Polymorphism of microtriches in the cysticercoid of Ophryocotyle insignis Lonnberg, 1890 from the limpet Patella vulgata

1983 ◽  
Vol 61 (5) ◽  
pp. 1062-1070 ◽  
Author(s):  
Barbara M. MacKinnon ◽  
Michael D. B. Burt
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Anterior Margin ◽  
Transverse Section ◽  
External Surface ◽  
Larval Body ◽  
Patella Vulgata ◽  
Transmission Electron ◽  
Different Types

The mature cysticercoid of Ophryocotyle insignis, from Patella vulgata, was examined using transmission electron microscopy. Eight different types of microtriches were present over the tegument of the larval body and microvilli covered the caudal bladder, or cercomer. Rounded, modified microtriches were present on the external surface of the bladder enclosing the cysticercoid. Microtriches lining the retraction chamber ranged from small triangular projections having an electron-dense ridge along the anterior margin but having no shaft, to more typically shaped, larger microtriches having a cytoplasmic base, electron-dense shaft, and an electron-dense ridge along the anterior margin of the base. The scolex tegument had large robust microtriches which, in transverse section, had many projecting flanges. The microtriches on the rostellum were long and slender. Long, thin microtriches were present amongst the small spines on the suckers and short microtriches were found on the unspined areas of the suckers. Possible functions for the different types of microtriches are suggested and the significance of microvilli on the cercomer is discussed.

The influence of Pt and SrTiO3 interlayers on the microstructure of PbTiO3 thin films deposited by laser ablation on (001) MgO

1995 ◽  
Vol 10 (4) ◽  
pp. 791-794 ◽  
Author(s):  
S. Stemmer ◽  
S.K. Streiffer ◽  
W-Y. Hsu ◽  
F. Ernst ◽  
R. Raj ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Laser Ablation ◽  
Volume Fraction ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Transmission Electron ◽  
Electrical Conductivities ◽  
Different Types ◽  
Oriented Material

We have used conventional and high-resolution transmission electron microscopy to investigate the microstruture of epitaxial, ferroelectric PbTiO3 films grown by pulsed laser ablation on (001) MgO single crystals, and on MgO covered with epitaxial Pt or SrTiO3. Pronounced variations are found in the widths and lengths of a-axis-oriented domains in these films, although the volume fraction of a-axis-oriented material varies only weakly for the different types of samples. In addition, the films deposited onto Pt-coated MgO have a larger grain size than those deposited onto bare MgO or SrTiO3/MgO. Possible reasons for the variations in the distribution of a-axis-oriented material in these samples include differences in the elastic properties and electrical conductivities of the different substrate combinations.

Ultrastructure of the tegument and penetration glands of developing procercoids of Haplobothrium globuliforme Cooper, 1914 (Cestoda: Haplobothrioidea)

1985 ◽  
Vol 63 (6) ◽  
pp. 1470-1477 ◽  
Author(s):  
Barbara M. MacKinnon ◽  
Leokadia Jarecka ◽  
Michael D. B. Burt
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
De Novo ◽  
Secretory Granules ◽  
Anterior Part ◽  
The Body ◽  
Infective Stage ◽  
Larval Body ◽  
Penetration Gland ◽  
Transmission Electron

Developing procercoids of Haplobothrium globuliforme were examined using transmission electron microscopy. Procercoids require 12–20 days, at approximately 20 °C, to develop to the infective stage. Six-day-old procercoids have a microvillar tegument and numerous undifferentiated subtegumental cells. In 9-day-old procercoids the cercomer is visible as a distinct appendage at the posterior end. Developing microtriches are evident on the tegument of the larval body. These are long and slender, and bear small electron-dense tips. No degenerating microvilli were evident and the microtriches were never seen emerging de novo from the tegument. Fully developed procercoids, 15 days postinfection, have both robust and slender microtriches at the anterior end of the larva, and only long slender microtriches over the remainder of the body. The cercomer retains a microvillar tegument until the larva is fully developed, at which time the tegumental projections on the anterior-most part of the cercomer bear small electron-dense tips. Penetration glands in the anterior part of the larva contain electron-dense secretory granules. The penetration gland ducts, which extend to the tegument, are lined with microtubules.

