Search results for "multivariate statistic"
showing 10 items of 327 documents
Multivariate quality control studies applied to Ca(II) and Mg(II) determination by a portable method
1998
Made available in DSpace on 2022-04-28T19:53:14Z (GMT). No. of bitstreams: 0 Previous issue date: 1998-01-01 A portable or field test method for simultaneous spectrophotometric determination of calcium and magnesium in water using multivariate partial least squares (PLS) calibration methods is proposed. The method is based on the reaction between the analytes and methylthymol blue at pH 11. The spectral information was used as the X-block and the Ca(II) and Mg(II) concentrations obtained by a reference technique (ICP-AES) were used as the Y-block. Two series of analyses were performed, with a month's difference between them. The first series was used as the calibration set and the second on…
Immunonutritive Scoring for Patients with Hepatocellular Carcinoma Undergoing Transarterial Chemoembolization: Evaluation of the CALLY Index
2021
The novel CRP–albumin–lymphocyte (CALLY) index is an improved immunonutritive scoring system, based on serum C-reactive protein (CRP), serum albumin, and the lymphocyte count. It has shown promise as a prognostic index for patients with hepatocellular carcinoma (HCC) undergoing resections. This study evaluated the prognostic ability of the CALLY index for patients with HCC undergoing transarterial chemoembolization (TACE). We retrospectively identified 280 treatment-naïve patients with HCC that underwent an initial TACE at our institution, between 2010 and 2020. We compared the CALLY index to established risk factors in univariate and multivariate regression analyses for associations with m…
Immunonutritive Scoring in Patients With Hepatocellular Carcinoma Undergoing Transarterial Chemoembolization: Prognostic Nutritional Index or Control…
2021
ObjectivesThe Prognostic Nutritional Index (PNI) and Controlling Nutritional Status (CONUT) score are immunonutritive scoring systems with proven predictive ability in various cancer entities, including hepatocellular carcinoma (HCC). We performed the first evaluation of the CONUT score for patients undergoing transarterial chemoembolization (TACE) and compared CONUT and PNI in the ability to predict median overall survival (OS).MethodsBetween 2010 and 2020, we retrospectively identified 237 treatment-naïve patients with HCC who underwent initial TACE at our institution. Both scores include the albumin level and total lymphocyte count. The CONUT additionally includes the cholesterol level. …
Assessing complexity and causality in heart period variability through a model-free data-driven multivariate approach
2017
The aim of this study is to emphasize the importance of model-free data-driven mul- tivariate approaches in describing HP variability and cardiovascular control mechanisms responsible for inducing HP changes via modifications of different cardiovascular vari- ables such as SAP and RESP. The goal was achieved through the application, a previously proposed model-free data-driven multivariate framework devised to assess complexity and causality over a multivariate set composed by several, simultaneously recorded, car- diovascular variability series (Porta et al., 2014). The approach was applied to assess the complexity of the cardiac control, through the evaluation of the amount of irregularit…
Predictive value of morphologic parameters for successful correction of Class II Division 2 malocclusion
2003
Abstract The aim of this study was to assess the predictive value of pretreatment cephalometric parameters and apical base size for successful correction of Angle Class II Division 2 malocclusion. Pretreatment lateral cephalograms and pretreatment and posttreatment study casts of 96 subjects with Class II Division 2 malocclusions were examined to obtain 23 cephalometric parameters and to measure the size of the apical bases. Success of occlusal correction was evaluated as the percentage of change of peer assessment rating scores during treatment; percentage of change was the dependent variable in multivariate statistical analyses used to test the predictive value of the assessed parameters.…
Archaeometry of Sicilian glazed pottery
2004
Petrographic and chemical analyses of the “ceramic body” of 114 majolica artefacts manufactured in Sicily over a wide time range (16th–-19th century) are presented. All the analysed samples, which belong to museums and private collections, were previously attributed to Sicilian workshops based on stylistic features evaluated by expert historians of art. Unambiguous identification of the production sites of majolica handicrafts in Sicily remains, however, open to question when this relies only on purely stylistic considerations. To this end compositional and/or textural markers have been searched for in the “ceramic body” of the majolica artefacts in order to differentiate between the centre…
FEEDFORWARD CONTROL SCHEMES FOR CHEMICAL PROCESSES: AN ALGORITHMIC APPROACH
1983
Abstract A procedure for the systematic determination of feedforward control schemes for chemical processes is presented and an algorithm is derived. The proposed method makes use of the structural features of the process to be controlled and can be applied to linearized process models. Worked examples show how the algorithm can be a handy tool that systemizes the choice of manipulative and measuring variables in feedforward control schemes for multivariate processes.
Multivariate data analysis and bivariate regression studies applied to comparison of two multi-elemental methods for analysing wine samples
2002
Two inductively coupled plasma mass spectrometry (ICP-MS) methods which permit multi-elemental analysis in wine samples have been compared following two strategies. First, a multivariate tool based on principal component analysis (PCA) was employed for a global (all analytes) qualitative comparison of the two methods. A single plot based on the confidence limits of the Q and T2 PCA model statistics corresponding to the ‘standard’ method results (calibration set) was used to check the comparability of the ‘candidate’ method (test samples). The residual matrix (after test matrix interpolation into the PCA model) gives qualitative information about the nature of the main errors. This approach …
Net analyte signal as a deconvolution-oriented resolution criterion in the optimisation of chromatographic techniques
2003
The performance of two multivariate calibration measurements, multivariate selectivity (SEL(s)) and scalar net analyte signal (scalar NAS), as chromatographic objective functions (COFs), was investigated. Since both assessments are straightforwardly related to the quantification of analytes in the presence of interferents, they were expected to confer new features in the optimisation of compound resolution, not present in conventional assessments. These capabilities are especially interesting in situations of low resolution, where peak deconvolution becomes an attractive alternative. For comparison purposes, chromatographic resolution (R(s)) and peak purity (p(s)) were used as reference COF…
Identification of compounds responsible for the odorant properties of aromatic caramel
2012
Aromatic caramel results from the heat treatment of sugars under specific temperature conditions. Because of its richness in aroma compounds and its pleasant organoleptic properties, caramel is widely used in the food industry. However, the composition of the volatile odorant fraction has not been completely elucidated. The aim of this work was thus to identify the volatile odorant compounds responsible for caramel sensory properties using a multivariate statistical technique. Four aromatic caramels differing in terms of their carbohydrate composition and cooking process were chosen. Odorant compounds were screened by gas chromatography–olfactometry (GC-O) and identified by GC–mass spectrom…