Comparative time-course study of aminoacyl- and dipeptidyl-resin hydrolysis

The classic hydrolysis procedure for quantification of resin-bound aminoacyl and peptidyl groups with 12 N HCl: propionic acid was recvaluated by studying the influence of the nature of the resin and the resin-bound group. Their stability during acid hydrolysis was dependent on the C-terminal amino acid, and the order of acid stability was Phe > Val > Gly. Otherwise, the dipeptides Ala-Gly, Ala-Val, and Ala-Phe displayed enhanced rates of hydrolysis of the resin if compared with their parent aminoacyl groups. Amongthe resins assayed, the order of acid stability was: benzhydrylamine-resin > p-methylbenzhydrylamine-resin ≅4-(oxymethyl)-phenylacetamidomethyl-resin > chloromethyl-copolymer of styrene-1%-divinylbenzene. Important for peptide synthesis method, the findings demonstrate that longer hydrolysis times than previously recommended in the literature (1 h at 130°C and 15 min at 160°C for peptides attached to the chloromethyl-copolymer of styrene-1%-divinylbenzene) are necessary for the quantitative acid-catalyzed cleavage of some resin-bound groups. The observed broad range of hydrolysis time varied from less than 1 h to about 100 h.

Thermal Behavior and Spectroscopic Study of Neutral and Cationic Mononuclear Cyclopalladated Compounds

The reactions of the precursor [Pd(N,C-dmba)(MeCN)2](NO 3) (1) (dmba = N,N-dimethylbenzylamine), with the proligands 3,5-dimethylpyrazole (Hdmpz), 2-quinolinethiol (qnSH) and 1,1′- bis(diphenylphosphine)ferrocene (dppf) afforded the compounds [Pd(N,C-dmba)(Hdmpz)(ONO2)]0.5CH2Cl2 (2), [Pd(N,C-dmba)(qnSH)(ONO2)] 0.5CH2Cl2 (3) and [Pd(N,C-dmba)(dppf)](NO3) (4), respectively. The mononuclear species 2,3 and 4 were characterized by elemental analysis, infrared spectroscopy, NMR and thermogravimetric analysis. The IR spectra show bands which are consistent with terminal monodentate nitrate group for 2-3 and ionic nitrate for 4. The 1H and 13C NMR data confirm that coordination of the organic ligands has occurred and the 31P{1H} NMR data for 4 clearly evidences the occurrence in solution of three cyclopalladated species with the dppf acting as a bridging ligand in two cases and as a chelate in one. The thermal behavior of compounds 1-4 suggests that complex 2 is the most stable. The X-ray diffractometry results show the formation of PdO from 1 and 2, Pd2OSO4 from 3, and of a mixture of PdO and Fe 2(PO4)3 from 4, as final decomposition products.

Comparative study of MTA and other materials in retrofilling of pulpless dogs' teeth

This in vivo study compared the effect of mineral trioxide aggregate (MTA), IRM, Super EBA and ZOE in a puttylike consistency, used as retrofilling materials, in the healing process of periapical tissue of pulpless dogs' teeth submitted to a conventional retrofilling technique. Twenty-four premolars obtained from three dogs were used. At the first intervention, the animals were anesthetized, coronal access was obtained and pulpectomy was done. Root canals were kept open to the oral environment for 180 days to induce the formation of apical lesions. After surgical removal of the lesions with curettes, 2 mm of the apical root was cut out perpendicular to the long axis of the teeth, and root-end cavities were shaped with a low-speed round bur. The bone cavities were irrigated and dried, and the root-end cavities were filled with MTA, IRM, Super EBA and ZOE in a puttylike consistency. The bone cavities were passively filled with blood and flaps were sutured. The coronal access openings were cleaned and double-sealed with ZOE and amalgam. After 180 days, the animals were killed by anesthetic overdose, maxilla and mandible were removed and the pieces were processed for histomorphologic analysis. Data were evaluated blindly on the basis of several histopathologic events and the scores obtained were analyzed statistically using the Kruskal Wallis test. No significant differences were observed among MTA, Super EBA and IRM (p>0.05). However, ZOE had a significantly more negative influence on the apical healing (p<0.05). In conclusion, MTA, Super EBA and IRM had similar histopathologic effects among each other and better performance than ZOE used in a puttylike consistency. Furthermore, only MTA stimulated hard tissue deposition in direct contact with the retrofilling material, even when it was inserted under critical conditions.

Multiparticulate systems of pectin-chitosan: Study of swelling and drug release

The aim of this study was to prepare multiparticulate systems of pectin:chitosan (PC:CS) and to evaluate their swelling ratio and the drug release in different environments. PC:CS particles containing triamcinolone were prepared by a complex coacervation/ionotropic gelation method in aqueous environment. The polymer ratio, the calcium concentration and the contact time of the capsules with chitosan dispersion for particles formation and the structures obtained were analyzed. The systems were characterized in relation to morphology, size, swelling, and drug release behavior. The methodology used allowed the production of spherical particles with narrow range of size distribution. The entrapment efficiency for triamcinolone was 84.31 ± 439. It was observed that the particles present a relatively low swelling ratio in acidic medium and a larger swelling ratio in enteric medium. The release profile was dependent on pH and can be related with the swelling ratio.

