The Experts below are selected from a list of 46776 Experts worldwide ranked by ideXlab platform
D Reiter - One of the best experts on this subject based on the ideXlab platform.
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the pattern of parallel edge plasma flows due to Pressure Gradients recycling and resonant magnetic perturbations in diii d
Physics of Plasmas, 2015Co-Authors: H Frerichs, O Schmitz, T E Evans, Y Feng, D ReiterAbstract:High resolution plasma transport simulations with the EMC3-EIRENE code have been performed to address the parallel plasma flow structure in the boundary of a poloidal divertor configuration with non-axisymmetric perturbations at DIII-D. Simulation results show that a checkerboard pattern of flows with alternating direction is generated inside the separatrix. This pattern is aligned with the position of the main resonances (i.e., where the safety factor is equal to rational values q=m/n for a perturbation field with base mode number n): m pairs of alternating forward and backward flow channel exist for each resonance. The poloidal oscillations are aligned with the subharmonic Melnikov function, which indicates that the plasma flow is generated by parallel Pressure Gradients along perturbed field lines. An additional scrape-off layer-like domain is introduced by the perturbed separatrix which guides field lines from the interior to the divertor targets, resulting in an enhanced outward flow that is consiste...
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the pattern of parallel edge plasma flows due to Pressure Gradients recycling and resonant magnetic perturbations in diii d
Physics of Plasmas, 2015Co-Authors: H Frerichs, O Schmitz, T E Evans, Y Feng, D ReiterAbstract:High resolution plasma transport simulations with the EMC3-EIRENE code have been performed to address the parallel plasma flow structure in the boundary of a poloidal divertor configuration with non-axisymmetric perturbations at DIII-D. Simulation results show that a checkerboard pattern of flows with alternating direction is generated inside the separatrix. This pattern is aligned with the position of the main resonances (i.e., where the safety factor is equal to rational values q=m/n for a perturbation field with base mode number n): m pairs of alternating forward and backward flow channel exist for each resonance. The poloidal oscillations are aligned with the subharmonic Melnikov function, which indicates that the plasma flow is generated by parallel Pressure Gradients along perturbed field lines. An additional scrape-off layer-like domain is introduced by the perturbed separatrix which guides field lines from the interior to the divertor targets, resulting in an enhanced outward flow that is consistent with the experimentally observed particle pump-out effect. However, while the lobe structure of the perturbed separatrix is very well reflected in the temperature profile, the same lobes can appear to be smaller in the flow profile due to a competition between high upstream Pressure and downstream particle sources driving flows in opposite directions.
James D Thomas - One of the best experts on this subject based on the ideXlab platform.
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relationship among diastolic intraventricular Pressure Gradients relaxation and preload impact of age and fitness
American Journal of Physiology-heart and Circulatory Physiology, 2006Co-Authors: Zoran B Popovic, Anand Prasad, Mario J Garcia, Armin Arbabzadeh, Allen G Borowski, Erika Dijk, Neil L Greenberg, Benjamin D Levine, James D ThomasAbstract:Diastolic intraventricular Pressure Gradients (IVPGs) are a measure of the ability of the ventricle to facilitate its filling using diastolic suction. We assessed 15 healthy young but sedentary sub...
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relationship of diastolic intraventricular Pressure Gradients and aerobic capacity in patients with diastolic heart failure
American Journal of Physiology-heart and Circulatory Physiology, 2005Co-Authors: Aleksandr Rovner, James D Thomas, Neil L Greenberg, Mario J GarciaAbstract:We sought to elucidate the relationship between diastolic intraventricular Pressure Gradients (IVPG) and exercise tolerance in patients with heart failure using color M-mode Doppler. Diastolic dysf...
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relationship between early diastolic intraventricular Pressure Gradients an index of elastic recoil and improvements in systolic and diastolic function
Circulation, 2001Co-Authors: Michael S Firstenberg, Mario J Garcia, Neil L Greenberg, Nicholas G Smedira, David L Prior, Patrick M Mccarthy, James D ThomasAbstract:Background Early diastolic intraventricular Pressure Gradients (IVPGs) have been proposed to relate to left ventricular (LV) elastic recoil and early ventricular “suction.” Animal studies have demo...
