A5001869460- Spectroscopy and Chemometric Analyses
- Computational Drug Discovery Methods
- Analytical Chemistry and Chromatography
- Meat and Animal Product Quality
- Advanced Chemical Sensor Technologies
- Coffee research and impacts
- Pesticide Residue Analysis and Safety
- Synthesis and biological activity
- Sensory Analysis and Statistical Methods
- Free Radicals and Antioxidants
- Metabolomics and Mass Spectrometry Studies
- HIV/AIDS drug development and treatment
- Advanced Chemical Physics Studies
- Water Quality Monitoring and Analysis
- Phytochemicals and Antioxidant Activities
- Fermentation and Sensory Analysis
- Bioactive Compounds and Antitumor Agents
- Electrochemical Analysis and Applications
- Heavy Metals in Plants
- Agricultural and Food Sciences
- Advanced Statistical Methods and Models
- Crystallography and molecular interactions
- Insect and Pesticide Research
- Inorganic Fluorides and Related Compounds
- Geochemistry and Geologic Mapping
Universidade Estadual de Campinas (UNICAMP)
2013-2023
John Wiley & Sons (United Kingdom)
2018-2023
John Brown University
2018-2023
Universidade Federal do Tocantins
2018
Universidade Federal de Viçosa
2018
Universidade do Estado do Amazonas
2018
Fundação Hospitalar de Hematologia e Hemoterapia do Amazonas
2018
Vale (Brazil)
2009
Universidade Federal de Goiás
2008
Universidade Federal de São Carlos
2008
Four quantitative structure-activity relationships (QSAR) and structure-property relationship (QSPR) data sets were selected from the literature used to build regression models with 75, 56, 50 15 training samples. The validated by leave-one-out crossvalidation, leave-N-out crossvalidation (LNO), external validation, y-randomization bootstrapping. Validations have shown that size of is crucial factor in determining model performance, which deteriorates as set becomes smaller. Models very...
Mathematical models based on chemometric analyses of the coffee beverage sensory data and NIR spectra 51 Arabica roasted samples were generated aiming to predict scores acidity, bitterness, flavour, cleanliness, body overall quality beverage. Partial least squares (PLS) used construct models. The ordered predictor selection (OPS) algorithm was applied select wavelengths for regression model each attribute in order take only significant regions into account. spectrum defined as important...
DESIGN CALCULATIONS, A TUTORIAL.This work describes, through examples, a simple way to carry out experimental design calculations applying an spreadsheets.The aim of this tutorial is introduce alternative sophisticated commercial programs that normally are too complex in data input and output.An overview the principal methods also briefly presented.The spreadsheets suitable handle different types computations such as screening procedures factorial optimization procedure based on response...
Abstract A new procedure with high ability to enhance prediction of multivariate calibration models a small number interpretable variables is presented. The core this methodology sort the from an informative vector, followed by systematic investigation PLS regression aim finding most relevant set comparing cross‐validation parameters obtained. In work, seven main vectors i.e. correlation residual variable influence on projection (VIP), net analyte signal (NAS), covariance procedures vector...
Tomato is an important player in the agricultural market. It second most consumed vegetable world and a source of micronutrients such as lycopene beta-carotene. Recent research has demonstrated that these carotenoids can act free-radical quenchers body prevent aging, tissue damage, heart disease, certain cancers. Besides microcomponents, tomato composed soluble insoluble solids. In industry, solids govern factory yield play major role trade. Nowadays, standard methods for determining are...
The potential of NMR spectroscopy to differentiate honeys concerning the nectar employed in its production was evaluated. application chemometric methods 1H spectra has allowed discriminate produced state São Paulo, being identified signals responsible substances for discrimination. Application PCA and HCA data have resulted natural clustering samples. Wildflower were characterized by higher concentration phenylalanine tyrosine. Citrus showed amounts sucrose than other compounds, while...
ABSTRACT Plants modulate the soil microbiota by root exudation assembling a complex rhizosphere microbiome with organisms spanning different trophic levels. Here, we assessed diversity of bacterial, fungal and cercozoan communities in landraces modern varieties wheat. The dominant taxa within each group were bacterial phyla Proteobacteria, Actinobacteria Acidobacteria; fungi Ascomycota, Chytridiomycota Basidiomycota; Cercozoa classes Sarcomonadea, Thecofilosea Imbricatea. We showed that...
The aim of this work is to present a tutorial on Multivariate Calibration, tool which nowadays necessary in basically most laboratories but very often misused. basic concepts preprocessing, principal component analysis (PCA), regression (PCR) and partial least squares (PLS) are given. two steps any calibration procedure: model building validation fully discussed. cross (to determine the number factors be used model), leverage studentized residuals detect outliers) for step whole procedure...
VARIABLE SELECTION IN QSAR.The process of building mathematical models in quantitative structure-activity relationship (QSAR) studies is generally limited by the size dataset used to select variables from.For huge datasets, task selecting a given number that produces best linear model can be enormous, if not unfeasible.In this case, some methods separate good parameter combinations from bad ones.In paper three methodologies are analyzed: systematic search, genetic algorithm and chemometric...
Summary Pectin was extracted from passion fruit peel using three different acids (citric, hydrochloric or nitric) at temperatures (40–90 °C), pH (1.2–2.6) and extraction times (10–90 min), with without skins a 2 4 factorial design. Temperature, time had highly significant effects on the pectin yield. A central composite design face centring used to optimise process conditions for citric acid skins. yields varied 10% 70%. The optimal maximisation of yield were use 80 °C 1 an 10 min...
This work presents the VALIDATION SPREADSHEET, a public domain tool that can be used to evaluate figures of merit for univariate analytical methods. A real example BTEX determination in environmental samples is included illustrate its use. The spreadsheet has been developed Excel® and Open Office®, available on internet at http//lqta.iqm.unicamp.br.
This study proposes a new approach to discriminate low and full-fat yogurts using instrumental analysis chemometric techniques. One hundred twenty six strawberry flavored were subjected of pH, color firmness. Exploratory methods, such as Principal Component Analysis (PCA) Hierarchical Cluster (HCA), supervised classification K-nearest neighbors (KNN), soft independent modeling class analogy (SIMCA), Partial Least Square Discriminant (PLSDA) used for assessing the data. The results showed...
VALIDATE QSAR MODELS.QSAR modeling is a novel computer program developed to generate and validate or QSPR (quantitative structure-activity property relationships) models.With modeling, users can build partial least squares (PLS) regression models, perform variable selection with the ordered predictors (OPS) algorithm, models by using y-randomization leave-N-out cross validation.An additional new feature outlier detection carried out simultaneous comparison of sample leverage respective...
A novel 4D-QSAR approach which makes use of the molecular dynamics (MD) trajectories and topology information retrieved from GROMACS package is presented in this study. This new methodology, named LQTA-QSAR (LQTA, Laboratório de Quimiometria Teórica e Aplicada), has a module (LQTAgrid) that calculates intermolecular interaction energies at each grid point considering probes all aligned conformations resulting MD simulations. These are independent variables or descriptors employed QSAR...
EVALUATING ANALYTICAL DATA.An activity for introducing hierarchical cluster analysis (HCA) and principal component (PCA) during the Instrumental Analytical Chemistry course is presented.The posed problem involves discrimination of mineral water samples according to their geographical origin.Thirty-seven 9 different brands were considered results from determination Na, K, Mg, Ca, Sr Ba taken into account.Non-supervised methods pattern recognition explored construct a dendrogram, score loading...