The restoration of blurred electron micrographs

1986 ◽  
Vol 44 ◽  
pp. 180-181
Author(s):  
Bridget Carragher ◽  
David A. Bluemke ◽  
Michael J. Potel ◽  
Robert Josephs
Keyword(s):  
Cross Section ◽  
Electron Micrographs ◽  
Relative Motion ◽  
Finite Thickness ◽  
Image Plane ◽  
Helical Axis ◽  
Thin Sections ◽  
Structural Details

We have investigated the feasibility of restoring blurred electron micrographs. Two related problems have been considered; the restoration of images blurred as a result of relative motion between the specimen and the image plane, and the restoration of images which are rotationally blurred about an axis. Micrographs taken while the specimen is drifting result in images which are blurred in the direction of motion. An example of rotational blurring arises in micrographs of thin sections of helical particles viewed in cross section. The twist of the particle within the finite thickness of the section causes the image to appear rotationally blurred about the helical axis. As a result, structural details, particularly at large distances from the helical axis, will be obscured.

Studies on Thrombolysis with Streptokinase

1971 ◽  
Vol 25 (02) ◽  
pp. 354-378 ◽  
Author(s):  
R Gottlob ◽  
L Stockinger ◽  
U Pötting ◽  
G Schattenmann
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Whole Blood ◽  
Jugular Vein ◽  
Thin Sections ◽  
The Third ◽  
Morphological Findings ◽  
Blood Clots ◽  
Arteries And Veins

SummaryIn vitro whole blood clots of various ages, experimental thrombi produced in the jugular vein of rabbits and human thrombi from arteries and veins were examined in semi-thin sections and by means of electron microscopy.In all types of clots examined a typical course of retraction was found. Retraction starts with a dense excentrical focus which grows into a densification ring. After 24 hours the entire clot becomes almost homogeneously dense; later a secondary swelling sets in.Shortly after coagulation the erythrocytes on the rim of the clot are bi-concave discs. They then assume the shape of crenate spheres, turn into smooth spheres and finally become indented ghosts which have lost the largest part of their contents. In the inner zone, which makes up the bulk of the clot, we observed bi-concave discs prior to retraction. After retraction we see no crenations but irregularly shaped erythrocytes. Once the secondary swelling sets in, the cross-section becomes polygonal and later spherical. After extensive hemolysis we observe the “retiform thrombus” made up of ghosts.Experimental and clinical thrombi present the same morphology but are differentiated from in vitro clots by: earlier hemolysis, immigration of leukocytes, formation of a rim layer consisting of fibrin and thrombocytes, and the symptoms of organization. Such symptoms of organization which definitely will prevent lysis with streptokinase were found relatively late in experimental and clinical thrombi. Capillary buds and capillary loops were never found in clinical thrombi prior to the third month.The morphological findings agree with earlier physical and enzymatic investigations. The observation that phenomena of reorganization occur relatively late and frequently only in the rim areas of large thrombi explains why lytic therapy is possible in some of the chronic obliterations.

Automated 3D measurement of fiber cross section morphology in handsheets

2012 ◽  
Vol 27 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Christian Lorbach ◽  
Ulrich Hirn ◽  
Johannes Kritzinger ◽  
Wolfgang Bauer
Keyword(s):  
Image Analysis ◽  
Cross Section ◽  
Cross Sections ◽  
Image Plane ◽  
3D Measurement ◽  
Cross Sectional ◽  
Fiber Cross Section ◽  
Fiber Wall ◽  
Sectional Shape ◽  
Cross Section Geometry

Abstract We present a method for 3D measurement of fiber cross sectional morphology from handsheets. An automated procedure is used to acquire 3D datasets of fiber cross sectional images using an automated microtome and light microscopy. The fiber cross section geometry is extracted using digital image analysis. Simple sample preparation and highly automated image acquisition and image analysis are providing an efficient tool to analyze large samples. It is demonstrated that if fibers are tilted towards the image plane the images of fiber cross sections are always larger than the true fiber cross section geometry. In our analysis the tilting angles of the fibers to the image plane are measured. The resulting fiber cross sectional images are distorted to compensate the error due to fiber tilt, restoring the true fiber cross sectional shape. We use an approximated correction, the paper provides error estimates of the approximation. Measurement results for fiber wall thickness, fiber coarseness and fiber collapse are presented for one hardwood and one softwood pulp.

