AIM:To assess the effect of nitric oxide (NO) on the large conductance potassium channel (BKCa) in isolated circular (CM) and sling (SM) muscle cells and muscle strips from the cat lower esophageal sphincter (LES) to ...AIM:To assess the effect of nitric oxide (NO) on the large conductance potassium channel (BKCa) in isolated circular (CM) and sling (SM) muscle cells and muscle strips from the cat lower esophageal sphincter (LES) to determine its regulation of resting tone and relaxation.METHODS:Freshly enzymatically-digested and isolated circular smooth muscle cells were prepared from each LES region.To study outward K + currents,the perforated patch clamp technique was employed.To assess LES resting tone and relaxation,muscle strips were mounted in perfused organ baths.RESULTS:(1) Electrophysiological recordings from isolated cells:(a) CM was more depolarized than SM (-39.7 ± 0.8mV vs-48.1 ± 1.6 mV,P < 0.001),and maximal outward current was similar (27.1 ± 1.5 pA/pF vs 25.7 ± 2.0 pA/pF,P > 0.05);(b) The NO donor sodium nitroprusside (SNP) increased outward currents only in CM (25.9 ± 1.9 to 46.7 ± 4.2 pA/pF,P < 0.001) but not SM (23.2 ± 3.1 to 27.0 ± 3.4 pA/pF,P > 0.05);(c) SNP added in the presence of the BK Ca antagonist iberiotoxin (IbTX) produced no increase in the outward current in CM (17.0 ± 2.8 vs 13.7 ± 2.2,P > 0.05);and (d) L-NNA caused a small insignificant inhibition of outward K + currents in both muscles;and (2) Muscle strip studies:(a) Blockade of the nerves with tetrodotoxin (TTX),or BK Ca with IbTX had no significant effect on resting tone of either muscle;and (b) SNP reduced tone in both muscles,and was unaffected by the presence of TTX or IbTX.CONCLUSION:Exogenous NO activates BK Ca only in CM of the cat.However,as opposed to other species,exogenous NO-induced relaxation is predominantly by a non-BK Ca mechanism,and endogenous NO has minimal effect on resting tone.展开更多
Miano area is one of the distinct major hydrocarbon producing fields of the Lower Indus basin. Lower Goru is the reservoir strait in this area. The aim of the present study is to exploit the channels reservoirs and ot...Miano area is one of the distinct major hydrocarbon producing fields of the Lower Indus basin. Lower Goru is the reservoir strait in this area. The aim of the present study is to exploit the channels reservoirs and other stratigraphic features in such a terrain where there is always a challenge for the geoscientist to search and exploit the channeled reservoirs. To resolve this issue we have utilized attribute analysis on high resolution 3D-seismic data for the detailed comparative studies for the channels. There are many astonishing features that are identified in the current study, which could not otherwise be easily enhanced with the help of 2D Seismic Data. Seismic attributes such as coherency, frequency (are also appropriate for lithological discrimination), which are sensitive to the channel edges are applied for the channel delineation and their geometrical analysis. Spectral decomposition techniques are also applied for the delineation of channels and to appropriately select the best band for channels identification. Three types of channel geometries are recognized: 1) highly sinuous channel;2) narrow-broad meandering belts;3) moderate to high sinuous channel. NW-SE, N-W trending faults can be helpful to compartmentalize the reservoir. Instantaneous and dominant frequency are more beneficial for further field development based on Gamma Ray logs from nearby drilled wells and dimensional perspectives analysis of the channel reservoir.展开更多
下刚果—刚果扇盆地为深水浊积岩油气勘探成功的典型含油气盆地。盆内广泛发育的浊积水道为重要储层类型,蕴含丰富的油气资源。前人从构造和沉积等角度对深水水道沉积模式及控制因素进行了大量研究,取得了长足进展(Henry et al.,2019;...下刚果—刚果扇盆地为深水浊积岩油气勘探成功的典型含油气盆地。盆内广泛发育的浊积水道为重要储层类型,蕴含丰富的油气资源。前人从构造和沉积等角度对深水水道沉积模式及控制因素进行了大量研究,取得了长足进展(Henry et al.,2019;陈华等,2021)。然而也有大量实钻资料表明水道体系内部砂体期次的沉积发育和叠置关系非常复杂,储层非均质性很强(张文彪等,2017)。展开更多
In the Fuyu Reservoir of Songliao Basin, there occur a series of well-developed peculiar shallow lake delta facies, which can be divided to such three ones as the upper delta plain subfacies, the lower delta plain sub...In the Fuyu Reservoir of Songliao Basin, there occur a series of well-developed peculiar shallow lake delta facies, which can be divided to such three ones as the upper delta plain subfacies, the lower delta plain subfacies, and the delta front subfacies. Among them the upper delta plain subfacies mainly grows proximal distributary channels; the lower delta plain subfacies mainly grows distal ones. The entire Fuyu Reservoir has mainly developed 7 kinds of distributary channel patterns： proximal/ distal meandering type distributary channels, proximal/distal low-sinuosity type distributary channels, proximal/distal straight type distributary channels, and subaqueous distributary channels. Among these patterns, the proximal and distal meandering type distributary channels have bigger thickness of point bar and better sorting and low content of mud; moreover, they are the major reservoirs and occur in the bottom of Quan-4th member. The sandbars of the subaqueous distributary channels have higher mud content, and serve as the poorer reservoirs, and mainly occur in the top of Quan-4th member.展开更多
