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Relevant data on heterogeneous surface recombination of neutral oxygen atoms available in the scientific literature are reviewed and discussed for various materials. The coefficients are determined by placing the samples either in non-equilibrium oxygen plasma or its afterglow. The experimental methods used to determine the coefficients are examined and categorized into calorimetry, actinometry, NO titration, laser-induced fluorescence, and various other methods and their combinations. Some numerical models for recombination coefficient determination are also examined. Correlations are drawn between the experimental parameters and the reported coefficients. Different materials are examined and categorized according to reported recombination coefficients into catalytic, semi-catalytic, and inert materials. Measurements from the literature of the recombination coefficients for some materials are compiled and compared, along with the possible system pressure and material surface temperature dependence of the materials’ recombination coefficient. A large scattering of results reported by different authors is discussed, and possible explanations are provided. Full article

Ti₃C₂T_x (T = OH) was first prepared from Ti₃AlC₂ by HF etching and applied into a photocatalytic CO₂ reduction. Then, the Ti₃C₂T_x nanosheets present interbedded a self-supporting structure and extended interlayer spacing. Meanwhile, the Ti₃C₂T_x nanosheets are decorated with abundant oxygen-containing functional groups in the process of etching, which not only serve as active sites but also show efficient charge migration and separation. Among Ti₃C₂T_x materials prepared by etching for different times, Ti₃C₂T_x-36 (Etching time: 36 h) showed the best performance for photoreduction of CO₂ into alcohols (methanol and ethanol), giving total yield of 61 μmol g catal.⁻¹, which is 2.8 times than that of Ti₃AlC₂. Moreover, excellent cycling stability for CO₂ reduction is beneficial from the stable morphology and crystalline structure. This work provided novel sights into constructing surface active sites controllably. Full article

Curcumin (diferuloylmethane) is found in the rhizomes of the turmeric plant (Curcuma longa L.) and has been used for centuries as a dietary spice and as a traditional Indian medicine used to treat different conditions. At the cellular level, curcumin modulates important molecular targets: transcription factors, enzymes, cell cycle proteins, cytokines, receptors and cell surface adhesion molecules. Because many of the curcumin targets mentioned above participate in the regulation of bone remodeling, curcumin may affect the skeletal system. Nitric oxide (NO) is a gaseous molecule generated from L-arginine during the catalization of nitric oxide synthase (NOS), and it plays crucial roles in catalization and in the nervous, cardiovascular and immune systems. Human osteoblasts have been shown to express NOS isoforms, and the exact mechanism(s) by which NO regulates bone formation remain unclear. Curcumin has been widely described to inhibit inducible nitric oxide synthase expression and nitric oxide production, at least in part via direct interference in NF-κB activation. In the present study, after exposure of human osteoblast-like cells (MG-63), we have observed that curcumin abrogated inducible NOS expression and decreased NO levels, inhibiting also cell prolifieration. This effect was prevented by the NO donor sodium nitroprusside. Under osteogenic conditions, curcumin also decreased the level of mineralization. Our results indicate that NO plays a role in the osteoblastic profile of MG-63 cells. Full article