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Traditional Analysis (traditional + analysis)
Selected AbstractsA Novel Methodological Approach for the Analysis of Host,Ligand Interactions,CHEMPHYSCHEM, Issue 2 2007Daniela Strat Dr. Abstract Traditional analysis of drug-binding data relies upon the Scatchard formalism. These methods rely upon the fitting of a linear equation providing intercept and gradient data that relate to physical properties, such as the binding constant, cooperativity coefficients and number of binding sites. However, the existence of different binding modes with different binding constants makes the implementation of these models difficult. This article describes a novel approach to the binding model of host,ligand interactions by using a derived analytical function describing the observed signal. The benefit of this method is that physically significant parameters, that is, binding constants and number of binding sites, are automatically derived by the use of a minimisation routine. This methodology was utilised to analyse the interactions between a novel antitumour agent and DNA. An optical spectroscopy study confirms that the pentacyclic acridine derivative (DH208) binds to nucleic acids. Two binding modes can be identified: a stronger one that involves intercalation and a weaker one that involves oriented outer-sphere binding. In both cases the plane of the bound acridine ring is parallel to the nucleic acid bases, orthogonal to the phosphate backbone. Ultraviolet (UV) and circular dichroism (CD) data were fitted using the proposed model. The binding constants and the number of binding sites derived from the model remained consistent across the different techniques used. The different wavelengths at which the measurements were made maintained the coherence of the results. [source] Shear band evolution and accumulated microstructural development in Cosserat mediaINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 10 2004A. Tordesillas Abstract This paper prepares the ground for the continuum analysis of shear band evolution using a Cosserat/micropolar constitutive equation derived from micromechanical considerations. The nature of the constitutive response offers two key advantages over other existing models. Firstly, its non-local character obviates the mathematical difficulties of traditional analyses, and facilitates an investigation of the shear band evolution (i.e. the regime beyond the onset of localization). Secondly, the constitutive model parameters are physical properties of particles and their interactions (e.g. particle stiffness coefficients, coefficients of inter-particle rolling friction and sliding friction), as opposed to poorly understood fitting parameters. In this regard, the model is based on the same material properties used as model inputs to a discrete element (DEM) analysis, therefore, the micromechanics approach provides the vehicle for incorporating results not only from physical experiments but also from DEM simulations. Although the capabilities of such constitutive models are still limited, much can be discerned from their general rate form. In this paper, an attempt is made to distinguish between those aspects of the continuum theory of localization that are independent of the constitutive model, and those that require significant advances in the understanding of micromechanics. Copyright © 2004 John Wiley & Sons, Ltd. [source] A probability-based analysis of temporal and spatial co-occurrence in grassland birdsJOURNAL OF BIOGEOGRAPHY, Issue 12 2006Joseph A. Veech Abstract Aim, To test for non-random co-occurrence in 36 species of grassland birds using a new metric and the C -score. The analysis used presence,absence data of birds distributed among 305 sites (or landscapes) over a period of 35 years. This analysis departs from traditional analyses of species co-occurrence in its use of temporal data and of individual species' probabilities of occurrence to derive analytically the expected co-occurrence between paired species. Location, Great Plains region, USA. Methods, Presence,absence data for the bird species were obtained from the North American Breeding Bird Survey. The analysis was restricted to species pairs whose geographic ranges overlapped. Each of 541 species pairs was classified as a positive, negative, or non-significant association depending on the mean difference between the observed and expected frequencies of co-occurrence over the 35-year time-span. Results, Of the 541 species pairs that were examined, 202 to 293 (37,54%) were positively associated, depending on which of two null models was used. However, only a few species pairs (<5%) were negatively associated. An additional 89 species pairs did not have overlapping ranges and hence represented de facto negative associations. The results from analyses based on C -scores generally agreed with the analyses based on the difference between observed and expected co-occurrence, although the latter analyses were slightly more powerful. Main conclusions, Grassland birds within the Great Plains region are primarily distributed among landscapes either independently or in conjunction with