Hydromagnetic flow between two porous disks rotating with same angular velocity Ω about two noncoincident axes has been studied in the presence of a uniform transverse magnetic field. An exact solution of the governi...Hydromagnetic flow between two porous disks rotating with same angular velocity Ω about two noncoincident axes has been studied in the presence of a uniform transverse magnetic field. An exact solution of the governing equations has been obtained in a closed form. It is found that the primary velocity f/Ωl increases and the secondary velocity g/Ωl decreases with increase in either Reynolds number Re or the Hartman number M. It is also found that the torque at the disk η= 0 increases with increase in either M^2 or K^2. On the other hand there is no torque at the disk η= 1 for large M^2 and K^2. The heat transfer characteristic has also been studied on taking viscous and Joule dissipation into account. It is seen that the temperature increases with increase in either M^2 or K^2. It is found that the rate of heat transfer at the disk η= 0 increases with increase in either M or K. On the other hand the rate of heat transfer at the disk η= 1 increases with increase in K but decreases with increase in M.展开更多
Atrial fibrillation(AF)is the most common form of cardiac arrhythmia,affecting 3 to 6 million people in the US,with an increased incidence in women and elderly,with its prevalence estimated to increase from 5.1 millio...Atrial fibrillation(AF)is the most common form of cardiac arrhythmia,affecting 3 to 6 million people in the US,with an increased incidence in women and elderly,with its prevalence estimated to increase from 5.1 million in 2000 to 15.9 million in 2050 in the US population.[1]Age,hypertension,heart failure,myocardial infarction(MI),genetic factors,and associated systemic inflammatory states are well-established risk factors for the development of AF.[2–6]Lifestyle factors including alcohol consumption,smoking,obesity,sedentary lifestyle,and vigorous physical activity have also been implicated to contribute to the development of AF.[2,7–9]Studies suggest that AF drives up medical expenditure.[10]The European Society of Cardiology,based on the duration,responsiveness to treatment,and therapeutic attitude of the patient and physician,classifies AF into 4 types;when AF occurs and terminates by itself or by intervention within 7 days of onset,it is called paroxysmal AF;if sustained for more than a week,with or without intervention.展开更多
In reference to the method of the Conference Board,the coincident indexes for China are constructed from a sample period between January 1990 and May 2012 and by51 chosen component indicators.The resulting coincident ...In reference to the method of the Conference Board,the coincident indexes for China are constructed from a sample period between January 1990 and May 2012 and by51 chosen component indicators.The resulting coincident indexes have higher correlations with gross domestic product(GDP) growth rates than the China Economic Monitoring and Analysis Center(CEMAC) coincident index over the sample period between February2005 and May 2012.The peaks and troughs of the growth rates in several indicators are identified.The total number of peaks and troughs in the resulting coincident index is the same with the CEMAC coincident index.Unfortunately,these troughs don't signify recessions in the Chinese economy because the financial system has not seen a negative growth rate over the specific sample periods.The impacts of the Southeast Asian Financial Crisis and subprime mortgage crisis on the business cycle could be dated via a smoother index from HP filtering to the coincident index.展开更多
Non-alcoholic fatty liver disease(NAFLD)is a global problem.It may be caused by metabolic and hormonal disorders,including hypothyroidism.However,non-thyroid causes of NAFLD in people with hypothyroidism,including imp...Non-alcoholic fatty liver disease(NAFLD)is a global problem.It may be caused by metabolic and hormonal disorders,including hypothyroidism.However,non-thyroid causes of NAFLD in people with hypothyroidism,including improper eating behavior and low physical activity,should be acknowledged.This study aimed to present the current literature on whether the development of NAFLD is related to hypothyroidism or a typical consequence of an unhealthy lifestyle in people with hypothyroidism.The results of previous studies do not allow for an unequivocal determination of the pathogenetic relationship between hypothyroidism and NAFLD.Important non-thyroid-initiating factors include providing too many calories in relation to requirements,consuming excessive amounts of monosaccharides and saturated fats,being overweight,and maintaining low physical activity levels.The recommended nutritional model for both hypothyroidism and NAFLD may be the Mediterranean diet,which is rich in fruits and vegetables,polyunsaturated fatty acids,and vitamin E.展开更多
