scholarly journals Hemagglutination in gill capillaries of sheepshead, Archosargus probatocephalus (Perciformes: Sparidae), infected by a myxosporidean

2022 ◽  
Vol 31 (1) ◽  
Author(s):  
Carlos Azevedo ◽  
Graça Casal ◽  
Emerson Carlos Soares ◽  
Elsa Oliveira ◽  
Sónia Rocha ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Density ◽  
Intercellular Space ◽  
Experimental Studies ◽  
Parasite Development ◽  
Parasitic Infections ◽  
Physicochemical Processes ◽  
Transmission Electron ◽  
Close Proximity

Abstract During a survey Myxozoa, four specimens of the sheepshead (18 ± 1.5 cm and 59 ± 2.5 g) (Archosargus probatocephalus) were collected in the Ipioquinha river (Maceió/AL). Transmission electron microscopy observations revealed erythrocyte agglutinations in gill capillaries located near spherical cysts containing myxospores of the genus Henneguya. This hemagglutination partially or totally obstructed the gill capillaries. Erythrocytes occurred in close adherence to each other, with a closed intercellular space. A few lysed erythrocytes were observed among agglutinated cells. The reduced lumen of the capillaries was partially filled with amorphous dense homogenous material adhering to the erythrocytes. In addition, heterogeneous masses of irregular lower electron density were observed in the reduced channel of the capillary. The agglutinated erythrocytes appeared dense and homogenous, lacking cytoplasmic organelles. The nuclei had the appearance of normal condensed chromatin masses, generally without visible nucleoli. This occurrence of hemagglutination only in the capillaries located in close proximity to the developing myxozoan cysts suggests that parasite development may be a factor triggering erythrocyte agglutination. This is supported by previous experimental studies that showed a probable correlation between parasitic infections and hemagglutination. Nonetheless, further studies are necessary in order to better understand the physicochemical processes involved in this phenomenon.

Neoformation of halloysite on volcanic glass in a marine environment

Clay Minerals ◽  
1987 ◽  
Vol 22 (2) ◽  
pp. 179-185 ◽  
Author(s):  
T. Imbert ◽  
A. Desprairies
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Marine Environment ◽  
Experimental Studies ◽  
Volcanic Glass ◽  
Marine Environments ◽  
Thin Sections ◽  
Transmission Electron ◽  
Glass Shards

AbstractTransmission electron microscopy of ultramicrotomed thin-sections of Pleistocene and Eocene glass shards revealed the neoformation of (i) illite and (ii) halloysite at the glass periphery. According to previous experimental studies, halloysite neoformation in marine environments can occur on glass shards deposited in Si-rich sediments; an excess of Ca tends to inhibit the reaction.

scholarly journals Composite cuticle with heterogeneous layers in the leaf epidermis of Ficus elastica

2019 ◽  
Vol 49 (1) ◽  
Author(s):  
Ki Woo Kim
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Density ◽  
Leaf Epidermis ◽  
Leaf Cuticle ◽  
Transmission Electron

AbstractTwo distinct layers in terms of texture and electron density were observed in the leaf cuticle of Ficus elastica using transmission electron microscopy. As depicted in a model, an inner polysaccharide-rich layer and an outer cutin (or cutan)-rich layer may support the composite, heterogeneous concept of the leaf cuticle.

Marginal bands in camel erythrocytes

1979 ◽  
Vol 36 (1) ◽  
pp. 97-107
Author(s):  
W.D. Cohen ◽  
N.B. Terwilliger
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscopy ◽  
Electron Density ◽  
Electron Micrographs ◽  
Iron Content ◽  
Phase Contrast ◽  
Transmission Electron ◽  
Marginal Band ◽  
Whole Mounts

The elliptical, anucleate erythrocytes of camels have been examined for the presence of marginal bands and their constituent microtubules. Lysis of erythrocytes under microtubule-stabilizing conditions readily revealed marginal bands in at least 3 % of the cells, as observed by phase-contrast and darkfield light microscopy. Microtubules plus a marginal band-encompassing network of material are visible in lysed cell whole mounts with transmission electron microscopy. Marginal band microtubules are also evident in electron micrographs of thin-sectioned camel erythrocytes identifiable as reticuloyctes on the basis of submaximal electron density (reduced haemoglobin iron content) and presence of polysomes. The results suggest that marginal bands may be involved in morphogenesis of camel erythrocytes but are not required for maintenance of their ellipticity after cells are fully differentiated.

scholarly journals A Review of Grain Boundary and Heterointerface Characterization in Polycrystalline Oxides by (Scanning) Transmission Electron Microscopy

