Soft Gluon Suppression of 1/Nc 1/N_{c} Contributions in Color Suppressed Heavy Meson Decays

We discuss the non-factorizable terms in color suppressed (Class II) decays. Our emphasis is on the non-perturbative soft gluon exchange mechanism, which has been previously found to be responsible for the rule of discarding $1/N_{c}$ in the Class I decays. The non-factorizable contribution to the decays $\bar{B}^{0} \rightarrow D^{0} \pi^{0}$ at the tree level is estimated within the light cone QCD sum rule method which combines the technique of the QCD sum rules with the description of the pion in terms of the set of wave functions of increasing twist. We find that the same soft gluon exchange mechanism tends to cancel the $1/N_{c}$ term in the factorized amplitude.Comment: 10 pages, LATEX, no figure

Extreme Outages due to Polarization Mode Dispersion

We investigate the dependence of the bit-error-rate (BER) caused by amplifier noise in a linear optical fiber telecommunication system on the fiber birefringence. We show that the probability distribution function (PDF) of BER obtained by averaging over many realizations of birefringent disorder has an extended tail corresponding to anomalously large values of BER. We specifically discuss the dependence of the tail on such details of the pulse detection at the fiber output as "setting the clock" and filtering procedures.Comment: 3 pages, 1 figure, submitted to Optics Letter

Regge asymptotics and color suppressed heavy meson decays

We discuss a possible generation of color suppressed B-decays amplitudes through a soft final state interaction. As a typical example, we consider in detail the decay $\bar{B}^{0} \rightarrow D^{0} \pi^{0}$ (and also $\bar{B}^{0} \rightarrow 2 \pi^{0}$). We show that in the approximation of the two particle unitarity and at zero order in $\alpha_{s}$ this process can be related to the weak decay $\bar{B}^{0} \rightarrow D^{+} \pi^{-}$ followed by the strong charge exchange scattering in the Regge kinematics. We estimate the amplitude of this process using the light cone QCD sum rule technique and find that it is supppressed as a power of $1/m_{B}$ in comparison to the amplitude generated by the effective non-leptonic Hamiltonian, but remains important for the physical value of $m_{B}$.Comment: 14 pages,Latex,no figure

Why is the B -> eta' X decay width so large ?

New mechanism for the observed inclusive B -> \eta'X decay is suggested. We argue that the dominant contribution to this amplitude is due to the Cabbibo favored b -> \bar{c}cs process followed by the transition \bar{c}c -> \eta'. A large magnitude of the "intrinsic charm" component of \eta' is of critical importance in our approach. Our results are consistent with an unexpectedly large Br(B -> \eta'+X) \sim 10^{-3} recently announced by CLEO. We stress the uniqueness of this channel for 0^{-+} gluonia search.Comment: Comments on a mixing model for intrinsic charm and pre-asymptotic effects and some references are added. Latex, 9 page

Hard diffractive electroproduction, transverse momentum distribution and QCD vacuum structure

We study the impact of the "intrinsic" hadron transverse momentum on the pre-asymptotic behavior of the diffractive electroproduction of longitudinally polarized $\rho$-meson. Surprisingly, we find the onset of the asymptotic regime in this problem to be rather low, Q^2 ~ 10 GeV^2 where power corrections due to the transverse momentum do not exceed 20 % in the amplitude. This drastically contrasts with exclusive amplitudes where the asymptotics starts at much higher Q^2 = 50 - 100 GeV^2. The sources of such unexpected behavior are traced back to some general (the quark-hadron duality) as well as more silent (properties of higher dimensional vacuum condensates) features of QCD.Comment: 27 pages (LaTex), 1 figure (epsfig

Conformal symmetry on the light cone and nonleading twist distribution amplitudes of massive vector meson

A complete set of asymptotic three particle light cone distribution amplitudes of twist 3 and 4 for a transversely polarized massive vector meson built out of massless current quarks is constructed. The method used is based on a modified conformal projectors technique which allows to handle kinematical corrections due to a finite hadron mass. Consequences of our finding for the \rho -meson hard diffractive electroproduction and \gamma \rho \pi form factor are discussed. Our results may imply a breakdown of OPE for some exclusive processes beyond the leading twist level.Comment: Latex, 12 pages, no figure

Комплексное местное лечение бактериального вагиноза

Перспективами дальнейших исследований является изучение действия препаратом вагиклин с целью уменьшения частоты инфекционных осложнений беременности, в том числе преждевременного излития околоплодных вод на фоне вагинита.Перспективами подальших досліджень є вивчення дії препаратом вагіклін з метою зменшення частоти інфекційних ускладнень вагітності, в тому числі передчасного вилиття навколоплідних вод на фоні вагініту.Prospect for further research is the study of the drug Vagiklin to reduce infectious complications of pregnancy, including premature rupture of membranes against vaginitis

