ObjectivesObesity is suggested to be a risk factor for knee osteoarthritis (OA). This meta-analysis aimed to examine the relationship between body mass index (BMI) and the risk of knee OA in published prospective studies.DesignMeta-analysis.Studies reviewedAn extensive literature review was performed, and relevant studies published in English were retrieved from the computerised databases MEDLINE, EMBASE and Cochrane.MethodsThe effect estimate (RR or HR) and its 95% CI are investigated on the basis of the evaluation of differences of knee OR risk in overweight or obesity versus those with normal weight. Category-specific risk estimates were further transformed into estimates of the RR in terms of per increase of 5 in BMI by using the generalised least-squares method for trend estimation. Studies were independently reviewed by two investigators. Subgroup analysis was performed. Heterogeneity and publication bias were assessed. Data from eligible studies were extracted, and the meta-analysis was performed by using the STATA software V.12.0.Results14 studies were finally included in the analysis. The results showed that overweight and obesity were significantly associated with higher knee OA risks of 2.45 (95% CI 1.88 to 3.20, p<0.001) and 4.55 (95% CI 2.90 to 7.13, p<0.001), respectively. The risk of knee OA increases by 35% (95% CI 1.18 to 1.53, p<0.001) with a 5 kg/m2 increase in BMI. Subgroup analysis showed that obesity was an independent predictor of knee OA risk regardless of the study country, sample size, gender proportion of participants, duration of follow-up, presence of adjusted knee injury and assessed study quality above or below an NOS score of 8. No publication bias was detected.ConclusionsObesity was a robust risk factor for knee OA. Professionals should take a possible weight reduction into account for the treatment of knee OA whenever a patient is significantly overweight.

[1] Recent comparisons between satellite observed and global model simulated glyoxal (CHOCHO) have consistently revealed a large unknown source of CHOCHO over China. We examine this missing CHOCHO source by analyzing SCIAMACHY observed CHOCHO vertical column densities (VCDs) using a Regional chEmical trAnsport Model (REAM). This missing source is first quantified by the difference between SCIAMACHY observed and REAM simulated CHOCHO VCDs (DC CHOCHO ), which have little overlap with high biogenic isoprene emissions but are collocated with dense population and high anthropogenic NO x and VOC emissions. We then apply inverse modeling to constrain CHOCHO precursor emissions based on SCIAMACHY CHOCHO and find that this missing source is most likely caused by substantially underestimated aromatics emissions (by a factor of 4-10, varying spatially) in the VOC emission inventories over China used in current regional and global models. Comparison with in situ observations in Beijing, Shanghai, and a site in the Pearl River Delta shows that the large model biases in aromatics concentrations are greatly reduced after the inversion. The top-down estimated aromatics emission is 13.4 Tg yr À1 in total, about 6 times the bottom-up estimate (2.4 Tg yr À1 ). The resulting impact on regional oxidant levels is large (e.g., $100% increase of PAN in the afternoon). Furthermore, since aromatics are important precursors of secondary organic aerosol (SOA), such an increase of aromatics could lead to $50% increase of global aromatic SOA production and thereby help to reduce the low bias of simulated organic aerosols over the region in previous modeling studies.

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Blue Ti3+ self-doped TiO2 nanoparticles with mixed phases of anatase and rutile have been synthesized via a facile solvothermal method. The phase evolution of the blue TiO2 varying from anatase to rutile has been studied by simply controlling the initial volume ratios of TiCl3 to titanium isopropoxide in the reaction solutions. The blue TiO2 has a distinct improvement of visible light harvesting and remarkable enhancement in photocatalytic activity, which could be ascribed to the presence of Ti3+ centers and the synergetic effect between the two phases. In addition, the as-prepared blue TiO2 shows an excellent stability during the photocatalytic reactions. A photocatalytic mechanism of the self-doped blue TiO2 was proposed at last.

The structure, metal-insulator transition (MIT), and related Terahertz (THz) transmission characteristics of VO2 thin films obtained by sputtering deposition on c-, r-, and m-plane sapphire substrates were investigated by different techniques. On c-sapphire, monoclinic VO2 films were characterized to be epitaxial films with triple domain structure caused by β-angle mismatch. Monoclinic VO2 β angle of 122.2° and the two angles of V4+–V4+ chain deviating from the am axis of 4.4° and 4.3° are determined. On r-sapphire, tetragonal VO2 was determined to be epitaxially deposited with VO2 (011)T perpendicular to the growth direction, while the structural phase transformation into lower symmetric monoclinic phase results in (2¯11) and (200) orientations forming a twinned structure. VO2 on m-sapphire has several growth orientations, related with the uneven substrate surface and possible inter-diffusion between film and substrate. Measurements of the electrical properties show that the sample on r-sapphire has MIT property superior to the other two samples, with a resistivity change as large as 9 × 104 times and a transition window as narrow as 3.9 K, and it has the highest resistivity with the lowest free carrier density in the insulating phase. THz transmission measurements on VO2 films grown on r-plane sapphire substrates revealed intensity modulation depth as large as 98% over a broadband THz region, suggesting that VO2 films are ideal material candidates for THz modulation applications.