463 research outputs found

    Modeling of Pyrolysis in a Stage Scheme of Low‐Grade Solid Fuel Gasification

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    This paper is concerned with the development of a model of wood pyrolysis in a screw reactor as the first stage of the multistage gasification process. In terms of design, the pilot pyrolyzer represents a recuperative heat exchanger where the heat carrier is represented by a mixture of exhaust and recirculation gases. To prevent clinkering of particles and thermal inhomogeneities, screw‐type transportation is used to transport fuel. In order to describe kinetics of pyrolysis and transport of volatiles within the wood particles and their transition to the gas phase, we carried out the studies using a complex of synchronous thermal analysis. The original techniques for the interpretation of measurements were developed for this complex, including the techniques for technical analysis of fuels and identification of detailed kinetics and mechanism of pyrolysis. A detailed numerical modeling of pyrolyzer was performed using the Comsol Multiphysics software, which makes it possible to optimize the design and operating parameters of the pyrolysis process in a screw reactor

    Structural insights into molecular function of the metastasis-associated phosphatase PRL-3.

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    Phosphatases and kinases are the cellular signal transduction enzymes that control protein phosphorylation. PRL phosphatases constitute a novel class of small (20 kDa), prenylated phosphatases with oncogenic activity. In particular, PRL-3 is consistently overexpressed in liver metastasis in colorectal cancer cells and represents a new therapeutic target. Here, we present the solution structure of PRL-3, the first structure of a PRL phosphatase. The structure places PRL phosphatases in the class of dual specificity phosphatases with closest structural homology to the VHR phosphatase. The structure, coupled with kinetic studies of site-directed mutants, identifies functionally important residues and reveals unique features, differentiating PRLs from other phosphatases. These differences include an unusually hydrophobic active site without the catalytically important serine/threonine found in most other phosphatases. The position of the general acid loop indicates the presence of conformational change upon catalysis. The studies also identify a potential regulatory role of Cys(49) that forms an intramolecular disulfide bond with the catalytic Cys(104) even under mildly reducing conditions. Molecular modeling of the highly homologous PRL-1 and PRL-2 phosphatases revealed unique surface elements that are potentially important for specificity

    Uniform resolvent convergence for strip with fast oscillating boundary

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    In a planar infinite strip with a fast oscillating boundary we consider an elliptic operator assuming that both the period and the amplitude of the oscillations are small. On the oscillating boundary we impose Dirichlet, Neumann or Robin boundary condition. In all cases we describe the homogenized operator, establish the uniform resolvent convergence of the perturbed resolvent to the homogenized one, and prove the estimates for the rate of convergence. These results are obtained as the order of the amplitude of the oscillations is less, equal or greater than that of the period. It is shown that under the homogenization the type of the boundary condition can change

    Disentangling methane and carbon dioxide sources and transport across the Russian Arctic from aircraft measurements

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    A more accurate characterization of the sources and sinks of methane (CH4) and carbon dioxide (CO2) in the vulnerable Arctic environment is required to better predict climate change. A large-scale aircraft campaign took place in September 2020 focusing on the Siberian Arctic coast. CH4 and CO2 were measured in situ during the campaign and form the core of this study. Measured ozone (O3) and carbon monoxide (CO) are used here as tracers. Median CH4 mixing ratios are fairly higher than the monthly mean hemispheric reference (Mauna Loa, Hawaii, US) with 1890&ndash;1969 ppb vs 1887 ppb respectively, while CO2 mixing ratios from all flights are lower (408.09&ndash;411.50 ppm vs 411.52 ppm). We also report on three case studies. Our analysis suggests that during the campaign the European part of Russia&rsquo;s Arctic and Western Siberia were subject to long-range transport of polluted air masses, while the East was mainly under the influence of local emissions of greenhouse gases. The relative contributions of the main anthropogenic and natural sources of CH4 are simulated using the Lagrangian model FLEXPART in order to identify dominant sources in the boundary layer and in the free troposphere. In western terrestrial flights, air masses composition is influenced by emissions from wetlands and anthropogenic activities (waste management, fossil fuel industry and to a lesser extent the agricultural sector), while in the East, emissions are dominated by freshwaters, wetlands, and the oceans, with a likely contribution from anthropogenic sources related to fossil fuels. Our results highlight the importance of the contributions from freshwater and oceans emissions. Considering the large uncertainties associated to them, our study suggests that the emissions from these aquatic sources should receive more attention in Siberia.</p

