The Experts below are selected from a list of 640176 Experts worldwide ranked by ideXlab platform
James N Weiss - One of the best experts on this subject based on the ideXlab platform.
-
action potential duration restitution and alternans in rabbit ventricular myocytes the key role of intracellular calcium cycling
Circulation Research, 2005Co-Authors: Joshua I Goldhaber, Laihua Xie, Tan Duong, Christi Motter, Kien Khuu, James N WeissAbstract:Action potential duration (APD) restitution properties and repolarization alternans are thought to be important arrhythmogenic factors. We investigated the role of intracellular calcium (Ca2+i) cycling in regulating APD restitution slope and repolarization (APD) alternans in patch-clamped rabbit ventricular myocytes at 34 to 36 degrees C, using the perforated or ruptured patch clamp techniques with Fura-2-AM to record Ca2+i. When APD restitution was measured by either the standard extrastimulus (S1S2) Method or the Dynamic rapid pacing Method, the maximum APD restitution slope exceeded 1 by both Methods, but was more shallow with the Dynamic Method. These differences were associated with greater Ca2+i accumulation during Dynamic pacing. The onset of APD alternans occurred at diastolic intervals at which the APD restitution slope was significantly <1 and was abolished by suppressing sarcoplasmic reticulum (SR) Ca2+i cycling with thapsigargin and ryanodine, or buffering the global Ca2+i transient with BAPTA-AM or BAPTA. Thapsigargin and ryanodine flattened APD restitution slope to <1 when measured by the Dynamic Method, but not by the S1S2 Method. BAPTA-AM or BAPTA failed to flatten APD restitution slope to <1 by either Method. In conclusion, APD alternans requires intact Ca2+i cycling and is not reliably predicted by APD restitution slope when Ca2+i cycling is suppressed. Ca2+i cycling may contribute to differences between APD restitution curves measured by S1S2 versus Dynamic pacing protocols by inducing short-term memory effects related to pacing-dependent Ca2+i accumulation.
-
action potential duration restitution and alternans in rabbit ventricular myocytes the key role of intracellular calcium cycling
Circulation Research, 2005Co-Authors: Joshua I Goldhaber, Tan Duong, Christi Motter, Kien Khuu, James N WeissAbstract:Action potential duration (APD) restitution properties and repolarization alternans are thought to be important arrhythmogenic factors. We investigated the role of intracellular calcium (Ca2+i) cycling in regulating APD restitution slope and repolarization (APD) alternans in patch-clamped rabbit ventricular myocytes at 34 to 36°C, using the perforated or ruptured patch clamp techniques with Fura-2-AM to record Ca2+i. When APD restitution was measured by either the standard extrastimulus (S1S2) Method or the Dynamic rapid pacing Method, the maximum APD restitution slope exceeded 1 by both Methods, but was more shallow with the Dynamic Method. These differences were associated with greater Ca2+i accumulation during Dynamic pacing. The onset of APD alternans occurred at diastolic intervals at which the APD restitution slope was significantly <1 and was abolished by suppressing sarcoplasmic reticulum (SR) Ca2+i cycling with thapsigargin and ryanodine, or buffering the global Ca2+i transient with BAPTA-AM or BAPTA. Thapsigargin and ryanodine flattened APD restitution slope to <1 when measured by the Dynamic Method, but not by the S1S2 Method. BAPTA-AM or BAPTA failed to flatten APD restitution slope to <1 by either Method. In conclusion, APD alternans requires intact Ca2+i cycling and is not reliably predicted by APD restitution slope when Ca2+i cycling is suppressed. Ca2+i cycling may contribute to differences between APD restitution curves measured by S1S2 versus Dynamic pacing protocols by inducing short-term memory effects related to pacing-dependent Ca2+i accumulation.
Fu-an Wang - One of the best experts on this subject based on the ideXlab platform.
-
measurement and correlation of solubilities of cefpirome sulfate in aqueous alcohol solution between 278 15 and 308 15 k
Journal of Chemical & Engineering Data, 2010Co-Authors: Fu-an Wang, Baozeng RenAbstract:The solubilities of cefpirome sulfate in water + (methanol, ethanol, 1-propanol, or 2-propanol) solvent mixtures have been measured using a Dynamic Method at temperature ranging from (278.15 to 318.15) K at atmospheric pressure. A solubility equation was proposed and verified by experimental results. The dissolution enthalpy and dissolution entropy have been calculated from the solubility data. The interactions between solute and solvent were discussed.
-
solubilities of menadione sodium bisulfite in water methanol ethanol 1 propanol 2 propanol 1 2 propanediol and glycerin respectively from 297 67 to 337 76 k
Journal of Chemical & Engineering Data, 2008Co-Authors: Cheng-ying Song, Hong-zhi Shen, Jian-hong Zhao, Liu-cheng Wang, Fu-an WangAbstract:The solubilities of menadione sodium bisulfite in water + (methanol, ethanol, 1-propanol, 2-propanol, 1,2-propanediol, and glycerin, respectively) have been determined experimentally from (297.67 to 337.76) K by a Dynamic Method. The experimental data were correlated with the modified Apelblat equation.
