Síntese e caracterização de alfa-fosfato de zircônio(IV) contendo agregados de cobre metálico

The alpha-zirconium (IV) hydrogenphosphate (alpha-ZrP) has received great attention in the last years due to its properties like ion exchange, intercalation, ionic conductivity and catalytic activity. This work reports a method to produce metallic copper clusters on alpha-ZrP to be used as catalysts in petrochemical processes. It was found that the solids were non-crystalline regardless of the uptake of copper and the reduction. The specific surface area increased as a consequence of the increase of the interlayer distance to accept the copper ions between the layers. During the reduction, big clusters of copper (0,5-11µ) with different sizes and shapes were produced.

Bioquímica e ação citotóxica de alfa-aminocetonas endógenas

alpha-Aminoketones are expected to undergo enolization and subsequent aerobic oxidation yielding oxyradicals and highly toxic a-oxoaldehydes. Our interest has been focused on two endogenous a-aminoketones: 5-aminolevulinic acid (ALA) and aminoacetone (AA), accumulated in porphyrias and diabetes mellitus, respectively, and recently implicated as contributing sources of oxyradicals in these diseases. The final oxidation product of ALA, 4,5-dioxovaleric acid (DOVA), is able to alkylate DNA guanine moieties and expected to promote protein cross-linking. Methylglyoxal (MG), the final oxidation product of AA, is also highly cytotoxic and able to aggregate protein molecules. This review covers chemical and biochemical aspects of these alpha-aminoketones and their putative roles in the oxidative stress associated with porphyric disorders and diabetes.

Fotoquímica de alfa,alfa-dimetilvalerofenona adsorvida em celulose microcristalina

Irradiation of a,a-dimethylvalerophenone (1) adsorbed on microcrystalline cellulose employing methanol as the solvent shows a Norrish Type II/Type I ratio of 1.0±0.1. In solution, values of 2.3±0.3 in benzene and 8.7±2.0 in terc-butanol were obtained. The cyclization/elimination ratio for the Norrish Type II reaction of 1 shows values of 1.2±0.3 in cellulose, 17.9±2.7 in benzene and 3.2±03 in terc-butanol. When samples of 1/microcrystalline cellulose were prepared employing n-hexane, the Type II/Type I (29.5±2.9) and the cycl/elim (113.3±12.1) ratios were dramatically modified. These results demonstrate the difference in the behavior of 1 when entrapped in the cellulose chains or adsorbed on the cellulose surface.

alfa e b-glucosidases como alvos moleculares para desenvolvimento de fármacos

Glucosidases are involved in key steps in the processing of oligosaccharides by cleaving O-glucose residues. Since they catalyze breaking and transfer reactions of glucosidic groups for the normal growth and development of all the cells, defects or genetic deficiencies in these enzymes are associated with serious disorders of the carbohydrate metabolism. Thus, glucosidases represent important targets to develop inhibitors, owing to their potential activities against viruses, tumoral growth and metastasis, diabetes, Gaucher's disease and other syndromes associated with the lisosomal storage of glucoesphingolipids, and osteoarthritis. This paper presents a description of the biochemical pathways and mechanisms of alpha and beta-glucosidases, and the currently available drugs capable to inhibit these enzymes.

Uma nova síntese de alfa-bromo-acetofenonas e sua aplicação na obtenção de 2-benzoil-benzofuranas

alpha-Bromoacetophenones are important in organic synthesis. They have been widely used as precursors of several natural products. Several methods of bromination aiming at their synthesis have been described, however they furnish a mixture of starting material 10, mono 8 and dibromide 11 products. We developed a novel, simple and efficient synthesis of these compounds with applications in the synthesis of benzoylbenzofurans 9, compounds with important pharmacological properties, such as the ability of dilating the coronary artery and analgesic action. Such compounds have also been used as key intermediates to obtain quinone systems.

