Electrochemical studies of copper, copper-aluminium and copper-aluminium-silver alloys: Impedance results in 0.5M NaCl

The electrochemical behaviour of Cu, Cu-Al and Cu-Al-Ag alloys in aqueous solutions of NaCl (0.5 M, pH = 3.00) was studied by means of voltammetric methods and electrochemical impedance spectroscopy. The surfaces were examined by SEM and EDX analysis. Cu-Al-Ag alloy shows a potentiodynamic behaviour similar to that of the pure copper electrode while the Cu-Al alloy presents some minor differences. In the active dissolution region the electrodes suffer pitting corrosion and in the other potential regions there are the formation of a passivant film with composition depending on the potential. The impedance responses of the electrodes are discussed. An electrodissolution mechanism is proposed and the effect of the alloying elements upon the impedance response and polarisation curves is explained. The main effects are due to the production of copper and silver chlorides and aluminium oxides/ hydroxides at the corroding interface. The addition of Al or (Al + Ag) increases the corrosion resistance of pure copper. © 1995.

Renal and vascular effects of Crotalus durissus cumanensis venom and its crotoxin fraction

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Interaction between the septal area and the subfornical organ in the control of water intake induced by thirst-eliciting procedures

Rats bearing lesions in the septal area followed by lesions in the subfornical organ were submitted to various thirst-eliciting procedures. The rats with hyperdipsia induced by lesions of the septal area drank more water than either during the control period or after lesion of the subfornical organ under the same thirst-eliciting or angiotensin-liberating stimuli (polyethyleneglycol, isoproterenol, water deprivation and ligation of the inferior vena cava). The overdrinking elicited by lesions in the septal area was blocked after lesion of the subfornical organ. Neither hypovolemia, nor hypotension or water deprivation could elicit increased water intake in animals whose subfornical organ had been destroyed. Animals with lesions in the subfornical organ showed decreased water intake after cellular dehydration. The results obtained suggest that the subfornical organ acts as a more important structure than the septal area in the regulation of water intake elicited by angiotensin, with two opposite effects: a direct one facilitating water intake, and an indirect one inhibiting the septal area. The septal area has an inhibitory effect on the subfornical organ and on water intake. © 1980.

Bothropoides pauloensis venom effects on isolated perfused kidney and cultured renal tubular epithelial cells

Coordenadação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A technique for the determination of the available oxygen in living carp (Cyprinus carpio) muscle

1. 1. A polarographic method for the measurement of the available oxygen in the muscle of living carp by the use of a platinum microelectrode is proposed. 2. 2. The oxygen and the reference electrodes were assembled in a single insertion piece which was implanted in the muscle of a living carp maintained in a special experimental chamber. 3. 3. Curves for normal oxygen levels corresponding to air-saturated water, as well as to a carbogene-saturated water, were obtained. 4. 4. The method can be considered adequate for the measurement of tissue oxygen in living fishes. © 1984.

Biofilm formation on the surface of Ti–7.5Mo alloy after surface treatment

Purpose: In the present work, a susceptibility and efficacy of the Ti–7.5Mo alloy and Ti alloy to bacterial biofilm formation after surface treatment was evaluated. Methods and materials: The alloy Ti–7.5Mo was obtained in arc furnace under an argon atmosphere. Ingots were then homogenized under vacuum at 1100 °C for 86.4 ks to eliminate chemical segregation and after cold worked discs were cutting. Samples were immersed in NaOH aqueous solution (5 M) and treated at 450 °C. Biofilms were grown in Ti–7.5Mo discs immersed in sterile brain heart infusion broth (BHI)containing 5% sucrose, inoculated with microbial suspension (106 cells/ml) and incubated for 5 days. Next, the discs were placed in tubes with sterile physiological solution 0.9% sodium chloride (NaCl) and sonicated for to disperse the biofilms. Tenfold serial dilutions were carried and aliquots seeded in selective agar, which were then incubated for 48 h. Then, the numbers CFU/ml (log 10) were counted and analyzed statistically. Scanning electron microscopy (SEM) on discs with biofilms groups was performed, atomic force microscope (AFM) and contact angle. Results: The results show that there is a 5% difference in bacterial adhesion between pure titanium and Ti–7.5Mo alloy. Conclusion: It was concluded that the greater the roughness, the greater the hydrophilic effect.

