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排序方式: 共有1708条查询结果,搜索用时 15 毫秒
71.
Micha Tomaszewski Paulina Makowska Olga Sierawska Rafa Hrynkiewicz Ewa Mroczek Szymon Darocha Anna Hymos Piotr Baszczak Ewelina Grywalska Paulina Nied
wiedzka-Rystwej 《International journal of molecular sciences》2022,23(24)
Pulmonary arterial hypertension (PAH) is an increasingly frequently diagnosed disease, the molecular mechanisms of which have not been thoroughly investigated. The aim of our study was to investigate subpopulations of lymphocytes to better understand their role in the molecular pathomechanisms of various types of PAH and to find a suitable biomarker that could be useful in the differential diagnosis of PAH. Using flow cytometry, we measured the frequencies of lymphocyte subpopulations CD4+CTLA-4+, CD8+ CTLA-4+ and CD19+ CTLA-4+ in patients with different types of PAH, namely pulmonary arterial hypertension associated with congenital heart disease (CHD-PAH), pulmonary arterial hypertension associated with connective tissue disorders (CTD-PAH), chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (iPAH), and in an age- and sex-matched control group in relation to selected clinical parameters. Patients in the iPAH group had the significantly highest percentage of CD4+CTLA-4+ T lymphocytes among all PAH groups, as compared to those in the control group (p < 0.001), patients with CTEPH (p < 0.001), CTD-PAH (p < 0.001) and CHD-PAH (p < 0.01). In iPAH patients, the percentages of CD4+CTLA-4+ T cells correlated strongly positively with the severity of heart failure New York Heart Association (NYHA) Functional Classification (r = 0.7077, p < 0.001). Moreover, the percentage of B CD19+CTLA-4+ cells strongly positively correlated with the concentration of NT-proBNP (r = 0.8498, p < 0.001). We have shown that statistically significantly higher percentages of CD4+CTLA-4+ (p ≤ 0.01) and CD8+ CTLA-4+ (p ≤ 0.001) T cells, measured at the time of iPAH diagnosis, were found in patients who died within 5 years of the diagnosis, which allows us to consider both of the above lymphocyte subpopulations as a negative prognostic/predictive factor in iPAH. CTLA-4 may be a promising biomarker of noninvasive detection of iPAH, but its role in planning the treatment strategy of PAH remains unclear. Further studies on T and B lymphocyte subsets are needed in different types of PAH to ascertain the relationships that exist between them and the disease. 相似文献
72.
A Monte Carlo method was used for a computer simulation of radiation-induced solid state polymerization. The propagation of polymer chains was simulated by means of self-avoiding random walks on a tetrahedral lattice. The initiation and termination of the chains were modelled by pseudorandom processes. The influence of conditions of the in-source process on the post-polymerization kinetics and on the degree of polymerization of the polymers was studied. 相似文献
73.
Zofia Lisiewska Piotr Gębczyński Waldemar Kmiecik 《European Food Research and Technology》2007,226(1-2):25-31
The investigation included kale, New Zealand spinach and spinach. The evaluation covered the raw material; the raw material
after blanching; the raw material after cooking; and frozen products prepared for consumption after 0, 4, 8 and 12 months
of refrigerated storage. Both the traditional method of freezing (blanching before freezing) and the modified method of freezing
(cooked before freezing) were used in the experiment, as well as two storage temperatures, T = −20 °C and T = −30 °C. The content of chlorophylls in fresh kale was four times that in New Zealand spinach and 1.5 times that in spinach.
With the exception of New Zealand spinach, blanching and cooking significantly reduced the content of chlorophylls. In kale
products prepared for consumption, the content of chlorophylls decreased in each successive stage of the investigation. In
products of New Zealand spinach and spinach, the losses were usually not significant. After 12 months of refrigerated storage,
frozen kale products prepared for consumption retained 52–65% of total chlorophylls compared with the content in the raw material;
products of New Zealand spinach and spinach retained 66–71%. In kale and New Zealand spinach, the content of chlorophyll a
decreased more rapidly than that of chlorophyll b, while in spinach the converse was true. The kale products obtained using
the modified method contained more chlorophylls, while in the two spinach species their content was lower. The lower storage
temperature resulted in a higher retention of chlorophylls in vegetables. 相似文献
74.
