II. Some new developments in specimen preparation techniques. Introductory remarks

1971 ◽  
Vol 261 (837) ◽  
pp. 119-119 ◽  
Keyword(s):  
Electron Microscope ◽  
Subject Matter ◽  
Specimen Preparation ◽  
Chemical Processing ◽  
Preparation Technique ◽  
Native State ◽  
New Developments ◽  
The Subject ◽  
Restricted Use ◽  
Preparation Techniques

The purpose of any specimen preparation technique is to prepare a sample of material ‘fixed’ in some way as near as possible to its native state, so that its structure has not changed significantly by the time the specimen is examined in the electron microscope, stained if necessary so that it gives adequate contrast, and, in some cases, additionally stained or labelled so that some chemically distinct part of the structure can be identified. Now, these techniques cover an enormous field of work, and at a relatively short meeting like this, one has to select some particular aspects of it. The subject-matter of section II is especially concerned with techniques which involve physical rather than chemical processing of the specimen, and in particular ones which are still only in rather restricted use.

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

scholarly journals Specimen Preparation for Condoms

2007 ◽  
Vol 15 (5) ◽  
pp. 40-41 ◽  
Author(s):  
Gan Phay Fang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Polymer Material ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Sem Imaging ◽  
Preparation Techniques ◽  
Scanning Electron

Specimen preparation techniques for Scanning Electron Microscope (SEM) imaging of condoms as reported by Rosenzweig et al revealed a variety of artifacts. The artifacts were classified as ridging, cracking and melting. The purpose of this article is to introduce a simple specimen preparation technique for condoms to be evaluated via SEM without any surface artifacts. This technique involves the use of two chrome washers to sandwich the condom. The sandwiched condom specimen is then subjected to coating before mounting on an aluminium stub. The execution of this technique requires patience and practice so as not to damage the condom. The method may be applied to any similar polymer material.

Electron Microscopic Observation of Biological Specimens in Their Native State by Employing Cryogenic Techniques

1972 ◽  
Vol 30 ◽  
pp. 410-411 ◽  
Author(s):  
Tokio Nei ◽  
Haruo Yotsumoto ◽  
Yoichi Hasegawa ◽  
Yuji Nagasawa
Keyword(s):  
Electron Microscopic Observation ◽  
Surface Structures ◽  
Specimen Preparation ◽  
Native State ◽  
Electron Microscopic ◽  
Biological Specimen ◽  
Specimen Holder ◽  
Cold Stage ◽  
Preparation Techniques ◽  
Scanning Electron

In order to observe biological specimens in their native state, that is, still containing their water content, various methods of specimen preparation have been used, the principal two of which are the chamber method and the freeze method.Using its recently developed cold stage for installation in the pre-evacuation chamber of a scanning electron microscope, we have succeeded in directly observing a biological specimen in its frozen state without the need for such conventional specimen preparation techniques as drying and metallic vacuum evaporation. (Echlin, too, has reported on the observation of surface structures using the same freeze method.)In the experiment referred to herein, a small sliced specimen was place in the specimen holder. After it was rapidly frozen by freon cooled with liquid nitrogen, it was inserted into the cold stage of the specimen chamber.

Comparison of freeze-fractured yeast replicas using conventional TEM and low-voltage field-emission SEM

1989 ◽  
Vol 47 ◽  
pp. 74-75
Author(s):  
William P. Wergin ◽  
Eric F. Erbe ◽  
Terrence W. Reilly
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Voltage ◽  
Objective Lens ◽  
Specimen Preparation ◽  
Lens System ◽  
Air Drying ◽  
Preparation Techniques ◽  
Scanning Electron

Although the first commercial scanning electron microscope (SEM) was introduced in 1965, the limited resolution and the lack of preparation techniques initially confined biological observations to relatively low magnification images showing anatomical surface features of samples that withstood the artifacts associated with air drying. As the design of instrumentation improved and the techniques for specimen preparation developed, the SEM allowed biologists to gain additional insights not only on the external features of samples but on the internal structure of tissues as well. By 1985, the resolution of the conventional SEM had reached 3 - 5 nm; however most biological samples still required a conductive coating of 20 - 30 nm that prevented investigators from approaching the level of information that was available with various TEM techniques. Recently, a new SEM design combined a condenser-objective lens system with a field emission electron source.

