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排序方式： 共有941条查询结果，搜索用时 15 毫秒
891.
Baby AR Haroutiounian-Filho CA Sarruf FD Pinto CA Kaneko TM Velasco MV 《Drug development and industrial pharmacy》2009,35(3):272-282
Rutin, one of the major flavonoids found in an assortment of plants, was reported to act as a sun protection factor booster with high anti-UVA defense, antioxidant, antiaging, and anticellulite, by improvement of the cutaneous microcirculation. This research work aimed at evaluating the rutin in vitro release from semisolid systems, in vertical diffusion cells, containing urea, isopropanol and propylene glycol, associated or not, according to the factorial design with two levels with center point. Urea (alone and in association with isopropanol and propylene glycol) and isopropanol (alone and in association with propylene glycol) influenced significant and negatively rutin liberation in diverse parameters: flux (microg/cm(2).h); apparent permeability coefficient (cm/h); rutin amount released (microg/cm(2)); and liberation enhancement factor. In accordance with the results, the presence of propylene glycol 5.0% (wt/wt) presented statistically favorable to promote rutin release from this semisolid system with flux = 105.12 +/- 8.59 microg/cm(2).h; apparent permeability coefficient = 7.01 +/- 0.572 cm/h; rutin amount released = 648.80 +/- 53.01 microg/cm(2); and liberation enhancement factor = 1.21 +/- 0.07. 相似文献
892.
Low cycle fatigue, high cycle fatigue, fatigue crack propagation and thermo-mechanical fatigue in Ni-base superalloys are reviewed in terms of fundamental deformation mechanisms, environmental effects, and interactions between environment and deformation mode. These factors are related to the chemical composition and underlying microstructure for all currently-used product forms (i.e. powder metallurgy, wrought, conventionally cast and single crystal). The basic principles that are developed are used to show how both intrinsic and extrinsic variables can be manipulated to control fatigue behaviour and as a guide for formulation of engineering life prediction models. 相似文献
893.
Freitas Andre L. M. Tofanello Aryane Bonadio Ariany Souza Jose A. 《Journal of Materials Science: Materials in Electronics》2022,33(23):18327-18344
Journal of Materials Science: Materials in Electronics - We have investigated the role of H+, Bi3+, and Sb3+ ions incorporation on the structural, morphological, optical, and transport properties... 相似文献
894.
895.
After the discovery of illegal price agreements in the Dutch construction industry, the government and major players in the sector have initiated a transition process towards more professional commercial relations. In the transition process transparency plays an important part, as it is a precondition for better market operation in the construction sector. However, there are significant disadvantages to a pursuit of transparency, such as higher costs and the risk of information overload. It is therefore necessary to find a good balance between more transparency and other ways to restore trust between key players in the construction sector. Especially complex products with a high degree of risk can best be dealt with through implicit contracts, in which trust is based on a mixture of the reputation mechanism, contracts that create a congruity of interests and the integrity of the contract partners. 相似文献
896.
Muñoz Javier A Kreft O Piera Alberola A Kirchner C Zebli B Susha AS Horn E Kempter S Skirtach AG Rogach AL Rädler J Sukhorukov GB Benoit M Parak WJ 《Small (Weinheim an der Bergstrasse, Germany)》2006,2(3):394-400
We propose a combination of atomic force microscopy (AFM) and optical microscopy for the investigation of particle uptake by cells. Positively and negatively charged polymer microcapsules were chosen as model particles, because their interaction with cells had already been investigated in detail. AFM measurements allowed the recording of adhesion forces on a single-molecule level. Due to the micrometer size of the capsules, the number of ingested capsules could be counted by optical microscopy. The combination of both methods allowed combined measurement of the adhesion forces and the uptake rate for the same model particle. As a demonstration of this system, the correlation between the adhesion of positively or negatively charged polymer microcapsules onto cell surfaces and the uptake of these microcapsules by cells has been investigated for several cell lines. As is to be expected, we find a correlation between both processes, which is in agreement with adsorption-dependent uptake of the polymer microcapsules by cells. 相似文献
897.
Bregt Verreet Paul Heremans Andre Stesmans Barry P. Rand 《Advanced materials (Deerfield Beach, Fla.)》2013,25(38):5504-5507
898.
899.
Bat‐El Pinchasik Helmuth Möhwald Andre G. Skirtach 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(13):2670-2677
Bubbles are widely used by animals in nature in order to fulfill important functions. They are used by animals in order to walk underwater or to stabilize themselves at the water/air interface. The main aim of this work is to imitate such phenomena, which is the essence of biomimetics. Here, bubbles are used to propel and to control the location of Janus particles in an aqueous medium. The synthesis of Janus SiO2‐Ag and polystyrene‐Ag (PS‐Ag) particles through embedment in Parafilm is presented. The Janus particles, partially covered with catalytically active Ag nanoparticles, are redispersed in water and placed on a glass substrate. The active Ag sites are used for the splitting of H2O2 into water and oxygen. As a result, an oxygen bubble is formed on one side of the particle and promotes its propulsion. Once formed, the bubble‐particle complex is stable and therefore, can be manipulated by tuning hydrophilic‐hydrophobic interactions with the surface. In this way a transition between two‐ and three‐ dimensional motion is possible by changing the hydrophobicity of the substrate. Similar principles are used in nature. 相似文献
900.
Bat‐El Pinchasik Klaus Tauer Helmuth Mhwald Andre G. Skirtach 《Advanced Materials Interfaces》2014,1(2)
The group of silanes is one of the most abundant classes of molecules used for surface modification. In most studies, silanization is made from the vapor phase or solution. Here, an easy, robust, and fast way not only to modify, but also to map, control, and predict the wetting profiles on silicon surfaces after silanization and the final characteristics of a brush layer polymerized from this silane template profile are presented. The initiator molecule, 2‐bromo‐2‐methyl‐N‐3‐(triethoxysilyl) propyl propanamide (BTPAm), is spin‐casted on a silicon substrate and a thermal gradient is applied using a combinatorial approach for studying the influence of temperature on the spin‐casted silanes. Subsequently, polyacrylamide (PAAm) brushes are grown from the initiating end group of the BTPAm molecules through atom transfer radical polymerization (ATRP). Simulations of the heat distribution inside the silicon wafer allow both confirming the mapping of surface properties and designing desired profiles by predicting thermal distributions. An analytical expression for quantification is also provided. Thus, the wetting properties, surface roughness, and morphology of the brush layer after polymerization are mapped and correlated with the initial BTPAm gradient profile. The studies presented are envisioned to be of interest for designing surface profiles with different wetting properties, facilitating polymer brush growth, and to be used as predictive tools. 相似文献