Oxorhenium(V) Complexes with 2,3-Dihydroxynaphthalene

2,3-Dihydroxynaphthalene (H(2)dhn) reacts with [ReOCl(3)-(PPh(3))(2)] or [ReOBr(3)(PPh(3))(2)] in a 1:1 molar ratio with formation of the isostructural complexes [ReOCl(2)(PPh(3))(2)(Hdhn)] (4) and [ReOBr(2)-(PPh(3))(2)(Hdhn)] (5). They have distorted octahedral coordination spheres with the halide and the triphenylphosphine ligands arranged in equatorial trans positions to each other. The Hdhn-ligand coordinates monodentately in trans position to the oxo ligand. Intramolecular hydrogen bonds between the Hdhn and the halogeno ligands stabilize this coordination mode. The products represent the first examples of oxorhenium(V) complexes with monodentate catecholate-type ligands.FAPESPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CAPES of BrazilCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Rhenium chelate complexes with maltolate or kojate

Novel rhenium complexes containing the maltolate (mal) or kojate (koj) anions as chelating ligands have been synthesized: [ReOCl(mal)(2)] (1), [ReOCl(2)(mal)(PPh(3))] (2), [ReOBr(2)(mal)(PPh(3))] (3), [ReOCl2(koj)(PPh(3))] (4) and [ReOBr(2)(koj)(PPh(3))] (5). The products have been characterized by MR, (1)H, (13)C, and (31)P NMR spectroscopies and elemental analysis. The crystal and molecular structures of all complexes were determined. Complex I crystallizes monoclinic, space group C2/c, Z = 8. It contains two O, O`-bidentate maltolate ligands and one chloro ligand at the (ReO)(3+) unit, so that a distorted octahedral geometry is adopted by the six-coordinated rhenium(V) center. The chloro ligand occupies a cis position to the oxo ligand. Complexes 2 and 3 are isostructural and crystallize orthorhombic, space group Pbca and Z = 8. The isostructural complexes 4 and 5 crystallize monoclinic, space group P2(1)/n and Z = 4. In complexes 2-5, the (ReO)(3+) unit is coordinated by a monoanionic O,O-bidentate unit of the maltolate (2 and 3) or kojate (41 and 5) ligand, one triphenylphosphine and two halogeno ligands (Cl in 2 and 4; Br in 3 and 5), with the rhenium(V) center in a distorted octahedral environment. The halide ligands are in cis positions to each other. (c) 2008 Elsevier Ltd. All rights reserved.CAPESCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FINEP[CT Infra 0970/01]Financiadora de Estudos e Projetos (FINEP

SÍNTESE E DETERMINAÇÃO DA ESTEREOQUÍMICA RELATIVA DE UM NOVO EPÓXIDO ALDEÍDO CICLOPENTANO MONOTERPENÓIDE

In this study, we report the preparation of a new tetra-substituted epoxide aldehyde cyclopentane, which acts as a starting material for the synthesis of plinol, from (R)-(+)-epoxy-limonene. The synthesis was performed in three steps and resulted in a good yield. The structural determination was performed by 1H and 13C NMR, and the relative stereochemistry was defined by nuclear Overhauser effect (NOE) experiments with computer calculations of molecular modeling, particularly with respect to indirect coupling constant calculations

Synthesis, characterization and biological analysis of the complex [VO(Hdhp)(2)] (H(2)dhp=2,3-dihydroxypyridine)

A new vanadium (IV) complex with the monoanion of 2,3-dihydroxypyridine (H(2)dhp), or 3-hydroxy-2(1H)-pyridone, was synthesized, characterized by physicochemical techniques and tested biologically. The EPR data for the [VO(Hdhp)(2)] complex in DMF are: g(x) = 1.9768, g(y) = 1.9768 and g(z) = 1.9390; A values (10(-4) cm(-1)): A(x), 59.4; A(y//), 59.4; A(z), 171.0. The vV=O band in the IR spectrum of the complex is at 986 cm(-1). The complex is paramagnetic, with mu(eff) = 1.65 BM (d(1), spin-only) at 25 degrees C. The irreversible oxidation process [V(V)/V(IV)] of the [VO(Hdhp)(2)] complex, as revealed in a cyclic voltammogram, occurs at 876 mV. The calculated molecular structure of [VO(Hdhp)(2)] shows the vanadium(IV) center in a distorted square pyramidal environment, with the oxo ligand in the apical position and the oxygen donor atoms of the Hdhp ligands in the basal positions. The ability of [VO(Hdhp)(2)] to mimic insulin, and its toxicity to hepato-biliary functions, were investigated in streptozotocin-induced diabetic rats and it was concluded that the length of treatment and the amount of [VO(Hdhp)(2)] administered were effective in reducing experimental diabetes

