A high-pressure hydrogen time projection chamber for the MuCap experiment

The MuCap experiment at the Paul Scherrer Institute performed a high-precision measurement of the rate of the basic electroweak process of nuclear muon capture by the proton, $\mu^- + p \rightarrow n + \nu_\mu$. The experimental approach was based on the use of a time projection chamber (TPC) that operated in pure hydrogen gas at a pressure of 10 bar and functioned as an active muon stopping target. The TPC detected the tracks of individual muon arrivals in three dimensions, while the trajectories of outgoing decay (Michel) electrons were measured by two surrounding wire chambers and a plastic scintillation hodoscope. The muon and electron detectors together enabled a precise measurement of the $\mu p$ atom's lifetime, from which the nuclear muon capture rate was deduced. The TPC was also used to monitor the purity of the hydrogen gas by detecting the nuclear recoils that follow muon capture by elemental impurities. This paper describes the TPC design and performance in detail.Comment: 15 pages, 13 figures, to be submitted to Eur. Phys. J. A; clarified section 3.1.2 and made minor stylistic corrections for Eur. Phys. J. A requirement

Measurement of Muon Capture on the Proton to 1% Precision and Determination of the Pseudoscalar Coupling g_P

The MuCap experiment at the Paul Scherrer Institute has measured the rate L_S of muon capture from the singlet state of the muonic hydrogen atom to a precision of 1%. A muon beam was stopped in a time projection chamber filled with 10-bar, ultra-pure hydrogen gas. Cylindrical wire chambers and a segmented scintillator barrel detected electrons from muon decay. L_S is determined from the difference between the mu- disappearance rate in hydrogen and the free muon decay rate. The result is based on the analysis of 1.2 10^10 mu- decays, from which we extract the capture rate L_S = (714.9 +- 5.4(stat) +- 5.1(syst)) s^-1 and derive the proton's pseudoscalar coupling g_P(q^2_0 = -0.88 m^2_mu) = 8.06 +- 0.55.Comment: Updated figure 1 and small changes in wording to match published versio

Measurement of the Rate of Muon Capture in Hydrogen Gas and Determination of the Proton's Pseudoscalar Coupling gPg_P

The rate of nuclear muon capture by the proton has been measured using a new experimental technique based on a time projection chamber operating in ultra-clean, deuterium-depleted hydrogen gas at 1 MPa pressure. The capture rate was obtained from the difference between the measured $\mu^-$ disappearance rate in hydrogen and the world average for the $\mu^+$ decay rate. The target's low gas density of 1% compared to liquid hydrogen is key to avoiding uncertainties that arise from the formation of muonic molecules. The capture rate from the hyperfine singlet ground state of the $\mu p$ atom is measured to be $\Lambda_S=725.0 \pm 17.4 s^{-1}$, from which the induced pseudoscalar coupling of the nucleon, $g_P(q^2=-0.88 m_\mu^2)=7.3 \pm 1.1$, is extracted. This result is consistent with theoretical predictions for $g_P$ that are based on the approximate chiral symmetry of QCD.Comment: submitted to Phys.Rev.Let

Features of the functional activity of macrophage link of immunity with gastroesophageal reflux disease depending on the type of reluctate: in vitro model

Aim. A generalized analysis of changes in functional activity of macrophages on the basis of phagocytic activity, cytokine profile, changes in the level of expression of surface markers characteristic of pro - or anti-inflammatory phenotype of the cells when exposed to reluctate. Materials and methods. Developed in vitro model of co-peritoneal macrophages of mice With57/BL6 (n=65) and reluctate patients with gastroesophageal reflux disease (GERD; n=65) having different pH values (three group comparison). Took into account the standard criteria phagocytic ability (absorption Staphylococcus aureus 9198, light microscopy), secretory activity (cytokine profile Th1/Th2, flow cytometry) and receptor characterization of macrophages (expression of CD25/80/163/206, flow cytometry). Results. The phagocytic activity of macrophages, calculated on the basis of the average number of bacteria ingested by one phagocyte, is not associated with the pH value of the added reluctate. It is established that the alkalinisation of reluctate leads to significant alteration in the expression of CD receptors - decrease M1 and increase M2. The index of total production of Th1/Тһ2 in groups progressively decreased with increasing pH of reluctate and amounted to 3.6 units in the group pH from 4.6 to 6.6; 2.8 units group a pH of 6.7-7.2 and 1.6 units in the group pH of 7.3 to 8.1, due to increased production of Th2 cytokines at offset reluctate pH to slightly alkaline side. The data obtained indicate the increase of expression and secretion of anti-inflammatory markers at an alkaline pH shift of reluctate. Analysis of the studied characteristics of the activity profile of macrophages in the proposed in vitro model justifies the need for considering the peculiarities of the functional activity of macrophages under the influence of reluctate different nature. The special importance of studying the cytokine profile and characteristics of the functional activity of macrophages in patients with GERD, given the nature of reluctate

