Jilkina Olga
Published: August 2002

The effects of drugs that can modulate passive permeability of K+ into cardiomyocytes in normal and reperfusion‐damaged cardiac muscle were assessed. Rubidium ion (Rb+) was used as a K+ tracer and 87Rb‐MRI as a detection method. The left anterior descending artery (LAD) of isolated pig hearts perfused with Krebs–Henseleit buffer (KHB) was occluded for 2 h and subsequently reperfused for 2 h with KHB containing 4.7 mM RbCl instead of KCl. The buffer contained either a blocker of ATP‐sensitive K+ channels (KATP), glibenclamide (Glib, 3 µM), a KATP opener, pinacidil (Pin, 10 µM), a K+/Na+/2Cl− co‐transporter inhibitor, bumetanide (Bum, 10 µM) or no drug (control). Upon reperfusion three‐dimensional 87Rb MR images were acquired to obtain kinetics of Rb+ uptake and its distribution. Areas at risk (AAR) and areas of necrosis were determined by Evans Blue and triphenyl tetrazolium chloride staining, respectively. Rb+ uptake kinetics in the remote posterior (Pos) wall were similar in all groups. The kinetics remained monoexponential in the affected anterior (Ant) wall and the uptake rates were 32, 36, 37 and 21% of that in the Pos wall in the control, Glib, Pin and Bum groups, respectively. Infarct sizes determined histologically as a percentage of total ventricular (left + right) mass (14–22%) corresponded to sizes of areas with 20–40% of maximal Rb image intensity [I(Rb)max, 15–22%], except for the Pin group (12.5 vs 21%). The sizes of areas with 20–50% of I(Rb)max (30–36%) closely correlated with those of AAR determined histologically (31–33%). Lactate dehydrogenase release did not differ in all groups. We conclude that: (1) reperfusion damage quickly inhibits Rb+ uptake; (2) Rb+ uptake in normal and reperfused tissue does not significantly depend on KATP or the K+/Na+/2Cl− cotransporter; (3) areas with 20–40% of maximal image intensity correspond to infarct areas. Copyright © 2002 John Wiley & Sons, Ltd.
Networking lessons in delivering ‘Software as a Service’—part I
Authors: Greschler David , Mangan Tim
Published: August 2002

This is a two‐part paper. In part I, we describe the origins of Software as a Service (SaaS) and its value proposition to Corporate IT, Service Providers, Independent Software Vendors, and End Users. In part II, we examine the networking lessons learned in researching, building, and running a SaaS service. Copyright © 2002 John Wiley & Sons, Ltd.
An efficient diagonal preconditioner for finite element solution of Biot's consolidation equations
Authors: Phoon K. K. , Toh K. C. , Chan S. H. , Lee F. H.
Published: August 2002

Finite element simulations of very large‐scale soil–structure interaction problems (e.g. excavations, tunnelling, pile‐rafts, etc.) typically involve the solution of a very large, ill‐conditioned, and indefinite Biot system of equations. The traditional preconditioned conjugate gradient solver coupled with the standard Jacobi (SJ) preconditioner can be very inefficient for this class of problems. This paper presents a robust generalized Jacobi (GJ) preconditioner that is extremely effective for solving very large‐scale Biot's finite element equations using the symmetric quasi‐minimal residual method. The GJ preconditioner can be formed, inverted, and implemented within an ‘element‐by‐element’ framework as readily as the SJ preconditioner. It was derived as a diagonal approximation to a theoretical form, which can be proven mathematically to possess an attractive eigenvalue clustering property. The effectiveness of the GJ preconditioner over a wide range of soil stiffness and permeability was demonstrated numerically using a simple three‐dimensional footing problem. This paper casts a new perspective on the potentialities of the simple diagonal preconditioner, which has been commonly perceived as being useful only in situations where it can serve as an approximate inverse to a diagonally dominant coefficient matrix. Copyright © 2002 John Wiley & Sons, Ltd.
Linear and non‐linear finite element error estimation based on assumed strain fields
Authors: Gabaldón F. , Goicolea J. M.
Published: August 2002

In this work we analyse the use of enhanced strain fields for the purpose of error estimation in finite element solid mechanics applications. The proposed approach evaluates the quality of the solution for standard Galerkin displacement elements, taking into account the enrichment of the solution with enhanced assumed strain mixed elements. The contribution of the enhanced strain modes is measured with an energy norm.

