Pls Partial Least Squares
Mostrando 13-24 de 178 artigos, teses e dissertações.
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13. Calibration Strategies Applied to Laser-Induced Breakdown Spectroscopy: A Critical Review of Advances and Challenges
Over the years, laser-induced breakdown spectroscopy (LIBS) has been reported in the literature as an alternative to traditional methods of analysis, becoming well established among spectroanalytical techniques. LIBS is a technique widely used for qualitative approaches; however, it is necessary considerable effort for use in quantitative analysis, mainly du
J. Braz. Chem. Soc.. Publicado em: 2020-12
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14. Quick Identification of the Time of Maturation of Artisanal Minas Cheese by FTIR-ATR Spectroscopy and Multivariate Techniques
The objective of this work is the identification of cheese maturation time using attenuated total reflection Fourier transform spectroscopy (FTIR-ATR) data and analytical measurements associated with chemometrics techniques. Minas artisanal cheeses were collected from 8 producers matured at times 1, 7, 14, 21, 28, 45 and 60 days, fractioned in rind and crumb
J. Braz. Chem. Soc.. Publicado em: 2020-10
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15. Omega-3 and Omega-6 Determination in Nile Tilapia’s Fillet Based on MicroNIR Spectroscopy and Multivariate Calibration
Tilapia (Oreochromis niloticus) is the most cultivated fish species in Brazil. Studies have shown that fish consumption is related to the prevention of cardiovascular diseases due to its high contents of polyunsaturated fatty acids, as omega-3 (n-3) and omega-6 (n-6). In this sense, a new method to determine omega-3 and omega-6 by near-infrared (NIR) spectro
J. Braz. Chem. Soc.. Publicado em: 2020-09
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16. Determination of Ethanol in Gel Hand Sanitizers Using Mid and Near Infrared Spectroscopy
Alcohol-based gel hand sanitizers became very popular during the COVID-19 (coronavirus disease 2019) pandemic. In Brazil, several irregular factories emerged requiring an efficient control by the police and regulatory agencies to guarantee product quality. This problem required a method to determine ethanol content, which led to the development of two method
J. Braz. Chem. Soc.. Publicado em: 2020-09
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17. A multivariate approach to differentiate yerba mate (Ilex paraguariensis) commercialized in the southern Brazil on the basis of phenolics, methylxanthines and in vitro antioxidant activity
Abstract The consumption of yerba mate beverages is related to several health benefits. These desirable properties are mainly due to the bioactive compounds. However, the levels of those compounds are directly affected by factors such as geographical origin. This study aimed to use chemometrics to evaluate the antioxidant compounds of yerba mate (consumed as
Food Sci. Technol. Publicado em: 2020-09
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18. 1H NMR and Chemometric Methods to Estimate the Octane Number in Brazilian C Gasolines
Brazilian gasoline type C can be purchased with octane number as the main difference. This quality parameter directly affects the price. Intermediate formulations may not be easily distinguished from conform samples due to similarity in visual appearance and physicochemical properties. The use of anhydrous ethanol as an additive also influences the octane va
J. Braz. Chem. Soc.. Publicado em: 2020-08
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19. REGRESSÃO MULTIVARIADA POR OPLS E PLS DOS ESPECTROS DE RMN DE 1H DE MISTURAS DIESEL/BIODIESEL DE MAFURRA PARA ESTIMATIVA DO TEOR DE BIODIESEL
Two methodologies were developed to monitor the biodiesel content of mafurra in mixtures with diesel using hydrogen nuclear magnetic resonance (1H NMR) Spectroscopy combined with the multivariate regression by orthogonal projections to latent structure (OPLS) and partial least squares (PLS). The efficiency of these methodologies was analyzed based on the fig
Quím. Nova. Publicado em: 20/07/2020
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20. DETERMINAÇÃO DA AUTENTICIDADE DE AMOSTRAS DE AZEITE COMERCIAIS APREENDIDAS NO ESTADO DO ESPÍRITO SANTO USANDO UM ESPECTROFOTÔMETRO PORTÁTIL NA REGIÃO DO NIR
Many instrumental techniques are used to monitor the quality of food products, highlighting near infrared spectroscopy (NIRS). In order to determine the authenticity of 60 commercial oil samples seized by the Espírito Santo state police, this work used a portable spectrometer in the NIR region associated with chemometric tools such as principal component an
Quím. Nova. Publicado em: 20/07/2020
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21. Fast Verification of Buffalo’s Milk Authenticity by Mid-Infrared Spectroscopy, Analytical Measurements and Multivariate Calibration
Mid-infrared spectroscopy (MID), chemical composition and physicochemical characteristics associated with chemometrics were used to rapidly detect and quantify the amount of cow’s milk added in buffalo’s milk. A total of 165 samples, divided into buffalo’s milk, buffalo’s milk added with cow’s milk (10 to 90%) and cow’s milk were evaluated to obt
J. Braz. Chem. Soc.. Publicado em: 2020-07
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22. Double or triple-expressor lymphomas: prognostic impact of immunohistochemistry in patients with diffuse large B-cell lymphoma
Mid-Infrared absorption spectroscopy associate with the Partial Least Squares regression is the official method to monitor Brazilian commercial diesel quality. This method, however, uses solvents and a large number of samples for the construction of the calibration curves, which generates waste and increases the time needed for the analysis. In order to deve
Hematol., Transfus. Cell Ther.. Publicado em: 2020-06
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23. QUANTIFICAÇÃO DO TEOR DE BIODIESEL DE CRAMBE EM MISTURAS COM DIESEL UTILIZANDO ESPECTROSCOPIA MIR E SELEÇÃO DE VARIÁVEIS
Mid-Infrared absorption spectroscopy associate with the Partial Least Squares regression is the official method to monitor Brazilian commercial diesel quality. This method, however, uses solvents and a large number of samples for the construction of the calibration curves, which generates waste and increases the time needed for the analysis. In order to deve
Quím. Nova. Publicado em: 2020-06
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24. EXPERIMENTO DIDÁTICO DE QUIMIOMETRIA PARA CLASSIFICAÇÃO DE ÓLEOS VEGETAIS COMESTÍVEIS POR ESPECTROSCOPIA NO INFRAVERMELHO MÉDIO COMBINADO COM ANÁLISE DISCRIMINANTE POR MÍNIMOS QUADRADOS PARCIAIS: UM TUTORIAL, PARTE V
A teaching experiment on supervised pattern recognition in chemometrics was proposed in this tutorial to introduce partial least squares discriminant analysis (PLS-DA). A new approach of the experiment published in the first tutorial of this series was revisited and employed to the classification of edible vegetable oils. The spectra of olive, canola, soybea
Quím. Nova. Publicado em: 2020-03