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In recent years, with the deepening research, metal zinc oxide (ZnO) nanomaterials have become a popular research object in the biological field, particularly in biomedicine and food safety, which is attributed to their unique physicochemical properties such as high surface area and volume ratio, luminescence effect, surface characteristics and biological activities. Herein, this review provides a detailed overview of the ZnO nanomaterial-mediated biological applications that involve anti-bacterial, anti-tumor, anti-inflammation, skin care, biological imaging and food packaging applications. Importantly, the corresponding action mechanisms of ZnO nanomaterials are pointed. Additionally, the structure and structure-dependent physicochemical properties, the common synthesis methods and the biosafety of ZnO nanoparticles are revealed in brief. Finally, the significance and future challenges of ZnO nanomaterial applications are concluded.

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We carry out a comprehensive temperature-dependent photoluminescence (PL) study on chemically derived graphene oxide (GO) sheets. According to the unusual temperature dependence, we introduce a trap state $114 meV beneath the LUMO, which implies an additional carrier decay process.Graphene oxide (GO), as a chemical derivative of graphene, has raised intense interest from physics to chemistry. 1 GO derives many excellent properties from graphene, and provides an alternative to exible substrates, 2 Langmuir-Blodgett lms, 3 chemical sensors, 4 transparent electrodes, 5 etc. Luminous carbon nanomaterials, 6 considered as an alternative for conventional uorescent quantum dots, 7 have been highlighted due to their high bio-compatibility in favor of the applications in biology and medicine. 8 GO, as a counterpart of carbon related materials, also has interesting photoluminescence (PL) features 9 and has been employed in LED 10 and lithography. 11 Recently, PL from GO has been developed in ultraviolet (UV) and visible light range by several groups. 12-15 A summary of PL from GO fabricated by various methods can be found in a recent review article. 16 However, the origin of luminescence from GO is controversial so far. 9,13,14,[17][18][19][20] Chhowalla 13 considers that sp 2 clusters isolated by sp 3 matrix in GO planes are likely responsible for the blue luminescence. Electron-hole recombination from the bottom of the conduction band and nearby localized states to wide-range valance band is suggested as origin of the PL in GO in the view of atomic structure. 17 Galande et al. 18 proposed that PL in GO arises from quasi-molecular uorophores. Free zigzag sites with carbene-like triplet ground states are also theoretically anticipated 19 and experimentally conrmed 20 as a candidate for photon emission from

Long-term cover cropping seasonally affects soil microbial carbon metabolism in an apple orchard, Bioengineered, 10:1, 207-217, ABSTRACT Groundcover management can significantly affect soil microbial metabolic activities, especially carbon metabolism, in apple orchards. However, there have been few studies on the effects of groundcover on the seasonality of soil microbial carbon metabolism. We, therefore, studied soil microbial carbon metabolism in an apple orchard on China's Loess Plateau under four single species cover crops (the grass Dactylis glomerata L., and the legumes Trifolium repens, Coronilla varia L., Lotus corniculatus L.) during spring, summer and fall. Cover cropping significantly, but differentially, promoted soil microbial carbon metabolism in spring and fall. However, cover cropping leads to a significant reduction of soil moisture in spring and summer due to the competition of soil moisture between the cover crops and apple trees, which probably lead to the changes in types of carbon substances metabolizing by soil microbes in summer. Besides, cover crop significantly enhanced soil organic carbon contents between three seasons while clean cultivation had slight, non-significant effects. The promotion of soil microbial metabolic activities was probably an important mechanism for the carbon accumulation, and we postulate that leguminous cover plants may have significantly different effects, mediated through their root exudates, from grasses on soil carbon contents. ARTICLE HISTORY