In controlling eutrophication phenomenon, there were conventional methods which lead to negative effects to aquatic environment. This study was aimed to investigate the usage of synthesized thiourea compounds to inhib...In controlling eutrophication phenomenon, there were conventional methods which lead to negative effects to aquatic environment. This study was aimed to investigate the usage of synthesized thiourea compounds to inhibit the growth of Oscillatoria sp. in Kenyir lake, Terengganu, Malaysia. The inhibition effects of four eco-friendly alkoxyl thiourea derivatives compounds named as N-（（4-（decyloxy）phenyl）carbamothioyl）-4-methyl benzamide, N-（（4-（decyloxy）phenyl）carbamothioyl）-4-nitro benzamide, 4-chloro-N-（（4-（decyloxy）phenyl）carbamothioyl） benzamide and N-（（4-（decyloxy）phenyl）carbamothioyl） benzamide were examined onto the growth culture of Oscillatoria sp. These compounds were tested in 30 mL of Oscillatoria sp. cultures with different concentration of 16 μg·mL-1, 18 μg·mL-1, 20 μg·mL-1, 24 μg·mL-1 and 28 μg·mL-1respectively. The treatment flasks were supplied with an aerator for 24 hours under continuous illumination at 25 ℃. Chlorophyll-a concentration were extracted to calculate the inhibition percentage of each treatment. Overall, all these compounds showed inhibition effects towards the growth of Oscillatoria sp., with the highest inhibition of 37% by N-（（4-（decyloxy）phenyl）carbamothioyl）-4-methyl benzamide at the concentration of 18μg·mL-1. The methyl group that attach to the synthesized compound may contribute to the effectiveness of the compound which act as an algae inhibitor. However, extensive studies still need to be conducted in order to investigate the mechanism on how this compound reacts with Oscillatoria sp..展开更多
Toxicities （-1gEC50） of 16 phenolic compounds against Q67 were determined, and structural parameters as well as thermodynamic parameters of these compounds were obtained through fully optimized calculations by using...Toxicities （-1gEC50） of 16 phenolic compounds against Q67 were determined, and structural parameters as well as thermodynamic parameters of these compounds were obtained through fully optimized calculations by using B3LYP method of density functional theory （DFT） at the 6-311G^＊＊ level. Moreover, a 3-parameter （molecular average polarizability （α）, heat energy corrected value （Eth） and the most positive hydrogen atomic charge （qH^＋）） correlation model with R^2 = 0.981 and q^2 = 0.967 to predict -1gEC50 was obtained from experimental data based on the above-mentioned parameters as theoretical descriptors. Therein a was the most significant on -1gEC50. Variance Inflation Factors （VIF）, t-value and cross-validation were applied to verify the model, confirming that the resultant model has fairly better stability and predictive ability to predict -1gEC50 of similar compounds.展开更多
在高水平对外开放的背景下,全球价值链地位成为关注焦点。卫生与植物卫生检疫措施(Sanitary and Phytosanitary Measures,简称SPS措施)是影响农业进出口的重要因素,也是发展中国家农产品出口的主要障碍,对农业全球价值链地位有重要影响...在高水平对外开放的背景下,全球价值链地位成为关注焦点。卫生与植物卫生检疫措施(Sanitary and Phytosanitary Measures,简称SPS措施)是影响农业进出口的重要因素,也是发展中国家农产品出口的主要障碍,对农业全球价值链地位有重要影响。在分析SPS措施对农业全球价值链地位影响机理的基础上,本研究基于1995—2018年44个主要经济体国家的面板数据,使用面板固定效应模型检验SPS措施对农业全球价值链地位的直接影响和间接影响及其实现机制。研究结果表明:1)SPS措施能够直接提升发起国的农业全球价值链地位;2)SPS措施通过影响技术水平间接提升发起国的全球价值链地位;3)农业部门技术水平与农业全球价值链地位之间是非线性关系,且技术水平提高发起国的农业全球价值链地位具有单门限,只有超过门限值后技术水平才会明显提升发起国农业全球价值链地位;4)SPS措施对发展中国家农业全球价值链地位的提升作用虽不及发达国家显著,但仍有提升效果。因此在推动中国高水平对外开放的过程中,可以科学合理运用SPS措施提高中国的农业全球价值链地位,提升中国农业部门技术水平,促进农业部门高质量发展。展开更多