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estimation of diastolic intraventricular Pressure Gradients by doppler m mode echocardiography
American Journal of Physiology-heart and Circulatory Physiology, 2001Co-Authors: Neil L Greenberg, Mario J Garcia, Michael S Firstenberg, Pieter M Vandervoort, James D ThomasAbstract:Previous studies have shown that small intraventricular Pressure Gradients (IVPG) are important for efficient filling of the left ventricle (LV) and as a sensitive marker for ischemia. Unfortunately, there has previously been no way of measuring these noninvasively, severely limiting their research and clinical utility. Color Doppler M-mode (CMM) echocardiography provides a spatiotemporal velocity distribution along the inflow tract throughout diastole, which we hypothesized would allow direct estimation of IVPG by using the Euler equation. Digital CMM images, obtained simultaneously with intracardiac Pressure waveforms in six dogs, were processed by numerical differentiation for the Euler equation, then integrated to estimate IVPG and the total (left atrial to left ventricular apex) Pressure drop. CMM-derived estimates agreed well with invasive measurements (IVPG: y = 0.87x + 0.22, r = 0.96, P < 0.001, standard error of the estimate = 0.35 mmHg). Quantitative processing of CMM data allows accurate estimation of IVPG and tracking of changes induced by beta-adrenergic stimulation. This novel approach provides unique information on LV filling dynamics in an entirely noninvasive way that has previously not been available for assessment of diastolic filling and function.
Mario J Garcia - One of the best experts on this subject based on the ideXlab platform.
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relationship among diastolic intraventricular Pressure Gradients relaxation and preload impact of age and fitness
American Journal of Physiology-heart and Circulatory Physiology, 2006Co-Authors: Zoran B Popovic, Anand Prasad, Mario J Garcia, Armin Arbabzadeh, Allen G Borowski, Erika Dijk, Neil L Greenberg, Benjamin D Levine, James D ThomasAbstract:Diastolic intraventricular Pressure Gradients (IVPGs) are a measure of the ability of the ventricle to facilitate its filling using diastolic suction. We assessed 15 healthy young but sedentary sub...
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relationship of diastolic intraventricular Pressure Gradients and aerobic capacity in patients with diastolic heart failure
American Journal of Physiology-heart and Circulatory Physiology, 2005Co-Authors: Aleksandr Rovner, James D Thomas, Neil L Greenberg, Mario J GarciaAbstract:We sought to elucidate the relationship between diastolic intraventricular Pressure Gradients (IVPG) and exercise tolerance in patients with heart failure using color M-mode Doppler. Diastolic dysf...
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relationship between early diastolic intraventricular Pressure Gradients an index of elastic recoil and improvements in systolic and diastolic function
Circulation, 2001Co-Authors: Michael S Firstenberg, Mario J Garcia, Neil L Greenberg, Nicholas G Smedira, David L Prior, Patrick M Mccarthy, James D ThomasAbstract:Background Early diastolic intraventricular Pressure Gradients (IVPGs) have been proposed to relate to left ventricular (LV) elastic recoil and early ventricular “suction.” Animal studies have demo...
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estimation of diastolic intraventricular Pressure Gradients by doppler m mode echocardiography
American Journal of Physiology-heart and Circulatory Physiology, 2001Co-Authors: Neil L Greenberg, Mario J Garcia, Michael S Firstenberg, Pieter M Vandervoort, James D ThomasAbstract:Previous studies have shown that small intraventricular Pressure Gradients (IVPG) are important for efficient filling of the left ventricle (LV) and as a sensitive marker for ischemia. Unfortunately, there has previously been no way of measuring these noninvasively, severely limiting their research and clinical utility. Color Doppler M-mode (CMM) echocardiography provides a spatiotemporal velocity distribution along the inflow tract throughout diastole, which we hypothesized would allow direct estimation of IVPG by using the Euler equation. Digital CMM images, obtained simultaneously with intracardiac Pressure waveforms in six dogs, were processed by numerical differentiation for the Euler equation, then integrated to estimate IVPG and the total (left atrial to left ventricular apex) Pressure drop. CMM-derived estimates agreed well with invasive measurements (IVPG: y = 0.87x + 0.22, r = 0.96, P < 0.001, standard error of the estimate = 0.35 mmHg). Quantitative processing of CMM data allows accurate estimation of IVPG and tracking of changes induced by beta-adrenergic stimulation. This novel approach provides unique information on LV filling dynamics in an entirely noninvasive way that has previously not been available for assessment of diastolic filling and function.
H Frerichs - One of the best experts on this subject based on the ideXlab platform.
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the pattern of parallel edge plasma flows due to Pressure Gradients recycling and resonant magnetic perturbations in diii d
Physics of Plasmas, 2015Co-Authors: H Frerichs, O Schmitz, T E Evans, Y Feng, D ReiterAbstract:High resolution plasma transport simulations with the EMC3-EIRENE code have been performed to address the parallel plasma flow structure in the boundary of a poloidal divertor configuration with non-axisymmetric perturbations at DIII-D. Simulation results show that a checkerboard pattern of flows with alternating direction is generated inside the separatrix. This pattern is aligned with the position of the main resonances (i.e., where the safety factor is equal to rational values q=m/n for a perturbation field with base mode number n): m pairs of alternating forward and backward flow channel exist for each resonance. The poloidal oscillations are aligned with the subharmonic Melnikov function, which indicates that the plasma flow is generated by parallel Pressure Gradients along perturbed field lines. An additional scrape-off layer-like domain is introduced by the perturbed separatrix which guides field lines from the interior to the divertor targets, resulting in an enhanced outward flow that is consiste...
