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Number of results: 8
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Abstract

The aim of the study was to investigate the effect of soybean lecithin as a substitute for egg yolk in milk and tris based extenders in ram semen cryopreservation. Twenty ejaculates were col- lected from four healthy, mature Wrzosówka rams (2-3 years of age). Each ejaculate was divided into four equal aliquots and diluted with four different extenders: 1) milk extender containing 5% egg yolk, 2) milk extender containing 1.5% soybean lecithin, 3) tris extender containing 20% egg yolk, 4) tris extender containing 1.5% soybean lecithin. Extended semen was loaded into 0.25 ml French straws, cooled and frozen in liquid nitrogen vapor. Total motility, curvilinear velocity, plasma membrane integrity and fertilizing ability of sperm were assessed after thawing. Total mo- tility was lower (p<0.05) in tris-soybean lecithin extender when compared to other extenders. Curvilinear velocity was higher (p<0.05) for spermatozoa cryopreserved in milk-soybean lecithin extender compared to other extenders tested. For the percentage of live sperm no significant difference was observed between extenders. The lambing rate were higher (not statistically signifi- cant) in ewes inseminated with semen doses frozen in milk-soybean lecithin extender (42.9%) than in the tris-egg yolk extender (16.7%). In conclusion, replacing the egg yolk with soybean lecithin was effective in milk but not in tris extender.
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Abstract

In the work five ceramic compounds based on the (K0.44Na0.52Li0.04)NbO3 (KNLN) material modified with oxides: Cr2O3, ZnO, Sb2O3 or Fe2O3 (in an amount of 0.5 mol.%) were obtained. The KNLN-type composition powder was prepared by solid phase synthesis from a mixture of simple oxides and carbonates, while compacted of the ceramic samples was conducted by free sintering methods. In the work the effect of the used admixture on the electrophysical properties of the KNLN ceramics was presented. The XRD, EDS tests, the SEM measurements of the morphology ceramic samples, dielectric properties and DC electric conductivity were conducted. The research showed that the used admixtures introduced into the base of KNLN-type composition improve the microstructure of the ceramic samples and improve their sinterability. In the case of the dielectric measurements, it was observed a decrease in the maximum dielectric permittivity at the TC for dopred KNLN-type samples. The addition of an admixture of chromium, zinc, antimony or iron in an amount of 0.5 mol.% to the base composition (K0.44Na0.52Li0.04)NbO3 practically does not change the phase transition temperature. The diminution in the density value of doped KNLN ceramics was attributed to the alkali elements volatilization.
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Abstract

The discovery of (BaxCa1-x)(ZryTi1-x)O3 lead-free ceramics drawn a lot of attention to those novel materials because of their excellent piezoelectric properties. However, quite a little attention has been paid to other features of the material. This article reports a wide range of research, including composition, structure and microstructure, dielectric response and impedance spectroscopy in order to systematize and expand knowledge about this peculiar ceramics and strontium doping effect on its properties. In order to test that influence a series of samples with various strontium concentration, precisely the admixtures of 0.02, 0.04 and 0.06 mol% were prepared, as well as basic ceramics to compare obtained results.
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