52 research outputs found

    A cryogenic axial-centrifugal compressor for superfluid helium refrigeration

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    CERN's new project, the Large Hadron Collider (LHC), will use superfluid helium as coolant for its high-field superconducting magnets and therefore require large capacity refrigeration at 1.8 K. This may only be achieved by subatmospheric compression of gaseous helium at cryogenic temperature. To stimulate development of this technology, CERN has procured from industry prototype Cold Compressor Units (CCU). This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating under low-pressure helium at ambient temperature. The machine has been commissioned and is now in operation. After describing basic constructional features of the compressor, we report on measured performance

    Study of suitability of Fricke-gel-layer dosimeters for in-air measurements to characterize epithermal/thermal neutron beams for NCT

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    The reliability of Fricke gel dosimeters in form of layers for measurements aimed at the characterization of epithermal neutron beams has been studied. By means of dosimeters of different isotopic composition (standard, containing 10B or prepared with heavy water) placed against the collimator exit, the spatial distribution of gamma and fast neutron doses and of thermal neutron fluence are attained. In order to investigate the accuracy of the results obtained with in-air measurements, suitable MC simulations have been developed and experimental measurements have been performed utilizing Fricke gel dosimeters, thermoluminescence detectors and activation foils. The studies were related to the epithermal beam designed for BNCT irradiations at the research reactor LVR-15 (Řež). The results of calculation and measurements have revealed good consistency of gamma dose and fast neutron 2D distributions obtained with gel dosimeters in form of layers. In contrast, noticeable modification of thermal neutron fluence is caused by the neutron moderation produced by the dosimeter material. Fricke gel dosimeters in thin cylinders, with diameter not greater than 3 mm, have proved to give good results for thermal neutron profiling. For greater accuracy of all results, a better knowledge of the dependence of gel dosimeter sensitivity on radiation LET is needed

    BNCT dosimetry: peculiarities and methods

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    Dosimetry in tissue exposed to the epithermal neutron beams utilized for BNCT is complex, due to the multiplicity of the possible neutron reactions and consequently of the secondary radiation that contains photons, charged particles and recoil nuclei. Owing to the different radiobiological effectiveness of the various components of the absorbed dose, it is necessary to attain the evaluation of each of them. In addition, the spatial distributions of these dose components changes considerably with size and shape of the irradiated volume. Therefore, BNCT dosimetry requires suitably developed calculations and experimental methods. In this work, Monte Carlo simulations in phantoms of different sizes and shapes have been developed. Experimental methods for separating the dose components, mainly based on gel dosimeters and thermoluminescence detectors, have been applied. Moreover, the change in the absorbed dose resulting from the addition of 157Gd was investigated. Both measurements and calculations have been done with the BNCT epithermal beam of the LVR-15 reactor

    Interleukins 4 and 6 as factors of modulation of subpopulation composition of blood monocytes in patients with ischemic cardiomyopathy

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    Aim. To evaluate the ratio of the fractions of classical, intermediate, non-classical and transitional monocytes in correlation with the concentration of interleukins 4 and 6 in the blood of patients with ischemic cardiomyopathy. Methods. 18 patients with ischemic cardiomyopathy (17 men and 1 woman) aged 47-66 years with circulatory insufficiency of functional class II-III according to the classification of heart failure of the New York Heart Association, were examined. The control group included 14 healthy donors matched by gender and age to patients with ischemic cardiomyopathy without any diseases of cardiovascular system and other systems in an exacerbation stage. In blood of the patients with ischemic cardiomyopathy, the relative content of classical (CD14++CD16-), intermediate (CD14++CD16+), non-classical (CD14+CD16+) and transitional (CD14+CD16-) monocytes was assessed by flow cytometry and the concentration of interleukins 4 and 6 by enzyme-linked immunosorbent assay (ELISA). Results. It was shown that the number of non-classical monocytes in the blood of patients with ischemic cardiomyopathy was 2 times lower than normal (5.05 % [4.08; 6.58] and 10.07 % [9.34; 13.84], respectively, p < 0.01), as well as the concentration of interleukin-4 (0.02 pg/ml [0; 0.04] and 0.15 pg/ml [0.05; 0.65], respectively, p < 0.05). The number of classical monocytes in the blood of patients had a tendency to decrease, and the proportion of intermediate monocytes and the concentration of interleukin-6, on the contrary, were slightly higher than in healthy individuals, and were interdependent (r = 0.61; p < 0.05). The relative content of transitional monocytes in the blood was comparable with that of healthy donors. Conclusions. The subpopulation composition of blood monocytes in patients with ischemic cardiomyopathy is characterized by a deficiency of the fraction of non-classical monocytes with protective properties against endothelium, and interleukin-4 in the blood with a certain increase in the content of interleukin-6 and the number of intermediate cells with ability to cooperate with T-lymphocytes, which predisposes to diffuse atheromatosis of small coronary arteries and diffuse hypoxic myocardial damage in ischemic cardiomyopathy

    Interaction of Nitrogen-Vacancy Centers in Diamond with a Dense Ensemble of Carbon-13

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    The nitrogen-vacancy center in diamond attracts a lot of attention in sensing applications, mainly for temperature, magnetic field, and rotation measurements. Nuclear spins of carbon-13 surrounding the nitrogen-vacancy center can be used as a memory or sensing element. In the current work, a diamond plate with a relatively large concentration of carbon-13 was synthesized and examined. The spectrum of optically detected magnetic resonance was recorded and analyzed in a magnetic field range of 5-200 G. A strain-independent measurement technique of carbon-13 isotope concentration based on the analysis of magnetic resonance spectra was developed. Additionally, narrow features in the spectrum were detected and understood

