bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combination of Fragmental and Topological Descriptors for QSPR Estimations of Boiling Temperature
Authors: Tsygankova Irina G. 
Published: November 2004

AbstractThe novel QSPR equation for estimation of physicochemical properties of organic substances is proposed. This equation includes contributions depending on the counts of bonds and nonadditive contribution. The nonadditive term is represented as an explicit function of topological distances on the line graph of molecules. The original mathematical form for description of nonadditive contribution is suggested. The application of the derived equation to estimation of normal boiling temperatures for the saturated hydrocarbons (total number of compounds n=198; correlation coefficient r=0.9966; mean square deviation σ=3.4 K) has proved the effectiveness of the proposed approach. The modification of correlation equation is made for estimations of normal boiling temperatures for substances with OH and NH2 groups (n =139; r=0.9971; σ=3.9 K).
A thin chip microsprayer system coupled to Fourier transform ion cyclotron resonance mass spectrometry for glycopeptide screening
Authors: Bindila Laura , Froesch Martin , Lion Niels , Vukelić Željka , Rossier Joël S. , Girault Hubert H. , Peter‐Katalinić Jasna , Zamfir Alina D. 
Published: November 2004

AbstractA thin polymer microchip was coupled with a Fourier transform ion cyclotron resonance (FTICR) 9.4 T mass spectrometer and the method was optimized in negative ion mode for glycopeptide screening. The interface between the polymer microchip and FTICR mass spectrometer consists of an in‐laboratory conceived and designed mounting system that exhibits robust and controllable alignment of the chip toward the inlet of the mass spectrometer. The particular attribute of the polymer chip coupled to the FTICR mass spectrometer, to achieve an increase in ionization efficiency and sensitivity under the premise of high mass accuracy of detection, is highlighted by the large number of major and minor glycopeptide structures detected and identified in highly heterogeneous mixtures obtained from urine matrices. Glycoforms expressing various saccharide chain lengths ranging from tri‐ to dodecasaccharide, bearing up to three sialic acid moieties, could be detected and assigned based on the accuracy of the mass measurement (average mass deviation below 6 ppm) of their molecular ions. (–)Thin chipESI‐FTICRMS is a potent novel system for glycomic screening of complex mixtures, as demonstrated for identification of singly sialylated O‐glycosylated amino acids and peptides from urine matrices, and could be considered for general applicability in the glycoanalytical field. Copyright © 2004 John Wiley & Sons, Ltd.
Sand exchange between groyne‐field beaches and the navigation channel of the Dutch Rhine: the impact of navigation versus river flow
Authors: Ten Brinke Wilfried B. M. , Schulze Floris H. , van Der Veer Peter 
Published: November 2004

AbstractThe morphodynamics of groyne‐field beaches along the Dutch Rhine was studied from in situ measurements of hydrodynamics and sand transport, aerial photographs, and bed‐level time series. From the analyses, it appeared that groyne‐field beaches experience an alternation of periods of erosion and deposition. The erosion is due to navigation at low to moderate discharge; the deposition is due to floods. On a time scale of a few decades, periods of erosion and deposition are in equilibrium. Navigation‐induced erosion is mainly due to vessels >60 m. The impact of passing vessels on the currents near the banks and the erosion of the beaches increases as underwater volume increases. Individually, loaded barge‐tows have the greatest influence on groyne‐field hydrodynamics and sand transport. On a yearly basis, however, the relatively strong influence of push towing is superseded by the higher frequency of passing motorized vessels. The erosion on a yearly basis, therefore, is driven by the effects of the large motorized vessels. The effects of push towing are negligible.Underwater volume and passing distance from the bank are the most important parameters of passages, insofar as their effect on groyne‐field beaches is concerned. The effect of underwater volume is clearly reflected in the different behaviour of groyne‐field beaches on the north and south banks. Loaded vessels sailing along the south bank from Rotterdam to Germany have a much greater effect on the beaches on the south bank than do returning vessels, often empty or partly loaded, on the beaches of the north bank. As a result, beach erosion on the south bank is twice as pronounced as the erosion on the north bank. Remarkably, the greater erosion of the beaches observed on the south bank was compensated by a similarly larger deposition during the flood of 1998.The impact of navigation on groyne‐field beach erosion increased strongly from 1970 to 2001, and probably will have doubled from 1970 to 2010. Copyright © 2004 John Wiley & Sons, Ltd.
Making sustainable development evaluations work
Authors: Becker Joanna 
Published: November 2004

