This article deals with numerical modelling of contaminant transport in a locality near Bzenec. From the 1970s to the 1990s, this locality was subjected to groundwater contamination by chlorohydrocarbons (PCE, TCE, DCE). The locality is known for its drinking water supplies, which serve for over 100 000 people. Since 1992 remediation of the locality has been in progress, with several breaks due to funding problems. Numerical modelling was used as a method for assessing the efficiency of remediation and for predicting the contaminant transport until the end of 2006. In order to model contaminant transport, a 3D groundwater flow model was first created, calibrated and verified in steady state. Then the transport model was built to simulate contaminant transport. The modelling of contaminant transport was solved by using several scenarios where the input values for the dispersion, sorption and decay parameters were verified using measured values of contaminant concentration in the region of interest. and Článek se zabývá numerickým modelováním šíření znečištění v blízkosti Bzence. V průběhu 70. až 90. let minulého století došlo v této lokalitě ke kontaminaci podzemní vody chlorovanými uhlovodíky (PCE, TCE, DCE). Tato lokalita je významným zdrojem pitné vody pro více než 100 000 obyvatel. Od roku 1992 probíhájí v lokalitě sanační práce, které byly z finančních důvodů několikrát přerušeny. Pro ověření účinnosti sanačních prací a pro predikci šíření znečištění do konce roku 2006 byla využita metoda numerického modelování. Aby bylo možné simulovat proces šíření znečištění, byl nejprve sestaven, zkalibrován a verifikován třírozměrný model proudění podzemní vody pro ustálený stav. Potom byl vytvořen transportní model. Transport kontaminantu byl modelován v několika scénářích, lišících se hodnotami parametrů disperze, sorpce a rozpadové konstanty. Hodnoty těchto parametrů byly verifikovány pomocí měřených koncentrací znečišťujících látek v oblasti.
The aim of this study was to investigate whether the inhibition of one of the endothelial receptor sites in the rat pulmonary artery (muscarinic, histaminergic, purinergic, a 2-adrenergic) affects the NO-mediated relaxation induced by the activation of the other type of receptors. Acetylcholine (ACh)-, histamine (Hist)-, adenosine (Ade)- , and clonidine (Clon)-induced endothelium-dependent relaxations were reduced by the administration of specific antagonists of muscarinic, H1-histaminergic, purinergic or a 2-adrenergic receptors, respectively. The inhibition of H1-histaminergic receptors by chlorphenyramine did not prevent ACh-induced relaxation. Similarly, the inhibition of muscarinic receptors by atropine did not prevent the relaxations to histamine, adenosine and clonidine. On the other hand, the relaxations induced by acetylcholine, histamine, adenosine or clonidine were regularly reduced by NO-synthase inhibitor NG-nitro-L-arginine methyl ester (10-4 mol/l). These results suggest that the inhibition of NO-synthase abolished arterial relaxations induced by all agonists. After inhibition of one type of the endothelial receptors, the NO-dependent relaxation could still be evoked by activation of one of the others., S. Kyselá, J. Török., and Obsahuje bibliografii
We exploited leaves of tobacco (Nicotiana tabacum L., cv. Wisconsin 38) with introduced chimeric construct consisting of SAG12 promoter fused with ipt gene for cytokinin synthesis and therefore prolonged life-span. As a control we used its wild type. In 12-week-old plants, the first leaves of control plants showed senescence symptoms at the time of sampling. Carotenoid content decreased with increasing leaf age both in control and in transgenic plants. On the other hand, the first leaves of transgenic plants demonstrated better antioxidant capacity represented by carotenoids compared to the leaves of control plants of the same age. They stayed still green at this age. and D. Procházková, D. Haisel, N. Wilhelmová.