X-ray microanalysis of frozen-hydrated bulk biological specimens: fundamental considerations

1978 ◽  
Vol 36 (2) ◽  
pp. 134-135
Author(s):  
W.C. Low ◽  
P.A. Burgio ◽  
L.F. Allard ◽  
S.L. BeMent ◽  
W.C. Bigelow ◽  
...  
Keyword(s):  
Biological Tissue ◽  
Ice Crystals ◽  
Tissue Fixation ◽  
Atmospheric Conditions ◽  
Bulk Specimen ◽  
X Ray ◽  
Ion Translocation ◽  
Cold Stage ◽  
Bulk Tissue ◽  
Scanning Electron

X-ray microanalysis and scanning electron microscopy used in conjunction with cold-stage techniques to examine frozen-hydrated bulk biological tissue is a promising method to determine the concentration and distribution of diffusible elements which are typically distorted by conventional techniques of biological tissue fixation. The proper application of this method, however, requires an understanding of the freezing and sublimation processes in bulk biological specimens, and the interaction of the electron beam with the bulk specimen in the frozen-hydrated state. These factors have been evaluated and are discussed below.One of the fundamental considerations in the examination of cryofixed bulk tissue is the formation of exogenous and endogenous ice crystals within the specimen or upon the surface of the specimen which can lead to tissue distortion and ion translocation. Techniques to minimize the exposure of the specimen to atmospheric conditions and to eleminate the formation of exogenous ice crystals have been developed by Burgio et al. (1978a), and Echlin and Moreton (1974).

scholarly journals Application of scanning electron microscopy to x-ray analysis of frozen-hydrated sections. I. Specimen handling techniques.

1981 ◽  
Vol 88 (2) ◽  
pp. 257-267 ◽  
Author(s):  
A J Saubermann ◽  
P Echlin ◽  
P D Peters ◽  
R Beeuwkes
Keyword(s):  
Specimen Handling ◽  
X Ray ◽  
Water Fraction ◽  
Tissue Sections ◽  
Cold Stage ◽  
Mass Fractions ◽  
Wet Weight ◽  
Cellular Compartments ◽  
Scanning Electron

X-ray microanalysis of frozen-hydrated tissue sections permits direct quantitative analysis of diffusible elements in defined cellular compartments. Because the sections are hydrated, elemental concentrations can be defined as wet-weight mass fractions. Use of these techniques should also permit determination of water fraction in cellular compartments. Reliable preparative techniques provide flat, smooth, 0.5 micrometers-thick sections with little elemental and morphological disruption. The specimen support and transfer system described permits hydrated sections to be transferred to the scanning electron microscope cold stage for examination and analysis without contamination or water loss and without introduction of extraneous x-ray radiation.

scholarly journals The Location of Impurities in Antarctic Ice

1988 ◽  
Vol 11 ◽  
pp. 194-197 ◽  
Author(s):  
E.W. Wolff ◽  
R. Mulvaney ◽  
K. Oates
Keyword(s):  
Freezing Point ◽  
Ice Sheet ◽  
Chemical Substance ◽  
Triple Junctions ◽  
Sea Salts ◽  
X Ray ◽  
Cold Stage ◽  
Micro Analysis ◽  
The Antarctic ◽  
Scanning Electron

Analysis of an ice sample with an estimated age of 125 years, from the Antarctic Peninsula, using a scanning electron microscope with a cold stage and an X-ray micro-analysis facility, shows that H2SO4 occurs mainly at triple junctions. Sea salts show no such localization. The different behaviour may be due to the freezing-point behaviour of each chemical substance, and to the effect this has both in the atmosphere and during recrystallization in the ice sheet. If this finding applies generally to other parts of the Antarctic ice sheet, it has major implications for many of the physical properties of Antarctic ice. In particular, it leads to a better understanding of the d.c. electrical conductivity of such ice.

scholarly journals Crystal orientation measurements using SEM–EBSD under unconventional conditions

2015 ◽  
Vol 30 (2) ◽  
pp. 104-108 ◽  
Author(s):  
Karsten Kunze
Keyword(s):  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Bulk Specimen ◽  
X Ray ◽  
Analytical Technique ◽  
Orientation Mapping ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Element Mapping ◽  
Scanning Electron

Electron backscatter diffraction (EBSD) is a micro-analytical technique typically attached to a scanning electron microscope (SEM). The vast majority of EBSD measurements is applied to planar and polished surfaces of polycrystalline bulk specimen. In this paper, we present examples of using EBSD and energy-dispersive X-ray spectroscopy (EDX) to analyze specimens that are not flat, not planar, or not bulk – but pillars, needles, and rods. The benefits of low vacuum SEM operation to reduced drift problems are displayed. It is further demonstrated that small and thin specimens enhance the attainable spatial resolution for orientation mapping (by EBSD or transmission Kikuchi diffraction) as well as for element mapping (by EDX).