-
the pattern of parallel edge plasma flows due to Pressure Gradients recycling and resonant magnetic perturbations in diii d
Physics of Plasmas, 2015Co-Authors: H Frerichs, O Schmitz, T E Evans, Y Feng, D ReiterAbstract:High resolution plasma transport simulations with the EMC3-EIRENE code have been performed to address the parallel plasma flow structure in the boundary of a poloidal divertor configuration with non-axisymmetric perturbations at DIII-D. Simulation results show that a checkerboard pattern of flows with alternating direction is generated inside the separatrix. This pattern is aligned with the position of the main resonances (i.e., where the safety factor is equal to rational values q=m/n for a perturbation field with base mode number n): m pairs of alternating forward and backward flow channel exist for each resonance. The poloidal oscillations are aligned with the subharmonic Melnikov function, which indicates that the plasma flow is generated by parallel Pressure Gradients along perturbed field lines. An additional scrape-off layer-like domain is introduced by the perturbed separatrix which guides field lines from the interior to the divertor targets, resulting in an enhanced outward flow that is consistent with the experimentally observed particle pump-out effect. However, while the lobe structure of the perturbed separatrix is very well reflected in the temperature profile, the same lobes can appear to be smaller in the flow profile due to a competition between high upstream Pressure and downstream particle sources driving flows in opposite directions.
Neil L Greenberg - One of the best experts on this subject based on the ideXlab platform.
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relationship among diastolic intraventricular Pressure Gradients relaxation and preload impact of age and fitness
American Journal of Physiology-heart and Circulatory Physiology, 2006Co-Authors: Zoran B Popovic, Anand Prasad, Mario J Garcia, Armin Arbabzadeh, Allen G Borowski, Erika Dijk, Neil L Greenberg, Benjamin D Levine, James D ThomasAbstract:Diastolic intraventricular Pressure Gradients (IVPGs) are a measure of the ability of the ventricle to facilitate its filling using diastolic suction. We assessed 15 healthy young but sedentary sub...
-
relationship of diastolic intraventricular Pressure Gradients and aerobic capacity in patients with diastolic heart failure
American Journal of Physiology-heart and Circulatory Physiology, 2005Co-Authors: Aleksandr Rovner, James D Thomas, Neil L Greenberg, Mario J GarciaAbstract:We sought to elucidate the relationship between diastolic intraventricular Pressure Gradients (IVPG) and exercise tolerance in patients with heart failure using color M-mode Doppler. Diastolic dysf...
-
relationship between early diastolic intraventricular Pressure Gradients an index of elastic recoil and improvements in systolic and diastolic function
Circulation, 2001Co-Authors: Michael S Firstenberg, Mario J Garcia, Neil L Greenberg, Nicholas G Smedira, David L Prior, Patrick M Mccarthy, James D ThomasAbstract:Background Early diastolic intraventricular Pressure Gradients (IVPGs) have been proposed to relate to left ventricular (LV) elastic recoil and early ventricular “suction.” Animal studies have demo...
-
estimation of diastolic intraventricular Pressure Gradients by doppler m mode echocardiography
American Journal of Physiology-heart and Circulatory Physiology, 2001Co-Authors: Neil L Greenberg, Mario J Garcia, Michael S Firstenberg, Pieter M Vandervoort, James D ThomasAbstract:Previous studies have shown that small intraventricular Pressure Gradients (IVPG) are important for efficient filling of the left ventricle (LV) and as a sensitive marker for ischemia. Unfortunately, there has previously been no way of measuring these noninvasively, severely limiting their research and clinical utility. Color Doppler M-mode (CMM) echocardiography provides a spatiotemporal velocity distribution along the inflow tract throughout diastole, which we hypothesized would allow direct estimation of IVPG by using the Euler equation. Digital CMM images, obtained simultaneously with intracardiac Pressure waveforms in six dogs, were processed by numerical differentiation for the Euler equation, then integrated to estimate IVPG and the total (left atrial to left ventricular apex) Pressure drop. CMM-derived estimates agreed well with invasive measurements (IVPG: y = 0.87x + 0.22, r = 0.96, P < 0.001, standard error of the estimate = 0.35 mmHg). Quantitative processing of CMM data allows accurate estimation of IVPG and tracking of changes induced by beta-adrenergic stimulation. This novel approach provides unique information on LV filling dynamics in an entirely noninvasive way that has previously not been available for assessment of diastolic filling and function.
