Density Matrix Kinetic Equation Describing a Passage of Fast Atomic Systems Through Matter

The quantum-mechanical consideration of a passage of fast dimesoatoms through matter is given. A set of quantum-kinetic equations for the density matrix elements describing their internal state evolution is derived. It is shown that probabilistic description of internal dynamics of hydrogen-like atoms is impossible even at sufficiently low energies because of the ``accidental'' degeneracy of their energy levels.Comment: 12 pages, LATEX, submitted to J. Phys.

The electromagnetic effects in Ke4K_{e4} decay

The final state interaction of pions in $K_{e4}$ decay allows one to obtain the value of the isospin and angular momentum zero $\pi\pi$ scattering length $a_0^0$.We take into account the electromagnetic interaction of pions and isospin symmetry breaking effects caused by different masses of neutral and charged pions and estimate the impact of these effects on the procedure of scattering length extraction from $K_{e4}$ decay.Comment: 8 pages,1 figur

The isospin symmetry breaking effects in Ke4K_{e4} decays

The Fermi-Watson theorem is generalized to the case of two coupled channels with different masses and applied to final state interaction in $K_{e4}$ decays. The impact of considered effect on the phase of the $\pi\pi$ scattering is estimated and shown that it can be crucial for scattering lengths extraction from experimental data on $K_{e4}$ decays

Исследование процессов перекисного окисления липидов в хрусталике и тканях при экспериментальном холестериновом атеросклерозе.

Одной из моделей экспериментальной катаракты, является модель холестеринового атеросклероза. Исследование липидного и перекисного обменов, активности антиоксидантных ферментов у кроликов с холестериновым атеросклерозом показало, что введение животным холестерина вызвало активацию процессов свободно-радикального окисления в хрусталике и тканях. Данная модель может быть использована в исследовании и разработке средств ингибирующих катарактогенез; One of models of experimental cataracts is the model of cholesteric atherosclerosis. Research of lipid and peroxide metabolism of antioxidant enzymes and rabbits with cholesterol atherosclerosis showed that the administration of cholesterol to animals caused activation of free radical oxidation processes in the lens and tissues. This model can be used in the research and development of cataractogenesis inhibitory drugs

Determination of ππ\pi\pi scattering lengths from measurement of π+π−\pi^+\pi^- atom lifetime

The DIRAC experiment at CERN has achieved a sizeable production of $\pi^+\pi^-$ atoms and has significantly improved the precision on its lifetime determination. From a sample of 21227 atomic pairs, a 4% measurement of the S-wave $\pi\pi$ scattering length difference $|a_0-a_2| = (.0.2533^{+0.0080}_{-0.0078}|_\mathrm{stat}.{}^{+0.0078}_{-0.0073}|_\mathrm{syst})M_{\pi^+}^{-1}$ has been attained, providing an important test of Chiral Perturbation Theory.Comment: 6 pages, 6 figure

Detection of π+π−\pi^+\pi^-atoms with the DIRAC spectrometer at CERN

The goal of the DIRAC experiment at CERN is to measure with high precision the lifetime of the $\pi^+\pi^-$ atom ($A_{2\pi}$), which is of order $3\times10^{-15}$ s, and thus to determine the s-wave $\pi\pi$-scattering lengths difference $|a_{0}-a_{2}|$. $A_{2\pi}$ atoms are detected through the characteristic features of $\pi^+\pi^-$ pairs from the atom break-up (ionization) in the target. We report on a first high statistics atomic data sample obtained from p Ni interactions at 24 GeV/$c$ proton momentum and present the methods to separate the signal from the background.Comment: 19 pages, 12 figures, 1 tabl

The role of the free radical oxidation processes in the development of experimental diabetic cataract

Одной из основных моделей сахарного диабета в эксперименте является аллоксоновая модель. Катарактогенное действие аллоксана как препарата, вызывающего диабет и диабетическую катаракту, связывают с его свободнорадикальным воздействием на белки хрусталика. Обнаружение участия свободнорадикального окисления в возникновении диабета и диабетической катаракты может быть основанием для исследования противокатарактальных свойств природных и синтетических антиоксидантов на развитие экспериментальной диабе¬тической катаракты у крыс с аллоксановым диабетом; One of the main models of diabetes in the experiment is alloxan model. Cataractogenic effect of al¬loxan as a drug which causes diabetes and diabetic cataract is associated with its free-radical effect on the proteins of the lens. Detection of involvement of free radical oxidation in the occurrence of diabetes and diabetic cataract was the basis for the study of anticataract properties of natural and synthetic antioxidants on development of experimental diabetic cataract in rats with alloxan diabetes

First measurement of the π+π−\pi^+\pi^- atom lifetime

The goal of the DIRAC experiment at CERN (PS212) is to measure the $\pi^+\pi^-$ atom lifetime with 10% precision. Such a measurement would yield a precision of 5% on the value of the $S$-wave $\pi\pi$ scattering lengths combination $|a_0-a_2|$. Based on part of the collected data we present a first result on the lifetime, $\tau=[2.91 ^{+0.49}_{-0.62}]\times 10^{-15}$ s, and discuss the major systematic errors. This lifetime corresponds to $|a_0-a_2|=0.264 ^{+0.033}_{-0.020} m_{\pi}^{-1}$.Comment: 18 pages, 6 figure