138 research outputs found

    CHANGES IN THE LEVELS OF ANGIOTENSIN II, ALDOSTERONE, AND FIBROBLAST GROWTH FACTOR IN PATIENTS WITH RHEUMATOID ARTHRITIS IN RELATION TO CLINICAL FEATURES

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    Angiotensin II, aldosterone, and fibroblast growth factor (FGF) stimulate neoangiogenesis, fibroblast proliferation, and elaboration of proinflammatory cytokines, which in turn contributes to increased pannus mass and the development of joint tissue destruction in rheumatoid arthritis (RA).Objective: to establish the specific features of changes in the blood levels of angiotensin II, aldosterone, and FGF in patients with RA in relation to the duration and severity of the disease.Subjects and methods. Examinations were made in 194 patients diagnosed with RA without comorbidity; the patients’ mean age was 47.7±10.2 years; the disease duration was 3.82±3.43 years. DAS28 scores for RA were calculated based on C-reactive protein levels. An enzyme immunoassay was used to determine the serum levels of anti-cyclic citrullinated peptide antibodies (ACCPA), angiotensin II, aldosterone, and FGF.Results and discussion. All the examinees were ascertained to have increases in the concentration of angiotensin II and aldosterone in blood by twice and in that of FGF by 2.5 times compared to the controls (p < 0.05). In patients with a RA duration of < 2 years, the blood level of angiotensin II was 25% higher than in those with a RA duration of > 5 years and the concentrations of aldosterone and FGF in patients with long-term RA were twice as high as in those with early RA. In patients with high RA activity, the blood level of angiotensin II was 1.5-fold higher than in those with low and moderate disease activity (p < 0.05). In patients with a high blood ACCPA level, the concentrations of angiotensin II, aldosterone, and FGF were 20, 30, and 25%, respectively, higher than in those with low ACCPA levels. The correlation of DAS28 with blood angiotensin II levels increased with enhanced RA activity. The high aldosterone and FGF values in RA patients are associated with the progression of joint radiographic changes

    Axisymmetric deformation of compressible, nearly incompressible, and incompressible thin layers between two rigid surfaces

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    Accurate asymptotic solutions are presented for axisymmetric deformation of thin layers constrained by either two rigid plates or two rigid spheres. Those solutions are developed using Saint-Venant's principle and the layer thinness as the only assumptions. The solutions are valid in the entire range of Poisson's ratios, and allow one to distinguish among compressible, nearly incompressible, and incompressible layers. That classification involves both material and geometric parameters

    Mechanistic Insights into the Desorption of Methanol and Dimethyl Ether Over ZSM-5 Catalysts

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    Acknowledgements Financial support from the Petroleum Technology Development Fund of Nigeria (PTDF/ED/PHD/OO/766/15) and from the European Commission in the scope of the 7th Framework program BIOGO project (Grant Number: 604296) https://www.biogo. eu/ is acknowledged.Peer reviewedPublisher PD

    Ингибитор ангиотензинпревращающего фермента в комплексном лечении ревматоидного а ртрита

