Heterogeneous photocatalytic treatment of organic dyes in air and aqueous media

This review focuses on the heterogeneous photocatalytic treatment of organic dyes in air and water. Representative studies spanning approximately three decades are included in this review. These studies have mostly used titanium dioxide (TiO2) as the inorganic semiconductor photocatalyst of choice for decolorizing and decomposing the organic dye to mineralized products. Other semiconductors such as ZnO, CdS, WO3, and Fe2O3 have also been used, albeit to a much smaller extent. The topics covered include historical aspects, dark adsorption of the dye on the semiconductor surface and its role in the subsequent photoreaction, semiconductor preparation details, photoreactor configurations, photooxidation kinetics/mechanisms and comparison with other Advanced Oxidation Processes (e.g., UV/H2O2, ozonation, UV/O3, Fenton and photo-Fenton reactions), visible light-induced dye decomposition by sensitization mechanism, reaction intermediates and toxicity issues, and real-world process scenarios. © 2008 Elsevier B.V. All rights reserved.

Treatment of experimental periodontal disease by a selective inhibitor of cyclooxygenase-2 with scaling and root planing (SRP)

Lumiracoxib is a selective inhibitor of cyclooxygenase-2 (COX-2) approved for the relief of symptoms of chronic inflammatory conditions. The aim of this study was to evaluate the effects of this specific inhibitor of COX-2 as adjunctive treatment on induced periodontitis in rats. Periodontal disease was induced at the first mandibular molar of 60 rats. After 7 days, the ligature was removed and all animals were submitted to scaling and root planing (SRP) along with local irrigation with saline solution and were divided into 2 groups: SRP (n = 30)-received subcutaneous injections of 1 mg/kg of body weight/day of saline solution for 3 days and; SRP + L (n = 30)-received subcutaneous injections of 1 mg/kg of body weight/day of Lumiracoxib for 3 days. Ten animals in each group were killed at 7, 15, and 30 days. The histological description was performed and the histometric values were statistically analyzed. In Group SRP + L, the histometric analysis (0.58 ± 0.08, 0.64 ± 0.06, and 0.56 ± 0.10 mm 2) showed less bone loss (p < 0.05) than Group SRP (1.52 ± 0.08, 1.55 ± 0.09, and 1.49 ± 0.24 mm 2) at 7, 15, and 30 days, respectively. Within the limits of this study it can be concluded that subcutaneous application of specific inhibitor of COX-2 was a beneficial adjunctive treatment for periodontal diseases induced in rats. © 2010 Springer Basel AG.

Influence of specimen size, tray inclination and air flow rate on the emission of gases from biomass combustion

Experiments of biomass combustion were performed to determine whether specimen size, tray inclination, or combustion air flow rate was the factor that most affects the emission of carbon dioxide, carbon monoxide, and methane. The chosen biomass was Eucalyptus citriodora, a very abundant species in Brazil, utilized in many industrial applications, including combustion for energy generation. Analyses by gas chromatograph and specific online instruments were used to determine the concentrations of the main emitted gases, and the following figures were found for the emission factors: 1400 ± 101 g kg-1 of CO2, 50 ± 13 g kg-1 of CO, and 3.2 ± 0.5 g kg-1 of CH4, which agree with values published in the literature for biomass from the Amazon rainforest. Statistical analysis of the experiments determined that specimen size most significantly affected the emission of gases, especially CO2 and CO. •Statistical analysis to determine effects on emission factors.•CO2, CO, CH4 emission factors determined for combustion of Eucalyptus.•Laboratory results agreed with data for Amazonian biomass combustion in field tests.•Combustion behavior under flaming and smoldering was analyzed. © 2013 Elsevier Ltd.

Purification and Characterization of an Ethanol-Tolerant β-Glucosidase from Sporidiobolus pararoseus and Its Potential for Hydrolysis of Wine Aroma Precursors

