bluuebunny/crossref_metadata_2025_split huggingface dataset:
The group B coxsackieviruses and myocarditis
Authors: Kim Kyung‐Soo , Hufnagel Günter , Chapman Nora M. , Tracy Steven 
Published: August 2002

AbstractThe six serotypes of the group B coxsackieviruses (CVB) are common human enteroviruses linked etiologically to inflammatory cardiomyopathies. This has been demonstrated by molecular detection of enteroviral RNA in human heart tissue, serologic associations with disease, and virus isolation from cases of fulminant myocarditis. The murine model of CVB‒associated myocarditis has demonstrated that CVB can be attenuated through mutations at different genomic sites. Human CVB3 isolates demonstrate varying degrees of cardiovirulence in the murine model; one site of virulence determination has been mapped to domain II of the 5′ non‒translated region. The interplay of CVB replication and the immune response to that replication in the heart is a complex interaction determining the extent to which the virus replication is limited and the degree to which a pathogenic inflammation of cardiac muscle occurs. Studies of CVB3‒induced myocarditis in murine strains lacking subsets of the immune system or genes regulating the immune response have demonstrated a pivotal role of the T cell response to the generation of myocarditis. While CVB are associated with 20–25% of cases of myocarditis or cardiomyopathy, the severity of the disease and the existence of attenuated strains shown to generate protective immunity in animal models indicates that vaccination against the CVBs would be valuable. Copyright © 2001 John Wiley & Sons, Ltd.
Interactions of SV40 large T antigen and other viral proteins with retinoblastoma tumour suppressor
Authors: Lee Changwook , Cho Yunje 
Published: August 2002

AbstractSimian virus 40 large T antigen, human papilloma virus E7 and adenovirus E1A are all potent oncoproteins that can induce several types of tumours. One of the major functions of these oncoproteins is to interact with the retinoblastoma tumour suppressor protein, Rb, a master switch of the mammalian cell cycle, and to inactivate its function. Rb promotes cell‐cycle arrest by recruiting and regulating proteins involved in the transcription of cell proliferation genes. The binding of viral oncoproteins to Rb disrupts the Rb–E2F complex, a central component in the Rb‐mediated cell‐cycle network. The crystal structures of Rb pocket–viral oncoprotein complexes indicate that the viral proteins recognise a highly conserved region in the Rb pocket through a common motif, LxCxE, and through other unique regions within each viral protein. Although the mechanism of Rb inactivation by viral proteins is not fully understood, information at the atomic level about the interactions between the Rb pocket and viral proteins is providing some insights into how viral proteins dissociate E2F from Rb and thus how they deregulate the cell cycle. Copyright © 2002 John Wiley & Sons, Ltd.
The constant‐Jacobian method for kinematics of a three‐DOF planar micro‐motion stage
Authors: Zhang W. J. , Zou J. , Watson L. G. , Zhao W. , Zong G. H. , Bi S. S. 
Published: August 2002

AbstractThis paper concerns the development of a class of devices that generate end‐effector motion in the
range of less than 100 μm and with sub‐nanometer resolution; in particular, a parallel manipulator
configuration that generates a planar x‐y‐γ motion is considered. The parallel
manipulator is implemented as a compliant mechanism. A problem with parallel manipulators is that the forward
kinematics is usually too complex, which can hinder the implementation of advanced control algorithms. The
contribution of this paper is that a simple method, called the constant‐Jacobian (CJ) method, is
developed based on the pseudo‐rigid body (PRB) approach to compliant mechanisms. The experiment
validates the CJ method. © 2002 John Wiley & Sons, Inc.
The synthesis of planar parallel manipulators with prismatic joints for an optimal, singularity‐free workspace
Authors: Gallant Marise , Boudreau Roger 
Published: August 2002

