electron diffraction
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Practical methods in electron microscopy ; Vol. 12
XVI, 287 s. : il. ; 24 cm
Autoři vyšetřili vzorky epimakulární tkáně u klinicky signifikatního makulárního edému transmisní elektronovou mikroskopií. Nenalezli morfologické rozdíly vzorků získaných od nemocných ošetřených laserovou koagulací před pars plana vitrektomií od těch, u kterých laserová léčba nebyla použitá. Nálezy lze rozdělit do tří skupin: ILM, která je krytá kolagenními sklivcovými vlákny, buněčné elementy typu fibroblastů a fibrózních astrocytů v kortexu sklivce tvořící jedno či vícevrstevné buněčné membrány.
The authors examined samples of the epimacular tissue in clinically significant macular edema by means of the transmissing electron microscopy. They did not found morphological differences between samples from patients already treated by means of laser photocoagulation before the pars plana vitrectomy and those without the laser treatment. Findings may be divided into three groups: (1) the inner limiting membrane (ILM) covered with collagen vitreous fibers, (2) cells’ elements of the fibroblasts category, and (3) fibrous astrocytes in the vitreous cortex constituting one- or multilayer cellular membranes.
Leachates collected at two (active and closed) municipal solid waste (MSW) landfills were examined for colloids and particles by transmission electron microscopy, energy dispersive spectrometry, selected area electron diffraction and for the chemical compositions of the filtrates after the filtration to 0.1 µm and ultrafiltration to 1 kDa (~ 1 nm). Six groups of colloids/particles in the range 5 nm to 5 µm were determined (in decreasing order of abundance): carbonates, phyllosilicates (clay minerals and micas), quartz, Fe-oxides, organics and others (salts, phosphates). Inorganic colloids/particles in leachates from the active landfill predominantly consist of calcite (CaCO(3)) and minor clay minerals and quartz (SiO(2)). The colloids/particles in the leachates from the closed landfill consist of all the observed groups with dominant phyllosilicates. Whereas calcite, Fe-oxides and phosphates can precipitate directly from the leachates, phyllosilicates and quartz are more probably either derived from the waste or formed by erosion of the geological environment of the landfill. Low amounts of organic colloids/particles were observed, indicating the predominance of organic molecules in the 'truly dissolved' fraction (fulvic compounds). Especially newly formed calcite colloids forming particles of 500 nm and stacking in larger aggregates can bind trace inorganic contaminants (metals/metalloids) and immobilize them in landfill environments.
... The basic principles of the electron microscope 1 -- 1.1 The use of electrons for microscopy 2 -- 1.2 ... ... Electron lenses 4 -- 1.3 Defects of electron lenses 9 -- 1.3.1 Spherical aberration 9 -- 1.3.2 Chromatic ... ... The design of the electron microscope 38 -- 2.1 General construction of the column 38 -- 2.2 The electron ... ... microscope 110 -- 3.10.1 Electron diffraction 110 -- 3.10.2 High dispersion electron diffraction 112 ... ... 313 -- 9.3.3 Energy analysis 316 -- 9.3.4 Scanning electron diffraction 319 -- 9.4 Scanning transmission ...
Practical methods in electron microscopy ; v. 2
Laboratory edition xii, 345 stran : ilustrace ; 23 cm
- MeSH
- elektronová mikroskopie MeSH
- fyzika MeSH
- mikroskopie MeSH
- Publikační typ
- monografie MeSH
- Konspekt
- Fyzika
- NLK Obory
- fyzika, biofyzika
This study was conducted to investigate Brachymystax lenok tsinlingensis spermatozoa cell morphology and ultrastructure through scanning and transmission electron microscopy. Findings revealed that the spermatozoa can be differentiated into three major parts: a spherical head without an acrosome, a short mid-piece, and a long, cylindrical flagellum. The mean length of the spermatozoa was 36.11±2.84μm, with a spherical head length of 2.78±0.31μm. The mean anterior and posterior head widths were 2.20±0.42μm and 2.55±0.53μm, respectively. The nuclear fossa was positioned at the base of the nucleus that contained the anterior portion of flagellum and a centriolar complex (proximal and distal centrioles). The short mid-piece was located laterally to the nucleus and possessed just one spherical mitochondrion with a mean diameter of 0.65±0.14μm. The spermatozoa flagellum was long and cylindrical, and could be separated into two parts: a long main-piece and a short end-piece. The main piece of the flagellum had short irregular side-fins. The axoneme composed the typical '9+2' microtubular doublet structure and was enclosed by the cell membran e. This study confirmed that B. lenok tsinlingensis spermatozoa can be categorized as teleostean "Type I" spermatozoa; 'primitive' or 'ect-aquasperm type' spermatozoa. To the best of the authers knowledge, this was the first study conducted on the morphology and ultrastructure of B. lenok tsinlingensis spermatozoa.
