Inorganic elemental analysis and identification of residual monomers released from different glass ionomer cements in cell culture medium

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Analysis of a microbial community associated with polychlorinated biphenyl degradation in anaerobic batch reactors

The degradation of polychlorinated biphenyls (PCBs) was investigated under fermentativemethanogenic conditions for up to 60 days in the presence of anaerobic biomass from a full-scale UASB reactor. The low methane yields in the PCBs-spiked batch reactors suggested that the biomass had an inhibitory effect on the methanogenic community. Reactors containing PCBs and co-substrates (ethanol/ sodium formate) exhibited substantial PCB reductions from 0.7 to 0.2 mg mL-1 . For the Bacteria domain, the PCBs-spiked reactors were grouped with the PCB-free reactors with a similarity of 55 %, which suggested the selection of a specific population in the presence of PCBs. Three genera of bacteria were found exclusively in the PCB-spiked reactors and were identified using pyrosequencing analysis, Sedimentibacter, Tissierela and Fusibacter. Interestingly, the Sedimentibacter, which was previously correlated with the reductive dechlorination of PCBs, had the highest relative abundance in the RCS-PCB (7.4 %) and RCS-PCB-PF (12.4 %) reactors. Thus, the anaerobic sludge from the UASB reactor contains bacteria from the Firmicutes phylum that are capable of degrading PCBs.

Biological Hydrogen production from environmental sample in tropical countries

The hydrogen gas is regarded as clean and renewable energy source, since it generates only water during combustion when used as fuel. It shows 2.75 times more energy content than any hydrocarbon and it can be converted into electrical, mechanical energy or heat. Inoculum sources have been successfully tested for hydrogen biological production in temperate climate countries as sludge treatment plants sewage, sludge treatment plant wastewater, landfill sample, among others. However, hydrogen biologic production with inoculum from environmental samples such as sediment reservoirs, especially in tropical countries like Brazil, is rarely investigated. Reservoirs and fresh water lake sediment may contain conditions for the survival of a wide variety of microorganisms which use different carbon sources mainly glucose and xylose, in the fermentation. Glucose is an easily biodegradable, present in most of the industrial effluents and can be obtained abundantly from agricultural wastes. A wide variety of wastewater resulting from agriculture, industry and pulp and paper processed from wood may contain xylose in its constitution. Such effluent contains glucose and xylose concentrations of about 2 g/L. In this sense, this work verified hydrogen biological production in anaerobic batch reactor (1L), at 37 ° C, initial pH 5.5, headspace with N2 (100%), Del Nery medium, vitamins and peptone (1 g/L), fed separately with glucose (2g/L) and xylose (2 g/L). The inoculum was taken from environmental sample (sediment reservoir Itupararanga - Ibiúna - SP-Brazil). It was previously purified in serial dilutions at H2 generation (10-5, 10-7, 10-10), and heat treated (90º C - 10 min) later to inhibited the H2 consumers. The maximum H2 generations obtained in both tests were observed at 552 h, as described below. At the reactors fed with glucose and xylose were observed, respectively, 9.1 and 8.6 mmol H2/L, biomass growth (0.2 and 0.2 nm); consumption of sugar concentrations 53.6% (1.1 glucose g/L) and 90.5% (1.8 xylose g/L); acetic acid generation (124.7 mg/L and 82.7 mg/L), butyric acid (134.0 mg/L and 230.4 mg/L) and there wasn’t methane generation in the reactors. Microscopic analysis of biomass in anaerobic reactors showed the predominance of Gram positive rods and rods with endospores, whose morphology is characteristic of H2-generating bacteria, in both tests. These species were selected from the natural environment. In DGGE analysis performed difference were observed between populations from inoculum and in tests. This analysis confirmed that some species of bacteria were selected which remained under the conditions imposed on the experiment. The efficiency of the pre-treatment of inoculum and the imposition of pH 5.5 inhibited methane-producing microorganisms and the consumers of H2. Therefore, the experimental conditions imposed allowed the attainment of bacterial consortium of producer H2 taken from an environmental sample with concentration of xylose and glucose similar to the ones of the industrial effluents.