AbstractThe number of sustainable development evaluation methods has proliferated during the last few years. However, they are often time consuming and expensive to conduct, making reiteration, a crucial part of assessing progress, an unappealing and difficult task. Making the results comprehensible and meaningful to the public is also challenging but essential if evaluations are to be translated into policy and action. Moreover, although such evaluations are important in assessing progress towards sustainable development, it may be hard to make them responsive to change, which is synonymous with the concept of development. Change includes both the conditions being assessed and the techniques that are used.This paper explores the crucial elements for making sustainable development evaluations work using the Bellagio principles as a framework to identify tools that can be used to implement them. These principles are interrelated and taken together can help ensure the effectiveness of sustainable development evaluations. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
Monte‐Carlo program for simulating segregation and diffusion utilizing chemical potential calculations
Authors: Joubert H. D. , Swart H. C. , Terblans J. J. 
Published: November 2004

AbstractThe surface segregation phenomenon was simulated by means of a Chemical Potential Monte‐Carlo (CPMC) model, which is based on the Darken model. The chemical potential equations are rewritten to include the segregation energy associated with the surface layer. Simulations involving the change in chemical potential are performed on a two‐dimensional matrix containing two elements: the solute and the solvent elements. A random selection of an atom inside the matrix initiates the model. The change in chemical potential due to an atomic jump of a randomly selected atom to an adjacent layer is calculated. The largest change in chemical potential directs the atomic motion, complying with the conditions associated with lowering of the Gibbs free energy. Inclusion of the segregation energy (for jumps involving the surface layer) limits the number of atomic jumps from the surface layer to the bulk. Simulated segregation profiles generated by the CPMC model were compared with profiles calculated with both the modified Darken and Fick models. These profiles show that the CPMC model successfully describes both the kinetic and equilibrium conditions associated with surface segregation. Copyright © 2004 John Wiley & Sons, Ltd.
Score tests for dose effect in the presence of non‐responders
Authors: Luo Xiaohui , Boos Dennis D. , Tamura Roy N. 
Published: November 2004

AbstractWhen only a certain proportion of subjects respond to treatment (‘responders’) or may never experience an event of interest (thus ‘cured’), mixture models often lead to increased understanding of the treatment or disease process. This paper focuses on hypothesis testing in a dose–response framework and shows that increased power is possible by using a mixture model where both the logit of the response rate and the response mean are linear functions of the dose level. Three score tests are developed for testing an overall effect and permutation methods are used to control the type I error. Extensive simulations establish the power properties of the tests and show that our proposed score test has the best performance. The approach is illustrated by a multi‐country clinical trial of rapid acting Intramuscular Olanzapine. Copyright © 2004 John Wiley & Sons, Ltd.
A new parametric model for survival data with long‐term survivors
Authors: Shao Quanxi , Zhou Xian 
Published: November 2004

AbstractWe develop a new parametric model using the three‐parameter Burr XII distribution for the analysis of survival data with long‐term survivors, which includes the previous Weibull mixture model as a special case. The new model is applied to the analysis of a set of leukaemia data for which previous attempts in the literature using traditional parametric models were unsatisfactory due to lack of fit. It is shown that the new model improves the fit to the leukaemia data significantly and is thus capable of providing more credible answers to a variety of statistical inference problems that are of interest to medical researchers and practitioners. Copyright © 2004 John Wiley & Sons, Ltd.
Modelling neuromotor ratings with floor‐effects
Authors: Gasser Theo , Rousson Valentin 
Published: November 2004