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    Angiotensin-converting enzyme (ACE) inhibitors have anti-inflammatory and antiproliferative properties and can affect the processes of angiogenesis, by reducing the effects of angiotensin II (ATII). The use of ACE inhibitors in the combination therapy of rheumatoid arthritis (RA) can be also effective for monitoring disease activity and for reducing a cardiovascular risk.Objective: to evaluate the efficacy of an ACE inhibitor in the combination therapy of RA.Patients and methods. Eighty-four patients with RA and endothelial dysfunction were examined; the mean age was 40.12±10.2 years; the mean disease duration was 4.22±3.43 years. All the patients had a blood level of ATII of >9 pg/ml. Enzyme immunoassay was used to measure the levels of tumor necrosis factor-α (TNF-α) (Vector-Best, Russia), intercellular adhesion molecules 1 (ICAM-1) (Diaclone, France), vascular endothelial growth factor (VEGF) and ATII (Diagnostic, Canada). Wrist ultrasonography using the Doppler ultrasound apparatus ESAOTE MyLAB40 was carried out to assess synovial vascularization. The patients were divided into two groups. Group 1 included 43 patients who were assigned to receive standard therapy for RA according to the rheumatic disease treatment protocols; Group 2 comprised 41 patients who received the standard therapy plus ACE inhibitors 2.5–5 mg/day.Results. The use of ACE inhibitors in the 12-month combination therapy of RA patients led to an improvement in the endothelial regulation of vascular tone, to a decrease in the blood concentration of ICAM-1, to a reduction in the intensity of synovial angiogenesis and in the blood level of VEGF by 39%, and a more significant drop in the levels of CRP and TNF-? and in DAS28 by 1.2 scores as compared to those in the standard therapy.Ингибиторы ангиотензинпревращающего фермента (иАПФ) обладают противовоспалительными, антипролиферативными свойствами и могут влиять на процессы ангиогенеза через снижение эффектов ангиотензина II (АТІІ). Применение иАПФ в комплексной терапии ревматоидного артрита (РА) может быть эффективно и для контроля активности заболевания, и для снижения риска сердечно-сосудистых заболеваний.Цель исследования – оценка эффективности иАПФ в комплексной терапии РА.Пациенты и методы. Обследовано 84 больных РА с наличием эндотелиальной дисфункции, средний возраст – 40,12±10,2 года, средняя длительность РА – 4,22±3,43 года. У всех пациентов содержание АТІІ в крови составляло 9 пг/мл. С помощью иммуноферментного анализа определяли уровень фактора некроза опухоли α (ФНОα; «Вектор-Бест», Россия), молекул межклеточной адгезии (ICAM-1; Diaclone, Франция), сосудистого эндотелиального фактора роста (VEGF) и АТII (Diagnostic, Канада). Для оценки васкуляризации синовиальной оболочки (СО) выполняли УЗИ суставов кисти с допплером на аппарате ESAOTE MyLAB 40. Пациенты были разделены на две группы. В 1-ю группу вошли 43 пациента, которым была назначена стандартная терапия РА, согласно протоколам лечения ревматических заболеваний, во 2-ю группу – 41 пациент, получавший стандартную терапию с добавлением иАПФ 2,5–5 мг/сут.Результаты. Применение иАПФ в комплексной терапии больных РА в течение 12 мес приводило к улучшению показателей эндотелиальной регуляции сосудистого тонуса, снижению концентрации ICAM-1 в крови, уменьшению интенсивности ангиогенеза в СО и уровня VEGF в крови на 39%, более существенному снижению уровня СРБ, ФНОα и индекса активности DAS28 на 1,2 балла по сравнению с таковыми на фоне стандартной терапии

    Mathematical model of diesel engine characteristics for determining the performance of traction dynamics of wheel-type tractor

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    Wheel-type tractors carry out a range of processing operations, with the exception of early spring work, when caterpillar tractors are used to reduce the compaction effect on the soil. Therefore, to plan the costs and reserves associated with fuel consumption, it is necessary to have an estimate of the fuel economy of the tractor in basic agricultural operations. An objective assessment of fuel consumption requires a mathematical model that describes the fuel characteristics of the engine, taking into account the speed and load torque in a wide range of variation. Verification of the model is possible only with experimental data. Since the efficiency and fuel economy of a tractor depends not only on engine performance, but also on the perfection of the transmission, the running system and the rational choice of speed, it is necessary to take into account the time-varying nature of the tractor’s traction load. The complex of agricultural operations can be divided into characteristic cycles of load change over time. This principle is the basis of PowerMix test cycles, which are conducted on a concrete track to ensure repeatability of the experiment. The use of the variable load on the tractor in the PowerMix tests is positive, but in actual field tests the results may differ due to the instability of the soil properties. On the other hand, PowerMix field cycles can be taken as standard test loads in the simulation of tractor traction tests on the ground

    Non-Equilibrium Reaction Rates in the Macroscopic Chemistry Method for DSMC Calculations