Dose-Response and Time-Course of a-Tocoferol Mediating the Cytoprotection Of Dental Pulp Cells Against Hydrogen Peroxide

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Kinetic study of the co-firing of bagasse-sludge blends

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Potential application of Ganoderma lucidum in solid state fermentation of primary sludge and wheat straw

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Black liquor gasification combined cycle with CO2 capture-Technical and economic analysis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Transdentinal cytotoxicity of resin-based luting cements to pulp cells

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

Human immature dental pulp stem cells share key characteristic features with limbal stem cells

Objectives: Limbal stem cells (LSC) are self-renewing, highly proliferative cells in vitro, which express a set of specific markers and in vivo have the capacity to reconstruct the entire corneal epithelium in cases of ocular surface injury. Currently, LSC transplantation is a commonly used procedure in patients with either uni- or bilateral total limbal stem cells deficiency (TLSCD). Although LSC transplantation holds great promise for patients, several problems need to be overcome. In order to find an alternative source of cells that can partially substitute LSC in cornea epithelium reconstruction, we aimed at investigating whether human immature dental pulp stem cells (hIDPSC) would present similar key characteristics as LSC and whether they could be used for corneal surface reconstruction in a rabbit TLSCD model. Materials: We used hIDPSC, which co-express mesenchymal and embryonic stem cell markers and present the capacity to differentiate into derivative cells of the three germinal layers. TLSCD was induced by chemical burn in one eye of rabbits. After 30 days, the opaque tissue formed was removed by superficial keratectomy. Experimental group received undifferentiated hIDPSC, while control group only received amniotic membrane (AM). Both groups were sacrificed after 3 months. Results and conclusions: We have demonstrated, using immunohistochemistry and reverse transcription-polymerase chain reaction, that hIDPSCs express markers in common with LSC, such as ABCG2, integrin beta 1, vimentin, p63, connexin 43 and cytokeratins 3/12. They were also capable of reconstructing the eye surface after induction of unilateral TLSCD in rabbits, as shown by morphological and immunohistochemical analysis using human-specific antibodies against limbal and corneal epithelium. Our data suggest that hIDPSCs share similar characteristics with LSC and might be used as a potential alternative source of cells for corneal reconstruction.

Detecting an abnormality in a recovery boiler using dynamic multivariate data analysis with parallel coordinate plots

Data visualization techniques are powerful in the handling and analysis of multivariate systems. One such technique known as parallel coordinates was used to support the diagnosis of an event, detected by a neural network-based monitoring system, in a boiler at a Brazilian Kraft pulp mill. Its attractiveness is the possibility of the visualization of several variables simultaneously. The diagnostic procedure was carried out step-by-step going through exploratory, explanatory, confirmatory, and communicative goals. This tool allowed the visualization of the boiler dynamics in an easier way, compared to commonly used univariate trend plots. In addition it facilitated analysis of other aspects, namely relationships among process variables, distinct modes of operation and discrepant data. The whole analysis revealed firstly that the period involving the detected event was associated with a transition between two distinct normal modes of operation, and secondly the presence of unusual changes in process variables at this time.

Exergy efficiency analysis of chemical and biochemical stages involved in liquid biofuels production processes

Liquid biofuels can be produced from a variety of feedstocks and processes. Ethanol and biodiesel production processes based on conventional raw materials are already commercial, but subject to further improvement and optimization. Biofuels production processes using lignocellulosic feedstocks are still in the demonstration phase and require further R&D to increase efficiency. A primary tool to analyze the efficiency of biofuels production processes from an integrated point of view is offered by exergy analysis. To gain further insight into the performance of biofuels production processes, a simulation tool, which allows analyzing the effect of process variables on the exergy efficiency of stages in which chemical or biochemical reactions take place, were implemented. Feedstocks selected for analysis were parts or products of tropical plants such as the fruit and flower stalk of banana tree, palm oil, and glucose syrups. Results of process simulation, taking into account actual process conditions, showed that the exergy efficiencies of the acid hydrolysis of banana fruit and banana pulp were in the same order (between 50% and 60%), lower than the figure for palm oil transesterification (90%), and higher that the exergy efficiency of the enzymatic hydrolysis of flower stalk (20.3%). (C) 2011 Elsevier Ltd. All rights reserved.