    The use of argon plasma coagulation in mammoplasty as a prevention of postoperative complications

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    The frequency of reoperations associated with complications after mammoplasty reaches 15 % during the first year. There are many ways and means for processing the soft tissues of the breast during mammoplasty, helping to reduce the risk of postoperative complications. The purpose of this work was to develop an algorithm for the application of the argon plasma technique for tissue treatment in mammoplasty. Material and methods. The study included 30 females aged 23 to 46 who underwent mammoplasty. The patients were divided into 2 groups of 15 people. In group 1, standard methods of processing soft tissues were used, and in group 2, the argon plasma technique was used in conjunction with the use of Aristo glue. Patients were observed in the early, late and distant postoperative period. Results. In the course of the study, in addition to the excellent coagulation and bactericidal action of argon plasma, the effect of “pulling up” the soft tissues of the mammary gland was found, which, in case of ptosis of I and II degrees, made it possible to use a smaller implant to achieve an optimal aesthetic result. Also, when using the argon plasma technology, no inflammatory processes were observed, the amount of exudative fluid in the drains decreased, the pain syndrome was significantly less pronounced in comparison with patients who underwent the standard method of tissue processing. Conclusions. This study confirms the fact that the use of argon plasma coagulation in the processing of breast tissue has a significant number of advantages compared to standard methods

    Precise measurement of the W-boson mass with the CDF II detector

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    We have measured the W-boson mass MW using data corresponding to 2.2/fb of integrated luminosity collected in proton-antiproton collisions at 1.96 TeV with the CDF II detector at the Fermilab Tevatron collider. Samples consisting of 470126 W->enu candidates and 624708 W->munu candidates yield the measurement MW = 80387 +- 12 (stat) +- 15 (syst) = 80387 +- 19 MeV. This is the most precise measurement of the W-boson mass to date and significantly exceeds the precision of all previous measurements combined

    The efficacy of the combination of eribulin and trastuzumab in advanced HER2-positive breast cancer: the results of Russian observational study

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    The article presents the experience of 19 Russian medical institutions on the use of eribulin in combination with trastuzumab in various treatment lines of metastatic HER2+ breast cancer in routine clinical practice. Aim. The main objective of this retrospective observational study was to evaluate the efficacy and tolerability of eribulin and trastuzumab combo in HER2+ breast cancer patients pretreated with anthracyclines and taxanes. The analysis included 60 patients who received at least 2 cycles of eribulin in combination with trastuzumab. 2 patients (3.3%) received treatment as the 1st line, as the 2nd 14 (23.3%), as the 3rd 16 (26.7%), and as the 4th and more 28 (46.7%). Materials and methods. Complete response was achieved in 2 (3.3%) patients, partial response in 9 (15%), stable disease in 33 (55%), stabilization for more than 6 months in 11 (18.3%), disease progression was detected in 16 (26.7%) patients. The objective response rate was 18.3% in the whole group, the clinical benefit rate 36.7%. Results. The objective response rate in the group of the luminal subtype (ER/PR+HER2+) was 26.9%, in HER2-overexpressed subtype (ER-PR-HER2+) 8.8% and 64.7%, respectively, disease progression was recorded 2.3 times more often 35.3% versus 15.5% in the luminal subtype group. The median progression-free survival in patients with HER2+ breast cancer was 4.95 months (95% confidence interval CI 3.048.29 months), in luminal subtype 6.38 months (95% CI 3.338.54 months), in non-luminal 4.44 months (95% CI 2.47.96 months); p=0.306. The treatment was well tolerated, the spectrum of adverse events corresponded to the eribulin toxicity profile. Conclusions. The uniqueness of this study lies in the fact that on a large clinical material from the standpoint of real clinical practice, a very promising treatment regimen that is not used routinely in a number of countries has been studied, its effectiveness and satisfactory tolerance have been confirmed

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
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