Journal of Cardiovascular Electrophysiology, Jul 20, 2023
IntroductionWe describe a unique case of TECRL‐CPVT presented with cardiac arrest.MethodsPost res... more IntroductionWe describe a unique case of TECRL‐CPVT presented with cardiac arrest.MethodsPost resuscitation, the patient developed regular ventricular tachycardia featuring a left purkinje system morphology.ResultsThere was clear suppression of arrhythmia with the addition of flecainide and isolated ventricular ectopy causing secondary T‐wave changes.ConclusionA high index of suspicion was required to eventually make the diagnosis through whole exome sequencing.
Objectives: This study assesses the competency of pediatricians in interpreting electrocardiogram... more Objectives: This study assesses the competency of pediatricians in interpreting electrocardiograms (ECGs). Methods: A cross-sectional study involving 125 pediatricians comprised of 71 general pediatricians, 15 pediatric cardiologists, and 39 other subspecialists recruited from all public hospitals and two specialty centers. Participants completed a questionnaire that included 10 ECGs and questions regarding backgrounds, attitudes, and practices. The ECGs were graded to obtain a knowledge score out of 30 points. Mann–Whitney U test and Kruskal-Wallis test with post hoc analysis and Bonferroni adjustment were used to compare groups. Results: The mean knowledge score ranged from 47.7% to 69.7% among various pediatric specialties (P = 0.006). Age, increasing years of experience, confidence level, number of cardiology referrals, and perceived importance of having good ECG interpretation skills were significantly related to the knowledge score (P = 0.05). Accuracy was highest in identifying normal ECGs (76.8%), supraventricular tachycardia (64.8%), along with long QT interval (58.4%), and was lowest for right bundle branch block (RBBB) (10.4%), 2:1 atrioventricular conduction (10.4%), and atrial tachycardia (AT) (4.8%). Accuracy among pediatric cardiologists was highest for long QT interval (100%), normal ECG (80%), as well as Wolff-Parkinson-White syndrome (80%), and lowest for RBBB (13.3%) and AT (0%). Most pediatricians believe that ECGs are “useful” (78.4%) and that having good interpretation skill is “important” (80.6%). Conclusions: Pediatricians recognize the importance of ECGs. However, their skill and level of accuracy at interpretation is suboptimal, including cardiologists, and may affect patient care. Thus, efforts should be made to improve ECG understanding to provide better service to patients.
Fracture causes enormous material and energy waste per annum, with large economical, industrial a... more Fracture causes enormous material and energy waste per annum, with large economical, industrial and environmental impact. In particular, ductile failure under shear-dominated loading pervades in many areas of manufacturing, load-bearing structures and impact protection systems. However, failure in shear remain elusive there being no complete theory of ductile fracture without a physics-based model. A robust micromechanics-based constitutive framework, founded on mechanism-based yield criteria for materials with evolution laws accounting for microstructural evolution, is essential to this end. Experimental observations reveal cell-level plastic deformation as homogeneous or inhomogeneous, the latter being idealized with plasticity confined within intervoid ligaments or occasionally within intervoid plugs. The present thesis is partly targeted to the development of analytical yield functions that predict yielding by either mechanism, attained by limit analysis over a cylindrical cell containing a coaxial void. Nonetheless, existing outcomes indicate the shear-dominated deformation process at early stages as an intermediate state between a homogeneous and an ideally localized one. Correspondingly, a hybrid model is adopted consisting of simple modifications to both an existing homogeneous yield criterion as well as a derived localized yield function. Upon current limitations of a highly complex physical process, a surrogate microstructure, tied to a possible localization plane, is invoked. The next missing link to the constitutive framework calls for microstructural evolution equations during localized deformation, which sets the second objective of the present work. The body of existing and derived yield criteria supplemented with available and derived evolution equations sets enough grounds for the numerical simulation of ductile fracture, thus the third milestone. The hybrid model predictions are firstly borne out by existing numerical outcomes under combined loading. The parametric studies are then carried through a complete range of loading combinations from uniaxial to pure shear loading. The effects of initial porosity, void shape, relative spacing, void misalignment with the principal loading directions, and matrix plastic anisotropy are accounted for. Furthermore, the strain to failure is evaluated vs. a complete scope of triaxialities. The thesis closes with proposed extensions to 3D voids, void coalescence along columns and other potential prospects for more robust numerical implementation. Key Words: Ductile fracture; Void coalescence; Combined tension and shear; Homogeneous/ Inhomogeneous Yielding; Strain localization; Simple/Pure shear
Abstract Total anomalous pulmonary venous drainage (TAPVD) is a rare congenital anomaly associate... more Abstract Total anomalous pulmonary venous drainage (TAPVD) is a rare congenital anomaly associated with a high mortality rate, especially when associated with complex congenital heart disease (CHD). This is a retrospective study, conducted between 2011 and 2020, aiming to document outcomes and identify predictors for mortality. A total of forty-three patients underwent repair. The mean follow-up time was 4.6 years (±2.3). Thirty-five patients had isolated disease while 8 patients had complex TAPVD, 4 of which had single ventricle (SV) physiology. Pre- and postoperative pulmonary venous obstruction (PVO) were documented at 28% and 21%, respectively. The overall mortality rate was at 14% and highly associated with the SV group (p
As one of the arid areas of Iran, Yazd is always exposed to extreme winds with dust and shifting ... more As one of the arid areas of Iran, Yazd is always exposed to extreme winds with dust and shifting sands. Therefore, the architectural principles in the residential architecture of the city need be adapted to such environmental conditions in order to minimize the influence of the severe winds on the interior spaces. This study investigates the influence of storms on the interior space of the central courtyards in Yazd, constructed during the Muzaffarid, Safavid and Qajar periods using CFD simulation. Three-dimensional models were prepared via Gambit software and studied in Fluent software. The wind speed entering the computing field was equal to 26.4m/s and the Dutch wind nuisance standard NEN 8100 was applied as the comfort criterion. The results showed a relationship between the extent of the central courtyard and the impact of severe storms on it, since an increase in the area of the courtyard provides enough space for the wind flow and move around it. This feature reaches its clim...