An extracellular ethanol-tolerant β-glucosidase from Sporidiobolus pararoseus was purified to homogeneity and characterized, and its potential use for the enhancement of wine aroma was investigated. The crude enzymatic extract was purified in four steps (concentration, dialysis, ultrafiltration, and chromatography) with a yield of around 40 % for total activity. The purified enzyme (designated Sp-βgl-P) showed a specific activity of approximately 20.0 U/mg, an estimated molecular mass of 63 kDa after sodium dodecyl sulfate polyacrylamide gel electrophoresis, and isoelectric point of 5.0 by isoelectric focusing. Sp-βgl-P has optimal activity at pH 4.0 and at 55 °C. It was stable in a broad pH range at low temperatures and it was tolerant to ethanol and glucose, indicating suitable properties for winemaking. The hydrolysis of glycosidic terpenes was analyzed by adding Sp-βgl-P directly to the wines. The released terpene compounds were evaluated by gas chromatography/mass spectrometry. The enzymatic treatment significantly increased the amount of free terpenes, suggesting that this enzyme could potentially be applicable in wine aroma improvement. © 2013 Springer Science+Business Media New York.

Deposition of Al2O3 by resistive evaporation and thermal oxidation of Al to be applied as a transparent FET insulating layer

Alumina thin films have been obtained by resistive evaporation of Al layer, followed by thermal oxidation by means of annealing in appropriate atmosphere (air or O2-rich), with variation of annealing time and temperature. Optical and structural properties of the investigated films reveal that the temperature of 550 °C is responsible for reasonable oxidation, which is accelerated up to 8 times for O2-rich atmosphere. Results of surface electrical resistivity and Raman spectroscopy are in good agreement with these findings. Surprisingly, X-ray and Raman data suggest also the crystallization of Si nuclei at glass substrate-alumina interface, which would come from the soda-lime glass used as substrate. © 2013 Elsevier Ltd and Techna Group S.r.l.

Characterization of the co-purified invertase and beta-glucosidase of a multifunctional extract from Aspergillus terreus

The filamentous fungus Aspergillus terreus secretes both invertase and beta-glucosidase when grown under submerged fermentation containing rye flour as the carbon source. The aim of this study was to characterize the co-purified fraction, especially the invertase activity. An invertase and a beta-glucosidase were co-purified by two chromatographic steps, and the isolated enzymatic fraction was 139-fold enriched in invertase activity. SDS-PAGE analysis of the co-purified enzymes suggests that the protein fraction with invertase activity was heterodimeric, with subunits of 47 and 27 kDa. Maximal invertase activity, which was determined by response surface methodology, occurred in pH and temperature ranges of 4.0-6.0 and 55-65 A degrees C, respectively. The invertase in co-purified enzymes was stable for 1 h at pH 3.0-10.0 and maintained full activity for up to 1 h at 55 A degrees C when diluted in water. Invertase activity was stimulated by 1 mM concentrations of Mn2+ (161 %), Co2+ (68 %) and Mg2+ (61 %) and was inhibited by Al3+, Ag+, Fe2+ and Fe3+. In addition to sucrose, the co-purified enzymes hydrolyzed cellobiose, inulin and raffinose, and the apparent affinities for sucrose and cellobiose were quite similar (K-M = 22 mM). However, in the presence of Mn2+, the apparent affinity and V-max for sucrose hydrolysis increased approximately 2- and 2.9-fold, respectively, while for cellobiose, a 2.6-fold increase in V-max was observed, but the apparent affinity decreased 5.5-fold. Thus, it is possible to propose an application of this multifunctional extract containing both invertase and beta-glucosidase to degrade plant biomass, thus increasing the concentration of monosaccharides obtained from sucrose and cellobiose.

Thermochemical equilibrium modeling of a biomass downdraft gasifier: Constrained and unconstrained non-stoichiometric models

The objective of this work is to develop a non-stoichiometric equilibrium model to study parameter effects in the gasification process of a feedstock in downdraft gasifiers. The non-stoichiometric equilibrium model is also known as the Gibbs free energy minimization method. Four models were developed and tested. First a pure non-stoichiometric equilibrium model called M1 was developed; then the methane content was constrained by correlating experimental data and generating the model M2. A kinetic constraint that determines the apparent gasification rate was considered for model M3 and finally the two aforementioned constraints were implemented together in model M4. Models M2 and M4 showed to be the more accurate among the four developed models with mean RMS (root mean square error) values of 1.25 each.Also the gasification of Brazilian Pinus elliottii in a downdraft gasifier with air as gasification agent was studied. The input parameters considered were: (a) equivalence ratio (0.28-035); (b) moisture content (5-20%); (c) gasification time (30-120 min) and carbon conversion efficiency (80-100%). (C) 2014 Elsevier Ltd. All rights reserved.

