The Experts below are selected from a list of 23316 Experts worldwide ranked by ideXlab platform
William J. Powers - One of the best experts on this subject based on the ideXlab platform.
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cerebral oxygen extraction fraction in carotid occlusive disease measurement and clinical significance
Reference Module in Neuroscience and Biobehavioral Psychology#R##N#Brain Mapping#R##N#An Encyclopedic Reference, 2015Co-Authors: William J. PowersAbstract:In patients with carotid or middle cerebral artery occlusive disease, the cerebral blood Flow downstream from the arterial obstruction will depend on the adequacy of the collateral circulation. Oxygen extraction fraction (OEF) will increase as a compensatory response to maintain cerebral oxygen metabolism when the collateral pathways are inSufficient to maintain CBF at a normal level but still adequate to Provide Sufficient Flow to prevent cerebral infarction. Positron emission tomography permits the measurement of regional OEF in humans and can identify patients with symptomatic carotid or middle cerebral artery occlusive disease who are at high risk for subsequent stroke. Extracranial–intracranial bypass surgery can improve CBF distal to the obstruction return, OEF toward normal, and reduce the risk of stroke over the subsequent 2 years. However, the perioperative stroke rate is Sufficient to nullify any overall benefit of surgery.
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cerebral oxygen extraction fraction in carotid occlusive disease measurement and clinical significance
Reference Module in Neuroscience and Biobehavioral Psychology#R##N#Brain Mapping#R##N#An Encyclopedic Reference, 2015Co-Authors: William J. PowersAbstract:In patients with carotid or middle cerebral artery occlusive disease, the cerebral blood Flow downstream from the arterial obstruction will depend on the adequacy of the collateral circulation. Oxygen extraction fraction (OEF) will increase as a compensatory response to maintain cerebral oxygen metabolism when the collateral pathways are inSufficient to maintain CBF at a normal level but still adequate to Provide Sufficient Flow to prevent cerebral infarction. Positron emission tomography permits the measurement of regional OEF in humans and can identify patients with symptomatic carotid or middle cerebral artery occlusive disease who are at high risk for subsequent stroke. Extracranial–intracranial bypass surgery can improve CBF distal to the obstruction return, OEF toward normal, and reduce the risk of stroke over the subsequent 2 years. However, the perioperative stroke rate is Sufficient to nullify any overall benefit of surgery.
Zongan Liang - One of the best experts on this subject based on the ideXlab platform.
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Comparison of Actual Performance in the Flow and Fraction of Inspired O2 among Different High-Flow Nasal Cannula Devices: A Bench Study
'Hindawi Limited', 2021Co-Authors: Yuyan Zhou, Binmiao Liang, Zongan LiangAbstract:Background. High-Flow nasal cannula (HFNC) oxygen therapy has been recommended for use in coronavirus disease 2019 (COVID-19) patients with acute respiratory failure and many other clinical conditions. HFNC devices produced by different manufacturers may have varied performance. Whether there is a difference in these devices and the extent of the differences in performance remain unknown. Methods. Four HFNC devices (AIRVO 2, TNI softFlow 50, HUMID-BH, and OH-70C) and a ventilator with an HFNC module (bellavista 1000) were evaluated. The Flow was set at 20, 25, 30, 35, 40, 45, 50, 60, 70, and 80 L/min, and the FiO2 was set at 21%, 26%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, and 90%. Then, one side of the cannulas was clipped to simulate the compression, bending, or blocking of the nasal cannulas. The Flow and FiO2 of the delivered gas were recorded and compared among settings and devices. Results. The actual-Flow and actual-FiO2 delivered by different settings and devices varied. AIRVO 2 had superior performance in Flow and FiO2 accuracy. bellavista 1000 and OH-70C had good performance in the accuracy of actual-Flows and actual-FiO2, respectively. bellavista 1000 and HUMID-BH had a larger Flow range from 10 to 80 L/min, but only bellavista 1000 could Provide a stable Flow with an excessive resistance up to 60 L/min. TNI softFlow 50 had the best Flow compensation and could Provide Sufficient Flow with excessive resistance at 20–50 L/min. Conclusions. The variation in Flow, FiO2 settings, and devices could influence the actual-Flow and actual-FiO2 delivered. AIRVO 2 and OH-70C showed better FiO2 accuracy. TNI softFlow 50, bellavista 1000, and HUMID-BH could lower the risk of inSufficient Flow support due to accidental compression or blocking of the cannulas. In addition, ventilators with HFNC modules Provided comparable Flow and FiO2 and could be an alternative to standalone HFNC devices
Takakazu Kawamata - One of the best experts on this subject based on the ideXlab platform.
