bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical study of the · H reaction with cytosine
Authors: Zhang Hongyu , Liang Qimin , Xia Yueyuan , Zhao Mingwen , Ji Yanju , Song Chen , Liu Xiangdong , Zhang Bingyun 
Published: August 2006

AbstractWe studied three possible reactions of H atom attacking the cytosine, using density functional theory (DFT) calculations. The results indicate that the H atom addition to the N3 site of cytosine is energetically more favorable than to the C5 or C6 site. The reaction of addition to the C6 site has an energy barrier of ∼2.77 kcal/mol, which is ∼2 kcal/mol higher than addition to C5. The energy of C5 H‐adduct radical is also lower than that of C6 H‐adduct radical. From the point of view of both energetics and reaction kinetics, the addition of the H atom to the C5 site is preferred to the addition to the C6 site. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Docking stability and electronic structure of azurin–cytochrome c551 complex system
Authors: Sugiyama Ayumu , Takamatsu Yuichiro , Nishikawa Keigo , Nagao Hidemi , Nishikawa Kiyoshi 
Published: August 2006

AbstractWe investigate the docking structure between cytochrome c551 and azurin proteins by quantum mechanical calculation and molecular dynamics (MD). A model for the docking structure of the cytochrome–azurin complex is presented. We calculate the charge distribution around the active site for each protein and force field parameters to simulate the complex system by MD. We estimate some physical properties, such as binding free energy and the dynamical cross‐correlation map. We discuss the stability of the cytochrome c551–azurin complex system. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Development of a liquid chromatography/tandem mass spectrometry assay for the quantification of PM02734, a novel antineoplastic agent, in dog plasma
Authors: Yin Jianming , Aviles Pablo , Lee William , Ly Carl , Guillen Maria Jose , Munt Simon , Cuevas Carmen , Faircloth Glynn 
Published: August 2006

AbstractA rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay was developed and validated to quantify a novel antineoplastic agent, PM02734, in dog plasma. The method was validated to demonstrate the specificity, limit of quantification (LOQ), accuracy, and precision of measurements. The calibration range for PM02734 was established using PM02734 standards from 0.05 to 100 ng/mL in blank plasma. The dominating ions were doubly charged molecular ions [M+2H]2+ at m/z 740.0 instead of singly charged ones at m/z 1478.4. The selected reaction monitoring (SRM), based on the m/z 740.0 → 212.2 transition, was specific for PM02734, and that based on the m/z 743.8 → 212.2 transition was specific for deuterated PM02734 (the internal standard, IS); no endogenous materials interfered with the analysis of PM02734 and IS from blank plasma. The assay was linear over the concentration range 0.05–100 ng/mL. In terms of sensitivity of assay 0.05 ng/mL is a very low LLOQ, especially considering PM02734 is a peptide. The correlation coefficients for the calibration curves ranged from 0.9990 to 0.9999. The mean intraday and interday accuracies for all calibration standards (n = 9) ranged from 93 to 111% (≤11% bias) in dog plasma, and the mean interday precision for all calibration standards was less than 6.4%. The mean intra‐ and interday assay accuracy for all quality control replicates in dog plasma (n = 9), determined at each QC level throughout the validated runs, ranged from 85–111% (≤15% bias) and from 99–109% (≤9% bias), respectively. The mean intra‐ and interday assay precision was less than 12.1 and 13.3% for all QC levels, respectively. The assay has been used to support preclinical pharmacokinetic (PK) and toxicokinetic studies. The results showed that preclinical samples could be monitored for PM02734 up to 168 h after dosing, which allowed us to identify multiple elimination phases and accurately estimate PK information. Copyright © 2006 John Wiley & Sons, Ltd.
Application of hollow fiber supported liquid membrane extraction to the simultaneous determination of pesticide residues in vegetables by liquid chromatography/mass spectrometry
Authors: Romero‐González Roberto , Pastor‐Montoro Elena , Martínez‐Vidal José Luis , Garrido‐Frenich Antonia 
Published: August 2006