- MeSH
- akrozom ultrastruktura MeSH
- axonema ultrastruktura MeSH
- buněčné jádro ultrastruktura MeSH
- centrioly ultrastruktura MeSH
- flagella ultrastruktura MeSH
- mikroskopie elektronová rastrovací MeSH
- mitochondrie ultrastruktura MeSH
- Salmonidae anatomie a histologie růst a vývoj MeSH
- spermie ultrastruktura MeSH
- transmisní elektronová mikroskopie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Na přelomu května a června 2015 propukla v některých oblastech městské části Praha 6 epidemie gastroenteritidy. V průběhu epidemie vyhledalo lékařské ošetření 5150 osob. S odhadovaným celkovým počtem případů onemocnění 11 000 se jedná o dosud největší epidemii v ČR, kde byla jako zdroj infekce identifikována kontaminovaná voda. Klíčovou roli v objasnění etiologie této epidemie sehrála transmisní elektronová mikroskopie. Vyšetřením elektronovou mikroskopií byly ve vzorcích pitné vody, jakož i v klinických vzorcích pacientů (zvratky a stolice) ze zasažené oblasti odhaleny noroviry jako hlavní etiologické agens. V některých vzorcích stolic byly prokázány i rotaviry. Elektronmikroskopické vyšetření vzorků dříve vyšetřených imunochromatografickými testy poukázalo na nedostatečnou sensitivitu těchto testů. Elektronová mikroskopie byla využita i pro následnou kontrolu účinnosti hygienických opatření, po jejichž provedení již noroviry nebyly ve vodovodní vodě prokázány.
A community water-borne gastroenteritis outbreak occurred in some areas of the district Prague 6 in May/June 2015. During the outbreak, 5110 persons sought medical attention. With the estimated 11,000 cases, the outbreak was the largest ever linked to contaminated drinking water in the Czech Republic. Transmission electron microscopy played the key role in the clarification of the etiology of this outbreak. Electron microscopy detected noroviruses from both drinking water samples and patient clinical specimens (stool and vomits) as the main cause of the outbreak. In some stool samples, rotaviruses were also found. Electron microscopy of samples previously screened by immunochromatographic tests revealed that the tests used were not sensitive enough. Electron microscopy was also helpful in checking the efficacy of the public health measures implemented: noroviruses were no longer detected in the water supply system.
Scanning and transmission electron microscopy (TEM) were used to study the histopathological effects of the monogenean Macrogyrodactylus clarii Gussev, 1961 on the gills of the catfish Clarias gariepinus (Burchell). Suction generated during attachment created 'footprints' on host surfaces in which the host tissues were elevated above the general gill surface. 'Footprints' were bordered by four clefts caused by the muscular flaps on the anterior, lateral and posterior margins of the haptor. The hamuli points penetrate the gill tissue but no evidence was found for the insertion of the marginal hooklets. At the site of attachment, host cells adjacent to the lateral flaps often appeared compressed and widely spaced with large intercellular spaces. Desquamation of these surface epithelia was also apparent and some of the widely spaced epithelial cells had pseudopodium-like processes. Cells within the upper surface epithelial layer of the host were vacuolated and necrotic. Ruptured blood capillaries (blood spaces) in the secondary gill lamellae contained atypical compressed erythrocytes, agranular and granular leucocytes and evidence of haemorrhaging. Cells with fibrotic cytoplasm, putative phagocytes and host mucous cells were evidence of a host response at the site of parasite attachment. The possible role of these cells is discussed in relation to host resistance against infection.
