Determination of coal ash content by the combined x-ray fluorescence and scattering spectrum.

An alternative method is proposed for the determination of the inorganic constituent mass fraction (ash) in solid fuel by the ratio of Compton and Rayleigh X-ray scattering peaks IC/IR subject to the iron fluorescence intensity. An original X-ray optical scheme with a Ti/Mo (or Sc/Cu) double-layer secondary radiator allows registration of the combined fluorescence-and-scattering spectrum at the specified scattering angle. An algorithm for linear calibration of the Compton-to-Rayleigh IC/IR ratio is proposed which uses standard samples with two certified characteristics: mass fractions of ash (Ad) and iron oxide (WFe2O3 ). Ash mass fractions have been determined for coals of different deposits in the wide range of Ad from 9.4% to 52.7% mass and WFe2O3 from 0.3% to 4.95% mass. Due to the high penetrability of the probing radiation with energy E > 17 keV, the sample preparation procedure is rather simplified in comparison with the traditional method of Ad determination by the sum of fluorescence intensities of all constituent elements.

Rapid diagnostics of urinary iodine using a portable EDXRF spectrometer.

A method for urinary iodine diagnostics using a portable energy-dispersion X-ray fluorescent (EDXRF) spectrometer is proposed. The principle of the method consists in excitation of the sample atoms fluorescence by the energy spectrum intentionally formed from the spectrum of an X-ray tube using an optimized X-ray scheme. The optimization by the criterion of the minimum detection limit for L-series iodine fluorescence lines included the calculation of optimal atomic numbers for materials of a re-radiator and a filter, and their thicknesses, the collimation system parameters, and an X-ray tube voltage. Experimentally achieved detection limits were 45 and 75 µg/L by I-Lα and I-Lß lines, respectively, at the theoretically extreme value 30 µg/L. This sensitivity is found to be sufficient for urinary iodine diagnostics in the range from 50 to 200 µg/L. The results obtained from different patients have shown the satisfactory convergence for the iodine concentration determination by Lα and I-Lß fluorescence lines. The simple sample preparation procedure and comparably small sizes of the apparatus allows rapid researches directly in clinical settings.

[The microcirculation in the mesentery of rats and thrombocyte aggregation during hypoglycemic coma]. / Mikrotsirkuliatsiia v bryzheike krys i agregatsiia trombotsitov pri gipoglikemicheskoi kome.

Sensitivity of the rat arterioles to epinephrine was not changed in hypoglycaemic coma (HC). However, a double threshold dose of epinephrine induced a faster and stronger vasoconstriction in the HC. The thrombocyte ADP-inducing aggregation was lowered in the HC. The data obtained can be useful for correction of severe hypoglycaemic cases.

[The reactivity of the mesenteric arterioles to adrenaline in metabolic coma]. / Reaktivnost' arteriol bryzheiki k adrenalinu pri metabolicheskoi kome.

The reactivity of mesoappendix arterioles to applicated epinephrine application was investigated in 2 models of metabolic coma, hypoglycemic and acetonemic. Hypoglycemic coma (HC) was induced by insulin injection (20 IE/kg) i. m. to rats fasting for 18 hours. Acetonemic coma (AC) was induced by i. v. acetone injection (5.5 mmol). The sensitivity of arterioles to applicated epinephrine did not change in HC and increased twofold in AC vs. the control values (p < 0.01). The reaction of arterioles to injection of double threshold dose of epinephrine in HC developed sooner and the degree of vasoconstriction was 41% higher than in controls. In AC the reaction developed two times sooner and the degree of arterioles constriction was 1.5 times higher vs. the control (p < 0.01).

[Possibility of increasing the sensitivity of the fluorescent antibody indirect method in detection of meningococci]. / O vozmozhnosti povysheniia spetsifichnosti nepriamogo metoda fliuorestsiruiushchikh antitel pri obnaruzhenii meningokokkov

It was shown that different representatives of the Neisseria genus had common antigens of protein nature, detected by the immunofluorescent method. Common antigens can be destroyed during treatment of bacterial smears with proteolytic enzymes; with preservation of group-specific antigens this considerably increases the specificity of the fluorescent antibody method in detection of meningococci.