AbstractA new analytical procedure using a hollow fiber supported liquid membrane (HFSLM) has been developed for the simultaneous determination of pesticide residues in vegetables by liquid chromatography (LC) coupled with electrospray mass spectrometry (MS). The extraction technique requires minimal sample preparation and solvent consumption. Optimum extraction conditions have been evaluated with respect to sample pH, ionic strength, liquid membrane composition, extraction time, stirring rate and acceptor composition. The extraction method has been validated for matrices such as cucumber, tomato and pepper, indicating that cucumber can be selected as representative matrix for routine analysis of these food commodities. Linear ranges of pesticides in vegetable samples were 10 to 200 µg/kg, and the repeatability of the method was less than 20% for the lowest calibration point. The limits of detection ranged from 0.06 to 2.7 µg/kg and the limits of quantification from 0.2 to 9.0 µg/kg, which were low enough to determine the pesticide residues at concentrations below or equal to the maximum residue levels (MRLs) specified by European Union. The method was finally applied to the determination of more than 20 pesticides in market vegetable samples and the concentrations found in these samples were always lower than the MRLs. This new approach can be considered as a powerful alternative to the traditional extraction techniques. Copyright © 2006 John Wiley & Sons, Ltd.
Multiple sclerosis is linked to Epstein‐Barr virus infection
Authors: Haahr Sven , Höllsberg Per 
Published: August 2006

AbstractThe aetiology and pathogenesis of MS are unknown, but environmental agents, genetic susceptibility and stochastic events are likely to be involved. In order to evaluate the possibility that MS is linked to EBV infection, we here evaluate studies on MS‐ and EBV‐epidemiology, prospective and retrospective analysis of EBV‐serology, investigations of EBV DNA sequences in blood and tissues, specificity of antibodies in oligoclonal bands in MS patients and results from antiviral chemotherapy of MS patients. It could be demonstrated that EBV is complying with the epidemiological observations in MS and that all MS patients are seropositive to EBV in contrast to healthy controls. Importantly, despite difficulties in diagnosing child‐MS, the vast majority of these patients are also EBV seropositive. In contrast to control groups, recent EBV infections have never been observed in children or adults with MS. Further prospective studies indicate a 2.8 times higher tendency for development of MS after infectious mononucleosis. In MS patients, unbiased analyses pull out EBV antigens as high‐affinity targets for the antibodies in the oligoclonal bands. Humans are the exclusive natural host for EBV, a finding that may explain why MS is unique to humans. Together these unique observations strongly suggest a linkage between MS and EBV infection. Infection by EBV offers numerable mechanisms to perturb the immune system, including mimicry and superantigen induction, which may potentially participate in the disease mechanisms. In contrast, studies demonstrating higher IgG titres and occurrence of viral DNA in serum/plasma are likely to reflect a consequence of the disease. An explanation for a potential role of respiratory diseases in MS is discussed. It is concluded that the ultimate test to the hypothesis of MS and EBV is the development and application of an EBV vaccine, which is predicted to eradicate the disease. Copyright © 2006 John Wiley & Sons, Ltd.
Virus discovery by sequence‐independent genome amplification
Authors: Ambrose Helen E. , Clewley Jonathan P. 
Published: August 2006

AbstractGenome sequences from several blood borne and respiratory viruses have recently been recovered directly from clinical specimens by variants of a technique known as sequence‐independent single primer amplification. This and related methods are increasingly being used to search for the causes of diseases of presumed infectious aetiology, but for which no agent has yet been found. Other methods that do not require prior knowledge of the genome sequence of any virus that may be present in the patient specimen include whole genome amplification, random PCR and subtractive hybridisation and differential display. This review considers the development and application of these techniques. Copyright © 2006 John Wiley & Sons, Ltd.
Stability radii of infinite dimensional systems with stochastic uncertainty and their optimization
Authors: Kada M. , E. Rebiai S. 
Published: August 2006

