Use of accelerated helium-3 ions for determining oxygen and carbon impurities in some pure materials

Methods are developed for the determination of O impurity in Be and Si carbide and concurrent determination of C and O impurities in Si and W by irradiation with accelerated He-3 ions and subsequent activity measurements of C-11 and F-18 formed from C and O with the aid of a gamma-gamma coincidence spectrometer. Techniques for determining O in Ge and Ga arsenide with radiochemical separation of F-18 are also described

Ion-Pair Chromatography for the Determination of Capreomycin Sulfate Components and Related Substances

Chromatographic methods for the analysis of antibiotic degradation products are widely used to evaluate the quality of medicines. Natural multicomponent antibiotics, such as capreomycin, are the most challenging compounds in terms of developing analytical procedures for related substances. Capreomycin sulfate monographs of the leading pharmacopoeias do not contain specifications for related substances. The key requirement concerns the sum of the main components of capreomycin calculated by normalising the peak areas in the test solution chromatogram. Therefore, it is important to develop an analytical procedure for determining not only the main components but also related substances of capreomycin.The aim of the study was to develop an analytical procedure for determining both the main components (IA, IB, IIA, and IIB) and related substances of capreomycin by ion-pair ultra-high-performance liquid chromatography (UHPLC).Materials and methods. This study examined capreomycin sulfate powder, an active pharmaceutical ingredient (API). Capreomycin sulfate solutions were analysed after artificial degradation (alkaline or acid hydrolysis) to demonstrate the resolution, selectivity, and efficiency of the experimental chromatographic system. The authors used an Agilent 1100 liquid chromatography instrument (Agilent Technologies) and chromatographic columns: Kinetex C18, YMC-Triart С18, ACQUITY UPLC BEH C18, ACQUITY UPLC BEH C8, ACQUITY UPLC BEH Phenyl, and ACQUITY UPLC CSH C18 (experimental procedure) or Acclaim C18, Zorbax SB-C18, and XBridge BEH130 C18 (The International Pharmacopoeia procedure).Results. In contrast to pharmacopoeial procedures, which evaluate only the component composition, the experimental procedure under the selected chromatography conditions can determine both the component composition and related substances of capreomycin. This advantage results from substituting a column packed with 1.7 µm particles for a 5 µm column required for pharmacopoeial procedures. The experimental procedure remains suitable for liquid chromatography instruments with a pressure limit of no more than 400 bar in the gradient elution mode with two mobile phases. According to the efficiency and selectivity evaluation, ACQUITY UPLC BEH C18 columns (150 × 2.1 mm, 1.7 μm) provide optimal peak resolution for capreomycin isoforms and related substances after artificial degradation of capreomycin.Conclusions. This experimental procedure based on ion-pair UHPLC may be used in the production and stability testing of capreomycin medicines to evaluate the API quality by the content of its main components and related substances

Theory of NMR as a local probe for the electronic structure in the mixed state of the high-TcT_c cuprates

We argue that nuclear magnetic resonance experiments are a site-sensitive probe for the electronic spectrum in the mixed state of the high-$T_c$ cuprates. Within a spin-fermion model, we show that the Doppler-shifted electronic spectrum arising from the circulating supercurrent changes the low-frequency behavior of the imaginary part of the spin-susceptibility. For a hexagonal vortex lattice, we predict that these changes lead to {\it (a)} a unique dependence of the $^{63}$Cu spin lattice relaxation rate, $1/T_1$, on resonance frequency, and {\it (b)} a temperature dependence of $T_1$ which varies with frequency. We propose a nuclear quadrupole experiment to study the effects of a uniform supercurrent on the electronic structure and predict that $T_1$ varies with the direction of the supercurrent.Comment: RevTex, 5 pages, 3 figures embedded in the tex

Bicovariant Differential Geometry of the Quantum Group SLh(2)SL_h(2)

There are only two quantum group structures on the space of two by two unimodular matrices, these are the $SL_q(2)$ and the $SL_h(2)$ [9-13] quantum groups. One can not construct a differential geometry on $SL_q(2)$, which at the same time is bicovariant, has three generators, and satisfies the Liebnitz rule. We show that such a differential geometry exists for the quantum group $SL_h(2)$ and derive all of its properties

Deformed Minkowski spaces: clasification and properties

Using general but simple covariance arguments, we classify the `quantum' Minkowski spaces for dimensionless deformation parameters. This requires a previous analysis of the associated Lorentz groups, which reproduces a previous classification by Woronowicz and Zakrzewski. As a consequence of the unified analysis presented, we give the commutation properties, the deformed (and central) length element and the metric tensor for the different spacetime algebras.Comment: Some comments/misprints have been added/corrected, to appear in Journal of Physics A (1996

Magnetization and specific heat of TbFe3(BO3)4: Experiment and crystal field calculations

We have studied the thermodynamic properties of single-crystalline TbFe3(BO3)4. Magnetization measurements have been carried out as a function of magnetic field (up to 50 T) and temperature up to 350K with the magnetic field both parallel and perpendicular to the trigonal c-axis of the crystal. The specific heat has been measured in the temperature range 2-300K with a magnetic field up to 9 T applied parallel to the c-axis. The data indicate a structural phase transition at 192 K and antiferromagnetic spin ordering at 40 K. A Schottky anomaly is present in the specific heat data around 20 K, arising due to two low-lying energy levels of the Tb3+ ions being split by f-d coupling. Below TN magnetic fields parallel to the c-axis drive a spin-flop phase transition, which is associated with a large magnetization jump. The highly anisotropic character of the magnetic susceptibility is ascribed mainly to the Ising-like behavior of the Tb3+ ions in the trigonal crystal field. We describe our results in the framework of an unified approach which is based on mean-field approximation and crystal-field calculations.Comment: 10 pages, 10 figures, 20 references, accepted by Phys. Rev.

Multiparametric quantum gl(2): Lie bialgebras, quantum R-matrices and non-relativistic limits

Multiparametric quantum deformations of $gl(2)$ are studied through a complete classification of $gl(2)$ Lie bialgebra structures. From them, the non-relativistic limit leading to harmonic oscillator Lie bialgebras is implemented by means of a contraction procedure. New quantum deformations of $gl(2)$ together with their associated quantum $R$-matrices are obtained and other known quantizations are recovered and classified. Several connections with integrable models are outlined.Comment: 21 pages, LaTeX. To appear in J. Phys. A. New contents adde

Efficiency of multidisciplinary rehabilitation of patients with breast cancer

The purpose of the study is evaluating the effectiveness of an interdisciplinary integrated approach in the rehabilitation of patients with breast cancer.Цель исследования – оценить эффективность междисциплинарного комплексного подхода в реабилитации пациентов с раком молочной железы