The X-ray diffraction and electron microscopic investigation of stable and metastable equilibria in Al-rich Al-Zn alloys

1974 ◽  
Vol 24 (5) ◽  
pp. 553-559 ◽  
Author(s):  
M. Simerská ◽  
P. Bartuška
Keyword(s):  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Zn Alloys

Nanocomposites Based on High-Tc Superconducting Ceramic 2212 BSCCO and their Properties

2014 ◽  
Vol 938 ◽  
pp. 210-214
Author(s):  
T.K. Jayasree ◽  
P. Predeep
Keyword(s):  
Sol Gel ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
X Ray Diffraction ◽  
Polymer Phase ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic ◽  
Scanning Electron Micrography ◽  
Superconducting Ceramic ◽  
Scanning Electron

High temperature superconducting (SC) 2212 BiSrCaCuO nanoparticles were prepared by Sol-Gel method. Precursor was characterized by X-ray diffraction (XRD) and scanning Electron micrography. The superconductor nanocomposites were fabricated by nanoparticles of the SC powder with NR/LLDPE blends. The superconductive properties of the sintered samples and the nanocomposites were studied. Transition to a superconducting state around 88K appeared in the parent sample and in the composites. The scanning electron microscopic investigation of the nanostructures of SC polymer ceramic nanocomposites shown nanoscale dispersion of BSCCO in the polymer phase uniformly.

scholarly journals An Electron Microscopic Investigation of the Cell Wall Organization of Conifer Tracheids and Conifer Cambium

1950 ◽  
Vol 3 (3) ◽  
pp. 265 ◽  
Author(s):  
AJ Hodge ◽  
AB Wardrop
Keyword(s):  
Cell Wall ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Electron Micrograph ◽  
Electron Microscopic ◽  
X Ray ◽  
Inner Surface ◽  
Cell Wall Organization ◽  
Optical Evidence

An electron micrograph of a replica of the inner surface of the secondarycell wall of a conifer tracheid, demonstrating the almost transverse orientationof the microfibrils in this layer, is presented. This evidence provides confirmationof the type of cell wall organization of conifer tracheids proposed inother investigations on the basis of X-ray and optical evidence and of microscopicexamination. The existence of fibrils of 50-100 A in diameter has beendemonstrated in cell wall fragments obtained by the disintegration of cambiuminitials and of conifer tracheids. It is suggested that these microfibrilsmay correspond to the "micelles" or "crystalline regions" inferred from X-rayexamination.

Transmission Electron Microscopic Investigation of Pt-Si Thin Films

1969 ◽  
Vol 27 ◽  
pp. 120-121
Author(s):  
Ronald M. Anderson ◽  
Somnath Dash
Keyword(s):  
Electron Diffraction ◽  
Ohmic Contacts ◽  
Semiconductor Device ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Reflection Electron Diffraction

Recently, studies of platinum-silicon ohmic contacts in semiconductor device metallurgy have prompted us to make an investigation into the nature of the reaction between silicon and platinum. We confined ourselves to Pt deposition temperatures, annealing temperatures, and thicknesses that were germane to the production of ohmic contacts.Transmission electron microscopy, selected area electron diffraction, and reflection electron diffraction analysis, coordinated with x-ray diffraction studies, were performed and allowed us to make the following observations.

Direct visualization of phase-separated domains in lipid membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 290-291
Author(s):  
S. W. Hui ◽  
T. P. Stewart
Keyword(s):  
Lipid Membranes ◽  
Structural Information ◽  
Freeze Fracture ◽  
Biological Molecules ◽  
Vacuum Drying ◽  
Direct Visualization ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Hydrocarbon Chains

Direct electron microscopic study of biological molecules has been hampered by such factors as radiation damage, lack of contrast and vacuum drying. In certain cases, however, the difficulties may be overcome by using redundent structural information from repeating units and by various specimen preservation methods. With bilayers of phospholipids in which both the solid and fluid phases co-exist, the ordering of the hydrocarbon chains may be utilized to form diffraction contrast images. Domains of different molecular packings may be recgnizable by placing properly chosen filters in the diffraction plane. These domains would correspond to those observed by freeze fracture, if certain distinctive undulating patterns are associated with certain molecular packing, as suggested by X-ray diffraction studies. By using an environmental stage, we were able to directly observe these domains in bilayers of mixed phospholipids at various temperatures at which their phases change from misible to inmissible states.

Light and electron microscopic investigation of adenohypophyses of germfree, food-restricted, and germfree-food restricted aging, male lobund-wistar rats

1988 ◽  
Vol 46 ◽  
pp. 352-353
Author(s):  
G. Ilse ◽  
K. Kovacs ◽  
N. Ryan ◽  
T. Sano ◽  
L. Stefaneanu ◽  
...  
Keyword(s):  
Wistar Rats ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Aging Male ◽  
Sprague Dawley ◽  
Electron Microscopic ◽  
Sprague Dawley Rats ◽  
Old Rats ◽  
Ad Libitum ◽  
Microscopic Findings

Germfree state and food restriction have been shown to increase life span and delay tumor occurrence in rats. We report here the histologic, immunocytochemical and electron microscopic findings of adenohypophyses of aging, male Lobund-Wistar rats raised at Lobund Laboratories. In our previous study, the morphologic changes in the adenohypophyses of old rats have been extensively investigated by histology, immunocytochemistry and electron microscopy. Lactotroph adenomas were frequent in Long-Evans and Sprague-Dawley rats, whereas gonadotroph adenomas were frequent in Sprague-Dawley and Wistar rats.Male Lobund-Wistar rats were divided into four groups: 1) conventional, which were raised under normal non-germfree environment and received food ad libitum; 2) germfree-food ad libitum; 3) conventional environment-food restricted and 4) germfree-food restricted. The adenohypophyses were removed from 6-month-, 18-month- and 30-month-old rats. For light microscopy, adenohypophyses were fixed in formalin and embedded in paraffin.