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novel surgical management of spinal adhesive arachnoiditis by arachnoid microdissection and ventriculo subarachnoid shunting
Journal of Clinical Neuroscience, 2011Co-Authors: Tetsuryu Mitsuyama, Shunji Asamoto, Takakazu KawamataAbstract:Spinal cord tethering and cerebrospinal fluid (CSF) Flow disturbance are two major features in the pathophysiology of spinal adhesive arachnoiditis. We hypothesized that inSufficient CSF supply to the surgically untethered spinal cord may be one of the causes of the typical post-operative recurrent extensive lesion. We report a patient with extensive spinal adhesive arachnoiditis, who was successfully treated using a novel surgical technique consisting of two procedures. First, microdissection of the thickened adherent arachnoid was performed to resolve spinal cord tethering. Next, a ventriculo-subarachnoid shunt was placed to Provide Sufficient Flow of CSF. Clinical improvement was sustained for at least 22 months after surgery. The present surgical procedure may improve clinical outcome in patients with longitudinally extensive spinal adhesive arachnoiditis.
Lingyu Meng - One of the best experts on this subject based on the ideXlab platform.
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electro hydraulic position control system via active disturbance rejection controller supplied with oil by variable pressure accumulators
International Conference on Fluid Power and Mechatronics, 2019Co-Authors: Dingxuan Zhao, Fanliang Meng, Lixin Wang, Lingyu MengAbstract:In some special hydraulic position control systems, the actuator is required to operate at a high speed in a short time. In order to reduce the installed power of the hydraulic pump station, the accumulator can be used as the auxiliary power source to Provide Sufficient Flow for the actuator in a short time. However, due to factors such as accumulator oil supply pressure variation, hydraulic system nonlinearity, and disturbance of load and frictional resistance, position control of the system is more difficult. Aiming at this problem, this paper designs a nonlinear active disturbance rejection control (NLADRC) strategy based on the mathematical model of electro-hydraulic position control system with energy accumulator as power source, this controller estimates the system internal and external disturbances by nonlinear extended state observer (NLESO) in real time and the disturbance is compensated actively by nonlinear error feedback controller (NLSEF). Finally, the control method is verified through the joint simulation of MATLAB and AMESim. The simulation results show that compared with the PID controller, the NLADRC strategy effectively suppresses the internal and external disturbance of the system, reduces the adverse effect caused by the variable pressure oil supply of the accumulator, improves the position control accuracy of the system, improves the system static and dynamic control effect and verifies the effectiveness and superiority of the NLADRC strategy.
Yuyan Zhou - One of the best experts on this subject based on the ideXlab platform.
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Comparison of Actual Performance in the Flow and Fraction of Inspired O2 among Different High-Flow Nasal Cannula Devices: A Bench Study
'Hindawi Limited', 2021Co-Authors: Yuyan Zhou, Binmiao Liang, Zongan LiangAbstract:Background. High-Flow nasal cannula (HFNC) oxygen therapy has been recommended for use in coronavirus disease 2019 (COVID-19) patients with acute respiratory failure and many other clinical conditions. HFNC devices produced by different manufacturers may have varied performance. Whether there is a difference in these devices and the extent of the differences in performance remain unknown. Methods. Four HFNC devices (AIRVO 2, TNI softFlow 50, HUMID-BH, and OH-70C) and a ventilator with an HFNC module (bellavista 1000) were evaluated. The Flow was set at 20, 25, 30, 35, 40, 45, 50, 60, 70, and 80 L/min, and the FiO2 was set at 21%, 26%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, and 90%. Then, one side of the cannulas was clipped to simulate the compression, bending, or blocking of the nasal cannulas. The Flow and FiO2 of the delivered gas were recorded and compared among settings and devices. Results. The actual-Flow and actual-FiO2 delivered by different settings and devices varied. AIRVO 2 had superior performance in Flow and FiO2 accuracy. bellavista 1000 and OH-70C had good performance in the accuracy of actual-Flows and actual-FiO2, respectively. bellavista 1000 and HUMID-BH had a larger Flow range from 10 to 80 L/min, but only bellavista 1000 could Provide a stable Flow with an excessive resistance up to 60 L/min. TNI softFlow 50 had the best Flow compensation and could Provide Sufficient Flow with excessive resistance at 20–50 L/min. Conclusions. The variation in Flow, FiO2 settings, and devices could influence the actual-Flow and actual-FiO2 delivered. AIRVO 2 and OH-70C showed better FiO2 accuracy. TNI softFlow 50, bellavista 1000, and HUMID-BH could lower the risk of inSufficient Flow support due to accidental compression or blocking of the cannulas. In addition, ventilators with HFNC modules Provided comparable Flow and FiO2 and could be an alternative to standalone HFNC devices