Image quality in positron emission tomography(PET)is affected by random and scattered coincidences and reconstruction protocols.In this study,we investigated the effects of scattered and random coincidences from outsi...Image quality in positron emission tomography(PET)is affected by random and scattered coincidences and reconstruction protocols.In this study,we investigated the effects of scattered and random coincidences from outside the field of view(FOV)on PET image quality for different reconstruction protocols.Imaging was performed on the Discovery 690 PET/CT scanner,using experimental configurations including the NEMA phantom(a body phantom,with six spheres of different sizes)with a signal background ratio of 4:1.The NEMA phantom(phantom I)was scanned separately in a one-bed position.To simulate the effect of random and scatter coincidences from outside the FOV,six cylindrical phantoms with various diameters were added to the NEMA phantom(phantom II).The 18 emission datasets with mean intervals of 15 min were acquired(3 min/scan).The emission data were reconstructed using different techniques.The image quality parameters were evaluated by both phantoms.Variations in the signal-to-noise ratio(SNR)in a 28-mm(10-mm)sphere of phantom II were 37.9%(86.5%)for ordered-subset expectation maximization(OSEM-only),36.8%(81.5%)for point spread function(PSF),32.7%(80.7%)for time of flight(TOF),and 31.5%(77.8%)for OSEM+PSF+TOF,respectively,indicating that OSEM+PSF+TOF reconstruction had the lowest noise levels and lowest coefficient of variation(COV)values.Random and scatter coincidences from outside the FOV induced lower SNR,lower contrast,and higher COV values,indicating image deterioration and significantly impacting smaller sphere sizes.Amongst reconstruction protocols,OSEM+PSF+TOF and OSEM+PSF showed higher contrast values for sphere sizes of 22,28,and 37 mm and higher contrast recovery coefficient values for smaller sphere sizes of 10 and 13 mm.展开更多
Hydrodynamic viscous incompressible fluid flow through a porous medium between two disks rotating with same angular velocity about two non-coincident axes has been studied. An exact solution of the govern-ing equation...Hydrodynamic viscous incompressible fluid flow through a porous medium between two disks rotating with same angular velocity about two non-coincident axes has been studied. An exact solution of the govern-ing equations has been obtained in a closed form. It is found that the primary velocity decreases and the sec-ondary velocity increases with increase in porosity parameter to the left of the z-axis and the result is re-versed to the right of the z-axis. It is also found that the torque on the disks increases with increase in either rotation parameter or porosity parameter. For large rotation, there exist a thin boundary layer near the disks and the thickness of this boundary layer decreases with increase in porosity parameter.展开更多
基金University Grants Commissions for financial provision
文摘Hydromagnetic flow between two porous disks rotating with same angular velocity Ω about two noncoincident axes has been studied in the presence of a uniform transverse magnetic field. An exact solution of the governing equations has been obtained in a closed form. It is found that the primary velocity f/Ωl increases and the secondary velocity g/Ωl decreases with increase in either Reynolds number Re or the Hartman number M. It is also found that the torque at the disk η= 0 increases with increase in either M^2 or K^2. On the other hand there is no torque at the disk η= 1 for large M^2 and K^2. The heat transfer characteristic has also been studied on taking viscous and Joule dissipation into account. It is seen that the temperature increases with increase in either M^2 or K^2. It is found that the rate of heat transfer at the disk η= 0 increases with increase in either M or K. On the other hand the rate of heat transfer at the disk η= 1 increases with increase in K but decreases with increase in M.
文摘Atrial fibrillation(AF)is the most common form of cardiac arrhythmia,affecting 3 to 6 million people in the US,with an increased incidence in women and elderly,with its prevalence estimated to increase from 5.1 million in 2000 to 15.9 million in 2050 in the US population.[1]Age,hypertension,heart failure,myocardial infarction(MI),genetic factors,and associated systemic inflammatory states are well-established risk factors for the development of AF.[2–6]Lifestyle factors including alcohol consumption,smoking,obesity,sedentary lifestyle,and vigorous physical activity have also been implicated to contribute to the development of AF.[2,7–9]Studies suggest that AF drives up medical expenditure.[10]The European Society of Cardiology,based on the duration,responsiveness to treatment,and therapeutic attitude of the patient and physician,classifies AF into 4 types;when AF occurs and terminates by itself or by intervention within 7 days of onset,it is called paroxysmal AF;if sustained for more than a week,with or without intervention.
