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.

[Whole-body diffusion-weighted magnetic resonance imaging by estimating the measurable diffusion coefficient in Hodgkin Iymphoma].

OBJECTIVE: To determine whether the measurable diffusion coefficient (MIC) may be used to differentiate normal and lymphomatosis-altered lymph nodes (LNs) in patients with Hodgkin lymphoma (HL). MATERIAL AND METHODS: Whole-body magnetic resonance (MR) imaging was used to compare the MICs of LNs in 27 apparently healthy individuals and 41 patients with a verified diagnosis of HL. RESULTS: Construction of 95% confidence intervals showed that the MICs of normal LNs were in the range of 1.00 to 1.73 x x10(-3) mm2/sec and significantly higher (p < 0.05) than those of lymphomatosis-affected LNs (MIC, 0.59 to 0.94 x 10(-3) mm2/sec). The cut-off point (for discretization) of normal and lymphomatosis-altered LNs was in the range of 0.94 to 1.00 x 10(-3) mm2/sec. Consequently, the LN with a MIC of less than 0.94 x 10(-3) mm2/sec may be thought of as affected by the lymphomatous process. CONCLUSION: MIC calculation permits differentiation of normal and affected LNs having equal signal characteristics (including those on diffusion-weighted MR images).

[Magnetic resonance imaging in the staging of malignant lymphomas].

Computed tomography, 18FDG-PET and the hybrid FDG-PET/CT are the most commonly used diagnostic tools for the initial staging and treatment response assessment of malignant lymphomas. MRI techniques such as whole-body MRI and diffusion-weighted imaging may become good radiation-free alternatives to FDG-PET/CT. Diffusion-weighted imaging is characterized by high sensitivity for the detection of lesions and allows quantitative assessment of diffusion that may aid in the evaluation of malignant lymphomas. This article will review the value of these emerging MRI techniques for the staging and response assessment of malignant lymphoma.

[Role of children physical development in radiation hygienic monitoring system].

The article deals with longstanding work on studies of physical development parameters among preschoolers aged 4-7 and dwelling on territories near to objects with potential radiation danger, also on radiation-connected anxiety in parents of the examined children. The stated objects when exploited in normal mode were proved to cause no influence on the children's development. Social and economical factors appeared to play leading role in developmental parameters formation. Increased level of radiation-connected anxiety in parents of the children examined appeared to be out of proportion to real favorable radiation background of the territories examined.

Metric similarity of dynamic commutation processes in situ and in vitro.

The dynamics of string growth was studied in model homochiral solutions of biomimetics, trifluoroacetylated amino alcohols (TFAAA) in heptane, water, and inverted heptane-water emulsion. In heptane and water, a thick (~1 µ in diameter) string had a crown of thin strings on its growing terminal and these thin strings effectively adsorbed dissolved TFAAA. In emulsion, the strings grew inside the water droplets, in which this TFAAA cannot be solved, presumably due to transport of TFAAA molecules from heptane into water in the surface layer surrounding the string. Applications of these phenomena to in vivo cell commutation were discussed.

Effects of physicochemical forms of phenazepam and Panavir on their action at ultra-low doses.

A concept of physicochemical forms of biologically active substances introduced in investigation of the action mechanism of ultra-low doses allows qualitative explanation of the main effects of ultra-low doses, chemical diversity of biologically active substances, and physical boundaries for these effects. Phenazepam was shown to possess activity in ultra-low doses only in disperse state, in the form of nanoparticles with a diameter <100-300 nm; these nanoparticles appear as micelles of surface active substances and solvated. Panavir possesses pharmacological activity in ultra-low doses and appears as nanoparticles with a diameter of 200-300 nm, which have uncompensated negative surface charge and polymer nature.

[Mental and physical development of children living in the area of monitoring pollution from a plant for processing and long-term storage of radioactive waste].

Environmental conditions in the area hosting a plant for processing and long storage of low- to moderately-active radioactive waste are described as reasonably safe. Residence in the area does not exert negative influence on the physical and mental development of children. Several indicators of physical development give better estimates than at the control territory. The difference can be accounted for by a better social situation in the study area (housing conditions, financial standing, food patterns, general lifestyle).

[Children's physical and mental development in the Moscow North-Western Administrative District].

The paper gives development quotients in 5-6-year-old children from the North-Western Administrative District of Moscow, which were obtained from the survey made in 2005. Only 41.9% of the boys and 30.7% of the girls were ascertained to have no physical developmental deviations. The major problem of childhood development is the underdevelopment of the functional parameters of the locomotor apparatus and respiratory system. The physical development is significantly worse in the girls than that in the boys in the majority of integral indices.

Double ionization of lithiumlike ions by Compton scattering of high-energy photons.

The double ionization of lithiumlike ions by Compton scattering of photons is investigated in the asymptotic high-energy region. To leading order of the nonrelativistic perturbation theory, the total cross section for double Compton effect is calculated, taking into account the channels of simultaneous and sequential emission of two electrons. Relationships between the cross sections for double ionization of He- and Li-like ions with the same nuclear charge Z are established. This can open wide perspectives for experimental investigations of ionization processes involving low-lying excited states. The universal scaling is found for the ratio of double-to-single ionization in the lithium isoelectronic sequence.