one another. Only a few species pairs exhibited repulsed or segregated distributions. This indicates that the shared preference for grassland habitat may be more important in producing coexistence than are negative species interactions in preventing it. The large number of non-significant associations may represent random associations and thereby indicate that the presence/absence of other grassland bird species may have little effect on whether a given focal species is also found within the landscape. In a broader context, the probability-based approach used in this study may be useful in future studies of species co-occurrence. [source] Patterns in nursing home medication errors: disproportionality analysis as a novel method to identify quality improvement opportunitiesPHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 10 2010Richard A. Hansen Abstract Purpose To explore the use of disproportionality analysis of medication error data as a novel method to identify relationships that might not be obvious through traditional analyses. This approach can supplement descriptive data and target quality improvement efforts. Methods Data came from the Medication Error Quality Initiative (MEQI) individual event reporting system. Participants were North Carolina nursing homes who submitted incident reports to the Web-based MEQI data repository during the 2006 and 2007 reporting years. Data from 206 nursing homes were summarized descriptively and then disproportionality analysis was applied. Associations between medication type and possible causes at the state level were explored. A single nursing home was selected to illustrate how the method might inform quality improvement at the facility level. Disproportionality analysis of drug errors in this home was compared with benchmarking. Results Statewide, 59 drug-cause pairs met the disproportionality signal and 11 occurred in 10 or more reports. Among these, warfarin was co-reported with communication errors; esomeprazole, risperidone, and nitrofurantoin were disproportionately associated with transcription error; and oxycodone and morphine were disproportionately reported with name confusion. Facility-level analyses illustrate how descriptive frequencies and disproportionality analysis are complementary, but also identify different safety targets. Conclusions Exploratory analysis tools can help identify medication error types that occur at disproportionate rates. Candidate associations might be used to target patient safety work, although further evaluation is needed to determine the value of this information. Copyright © 2010 John Wiley & Sons, Ltd. [source] Svenzea zeai, a Caribbean reef sponge with a giant larva, and Scopalina ruetzleri: a comparative fine-structural approach to classification (Demospongiae, Halichondrida, Dictyonellidae)INVERTEBRATE BIOLOGY, Issue 3 2003Klaus Rützler Abstract. Svenzea zeai, abundant on many deep Caribbean fore-reef habitats but of uncertain systematic position within the Demospongiae, is closely examined histologically and cytologically for evidence of its phylogenetic relationship beyond the traditional analysis of gross morphology and skeletal structure. We document that S. zeai is a bacteriosponge containing substantial quantities of unicellular photosynthetic and autotrophic microbes; that the most abundant cell type is an unusual cell with refractile granules that only few species share and whose composition and function are still enigmatic; and that it produces the largest,by a factor of 3,embryos and larvae recorded in the phylum Porifera. A combination of characters such as the granular cells, ciliary pattern, and aspects of larval shape and behavior are comparable with those of Scopalina ruetzleri, family Dictyonellidae, a prominent member of the Caribbean mangrove community. These results support our earlier decision to establish Svenzea as a new genus in Dictyonellidae to accommodate its unprecedented skeletal structure, styles in isodictyal reticulation. [source] Exploring complex interactions in designed data using GEMANOVA.JOURNAL OF CHEMOMETRICS, Issue 6 2002Color changes in fresh beef during storage Abstract Data from a severely reduced experimental design are investigated in order to obtain detailed information on important factors affecting the changes in quality of meat during storage under different conditions. It is possible to model the response, meat color, using traditional ANOVA (analysis of variance) techniques, but the exploratory and explanatory value of this model is somewhat restricted owing to the number of factors and the fact that several interactions exist. For those reasons, it is not possible to visualize the model in a simple way and therefore not possible to have a clear overview of the total variation in the data. Using a recently suggested alternative to traditional analysis of variance, GEMANOVA (generalized multiplicative ANOVA), it is possible to analyze the data effectively and obtain a more interpretable solution that enables a simple overview of the whole sampling domain. Whereas traditional analysis of variance typically seeks a model with main effects and as few and simple interactions