High Resolution Transmission Electron Microscope Study of Amorphous and Partially Crystalline Fe7 8B1 3Si9 Alloy

1985 ◽  
Vol 58 ◽  
Author(s):  
A.R. Bhatti ◽  
J.C. Barry ◽  
B Cantor
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Microscope Study ◽  
Lattice Imaging ◽  
Transmission Electron ◽  
Different Types ◽  
Mean Size ◽  
Transmission Electron Microscope Study ◽  
Imaging Mode

ABSTRACTAmorphous and partially crystalline Fe7 8B1 3 Si9 alloys have been examined by high resolution transmission electron microscopy at 200kV. In lattice imaging mode, the as-quenched alloy shows small regions, with a mean size of - 20Å, consisting of well defined patterns of fringes. Three different types of crystals can be identified at the very earliest stages of crystallisation of the alloy.

scholarly journals Morphological characteristics and cell viability of coffee plants calli

2014 ◽  
Vol 44 (4) ◽  
pp. 660-665 ◽  
Author(s):  
Marlúcia Souza Pádua ◽  
Luciano Vilela Paiva ◽  
Luciano Coutinho da Silva ◽  
Kalynka Gabriella do Livramento ◽  
Eduardo Alves ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Viability ◽  
Coffea Arabica ◽  
Morphological Characteristics ◽  
Leaf Explants ◽  
Transmission Electron ◽  
Different Types ◽  
Coffee Plants ◽  
Cytoplasm Vacuolization

The aim of this research was to characterize and compare two types of calli from leaf explants of Coffea arabica (cultivar Catiguá). Cells of different types of callus were successfully characterized regarding viability and internal and external morphological characteristics. It was obtained two morphologically distinct types of callus: (i) yellow friable and (ii) transparent watery. The yellow friable calli showed higher cell viability and embryogenic characteristics. Scanning and transmission electron microscopy showed embryogenic characteristics in cells of the yellow friable calli evidenced by the presence of small and isodiametric cells, while transparent watery calli showed elongated cells and large cytoplasm vacuolization.

Preparation of Electropolished Transverse Sections of Thin Aluminum Sheet for Transmission Electron Microscopy

1987 ◽  
Vol 115 ◽  
Author(s):  
Steve Smith
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transverse Section ◽  
Aluminum Sheet ◽  
Specimen Preparation ◽  
Ion Milling ◽  
Transmission Electron ◽  
Thin Aluminum ◽  
Time Required

ABSTRACTThe preparation of transverse section TEM foils from thin (0.2 mm to 1.5 mm) aluminum sheet would usually be accomplished by a combination of dimpling and ion milling. Both of these techniques are time consuming. A technique has been developed which allows these transverse section foils to be prepared by electropolishing, which greatly reduces the time required for specimen preparation. This technique also produces far more thin area for examination than a comparable foil which has been dimpled and ion milled, and eliminates artifacts produced by ion milling.

Visualisation of Electrically Active Areas Using Electron Holography

2002 ◽  
Author(s):  
U. Muehle ◽  
A. Lenk ◽  
M. Lehmann ◽  
H. Lichte
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Electron Holography ◽  
Transmission Electron ◽  
Structural Details ◽  
Different Types ◽  
High Level ◽  
Technical Solutions

Abstract In accordance with the predictions of the International Semiconductor Association, a further decrease in the structural widths of semiconductor devices is expected. For an in-depth characterization of actual structural details, the transmission electron microscopy (TEM)-technique is becoming more and more significant. An urgent requirement is in the visualization of dimensions of the doped regions and estimation of p-n-junctions profile with a high level spatial resolution. The off-axis electron holography, a special TEM-technique, is able to visualize electrically active areas in semiconductors. This article describes a way to achieve sample preparation for TEM-holography from actual memory products and also provides an idea of the potential of this technique for semiconductor failure analysis. It shows that different types and sizes of FET's and testing structures could be visualized by focusing on the physical basics, technical solutions, and sample preparation.

scholarly journals Characterization of mouse spermatogonia by transmission electron microscopy

Reproduction ◽  
2002 ◽  
pp. 567-577 ◽  
Author(s):  
H Chiarini-Garcia ◽  
LD Russell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
B Cells ◽  
Nuclear Envelope ◽  
Type B ◽  
Intermediate Type ◽  
Functional Studies ◽  
Transmission Electron ◽  
Different Types