基金the support provided by Ford Foundation,Stanford SCID and National Planning Office of Philosophy and Social Science(Approval No.12 & ZD038)
文摘In reference to the method of the Conference Board,the coincident indexes for China are constructed from a sample period between January 1990 and May 2012 and by51 chosen component indicators.The resulting coincident indexes have higher correlations with gross domestic product(GDP) growth rates than the China Economic Monitoring and Analysis Center(CEMAC) coincident index over the sample period between February2005 and May 2012.The peaks and troughs of the growth rates in several indicators are identified.The total number of peaks and troughs in the resulting coincident index is the same with the CEMAC coincident index.Unfortunately,these troughs don't signify recessions in the Chinese economy because the financial system has not seen a negative growth rate over the specific sample periods.The impacts of the Southeast Asian Financial Crisis and subprime mortgage crisis on the business cycle could be dated via a smoother index from HP filtering to the coincident index.
文摘Non-alcoholic fatty liver disease(NAFLD)is a global problem.It may be caused by metabolic and hormonal disorders,including hypothyroidism.However,non-thyroid causes of NAFLD in people with hypothyroidism,including improper eating behavior and low physical activity,should be acknowledged.This study aimed to present the current literature on whether the development of NAFLD is related to hypothyroidism or a typical consequence of an unhealthy lifestyle in people with hypothyroidism.The results of previous studies do not allow for an unequivocal determination of the pathogenetic relationship between hypothyroidism and NAFLD.Important non-thyroid-initiating factors include providing too many calories in relation to requirements,consuming excessive amounts of monosaccharides and saturated fats,being overweight,and maintaining low physical activity levels.The recommended nutritional model for both hypothyroidism and NAFLD may be the Mediterranean diet,which is rich in fruits and vegetables,polyunsaturated fatty acids,and vitamin E.
基金supported by the Tehran University of Medical Sciences under Grant No.36291PET/CT and Cyclotron Center of Masih Daneshvari Hospital at Shahid Beheshti University of Medical Sciences。
文摘Image quality in positron emission tomography(PET)is affected by random and scattered coincidences and reconstruction protocols.In this study,we investigated the effects of scattered and random coincidences from outside the field of view(FOV)on PET image quality for different reconstruction protocols.Imaging was performed on the Discovery 690 PET/CT scanner,using experimental configurations including the NEMA phantom(a body phantom,with six spheres of different sizes)with a signal background ratio of 4:1.The NEMA phantom(phantom I)was scanned separately in a one-bed position.To simulate the effect of random and scatter coincidences from outside the FOV,six cylindrical phantoms with various diameters were added to the NEMA phantom(phantom II).The 18 emission datasets with mean intervals of 15 min were acquired(3 min/scan).The emission data were reconstructed using different techniques.The image quality parameters were evaluated by both phantoms.Variations in the signal-to-noise ratio(SNR)in a 28-mm(10-mm)sphere of phantom II were 37.9%(86.5%)for ordered-subset expectation maximization(OSEM-only),36.8%(81.5%)for point spread function(PSF),32.7%(80.7%)for time of flight(TOF),and 31.5%(77.8%)for OSEM+PSF+TOF,respectively,indicating that OSEM+PSF+TOF reconstruction had the lowest noise levels and lowest coefficient of variation(COV)values.Random and scatter coincidences from outside the FOV induced lower SNR,lower contrast,and higher COV values,indicating image deterioration and significantly impacting smaller sphere sizes.Amongst reconstruction protocols,OSEM+PSF+TOF and OSEM+PSF showed higher contrast values for sphere sizes of 22,28,and 37 mm and higher contrast recovery coefficient values for smaller sphere sizes of 10 and 13 mm.
文摘Hydrodynamic viscous incompressible fluid flow through a porous medium between two disks rotating with same angular velocity about two non-coincident axes has been studied. An exact solution of the govern-ing equations has been obtained in a closed form. It is found that the primary velocity decreases and the sec-ondary velocity increases with increase in porosity parameter to the left of the z-axis and the result is re-versed to the right of the z-axis. It is also found that the torque on the disks increases with increase in either rotation parameter or porosity parameter. For large rotation, there exist a thin boundary layer near the disks and the thickness of this boundary layer decreases with increase in porosity parameter.
