Aortic stenosis is the most common native valve disease, affecting up to 5% of the elderly population. Surgical aortic valve replacement reduces symptoms and improves survival, and is the definitive therapy in patient...Aortic stenosis is the most common native valve disease, affecting up to 5% of the elderly population. Surgical aortic valve replacement reduces symptoms and improves survival, and is the definitive therapy in patients with symptomatic severe aortic stenosis. However, despite the good results of classic surgery, risk is markedly increased in elderly patients with co-morbidities. Transcatheter aortic valve replacement （TAVR） allows implantation of a prosthetic heart valve within the diseased native aortic valve without the need for open heart surgery and cardiopulmonary bypass, offering a new therapeutic option to elderly patients considered at high surgical risk or with contraindications to surgery. To date, several multicenter registries and a randomized trial have confirmed the safety and efficacy of TAVR in those patients. In this chapter, we review the background and clinical applications of TAVR in elderly patients.展开更多
A diode-pumped Nd:YAG acousto-optically(A-O) Q-switched laser at wavelength 946 nm formed with a simple plane-plane cavity has been demonstrated.The maximum average output power was 850 mW.The highest peak power was 5...A diode-pumped Nd:YAG acousto-optically(A-O) Q-switched laser at wavelength 946 nm formed with a simple plane-plane cavity has been demonstrated.The maximum average output power was 850 mW.The highest peak power was 531 W with the pulse repetition rate of 20 kHz and pulse width of 80 ns at the incident pump power of 19.5 W.展开更多
Objective：To implant 80 mm-long artificial esophagi constructed of biomaterial in dogs, observe the perioperative survival rates and the incidence of postoperative complications, and study the mechanisms of postopera...Objective：To implant 80 mm-long artificial esophagi constructed of biomaterial in dogs, observe the perioperative survival rates and the incidence of postoperative complications, and study the mechanisms of postoperative healing. Methods： Specimens of the implanted esophagus, the ＂neo-esophagi＂, were taken for histopathologic study 1, 3, 6, 12, 24 months after operation. Results： The incidence of anastomotic leakage after the artificial esophagus implantation was 3.33%. The perioperative survival rate was 96.67%. The incidence of postoperative stenosis in the ＂neo-esophagi＂ was 81.48%; the stenoses were treated by expanding with esophagoscopy and implanting a stent. Epithelization of the mucosa in the ＂neo-esophagi＂ was completed in 3 to 6 months after surgery Structures such as submucosal muscle layers, mucous glands, nerve fibers, capillaries, etc. were regenerated after 12 months, and then reconstruction of the fibrous connective tissue layer was completed. Conclusion： Implanting a biomaterial artificial esophagus accomplishes safe reconstruction of defects in the esophagus. Advanced cellular structure of ＂neo-esophagus＂ can be regenerated after 1 year. Postoperative stenosis, which is related to hyperplasia and retraction of scar tissue, is still the most common complications which limiting the clinical application of the artificial esophagus.展开更多
Objective: Bronchopleural fistula (BPF) is a life threatening complication after pneumonectomy. Extra thoracic skeletal muscle transposition especially latissimus dorsi muscle flap (LDMF) had been used to prevent this...Objective: Bronchopleural fistula (BPF) is a life threatening complication after pneumonectomy. Extra thoracic skeletal muscle transposition especially latissimus dorsi muscle flap (LDMF) had been used to prevent this complication. The aim of this study was to assess the effectiveness of LDMF in preventing BPF developing after extrapleural pneumonectomy (EPP) and external radiation therapy in malignant pleural mesothelioma (MPM). Methods: Between May 1999 and Dec. 2008, 37 patients with MPM were operated upon by EPP using LDMF prophylactically to reinforce the bronchial stump, and then received external radiation therapy with or without postoperative chemotherapy. Results: The mean age of all patients was 46.7 (range 26-57) years. Twenty five patients were males and 12 patients were females. Twenty three patients had MPM of the right side and 14 patients had MPM of the left side. The peri-operative mortality was 2.7% and only few flap related postoperative morbidity were reported in the form of minor seroma and subcutaneous surgical emphysema. The median follow up was 17 (range 9-43) months. All cases completed their postoperative external radiation therapy with no reported cases of early or late BPF. Conclusion: Intrathoracic pedicled LDMF transposition is proved to be effective in prevention of BPF developing after EPP and external radiation therapy in MPM and it is advised to be a routine step in EPP in these cases and to use more sophisticated technique of postoperative external beam radiotherapy (3D conformal or IMRT) to minimize this complication.展开更多
As the operation time of heat exchanger is increased, the thermal performance of them is gradually degraded due to fouling generated by water-borne deposits which are known to reduce the thermal efficiencies. Currentl...As the operation time of heat exchanger is increased, the thermal performance of them is gradually degraded due to fouling generated by water-borne deposits which are known to reduce the thermal efficiencies. Currently, thermal performance management of heat exchangers is more importantly issued for long term operation. Therefore, the performance evaluation techniques are required to improve the present method for the integrity evaluation of heat exchangers because of the exclusion of fouling calculation and the uncertainty analysis. This paper describes the developed thermal performance evaluation technique applied to the safety-related heat exchangers such as component cooling heat exchangers in a nuclear power plants.展开更多
This paper developed a model for pricing catastrophe bond whose trigger is loss index. In the model Esscher transform which is a facility usually used in actuarial science now provides an easy way to calculate Radon-N...This paper developed a model for pricing catastrophe bond whose trigger is loss index. In the model Esscher transform which is a facility usually used in actuarial science now provides an easy way to calculate Radon-Nikodym derivative so that the whole pricing process becomes easier to understand. At the end of this paper we use this model to price a China typhoon catastrophe bond which is also designed by us.展开更多
文摘Aortic stenosis is the most common native valve disease, affecting up to 5% of the elderly population. Surgical aortic valve replacement reduces symptoms and improves survival, and is the definitive therapy in patients with symptomatic severe aortic stenosis. However, despite the good results of classic surgery, risk is markedly increased in elderly patients with co-morbidities. Transcatheter aortic valve replacement （TAVR） allows implantation of a prosthetic heart valve within the diseased native aortic valve without the need for open heart surgery and cardiopulmonary bypass, offering a new therapeutic option to elderly patients considered at high surgical risk or with contraindications to surgery. To date, several multicenter registries and a randomized trial have confirmed the safety and efficacy of TAVR in those patients. In this chapter, we review the background and clinical applications of TAVR in elderly patients.