Quantification of the bond-angle dispersion by Raman spectroscopy and the strain energy of amorphous silicon

A thorough critical analysis of the theoretical relationships between the bond-angle dispersion in a-Si, Δθ, and the width of the transverse optical Raman peak, Γ, is presented. It is shown that the discrepancies between them are drastically reduced when unified definitions for Δθ and Γ are used. This reduced dispersion in the predicted values of Δθ together with the broad agreement with the scarce direct determinations of Δθ is then used to analyze the strain energy in partially relaxed pure a-Si. It is concluded that defect annihilation does not contribute appreciably to the reduction of the a-Si energy during structural relaxation. In contrast, it can account for half of the crystallization energy, which can be as low as 7 kJ/mol in defect-free a-Si

Extração, estruturas e propriedades de alfa- e beta-quitina

The fact that alpha- and beta-chitin adopt different arrays in the solid state is explored to emphasize their different properties and distinct spectral characteristics and X ray diffraction patterns. The methods for their extraction from the biomass in view of the preservation of their native structures and aiming to fulfill the claims of purity and uniformity for potential applications are discussed. The different arrays adopted by alpha- and beta-chitin also result in distinct reactivities toward the deacetylation reaction. Thus, the deacetylation of beta-chitin is more efficient owing to the better accessibility to amide groups due to the lower crystallinity of this polymorph.

Perfil químico de cultivares de feijão (phaseolus vulgaris) pela técnica de high resolution magic angle spinning (HR-MAS)

The application of one-dimensional proton high-resolution magic angle spinning (¹H HR-MAS) NMR combined with a typical advantages of solid and liquid-state NMR techniques was used as input variables for the multivariate statistical analysis. In this paper, different cultivars of beans (Phaseolus vulgaris) developed and in development by Embrapa - Arroz e Feijão were analyzed by ¹H HR-MAS, which have been demonstrated to be a valuable tool in its differentiation according chemical composition and avoid the manipulation of the samples as used in other techniques.

Adsorção de alfa-lactalbumina do soro de leite em hidroxiapatita: efeito do pH e da temperatura e análise termodinâmica

The nutritional and functional benefits offered by whey protein α-lactalbumin justify the great interest in its manufacture in large quantities at a high purity level. Hydroxyapatite is a calcium phosphate material able to adsorb proteins and can be synthesized at low production cost. Therefore, this work evaluated the adsorption of α-lactalbumin on hydroxyapatite using solid-liquid phase equilibrium data reported as adsorption isotherms. Van't Hoff's thermodynamics analysis showed that the adsorption process is entropically driven.

Electron transfer by singlet excited state of porphyn and electron acceptor affinity in rigid medium: photoacoustic phase angle analysis

Photoacoustic spectroscopy provides information about both amplitude and phase of the response of a system to an optical excitation process. This paper presents the studies of the phase in the electron transfer process between octaethylporphyn (OEP) and quinone molecules dispersed in a polymeric matrix. It was observed a tendency in the phase behavior to small values only in the spectral region near to 620 nm, while for shorter wavelength did not show any tendency. These measurements suggested that the electron transfer to acceptor occurred with the participation of octaethylporphyn singlet excited state.

Purificação e caracterização de alfa-galactosidases de sementes de Platymiscium pubescens Micheli

