Microtubule organization in the siphonous green alga bryopsis: An ultrastructural observation with Electron Spectroscopic Imaging (ESI)

1993 ◽  
Vol 51 ◽  
pp. 136-137
Author(s):  
Sheng Jun Wei ◽  
Kyle Bishop
Keyword(s):  
Electron Microscopy ◽  
Green Alga ◽  
Ultrastructural Observation ◽  
Electron Spectroscopic Imaging ◽  
Fixation Procedure ◽  
Microtubule Organization ◽  
Low Contrast ◽  
Cell Structures ◽  
Transmission Electron ◽  
Feature Resolution

Transmission electron microscopy (TEM) has been routinely used to study the ultrastructure of microtubules (MT). However, we found that some MTs in the filamentous green alga we examined could not be easily recognized using conventional brightfield imaging, because of low contrast. Electronspectroscopic imaging (ESI) microscopy using the imaging electron energy filter solves many problems involving low contrast and feature resolution. By ESI, the contrast can be tuned and optimized so that images with higher resolution can be produced. In the present study we used ESI to improve the image quality in order to clearly resolve the MTs.A specimen of the giant marine green alga Bryopsis sp. was prepared following a new modified double fixation procedure of our own to preserve cell structures (Fig. 1). In brief, the branched alga was cut into small segments of about 1 cm in length in 2% glutaraldehyde in 0.1 M phosphate at pH 7.2.

scholarly journals A Novel Microchip Technique for Quickly Identifying Nanogranules in an Aqueous Solution by Transmission Electron Microscopy: Imaging of Platelet Granules

2020 ◽  
Vol 10 (14) ◽  
pp. 4946
Author(s):  
Nguyen Thi Thu Trang ◽  
Jungshan Chang ◽  
Wei-An Chen ◽  
Chih-Chun Chen ◽  
Hui-Min Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Human Platelet ◽  
Blood Collection ◽  
Ultrastructural Observation ◽  
Microscopy Imaging ◽  
Transmission Electron ◽  
Aqueous Conditions

Ultrastructural observation of biological specimens or nanogranules usually requires the use of electron microscopy. Electron microscopy takes a lot of time, requires many steps, and uses many chemicals, which may affect the native state of biological specimens. A novel microchip (K-kit) was used as a specimen kit for in situ imaging of human platelet granules in an aqueous solution using a transmission electron microscope. This microchip enabled us to observe the native human platelet granules very quickly and easily. The protocols included blood collection, platelet purification, platelet granule isolation, sample loading into this microchip, and then observation by a transmission electron microscope. In addition, these granules could still remain in aqueous solution, and only a very small amount of the sample was required for observation and analysis. We used this microchip to identify the native platelet granules by negative staining. Furthermore, we used this microchip to perform immunoelectron microscopy and successfully label α-granules of platelets with the anti-P-selectin antibody. These results demonstrate that the novel microchip can provide researchers with faster and better choices when using a transmission electron microscope to examine nanogranules of biological specimens in aqueous conditions.

Fabrication and Characterization of Nanostructured Surface Layer of 38CrSi Steel

2007 ◽  
Author(s):  
Shi-Ning Ma ◽  
De-Ma Ba ◽  
Chang-Qing Li ◽  
Fan-Jun Meng
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Surface Layer ◽  
Grain Refinement ◽  
Fine Particles ◽  
Nanostructured Surface ◽  
Cell Structures ◽  
Strain And Strain Rate ◽  
Transmission Electron ◽  
Average Grain Size

