PubMed · 9170941
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T Majima, H Shimizu, T Tomie, T Kanayama, M Yamada. 1997. [X-ray microscope].. https://pubmed.ncbi.nlm.nih.gov/9170941/
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OBJECTIVE/HYPOTHESIS: The objective of this study was to evaluate the morphological and microchemical changes that affect sclerotic stapes in otospongiosis and van der Hoeve syndrome. METHODS: A scanning electron microscope equipped with an energy-dispersive x-ray analyzer was used in the experiments. RESULTS: In otosclerosis, focal lesions are poorly mineralized, with low calcium salt and reduced calcium-to-phosphorus (Ca/P) ratio (1.9:1). This finding correlates with a spongiotic type of lesion and indicates unstable mineralization with possible change from hydroxyapatite to calcium triphosphate. In van der Hoeve syndrome the presence of magnesium in stapes suggests osteoclastic function stimulation. The osteoclasts secrete many protons, causing an acidified microenvironment. Brushite is formed, and Ca/P ratio decreases in comparison with that of control patients (2.0:1 vs. 2.6:1).
Since silicone has rapidly become one of the most commonly used prosthetic materials in the last 30 years in modern medicine, we have consequently been witnessing more silicone-related disease. Especially after silicone breast implantation, defects in the breast implant have led to serious complications, whereas complications of silicone prosthesis implantation in other body parts are less frequent. Here we present an unusual clinical presentation of a silicone granuloma in a patient with a 27-year history of a wide excision of a melanoma of the right lower extremity and subsequent soft-tissue reconstruction using a silicone device.
The determination of low-Z elements such as carbon, nitrogen, and oxygen in atmospheric aerosol particles is of interest in studying environmental pollution. Conventional electron probe microanalysis technique has a limitation for the determination of the low-Z elements, mainly because the Be window in an energy-dispersive X-ray (EDX) detector hinders the detection of characteristic X-rays from light elements. The feasibility of low-Z element determination in individual particles using a windowless EDX detector is investigated. To develop a method capable of identifying chemical species of individual particles, both the matrix and the geometric effects of particles have to be evaluated. X-rays of low-Z elements generated by an electron beam are so soft that important matrix effects, mostly due to X-ray absorption, exist even within particles in the micrometer size range. Also, the observed radiation, especially that of light elements, experiences different extents of absorption, depending on the shape and size of the particles. Monte Carlo calculation is applied to explain the variation of observed X-ray intensities according to the geometric and chemical compositional variation of individual particles, at different primary electron beam energies. A comparison is carried out between simulated and experimental data, collected for standard individual particles with chemical compositions as generally observed in marine and continental aerosols. Despite the many fundamental problematic analytical factors involved in the observation of X-rays from low-Z elements, the Monte Carlo calculation proves to be quite reliable to evaluate those matrix and geometric effects. Practical aspects of the Monte Carlo calculation for the determination of light elements in individual particles are also considered.