Showing papers on "Fluorescence spectrometry published in 1980"

Element analysis of skeletal muscle in duchenne muscular dystrophy using x-ray fluorescence spectrometry

Abstract: Concentrations of calcium, iron, copper, and zinc were simultaneously measured by x-ray fluorescence spectrometry in muscle biopsies from 11 normal subjects, 13 patients with Duchenne muscular dystrophy (DMD), and 3 DMD carriers. Calcium and copper levels were significantly elevated in patients with DMD compared to controls, and one presumptive carrier also showed an elevated calcium concentration. Comparisons with morphological data for the same samples showed a significant positive correlation between calcium concentration and the percentage area of type 2 fibers in controls, but no other correlations were found to be significant. These results illustrate the value of x-ray fluorescence spectrometry and provide further evidence for the involvement of calcium in dystrophic processes.

Laser-induced fluorescence spectrometry of polycyclic aromatic hydrocarbons isolated in vapor-deposited n-alkane matrices

Abstract: The analytical utility of fluorescence spectrometry of polycyclic aromatic hydrocarbons matrix isolated in vapor-deposited, annealed n-heptane deposits is considered. Much greater spectral resolution can be obtained in heptane than in conventional (nitrogen or argon) matrices; the possibilities for selective excitation in alkane matrices of fluorescence of individual compounds in multicomponent samples can be exploited effectively only if dye-laser excitation is utilized. In contrast, laser excitation offers few general advantages over lamp excitation for matrix-isolation fluorometry in conventional matrices. The quantitative aspects (linear dynamic range, precision, applicability to mixtures) of matrix-isolation fluorometry in n-alkane media also are discussed. 6 figures.

Molecular fluorescence, phosphorescence, and chemiluminescence spectrometry

Abstract: The survey stresses advances in the techniques of luminescence spectrometry and in instrumentation related to present or potential analytical luminescence methods. Applications are cited only when they appear to be novel. The review, prepared with the assistance of a computer profile of Chemical Abstracts titles prepared locally, covers literature indexed during the period from December, 1979 through October, 1981. Journals received by the end of November, 1981 have been scanned by the author. As in a previous review, certain topics are excluded. These include all publications concerning atomic fluorescence, molecular luminescence in flames, X-ray fluorescence, solid-state phosphor and semiconductor luminescence (both organic and inorganic), radioluminescence, liquid scintillation counting, photosynthesis and solar energy conversions. Papers dealing with luminescence in liquid, thin-layer, or paper chromatography are cited only when they appear to be of appreciable spectroscopic interest. The literature on fluorescent probing of macromolecular and micellar systems has been excluded almost entirely except for citation of a few general reviews. To keep the number of references from becoming unmanageable, a great deal of arbitrary exclusion of interesting work was necessary. 580 references.

Trachelomonas hispida var. coronata (euglenophyceae). iii. envelope elemental composition and mineralization1,2

Abstract: This report is the first direct demonstration of Mn deposition in envelopes (loricas) of Trachelomonas in culture. The envelopes of Trachelomonas hispida var. coronata Lemm. were analyzed for elemental composition by x-ray fluorescence spectrometry (XRF), atomic absorption spectrophotometry (AA), and electron microscopic, energy-dispersive x-ray spectroscopy (EM-EDS). The envelopes contained extensive deposits of manganese (20 to 60 wt. %) and lesser amounts of Si, Ca and either Ba or Ti, the last three together totalling less than 5% by weight. The average amount of Mn per envelope was estimated at 1.5 x 10/sup -10/ g. Traces of Na, K, P, S and Cl were also detectable. Biomineralization of envelopes was studied by comparison of envelope substructure and composition in lightly colored, golden and dark brown envelopes that were isolated by micromanipulation, processed individually or in groups, and analyzed by SEM, TEM, EM-EDS, and scanning transmission EM-EDS (STEM-EDS). Dark envelopes were thicker (1 to 4..mu..m), more ornate and less porous than light envelopes, but the ultrastructure of the two was similar. In both types of envelopes, distribution and thickness of Mn-containing fibrillar to needle-like microcrystallites were similar. However, dark envelopes contained a greater density of granular deposits around the needlelike microcrystallites thanmore » did light envelopes. Dark envelopes contained 2 to 40 times more Mn than did light envelopes, but since envelope mass is proportionately greater, Mn concentrations were similar. Results suggest that the extent of mineralization depends upon the amount of mucilage secreted. Biomineralization studies with Trachelomonas offer the rare advantage that mineral deposition occurs extracellularly, and not within membrane-bound compartments as in many other unicellular model systems.« less

The discrimination and classification of small fragments of window and non‐window glasses using energy‐dispersive x‐ray fluorescence spectrometry

Abstract: Fifty pairs of window/non-window glasses, the samples in each pair being matched in refractive index to the fourth decimal place, have been analysed using energy-dispersive X-ray fluorescence spectrometry The spectra, from 200μg fragments, were compared using a computer based multi-dimensional data processing system Forty-three pairs of glasses were readily discriminated and forty-nine pairs showed significant differences at about the 5% level The spectral data for the 100 glass samples were then examined graphically for trends in the elemental levels between the window and non-window glasses This led to the construction of two linear combinations, namely the peak area ratio (to calcium) of iron with that of magnesium and the peak area of arsenic with refractive index When plotted against each other these linear combinations and a selection rule allowed 95% of the glasses to be correctly classified

