Electron-Microscopic Aspect of Pancreatic Fibrosis: Pancreatic Periacinar Collagenization at the Initial Stage

2007 ◽  
pp. 80-93
Author(s):  
Junji Kuroda ◽  
Koichi Suda ◽  
Yoshinori Hosokawa
Keyword(s):  
Pancreatic Fibrosis ◽  
Electron Microscopic ◽  
Initial Stage ◽  
Microscopic Aspect

scholarly journals Effect of orientation of initially formed grains on the final morphology of electrodeposited lead

2014 ◽  
Vol 79 (8) ◽  
pp. 993-1005 ◽  
Author(s):  
Nebojsa Nikolic ◽  
Konstantin Popov ◽  
Evica Ivanovic ◽  
Goran Brankovic
Keyword(s):  
Growth Process ◽  
Sem Analysis ◽  
Diffusion Control ◽  
Lateral Side ◽  
Electron Microscopic ◽  
Initial Shape ◽  
Hexagonal Shape ◽  
Initial Stage ◽  
Scanning Electron Microscopic ◽  
Spherical Diffusion

The processes of Pb electrodeposition in the diffusion control were examined by the scanning electron microscopic (SEM) analysis of the formed crystals. Orientation of grains of hexagonal shape formed in the initial stage of electrodeposition strongly affected the final morphology of Pb crystals. Formation of Pb crystals of the different shape from the same initial shape was discussed by the effect of orientation of initially formed grains on the type of diffusion control. The spherical diffusion layer was formed around the tip of the hexagonal shaped grain oriented by the tip towards the bulk of solution leading to formation of elongated crystals in the growth process. On the other hand, the cylindrical type of diffusion was responsible for growth of hexagonal shaped grains oriented by the lateral side towards the bulk of solution. Pb crystals with well defined sides parallel to the surface area of macroelectrode were formed by this type of diffusion.

Comparison of microtubules and microfilaments in Tipula iridescent virus-infected and uninfected cells

1985 ◽  
Vol 63 (6) ◽  
pp. 543-552 ◽  
Author(s):  
Robert W. Seagull ◽  
Peter E. Lee ◽  
Monica Frosch
Keyword(s):  
Virus Assembly ◽  
Electron Microscopic ◽  
Iridescent Virus ◽  
Initial Stage ◽  
Large Virus ◽  
Infected Cells ◽  
Specific Association ◽  
Globular Cells ◽  
Cytoskeletal Elements ◽  
Microscopic Techniques

Microfilaments and microtubules were detected in Estigmene acrea virus-infected cells using fluorescent immunochemistry and in sections by electron microscopy. Twelve hours following infection of cells with Tipula iridescent virus, large virus assembly sites developed in the cytoplasm. The majority of infected cells exhibit no detectable changes in the cytoskeleton during the initial stage of infection, when virus assembly sites are forming. Actin was localized either in cytoplasmic spikes or in patches at the cell surface. Microtubules were parallel to the long axis of elongate cells or randomly distributed in globular cells. Intermediate filaments were not detected using either immunofluorscent or electron microscopic techniques. In later stages of infection some cells exhibit a specific association between actin and the virus assembly site. The significance of this observation remains unclear since only a portion of the population exhibits this change. From this study, it does not appear that cytoskeletal elements are of importance in the formation or maintenance of the membrane-free cytoplasmic virus assembly sites.

scholarly journals ON THE DIFFERENTIAL RESPONSE OF SARCOPLASM AND MYOPLASM TO DENERVATION IN FROG MUSCLE

1965 ◽  
Vol 27 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Umberto Muscatello ◽  
Alfredo Margreth ◽  
Massimo Aloisi
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Early Response ◽  
Frog Muscle ◽  
Active Synthesis ◽  
Electron Microscopic ◽  
Dynamic Changes ◽  
Initial Stage ◽  
Membrane Bound ◽  
Denervated Muscles ◽  
Tissue Fractionation

