Fertilization Membranes and Sea Urchin Embryos Studied by Scanning Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 530-531
Author(s):  
Walter J. Humphreys ◽  
David T. Lindsay
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Sea Urchin ◽  
Structural Features ◽  
Vitelline Membrane ◽  
Cortical Granules ◽  
Freeze Dried ◽  
Fertilization Membrane ◽  
Ultrathin Sections ◽  
Scanning Electron

Scanning electron microscopy (SEM) of specimens freeze-dried after fixation in Parducz fixative and ultrathin sections of the sea urchin, Strongylocentrotus purpuratus show that the egg is covered by many papillae about 0.25μ in diameter and 0.5μ long (Fig. 1a). When the vitelline layer lifts away from the surface of the egg at the time of fertilization it has many uniformly spaced protrusions that persist as prominent and consistent structural features of the fertilization membrane, which forms when material from ruptured cortical granules is added to the inner surface of the raised vitelline membrane. Dimensions of the protrusions, their spacing on the membrane, and their projection in a direction outward from the egg (Fig. 1b) suggests that they originate when the vitelline layer lifts away from the egg surface in the form of a somewhat distorted and expanded replica of the papillae-bearing surface of the unfertilized egg.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

Scanning Electron Microscopy-cuticular Lesions on the Roundworm Ascaris Suum

1970 ◽  
Vol 28 ◽  
pp. 114-115
Author(s):  
P. A. Madden ◽  
W. R. Anderson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Freeze Drying ◽  
Room Temperature ◽  
Secondary Electron ◽  
Distilled Water ◽  
Freeze Dried ◽  
Silver Paint ◽  
To Come ◽  
Scanning Electron

The intestinal roundworm of swine is pinkish in color and about the diameter of a lead pencil. Adult worms, taken from parasitized swine, frequently were observed with macroscopic lesions on their cuticule. Those possessing such lesions were rinsed in distilled water, and cylindrical segments of the affected areas were removed. Some of the segments were fixed in buffered formalin before freeze-drying; others were freeze-dried immediately. Initially, specimens were quenched in liquid freon followed by immersion in liquid nitrogen. They were then placed in ampuoles in a freezer at −45C and sublimated by vacuum until dry. After the specimens appeared dry, the freezer was allowed to come to room temperature slowly while the vacuum was maintained. The dried specimens were attached to metal pegs with conductive silver paint and placed in a vacuum evaporator on a rotating tilting stage. They were then coated by evaporating an alloy of 20% palladium and 80% gold to a thickness of approximately 300 A°. The specimens were examined by secondary electron emmission in a scanning electron microscope.

The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

1994 ◽  
Vol 52 ◽  
pp. 178-179
Author(s):  
Nancy R. Wallace ◽  
Craig C. Freudenrich ◽  
Karl Wilbur ◽  
Peter Ingram ◽  
Ann LeFurgey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Course ◽  
Vertical Plane ◽  
Mantle Cavity ◽  
Qualitative Assessment ◽  
Calcium Deposition ◽  
Free Swimming ◽  
Freeze Dried ◽  
Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

scholarly journals Scanning electron microscopy of freeze-dried protein foams.

1982 ◽  
Vol 46 (11) ◽  
pp. 2881-2883 ◽  
Author(s):  
Naofumi KITABATAKE ◽  
Hirotaka SASAKI ◽  
Etsushiro DOI
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Freeze Dried ◽  
Scanning Electron

Wood identification of charcoal with 3D-reflected light microscopy

IAWA Journal ◽  
2020 ◽  
Vol 41 (4) ◽  
pp. 478-489 ◽  
Author(s):  
Valentina Zemke ◽  
Volker Haag ◽  
Gerald Koch
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Field Emission ◽  
Polarized Light ◽  
Structural Features ◽  
Light Illumination ◽  
Reflected Light ◽  
Carbonized Wood ◽  
Scanning Electron

Abstract The present study focusses on the application of 3D-reflected light microscopy (3D-RLM) for the wood anatomical identification of charcoal specimens produced from domestic and tropical timbers. This special microscopic technique offers a detailed investigation of anatomical features in charcoal directly compared with the quality of field emission scanning electron microscopy (FESEM). The advantages of using the 3D-RLM technology are that fresh fracture planes of charcoal can be directly observed under the microscope without further preparation or surface treatment. Furthermore, the 3D-technique with integrated polarized light illumination creates high-contrast images of uneven and black charcoal surfaces. Important diagnostic structural features such as septate fibres and intercellular canals can be clearly detected and intervessel pits are directly measured. The comparison of the microscopic analyses reveals that 3D-reflected light microscopy (3D-RLM) provides an effective alternative technique to conventional field emission scanning electron microscopy for the identification of carbonized wood.