Shang Xun, Dai Jixun, Han Baoqin, Ru Binggen, Zhou Xianwan ( Marine Life Sciences College, Ocean University of Qingdao, Qingdao 266003 College of Life and Sciences, Peking University,Beijing 100871)
文摘In controlling eutrophication phenomenon, there were conventional methods which lead to negative effects to aquatic environment. This study was aimed to investigate the usage of synthesized thiourea compounds to inhibit the growth of Oscillatoria sp. in Kenyir lake, Terengganu, Malaysia. The inhibition effects of four eco-friendly alkoxyl thiourea derivatives compounds named as N-（（4-（decyloxy）phenyl）carbamothioyl）-4-methyl benzamide, N-（（4-（decyloxy）phenyl）carbamothioyl）-4-nitro benzamide, 4-chloro-N-（（4-（decyloxy）phenyl）carbamothioyl） benzamide and N-（（4-（decyloxy）phenyl）carbamothioyl） benzamide were examined onto the growth culture of Oscillatoria sp. These compounds were tested in 30 mL of Oscillatoria sp. cultures with different concentration of 16 μg·mL-1, 18 μg·mL-1, 20 μg·mL-1, 24 μg·mL-1 and 28 μg·mL-1respectively. The treatment flasks were supplied with an aerator for 24 hours under continuous illumination at 25 ℃. Chlorophyll-a concentration were extracted to calculate the inhibition percentage of each treatment. Overall, all these compounds showed inhibition effects towards the growth of Oscillatoria sp., with the highest inhibition of 37% by N-（（4-（decyloxy）phenyl）carbamothioyl）-4-methyl benzamide at the concentration of 18μg·mL-1. The methyl group that attach to the synthesized compound may contribute to the effectiveness of the compound which act as an algae inhibitor. However, extensive studies still need to be conducted in order to investigate the mechanism on how this compound reacts with Oscillatoria sp..
基金supported by the Natural Science Foundation of Zhejiang Province (No. 2008Y507280)
文摘Toxicities （-1gEC50） of 16 phenolic compounds against Q67 were determined, and structural parameters as well as thermodynamic parameters of these compounds were obtained through fully optimized calculations by using B3LYP method of density functional theory （DFT） at the 6-311G^＊＊ level. Moreover, a 3-parameter （molecular average polarizability （α）, heat energy corrected value （Eth） and the most positive hydrogen atomic charge （qH^＋）） correlation model with R^2 = 0.981 and q^2 = 0.967 to predict -1gEC50 was obtained from experimental data based on the above-mentioned parameters as theoretical descriptors. Therein a was the most significant on -1gEC50. Variance Inflation Factors （VIF）, t-value and cross-validation were applied to verify the model, confirming that the resultant model has fairly better stability and predictive ability to predict -1gEC50 of similar compounds.
文摘在高水平对外开放的背景下,全球价值链地位成为关注焦点。卫生与植物卫生检疫措施(Sanitary and Phytosanitary Measures,简称SPS措施)是影响农业进出口的重要因素,也是发展中国家农产品出口的主要障碍,对农业全球价值链地位有重要影响。在分析SPS措施对农业全球价值链地位影响机理的基础上,本研究基于1995—2018年44个主要经济体国家的面板数据,使用面板固定效应模型检验SPS措施对农业全球价值链地位的直接影响和间接影响及其实现机制。研究结果表明:1)SPS措施能够直接提升发起国的农业全球价值链地位;2)SPS措施通过影响技术水平间接提升发起国的全球价值链地位;3)农业部门技术水平与农业全球价值链地位之间是非线性关系,且技术水平提高发起国的农业全球价值链地位具有单门限,只有超过门限值后技术水平才会明显提升发起国农业全球价值链地位;4)SPS措施对发展中国家农业全球价值链地位的提升作用虽不及发达国家显著,但仍有提升效果。因此在推动中国高水平对外开放的过程中,可以科学合理运用SPS措施提高中国的农业全球价值链地位,提升中国农业部门技术水平,促进农业部门高质量发展。
文摘Shang Xun, Dai Jixun, Han Baoqin, Ru Binggen, Zhou Xianwan ( Marine Life Sciences College, Ocean University of Qingdao, Qingdao 266003 College of Life and Sciences, Peking University,Beijing 100871)
