bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating the difference between differences: measurement of additive scale interaction for proportions
Authors: Newcombe Robert G. 
Published: August 2002

AbstractA simple, effective closed‐form method to calculate a confidence interval for the difference between two differences of proportions is proposed. The method is based on the Wilson score interval for the single proportion, and may be used to compare either unpaired or paired differences. It is equally applicable whether cell frequencies are large or small; and coverage properties are favourable. It is easily adapted to give a confidence interval for the treatment effect for a binary outcome in a two‐period cross‐over trial. Copyright © 2001 John Wiley & Sons, Ltd.
Monitoring a clinical trial with multiple hypotheses concerning the treatment effect on a single primary endpoint
Authors: Denne Jonathan S. , Koch Gary G. 
Published: August 2002

AbstractIn a number of clinical trials there is interest in testing more than one hypothesis concerning the treatment effect on a single primary endpoint. For instance, a sponsor of a trial to demonstrate that a test treatment (T) is non‐inferior to an active control (R) may also be interested in showing that T is superior to R, if this is the case. Using theclosed testingmethod for constructing tests of multiple hypotheses which control the multiple level of significance, we provide a framework for testing these hypotheses sequentially during a trial at pre‐planned interim analyses. Copyright © 2001 John Wiley & Sons, Ltd.
Analysis of childhood brain tumour data in New York City using frailty models
Authors: Xue Xiaonan 
Published: August 2002

AbstractThis paper uses frailty models to analyse overall survival and progression‐free survival times for children with a brain tumour. We are interested in how surgery resection affects survival times. We are also interested in how strong a child's progression‐free survival correlates with his/her overall survival and if the association differs with age. Traditionally the frailty is modelled parametrically and a maximum likelihood approach is used to estimate the parameters of interest. However, the result is sensitive to the misspecification of the frailty distribution and the currently developed algorithms for the maximum likelihood approach do not allow the association parameter to depend on covariates. Xue formulates a Poisson regression model and applies an estimating equation approach to obtain a consistent estimate of the covariate effect on survival. This paper extends that approach to obtain consistent and efficient estimates of the association parameter as well as the covariate effect and to allow the association parameter to depend on the covariates. The approach does not require the specification of the frailty distribution. The performance of the method is evaluated through simulation studies. We apply this method to a childhood brain tumour data set in New York City. Copyright © 2001 John Wiley & Sons, Ltd.
An adjustment for a post‐randomization variable in the comparison of two treatments for survival
Authors: Heller Glenn 
Published: August 2002

AbstractA method is proposed to infer the randomized treatment effect on survival after an adjustment for a post‐randomization variable. The post‐randomization variable is made independent of the treatment assignment and is considered a surrogate for baseline prognostic factors. The relationship between the post‐randomization surrogate and baseline prognostic factors for survival is considered smooth, but otherwise unknown. The effect of these factors on survival is modelled using the Cox proportional hazards model with a semi‐parametric relative risk function. Likelihood based estimates and tests for the treatment effect are demonstrated. An example from a randomized clinical trial in cancer illustrates the methodology. Copyright © 2001 John Wiley & Sons, Ltd.
A comparison of generalized linear mixed model procedures with estimating equations for variance and covariance parameter estimation in longitudinal studies and group randomized trials
Authors: Evans Brent A. , Feng Ziding , Peterson Arthur V. 
Published: August 2002

AbstractResponse data in longitudinal studies and group randomized trials are gathered on units that belong to clusters, within which data are usually positively correlated. Therefore, estimates and confidence intervals for intraclass correlation or variance components are helpful when designing a longitudinal study or group randomized trial. Data simulated from both study designs are used to investigate the estimation of variance and covariance parameters from the following procedures: for continuous outcomes, restricted maximum likelihood (REML) and estimating equations (EE); for binary outcomes, restricted pseudo‐likelihood (REPL) and estimating equations (EE). We evaluate these procedures to see which provide valid and precise estimates as well as correct standard errors for the intraclass correlation coefficient or variance components. REML seems the better choice for estimating terms related to correlation for models with normal outcomes, especially in group randomized trial situations. Results for REML and EE are mixed when outcomes are continuous and non‐normal. With binary outcomes neither REPL nor EE provides satisfactory estimation or inference in longitudinal study situations, while REPL is preferable for group randomized trials. Copyright © 2001 John Wiley & Sons, Ltd.
Security in the Ajanta mobile agent system
Authors: Karnik Neeran M. , Tripathi Anand R. 
Published: August 2002