Este trabalho objetivou foi determinar a composição bioquímica de sementes de espécies florestais e caracterizar a enzima alfa-galactosidase de sementes germinadas de Platymiscium pubescens. Os maiores teores de lipídios foram determinados em sementes de Chorisia speciosa, Caesalpinia peltophoroides, Tabebuia serratifolia e Tabebuia velanedae, enquanto sementes de Enterolobium contortisiliquum, Schizolobium parahyba e Cassia grandis apresentaram os maiores teores protéicos. A alfa-galactosidase catalisa a hidrólise dos oligossacarídeos de rafinose, em sementes de leguminosas, durante a germinação. A maior atividade da alfa-galactosidase foi detectada em sementes de Platymiscium pubescens após 72 h de embebição. Duas formas de alfa-galactosidases, C1 e C2, foram purificadas de sementes germinadas de P. pubescens, usando-se fracionamento com sulfato de amônio e cromatografias de filtração em gel e de afinidade. Essas enzimas apresentaram atividade máxima em pH 5,5 e a 50-55 ºC. Os valores de Km ap das formas C1 e C2, para o substrato ro-nitrofenil-alfa-D-galactopiranosídeo, foram de 0,54 mM e 0,78 mM, e para a rafinose, de 4,64 mM e 5,09 mM, respectivamente. Essas enzimas exibiram estabilidade térmica moderada, mantendo 70% da atividade original após 3 h de incubação a 45 ºC. A atividade enzimática da C1 e C2 foi totalmente perdida na presença de CuSO4 e dodecil sulfato de sódio (SDS). Tais enzimas também hidrolisaram melibiose, rafinose e estaquiose, indicando potencial para aplicações biotecnológicas.

VARIATION OF MICROFIBRIL ANGLE OF Pinus radiata D. Don IN RELATION TO TREE SPACING IN CHILEAN PLANTATIONS

ABSTRACTFour stands of 28-year-old radiata pine (Pinus radiata D. Don) grown in the eighth region (Biobio) of Chile were sampled to determine the effect of tree spacing on the microfibril angle. The samples were taken at two different stem levels of the tree, 2.5 m and 7.5 m, with increment strip taken in the Nothern direction. The four experimental stands were characterized by the following spacing 2x2, 2x3, 3x4 and 4x4. The microfibril angle was measured by X-ray diffraction with the SilviScan technology at the FP-Innovation-Paprican Division in Vancouver, Canada. The results showed a significant effect of tree spacing on the microfibril angle in both juvenile wood and mature wood as well as at the two stem levels considered. The minimum (9.42º) was reached in 2x2 stand at 7.5 m in mature wood, while maximum microfibril angle (24.54º) was obtained in 2x3 stand at 2.5 m in juvenile wood. Regarding the effect of tree spacing, 4x4 stand had the lowest microfibril angle,except in mature wood at 7.5 m where 4x4 had the highest microfibril angle (11°) of the four stands.

Distribution pattern, surface tension and contact angle of herbicides associated to adjuvants on spraying and control of Ipomoea hederifolia under rainfall incidence

ABSTRACTScarlet Morning Glory is considered to be an infesting weed that affects several crops and causes serious damage. The application of chemical herbicides, which is the primary control method, requires a broad knowledge of the various characteristics of the solution and application technology for a more efficient phytosanitary treatment. Therefore this study aimed to characterize the effect of rainfall incidence on the control of Ipomoea hederifolia, considering droplet size, surface tension, contact angle of droplets formed by herbicides liquid on vegetal and artificial surfaces, associated to adjuvants and the volumetric distribution profile of the spray jet. The addition of the adjuvants to the herbicide spraying liquid improved the application quality, as it influenced the angle formed by the spray by broadening the deposition band of the spray nozzle and thus the possible distance between the nozzles on spray boom and due the changes at droplet size, which contribute to a safety application. The rainfall occurrence affected negatively the weed control with the different spraying liquids and also the dry matter weight, suggesting that the phytosanitary product applied was washed off.