Historically Speaking,—: Arithmetic problems 175 years ago

1961 ◽  
Vol 54 (5) ◽  
pp. 361-363
Author(s):  
Cecil B. Read
Keyword(s):  
Eighteenth Century ◽  
Subject Matter ◽  
Mathematics Teaching ◽  
New Developments ◽  
The Subject ◽  
Class Room

A commonly encountered criticism of present-day mathematics teaching is that we fail to take account of new developments; it is sometimes said that a mathematician of the seventeenth or eighteenth century could step into the modern class-room and be competent to teach any of the subject matter.

scholarly journals Rapid Cross-Section TEM Specimen Preparation of III-V Materials

2003 ◽  
Vol 11 (1) ◽  
pp. 29-32 ◽  
Author(s):  
R. Beanland
Keyword(s):  
Electron Microscope ◽  
Cross Section ◽  
Transmission Electron Microscope ◽  
Limited Resources ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Sample Type ◽  
Transmission Electron ◽  
Conventional Methods ◽  
The Cross

AbstractCross-section transmission electron microscope (TEM) specimen preparation of Ill-V materials using conventional methods can be a painful and time-consuming activity, with a day or more from receipt of a sample to examination in the TEM being the norm. This article describes the cross-section TEM specimen preparation technique used at Bookham Caswell. The usual time from start to finish is <1 hour. Up to 10 samples can be prepared at once, depending upon sample type. Most of the tools used are widely available and inexpensive, making the technique ideal for use in institutions with limited resources.

An Evaluation of FIB Cross-Sectioning Using a Cooling Stage for Metals and Alloys with Low Melting Point

2013 ◽  
Vol 753 ◽  
pp. 3-6 ◽  
Author(s):  
Hideki Matsushima ◽  
Toshiaki Suzuki ◽  
Takeshi Nokuo
Keyword(s):  
Electron Microscope ◽  
Melting Point ◽  
Low Temperature ◽  
Advanced Materials ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Electron Microscopic ◽  
Cooling Stage ◽  
Transmission Electron ◽  
Microscopic Evaluation

Functions of an observation and an analysis in electron microscope, such as scanning electron microscope (SEM) or transmission electron microscope (TEM) are indispensable to evaluate advanced materials. Therefore a specimen preparation technique, that is a front end of the electron microscopy, has become highly important, thus a choice of it affects a result of the evaluation. The authors was combined a cooling stage in FIB and applied it for evaluation of metals with low melting point. The electron microscopic evaluation of Lead solder, Indium, Tin and Bismuth, metals with low melting point, has been always discussed if the results represent the actual physics. Metals with low melting point are heat sensitive materials, so the comparison of cross-sectioning with room and low temperature, it can be said that low temperature cross-sectioning has less effect and keeps the actual physics of the sample. In this paper, some knowledge from comparisons of cross-sectioning with room and low temperature for metals with low melting point are reported.

scholarly journals La extracción de conocimiento y terminología a partir de corpus ad hoc: el uso de documentos digitales de la web pública

2021 ◽  
Vol 3 ◽  
Author(s):  
Pilar Sánchez-Gijón
Keyword(s):  
Subject Matter ◽  
Electronic Communication ◽  
Ad Hoc ◽  
Specialized Knowledge ◽  
New Developments ◽  
Technical Writers ◽  
Standard Terminology ◽  
The Subject ◽  
Conceptual Relations ◽  
State Of Affairs

Electronic communication accelerates the exchange of knowledge and information in areas of specialized knowledge. This state of affairs forces anyone involved in such communication (e.g. technical writers, technical translators) to remain up to date with new developments. Not only do professionals belonging to this group of people have to master the standard terminology of each specialized domain, they must also assimilate and understand the subject matter within which they are working. This article proposes a method for assembling and using specific corpora with a view to extracting from them systematic and bilingual knowledge relating to terminology, the conceptual relations between terms, and the knowledge that they represent. Special attention is devoted to the strategies that will enable professionals to use such corpora in English and in Spanish.

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