AbstractAssociated movements (AMs) are a classical diagnostic tool to assess differences between normal children and children with some motor dysfunction. This paper presents a methodology to produce age‐ and gender‐dependent reference‐curves for AMs of normal children, for various tasks of a test battery. Data available consist of separate ratings of duration and extent of AMs, which are ordinal quantities with few levels. Other problems are severe age‐ and gender‐dependent floor‐effects (as well as some ceiling‐effects), leaving little information for analysis at older ages. To get a better scale, we combined the two ordinal ratings into one meaningful and quasi‐continuous quantity referred to as intensity of AMs. In order to solve problems due to floor‐effects, ceiling‐effects and discreteness, we assumed left‐ , right‐ and interval‐censored values, respectively. We considered a censored regression problem and postulated a truncated normal distribution for the non‐censored values (after an appropriate transformation of the data). Using Wei and Tanner's poor man's data augmentation algorithm, together with the technique of linear mixed effects modelling, useful reference‐curves could be produced. In contrast to the cumulative probabilities approach for ordinal data, our methodology allows the calculation of individual age‐ and gender‐standardized values, which puts us in a position to investigate numerous scientific questions. Copyright © 2004 John Wiley & Sons, Ltd.
Using the area under the curve to reduce measurement error in predicting young adult blood pressure from childhood measures
Authors: Cook Nancy R. , Rosner Bernard A. , Chen Wei , Srinivasan Sathanur R. , Berenson Gerald S. 
Published: November 2004

AbstractTracking correlations of blood pressure, particularly childhood measures, may be attenuated by within‐person variability. Combining multiple measurements can reduce this error substantially. The area under the curve (AUC) computed from longitudinal growth curve models can be used to improve the prediction of young adult blood pressure from childhood measures. Quadratic random‐effects models over unequally spaced repeated measures were used to compute the area under the curve separately within the age periods 5–14 and 20–34 years in the Bogalusa Heart Study. This method adjusts for the uneven age distribution and captures the underlying or average blood pressure, leading to improved estimates of correlation and risk prediction. Tracking correlations were computed by race and gender, and were approximately 0.6 for systolic, 0.5–0.6 for K4 diastolic, and 0.4–0.6 for K5 diastolic blood pressure. The AUC can also be used to regress young adult blood pressure on childhood blood pressure and childhood and young adult body mass index (BMI). In these data, while childhood blood pressure and young adult BMI were generally directly predictive of young adult blood pressure, childhood BMI was negatively correlated with young adult blood pressure when childhood blood pressure was in the model. In addition, racial differences in young adult blood pressure were reduced, but not eliminated, after controlling for childhood blood pressure, childhood BMI, and young adult BMI, suggesting that other genetic or lifestyle factors contribute to this difference. Copyright © 2004 John Wiley & Sons, Ltd.
Box–Cox transformation of left‐censored data with application to the analysis of coronary artery calcification and pharmacokinetic data
Authors: Han Cong , Kronmal Richard 
Published: November 2004

AbstractBox–Cox transformation is investigated for regression models for left‐censored data. Examples are provided using coronary calcification data from the Multi‐Ethnic Study of Atherosclerosis and pharmacokinetic data of a nicotine nasal spray. Copyright © 2004 John Wiley & Sons, Ltd.
Conditional mixed models adjusting for non‐ignorable drop‐out with administrative censoring in longitudinal studies
Authors: Li Jingjin , Schluchter Mark D. 
Published: November 2004