The method proposed has two interesting advantages. Firstly, it results in a local formulation which is evaluated element by element. Secondly, it is easily extended to non‐linear problems. In this work, the formulation is developed for linear elasticity, for finite strain elasticity, and von Mises small strain plasticity.

Finally, some representative numerical simulations are presented which show in practice the performance of the method. Copyright © 2002 John Wiley & Sons, Ltd.
Flow‐induced vibrations of non‐linear cables. Part 2: Simulations
Authors: Lucor D. , Evangelinos C. , Imas L. , Karniadakis G. E.
Published: August 2002

In this paper, we present simulations of flow interacting with non‐linear cables. We first consider the case of a pre‐stretched straight cable subject to uniform inflow, which eventually assumes a catenary‐like equilibrium position. We then simulate the flow induced by a riser of an S shape at equilibrium, subject to time‐periodic forcing at one of its ends. We demonstrate that the models and algorithms developed in Part 1 of this work can be used effectively in simulating flow‐structure interactions in non‐linear systems of industrial complexity. Copyright © 2002 John Wiley & Sons, Ltd.
A new finite‐element formulation for electromechanical boundary value problems
Authors: Landis Chad M.
Published: August 2002

In this paper, a new finite‐element formulation for the solution of electromechanical boundary value problems is presented. As opposed to the standard formulation that uses scalar electric potential as nodal variables, this new formulation implements a vector potential from which components of electric displacement are derived. For linear piezoelectric materials with positive definite material moduli, the resulting finite‐element stiffness matrix from the vector potential formulation is also positive definite. If the material is non‐linear in a fashion characteristic of ferroelectric materials, it is demonstrated that a straightforward iterative solution procedure is unstable for the standard scalar potential formulation, but stable for the new vector potential formulation. Finally, the method is used to compute fields around a crack tip in an idealized non‐linear ferroelectric material, and results are compared to an analytical solution. Copyright © 2002 John Wiley & Sons, Ltd.
New smoothing techniques for solving bang–bang optimal control problems—numerical results and statistical interpretation
Authors: Bertrand R. , Epenoy R.
Published: August 2002

In this paper, we investigate the solution of bang‐bang optimal control problems by shooting methods. We will show how modifying the performance index by a term depending on a small parameter ε yields more regular controls and shooting functions. A continuation procedure on ε will lead us to a good approximation of the initial solution. Then, a statistical interpretation of the method is given, providing us with a general framework for building new regular controls. Finally, two numerical examples are solved illustrating the interest of our method. Copyright © 2002 John Wiley & Sons, Ltd.
Toxicological and mechanistic studies on neonicotinoid cross resistance in Q‐type Bemisia tabaci (Hemiptera: Aleyrodidae)
Authors: Nauen Ralf , Stumpf Natascha , Elbert Alfred
Published: August 2002

The tobacco whitefly, Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) is a serious pest in numerous cropping systems and has developed a high degree of resistance against several chemical classes of insecticides. One of the latest group of insecticides introduced to the market were the neonicotinoids (chloronicotinyls), acting agonistically on insect nicotinic acetylcholine receptors. Resistance to neonicotinoid insecticides has recently been shown to occur, especially in Q‐type B tabaci in some places in Almeria, Spain, whereas control of B‐type B tabaci in many other intense cropping systems worldwide has remained on high levels. Our study revealed that neonicotinoid‐resistant Q‐type strains from Almeria were often more than 100‐fold less susceptible to thiamethoxam, acetamiprid and imidacloprid when tested in discontinuous systemic laboratory bioassays. The resistance factors were generally 2‐ to 3‐fold lower in leaf‐dip bioassays. In addition to the Spanish strains, we obtained two other highly neonicotinoid‐cross‐resistant B tabaci greenhouse populations, one from Italy (December 1999) and one from Germany (June 2001). A molecular diagnostic analysis revealed that both strains also belong to the (Spanish) subtype Q of the B tabaci species complex. The resistance levels of Q‐type whitefly strains derived from Almeria greenhouses in 1999 remained stable for at least two years, even when maintained in the laboratory without any selection pressure. The biochemical mechanisms conferring resistance to neonicotinoids have not yet been elucidated in detail, but synergist studies suggested a possible involvement of microsomal monooxygenases. Furthermore, we checked two Almerian strains of B tabaci isolated in 1998 and 1999 and demonstrated that neonicotinoid resistance is not due to an altered [3H]imidacloprid binding site of nicotinic acetylcholine receptors.

