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排序方式: 共有223条查询结果,搜索用时 15 毫秒
111.
This paper describes a new multilevel procedure that can solve the discrete Navier–Stokes system arising from finite volume discretizations on composite grids, which may consist of more than one level. SIMPLE is used and tested as the smoother, but the multilevel procedure is such that it does not exclude the use of other smoothers. Local refinement is guided by a criterion based on an estimate of the truncation error. The numerical experiments presented test not only the behaviour of the multilevel algebraic solver, but also the efficiency of local refinement based on this particular criterion. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
112.
Gurunath Apte Alexandros Repanas Christian Willems Anas Mujtaba Christian E. H. Schmelzer Ashok Raichur Frank Syrowatka Thomas Groth 《Macromolecular bioscience》2019,19(11)
Freestanding multilayer films prepared by layer‐by‐layer technique have attracted interest as promising materials for wound dressings. The goal is to fabricate freestanding films using chitosan (CHI) and alginate (ALG) including subsequent crosslinking to improve the mechanical properties of films while maintaining their biocompatibility. Three crosslinking strategies are investigated, namely use of calcium ions for crosslinking ALG, 1‐ethyl‐3‐(‐3‐dimethylaminopropyl) carbodiimide combined with N‐hydroxysuccinimide for crosslinking ALG with CHI, and Genipin for crosslinking chitosan inside the films. Different characteristics, such as surface morphology, wettability, swelling, roughness, and mechanical properties are investigated showing that films became thinner, exhibited rougher surfaces, had lower water uptake, and increased mechanical strength after crosslinking. Changes of wettability are moderate and dependent on the crosslinking method. In vitro cytotoxicity and cell attachment studies with human dermal fibroblasts show that freestanding CHI‐ALG films represent a poorly adhesive substratum for fibroblasts, while studies using incubation of plastic‐adherent fibroblast beneath floating films show no signs of cytotoxicity in a time frame of 7 days. Results from cell experiments combined with film characteristics after crosslinking, indicate that crosslinked freestanding films made of ALG and CHI may be interesting candidates for wound dressings. 相似文献
113.
Basma G. Eid Thikryat Neamatallah Abeer Hanafy Hany M. El-Bassossy Lenah Binmahfouz Hibah M. Aldawsari Atif Hasan Gamal Abd El-Aziz Kiran Vemuri Alexandros Makriyannis 《Molecules (Basel, Switzerland)》2021,26(4)
The role of cannabinoid receptors in nephropathy is gaining much attention. This study investigated the effects of two neutral CB1 receptor antagonists, AM6545 and AM4113, on nephropathy associated with metabolic syndrome (MetS). MetS was induced in rats by high-fructose high-salt feeding for 12 weeks. AM6545, the peripheral silent antagonist and AM4113, the central neutral antagonist were administered in the last 4 weeks. At the end of study, blood and urine samples were collected for biochemical analyses while the kidneys were excised for histopathological investigation and transforming growth factor beta 1 (TGFβ1) measurement. MetS was associated with deteriorated kidney function as indicated by the elevated proteinuria and albumin excretion rate. Both compounds equally inhibited the elevated proteinuria and albumin excretion rate while having no effect on creatinine clearance and blood pressure. In addition, AM6545 and AM4113 alleviated the observed swelling and inflammatory cells infiltration in different kidney structures. Moreover, AM6545 and AM4113 alleviated the observed histopathological alterations in kidney structure of MetS rats. MetS was associated with a ten-fold increase in urine uric acid while both compounds blocked this increase. Furthermore, AM6545 and AM4113 completely prevented the collagen deposition and the elevated expression of the TGFβ1 seen in MetS animals. In conclusion, AM6545 and AM4113, possess reno-protective effects by interfering with TGFβ1-mediated renal inflammation and fibrosis, via peripheral action. 相似文献
114.
Patrick Hoffmann Ricardo P. Mikalo Alexandros Yfantis David R. Batchelor Guenter Appel Dimitrios Yfantis Dieter Schmeißer 《Mikrochimica acta》2001,136(3-4):109-113
Synchrotron radiation based spectro-microscopy is shown to be an exciting tool for elemental analysis in the field of heterogeneous
interfaces, thin films, and device technology. Results are reported, taken with a spectrometer that enables the combination
of a photoemission electron microscope (PEEM) with photoelectron spectroscopies (XPS, UPS) operated at a high brilliance undulator
beam line at BESSY.
The properties of mc-Si (multi crystalline silicon) are of interest because of their applications in low priced photovoltaic
devices. An example of how to analyze the surface potentials of such surfaces without removing the native oxide is given.
Tin nano-scale particles are shown to be the decisive factor affecting the corrosion prevention of passivated tinplate surfaces. 相似文献
115.
Aspirin triggers the biosynthesis of oxygenated metabolites from arachidonic, eicosapentaenoic, and docosahexaenoic (DHA) acids. In a preceding issue, Serhan et?al. (2011) describe a novel aspirin-triggered DHA pathway for the biosynthesis of a potent anti-inflammatory and proresolving molecule. 相似文献
116.
Athanasia Kostopoulou Ioannis Tsiaoussis Alexandros Lappas 《Photonics and Nanostructures》2011,9(2):201-206
We have developed a modified synthetic protocol for the growth of monodispersed, superparamagnetic, flower-like colloidal nanoclusters (CNCs), which are consisted of smaller iron oxide nanocrystals with adjustable size. We show that their optical properties can be tuned by applying an external magnetic field. The latter controls the subtle balance of the CNCs’ mutual interactions (magnetic versus electrostatic) and drives their assembly in aqueous media. Spectrophotometric measurements reveal that a diffuse reflectance maximum, in the visible range, is related to the CNCs organization. As the strength of the external magnetic field increases, in the range 160–600 G, the spectral weight of this feature shifts towards the blue region of the spectrum. The induced photonic crystal-like response entails a remarkable magneto-optical behavior, closely associated with the size-dependent characteristics of the CNCs ensemble. Such materials pave the way for promising technological implementations in photonics. 相似文献
117.
We provide benchmark results for a transient variant of the lid-driven cavity problem, where the lid motion is suddenly stopped and the flow is left to decay under the action of viscosity. Results include Newtonian as well as Bingham flows, the latter having finite cessation times, for Reynolds numbers Re ∈ [1, 1000] and Bingham numbers Bn ∈ [0, 10]. The finite-volume method and Papanastasiou regularisation were employed. A combination of Re and Bn, the effective Reynolds number, is shown to convey more information about the flow than either Re or Bn alone. A time scale which characterises the flow independently of the geometry and flow parameters is proposed. 相似文献
118.
119.
Esther Rebollar Giannis Bounos Alexandros Selimis Marta Castillejo Savas Georgiou 《Applied Physics A: Materials Science & Processing》2008,92(4):1043-1046
Following previous studies on the influence of the polymer molecular weight (MW) on the ablation of poly(methyl methacrylate) (PMMA) at 248 nm, this work extends the examination to the ablation of polystyrene
(PS) at 248 nm. The ablation threshold and the etching rates are found to be nearly independent of MW. Optical microscopy demonstrates an excellent crater morphology, few small bubbles are formed on the surface of the low MW. Examination of the formation kinetics of products in the irradiation of samples doped with the photoreactive iodophenanthrene
demonstrates that high temperatures develop upon irradiation, suggesting that thermal mechanism dominates in the ablation
of PS at 248 nm. In similarity to the etching rates, the attained temperatures are largely independent of the PS MW. The factors for the weak dependence of the process on PS MW are discussed. 相似文献
120.