Renoprotective effect of contemporary blocking of angiotensin II and endothelin-1 in rats with membranous nephropathy

Glutathione has a central role in the defence against oxidative damage; however, the data on glutathione concentrations in the semen of infertile men are limited. To expand this knowledge the glutathione content of the ejaculates and blood plasmas of 77 infertile men and 11 controls were analysed. The concentrations of total glutathione were assessed in spermatozoa, seminal plasma and blood plasma using a coupled spectrophotometric assay. In the spermatozoa of patients with oligozoospermia the glutathione concentrations (2.57+/-0.96 nmol/10[8] spermatozoa; mean +/- SD) were significantly lower than in the controls (3.49+/-0.87 nmol/10[8] spermatozoa; P +/- 0.03). The glutathione content of spermatozoa from patients with normozoospermia showed large variations (3.04+/-1.37 nmol/10[8] spermatozoa). An association between the intracellular glutathione content and the ability to penetrate bovine cervical mucus was observed (r = 0.2, P = 0.04). The intracellular glutathione concentrations correlated with the glutathione levels in seminal plasma (r = 0.46, P < 0.0001). There was no correlation between glutathione concentrations in blood plasma and those in seminal plasma or in spermatozoa. The glutathione concentrations in seminal plasmas did not differ between the different groups, however, correlated with the serum follicle stimulating hormone concentrations (r = 0.53, P = 0.005). This study demonstrated that intracellular glutathione levels of spermatozoa are decreased in certain populations of infertile men.     

Influence of notch root radius on ductile rupture fracture toughness evaluation with Charpy-V type specimens

The blunt notch fracture toughness of four types of carbon-manganese steel (ASTM A516 grade 70) has been determined by J-integral tests on Charpy-V type samples with different values of notch root radius, ρ. J-ρ plots, determined using specimens with a notch depth to width ratio, a/w, equal to 0.5, have shown the existence of a limiting ρ value (ρ_eff) below which applied J-intergral values at fracture initiation are constant. These ρ_eff values have been seen to depend only on second-phase particle distribution and not on their volume fraction or on the steel ferritic grain size. The procedure for deriving J-integral values at the onset of stable crack growth from J resistance curves in the case of notches has also been discussed. Experiments with Charpy specimens with a/w = 0.2 do not allow the derivation of meaningful J-ρ plots. In all cases, a ductile fracture criterion based on the constancy of the notch tip strain at rupture initiation has been proved when ρ >ρ_eff.     

Synthesis and optical properties of sub-micron sized rare earth-doped zirconia particles

Sub-micron sized crystalline particles of Eu³⁺ and Er³⁺-doped zirconia (ZrO₂) were prepared via a wet chemical sol-gel route and post synthesis annealing. The doping was achieved by introduction of the respective rare earth salts into the zirconia precursor solution, with insitu generation of sodium chloride for stabilization of the particle surface during growth. A series of materials with differing europium content, nominally 0.3, 3 and 6 mol% within the ZrO₂ lattice, were prepared for respective comparison and characterization of their optical properties following annealing at 700 °C. Average emission lifetimes of up to 2.3 ms were observed for the Eu³⁺-doped particles. Particle sizes, approximated from SEM micrographs, were observed in the range 250-400 nm. The synthesis of Er³⁺-doped ZrO₂ particles (0.5 mol%) produced 300 nm sized particles which exhibited emission in the visible and infrared regions after annealing at 1000 °C. X-ray diffraction (XRD) with Rietveld analysis for phase quantification, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectra were used to characterize the samples.     

Neuroanatomical and immunohistochemical studies on the dorsal neurons in the spinal cord of Trigla lucerna L. and Scorpaena porcus L. (Scorpaeniformes)

Peculiar dorsal neurons present in the dorsal spinal cord of Trigla lucerna L. and Scorpaena porcus L. were investigated by neuroanatomical and immunohistochemical methods. These neurons were previously defined as commissural cells, but have now been identified as supramedullary neurons. The following fundamental criteria for identifying the supramedullary neurons of Teleosts are proposed: a) dorsomedial location in the spinal cord; b) large size of the soma and axon; c) immunoreactivity to gastrin/CCK-like peptides.     

Electrochemical behavior of cobalt oxide coatings on cold-rolled steel in alkaline sodium sulfate

The electrochemical behavior of a coating of cobalt oxide on cold-rolled steel in alkaline sodium sulfate was studied using the electrochemical techniques of open-circuit potential measurements and electrochemical impedance spectroscopy. The coating was prepared at different annealing temperatures ranging from 350 to 750 °C and characterized by SEM, EDX and XRD. Below 550 °C the composition of the coating was basically of Co₃O₄. At 750 °C CoO was formed and big cracks appeared on the film exposing an inner layer of iron oxides. Analysis of the EIS data is very difficult because of the complexity of the interface structure. It can be inferred that the charge transfer resistance of the coatings prepared at 350 and 450 °C were higher than those for the coatings prepared at temperatures above 550 °C.     

The influence of the electrochemical treatment on Cu-Al-Ag alloys in deaerated 0.5 M NaOH

The effect of consecutive cyclic polarization in de-aerated 0.5 M NaOH solutions on the surface microstructure of mechanically polished Cu-Al-Ag alloys of different compositions and heat treatments has been studied using optical microscopy, SEM and EDS. The current peaks of the cyclic polarization curves do not depend on the alloy composition in the composition range studied. The repetitive potential scans between H₂ and O₂ evolution in alkaline media lead to preferential dissolution of aluminium, the roughness and phase composition of the surface of the alloys changing significantly. The quasistationaryI-E curves of the different Cu-Al-Ag alloys studied consist in the superposition of the quasistationaryI-E curves of high-purity Cu and Ag, the EDS microanalysis showing that aluminium is not present on the surface of the alloy in these conditions.