Method M K
Mostrando 13-24 de 1134 artigos, teses e dissertações.
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13. Perovskite-Type Oxides La0.6M0.4Ni0.6Cu0.4O3 (M = Ag, Ba, Ce) towards the Oxygen Reduction Reaction (ORR) in Alkaline Medium: Structural Aspects and Electrocatalytic Activity
In this work, La0.6M0.4Ni0.6Cu0.4O3 (M = Ag, Ba, and Ce, denoted as LANC, LBNC, and LCNC, respectively) electrocatalysts were synthesized by the Pechini method at 1023 K for two hours in air. Rietveld refinement allowed the identification of the crystallographic phases present in all oxides. The electrocatalytic performance of these oxides towards the oxygen
J. Braz. Chem. Soc.. Publicado em: 2021-03
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14. SEQUENTIAL MULTI-ELEMENT DETERMINATION OF TRACE-METALS IN BIODIESEL SAMPLES USING HR-CS FAAS
In this work the feasibility of sequential multi-element determination of Zn, Fe, Mg, Cu, Na, K, Cr, Al and Ca in biodiesel samples by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was investigated. Biodiesel samples obtained from different sources and different chemical processes were analysed. The samples were diluted w
Quím. Nova. Publicado em: 2021-02
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15. Mineral Nutrients and Plant-Fungal Interaction in Cocoa Trees (Theobroma cacao L.)
An infection of the fungus Moniliophthora perniciosa in cocoa trees reduces productivity of the plant. In this study, the concentrations of mineral nutrients in healthy leaves and in leaves of vegetative broom of the cocoa plant were determined, and the relationship between the disease and the nutritional composition of the leaves was assessed. The samples w
J. Braz. Chem. Soc.. Publicado em: 2021-02
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16. Rapid and Inexpensive Colorimetric Detection of Total Serum Protein Using Microzone Plates Wax-Printed on Polyester Films
This report describes a rapid and inexpensive colorimetric method based on biuret assay for total serum protein analysis using wax printed microzone plates and a desktop scanner. The colorimetric assay was performed in 96-microzone plates fabricated on polyester films through a wax printing protocol. The image scanning mode and the concentration of the biure
J. Braz. Chem. Soc.. Publicado em: 2021-02
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17. An Efficient and Recyclable Sn-Based Phosphotungstic Acid with Tunable Brønsted/Lewis Acidity for Selective Oxidation of Benzyl Alcohol
A series of metal ion (M = Sn2+, Fe3+, Ni2+, Co2+, Ag+, Cu2+) exchanged tungstophosphoric acid (H3PW12O40; TPA) catalysts with tunable Brønsted/Lewis acidity were synthesized and exploited for the oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) using hydrogen peroxide (H2O2) as oxidant. The structure of these M-TPA composite salts was also characte
J. Braz. Chem. Soc.. Publicado em: 2021-01
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18. Study of Inorganic Profiles of Street Cocaine Samples Using ICP-MS and ICP OES
Determining inorganic constituents in illicit drugs can indicate its purity and presence of adulterants. In this study, we analyzed 52 street cocaine samples, seized in three different regions of Espírito Santo, state of Brazil. Inductively coupled plasma optical emission spectrometry was used to determine Al, Ca, Cu, Fe, Mn, Mg, Zn concentrations and induc
J. Braz. Chem. Soc.. Publicado em: 2021-01
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19. X-ray Scattering and Chemometrics as Tools to Assist in the Identification of Gunshot Residues by Wavelength Dispersive X-ray Fluorescence Spectrometry
Wavelength dispersion X-ray fluorescence spectrometry (WDXRF) is a non-destructive technique and therefore attractive for gunshot residues (GSR) analysis. It is well known for determination of inorganic constituents of samples. However, X-ray scattering region spectral data is not commonly used, although it may provide information about organic constituents
J. Braz. Chem. Soc.. Publicado em: 2020-12
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20. THERMODYNAMIC PROPERTIES OF TAMARIND SEEDS (Tamarindus indica L.)
ABSTRACT Tamarind is used in the food and pharmaceutical industry, and its seed is the main means for the reproduction of this species, thus justifying studies that ensure its post-harvest viability. This research aimed to study the thermodynamic properties of tamarind seeds as a function of the equilibrium moisture content. The experimental data of the wate
Eng. Agríc.. Publicado em: 2020-12
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21. HPLC METHOD IMPROVEMENT FOR 4-NONYLPHENOL DETERMINATION IN ANAEROBIC REACTORS: DECREASING SOLVENT CONSUMPTION AND WASTE GENERATION
The aim of this study was to develop a chromatographic method for 4-NP determination in anaerobic batch reactors using low amount of organic solvents and also evaluate 4-NP degradation in the presence of different co-substrates. Chromatographic parameters was improved for stationary phase (C-8 column), mobile phase (acetonitrile/water solution 90:10, v:v), c
Quím. Nova. Publicado em: 2020-09
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22. CONSTITUENTS FROM ROOTS OF Maytenus distichophylla, ANTIMICROBIAL ACTIVITY AND TOXICITY FOR CELLS AND Caenorhabditis elegans
Maytenus distichophylla is a medicinal species used in Northeast of Brazil. The hexane (HE), chloroform (CE), ethyl acetate (EAE) and methanol (ME) extracts and compounds from its roots were evaluated for their protective activity against Staphylococcus aureus and Candida albicans. The cytotoxicity for chronic myeloid leukemia (K562), acute monocytic leukemi
Quím. Nova. Publicado em: 2020-09
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23. USE OF AIC AND BIC IN DESORPTION ISOTHERMS OF TAMARIND SEEDS (Tamarindus indica L.)
ABSTRACT The knowledge of hygroscopicity is essential for the storage of tamarind seeds, but there is a limitation of a judicious statistical parameter to define the best mathematical model to adjust the isotherms of plant products. Therefore, this study aimed to determine the desorption isotherms of tamarind seeds and test the Akaike information criterion (
Eng. Agríc.. Publicado em: 2020-08
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24. Application of Mixture Design Using Diluted Acid for Extraction of Inorganic Components in Fruits of Casearia fasciculata and Determination by ICP OES: Evaluation by PCA and HCA
This study is the first to propose the simultaneous quantification of 10 elements in fruits of Casearia fasciculata by inductively coupled plasma optical emission spectrometry (ICP OES). A method of digestion using dilute nitric acid was optimized by mixture design for extraction of elements in the seed, peel, and pulp of Casearia fasciculata cultivated in t
J. Braz. Chem. Soc.. Publicado em: 2020-06