The failure of the 2017 Xinmo catastrophic rockslide in Maoxian County, Sichuan, Southwest China was a combined effect of long-term and shortterm triggering factors. Field investigation, historical data collection, la...The failure of the 2017 Xinmo catastrophic rockslide in Maoxian County, Sichuan, Southwest China was a combined effect of long-term and shortterm triggering factors. Field investigation, historical data collection, laboratory tests, chemical and microstructure analysis and numerical simulations were adopted herein to reveal the initiation and failure mechanism of the Xinmo rockslide. The analytical results showed that this failure involved the coupling of several triggering factors. The initial cracks in the rock mass were induced by historical earthquakes due to the convex topography and the direction effect. Rock masses from the source area of the Xinmo rockslide contain water-sensitive minerals, i.e., albite and chamosite, and the easily oxidized chemical element Fe, resulting in obvious strength deterioration under the action of water. The scanning electron microscopy(SEM) experimental results indicated that the internal structure of the rock mass is conducive to weathering. The compressive and shear strengths of the rock mass were reduced due to freeze-thaw cycles and weathering. The antecedent rainfall further deteriorated the stability of the slope, and stress and deformation accumulated continually in the locked section. Finally, the locked section sheared out, and the slope failed. An entrainment effect was observed in the Xinmo rockslide due to the presence of old landslide deposits and the antecedent rainfall, resulting in an amplification of the catastrophic rockslide. A simplified three dimensional analysis model was established in this study to reveal the influence of the triggering factors on the failure mechanism of the Xinmo rockslide.展开更多
The acute effect of acupuncture on Alzheimer＇s disease,i.e.,on brain activation during treatment,has been reported.However,the effect of long-term acupuncture on brain activation in Alzheimer＇s disease is unclear.Th...The acute effect of acupuncture on Alzheimer＇s disease,i.e.,on brain activation during treatment,has been reported.However,the effect of long-term acupuncture on brain activation in Alzheimer＇s disease is unclear.Therefore,in this study,we performed long-term needling at Zusanli（ST36）or a sham point（1.5 mm lateral to ST36）in a rat Alzheimer＇s disease model,for 30 minutes,once per day,for 30 days.The rats underwent 18F-fluorodeoxyglucose positron emission tomography scanning.Positron emission tomography images were processed with SPM2.The brain areas activated after needling at ST36 included the left hippocampus,the left orbital cortex,the left infralimbic cortex,the left olfactory cortex,the left cerebellum and the left pons.In the sham-point group,the activated regions were similar to those in the ST36 group.However,the ST36 group showed greater activation in the cerebellum and pons than the sham-point group.These findings suggest that long-term acupuncture treatment has targeted regulatory effects on multiple brain regions in rats with Alzheimer＇s disease.展开更多
Due to the large-scale production and wide applications, many nanoparticles(NPs) enter wastewater treatment plants and accumulate in activated sludge. It is reported that titanium dioxide(Ti O2) NPs show severe damage...Due to the large-scale production and wide applications, many nanoparticles(NPs) enter wastewater treatment plants and accumulate in activated sludge. It is reported that titanium dioxide(Ti O2) NPs show severe damage to many model microbes. However, it is still unknown whether the long-term(e.g., 100 d) presence of Ti O2 NPs would affect the performance of sludge fermentation. In this study, long-term exposure experiments(105 d)were conducted to investigate the potential risk of Ti O2 NPs to sludge fermentation system. It is found that the presence of environmentally relevant [6 mg·(g TSS)-1] and higher [150 mg·(g TSS)-1] concentrations of Ti O2 NPs does not affect methane production from sludge fermentation. The analysis of fluorescence in situ hybridization indicates that these concentrations of Ti O2 NPs present marginal influences on abundances of bacteria and methanogenic archaea in sludge fermentation system. The viability of sludge microorganisms and activities of key enzymes related to methane production such as protease, acetate kinase, and coenzyme F420 are unchanged by the long-term presence of 6 and 150 mg·(g TSS)-1of Ti O2 NPs. Further investigations reveal that the insolubility of NPs and the protection role of sludge extracellular polymeric substances are the main reasons for the marginal influence of Ti O2 NPs on sludge fermentation.展开更多
