scholarly journals Sulphure in epidermal keratohyalin granules: a quantitative assay by x-ray microanalysis

1976 ◽  
Vol 22 (1) ◽  
pp. 161-171
Author(s):  
H. Jessen ◽  
P.D. Peters ◽  
T.A. Hall
Keyword(s):  
Electron Microscope ◽  
Envelope Protein ◽  
Absolute Quantitation ◽  
Adult Rats ◽  
X Ray ◽  
Sulphur Concentration ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Different Types ◽  
Keratohyalin Granule

The elemental composition of different types of keratohyalin granules from the epidermis of newborn and adult rats was studied by means of an EMMA-4 analytical electron microscope, equipped with an energy-dispersive X-ray spectrometer. An absolute quantitation of the sulphur concentration in keratohyalin granules was performed. The results demonstrate that epidermal keratohyalin granules are chemically heterogeneous. A type of keratohyalin granule present in the nuclei and cytoplasm of epidermal cells from both newborn and adult rats - termed single granules - is rich in sulphur, having a content of 2-5-3-6%. Other types of keratohyalin granules, which differ in newborn and adult rats, contain a sulphur-poor component; they often have a sulphur-rich component as well. The sulphur-poor keratohyalin contains 0-6-0-9% sulphur. It is suggested that the sulphur-rich keratohyalin granules are the source of the peripheral envelope protein of cornified cells.

Sulphur in Different Types of Keratohyalin Granules: A Quantitative Assay by X-Ray Microanalysis

1974 ◽  
Vol 15 (2) ◽  
pp. 359-377
Author(s):  
H. JESSEN ◽  
P. D. PETERS ◽  
T. A. HALL
Keyword(s):  
Envelope Protein ◽  
Quantitative Assay ◽  
Lingual Epithelium ◽  
X Ray ◽  
Sulphur Concentration ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Different Types ◽  
Keratohyalin Granule ◽  
Composite Granules

The elemental composition of keratohyalin granules from the interpapillary and papillary lingual epithelium and the oesophageal epithelium of the rat were studied by X-ray microanalysis in an EMMA-4 analytical electron microscope, equipped with an energy dispersive detector. A quantitative assay of the sulphur concentration in keratohyalin granules was performed, using a suitable sulphur standard. The results demonstrate that different types of keratohyalin granule have different compositions. Single granules - a type of keratohyalin granule present in both nuclei and cytoplasm of the epithelial cells - are rich in sulphur, having a content of 3.6-3.8%. Another type of keratohyalin granule - composite granules - contains a sulphur-rich component and a sulphur-poor component. The sulphur-poor component contains 0.8-1.4% sulphur. It is suggested that the sulphur-rich keratohyalin granules are involved in the deposition of the peripheral envelope protein of cornified cells.

point-Analysis Using the Extrapolation Method in the Analytical Electron microscope

1990 ◽  
Vol 48 (2) ◽  
pp. 430-431
Author(s):  
Zenji Horita ◽  
Ryuzo Nishimachi ◽  
Takeshi Sano ◽  
Minoru Nemoto
Keyword(s):  
Electron Microscope ◽  
Extrapolation Method ◽  
X Ray ◽  
Absorption Correction ◽  
Point Analysis ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Data Points ◽  
Identical Composition ◽  
X Ray Absorption

Absorption correction is often required in quantitative x-ray microanalysis of thin specimens using the analytical electron microscope. For such correction, it is convenient to use the extrapolation method[l] because the thickness, density and mass absorption coefficient are not necessary in the method. The characteristic x-ray intensities measured for the analysis are only requirement for the absorption correction. However, to achieve extrapolation, it is imperative to obtain data points more than two at different thicknesses in the identical composition. Thus, the method encounters difficulty in analyzing a region equivalent to beam size or the specimen with uniform thickness. The purpose of this study is to modify the method so that extrapolation becomes feasible in such limited conditions. Applicability of the new form is examined by using a standard sample and then it is applied to quantification of phases in a Ni-Al-W ternary alloy.The earlier equation for the extrapolation method was formulated based on the facts that the magnitude of x-ray absorption increases with increasing thickness and that the intensity of a characteristic x-ray exhibiting negligible absorption in the specimen is used as a measure of thickness.

Peak-to-background measurements on a 300-kV TEM/STEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1236-1237 ◽  
Author(s):  
S. M. Zemyan ◽  
D. B. Williams
Keyword(s):  
Electron Microscope ◽  
X Ray ◽  
Background Ratio ◽  
Window Method ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Cr Film

As has been reported elsewhere, a thin evaporated Cr film can be used to monitor the x-ray peak to background ratio (P/B) in an analytical electron microscope. Presented here are the results of P/B measurements for the Cr Ka line on a Philips EM430 TEM/STEM, with Link Si(Li) and intrinsic Ge (IG) x-ray detectors. The goal of the study was to determine the best conditions for x-ray microanalysis.We used the Fiori P/B definition, in which P/B is the ratio of the total peak integral to the average background in a 10 eV channel beneath the peak. Peak and background integrals were determined by the window method, using a peak window from 5.0 to 5.7 keV about Cr Kα, and background windows from 4.1 to 4.8 keV and 6.3 to 7.0 keV.

Optimizing Spatial Resolution for X-ray Microanalysis

2001 ◽  
Vol 7 (S2) ◽  
pp. 694-695
Author(s):  
Eric Lifshin ◽  
Raynald Gauvin ◽  
Di Wu
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Spatial Resolution ◽  
Maximum Diameter ◽  
Thin Sections ◽  
X Ray ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Limiting Value ◽  
Made In

In Castaing’s classic Ph.D. dissertation he described how the limiting value of x-ray spatial resolution for x-ray microanalysis, of about 1 μm, was not imposed by the diameter of the electron beam, but by the size of the region excited inside the specimen. Fifty years later this limit still applies to the majority of measurement made in EMAs and SEMs, even though there is often a need to analyze much finer structures. When high resolution chemical analysis is required, it is generally necessary to prepare thin sections and examine them in an analytical electron microscope where the maximum diameter of the excited volume may be as small as a few nanometers. Since it is not always possible or practical, it is important to determine just what is the best spatial resolution attainable for the examination of polished or “as received” samples with an EMA or SEM and how to achieve it experimentally.

Analytical Formulae for Calculation of X-Ray Detector Solid Angles in the Scanning and Scanning/Transmission Analytical Electron Microscope

2014 ◽  
Vol 20 (4) ◽  
pp. 1318-1326 ◽  
Author(s):  
Nestor J. Zaluzec
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Solid Angle ◽  
Analytical Electron Microscopy ◽  
X Ray ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Scanning Transmission ◽  
Analytical Formulae ◽  
Detector Configurations

AbstractClosed form analytical equations used to calculate the collection solid angle of six common geometries of solid-state X-ray detectors in scanning and scanning/transmission analytical electron microscopy are presented. Using these formulae one can make realistic comparisons of the merits of the different detector geometries in modern electron column instruments. This work updates earlier formulations and adds new detector configurations.

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