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101.
Mingming Tong Gregory Duggan Jun Liu Yu Xie Mike Dodge Lee Aucott Hongbiao Dong Ruslan L. Davidchack Jon Dantzig Olga Barrera Alan C.F. Cocks Hiroto Kitaguchi Sergio Lozano-Perez Chuangxin Zhao Ian Richardson Anton Kidess Chris R. Kleijn Shuwen Wen Roger Barnett David J. Browne 《JOM Journal of the Minerals, Metals and Materials Society》2013,65(1):99-106
Various physical interfacial phenomena occur during the process of welding and influence the final properties of welded structures. As the features of such interfaces depend on physics that resolve at different spatial scales, a multiscale and multiphysics numerical modeling approach is necessary. In a collaborative research project Modeling of Interface Evolution in Advanced Welding, a novel strategy of model linking is employed in a multiscale, multiphysics computational framework for fusion welding. We only directly link numerical models that are on neighboring spatial scales instead of trying to link all submodels directly together through all available spatial scales. This strategy ensures that the numerical models assist one another via smooth data transfer, avoiding the huge difficulty raised by forcing models to attempt communication over many spatial scales. Experimental activities contribute to the modeling work by providing valuable input parameters and validation data. Representative examples of the results of modeling, linking and characterization are presented. 相似文献
102.
We have shown that autoxidized polyphenolic nutraceuticals oxidize H2S to polysulfides and thiosulfate and this may convey their cytoprotective effects. Polyphenol reactivity is largely attributed to the B ring, which is usually a form of hydroxyquinone (HQ). Here, we examine the effects of HQs on sulfur metabolism using H2S- and polysulfide-specific fluorophores (AzMC and SSP4, respectively) and thiosulfate sensitive silver nanoparticles (AgNP). In buffer, 1,4-dihydroxybenzene (1,4-DB), 1,4-benzoquinone (1,4-BQ), pyrogallol (PG) and gallic acid (GA) oxidized H2S to polysulfides and thiosulfate, whereas 1,2-DB, 1,3-DB, 1,2-dihydroxy,3,4-benzoquinone and shikimic acid did not. In addition, 1,4-DB, 1,4-BQ, PG and GA also increased polysulfide production in HEK293 cells. In buffer, H2S oxidation by 1,4-DB was oxygen-dependent, partially inhibited by tempol and trolox, and absorbance spectra were consistent with redox cycling between HQ autoxidation and H2S-mediated reduction. Neither 1,2-DB, 1,3-DB, 1,4-DB nor 1,4-BQ reduced polysulfides to H2S in either 21% or 0% oxygen. Epinephrine and norepinephrine also oxidized H2S to polysulfides and thiosulfate; dopamine and tyrosine were ineffective. Polyphenones were also examined, but only 2,5-dihydroxy- and 2,3,4-trihydroxybenzophenones oxidized H2S. These results show that H2S is readily oxidized by specific hydroxyquinones and quinones, most likely through the formation of a semiquinone radical intermediate derived from either reaction of oxygen with the reduced quinones, or from direct reaction between H2S and quinones. We propose that polysulfide production by these reactions contributes to the health-promoting benefits of polyphenolic nutraceuticals. 相似文献
103.
104.
Viktoriya Rumyantceva Valeriya Rumyantceva Yulia Andreeva Sofia Tsvetikova Anton Radaev Maria Vishnevskaya Vladimir Vinogradov Andrey S. Drozdov Elena Koshel 《International journal of molecular sciences》2021,22(12)
Biofilms are the reason for a vast majority of chronic inflammation cases and most acute inflammation. The treatment of biofilms still is a complicated task due to the low efficiency of drug delivery and high resistivity of the involved bacteria to harmful factors. Here we describe a magnetically controlled nanocomposite with a stimuli-responsive release profile based on calcium carbonate and magnetite with an encapsulated antibiotic (ciprofloxacin) that can be used to solve this problem. The material magnetic properties allowed targeted delivery, accumulation, and penetration of the composite in the biofilm, as well as the rapid triggered release of the entrapped antibiotic. Under the influence of an RF magnetic field with a frequency of 210 kHz, the composite underwent a phase transition from vaterite into calcite and promoted the release of ciprofloxacin. The effectiveness of the composite was tested against formed biofilms of E. coli and S. aureus and showed a 71% reduction in E. coli biofilm biomass and an 85% reduction in S. aureus biofilms. The efficiency of the composite with entrapped ciprofloxacin was higher than for the free antibiotic in the same concentration, up to 72%. The developed composite is a promising material for the treatment of biofilm-associated inflammations. 相似文献
105.
