182,824 research outputs found
6-Hydroxy-5,6-seco-stemocurtisine: a novel seco-stemocurtisine-type alkaloid
No full textA novel seco-stemocurtisine-type alkaloid, 6-hydroxy-5,6-seco-stemocurtisine was isolated from the aerial parts of Stemona curtisii (Stemonaceae) collected from Trang Province in Thailand. The unprecedented 5,6-seco-pyrido[1,2-a] azepine structure was elucidated by 2D NMR analysis and a single crystal X-ray crystallographic analysis. (C) 2013 Phytochemical Society of Europe
Banheiro seco: análise da eficiência de protótipos em funcionamento
No full textTCC(graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Biológicas. Biologia.O presente trabalho refere-se a duas etapas de pesquisas relacionadas ao sistema de saneamento denominado banheiro seco (ou sanitário compostável). A primeira etapa é referente ao projeto de edificação de um piloto de banheiro seco no campus da Universidade Federal de Santa Catarina – UFSC, denominado de “Banheiro seco: tecnologia limpa e de interesse social”. E a segunda se trata da pesquisa em três protótipos em funcionamento, um localizado no Município de Florianópolis e outros dois localizados no Município de Garopaba. Ambos os municípios se localizam no Estado de Santa Catarina, Brasil. O banheiro seco é uma tecnologia já consagrada em diversos países do mundo e, basicamente, utiliza o processo de compostagem para tratar e sanitarizar os dejetos humanos, reduzindo consideravelmente ou totalmente o uso de água para o transporte, armazenamento e tratamento destes resíduos. Para avaliar o protótipo criado pela equipe do projeto de construção de banheiro seco na UFSC fez-se uma comparação com os resultados obtidos na análise dos protótipos em funcionamento. Para estudar a eficiência dos protótipos em funcionamento foram realizados exames parasitológicos e análises de coliformes totais e fecais em amostras coletadas dos três protótipos. Foram desenvolvidos também estudos de avaliação da qualidade do ar, para identificar os gases produzidos durante a decomposição da matéria orgânica bem como testes para verificar a ocorrência ou não de maus odores. Por fim, foi feita uma análise química do composto final produzido pelo banheiro seco do Município de Florianópolis a fim de verificar a qualidade e aplicabilidade do mesmo como fertilizante orgânico. Concluiu-se que o sistema projetado pela equipe da UFSC apesar de alcançar parte de seus objetivos, apresenta alguns problemas, principalmente pela adoção da rampa de compostagem. Em relação aos protótipos estudados, observamos que o processo de compostagem nestes modelos não é eficiente. Quando o processo de compostagem não é eficiente, os patógenos não são exterminados, a convecção dos gases na câmara armazenadora não funciona (o que contribui para um refluxo do odor para o banheiro) e a decomposição da matéria se torna mais lenta. Sendo assim, os estudos mostram que o período de 6 meses estipulado pela literatura brasileira não é uma garantia de sanitarização do composto nem de realização do processo compostagem. Apesar disso, as análises químicas indicaram uma boa qualidade do composto produzido. Por fim, conclui-se com este trabalho que o processo de compostagem precisa ser muito bem desenvolvido e que existe uma grande dificuldade para alcançar as condições ideais necessárias para que este processo ocorra
Discovery of 9,11-Seco-Cholesterol Derivatives as Novel FXR Antagonists
No full textThe farnesoid X receptor
(FXR) plays an important role in the regulation
of bile acid, lipid, and glucose homeostasis. Recent findings have
shown that the inhibition of FXR is beneficial to improvement of related
metabolic diseases and cholestasis. In the present work, 9,11-seco-cholesterol
derivatives were designed and synthesized by cleaving the C ring of
cholesterol and were identified as novel structures of FXR antagonists.
