Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Electron Probe Microanalysis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,117 records · Page 62Linked to original sources
PubMed1980

Artifacts in energy dispersive x-ray spectrometry in the scanning electron microscope (II).

The quality of x-ray spectra obtained with an energy dispersive x-ray spectrometer on an electron beam instrument can be severely compromised by the presence of electromagnetic interference. Sources of electromagnetic interference include ground currents and signals generated by time-varying currents in instrument components such as scan coils. Spectrometer resolution can be degraded by the accumulation of ice and vaccum oil on critical components of the device. Operation at high electron energy can cause artifacts in spectra due to direct entry of electrons and spurious x-rays into the detector. Processing high energy photons (above 40 keV) can lead to detector saturation effects which degrade resolution and affect dead time correction. Transmission of high energy x-rays through the detector accompanied by Compton scattering can lead to a distortion of the low energy portion of the spectrum.

Electromagnetic Fields↗
PubMed1994

[Comparative electron microscopic studies on the localization of silicon in leaves of two different grass species].

The quality of green fodder can be diminished by lignifying and mineralizing the plant cell walls. In many grasses epidermal cell walls are penetrated with silica; those plants are extremely rough and sharp-edged and are not ingested by animals. The process of silicification of cell walls was studied comparatively in two grasses, the soft Perennial Ryegrass (Lolium perenne) and the rough Tufted Hair-grass (Deschampsia caespitosa). In Lolium only the epidermal cell walls of the leaf edges and the trichomes are penetrated with silica, whereas in Deschampsia silica could be demonstrated in the walls of all epidermal cells and of the trichomes. In addition, silica containing cells, the so called silica bodies, were found in Deschampsia leaves. Silica was detected using two analytical electron-microscopical techniques, the Electron-Energy-Loss-Spectroscopy (EELS) and the Electron-Spectroscopic-Imaging (ESI).

Animal Feed↗
PubMed1993

[An ultrastructural analysis of the peritubular dentin and of the tubular lumen in healthy teeth].

In this study the authors examined some specimens of fractured dentine of embedded healthy teeth, of people aged between 20 and 30. Connecting the scanning electron microscopy to a system of computerised analysis of spectrometry (EDS) allowed the analysis of the qualitative composition of the specimens. Therefore, the authors described the tubular structure of the sound, the peri- and the intertubular dentine, the winding course of the dentinal tubules and in some specimens, the presence of cylindrical structures inside the tubules. The EDS analysis demonstrated that these tubular structures have the same composition as the intertubular dentine. Former studies described hollow cylindrical structures having a similar morphology solely as a response of the odontoblasts to white spots. On the contrary, in this study it was demonstrated that it is possible to find cylindrical structures which are definitely mineralized in sound teeth without caries. However, the presence of such formations is not concomitant with the disappearance of peritubular dentine which is a typical structural modification of the pathological advancement of the carious lesion.

Adult↗
PubMed1995

Calcium in pollen-pistil interaction in Petunia hybrida Hort. III. Localization of Ca2+ ions and Ca(2+)-ATPase in pollinated pistil.

Studies were carried out of CA2+ and CA(2+)-ATPase localization in pollinated (6 and 48 h after pollination) pistils of Petunia hybrida. The results were confronted with CA2+ localization in mature pollen grain and in unpollinated pistil. It has been found that after pollination the number of CA2+ sequestered in the stigmal exudate and in the sporoderm of the pollen grain gets lower. That phenomenon was associated with the appearance of a large number of Sb/Ca precipitates in the submembrane cytoplasm of the germinating pollen. In the vacuolized pollen grain, i.e. grown into a pollen tube, there were only a few precipitates. In the pollen tube, CA2+ were found in the organelles of the tip cytoplasm and in the external pectin cell wall. Studies with the use of 45Ca2+ have revealed that the source of calcium ions incorporated into the pollen tube tip and its pectin wall is the transmitting tract of the style. In the transmitting tract overgrown with pollen tubes, Ca2+ were located in the intercellular matrix and in the transmitting cells. Sb/Ca precipitates occurred in the nuclei, around the secretory vesicles and on the plasmalemma in the transverse walls region. Elevated Ca2+ level was found in degenerating cells (inhibited pollen tubes, transmitting cells, nucellar cells). The progressing degeneration process of the cells of the transmitting tract of the pollinated pistil was associated with a decrease in the activity of plasmalemmal Ca(2+)-ATPase.