Joshua I Goldhaber - One of the best experts on this subject based on the ideXlab platform.
-
action potential duration restitution and alternans in rabbit ventricular myocytes the key role of intracellular calcium cycling
Circulation Research, 2005Co-Authors: Joshua I Goldhaber, Laihua Xie, Tan Duong, Christi Motter, Kien Khuu, James N WeissAbstract:Action potential duration (APD) restitution properties and repolarization alternans are thought to be important arrhythmogenic factors. We investigated the role of intracellular calcium (Ca2+i) cycling in regulating APD restitution slope and repolarization (APD) alternans in patch-clamped rabbit ventricular myocytes at 34 to 36 degrees C, using the perforated or ruptured patch clamp techniques with Fura-2-AM to record Ca2+i. When APD restitution was measured by either the standard extrastimulus (S1S2) Method or the Dynamic rapid pacing Method, the maximum APD restitution slope exceeded 1 by both Methods, but was more shallow with the Dynamic Method. These differences were associated with greater Ca2+i accumulation during Dynamic pacing. The onset of APD alternans occurred at diastolic intervals at which the APD restitution slope was significantly <1 and was abolished by suppressing sarcoplasmic reticulum (SR) Ca2+i cycling with thapsigargin and ryanodine, or buffering the global Ca2+i transient with BAPTA-AM or BAPTA. Thapsigargin and ryanodine flattened APD restitution slope to <1 when measured by the Dynamic Method, but not by the S1S2 Method. BAPTA-AM or BAPTA failed to flatten APD restitution slope to <1 by either Method. In conclusion, APD alternans requires intact Ca2+i cycling and is not reliably predicted by APD restitution slope when Ca2+i cycling is suppressed. Ca2+i cycling may contribute to differences between APD restitution curves measured by S1S2 versus Dynamic pacing protocols by inducing short-term memory effects related to pacing-dependent Ca2+i accumulation.
-
action potential duration restitution and alternans in rabbit ventricular myocytes the key role of intracellular calcium cycling
Circulation Research, 2005Co-Authors: Joshua I Goldhaber, Tan Duong, Christi Motter, Kien Khuu, James N WeissAbstract:Action potential duration (APD) restitution properties and repolarization alternans are thought to be important arrhythmogenic factors. We investigated the role of intracellular calcium (Ca2+i) cycling in regulating APD restitution slope and repolarization (APD) alternans in patch-clamped rabbit ventricular myocytes at 34 to 36°C, using the perforated or ruptured patch clamp techniques with Fura-2-AM to record Ca2+i. When APD restitution was measured by either the standard extrastimulus (S1S2) Method or the Dynamic rapid pacing Method, the maximum APD restitution slope exceeded 1 by both Methods, but was more shallow with the Dynamic Method. These differences were associated with greater Ca2+i accumulation during Dynamic pacing. The onset of APD alternans occurred at diastolic intervals at which the APD restitution slope was significantly <1 and was abolished by suppressing sarcoplasmic reticulum (SR) Ca2+i cycling with thapsigargin and ryanodine, or buffering the global Ca2+i transient with BAPTA-AM or BAPTA. Thapsigargin and ryanodine flattened APD restitution slope to <1 when measured by the Dynamic Method, but not by the S1S2 Method. BAPTA-AM or BAPTA failed to flatten APD restitution slope to <1 by either Method. In conclusion, APD alternans requires intact Ca2+i cycling and is not reliably predicted by APD restitution slope when Ca2+i cycling is suppressed. Ca2+i cycling may contribute to differences between APD restitution curves measured by S1S2 versus Dynamic pacing protocols by inducing short-term memory effects related to pacing-dependent Ca2+i accumulation.
Yunong Zhang - One of the best experts on this subject based on the ideXlab platform.
-
different level redundancy resolution and its equivalent relationship analysis for robot manipulators using gradient descent and zhang s neural Dynamic Methods
IEEE Transactions on Industrial Electronics, 2012Co-Authors: Yunong ZhangAbstract:To solve the inverse kinematic problem of redundant robot manipulators, two redundancy-resolution schemes are investigated: one is resolved at joint-velocity level, and the other is resolved at joint-acceleration level. Both schemes are reformulated as a quadratic programming (QP) problem. Two recurrent neural networks (RNNs) are then developed for the online solution of the resultant QP problem. The first RNN solver is based on the gradient-descent Method and is termed as gradient neural network (GNN). The other solver is based on Zhang 's neural-Dynamic Method and is termed as Zhang neural network (ZNN). The computer simulations performed on a three-link planar robot arm and the PUMA560 manipulator demonstrate the efficacy of the two redundancy-resolution schemes and two RNN QP-solvers presented, as well as the superiority of the ZNN QP-solver compared to the GNN one. More importantly, the simulation results show that the solutions of the two presented schemes fit well with each other, i.e., the two different-level redundancy-resolution schemes could be equivalent in some sense. The theoretical analysis based on the gradient-descent Method and Zhang 's neural-Dynamic Method further substantiates the new finding about the different-level redundancy-resolution equivalence.
