29 research outputs found

    Unique allosteric effect driven rapid adsorption of carbon dioxide on a new ionogel [P4444][2-Op]@MCM-41 with excellent cyclic stability and loading-dependent capacity

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    Allosteric effect-driven rapid stepwise CO2 adsorption of pyridine-containing anion functionalized ionic liquid [P4444][2-Op] confined into mesoporous silica MCM-41.</p

    Recent advances in spatio-temporal distribution of endogenous phytohormones

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    Higher Heat Stress Increases the Negative Impact on Rice Production in South China: A New Perspective on Agricultural Weather Index Insurance

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    Rice is a major staple food grain for more than half of the world’s population, and China is the largest rice producer and consumer in the world. In a climate-warming context, the frequency, duration and intensity of heat waves tend to increase, and rice production will be exposed to higher heat damage risks. Understanding the negative impacts of climate change on the rice supply is a critical issue. In this study, a new perspective on agricultural weather index insurance is proposed to investigate the impact of extreme high-temperature events on rice production in South China in the context of climate change. Based on data from meteorological stations in Anhui Province in China from 1961 to 2018 and the projected data from five Global Climate Models under three representative concentration pathway (RCP) scenarios from 2021 to 2099, the spatial–temporal characteristics of heat stress and its influence on rice production were analyzed by employing a weather index insurance model. The interdecadal breakpoints in the trends of the heat stress weather insurance index (HSWI) and the payout from 1961 to 2018 in 1987 were both determined, which are consistent with the more significant global warming since the 1980s. The largest increase after 1987 was found in the southeastern part of the study area. The projected HSWI and the payout increased significantly from 2021 to 2099, and their growth was faster with higher radiative forcing levels. The HSWI values were on average 1.4 times, 3.3 times and 6.1 times higher and the payouts were on average 3.9 times, 9.8 times and 15.0 times higher than the reference values for the near future, mid-future and far future, respectively. The results suggest that a more severe influence of heat damage on rice production will probably happen in the future, and it is vital to develop relevant adaptation strategies for the effects of a warmer climate and heat stress on rice production. This paper provides an alternative way to transform the evaluation of the extreme climate event index into the quantitative estimation of disaster impacts on crop production

    Evaluation and Parameter Optimization of Monthly Net Long-Wave Radiation Climatology Methods in China

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    Based on surface radiation balance data and meteorological observations at 19 radiation stations in China from 1993 to 2012, we assessed the applicability of seven empirical formulas for the estimation of monthly surface net long-wave radiation (Rnl). We then established a revised method applicable to China by re-fitting the formula using new observational data. The iterative solution method and the multivariate regression analysis method with the minimum root mean square error (RMSE) were used as the objective functions in the revised method. Meanwhile, the accuracy of the CERES (Clouds and the Earth’s Radiant Energy System) estimated Rnl was also evaluated. Results show that monthly Rnl over China was underestimated by the seven formulas and the CERES data. The Tong Hongliang formula with lowest errors was the best among the seven formulas for estimating Rnl over China as a whole, followed by the Penman and the Deng Genyun formulas. The estimated Rnl based on the CERES data also showed relatively higher precision in accordance with the three formulas mentioned above. The FAO56-PM formula (Penman–Monteith formula recommended in the No. 56 report of the Food and Agriculture Organization) without calibration was not applicable to China due to its low accuracy. For individual stations, the Deng Genyun formula was the most accurate in the eastern plain area, while the Tong Hongliang formula was suitable for the plateau. Regional formulas were established based on the geographical distribution of water vapor pressure and elevation over China. The revised national and regional formulas were more accurate than the seven original formulas and the CERES data. Furthermore, the regional formulas produced smaller errors than the national formula at most of the stations. The regional formulas were clearly more accurate than the Deng Genyun formula at stations in Northwestern China and on the Tibetan Plateau. They were also more accurate than the Tong Hongliang formula at the stations located in the eastern area. Therefore, the regional formulas developed in this study are recommended as the standard climatology formulas to calculate monthly Rnl over China

    Reducing liver cancer risk beginning at birth: experiences of preventing chronic hepatitis B virus infection in China

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    In China, the death numbers due to primary liver cancer every year account for more than half of this disease burden worldwide. Hepatocellular carcinoma (HCC) represents the major histological type of primary liver cancer. In the Chinese population, at least 85% HCC cases are due to chronic infection with hepatitis B virus (HBV), most of which were acquired in the perinatal period or in early life. As of January 1992, HBV immunization of newborns was introduced to the national Expended Program of Immunization of China. Prior to this program, the Qidong County in China conducted an hepatitis B intervention study, which was a population-based, cluster randomized, controlled trial of HBV vaccination in neonates. The study demonstrated that among young adults &lt; 30 years old, neonatal HBV immunization decreased around 84% risk of HBV-related liver cancer, and 70% risk of mortality due to severe end-stage chronic liver diseases. More than 72% efficacy of neonatal vaccination against chronic HBV infection in adulthood was achieved; however, when catch-up HBV vaccination was given to children at age 10-14 years, the protection efficacy was only 21%. No difference in mortality of HBV-related liver diseases was observed among the young adults &lt; 30 years who received and those who did not receive the catch-up HBV vaccination. These results highlight the crucial importance of HBV vaccination of neonates in reducing the liver cancer risk beginning at birth in highly HBV endemic regions. Due to large numbers of HBV-infected pregnant women with high viremia in China, clinical studies in which antiviral therapy with the nucleot(s)ide analogues was given to HBV-infected pregnant women have provided important evidence that such therapy can reduce the risk of mother-to-child HBV transmission. These clinical data based on cohort studies, randomized clinical trials, and clinical practices in the Chinese population provide important information on prevention of liver cancer, particularly HCC, by preventing chronic HBV infection starting from birth for other populations