    The TOTEM Experiment at the CERN Large Hadron Collider

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    The TOTEM Experiment will measure the total pp cross-section with the luminosity independent method and study elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, will be installed on each side in the pseudorapidity region 3,1 <h< 6,5, and Roman Pot stations will be placed at distances of 147m and 220m from IP5. Being an independent experiment but technically integrated into CMS, TOTEM will first operate in standalone mode to pursue its own physics programme and at a later stage together with CMS for a common physics programme. This article gives a description of the TOTEM apparatus and its performance

    Макрофаги при бактериальных болезнях легких: фенотип и функции (обзор)

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    This literature review is devoted to the analysis of the role of macrophages in the immunopathogenesis of infectious lung diseases of bacterial etiology. The article summarizes information about the origin of macrophages, their phenotypic and functional heterogeneity. The mechanisms of impaired protective function of innate immunity are associated with the polarization of the program of maturation and activation of macrophages in the direction to tolerogenic or immunoregulatory cells with phenotype of M2. Alveolar macrophages perform a variety of functions (from pro-inflammatory to regenerative) in the development of inflammation in the respiratory organs. Their inherent plasticity suggests that the same macrophages can change their phenotype and function depending on the microenvironment in the inflammatory focus at different stages of the disease. Understanding the mechanisms that regulate macrophage plasticity will be an important step towards realizing the potential of personalized immunomodulatory therapy.Обзор литературы посвящен анализу роли макрофагов в иммунопатогенезе инфекционных заболеваний легких бактериальной этиологии. В статье обобщены сведения о происхождении макрофагов, их фенотипической и функциональной гетерогенности. Механизмы нарушений защитной функции врожденного иммунитета связаны с поляризацией программы созревания и активации макрофагов в направлении толерогенных или иммунорегуляторных клеток с фенотипом М2. Альвеолярные макрофаги выполняют разнообразные функции (от провоспалительной до регенераторной) при развитии воспаления в органах дыхания. Присущая им пластичность свидетельствует, что одни и те же макрофаги могут изменять свой фенотип и функции в зависимости от микроокружения в очаге воспаления на разных стадиях заболевания. Понимание механизмов, которые регулируют пластичность макрофагов, станет важным шагом на пути реализации потенциала персонифицированной иммуномодулирующей терапии

    Субпопуляционный состав моноцитов крови и костного мозга у больных с хронической сердечной недостаточностью

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    The aim of the investigation was to evaluate the ratio of classical (CD14++CD16-), intermediate (CD14++CD16+), nonclassical (CD14+CD16+) and transient (CD14+CD16–) monocytes in the blood and bone marrow in patients with chronic heart failure (CHF) against ischemic cardiomyopathy (ICMP).Materials and methods. 17 patients with ICMP and 14 practically healthy donors were observed. The material of the study was venous blood (in patients and healthy donors) and red bone marrow (in patients). In the materials the relative content of different monocytes subpopulations was determined by flow cytometry. The obtained results were analyzed by statistical methods.Results. It is shown that in the blood of patients the proportion of monocytes with the phenotype CD14++CD16- is 57.77 [of 46.35; 79.76]%, CD14++CD16+ – 25.06 [4.96; 42.31]%, CD14+CD16+ 5.05 [4.08; 6.58]% and CD14+CD16- – 6.03 [3.58; 10.89]%; in the bone marrow – 43.44 [40.54; 44.68]%, 0.16 [0; 1.07]%, 0,54 [0.35; 1.07]% and 54,32 [52.83; 56.08]%, respectively, which is different from the content of the data cells subpopulations in the blood (p &lt; 0.05). At the same time, the content of non-classical monocytes in the patients’ blood is 2 times lower than in healthy donors, and the number of other cells varies within the norm.Conclusion. The differentiation of monocytes into 4 subpopulations in patients with CHF occurs directly in the bloodstream, since mainly the classical and transitional monocyte fractions with the prevalence of the latter are present in the bone marrow. Deficiency of non-classical monocytes of blood in CHF is probably associated with a disruption of their extramedullary differentiation.Цель работы – оценить соотношение классических (CD14++CD16-), промежуточных (CD14++CD16+), неклассических (CD14+CD16+) и переходных (CD14+CD16-) моноцитов в крови и костном мозге у больных с хронической сердечной недостаточностью (ХСН) на фоне ишемической кардиомиопатии (ИКМП).Материалы и методы. Обследованы 17 больных ИКМП и 14 практически здоровых доноров. Материалом для исследования служили венозная кровь (у больных и здоровых доноров) и красный костный мозг (у больных). В материале определяли относительное содержание различных субпопуляций моноцитов методом проточной цитометрии. Полученные результаты анализировали статистическими методами.Результаты. Показано, что в крови у больных доля моноцитов с фенотипом CD14++CD16- составляет 57,77 [46,35; 79,76]%; CD14++CD16+ – 25,06 [4,96; 42,31]%; CD14+CD16+ – 5,05 [4,08; 6,58]% и CD14+CD16- – 6,03 [3,58; 10,89]%; в костном мозге – 43,44 [40,54; 44,68]%; 0,16 [0; 1,07]%; 0,54 [0,35; 1,07]% и 54,32 [52,83; 56,08]% соответственно, что отличается от содержания клеток данных субпопуляций в крови (р &lt; 0,05). При этом содержание неклассических моноцитов в их крови в два раза ниже, чем у здоровых доноров, а численность остальных клеток варьирует в пределах нормы.Заключение. У больных ХСН распределение моноцитов на четыре субпопуляции происходит непосредственно в кровотоке, так как в костном мозге обнаруживаются в основном классическая и переходная фракции моноцитов с преобладанием клеток CD14+CD16+. Дефицит неклассических моноцитов в крови при ХСН, вероятно, связан с нарушением их экстрамедуллярной дифференцировки

    Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

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    Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.
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