[Parameters of physical and mental development of children and adolescents residing near enterprise for radioactive waste processing and stationary storage].

Operation of enterprise for radioactive waste processing and disposal does not influence negatively physical and mental development of children and adolescents residing in the area under observation. In some parameters, physical and mental development of children and adolescents residing in the area under observation surpasses that in reference area--that could be due to social and economic peculiarities.

[Fractures of the apex of the orbit in injuries of facial bones]. / Perelomy vershiny glaznitsy pri povrezhdeniiakh kostei litsa.

Thirty patients with fractures of the apex of the orbit were examined by clinical and x-ray methods. The types of fractures of facial skull bones were specified, which were aggravated by the patients state, as was the type of injuries to osseous structures participating in the formation of the orbital apex. A purposeful x-ray examination of the orbital apex in patients with injuries to facial bones helps to rule out undervaluation of the severity of injury which can be assessed only on the basis of clinical signs. Use of a modified panoramic sonography for examination of the apex of the orbit in accordance with the standard program of Sonark device for the examination of orbital nerve canals helps assess the nature of injuries to bone structures in this area.

Origin of amphiphilic molecules and their role in primary structure formation.

Attempts to solve two fundamental questions are described: the first concerns which mechanisms were responsible for the self-assembly of membrane structures on the prebiotic Earth, and the second concerns the routes by which considerable amounts of membrane amphiphiles formed from simpler hydrocarbons. The physicochemical properties of several amphiphilic compounds extracted from the Murchison carbonaceous chondrite were studied, using infra-red and fluorescent spectroscopy, measurements of surface activity, chromato-mass spectrometry, and polarization and electron microscopy. The results supported previous observations that amphiphilic and aromatic hydrocarbons were present in significant quantities, and the first demonstration of surface activity among a number of acidic derivatives of hydrocarbons is reported. In addition, one fraction of the surface-active compounds can form bilayer structures, showing that membranes could have self-assembled on the prebiotic Earth. Photochemical oxidation of hydrocarbons is shown to be a likely source of the amphiphilic molecules required for the self-assembly of primary membrane structures.

[Subcellular changes in the cortex of the motor analyzer and hippocampus of dogs with locally manifested neuroses]. / Subkletochnye izmeneniia v kore dvigatel'nogo analizatora i gippokampa sobak pri nevroze s lokal'nym proiavleniem.

In experiments on dogs with local neurosis-continuous flexion of the foreleg-changes were revealed in the beta-rhythm amplitude and the frequency of mean unit activity in the motor cortex, and the appearance and increased amplitude of the theta-rhythm in the hippocampus. Specific activity of Na+-K+-activated, and Mg2+-dependent ATPase decreases in subcortical fractions of the experimental animals' cerebral cortex by 55.0% in the synaptic membranes and 2 to 2.5 times in light and heavy synaptosomes, respectively. In similar fractions of the dorsal hippocampus, the activity of the enzyme decreases by 30.0% in the synaptic membranes and increases by 16.6% in the light synaptosomes and by 6.6% in the heavy ones.

Free radical label: new approach to the study of super-slow molecular dynamics of lipid systems.

A new method of EPR-spectroscopy, the recombination of free radicals appearing as a result of indirect radiolysis of biological molecules after a low temperature irradiation, was applied to the study of molecular dynamics of dimyristoyl phosphatidylcholine in mass and in the structure of liposomes above and below the transition temperature. It was shown that the mobility of lipid molecules in crystalline liposomes was lower than in the structure of liquid-crystalline liposomes. The addition of cholesterol in liposome membranes decreased the lateral molecular motion of lipids in crystalline and liquid-crystalline states; in the latter case, the effect of cholesterol addition was more pronounced. The activation energy for the displacement of the fragments of lipid molecules and the lipid molecule as a whole was estimated, and it was shown that the lipid matrix possesses a high degree of heterogeneity. The solubility of oxygen in the lipid bilayer and the mechanism of lipid diffusion are discussed.

[Free-radical label--new approach to the study of dynamics of lipid systems]. / Svobodnorakikal'nais metka--novyi podkhod k issledovaniiu dinamiki lipidnykh sistem.

A new method of EPR-spectroscopy--the recombination of free radicals appearing as a result of indirect radiolysis of biological molecules after a low temperature irradiation--is applied to the study of molecular dynamics of phosphatidylcholine dimyristoyl in mass and in the structure of liposomes above and below the transition temperature. It was shown, that the mobility of lipid molecules in crystalline liposomes is higher than in the structure of liquid-crystalline liposomes. The addition of cholesterol in liposome membranes decreases the lateral molecular motion of lipids in crystalline and liquid-crystalline state, in the latter case the effect of cholesterol addition is more pronounced. The activation energy for the displacement of the fragments of lipid molecules and the lipid molecule as a whole was estimated, and it was shown, that lipid matrix possesses a high degree of heterogeneity.