Characteristics of the various type A, intermediate (In) and B spermatogonia were determined in C57BL/6J mice using transmission electron microscopy. Spermatogonia were photographed at all stages of the cycle of the seminiferous epithelium. Over 450 images were taken. Spermatogonia could be classified into As, Apr, Aal, A1 cells, A2 cells, A3 cells, A4 cells, intermediate type and type B cells primarily on the basis of nuclear and nucleolar characteristics. The most primitive spermatogonia (As, Apr, Aal) had mottled chromatin; A1 cells contained homogeneously finely granular chromatin throughout the nucleus; A2, A3, A4 and intermediate type spermatogonia had progressively increasing amounts of chromatin encrusting the nuclear envelope; type B spermatogonia had less heterochromatin along the nuclear envelope, although the particles were more dense and rounded than in intermediate type spermatogonia. Mitochondrial size and position of Golgi complexes varied in different types of spermatogonia. These data show that types of spermatogonia can be differentiated such that these characteristics can be used in functional studies.

Structure of UMoO5 studied by single-crystal X-ray diffraction and high-resolution transmission electron microscopy

1996 ◽  
Vol 52 (6) ◽  
pp. 961-965 ◽  
Author(s):  
O. G. D'yachenko ◽  
V. V. Tabachenko ◽  
R. Tali ◽  
L. M. Kovba ◽  
B.-O. Marinder ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slight Excess ◽  
Transmission Electron ◽  
Different Types

A combination of X-ray diffraction and high-resolution transmission electron microscopy (HRTEM) has been used to study the crystal structure of molybdenum uranium pentoxide, UMoO5, obtained by hydrothermal and ceramic methods. Crystal data: Mr = 414.0, orthorhombic, Pbaa (number 54), a = 12.746 (1), b = 7.3494 (7), c = 4.1252 (2) Å, V = 386.4 (1) Å3, Z = 4, Dx = 7.116 Mg m−3, R = 0.037 for 723 reflections. The structure of UMoO5 is related to that of UVO5. Both are built up by slabs of pentagonal UO7 bipyramids with slabs of MO6 octahedra in-between. They differ in symmetry due to different types of displacement of the M atoms from the ab plane. The HRTEM study revealed a few defect regions in the UMoO5 crystals prepared by ceramic methods. Energy-dispersive spectroscopy (EDS) analyses indicate a slight excess of uranium in such crystals. Hypothetical models of defect regions are given.

Nature of interstratified kaolin-smectites in some Australian soils

Soil Research ◽  
1994 ◽  
Vol 32 (4) ◽  
pp. 805 ◽  
Author(s):  
GJ Churchman ◽  
PG Slade ◽  
PG Self ◽  
LJ Janik
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Infrared Spectroscopy ◽  
Clay Minerals ◽  
X Ray Diffraction ◽  
Size Fractions ◽  
X Ray ◽  
Transmission Electron ◽  
Different Types ◽  
Interstratified Phase

The clay minerals in the < 2 �m, and finer, size fractions of several horizons from each of five Australian soils of different types and from different locations have been analysed by X-ray diffraction, infrared spectroscopy, transmission electron microscopy and X-ray fluorescence. Samples from each profile contained a phase in which layers of smectite and of kaolin (positively identified as kaolinite) were randomly interstratified with each other. The relative proportions of the two types of layers varied widely. One interstratified phase contained 70% smectite. This value for smectite content of kaolin-smectites is as high as any reported in the literature. The charges associated with the interstratified smectite layers also differed substantially. Discrete kaolinite commonly occurred along with interstratified kaolinite-smectite, Towards the surfaces of the soils, the proportions of kaolinite in the interstratified phases increased at the expense of smectite.

Misfit Dislocations at Mismatched Epitactic Heterojunctions

1990 ◽  
Vol 198 ◽  
Author(s):  
Jane G. Zhu ◽  
C. Barry Carter ◽  
Chris J. Palmstrom
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Antiphase Boundary ◽  
Misfit Dislocations ◽  
Surface Steps ◽  
Transmission Electron ◽  
Different Types ◽  
Significant Factors

ABSTRACTThe formation and structures of misfit dislocations are significant factors in understanding heteroepitaxy of lattice-mismatched materials. In this study, GaAs/Si, CoGa/GaAs and ErAs/GaAs heterojunctions in materials grown by molecular-beam epitaxy have been characterized using transmission electron microscopy. Different types of misfit dislocations have been generated at these interfaces. The different dislocation configurations are discussed, along with interactions between 60° and 90° dislocations in GaAs/Si heterojunctions; the 60° dislocations might be associated with surface steps or edges of islands. The growth of antiphase boundary structures in the CoGa and ErAs grown on GaAs are proposed.

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