AbstractA mobile agent is an object which can autonomously migrate in a distributed system to perform tasks on behalf of its creator. Security issues in regard to the protection of host resources, as well as the agent themselves, raise significant obstacles in practical applications of the agent paradigm. This article describes the security architecture of Ajanta, a Java‐based system for mobile agent programming. This architecture provides mechanisms to protect server resources from malicious agents, agent data from tampering by malicious servers and communication channels during its travel, and protection of name service data and the global namespace. We present here a proxy based mechanism for secure access to server resources by agents. Using Java's class loader model and thread group mechanism, isolated execution domains are created for agents at a server. An agent can contain three kinds of protected objects: read‐only objects whose tampering can be detected, encrypted objects for specific servers, and a secure append‐only log of objects. A generic authentication protocol is used for all client–server interactions when protection is required. Using this mechanism, the security model of Ajanta enforces protection of namespaces, and secure execution of control primitives such as agent recall or abort. Ajanta also supports communication between agents using RMI, which can be controlled if required by the servers' security policies. Copyright © 2001 John Wiley & Sons, Ltd.
A framework for the development of videogames
Authors: Santelices Raúl A. , Nussbaum Miguel 
Published: August 2002

AbstractA framework is a high‐level solution for the reuse of software pieces, a step forward in simple library‐based reuse, that allows the sharing of not only common functions but also the generic logic of a domain application. It also ensures a better level of quality for the final product, given the fact that an important fraction of the application is already found within the framework and has therefore already been tested. This case study takes the systematic generation of hot‐spot subsystems approach as a reference point to describe the underlying concepts in the design of a framework for the development of 2D action videogames for low‐performance machines. The main goal of this paper is to show the applicability of framework‐based reuse to videogames. Both standard and framework‐based game implementations are compared and the results are analysed. Special attention is paid to the (potential) benefits that the use of frameworks brings to the fulfillment of maintenance tasks along the game's life cycle, a stage that normally consumes most resources in software projects. At the end of the paper, based on the implementation results, this study shows the predicted conditions under which building a framework is cost effective for the development of videogames similar to the ones from the studied domain. Copyright © 2001 John Wiley & Sons, Ltd.
Postoperative radiotherapy of astrocytomas
Authors: Herfarth Klaus K. , Gutwein Sybille , Debus Jürgen 
Published: August 2002

AbstractAstrocytomas account for the majority of primary brain tumors. Low‐grade tumors are slowly growing tumors with relatively long overall survival. However, a high percentage of these tumors transform to more malignant, high‐grade tumors. High‐grade gliomas (anaplastic astrocytomas and glioblastoma multiforme) have a poor prognosis. Treatment options are capable of prolonging the natural history of the disease, but the long‐term survival is poor. This review discusses the different postoperative treatment options and the prognostic factors in low‐ and high‐grade astrocytomas. Semin. Surg. Oncol. 20:13–23, 2001. © 2001 Wiley‐Liss, Inc.
SCH 58261, an A2A adenosine receptor antagonist, counteracts parkinsonian‐like muscle rigidity in rats
Authors: Wardas Jadwiga , Konieczny Jolanta , Lorenc‐Koci Elżbieta 
Published: August 2002