Lauryna Sinusaite Anton Popov Eva Raudonyte-Svirbutaviciene Jen-Chang Yang Aivaras Kareiva Aleksej Zarkov 《Ceramics International》2021,47(9):12078-12083
In the present work, effect of Mn doping on hydrolysis rate of low-temperature synthesized metastable α-tricalcium phosphate (α-TCP) was investigated. α-TCP powders containing different amount of Mn2+ ions (0, 0.5 and 1 mol%) were synthesized by wet co-precipitation process, followed by annealing and crystallization of as-precipitated amorphous calcium phosphate at 700 °C. It was demonstrated that the presence of Mn2+ ions significantly retards hydrolysis rate of α-TCP. While pristine α-TCP fully hydrolyzed with a conversion to calcium-deficient hydroxyapatite in 10 h, complete hydrolysis of α-TCP doped with 0.5 and 1 mol% of Mn occurred only after 20 and 35 h, respectively. Initial and final products were characterized by X-ray diffraction (XRD) analysis, infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Chemical composition of starting and fully hydrolyzed α-TCP powders was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). 相似文献
106.
107.
Joachim Mittendorf Prof. Dr. Stefan Weigand Dr. Cristina Alonso‐Alija Dr. Erwin Bischoff Dr. Achim Feurer Dr. Michael Gerisch Dr. Armin Kern Dr. Andreas Knorr Dr. Dieter Lang Dr. Klaus Muenter Dr. Martin Radtke Dr. Hartmut Schirok Dr. Karl‐Heinz Schlemmer Dr. Elke Stahl Dr. Alexander Straub Dr. Frank Wunder Dr. Johannes‐Peter Stasch Dr. 《ChemMedChem》2009,4(5):693-693
108.
Anton Trník Igor Štubňa Jana Moravčíková 《International Journal of Thermophysics》2009,30(4):1323-1328
The sound velocity of Sedlec kaolin during heating from 20 °C to 1100 °C was investigated by modulated force thermomechanical
analysis (mf-TMA). In the interval from 20 °C to 250 °C, the sound velocity increases which can be explained by liberation
of the water molecules from pores and micropores. Dehydroxylation (450 °C to 650 °C) presents itself with a decrease of the
sound velocity. After dehydroxylation, a two-step increase of the sound velocity was observed. The first step of the increase
of the sound velocity is due to solid-state sintering at low temperatures. The second step starts at 950 °C as a consequence
of the collapse of the metakaolinite structure. After the maximum, a steep increase of the sound velocity follows as a result
of solid-state sintering. 相似文献
109.
Miks A 《Journal of the Optical Society of America. A, Optics, image science, and vision》2002,19(9):1867-1871
New parameters for calculation of third-order aberration coefficients (Seidel aberration coefficients) are introduced. The formulas for Seidel aberration coefficients are linear in these new variables. With these new variables it is possible to calculate the shape and the refractive index of the glass of the individual lenses of the optical system, which was not possible before. 相似文献
110.
The optical constants of thin films of CsI, KI, and KBr and the quantum efficiency (QE) of planar photocathodes made with these alkali halides in the 53.6-174.4-nm spectral range are presented. The optical constants were obtained from measurements of the reflectance as a function of incidence angle. The effect of film heating and exposure to UV irradiation on the optical properties and on the QE of the three alkali halides was investigated. KBr was found to be the most stable material for both heating and UV irradiation. KI appeared to be close to temperature stable, whereas UV exposure affected its optical constants. CsI optical constants changed after 420 K heating and after UV exposure. The changes in the optical constants were related to the QE changes, and a certain correlation between both variations was determined. However, it was also demonstrated that the QE changes cannot be explained solely by the changes in optical constants. 相似文献