Determination of roxythromycin in blood serum by liquid chromatography with mass spectrometric detection

A procedure has been developed for the determination of a macrolide antibiotic roxythromycin (RX) in blood serum using HPLC with mass spectrometric detection using clarithromycin (CL) as the internal standard. RX and CL have been extracted from the samples by solid-phase extraction in a cartridge filled with a polar adsorbent, cyanopropylsilyl silica gel. The absolute recoveries of RX and CL are 89.6 and 92.5%, respectively. Chromatographic separation has been performed on a Nucleodur C₁₈ Isis column with the mobile phase composed as follows: water-methanol-acetonitrile-formic aid (499: 250: 250: 1 by volume). Registration has been performed in the mode of selected ion monitoring with m/z 837.7 (RX) and m/z 748.7 (CL). The analytical range for RX is 0.097–14.81 μg/mL, the quantification limit is 0.097 μg/mL, the detection limit is 0.03 μg/mL, and the intraday and interday relative standard deviation are 2–6 and 4–8% respectively. The procedure has been applied to the pharmacokinetic studies of the Rulid pharmaceutical preparation.     

Production of High-Transverse-Momentum Deuterons and Tritons at an Angle of 40 $${{}^{\circ}}$$ in Proton–Nucleus Interactions at a Beam Energy of 50 GeV

Physics of Atomic Nuclei - Data on the production of positively charged particles emitted at an angle of 40 $${}^{\circ}$$ (in the laboratory frame) with transverse momenta of up to 2.7 GeV $$/c$$...     

Cross sections of large-angle hadron production in proton– and pion–nucleus interactions III: tantalum nuclei and beam momenta from ±3 GeV/c to ±15 GeV/c

We report on double-differential inclusive cross sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% λ _abs thick stationary tantalum target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20°<θ<125°. They are of particular relevance for the optimization of the design parameters of the proton driver of a neutrino factory.     

Mechanism of photoinduced changes in the optical constants in chalcogenide glass based on As-Se

A model of multicharge centers is proposed. Multicharge local centers are due to negatively charged As atoms in a twin coordination and positively charged Se atoms in a triple coordination. The change in the charge state of these centers because of capture of the light-generated non-equilibrium charge carriers depends on the temperature. Within the framework of this model, three reversing components of the permanent optical memory and the behavior of the low-temperature components at temperatures above the erasure temperature are discussed. The model agrees with experiments on the partial erasure by laser radiation during a change in its intensity or in the specimen temperature.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 48–52, December, 1978.     

Comparison of Geant4 hadron generation with data from the interactions with beryllium nuclei of +8.9 GeV/c protons and pions and −8.0 GeV/c pions

Hadron generation in the Geant4 simulation tool kit is compared with inclusive spectra of secondary protons and pions from the interactions with beryllium nuclei of +8.9 GeV/c protons and pions, and of −8.0 GeV/c pions. The data were taken in 2002 at the CERN Proton Synchrotron with the HARP spectrometer. We report on significant disagreements between data and Monte Carlo simulation especially in the polar-angle distributions of secondary protons and pions. On leave of absence at Ecole Polytechnique Fédérale, Lausanne, Switzerland.     

Knockout of deuterons and tritons with large transverse momenta in <Emphasis Type="Italic">pA</Emphasis> collisions involving 50-GeV protons

Formation of the d and t cumulative light nuclear fragments emitted from the nucleus with large transverse momenta at an angle of 35° in the laboratory frame is investigated. The data on collisions of 50-GeV protons with the C, Al, Cu, and W nuclei are collected using the extracted proton beam of the IHEP accelerator and the SPIN detector. The results indicate that the dominant contribution to formation of nuclear fragments comes from the local process of direct knockout from the nucleus.