An ultrastructural study of the epicuticle of Ascaris suum

1991 ◽  
Vol 49 ◽  
pp. 306-307
Author(s):  
D. M. Ramnani ◽  
G. D. Cain
Keyword(s):  
Phosphate Buffer ◽  
Room Temperature ◽  
Body Wall ◽  
Intestinal Parasite ◽  
Ascaris Suum ◽  
Parasitic Nematodes ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Saline Medium

Ascaris suum, an intestinal parasite of swine, has a complex body wall, consisting of nine distinct layers when observed by transmission electron microscopy. The outermost layer of the cortex is a trilaminar region, the epicuticle, that is similar in appearance to plasma membrane. Parasitic nematodes interact with their hosts through this layer. The structure of the epicuticle is being studied with transmission and scanning electron microscopes.Parasites were obtained from an abattoir at Waterloo, Iowa, and maintained in Harpur's saline medium for up to two days. Cuticles were separated by microdissection and washed in 0.1M phosphate buffer, pH 7.2. Trump's universal fixative (4% Formaldehyde: 1% Glutaraldehyde in phosphate buffer, pH 7.2 ) was used for 1 h at room temperature for primary fixation. Surface charge of epicuticle was studied by incubating cuticle with cationized ferritin (Polysciences) at a concentration of lmg/ml in 0.1M phosphate buffer, pH 7.2, for 30 minutes at room temperature.

scholarly journals Investigation of Nanoelectrodes by Transmission Electron Microscopy

2001 ◽  
Vol 676 ◽  
Author(s):  
M. S. Kabir ◽  
S. H. Magnus Persson ◽  
Yimin Yao ◽  
Jean Phillippe Bourgoin ◽  
Serge Palacin
Keyword(s):  
Room Temperature ◽  
High Energy ◽  
Image Features ◽  
Electrical Characteristics ◽  
Conjugated Molecules ◽  
Atomic Force ◽  
Transmission Electron ◽  
High Energy Electrons ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

ABSTRACTElectrodes for making connections to single molecules and clusters must have separations smaller than 10 nm. They are therefore difficult or impossible to image with atomic force microscopes (AFM) or Scanning Electron Microscopes (SEM). We have fabricated nanoelelectrodes by different methods to contacts nanoclusters and conjugated molecules and investigated their properties in transmission electron microscope (TEM) and their electrical characteristics at room temperature and at 4.2K. The electrodes are made on SiN4 membranes, which is transparent to high energy electrons and which make it possible to image features of a few nanometers in TEM.

Graphene in Titan

2021 ◽  
Author(s):  
Rahul Kumar Kushwaha ◽  
Ambresh Mallya ◽  
Dipen Sahu ◽  
Jaya Krishna Meka ◽  
Sheng-Lung Chou ◽  
...  
Keyword(s):  
Room Temperature ◽  
Laboratory Experiments ◽  
Vacuum Ultraviolet ◽  
Physical Nature ◽  
Potassium Bromide ◽  
Aromatic Molecules ◽  
Transmission Electron ◽  
Polycyclic Aromatic ◽  
Plasma Spectrometer ◽  
Electron Microscopes

<p>Benzene (C<sub>6</sub>H<sub>6</sub>) ice has been observed in the Titan’s stratosphere [1], and benzonitrile (C<sub>6</sub>H<sub>5</sub>CN) is a possible constituent in the benzene and nitrogen-rich environment of Titan’s atmosphere [2]. The energetic processing of such aromatic molecules can synthesize large and complex aromatic molecules such as the Polycyclic Aromatic Hydrocarbons (PAHs). To-date a number of laboratory experiments have reported the formation of complex organics from the energetic processing of aromatic molecules [3-6]. In particular, Scanning Electron Microscopy (SEM) micrographs of the residues resulting from irradiated benzene ices are found to contain geometrically shaped particles [6]. Therefore, by employing electron microscopes, we can understand the physical nature of the dust leftover from the aromatic molecule irradiation.</p> <p>In the present investigation, we subjected benzonitrile ice made at 4 K to vacuum ultraviolet (9 eV) radiation at two beamlines, BL03 and BL21A2 of Taiwan Light Source at NSRRC, Taiwan. After irradiation, the ice was warmed to room temperature, which left a brownish residue on the Potassium Bromide (KBr) substrate. The VUV spectrum of the residue is observed to have characteristic aromatic signatures. The residue is then transferred to a quantifoil grid for High-Resolution Transmission Electron Microscope (HR- TEM) imaging. HR-TEM micrographs revealed the presence of graphene in the residue. This result suggests that N-graphene could be present in benzene and nitrogen-rich icy clouds of Titan. The high masses observed by the Cassini plasma spectrometer in Titan’s atmosphere could then be attributed to the presence of N-graphene along with the more common tholins [7].</p> <p><strong>References</strong></p> <p>[1] Vinatier S. et al. (2018) <em>Icarus, 310,</em> 89.</p> <p>[2] Loison J. C. et al. (2019) <em>Icarus 329,</em> 55.</p> <p>[3] Strazzulla G. et al. (1991) <em>A&A, 241</em>, 310.</p> <p>[4] Callahan M. P. et al. (2013) <em>Icarus, 226</em>, 1201.</p> <p>[5] James R. et al. (2019) <em>RSC Adv. 9</em> (10), 5453.</p> <p>[6] Rahul K. K. et al. (2020) <em>Spectrochim. Acta A, 231, </em>117797.</p> <p>[7] Rahul K. K. et al. (2020) <em>arXiv:2008.10011</em>.</p>