AbstractThe aim of the present study was to find out whether blockade of adenosine A2A receptors by a selective antagonist, SCH 58261, influenced parkinsonian‐like muscle rigidity. Muscle tone was examined using a combined mechano‐ and electromyographic method which simultaneously measured muscle resistance (MMG) of a rat hindfoot to passive extension and flexion in the ankle joint and electromyographic activity (EMG) of the antagonistic muscles of that joint: gastrocnemius and tibialis anterior. Muscle rigidity produced by reserpine (5 mg/kg + α‐methyl‐p‐tyrosine, 250 mg/kg) was antagonized by SCH 58261 (0.1–5 mg/kg). SCH 58261 (5 mg/kg) also reduced reserpine‐enhanced tonic and reflex EMG activities in both the gastrocnemius and the tibialis muscles. Moreover, SCH 58261 in doses of 1 and 5 mg/kg abolished muscle resistance induced by haloperidol (0.5 mg/kg). However, only the highest dose of SCH 58261 (5 mg/kg) decreased tonic EMG activity enhanced by haloperidol. Administration of L‐DOPA (75 and 100 mg/kg) dose‐dependently decreased the muscle resistance as well as tonic EMG activity evoked by haloperidol. Combined administration of SCH 58261 (0.1 mg/kg) and L‐DOPA (50 mg/kg) in doses which did not affect the haloperidol‐induced muscle rigidity produced a pronounced synergistic effect. The ability of SCH 58261 to diminish the parkinsonian‐like muscle rigidity and to potentiate the effect of L‐DOPA in this model seems to indicate a therapeutic value of this compound in the treatment of Parkinson's disease. Synapse 41:160–171, 2001. © 2001 Wiley‐Liss, Inc.
Building blocks for a decision‐based integrated product development and system realization process
Authors: Prasad Biren (Brian) 
Published: August 2002

AbstractA key requirement, in a distributed product development environment at General Motors, was to provide a series of quantitative and qualitative mechanisms for integrating competing information from distributed agents. Such mechanisms must also account for provisions for combining different opinions, for resolving conflicts, and for finding a feasible or optimal solution at the end. We, at Electronic Data Systems (EDS), General Motors Account, developed a Decision‐based Integrated Product Development (DIPD) methodology to capture a system‐level optimization formulation as part of a product design, development and delivery (PD3) process. The paper describes this methodology in the context of system‐level optimization. DIPD employs the inputs, requirement, constraints, and output conventions to formulate the product realization problem in a distributed manner. The purpose of this DIPD methodology is to improve the performance characteristics of the product, process, and organization (PPO) relative to automobile consumer needs and expectations. DIPD builds the theory through a systematic revision and extension of the paradigms introduced earlier by optimization experts and practitioners including this author [Prasad,1996]. The eight parts of this DIPD methodology, called building blocks, are discussed at length in this paper. The first four blocks, 1–4, provide a conceptual framework for understanding the challenges and opportunities in DIPD. The last four parts, 5–8, of this methodology provide the building blocks for an analytical and conceptual framework for decision‐making, PPO improvements, and a large‐scale system optimization. © 2002 Wiley Periodicals, Inc. Syst Eng 5: 123–144, 2002
Aneuploidy induced in lymphocytes of parents of trisomic 21 children
Authors: Caria Helena , Chaveca Teresa , Rueff José 
Published: August 2002

AbstractA possible predisposition to aneuploidy in trisomic 21 individuals, their parents, and a control group was evaluated. Peripheral blood lymphocytes from those three groups were used to study the induction of micronuclei (MN) by mitomycin C, cyclophosphamide, and quercetin. Induced MN were further analysed by C‐banding and CREST antibody. Trisomic 21 individuals have spontaneous frequencies of MN significantly higher than their parents and the control group. Quercetin without metabolic activation induces MN in trisomic 21 and their parents at a significantly higher level than in control group. The group of the parents of trisomic 21 individuals exhibits higher frequencies of induced MN by mitomycin C and cyclophosphamide than controls. Mitomycin C significantly induced CREST‐positive‐MN in ten of the sixteen parents evaluated. The results obtained seem to suggest a unique behaviour for the parents of trisomic 21 patients consisting in an increased susceptibility to chromosome loss in the presence of clastogenic genotoxicants, suggesting a higher predisposition to aneuploidy. Teratogenesis Carcinog. Mutagen. 21:369–382, 2001. © 2001 Wiley‐Liss, Inc.
Polychlorinated biphenyls promote 1‐nitropyrene‐induced lung tumorigenesis without the induction of K‐ras gene mutation in A/J mice
Authors: Nakanishi Yoichi , Bai Feng , Inoue Koji , Takayama Koichi , Pei Xin‐Hai , Harada Taishi , Izumi Miiru , Kimotsuki Kanehito , Tokiwa Hiroshi , Hara Nobuyuki 
Published: August 2002

