As a diagenetic progress, bioturbation influences solute exchange across the sediment-water interface （SWI）. Different benthic animals have various mechanical activities in sediment, thereby they may have different ...As a diagenetic progress, bioturbation influences solute exchange across the sediment-water interface （SWI）. Different benthic animals have various mechanical activities in sediment, thereby they may have different effects on solute exchange across the SWI. This laboratory study examined the impacts of different benthic animals on phosphorus dynamics across the SWI. Tubificid worms and Chironomidae larvae were introduced as model organisms which, based on their mechanical activities, belong to upward-conveyors and gallery-diffusers, respectively. The microcosm simulation study was carried out with a continuous flow culture system, and all sediment, water, and worms and larvae specimens were sampled from Taihu Lake, China. To compare their bioturbation effects, the same biomass （17.1 g wet weight （ww）/m ^2 ） was adopted for worms and larvae. Worms altered no oxygen penetration depth in sediment, while larvae increased the O 2 penetration depth, compared to the control treatment. Their emergence also enhanced sediment O 2 uptake. The oxidation of ferrous iron in pore water produced ferric iron oxyhydroxides that adsorbed soluble reactive phosphorus （SRP） from the overlying water and pore water. Larvae built obviously oxidized tubes with about 2 mm diameter and the maximum length of 6 cm in sediment, and significantly decreased ferrous iron and SRP in the pore water compared to the control and worms treatments. Worms constructed no visually-oxidized galleries in the sediment in contrast to larvae, and they did not significantly alter SRP in the pore water relative to the control treatment. The adsorption of ferric iron oxyhydroxides to SRP caused by worms and larvae inhibited SRP release from sediment. Comparatively, worms inhibited more SRP release than larvae based on the same biomass, as they successively renewed the ferric iron oxyhydroxides rich oxidation layer through their deposition.展开更多
Chromium and/or arsenate removal by Fe（Ⅱ） as a function of pH, Fe（Ⅱ） dosage and initial Cr（Ⅵ）/As（Ⅴ） ratio were examined in batch tests. The presence of arsenate reduced the removal efficiency of chromium b...Chromium and/or arsenate removal by Fe（Ⅱ） as a function of pH, Fe（Ⅱ） dosage and initial Cr（Ⅵ）/As（Ⅴ） ratio were examined in batch tests. The presence of arsenate reduced the removal efficiency of chromium by Fe（Ⅱ）, while the presence of chromate significantly increased the removal efficiency of arsenate by Fe（Ⅱ） at pH 6-8, In the absence of arsenate, chromium removal by Fe（Ⅱ） increased to a maximum with increasing pH from 4 to 7 and then decreased with a further increase in pH. The increment in Fe（Ⅱ） dosage resulted in an improvement in chromium removal and the improvement was more remarkable under alkaline conditions than that under acidic conditions. Chromium removal by Fe（Ⅱ） was reduced to a larger extent under neutral and alkaline conditions than that under acidic conditions due to the presence of 10 μtmol/L arsenate. The presence of 20 μmol/L arsenate slightly improved chromium removal by Fe（Ⅱ） at pH 3.9-5,8, but had detrimental effects at pH 6.7-9.8. Arsenate removal was improved significantly at pH 4-9 due to the presence of 10μmol/L chromate at Fe（Ⅱ） dosages of 20-60 μmol/L. Elevating the chromate concentration from 10 to 20μmol/L resulted in a further improvement in arsenate removal at pH 4.0-4.6 when Fe（Ⅱ） was dosed at 30-60 μmol/L.展开更多
目的研究青蒿琥酯抗肺腺癌细胞的选择性及其作用机制。方法利用流式细胞仪检测培养的胚肺成纤维细胞和肺腺癌细胞转铁蛋白受体的表达情况,利用四氮唑蓝比色法观察不同浓度青蒿琥酯对培养的两种细胞在应用或不用全铁转运蛋白预处理情况下...目的研究青蒿琥酯抗肺腺癌细胞的选择性及其作用机制。方法利用流式细胞仪检测培养的胚肺成纤维细胞和肺腺癌细胞转铁蛋白受体的表达情况,利用四氮唑蓝比色法观察不同浓度青蒿琥酯对培养的两种细胞在应用或不用全铁转运蛋白预处理情况下48 h的生长抑制情况,并以顺铂作为阳性对照。结果胚肺成纤维细胞表面转铁蛋白受体荧光强度为0.11±0.04,肺腺癌细胞为0.54±0.06;48 h 200μg.ml-1青蒿琥酯对胚肺成纤维细胞的抑制率为(12.56±0.31%),用全铁转运蛋白处理后抑制率为(13.02±0.69)%;对肺腺癌细胞的抑制率为(74.30±0.32)%,用全铁转运蛋白处理后抑制率为(96.12±0.43)%;10μg.ml-1顺铂对胚肺成纤维细胞抑制率为(36.50±0.61)%,对肺腺癌细胞抑制率为(92.65±0.56)%。结论青蒿琥酯对肺腺癌细胞具有选择性细胞毒作用,这与肺腺癌细胞高表达转铁蛋白受体和对铁离子高需求有关。展开更多
