An overview of group sequential methods in longitudinal clinical trials

During the last decade, several papers have been published on group sequential methods in general and on sequential longitudinal clinical trials in particular. This paper gives an overview of the proposed methods, emphasizing longitudinal clinical trials. Furthermore, it tries to answer some practical questions that may arise during the conduct of interim analyses in longitudinal trials. Simulations have been carried out to obtain insight in these practical considerations.     

An overview on fabrication methods for polymer optical fibers

An overview of the most important materials and fabrication methods for polymer optical fibers is given. In addition to conventional fabrication methods a newly developed continuous melt spinning process for graded‐index fibers is presented that uses rapid cooling in a water quench for the profile formation. The approaches presented are divided into continuous and discontinuous processes for step‐ and graded‐index profile fibers as well as microstructured polymer optical fibers. The methods are described in detail and discussed concerning their efficiency, quality of produced fibers and scalability. © 2014 Society of Chemical Industry     

An overview on methods for the production of carbon nanotubes

Carbon nanotubes (CNTs) are one of the most exciting discoveries in nanoscale sciences. A brief survey of experimental work directed towards the synthesis of CNTs has been discussed. The various methods of production of CNTs are explained outlining their capabilities, efficiencies and possible exploitation as economic large scale production. Among the discussed techniques, the chemical vapor deposition (CVD) appears to be the most potential way to produce high quality of CNTs at high yield. The advantages of CVD over other techniques are also explained and the effects of process parameter on the synthesis of these nanomaterials are discussed.     

Joining methods for plastics and plastic composites: An overview

Joining of plastics and plastic composites is becoming important because of the emerging structural applications of these materials. While providing an overview of all joining methods, this paper emphasizes the welding of thermoplastic materials. Different welding techniques, together with their main advantages and disadvantages, are briefly described. A selective bibliography, in which the 259 references have been arranged chronologically for each technology type, provides a guide to the literature.     

Synthesis of copper nanoparticles : An overview of the various methods

The synthesis of metal nanoparticles has received much attention due to their wide range of applications. Copper nanoparticles have attracted much attention due to their unique optical and electrical properties. Copper is relatively cheap in comparison to precious metals like gold and silver and also has high antibacterial properties. This review gives a brief overview of the available research works considering the synthesis of copper nanoparticles by chemical, physical, and biological methods.     

Current methods for the identification and quantitation of ceramides: An overview

Ceramides are key compounds in the metabolism of sphingolipids and are emerging as important second messengers for various cellular processes including cell cycle arrest, differentiation, senescence, apoptosis, and others. Because of their important biological functions, exact analysis of their molecular species and concentrations is crucial for elucidating their function and metabolism. Toward this goal, several methods have been developed for the identification and quantitation of cellular ceramide levels. Methods have been developed utilizing thin-layer or high-performance liquid chromatography. Mass spectrometry also has become increasingly utilized. The Escherichia coli diacylglycerol kinase assay is one of the most frequently used techniques for ceramide quantitation. This review presents a current summary of methods used for the identification and quantitation of ceramides.     

An overview of methods for interval-censored data with an emphasis on applications in dentistry

Interval-censored time-to-event data occur in many medical areas, with dentistry or AIDS research being typical representatives. This article reviews methods for the analysis of such data, with an emphasis on the use of the accelerated failure time (AFT) model. A flexible AFT model (avoiding parametric assumptions on the distribution of the error term) is described in greater detail and is used to solve a typical dental question in a longitudinal oral health study.     

Enterprise-wide modeling & optimization—An overview of emerging research challenges and opportunities

The process systems engineering (PSE) as well as the operations research and management science (ORMS) literature has hitherto focused on disparate processes and functions within the enterprise. These themes have included upstream R&D pipeline management, planning and scheduling in batch and continuous manufacturing systems and more recently supply chain optimization under uncertainty. In reality, the modern process enterprise functions as a cohesive entity involving several degrees of cross-functional co-ordination across enterprise planning and process functions. The complex organizational structures underlying horizontally and vertically integrated process enterprises challenge our understanding of cross-functional co-ordination and its business impact. This article looks at the impact of enterprise-wide cross-functional coordination on enterprise performance, sustainability and growth prospects. Cross-functional coordination is defined as the integration of strategic and tactical decision-making processes involving the control of financial and inventory flows (both internal and external) as well as resource deployments. Initially, we demonstrate the existence of cross-functional decision-making dependencies using an enterprise network model. Subsequently, we discuss interactions between enterprise planning decisions involving project financing, debt-equity balancing, R&D portfolio selection, risk hedging with real derivative instruments, supply chain asset creation and marketing contracts which influence decision-making at the activity/process level. Several case studies are included to re-enforce the point that planning and process decisions need to be integrated.     