AbstractThe synthesis of three‐degree‐of‐freedom planar parallel manipulators is performed using
a genetic algorithm. The architecture of a manipulator and its position and orientation with respect to a
prescribed workspace are determined.The architectural parameters are optimized so that the manipulator's constant‐orientation
workspace is as close as possible to a prescribed workspace. The manipulator's workspace is discretized and
its dexterity is computed as a global property of the manipulator. An analytical expression of the singularity
loci (local null dexterity) can be obtained from the Jacobian matrix determinant, and its intersection
with the manipulator's workspace may be verified and avoided.Results are shown for different conditions. First, the manipulators' workspaces are optimized for a
prescribed workspace, without considering whether the singularity loci intersect it or not. Then the same type of
optimization is performed, taking intersections with the singularity loci into account. In the following results,
the optimization of the manipulator's dexterity is also included in an objective function, along with the
workspace optimization and the avoidance of singularity loci. Results show that the end‐effector's
location has a significant effect on the manipulator's dexterity. © 2002 John Wiley & Sons,
Inc.
Addendum to ‘avoiding a giant component’
Authors: Bohman Tom , Frieze Alan 
Published: August 2002

AbstractWe take this opportunity, which is kindly provided by the editors, to add a theorem and to correct the proof of one of the lemmas in the article ‘Avoiding a Giant Component’ [Bohman and Frieze, Avoiding a giant component, Random Struct Alg 19 (2001), 75–85]. The subject of the said article is the following guided random process. Let e1, \documentclass{article}\pagestyle{empty}\begin{document}$e^{\prime}_{1}$\end{document}; e2, \documentclass{article}\pagestyle{empty}\begin{document}$e^{\prime}_{2}$\end{document};…;ei, \documentclass{article}\pagestyle{empty}\begin{document}$e^{\prime}_{i}$\end{document};… be a sequence of ordered pairs of edges chosen uniformly at random from the edge set of the complete graph Kn. This sequence is used to form a graph by choosing at stage i, i=1,…, one edge from ei, \documentclass{article}\pagestyle{empty}\begin{document}$e_{i}^{\prime}$\end{document} to be an edge in the graph, where the choice at stage i is based only on the observation of the edges that have appeared by stage i. In Bohman and Frieze [Avoiding a giant component, Random Struct Alg 19 (2001), 75–85], we proved that these choices can be made so that whp (A sequence of events ℰn is said to occur with high probability (whp) if limn→∞Pr(ℰn)=1.), the size of the largest component of the graph formed at stage. 535n, is polylogarithmic in n. Here, we make a correction to that proof and prove that the graph formed at stage cn for any constant c>1 will contain a component of size Ω(n) (regardless of how the edges are chosen at each stage). © 2002 John Wiley & Sons, Inc. Random Struct. Alg., 20, 126–130, 2002
What makes an inquiry‐oriented science teacher? The influence of learning histories on student teacher role identity and practice
Authors: Eick Charles J. , Reed Cynthia J. 
Published: August 2002

AbstractThis paper examines the influence of personal histories on the formation of early role identity as inquiry‐oriented science teachers. Two cases selected from a multicase study of 12 secondary science student teachers are used to illustrate the development of inquiry orientation. These cases represent two extremes in a continuum ranging from didactic practice to successful use of structured inquiry. The role of learners' personal histories on their teaching identity development and implications for preparing inquiry‐based science teachers are discussed. © 2002 Wiley Periodicals, Inc. Sci Ed 86:401–416, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/sce.10020
An analysis of elementary teachers' beliefs regarding the teaching and learning of science
Authors: Levitt Karen E. 
Published: August 2002

AbstractThe purpose of this study was to ascertain the beliefs of elementary teachers regarding the teaching and learning of science and the extent to which the teachers' beliefs were consistent with the philosophy underlying science education reform. Sixteen teachers from two school districts involved in a local systemic initiative for science education reform participated in the study. Each teacher was observed teaching a lesson from the program. The observation served as the context for an interview with the teacher regarding his or her beliefs about the teaching and learning of science. One overarching belief emerged: Teachers believe that the teaching and learning of science should be student centered. Five patterns of teachers' responses support this characterization of the teachers' belief. Although varying gaps exist between the teachers' beliefs and the principles of reform, the teachers' beliefs suggest that the teachers are moving in a direction consistent with science education reform. A modified case study of three teachers represents the patterns of beliefs expressed by teachers. © 2001 John Wiley & Sons, Inc. Sci Ed 86:1–22, 2001.
Interface analysis with the three‐dimensional atom probe
Authors: Miller M. K. 
Published: August 2002