Cobalt Based Alloys for Dental Applications

2013 ◽  
Vol 583 ◽  
pp. 175-178 ◽  
Author(s):  
Brandusa Ghiban ◽  
Cristina Maria Borţun ◽  
Alexandru Ghiban ◽  
Nicolae Ghiban
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Behaviour ◽  
Structural Features ◽  
Molybdenum Content ◽  
Cobalt Alloys ◽  
Mo Content ◽  
Dental Applications ◽  
Scanning Electron

The present paper put in evidence the mechanical behaviour of some commercial dental cobalt alloys, after own classification. The experimental cobalt alloys were classified in according either with molybdenum content, or with Cr+Mo content. A hierarcy of the alloys was finally made. The fractographic surfaces were investigate both by stereomacroscopy and scanning electron microscopy, putting in evidence the main structural features.

Scanning Electron Microscopy of Freeze-dried Protein Foams

1982 ◽  
Vol 46 (11) ◽  
pp. 2881-2883
Author(s):  
Naofumi Kitabatake ◽  
Hirotaka Sasaki ◽  
Etsushiro Doi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Freeze Dried ◽  
Scanning Electron

Extra-alveolar veins are contiguous with, and leak fluid into, periarterial cuffs in rabbit lungs

1991 ◽  
Vol 71 (4) ◽  
pp. 1606-1613 ◽  
Author(s):  
D. L. Luchtel ◽  
L. Embree ◽  
R. Guest ◽  
R. K. Albert
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Interstitial Fluid ◽  
Blue Dye ◽  
Alveolar Pressure ◽  
Vessel Lumen ◽  
Freeze Dried ◽  
Orange G ◽  
Pulmonary Arterial ◽  
Scanning Electron

We previously observed physiological evidence that arterial and venous extra-alveolar vessels shared a common interstitial space. The purpose of the present investigation was to determine the site of this continuity to improve our understanding of interstitial fluid movement in the lung. Orange G and Evans blue dyes were added to the arterial and venous reservoirs, respectively, of excised rabbit lungs as they were placed 20 cmH2O into zone 1 (pulmonary arterial and venous pressures = 5 cmH2O, alveolar pressure = 25 cmH2O). After 10 s or 4 h the lungs were fixed by immersion in liquid N2, freeze-dried, cut into 5-mm serial slices, and examined by light macroscopy. Serial sections of 0.25–0.5 mm were subsequently examined by scanning electron microscopy. In the animals subjected to the zone 1 stress for 4 h, arterial and venous extra-alveolar vessels were surrounded by cuffs of edema. The edema ratio (cuff area divided by vessel lumen area) was greater around arteries than veins and decreased with increasing vessel size. Periarterial cuffs usually contained orange dye and frequently contained both orange and blue dye. Lymphatics containing orange or blue dye were frequently seen in periarterial cuffs. Scanning electron microscopy demonstrated that extra-alveolar veins of approximately 100 microns diameter were anatomically contiguous with arterial extra-alveolar vessel cuffs. In rabbit lungs, both arterial and venous extra-alveolar vessels (and/or alveolar corner vessels) leak fluid into perivascular cuffs surrounding arterial extra-alveolar vessels, and lymphatics located in the periarterial cuff contain fluid that originates from both the arterial and venous extra-alveolar vessels.

Field Emission Scanning Electron Microscopy Studies of Industrial Polymers - A Survey

1998 ◽  
Vol 4 (S2) ◽  
pp. 814-815
Author(s):  
E.F. Osten ◽  
M.S. Smith
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Field Emission ◽  
Low Voltage ◽  
Structural Features ◽  
X Ray Diffraction ◽  
Styrene Acrylonitrile ◽  
Microscopy Techniques ◽  
Scanning Electron

We are using the term "Industrial Polymers" to refer to polymers [plastics] that are produced by the ton or (in the case of films) by the mile. For example, in descending order of world-wide use (tonnage), the top eight of these polymers are polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), styrene polymers (including polystyrene - PS, and acrylonitrile-butadienestyrene/ styrene-acrylonitrile - ABS/SAN), polyesters (PETP), polyurethane (PU), phenolics and aminoplastics.Industrial polymers, which have been produced by the millions of tons for the last five decades and are of obvious social and economic importance, have been exhaustively characterized. Structural features which affect physical properties and indicate process variables have been studied by many techniques other than microscopy (x-ray diffraction, thermal analysis, rheology, chromatographies, etc.). Microscopy techniques for polymer characterization have been well documented. Our motivation to apply field emission (high resolution) scanning electron microscopy to the study of polymers is: (1) The application of low voltage, high resolution SEM to biological materials is well characterized.

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