22 research outputs found

    Selective and Continuous Electrosynthesis of Hydrogen Peroxide on Nitrogen-doped Carbon Supported Nickel

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    Hydrogen peroxide is a widely used industrial oxidant, the large-scale production of which continues to be done by an indirect process. Direct electrosynthesis of hydrogen peroxide from aerial oxygen and water is a sustainable alternative, but this remains challenging because hydrogen peroxide is highly reactive and robust catalysts are vital. Here, we report direct and continuous electrosynthesis of hydrogen peroxide under alkaline conditions using a nitrogen-doped-carbon-supported nickel catalyst. Both experiment and theoretical calculations confirm that the existence of nickel particles suppresses the further reduction of hydrogen peroxide on Ni-N-C matrix. In air-saturated 0.1 M potassium hydroxide, the energy-efficient non-precious metal electrocatalyst exhibits a consistent Faraday efficiency over 95% at a steady rate of hydrogen peroxide production (15.1 mmol mināˆ’1 gcatāˆ’1) for 100 h. This sustainable, efficient, and safe process is an important step toward continuous production of hydrogen peroxide

    The oyster genome reveals stress adaptation and complexity of shell formation

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    The Pacific oyster Crassostrea gigas belongs to one of the most species-rich but genomically poorly explored phyla, the Mollusca. Here we report the sequencing and assembly of the oyster genome using short reads and a fosmid-pooling strategy, along with transcriptomes of development and stress response and the proteome of the shell. The oyster genome is highly polymorphic and rich in repetitive sequences, with some transposable elements still actively shaping variation. Transcriptome studies reveal an extensive set of genes responding to environmental stress. The expansion of genes coding for heat shock protein 70 and inhibitors of apoptosis is probably central to the oyster's adaptation to sessile life in the highly stressful intertidal zone. Our analyses also show that shell formation in molluscs is more complex than currently understood and involves extensive participation of cells and their exosomes. The oyster genome sequence fills a void in our understanding of the Lophotrochozoa. Ā© 2012 Macmillan Publishers Limited. All rights reserved

    Geochemistry and Holocene Sedimentary Environment Evolution of Subaqueous Clinoform off Shandong Peninsula (Yellow Sea)

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    As a key sedimentary body connecting the north and South Yellow Sea, the subaqueous clinoform off Shandong Peninsula plays an important role in the sedimentary system of China seas, and it is also a studied example in the study among the major ā€œsource to sinkā€ systems. Based on AMS 14C dating, sediment grain size, major and trace element contents from core WH-05 located at the edge of the clinoform, we discuss changes in the deposition rate, analyze sediment provenance and controlling factors, and reveal the environmental evolution of the source area since the Holocene. Results from core WH-05 show that marine sedimentation began at about 8.5 ka B.P. The deposition rate decreased from the initial 28.37 m/ka to 0.52 m/ka. Sediment provenance suggests that the Huanghe river sediments have been the main source for the study area since the Holocene. The As/Al, V/Sc indicators show that the environmental oxidation environment was gradually weakened and then increased slightly starting from 7.0 ka B.P. The change in redox is consistent with the change in sea level, the deposition rate, and depositional depth

    Geochemistry and Holocene Sedimentary Environment Evolution of Subaqueous Clinoform off Shandong Peninsula (Yellow Sea)

    No full text
    As a key sedimentary body connecting the north and South Yellow Sea, the subaqueous clinoform off Shandong Peninsula plays an important role in the sedimentary system of China seas, and it is also a studied example in the study among the major ā€œsource to sinkā€ systems. Based on AMS 14C dating, sediment grain size, major and trace element contents from core WH-05 located at the edge of the clinoform, we discuss changes in the deposition rate, analyze sediment provenance and controlling factors, and reveal the environmental evolution of the source area since the Holocene. Results from core WH-05 show that marine sedimentation began at about 8.5 ka B.P. The deposition rate decreased from the initial 28.37 m/ka to 0.52 m/ka. Sediment provenance suggests that the Huanghe river sediments have been the main source for the study area since the Holocene. The As/Al, V/Sc indicators show that the environmental oxidation environment was gradually weakened and then increased slightly starting from 7.0 ka B.P. The change in redox is consistent with the change in sea level, the deposition rate, and depositional depth

    Association of Physical Activity and Sedentary Behaviors with the Risk of Refractive Error in Chinese Urban/Rural Boys and Girls

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    Background: Research shows physical activity (PA) is negatively associated with refractive error, especially outdoor activity. Our study aimed to examine the association of PA levels and sedentary time (SED) with refractive error in boys and girls living in urban and rural areas. Methods: A total of 8506 urban/rural boys and girls (13.5 Ā± 2.8 years old) in Shaanxi Province, China participated in this study. Questions about PA, SED, outdoor exercises, and digital screen time were asked in the study survey. Non-cycloplegic refractive error was measured by an autorefractor. The differences between sex/area groups have been analyzed by one-way ANOVA. The association of PA/SED with spherical equivalent (SE) and cylinder power was analyzed by general linear regression. The association between PA/SED and the risk of refractive error was determined using the binary logistic regression model. Results: Of the 8506 participants, the prevalence of refractive error was significantly higher in girls and urban students (p p p p < 0.05). Conclusions: PA and SED were associated with the risk of refractive error. Maintaining a healthy lifestyle can help to reduce the risk of refractive error in boys and girls

    Association of Physical Activity and Sedentary Behaviors with the Risk of Refractive Error in Chinese Urban/Rural Boys and Girls

    No full text
    Background: Research shows physical activity (PA) is negatively associated with refractive error, especially outdoor activity. Our study aimed to examine the association of PA levels and sedentary time (SED) with refractive error in boys and girls living in urban and rural areas. Methods: A total of 8506 urban/rural boys and girls (13.5 &plusmn; 2.8 years old) in Shaanxi Province, China participated in this study. Questions about PA, SED, outdoor exercises, and digital screen time were asked in the study survey. Non-cycloplegic refractive error was measured by an autorefractor. The differences between sex/area groups have been analyzed by one-way ANOVA. The association of PA/SED with spherical equivalent (SE) and cylinder power was analyzed by general linear regression. The association between PA/SED and the risk of refractive error was determined using the binary logistic regression model. Results: Of the 8506 participants, the prevalence of refractive error was significantly higher in girls and urban students (p &lt; 0.05). Less SED and digital screen time, and more outdoor activity were significantly associated with SE (p &lt; 0.05), respectively. More PA and less SED were significantly associated with lower cylinder power (p &lt; 0.05), respectively. More PA and less SED were significantly associated with lower risks of myopia and astigmatism, respectively (p &lt; 0.05). Conclusions: PA and SED were associated with the risk of refractive error. Maintaining a healthy lifestyle can help to reduce the risk of refractive error in boys and girls
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