This paper introduces a new spontaneous potential log model for the case in which formation resistivity is not piecewise constant. The spontaneous potential satisfies an elliptic boundary value problem with jump condi...This paper introduces a new spontaneous potential log model for the case in which formation resistivity is not piecewise constant. The spontaneous potential satisfies an elliptic boundary value problem with jump conditions on the interfaces. It has beer/ shown that the elliptic interface problem has a unique weak solution. Furthermore, a jump condition capturing finite difference scheme is proposed and applied to solve such elliptic problems. Numerical results show validity and effectiveness of the proposed method.展开更多
Spontaneous potential well-logging is one of the important techniques in petroleum exploitation. A spontaneous potential satisfies an elliptic equivalued surface boundary value problem with discontinuous interface con...Spontaneous potential well-logging is one of the important techniques in petroleum exploitation. A spontaneous potential satisfies an elliptic equivalued surface boundary value problem with discontinuous interface conditions. In practice, the measuring electrode is so small that we can simplify the corresponding equivalued surface to a point. In this paper, we give a positive answer to this approximation process:when the equivalued surface shrinks to a point, the solution of the original equivalued surface boundary value problem converges to the solution of the corresponding limit boundary value problem.展开更多
Voltage-gated sodium channels(VGSCs)are transiently expressed in cochlear hair cells before hearing onset and play an indispensable role in shaping spontaneous activity.In this study,we showed that Na^+currents shaped...Voltage-gated sodium channels(VGSCs)are transiently expressed in cochlear hair cells before hearing onset and play an indispensable role in shaping spontaneous activity.In this study,we showed that Na^+currents shaped the spontaneous action potentials in developing mouse inner hair cells(IHCs)by decreasing the time required for the membrane potential to reach the action-potential threshold.In immature IHCs,we identified 9 known VGSC subtypes(Navl.la-l.9ot),among which Navl.7a was the most highly expressed subtype and the main contributor to Na+currents in developing hair cells.Electrophysiological recordings of two cochlea-specific Navi.7 variants(CbmNavl.7a and CbmNavl.7b)revealed a novel loss-of-function mutation(C934R)at the extracellular linker between segments 5 and 6 of domain II.In addition,post-transcriptional modification events,such as alternative splicing and RNA editing,amended the gating properties and kinetic features of CbmNavl.7a(C934).These results provide molecular and functional characteristics of VGSCs in mammalian IHCs and their contributions to spontaneous physiological activity during cochlear maturation.展开更多
基金supported by the National Natural Science Foundation of China (No. 10431030)the Shanghai Natural Science Foundation (No. 08ZR1401100)
文摘This paper introduces a new spontaneous potential log model for the case in which formation resistivity is not piecewise constant. The spontaneous potential satisfies an elliptic boundary value problem with jump conditions on the interfaces. It has beer/ shown that the elliptic interface problem has a unique weak solution. Furthermore, a jump condition capturing finite difference scheme is proposed and applied to solve such elliptic problems. Numerical results show validity and effectiveness of the proposed method.
文摘Spontaneous potential well-logging is one of the important techniques in petroleum exploitation. A spontaneous potential satisfies an elliptic equivalued surface boundary value problem with discontinuous interface conditions. In practice, the measuring electrode is so small that we can simplify the corresponding equivalued surface to a point. In this paper, we give a positive answer to this approximation process:when the equivalued surface shrinks to a point, the solution of the original equivalued surface boundary value problem converges to the solution of the corresponding limit boundary value problem.
基金We thank Prof.Lin Chen(University of Science and Technology of China)and Dr.Juanmei Yang(Eye and ENT Hospital of Fudan University)for valuable help with cochlear microscopic anatomy.This work was supported by the National Natural Science Foundation of China(31571032,31771191.81730028)the National Basic Research Development Program of China(SQ2017YFSF080012)the Postdoctoral Science Foundation of China(2018M640407).
文摘Voltage-gated sodium channels(VGSCs)are transiently expressed in cochlear hair cells before hearing onset and play an indispensable role in shaping spontaneous activity.In this study,we showed that Na^+currents shaped the spontaneous action potentials in developing mouse inner hair cells(IHCs)by decreasing the time required for the membrane potential to reach the action-potential threshold.In immature IHCs,we identified 9 known VGSC subtypes(Navl.la-l.9ot),among which Navl.7a was the most highly expressed subtype and the main contributor to Na+currents in developing hair cells.Electrophysiological recordings of two cochlea-specific Navi.7 variants(CbmNavl.7a and CbmNavl.7b)revealed a novel loss-of-function mutation(C934R)at the extracellular linker between segments 5 and 6 of domain II.In addition,post-transcriptional modification events,such as alternative splicing and RNA editing,amended the gating properties and kinetic features of CbmNavl.7a(C934).These results provide molecular and functional characteristics of VGSCs in mammalian IHCs and their contributions to spontaneous physiological activity during cochlear maturation.