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    The Direct Simulation Monte Carlo (DSMC) method is used to simulate the flow of rarefied gases. In the Macroscopic Chemistry Method (MCM) for DSMC, chemical reaction rates calculated from local macroscopic flow properties are enforced in each cell. Unlike the standard total collision energy (TCE) chemistry model for DSMC, the new method is not restricted to an Arrhenius form of the reaction rate coefficient, nor is it restricted to a collision cross-section which yields a simple power-law viscosity. For reaction rates of interest in aerospace applications, chemically reacting collisions are generally infrequent events and, as such, local equilibrium conditions are established before a significant number of chemical reactions occur. Hence, the reaction rates which have been used in MCM have been calculated from the reaction rate data which are expected to be correct only for conditions of thermal equilibrium. Here we consider artificially high reaction rates so that the fraction of reacting collisions is not small and propose a simple method of estimating the rates of chemical reactions which can be used in the Macroscopic Chemistry Method in both equilibrium and non-equilibrium conditions. Two tests are presented: (1) The dissociation rates under conditions of thermal non-equilibrium are determined from a zero-dimensional Monte-Carlo sampling procedure which simulates ‘intra-modal’ non-equilibrium; that is, equilibrium distributions in each of the translational, rotational and vibrational modes but with different temperatures for each mode; (2) The 2-D hypersonic flow of molecular oxygen over a vertical plate at Mach 30 is calculated. In both cases the new method produces results in close agreement with those given by the standard TCE model in the same highly nonequilibrium conditions. We conclude that the general method of estimating the non-equilibrium reaction rate is a simple means by which information contained within non-equilibrium distribution functions predicted by the DSMC method can be included in the Macroscopic Chemistry Method

    Metal oxide–zeolite composites in transformation of methanol to hydrocarbons : do iron oxide and nickel oxide matter?

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    The methanol-to-hydrocarbon (MTH) reaction has received considerable attention as utilizing renewable sources of both value-added chemicals and fuels becomes a number one priority for society. Here, for the first time we report the development of hierarchical zeolites (ZSM-5) containing both iron oxide and nickel oxide nanoparticles. By modifying the iron oxide (magnetite, Fe3O4) amounts, we are able to control the catalyst activity and the product distribution in the MTH process. At the medium Fe3O4 loading, the major fraction is composed of C9–C11 hydrocarbons (gasoline fraction). At the higher Fe3O4 loading, C1–C4 hydrocarbons prevail in the reaction mixture, while at the lowest magnetite loading the major component is the C5–C8 hydrocarbons. Addition of Ni species to Fe3O4–ZSM-5 leads to the formation of mixed Ni oxides (NiO/Ni2O3) positioned either on top of or next to Fe3O4 nanoparticles. This modification allowed us to significantly improve the catalyst stability due to diminishing coke formation and disordering of the coke formed. The incorporation of Ni oxide species also leads to a higher catalyst activity (up to 9.3 g(methanol)/(g(ZSM-5) × h)) and an improved selectivity (11.3% of the C5–C8 hydrocarbons and 23.6% of the C9–C11 hydrocarbons), making these zeolites highly promising for industrial applications

    Catalytic pyrolysis of plastics over maghemite-impregnated mesocellular foam using induction heating

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    Pyrolysis is a key technology that converts unrecyclable end-of-life plastics into value-added products. Nevertheless, the high energy consumption during plastic pyrolysis limits the economic feasibility of a scaledup process. Development of an energy-efficient plastic pyrolysis process is necessary to realise its full potential in the circular economy. Catalysts derived from mesocellular foam possess high acidity and mesoporosity, and exhibit high catalytic activity in chemical reactions. Application of such catalyst in plastic pyrolysis has never been reported. This work presents the catalytic pyrolysis of low- and high-density polyethylene and polypropylene over maghemite-impregnated mesocellular foam (Fe@AlMCF). Fe@AlMCF has a BET surface area of 629.8 m2/g and a strong Brønsted acidity (677 µmol/gcat). The catalyst contains pentagonal and hexagonal packed mesostructure. Induction heating resulted in a rapid increase in reactor temperature (at 65°C /min) and complete plastics conversion within 10 min. Catalytic pyrolysis produced gas products rich in C3 compounds. The liquid products were rich in alkenes (69.7-71.3 %) and alkanes, followed by aromatics (10.4- 12.8 %). These observations indicate that the highly acidic Fe@AlMCF catalysed hydrocarbon aromatization within a short reaction time. Thermal analysis of the spent catalysts revealed considerably high coke yields (5.78 - 6.03 %), as the higher acidity of the original catalyst promoted coke precursor formation. Based on the research findings, induction heating can rapidly and effectively convert plastics into hydrocarbon feedstocks, and Fe@AlMCF is a valuable catalyst for plastic pyrolysis
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