Tiotropium versus Salmeterol for the Prevention of Exacerbations of COPD

BACKGROUND Treatment guidelines recommend the use of inhaled long-acting bronchodilators to alleviate symptoms and reduce the risk of exacerbations in patients with moderate-tovery-severe chronic obstructive pulmonary disease (COPD) but do not specify whether a long-acting anticholinergic drug or a β2-agonist is the preferred agent. We investigated whether the anticholinergic drug tiotropium is superior to the β2-agonist salmeterol in preventing exacerbations of COPD. METHODS In a 1-year, randomized, double-blind, double-dummy, parallel-group trial, we compared the effect of treatment with 18 μg of tiotropium once daily with that of 50 μg of salmeterol twice daily on the incidence of moderate or severe exacerbations in patients with moderate-to-very-severe COPD and a history of exacerbations in the preceding year. RESULTS A total of 7376 patients were randomly assigned to and treated with tiotropium (3707 patients) or salmeterol (3669 patients). Tiotropium, as compared with salmeterol, increased the time to the first exacerbation (187 days vs. 145 days), with a 17% reduction in risk (hazard ratio, 0.83; 95% confidence interval [CI], 0.77 to 0.90; P<0.001). Tiotropium also increased the time to the first severe exacerbation (hazard ratio, 0.72; 95% CI, 0.61 to 0.85; P<0.001), reduced the annual number of moderate or severe exacerbations (0.64 vs. 0.72; rate ratio, 0.89; 95% CI, 0.83 to 0.96; P=0.002), and reduced the annual number of severe exacerbations (0.09 vs. 0.13; rate ratio, 0.73; 95% CI, 0.66 to 0.82; P<0.001). Overall, the incidence of serious adverse events and of adverse events leading to the discontinuation of treatment was similar in the two study groups. There were 64 deaths (1.7%) in the tiotropium group and 78 (2.1%) in the salmeterol group. CONCLUSIONS These results show that, in patients with moderate-to-very-severe COPD, tiotropium is more effective than salmeterol in preventing exacerbations. (Funded by Boehringer Ingelheim and Pfizer; ClinicalTrials.gov number, NCT00563381.

Practical recommendations for choosing an immunobiological preparation for the treatment of severe bronchial asthma of T2-endotype

Biological therapy of bronchial asthma (BA) is a modern method of treating severe forms of the disease, that are uncontrolled by traditional pharmacotherapeutic approaches. Currently, 5 monoclonal antibody (AT) preparations are registered in the world for the treatment of severe bronchial asthma (SBA) of the T2 endotype (T2-SBA) – antibodies, binding to immunoglobulin (Ig) E (anti-IgE – omalizumab), interleukin antagonists (IL)-5 (anti-IL-5 – mepolizumab, resizumab) and its receptor (anti-IL-5Rα – benralizumab), as well as antibodies, that selectively bind to the IL-4 and -13 receptor (anti-IL-4 /13Rα – dupilumab). The article presents data on the effectiveness of these drugs in relation to the key characteristics of SBA, formulates clinical and laboratory criteria, the study of which in real practice can potentially predict the likelihood of a clinical response to a particular type of biological therapy. An algorithm is proposed for choosing a targeted therapy strategy for patients with SBA, clinically associated with allergies, for patients with severe non-allergic eosinophilic BA and for patients with eosinophilic BA of a combined phenotype.Биологическая терапия бронхиальной астмы (БА) представляет собой современный метод лечения тяжелых форм заболевания, неконтролируемых при помощи традиционных фармакотерапевтических подходамов. В настоящее время в мире зарегистрированы 5 препаратов моноклональных антител (АТ) для лечения тяжелой бронхиальной астмы (ТБА) Т2-эндотипа (Т2-ТБА) – АТ, связывающие иммуноглобулин (Ig) Е (анти-IgE – омализумаб), антагонисты интерлейкина (IL)-5 (анти-IL-5 – меполизумаб, реслизумаб) и его рецептора (анти-IL-5Rα – бенрализумаб), а также АТ, избирательно связывающиеся с рецептором IL-4 и -13 (анти-IL-4/13Rα – дупилумаб). В статье приведены данные об эффективности указанных препаратов в отношении ключевых характеристик ТБА, сформулированы клинико-лабораторные критерии, при исследовании которых в реальной практике потенциально может быть предсказана вероятность клинического ответа на тот или иной вид биологической терапии. Предложен алгоритм выбора стратегии таргетной терапии для пациентов с ТБА, клинически ассоциированной с аллергией, для больных тяжелой неаллергической эозинофильной БА и для страдающих эозинофильной БА сочетанного фенотип