Industrial & Engineering Chemistry Research, 2014
In this work, the experimental investigation of SO2 removal reaction by CuO was accomplished in a... more In this work, the experimental investigation of SO2 removal reaction by CuO was accomplished in a packed bed reactor between 400 and 600 °C at 1250–5000 ppm of inlet SO2. Moreover, the mathematical modeling of this reaction was performed by the random pore model. The partial differential equations in a packed bed reactor were solved using finite element technique. The kinetic parameters were previously determined from thermogravimetry tests on a single-pellet CuO reaction with SO2 at various concentrations and temperatures. The results of modeling consist of packed bed breakthrough curves at different temperatures and SO2 concentrations, which were compared with the experimental results successfully. By increasing the reactor temperature from 400 to 600 °C, the appearance of the breakthrough curve shifts from 200 to 550 min. Similarly, by decreasing the inlet SO2 concentration from 5000 to 1250 ppm, the breakthrough profile appears at 900 min instead of 200 min.
Journal of Cardiovascular Electrophysiology, Jul 20, 2023
IntroductionWe describe a unique case of TECRL‐CPVT presented with cardiac arrest.MethodsPost res... more IntroductionWe describe a unique case of TECRL‐CPVT presented with cardiac arrest.MethodsPost resuscitation, the patient developed regular ventricular tachycardia featuring a left purkinje system morphology.ResultsThere was clear suppression of arrhythmia with the addition of flecainide and isolated ventricular ectopy causing secondary T‐wave changes.ConclusionA high index of suspicion was required to eventually make the diagnosis through whole exome sequencing.
Objectives: This study assesses the competency of pediatricians in interpreting electrocardiogram... more Objectives: This study assesses the competency of pediatricians in interpreting electrocardiograms (ECGs). Methods: A cross-sectional study involving 125 pediatricians comprised of 71 general pediatricians, 15 pediatric cardiologists, and 39 other subspecialists recruited from all public hospitals and two specialty centers. Participants completed a questionnaire that included 10 ECGs and questions regarding backgrounds, attitudes, and practices. The ECGs were graded to obtain a knowledge score out of 30 points. Mann–Whitney U test and Kruskal-Wallis test with post hoc analysis and Bonferroni adjustment were used to compare groups. Results: The mean knowledge score ranged from 47.7% to 69.7% among various pediatric specialties (P = 0.006). Age, increasing years of experience, confidence level, number of cardiology referrals, and perceived importance of having good ECG interpretation skills were significantly related to the knowledge score (P = 0.05). Accuracy was highest in identifying normal ECGs (76.8%), supraventricular tachycardia (64.8%), along with long QT interval (58.4%), and was lowest for right bundle branch block (RBBB) (10.4%), 2:1 atrioventricular conduction (10.4%), and atrial tachycardia (AT) (4.8%). Accuracy among pediatric cardiologists was highest for long QT interval (100%), normal ECG (80%), as well as Wolff-Parkinson-White syndrome (80%), and lowest for RBBB (13.3%) and AT (0%). Most pediatricians believe that ECGs are “useful” (78.4%) and that having good interpretation skill is “important” (80.6%). Conclusions: Pediatricians recognize the importance of ECGs. However, their skill and level of accuracy at interpretation is suboptimal, including cardiologists, and may affect patient care. Thus, efforts should be made to improve ECG understanding to provide better service to patients.