Performance of the Muon Identification at LHCb

The performance of the muon identification in LHCb is extracted from data using muons and hadrons produced in J/\psi->\mu\mu, \Lambda->p\pi and D^{\star}->\pi D0(K\pi) decays. The muon identification procedure is based on the pattern of hits in the muon chambers. A momentum dependent binary requirement is used to reduce the probability of hadrons to be misidentified as muons to the level of 1%, keeping the muon efficiency in the range of 95-98%. As further refinement, a likelihood is built for the muon and non-muon hypotheses. Adding a requirement on this likelihood that provides a total muon efficiency at the level of 93%, the hadron misidentification rates are below 0.6%.Comment: 17 pages, 10 figure

Long-Term Monitoring of Liver Fibrosis and Steatosis in Patients with Chronic Hepatitis C after Achieving a Sustained Virologic Response to Antiviral Therapy

Aim: to analyze the dynamics of fibrosis and steatosis of the liver according to fibroelastometry in patients with chronic hep-atitis C (CHC) after ≥ 6 months from transient elastometry (TE) achieving a sustained virologic response (SVR) to antiviral therapy.Materials and methods. At baseline, a prospective observational study included 628 CHC patients with known stage of liver fibrosis (F) before AVT, some of whom were phased out due to non-compliance with the inclusion criteria. The final analysis included 297 patients who had transient elastometry (TE) data with CAP™ technology on the severity of liver fibrosis (± steatosis) before treatment and after ≥ 6 months after reaching SVR (67 % – interferonfree regimens of therapy). Median follow-up from the moment SVR was confirmed was 3 years [2; 6].Results. At the end of the study, the average age of patients was 49 ± 12 years, of which 53 % were men. In the long-term period after reaching SVR, regression of liver fibrosis was diagnosed in 80 % of cases (including in patients with cirrhosis), and the progression of fibrosis was in 3 % of patient. At the same time, regression of liver steatosis was detected only in 31 % of the patient, worsening of the results was in 23 % (26 % of them had the appearance of steatosis (S) of the liver of 1–3 degrees in persons with no fatty liver before the start of AVT). In the group of patients with liver steatosis, the proportion of men was significantly higher (p = 0.004). Clinically significant stages of fibrosis F3–F4 were significantly more often recorded in patients with hepatic steatosis, both before treatment (46 % S1–S3 and 22 % S0, p < 0.001) and after ≥ 6 months after reaching SVR (19 % S1–S3 and 9 % S0, p = 0.023).Conclusion. In patients with chronic hepatitis C with SVR achieved in the long term, despite a significant regression of liver fibrosis, a high prevalence of hepatic steatosis remains. The data obtained indicate the feasibility of routine diagnosis of both fibrosis and steatosis of the liver in the management of patients with chronic HCV infection before and after successful antiviral therapy

Performance of the LHCb muon system with cosmic rays

The LHCb Muon system performance is presented using cosmic ray events collected in 2009. These events allowed to test and optimize the detector configuration before the LHC start. The space and time alignment and the measurement of chamber efficiency, time resolution and cluster size are described in detail. The results are in agreement with the expected detector performance.Comment: Submitted to JINST and accepte

Performance of the LHCb muon system

The performance of the LHCb Muon system and its stability across the full 2010 data taking with LHC running at ps = 7 TeV energy is studied. The optimization of the detector setting and the time calibration performed with the first collisions delivered by LHC is described. Particle rates, measured for the wide range of luminosities and beam operation conditions experienced during the run, are compared with the values expected from simulation. The space and time alignment of the detectors, chamber efficiency, time resolution and cluster size are evaluated. The detector performance is found to be as expected from specifications or better. Notably the overall efficiency is well above the design requirementsComment: JINST_015P_1112 201

Modern Approaches to the Diagnosis and treatment of <i>Clostridioides difficile (C. difficile)</i>-associated Disease in Adults (literature Review and Expert Council Resolution)

Aim: to review the modern approaches to the diagnosis and treatment of C. difficile-associated disease in adults and present the resolution of the Expert Council held on March 25, 2023 in Moscow.General provisions. C. difficile is the most important nosocomial pathogen which spores are also commonly found in the environment. Microbiota impairment, primarily due to the use of antibacterial drugs, is a key stage in the development of C. difficile-associated disease. A search for an infection should be carried out only in patients with diarrhea, and it is advisable to use at least 2 laboratory methods. The drug of choice for first-line treatment is vancomycin. If drug treatment is ineffective or the patient has recurrent clostridial infection, fecal microbiota transplantation should be considered. The probiotic strain Saccharomyces boulardii CNCM I-745 has a direct inhibitory effect on C. difficile toxin A, promotes normalization of the intestinal microbiota composition, and decreases the inflammatory reaction in colonic mucosa colonized with a toxigenic strain of C. difficile.Conclusions. Addition of the probiotic strain Saccharomyces boulardii CNCM I-745 to antibacterial therapy promotes both primary and secondary prevention of C. difficile-associated disease