AbstractAlthough the effects of polychlorinated biphenyls (PCBs) on human lung carcinogenesis are suggested from the massive PCBs poisoning that occurred in Japan designated “Yusho,” the detailed molecular mechanism are unknown. 1 nitropyrene (1‐NP), an ubiquitous and abundant environmental pollutant, is known to be detected in lung tissues derived from patients with lung cancer in Japan, and its relation to lung carcinogenesis is also suggested. We investigated the effects of PCBs (Kanechlor‐400) on 1‐NP‐induced lung tumorigenesis in A/J mice. PCBs were administered intraperitoneally followed by ip injection of 1‐NP. The lung lesions were examined 18 weeks after the final treatment. In the control group, no neoplastic lesions were induced in the lung. In the PCB group, preneoplastic lesions such as hyperplasia and adenoma were induced in 2/10 (20%) mice. In 1‐NP group and in PCB + 1‐NP group, lung lesions including adenocarcinoma were induced in 16/20 (80%) and 13/13 (100%) mice, respectively. Both the number and the size of tumors in PCB + 1‐NP group were significantly greater than those in 1‐NP group. K‐ras gene mutation, CAA to CGA in codon 61 or GGT to GAT in codon 12, was found in either 1‐NP group or PCB + 1‐NP group but not in the PCB group. There was no difference in the pattern of K‐ras mutation associated with the pretreatment with PCBs. These results suggest that PCBs promote 1‐NP‐induced lung tumorigenesis and may support, at least in part, the mechanism of the high incidence of lung cancer in patients with Yusho. Teratogenesis Carcinog. Mutagen. 21:395–403, 2001. © 2001 Wiley‐Liss, Inc.
Chemistry and chemical biology of taxane anticancer agents
Authors: Miller Michael L. , Ojima Iwao 
Published: August 2002

AbstractTaxol® (paclitaxel) and Taxotère® (docetaxel) are currently considered to be among the most important anticancer drugs in cancer chemotherapy. The anticancer activity of these drugs is ascribed to their unique mechanism of action, i.e., causing mitotic arrest in cancer cells, leading to apoptosis through inhibition of the depolymerization of microtubules. Although both paclitaxel and docetaxel possess potent antitumor activity, treatment with these drugs often results in a number of undesirable side effects, as well as multidrug resistance (MDR). Therefore, it has become essential to develop new anticancer agents with superior pharmacological properties, improved activity against various classes of tumors, and fewer side effects. This paper describes an account of our research on the chemistry of paclitaxel and taxoid anticancer agents at the biomedical interface, including:

The structure‐activity relationship (SAR) study of taxoids leading to the development of the “second‐generation” taxoids, which possess exceptional activity against drug‐resistant cancer cells expressing the MDR phenotype.
Development of fluorinated taxoids to study the bioactive conformation of paclitaxel and photoaffinity labeling taxoids for mapping of the drug‐binding domain on both microtubules and P‐glycoprotein.
The synthesis of novel macrocyclic taxoids for the investigation into the common pharmacophore for microtubule stabilizing anticancer agents.

