Shown an approach to the calculation of anisotropic plates numerically-analytical boundary elements method. The two-dimensional problem is reduced to one-dimensional by variation method Kantorovich-Vlasov. To select a function of the transverse distribution of deflecitons are encouraged to use one of two methods - dynamic or static. Application of numerical and analytical boundary element method allows a single approach to obtain the solution of basic differential equation of bending of anisotropic plate with any boundary conditions and without any restrictions on the nature of the application of the external load. and Obsahuje seznam literatury
Physiological parameters were measured after experimental infection of roach (Rutilus rutilus L.) with Rhipidocotyle fennica Gibson, Valtonen et Taskinen, 1992 (Digenea) cercariae. The fish were caught from two lakes: a eutrophic bleached kraft mill effluent (BKME)-contaminated lake and an oligotrophic unpolluted lake. The intensity of infection was followed up to 10 days post infection (p.i.) and physiological parameters indicating non-specific stress responses and the condition of fish were examined simultaneously. The mean abundance, the number of parasites per fish, of R. fennica was significantly higher in the fish from the contaminated water during the first two days p.i., probably reflecting the decreased resistance of these fish to infection. The decrease of leukocrit, as well as the increase of the activity of transaminases (GOT and GPT) in infected fish of both groups are suggestive of pathological processes caused by cercariae penetrating the fish. A significantly lower leukocrit value, as well as higher alkaline phosphatase activity and plasma chloride levels were noted in fish originating from the contaminated lake compared to those from the unpolluted lake. No significant differences were noted in haematocrit, plasma protein and calcium values between the fish from the uncontaminated and contaminated lakes, or between the infected and uninfected control fish.
Malate dehydrogenase (EC 1.1,1,37.) (MDH) was purified to apparent homogeneity from the cytosolic fraction of the protozoan Trichomonas vaginalis Donné. The four step purification included ion-exchange chromatography (DEAE-Sephacel and Q-Sepharose, elution with NaCl) and affinity chromatography (Reactive Red Agarose, elution with NADH and NaCl). The enzyme was purified about 132-fold (30.6% yield) to a specific activity of 352 units mg~'. The Km values determined at pH 7.8 (pH optimum from 7.5 to 8.3) for oxaloacetate and NADH were 16.2 pM and 10.6 μΜ, respectively. The MDH activity was inhibited by the substrate, decreasing to 50% at about 1 mM concentration of oxaloacetate. The reverse reaction from malate to oxaloacetate showed a pH optimum around pH 9.5. The Km for malate and NAD* (determined at pH 7.8) were 1220 pM and 69.9 pM, respectively. SDS-PAGE analysis of the purified MDH revealed a single band with an apparent size of 34.5 kDa. The native molecular weight was estimated by HPLC gel filtration to be 60 kDa, which indicates that the T. vaginalis MDH exists as a dimer.
Intact cells of Synechococcus elongatus were treated with different concentrations (0.1 and 1.0 mM = Cd0.1, Cd1.0) of CdCl2 for 24 h. Cd0.1 treatment stimulated growth of the cell culture and chlorophyll (Chl) a concentration in the culture. Cd1.0 inhibited both the above mentioned parameters. The oxygen evolving activity of intact cells (H2O → BQ) as well as of isolated thylakoid membranes, TM (H2O → DCPIP; H2O → PBQ + FeCy) decreased after 24 h of Cd1.0 cultivation to 7 %. Photosystem 1 (PS1) activity was less sensitive to the effect of Cd2+ than PS2 activity. CdCl2 concentration in cultivation media after 24 h of cultivation proved that the cyanobacterium cells take up these ions to a large extent from the cultivation medium. After 24 h of the Cd1.0 treatment only 12 % of the amount of Cd2+ originally added to the cultivation medium was found. The ratio of external-antenna pigments, phycocyanin, and allophycocyanin to Chl increased approximately twofold with growing Cd2+ concentration in the cultivation medium. This ratio was found in both TM and dodecylmaltoside extracts. and E. Tůmová, D. Sofrová.
Sulfite, at concentrations from 0.05 to 5.0 mM, inhibited the uptake of sucrose into stripped tissue disks and enzymatically isolated vein networks from mature pea leaves. Sulfite affected the rate of sucrose uptake, while the value was not influenced. The isolated vein networks were much more sensitive to sulfite action than stripped leaf disks.