Cytogenetic instability of dental pulp stem cell lines

Human adult stem cells (hASCs) offer a potentially renewable source of cell types that are easily isolated and rapidly expanded for use in regenerative medicine and cell therapies without the complicating ethical problems that are associated with embryonic stem cells. However, the eventual therapeutic use of hASCs requires that these cells and their derivatives maintain their genomic stability. There is currently a lack of systematic studies that are aimed at characterising aberrant chromosomal changes in cultured ASCs over time. However, the presence of mosaicism and accumulation of karyotypic abnormalities within cultured cell subpopulations have been reported. To investigate cytogenetic integrity of cultured human dental stem cell (hDSC) lines, we analysed four expanded hDSC cultures using classical G banding and fluorescent in situ hybridisation (FISH) with X chromosome specific probe. Our preliminary results revealed that about 70% of the cells exhibited karyotypic abnormalities including polyploidy, aneuploidy and ring chromosomes. The heterogeneous spectrum of abnormalities indicates a high frequency of chromosomal mutations that continuously arise upon extended culture. These findings emphasise the need for the careful analysis of the cytogenetic stability of cultured hDSCs before they can be used in clinical therapies.

2D-DIGE analysis of mango (Mangifera indica L.) fruit reveals major proteomic changes associated with ripening

A comparative proteomic investigation between the pre-climacteric and climacteric mango fruits (cv. Keitt) was performed to identify protein species with variable abundance during ripening. Proteins were phenol-extracted from fruits, cyanine-dye-labeled, and separated on 2D gels at pH 4-7. Total spot count of about 373 proteins spots was detected in each gel and forty-seven were consistently different between pre-climacteric and climacteric fruits and were subjected to LC-MS/MS analysis. Functional classification revealed that protein species involved in carbon fixation and hormone biosynthesis decreased during ripening, whereas those related to catabolism and the stress-response, including oxidative stress and abiotic and pathogen defense factors, accumulated. In relation to fruit quality, protein species putatively involved in color development and pulp softening were also identified. This study on mango proteomics provides an overview of the biological processes that occur during ripening. (C) 2012 Elsevier B.V. All rights reserved.

Sewage sludge does not induce genotoxicity and carcinogenesis

Through a series of experiments, the genotoxic/mutagenic and carcinogenic potential of sewage sludge was assessed. Male Wistar rats were randomly assigned to four groups: Group 1 - negative control; Group 2 - liver carcinogenesis initiated by diethylnitrosamine (DEN; 200 mg/kg i.p.); Group 3 and G4-liver carcinogenesis initiated by DEN and fed 10,000 ppm or 50,000 ppm of sewage sludge. The animals were submitted to a 70% partial hepatectomy at the 3rd week. Livers were processed for routine histological analysis and immunohistochemistry, in order to detect glutathione S-transferase positive altered hepatocyte foci (GST-P+ AHF). Peripheral blood samples for the comet assay were obtained from the periorbital plexus immediately prior to sacrificing. Polychromatic erythrocytes (PCEs) were analyzed in femoral bone-marrow smears, and the frequencies of those micronucleated (MNPCEs) registered. There was no sewage-sludge-induced increase in frequency of either DNA damage in peripheral blood leucocytes, or MNPCEs in the femoral bone marrow. Also, there was no increase in the levels of DNA damage, in the frequency of MNPCEs, and in the development of GST-P AHF when compared with the respective control group.

Proteomic analysis of papaya fruit ripening using 2DE-DIGE

Papayas have a very short green life as a result of their rapid pulp softening as well as their susceptibility to physical injury and mold growth. The ripening-related changes take place very quickly, and there is a continued interest in the reduction of postharvest losses. Proteins have a central role in biological processes, and differential proteomics enables the discrimination of proteins affected during papaya ripening. A comparative analysis of the proteomes of climacteric and pre-climacteric papayas was performed using 2DE-DIGE. Third seven proteins corresponding to spots with significant differences in abundance during ripening were submitted to MS analysis, and 27 proteins were identified and classified into six main categories related to the metabolic changes occurring during ripening. Proteins from the cell wall (alpha-galactosidase and invertase), ethylene biosynthesis (methionine synthase), climacteric respiratory burst, stress response, synthesis of carotenoid precursors (hydroxymethylbutenyl 4-diphosphate synthase, GcpE), and chromoplast differentiation (fibrillin) were identified. There was some correspondence between the identified proteins and the data from previous transcript profiling of papaya fruit, but new, accumulated proteins were identified, which reinforces the importance of differential proteomics as a tool to investigate ripening and provides potentially useful information for maintaining fruit quality and minimizing postharvest losses. (C) 2011 Elsevier B.V. All rights reserved.