108 resultados para membrane permeation of gases

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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

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The effects of the Linear Alkylbenzene Sulphonate (LAS) were evaluated on the mussel Perna perna (Linnaeus, 1758), using a cellular level biomarker. The Neutral Red Retention Time (NRRT) assay was used to estimate effects at cellular levels. Significant effects were observed for the NRRT assay, even in low concentrations. The effects at cellular level were progressive, suggesting that the organisms are not capable to recover of such increasing effects. Additionally, the results show that the levels of LAS observed for Brazilian coastal waters may chronically affect the biota.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Using a freeze-etch technique the cytoplasmic and plasma membrane ultrastructure of Paracoccidiodies brasiliensis yeast-phase cells was studied. The multinucleate yeast-phase cells which grow by simultaneous multiple budding, like those of Mucor sp. contain several nuclei, mitochondria, well-developed ER, small vacuoles and lipid droplets. Complex structures with no apparent connexion to the plasma membrane of P. brasiliensis usually lack inveginations, but invaginations which do occur are always rod-shaped which indicates P. brasiliensis to be of either ascomycetous or basidiomycetous origin.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Six groups of 6 rats received equal doses (0.8 ml/100 g of body weight) of different rabbit anti rat kidney sera. The titer of anti GBM antibodies in the sera was evaluated by indirect immunofluorescent test in isolated GBM (IIT GBM). Rats of groups 1, 2, 3, 5, 6 received anti rat GBM sera with titers of 1/320, 1/240, 1/160, 1/60, 1/30 respectively. Group 4 received anti rat kidney serum with a titer of 1/80. The rats of group 1 died from 1 to 5 minutes after inoculation and their kidney were congested, with hialine trombi occluding arterioles and glomerular capillaries. The rats of group 2 and one of group 3 died from 2 to 15 days after inoculation and diffuse cortical necrosis was found. The remaining rats were sacrificed 2 months after inoculation. The kidneys were normal in control group; chronic membranoproliferative glomerulonephritis was observed in group 3 and 4, membranoproliferative glomerulonephritis in group 5 and minimal changes in group 6. By immunofluorescence rabbit gammaglobulin was seen in GBM of group 3, 4, 5 and 6. The IIT GBM performed in the eluates of the kidneys revealed the presence of heterologous antibody in groups 1, 2, 3, 4, 5 and 6 and autologous antibody in groups 3, 4 and 5. One concludes that the IIT GBM identifies and quantifies antibodies which have the property of damaging the kidney.

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The aim of the present work was to evaluate plasma membrane integrity, motility, vigor and morphology of fresh and frozen goat spermatozoa with or without seminal plasma. Semen samples were diluted in Tris solution, before and after thawing, with a combination of carboxifluorescein diacetate and propidium iodide. The results showed differences (P < 0.01) for motility and minor defects in the presence or absence of seminal plasma, for both fresh and frozen samples. Periods of collection had a significant effect on motility, probably due to changes in the photoperiod. Plasma membrane integrity was significantly reduced by the freezing process, whether seminal plasma was present or absent. In conclusion, removal of seminal plasma decreased motility and vigor rates in frozen samples. The photoperiod probably decreased the testosterone level, contributing negatively to the high percentage of sperm abnormalities, mainly damaged membranes. The use of fluorescent probes allowed a better estimation of the percentage of functional cells, instead of only estimating the percentage of motile cells or morphology defects. © 2001 Elsevier Science B.V. All rights reserved.

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In the present study, different freezing systems (Styrofoam box and Mini Digitcool ZH 400) and storage volumes (0.5- and 0.25-mL straws) were compared with regard to sperm kinetics and plasma membrane integrity of frozen and thawed semen. For that, three ejaculates from four animals were frozen in Styrofoam box and Mini Digitcool ZH 400 machine. The 0.5-mL straws were thawed at 46°C for 20 seconds, and the 0.25-mL straws were thawed at 46°C for 12 seconds. Statistical analysis was performed using program R of descriptive analysis box plot, followed by analysis of variance using PROC MIXED of SAS 9.1 package. Variances of 5% were considered as different. There was no interaction between the straw sizes and volumes; however, statistical differences were observed between the semen storage volumes. The 0.5-mL straws had higher total motility (%), progressive motility (%), average path velocity (μm/s), straight-line velocity (μm/s), curvilinear velocity (μm/s), and rapid sperm percentage (%) than the 0.25-mL straws. However, plasma membrane integrity analysis did not differ between the two straws. Thus, it is possible to conclude that equine sperm cryopreserved in 0.5-mL straws has better sperm kinetics than when stored in 0.25-mL straws. Additionally, it is possible to conclude that automated systems that enable faster freezing rates result in a seminal quality that is similar to the one obtained by the conventional system using Styrofoam boxes. © 2013 Elsevier Inc.

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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.

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To evaluate the ability of low time microwaveexposureto inactivate and damage cell membrane integrity of C. albicans. Materials and Methods: Two 200ml C. albicans suspensions were obtained. Sterile dentures were placed in a beaker containing Experimental (ES) or Control suspensions (CS). ES was microwaved at 650 W for 1, 2, 3, 4 or 5 min. Suspensions were optically counted using Methylene blue dye as indicative of membrane-damaged cells; spread on Agar Sabouraud dextrose (ASD) for viability assay; or spectrophotometrically measured at 550nm. Cell-free solutions were submitted to content analyses of protein (Bradford and Pyrogallol red methods); Ca++ (Cresolphthalein Complexone method); DNA (spectrophotometer measurements at 260nm) and K+ (selective electrode technique). Data were analyzed by Student-t test and linear regression (α=0.05). In addition, flowcytometry analysis of Candida cells in suspensionwas performed using propidium iodide. Results: All ES cells demonstrated cell membrane damage at 3, 4 and 5 min,viable cells were nonexistent at 3, 4 and 5 min ES ASD plates and optical density of ES and CS was not significantly differentfor all exposition times. ES cells released highcontents of protein, K+ , Ca++ and DNA after 2 min exposition when compared to that of the CSs. Similar results were observed with flow cytometry analysiswith regard to the periodsof microwave exposure. Conclusions: Microwave irradiation inactivated C. albicansafter 3min and damaged cell membrane integrity after 2 min exposition.

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Objective: the proposal was to study the presence of immunoglobulin A (IgA) in the chorioamniotic membrane of healthy postpartum women with premature rupture of the chorioamniotic membrane (FROM). Method: A single radial immunodiffusion technique was used to quantify the IgA in the chorioamniotic membrane tissues. Results: the level of IgA was approximately 10 times higher in patients whose membranes had been ruptured for > 10 h (24.58 mg/dl). These results were compared with those of a previously published study where the mean of amount of IgA was 2.52 mg/dl in membranes of patients with rupture < 10 h. Our results show that IgA began to rise after 10-15 h following rupture. Conclusion: Although more studies need to be performed our data indicate that the increasing IgA in our patients after 10 h of latency probably represents the beginning of an ascending colonization of bacteria which could be the source of future infection.