Use of sugarcane bagasse and grass hydrolysates as carbon sources for xylanase production by Bacillus circulans D1 in submerged fermentation

The use of sugarcane bagasse and grass as low cost raw material for xylanase production by Bacillus circulans D1 in submerged fermentation was investigated. The microorganism was cultivated in a mineral medium containing hydrolysate of bagasse or grass as carbon source. High production of enzyme was obtained during growth in media with bagasse hydrolysates (8.4 U/mL) and in media with grass hydrolysates (7.5 U/mL). Xylanase production in media with hydrolysates was very close to that obtained in xylan containing media (7.0 U/ mL) and this fact confirm the feasibility of using this agro-industrial byproducts by B. circulans D1 as an alternative to save costs on the enzyme production process. (c) 2005 Elsevier Ltd. All rights reserved.

Identification of a new quaternary association for legume lectins

Lotus tetragonolobus lectin (LTA) is a fucose-specific legume lectin. Although several studies report a diverse combination of biological activities for LTA, little is known about the mechanisms involved in L-fucosyl oligosaccharide recognition. The crystal structure of LTA at 2.0 angstrom resolution reveals a different legume lectin tetramer. Its structure consists of a homotetramer composed of two back-to-back GS4-like dimers arranged in a new mode, resulting in a novel tetramer. The LTA N-linked carbohydrate at Asn4 and the unusual LTA dimer-dimer interaction are related to its particular mode of tetramerization. In addition, we used small angle X-ray scattering to investigate the quaternary structure of LTA in solution and to compare it to the crystalline structure. Although the crystal structure of LTA has revealed a conserved metal-binding site, its L-fucose-binding site presents some punctual differences. Our investigation of the new tetramer of LTA and its fucose-binding site is essential for further studies related to cross-linking between LTA and complex divalent L-fucosyl carbohydrates. (C) 2007 Elsevier B.V. All rights reserved.

Surgical treatment of squamous cell carcinoma of tongue with carbon dioxide laser radiation (CO2)

In this clinical study, we proposed to observe the efficacy of the treatment of squamous cell carcinoma of the tongue (SCCT) by carbon dioxide (CO2) laser surgery. Twelve patients with SCCT were treated with excisional surgery using the CO2 laser with a spot size of 0.8 mm, 10 W, power density of 2.5 W/cm(2) in continuous mode, and under constant vacuum removal of the plume. The post surgical clinical evaluations were done every day until the sutures were removed and then every 7 days up to 1 month postoperatively. Subjects were re-examined quarterly until the fifth year post surgery. After 5 yr of follow-up for all subjects, there was no recurrence of the SCCT at the involved sites. The functional and aesthetic results observed were excellent. It is concluded that CO2 laser ablation of SCCT is an extremely useful surgical technique that can provide a clean field and is capable of providing surgical results consistent with accepted principles of oncological surgery. (C) 2012 Laser Institute of America.

Effect of the surface treatment of plain carbon fiber posts on the retention of the composite core: an in vitro evaluation

Foi avaliado o possível efeito de tratamentos superficiais em pinos de fibra de carbono lisos, quando comparados aos pinos serrilhados, na retenção à resina composta empregada na confecção de núcleos de preenchimento. Foram utilizados cinqüenta pinos de fibra de carbono, divididos em cinco grupos: os quatro primeiros grupos eram constituídos por pinos do tipo liso, cujas superfícies foram tratadas, e o último grupo por dez pinos do tipo serrilhado. Foram desenvolvidas matrizes de resina acrílica com um leito ajustado para conter o pino, com um alargamento na porção coronária para posterior preenchimento com resina composta. Após o tratamento superficial, todos os pinos receberam camadas de primer, foram secos e então ajustados à matriz de resina, colocando-se a resina composta autopolimerizável na porção coronária para um núcleo de preenchimento de 3 mm. As amostras foram submetidas a termociclagem e armazenadas em água destilada por uma semana. Os espécimes foram testados por meio de ensaios mecânicos de tração, à velocidade de 0,5 mm/min, até o deslocamento do conjunto ou a fratura da resina do núcleo. As conclusões foram as seguintes: a) o tratamento superficial nos grupos tratados por meio de jateamento (Grupo A), pontas diamantadas marcadoras de profundidade para facetas laminadas (Grupo C) e alteração da morfologia da extremidade coronária (Grupo D) conferiu aos pinos lisos valores de retenção comparáveis aos dos pinos serrilhados (Grupo E) nos ensaios de tração, porém sem diferença estatisticamente significativa entre estes grupos; b) os pinos tratados por meio de pontas diamantadas de granulação média (Grupo B) obtiveram valores de retenção menores que os demais grupos.