and cross-products as possible, the GEMANOVA model seeks to describe the data primarily by means of higher-order interactions, albeit in a straightforward way. The two approaches are thus complementary. It is shown that the GEMANOVA model is simple to interpret, primarily because the GEMANOVA structure is in agreement with the nature of the data. It is shown that the GEMANOVA model used is mathematically unique, which leads to attractive simplified ways of interpreting the model. The results presented are the first published results where the GEMANOVA model is not simply equivalent to an ordinary PARAFAC model, thus taking full advantage of the additional structural power of GEMANOVA. A new algorithm for fitting the GEMANOVA model is developed and is available from the authors. Copyright © 2002 John Wiley & Sons, Ltd. [source] Increasing process understanding by analyzing complex interactions in experimental dataJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2009Kaisa Naelapää Abstract There is a recognized need for new approaches to understand unit operations with pharmaceutical relevance. A method for analyzing complex interactions in experimental data is introduced. Higher-order interactions do exist between process parameters, which complicate the interpretation of experimental results. In this study, experiments based on mixed factorial design of coating process were performed. Drug release was analyzed by traditional analysis of variance (ANOVA) and generalized multiplicative ANOVA (GEMANOVA). GEMANOVA modeling is introduced in this study as a new tool for increased understanding of a coating process. It was possible to model the response, that is, the amount of drug released, using both mentioned techniques. However, the ANOVA model was difficult to interpret as several interactions between process parameters existed. In contrast to ANOVA, GEMANOVA is especially suited for modeling complex interactions and making easily understandable models of these. GEMANOVA modeling allowed a simple visualization of the entire experimental space. Furthermore, information was obtained on how relative changes in the settings of process parameters influence the film quality and thereby drug release. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:1852,1861, 2009 [source] Structure of a pseudomerohedrally twinned monoclinic crystal form of a pyridoxal phosphate-dependent catalytic antibodyACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2005Béatrice Golinelli-Pimpaneau The purification, crystallization and structure determination at 2.3,Ĺ resolution of the complex of the pyridoxal-5,-phosphate (PLP) dependent catalytic antibody 15A9 with a phosphopyridoxyl- l -alanine (PPL- l -alanine) substrate analogue are described. The crystal belongs to space group P21, with two molecules in the asymmetric unit related by non-crystallographic symmetry. The unit-cell parameters are a = 63.5, b = 81.7, c = 79.3,Ĺ and , is fortuitously 90°. Refinement of the structure converged at unacceptably high R factors. Although the traditional analysis of intensity distribution did not indicate twinning, pseudomerohedral twinning was revealed by a newer test based on local intensity differences [Padilla & Yeates (2003), Acta Cryst. D59, 1124,1130]. When the potential twinning operator was included in SHELX, the structure could be satisfactorily refined with a twinning fraction of 0.46, indicating a nearly perfect hemihedrally twinned crystal. One of the active sites is occupied by the phosphopyridoxyl- l -alanine ligand, while one iodide ion mimics the cofactor phosphate group in the other. Four other iodide ions are present in the structure: two are involved in specific intermolecular contacts and two dictate the conformation of the CDRH3 loop in each molecule. [source] AN EFFICIENT MODEL FOR ENHANCING TEXT CATEGORIZATION USING SENTENCE SEMANTICSCOMPUTATIONAL INTELLIGENCE, Issue 3 2010Shady Shehata Most of text categorization techniques are based on word and/or phrase analysis of the text. Statistical analysis of a term frequency captures the importance of the term within a document only. However, two terms can have the same frequency in there documents, but one term contributes more to the meaning of its sentences than the other term. Thus, the underlying model should identify terms that capture the semantics of text. In this case, the model can capture terms that present the concepts of the sentence, which leads to discovering the topic of the document. A new concept-based model that analyzes terms on the sentence, document, and corpus levels rather than the traditional analysis of document only is introduced. The concept-based model can effectively discriminate between nonimportant terms with respect to sentence semantics and terms which hold the concepts that represent the sentence meaning. A set of experiments using the proposed concept-based model on different datasets in text categorization is conducted in comparison with the traditional models. The results demonstrate the substantial enhancement of the categorization quality using the sentence-based, document-based and corpus-based concept analysis. [source] | ||||||||||