Growth inhibitory activity of a novel lectin from Cliona varians against K562 human erythroleukemia cells

Purpose in this study, the antitumoral potential of a novel lectin (CvL) purified from the marine sponge Cliona varians was studied in different cancer cell lines.Methods CvL cytotoxicity was evaluated in mammalian tumor cells and in normal human peripheral blood lymphocytes by the MTT assay using the same range of concentrations (1 - 150 mu g ml(-1)). the mechanisms involved in K562 cell death were investigated by confocal fluorescence microscopy, flow cytometry and immunoblot.Results CvL inhibited the growth of human leukemia cells, with IC(50) values of 70 and 100 mu g ml(-1) for K562 and JURKAT cells, respectively, but it was ineffective on blood lymphocytes and solid tumor cell lines. K562 cell death occurred 72 h after exposure to the lectin and with signs of apoptosis, as analyzed by DAPI and annexin V/PI staining. Investigation of the possible mediators of this process showed that cell death occurred via a caspase-independent pathway. Confocal fluorescence microscopy indicated a pivotal role for the lysosomal protease cathepsin B in mediating cell death. Accordingly, pre-incubation of K562 cells with the cathepsin inhibitor L-trans-epoxysuccinyl-L-leucylamido-(4-guanidino) butane (E-64) abolished CvL cytotoxic eVect. Furthermore, we found upregulation of tumor necrosis factor receptor 1 (TNFR1) and down-modulation of p65 subunit of nuclear factor kappa B ( NF kappa B) expression in CvL-treated cells. These effects were accompanied by increased levels of p21 and reduced expression of pRb, suggesting that CvL can induce cell cycle arrest.Conclusions Collectively, these findings indicate an anti-leukemic eVect for CvL and suggest that cathepsin B acts as a death mediator in CvL-induced cytotoxicity possibly in an uncharacterized connection with the membrane death receptor pathway.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Financiadora de Estudos e Projetos (FINEP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Dept Bioquim, BR-04044020 São Paulo, BrazilUniv Fed Rio Grande do Norte, Dept Biofis & Farmacol, Ctr Biociencias, BR-59072970 Natal, RN, BrazilUniv Estadual Campinas, Dept Bioquim, Inst Biol, BR-13083970 Campinas, SP, BrazilUniv Fed Rio Grande do Norte, Dept Bioquim, Lab Quim & Funcao Proteinas Bioativas, BR-59072970 Natal, RN, BrazilUniv Mogi das Cruzes, Ctr Interdisciplinar Invest Bioquim, BR-08701970 Mogi Das Cruzes, SP, BrazilUniv Fed Rio Grande do Norte, Dept Bioquim, Ctr Biociencias, BR-59072970 Natal, RN, BrazilUniversidade Federal de São Paulo, Dept Bioquim, BR-04044020 São Paulo, BrazilFAPESP: 06/07315-3Web of Scienc

A escrita de diários na formação docente The writing of diaries in teacher education

Este artigo buscou investigar as contribuições da escrita de diários para estudantes de um curso de Pedagogia que já haviam cursado as disciplinas de estágio supervisionado para a docência, em que uma das atividades se referia à elaboração de diários de campo. Os dados foram coletados por meio de questionários com perguntas abertas. A análise dos dados evidenciou que os alunos registravam os acontecimentos no diário logo após o estágio e realizavam uma descrição detalhada deles. Para a maioria dos estudantes a escrita dos diários possibilitou a reflexão sobre a prática observada e sobre a sua própria prática, configurou-se como um apoio à memória e possibilitou o distanciamento das experiências vividas, permitindo a análise mais densa destas. Além disso, evidenciou-se a importância de o formador oferecer feedbacks, orais ou escritos, e de a reflexão sobre os acontecimentos ser pautada no referencial teórico.<br>This article investigated the contribution that keeping a diary, made to pedagogy students who had already attended a course with a supervised teaching stage, in which one of the activities involved the development of field diaries. Data was collected from questionnaires with open questions. Data analysis showed that the students recorded the events in the diary shortly after the supervised lesson/teaching period and that they produced a detailed description of the facts/events. For most students, keeping a diary allowed them to reflect on the practice (of other students) they observed, and on their own practice, while also assisting their memory of events and permitting some detachment from their experiences, thereby allowing a more profound analysis of what took place. Moreover, it provided evidence of the importance of the supervisor offering feedback, written or oral, and also the importance of referring to theoretical literature while reflecting on one's teaching