Flame emission, atomic absorption and fluorescence spectrometry

Abstract: Six hundred and thirty references are cited in this review. The information in the review is divided into 12 major areas: books, reviews, and bibliographies; fundamental studies in flames; developments in instrumentation; measurement techniques and procedure; flame emission spectrometry; flame atomic absorption spectrometry; flame molecular absorption spectrometry; electrothermal atomization atomic absorption spectroscopy; hydride generation techniques; graphite furnace atomic emission spectrometry; atomic fluorescence spectrometry; and analytical comparisons. (BLM)

X-ray fluorescence analysis without standards of small particles extracted from super-alloys

Abstract: Small amounts of particulate matter electrochemically extrated from super-alloys were accurately analysed by X-ray fluorescence spectrometry with pure element bulk standards. The extracts are less than a few hundred micrograms per square centimeter and are not homogeneous. They are approximated by a thin film on a filter substrate. The penetration of the particulates into the membrane filter on which they are mounted is negligible and no absorption correction for the filter is required. The spectral distribution of the X-ray source used in the calculation was obtained from Kramer's formula with self-absorption correction for the continuum and from measurements of the characteristic line. The intensity-concentration algorithm is based on the fundamental parameter method; the calculation is simplified because no matrix correction is required if the relative intensities are less than or equal to 0.04. The method gives excellent results in chemical analyses.

Application of Activation Techniques to Biological Analysis

Abstract: 1. PRINCIPLES AND MATHEMATICAL FORMULATION The principle of activation analysis is that elements can be made radioactive by exposure to radiations such as neutrons, protons, or high-energy photons. Two physical processes, prompt and delayed, are associated with activation. For example, in the reaction between thermal neutrons and sodium the gamma rays are emitted within 10−12 sec of the absorption of the neutron. Several analytical techniques, such as X-ray fluorescence spectrometry, utilize prompt radiation, but these will not be discussed here. Activation analysis proper is concerned with the delayed event resulting from the decay of the activated nuclide. Thus in the reaction above, sodium-24 is radioactive and decays with a half-life of 15 hr, giving off characteristic beta and gamma radiation and forming stable 24Mg.

Halothane Biotransformation in Anesthetists

Abstract: Serum bromide levels were measured in 115 anesthetists by use of x-ray fluorescence spectrometry. Bromide levels peaked at 184 +/- 21 micron in anesthetists regularly exposed to halothane (n = 20), at 58 +/- 4 micron in anesthetists sporadically exposed to halothane (n = 71), and at 46 +/- 3 micron in nonexposed anesthetists (n = 24). Kinetic studies were carried out in five other anesthetists after ten days of exposure to halothane. Average daily halothane concentration was 19.2 +/- 3.2 ppm; duration of exposure was 3.8 +/- 0.2 hours/day. Mean serum bromide level increased from 40 +/- 4 micron before exposure to 220 +/- 36 micron on the last day of exposure. Serum bromide half-life was 14 +/- 1.7 days. The study demonstrates that anesthetists debrominate halothane in a dose-related fashion. Serum bromide levels achieved, however, were far below those reported to result in clinical bromism.

The Geochemistry of podiform chromite deposits from two ophiolite complexes, Chalkidiki peninsula, Northern Greece

Abstract: The geochemistry of various petrological units from two mafic-ultramafic complexes, from the Chalkidiki peninsula have been studied. These complexes have been tectonically incorporated into the metamorphic country rocks, forming allochtonous bodies bounded by thrust zones. Chromite deposits occur in both complexes. They are highly sheared in the Gomati complex but grade to host dunite in the Vavdos complex. Major oxide contents and trace element abundances have been determined by X-ray fluorescence spectrometry, mineral analyses have been made by electron microprobe. Data on chromite from both complexes reveal that the chromite ores are of metallurgical type in the Wades complex and of refractory type at Gomati. The genetic model proposed relates to extraction of basaltic melt from depleted upper mantle material and its subsequent fractional crystallization. Podiform chromites are an early product of the crystallization of such a basaltic melt. They are intimately associated with a dunite host rock. The structures of the petrological1y different rock units, suggest formation through processes involving an original magmatic environment. This is reinforced by trends for particular minerals in the Vavdos complex. In the Gomati complex, the rocks are extensively serpentinized although various rock types can still be recognized. Amphibolites, at the contacts to the country rocks, show similarities to ocean floor basaltic extrusives. The two mafic-ultramafic have been interpreted as ophiolitic complexes, generated in small ocean basins or maginal seas, and emplaced inot the crust during the Mesozoic.

[The metabolism of halothane under the influence of thiopental, methohexital, etomidate, enflurane and disulfiram under clinical conditions (author's transl)].

Abstract: The biotransformation of halothane is supposed to be the cause of the rare "halothane-hepatitis". Therefore an inhibition of the metabolism of Halothane is of some interest. We used bromide as a metabolite of Halothane and investigated the bromide level of the serum of patients after halothane anaesthesia by means of x-ray fluorescence spectrometry. The induction of anaesthesia with Thiopental, Methohexital and Etomidate had no influence on the bromide level. Likewise the influence of Enflurane on the metabolism of Halothane was not significant. An effective inhibitor in man is Disulfiram. The authors assume, that further information about the toxicity of Halothane metabolites can be gained through further studies of drugs like Disulfiram.