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1022. A role for receptor-operated Ca2+ entry in human pulmonary artery smooth muscle cells in response to hypoxia
- Creator:
- Tang, C., To, W. K., Meng, F., Wang, Y., and Gu, Y.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, hypoxie, hypoxia, Hypoxic pulmonary vasoconstriction (HPV), hPASMC, Transient receptor potential channel (TRPC), AMP-activated kinase (AMPK), 14, and 612
- Language:
- English
- Description:
- 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
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1023. A role of the coefficient of the differential term in qualitative theory of half-linear equations
- Creator:
- Řehák, Pavel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- half-linear dynamic equation, time scale, transformation, comparison theorem, and oscillation criteria
- Language:
- English
- Description:
- The aim of this contribution is to study the role of the coefficient r in the qualitative theory of the equation (r(t)Φ(y ∆))∆+p(t)Φ(y σ ) = 0, where Φ(u) = |u| α−1 sgn u with α > 1. We discuss sign and smoothness conditions posed on r, (non)availability of some transformations, and mainly we show how the behavior of r, along with the behavior of the graininess of the time scale, affect some comparison results and (non)oscillation criteria. At the same time we provide a survey of recent results acquired by sophisticated modifications of the Riccati type technique, which are supplemented by some new observations.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1024. A RSM method for nonlinear probabilistic analysis of the reinforced concrete structure failure of a nuclear power plant - type VVER 440
- Creator:
- Králik, Juraj
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- nuclear power plant VVER, probabilistic safety analysis, concrete failure, RSM, and ANSYS
- Language:
- English
- Description:
- 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
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1025. A salt-tolerant cultivar of wheat maintains photosynthetic activity by suppressing sodium uptake
- Creator:
- Muranaka, S., Shimizu, K., and Kato, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, photochemical activity, photoinhibition, salt tolerance, and Triticum
- Language:
- Multiple languages
- Description:
- 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.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1026. A sample-time adjusted feedback for robust bounded output stabilization
- Creator:
- Ordaz, Patricio, Alazki, Hussain, and Poznyak, Alexander
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- sample-time data, attractive ellipsoid, state extimation, saturated control process, and flexible arm system
- Language:
- English
- Description:
- This paper deals with a bounded control design for a class of nonlinear systems where the mathematical model may be not explicitly given. This class of uncertain nonlinear systems governed by a system of ODE with quasi-Lipschitz right-hand side and containing external perturbations as well. The Attractive Ellipsoid Method (AEM) application permits to describe the class of nonlinear feedbacks (containing a nonlinear projection operator, a linear state estimator and a feedback matrix-gain) guaranteeing a boundedness of all possible trajectories around the origin. To fulfill this property some modification of AEM are introduced: basically, some sort of sample-time corrections of the feedback parameters are required. The optimization of feedback within this class of controllers is associated with the selection of the feedback parameters which provide the trajectory converges within an ellipsoid of a "minimal size". The effectiveness of the suggested approach is illustrated by its application to a flexible arm system).
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1027. A scalar Volterra derivative for the PoU-integral
- Creator:
- Marraffa, V.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Pettis integral, McShane integral, PoU integral, and Volterra derivativ
- Language:
- English
- Description:
- A weak form of the Henstock Lemma for the PoU-integrable functions is given. This allows to prove the existence of a scalar Volterra derivative for the PoU-integral. Also the PoU-integrable functions are characterized by means of Pettis integrability and a condition involving finite pseudopartitions.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1028. A scheme for the classification of micaceous minerals
- Creator:
- Karel Melka
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, jílové minerály, clay minerals, macrocrystalline micas, IS ordered structures, ISII ordered structures, fundamental particles, 7, and 551
- Language:
- English
- Description:
- 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
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1029. A search for possible members of open clusters among known Ap stars
- Creator:
- Zelwanova, E. and Popova, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- astrophysics, open clusters, and investigation of Ap stars
- Language:
- Czech
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1030. A search of tidal interaction in the binary system λ And
- Creator:
- Głębocki, R., Bielicz, E., Pastuszka, Z., and Sikorski, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- astrophysics, tidal interaction, and binary system λ And
- Language:
- Czech
- Description:
- 31 UV spectra obtained with tne LWR camera of the lUE satellite in the period 1978-83 were analysed. Changes of Mg II h and k emissions are evident but there is no evident correlation between emission intensity of Mg II and orbital or photometric phase. Using three various methods of analysis of possible periodicity in variation of Mg II h and k emission intensities we have found reál chanes in h + k fluxes with period equal to the half of the orbital one, 0.5 Porb = 10.2606. We interpret this effect as evidence of direct influence of tidal inxeraction of secondary component on the chromospheric structure of the primary. Evident minimum of the Mg II h and k intensity is observed when the tides are on the line of sight and maximum when both tidal bulges are visible. Difference between maximum and minimum of total flux of k line is equal to about 20%, while the shape of the profile is practically unchanged.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public