A Massive System of Microtubules Associated with Cytoplasmic Movement in Telotrophic Ovarioles

1970 ◽  
Vol 6 (2) ◽  
pp. 431-449
Author(s):  
H. C. MACGREGOR ◽  
H. STEBBINGS
Keyword(s):  
Electron Micrographs ◽  
Thin Sections ◽  
Positive Form ◽  
Form Birefringence ◽  
Terminal Filament ◽  
Telotrophic Ovary ◽  
Oocyte Cytoplasm ◽  
Heavy Labelling

The telotrophic ovary of Notonecta glauca glauca consists of 7 ovarioles. Each ovariole comprises, from front to rear, a terminal filament, a trophic region, a prefollicular region, and a series of 10-15 follicles of progressively increasing size The trophic region is largely syncytial and is made up of polyploid trophic nuclei packed around a central trophic core The cytoplasm of the trophic core is continuous with the cytoplasm of each oocyte through a system of trophic tubes. There is one trophic tube per oocyte. The trophic nuclei have large nucleoli. There are a few small nucleoli in the oocyte nuclei The cytoplasm of the trophic core, the trophic tubes, and the oocytes is rich in RNA. Autoradiographs of sections of ovarioles fixed 2 h after injection of [3H]uridine into animals show label over the trophic nuclei only. Eight-hour autoradiographs show heavy labelling of the trophic region and label over the front ends of the trophic tubes, but little label over the posterior regions of the tubes or the oocyte cytoplasm. Later autoradiographs mdicate that label gradually spreads backwards from the trophic core, along the trophic tubes, and progressively builds up in the oocyte cytoplasm These observations are thought to indicate synthesis of RNA in the trophic region and movement of RNA from the trophic core along the trophic tubes to the oocytes The trophic core and tubes show brilliant positive form birefringence with respect to their lengths. This birefringence can be reduced by keeping animals at 2 °C for 12 h, and eliminated by placing ovarioles in 1 % colchicine for 6 h. Electron micrographs of thin sections of ovarioles show that trophic core and tubes are densely and uniformly packed with ribosomes and microtubules The latter are lined up along the trophic tubes. There are about 30000 microtubules evident in a TS through a trophic tube 15µm wide. Lengths of microtubules up to 2µm have been observed. Ribosomes are packed between the microtubules but are excluded from regions where the spacing between adjacent microtubules is less than 25 nm The contribution of the trophic region to the oocytes and the role of the microtubules in maintaining or facilitating the movement of ribosomes along the trophic tubes is discussed

Structural cross-bridges between microtubules and mitochondria in central axons of an insect (Periplaneta americana)

1977 ◽  
Vol 27 (1) ◽  
pp. 255-272
Author(s):  
D.S. Smith ◽  
U. Jarlfors ◽  
M.L. Cayer
Keyword(s):  
Electron Micrographs ◽  
Mitochondrial Membrane ◽  
Periplaneta Americana ◽  
Freeze Fracture ◽  
Outer Mitochondrial Membrane ◽  
Thin Sections ◽  
Cross Bridge ◽  
Multiple Association ◽  
Random Models ◽  
Cross Bridges

The distribution of microtubules and mitochondria in central axons of an insect (Periplaneta americana) is assessed by comparison between counts on micrographs and computed axon random ‘models’. These studies show that the observed multiple association of microtubules with individual mitochondria is statistically highly significant. Electron micrographs of thin sections show that linkage is effected by physical cross-bridge, possibly comprising components from the microtubule and mitochondrion. Linear particle arrays are described on the outer mitochondrial membrane in freeze-fracture replicas, and tentatively related to the bridges seen in thin sections. The results are discussed in terms of proposed roles of microtubules in neurons and other cells.