AbstractIn this paper we consider infinite dimensional systems which are subjected to stochastic structured multiperturbations. We first characterize the stability radii of these systems in terms of a Lyapunov equation and the corresponding Lyapunov inequalities. Then we investigate the problem of maximizing the stability radius by linear state feedback. We show that the supremal achievable stability radius can be determined via the resolution of a parametrized Riccati equation. Illustrative examples are included. Copyright © 2006 John Wiley & Sons, Ltd.
Support vector machines‐based generalized predictive control
Authors: Iplikci S. 
Published: August 2006

AbstractIn this study, we propose a novel control methodology that introduces the use of support vector machines (SVMs) in the generalized predictive control (GPC) scheme. The SVM regression algorithms have extensively been used for modelling nonlinear systems due to their assurance of global solution, which is achieved by transforming the regression problem into a convex optimization problem in dual space, and also their higher generalization potential. These key features of the SVM structures lead us to the idea of employing a SVM model of an unknown plant within the GPC context. In particular, the SVM model can be employed to obtain gradient information and also it can predict future trajectory of the plant output, which are needed in the cost function minimization block. Simulations have confirmed that proposed SVM‐based GPC scheme can provide a noticeably high control performance, in other words, an unknown nonlinear plant controlled by SVM‐based GPC can accurately track the reference inputs with different shapes. Moreover, the proposed SVM‐based GPC scheme maintains its control performance under noisy conditions. Copyright © 2006 John Wiley & Sons, Ltd.
Novel down link rain fade mitigation technique for Ka‐band multibeam systems
Authors: Majithiya Parimal , Sisodia A. K. , Muralidhar V. , Garg V. K. 
Published: August 2006

AbstractRain fades at Ka‐Band degrades the link quality and performance significantly. Several rain fade mitigation techniques for Ka‐band satellite systems are being investigated to improve the channel capacity. Methods such as power control and adaptive waveform techniques have been proposed for use in the uplink as they are capable of straightforward implementation. A novel down link power control technique for multi‐beam Ka‐band system has been proposed in this paper. It is based on the use of multi‐port amplifier, which is commonly used for dynamic power sharing of the beams depending upon the traffic. Payload architecture for multi‐beam coverage using multi‐port amplifiers has been designed for the proposed technique. The simulation results to compensate for the rain fade attenuation of one beam by sharing the unused power from other beams have been presented Copyright © 2006 John Wiley & Sons, Ltd.
Biostatisticians, biostatistical science and the future
Authors: Zelen Marvin 
Published: August 2006

AbstractBiostatistical Science is in a ‘golden period’. The definition of Biostatistical Science is the application of statistics, probability, mathematics and computing to advance our understanding of the subject matter in the biomedical sciences. Our field is experiencing unparallel developments due of the advances in communication and computing. We are becoming more global, we have resources which can expand educational opportunities for distant learning; the growth of quantitative methods in the biomedical sciences has made biostatistical science a key component in many research areas. What about the future? Are we receptive to change as many new scientific areas expand? Will the interaction between academia and industry likely to grow—especially in the training of future practitioners of biostatistical science. This paper discusses some of challenges facing our profession if we are to continue to be relevant in the biomedical sciences. Copyright © 2006 John Wiley & Sons, Ltd.
The merits of breaking the matches: a cautionary tale
Authors: Donner Allan , Taljaard Monica , Klar Neil 
Published: August 2006