基金financially supported by the Open Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment(No.SKLGP2021K008)the National Natural Science Foundation of China(41907247)。
文摘The failure of the 2017 Xinmo catastrophic rockslide in Maoxian County, Sichuan, Southwest China was a combined effect of long-term and shortterm triggering factors. Field investigation, historical data collection, laboratory tests, chemical and microstructure analysis and numerical simulations were adopted herein to reveal the initiation and failure mechanism of the Xinmo rockslide. The analytical results showed that this failure involved the coupling of several triggering factors. The initial cracks in the rock mass were induced by historical earthquakes due to the convex topography and the direction effect. Rock masses from the source area of the Xinmo rockslide contain water-sensitive minerals, i.e., albite and chamosite, and the easily oxidized chemical element Fe, resulting in obvious strength deterioration under the action of water. The scanning electron microscopy(SEM) experimental results indicated that the internal structure of the rock mass is conducive to weathering. The compressive and shear strengths of the rock mass were reduced due to freeze-thaw cycles and weathering. The antecedent rainfall further deteriorated the stability of the slope, and stress and deformation accumulated continually in the locked section. Finally, the locked section sheared out, and the slope failed. An entrainment effect was observed in the Xinmo rockslide due to the presence of old landslide deposits and the antecedent rainfall, resulting in an amplification of the catastrophic rockslide. A simplified three dimensional analysis model was established in this study to reveal the influence of the triggering factors on the failure mechanism of the Xinmo rockslide.
基金supported by the National Basic Research Program of China(973 Program),No.2006CB504505,2012CB518504the National Natural Science Foundation of China,No.90709027+1 种基金the Student's Platform for Innovation and Entrepreneurship Training Program of Southern Medical University of China,No.201512121165the Doctoral Foundation of Guangdong Medical University of China,No.2XB13058
文摘The acute effect of acupuncture on Alzheimer＇s disease,i.e.,on brain activation during treatment,has been reported.However,the effect of long-term acupuncture on brain activation in Alzheimer＇s disease is unclear.Therefore,in this study,we performed long-term needling at Zusanli（ST36）or a sham point（1.5 mm lateral to ST36）in a rat Alzheimer＇s disease model,for 30 minutes,once per day,for 30 days.The rats underwent 18F-fluorodeoxyglucose positron emission tomography scanning.Positron emission tomography images were processed with SPM2.The brain areas activated after needling at ST36 included the left hippocampus,the left orbital cortex,the left infralimbic cortex,the left olfactory cortex,the left cerebellum and the left pons.In the sham-point group,the activated regions were similar to those in the ST36 group.However,the ST36 group showed greater activation in the cerebellum and pons than the sham-point group.These findings suggest that long-term acupuncture treatment has targeted regulatory effects on multiple brain regions in rats with Alzheimer＇s disease.
基金Supported by the National Hi-Tech Research and Development Program of China(863Program)(2011AA060903)the National Natural Science Foundation of China(41301558and 51278354)Shanghai Tongji Gao Tingyao Environmental Science & Technology Development Foundation(STGEF)
文摘Due to the large-scale production and wide applications, many nanoparticles(NPs) enter wastewater treatment plants and accumulate in activated sludge. It is reported that titanium dioxide(Ti O2) NPs show severe damage to many model microbes. However, it is still unknown whether the long-term(e.g., 100 d) presence of Ti O2 NPs would affect the performance of sludge fermentation. In this study, long-term exposure experiments(105 d)were conducted to investigate the potential risk of Ti O2 NPs to sludge fermentation system. It is found that the presence of environmentally relevant [6 mg·(g TSS)-1] and higher [150 mg·(g TSS)-1] concentrations of Ti O2 NPs does not affect methane production from sludge fermentation. The analysis of fluorescence in situ hybridization indicates that these concentrations of Ti O2 NPs present marginal influences on abundances of bacteria and methanogenic archaea in sludge fermentation system. The viability of sludge microorganisms and activities of key enzymes related to methane production such as protease, acetate kinase, and coenzyme F420 are unchanged by the long-term presence of 6 and 150 mg·(g TSS)-1of Ti O2 NPs. Further investigations reveal that the insolubility of NPs and the protection role of sludge extracellular polymeric substances are the main reasons for the marginal influence of Ti O2 NPs on sludge fermentation.
