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Various Methodologies (various + methodology)

Distribution by Scientific Domains
Life Sciences33%

Selected Abstracts

Cover Picture: Electrophoresis 16'2010

ELECTROPHORESIS, Issue 16 2010
Article first published online: 19 AUG 2010
Issue no. 16 is a regular issue with an Emphasis on "Proteins and Proteomics" comprising 20 manuscripts distributed over 4 separate parts. Part I has 7 research articles on various aspects of proteins and proteomics including combinatorial peptide ligand library for accessing low abundance proteins, analysis of membrane proteins, proteomic profiling of human colon cancer cells, quantitative determinations of biomarkers in clinical diagnostics, recombinant factor VIII, analysis of E. coli soluble proteins, and a weakly basic amino-reactive fluorescent label for IEF of proteins and chip electrophoresis. Part II has 2 research articles dealing with the CE analysis of magnetic nanoparticles and a microfluidic magnetic bead impact for cell stimulation. Part III consists of 2 research articles dealing with on-line preconcentration in CE. Instrumentation, devices and various methodologies are described in 9 research articles, which make the content of Part IV. Featured articles include: Combinatorial peptide ligand library plasma treatment: Advantages for accessing low-abundance proteins ((doi: 10.1002/elps.201000188)) Precautions to improve the accuracy of quantitative determinations of biomarkers in clinical diagnostics ((doi: 10.1002/elps.201000243)) Rapid identification of Candida albicans in blood by combined capillary electrophoresis and fluorescence in situ hybridization ((doi: 10.1002/elps.201000138)) [source]

Cover Picture: Electrophoresis 8'2010

ELECTROPHORESIS, Issue 8 2010
Article first published online: 20 APR 2010
Issue no. 8 is a regular issue comprising19 manuscripts distributed over four distinct parts. Part I is on proteins and proteomics and has 5 articles; Part II is on nucleic acids with 5 articles on DNA purification, sequencing, genotyping and differential gene expression; Part III has 4 articles on droplet dispensing and particle separation; Part IV is on various methodologies and applications assembling 5 articles on improved sample preparation method for glycan analysis by CE, measurement of intracellular accumulation chemotherapeutic drugs in cancerous cells, metabolic monitoring in microfluidic cell arrays, microchip electrophoresis for continuous monitoring of microdialysis samples, and determination of glyphosate and its metabolites in plant materials by CE. Featured articles include: Delta2D and Proteomweaver: Performance evaluation of two different approaches for two-dimensional electrophoresis analysis. ((10.1002/elps.200900766)) A Multidimensional Electrophoretic System of Separation for the Analysis of Gene Expression (MESSAGE). ((10.1002/elps.200900624)) Particle trapping using dielectrophoretically patterned carbon nanotubes. ((10.1002/elps.200900717)) [source]

Analysis and comparison of morphological reconstructions of hippocampal field CA1 pyramidal cells

HIPPOCAMPUS, Issue 3 2005
José Ambros-Ingerson
Abstract Morphological reconstructions have become a routine and valuable tool for neuroscientists. The accuracy of reconstructions is a matter of considerable interest given that they are widely used in computational studies of neural function. Despite their wide usage, comparisons of reconstructions obtained using various methodologies are lacking. We reviewed reconstructions of hippocampal CA1 pyramidal cells from five published studies and found marked differences in some of the most basic measurements. For four of the five studies means of total cell length clustered in the 11,479,13,417-,m range. The remaining study had a significantly larger value for this index at 16,992 ± 5,788 ,m. Surface area means varied more than 4-fold from 16,074 to 67,102 ,m2. Volume means varied more than 8-fold from 3,828 to 30,384 ,m3. Simulated passive input resistance means varied from 38.0 to 172.1 M,, reflecting the variability in cell dimensions. Estimates of the electrotonic length varied from 1.26 to 1.56. In two reconstructions used in previously published studies, simulated somatic excitatory postsynaptic potentials (EPSPs) varied 2,4-fold in amplitude, time to peak and half-width, for synaptic inputs at similar locations. Substantial jitter on the z -axis was identified as one likely source of the discrepancy in total cell length, while substantial differences in diameter measurements across studies, and sometimes within the same study, accounted for the variability in surface area and volume. While some part of the observed variability is surely due to the diversity of CA1 pyramidal cells, our analysis suggests that a substantial portion stemmed from methodological inconsistencies and from technological limitations. Suggestions are made for improving the quality and usefulness of morphological reconstructions. We conclude that reconstructions across studies have substantial variability in measures that are very relevant to neuronal function. Consequently, modelers are advised to use more than just one reconstructed cell in their simulations of neural function. © 2004 Wiley-Liss, Inc. [source]

