. The growth of biodiesel market and the implementation of regulations related to biodiesel production and biodiesel/diesel blending has encouraged the development of appropriate analytical methods to control the composition of this type of mixture. In this study, an evaluation of the potential of GC×GC for the characterization of samples of beef tallow biodiesel and the composition of blends of biodiesel/ diesel is presented. The methodology was applied to beef tallow biodiesel and its mixtures with petrodiesel, ranging from B2 to B50. Results allowed not only the identification and quantification of the biodiesel esters, but also the biodiesel percentage in biodiesel/ diesel blends.Keywords: biodiesel/diesel blends; GCxGC; FAME. INTRODUÇÃOOs recursos energéticos renováveis, em suas mais diversas formas, têm sido bastante estudados e são considerados componentes importantes na busca de uma economia energética sustentável. [1][2][3][4] Dentre estes novos combustíveis, o biodiesel desponta como uma da melhores alternativas ao petrodiesel.5-9 O biodiesel é produzido a partir de óleos vegetais e/ou gorduras animais, ambos puros ou residuais, através da reação de transesterificação ou esterificação catalítica com álcool de baixa massa molecular.10-14 O biodiesel não apresenta em sua composição compostos como enxofre, hidrocarbonetos aromáticos, metais ou resíduos de óleo bruto, porém apresenta propriedades que podem melhorar o perfil de emissões de poluentes. 15,16 Além disso, este biocombustível pode ser usado em motores a diesel convencionais sem necessitar de modificações significativas. 11,12A composição do diesel e de misturas diesel/biodiesel influencia diretamente algumas propriedades como densidade, viscosidade e volatilidade, principalmente quando se trabalha em temperaturas baixas. 11Por norma da ANP (Agência Nacional de Petróleo, Gás e Biocombustíveis), o biodiesel deve ser usado em misturas com o diesel petroquímico (BX), sendo atualmente usada a mistura B5, ou seja, 5% de biodiesel em 95% de diesel. Entretanto, para uso próprio, e baseado em testes já descritos na literatura, podem ser usados teores maiores de biodiesel, sem danos representativos ao motor e sem perda de eficiência. 10,11A Norma ABNT NBR15568 estabelece um método para a determinação do percentual de biodiesel na mistura com diesel usando espectroscopia na região do infravermelho (IR) nas faixas de concentração entre 0,5 e 30%. Entretanto, para a melhor fiscalização destas misturas é necessário um método rápido que permita a total caracterização do biodiesel (identificação e quantificação dos ésteres metílicos) e a quantificação deste na mistura com diesel, além de possibilitar a caracterização de outros adulterantes utilizados.A cromatografia gasosa acoplada à espectrometria de massas com monitoramento seletivo de íons permite a identificação dos ésteres na mistura biodiesel/diesel, porém sua quantificação na mistura fica prejudicada pela coeluição com os hidrocarbonetos do diesel. Já a cromatografia gasosa bidimensional abrangente (GC×G...
não acontece, o objetivo torna-se minimizar o alastramento e diminuir a gravidade das consequências.
We describe herein the organocatalyzed synthesis and preliminary results of antioxidant activities of a range of 1,2,3-triazoylzidovudine derivatives. These hybrid compounds were synthesized in moderate to excellent yields by reacting zidovudine 1 with a variety of functionalized keto compounds 2, such as βketo-esters, β-diketones, β-keto-amides, α-keto-nitriles, and βketo-sulfones, in the presence of a catalytic amount of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) (10 mol %). Furthermore, the synthesized compounds were screened for their in vitro antioxidant activity. Compounds 3 a, 3 d, 3 g, and 3 l inhibited the formation of reactive oxygen species (ROS) and lipid peroxidation in the prefrontal cortex and hippocampus of mice with similar potency and efficacy.