LARVAL SKETCHES OF SOME MICROLEPIDOPTERA, CHIEFLY NORTH AMERICAN

1972 ◽  
Vol 104 (S88) ◽  
pp. 7-83 ◽  
Author(s):  
Margaret Rae MacKay
Keyword(s):  
Electron Micrographs ◽  
North American ◽  
Scanning Electron Micrographs ◽  
Structural Details ◽  
Scanning Electron

AbstractPresented here, with notes, are 55 plates of illustrations: 48 are larval sketches representing 48 species in 18 families of Microlepidoptera; the remaining seven are scanning electron micrographs of larvae of three of the families, Lyonetiidae, Bucculatrigidae, and Stigmellidae. The illustrations suggest interesting affinities in some instances, are useful as identification aids, and show structural details not hitherto observed or recognized as important taxonomically.

Ein Pockenvirus-Modell aus Äquipotentialflächen

1962 ◽  
Vol 17 (5) ◽  
pp. 310-313 ◽  
Author(s):  
Dimitrij Lang ◽  
Albrecht K. Kleinschmidt
Keyword(s):  
Physical Model ◽  
Virus Particle ◽  
Electron Micrographs ◽  
Morphological Features ◽  
High Similarity ◽  
Thin Sections ◽  
Constant Potential

A physical model of the mature pox virus particle is given by calculated surfaces of constant potential as found in some electrostatic or other fields and is compared with electron micrographs of thin sections of mature canary pox virus. It is built up by selected surfaces of constant potential V=1/r1+1/r2+1/r3 +1/r4 = constant where r1, r2, r3 and r4 stand for the distances between a point in a surface and four potential generating centers arranged in the corners of a square or a rectangle. The possible biophysical reasons for the high similarity with the morphological features are discussed.

Cytoplasmic surface and intramembrane components of rat heart gap junctional proteins

1984 ◽  
Vol 246 (6) ◽  
pp. H865-H875 ◽  
Author(s):  
C. K. Manjunath ◽  
G. E. Goings ◽  
E. Page
Keyword(s):  
Electron Microscopy ◽  
Gap Junctions ◽  
Electron Micrographs ◽  
Rat Heart ◽  
Major Protein ◽  
Thin Sections ◽  
Cytoplasmic Surface ◽  
Sds Page ◽  
Junction Protein ◽  
Major Protein Band

Gap junctions were purified from rat hearts in the presence of absence of proteolysis inhibitors and examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and electron microscopy of thin sections. In absence of proteolysis inhibitors or in presence of ethylenediaminetetraacetic acid or leupeptin, gap junctions contained a single major protein band at relative molecular weight (Mr) 29,500 and minor bands at Mr 44,000–47,000, 17,750, and 16,500 and showed smooth cytoplasmic surfaces in electron micrographs. SDS-PAGE of junctions prepared with phenylmethylsulfonylfluoride (PMSF) showed markedly decreased intensity of the Mr 29,500 band and increased intensity of bands at Mr 44,000, 45,500, and 47,000; electron microscopy of these gap junctions showed presence of a fuzzy layer on their cytoplasmic surfaces. Urea (8 M) could not remove this fuzzy layer. In electron micrographs of rat ventricular myocytes, cytoplasmic surfaces of gap junctions were fuzzy. We conclude that rat heart gap junction protein consists of an intramembrane component (Mr 29,500) that extends into the “gap” and a cytoplasmic surface component (Mr 14,500–17,500) that corresponds to the fuzzy layer and is hydrolyzable by a serine protease.

LYSOZYME SENSITIVITY OF THE CELL WALL OF PSEUDO-MONAS AERUGINOSA: FURTHER EVIDENCE FOR THE ROLE OF THE NON-PEPTIDOGLYCAN COMPONENTS IN CELL WALL RIGIDITY

1966 ◽  
Vol 12 (1) ◽  
pp. 105-108 ◽  
Author(s):  
K. Jane Carson ◽  
R. G. Eagon
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Electron Micrographs ◽  
Cell Walls ◽  
Gram Negative Bacteria ◽  
Normal Cells ◽  
Thin Sections ◽  
Gram Negative ◽  
Cell Wall Rigidity

