Hypoxic pulmonary vasoconstric tion (HPV) is an important homeostatic mechanism in which increases of [Ca2+] i are primary events. In this study, primary cultured, human pulmonary artery smooth muscle cells (hPASMC) were used to examine the role of TRPC channels in mediating [Ca2+] i elevations during hypoxia. Hypoxia (PO2 about 20 mm Hg) evoked a transient [Ca2+] i elevation that was reduced by removal of extracellular calcium. Nifedipine and verapamil, blockers of vo ltage-gated calcium channels (VGCCs), attenuated th e hypoxia-induced [Ca2+] i elevation by about 30 %, suggesting the presence of alternate Ca2+ entry pathways. Expression of TRPC1 an d TRPC6 in hPASMC were found by RT-PCR and confirmed by Western blot analysis. Antagonists for TRPC, 2APB and SKF96365, significantly reduced hypoxia-induced [Ca2+] i elevation by almost 60 %. Both TRPC6 and TRPC1 were knocked down by siRNA, the loss of TRPC6 decreased hypoxic response down to 21 % of control, whereas the knockdown of TRPC1 reduced the hypoxia respon se to 85 %, suggesting that TRPC6 might play a central role in mediating hypoxia response in hPASMC. However, blockade of PLC pathway caused only small inhibition of the hypoxia response. In contrast, AICAR, the agonist of AMP-activated kinase (AMPK), induced a gradual [Ca2+] i elevation, whereas compound C, an antagonist of AMPK, almost abolished the hypoxia response. Ho wever, co-immunoprecipitation revealed that AMPK α was not colocalized with TRPC6. Our data supports a role for TRPC6 in mediation of the [Ca2+] i elevation in response to hypoxia in hPASMC and suggests that this response may be linked to cellular energy status via an activation of AMPK., C. Tang, W. K To, F. Meng, Y. Wang, Y. Gu., and Obsahuje bibliografii
This paper describes the reliability analysis of a concrete containment for VVER 440 under a high internal overpressure. The probabilistic safety assessment (PSA) level 3 aims at an assessment of the probability of the concrete structure failure under the excessive overpressure. The non-linear analysis of the concrete structure was considered. The uncertainties of the loads level (long-time temperature and dead loads), the material model (concrete cracking and crushing, behavior of the reinforcement and liner), degradation effects and other influences following from the inaccuracy of the calculated model and numerical methods were taken into account in the response surface method (RSM). The results of the reliability analysis of the NPP structues are presented. and Obsahuje seznam literatury
The effects of NaCl treatment on the photosynthetic machinery in wheat (Triticum aestivum L.) cultivars differing in salt tolerance were investigated by comparison with iso-osmotic PEG treatment. Both cultivars similarly reduced the photosystem 2 (PS2) energy conversion efficiency (ΦPS2) rapidly when plants were exposed to a 100 mM NaCl solution, though no decline was detected under the iso-osmotic PEG treatment. There was no correlation between the reduction of the leaf relative water content (RWC) and the ΦPS2 in the two iso-osmotic stress treatments. In contrast, a decline of ΦPS2 along with the increase of the leaf sodium content above 4 % dry matter was detected under the NaCl treatment, while no such correlation was detected with other cations. The recovery of ΦPS2 after photoinhibitory irradiation was repressed by the NaCl treatment as the increase of the duration of the treatment. Norin 61 subjected to the 100 mM NaCl treatment for 10 d showed a decline of the ΦPS2 after 1 h moderate irradiation of 400 μmol m-2 s-1 PPFD. Thus the concentrated Na+ within a leaf under salinity treatments may decrease the stability of PS2 functions and lead to photochemical inactivation. and S. Muranaka, K. Shimizu, M. Kato.
The classification scheme for micaceous minerals is described. According to the size of mineral particles micas are divided into macrocrystalline compounds and microcrystalline clay micas. Macroc rystalline micas are differentiated into (a) Mg-Fe-Al micas, (b) Li-micas, (c) micas with other cations. Vertical boundary in the suggested scheme divides micas into trioctahedral and dioctahedral members. Additional subdivision is carried out on the basis of the extent of Si substitution in tetrahedral positions of their crystal lattice. Microcrystalline (<4μm) micas are subordinate to the crystallochemical scheme for macrocrystalline micas. List of mica species together with their varieties and synonyms is in Table 2., Karel Melka., and Obsahuje bibliografické odkazy
Measurement of leaf area is commonly used in many horticultural research experiments, but it is generally destructive, requiring leaves to be removed for measurement. Determining the individual leaf area (LA) of bedding plants like pot marigold (Calendula officinalis L.), dahlia (Dahlia pinnata), sweet William (Dianthus barbatus L.), geranium (Pelargonium × hortorum), petunia (Petunia × hybrida), and pansy (Viola wittrockiana) involves measurements of leaf parameters such as length (L) and width (W) or some combinations of these parameters. Two experiments were carried out during spring 2010 (on two pot marigold, four dahlia, three sweet William, four geranium, three petunia, and three pansy cultivars) and summer 2010 (on one cultivar per species) under greenhouse conditions to test whether a model could be developed to estimate LA of bedding plants across cultivars. Regression analysis of LA versus L and W revealed several models that could be used for estimating the area of individual bedding plants leaves. A linear model having LW as the independent variable provided the most accurate estimate (highest R2, smallest mean square error, and the smallest predicted residual error sum of squares) of LA in all bedding plants. Validation of the model having LW of leaves measured in the summer 2010 experiment coming from other cultivars of bedding plants showed that the correlation between calculated and measured bedding plants leaf areas was very high. Therefore, these allometric models could be considered simple and useful tools in many experimental comparisons without the use of any expensive instruments. and F. Giuffrida ... [et al.].
The paper deals with the rotor vibration in journal bearings to prepare a model for verifying the rotor vibration active control. The rotor is maintained in equilibrium position by forces generated in oil film. Bearing forces can be modelled as a spring and damper system. The main goal of the simulation study is to verify the model principle and to estimate parameters by comparing simulation results with experimental data, namely the instability of motion. Test stand with rotor supported in two journal bearings was designed for these purposes. The stand will be equipped with four piezoactuators enabling excitation of bearings by practically arbitrary dynamic force. Theoretical analysis of the influence of external excitation on rotor behaviour was carried out. Up to now the study shows that simple kinematic excitation is effective for reducing rotor excursion while passing critical speeds. To suppress self-exciting vibration of the rotor it is necessary to look for more sophisticated solution. and Obsahuje seznam literatury
Over the past 40 years, much has been published on the ultrastructure and cellular development of embryonic structures in a wide range of cestodes. However, the literature contains many discrepancies in both terminology and interpretations because of the facts that these organisms are phylogenetically diverse within their respective orders and families, the habitats that affect embryonic envelope structure are diverse, and the work has been done in various laboratories around the world. This review and synthesis was initiated by a working group of biologists from around the world convened at the Fifth International Workshop on Cestode Systematics and Phylogeny in České Budĕjovice, at the Institute of Parasitology of the Biology Centre, Academy of Sciences of the Czech Republic. It brings together the data from published work and establishes a uniform terminology and interpretation based on the data as they are presented. A consensus was reached for standardised definitions of the oncosphere, hexacanth, coracidium, embryonic envelopes, outer envelope, inner envelope, embryophore, vitelline capsule, shell, and outer coat. All of these are defined as components of the embryo or its vitellocyte-derived or uterine-derived coatings.