Background: Developing methods to synthesize highly functionalized and complex 1,2,3-triazoles from various combinations of substrates remains a significant challenge in organic synthesis. Thus, to the best of our knowledge, an organocatalytic approach to synthesize 1,2,3-triazoles derived from fatty acids has not been explored. Objective: In this sense, we describe here the organocatalyzed synthesis and preliminary results of antitumor and cytotoxic activity of a range of 1,2,3-triazoles derived from fatty esters. Methods: To synthesize 1,2,3-triazoles 3 derived from fatty β-ketoesters, we performed the reaction of appropriate aryl azides 2a-j with β-ketoesters 1a-c in the presence of 5 mol% of DBU using DMSO as a solvent at 70 °C for 24 h. The viability of 5637 cells was determined by measuring the reduction of soluble MTT to water-insoluble formazan. The IC50 concentration that inhibits 50% of cell growth and the results were obtained by at least three independent experiments in triplicate for each test. Results: Through enolate-mediated organocatalysis, 1,2,3-triazoles 3 derived from fatty β-ketoesters were synthesized in moderate to excellent yields by reacting fatty esters 1 with aryl azides 2 in the presence of a catalytic amount of 1,8-diazabicyclo[5.4.0]undec-7-ene (5 mol%). All compounds derived from palmitic acetoacetate 1a were evaluated regarding induced cytotoxicity in vitro in a human bladder cancer cell line, and compounds 3a, 3d, 3e, and 3g were shown to be promising alternatives for bladder cancer treatment and presented the lowest inhibitory concentration of IC50. Conclusion: We described a synthetic procedure to prepare 1,2,3-triazoles derived from fatty β-ketoesters by DBU-catalyzed 1,3-dipolar cycloaddition reactions of fatty esters with different aryl azides. Compounds derived from palmitic acetoacetate were screened for antitumor and cytotoxic activity in vitro in human bladder cancer cell lines, and compounds 3a, 3d, 3e, and 3g showed potential to treat bladder cancer.
O artigo avaliou as características dos bolsistas de Produtividade em Pesquisa da grande área Ciências da Saúde do Conselho Nacional de Desenvolvimento Científico e Tecnológico. Aplicaram-se indicadores bibliométricos e cientométricos e indicadores adicionais de perfil junto a 1.634 pesquisadores com bolsa vigente em 2021. Os dados foram coletados no Conselho Nacional de Desenvolvimento Científico e Tecnológico e no Currículo Lattes. Constatou-se maior número de bolsistas no Comitê de Assessoramento da Medicina, no nível 2 e na região Sudeste. Os percentuais de bolsistas dos sexos feminino e masculino foram similares. Além disso, identificou-se diferença na distribuição do número de artigos entre os seis Comitês e o número de artigos influenciou no nível de bolsa recebida, visto que os bolsistas 1A foram mais produtivos em comparação com os dos demais níveis. Traz contribuições para políticas públicas em Ciência e Tecnologia e para o campo ao avaliar a grande área Ciências da Saúde de modo integral a partir de indicadores diversificados.
Influenza is an acute infection of the respiratory system usually self-limiting, evolving towards complete cure due to the immunological response of the infected organism, but that can have serious complications, such as pneumonia and death. It is a disease widely distributed around the world, associated with several pandemics for over a century. The most recent pandemic occurred in 2009, when a new strain of influenza A (H1N1) virus caused an outbreak in Veracruz, Mexico, and rapidly spread though all the continents, causing over 12 thousand deaths in less than a year. Considering that this new strain of the virus is only sensitive to neuraminidase inhibitors (oseltamivir and zanamivir) and that the protocol of the World Health Organization recommends the use of oseltamivir as a single drug therapy, this study was performed with the intention of collecting and compiling data about the occurrence of resistance to this medication, in particular due to a H274Y substitution. In addition to mapping the occurrence of resistant virus, data was also collect about the person-to-person transmission of the virus with the mutation H274Y, as well as about the association of the appearance of resistance with the use of the drug.
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