AbstractThe application of the technique of atom probe tomography to the atomic scale characterization of interfaces and surface films is described. The three‐dimensional atom probe determines the coordinates and elemental identities of the atoms in a small volume of a sample with near‐atomic precision. The types of analyses that may be performed on interfaces are demonstrated by examples taken from a variety of materials, including neutron‐irradiated pressure‐vessel steel welds, superalloys, surface films and model alloys. Published in 2001 by John Wiley & Sons, Ltd.
Peak or centroid — which parameter is better suited for quantifying apparent marker locations in low‐energy sputter depth profiling with reactive primary ion beams?
Authors: Wittmaack K. , Hammerl E. , Eisele I. , Patel S. B. 
Published: August 2002

AbstractSilicon samples containing narrow boron markers were depth profiled using normally incident 0.25–1 keV O2+ ion beams in combination with secondary ion mass spectrometry (SIMS). The profiles revealed significant deviations from ideal delta distributions, either as tails or shoulders. All tracer profiles exhibited the well‐known apparent shift towards the surface, which is due to the initial decrease in erosion rate. The peak positions, $\catcode`@=11\def\curvedhat#1{\vbox{\offinterlineskip\ialign{##\crcr\hfil$\scriptscriptstyle\frown$\hfil\crcr\hfil{#1}\hfil\crcr}}}\curvedhat{z}$, showed a much more pronounced non‐linear energy‐dependent shift than the centroids, 〈z〉, up to a factor of 2 stronger. To evaluate the form of measured profiles, a reduced shape parameter is defined as Δ = 〈z〉 − $\catcode`@=11\def\curvedhat#1{\vbox{\offinterlineskip\ialign{##\crcr\hfil$\scriptscriptstyle\frown$\hfil\crcr\hfil{#1}\hfil\crcr}}}\curvedhat{z}$. For ideal deltas, this parameter can be calculated using the analytical resolution function (rf) after Dowsett et al. Depending on the orientation and magnitude of the tracer distortions, the measured values of Δ differed from Δrf by up to 0.8 nm. This difference is attributed to the fact that the ‘weight’ of the distortions gives rise to a corresponding change of 〈z〉. The results imply that (relative) marker locations are determined more safely from $\catcode`@=11\def\curvedhat#1{\vbox{\offinterlineskip\ialign{##\crcr\hfil$\scriptscriptstyle\frown$\hfil\crcr\hfil{#1}\hfil\crcr}}}\curvedhat{z}$ than from 〈z〉. Copyright © 2001 John Wiley & Sons, Ltd.
Investigation of the electrostatic forces in scanning probe microscopy at low bias voltages
Authors: Patil Shivprasad , Dharmadhikari C. V. 
Published: August 2002

AbstractThe electrostatic force between a gold tip and an atomically flat highly oriented pyrolytic graphite substrate has been measured as a function of tip– sample separation distance for low bias voltages (<1 v). The experiments involve phase‐sensitive detection of the reflected laser beam off a stiff oscillating cantilever as it approaches the sample. The results are compared with the theoretical model in which the tip– sample geometry is described by confocal hyperboloids of revolution. The general behaviour of the force curve was found to be in agreement with theoretical expectations only for distances of >600 Å. The deviations at smaller distances probably could be due to extraneous material such as graphite nanoflakes or a conducting liquid column present between tip and sample. The results have direct bearing on understanding the interaction forces in scanning probe microscopy techniques in which tip– sample junctions are biased. Copyright © 2002 John Wiley & Sons, Ltd.
XPS of chemically modified low‐density polyethylene surfaces: observations on curve‐fitting the C 1s spectrum
Authors: Briggs D. , Fairley N. 
Published: August 2002

AbstractThe curve‐fitting of the complex C 1s envelopes (obtained under high‐energy‐resolution XPS conditions) resulting from the surface chemical modification of low‐density polyethylene has been investigated. The main problem is modelling of the dominant, asymmetric component due to unmodified hydrocarbon. Two approaches have been compared, namely the use of a full (four‐component) vibrational progression or a single peak with a lineshape recently introduced by Gelius. As well as goodness of fit criteria, the agreement between the measured O 1s intensity and that predicted from the intensities of the high‐binding‐energy C 1s components (from oxygen‐containing functional groups) was used in the assessment. Under the relatively low‐level, but practically relevant, modification conditions studied, the two approaches are equally effective. However, they can give rise to significant differences in the relative intensities of high‐binding‐energy components. Broadening of the various components as a function of treatment also has been studied. Copyright © 2002 John Wiley & Sons, Ltd.
Use of the equivalence approach in reproductive health clinical trials
Authors: Piaggio Gilda , Pinol Alain P. Y. 
Published: August 2002