A nanocrystalline surface layer was fabricated on a 38CrSi Steel with tempered sorbite structure by using Supersonic Fine Particles Bombarding (SFPB). The microstructural evolution of SFPB-treated specimens under different processing conditions was characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Experimental evidence showed severe plastic deformation and obvious grains refinement were observed and a nanocrystalline surface layer (grain size < 100nm) was found after SFPB treatment. The thickness of nanostructured surface layer varies from a few to about 25μm as treated time increasing from 80s to 240s, but the grain size varies slightly. For the sample treated for 240s, the average grain size of equiaxed nanocrystallites with random crystallographic orientations on the top surface layer is about 16nm. The indexing of diffraction rings indicates nanostructured surface layer consists of ferrite and cementite phases without any evidence of a new phase. The structure size increases gradually from nano-scale to original-scale with an increase of the distance from the top surface layer. In the region about 20–30μm deep from the top surface, the microstructures are mainly composed of 60–100nm roughly equiaxed grains and subgrains. Some subbounsaries are composed of dense dislocation walls (DDWs). In this regime some cell structures are also seen, which are separated by dislocation lines (DTs) and some DDWs. Experimental analysis indicate coarse-grains are gradually refined into nano-sized grains by dislocations activity with gradual increase of strain and strain rate from matrix to treated surface. Both ferrite and cementite phases occur grain refinement. Grain refinement of 38CrSi sample is mainly attributed to the movement of dislocation.

Electron spectroscopic imaging and diffraction: applications II materials science

1992 ◽  
Vol 50 (2) ◽  
pp. 1198-1199
Author(s):  
J. Mayer
Keyword(s):  
Electron Microscopy ◽  
Energy Loss ◽  
Materials Science ◽  
Spectroscopic Imaging ◽  
Electron Spectroscopic Imaging ◽  
Imaging Spectrometer ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Electron Spectroscopic Diffraction ◽  
Electron Energy Loss

With imaging energy filters becoming commercially available in transmission electron microscopy many of the limitations of conventional TEM instruments can be overcome. Energy filtered images of diffraction patterns can now be recorded without scanning using efficient parallel (2-dimensional detection. We have evaluated a prototype of the Zeiss EM 912 Omega, the first commercially available electron microscope with integrated imaging Omega energy filter. Combining the capabilities of the imaging spectrometer with the principal operation modes of a TEM gives access to many new qualitative and quantitative techniques in electron microscopy. The basis for all of them is that the filter selecte electrons within a certain energy loss range ΔE1 <ΔE < ΔE2 and images their contribution to an image (electron spectroscopic imaging, ESI) or a diffraction pattern (electron spectroscopic diffraction, ESD) In many applications the filter is only used to remove the inelastically scattered electrons (elastic or zero loss filtering). Furthermore, the electron energy loss spectrum can be magnified and recorded with serial or parallel detection.

Microstructure of a bearing-grade silicon nitride

1999 ◽  
Vol 14 (12) ◽  
pp. 4621-4629 ◽  
Author(s):  
Mingqi Liu ◽  
Sia Nemat-Nasser
Keyword(s):  
Electron Microscopy ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
Amorphous Film ◽  
Boundary Phase ◽  
X Ray Diffraction ◽  
Intimate Contact ◽  
Low Contrast ◽  
Transmission Electron ◽  
Grade Silicon

The microstructure of a bearing-grade silicon nitride, prepared by pressureless sintering with Y2O3, AlN, and TiO2 additives and then hot-isostatically pressed, is examined with high-resolution transmission electron microscopy, scanning electron microscopy, and x-ray diffraction. The material consists of large acicular β–Si3N4 grains and small equiaxial α–Si3N4 grains. An amorphous phase containing the sintering aids is observed at the two-grain boundaries and at the grain pockets. No crystalline boundary phase is identified. The α-to-β and β-to-β grain boundaries appear straight and well defined. The dominant crystalline planes observed at the β-grain boundaries are (1010) and (1120). The intergranular spacing of the two-grain boundaries (α-to-β and β-to-β) is 1.0 nm when a high-contrast boundary phase is present, and it is 0.8 nm when a low-contrast boundary phase is present, confirming that the film thickness is strongly dependent on the boundary-phase composition. The α-to-α boundaries are often curved, and the thickness of the amorphous film at these boundaries varies from 0.7 to 1.1 nm. Evidence of near-intimate contact between β-grains is also observed.

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