Esquitossomose mansônica hepatoesplênica humana: produção de TNF-alfa em monócitos

OBJETIVO: Investigar os níveis de liberação de TNF-alfa?em cultura de monócitos em portadores humanos da forma hepatoesplênica de esquistossomose mansônica. MÉTODO: Foram incluídos aleatoriamente, no estudo, 39 voluntários de idades variando entre 15 e 31 anos, 19 homens e 20 mulheres, divididos em três grupos. Grupo 1 (GC) 12 indivíduos sadios, sem esquistossomose. Grupo 2 (AI) 18 indivíduos portadores de esquistossomose mansônica na forma hepatoesplênica, que tinham se submetido a esplenectomia, ligadura da veia gástrica esquerda e auto-implante de tecido esplênico no omento maior, quando tinham idades entre 7 e 16 anos. Esses pacientes receberam oxaminiquine na dose de 20mg/kg 30 dias antes do procedimento cirúrgico. O seguimento médio atual é de cerca de 8 anos. Grupo 3 - pacientes esplenectomizados sem auto-implante esplênico (ESAI) constituído de nove adultos jovens que tinham se submetido à esplenectomia sem auto-implante esplênico e desconexão ázigo-porta. Os pacientes esquistossomóticos dos grupos 2 e 3 tiveram confirmação dessa doença pela presença de fibrose de Symmers nas biópsias hepáticas realizadas durante o ato cirúrgico. Foram colhidos 6 ml de sangue periférico de cada um dos voluntários incluídos no presente estudo, cujos monócitos foram separados por centrifugação e cultivados no meio de cultura CultilabÒ). Amostras de 100ml do sobrenadante da cultura de monócitos (10(6) células/ml), de cada indivíduo dos três grupos, eram colhidos para determinação das concentrações de TNF-alfa. Essa concentração era mensurada pelo estudo colorimétrico de ELISA para citocinas (QuanticininasTM - Sistema R&D), após 4 horas de estimulação com PMA e incubação, em uma atmosfera úmida com 5% de CO² a 37ºC. RESULTADOS: As concentrações de TNF-alfa? não diferiram significantemente nos três grupos estudados [(GC 135,0 ± 51,6 pg/ml; AI 97,0 ± 25,4 pg/ml e ESAI 107,0 ±. 52,1 pg/ml) - ANOVA, F = 0,210; p = 0,813]. CONCLUSÃO: Os achados contribuem para hipótese de que após esplenectomia com ou sem auto-implante esplênico a função dos monócitos, com relação a produção de TNF-alfa, mantém-se preservada.

Associação entre os polimorfismos HaeIII e MspI do gene para o receptor alfa de estrogênio e densidade mamográfica em mulheres após a menopausa

OBJETIVO: Avaliar a presença dos polimorfismos HaeIII e MspI do gene para o receptor de estrogênio alfa, bem como fatores clínicos e suas possíveis associações com a densidade mamográfica em mulheres após a menopausa. MÉTODOS: Foram avaliadas 115 mulheres após a menopausa, não usuárias de terapia hormonal e sem lesão mamária clínica ou mamograficamente identificada. A densidade mamográfica foi determinada por três observadores independentes, tomando-se como base a classificação dos padrões mamográficos do ACR-BIRADS®, 2003 (duas avaliações subjetivas e uma computadorizada - Adobe Photoshop® 7.0). Amostras de raspado bucal foram obtidas para extração de DNA e em seguida foi realizada uma PCR-RFLP (Polymerase Chain Reation - Restriction Fragment Length Polymorphism) para análise de polimorfismos presentes no íntron 1 e éxon 1 do gene do REalfa (HaeIII e MspI). RESULTADOS: O polimorfismo HaeIII foi encontrado em 43 (37,4%) das 115 mulheres, ao passo que o MspI estava presente em 96 (83,5%) das mesmas. Houve alto grau de concordância entre os três observadores na determinação da densidade mamográfica. Trinta e quatro (29,6%) mulheres tinham mamas densas, e 81 (70,4%), mamas lipossubstituídas. CONCLUSÃO: Não houve associação entre o polimorfismo HaeIII do gene para o receptor de estrogênio alfa e densidade mamográfica (Fisher = 0,712). Houve associação próxima à significância estatística entre o polimorfismo MspI e densidade (Fisher = 0,098). Idade, paridade e índice de massa corporal mostraram-se associados com densidade mamográfica.