Electron micrographs of thin sections of normal cells of Pseudomonas aeruginosa showed the cell walls to be convoluted and to be composed of two distinct layers. Electron micrographs of thin sections of lysozyme-treated cells of P. aeruginosa showed (a) that the cell walls lost much of their convoluted nature; (b) that the layers of the cell walls became diffuse and less distinct; and (c) that the cell walls became separated from the protoplasts over extensive cellular areas. These results suggest that the peptidoglycan component of the unaltered cell walls of P. aeruginosa is sensitive to lysozyme. Furthermore, it appears that the peptidoglycan component is not solely responsible for the rigidity of the cell walls of Gram-negative bacteria.

scholarly journals Slender body theory for particles with non-circular cross-sections with application to particle dynamics in shear flows

2019 ◽  
Vol 877 ◽  
pp. 1098-1133 ◽  
Author(s):  
Neeraj S. Borker ◽  
Donald L. Koch
Keyword(s):  
Cross Section ◽  
Relative Motion ◽  
Cross Sections ◽  
Stokes Flow ◽  
Unit Length ◽  
Fluid Velocity ◽  
Simple Shear Flow ◽  
Slender Body Theory ◽  
Aspect Ratios ◽  
Cross Sectional Dimension

This paper presents a theory to obtain the force per unit length acting on a slender filament with a non-circular cross-section moving in a fluid at low Reynolds number. Using a regular perturbation of the inner solution, we show that the force per unit length has $O(1/\ln (2A))+O(\unicode[STIX]{x1D6FC}/\ln ^{2}(2A))$ contributions driven by the relative motion of the particle and the local fluid velocity and an $O(\unicode[STIX]{x1D6FC}/(\ln (2A)A))$ contribution driven by the gradient in the imposed fluid velocity. Here, the aspect ratio ($A=l/a_{0}$) is defined as the ratio of the particle size ($l$) to the cross-sectional dimension ($a_{0}$) and $\unicode[STIX]{x1D6FC}$ is the amplitude of the non-circular perturbation. Using thought experiments, we show that two-lobed and three-lobed cross-sections affect the response to relative motion and velocity gradients, respectively. A two-dimensional Stokes flow calculation is used to extend the perturbation analysis to cross-sections that deviate significantly from a circle (i.e. $\unicode[STIX]{x1D6FC}\sim O(1)$). We demonstrate the ability of our method to accurately compute the resistance to translation and rotation of a slender triaxial ellipsoid. Furthermore, we illustrate novel dynamics of straight rods in a simple shear flow that translate and rotate quasi-periodically if they have two-lobed cross-section, and rotate chaotically and translate diffusively if they have a combination of two- and three-lobed cross-sections. Finally, we show the remarkable ability of our theory to accurately predict the motion of rings, retaining great accuracy for moderate aspect ratios (${\sim}10$) and cross-sections that deviate significantly from a circle, thereby making our theory a computationally inexpensive alternative to other Stokes flow solvers.

scholarly journals Optical diffraction of the Z lattice in canine cardiac muscle.

1977 ◽  
Vol 75 (3) ◽  
pp. 818-836 ◽  
Author(s):  
M A Goldstein ◽  
J P Schroeter ◽  
R L Sass
Keyword(s):  
Cardiac Muscle ◽  
Electron Micrographs ◽  
Cross Sections ◽  
Optical Diffraction ◽  
Square Lattice ◽  
Thin Sections ◽  
Diffraction Patterns ◽  
Nemaline Rods

Optical diffraction patterns from electron micrographs of both longitudinal and cross sections of normal and anomalous canine cardiac Z bands have been compared. The data indicate that anomalous cardiac Z bands resembling nemaline rods are structurally related to Z bands in showing a repeating lattice common to both. In thin sections transverse to the myofibril axis, both electron micrographs and optical diffraction patterns of the Z structure reveal a square lattice of 24 nm. This lattice is simple at the edge of each I band and centered in the interior of the Z band, where two distinct lattice forms have been observed. In longitudinal sections, oblique filaments visible in the electron micrographs correspond to a 38-nm axial periodicity in diffraction patterns of both Z band and Z rod. We conclude that the Z rods will be useful for further analysis and reconstruction of the Z lattice by optical diffraction techniques.

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