© 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:195–211, 2001
Learning science through technological design
Authors: Roth Wolff‐Michael 
Published: August 2002

AbstractIn the course of a decade of research on learning in technology‐centered classrooms, my research group has gained considerable understanding of why and how students learn science by designing technology. In this article I briefly review two dimensions in which science and technology share fundamental similarities: (a) the production and transformation of representations and (b∥ the action‐oriented language describing the two domains. Because it is fundamentally problematic to derive whatoughtto happen in science classrooms from other dimensions, I provide three episodes to illustrate what and how students know and learn science during technological design activities. Episodes and analyses embody the two dimensions previously outlined. Because these episodes are representative of the database established during an extensive research program, I suggest there is sufficient ground for using and investigating science‐through‐technology curricula. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 768–790, 2001
Urban school leadership for elementary science instruction: Identifying and activating resources in an undervalued school subject
Authors: Spillane James P. , Diamond John B. , Walker Lisa J. , Halverson Rich , Jita Loyiso 
Published: August 2002

AbstractThis article explores school leadership for elementary school science teaching in an urban setting. We examine how school leaders bring resources together to enhance science instruction when there appear to be relatively few resources available for it. From our study of 13 Chicago elementary (K–8) schools' efforts to lead instructional change in mathematics, language arts, and science education, we show how resources for leading instruction are unequally distributed across subject areas. We also explore how over time leaders in one school successfullyidentifiedandactivatedresources for leading change in science education. The result has been a steady, although not always certain, development of science as an instructional area in the school. We argue that leading change in science education involves the identification and activation of material resources, the development of teachers' and school leaders' human capital, and the development and use of social capital. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 918–940, 2001
Teratogen update: Lyme disease
Authors: Elliott Daniel J. , Eppes Stephen C. , Klein Joel D. 
Published: August 2002

AbstractWe reviewed the world literature concerning the reproductive effects of Lyme disease (LD).Borrelia burgdorferi, which is the etiology of LD, is a spirochete and, as such, may share the potential for causing fetal infection, which may occur in the setting of maternal spirochetemia. Information concerning the effects of gestational LD derives from case reports and series, epidemiologic studies, and experimental animal models. Although provocative, these studies fail to define a characteristic teratogenic effect. However, skin and cardiac involvement have predominated in some reports. Pregnancy wastage has been suggested primarily by animal studies. Gestational LD appears to be associated with a low risk of adverse pregnancy outcome, particularly with appropriated antibiotic therapy. Suggestions for management of clinical situations are presented. Teratology 64:276–281, 2001. © 2001 Wiley‐Liss, Inc.
A match moving technique for merging CG cloth and human movie sequences
Authors: Hoshino Jun'ichi , Yamamoto Masanobu , Saito Hirofumi 
Published: August 2002

AbstractMerging computer‐generated objects onto a human video sequence is an important technique for many applications such as augmented reality and special effects in movies. In this paper, we propose a new method for merging virtual objects onto the human video sequence. First, we track the current 3D pose of the human body by using spatio‐temporal analysis. Then we generate CG objects and merge them with the human body in video. In this paper, we demonstrate examples of merging virtual cloth with the video‐captured images. Copyright © 2001 John Wiley & Sons, Ltd.
A 3D parametric tongue model for animated speech
Authors: King Scott A. , Parent Richard E. 
Published: August 2002

AbstractWe present a tongue model for use in computer‐animated speech. The model is capable of representing tongue shapes during the production of English vowels and consonants as well as general motion of the tongue. Geometrically, the model is composed of a B‐spline surface with 60 control points and an 8×13 grid of bi‐cubic patches. We also present a parameterization of the model that requires only six parameters for use during speech production. This parameterization can also be used to define the deformation of other tongue models. Copyright © 2001 John Wiley & Sons, Ltd.
A grasp‐based motion planning algorithm for character animation
Authors: Kalisiak Maciej , van de Panne Michiel 
Published: August 2002

AbstractThe design of autonomous characters capable of planning their own motions continues to be a challenge for computer animation. We present a novel kinematic motion‐planning algorithm for character animation which addresses some of the outstanding problems. The problem domain for our algorithm is as follows: given a constrained environment with designated handholds and footholds, plan a motion through this space towards some desired goal. Our algorithm is based on a stochastic search procedure which is guided by a combination of geometric constraints, posture heuristics, and distance‐to‐goal metrics. The method provides a single framework for the use of multiple modes of locomotion in planning motions through these constrained, unstructured environments. We illustrate our results with demonstrations of a human character using walking, swinging, climbing, and crawling in order to navigate through various obstacle courses. Copyright © 2001 John Wiley & Sons, Ltd.