Spectrometer
Mostrando 13-24 de 443 artigos, teses e dissertações.
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13. 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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14. Chemical Prospection of Qualea grandiflora Mart. Fruit and Stem Extracts and Their in vitro and in vivo Antiplasmodial Activity
Qualea grandiflora Mart. (“pau-terra”) is a medicinal plant symbolic from Cerrado biome. Qualea species reportedly have antiparasitic properties, but their active compounds have yet to be identified. In this study, we investigated the antiplasmodial activity of Q. grandiflora fruit and stem extracts against Plasmodium falciparum. The polar extracts of bo
J. Braz. Chem. Soc.. Publicado em: 2020-07
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15. Stability Indicating Method for Determination of Benznidazole and Its Degradation Products in Active Pharmaceutical Ingredient
Currently, treatment of Chagas disease is restricted to the use of benznidazole and nifurtimox; however, nifurtimox was temporarily suspended in some countries. Based on the limitations in pharmacological treatments, it is essential to guarantee the quality of benznidazole. Therefore, this work aimed to identify the degradation products of benznidazole and t
J. Braz. Chem. Soc.. Publicado em: 2020-06
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16. 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
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17. Quantification of Glyphosate and AMPA by HPLC-ICP-MS/MS and HPLC-DAD: A Comparative Study
In this work, the direct determination methodology of glyphosate and aminomethylphosphonic acid (AMPA) by high performance liquid chromatography (HPLC) using inductively coupled plasma with triple quadrupole mass spectrometer (ICP-MS/MS) was compared with the conventional method using diode array detector (HPLC-DAD). Both methods were selective, but the chro
J. Braz. Chem. Soc.. Publicado em: 2020-02
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18. Anti-Biofilm and Hemolytic Effects of Cymbopogon citratus (Dc) Stapf Essential Oil
Abstract Objective: To perform chemical analysis and to evaluate the anti-biofilm and hemolytic effect of the essential oil of Cymbopogon citratus. Material and Methods: Gaseous chromatography coupled to mass spectrometer was performed for chemical characterization of the essential oil. To verify the antimicrobial action, the Minimum Inhibitory Concentrati
Pesqui. Bras. Odontopediatria Clín. Integr.. Publicado em: 13/01/2020
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19. Preference of Neoseiulus californicus (Acari: Phytoseiidae) for volatiles of Bt maize induced by multiple herbivory
ABSTRACT Plant indirect induced defenses against herbivores are characterized by the production of plant volatiles that to attract natural enemies. The objective of this study was to evaluate whether the attack of the two-spotted spider mite Tetranychus urticae or the multiple herbivory of T. urticae together with the fall armyworm Spodoptera frugiperda are
Rev. Bras. entomol.. Publicado em: 13/01/2020
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20. DEVELOPING NEAR INFRARED SPECTROSCOPIC MODELS FOR PREDICTING DENSITY OF Eucalyptus WOOD BASED ON INDIRECT MEASUREMENT
ABSTRACT The objective of this study was to establish multivariate models for the prediction of wood basic density with reference to the values of average density of trees and near infrared (NIR) spectra measured in the breast height. The wood basic density of 39 Eucalyptus clones was determined in the laboratory by means of the mean longitudinal positions o
CERNE. Publicado em: 20/12/2019
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21. Effect of Rolling Reduction and Temperature on the Oxide Scale of Hot Rolled Mild Steel Strip
Hot rolling experiments were designed to investigate the effect of rolling temperature and rolling deformation on microstructure, thickness and surface red scale of hot rolled mild steel oxide scale by spectrometer, SEM and pickling experiment. The research results show that in the same other experiment conditions, the greater the rolling deformation, the th
Mat. Res.. Publicado em: 04/11/2019
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22. Determination of Amino Acids in Plasma Samples of Preeclampsia Patients by Liquid Chromatography Coupled to High-Resolution Mass Spectrometry
This work presents the application of a simple and sensitive method developed for the simultaneous analysis of the levels of twenty two underivatizated free L-amino acids in plasma samples of preeclampsia patients by high performance liquid chromatography coupled to high-resolution mass spectrometer (LC-HRMS) using hydrophilic interaction liquid chromatograp
J. Braz. Chem. Soc.. Publicado em: 21/10/2019
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23. Antileishmanial activity and chemical composition from Brazilian geopropolis produced by stingless bee Melipona fasciculata
ABSTRACT Geopropolis is produced by some stingless bee species such as Melipona fasciculata and consists of a mixture of plant resins, salivary secretions of the bee, wax, and soil. This study evaluated the antileishmanial activity in vitro, cytotoxicity and chemical composition of geopropolis produced by M. fasciculata in the savannah region of Maranhão, B
Rev. bras. farmacogn.. Publicado em: 26/08/2019
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24. The role of seasonality on the chemical composition, antioxidant activity and cytotoxicity of Polish propolis in human erythrocytes
ABSTRACT Propolis extracts possess beneficial biological effects, such as antioxidant activity. However, the composition of propolis and biological properties of its extracts depend on many factor, including time of harvesting. The main purpose of this study was to evaluate the seasonal effect on the phenolic profile of Polish propolis extracts and their ant
Rev. bras. farmacogn.. Publicado em: 26/08/2019