基金supported by the National Natural Science Foundation of China(No.40730528,50979102)the Society Development Project of Jiangsu Province(No.BE2009603)
文摘As a diagenetic progress, bioturbation influences solute exchange across the sediment-water interface （SWI）. Different benthic animals have various mechanical activities in sediment, thereby they may have different effects on solute exchange across the SWI. This laboratory study examined the impacts of different benthic animals on phosphorus dynamics across the SWI. Tubificid worms and Chironomidae larvae were introduced as model organisms which, based on their mechanical activities, belong to upward-conveyors and gallery-diffusers, respectively. The microcosm simulation study was carried out with a continuous flow culture system, and all sediment, water, and worms and larvae specimens were sampled from Taihu Lake, China. To compare their bioturbation effects, the same biomass （17.1 g wet weight （ww）/m ^2 ） was adopted for worms and larvae. Worms altered no oxygen penetration depth in sediment, while larvae increased the O 2 penetration depth, compared to the control treatment. Their emergence also enhanced sediment O 2 uptake. The oxidation of ferrous iron in pore water produced ferric iron oxyhydroxides that adsorbed soluble reactive phosphorus （SRP） from the overlying water and pore water. Larvae built obviously oxidized tubes with about 2 mm diameter and the maximum length of 6 cm in sediment, and significantly decreased ferrous iron and SRP in the pore water compared to the control and worms treatments. Worms constructed no visually-oxidized galleries in the sediment in contrast to larvae, and they did not significantly alter SRP in the pore water relative to the control treatment. The adsorption of ferric iron oxyhydroxides to SRP caused by worms and larvae inhibited SRP release from sediment. Comparatively, worms inhibited more SRP release than larvae based on the same biomass, as they successively renewed the ferric iron oxyhydroxides rich oxidation layer through their deposition.
基金supported by the National Natural Science Foundation of China (No. 50908060,50821002)the Ph.D Program Foundation of Ministry of Education of China for New Faculty (No. 200802131053)
文摘Chromium and/or arsenate removal by Fe（Ⅱ） as a function of pH, Fe（Ⅱ） dosage and initial Cr（Ⅵ）/As（Ⅴ） ratio were examined in batch tests. The presence of arsenate reduced the removal efficiency of chromium by Fe（Ⅱ）, while the presence of chromate significantly increased the removal efficiency of arsenate by Fe（Ⅱ） at pH 6-8, In the absence of arsenate, chromium removal by Fe（Ⅱ） increased to a maximum with increasing pH from 4 to 7 and then decreased with a further increase in pH. The increment in Fe（Ⅱ） dosage resulted in an improvement in chromium removal and the improvement was more remarkable under alkaline conditions than that under acidic conditions. Chromium removal by Fe（Ⅱ） was reduced to a larger extent under neutral and alkaline conditions than that under acidic conditions due to the presence of 10 μtmol/L arsenate. The presence of 20 μmol/L arsenate slightly improved chromium removal by Fe（Ⅱ） at pH 3.9-5,8, but had detrimental effects at pH 6.7-9.8. Arsenate removal was improved significantly at pH 4-9 due to the presence of 10μmol/L chromate at Fe（Ⅱ） dosages of 20-60 μmol/L. Elevating the chromate concentration from 10 to 20μmol/L resulted in a further improvement in arsenate removal at pH 4.0-4.6 when Fe（Ⅱ） was dosed at 30-60 μmol/L.
文摘目的研究青蒿琥酯抗肺腺癌细胞的选择性及其作用机制。方法利用流式细胞仪检测培养的胚肺成纤维细胞和肺腺癌细胞转铁蛋白受体的表达情况,利用四氮唑蓝比色法观察不同浓度青蒿琥酯对培养的两种细胞在应用或不用全铁转运蛋白预处理情况下48 h的生长抑制情况,并以顺铂作为阳性对照。结果胚肺成纤维细胞表面转铁蛋白受体荧光强度为0.11±0.04,肺腺癌细胞为0.54±0.06;48 h 200μg.ml-1青蒿琥酯对胚肺成纤维细胞的抑制率为(12.56±0.31%),用全铁转运蛋白处理后抑制率为(13.02±0.69)%;对肺腺癌细胞的抑制率为(74.30±0.32)%,用全铁转运蛋白处理后抑制率为(96.12±0.43)%;10μg.ml-1顺铂对胚肺成纤维细胞抑制率为(36.50±0.61)%,对肺腺癌细胞抑制率为(92.65±0.56)%。结论青蒿琥酯对肺腺癌细胞具有选择性细胞毒作用,这与肺腺癌细胞高表达转铁蛋白受体和对铁离子高需求有关。