AbstractMatched‐pair cluster randomization trials are frequently adopted as the design of choice for evaluating an intervention offered at the community level. However, previous research has demonstrated that a strategy of breaking the matches and performing an unmatched analysis may be more efficient than performing a matched analysis on the resulting data, particularly when the total number of communities is small and the matching is judged as relatively ineffective.The research concerning this question has naturally focused on testing the effect of intervention. However, a secondary objective of many community intervention trials is to investigate the effect of individual‐level risk factors on one or more outcome variables. Focusing on the case of a continuous outcome variable, we show that the practice of performing an unmatched analysis on data arising from a matched‐pair design can lead to bias in the estimated regression coefficient, and a corresponding test of significance which is overly liberal. However, for large‐scale community intervention trials, which typically recruit a relatively small number of large clusters, such an analysis will generally be both valid and efficient.We also consider other approaches to testing the effect of an individual‐level risk factor in a matched‐pair cluster randomization design, including a generalized linear model approach that preserves the matching, a two‐stage cluster‐level analysis, and an approach based on generalized estimating equations. Copyright © 2006 John Wiley & Sons, Ltd.
Training of the next generation of biostatisticians: a call to action in the U.S.
Authors: DeMets David L. , Stormo Gary , Boehnke Michael , Louis Thomas A. , Taylor Jeremy , Dixon Dennis 
Published: August 2006

AbstractTwo workshops (2001, 2003) were held by the National Institutes of Health (NIH) to examine the need to train more biostatisticians in the U.S. to meet the increasing opportunities in the biomedical research enterprise. The supply of new PhD graduates in biostatistics in the U.S. has been relatively steady for the past two decades while the demand has increased dramatically. These workshops concluded that a renewed effort must be made in the U.S., led in part by the NIH, to add to and expand the existing training programs to increase the supply. This article summarizes those two workshops and their recommendations. Some progress has been made through a new biostatistics training program with emphasis in bioinformatics sponsored by the National Institute of General Medical Sciences (NIGMS). Copyright © 2006 John Wiley & Sons, Ltd.
Covariates‐dependent confidence intervals for the difference or ratio of two median survival times
Authors: Chen Yuh‐Ing , Chang Yu‐Mei 
Published: August 2006

AbstractIn this paper, we are concerned with the estimation of the discrepancy between two treatments when right‐censored survival data are accompanied with covariates. Conditional confidence intervals given the available covariates are constructed for the difference between or ratio of two median survival times under the unstratified and stratified Cox proportional hazards models, respectively. The proposed confidence intervals provide the information about the difference in survivorship for patients with common covariates but in different treatments. The results of a simulation study investigation of the coverage probability and expected length of the confidence intervals suggest the one designed for the stratified Cox model when data fit reasonably with the model. When the stratified Cox model is not feasible, however, the one designed for the unstratified Cox model is recommended. The use of the confidence intervals is finally illustrated with a HIV+ data set. Copyright © 2006 John Wiley & Sons, Ltd.
Confidence intervals for predictive values with an emphasis to case–control studies
Authors: Mercaldo Nathaniel D. , Lau Kit F. , Zhou Xiao H. 
Published: August 2006

AbstractThe accuracy of a binary‐scale diagnostic test can be represented by sensitivity (Se), specificity (Sp) and positive and negative predictive values (PPV and NPV). Although Se and Sp measure the intrinsic accuracy of a diagnostic test that does not depend on the prevalence rate, they do not provide information on the diagnostic accuracy of a particular patient. To obtain this information we need to use PPV and NPV. Since PPV and NPV are functions of both the accuracy of the test and the prevalence of the disease, constructing their confidence intervals for a particular patient is not straightforward. In this paper, a novel method for the estimation of PPV and NPV, as well as their confidence intervals, is developed. For both predictive values, standard, adjusted and their logit transformed‐based confidence intervals are compared using coverage probabilities and interval lengths in a simulation study. These methods are then applied to two case–control studies: a diagnostic test assessing the ability of the e4 allele of the apolipoprotein E gene (ApoE.e4) on distinguishing patients with late‐onset Alzheimer's disease (AD) and a prognostic test assessing the predictive ability of a 70‐gene signature on breast cancer metastasis. Copyright © 2006 John Wiley & Sons, Ltd.
Proportional odds logistic regression—effective means of dealing with limited uncertainty in dichotomizing clinical outcomes
Authors: Valenta Zdenek , Pitha Jan , Poledne Rudolf 
Published: August 2006

