Investigation of heavy-heavy pseudoscalar mesons in thermal QCD Sum Rules

We investigate the mass and decay constant of the heavy-heavy pseudoscalar, $B_c$, $\eta_c$ and $\eta_b$ mesons in the framework of finite temperature QCD sum rules. The annihilation and scattering parts of spectral density are calculated in the lowest order of perturbation theory. Taking into account the additional operators arising at finite temperature, the nonperturbative corrections are also evaluated. The masses and decay constants remain unchanged under $T\cong 100 ~MeV$, but after this point, they start to diminish with increasing the temperature. At critical or deconfinement temperature, the decay constants reach approximately to 35% of their values in the vacuum, while the masses are decreased about 7%, 12% and 2% for $B_c$, $\eta_c$ and $\eta_b$ states, respectively. The results at zero temperature are in a good consistency with the existing experimental values as well as predictions of the other nonperturbative approaches.Comment: 11 Pages, 2 Tables and 6 Figure

Bethe-Sommerfeld conjecture for periodic operators with strong perturbations

We consider a periodic self-adjoint pseudo-differential operator $H=(-\Delta)^m+B$, $m>0$, in $\R^d$ which satisfies the following conditions: (i) the symbol of $B$ is smooth in \bx, and (ii) the perturbation $B$ has order less than $2m$. Under these assumptions, we prove that the spectrum of $H$ contains a half-line. This, in particular implies the Bethe-Sommerfeld Conjecture for the Schr\"odinger operator with a periodic magnetic potential in all dimensions.Comment: 61 page

Scalar Quarkonia at Finite Temperature

Masses and decay constants of the scalar quarkonia, $\chi_{Q0} (Q=b,c)$ with quantum numbers $I^G(J^{PC})=0^{+}(0^{++})$ are calculated in the framework of the QCD sum rules approach both in vacuum and finite temperature. The masses and decay constants remain unchanged up to $T\simeq100~MeV$ but they start to diminish with increasing the temperature after this point. At near the critic or deconfinement temperature, the decay constants reach approximately to 25% of their values in vacuum, while the masses are decreased about 6% and 23% for bottom and charm cases, respectively. The results at zero temperature are in a good consistency with the existing experimental values and predictions of the other nonperturbative approaches. Our predictions on the decay constants in vacuum as well as the behavior of the masses and decay constants with respect to the temperature can be checked in the future experiments.Comment: 12 Pages, 9 Figures and 2 Table

Leptonic Decay Constants of DsD_{s} and BsB_{s} Mesons at Finite Temperature

In the present work, $D_{s}$ and $B_{s}$ meson parameters are investigated in the framework of thermal QCD sum rules. The temperature dependence of the mass and the leptonic decay constants are investigated by using Borel transform sum rules and Hilbert moment sum rules. To increase sensitivity, the vacuum contributions are subtracted from thermal expressions and the temperature dependences of the leptonic decay constants and meson masses are studied.Comment: 9 pages, 1 table, 4 figure

Комплексный подход к профилактике развития отсроченной функции почечного трансплантата

Objective: to determine the efficacy and safety of an integrated strategy aimed at preventing delayed renal graft function (DGF).Materials and methods. From June 2018 to December 2022, 478 deceased-donor kidney transplants were performed at Botkin Hospital, Moscow. The patients were divided into two groups: Group I consisted of 128 patients who did not use the integrated strategy; Group II included 67 patients in whom the DGF prevention strategy was used at the perioperative stage. The integrated strategy involved the use of hypothermic oxygenated machine perfusion (HOPE) using expanded criteria donors, the use of a second warm ischemia (SWI) elimination device, personalized initial calcineurin inhibitor (CI) dosing, and use of alprostadil for high vascular resistance in renal graft arteries.Results. DGF occurred in 5 of 44 patients (11.4%) that used the integrated strategy, and in 13 of 44 patients (29.5%) in the control group. The differences were statistically significant (p = 0.034), there was a medium strength relationship between the traits (V = 0.225). The use of the integrated DGF prevention approach reduced the chances of developing DGF by a factor of 0.3 (95% CI: 0.1–0.95). The risk of DGF in the integrated strategy group was 61.3% of the risk of DGF in the non-strategy group, thus the relative risk (RR) is 1.63 (95% CI: 1.1–2.4). Median duration of graft function normalization was statistically significantly lower in group II: 5 (IQR: 3–9) versus 15 (IQR: 7–19) days (p = 0.012). Mean length of hospital stay was 19.1 ± 4.2 (95% CI: 14.5–26.1) bed-days in group I and 13.9 ± 3.4 (95% CI: 9.3–17.2) bed-days in group II. Differences in this indicator were also statistically significant (p = 0.043).Conclusion. The set of DGF prevention measures, developed at Botkin Hospital, evidence-based and implemented in clinical practice, can reduce the burden of modifiable risk factors of this complication significantly, thereby improving treatment outcomes for kidney transplant recipients considerably.Цель: определить эффективность и безопасность применения комплексного подхода к профилактике развития отсроченной функции почечного трансплантата.Материалы и методы. С июня 2018-го по декабрь 2022 года в Городской клинической больнице имени С.П. Боткина выполнено 478 трансплантаций почки от посмертного донора. В зависимости от применения комплексного подхода больные были разделены на две группы: I группу составили 128 больных, кому не применялся комплексный подход; во II группу наблюдения были включены 67 больных, кому на периоперационном этапе применялся комплексный подход к профилактике развития отсроченной функции почечного трансплантата. Комплексный подход заключался в применении машинной оксигенированной холодовой перфузии при использовании доноров с расширенными критериями, применении устройства для элиминации вторичной тепловой ишемии, персонализированном подходе к назначению стартовой дозы ингибитора кальциневрина, применении алпростадила при высоком сосудистом сопротивлении в артериях почечного трансплантата.Результаты. Отсроченная функция почечного трансплантата при использовании комплексного подхода к ее профилактике развилась в 5 из 44 наблюдений (11,4%), в контрольной группе – у 13 из 44 пациентов (29,5%). Различия были статистически значимыми (р = 0,034), и между признаками была отмечена связь средней силы (V = 0,225). Использование комплексного профилактического подхода уменьшало шансы развития ОФПТ в 0,3 раза (95% ДИ: 0,1–0,95). Риск ОФПТ при использовании комплексного подхода составил 61,3% от риска развития отсроченной функции при отсутствии ее профилактики, таким образом, ОР = 1,63 (95% ДИ: 1,1–2,4). Медиана длительности нормализации функции трансплантата была статистически значимо ниже во II группе: 5 (IQR: 3–9) против 15 (IQR: 7–19) суток (р = 0,012). Средняя длительность госпитализации в I группе составила 19,1 ± 4,2 (95% ДИ: 14,5–26,1) койко-дня, во II – 13,9 ± 3,4 (95% ДИ: 9,3–17,2) койко-дня. Различия по данному показателю были также статистически значимыми (р = 0,043).Заключение. Разработанный в Боткинской больнице научно-обоснованный и внедренный в клиническую практику комплекс профилактических мер отсроченной функции почечного трансплантата позволяет существенно снизить бремя модифицируемых факторов риска данного осложнения и тем самым значимо улучшить результаты лечения реципиентов почечного трансплантата

Spectral expansion for a nonselfadjoint periodic differential operator

In the paper, we construct the spectral expansion for the differential operator generated in L-2(-infinity,infinity) by an ordinary differential expression of arbitrary order with periodic complex-valued coefficients Lebesgue integrable on bounded intervals