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Osteoarthritis (OA) is the most common cause of musculoskeletal pain and disability. The importance of chondrocytes in the pathogenesis of OA is unequivocal. 17β-estradiol (E2) has a potential protective effect against OA. However, the mechanism of E2 in OA chondrocytes remains unclear. In this study, we investigated the regulative effect of E2 on cell growth and the relationship between E2 and the PI3K/Akt pathway in rat OA model chondrocytes (pretreated with interleukin-1β). We found that E2 induced chondrocyte proliferation, and increased the expression level of Akt simultaneously, especially the expression level of P-Akt. Furthermore, the inhibition of P-Akt could block chondrocyte proliferation induced by E2. These results suggest that PI3K/Akt activation induced by E2 may be an important factor in the mechanism of E2 in cell proliferation in rat OA model chondrocytes, and help further understanding the role of E2 in OA progression.

Large organolead triiodide perovskite (OTP) grains with little intragranular defects are beneficial to minimize carrier recombination, hence boosting cell performance. However, OTP films deposited by the widely used one-step spin-coating route are usually composed of small grains, because the poor thermal stability of OTP inherently restricts the processing window (temperature, time) during the film preparation, thus limiting grain coarsening in the film. Herein, the remarkable grain coarsening via Ostwald ripening in one-step deposited OTP films has been successfully realized by a facile and effective post-synthesis high-temperature heating treatment assisted with spin-coated CH3NH3I. By systematically investigating the heating treatment parameters, a high-quality OTP film with an enlarged average grain size from ∼280 nm to 1.2 μm, greatly enhanced crystallinity, and excellent stoichiometry is achieved. Benefiting from such improved features, this modified film shows significantly reduced defect states corresponding to the decrease of recombination centers, as well as enhanced carrier transport and injection properties, which lead to the dramatically boosted efficiency from 14.54% to 16.88% for planar-heterojunction solar cells. More importantly, the improved OTP film quality provides the possibility of thickening the absorber layer of cells to realize more sufficient absorption without serious aggravation of charge recombination. By further optimizing the thickness of the coarsened OTP films, highly efficient cells with relatively excellent reproducibility and an optimal efficiency of 19.24% are achieved.

Ultralow density (approximately 10(6)/cm(2)) of twin InAs quantum dot (QD) hybrid structure was grown by a droplet epitaxy technique. The photoluminescence (PL) from ensemble and individual twin InAs QD structures showed a bimodal behavior and an energy transfer between the well-separated (approximately 190 nm) twin QDs, which was supposedly due to the special wetting ring that built the channel for exciton transfer. This research demonstrates a novel approach to fabricate lateral InAs QD pairs as the candidate for a laterally coupled QD molecule.

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Ground granulated blast furnace slag is widely used as a mineral admixture to replace partial Portland cement in the concrete industry. As the amount of slag increases, the late-age compressive strength of concrete mixtures increases. However, after an optimum point, any further increase in slag does not improve the late-age compressive strength. This optimum replacement ratio of slag is a crucial factor for its efficient use in the concrete industry. This paper proposes a numerical procedure to analyze the optimum usage of slag for the compressive strength of concrete. This numerical procedure starts with a blended hydration model that simulates cement hydration, slag reaction, and interactions between cement hydration and slag reaction. The amount of calcium silicate hydrate (CSH) is calculated considering the contributions from cement hydration and slag reaction. Then, by using the CSH contents, the compressive strength of the slag-blended concrete is evaluated. Finally, based on the parameter analysis of the compressive strength development of concrete with different slag inclusions, the optimum usage of slag in concrete mixtures is determined to be approximately 40% of the total binder content. The proposed model is verified through experimental results of the compressive strength of slag-blended concrete with different water-to-binder ratios and different slag inclusions. OPEN ACCESSMaterials 2015, 8 1214

Portland cement is the most widely used cement in the world. To contribute to the sustainability of the construction industry, industrial by-products from the combustion of coal, such as fly ash, are being widely used as mineral admixtures in normal and high-strength concretes. Owing to the pozzolanic reaction between calcium hydroxide and fly ash, the hydration of cement containing fly ash is much more complex than that of Portland cement. By considering the production of calcium hydroxide in cement hydration and its consumption in the pozzolanic reaction, a numerical procedure is proposed to simulate the hydration of concrete containing fly ash. The numerical procedure includes two sub-components -a cement hydration model and a fly ash reaction model. The heat evolution rate of fly ash concrete is determined from the contributions of the cement hydration and the pozzolanic reaction.Furthermore, the temperature history in hardening blended concrete is evaluated by combining the proposed numerical procedure with a finite-element method. The proposed model is verified through experimental data on concrete with different water to cement ratios and mineral admixture substitution ratios.

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