AbstractIn this paper, a class of conditional mixed models is proposed to adjust for non‐ignorable drop‐out, while also accommodating unequal follow‐up due to staggered entry and administrative censoring in longitudinal studies. Conditional linear and quadratic models which model subject‐specific slopes as linear or quadratic functions of the time‐to‐drop‐out, as well as pattern mixture models are both special cases of this approach. We illustrate these models and compare them with the usual maximum likelihood approach assuming ignorable drop‐out using data from a multi‐centre randomized clinical trial of renal disease. Simulations under various scenarios where the drop‐out mechanism is ignorable and non‐ignorable are employed to evaluate the performance of these models. Copyright © 2004 John Wiley & Sons, Ltd.
A Welch‐type test for homogeneity of contrasts under heteroscedasticity with application to meta‐analysis
Authors: Kulinskaya E. , Dollinger M. B. , Knight E. , Gao H. 
Published: November 2004

AbstractA common problem that arises in the meta‐analysis of several studies, each with independent treatment and control groups, is to test for the homogeneity of effect sizes without the assumptions of equal variances of the treatment and the control groups and of equal variances among the separate studies. A commonly used test statistic, frequently denoted as Q, is the weighted sum of squares of the differences of the individual effect sizes from the mean effect size, with weights inversely proportional to the variances of the effect sizes. The primary contributions of this article are the presentation of improved and very accurate approximations to the distributions of the Q statistic when the effect size is a linear contrast such as the difference between the treatment and control means. Our improved approximation to the distribution of Q under the null hypothesis is based on a multiple of an F‐distribution; its use yields a substantial reduction in the type I error rate of the homogeneity test. Our improved approximation to the distribution of Q under an alternative hypothesis is based on a shift of a chi‐square distribution; its use allows for much greater accuracy in the computation of the power of the homogeneity test. These two improved approximate distributions are developed using the Welch methodology of approximating the moments of Q by the use of multivariate Taylor expansions. The quality of these approximations is studied by simulation.A secondary contribution of this article is a study of how best to combine the variances of the treatment and control groups (needed for the calculation of weights in the Q statistic). Our conclusion, based on simulations, is that use of pooled variances can result in substantially erroneous conclusions. Copyright © 2004 John Wiley & Sons, Ltd.
Comparison of Bayesian model averaging and stepwise methods for model selection in logistic regression
Authors: Wang Duolao , Zhang Wenyang , Bakhai Ameet 
Published: November 2004

AbstractLogistic regression is the standard method for assessing predictors of diseases. In logistic regression analyses, a stepwise strategy is often adopted to choose a subset of variables. Inference about the predictors is then made based on the chosen model constructed of only those variables retained in that model. This method subsequently ignores both the variables not selected by the procedure, and the uncertainty due to the variable selection procedure. This limitation may be addressed by adopting a Bayesian model averaging approach, which selects a number of all possible such models, and uses the posterior probabilities of these models to perform all inferences and predictions. This study compares the Bayesian model averaging approach with the stepwise procedures for selection of predictor variables in logistic regression using simulated data sets and the Framingham Heart Study data. The results show that in most cases Bayesian model averaging selects the correct model and out‐performs stepwise approaches at predicting an event of interest. Copyright © 2004 John Wiley & Sons, Ltd.
Physicochemical, Thermal, Morphological and Pasting Properties of Starches from some Indian Black Gram (Phaseolus mungo L.) Cultivars
Authors: Singh Narpinder , Kaur Maninder , Sandhu Kawaljit Singh , Guraya Harmeet Singh 
Published: November 2004

