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排序方式: 共有330条查询结果,搜索用时 718 毫秒
51.
Adam Wichniak Aleksander Kania Mariusz Siemiski Wiesaw Jerzy Cubaa 《International journal of molecular sciences》2021,22(16)
Melatonin is registered to treat circadian rhythm sleep–wake disorders and insomnia in patients aged 55 years and over. The essential role of the circadian sleep rhythm in the deterioration of sleep quality during COVID-19 confinement and the lack of an adverse effect of melatonin on respiratory drive indicate that melatonin has the potential to be a recommended treatment for sleep disturbances related to COVID-19. This review article describes the effects of melatonin additional to its sleep-related effects, which make this drug an attractive therapeutic option for treating patients with COVID-19. The preclinical data suggest that melatonin may inhibit COVID-19 progression. It may lower the risk of the entrance of the SARS-CoV-2 virus into cells, reduce uncontrolled hyper-inflammation and the activation of immune cells, limit the damage of tissues and multiorgan failure due to the action of free radicals, and reduce ventilator-induced lung injury and the risk of disability resulting from fibrotic changes within the lungs. Melatonin may also increase the efficacy of COVID-19 vaccination. The high safety profile of melatonin and its potential anti-SARS-CoV-2 effects make this molecule a preferable drug for treating sleep disturbances in COVID-19 patients. However, randomized clinical trials are needed to verify the clinical usefulness of melatonin in the treatment of COVID-19. 相似文献
52.
53.
Slomkowski S Gadzinowski M Sosnowski S Radomska-Galant I Pucci A De Vita C Ciardelli F 《Journal of nanoscience and nanotechnology》2006,6(9-10):3242-3251
Polylactide-b-polyglycidol-b-poly(ethylene oxide) terpolymers and their derivatives with carboxyl and 4-(phenylazo)phenyl labels in polyglycidol blocks were used for formation of nanoparticles. Nanoparticles were produced by self assembly of terpolymer macromolecules in water above the critical aggregation concentration and by dialysis of terpolymer solutions in 1,4-dioxane against water. For terpolymers with 4-(phenylazo)phenyl labels critical aggregation concentrations increased after irradiation with UV light (300 < lambda < 400 nm) inducing conformational change of the label from trans- to cis-conformation. Diameters of nanoparticles obtained by self-assembly of macromolecules ranged from 20 to 44 nm. Dialysis yielded nanoparticles with bimodal diameter distribution. One fraction had diameters below 35 nm and diameters of the second fraction were in a range from 350 to 2300 nm, depending on terpolymer structure. Mixtures of terpolymers with poly(L,L-lactide) and poly(D,D-lactide) blocks yielded nanoparticles with diameters from 350 to 440 nm. Pyrene was incorporated into nanoparticles by partition between solution and nanoparticles or directly during particle formation by dialysis. Monitoring of pyrene release from nanoparticles suggests that a fraction of this compound was entrapped into the polylactide core whereas the remaining one was located in the polyether rich shell. The release from shells is faster for nanoparticles made from copolymers with carboxyl labels in polyglycidol blocks. 相似文献
54.
Mariusz Ciesielski Bohdan Mochnacki 《Numerical Heat Transfer, Part A: Applications》2013,63(11):1685-1700
AbstractThe numerical modeling of thermal processes in domain of biological tissue (the male thigh) secured by multilayered protective clothing being in the thermal contact with the environment is discussed. The thigh is treated as the nonhomogeneous domain in which the sub-domains of skin tissue, fat, muscle, bone and blood vessels are distinguished. Between the protective clothing and skin tissue the air gap is taken into account. The heat transfer is described by the system of hyperbolic Cattaneo–Vernotte equations (for the tissue sub-domains) and parabolic Fourier equations (for the remaining sub-domains). The process of external heating is determined by the appropriate boundary condition and the internal heat source (in the fabric sub-domain) related to the absorption of incident thermal radiation. The mathematical model is solved numerically using the control volume method, while the considered sub-domains (the 2?D problem) are covered by the Voronoi meshes. In the final part of the article, the example of computations is presented. 相似文献
55.
The aim of the study was to check the quality of gluten-free bread produced basing on the recipes, in which part of native starch was replaced with high amylose corn starch (HACS), acetylated distarch adipate (ADA), and hydroxypropyl distarch phosphate (HDP). The application 10 or 15% of chemically modified starches (HDP, ADA) caused the increase in volume of the obtained gluten-free loaves. The changes were accompanied by a decrease of average cell size, and an increase in their number. Due to the addition of modified starch crumb structure became more elastic, which was revealed in the results of stress relaxation. A slight decrease in hardness and chewiness of the crumb was also observed on the day of baking, and its extent depended on the level of modified starch, and was a little more pronounced in case of starch adipate. In comparison to the chemically modified starches, HACS deteriorated structural and mechanical properties of the crumb, which is probably related to their resistance to pasting and divergence in retrogradation pattern, where amylose component is more important than amylopectin. 相似文献
56.