AbstractAn equivalence trial is appropriate when it is desired to demonstrate equivalence between two treatments, regimens or interventions (methods) or non‐inferiority of a new one compared to a standard one. The conduct of an equivalence trial requires different techniques during design and analysis compared to a superiority trial. The existing formulae for sample size calculation to demonstrate equivalence between two methods using the confidence interval approach are reviewed. The establishment of the margin of equivalence and the choice of the type of test are discussed. Plots of sample sizes required to demonstrate equivalence in the case of binary outcomes are presented for values of proportions and margins of equivalence common in the reproductive health field. Examples are given of method comparisons in the reproductive health field in which the relevant question is to demonstrate non‐inferiority. The approach to equivalence is described in the trials included in three published systematic reviews in which these comparisons were conducted, addressing the statement of hypotheses, sample size calculation and the interpretation of results. The use of the conventional superiority approach to design equivalence trials has led to underpowered trials to show equivalence within clinical relevant margins. The analysis and interpretation of results from such trials has resulted in conclusions of equivalence based on lack of significance. We draw attention to the lack of awareness of the appropriate techniques for equivalence trials among researchers in the field of reproductive health. Finally, the issue of interim analyses and stopping rules in equivalence trials is addressed. Copyright © 2001 John Wiley & Sons, Ltd.
Analysis of mixed categorical data in 2×K contingency tables
Authors: Gautam Shiva 
Published: August 2002

Abstract2×K contingency tables having both ordinal and nominal categories are often encountered in various types of studies. Such data are referred to as ‘mixed’ categorical data in this article. To apply a method for ordered categorical data one has to discard the nominal categories, and to apply a method for nominal categories one has to discard the ordering information inherent in the ordered categories. Therefore, investigators often either discard observations in nominal categories or discard the ordering of the categories before analysing such data. Some information will be lost in both approaches. A method for analysing data in 2×K ‘mixed’ tables is proposed in this paper which can be considered as an extension of well known methods for nominal and ordered categories. The proposed method utilizes observations in the nominal categories as well as the ordering information. If all the categories were ordered then the proposed method reduces to the trend test, and if all the categories were nominal then the proposed method reduced to Pearson's chi‐square test. Copyright © 2002 John Wiley & Sons, Ltd.
Impact of missing data due to drop‐outs on estimators for rates of change in longitudinal studies: a simulation study
Authors: Touloumi G. , Babiker A. G. , Pocock S. J. , Darbyshire J. H. 
Published: August 2002

AbstractMany cohort studies and clinical trials are designed to compare rates of change over time in one or more disease markers in several groups. One major problem in such longitudinal studies is missing data due to patient drop‐out. The bias and efficiency of six different methods to estimate rates of changes in longitudinal studies with incomplete observations were compared: generalized estimating equation estimates (GEE) proposed by Liang and Zeger (1986); unweighted average of ordinary least squares (OLSE) of individual rates of change (UWLS); weighted average of OLSE (WLS); conditional linear model estimates (CLE), a covariate type estimates proposed by Wu and Bailey (1989); random effect (RE), and joint multivariate RE (JMRE) estimates. The latter method combines a linear RE model for the underlying pattern of the marker with a log‐normal survival model for informative drop‐out process. The performance of these methods in the presence of missing data completely at random (MCAR), at random (MAR) and non‐ignorable (NIM) were compared in simulation studies. Data for the disease marker were generated under the linear random effects model with parameter values derived from realistic examples in HIV infection. Rates of drop‐out, assumed to increase over time, were allowed to be independent of marker values or to depend either only on previous marker values or on both previous and current marker values. Under MACR all six methods yielded unbiased estimates of both group mean rates and between‐group difference. However, the cross‐sectional view of the data in the GEE method resulted in seriously biased estimates under MAR and NIM drop‐out process. The bias in the estimates ranged from 30 per cent to 50 per cent. The degree of bias in the GEE estimates increases with the severity of non‐randomness and with the proportion of MAR data. Under MCAR and MAR all the other five methods performed relatively well. RE and JMRE estimates were more efficient(that is, had smaller variance) than UWLS, WLS and CL estimates. Under NIM, WLS and particularly RE estimates tended to underestimate the average rate of marker change (bias≈10 per cent). Under NIM, UWLS, CL and JMRE performed better in terms of bias (3–5 per cent) with the JMRE giving the most efficient estimates. Given that markers are key variables related to disease progression, missing marker data are likely to be at least MAR. Thus, the GEE method may not be appropriate for analysing such longitudinal marker data. The potential biases due to incomplete data require greater recognition in reports of longitudinal studies. Sensitivity analyses to assess the effect of drop‐outs on inferences about the target parameters are important. Copyright © 2001 John Wiley & Sons, Ltd.
Quantifying heterogeneity in a meta‐analysis
Authors: Higgins Julian P. T. , Thompson Simon G. 
Published: August 2002

