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排序方式: 共有842条查询结果,搜索用时 734 毫秒
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Machine Learning - The coronavirus disease 2019 (COVID-19) global pandemic poses the threat of overwhelming healthcare systems with unprecedented demands for intensive care resources. Managing... 相似文献
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Marta Izabela Jonas Alina Kurylowicz Zbigniew Bartoszewicz Wojciech Lisik Maurycy Jonas Zbigniew Wierzbicki Andrzej Chmura Piotr Pruszczyk Monika Puzianowska-Kuznicka 《International journal of molecular sciences》2015,16(10):25817-25830
Excess adiposity is associated with chronic inflammation, which takes part in the development of obesity-related complications. The aim of this study was to establish whether subcutaneous (SAT) or visceral (VAT) adipose tissue plays a major role in synthesis of pro-inflammatory cytokines. Concentrations of interleukins (IL): 1β, 6, 8 and 15 were measured at the protein level by an ELISA-based method and on the mRNA level by real-time PCR in VAT and SAT samples obtained from 49 obese (BMI > 40 kg/m2) and 16 normal-weight (BMI 20–24.9 kg/m2) controls. IL-6 and IL-15 protein concentrations were higher in SAT than in VAT for both obese (p = 0.003 and p < 0.0001, respectively) and control individuals (p = 0.004 and p = 0.001, respectively), while for IL-1β this was observed only in obese subjects (p = 0.047). What characterized obese individuals was the higher expression of IL-6 and IL-15 at the protein level in VAT compared to normal-weight controls (p = 0.047 and p = 0.016, respectively). Additionally, obese individuals with metabolic syndrome had higher IL-1β levels in VAT than did obese individuals without this syndrome (p = 0.003). In conclusion, concentrations of some pro-inflammatory cytokines were higher in SAT than in VAT, but it was the increased pro-inflammatory activity of VAT that was associated with obesity and metabolic syndrome. 相似文献
105.
Viorel Badescu 《国际能源研究杂志》2020,44(7):5360-5384
The design and steady-state operation of a packed bed reactor with tubular geometry is optimized. Direct optimal control methods are used. Two objective functions are considered: (i) minimization of the ammonia mass fraction at reactor outlet and (ii) minimization of the heat flux necessary to reach a predefined value of the ammonia mass fraction at reactor outlet. The optimization process is performed by using different controls, that is, the space distributions of (1) tube wall temperature Tw , (2) circular tube diameter Dtube , and (3) diameter dp of the catalyst spherical particles. Results for the first objective function are as follows. The optimal distribution of Tw along the reactor consists of a constant temperature or a U-shaped space temperature distribution, respectively, depending on the allowed range of variation of Tw . The optimal space distribution of Dtube (or, in other words, the shape of the reactor tube) depends of Tw . For smaller values of Tw the tube is narrower at inlet and larger at outlet while the reverse situation happens for larger values of Tw . For lower Tw values, particles with smaller diameter dp are placed at reactor inlet while when higher values of Tw are considered, particles with larger dp are placed at reactor inlet. When both Dtube and dp are used as controls, the optimization results are generally different from the results obtained from one-control optimization. Results for the second objective function are as follows. The optimal space distribution of Tw starts with high values at reactor inlet. Next, the temperature decreases abruptly towards a minimum (which is lower for longer tubes). Finally, the temperature increases smoothly towards a maximum near the reactor outlet. The required heat flux slightly decreases by increasing the tube length. The optimal Dtube ranges between its maximum allowed value (at reactor inlet) and its minimum allowed value (at reactor outlet). The best performance is obtained for catalyst particles of the smallest allowed diameter. 相似文献
106.