SHS in Italy: An overview

In this work, the evolution of SHS research and development taking place in Italy during the last twenty years are addressed. The activity performed by the Italian research groups involved in this field that belong to the Universities of Cagliari, Genoa, Pavia, and Sassari, Polytechnic of Turin, and National Research Council IENI-Milan, respectively, are presented. The major results obtained from both the modeling and experimental points of view are reviewed while highlighting the international collaborations of each research group. Presented at the International Conference on Historical Aspects of SHS in Different Countries, October 22–27, 2007, Chernogolovka, Moscow, Russia.     

An overview of caprolactam synthesis

Caprolactam is the precursor of many industrial chemical productions as in nylon industry, plastic industry, paint industry, lysine synthesis and cross-linking for polyurethanes. The production of caprolactam has been focus much from last three decades among the scientific community to fulfill the industrial need under environment precautions. Herein a sequential and explanatory review broadly covering the transformation of a different substrate as cyclohexanone oxime, cyclohexanone, cyclohexanol, cyclohexane, and biorenewable sources into caprolactam is presented. For every substrate, a wide range of catalyst including homogeneous as well as the heterogeneous system has been deeply considered. This study will be helpful for developing alternative industrial route for production of caprolactam.     

An overview of subspace identification

This paper provides an overview of the state of the art of subspace identification methods for both open-loop and closed-loop systems. Practical considerations and future directions are given at the end of the paper.     

Two-mode clustering methods: a structured overview

In this paper we present a structured overview of methods for two-mode clustering, that is, methods that provide a simultaneous clustering of the rows and columns of a rectangular data matrix. Key structuring principles include the nature of row, column and data clusters and the type of model structure or associated loss function. We illustrate with analyses of symptom data on archetypal psychiatric patients.     

Introduction and overview. Statistical methods in genetic epidemiology

Common terms used in genetics with multiple meanings are explained and a brief overview given of the four major areas of genetic epidemiology--the study of familial aggregation, segregation, cosegregation and association. Familial aggregation measures the potential for a trait to have a genetic aetiology. Segregation analysis uncovers single gene segregation. Cosegregation with genetic markers gives rise to linkage, which is used to locate trait genes on the genome. Association analysis is used for fine mapping, but rests on the assumption that linkage disequilibrium exists.     

材料研究中工艺参数的优化方法

介绍了目前材料研究中常用的几种工艺参数的优化方法,包括主成分分析法、人工神经网络法、遗传算法和偏最小二乘法。对其原理和特点做了比较,并列举了应用实例。     

SHS extrusion: An overview

Overviewed is the state-of-art in the science and technology for extrusion of still hot SHS products (also termed SHS extrusion). Addressed are the experimental and theoretical studies on rheological behavior of materials with a limited duration of their ductility. The structures/properties of extruded materials and items are also presented and discussed. Presented are the examples of practical implementation of the process to production of rod-like electrodes for electrospark alloying from new multifunctional materials, such as nanograined cermets, MAX compounds, and intermetallics.     

Green composites: An overview

The use of natural fibers to reinforce polymers is a well‐established practice, and biocomposites are increasingly used in sectors such as automotive and construction. Green composites are a specific class of biocomposites, where a bio‐based polymer matrix is reinforced by natural fibers, and they represent an emerging area in polymer science. This work discusses the environmental benefits deriving from the use of natural fibers in polymer composites and from substitution of oil‐derived polymers by bio‐based polymers as matrix material. New trends in the selection of natural fibers, that is, from waste rather than from valuable crops are described. Recently developed thermoplastic and thermosetting bio‐based polymers are reviewed, and commercially available green composites obtained thereof are discussed. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

An overview on oxyfuel coal combustion—State of the art research and technology development

Oxyfuel combustion is seen as one of the major options for CO₂ capture for future clean coal technologies. The paper provides an overview on research activities and technology development through a fundamental research underpinning the Australia/Japan Oxyfuel Feasibility Project. Studies on oxyfuel combustion on a pilot-scale furnace and a laboratory scale drop tube furnace are presented and compared with computational fluid dynamics (CFD) predictions. The research has made several contributions to current knowledge, including; comprehensive assessment on oxyfuel combustion in a pilot-scale oxyfuel furnace, modifying the design criterion for an oxy retrofit by matching heat transfer, a new 4-grey gas model which accurately predicts emissivity of the gases in oxy-fired furnaces has been developed for furnace modelling, the first measurements of coal reactivity comparisons in air and oxyfuel at laboratory and pilot-scale; and predictions of observed delays in flame ignition in oxy-firing.     

An overview of gold-catalysed oxidation processes

Gold and gold/platinum group metals (Au/PGM) catalysts are active under mild conditions or even at ambient temperature or less and this makes them unique. They will therefore be effective in reducing running costs of chemical plants and increasing the selectivity of the reactions involved where applicable. In pollution control applications such as air cleaning, low light-off autocatalysts, and purification of hydrogen streams used for fuel cells they have the characteristics to become the catalysts of choice, especially now that their durability and resistance to poisons is being shown to be better than was anticipated. The mechanisms of these gold catalysed reactions are still uncertain but both oxidised and metallic gold are probably involved, and the details depend on types of reaction and the conditions used.