© 2002 Society of Chemical Industry
Evaluation of metabolic detoxifying enzyme activities and insecticide resistance in Frankliniella occidentalis
Authors: Maymó Ana C , Cervera Amelia , Sarabia Raquel , Martínez‐Pardo Rafael , Garcerá M Dolores
Published: August 2002

The western flower thrips Frankliniella occidentalis (Pergande) is a very significant pest of a number of different agricultural crops in the south‐east of Spain. The importance of thrips as a pest is not due mainly to the direct damage inflicted on the plant, but to the loss in commercial value which occurs as a consequence of the development of dark spots caused by the tomato spotted wilt virus (TSWV) which they transmit. The economic threshold is therefore almost zero, which enhances the problems of resistance management. The present work is part of a global project that attempts to evaluate the status of insecticide resistance in field populations of thrips obtained from several agricultural crops. We have studied, in either individual or pooled insects, some enzyme systems classically related to detoxification of insecticides: esterases and glutathione‐S‐transferase (GST). The activity of these enzymes from laboratory populations selected with various classes of insecticides has also been measured using several appropriate substrates. An increase in GST mean activity was found in two field‐collected strains. Differences in frequency distributions of esterase and GST activities were found for both field‐collected strains and for a laboratory strain selected with acrinathrin. These activities were compared with those of a wild‐type reference strain.

© 2002 Society of Chemical Industry
Natural variation in baseline data: when do we call a new sample ‘resistant’?
Authors: Schaub Lukas , Sardy Sylvain , Capkun Gorana
Published: August 2002

Mortality of pear psylla to amitraz was studied by means of bioassays. Variation between samples, temporal variation within the season in one orchard and spatial variation between Swiss regions were considered. Variation between samples was large enough to produce different Probit functions and LC50 values. Temporal and spatial variations were too small to indicate resistance. Prediction intervals of the pooled functions using bootstrapping were calculated to determine if future samples come from a population with decreased sensitivity. Probabilistic criteria on the population level were proposed for resistance.

© 2002 Society of Chemical Industry
Studies on the synthesis of cyclic pentapeptides as LHRH antagonists and the factors that influence cyclization yield
Authors: Gao Xing‐Ming , Ye Yun‐Hua , Bernd Michael , Kutscher Bernhard
Published: August 2002

Six cyclic pentapeptides containing two or three non‐protein amino acids have been synthesized by cyclization of linear precursors in dilute solution and characterized by TLC, HPLC, NMR, melting point, specific rotation etc. A total of 72 cyclization reactions were carried out to study the factors that influence head‐to‐tail cyclization: linear precursor sequence, coupling reagent, residue configuration, the proportion of DMAP additive, concentration, reaction temperature and reaction time. The cyclic pentapeptides will be modified by active moieties and evaluated as LHRH antagonists. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Khat: pharmacological and medical aspects and its social use in Yemen
Authors: Al‐Motarreb Ahmed , Baker Kathryn , Broadley Kenneth J
Published: August 2002

Fresh leaves of the khat tree (Catha edulis Forsk.) are chewed for their euphoric properties in East Africa and parts of the Middle East, such as The Yemen. This review describes the history, cultivation and constituents of khat, and the social aspects of khat chewing in Yemen. The major pharmacologically active constituent of the fresh leaves is (−)‐S‐cathinone. The pharmacology of (−)‐S‐cathinone in the central nervous system and the peripheral effects are described. (−)‐S‐Cathinone is regarded as an amphetamine‐like sympathomimetic amine and this mechanism of action is discussed in relation to the central stimulant actions and the cardiovascular effects of increasing blood pressure and heart rate. The risk factors associated with khat chewing are described, with emphasis on the reported increased incidence of acute myocardial infarction. Copyright © 2002 John Wiley & Sons, Ltd.
Hypolipidaemic activity of seaweed from Karachi coast
Authors: Ara Jehan , Sultana Viqar , Qasim Rashida , Ahmad Viqar Uddin
Published: August 2002