River cutoff works have been implemented on Lower Jingjiang section for 30 years. Engineering practices have shown that channel straightening has been the river regulation measure for the permanent control of the mean...River cutoff works have been implemented on Lower Jingjiang section for 30 years. Engineering practices have shown that channel straightening has been the river regulation measure for the permanent control of the meandering Lower Jingjiang section. River cutoff have been carried out in accordance with the evolution property of meandering rivers and these works have brought about expected benefits. It has also been noted that certain aspects in river cutoff had not been fully understood. River cutoff is a dynamic engineering. River channel evolution properties shall be fully understood so as to adroitly guide actions according to circumstances in cutoff works. In addition, river channel evolution observation and engineering effectiveness monitoring should be strengthened with a view to update the designs. The diversion canals for channel shortening are of great importance that will account for the success or failure of river cutoff works. The newly formed river channels and the river regime control works on the adjacent upper and lower reaches are guarantees for river cutoff works to be brought into play in the long run.展开更多
Relative straight channel of the middle and upper reaches of Ganjiang has been formed due to thecontraction of mountains and hills being composed of bedrocks on both banks of the river. But however, At the lower reach...Relative straight channel of the middle and upper reaches of Ganjiang has been formed due to thecontraction of mountains and hills being composed of bedrocks on both banks of the river. But however, At the lower reaches, branching channel predominates due to limited contracting force of the river banks as the evolution and development of branching channels are closely related with locations and controle effect of nodal points. There are sufficient water containing less sediments in Ganjiang River where the sharp rise and fall of the flow discharge makes the grain size of the particles rather coars. Gravels mingled with sand dominate the channel bed and components of central bars are also much coarser than those in sandy bed of the middle and lower reaches of the Yangtze River.展开更多
基金Supported by A Postgraduate Fellowship Award to L'Heureux MC from the Department of Medicine,University of Torontoa doctoral research studentship and an Operating Grant from the Canadian Institutes of Health Research(Gaisano HY and Diamant NE)
文摘AIM:To assess the effect of nitric oxide (NO) on the large conductance potassium channel (BKCa) in isolated circular (CM) and sling (SM) muscle cells and muscle strips from the cat lower esophageal sphincter (LES) to determine its regulation of resting tone and relaxation.METHODS:Freshly enzymatically-digested and isolated circular smooth muscle cells were prepared from each LES region.To study outward K + currents,the perforated patch clamp technique was employed.To assess LES resting tone and relaxation,muscle strips were mounted in perfused organ baths.RESULTS:(1) Electrophysiological recordings from isolated cells:(a) CM was more depolarized than SM (-39.7 ± 0.8mV vs-48.1 ± 1.6 mV,P < 0.001),and maximal outward current was similar (27.1 ± 1.5 pA/pF vs 25.7 ± 2.0 pA/pF,P > 0.05);(b) The NO donor sodium nitroprusside (SNP) increased outward currents only in CM (25.9 ± 1.9 to 46.7 ± 4.2 pA/pF,P < 0.001) but not SM (23.2 ± 3.1 to 27.0 ± 3.4 pA/pF,P > 0.05);(c) SNP added in the presence of the BK Ca antagonist iberiotoxin (IbTX) produced no increase in the outward current in CM (17.0 ± 2.8 vs 13.7 ± 2.2,P > 0.05);and (d) L-NNA caused a small insignificant inhibition of outward K + currents in both muscles;and (2) Muscle strip studies:(a) Blockade of the nerves with tetrodotoxin (TTX),or BK Ca with IbTX had no significant effect on resting tone of either muscle;and (b) SNP reduced tone in both muscles,and was unaffected by the presence of TTX or IbTX.CONCLUSION:Exogenous NO activates BK Ca only in CM of the cat.However,as opposed to other species,exogenous NO-induced relaxation is predominantly by a non-BK Ca mechanism,and endogenous NO has minimal effect on resting tone.