The Observation of NBC Precipitates In Steels In The Nanometer Range Using A Field Emission Gun Scanning Electron Microscope

1997 ◽  
Vol 3 (S2) ◽  
pp. 1243-1244 ◽  
Author(s):  
Raynald Gauvin ◽  
Steve Yue
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Incident Electron Energy ◽  
Beam Diameter ◽  
Probe Diameter ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

The observation of microstructural features smaller than 300 nm is generally performed using Transmission Electron Microscopy (TEM) because conventional Scanning Electron Microscopes (SEM) do not have the resolution to image such small phases. Since the early 1990’s, a new generation of microscopes is now available on the market. These are the Field Emission Gun Scanning Electron Microscope with a virtual secondary electron detector. The field emission gun gives a higher brightness than those obtained using conventional electron filaments allowing enough electrons to be collected to operate the microscope with incident electron energy, E0, below 5 keV with probe diameter smaller than 5 nm. At 1 keV, the electron range is 60 nm in aluminum and 10 nm in iron (computed using the CASINO program). Since the electron beam diameter is smaller than 5 nm at 1 keV, the resolution of these microscopes becomes closer to that of TEM.

The Morphology of Obliterative Arterial Diseases in Statu Nascendi

1979 ◽  
Author(s):  
M. Marshall ◽  
J. Staubesand ◽  
H. Hese
Keyword(s):  
Risk Factors ◽  
Electron Microscope ◽  
Blood Platelet ◽  
Arterial Disease ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Mini Pigs ◽  
Scanning Electron ◽  
Blood Platelet Aggregation

The arteries of mini pigs which had been exposed to the local or systemic action of recognised ‘risk factors’ for arterial disease were examined with the light microscope, and the transmission and scanning electron microscopes. Initially the scanning instrument revealed adhesions of platelets in different stages of development, but showed an apparently intact endothelium. With the transmission electron microscope, however, degenerative changes in the endothelium could be observed. Increased blood platelet aggregation was also present. After a few weeks we could see a remarkable focal thickening of the intima, together with deposits on the endothelium of platelets, erythrocytes and fibrin (“mixed microparietal thrombosis”). After 6 months fully developed arteriosclerosis of the abdominal aorta had appeared.

scholarly journals Precession Electron Diffraction Assisted Orientation Mapping in the Transmission Electron Microscope

2010 ◽  
Vol 644 ◽  
pp. 1-7 ◽  
Author(s):  
Joaquim Portillo ◽  
Edgar F. Rauch ◽  
Stavros Nicolopoulos ◽  
Mauro Gemmi ◽  
Daniel Bultreys
Keyword(s):  
Electron Diffraction ◽  
X Ray Diffraction ◽  
Promising Technique ◽  
Electron Backscattered Diffraction ◽  
Transmission Electron ◽  
Orientation Mapping ◽  
Precession Electron Diffraction ◽  
Electron Microscopes ◽  
Ebsd Technique ◽  
Scanning Electron Microscopes

Precession electron diffraction (PED) is a new promising technique for electron diffraction pattern collection under quasi-kinematical conditions (as in X-ray Diffraction), which enables “ab-initio” solving of crystalline structures of nanocrystals. The PED technique may be used in TEM instruments of voltages 100 to 400 kV and is an effective upgrade of the TEM instrument to a true electron diffractometer. The PED technique, when combined with fast electron diffraction acquisition and pattern matching software techniques, may also be used for the high magnification ultra-fast mapping of variable crystal orientations and phases, similarly to what is achieved with the Electron Backscattered Diffraction (EBSD) technique in Scanning Electron Microscopes (SEM) at lower magnifications and longer acquisition times.

