Electron Spin-Lattice Relaxation of doped Yb3+ ions in YBa2Cu3Ox

The electron spin-lattice relaxation (SLR) times T1 of Yb3+‡ ions were measured from the temperature dependence of electron spin resonance linewidth in Y0.99Yb0.01Ba2Cu3Ox with different oxygen contents. Raman relaxation processes dominate the electron SLR. Derived from the temperature dependence of the SLR rate, the Debye temperature (Td) increases with the critical temperature Tc and oxygen content x. Keywords: EPR; ESR; Electron spin-lattice relaxation; Debye temperature; Critical temperatureComment: 5 Pages 4 Figure

Кардиоваскулярные эффекты инкретиномиметиков и их терапевтический потенциал

Antidiabetic drugs with incretin activity in addition to pronounced hypoglycemic activity cause moderate reduction in blood pressure and fat mass as well as improve the lipid profile in patients with type 2 diabetes mellitus (T2DM). In clinical trials the addition of glucagon-like peptide-1 (GLP-1) analogues to standart T2DM therapy leads to significantly reduce the risk of fatal and nonfatal cardiovascular complications. According to the results of many experimental and clinical studies it was shown that GLP-1 analogs protect endothelium in diabetic patients and protect cardiomyocytes after ischemia-reperfusion lesion. Pleiotropic effects of GLP-1-based therapies are realized due to the presence of GLP-1-receptor in endothelial cells, cardiomyocytes, neurons, monocytes and macrophages, as well as due to the connection of the receptor with the most important intracellular signaling cascades (through activation of protein kinase A and B). Whereby GLP-1-based therapies affect the functional condition as well as processes of regeneration and apoptosis of target cells. This review presents the results of studies the cardiovascular effects of GLP-1-based therapies of diabetes. Described proposed nowadays mechanisms of endothelium protective and cardioprotective action of GLP-1 analogs that associated with the action on endothelial function, vascular wall inflammation (the expression of adhesion molecules and inflammatory cytokines), and apoptosis of endothelial cells and cardiomyocytes.Лекарственные препараты с инкретиновой активностью помимо выраженного гипогликемического действия, вызывают умеренное снижение артериального давления, массы жировой ткани и улучшение липидного профиля у пациентов с сахарным диабетом (СД) 2 типа. В клинических исследованиях добавление к терапии СД 2 типа аналогов глюкагоноподобного пептида-1 (ГПП-1) значимо снижало риск развития фатальных и нефатальных сердечно-сосудистых осложнений СД. Также было показано, что аналоги ГПП-1 в условиях СД оказывают эндотелиопротективное, а при ишемически-реперфузионном поражении миокарда кардиопротективное действие. Накопленные к настоящему времени результаты исследований (клинических и с использованием лабораторных животных) позволяют говорить о плейотропных эффектах инкретиномиметиков, в частности кардио- и эндотелиопротективных. Эти эффекты реализуются благодаря наличию рецептора к ГПП-1 на эндотелио- и кардиомиоцитах, нейронах, моноцитах и макрофагах. Также установлена связь данного рецептора с важнейшими внутриклеточными сигнальными каскадами (через активацию протеинкиназы А и B), посредством чего реализуется влияние ГПП-1 на функционирование, а также процессы апоптоза и регенерации клеток-мишеней. В обзоре представлены результаты исследований кардиоваскулярных эффектов инкретиномиметиков в терапии СД, а также предполагаемые механизмы их эндотелио- и кардиопротективного действия. Показано их влияние на функциональное состояние эндотелия, воспаление в сосудистой стенке (экспрессию молекул адгезии и провоспалительных цитокинов), а также апоптоз эндотелио- и кардиомиоцитов

Electron Spin-Lattice Relaxation of Er3+ ions in Er0.01Y0.99Ba2Cu3Ox

The temperature dependence of the electron spin-lattice relaxation SLR was studied in Er0.01Y0.99Ba2Cu3Ox compounds. The data derived from the electron spin resonance ESR and SLR measurements were compared to those from inelastic neutron scattering studies. SLR of Er3+ ions in the temperature range from 20 K to 65 K can be explained by the resonant phonon relaxation process with the involvement of the lowest excited crystalline-electric-field electronic states of Er3+. These results are consistent with a local phase separation effects. Possible mechanisms of the ESR line broadening at lower temperatures are discussed. Keywords: YBCO; EPR; ESR; Electron spin-lattice relaxation time, T ; Crystalline-electric-fieldComment: 6 pages, 4 figure

Measurement of \Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-) and \Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)

The products of the electron width of the J/\psi meson and the branching fraction of its decays to the lepton pairs were measured using data from the KEDR experiment at the VEPP-4M electron-positron collider. The results are \Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-)=(0.3323\pm0.0064\pm0.0048) keV, \Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)=(0.3318\pm0.0052\pm0.0063) keV. Their combinations \Gamma_{ee}\times(\Gamma_{ee}+\Gamma_{\mu\mu})/\Gamma=(0.6641\pm0.0082\pm0.0100) keV, \Gamma_{ee}/\Gamma_{\mu\mu}=1.002\pm0.021\pm0.013 can be used to improve theaccuracy of the leptonic and full widths and test leptonic universality. Assuming e\mu universality and using the world average value of the lepton branching fraction, we also determine the leptonic \Gamma_{ll}=5.59\pm0.12 keV and total \Gamma=94.1\pm2.7 keV widths of the J/\psi meson.Comment: 7 pages, 6 figure

Measurement of RudsR_{\text{uds}} and RR between 3.12 and 3.72 GeV at the KEDR detector

Using the KEDR detector at the VEPP-4M $e^+e^-$ collider, we have measured the values of $R_{\text{uds}}$ and $R$ at seven points of the center-of-mass energy between 3.12 and 3.72 GeV. The total achieved accuracy is about or better than $3.3\%$ at most of energy points with a systematic uncertainty of about $2.1\%$. At the moment it is the most accurate measurement of $R(s)$ in this energy range

Search for narrow resonances in e+ e- annihilation between 1.85 and 3.1 GeV with the KEDR Detector

We report results of a search for narrow resonances in e+ e- annihilation at center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR detector at the VEPP-4M e+ e- collider. The upper limit on the leptonic width of a narrow resonance Gamma(R -> ee) Br(R -> hadr) < 120 eV has been obtained (at 90 % C.L.)

Measurement of main parameters of the \psi(2S) resonance

A high-precision determination of the main parameters of the \psi(2S) resonance has been performed with the KEDR detector at the VEPP-4M e^{+}e^{-} collider in three scans of the \psi(2S) -- \psi(3770) energy range. Fitting the energy dependence of the multihadron cross section in the vicinity of the \psi(2S) we obtained the mass value M = 3686.114 +- 0.007 +- 0.011 ^{+0.002}_{-0.012} MeV and the product of the electron partial width by the branching fraction into hadrons \Gamma_{ee}*B_{h} = 2.233 +- 0.015 +- 0.037 +- 0.020 keV. The third error quoted is an estimate of the model dependence of the result due to assumptions on the interference effects in the cross section of the single-photon e^{+}e^{-} annihilation to hadrons explicitly considered in this work. Implicitly, the same assumptions were employed to obtain the charmonium leptonic width and the absolute branching fractions in many experiments. Using the result presented and the world average values of the electron and hadron branching fractions, one obtains the electron partial width and the total width of the \psi(2S): \Gamma_{ee} =2.282 +- 0.015 +- 0.038 +- 0.021 keV, \Gamma = 296 +- 2 +- 8 +- 3 keV. These results are consistent with and more than two times more precise than any of the previous experiments