This article presents a new lake district in Southern Poland created as a result of human activity in the Upper Silesian region. The area has been named the Upper Silesian Anthropogenic Lake District. The lake density of the Lake District as delineated by the authors (with an area of 6766 km2) is 2.74%. It includes 4773 water bodies of various origins – reservoirs retained by dams, flooded mineral workings, water bodies formed in subsidence basins and hollows, levee ponds, residual water bodies following river regulation and other water bodies. These are located in urban‐industrial, rural‐agricultural or quasi‐natural areas. The hydrochemical diversity of water bodies is conditioned by their origin, location in the catchment and function. Studies have shown the widespread occurrence of eutrophication processes in limnic waters within the Lake District. The diverse origin and hydrochemical properties of water bodies within the Upper Silesian Anthropogenic Lake District make it special among other anthropogenic lake districts. 相似文献
57.
Agnieszka Iwan Marcin Palewicz Mariusz Ozimek Andrzej Chuchmala Grzegorz Pasciak 《Organic Electronics》2012,13(11):2525-2531
The main goal of the paper was investigation of influence of aluminum electrode preparation via thermal evaporation (TE) and the magnetron sputtering (MS) on power conversion efficiency (PCE) of polymeric solar cells. The photovoltaic properties of such three kinds devices based on poly(3-hexylthiophene-2,5-diyl) (P3HT) as ITO/P3HT/Al, ITO/P3HT:PCBM (1:1, w/w)/Al and ITO/PEDOT:PSS/P3HT:PCBM (1:1, w/w)/Al were investigated. For the constructed devices impedance spectroscopy were analyzed. For devices lack of PEDOT:PSS layer or lack of PCBM, photovoltaic parameters were very low and similar to the parameters obtained for device with Al electrode prepared by magnetron sputtering. The devices comprising PEDOT:PSS with P3HT:PCBM showed the best photovoltaic parameters such as a VOC of 0.60 V, JSC of 4.61 mA/cm2, FF of 0.21, and PCE of 5.7 × 10?1%. 相似文献
58.
Bartomiej Bachowski Andrzej
wiercz Mariusz Ostrowski Piotr Tauzowski Piotr Olaszek ukasz Jankowski 《Computer-Aided Civil and Infrastructure Engineering》2020,35(10):1085-1100
This paper proposes a computationally effective framework for load‐dependent optimal sensor placement in large‐scale civil engineering structures subjected to moving loads. Two common problems are addressed: selection of modes to be monitored and computational effectiveness. Typical sensor placement methods assume that the set of modes to be monitored is known. In practice, determination of such modes of interest is not straightforward. A practical approach is proposed that facilitates the selection of modes in a quasi‐automatic way based on the structural response at the candidate sensor locations to typical operational loads. The criterion used to assess sensor placement is based on Kammer's Effective Independence (EFI). However, in contrast to typical implementations of EFI, which treat the problem as a computationally demanding discrete problem and use greedy optimization, an approach based on convex relaxation is proposed. A notion of sensor density is applied, which converts the original combinatorial problem into a computationally tractable continuous optimization problem. The proposed framework is tested in application to a real tied‐arch railway bridge located in central Poland. 相似文献
59.
Michał Piotr Kwiatkowski Mariusz Kłonica Józef Kuczmaszewski Saburoh Satoh 《臭氧:科学与工程》2013,35(3):220-228
The purpose of this article is to present energetic properties of surface Ti6Al4V titanium as well as surface EN-AW-2017A(PA6) aluminum alloy layers. Values of surface free energy after selected mechanical operations and ozonation were compared. In addition, the influence of different values of ozone concentration on surface layer energetic activation was analyzed. Dispersive and polar components of surface free energy were of particular concern. Comparative evaluation of shearing strength of Ti6Al4V titanium and EN-AW-2017A(PA6) aluminum alloy single-lap adhesive bonded joints were presented. Results can be used as pro-ecological methods of titanium and aluminum alloys preparing for applications where adhesive phenomenon is important. 相似文献
60.
A conceptual factory to produce hydrogen from starchy biomass is considered. The production plant comprises a pretreatment unit for starchy raw material, a bioreactor for dark fermentation, a photobioreactor for photofermentation and gas upgrading & compression units, and is supplied with the necessary heat and power from the power plant. In the power plant, a part of the stream of raw gas produced in bioreactors is burned in a steam boiler and in addition some product gas from the upgrading unit is directed to fuel cells from which waste gas flows to a catalytic oxidizer. The demand for process heat is covered by steam generation in the boiler and oxidizer, and the power demand is covered by electricity generation in the fuel cells. 相似文献