Antimony↗
PubMed1996

Effect of surface topography of titanium on surface chemistry and cellular response.

Surface topography plays a critical role in the interaction of dental implants with adjacent tissues. It has been hypothesized that an increase in surface roughness will result in an increase in calcium and phosphorus deposition after immersion in a simulated physiological solution and will increase protein production and calcium uptake by osteoblast-like cells. With the use of a profilometer, titanium samples ground with 600 grit silicon carbide paper were observed to have an average roughness (Ra) value of 0.28 +/- 0.03 micron, whereas titanium samples polished with 0.3 micron Al2O3 exhibited a Ra value of 0.11 +/- 0.01 micron. X-ray photoelectron spectroscopy analyses indicated the presence of calcium, phosphorus, sodium, and chlorine on both surface conditions after immersion in a protein-free physiologic solution. No significant difference in calcium and phosphorus concentrations were observed between the 600 grit or Al2O3 polished titanium samples after immersion in solution. The Ca/P ratio for both 600 grit and Al2O3 polished titanium was in the range of 0.8 to 1.1 after 12 days in solution. The percent protein retained by the rat bone marrow cell layer on both the Al2O3 polished and 600 grit titanium surfaces increased dramatically during the initial 3 days of the study. The 45Ca assays revealed no significant difference in cellular calcification on Al2O3 polished and 600 grit titanium surfaces. For both the Al2O3 polished and 600 grit surfaces, a sharp increase in 45Ca incorporation was observed after 9 days incubation.

Aluminum Oxide↗
PubMedDate not supplied

Scanning electron microscopy and energy dispersive analysis of machined denture base surfaces.

To relate the characteristics of rotary instruments to the surfaces they produce, acrylic resin, Molloplast B, and Novus were investigated with energy dispersive analysis and scanning electron microscopy (secondary and backscatter images) before and after machining. The chemical composition of cutting instruments, material surfaces, and residues was identified. Machined debris embedded in Molloplast B after machining with the Molloplast stone was found to contain a mean lead content of 45%. High concentrations of barium sulphate were discovered on the arbor band-machined surface of Novus. These differences were related to clinically appropriate instrumentation, and, therefore, biocompatibility studies that intimately relate to the in vivo situation should be considered for new materials.

Dental Polishing↗
PubMed1998

Microlithiasis in parotid sialadenosis and chronic submandibular sialadenitis is related to the microenvironment: an ultrastructural and microanalytical investigation.

AIMS: Microlithiasis was investigated in parotid sialadenosis and chronic submandibular sialadenitis to determine if it relates to the glandular microenvironment as has been found experimentally. METHODS AND RESULTS: Semithin sections were stained by a mixture of methylene blue and Azure II followed by basic fuchsin, which stains calcified parts of microliths red and organic parts green, and ultrathin sections were examined electron microscopically and microanalytically. Microliths in sialadenosis were found in periacinar stroma, in which necrotic acinar cells were found, and in parenchyma, and consisted of consolidated organic material with little or no crystalline calcium. Microliths in sialadenitis were found in stroma, particularly around intercalary ducts, in lumina and in parenchyma, and contained much crystalline calcium. Macrophages enclosed some microliths. CONCLUSIONS: The paucity of calcium in microliths in sialadenosis and the abundance in sialadenitis relates to the glandular calcium. The periacinar distribution of microliths in sialadenosis possibly relates to formation in periacinar necrotic debris. The distribution of microliths in sialadenitis around intercalary ducts possibly relates to formation in matrix vesicles formed from atrophic parenchyma, and in lumina to formation in stagnant secretory material. Microliths appear to be scavenged by macrophages. Thus the experimental finding that salivary microlithiasis relates to the microenvironment pertaining in humans.

