In order to utilize the absolute gravity ( AG) measurements in terms of tectonic study it is necessary to reduce all disturbing environmental and instrumental effects. Many of those can be easily modelled and this step is done routinely during measurements (i.e. tide, polar motion, ocean tidal loading). Other remains in data and there is a lack of conventional models for them. Significant gravity variation is associated with changes of soil water at global scale. We study this effect for the Lower Silesia (South-western Poland) territory. Computed gravity changes can reach up to 2 μgal peak-to-peak amplitude with seasonal time scale. This effect is beyond of accuracy of modern ballistic gravimeter. Using real data collected with FG5 gravimeter we show here that neglecting of this phenomenon can lead to serious misinterpretation in term of secular gravity changes. This is emphasized especially when only sparse data of a few year time span is at our disposal. No attempt of modelling of local hydrology impact on effect was made, while in this study we concentrate on large scale water storage influence on measured gravity., Marcin Rajner, Tomasz Olszak, Jerzy Rogowski and Janusz Walo., and Obsahuje bibliografické odkazy
Test stand for investigation of the influence of bearing bushing movement control on behaviour of a rigid rotor supported in sliding journal bearings was designed. The stand was equipped with two pairs of piezoactuators, enabling to move each bearing bushing in two directions, and with two pairs of relative sensors tracing shaft movement at both bearings. The initial tests showed quite unexpected phenomena, which should be cleared up, before experiments with controlled bearing bushing movement could be started. Finally the system began to operate according to predictions and it was possible to start intended experiments. Some results of the rotor behaviour with and without piezoactuator action are presented.
To further investigate the role of insulin during preimplantation embryo development, we compared the effects of insulin on the development of mouse and bovine preimplantation embryos and on cell proliferation during culture in vitro in simplex media. The influence of insulin on the development of mouse zygotes was determined during cultivation in mSOF medium, alone or supplemented with glucose. Similarly, the effects of insulin on the bovine preimplantation embryo development were studied in mSOF medium. The addition of insulin into mSOF medium enhanced significantly the number of cells per mouse blastocyst. Moreover, when mSOF medium was supplemented with insulin and 0.2 mmol.l-1 glucose, the percentage of hatched blastocysts and the mean cell number of mouse blastocysts were significantly higher. Insulin had no significant effect on the development of bovine embryos, produced by in vitro fertilization of in vitro matured oocytes. Neither the rates of developing embryos nor the mean number of cells in blastocysts were different in comparison with control embryos. Our results suggest that the in vitro development of mouse embryos could be enhanced by the addition of insulin to the culture medium and is further improved by the addition of glucose. In contrast to this our results indicate that insulin has no detectable beneficial effect on the preimplantation development of bovine embryos in mSOF medium., J. Mihalik, P. Rehák, J. Koppel., and Obsahuje bibliografii
The article deals with the influence of phase modulated synthetic jet on the aerodynamics of the hump in a closed test section of the Eiffel-type wind tunnel. Three experimental methods of measurement techniques of this phenomenon, were used: the pressure profile using the Kiel total pressure probe, the velocity profile using the CTA probe and the visualization of the flow field using the hot film and the thermo camera. The experimental results with and without the influence of the synthetic jet were compared, as well the impact of the phase shift of the neighbouring synthetic jets. As a reference case, the flow around the hump without the influence of the syntheic jet was selected. The results of the measurement are presented in figures and compared. and Obsahuje seznam literatury
The pathophysiological processes underlying the development of diabetic osteopenia has not hitherto been elucidated. Induction of streptozotocin diabetes leads in our experiments to decrease of bone density, ash, mineral content and to thinner cortical width compared to control male rats. In order to investigate the pathogenetic role of bone resorption by osteoclasts in streptozotocin-induced diabetes, we determined the circulating levels of tartrate-resistant acid phosphatase (TRAP), a biochemical marker for bone resorption. Plasma TRAP values in diabetic rats did not differ from their corresponding controls. Streptozotocin diabetes by itself did not have any effect on the weight of seminal vesicles which are highly testosterone-dependent. Low doses of nitric oxide cause bone resorption, but higher doses of NO inhibit bone resorbing activity. We examined the effect of L-NAME (inhibitor of nitric oxide production) after six weeks of administration to diabetic rats. There was no further significant loss of bone mineral density, ash and mineral content or tibia weight in diabetic rats treated with L-NAME. L-NAME itself did not decrease bone metabolism. In our study no evidence of an increased bone resorption was found. Our results have indicated that a predominance of bone resorption over bone formation is not involved in the pathogenesis of diabetes-associated osteopenia. Inhibition of NO neither increased osteoclastic activity (TRAP) nor induced osteopenia in L-NAME-treated rats. This suggests a possibility that NO is not involved in the pathogenesis of diabetic osteopenia., P. D. Broulík, M. Haluzík, J. Škrha., and Obsahuje bibliografii
We compared graft outcome between two types of a novel
composite three-layer carp-collagen-coated vascular graft in
low-flow conditions in a sheep model. Collagen in group A
underwent more cycles of purification than in group B in order to
increase the ratio between collagen and residual fat. The grafts
were implanted end-to-side in both carotid arteries in sheep
(14 grafts in 7 sheep in group A, 18 grafts in 9 sheep in group B)
and artificially stenosed on the right side. The flow in the grafts
in group A decreased from 297±118 ml/min to 158±159 ml/min
(p=0.041) after placement of the artificial stenosis in group A,
and from 330±164ml/min to 97±29 ml/min (p=0.0052) in
group B (p=0.27 between the groups). From the five surviving
animals in group A, both grafts occluded in one animal 3 and 14
days after implantation. In group B, from the six surviving
animals, only one graft on the left side remained patent
(p=0.0017). Histology showed degradation of the intimal layer in
the center with endothelization from the periphery in group A
and formation of thick fibrous intimal layer in group B. We
conclude that the ratio between collagen and lipid content in the
novel three-layer graft plays a critical role in its patency and
structural changes in vivo.