During the present study, ethanol extracts of five seaweed species Solieria robusta, Iyengaria stellata, Colpomenia sinuosa, Spatoglossum asperum and Caulerpa racemosa at 10 mg/ 200 g body weight were tested for their hypolipidaemic activity. All the species significantly decreased the serum total cholesterol, triglyceride and low density lipoprotein cholesterol levels in normal, triton‐induced and diet‐induced hyperlipidaemic rats. Solieria robusta was found to be the most effective in reducing the lipid profile, particularly in diet‐induced hyperlipidaemic rats. A beneficial effect of the ethanol extract of S. asperum was also found on cardiac and liver enzymes in diet‐induced hyperlipidaemic rats. Copyright © 2002 John Wiley & Sons, Ltd.
The acetone soluble fraction from bark extract of Stryphnodendron adstringens (Mart.) Coville inhibits gastric acid secretion and experimental gastric ulceration in rats
Authors: Martins D. T. O. , Lima J. C. S. , Rao V. S. N.
Published: August 2002

The acetone soluble fraction from a crude methanol extract of Stryphnodendron adstringens stem bark (AFSAB) was evaluated in acute (ethanol, indomethacin and hypothermic restraint‐stress) and chronic (acetic acid) models of gastric ulceration and on basal and bethanechol‐stimulated gastric acid secretion in rats. Rats pretreated orally with AFSAB at doses of 400 and 800 mg/kg showed significant decreases of gastric lesion scores in ethanol (62% and 98%) and hypothermic restraint‐stress (89% and 88%) models but exerted no significant influence on indomethacin‐induced acute or acetic acid‐induced chronic ulceration. In pylorus‐ligated rats, AFSAB significantly decreased the basal as well as bethanechol‐stimulated gastric secretory volume and the total acidity with an elevated pH value. AFSAB failed to modify the gastric mucus and the gastric wall nonprotein‐sulphydryl content. These results point to a possible antisecretory effect of AFSAB which account for the observed antiulcer activity in ethanol and hypothermic restraint‐stress induced models of acute gastric ulceration. Copyright © 2002 John Wiley & Sons, Ltd.
Susceptibility of some clinical isolates of Staphylococcus aureus to bioactive column fractions from the lichen Ramalina farinacea (L.) Ach.
Authors: Esimone C. O. , Adikwu M. U.
Published: August 2002

The antimicrobial activities of two bioactive column chromatographic fractions (RF1 and RF2) from the lichen Ramalina farinacea (L.) were evaluated against 15 clinical isolates of Staphylococcus aureus. The susceptibility pattern of the isolates towards tetracycline (TCN) and ampicillin (AMP) was similarly ­evaluated for comparison purposes. The results show that RF1 and RF2 with an MIC90 ( minimum ­inhibitory concentration against 90% of the isolates) of 535.5 and 317 μg/mL respectively, performed generally better than TCN and AMP with an MIC90 of 976.5 and 357 μg/mL respectively. Copyright © 2002 John Wiley & Sons, Ltd.
Ab initio study of the CuPt3 cluster with H2 interaction
Authors: Anguiano A. , Cruz A. , Bertin V. , Poulain E. , Castillo S.
Published: August 2002

