Introduction: The most commonly used predictor of aneurysm behavior in clinical decision-making is size. There are however small aneurysms that rupture and certain large aneurysms remain asymptomatic. There is growing...Introduction: The most commonly used predictor of aneurysm behavior in clinical decision-making is size. There are however small aneurysms that rupture and certain large aneurysms remain asymptomatic. There is growing evidence to suggest that other variables may provide better information on metabolic and physiological properties of aortic wall and therefore better predict aneurysm behavior. Methods: The literature was systematically reviewed from 1975-May 2011 to examine the evidence to support the use of non-invasive imaging modalities that might predict aneurysm behavior. Results: Ultrasound can be used to measure multiple dynamic aortic properties (i.e. distensibility and compliance) in addition to diameter. These parameters better predict aneurysm behavior. Computer tomography can utilize assessment of aortic calcification, presence of intra-luminal thrombus and distensibility. Finite element analysis model has been validated in-vivo to calculate peak wall stress, assess effects of intra-luminal thrombus and calcification. It however relies on assumptions related to aneurysm properties and therefore remains relatively inaccurate in the clinical setting. Small numbers of observational human studies have evaluated the role of 18F-FDG PET/CT in aneurysms. Larger studies are needed, as 18F-FDG uptake is patchy and heterogeneous even in small number of patients. It varies in the same patient with time, as aneurysms grow in intermittently. We discuss functional magnetic resonance imaging with novel tracers such as 99 mTc-annexin-V and nanoparticles. Conclusion: Multimodality imaging with complementary methods such as CT, functional MRI (fMRI), ultrasound and physiological measurements improve the definition of aneurysm pathobiology. Larger-scale clinical validation is beginning to promise a new paradigm in cardiovascular diagnostics.展开更多
In this paper,the overall structure design of the Ethernet-based and distributed simulation system for propelling(AAA) fire control is proposed with introducing the concept of system self-configuring pattern.The advan...In this paper,the overall structure design of the Ethernet-based and distributed simulation system for propelling(AAA) fire control is proposed with introducing the concept of system self-configuring pattern.The advantage of this system self-configuring pattern is easy and flexible to configure the modules of the simulation system without doing much more reprogramming work,when the simulation system is needed to add or reduced the modules and simulation computers,and the scale of simulation system is needed to changed.Also the system is structured with standardized and modularized design procedures on the Windows OS platform.展开更多
目的:分析、比较笔形束卷积算法(PBC)和各向异性解析算法(AAA)在非小细胞肺癌(NSCLC)调强放疗计划设计中的剂量学差异。方法:随机选择7例NSCLC患者,采用Eclipse version 7.3.10计划系统提供的PBC算法和AAA算法对每例NSCLC进行IMRT的计...目的:分析、比较笔形束卷积算法(PBC)和各向异性解析算法(AAA)在非小细胞肺癌(NSCLC)调强放疗计划设计中的剂量学差异。方法:随机选择7例NSCLC患者,采用Eclipse version 7.3.10计划系统提供的PBC算法和AAA算法对每例NSCLC进行IMRT的计划设计,比较靶区及危及器官的剂量分布、DVH等指标。结果:两种算法获得治疗计划的靶区剂量均匀性和适形度均无明显差别,食管、心脏、脊髓等危及器官的受量也基本相同。结论:对于NSCLC,剂量计算应采用受呼吸时相影响更小的AAA算法。展开更多
基于AAA(Authentication,Authorization and Accounting)的移动IP协议被用于解决移动IP的认证、授权及计费问题,但在切换时存在较大的时延。本文在分析现有的基于AAA的移动IP基本模型的基础上,提出了一种改进方案。该改进方案通过减少...基于AAA(Authentication,Authorization and Accounting)的移动IP协议被用于解决移动IP的认证、授权及计费问题,但在切换时存在较大的时延。本文在分析现有的基于AAA的移动IP基本模型的基础上,提出了一种改进方案。该改进方案通过减少外地网络与家乡网络之间交换的认证注册消息数量,明显提高了切换的效率。同时通过采用公钥和对称密钥相结合的加密及认证方法,使得该方案具有安全、快速、成本低和扩展性好等优点,较好地满足了移动IP的要求。展开更多
文摘Introduction: The most commonly used predictor of aneurysm behavior in clinical decision-making is size. There are however small aneurysms that rupture and certain large aneurysms remain asymptomatic. There is growing evidence to suggest that other variables may provide better information on metabolic and physiological properties of aortic wall and therefore better predict aneurysm behavior. Methods: The literature was systematically reviewed from 1975-May 2011 to examine the evidence to support the use of non-invasive imaging modalities that might predict aneurysm behavior. