Scanning electron microscopy: a direct method of identifying pollen grains on moths (Noctuidae: Lepidoptera)

1978 ◽  
Vol 56 (9) ◽  
pp. 2050-2054 ◽  
Author(s):  
W. J. Turnock ◽  
J. Chong ◽  
B. Luit
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Direct Method ◽  
Pollen Grains ◽  
Scanning Electron Micrographs ◽  
Simple Method ◽  
Critical Point Drying ◽  
A Direct Method ◽  
Scanning Electron

A simple method of using scanning electron microscopy to observe pollen grains in situ on feral moths (Noctuidae) is described. This method does not require freeze drying, critical point drying, or any chemical fixation procedures to prepare the specimens for scanning. Pollen grains were found mainly on the proboscises of the moths and can be identified directly from the scanning electron micrographs, thus expediting the study of moth–plant relations.

Delicate Botanical Specimens Preserved for Scanning Electron Microscopy by Critical Point Drying

1971 ◽  
Vol 29 ◽  
pp. 450-451
Author(s):  
Arthur L. Cohen ◽  
Gerald E. Garner
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Freeze Drying ◽  
Animal Cell ◽  
Pollen Grains ◽  
Scanning Electron Micrographs ◽  
Animal Cells ◽  
Critical Point Drying ◽  
Scanning Electron

The surface forms and structures of animal cells have been strikingly preserved for scanning electron microscopy by freeze-drying and by critical point drying both by the method with CO2 used as the transitional fluid and the later procedure which uses a fluorocarbon (Freon 13) as a medium for the transition from the liquid to the gaseous environment. Freeze-drying is often prolonged (5-12 hours as compared with an hour or less by the critical point method) and in our experience with mold cultures on agar, the substrate shrivels and cracks and hyphal filaments are distorted.Despite, and possibly because of a flexible but inelastic cell wall, plant cells often show greater distortion than do animal cells after evaporative drying or replacement dehydration for mixrotechnical work. The animal cell membrane can contract more or less uniformly on drying - as shown by the numerous micrographs of well-preserved erythrocytes, while plant cell walls often crumple. The many scanning electron micrographs of partially collapsed pollen grains bear witness to this fact.

scholarly journals High resolution scanning electron microscopy of isolated and in situ cytoskeletal elements.

1979 ◽  
Vol 83 (1) ◽  
pp. 249-254 ◽  
Author(s):  
W Ip ◽  
D A Fischman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Intermediate Filaments ◽  
Actin Filaments ◽  
Critical Point Drying ◽  
Osmium Impregnation ◽  
Cytoskeletal Elements ◽  
Scanning Electron

Evidence is presented that cytoskeletal structures (actin filaments, intermediate filaments, and microtubules) can be resolved by scanning electron microscopy after osmium impregnation of biological material, using thiocarbohydrazide as a ligand, followed by critical-point drying. These different classes of filaments or tubules can be identified both as purified protein polymers and as structured organelles within cryofractured or detergent-extracted cells.

Alternative Method of Rapid Drying Vascular Specimens for Scanning Electron Microscopy

2003 ◽  
Vol 10 (2) ◽  
pp. 285-287 ◽  
Author(s):  
DáŠa Slížová ◽  
Otakar Krs ◽  
Blanka PospíŠilová
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Micrographs ◽  
Low Cost ◽  
High Rate ◽  
Drying Methods ◽  
Scanning Electron Micrographs ◽  
Air Drying ◽  
Critical Point Drying ◽  
Scanning Electron

Purpose: To report the use of hexamethyldisilazane (HMDS) as an alternative to critical point drying for preparing stented canine peripheral vessels for scanning electron microscopy (SEM). Technique: Vascular specimens were fixed in 4% formaldehyde overnight, dehydrated in a graded ethanol series, followed by immersion in 100% hexamethyldisilazane. After air drying, the specimens were mounted on stainless steel stubs, coated with gold, and examined in the SEM. The electron micrographs were of high quality, showing the layers of the vascular wall and the incorporated stent covered by a neointimal layer. The micrographs were comparable to corresponding histological sections, but detailed endothelial patterns were more visible. Conclusions: HMDS treatment and subsequent air drying provides good quality scanning electron micrographs that reveal both endothelial patterns and the layered architecture of stented vessels. The disadvantage of HMDS drying may be a shrinkage and distortion similar to other drying agents. Ease of handling, low cost, and a high rate of success are advantages that favor HMDS desiccation over other drying methods.

Preservation of Plant Cell Surfaces For Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 472-473
Author(s):  
Linda M. Sicko ◽  
Thomas E. Jensen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Filter Paper ◽  
Freeze Drying ◽  
Cell Surfaces ◽  
Air Drying ◽  
Popular Method ◽  
Critical Point Drying ◽  
Scanning Electron

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.

Development of the Foramen Secundum in the Chick as Observed by Scanning Electron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 212-213
Author(s):  
M.J.C. Hendrix ◽  
D.E. Morse
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Procaine Hydrochloride ◽  
Cardiac Anomaly ◽  
Chick Embryos ◽  
Congenital Cardiac Anomaly ◽  
Septal Defects ◽  
Critical Point Drying ◽  
Scanning Electron

Atrial septal defects are considered the most common congenital cardiac anomaly occurring in humans. In studying the normal sequential development of the atrial septum, chick embryos of the White Leghorn strain were prepared for scanning electron microscopy and the results were then extrapolated to the human heart. One-hundred-eighty chick embryos from 2 to 21 days of age were removed from their shells and immersed in cold cacodylate-buffered aldehyde fixative . Twenty-four embryos through the first week post-hatching were perfused in vivo using cold cacodylate-buffered aldehyde fixative with procaine hydrochloride. The hearts were immediately dissected free and remained in the fixative a minimum of 2 hours. In most cases, the lateral atrial walls were removed during this period. The tissues were then dehydrated using a series of ascending grades of ethanol; final dehydration of the tissues was achieved via the critical point drying method followed by sputter-coating with goldpalladium.

Intracellular structures of rapid frozen biological samples observed by high-resolution low-temperature Scanning Electron Microscopy

1989 ◽  
Vol 47 ◽  
pp. 736-737
Author(s):  
T. Inoué ◽  
H. Koike
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Liquid Nitrogen ◽  
Specimen Preparation ◽  
Chemical Fixation ◽  
Brown Adipose ◽  
Critical Point Drying ◽  
Temperature Scanning ◽  
Scanning Electron

Low temperature scanning electron microscopy (LTSEM) is useful to avoid artifacts such as deformation and extraction, because specimens are not subjected to chemical fixation, dehydration and critical-point drying. Since Echlin et al developed a LTSEM, many techniques and instruments have been reported for observing frozen materials. However, intracellular structures such as mitochondria and endoplasmic reticulum have been unobservable by the method because of the low resolving power and inadequate specimen preparation methods. Recently, we developed a low temperature SEM that attained high resolutions. In this study, we introduce highly magnified images obtained by the newly developed LTSEM, especially intracellular structures which have been rapidly frozen without chemical fixation.[Specimen preparations] Mouse pancreas and brown adipose tissues (BAT) were used as materials. After the tissues were removed and cut into small pieces, the specimen was placed on a cryo-tip and rapidly frozen in liquid propane using a rapid freezing apparatus (Eiko Engineering Co. Ltd., Japan). After the tips were mounted on the specimen stage of a precooled cryo-holder, the surface of the specimen was manually fractured by a razor blade in liquid nitrogen. The cryo-holder was then inserted into the specimen chamber of the SEM (ISI DS-130), and specimens were observed at the accelerating voltages of 5-8 kV. At first the surface was slightly covered with frost, but intracellular structures were gradually revealed as the frost began to sublimate. Gold was then coated on the specimen surface while tilting the holder at 45-90°. The holder was connected to a liquid nitrogen reservoir by means of a copper braid to maintain low temperature.

Criteria for the evaluation of low-temperature Scanning Electron Microscopy

1986 ◽  
Vol 44 ◽  
pp. 902-903
Author(s):  
Alan Beckett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Conformational Changes ◽  
Chemical Vapour ◽  
List Type ◽  
Dimensional Changes ◽  
Critical Point Drying ◽  
Temperature Scanning ◽  
Scanning Electron

Low temperature scanning electron microscopy (LTSEM) has been evaluated with special reference to its application to the study of morphology and development in microorganisms. A number of criteria have been considered and have proved valuable in assessing the standard of results achieved. To further aid our understanding of these results, it has been necessary to compare those obtained by LTSEM with those from more conventional preparatory procedures such as 1) chemical fixation, dehydration and critical point-drying; 2) freeze-drying with or without chemical vapour fixation before hand.The criteria used for assessing LTSEM for the above purposes are as follows: 1)Specimen immobilization and stabilization2)General preservation of external morphology3)General preservation of internal morphology4)Exposure to solvents5)Overall dimensional changes6)Cell surface texture7)Differential conformational changes8)Etching frozen-hydrated material9)Beam damage10)Specimen resolution11)Specimen life

High-Resolution Resistance Mapping in SEM

2018 ◽  
Author(s):  
Grigore Moldovan ◽  
Wolfgang Joachimi ◽  
Guillaume Boetsch ◽  
Jörg Jatzkowski ◽  
Frank Altman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Reference Structure ◽  
Total Resistance ◽  
Embedded Electronics ◽  
Improved Performance ◽  
Mapping Techniques ◽  
Scanning Electron

Abstract This work presents advanced resistance mapping techniques based on Scanning Electron Microscopy (SEM) with nanoprobing systems and the related embedded electronics. Focus is placed on recent advances to reduce noise and increase speed, such as integration of dedicated in situ electronics into the nanoprobing platform, as well as an important transition from current-sensitive to voltagesensitive amplification. We show that it is now possible to record resistance maps with a resistance sensitivity in the 10W range, even when the total resistance of the mapped structures is in the range of 100W. A reference structure is used to illustrate the improved performance, and a lowresistance failure case is presented as an example of analysis made possible by these developments.

scholarly journals Design and Characterization of Microscale Auxetic and Anisotropic Structures Fabricated by Multiphoton Lithography

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 446
Author(s):  
Ioannis Spanos ◽  
Zacharias Vangelatos ◽  
Costas Grigoropoulos ◽  
Maria Farsari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Performance ◽  
Element Analysis ◽  
Mechanical Responses ◽  
Multiphoton Lithography ◽  
Anisotropic Structures ◽  
Scanning Electron

The need for control of the elastic properties of architected materials has been accentuated due to the advances in modelling and characterization. Among the plethora of unconventional mechanical responses, controlled anisotropy and auxeticity have been promulgated as a new avenue in bioengineering applications. This paper aims to delineate the mechanical performance of characteristic auxetic and anisotropic designs fabricated by multiphoton lithography. Through finite element analysis the distinct responses of representative topologies are conveyed. In addition, nanoindentation experiments observed in-situ through scanning electron microscopy enable the validation of the modeling and the observation of the anisotropic or auxetic phenomena. Our results herald how these categories of architected materials can be investigated at the microscale.

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