The CuPt3 cluster with H2 interaction was studied by means of Hartree–Fock self‐consistent field (HF‐SCF) and multiconfigurational SCF plus variational and multireference second‐order Möller–Plesset perturbational configuration interaction (CIPSI) calculations, using relativistic core potentials. The CuPt3‐H2 interaction was carried out in Cs symmetry for both: the H2 in the Cs reflecting plane and bisected by the Cs reflecting plane. The valence electronic configuration and energy separation of the three low‐lying states of CuPt3 tetrahedral pyramid cluster was determined: 2A″, 2A′, and 4A′ electronic states. We found that the (2A″) ground state captures and dissociates H2 without energy barriers only by a Pt vertex of the CuPt3 cluster. Also, the CuPt3 cluster, in its (2A′) first excited state, by the Cu or Pt center can capture and dissociate the H2 molecule. Meanwhile, the same state for the CuPt2 and Pt3 face can capture and break H2. We have found that CuPt3 cluster in its (4A′) second excited state spontaneously activates and breaks the hydrogen molecule, with some exception, when H2 is approaching to a copper vertex. In this work we found that the CuPt3‐H2 and Pt4‐H2 interactions show similar capture and activation of H2 behaviors such as depth of wells, barriers, adsorption distances, and HH bond relaxation. Even in the case of a single Pt atom substitution by a Cu in a Pt4 cluster, there is no loss of the H2 activity compared with pure metal cluster. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Coherent states for anharmonic diatomic molecules
Authors: Récamier J. , García de León P. , Jáuregui R. , Frank A. , Castaños O.
Published: August 2002

In this work, we construct approximate coherent states for a Morse‐like potential using the displacement operator method and a method recently proposed by Gazeau and Klauder. To test if these states are minimum uncertainty states, we evaluate the temporal evolution of the dispersions in position and momentum. We also construct the trajectories in the phase space and compare with the classic solution. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Improvement of the depth resolution in sputter depth profiling by elastic peak electron spectroscopy
Authors: Kesler V. , Hofmann S.
Published: August 2002

Sputter depth profiling using elastic peak electron spectroscopy (EPES) is applied to a Ge/Si multilayer structure. The results are evaluated quantitatively using the mixing–roughness–information depth (MRI) model. It is shown that for an elastic peak energy of 1.0 keV the information depth is considerably lower (0.8 nm) compared with that of the Ge LMM (1147 eV) peak (1.6 nm) used in AES depth profiling, resulting in a respectively improved depth resolution for EPES profiling under otherwise similar conditions. Because of the high signal‐to‐noise ratio, EPES depth profiling is successfully applied to measure small diffusion lengths of the order of 1 nm at Ge/Si interfaces. Copyright © 2002 John Wiley & Sons, Ltd.
Imaging XPS investigation of the lateral distribution of copper inclusions at the abraded surface of 2024T3 aluminium alloy and adsorption of decyl phosphonic acid
Authors: Roberts Adam , Engelberg Dirk , Liu Yanwen , Thompson George E. , Alexander Morgan R.
Published: August 2002

The XPS images of copper‐rich intermetallic particles in an aluminium alloy have been obtained after argon ion removal of the oxide at the surface of mechanically polished 2024T3 alloy. Comparison of the XPS analysis before and after etching indicates that the oxide does not include significant concentrations of copper. Through analogy with copper incorporation into anodic films, it is proposed that incorporation into the oxide would only occur after preferential oxidation of aluminium and enrichment of copper immediately below the oxide film.

Self‐assembling monolayers of decyl phosphonic acid (DPA) have been adsorbed to the surface of 2024T3 alloy and superpure Al. The lateral distribution was mapped with XPS using the characteristic P 2s signal. The distribution of DPA was relatively uniform on both MS‐Al and 2024T3. This is consistent with the model of the alloy surface constructed from the imaging XPS analysis, which suggests that the oxide on the large particles is close in composition to that on to the surrounding matrix. Copyright © 2002 John Wiley & Sons, Ltd.
Oxygen beam SIMS depth profiling of Si1−xGex layers: transient processes
Authors: Krüger D. , Efremov A. A. , Murota J. , Kurps R. , Bugiel E. , Tillack B. , Romanova G. Ph.
Published: August 2002