AbstractThe starches separated from thirteen different black gram cultivars were investigated for physicochemical, thermal, morphological and pasting properties. Amylose content, swelling power, solubility and water binding capacity of starches ranged between 30.2–34.6%, 16.0–22.3 g/g, 14.8–17.3% and 73.5–84.5%, respectively. The diameter of starch granules, measured using a laser‐light scattering particle‐size analyzer, varied from 12.8 to 14.3 μm in all black gram starches. The shape of starch granules varied from oval to elliptical. The transition temperatures (To, Tp and Tc) and enthalpy of gelatinization (ΔHgel) determined using differential scanning calorimetry, ranged between 66.1–71.3, 71.0–76.2, 75.9–80.4°C and 6.7–9.4 J/g, respectively. Pasting properties of starches measured using the Rapid Visco Analyser (RVA) also differed significantly. Pasting temperature, peak viscosity, trough, breakdown, final viscosity and setback were between 75.8–80.3°C, 422–514, 180–311, 134–212, 400–439 and 102–151 Rapid Visco Units (RVU), respectively. Turbidity values of gelatinized starch pastes increased during refrigerated storage. The relationships between different properties were also determined using Pearson correlation coefficients. Amylose content showed a positive correlation with swelling power, turbidity and granule diameter. Swelling power showed a negative correlation with solubility and setback. To, Tp and Tc showed positive correlation with turbidity, pasting temperature and were negatively correlated to peak and breakdown viscosity.
Unimolecular rectifiers and prospects for other unimolecular electronic devices
Authors: Metzger Robert M. 
Published: November 2004

AbstractWe briefly review the progress towards useful one‐molecule electronic devices, toward the ultimate reduction in integrated circuit sizes, and then describe five unimolecular rectifiers, or one‐way conductors of electrical current: γ‐hexadecylquinolinium tricyanoquinodimethanide, an acetyl sulfoxide derivative of this compound, 2,6‐di[dibutylamino‐phenylvinyl]‐1‐butylpyridinium iodide, dimethylanilino‐aza[C60]fullerene, and a new fullerene derivative. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 291–304; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20015
Homochirality and life
Authors: Fujii Noriko , Saito Takeshi 
Published: November 2004

AbstractBefore the emergence of life, left‐handed amino acids (L‐enantiomers) were selected and right‐handed amino acids (D‐enantiomers) were eliminated on the primal earth. Nevertheless, with the progress of analytical methods, D‐amino acids have recently been found in higher order living organisms in the form of free amino acids, peptides, and proteins. Free D‐amino acids have numerous physiological functions. D‐amino acids containing animal peptides are well known as opioid peptides. D‐amino acids in protein are related to aging. In this review, we describe the D‐amino acids that are present and function as D‐amino acid biosystems in our bodies. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 267–278; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20020
Butanol fermentation research: upstream and downstream manipulations
Authors: Ezeji Thaddeus C. , Qureshi Nasib , Blaschek Hans P. 
Published: November 2004

AbstractAn overview of advances in acetone–butanol fermentation research is presented with specific reference to the history of acetone–butanol fermentation, genetic manipulation of the butanol‐producing Clostridium beijerinckii NCIMB 8052, as well as upstream and downstream processing. Specific reference is made to the development of the hyperamylolytic, hyper‐“butanolagenic” C. beijerinckii BA101 strain. Amylolytic enzyme production by C. beijerinckii BA101 was 1.8‐ and 2.5‐fold greater than that of the C. beijerinckii NCIMB 8052 strain grown in starch and glucose, respectively. We confirmed the presence of a phosphoenolpyruvate (PEP)‐dependent phosphotransferase system (PTS) associated with cell extracts of C. beijerinckii BA101 by glucose phosphorylation by PEP and ATP‐dependent glucose phosphorylation. It was found that C. beijerinckii BA101 was defective in PTS activity and that it compensates for this defect with enhanced glucokinase activity, resulting in an ability to transport and utilize glucose during the solventogenic stage. The principal problem associated with acetone–butanol fermentation by C. beijerinckii or C. acetobutylicum is butanol toxicity/inhibition to the culture. To solve this problem, we have attempted various alternative in situ/online techniques of butanol removal including membrane‐based systems such as pervaporation, liquid–liquid extraction, and gas stripping. We found that gas stripping and pervaporation appear to be the most promising of the in situ acetone–butanol fermentation and recovery techniques but, in terms of cost‐effective industrial applications, gas stripping appears to be the most promising. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 305–314; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20023