    One-step preparation of zirconia coated silica microspheres and modification with D-fructose 1, 6-bisphosphate as stationary phase for hydrophilic interaction chromatography

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    In this study, ZrO2 layer coated silica microspheres (ZrO2/SiO2) were successfully prepared by a facile one-step surfactant-free hydrothermal route under low pH condition. The synthesized ZrO2/SiO2 material was then modified with D-fructose 1, 6-bisphosphate (FDP) to improve the chromatographic separation property of the material. Fused-silica capillary columns were prepared with the modified material for evaluation. Phenolic, nucleobases and alkaloids compounds in hydrophilic interaction chromatographic (HILIC) mode showed symmetrical peaks. The FDP-ZrO2/SiO2 stationary phase showed better performance than ZrO2/SiO2 packing material and demonstrated great potential for application in HILIC mode. (C) 2017 Elsevier B.V. All rights reserved

    Surface Modification of Nano-TiO 2

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    Research on Oil and Gas Pipeline Operation Optimization Based on Improved Newton-Raphson Method

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    Oil and gas pipelines are the main channel to ensure national energy security and national economic development due to the safety and efficiency of the transportation coast. To achieve an optimal state of pipeline operation in terms of safety and efficiency is the crucial important issue throughout the life cycle of a pipeline system. However, the optimization problem of the pipeline network system is a typical Mixed Integer Non-Linear Problem (MINLP) which are extremely difficult to solve. An optimal solution to keep pipeline operated in most efficient state under the premise of safe operation is given in the paper by using the dynamical programming method. Firstly, the improved Newton-Raphson method is used to solve the discrete pipeline system, and the operating parameters such as temperature, pressure and flow of any section surface in the pipeline are obtained. The fluid parameter values of the each discrete nodes can ensure the safety of the pipeline. Based on this, the total energy consumption cost is set as the objective function, and the oil and gas pipeline operation optimization model is then established, and the dynamic programming method is used to solve it, so that it can obtain the optimal solution of the current working conditions in a reasonable computational cost. The actual example shows that the energy cost of the optimized operation scheme can be reduced by 6.8% compared with the pre-optimization scheme

    Dispersive Matrix Solid-Phase Extraction Method Coupled with High Performance Liquid Chromatography-Tandem Mass Spectrometry for Ultrasensitive Quantification of Endogenous Brassinosteroids in Minute Plants and Its Application for Geographical Distribution, Study

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    An ultrasensitive analysis method for quantification of endogenous brassinosteroids in fresh minute plants was developed based on dispersive matrix solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry. During the dispersive matrix solid-phase extraction, plant samples were first ground with solid sorbent (dispersant) in one microcentrifuge tube and then centrifuged after adding extraction solvent and cleanup materials (another type of sorbent). Three protocols based on dispersive matrix solid-phase extraction were compared and discussed for plant samples with different matrix complexity. The choice of any protocol was a compromise of increasing purification efficiency and decreasing sample loss. Under optimized conditions, the limits of detection were 1.38-6.75 pg mL(-1) for five brassinosteroids in the oilseed rape samples. The intraday and interday precisions were in the range of 0.8%-9.8% and 4.6%-17.3%, respectively. The proposed method was successfully applied to detection of endogenous brassinosteroids in milligram oilseed rape (2.0 mg) and submilligram Arabidopsis thaliana seedlings (0.5 mg). Finally, the geographical distribution of five endogenous brassinosteroids of Brassica napus L. oilseed rape in different provinces of origin in the Yangtze River basin was described

    One step rapid dispersive liquid-liquid micro-extraction with in-situ derivatization for determination of aflatoxins in vegetable oils based on high performance liquid chromatography fluorescence detection

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    A rapid dispersive liquid-liquid micro-extraction (DLLME) with in-situ derivatization method for extraction and purification of aflatoxins (AFs) in vegetable oils was developed and evaluated. Oil extract, dichloromethane and trifluoroacetic acid were mixed and injected into water to form a cloudy solution. AFs in the oil were extracted into the numerous liquid droplets (with diameters from a few microns to dozens of microns) of extractant, where derivatization was carried out in situ. The proposed sample preparation method was coupled with high performance liquid chromatography with fluorescence detection (HPLC-FLD) for determination of four AFs in vegetable oils. The method showed excellent linearity in three orders of magnitude, good relative recoveries, good repeatability and high sensitivity with limits of detection in range of 0.005-0.03 ng/mL. The accuracy of the method was also verified by certified reference sample. Finally, different kinds of vegetable oils from the local supermarket were analyzed
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