An Electron Microscopic Study of the Acute Effects of Hypothalamic Releasing Factors on the Anterior Pituitary Gland

1968 ◽  
Vol 26 ◽  
pp. 232-233
Author(s):  
P.W. Coates ◽  
E.A. Ashby ◽  
L. Krulich ◽  
A. Dhariwal ◽  
S. McCann
Keyword(s):  
Anterior Pituitary ◽  
Microscopic Investigation ◽  
Uranyl Acetate ◽  
Electron Microscopic Investigation ◽  
Electron Microscopic ◽  
Tissue Samples ◽  
Thin Sections ◽  
Dense Membrane ◽  
Membrane Bound ◽  
Releasing Factors

The morphologic effects on somatotrophs of crude sheep hypothalamic extract prepared from stalk-median eminence were studied by electron microscopy in conjunction with concurrently run bioassays performed on the same tissue samples taken from young adult male Sherman rats.Groups were divided into uninjected controls and injected experimentals sacrificed at 5', 15', and 30' after injection. Half of each anterior pituitary was prepared for electron microscopic investigation, the other half for bioassay. Fixation using collidine buffered osmium tetroxide was followed by dehydration and embedment in Maraglas. Uranyl acetate and lead citrate were used as stains. Thin sections were examined in a Philips EM 200.Somatotrophs from uninjected controls appeared as described in the literature (Fig. 1). In addition to other components, these cells contained moderate numbers of spherical, electron-dense, membrane-bound granules approximately 350 millicrons in diameter.

Fine Structural Classification of Chromophobe Adenomas of the Human Pituitary Gland

1975 ◽  
Vol 33 ◽  
pp. 378-379
Author(s):  
K. Kovacs ◽  
E. Horvath
Keyword(s):  
Pituitary Adenomas ◽  
Secretory Activity ◽  
Microscopic Investigation ◽  
Uranyl Acetate ◽  
Electron Microscopic Investigation ◽  
Electron Microscopic ◽  
Human Pituitary ◽  
Cytoplasmic Staining ◽  
Human Pituitary Gland ◽  
Microscopic Features

Chromophobe pituitary adenomas arise from adenohypophysial cells and fail to exhibit cytoplasmic staining with conventional acid or basic dyes by light microscopy. The aim of the present work was to study the electron microscopic features of these tumors, to separate them into distinct entities and to correlate their fine structural appearances with secretory activity.Among 48 surgically removed various pituitary adenomas 30 tumors were found which, based on the tinctorial characteristics of the cytoplasm, corresponded to chromophobe adenomas. For electron microscopic investigation pieces of these tumors were fixed in 2.5 per cent glutaraldehyde in Sorensen's buffer, post fixed in 1 per cent osmium tetroxide in Millonig's buffer, dehydrated in graded ethanol and embedded in Epon 812. Ultrathin sections were stained with uranyl acetate and lead citrate.By electron microscopy it was possible to separate chromophobe adenomas into 3 distinct entities: 1) adenomas consisting of sparsely granulated growth hormone cells (7 cases).

Temporal and spatial interrelationships of confronting cisternae to nuclear envelope

1992 ◽  
Vol 50 (1) ◽  
pp. 930-931
Author(s):  
John R. Palisano
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Tumor Cells ◽  
Hela Cells ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Serial Sections ◽  
Electron Microscopic ◽  
Fetal Rat ◽  
Temporal And Spatial

Although confronting cistemae (CC) have been observed in a variety of tumor cells and normal fetal rat, mouse, and human epithelial tissues, little is known about their origin or role in mitotic cells. While several investigators have suggested that CC arise from nuclear envelope (NE) folding back on itself during prophase, others have suggested that CC arise when fragments of NE pair with endoplasmic reticulum. An electron microscopic investigation of 0.25 um thick serial sections was undertaken to examine the origin of CC in HeLa cells.

Electron Microscopic investigation of crooke’s change in the pituitaries of patients with hypercorticism

1989 ◽  
Vol 47 ◽  
pp. 848-849
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
L. Stefaneanu ◽  
N. Losinski
Keyword(s):  
Nucleolar Organizer ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Ectopic Acth Syndrome ◽  
Nucleolar Organizer Regions ◽  
Electron Microscopic ◽  
Human Pituitary ◽  
Ectopic Acth ◽  
Crooke’S Hyalinization

Human pituitary corticotropins have unique morphologic markers: bundles of type-1 filaments, measuring approximately 70 A in width and representing cytokeratin. The extreme ring-like accumulation of type-1 filaments, known as Crooke's hyalinization, signals functional suppression of the corticotropins and occurs in endogenous and exogenous glucocorticoid excess, caused by ACTH-secreting pituitary adenoma, glucocorticoid secreting adrenocortical tumor, ectopic ACTH-syndrome and administration of pharmacologic doses of glucocorticoids. Cells of autonomous corticotroph adenomas usually do not show Crooke's hyalin change. A minority of these tumors, however, retains sensitivity to the negative feed-back effect of elevated blood glucocorticoid levels and display typical Crooke’s change.In the present study pituitary corticotropins in various phases of Crooke's hyalinization were investigated in patients with glucocorticoid excess of various origin, applying histology, immunocytochemistry, count of argyrophilic nucleolar organizer regions (AgNOR), and transmission electron microscopy.

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