Fracture resistance of endodontically treated teeth with different heights of crown ferrule restored with prefabricated carbon fiber post and composite resin core by intermittent loading

This study evaluated the fracture resistance of endodontically treated teeth restored with prefabricated carbon fiber posts and varying quantities of coronal dentin. Sixty freshly extracted upper canines were randomly divided into groups of 10 teeth each. The specimens were exposed to 250,000 cycles in a controlled chewing simulator. All intact specimens were subjected to a static load (N) in a universal testing machine at 45 degrees to the long axis. Data were analyzed by 1-way analysis of variance and Tukey test (alpha = .05). Significant differences (P < .001) were found among the mean fracture forces of the test groups (positive control, 0 mm, 1 mm, 2 mm, 3 mm, and negative control groups: 1022.82 N, 1008.22 N, 1292.52 N, 1289.19 N, 1255.38 N, and 1582.11, respectively). These results suggested that the amount of coronal dentin did not significantly increase the fracture resistance of endodontically treated teeth restored with prefabricated carbon fiber post and composite resin core. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;106:e52-e57)

EXOTIC CARBON SYSTEMS IN TWO-NEUTRON HALO THREE-BODY MODELS

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

Quaternary of the Pantanal, west-central Brazil

The Pantanal is a tectonic depression located at the left margin of the Upper Paraguay River. The Paraguay is the trunk river of an alluvial depositional tract composed by several large marginal alluvial fans, the Taquari fan being the largest one. The present landscape is a complex tropical wetland characterized by month-long floods every year, with geomorphic features derived from the present conditions and others inherited from successive Pleistocene and Holocene climates. Some areas containing ponds are landscape relicts generated by eolian deflation during the Last Glacial Maximum. Many ponds, closed depressions isolated from the superficial waters by vegetated crescent ridges of fine sands, were interpreted as salt pans bordered by lunette sand dunes. Initiation of the modern wetland has occurred during the Pleistocene/Holocene transition, with the change to a more humid climate and the individualization of lacustrine systems. Active tectonics has been playing an important role in the development of the Pantanal landscape. Nowadays, the Paraguay River meanders in a large flood plain with extensive swamp surfaces, being structurally constrained by faults in the west border of the basin. Sedimentation within the Pantanal wetland is also affected by tectonic activity, especially along faults associated with the Transbrasiliano Lineament. (C) 2003 Elsevier B.V. Ltd and INQUA. All rights reserved.

Effect of citrate ions on the electrochemical behaviour of low-carbon steel in borate buffer solutions

The electrochemical behaviour of cold-rolled low carbon steel was studied on both active and passive potential regions in borate buffer solutions with and without the addition of sodium citrate (NaCit). In the active region anodic charges increased significantly and RCT values decreased with citrate, due to the formation of soluble complexes. In the passive potential region the film formed at +0.4 V in borate buffer solution with and without 0.010 M NaCit is probably enriched by Fe3O4 oxide, while films formed at +0.8 V are probably enriched by gamma-Fe2O3. The equivalent circuit [R-s(R(CT)Q)] fitted all experimental impedance data. (C) 2003 Elsevier Ltd. All rights reserved.

Alloys and oxides on carbon-supported Pt-Sn electrocatalysts for ethanol oxidation

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

Poly(glutamic acid) nanofibre modified glassy carbon electrode: Characterization by atomic force microscopy, voltammetry and electrochemical impedance

Glassy carbon electrodes (GCE) were modified with poly(glutamic acid) acid films prepared using three different procedures: glutamic acid monomer electropolymerization (MONO), evaporation of poly(glutamic acid) (PAG) and evaporation of a mixture of poly(glutamic acid)/glutaraldehyde (PAG/GLU). All three films showed good adherence to the electrode surface. The performance of the modified GCE was investigated by cyclic voltammetry and differential pulse voltammetry, and the films were characterized by atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The three poly(glutamic acid) modified GCEs were tested using the electrochemical oxidation of ascorbic acid and a decrease of the overpotential and the improvement of the oxidation peak current was observed. The PAG modified electrode surfaces gave the best results. AFM morphological images showed a polymeric network film formed by well-defined nanofibres that may undergo extensive swelling in solution, allowing an easier electron transfer and higher oxidation peaks. (C) 2007 Elsevier Ltd. All rights reserved.

Electrochemical behavior of a glassy-carbon electrode chemically modified with cadmium pentacyanonitrosylferrate in the presence of tetrahydrothiophene

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

Electrooxidation of sulfide by cobalt pentacyanonitrosylferrate film on glassy carbon electrode by cyclic voltammetry

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

Determination of isoniazid in human urine using screen-printed carbon electrode modified with poly-L-histidine

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

Dissolved organic carbon in rainwater from areas heavily impacted by sugar cane burning

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

Electrochemical reduction of nitroprusside on a glassy carbon electrode modified by poly-L-lysine films

The present work describes the preparation and characterization of polyelectrolyte coatings of poly-L-lysine (PLL) to modify a glassy carbon electrode and its application to the pre-accumulation of nitroprusside (NP). The effects of the coating on the electrochemical reduction of NP were investigated. The performance of the modified electrode indicates that the drug can be immobilized by electrostatic interaction and the voltammetric signal monitored at all pH values in the range of 2-12. The strong interaction between NP and PLL stabilizes the complex on the electrode surface and minimizes the chemical reaction of lost CN- ions as a subsequent reaction of electron transfer, which could improve the action mechanism of NP.