AbstractClassifying a measurable clinical outcome as a dichotomous variable often involves difficulty with borderline cases that could fairly be assigned either of the two binary class memberships. In such situations the indicated class membership is often highly subjective and subject to, for instance, a measurement error. In other situations the intermediate level of a three‐level ordinal factor may sometimes be explicitly reserved for cases which could likely belong to either of the two binary classes. Such indefinite readings are often eliminated from the statistical analysis. In this article we review conceptual and methodological aspects of employing proportional odds logistic regression for a three level ordinal factor as a suitable alternative to ordinary logistic regression when dealing with limited uncertainty in classifying clinical outcome as a binary variable. Copyright © 2006 John Wiley & Sons, Ltd.
A deficiency of the odds ratio as a measure of effect size
Authors: Newcombe Robert G. 
Published: August 2006

AbstractThe odds ratio is probably the most widely used measure of association for binary variables. It has many well‐recognized advantages and disadvantages vis‐à‐vis the risk ratio. We demonstrate that for chained or conditional probabilities, odds ratios can behave paradoxically, by failing to show a reinforcement effect that is expressed very clearly when risk ratios are used. Copyright © 2006 John Wiley & Sons, Ltd.
Current status of microplasma research
Authors: Tachibana Kunihide 
Published: August 2006

AbstractMicroscale plasmas of micrometer to millimeter range have been attracting much attention in recent years. Those microplasmas generally operate at high‐pressure regions, including atmospheric pressure, and exhibit characteristics that differ from traditional plasmas at lower pressure regions in their plasma parameters and other parameters originating from their small dimensions. When those characteristics are well combined with the inherent properties of plasmas as reactive, light‐emissive and conductive/dielectric media, there appear a variety of potential applications for nano‐material syntheses, micromachining tools, microchemical analyses, photonic devices and biomaterial processing. In this article, the current status and perspective of microplasma research are reviewed from the viewpoints of plasma generation, diagnostics/simulations and new applications. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Cathode technologies for field emission displays
Authors: Nagao Masayoshi 
Published: August 2006

AbstractTechnologies for the cathode substrate side of field emission displays (FEDs) are briefly described. In addition to electron emitter technologies, evaluation techniques and ways to improve the emission of field emitters are described in detail because these technologies are important for developing practical applications. FEDs will be commercially available within one or two years, and therefore the next generation FEDs beyond these are discussed. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Observation of atmospheric electricity variation signals during underground seismic wave propagation
Authors: Okubo Kan , Sato Shinya , Ishii Takao , Takeuchi Nobunao 
Published: August 2006

AbstractWe have installed an underground electromagnetic observation room in the Hosokura mine in Miyagi Prefecture (Hosokura observation room) to observe the variation in atmospheric electromagnetic signals. In this room, we have set up a large plate electrode to observe signal variation of atmospheric electricity. With this, we have observed co‐seismic electromagnetic phenomena. During the two medium earthquakes that occurred on 27 and 29 February 2004, we observed clear co‐seismic signals in the plate electrode potential variation in the room. A model of the appearance of these signals is examined to explain the observed data. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Local structures and electronic structures of HfON thin films: x‐ray absorption fine structure study and first‐principles calculations
Authors: Kim Sung Kwan , Kim Yangsoo , No Kwangsoo 
Published: August 2006

AbstractThe local structures of HfON thin films were analyzed using an extended x‐ray absorption fine structure (EXAFS) study of the Hf L3‐edge and first‐principles calculations. Depending on their composition and atomic configurations, Hf4O5N2 [coordination number (CN): 6.25], Hf4O2N4 (CN: 5.5) and Hf4O2N4 (CN: 5.0) were suggested as the local structures of HfON thin films. Using the suggested local structures, the electronic structures of HfON thin films were calculated. The variations of the valence band were analyzed with the film composition and compared with the experimental valence band. The optical band gaps of HfON thin films were compared with the calculated values. The transition rate for the optical absorption was suggested as another reason for the band gap difference. Copyright © 2006 John Wiley & Sons, Ltd.