- MeSH
- infekce červy třídy Trematoda parazitologie patologie MeSH
- mikroskopie elektronová rastrovací MeSH
- nemoci ryb parazitologie patologie MeSH
- sumci parazitologie MeSH
- transmisní elektronová mikroskopie MeSH
- Trematoda ultrastruktura MeSH
- žábry patologie ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVES: The exact etiology of scoliosis is still unknown. The main purpose of this study is to search for the possible causation of scoliosis in the development changes of autonomic nervous structures. In this prospective study, we followed-up the changes in peripheral nerve structures and its discrepancies regarding the concavity and convexity of the scoliotic curve. MATERIALS AND METHODS: We evaluated 12 patients with the idiopathic scoliotic deformity and the control group of 3 patients without any scoliotic deformity. The samples from the peripheral nerves of the convexity and concavity of the scoliotic deformity were drawn during the surgical correction by using the transthoracic approach. The samples were examined by the electron microscopic method and morphometric statistical evaluation. RESULTS: In samples taken from the scoliotic convexity, 23.71% of myelinized nerve fibers (MNF), 12.21% of unmyelinized nerve fibers (UNF), and 5.0% of Schwann cells (SC) were found by the morphometric measurement. There were 17.36% of MNF, 5.82% of UNF, and 5.27% of SC in samples taken from the concavity and 29.9% of MNF, 19.9% of UNF, and 16.7% of SC in the control nonscoliotic samples. Statistically significant differences between both sides of scoliotic deformity (convexity and concavity) and differences between the scoliotic samples and the nonscoliotic control samples were found. In all scoliotic samples, significant morphologic changes were found, mostly in the myelin sheaths and axon fiber abnormalities compression. CONCLUSION: There are significant morphologic changes in spinal autonomic nervous structures in scoliotic patients. These findings can help us in the search for the etiology of scoliosis
Spermatozoon formation in Caryophyllaeides fennica (Schneider, 1902) is characterised by the following: (1) apical electron-dense material in the zone of differentiation, (2) typical striated roots situated unconventionally in opposite directions in early stages of spermiogenesis, (3) intercentriolar body composed of three electron-dense and two electron-lucent plates, (4) free flagellum and a flagellar bud that correspond to a greatly reduced flagellum and (5) rotation of free flagellum and a flagellar bud to the median cytoplasmic process at 90°. The development of two flagella of significantly unequal length clearly supports a derived form of spermiogenesis in the Caryophyllidea. New for cestodes is a finding of two additional striated roots situated opposite each other, in conjunction with both the flagellar bud and free flagellum. Mutual position of additional striated roots and typical striated roots is parallel in early stages and perpendicular in advanced stages of spermiogenesis. A complete proximodistal fusion gives rise to a mature spermatozoon consisting of one axoneme, parallel cortical microtubules, a nucleus and a moderately electron-dense cytoplasm with glycogen particles, detected by a technique of Thiéry (J Microsc 6:987-1018, 1967), in the principal regions (II, III, IV). Electron tomography analysis of the free flagellum and one axoneme of a mature spermatozoon of C. fennica provides clear evidence, for the first time, that two tubular structures are present in the central axonemal electron-dense core. Phylogenetically important aspects of spermiogenesis of the Caryophyllidea with one axoneme, and other cestodes with one or two axonemes, are briefly reviewed and discussed.
- MeSH
- axonema ultrastruktura MeSH
- buněčné jádro ultrastruktura MeSH
- Cestoda ultrastruktura MeSH
- cestodózy MeSH
- flagella ultrastruktura MeSH
- mikrotubuly ultrastruktura MeSH
- spermatogeneze fyziologie MeSH
- spermie ultrastruktura MeSH
- tomografie elektronová MeSH
- transmisní elektronová mikroskopie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