文摘A diode-pumped Nd:YAG acousto-optically(A-O) Q-switched laser at wavelength 946 nm formed with a simple plane-plane cavity has been demonstrated.The maximum average output power was 850 mW.The highest peak power was 531 W with the pulse repetition rate of 20 kHz and pulse width of 80 ns at the incident pump power of 19.5 W.
基金Supported by the Science Foundation from Sci-Tech Office of Guangdong Province(A3020103)Science Foundation from Sci-Tech Bureau of Guangzhou City(2004Z3-E0551).
文摘Objective：To implant 80 mm-long artificial esophagi constructed of biomaterial in dogs, observe the perioperative survival rates and the incidence of postoperative complications, and study the mechanisms of postoperative healing. Methods： Specimens of the implanted esophagus, the ＂neo-esophagi＂, were taken for histopathologic study 1, 3, 6, 12, 24 months after operation. Results： The incidence of anastomotic leakage after the artificial esophagus implantation was 3.33%. The perioperative survival rate was 96.67%. The incidence of postoperative stenosis in the ＂neo-esophagi＂ was 81.48%; the stenoses were treated by expanding with esophagoscopy and implanting a stent. Epithelization of the mucosa in the ＂neo-esophagi＂ was completed in 3 to 6 months after surgery Structures such as submucosal muscle layers, mucous glands, nerve fibers, capillaries, etc. were regenerated after 12 months, and then reconstruction of the fibrous connective tissue layer was completed. Conclusion： Implanting a biomaterial artificial esophagus accomplishes safe reconstruction of defects in the esophagus. Advanced cellular structure of ＂neo-esophagus＂ can be regenerated after 1 year. Postoperative stenosis, which is related to hyperplasia and retraction of scar tissue, is still the most common complications which limiting the clinical application of the artificial esophagus.
文摘Objective: Bronchopleural fistula (BPF) is a life threatening complication after pneumonectomy. Extra thoracic skeletal muscle transposition especially latissimus dorsi muscle flap (LDMF) had been used to prevent this complication. The aim of this study was to assess the effectiveness of LDMF in preventing BPF developing after extrapleural pneumonectomy (EPP) and external radiation therapy in malignant pleural mesothelioma (MPM). Methods: Between May 1999 and Dec. 2008, 37 patients with MPM were operated upon by EPP using LDMF prophylactically to reinforce the bronchial stump, and then received external radiation therapy with or without postoperative chemotherapy. Results: The mean age of all patients was 46.7 (range 26-57) years. Twenty five patients were males and 12 patients were females. Twenty three patients had MPM of the right side and 14 patients had MPM of the left side. The peri-operative mortality was 2.7% and only few flap related postoperative morbidity were reported in the form of minor seroma and subcutaneous surgical emphysema. The median follow up was 17 (range 9-43) months. All cases completed their postoperative external radiation therapy with no reported cases of early or late BPF. Conclusion: Intrathoracic pedicled LDMF transposition is proved to be effective in prevention of BPF developing after EPP and external radiation therapy in MPM and it is advised to be a routine step in EPP in these cases and to use more sophisticated technique of postoperative external beam radiotherapy (3D conformal or IMRT) to minimize this complication.
文摘As the operation time of heat exchanger is increased, the thermal performance of them is gradually degraded due to fouling generated by water-borne deposits which are known to reduce the thermal efficiencies. Currently, thermal performance management of heat exchangers is more importantly issued for long term operation. Therefore, the performance evaluation techniques are required to improve the present method for the integrity evaluation of heat exchangers because of the exclusion of fouling calculation and the uncertainty analysis. This paper describes the developed thermal performance evaluation technique applied to the safety-related heat exchangers such as component cooling heat exchangers in a nuclear power plants.
文摘This paper developed a model for pricing catastrophe bond whose trigger is loss index. In the model Esscher transform which is a facility usually used in actuarial science now provides an easy way to calculate Radon-Nikodym derivative so that the whole pricing process becomes easier to understand. At the end of this paper we use this model to price a China typhoon catastrophe bond which is also designed by us.
