The paper deals with the tire microstructures - microareas of the adhesive interfaces of steel cord - rubber. Namely attention is dedicated to degraded adhesive interfaces upon corrosion failure. The optical microscope is used for microscopy study of surfaces in the area of the adhesive interfaces of metal - rubber. Knowledge about degradation processes into microareas of the adhesive interfaces is important for process study of ultimate states of wear. Also knowledge about characteristic behaviour is possible to use in creation of complex computational models of tires. and Příspěvek se zabývá mikrooblastí adhezních vazeb ocelový výztužný kord - elastomer v pneumatikách z pohledu mikrostruktury. Pozornost je věnována zejména porušeným adhezním vazbám. Pro mikroskopické zkoumání adhezních vazeb kov - pryž je použit světelný mikroskop. Poznatky o iniciaci porušování adhezních vazeb jsou důležité pro studium procesu mezního stavu opotřebení. Znalosti o charakteristickém chování adhezních vazeb a změn materiálových struktur lze uplatnit při tvorbě komplexních výpočtových modelů pneumatik.
V elektronových prozařovacích mikroskopech pro studium biologických objektů nebo polymerových struktur se standardně používají elektrony s energií kolem 100 keV. Pozorované tenké vzorky v nich mají velmi nízký kontrast, proto musí být konstrastovány těžkými kovy. Tento postup však může přinést množství artefaktů, neboť v tomto případě již nepozorujeme samotný vzorek, ale těžké atomy, které obklopují struktury ve vzorku a tím je zvýrazňují. Pro mnohé aplikace tato metoda dává dobré výsledky, avšak s rostoucími nároky na zkoumané objekty, například při studiu kompozitních materiálů, je vhodné pozorovat tyto objekty v co nejméně pozměněném stavu., Petr Štěpán., and Obsahuje seznam literatury
Parasites of the genus Cryptosporidium Tyzzer, 1910 are one of the most common protistan parasites of vertebrates. Faecal samples from 179 red foxes (Vulpes vulpes [Linnaeus]), 100 grey wolves (Canis lupus Linnaeus), 11 golden jackals (Canis aureus Linnaeus), and 63 brown bears (Ursus arctos Linnaeus) were collected in the Czech Republic, Poland and Slovakia. Samples were examined for the presence of Cryptosporidium spp. using microscopy and PCR/sequence analysis. Phylogenetic analysis based on the small subunit ribosomal RNA (SSU), actin and 60-kDa glycoprotein (gp60) genes using the maximum likelihood method revealed the presence of Cryptosporidium tyzzeri Ren, Zhao, Zhang, Ning, Jian et al., 2012 (n = 1) and C. andersoni Lindsay, Upton, Owens, Morgan, Mead et Blackburn, 2000 (n = 2) in red foxes, C. canis Fayer, Trout, Xiao, Morgan, Lai et Dubey, 2001 (n = 2) and C. ubiquitum Fayer, Santín et Macarisin, 2010 (n = 2) in grey wolves, and C. galli Pavlásek, 1999 in brown bears (n = 1) and red foxes (n = 1). Subtyping of isolates of C. ubiquitum and C. tyzzeri based on sequence analysis of gp60 showed that they belong to the XIId and IXa families, respectively. The presence of specific DNA of C. tyzzeri, C. andersoni and C. galli, which primarily infect the prey of carnivores, is probably the result of their passage through the gastrointestinal tract of the carnivores. Finding C. ubiquitum XIId in wolves may mean broadening the host spectrum of this subtype, but it remains possible this is the result of infected prey passing through the wolf - in this case deer, which is a common host of this parasite. The dog genotype of C. canis was reported for the first time in wolves.
The progressive decline in cotton leaf photosynthesis with season could be accounted for by gaining an insight into ontogenic changes in chloroplast integrity and epicuticular wax ultrastructure. Therefore, the sequence of ultrastructural changes in chloroplast and epicuticular wax morphology were probed in 10-, 20-, 40-, and 60-d-old cotton (Gossypium hirsutum L.) leaves using electron microscopy. Scanning electron microscopy illustrated that the epicuticular wax on the periclinal walls of the convex epidermal cells occurred as striations and persisted as such during the course of leaf aging. The degree of wax spread, however, increased as the leaf progressed towards senescence. Transmission electron microscopy revealed that a 20-d-old photosynthetically active leaf possessed healthy chloroplasts (6.8 μm long and an area of 9.7 μm2) with absolute membrane integrity depicted by large appressed grana stacks of thylakoids interconnected by non-appressed stroma lamellae. The thylakoid membrane network was oriented parallel to the long axis of the chloroplast and a few small plastoglobuli (1.85 μm2) scattered in the stroma. Conversely, membrane integrity was lost with leaf age after 20 d as evidenced by disruption of the grana and stroma lamellae. Concurrent with the membrane damage, extensive occlusion of chloroplast by several large spherical plastoglobuli (5.68 μm2) occurred, the rate of occlusion increased with leafage distending the chloroplast as evidenced by proliferation of its cross-sectional area (12.8 μm2). Of particular interest was the finding that the plastoglobuli ensued through the chloroplast envelope into the cytoplasm. The progressive loss of chloroplast membrane integrity coupled with increased leaf waxiness may have limited photosynthetic activities of cotton leaves during senescence. and B. R. Bondada, D. M. Oosterhuis.
Tato studie se věnuje rané fázi mikroskopického zkoumání přírody Antoni van Leeuwenhoeka (1632-1723), které představil ve své korespondenci členům Royal Society. Studie se zaměřuje na období od navázání styku s Royal Society (1673) až do roku 1680, kdy byl Leeuwenhoek zvolen členem společnosti. Z metodologického hlediska studie uplatňuje na Leeuwenhoekovy dopisy členům Royal Society přístup, který představili autoři Steven Shapin a Simon Schaffer v knize Leviathan and the Air-Pump (1985). Pokouší se zjistit, jestli se v Leeuwenhoekových dopisech objevují tři strategie, (materiální, literární a sociální), které Shapin a Schaffer přisoudili Robertu Boylovi. Studie potvrzuje, že závěry britských autorů platí i pro jiné vědce., The aim of the study is to discuss the early microscopic examination of nature, introduced by Antoni van Leeuwenhoek (1632-1723) in his letters to the Royal Society. The paper focuses on period from the establishing of contact with the Royal Society (1673) to the electing of Leeuwenhoek the member of the Society in 1680. From the methodological point of view the study uses the approach which Steven Shapin a Simon Schaffer presented in their book Leviathan and the Air-Pump (1985). The study tries to find out to what extent it is possible to understand Leeuwenhoek's letters as expressing three technologies (material, literary, and social) proposed by the British authors. The paper shows that the Shapin's and Schaffer's understanding of experimental science of Robert Boyle is transferrable to other scientists., and Monika Špeldová.
V referátu přinášíme shrnutí některých našich výsledků z oblasti studia růstu atomárních struktur kombinací experimentálního a teoretického přístupu. Řádkovací tunelová mikroskopie (STM) nám poskytuje atomárně rozlišenou informaci v reálném prostoru, která umožňuje navržení modelu růstu, jenž je dále rozvíjen pomocí kinetických Monte Carlo (KMC) simulací., We briefly summarize our results concerning the field of growth of atomic structures, using a combination of experimental and theoretical approaches. Scanning tunnelling microscopy (STM) provides atomically resolved information in real space allowing us to propose growth models, which can be further developed using kinetic Monte Carlo (KMC) simulations., Pavel Kocán, Pavel Sobotík, Ivan Ošťádal., and Obsahuje bibliografii