High-resolution bathymetric and partial seismic data were utilized to determine the characteristics and distribution of mass-transport deposits(MTDs)in the Xisha area,North of the South China Sea.Many isolated carbona...High-resolution bathymetric and partial seismic data were utilized to determine the characteristics and distribution of mass-transport deposits(MTDs)in the Xisha area,North of the South China Sea.Many isolated carbonate platforms are found in this area,providing mass-wasting materials as a sediment source for MTDs.The MTDs in the study area were divided into three types(slide,slump,and debris flow)based on their rheological properties.The MTDs were mostly distributed at the toe of the carbonate platform slope,where a large amount of carbonate debris accumulated.A total of 32 MTDs were identified on the carbonate platform slopes.A systematic assessment of the MTD morphometric parameters showed that their total area covered 2225.2 km2,with the largest MTD covering 354.1 km2.These MTDs differ largely from the MTDs of other areas,especially in terms of sediment compositions and deposit processes.Gullies and channels on the slope and reefs on the top of the platform act as sediment conduits and carbonate-producing sources,respectively,playing vital roles in the distribution and generation of gravity flow deposits.The development model proposed in this work states that reefs disintegrate into carbonate debris and mix with seawater to form gravity flows,which scour the seafloor and accumulate at the downslope,eventually resulting in failure.Sediments from these failures turn into gravity flows,flowing into submarine canyons and channels.The results of this research further our understanding of the development pattern of MTDs in a carbonate setting.展开更多
OBJECTIVE: To investigate the effect of electroacupuncture(EA) of acupoints Neiguan(PC 6) and Tianquan(PC 2) on the skin temperature, blood perfusion, and alpha1-and beta2-adrenoreceptor(α1-AR and β2-AR) protein and...OBJECTIVE: To investigate the effect of electroacupuncture(EA) of acupoints Neiguan(PC 6) and Tianquan(PC 2) on the skin temperature, blood perfusion, and alpha1-and beta2-adrenoreceptor(α1-AR and β2-AR) protein and m RNA level in rats with acute myocardial ischemia.METHODS: Thirty male adult Wistar rats [(230 ±20) g] were randomly assigned into five groups(n = 6 each): a control group, sham operation group, model group, model group treated with EA at low frequency(L-EA, 2 Hz, 1 m A) and model group treated with EA at high frequency(H-EA, 100 Hz, 1 m A). The rat model was prepared by ligating the left anterior descending coronary artery. Electroacupuncture was performed at the left Neiguan(PC 6) for 20 min daily for 3 d. After the 3 rd time of the treatment, measurements of skin blood perfusion and temperature in Neiguan(PC 6) and Tianquan(PC 2) in all groups were made by laser speckle contrast imaging and infrared thermal image instrument. Real-time PCR and ELISA were used to measure m RNA level and protein level of α1-AR andβ2-AR in the skin tissues of Neiguan(PC 6) and Tianquan(PC 2), respectively. Serum levels of c Tn T and electrocardiogram were used to identify the state of myocardium.RESULTS: In the group receiving electroacupunture at Neiguan(PC 6), compared with control group,the skin temperature, blood perfusion, and β2-AR m RNA and protein level of model group significantly decreased(P < 0.05), α1-AR m RNA and protein level of model group significantly increased(P < 0.05);compared with model group, the skin temperature,blood perfusion, and β2-AR m RNA and protein level of L-EA significantly increased(P < 0.05), α1-AR m RNA and protein level of L-EA and H-EA significantly decreased(P < 0.05). The same trend has taken place in the former four groups of the Tianquan(PC 2).CONCLUSION: Low-or high-frequency electroacupuncture can improve the skin temperature and blood perfusion which may be induced by decreasingthelevelofα1-ARandincreasingthelevelofβ2-AR of the Neiguan(PC 6) and Tianquan(PC 2) in the rat with acute myocaidial ischemia.展开更多
基金This work was supported by the Key Research and Development Program of Hainan Province(No.ZDYF2020209)the National Natural Science Foundation of China(No.42176083)the Key-Area Research and Deve-lopment Program of Guangdong Province(No.2020B1111020002).
文摘High-resolution bathymetric and partial seismic data were utilized to determine the characteristics and distribution of mass-transport deposits(MTDs)in the Xisha area,North of the South China Sea.Many isolated carbonate platforms are found in this area,providing mass-wasting materials as a sediment source for MTDs.The MTDs in the study area were divided into three types(slide,slump,and debris flow)based on their rheological properties.The MTDs were mostly distributed at the toe of the carbonate platform slope,where a large amount of carbonate debris accumulated.A total of 32 MTDs were identified on the carbonate platform slopes.A systematic assessment of the MTD morphometric parameters showed that their total area covered 2225.2 km2,with the largest MTD covering 354.1 km2.These MTDs differ largely from the MTDs of other areas,especially in terms of sediment compositions and deposit processes.Gullies and channels on the slope and reefs on the top of the platform act as sediment conduits and carbonate-producing sources,respectively,playing vital roles in the distribution and generation of gravity flow deposits.The development model proposed in this work states that reefs disintegrate into carbonate debris and mix with seawater to form gravity flows,which scour the seafloor and accumulate at the downslope,eventually resulting in failure.Sediments from these failures turn into gravity flows,flowing into submarine canyons and channels.The results of this research further our understanding of the development pattern of MTDs in a carbonate setting.
基金Supported by the Law of Sympathetic Nerve Reaction and Receptor Molecular Response in Relevant Acupoints in Different Myocardial Conditions(No.81373558)
文摘OBJECTIVE: To investigate the effect of electroacupuncture(EA) of acupoints Neiguan(PC 6) and Tianquan(PC 2) on the skin temperature, blood perfusion, and alpha1-and beta2-adrenoreceptor(α1-AR and β2-AR) protein and m RNA level in rats with acute myocardial ischemia.METHODS: Thirty male adult Wistar rats [(230 ±20) g] were randomly assigned into five groups(n = 6 each): a control group, sham operation group, model group, model group treated with EA at low frequency(L-EA, 2 Hz, 1 m A) and model group treated with EA at high frequency(H-EA, 100 Hz, 1 m A). The rat model was prepared by ligating the left anterior descending coronary artery. Electroacupuncture was performed at the left Neiguan(PC 6) for 20 min daily for 3 d. After the 3 rd time of the treatment, measurements of skin blood perfusion and temperature in Neiguan(PC 6) and Tianquan(PC 2) in all groups were made by laser speckle contrast imaging and infrared thermal image instrument. Real-time PCR and ELISA were used to measure m RNA level and protein level of α1-AR andβ2-AR in the skin tissues of Neiguan(PC 6) and Tianquan(PC 2), respectively. Serum levels of c Tn T and electrocardiogram were used to identify the state of myocardium.RESULTS: In the group receiving electroacupunture at Neiguan(PC 6), compared with control group,the skin temperature, blood perfusion, and β2-AR m RNA and protein level of model group significantly decreased(P < 0.05), α1-AR m RNA and protein level of model group significantly increased(P < 0.05);compared with model group, the skin temperature,blood perfusion, and β2-AR m RNA and protein level of L-EA significantly increased(P < 0.05), α1-AR m RNA and protein level of L-EA and H-EA significantly decreased(P < 0.05). The same trend has taken place in the former four groups of the Tianquan(PC 2).CONCLUSION: Low-or high-frequency electroacupuncture can improve the skin temperature and blood perfusion which may be induced by decreasingthelevelofα1-ARandincreasingthelevelofβ2-AR of the Neiguan(PC 6) and Tianquan(PC 2) in the rat with acute myocaidial ischemia.
