Autor popisuje různé metody umožňující studium půdní fauny a flóry – edafonu. Vedle studia pomocí skenovacího elektronového mikroskopu (SEM) se uplatňuje hlavně metoda tzv. půdních výbrusů. and The author describes various techniques for studying soil fauna and flora. In addition to the scanning electron microscope (SEM), soil microsection techniques are primarily applied.
Using aluminum films combined with protective dielectric film is amethod of choice for many reflective applications in the visible (VIS) and the near infrared (NIR) range. An optical defect occurred during the introduction of the deposition aluminum (Al) films protected by a silicon dioxide (SiO2 ) protective film in our laboratory. Both films were deposited using an electron beam evaporator. S iO2 layers were deposited using the ion beam assisted deposition (IBAD). The results were not satisfactory. Produced films were matting and struggled with a significant reflectance decrease. The article presents an experimental approach which has been performed in order to eliminate the matting effect and the reflectance decrease. and Hliníková vrstva v kombinaci s ochrannou dielektrickou vrstvou je jedna z nejčastěji používaných možností pro výrobu reflexních prvků v oblasti viditelného a blízkého infračerveného světla. Při depozici těchto vrstev v naší laboratoři byl pozorován problém s degradací kvality ve formě viditelného zašednutí a výrazné ztráty reflektance. Hliníková i dielektrické vrstvy jsou nanášeny vakuovým odpařováním z elektronového děla. V případě dielektrické vrstvy je pak použita varianta zvaná IBAD (Ion Beam Assisted Deposition). Článek představuje výsledky experimentů, kterými byl nalezen optimální procesní postup eliminující degradaci optické kvality deponovaných vrstev.
Water-borne transmission of the coccidium Cryptosporidium parvum Tyzzer, 1912 is frequently responsible for outbreaks of human cryptosporidiosis. One of the most important was reported in 1993 in Milwaukee in the United States, where 403,000 cases were recorded. The determination of the percentage of oocysts excystated is the first step in evaluating their viability, but it alone is not sufficient. This percentage depended on the conditions of storage and also the presence of oxidant or disinfectent agents in water. The percentage of excystation is not always related to viability. Therefore, determination of the viability of excysted sporozoites by determining their infectivity for enterocytic Caco2 cell lines in culture provides information essential for evaluating the risk of contaminated drinking water.
This is a followup report on the viability of pathogenic Acanthamoeba castellami, Naegleria australiensis, and N. fowleri during 5 years of cryopreservation and the virulence of N. fowleri during 30 months of cryostorage, all at -70’C. The greatest decrease in viability occurred during the first year of freezing and was 10-fold greater than the average yearly decrease during years 2-5. At 5 years of cryostorage, viability was 33 % for A. castellana, 38 % for N. fowleri and 51% for N. australiensis. Virulence of N. fowleri did not decrease during 30 months of freezing and what appeared to be an increase in virulence during cryopreservation may be the result of reduced viability of the less virulent amebae in a culture.
This is a follow-up report on the viability of pathogenic Naegleria fowleri, Naegleria australiensis and Acanthamoeba castellanii isolates during 5 to 10 years of cryopreservation at –70°C. The greatest decrease in viability occurred with N. fowleri and the least occurred with N. australiensis. At 10 years of cryostorage, viability was 21% for N. fowleri, 32% for A. castellanii and 51% for N. australiensis.
The influence of water environment on natural frequencies of a Francis pump-turbine runner with the shaft is analyzed. The computations are executed by ANSYS program package based on finite element method. The fluid ‘equivalent mass‘ matrix concept is used. For solution, the Euler approach is used. Obtained natural frequencies and vibration mode shapes of the turbine runner with shaft in vaccum, in air and in water are presented. Computed natural frequencies and vibration mode shapes of the turbine runner with shaft in vacuum are compared to computed natural frequencies and vibration mode shapes of the turbine runner without shaft. and Obsahuje seznam literatury