Standing wave approach in the theory of X-ray magnetic reflectivity.

An extension of the exact X-ray resonant magnetic reflectivity theory has been developed, taking into account the small value of the magnetic terms in the X-ray susceptibility tensor. It is shown that squared standing waves (fourth power of the total electric field) determine the output of the magnetic addition to the total reflectivity from a magnetic multilayer. The obtained generalized kinematical approach essentially speeds up the calculation of the asymmetry ratio in the magnetic reflectivity. The developed approach easily explains the peculiarities of the angular dependence of the reflectivity with the rotated polarization (such as the peak at the critical angle of the total external reflection). The revealed dependence of the magnetic part of the total reflectivity on the squared standing waves means that the selection of the reflectivity with the rotated polarization ensures higher sensitivity to the depth profiles of magnetization than the secondary radiation at the specular reflection condition.

Interference phenomena of synchrotron radiation in TEY spectra for silicon-on-insulator structure.

The general matrix theory of the photoelectron/fluorescence excitation in anisotropic multilayer films at the total reflection condition of X-rays has been developed. In a particular case the theory has been applied to explain the oscillation structure of L(2,3) XANES spectra for a SiO(2)/Si/SiO(2)/c-Si sample in the pre-edge region which has been observed by a sample current technique at glancing angles of synchrotron radiation. Remarkably the phase of the oscillations is reversed by a ∼2° angle variation. The observed spectral features are found to be a consequence of waveguide mode creation in the middle layer of strained Si, which changes the radiation field amplitude in the top SiO(2) layer. The fit of the data required the correction of the optical constants for Si and SiO(2) near the Si L(2,3)-edges.

[Sarcomatoid carcinoma of the thymus].

Sarcomatoid carcinomas are rare malignancies composed of epithelial (carcinomatous) and sarcomatous elements. High-grade carcinoma is difficult to diagnose by light optic and immunohistochemical studies. The authors give the data available in the literature on sarcomatoid carcinoma of the thymus and also describe their own observation. Its histological pattern is represented by a combination of carcinomatous and sarcomatous elements with extensive necrotic foci. Immunohistologically, the tumor cells expressed total cytokeratin (AE1/AE3), CD99, and focally epithelial membrane antigen. Some tumor cells were vimentin- and SMA-positive. Markers, such as chromogranin A, bcl-2, bcl-6, S-100 protein and myogenin, were negative.

[Ischemic bone necrosis in Itsenko-Cushing disease]. / Kum vuprosa za iskhemichnite kostni nekrozy pri bolestta na Itsenko--Cushing.

X-ray alterations of the type ischemic osseous necrosis were established in three patients (two females and one male) with Icenko-Cushing disease. In the first case--the haed of femur was unilaterally affected: in the second--bilateral lesions with the same localization; and in the third--a combination of changes in the head of femur and the heads of some metatarsal bones. In all patients, secondary ostheoarthrosis alterations were also observed. The tomographic study enabled the visualization of details, characterizing the stage of the progress of the process. The similarity in the roentgenological images, with a substrate of ischemic osseous necrosis in case of exogenous and endogenous hypercortisolism, provide grounds to admit a similarity in the pathogenesis of those states.

[Principles of selection of the method of treating Itsenko-Cushing disease]. / Printsipy vybora metodov lecheniia bolezni Itsenko-Kushinga.

Various methods for therapy of Icenko-Cushing's disease: radiotherapeutic, surgical and medicinal were evaluated. A total of 184 patients were treated. The authors have been of opinion that therapeutic methods depended on function of the neuroendocrine system and adrenal cortex, e. g. reserpine used after gamma-therapy alone or in combination with unilateral adrenalectomy increased the efficacy of therapy and reduced the time of remission. Parlodel used alone or in combination with chloditan could be used in therapy of early forms of the disease in young patients. Transsphenoidal adenomectomy and proton beam therapy of the hypophysis were recommended in hypophysial adenomas. Proton beam therapy of the hypophysis was an effective method for therapy of patients with diffuse hyperplasia of the adrenal cortex and could be used in diffuse nodular hyperplasia of the adrenal cortex in combination with unilateral adrenalectomy.

Isoforms of Serratia marcescens nuclease. The role of Mg2+ in the hydrolysis mechanism.

Structural and functional differences between isoforms Sm1 and Sm2, a lack of influence of free Mg2+ on the isoform structures, formation of DNA-magnesium complex serving with great probability as a real substrate for the nuclease has been summarized on the basis of experimental data. Mg2+ forming a complex with phosphate groups of DNA are supposed to further increase the electrophilicity of the phosphorus atoms besides causing a conformational change of the substrate.