Caracterização dos compostos derivados de furoxano como inibidores da atividade de bombas de efluxo em Mycobacterium tuberculosis e estudo da influência do efluxo e da halotolerância nos perfis de resistência do bacilo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito do fator de crescimento epidermal (EGF) na maturação in vitro de oócitos caninos

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

Splenic congestion associated with acepromazine administration in dogs

The effects splenic dilatation induced by acepromazine in a prospective, randomized study. Thirtythree adult mongrel dogs were divided into two groups designated as AG (acepromazine 0.05 mg/kg, i.v., n = 23) and CG (0.9% sodium chloride administered at a similar volume, n = 10). In both groups underwent sonographic examinations before (T0) and fifteen minutes (T15) after drug injection. The thickness spleen and splenic vein width were measured. Higher thickness was found in the AG group at T15 (2.47 cm) when compared to that at T0 (2.06 cm, p = 0.016), while the T0 (2.33 cm) and T15 (2.39 cm) measures did not differ within the CG group. Moreover, the splenic vein width was higher (p = 0.013) at T15 than at T0 in the AG group. Based on results of this study, we concluded that acepromazine, in doses of 0.05 mg/kg, promotes splenomegaly in dogs after fifteen minutes of the injection.

Determinação de atividade de água, umidade e sal em peixes salgados e secos importados

Brazil is a major importer in the world salted fish trade. The sale of these products must meet the established standards, based mainly on the salt and moisture levels. The aim of this study was to analyze the salt and moisture levels in imported Atlantic cod and Pacific cod, and in the dried salted fish Ling, Zarbo and Saithe, which are not classified as cod since they do not belong to the genus Gadus. The water activity was also analyzed, which could be a useful parameter to determine the quality of salted fish.The results showed that the legal limits for salt were much lower than the values found in the analyses. The moisture contents established for the category of salted fish, as determined by the Portuguese legislation, were more reliable. We suggest the inclusion of the water activity as a parameter for the evaluation of these products.

Sementes de leguminosas forrageiras sob estresse salino tratadas com ácido salicílico e espermidina

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento de um embutido cárneo fermentado, com teores reduzidos de gordura e sais de cura, através da utilização de culturas probióticas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Atividade antibacteriana de óleo essencial de orégano (Origanum vulgare): ações in vitro e in situ para preservação de alimento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos do corticosteroide injetado no tendão calcâneo de coelhos: análise histológica, biomecânica e das expressões de metaloproteinases e interleucinas

Pós-graduação em Bases Gerais da Cirurgia - FMB

Interaction of sodium cholate with dioctadecyldimethylammonium chloride vesicles in aqueous dispersion

Mixtures of dioctadecyldimethylammonium chloride (DODAC) cationic vesicle dispersions with aqueous micelle solutions of the anionic sodium cholate (NaC) were investigated by differential scanning calorimetry, DSC, turbidity and light scattering. Within the concentration range investigated (constant 1.0 mM DODAC and varying NaC concentration up to 4 mM), vesicle -> micelle -> aggregate transitions were observed. The turbidity of DODAC/NaC/water depends on time and NaC/DODAB molar concentration ratio R. At equilibrium, turbidity initially decreases smoothly with R to a low value (owing to the vesicle-micelle transition) when R = 0.5-0.8 and then increases steeply to a high value (owing to the micelle-aggregate transition) when R = 0.9-1.0. DSC thermograms exhibit a single and sharp endothermic peak at T-m approximate to 49 degrees C, characteristic of the melting temperature of neat DODAC vesicles in water. Upon addition of NaC, T-m initially decreases to vanish around R = 0.5, and the main transition peak broadens as R increases. For R > 1.0 two new (endo- and exothermic) peaks appear at lower temperatures indicating the formation of large aggregates since the dispersion is turbid. All samples are non-birefringent. Dynamic light scattering (DLS) data indicate that both DODAC and DODAC/NaC dispersions are highly polydisperse, and that the mean size of the aggregates tends to decrease as R increases. (c) 2006 Elsevier B.V. All rights reserved.