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Leading Method (leading + method)
Selected AbstractsCapillary electrophoresis versus differential scanning calorimetry for the analysis of free enzyme versus enzyme-ligand complexes: In the search of the ligand-free status of cholinesterasesELECTROPHORESIS, Issue 2 2006Daniel Rochu Dr. Abstract Cholinesterases (ChEs) are highly efficient biocatalysts whose active site is buried in a deep, narrow gorge. The talent of CE to discover inhibitors in the gorge of highly purified preparations has fairly altered the meaning of a ChE ligand-free status. To attempt at a description of this one, we investigated the stability of Bungarus fasciatus acetylcholinesterase (AChE), alone or complexed with different inhibitors. Determination of midtransition temperature for thermal denaturation, using differential scanning calorimetry (DSC) and CE, provided conflicting results. Discrepancies strongly question the reality of a ligand-free AChE state. DSC allowed estimation of the stability of AChE-ligands complexes, and to rank the stabilizing effect of different inhibitors. CE acted as a detector of hidden ligands, provided that they were charged, reversibly bound, and thus dissociable upon action of electric fields. Then, CE allowed quantification of the stability of ligand-free AChE. CE and DSC providing each fractional and nonredundant information, cautious attention must be paid for actual estimation of the conformational stability of ChEs. Because inhibitors used in purification of ChEs by affinity chromatography are charged, CE remains a leading method to estimate enzyme stability and detect the presence of bound hidden ligands. [source] Revised capillary suction time (CST) test to reduce consumable costs and improve dewaterability interpretationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2006Miklas Scholz Abstract The aim of this paper is to critically assess the standard capillary suction time (CST) test and to propose a modified device (prototype) and a revised CST procedure. The empirical CST test (using a circular funnel) is well established as the leading method for the determination of sludge dewaterability in spite of its current shortcomings such as restricted modelling possibilities, and therefore the ability to predict physical processes such as the amount of water bound by the paper. Nevertheless, the CST apparatus is portable, and the method is easy to conduct, quick, cost-effective and accurate, if the product of solid concentration and average specific resistance to filtration is of interest. A novel prototype with a rectangular instead of a circular funnel incorporating a stirrer (optional), and using a cheaper paper with similar or improved characteristics is proposed to reduce consumable costs and improve dewaterability interpretation. Copyright © 2005 Society of Chemical Industry [source] New attempts to quantify concentric needle electromyographyMUSCLE AND NERVE, Issue S11 2002Masahiro Sonoo MD, PhDArticle first published online: 4 JUN 200 Abstract Quantitative motor unit potential (MUP) analysis, which is a leading method of quantitative evaluation of concentric needle electromyography, has several inherent limitations. First, the most essential features of neurogenic or myogenic changes manifest as recruitment abnormalities, rather than as changes in MUP morphology. Second, two factors related to MUP sampling, focusing and level of contraction, greatly influence the parameters of sampled MUPs. Third, the MUP duration, considered to be the cardinal parameter in MUP analysis, has several drawbacks, including low stability and low discriminant sensitivity. We developed a new MUP parameter, the size index (SI), which is calculated from the MUP amplitude and area/amplitude ratio (thickness). The SI remained almost constant during electrode movements, as demonstrated by manual scanning of MUPs. It is a stable and robust parameter and achieved an extremely high ability to discriminate between normal and large neurogenic MUPs. It identifies features related to the sound produced by the MUP on the audio monitor, which is often used by trained electromyographers for qualitative assessments of MUPs. © 2002 Wiley Periodicals, Inc. Muscle Nerve Supplement 11: S98,S102, 2002 [source] Extending phylogenetic studies of coevolution: secondary Brooks parsimony analysis, parasites, and the Great ApesCLADISTICS, Issue 2 2003Daniel R Brooks Dowling recently compared the empirical properties of Brooks parsimony analysis (BPA) and the leading method for studying phylogenetic aspects of coevolution, reconciled tree analysis (using the computer program TreeMap), based on a series of simulations. Like the majority of authors who have compared BPA with other methods, however, Dowling considered only the form of BPA proposed in 1981 and did not take into account various modifications of the method proposed from 1986 to 2002. This leaves some doubt as to the robustness of his assessments of both the superiority of BPA and its shortcomings. We provide a précis of the principles of contemporary BPA, including ways to implement it algorithmically, using either Wagner algorithm-based or Hennigian argumentation-based approaches, followed by an empirical example. Our study supports Dowling's fundamental conclusions about the superiority of primary BPA relative to TreeMap. However, his conclusions about the shortcomings of BPA due to inclusive ORing (i.e., the production of ghost taxa) are incorrect, as secondary BPA eliminates inclusive ORing from the method. Secondary BPA provides a more complete account of the evolutionary associations between the parasite groups and their hosts than does primary BPA, without sacrificing any indirectly generated information about host phylogeny. Secondary BPA of two groups of nematodes inhabiting Great Apes shows that TreeMap analysis underestimated the amount of cospeciation in the evolution of the nematode genus Enterobius. [source] | ||||||||||