Controlled Growth Factor Delivery for Tissue Engineering

ADVANCED MATERIALS, Issue 32-33 2009
Prakriti Tayalia
Abstract Growth factors play a crucial role in information transfer between cells and their microenvironment in tissue engineering and regeneration. They initiate their action by binding to specific receptors on the surface of target cells and the chemical identity, concentration, duration, and context of these growth factors contain information that dictates cell fate. Hence, the importance of exogenous delivery of these molecules in tissue engineering is unsurprising, considering their importance for tissue regeneration. However, the short half-lives of growth factors, their relatively large size, slow tissue penetration, and their potential toxicity at high systemic levels, suggest that conventional routes of administration are unlikely to be effective. In this review, we provide an overview of the design criteria for growth factor delivery vehicles with respect to the growth factor itself and the microenvironment for delivery. We discuss various methodologies that could be adopted to achieve this localized delivery, and strategies using polymers as delivery vehicles in particular. [source]

Output feedback stabilizability and passivity in nonstationary and nonlinear systems,

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 7 2010
Itzhak Barkana
Abstract Passivity properties and passivity conditions have been shown to be very important for the stability of various methodologies of control with uncertainty in linear-time-invariant (LTI) systems. Many publications have defined the conditions that allow LTI systems to become strictly passive (and their transfer function strictly positive real) via constant or dynamic output feedback. As beyond the usual uncertainty, real-world systems are not necessarily invariant, this paper expands the applicability of previous results to nonstationary and nonlinear systems. The paper first reviews a few pole,zero dynamics definitions in nonstationary systems and relates them to stability and passivity of the systems. The paper then finds the sufficient conditions that allow nonstationary systems to become stable and strictly passive via static or dynamic output feedback. Applications in robotics and adaptive control are also presented. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Detecting local convexity on the pareto surface

JOURNAL OF MULTI CRITERIA DECISION ANALYSIS, Issue 1 2002
Georges Fadel
Abstract Recent regain in interest in multi-criteria optimization approaches to provide a designer with multiple solutions to select from and support decisions has led to various methodologies to generate such solutions and possibly approximate the Pareto set. This paper introduces the notions of H - and w -convexities, and develops a simple method to identify local convexity of Pareto hyper-surfaces since their shape can dictate the choice of the method to use to obtain Pareto solutions and possibly to build an approximation of that set. The method is based on comparing the results from the weighting method to those of the Tchebycheff method at any point on the Pareto hyper-surface. If, under some conditions, the points obtained from the two methods are identical or not, a local convexity or its lack can be assumed at that location and in its immediate neighbourhood. A numerical example is included. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Quantitative identification of protein nitration sites

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 6 2009
Giovanni Chiappetta
Abstract Several labelling strategies have been developed targeting specific amino acid residues and/or PTMs. Methods specifically tailored for the qualitative and sometimes quantitative determination of PTMs have emerged. Many research groups have focused their attention towards o-nitrotyrosine residues, developing various methodologies for their identification, while direct quantification has remained elusive. So far the iTRAQ chemistry has been limited to primary amines. Here, we report a new strategy based on the use of iTRAQ reagents coupled to MS analysis for the selective labelling of o-nitrotyrosine residues. This method was proved to lead to the simultaneous localisation and quantification of nitration sites both in model proteins and in biological systems. [source]

Methods for HPV detection in exfoliated cell and tissue specimens

APMIS, Issue 6-7 2010
PETER J.F. SNIJDERS
Snijders PJF, Heideman DAM, Meijer CJLM. Methods for HPV detection in exfoliated cell and tissue specimens. APMIS 2010; 118: 520,528. Given the causal involvement of high-risk human papillomaviruses (HPVs) in cervical cancer and a subset of squamous cell carcinomas of other anogenital regions as well as the oropharynx, much attention has been focused on the development and application of HPV detection assays. HPV detection assays are almost exclusively based on the detection of viral nucleic acids, mostly viral DNA. The HPV detection methods that are nowadays in use can broadly be subdivided into target amplification methods and signal amplification methods. In this review, several principles of various methodologies are explained and examples of some commonly used HPV detection assays are given. In addition, attention is paid to the use of HPV assays for detecting clinically meaningful HPV infections, i.e. infections related to (pre)cancerous lesions, e.g. cervical cancer screening purposes. For the latter, it is important that HPV tests are clinically validated according to validation strategies as outlined in guidelines. [source]

Quality management and quality practice: Perspectives on their history and their future

APPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 1 2009
N. I. Fisher
Abstract The purpose of this article and a companion article is to explore a number of topics in Statistics in Business and Industry. This article sketches the history of Quality Management, from its emergence in the late 19th and early 20th centuries through to the present day. Particular emphasis is placed on activities in Japan immediately following the end of the Second World War, and subsequent developments elsewhere in the world. We draw a careful distinction between Quality Management and various methodologies that aid in its implementation, such as Six Sigma. In the words of one management practitioner, Norbert Vogel, ,TQM in its broadest sense examines all aspects of management and the alternative methodologies being promoted are merely sub-sets of what should be an integrated management system.' The article concludes with some speculative thoughts about the future of Quality Management from a statistician's point of view. Copyright © 2009 John Wiley & Sons, Ltd. [source]