Calcinosis↗
PubMed1979

Electron probe X-ray microanalysis and cryoultramicrotomy of unstained myocardial sarcoplasmic reticulum, in situ and fragmented.

Myocardial sarcoplasmic reticulum of cats in situ and fragmented sarcoplasmic reticulum (FSR) were analysed using X-ray microanalysis, cryoultramicrotomy and scanning transmission electron microscopy. 2 types of FSR vesicles can be distinguished morphologically and by their different elemental composition especially by different Ca loading. The Ca content of the sarcoplasmic reticulum can also be detected in situ.

Animals↗
PubMed1986

Type distribution of muscle fibres and their ultrastructure related to intracellular elemental composition as revealed by energy dispersive X-ray microanalysis. A study of multicore myopathy.

Four cases of congenital myopathy, two children and two adults, are described whose light-microscopical and ultrastructural findings are consistent with a multicore myopathy. In all cases a hereditary etiology to the disorders is obvious presumably by an autosomal recessive trait. Fibres with central nuclei and multiple minicores was a prominent finding in all cases. Energy dispersive X-ray microanalysis of single muscle fibres revealed a normal intracellular content of elements (sodium, potassium and chlorine). This is in contrast to the findings in some cases of s.c. myotubular myopathy earlier described from our group where content of sodium and chlorine is markedly increased while that of potassium is decreased. It is suggested that in myotubular myopathy membrane dysfunction causing decreased ionic gradients is an important feature of the pathophysiology while in multicore myopathy other mechanisms, as a suggestion related to mitochondrial and myofibrillar function play a more prominent part. From a diagnostic point of view it seems that X-ray microanalysis can be used to differentiate the two conditions.

Adult↗
PubMed1985

X-ray microanalysis of normal human neutrophils, lymphocytes, monocytes and platelets.

Elemental X-ray microanalysis of normal peripheral blood neutrophils, lymphocytes, monocytes and platelets was carried out with a scanning electron microscope fitted with an X-ray analytical system. Each cell type was characterized by its own spectrum. Nucleus containing cells displayed a high phosphorus level, while platelets showed a low peak of this element. The elevated level of sulfur observed in platelets, neutrophils and monocytes may result from their cytoplasmic granules which contain sulfur-rich substances. The highest amount of calcium was detected in the platelets. The results indicate that X-ray microanalysis may be applied for the detection of the elemental content of blood cells.

Blood Platelets↗
PubMed1979

[New data on the presence of submicroscopic crystalline particles in lung dusts].

Investigation of dusts, isolated from the lungs of decreased miners, has contributed much to the elucidation of the pathogenesis of dust-induced. Numerous theoretical and experimental investigations have been carried out in this field, but there are problems, which are still far from being well understood. One of these is the implication of particles less than 0,5 micron, reckoned by many authors among the air contaminators. In this report data are given on the cristal structure of particles, for which electron difraction and X-ray microanalysis have shown that they have the mineral composition of the bed, where the miner has worked.

Bulgaria↗
PubMed1988

Clinical applications of scanning electron microscopy and energy dispersive X-ray analysis in dermatology--an up-date.

Dermatological papers comprising scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis data published 1983 through 1986 in international journals are reviewed, as an update to our 1984 paper on Clinical applications of scanning electron microscopy and X-ray microanalysis in dermatology. The present paper not only deals with a review of recent publications in this area but also presents the application of microincineration to hair and cryosectioned freeze-dried skin specimens. Examples of the increased contrast obtained in hair cross sections are presented and a discussion on the feasibility of microincineration at analysis of hair and skin cross sections is given. Particle probe analysis (EDX: energy dispersive X-ray analysis and PMP: proton microprobe analysis) as applied to hair and skin samples are presented with stress put on the proton probe analysis. The complementarity of EDX and PMP is demonstrated and future applications are suggested.

Animals↗