Compound 9a displayed the best FXR antagonistic activity
at the cellular level (IC50 = 4.6 μM) and decreased
the expression of the target genes of FXR in vivo
Voucher funds in transitional economies : the Czech and Slovak experience
No full textVoucher funds have arisen in the transitional economies of Eastern and Central Europe that have used voucher privatization. These funds collect vouchers from citizens and use them to buy shares in enterprises. In the Czech and Slovak Republics, voucher funds are typically organized as corporations owned by the citizens who contributed their vouchers. Recently, they have also been organized as unit trusts (either open-ended or closed). A management company manages the funds under a contract that specifies the management fee. The management company is typically owned by the initial sponsor of the fund - for example, a bank. Voucher funds can give owners a diversified and professionally managed portfolio. More important, the funds select who sits on an enterprise's governance boards (which oversee management and profitability). Although experience is limited, the funds in these two countries have probably stopped most fraud and self-serving by enterprise mangers and are beginning to encourage the restructuring needed for profitability. A few funds have replaced poorly performing or dishonest managers; more often, because qualified replacements are few, they encourage managers to improve performance. There have been complaints about funds'performance. Some have made unrealistic promises to voucher holders and have appointed poorly qualified members to management boards. There is concern about conflicts of interest in the bank-sponsored funds and excessive control of enterprises. Funds typically lack capital or expertise to undertake restructuring - but few other potential owners are likely to be better qualified. The author examines 27 regulations that have been proposed for funds. Regulations in transitional economies, unlike regulations in most western countries, should encourage funds to play a strong role in corporate governance, he contends, as few potential owners have this ability. Most important, regulations should require that funds disclose information about their operations so their owners can monitor and control fund managers. The regulatory regime, the author says, should discourage monopolies and anticompetitive behavior; create incentives for fund managers to improve fund performance; discourage self-serving or fraudulent behavior by fund managers, and conflicts of interest; and eliminate high-risk investments unacceptable to fund owners. Because there is so little experience with these funds, the regulatory regime should not be unduly restrictive. As problems arise, regulations to deal with them can be added.International Terrorism&Counterterrorism,Economic Adjustment and Lending,Economic Theory&Research,Agricultural Knowledge&Information Systems,Payment Systems&Infrastructure
New 3,4<i>-seco-</i>diterpene and coumarin derivative from the leaves of <i>Trigonostemon flavidus</i> Gagnep
No full textTwo new compounds named trigoflavidus A (1) and trigoflavidus B (2), and eight known compounds, trigoflavidone (3), heterophypene (4), howpene C (5), 3,4-seco-sonderianol (6), trigonochinene C (7), fraxidin (8), isofraxidin (9), and isofraxetin (10) were isolated from the leaves of Trigonostemon flavidus Gagnep. by various chromatographic methods. Their chemical structures were elucidated via UV, IR, HR-ESI-MS and NMR spectroscopic methods and divided into two groups including six 3,4-seco-diterpenes (1, 3-7) and four coumarins (2, 8-10). Absolute configurations at stereocenters of compound 1 were confirmed by comparison of its CD spectra with those of the TD-DFT calculations. At a concentration of 30 µM, compounds 1–10 exhibited weak cytotoxic activity toward LU1, HepG2, MCF7, and SKMel2 human cell lines (cell viability all over 50%).</p
Enantiospecific synthesis of B-seco-C-aromatic taxanes
No full textA simple and efficient methodology for the enantiospecific synthesis of B-seco-C-aromatic taxanes starting from monoterpene (R)-carvone is described. Coupling of 6,6-dimethylcarvone 5 with appropriate arylethyl bromides followed by oxidation generates the enones 7, 15, 25, which are transformed into the 20-nor-B-seco-C-aromatic taxane derivatives 11, 17 and B-seco-C-aromatic taxane derivative 29 via degradation of the isopropenyl group
Enantiospecific synthesis of B-seco-C-aromatic taxanes<sup>†</sup>
No full text905-914A simple and efficient
methodology for the enantiospecific synthesis of B-seco-C-aromatic taxanes
starting from monoterpene (R)-carvone is described. Coupling of
6,6-dimethylcarvone 5 with appropriate arylethyl bromides followed by oxidation
generates the enones 7, 15, 25, which are transformed into the
20-nor-B-seco-C-aromatic taxane derivatives 11, 17 and 8-seco-C-aromatic
taxane derivative 29 via degradation of the isopropenyl group
Synthesis, biology, and modeling of a C-4 carbonyl C,D-seco-taxoid
No full textA C,D-seco-paclitaxel derivative 26 was prepared from taxine and tested for biological activity. Chemical reactivity of the seco-compounds proved to be substantially modified, with respects to taxoids. The corresponding C,D-seco-taxoid does not show tubulin stabilizing activity or cytotoxicity. Explanation of these observations based on molecular modeling is provided. (c) 2006 Elsevier Ltd. All rights reserved
Sculponins A-C, three new 6,7-seco-ent-kauranoids from Isodon sculponeatus
No full textThree new 6,7-seco-eni-kauranoids (1-3) were isolated and structures were elucidated from Isodon sculponeatus. Diterpenoids 1-3 possessing multicyclic skeletons formed via oxygen atoms are all unprecedented among ent-kauranes. Compound I displayed significant cytotoxic activity against K562, A549, and HepG2 human tumor cell lines, with IC50 values of 1.4, 2.3, and 2.0 mu M, respectively, equal to the positive control. Plausible pathways for the biosynthesis of I and 2 from one related diterpenoid were also postulated. (C) 2007 Elsevier Ltd. All rights reserved
Olho seco: inovações em olho seco
No full textApresentam-se as características, classificação e tratamento do olho seco. Apresenta-se igualmente a suplementação alimentar como nova possibilidade no tratamento de olho seco
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