Characterization of shallow dopant profiles near surfaces and interfaces in Si1−xGex layers by secondary ion mass spectroscopy (SIMS) is a challenge in advanced Si‐based technologies. In standard SIMS, quantification with confidence is possible only in the dynamic steady state of the measurement after completing a transient period. Therefore, we analyse the transient processes during oxygen bombardment and sputtering of epitaxial Si1−xGex layers, which were grown by low‐pressure chemical vapour deposition (LPCVD) with different compositions (0 < x < 0.75). We show that a drop of the Ge+ secondary ion yield near the end of the transient period in epitaxial Si1−xGex layers extends this period in comparison with pure Si. We demonstrate that the drop is a function of layer composition and bombardment parameters, such as primary ion beam energy and erosion rate. We show that an interfacial transient period after crossing a Si/Si1−xGex interface can be neglected if the formation of the oxygen‐beam‐induced altered layer is completed within the Si cap layer before reaching the interface between the cap and the Si1−xGex layer. This allows reliable quantification of dopant spikes within a few nanometers near to interfaces. By means of computer modelling we describe secondary ion emission kinetics and simulate the dynamics of structural and compositional changes in the subsurface region of Si1−xGex alloys caused by interaction with oxygen beams. Experimental and theoretical time dependencies for secondary ion yields are in good accordance; the dependence of the Ge+ intensity drop on the Ge concentration is simulated and experimentally proved. Copyright © 2002 John Wiley & Sons, Ltd.
A multistate model for the genetic analysis of the ageing process
Authors: Giard Nicole , Lichtenstein Paul , Yashin Anatoli I.
Published: August 2002

In this paper a multivariate frailty model is suggested that can be used in the genetic analysis of the ageing process as a whole, simplified to consisting of the states ‘healthy’, ‘disabled’ and ‘deceased’. The model allows us to evaluate simultaneously the relative magnitude of genetic and environmental influences on frailty variables corresponding to the period of good health and to the life span. The frailty variables can be interpreted as susceptibility to illness or death. The model can be applied to data on groups of related individuals (twins, siblings, a litter). One of the major advantages of this model is that it allows one to include groups of individuals where some or all members of the group are already deceased at the time of observation. The current health status of the living individuals and the exact life span of individuals who are already deceased is the only information necessary for the application of the model. Questions concerning the identifiability of the model based on current health status data and estimation strategies are discussed in the context of specifying the model for twins. Finally, the results of a sample analysis of twin data on prostate cancer are presented. Copyright 2002 John Wiley & Sons, Ltd.
Estimating a treatment effect in survival studies in which patients switch treatment
Authors: Branson Michael , Whitehead John
Published: August 2002

For disease indications such as Acquired Immune Deficiency Syndrome (AIDS) and various cancers, randomization to a pure control treatment may be scientifically desirable but not ethically acceptable. Clinicians may insist that the experimental treatment be made available, at least as a rescue medication, for all patients in the control arm. A method for estimating a treatment effect in survival data from randomized clinical trials of this type is developed under an accelerated failure time model. This approach retains all patients in the groups to which they were randomized and is not based on an ad hoc subgroup analysis. By conditioning on having observed patient switch times, this method avoids the need to model patient switching patterns in the analysis. This new approach is evaluated using simulation studies, and is illustrated through analysing data from a Medical Research Council lung cancer trial. Copyright © 2002 John Wiley & Sons, Ltd.
Assessing the gain in diagnostic performance when combining two diagnostic tests
Authors: Macaskill Petra , Walter Stephen D. , Irwig Les , Franco Eduardo L.
Published: August 2002

Combining dichotomous (or dichotomized) results of two diagnostic tests will result in a trade‐off in sensitivity and specificity of the combined test relative to the component tests. Because of this inherent trade‐off, likelihood ratios provide a clinically relevant means of comparing the combined test with one of its components. The likelihood ratios depend on both sensitivity and specificity and hence take into account the trade‐off between them. A graphical approach is used to assess whether the combined test is superior to a component test, or vice versa. Asymptotic standard errors are derived for comparing likelihood ratios when a paired study design is used. The trade‐off in the expected number of additional true positive and false positive results (or true negative and false negative results) is used as the basis for deciding whether to use tests in combination when neither the combined nor a component test shows superior test performance based on their likelihood ratios. These methods are illustrated with an example that considers the combined use of Pap and HPV testing. Copyright © 2002 John Wiley & Sons, Ltd.
Board composition, share ownership, and ‘underpricing’ of U.K. IPO firms
Authors: Filatotchev Igor , Bishop Kate
Published: August 2002