Fracture causes enormous material and energy waste per annum, with large economical, industrial a... more Fracture causes enormous material and energy waste per annum, with large economical, industrial and environmental impact. In particular, ductile failure under shear-dominated loading pervades in many areas of manufacturing, load-bearing structures and impact protection systems. However, failure in shear remain elusive there being no complete theory of ductile fracture without a physics-based model. A robust micromechanics-based constitutive framework, founded on mechanism-based yield criteria for materials with evolution laws accounting for microstructural evolution, is essential to this end. Experimental observations reveal cell-level plastic deformation as homogeneous or inhomogeneous, the latter being idealized with plasticity confined within intervoid ligaments or occasionally within intervoid plugs. The present thesis is partly targeted to the development of analytical yield functions that predict yielding by either mechanism, attained by limit analysis over a cylindrical cell containing a coaxial void. Nonetheless, existing outcomes indicate the shear-dominated deformation process at early stages as an intermediate state between a homogeneous and an ideally localized one. Correspondingly, a hybrid model is adopted consisting of simple modifications to both an existing homogeneous yield criterion as well as a derived localized yield function. Upon current limitations of a highly complex physical process, a surrogate microstructure, tied to a possible localization plane, is invoked. The next missing link to the constitutive framework calls for microstructural evolution equations during localized deformation, which sets the second objective of the present work. The body of existing and derived yield criteria supplemented with available and derived evolution equations sets enough grounds for the numerical simulation of ductile fracture, thus the third milestone. The hybrid model predictions are firstly borne out by existing numerical outcomes under combined loading. The parametric studies are then carried through a complete range of loading combinations from uniaxial to pure shear loading. The effects of initial porosity, void shape, relative spacing, void misalignment with the principal loading directions, and matrix plastic anisotropy are accounted for. Furthermore, the strain to failure is evaluated vs. a complete scope of triaxialities. The thesis closes with proposed extensions to 3D voids, void coalescence along columns and other potential prospects for more robust numerical implementation. Key Words: Ductile fracture; Void coalescence; Combined tension and shear; Homogeneous/ Inhomogeneous Yielding; Strain localization; Simple/Pure shear
Abstract Total anomalous pulmonary venous drainage (TAPVD) is a rare congenital anomaly associate... more Abstract Total anomalous pulmonary venous drainage (TAPVD) is a rare congenital anomaly associated with a high mortality rate, especially when associated with complex congenital heart disease (CHD). This is a retrospective study, conducted between 2011 and 2020, aiming to document outcomes and identify predictors for mortality. A total of forty-three patients underwent repair. The mean follow-up time was 4.6 years (±2.3). Thirty-five patients had isolated disease while 8 patients had complex TAPVD, 4 of which had single ventricle (SV) physiology. Pre- and postoperative pulmonary venous obstruction (PVO) were documented at 28% and 21%, respectively. The overall mortality rate was at 14% and highly associated with the SV group (p
As one of the arid areas of Iran, Yazd is always exposed to extreme winds with dust and shifting ... more As one of the arid areas of Iran, Yazd is always exposed to extreme winds with dust and shifting sands. Therefore, the architectural principles in the residential architecture of the city need be adapted to such environmental conditions in order to minimize the influence of the severe winds on the interior spaces. This study investigates the influence of storms on the interior space of the central courtyards in Yazd, constructed during the Muzaffarid, Safavid and Qajar periods using CFD simulation. Three-dimensional models were prepared via Gambit software and studied in Fluent software. The wind speed entering the computing field was equal to 26.4m/s and the Dutch wind nuisance standard NEN 8100 was applied as the comfort criterion. The results showed a relationship between the extent of the central courtyard and the impact of severe storms on it, since an increase in the area of the courtyard provides enough space for the wind flow and move around it. This feature reaches its clim...
Industrial & Engineering Chemistry Research, 2014
In this work, the experimental investigation of SO2 removal reaction by CuO was accomplished in a... more In this work, the experimental investigation of SO2 removal reaction by CuO was accomplished in a packed bed reactor between 400 and 600 °C at 1250–5000 ppm of inlet SO2. Moreover, the mathematical modeling of this reaction was performed by the random pore model. The partial differential equations in a packed bed reactor were solved using finite element technique. The kinetic parameters were previously determined from thermogravimetry tests on a single-pellet CuO reaction with SO2 at various concentrations and temperatures. The results of modeling consist of packed bed breakthrough curves at different temperatures and SO2 concentrations, which were compared with the experimental results successfully. By increasing the reactor temperature from 400 to 600 °C, the appearance of the breakthrough curve shifts from 200 to 550 min. Similarly, by decreasing the inlet SO2 concentration from 5000 to 1250 ppm, the breakthrough profile appears at 900 min instead of 200 min.
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Papers by Mohammad Ebrahim