Semiconductor-mediated photocatalysis has received tremendous attention as it holds great promise to address the worldwide energy and environmental issues. To overcome the serious drawbacks of fast charge recombination and the limited visible-light absorption of semiconductor photocatalysts, many strategies have been developed in the past few decades and the most widely used one is to develop photocatalytic heterojunctions. This review attempts to summarize the recent progress in the rational design and fabrication of heterojunction photocatalysts, such as the semiconductor-semiconductor heterojunction, the semiconductor-metal heterojunction, the semiconductor-carbon heterojunction and the multicomponent heterojunction. The photocatalytic properties of the four junction systems are also discussed in relation to the environmental and energy applications, such as degradation of pollutants, hydrogen generation and photocatalytic disinfection. This tutorial review ends with a summary and some perspectives on the challenges and new directions in this exciting and still emerging area of research.

A new photothermal coupling agent for photothermal ablation (PTA) therapy of tumors is developed based on ultrathin PEGylated W18O49 nanowires. After being injected with the nanowire solution, the in vivo tumors exhibit a rapid temperature rise to 50.0 ± 0.5 °C upon irradiation with NIR laser light at a safe, low intensity (0.72 W cm(-2)) for 2 min (left-hand mouse in the figure),), resulting in the efficient PTA of cancer cells in vivo in 10 min.

ObjectiveCurrent evidence suggests high serum uric acid may increase the risk of type 2 diabetes, but the association is still uncertain. The aim of the study was to evaluate the association between serum uric acid and future risk of type 2 diabetes by conducting a meta-analysis of prospective cohort studies.Design and MethodsWe conducted a systematic literature search of the PubMed database through April 2012. Prospective cohort studies were included in meta-analysis that reported the multivariate adjusted relative risks (RRs) and the corresponding 95% confidence intervals (CIs) for the association between serum uric acid and risk of type 2 diabetes. We used both fix-effects and random-effects models to calculate the overall effect estimate. The heterogeneity across studies was tested by both Q statistic and I2 statistic. Begg’s funnel plot and Egger’s regression test were used to assess the potential publication bias.ResultsWe retrieved 7 eligible articles derived from 8 prospective cohort studies, involving a total of 32016 participants and 2930 incident type 2 diabetes. The combined RR of developing type 2 diabetes for the highest category of serum uric acid level compared with the lowest was 1.56(95% CI, 1.39–1.76). Dose-response analysis showed the risk of type 2 diabetes was increased by 6% per 1 mg/dl increment in serum uric acid level (RR 1.06, 95% CI: 1.04–1.07). The result from each subgroup showed a significant association between serum uric acid and risk of type 2 diabetes. In sensitive analysis, the combined RR was consistent every time omitting any one study. Little evidence of heterogeneity and publication bias was observed.ConclusionsOur meta-analysis of prospective cohort studies provided strong evidence that high level of serum uric acid is independent of other established risk factors, especially metabolic syndrome components, for developing type 2 diabetes in middle-aged and older people.

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Many studies have shown the effect of solution chemistry on the environmental behavior of metal-based nanoparticles (NPs), except CuO NPs. Here, we investigated the agglomeration, sedimentation, dissolution, and speciation of CuO NPs by varying pH, ionic strength, ionic valence, and natural organic matter (NOM). The results showed that as the pH moved away from 6, the size of CuO agglomerates decreased, along with the enhanced NP suspension stabilization, due to the increase of electrostatic repulsive force. Increasing ionic strength and valence intensified the agglomeration and sedimentation of CuO NPs because of the compression of electrical double layers. The presence of humic acid and citric acid enhanced the dispersion and stabilization of CuO NP suspension, but l-cysteine showed a different impact. Decreasing pH, increasing ionic strength and all NOM improved the dissolution of CuO NPs, but the divalent electrolyte (CaCl2) inhibited the Cu2+ release from CuO NPs compared to the monovalent electrolyte (NaCl). In addition, X-ray absorption near edge structure (XANES) analysis demonstrated that the presence of l-cysteine transformed more than 30% of CuO NPs to Cu(I)-cysteine by coordinating with thiol group. This study can give us an in-depth understanding on the environmental behavior and fate of CuO NPs in the aquatic environment.