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 878
Author(s):  
Hasti Vahidi ◽  
Komal Syed ◽  
Huiming Guo ◽  
Xin Wang ◽  
Jenna Laurice Wardini ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Experimental Studies ◽  
Atomic Scale ◽  
Polycrystalline Materials ◽  
Structure Property ◽  
Ceramic Oxides ◽  
Structure Property Relationships ◽  
Transmission Electron ◽  
Scanning Transmission

Interfaces such as grain boundaries (GBs) and heterointerfaces (HIs) are known to play a crucial role in structure-property relationships of polycrystalline materials. While several methods have been used to characterize such interfaces, advanced transmission electron microscopy (TEM) and scanning TEM (STEM) techniques have proven to be uniquely powerful tools, enabling quantification of atomic structure, electronic structure, chemistry, order/disorder, and point defect distributions below the atomic scale. This review focuses on recent progress in characterization of polycrystalline oxide interfaces using S/TEM techniques including imaging, analytical spectroscopies such as energy dispersive X-ray spectroscopy (EDXS) and electron energy-loss spectroscopy (EELS) and scanning diffraction methods such as precession electron nano diffraction (PEND) and 4D-STEM. First, a brief introduction to interfaces, GBs, HIs, and relevant techniques is given. Then, experimental studies which directly correlate GB/HI S/TEM characterization with measured properties of polycrystalline oxides are presented to both strengthen our understanding of these interfaces, and to demonstrate the instrumental capabilities available in the S/TEM. Finally, existing challenges and future development opportunities are discussed. In summary, this article is prepared as a guide for scientists and engineers interested in learning about, and/or using advanced S/TEM techniques to characterize interfaces in polycrystalline materials, particularly ceramic oxides.

scholarly journals EFFECT OF ANTIBACTERIAL PREPARATIONS ON VIBRIO CHOLERAE EL TOR BIOFILMS

2017 ◽  
pp. 8-15 ◽  
Author(s):  
N. A. Selyanskaya ◽  
S. V. Titova ◽  
S. N. Golovin ◽  
L. A. Egiazaryan ◽  
L. M. Verkina ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microbial Communities ◽  
Vibrio Cholerae ◽  
Electron Density ◽  
Bacterial Cell ◽  
Transmission Electron ◽  
The Matrix ◽  
El Tor ◽  
Selection Of

Aim. Study the effect of antibacterial preparations on biofilms of Vibrio cholerae El Tor. Materials and methods. Sensitivity of V. cholerae El Tor (6 strains) to various concentrations of antibacterial preparations (doxycycline, tetracycline, levomycetin, rifampicin, gentamycin, ceftazidime) was determined (MD 4.2.2495-09). Transmission electron microscopy was used for visualization of the effect of preparations on biofilms. Results. The values of minimal inhibiting concentrations of antibacterial preparations against biofilms have increased by 5 - 100 times compared with plankton cultures. Certain smoothing of strands between the bacterial cell and substrate, alteration of vibrios’ form, reduction of electron density of the matrix with an increase of its transparency were observed during electron-microscopy of the effect of antibacterial preparations on the biofilm. Conclusion. Study of the effect of antibacterial preparations on biofilms could increase effectiveness of rational antibiotics therapy of infections by selection of preparations that disrupt functioning of microbial communities.

Dual Implantations of Ti and C into Sintered Α-Sic and Hot Pressed Si3n4

1989 ◽  
Vol 157 ◽  
Author(s):  
R.S. Bhattacharya ◽  
A.K. Rai ◽  
S.C. Kung ◽  
D. Patrizio
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Chemical Nature ◽  
No Oxidation ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Close Proximity ◽  
Before And After ◽  
D Values

ABSTRACTDual ion implantations of Ti+ and C+ into sintered a-SiC and hot pressed SÌ3N4 have been studied by Rutherford backscattering spectroscopy (RBS) combined with plan/cross section view transmission electron microscopy (TEM). The samples were analyzed before and after annealing at 1200°C for 2 hours in a vacuum of 1x10-6 torr. The results were compared with single ion implantation of Ti+. RBS analysis showed that no oxidation occurred during annealing and Ti diffused toward the surface in both SiC and SigN^ Cross section TEM analysis revealed the formation of TiC precipitates in SiC due to both dual (Ti+ + C+) and single (Ti+) ion implantations. Precipitates were found to form in SÌ3N4 as well; however, because of very close proximity of observed d values with those of TiC, TiN and β-SiC, it was not possible to uniquely identify the chemical nature of these precipitates. Thermo-dynamic calculations were performed to explain the observed results.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

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