Charge Implantation Measurement on Electron-Irradiated Insulating Materials by Means of a SEM Technique

2004 ◽  
Vol 10 (6) ◽  
pp. 697-710 ◽  
Author(s):  
Omar Jbara ◽  
Slim Fakhfakh ◽  
Mohamed Belhaj ◽  
Sebastien Rondot
Keyword(s):  
Electric Field ◽  
Alternative Possibility ◽  
External Effects ◽  
Bulk Specimen ◽  
Insulating Materials ◽  
Insulating Material ◽  
X Ray ◽  
Points Of View ◽  
Scanning Electron ◽  
Trapped Charge

The goal of this article is first to review the charging effects occurring when an insulating material is subjected to electron irradiation in a scanning electron microscope (SEM) and next their consequences from both scanning electron microscopy and electron probe microanalysis (EPMA) points of view. When bare insulators are observed, the so-called pseudo mirror effect leads to an anomalous contrast and also to an erroneous surface potential, VS, measurement when a Duane–Hunt limit (DHL) method is used. An alternative possibility is to use an electron toroidal spectrometer (ETS), specially adapted to a SEM, which directly gives the VS value. In the case of a bulk specimen coated with a grounded layer, although the layer prevents external effects of the trapped charge, the electric field beneath the coating is reinforced and leads to loss of ionizations that reduces the number of generated X-ray photons. To take into account both effects mentioned above, whether the studied insulator is coated or not, a method is proposed to deduce the trapped charge inside the insulator and the corresponding internal or external electric field.

scholarly journals The Location of Impurities in Antarctic Ice

1988 ◽  
Vol 11 ◽  
pp. 194-197 ◽  
Author(s):  
E.W. Wolff ◽  
R. Mulvaney ◽  
K. Oates
Keyword(s):  
Freezing Point ◽  
Ice Sheet ◽  
Chemical Substance ◽  
Triple Junctions ◽  
Sea Salts ◽  
X Ray ◽  
Cold Stage ◽  
Micro Analysis ◽  
The Antarctic ◽  
Scanning Electron

Analysis of an ice sample with an estimated age of 125 years, from the Antarctic Peninsula, using a scanning electron microscope with a cold stage and an X-ray micro-analysis facility, shows that H2SO4 occurs mainly at triple junctions. Sea salts show no such localization. The different behaviour may be due to the freezing-point behaviour of each chemical substance, and to the effect this has both in the atmosphere and during recrystallization in the ice sheet. If this finding applies generally to other parts of the Antarctic ice sheet, it has major implications for many of the physical properties of Antarctic ice. In particular, it leads to a better understanding of the d.c. electrical conductivity of such ice.

scholarly journals Studying a 2 millennia old bronze kettle using easily accessible characterization techniques

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Marta Kotlar ◽  
Nives Matijaković Mlinarić ◽  
Vladan Desnica ◽  
Katarina Marušić
Keyword(s):  
Electron Microscopy ◽  
Industrial Area ◽  
Ferrous Alloy ◽  
Atmospheric Conditions ◽  
Surface Layers ◽  
Sulphur Compounds ◽  
X Ray ◽  
Conservation Treatment ◽  
Tin Bronze ◽  
Scanning Electron

AbstractA bronze kettle dating from the 1st to 2nd century was found in a riverbed of the Kupa river in Croatia. After excavation it spent another 50 years in a depot of a museum in atmospheric conditions prior to starting the conservation treatment and our studies. A study on the surface layers development was performed to determine the whereabouts of the object through its history. This study is a demonstration of how such analysis can be used to reconstruct what the object went through during its life span. Samples taken from the kettle were observed by optical and scanning electron microscopy (SEM), and analysed by X-ray fluorescence (XRF), X-ray energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR).It was determined that the kettle is made of low-tin bronze, with low amounts of iron, aluminium, calcium and nickel. While being in the riverbed malachite formed on the kettle. After longer exposure to the river Si-oxides and CaCO3 formed on the surface of the kettle, over malachite. It was shown that the kettle probably had a ferrous alloy handle which degraded and disappeared in time. After excavation, the kettle came again in an oxygen-enriched atmosphere and formed new surface layers over the malachite layer. As the museum the kettle has been kept in since excavation is set in a highly industrial area sulphur compounds have been formed on the surface.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

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