Toxoplasma gondii, a parasite infecting 20-60% of humans in various countries, influences the behaviour of infected animal and human hosts. Infected human subjects have changes in several of Cattell's and Cloninger's personality factors. Recently, three independent studies have shown that Rh-positive subjects are protected against the T. gondii-induced changes of reaction times and increased risk of traffic accidents. Here we searched for evidence of similar effects of RhD phenotype on toxoplasmosis- or aging-associated changes in the personality profile of about 302 blood donors. We found that Rh-positive and Rh-negative subjects responded differently to toxoplasmosis. In addition to the already known effects of toxoplasmosis on novelty seeking, self transcendence, superego strength and protension, we also found effects of RhD phenotype on ego strength, protension, and praxernia, as well as opposite effects of toxoplasmosis on ego strength, praxernia, ergic tension and cooperativeness in Rh-positive and Rh-negative subjects. Moreover, our results indicate that RhD phenotype might influence not only the effect of toxoplasmosis but also the effect of aging on specific personality traits.
Smoking is the most widespread substance dependence in the world. Nicotine and some other components of the cigarette smoke cause various endocrine imbalances, and have negative effects on pituitary, thyroid, adrenal, testicular and ovarian functions. Here, we examined studies that describe the influence of smoking and smoking cessation on the male and female reproductive systems. We also focused on studies providing an account of differences in cessation success rates between men and women. In men, the most common effects associated with smoking are erectile dysfunction and decreasing spermiogram quality. Several groups have studied the effects of cigarette smoking on testosterone levels in men. However, the results have been conflicting. In women, nicotine has an antiestrogen effect and increases the ratio of androgens to estrogens throughout life. Beside nicotine, other cigarette toxins also cause dysregulation of reproductive and hormonal system, and essentially influence the probability of a successful pregnancy not only in cases of assisted reproduction but also in healthy women. Tobacco addiction is one of the forms of addiction that are generally thought to be different for men and for women. Women are less successful than men in quitting smoking, and nicotine replacement therapy is less effective in female smokers. We also summarize recent studies that have indicated possible reasons., H. Jandíková, M. Dušková, L. Stárka., and Obsahuje bibliografii
The correct determination of material properties of construction materials from experiments is important not only during their development, but also during final verification. Specimens for testing mechanical properties of fiber-reinforced composites with a quasi-brittle matrix are usuall prepared by casting into a sutable mold. But they can be also prepared by cutting to desired shape from large body of material. The method of preparation may affect the measured values of material characteristics. In the case of sawed specimens, the fibers in surface layer are damaged, while in the case of casted specimens, fibers in surface layer tended to align with mold surface. The purpose of this article is to clarify the influence of these phenomena using numerical simulations. and Obsahuje seznam literatury
Recently it has been shown that vitamin D3 acting via its cognate receptor (VDR) regulates the growth, differentiation and function of female reproductive tissues including ovary. The aim of the study was to examine the effect of testosterone (T) and its antagonist 2-hydroxyflutamide (HF) on VDR protein expression and function in porcine ovarian follicles. Medium size antral follicles expressing great amount of androgen receptors and represent high steroidogenic activity were used in this research. After 6 h incubation of whole follicles with T, HF or T+HF, immunohistochemical analysis of VDR revealed its nuclear localization in granulosa and theca interna cells in control and experimental groups. The expression of VDR protein was shown as a band of 48 kDa. There were no significant differences between either experimental group and the control. T influenced the function of VDR through decreased formation of VDR/RXR (retinoid X receptor) complexes (P<0.05) in both granulosa and theca interna cells, but HF abolished this effect only in granulosa cells (P<0.05). These results suggest that androgens regulate the response of follicular cells to vitamin D3 in pigs ovary via regulation of VDR transcriptional activity., M. Herian, M. R. Luck, M. Grzesiak., and Obsahuje bibliografii