Łukasz Ciupiński Grzegorz Krzesiński Krzysztof Kurzydłowski Piotr Marek Tomasz Zagrajek Victor Bykov Paweł Czarkowski Wolfgang Daenner Andrzej Dudek Felix Schauer 《Fusion Engineering and Design》2009,84(2-6):613-617
The stellarator Wendelstein 7-X is under construction at the Max-Planck-Institut für Plasmaphysik in Greifswald. Its superconducting coil system is fixed by a massive structure. During machine operation the coils exert high forces and moments against each other and the central support structure (CSS). Therefore, the detailed analysis of the coil to CSS connections, the so-called central support elements (CSE), is a critical item. The major details of the design have been frozen; nevertheless, there is still need for detailed analysis of the CSEs due to assembly issues, and later on for exploring operational limits of the machine. These analyses have to be performed quickly, reliably, and shall provide results in a standardized form to enable timely responses to the assembly team. Special numerical tools – finite element (FE) parametric models of CSEs – have been developed for the purpose of such analyses. In the models, the geometry, material properties, contact conditions, loads as well as results presentation are defined in a parametric way. The use of the developed models for the definition of the final weld parameters, bolt preloads, assessment of acceptable tolerances, and optimal positions of the CSE-wedges before welding is also discussed. 相似文献
75.
76.
Piotr R. Scheller 《国际钢铁研究》2001,72(3):76-80
The surface effects and flow behaviour in melts with a volume of a few cubic millimetres were investigated using 1 mm thick X5CrNi18‐9 (AISI 304) stainless steel strips after partial remelting by a TIG (tungsten inert gas) burner. In the industrially produced material the S mass content was varied between 20 and 100 ppm. The surface excess of sulphur indicates that the surface saturation was not achieved compared to the values in the Fe‐S system. The thickness of the layer with high sulphur enrichment depends on the S activity and varied between approximately 260 and 460 nm and achieves the bulk S content at a distance of approximately 1.2 μm from the surface. This layer is noticeably thinner than the diffusion boundary layer and considerably thinner than the flow boundary layer. The topography of the rapidly solidified liquid pool makes it possible, taking previously estimated temperature coefficients of surface tension into account, to explain the flow behaviour in the melt with regard to the S content and to the temperature gradients. The results obtained indicate that the shearing force caused by surface tension gradients (Marangoni effect) controls the flow conditions in small volume melts. 相似文献
77.
Piotr Macech 《Thin solid films》2009,517(18):5399-5403
Nanoscopic defects present in ultrathin (~ 6 nm) silica films covalently attached to gold substrates through a gold oxide layer exhibit a voltammetric response consistent with a random array of ultramicroelectrodes. These pinholes can be passivated via electrochemical polymerization of phenol to create insulating poly(phenylene) oxide plugs as documented by atomic force microscopy and infrared reflectance-absorbance spectroscopy. Passivation of pinholes is ~ 99.5% complete after 550 voltammetric cycles of oxidative electropolymerization. 相似文献
78.
The multistep consecutive ECE-ECE reduction process A(e)-->B(k(f2))-->C(e)-->D(e)-->E(k(f2))-->F(e)-->G has been compared with reduction in multicomponent system A(e)-->B, C(e)-->D, D(e)-->E, F(e)-->G. A simple method of transformation has been devised to disclose the subtle structure of the complex cyclic voltammetry (CV) responses and illustrated by the ECE-ECE process modeled earlier. The method can be applied to any multi-electron CV experimental curve for which a numerical modeling has been done. Electroreduction processes similar to those considered here are often met in practice. An attempt of unification of consecutive electroreduction and electroreduction of multicomponent system has been made. Interrelation between research and analytical voltammetry aspects of the problem is also discussed. 相似文献
79.
The paper deals with the problem of finding optimal testing policy to minimize the average cost of determining the state of a s-coherent system. Computational complexity of this problem is analysed and strong evidence presented that an exact, polynomial-time, algorithm is very unlikely to exist. Instead, three approximate algorithms having polynomial running times are suggested and evaluated. Two of them guarantee reasonably good solutions and might be practical. 相似文献
80.
Kiełczyński P 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2004,51(11):1367-1372
In this paper, a formula relating the shift in the resonant frequency of a shear piezoceramic cylindrical resonator to the viscosity of a Newtonian liquid that loads the resonator surface was established. This formula is analogous to the classical Kanazawa-Gordon formula that describes the change in the resonant frequency of a shear planar resonator loaded with a Newtonian liquid. To this end, the author applied the perturbation method to analyze the behavior of the piezoceramic cylindrical resonators vibrating in a shear mode and loaded with a viscous liquid. The shift in resonant frequency obtained using the perturbation method (mechanical model) was compared to an exact value of the shift in resonant frequency obtained from the complete electromechanical model (admittance diagrams) that describes shear vibrations of a piezoceramic cylindrical resonator loaded with a viscous liquid. Good conformity between the two types of results obtained can prove the correctness of the analytical formulas established in this paper. The results of this work can be applied for the design and construction of viscosity sensors. 相似文献