On the hyperfine interaction in rare-earth Van Vleck paramagnets at high magnetic fields

An influence of high magnetic fields on hyperfine interaction in the rare-earth ions with non-magnetic ground state (Van Vleck ions) is theoretically investigated for the case of $Tm^{3+}$ ion in axial symmetrical crystal electric field (ethylsulphate crystal). It is shown that magnetic-field induced distortions of $4f$-electron shell lead to essential changes in hyperfine magnetic field at the nucleus. The proposed theoretical model is in agreement with recent experimental data.Comment: 4 pages, no figures, submitted to J. Phys. : Cond. Mat

A geometric interpretation of the spectral parameter for surfaces of constant mean curvature

Considering the kinematics of the moving frame associated with a constant mean curvature surface immersed in S^3 we derive a linear problem with the spectral parameter corresponding to elliptic sinh-Gordon equation. The spectral parameter is related to the radius R of the sphere S^3. The application of the Sym formula to this linear problem yields constant mean curvature surfaces in E^3. Independently, we show that the Sym formula itself can be derived by an appropriate limiting process R -> infinity.Comment: 12 page

Pseudospherical surfaces on time scales: a geometric definition and the spectral approach

We define and discuss the notion of pseudospherical surfaces in asymptotic coordinates on time scales. Thus we extend well known notions of discrete pseudospherical surfaces and smooth pseudosperical surfaces on more exotic domains (e.g, the Cantor set). In particular, we present a new expression for the discrete Gaussian curvature which turns out to be valid for asymptotic nets on any time scale. We show that asymptotic Chebyshev nets on an arbitrary time scale have constant negative Gaussian curvature. We present also the quaternion-valued spectral problem (the Lax pair) and the Darboux-Backlund transformation for pseudospherical surfaces (in asymptotic coordinates) on arbitrary time scales.Comment: 20 page

Role of the mean curvature in the geometry of magnetic confinement configurations

Examples are presented of how the geometric notion of the mean curvature is used for general magnetic field configurations and magnetic surfaces. It is shown that the mean magnetic curvature is related to the variation of the absolute value of the magnetic field along its lines. Magnetic surfaces of constant mean curvature are optimum for plasma confinement in multimirror open confinement systems and rippled tori.Comment: PDFLaTeX, 10 pages, 5 figure

Organ-sparing treatment for primarily disseminated breast cancer with metachronous bilateral involvement

Systemic drug therapy remains first-line treatment for primarily disseminated breast cancer (BC). The problem in the use of local methods to treat BC patients with distant metastases has not been fully solved. The most of investigations presented in the modern literature suggest that patients show significantly better survivals after adjuvant systemic therapy with local exposure of a primary tumor, the main goal of which is its local monitoring. At the same time, the choice of optimal treatments and their sequence and combination remain to be explored. The paper describes a case of successful organ-sparing chemoradiation therapy for primarily disseminated BC with metachronous bilateral involvement

Multidimensional Toda type systems

On the base of Lie algebraic and differential geometry methods, a wide class of multidimensional nonlinear systems is obtained, and the integration scheme for such equations is proposed.Comment: 29 pages, LaTeX fil

Observation of Multi-Gap Superconductivity in GdO(F)FeAs by Andreev Spectroscopy

We have studied current-voltage characteristics of Andreev contacts in polycrystalline GdO$_{0.88}$F$_{0.12}$FeAs samples with bulk critical temperature ${T_c}$ = (52.5 \pm 1)K using break-junction technique. The data obtained cannot be described within the single-gap approach and suggests the existence of a multi-gap superconductivity in this compound. The large and small superconducting gap values estimated at T = 4.2K are {\Delta}L = 10.5 \pm 2 meV and {\Delta}S = 2.3 \pm 0.4 meV, respectively.Comment: 5 pages, 4 figures, submitted to JETP Letter

Investigation of LiFeAs by means of "Break-junction" Technique

In our tunneling investigation using Andreev superconductor - normal metal - superconductor contacts on LiFeAs single crystals we observed two reproducible independent subharmonic gap structures at dynamic conductance characteristics. From these results, we can derive the energy of the large superconducting gap $\Delta_L=(2.5 \div 3.4)$ meV and the small gap $\Delta_L=(0.9 \div 1)$ meV at $T = 4.2$ K for the $T_C^{local} \approx (10.5 \div 14)$ K (the contact area critical temperature which deviation causes the variation of $\Delta_L$). The BCS-ratio is found to be $2\Delta_L/k_BT_C = (4.6 \div 5.6)$, whereas $2\Delta_S/k_BT_C \ll 3.52$ results from induced superconductivity in the bands with the small gap.Comment: 7 pages, 5 figures. Published in Pis'ma v ZhETF 95, 604-610 (2012

СРАВНИТЕЛЬНЫЙ АНАЛИЗ РЕЗУЛЬТАТОВ КОМПЛЕКСНОГО ЛЕЧЕНИЯ МЕСТНОРАСПРОСТРАНЕНОГО РАКА МОЛОЧНОЙ ЖЕЛЕЗЫ С ИСПОЛЬЗОВАНИЕМ УСКОРЕНОГО И КОНВЕНЦИОНАЛЬНОГО РЕЖИМОВ ОБЛУЧЕНИЯ

Results of treatment of 172 patients with locally advanced breast cancer (stage III) who received a radical course of radiotherapy as a component of comprehensive treatment are presents. In the study group A patients (n=66) received accelerated course radiotherapy (daily dose 3 Gy, given in 2 fraction 1,5 Gy with interval 5–6 hours). Total dose on the sternal and subclavian zone was 51 Gy (60 units TDF) and to the breast 60 Gy (70 units TDF). Patients of the control group (n=106) received the conventional radiotherapy (2 Gy, 5 times a week, total dose 60 Gy). Complete regression of tumors in the study group A was revealed in 25,7 % of cases, in the control group B only in 0,9 % of patients (p<0,001). Five-year overall survival with accelerated radiotherapy has increased on 18,7 % in comparison with conventional regimen (p <0,02).Представлены результаты лечения 172 больных местнораспространенным раком молочной железы, получивших радикальный курс фотонной лучевой терапии в качестве компонента комплексного лечения. В основной группе (n=66) облучение проводилиускоренным курсом (1,5 Гр 2 раза в день с интервалом 5–6 ч), СОД на стернальную и подключичную зоны – 51 Гр (изоэффективно 60 Гр), на молочную железу – 60 Гр (изоэффективно 70 Гр). Больным контрольной группы (n=106) проводили  конвенциональную лучевую терапию (РОД 2 Гр, 5 раз в нед, СOД 60 Гр). Полная регрессия опухоли в основной группе отмечена в 25,7 %, в контрольной – в 0,9 % случаев (р<0,001). Пятилетняя общая выживаемость при использовании ускоренного курса лучевой терапии возросла на 18,7 % по сравнению с конвенциональным облучением (p<0,02)