Biofuels produced from cellulosic biomass can be used to replace petroleum-based transportation fuels. However, the manufacturing cost of cellulosic biofuels is still high, partly due to the low density of cellulosic ...Biofuels produced from cellulosic biomass can be used to replace petroleum-based transportation fuels. However, the manufacturing cost of cellulosic biofuels is still high, partly due to the low density of cellulosic feed-stocks. Pelleting of cellulosic feedstocks can increase their density, making their transportation and storage as well as biofuel conversion more efficient and, therefore, reducing the overall cost of biofuel manufacturing. It has been shown that ultrasonic-vibration-assisted (UV-A) pelleting, without using high-temperature steam and binder materials, can produce pellets with density comparable to that produced by conventional pelleting methods. Furthermore, the sugar yield of biomass (wheat straw) processed with UV-A pelleting is 20% higher than that of biomass pelleted without ultrasonic vibration. This paper reports an experimental investigation of UV-A pelleting of switchgrass. The influences of ultrasonic vibration on pellet density, stability, durability, and pelleting force are discussed. It is concluded that pellets processed with ultrasonic vibration had higher density and stability than those processed without ultrasonic vibration, they were more durable than those processed without ultrasonic vibration, and pelleting force with ultrasonic vibration was lower than that without ultrasonic vibration.展开更多
Objective : to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. Methods : The study population consisted of 9 patients with 5 males and 4 fem...Objective : to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. Methods : The study population consisted of 9 patients with 5 males and 4 females enrolled consecutively who had idiopathic paroxysmal atrial fibrillation(AF) . The ultrasound balloon was positioned through a special sheath to the orifice of the target vein by a transseptal procedure. The balloon was inflated with contrast-mixed saline (contrast: saline = 1:4) whose volume was decided by the diameter of the target pulmonary vein. The ablation energy was usually set up at 35 to 40 watts with temperature controlled at 60℃ . The duration of each ablation was about 120 seconds which was repeated not over 10 times. Results: The average duration of the total procedure was 132± 68 min for our patients. The average fluoroscopy time was 33 ±17 min. With a mean follow-up of 16 ±8 months after the procedure, AF was completely eliminated in 4 patients without antiarrhythmic drugs. The episodes of atrial fibrillation were eliminated in 2 patients with low dosage of oral amiodarone (0.1, once daily) which was ineffective before the procedure. The frequency of episodes was similar to that before the procedure in 3 patients. There were no complications such as hemopericardium, air embolism and stenosis of the pulmonary veins by angiography, related to the procedure. Conclusion : Ultrasound ablation of the pulmonary veins is a new approach to treat paroxysmal atrial fibrillation. Before we determined its value, we need to do more researches with bigger sample, randomization and comparison design.展开更多
Objective To evaluate the transesophageal echocardiography(TEE) and surgical treatment to cardiac papillary fibroelastomas (CPFE). Methods CPFE is a rare benign tumor occuring mainly in valves and often revealed by se...Objective To evaluate the transesophageal echocardiography(TEE) and surgical treatment to cardiac papillary fibroelastomas (CPFE). Methods CPFE is a rare benign tumor occuring mainly in valves and often revealed by serious cerebral, coronary and peripheral embolism or even sudden death. We report a case of mitral PFE diagnosed by transesophageal echocardiography (TEE), and surgical resection was performed. Results Surgical intervention is successful, and the follow-up courses are uneventful. Conclusion TEE is helpful to diagnosis and guiding the operation. Operation is recommended to prevent recurrent embolization complications.展开更多
基金Supported by National Science Foundation of USA(CMMI-0970112)
文摘Biofuels produced from cellulosic biomass can be used to replace petroleum-based transportation fuels. However, the manufacturing cost of cellulosic biofuels is still high, partly due to the low density of cellulosic feed-stocks. Pelleting of cellulosic feedstocks can increase their density, making their transportation and storage as well as biofuel conversion more efficient and, therefore, reducing the overall cost of biofuel manufacturing. It has been shown that ultrasonic-vibration-assisted (UV-A) pelleting, without using high-temperature steam and binder materials, can produce pellets with density comparable to that produced by conventional pelleting methods. Furthermore, the sugar yield of biomass (wheat straw) processed with UV-A pelleting is 20% higher than that of biomass pelleted without ultrasonic vibration. This paper reports an experimental investigation of UV-A pelleting of switchgrass. The influences of ultrasonic vibration on pellet density, stability, durability, and pelleting force are discussed. It is concluded that pellets processed with ultrasonic vibration had higher density and stability than those processed without ultrasonic vibration, they were more durable than those processed without ultrasonic vibration, and pelleting force with ultrasonic vibration was lower than that without ultrasonic vibration.
文摘Objective : to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. Methods : The study population consisted of 9 patients with 5 males and 4 females enrolled consecutively who had idiopathic paroxysmal atrial fibrillation(AF) . The ultrasound balloon was positioned through a special sheath to the orifice of the target vein by a transseptal procedure. The balloon was inflated with contrast-mixed saline (contrast: saline = 1:4) whose volume was decided by the diameter of the target pulmonary vein. The ablation energy was usually set up at 35 to 40 watts with temperature controlled at 60℃ . The duration of each ablation was about 120 seconds which was repeated not over 10 times. Results: The average duration of the total procedure was 132± 68 min for our patients. The average fluoroscopy time was 33 ±17 min. With a mean follow-up of 16 ±8 months after the procedure, AF was completely eliminated in 4 patients without antiarrhythmic drugs. The episodes of atrial fibrillation were eliminated in 2 patients with low dosage of oral amiodarone (0.1, once daily) which was ineffective before the procedure. The frequency of episodes was similar to that before the procedure in 3 patients. There were no complications such as hemopericardium, air embolism and stenosis of the pulmonary veins by angiography, related to the procedure. Conclusion : Ultrasound ablation of the pulmonary veins is a new approach to treat paroxysmal atrial fibrillation. Before we determined its value, we need to do more researches with bigger sample, randomization and comparison design.
文摘Objective To evaluate the transesophageal echocardiography(TEE) and surgical treatment to cardiac papillary fibroelastomas (CPFE). Methods CPFE is a rare benign tumor occuring mainly in valves and often revealed by serious cerebral, coronary and peripheral embolism or even sudden death. We report a case of mitral PFE diagnosed by transesophageal echocardiography (TEE), and surgical resection was performed. Results Surgical intervention is successful, and the follow-up courses are uneventful. Conclusion TEE is helpful to diagnosis and guiding the operation. Operation is recommended to prevent recurrent embolization complications.