Three Dimensional Mask Metrology by Off-Axis Electron Holography

2001 ◽  
Vol 7 (S2) ◽  
pp. 574-575
Author(s):  
Bernhard Frost ◽  
David C Joy
Keyword(s):  
Three Dimensional ◽  
Ccd Camera ◽  
Electron Holography ◽  
Dimensional Metrology ◽  
Transmission Electron ◽  
Stereo Photogrammetry ◽  
Real Objects ◽  
Electron Microscopes ◽  
Third Dimension ◽  
Scanning Electron Microscopes

Even though all real objects are three dimensional, imaging and metrology performed by using electron-beam tools such as scanning electron microscopes is inherently two dimensional. Any information about the third dimension must therefore be obtained by inference, or by time consuming special methods such as stereo-photogrammetry. If, however, the structures of interest are thin enough to be electron transparent then quantitative three dimensional metrology can be performed directly by using off-axis transmission electron holography. Here we demonstrate the application to a SCALPEL lithography mask which consists of chromium lines on a silicon support film. The off-axis holography was performed in a field emission transmission electron microscope, a Hitachi HF2000 operated at 200keV. The sample is positioned so that half the beam passes through the specimen while the rest travels only through the vacuum. An electrostatic biprism then recombines these two components to form the hologram which is recorded onto a CCD camera.

Whither Scanning Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 4-5
Author(s):  
T. E. Everhart
Keyword(s):  
Three Dimensional ◽  
Great Depth ◽  
Depth Of Field ◽  
Minimal Sample ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Dimensional Object ◽  
Scanning Electron Microscopes ◽  
Short Time ◽  
Scanning Electron

Although scanning electron microscopes have been available commercially for a relatively short time, their use is increasing rapidly. Countless persons have marvelled at their great depth of field, which produces an easily interpreted image of a three-dimensional object. Trained electron-microscopists have been impressed by the minimal sample preparation required for scanning microscope observation of inorganic objects, and of some organic objects. Non-specialists find the instrument easy to use, because many of the controls are related to familiar controls on television sets, on cathode-ray oscilloscopes, etc., and because the image on the cathode-ray tube screen is easy to interpret. Now seems the opportune moment to re-emphasize how the scanning electron microscope (SEM) differs fundamentally from the transmission electron (TEM), in order to insure that constraints imposed by the physics of image formation in the TEM will not be taken subconsciously as constraints in the SEM too.

Preparation of Helminths For Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 438-439
Author(s):  
Robert W. Weise
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Room Temperature ◽  
Parasitic Nematodes ◽  
Live Animal ◽  
Transmission Electron ◽  
Critical Point Drying ◽  
Scanning Electron

The role that scanning electron microscopy (SEM) is playing in descriptive helminthology is becoming more apparent in the literature. However, the majority of papers on the SEM of helminths have used conventional or modified light microscope techniques of fixation and dehydration, and not established SEM techniques in which freeze- and critical point-drying are routinely used. The present investigation was undertaken to examine the applicability of modified scanning and transmission electron microscope techniques for the preparation of certain helminths for SEM.Method I.– Live animal-parasitic nematodes were fixed in 6% phosphate buffered glutaraldehyde for 24 hr at room temperature.

Advances in the EM of Polymers

1981 ◽  
Vol 39 ◽  
pp. 334-337
Author(s):  
L. C. Sawyer
Keyword(s):  
Optical Microscopy ◽  
Small Group ◽  
Fiber Morphology ◽  
The Past ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Fine Structures ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

Recent advances in Analytical Electxon Microscopy (AEM) have changed the methods by which microicopists study polymer and fiber morphology. As polymeric materialis play a major role in our way of living - clothing, shelter, fuel, chemicals - the interest has spread from a small group of theoretical physicists to the larger group of applications scientists. Until forty years ago, optical microscopy (OM) provided the only microicopical means of observing the morphology of materials. Then transmission electron microscopes (TEM) brought a new depth and resolution of fine structures not previously known. The methodology of preparing materials for TEM, ultramicrotomy and replication, are revealing but tedious and replete with artifacts. Bridging the gap between OM and TEM the scanning electron microscopes (SEM), in use over the past fifteen years, have provided easily available and interpretable surface images of fibers, fabrics, membranes, films and composites. Finally, the limited resolution of the SEM has been improved by the use of modern composite instruments known as analytical electron microscopes (AEM).

Sign in / Sign up

Export Citation Format

Share Document