-
effective parameter range for equivalence of velocity level and acceleration level redundancy resolution schemes
Physics Letters A, 2012Co-Authors: Yunong Zhang, Dongsheng Guo, Lin XiaoAbstract:Abstract This Letter shows the equivalence of the velocity-level and acceleration-level redundancy resolution schemes by using so-called Zhang et al.ʼs neural-Dynamic Method. In addition, the equivalence requires that a design parameter be sufficiently large. But how large should it be? The effective range of such a design parameter is thus determined by means of the 2%-difference rule and the runtime of the computer-simulations.
-
Zhang Neural Networks and Neural-Dynamic Method
2011Co-Authors: Yunong ZhangAbstract:The real-time solution to a mathematical problem arises in numerous fields of science, engineering, and business. It is usually an essential part of many solutions, e.g., matrix/vector computation, optimisation, control theory, kinematics, signal processing, and pattern recognition. In recent years, due to the in-depth research on neural networks, numerous recurrent neural networks (RNN) based on the gradient-based Method have been developed and investigated. Particularly, some simple neural networks were proposed to solve linear programming problems in real time and implemented on analogue circuits. In this book, ZNN, ZD or ZND theory formalises these problems and solutions in the time-varying context and provides compact models that could solve those Dynamic problems.
Tan Duong - One of the best experts on this subject based on the ideXlab platform.
-
action potential duration restitution and alternans in rabbit ventricular myocytes the key role of intracellular calcium cycling
Circulation Research, 2005Co-Authors: Joshua I Goldhaber, Laihua Xie, Tan Duong, Christi Motter, Kien Khuu, James N WeissAbstract:Action potential duration (APD) restitution properties and repolarization alternans are thought to be important arrhythmogenic factors. We investigated the role of intracellular calcium (Ca2+i) cycling in regulating APD restitution slope and repolarization (APD) alternans in patch-clamped rabbit ventricular myocytes at 34 to 36 degrees C, using the perforated or ruptured patch clamp techniques with Fura-2-AM to record Ca2+i. When APD restitution was measured by either the standard extrastimulus (S1S2) Method or the Dynamic rapid pacing Method, the maximum APD restitution slope exceeded 1 by both Methods, but was more shallow with the Dynamic Method. These differences were associated with greater Ca2+i accumulation during Dynamic pacing. The onset of APD alternans occurred at diastolic intervals at which the APD restitution slope was significantly <1 and was abolished by suppressing sarcoplasmic reticulum (SR) Ca2+i cycling with thapsigargin and ryanodine, or buffering the global Ca2+i transient with BAPTA-AM or BAPTA. Thapsigargin and ryanodine flattened APD restitution slope to <1 when measured by the Dynamic Method, but not by the S1S2 Method. BAPTA-AM or BAPTA failed to flatten APD restitution slope to <1 by either Method. In conclusion, APD alternans requires intact Ca2+i cycling and is not reliably predicted by APD restitution slope when Ca2+i cycling is suppressed. Ca2+i cycling may contribute to differences between APD restitution curves measured by S1S2 versus Dynamic pacing protocols by inducing short-term memory effects related to pacing-dependent Ca2+i accumulation.
-
action potential duration restitution and alternans in rabbit ventricular myocytes the key role of intracellular calcium cycling
Circulation Research, 2005Co-Authors: Joshua I Goldhaber, Tan Duong, Christi Motter, Kien Khuu, James N WeissAbstract:Action potential duration (APD) restitution properties and repolarization alternans are thought to be important arrhythmogenic factors. We investigated the role of intracellular calcium (Ca2+i) cycling in regulating APD restitution slope and repolarization (APD) alternans in patch-clamped rabbit ventricular myocytes at 34 to 36°C, using the perforated or ruptured patch clamp techniques with Fura-2-AM to record Ca2+i. When APD restitution was measured by either the standard extrastimulus (S1S2) Method or the Dynamic rapid pacing Method, the maximum APD restitution slope exceeded 1 by both Methods, but was more shallow with the Dynamic Method. These differences were associated with greater Ca2+i accumulation during Dynamic pacing. The onset of APD alternans occurred at diastolic intervals at which the APD restitution slope was significantly <1 and was abolished by suppressing sarcoplasmic reticulum (SR) Ca2+i cycling with thapsigargin and ryanodine, or buffering the global Ca2+i transient with BAPTA-AM or BAPTA. Thapsigargin and ryanodine flattened APD restitution slope to <1 when measured by the Dynamic Method, but not by the S1S2 Method. BAPTA-AM or BAPTA failed to flatten APD restitution slope to <1 by either Method. In conclusion, APD alternans requires intact Ca2+i cycling and is not reliably predicted by APD restitution slope when Ca2+i cycling is suppressed. Ca2+i cycling may contribute to differences between APD restitution curves measured by S1S2 versus Dynamic pacing protocols by inducing short-term memory effects related to pacing-dependent Ca2+i accumulation.
