161 research outputs found
National postgraduate system (SNPG) and chemistry area at the brazilian federal agency for post-graduate education (CAPES)
The Coordination for the Improvement of High Education Personnel (CAPES), the Brazilian federal agency for graduate programs, plays a fundamental role for the expansion and consolidation of the National Postgraduate System (SNPG) and the execution of the National Graduate Plan (PNPG) 2011-2020. In this paper, we discuss the evolution of the Brazilian graduate program in chemistry and its role in the formation of highly qualified professionals in chemistry (academic master’s degree, professional master’s degree and doctoral degree) for the academy, teachers and lecturers for all levels of the education system, as well for the non-academic market
MULHERES NA CIÊNCIA: UM OLHAR PARA A PÓS-GRADUAÇÃO E A ÁREA DE MATERIAIS
RESUMOAs mulheres têm demonstrado intrínseca capacidade de liderança e, muitas vezes, são sub-representadas. A presença das mulheres na ciência pode ser ilustrada pelos dados do Prêmio Nobel. A proporção de laureadas mostra a intrínseca relação da realidade feminina e o reconhecimento da excelência de seus trabalhos científicos. No período de 1901-2019, 900 cientistas receberam o Prêmio Nobel e somente 53 eram mulheres. Muitos estudos têm mostrado o quadro mundial da participação de mulheres em diferentes profissões, incluindo as relacionadas à ciência. Nesse contexto, é evidente a crescente participação das mulheres no desenvolvimento do conhecimento científico e, em muitas áreas do conhecimento, são maioria e avançam para uma participação efetiva na carreira acadêmica. De toda forma, ainda se deparam com algumas barreiras, especialmente relacionadas à dupla jornada de trabalho, impactando na dedicação às suas carreiras.Palavras-chave: Materiais. Pós-graduação. Mulheres. ABSTRACT:Women have demonstrated intrinsic leadership skills and are often underrepresented. The presence of women in science can be illustrated by the Nobel Prize data. The proportion of laureates shows the relationship of the female reality and the recognition of the excellence of their scientific works. From 1901 to 2019, 900 scientists received the Nobel Prize and only 53 were women. Many studies have shown the global participation of women in different careers, including those related to science. Thus, the growing participation of women in the development of scientific knowledge is evident and, in many research areas, they are the majority and advanced towards effective participation in the academic career. Anyway, they still face some barriers, specially related to double working hours, impacting the dedication in their careers.Keywords: Graduate programs. Materials research area. Women
Portrait of an act: Aesthetics and ethics in The 'Portrait of a Lady' (Henry James)
Five tetrahydrofuran lignans and two known flavones were isolated from the aerial parts of Peperomia blanda. The structures of the isolated lignans were elucidated by interpretation of their spectroscopic data, including by gHMQC and gHMBC. The relative and absolute configurations of the isolates were determined from NOESY interactions and optical properties, respectively. Four of the lignans were diastercomeric whilst one was of mixed biosynthetic origin. All but one of the lignans exhibited high in vitro trypanocidal activity when assayed against epimastigotes of Trypanosoma cruzi strain Y. (C) 2007 Elsevier Ltd. All rights reserved
Flavones, lignans and terpene from Piper umbellata (Piperaceae)
The phytochemical investigation of Piper umbellata leaves yielded nine compounds including one terpenoid glucoside, five flavones (vitexin 2"-O-β-glucopyranoside, apigenin 8-C-β-D-glucopyranoside,orientin 8-C-β-D-glucopyranoside,5-hydroxy-7,3',4'-trimethoxy-flavone and velutin), two lignans (sesamin e dihydrocubebin) and 4-nerolidylcathecol. Excepting 4-nerolidylcathecol, all compounds have not been described from this species yet
CYP712K4 catalyzes the C-29 oxidation of friedelin in the Maytenus ilicifolia quinone methide triterpenoid biosynthesis pathway
The native Brazilian plant Maytenus ilicifolia accumulates a set of quinone methide triterpenoids with important pharmacological properties, of which maytenin, pristimerin and celastrol accumulate exclusively in the root bark of this medicinal plant. The first committed step in the quinone methide triterpenoid biosynthesis is the cyclization of 2,3-oxidosqualene to friedelin, catalyzed by the oxidosqualene cyclase friedelin synthase (FRS). In this study, we produced heterologous friedelin by the expression of M. ilicifolia FRS in Nicotiana benthamiana leaves and in a Saccharomyces cerevisiae strain engineered using CRISPR/Cas9. Furthermore, friedelin-producing N. benthamiana leaves and S. cerevisiae cells were used for the characterization of CYP712K4, a cytochrome P450 from M. ilicifolia that catalyzes the oxidation of friedelin at the C-29 position, leading to maytenoic acid, an intermediate of the quinone methide triterpenoid biosynthesis pathway. Maytenoic acid produced in N. benthamiana leaves was purified and its structure was confirmed using high-resolution mass spectrometry and nuclear magnetic resonance analysis. The three-step oxidation of friedelin to maytenoic acid by CYP712K4 can be considered as the second step of the quinone methide triterpenoid biosynthesis pathway, and may form the basis for further discovery of the pathway and heterologous production of friedelanes and ultimately quinone methide triterpenoids
HPLC-ElCD: an useful tool for the pursuit of novel analytical strategies for the detection of antioxidant secondary metabolites
Further monoterpene chromane esters from Peperomia obtusifolia: VCD determination of the absolute configuration of a new diastereomeric mixture
A reinvestigation of the monoterpene chromane ester enriched fraction from Peperomia obtusifolia using chiral chromatography led to the identification of a minor peak, which was elucidated by NMR and HRMS as fenchyl-3,4-dihydro-5- hydroxy-2,7-dimethyl-8-(3″-methyl-2″-butenyl)-2-(4′-methyl- 1′,3′-pentadienyl)-2H-1-benzopyran-6-carboxylate, the same structure assigned to two other fenchyl esters described previously, pointing out a stereoisomeric relationship among them. Further NMR analysis revealed that it was actually a mixture of two compounds, whose absolute configurations were determined by VCD measurements. Although, almost no vibrational transitions could be assigned to the chiral chromane, the experimental VCD spectrum was largely opposite to that obtained for the average experimental VCD [(2S,1‴R,2‴R,4‴S + 2R,1‴R,2‴R,4‴S)/2] for fenchol derivatives. These results allowed us to assign the putative compounds as a racemic mixture of the chiral chromane esterified with the monoterpene (1S,2S,4R)-fenchol, which had not been identified in our early work.Fil: Batista Junior, João Marcos. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Batista, Andrea N. L.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Kato, Massuo J.. Universidade de Sao Paulo; BrasilFil: Bolzani, Vanderlan S.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: López, Silvia Noelí. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Nafie, Laurence A.. Syracuse University; Estados UnidosFil: Furlan, Maysa. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi
Biosynthetic origins of the isoprene units of 4-nerolidylcatechol in Potomorphe umbellata
Decolourization of anthraquinone reactive dye by electrochemical reduction on reticulated glassy carbon electrode
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