Cellular and molecular studies of the effects of a selective COX-2 inhibitor celecoxib in the cardiac cell line H9c2 and their correlation with death mechanisms

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Multi-scale structural and chemical analysis of sugarcane bagasse in the process of sequential acid-base pretreatment and ethanol production by Scheffersomyces shehatae and Saccharomyces cerevisiae

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

Prediction of the combustion process in fluidized bed based on physical-chemical properties of biomass particles and their hydrodynamic behaviors

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A study of the main oxidation products of natural pyrite by voltammetric and photoelectrochemical responses

(Photo)electrochemical experiments on pyrite electrodes in acetic acid-acetate buffer (pH = 4.5) are conducted to clarify the main oxidation reactions and the nature of the products. Electrochemical reactions in the -0.40 to 1.25 V (SHE) potential range are studied, and the production of iron (III) polysulfide from anodically formed iron oxides and polysulfides is discussed. Charges experimentally obtained are considered for the estimation of the most likely stoichiometry of the metallic polysulfide. The photoselectivity of the pyrite corrosion process indicates that the oxidation reactions of Fe2+ and S-2(2-) an not consecutive. The changes in stoichiometry and/or annihilation of crystalline structure defects are responsible for the observed photosensitivity of pyrite. A description of light effects on the interfacial behaviour and stability of pyrite is presented in terms of conduction and valence band energies, and thermodynamic potentials. (C) 2001 Elsevier Science B.V. All rights reserved.

ESI(+)-MS and GC-MS Study of the Hydrolysis of N-Azobenzyl Derivatives of Chitosan

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

Assessment of fungi in soils of sugarcane crops and their potential for production of biomass-degrading enzymes

Soil management practices are konwn to affect the biomass and enzyme activities of microbial soil communities. To assess whether burning of sugarcane prior to harvesting affects the community of soilborne fungi, we collected soil simples in two sites: burned sugarcane culture prior harvesting (BS) and non-burned sugarcane culture (NBS). A total of 75 filamentous fungal isolates were recovered from soils in both sites. Trichoderma was the most prevalent genus in both sites, followed by Fusarium, Cunninghamella and Aspergillus. The Sorensen's index (0.60) suggested a slight difference in fungi associated with both areas, with high number of fungal isolates found on BB soil. The abundance of Trichoderma isolates in NBS soil was higher than BS soil; however, the abundance of Fusarium, Aspergillus and Cunninghamella was higher in the latter type of soil. In addition, fungi isolated from BS soil showed the highest production of xylanase and laccase in comparision with fungi isolated form NBS soil. Our results indicate that the different types of sugarcane harvesting apparently did not interfere with the diversity of fungal communnities as revealed by culture-dependent methods. In addition, our data indicates the potencial of fungi from soils of sugarcane crops to produce relevant enzymes related to biomass conversion.

A flexible lab-on-a-chip for the synthesis and magnetic separation of magnetite decorated with gold nanoparticles

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

Electrochemical behaviour of (N-R-4-cyanopyridinium)pentaammineruthenium(II) derivatives in acidic medium. Hydrolysis of coordinated nitriles

The electrochemical behaviour of N-R-4-cyanopyridinium (4-rcp) (R = methyl, decyl, dodecyl, or benzyl) coordinated to pentaammineruthenium(II) in CF3COOH-CF3COONa (μ = 0.1 M, pH 3) aqueous medium was studied by means of cyclic voltammetry and constant potential electrolysis. The electrochemical oxidation of the metallic centre (Ep ca 0.51 V/SCE) can be described as a reversible monoelectronic charge-transfer followed by an irreversible chemical reaction, which is the hydrolysis of N-R-4-cyanopyridiniumpentaammineruthenium(III) (A) to N-R-4-carboxamidepyridiniumruthenium (III) (B) with the kf1 values depending on the type of alkyl group. The E 1 2 values are not significantly influenced by the nature of the alkyl group. At more negative potential (ca -0.5 V/SCE), B undergoes an electrochemical reduction followed by an aquation reaction to produce aquopentaammineruthenium(II) and free N-R-4-carboxamidepyridinium. The amide was identified by comparison of its cyclic voltammogram and UV-vis spectrum with that of a sample prepared by chemical reaction. The results were also discussed by comparison with other systems, and show that nitrile-amide conversion catalysed by pentaammineruthenium(II) complexes is possible. © 1994.