AbstractThe extent of heterogeneity in a meta‐analysis partly determines the difficulty in drawing overall conclusions. This extent may be measured by estimating a between‐study variance, but interpretation is then specific to a particular treatment effect metric. A test for the existence of heterogeneity exists, but depends on the number of studies in the meta‐analysis. We develop measures of the impact of heterogeneity on a meta‐analysis, from mathematical criteria, that are independent of the number of studies and the treatment effect metric. We derive and propose three suitable statistics: H is the square root of the χ2 heterogeneity statistic divided by its degrees of freedom; R is the ratio of the standard error of the underlying mean from a random effects meta‐analysis to the standard error of a fixed effect meta‐analytic estimate, and I2 is a transformation of H that describes the proportion of total variation in study estimates that is due to heterogeneity. We discuss interpretation, interval estimates and other properties of these measures and examine them in five example data sets showing different amounts of heterogeneity. We conclude that H and I2, which can usually be calculated for published meta‐analyses, are particularly useful summaries of the impact of heterogeneity. One or both should be presented in published meta‐analyses in preference to the test for heterogeneity. Copyright © 2002 John Wiley & Sons, Ltd.
A method for the analysis of repeated binary outcomes in randomized clinical trials with non‐compliance
Authors: Sato Tosiya 
Published: August 2002

AbstractWhen analysing repeated binary data from randomized trials, the model‐based approaches, such as generalized estimating equations, are frequently used. Such methods ignore compliance information and give the model‐based intention‐to‐treat estimate of treatment effect. In this paper, the design‐based (randomization‐based) semi‐parametric estimation procedure is given in the estimation of causal risk difference. The resulting risk difference estimator is interpreted as an extension of the instrumental variables estimator for a binary outcome which has the causal interpretation. Extension of the proposed method to stratified analysis is given for data from stratified randomization or meta‐analysis. It yields a Mantel–Haenszel type risk difference estimator. As a special case of stratified analysis, the pattern mixture model which stratifies the data by pattern of missing data is performed. Application of the proposed method to a trial in which endpoints were the occurrences of fever over three courses is provided. The same ideas are applied to the causal risk ratio estimation. Copyright © 2001 John Wiley & Sons, Ltd.
Incremental net benefit in randomized clinical trials
Authors: Willan Andrew R. , Lin D. Y. 
Published: August 2002

AbstractThere are three approaches to health economic evaluation for comparing two therapies. These are (i) cost minimization, in which one assumes or observes no difference in effectiveness, (ii) incremental cost‐effectiveness, and (iii) incremental net benefit. The latter can be expressed either in units of effectiveness or costs. When analysing data from a clinical trial, expressing incremental net benefit in units of cost allows the investigator to examine all three approaches in a single graph, complete with the corresponding statistical inferences. Furthermore, if costs and effectiveness are not censored, this can be achieved using common two‐sample statistical procedures. The above will be illustrated using two examples, one with censoring and one without. Copyright © 2001 John Wiley & Sons, Ltd.