Electron microscopic evidence is presented that the early response to denervation ("simple atrophy") of the semitendinosus m. of the frog is characterized by a greater prominence of the sarcoplasmic reticulum and by the presence, in the interfibrillar spaces, of mitochondria which are more numerous and smaller than in normal muscle. In contrast with the dynamic changes of the sarcoplasmic structural components, the myofibrils showed a progressive decrease in diameter after denervation and throughout the period studied. By carrying out tissue fractionation experiments, the yield of microsome-protein was found significantly greater in the denervated muscles, as compared with the contralateral controls, in this initial stage. Under the conditions attending the overdevelopment of the sarcoplasmic reticulum (SR), denervated semitendinosus m. incorporated valine-C14 into proteins more actively than the control pairs. The denervated muscles also showed an increase in the number of freely scattered and membrane-bound ribosomes and of polyribosomes, suggesting a more active synthesis of the SR membranes. Pronounced atrophy of the myofibrils, disorganization of the SR, and an increased number of ribonucleoprotein particles lying in the enlarged interfibrillar spaces were the main ultrastructural features of "degenerative atrophy" in frog muscle in the late periods after denervation. The probably adaptive character of the early changes occurring on denervation of frog muscle is discussed.

Transmission electron microscopic studies on an initial stage in the conversion process from α-tricalcium phosphate to hydroxyapatite

2003 ◽  
Vol 18 (11) ◽  
pp. 2633-2638 ◽  
Author(s):  
Masato Tamai ◽  
Toshiyuki Isshiki ◽  
Koji Nishio ◽  
Mitsuhiro Nakamura ◽  
Atsushi Nakahira ◽  
...  
Keyword(s):  
Tricalcium Phosphate ◽  
Amorphous Layer ◽  
Conversion Process ◽  
Electron Microscopic ◽  
Microstructural Changes ◽  
Hydrolysis Method ◽  
Transmission Electron ◽  
Initial Stage ◽  
Microscopic Studies ◽  
Dendritic Structures

The microstructural changes in the initial stage of a conversion process of α-tricalcium phosphate [α-Ca3(PO4)2] (α-TCP) to hydroxyapatite [Ca10(PO4)6(OH)2] (HAp) by the hydrolysis method were investigated by transmission electron microscopy (TEM). To investigate the microstructural changes that take place during the conversion process, we prepared two types of α-TCP specimens for TEM: α-TCP powder and sintered α-TCP thin film. According to our results, the microstructural changes can be summarized as follows. At first, the surface of the α-TCP was covered with an amorphous calcium phosphate layer, resulting from hydration or the dissolution of α-TCP. Subsequently, the nucleation of HAp occurred on the amorphous layer, and then dendritic structures appeared on the layer. Thereafter, the dendritic structures would grow into needlelike fine HAp crystals.

Failure Analysis of an Automotive Component (Cardan Yoke) by Scanning Electron Microscopy

2012 ◽  
Vol 326-328 ◽  
pp. 187-192
Author(s):  
Antônio Augusto Couto ◽  
A.H.P. Andrade ◽  
Danieli A.P. Reis ◽  
Jan Vatavuk
Keyword(s):  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Term Operation ◽  
Initial Stage ◽  
Metallurgical Processing ◽  
Specific Loading ◽  
Bending Stresses ◽  
Micro Dimples ◽  
Scanning Electron

Two SAE 1541 (0.39%C; 1.44%Mn; 0.23%Si; 0.16%Ni; 0.16%Cr) carbon steel cardan yokes that were forged, machined, quenched and tempered, as part of the manufacturing process to ensure long term operation under specific loading conditions, failed during its manufacture. The cardan yokes ruptured in the bearing seat region while these were being straightened by bending. This study deals with fracture analysis that was carried out by visual inspection and scanning electron microscopic examination. The focus of this study was to investigate the fracture mechanism associated with the failures. Fractographs of the broken components indicated that the rupture initiated at the edges of the component, from preexisting cracks, due to the bending stresses during the straightening process. The initial stage of rupture was predominantly intergranular in the tempered martensite surface layer, revealing the brittle nature of the component. Cracks were observed at regions prone to stress concentration. Eventual rupture of the component probably initiated at these cracks. This behavior is probably related to metallurgical processing steps like quenching, that causes the formation of a banded structure and promotes circumferential and radial cracking before the tempering. The fracture surface revealed regions with micro dimples and a large smooth area with some elongated inclusions. The morphology of these inclusions was cellular and originated at the grain boundaries of the primary austenite. These inclusions are probably MnS with a dendrite structure, capable of causing brittle intergranular rupture.

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