Using a sample of 251 IPOs in the United Kingdom, this paper examines interlinks between executive and nonexecutive characteristics, share ownership, and short‐term performance measured in terms of share offer ‘underpricing.’ It argues that executives' power and previous experience directly affect ex ante choice of nonexecutive directors and their ownership interests in the firm. These endogenously developed governance factors may be used by IPO teams strategically to reduce the extent of underpricing. However, there is a selective response of investors to different board characteristics and share ownership structure. Copyright © 2002 John Wiley & Sons, Ltd.
Effects of hysteretic model on seismic demands: consideration of near‐fault ground motions
Authors: Loh Chin‐Hsiung , Wan Shiuan , Liao Wen‐I
Published: August 2002

This paper summarizes the results of a study that is to evaluate the structural response attributes of near‐fault ground motion. Ground motion recordings from the Chi‐Chi earthquake are used as inputs to the structural system. An improved nonlinear hysteretic model, based on the experimental study, was used to calculate the response of the single degree‐of‐freedom inelastic system. Comparison of the results of analysis with traditional elastic–perfect plastic mode calculations was made. Discussions on the inelastic design spectrum, particularly the code‐specified base shear coefficients, using the improved nonlinear hysteretic model incorporated with the near‐fault input ground motion are made. Copyright © 2002 John Wiley & Sons, Ltd.
Selective combined control stiffness and magnetorheological damping system in nonlinear multistorey structures
Authors: Ribakov Y. , Gluck J.
Published: August 2002

The application of a combined controlled stiffness and magnetorheological (MR) damping system in a base‐isolated nonlinear multistorey structure with amplifying braces is described. Passive control theory is used to obtain the viscous characteristics of the MR damper fluid. Selective control of the proposed system is used to enhance the behaviour of a structure during earthquakes. The nonlinear equations of motion are solved using the Wilson θ method. The control forces are obtained using instantaneous control theory with the predictive control approach. The efficiency of the proposed system is demonstrated by a numerical simulation of a seven‐storey building subjected to four different earthquakes. The stimulation shows that the behaviour of the selective controlled structure with the proposed damping system is significantly improved compared to that of an uncontrolled structure. The energy required for the adjustment of the proposed system with amplifying braces is much lower compared to that of the case of MR dampers connected directly to chevron braces. The response of the predictive controlled structure is close to that of an instantaneous controlled structure. Copyright © 2002 John Wiley & Sons, Ltd.
Critical loads of lateral load resisting structures for tall buildings
Authors: Hoenderkamp J. C. D.
Published: August 2002

A simplified hand method of analysis is presented for the calculation of the overall critical load of planar lateral load resisting structures commonly used to provide stability in tall buildings. They may comprise three stiffness components: bending and shear stiffness in addition to a rotational spring stiffness at the base of the structure. The method requires the calculation of three individual critical loads which are then combined to yield the structural critical load. This allows a rapid assessment of second‐order effects on the horizontal displacements and bending moments. The method is most accurate for structures with uniform geometry up the height and is therefore best suited for preliminary stages of design and checking the reasonableness of the results from computer analyses. Copyright © 2002 John Wiley & Sons, Ltd.
SINGLE TREATMENT (HORMONAL IMPRINTING) OF NEWBORN RATS WITH SEROTONIN INCREASES THE SEROTONIN CONTENT OF CELLS IN ADULTS
Authors: Csaba György , Kovács Péter , Pállinger Éva
Published: August 2002

