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Mostrando 25-36 de 7879 artigos, teses e dissertações.
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25. Chemoenzymatic Synthesis of Apremilast: A Study Using Ketoreductases and Lipases
The key step in the chemoenzymatic synthesis of apremilast was to produce the chiral alcohol (R)-1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethanol, (R)-3. Two enzymatic approaches were evaluated to obtain (R)-3, one using ketoreductases and the other lipases. Bioreduction of 1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethanone (2), using ketoreductas
J. Braz. Chem. Soc.. Publicado em: 2021-05
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26. MODIFICAÇÃO QUÍMICA DO POLIPROPILENO ATRAVÉS DA INTRODUÇÃO DE GRUPOS SULFÔNICOS PARA APLICAÇÃO COMO CATALISADOR EM REAÇÕES DE ESTERIFICAÇÃO
In this work, the chemical modification of pristine polypropylene was carried out through sulfonation reactions with concentrated sulfuric acid (PPS1) and fuming sulfuric acid (PPS2), for production of heterogeneous catalysts used in esterification reactions. Fourier transform infrared spectroscopy, elemental analysis, degree of substitution and ion exchange
Quím. Nova. Publicado em: 2021-04
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27. New Greener Method for the Preparation of Heteropolyacid Compounds (HPW) Modified with Metallic Tin and Application in the Lactic Acid Esterification Reaction
The main objective of this work was to design an innovative method to prepare heterogeneous heteropolyacid catalysts. The heteropolyacid H3PW12O40 (HPW) was modified with tin(II) by two methodologies: a conventional aqueous ion-exchange (CS) and a redox solid-state (SS). In both cases, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD
J. Braz. Chem. Soc.. Publicado em: 2021-03
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28. HSCCC Separations of Rutin Esters Obtained by Enzymatic Reaction Catalyzed by Lipase
The flavonoid rutin presents several pharmacological effects, despite this, its application in the pharmaceutical industry can be significantly limited by its low bioavailability. The development of lipophilic derivatives by esterification of hydroxyl groups with fatty acid chains may be an effective strategy to change their physicochemical properties. This
J. Braz. Chem. Soc.. Publicado em: 2021-03
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29. Conversion of vesicostomy into continent catheterizable reservoirs in myelomeningocele
ABSTRACT Introduction: Vesicostomy should be considered in children with neuropathic bladder in case first-line therapies fail. This simple and reversible procedure can reduce febrile urinary tract infections and protect the upper urinary tract (1) until more definitive alternatives can be proposed. We describe in this video how we approach patients that un
Int. braz j urol.. Publicado em: 2021-03
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30. Properties of Cu-Co Composite Catalysts for Synthesis of Aliphatic Alcohols
Cu-Co-containing cellulose-based carbon composite materials (Cu-Co/Cel) were formed by a matrix isolation method. Using X-ray diffraction (XRD), transmission electron microscopy (TEM), infrared-Fourier spectroscopy (IR-Fourier spectroscopy), and non-isothermal research methods, the physicochemical properties of the composites were established. The catalysts
J. Braz. Chem. Soc.. Publicado em: 2021-02
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31. Er3+/Yb3+-Doped GdVO4 Obtained by the Non-Hydrolytic Sol-Gel Route and Potential Application as Up-Conversion Thermometer
The properties of lanthanides allow them to be used as contrast agents for magnetic resonance imaging, thereby helping to differentiate between tissues, organs, and pathologies more efficiently. Lanthanides contain thermosensitive energy levels that aid identification of cancer and healthy cells. This work investigates the GdVO4 matrix obtained by the non-hy
J. Braz. Chem. Soc.. Publicado em: 2021-02
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32. AN EVALUATION OF THE THERMAL AND LUMINOUS ENVIRONMENT OF LAYING HEN AVIARIES EQUIPPED WITH LIGHT-EMITTING DIODE AND COMPACT FLUORESCENT LAMPS AND THEIR EFFECTS ON PRODUCTION AND EGG QUALITY
ABSTRACT The thermal and luminous conditions in aviaries affect the production and quality of eggs. Thus, the aim of the present study was to evaluate the thermal and luminous environment of commercial laying hen aviaries equipped with compact fluorescent (CF) and light-emitting diode (LED) lamps and their influence on egg production and quality. The study w
Eng. Agríc.. Publicado em: 2021-02
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33. Oxygen Inhibition of Surface Composites and Its Correlation with Degree of Conversion and Color Stability
Resumo Este estudo investigou os efeitos da inibição de oxigênio e dos procedimentos de acabamento/polimento nas propriedades das resinas compostas. Foram avaliadas uma resina composta bulk fill e duas resinas convencionais (nanoparticulada e microhíbrida). Os espécimes foram confeccionados, variando o tratamento de superfície: controle, sem tratamento
Braz. Dent. J.. Publicado em: 2021-02
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34. Optimization of the Reaction Conditions for the Synthesis of Dihydrobenzofuran Neolignans
We have optimized the experimental conditions for the silver(I)-promoted oxidative coupling of methyl p-coumarate (I) and methyl ferulate (II), which is the most frequently used methodology to synthesize the bioactive dihydrobenzofuran neolignans 1 ((±)-trans-dehydrodicoumarate dimethyl ester) and 2 ((±)-trans-dehydrodiferulate dimethyl ester). Most of the
J. Braz. Chem. Soc.. Publicado em: 2021-01
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35. Abscesso retrofaríngeo complicado: uma causa atípica de mielopatia
In order to increase the specific surface area of Pt-Rh-Pd / Al2O3 automotive three-way catalyst and improve its low-temperature reduction performance, Ce, Zr, and La were added to the Pt-Rh-Pd / Al2O3 catalyst to prepare the fibrous Pt-Rh-Pd / CeO2-ZrO2-La2O3-Al2O3 catalyst via an electrospinning technique. The fibrous catalysts were characterized by XRD, F
Arq. Neuro-Psiquiatr.. Publicado em: 2021-01
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36. Falha do Solitaire Stent retriever durante a trombectomia: há alguma imagem que pode predizer a não recanalização?
In order to increase the specific surface area of Pt-Rh-Pd / Al2O3 automotive three-way catalyst and improve its low-temperature reduction performance, Ce, Zr, and La were added to the Pt-Rh-Pd / Al2O3 catalyst to prepare the fibrous Pt-Rh-Pd / CeO2-ZrO2-La2O3-Al2O3 catalyst via an electrospinning technique. The fibrous catalysts were characterized by XRD, F
Arq. Neuro-Psiquiatr.. Publicado em: 2021-01