Alexander Filippov Alina I Amirova Tatiana Kirila Elena V Belyaeva Natalia A Sheremetyeva Aziz M Muzafarov 《Polymer International》2015,64(6):780-786
A carbosilane pseudo‐dendrimer with irregular structure and degree of branching DB = 1 was synthesized and fractionated. The molar masses of the obtained fractions ranged from 5000 to 490 000 g mol?1. The hydrodynamic and conformational properties were studied by the methods of light scattering, sedimentation‐diffusion analysis and viscometry in dilute hexane and toluene solutions. The Mark ? Kuhn ? Houwink dependences were obtained. The results for the pseudo‐dendrimer are compared with the data for the initial hyperbranched poly(diallylcarbosilane) with DB = 0.5 and carbosilane dendrimer. It is shown that the solution properties of the pseudo‐dendrimer are close to those for the irregular hyperbranched polymer and differ significantly from the dendrimer behavior. Hence, it is branching regularity rather than the degree of branching that determines the conformational and hydrodynamic properties of hyperbranched polymers with a high degree of branching DB ≥ 0.5. © 2014 Society of Chemical Industry 相似文献
107.
Alina Amirova Serafim Rodchenko Mikhail Kurlykin Andrey Tenkovtsev Illia Krasnou Andres Krumme Alexander Filippov 《应用聚合物科学杂志》2021,138(3):49708
The cross-linked poly-2-isopropyl-2-oxazolines (PiPrOx) differing in cross-linker content have been synthesized and characterized by light scattering, chromatography, and rheometry. The dramatic influence of the cross-linker content on solubility and uni- or bimodality was observed. For the first time, the interpolymer complex of cross-linked PiPrOx with polyethylene oxide is manufactured in fibrous form by the electrospinning method. The role of intermolecular hydrogen bonds in the structure and properties of electrospun fibers (EF) was studied by infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. It was established that these interactions allow to obtain a uniform fibrous membrane. At the same time, hydrogen bonding is responsible for the self-organization of PiPrOx in water. 相似文献
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Oana Craciunescu Ana-Maria Seciu Vasile Sorin Manoiu Mihaela Trif Magdalena Moisei Alina Ioana Nicu 《Particulate Science and Technology》2019,37(6):753-759
Silver nanoparticles (AgNP) suspensions were biosynthesized by silver ions reduction in the presence of collagen, a nontoxic, organic polymer, intending to improve their medical use in periodontitis treatment. Spectrophotometric measurements showed a time- and concentration-dependent increase of AgNP formation in each suspension variant. Transmission electron microscopy revealed spherical morphology of AgNP in collagen and their mean diameter size was around 30?nm. The particle size distribution and zeta potential values of AgNP in collagen were determined by dynamic light scattering measurements. The surface charge of AgNP in collagen was positive, while commercial AgNP stabilized in citrate had negative surface charge. In vitro cytotoxicity testing of AgNP in collagen showed that they were biocompatible with human gingival fibroblasts in a wider range of concentrations than commercial nanoparticles. The antibacterial activity of AgNP in collagen against two pathogenic strains present in the periodontal pocket was dose-dependent and higher than that of AgNP in citrate. All these results demonstrated that AgNP prepared in collagen gel had improved properties, like small diameter, positive surface charge, high biocompatibility in human gingival fibroblasts, efficiency against bacterial growth and, thus, better therapeutic potential in periodontal disease treatment. 相似文献
110.
Coralia Cotoraci Alina Ciceu Alciona Sasu Anca Hermenean 《International journal of molecular sciences》2021,22(4)
Anemia, characterized by a decrease of the hemoglobin level in the blood and a reduction in carrying capacity of oxygen, is a major public health problem which affects people of all ages. The methods used to treat anemia are blood transfusion and oral administration of iron-based supplements, but these treatments are associated with a number of side effects, such as nausea, vomiting, constipation, and stomach pain, which limit its long-term use. In addition, oral iron supplements are poorly absorbed in the intestinal tract, due to overexpression of hepcidin, a peptide hormone that plays a central role in iron homeostasis. In this review, we conducted an analysis of the literature on biologically active compounds and plant extracts used in the treatment of various types of anemia. The purpose of this review is to provide up-to-date information on the use of these compounds and plant extracts, in order to explore their therapeutic potential. The advantage of using them is that they are available from natural resources and can be used as main, alternative, or adjuvant therapies in many diseases, such as various types of anemia. 相似文献