Hormonal imprinting takes place perinatally at the first encounter between the hormone and its target receptor, causing the finishment of the maturation of receptor—signal transduction system. In the presence of an excess of the target hormone or related molecules faulty imprinting develops with life‐long consequences. In earlier experiments single neonatal treatment with minute dose of IL‐6 caused also prolonged stimulation of IL‐6 production. In the present experiment newborn female and male rats were treated with 20μg serotonin (hormonal imprinting) and were studied for serotonin content of different cell types in adult age. Serotonin content was measured by flow cytometry and its localization was determined by confocal microscopy. Serotonin content was detected in white blood cells (lymphocytes, monocytes and granulocytes); in lymphocytes, monocytes (macrophages), granulocytes and mast cells of peritoneal fluid and thymic lymphocytes. Serotonin was present in all cell types of control animals studied. Serotonin content extremely elevated in the white blood cells and also increased in the peritoneal cells of neonatally treated female animals. There was no elevation in thymic lymphocytes. The mean values of male animals remained at the control level. The experiments call attention to the life‐long effect of the perinatal hormonal imprinting manifested presently in the elevation of serotonin content and point to the gender differences of serotonin imprinting. Considering the role of serotonin in mood and psychiatric diseases, the observations could have some clinical importance.
FRACTIONATION ANALYSIS OF THE ENDOSOMAL COMPARTMENT DURING RAT RETICULOCYTE MATURATION
Authors: Dardalhon Valérie , Géminard Charles , Reggio Hubert , Vidal Michel , Sainte‐Marie Josette
Published: August 2002

A subcellular fractionation procedure was developed to isolate the different endosomal compartments present during reticulocyte maturation. After reticulocyte lysis and removal of excess haemoglobin by gel chromatography, membrane vesicles were separated over a discontinuous sucrose gradient (10–40%). Two fractions were isolated: P1 at the 25–35% sucrose interface and P2 at the 17–25% sucrose interface. These fractions were morphologically characterized by electron microscopy and the distribution of endocytic markers in the fractions was detected by Western blot. Moreover, this fractionation technique was used to study the effect of 3‐methyladenine (3‐MA), an autophagy inhibitor, on reticulocyte maturation. The presence of 3‐MA during in vitro maturation of reticulocytes induced a decrease in exosome secretion, as measured by the amount of transferrin receptor (TfR) released in the extracellular medium. The subcellular fractionation results suggested that multivesicular endosome formation from early endosomes is the step affected by 3‐MA.
DIVISION AND DEATH OF CELLS IN DEVELOPING SYNOVIAL JOINTS AND LONG BONES
Authors: Kavanagh Emma , Abiri Mersedeh , Bland Yvette S. , Ashhurst Doreen E.
Published: August 2002

Articular chondrocytes are a unique set of cells from the time the cellular condensations that become the anlagen of the long bones develop in the embryo. In the presumptive joint the cells of the opposing bones are packed very closely together, but at cavitation, the central, flattened cells move apart to form the articular surfaces. As the articular cartilage develops the cells are pushed further apart by the cartilaginous matrix. To determine the contributions of cell proliferation and death to cavitation and the subsequent development and growth of articular cartilage, direct observations were made to identify mitotic cells and those with apoptotic bodies in haematoxylin‐stained sections of developing joints, and growing and ageing articular cartilage of the rabbit knee. These observations were extended using antibodies to the proliferating cell nuclear antigen (PCNA) and TdT‐mediated dUTP nick end labelling (TUNEL) on corresponding sections. Low levels of cell division do occur in the articular cartilage up to 6 weeks postnatally, but matrix formation makes the major contribution to the increase in size of the cartilage. Cell death is not observed during cavitation, nor during the development of the articular cartilage proper. Apoptosis is essential, however, for the removal of the epiphyseal cartilage during ossification of the epiphyses and in the growth plate.
INSULIN‐LIKE GROWTH FACTOR‐II INDUCES HYPERTROPHY OF ADULT CARDIOMYOCYTES VIA TWO ALTERNATIVE PATHWAYS
Authors: Huang Chih‐Yang , Hao Ling‐Yang , Buetow Dennis E.
Published: August 2002

Insulin‐like growth factor (IGF)‐II is known to induce hypertrophy of isolated adult rat ventricular cardiomyocytes cultured in the absence of serum. However, it is not known how the growth factor exerts this hypertrophic effect. We show here that IGF‐II induces hypertrophy of the cultured cardiomyocytes via two alternative pathways: (1) an IGF‐I receptor‐dependent pathway, or (2) a lysosome‐dependent pathway when the IGF‐I receptor‐dependent pathway is blocked.