文摘Miano area is one of the distinct major hydrocarbon producing fields of the Lower Indus basin. Lower Goru is the reservoir strait in this area. The aim of the present study is to exploit the channels reservoirs and other stratigraphic features in such a terrain where there is always a challenge for the geoscientist to search and exploit the channeled reservoirs. To resolve this issue we have utilized attribute analysis on high resolution 3D-seismic data for the detailed comparative studies for the channels. There are many astonishing features that are identified in the current study, which could not otherwise be easily enhanced with the help of 2D Seismic Data. Seismic attributes such as coherency, frequency (are also appropriate for lithological discrimination), which are sensitive to the channel edges are applied for the channel delineation and their geometrical analysis. Spectral decomposition techniques are also applied for the delineation of channels and to appropriately select the best band for channels identification. Three types of channel geometries are recognized: 1) highly sinuous channel;2) narrow-broad meandering belts;3) moderate to high sinuous channel. NW-SE, N-W trending faults can be helpful to compartmentalize the reservoir. Instantaneous and dominant frequency are more beneficial for further field development based on Gamma Ray logs from nearby drilled wells and dimensional perspectives analysis of the channel reservoir.
文摘下刚果—刚果扇盆地为深水浊积岩油气勘探成功的典型含油气盆地。盆内广泛发育的浊积水道为重要储层类型,蕴含丰富的油气资源。前人从构造和沉积等角度对深水水道沉积模式及控制因素进行了大量研究,取得了长足进展(Henry et al.,2019;陈华等,2021)。然而也有大量实钻资料表明水道体系内部砂体期次的沉积发育和叠置关系非常复杂,储层非均质性很强(张文彪等,2017)。
文摘In the Fuyu Reservoir of Songliao Basin, there occur a series of well-developed peculiar shallow lake delta facies, which can be divided to such three ones as the upper delta plain subfacies, the lower delta plain subfacies, and the delta front subfacies. Among them the upper delta plain subfacies mainly grows proximal distributary channels; the lower delta plain subfacies mainly grows distal ones. The entire Fuyu Reservoir has mainly developed 7 kinds of distributary channel patterns： proximal/ distal meandering type distributary channels, proximal/distal low-sinuosity type distributary channels, proximal/distal straight type distributary channels, and subaqueous distributary channels. Among these patterns, the proximal and distal meandering type distributary channels have bigger thickness of point bar and better sorting and low content of mud; moreover, they are the major reservoirs and occur in the bottom of Quan-4th member. The sandbars of the subaqueous distributary channels have higher mud content, and serve as the poorer reservoirs, and mainly occur in the top of Quan-4th member.
文摘River cutoff works have been implemented on Lower Jingjiang section for 30 years. Engineering practices have shown that channel straightening has been the river regulation measure for the permanent control of the meandering Lower Jingjiang section. River cutoff have been carried out in accordance with the evolution property of meandering rivers and these works have brought about expected benefits. It has also been noted that certain aspects in river cutoff had not been fully understood. River cutoff is a dynamic engineering. River channel evolution properties shall be fully understood so as to adroitly guide actions according to circumstances in cutoff works. In addition, river channel evolution observation and engineering effectiveness monitoring should be strengthened with a view to update the designs. The diversion canals for channel shortening are of great importance that will account for the success or failure of river cutoff works. The newly formed river channels and the river regime control works on the adjacent upper and lower reaches are guarantees for river cutoff works to be brought into play in the long run.
基金Under the auspices of the National Natural Science Foundation of China (No. 49971014)
文摘Relative straight channel of the middle and upper reaches of Ganjiang has been formed due to thecontraction of mountains and hills being composed of bedrocks on both banks of the river. But however, At the lower reaches, branching channel predominates due to limited contracting force of the river banks as the evolution and development of branching channels are closely related with locations and controle effect of nodal points. There are sufficient water containing less sediments in Ganjiang River where the sharp rise and fall of the flow discharge makes the grain size of the particles rather coars. Gravels mingled with sand dominate the channel bed and components of central bars are also much coarser than those in sandy bed of the middle and lower reaches of the Yangtze River.