A DFT Study of Structural and Electronic Properties of ZnS Polymorphs and its Pressure-Induced Phase Transitions

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Theoretical study of molecular and electronic structures of 5(1) knot systems: two-layered ONIOM calculations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Follow-up study of morphology and cardiac function in rats undergoing induction of supravalvular aortic stenosis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Three-year follow-up study of respiratory and systemic manifestations of chronic obstructive pulmonary disease

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alcoholic women and men: a comparative study of social and familial aspects and outcome

Objetivos: A proporção de ocorrência de alcoolismo em homens e mulheres tem uma variação de 14:1 até 2:1, mostrando a necessidade de estudos específicos para a população feminina. O objetivo deste estudo foi analisar o perfil e a evolução de alcoolistas, segundo gênero e gravidade da dependência. Métodos: Realizou-se um estudo longitudinal retrospectivo de 114 homens e 57 mulheres alcoolistas (CID-10), inscritos no ambulatório da Faculdade de Medicina de Botucatu, no período de 1990-1994 e avaliados até julho de 1997. Utilizou-se um questionário semi-estruturado, e, para avaliação da gravidade do alcoolismo, o Short Alcohol Dependence Data. Resultados/Conclusões: Os principais resultados mostraram que a estrutura familiar estava comprometida com: relacionamento difícil para 55,6% das mulheres e 65,7% dos homens; violência familiar em 74,1% das mulheres e 61,1% dos homens. As mulheres iniciaram a ingestão mais tarde que os homens (p=0,01), em geral com seus cônjuges (p=0,00). Não houve diferença de evolução no tratamento entre os gêneros. Os principais fatores associados à melhor resposta ao tratamento, independentemente do sexo, foram: nível de gravidade de dependência do álcool (dependentes leves e moderados apresentaram 5,59 vezes mais chances de melhorar do que os dependentes graves); ser praticante de alguma religião (2,3 vezes mais chances de melhora do que os pacientes que não eram praticantes); e tempo de seguimento no programa, negativamente correlacionado a chances de melhora (0,68 vezes menos chances de melhora que aqueles que permaneceram por tempo menor em tratamento).

A study of meiosis and spermiogenesis in the testicular lobes of Antiteuchus tripterus (Heteroptera : Pentatomidae)

An analysis of testicular morphology and spermatogenesis in the Heteroptera species Antileuchus tripterus (Pentatomidae) revealed that these traits differ from that recorded for other species of the same family. The testes of A. tripterus have only six lobes, while other species of the same family typically have seven lobes, including a compound lobe, i.e., a lobe containing another in its lumen. A study of meiosis and sperm structure in the different lobes of A. tripterus revealed a conventional meiosis in the lobes numbered one to three. In lobe four, however, prophase I spermatocytes exhibit the morphological characteristics of the so called diffuse stage and are larger than those in lobes 1-3 in this and the remaining phases of meiosis. Thus, the resulting spermatids are not only larger but also their head is morphologically different. Lobe 5 exhibits characteristies known from other Pentatomidae species such as an uneven distribution of chromatin to the daughter cells, which give rise to cells of different sizes. This lobe forms spermatozoa of different sizes. Lobe 6, contained within lobe 5, differs from it by having larger cells at a stage similar to the so called diffuse and spermatid tails with cross divisions, which are not found in other lobes and unreported in the literature.

A thermal analysis study of dithizone and dithizonates of mercury, silver and bismuth

Foram preparados os ditizonatos de Hg (I), Ag (I) e Bi (III). Termogravimetria (TG), termogravimetria derivada (DTG), calorimetria exploratória diferencial (DSC), difratometria de raios X pelo método do pó e análise elementar foram usados para caracterizar e para estudar a estabilidade térmica e a decomposição térmica da ditizona e destes ditizonatos.

Magnetic oxides of spinel structure: Study of CoxCuyMnzO4 and MgxNiyMnzO4 manganites (x+y+z=3)

Systematic studies in manganites of spinel structure have been undertaken. We report on the magnetic properties of two particular cases, in which one of the transition metals, Mg2+ is non-magnetic (NiMgxMn2-xO4) or presents a stable oxidation state, Cu2+ (CoxCuyMnzO4, x + y + z = 3). The magnetic behaviour is described with respect to varying contents of cobalt, copper or manganese. A ferrimagnetic transition is observed at 110-120 K, which depends on the cobalt content. Presence of copper increases the coercive field by a factor of ten with respect to the parent compound NiMn2O4. (c) 2006 Elsevier B.V. All rights reserved.

Small-angle X-ray scattering study of gelation and aging of Eu3+-doped sol-gel-derived siloxane-poly(oxyethylene) nanocomposites

The aggregation, gelation, and aging of urea-cross-linked siloxane-poly(oxyethylene) nanohybrids [(U600)-n] containing two different amounts of europium triflate initially dissolved in an ethanol-water mixture were investigated by in situ small-angle X-ray scattering (SAXS). For both low (n = [O]/[Eu] = 80) and high (n = 25) europium contents, the SAXS intensity was attributed to the formation of siloxane clusters of about 8-11 Angstrom in size. Siloxane cluster formation and growth is a rapid process in hybrids with low Eu contents and slow in Eu-rich hybrids. An additional contribution to the scattering intensity at very low angles was attributed to the formation of a coarse structure level. At this secondary level, the structure can be described as a set of dense domains containing siloxane clusters embedded in a depleted matrix composed of unfolded polymer chains and solvent. By fitting a theoretical function for this model to the experimental SAXS curves, relevant structural parameters were determined as functions of time during the sol-gel transition and gel aging. For hybrids with low europium contents (n = 80), the size of the siloxane clusters remains essentially invariant, whereas the dense segregation domains progressively grow. In hybrids with high doping contents (n = 25), the preponderant structure variation during the first stages of the sol-gel transformation is the slow growth of siloxane clusters. For these hybrids, the segregation of siloxane clusters forming dense domains occurs only during advanced stages of the process.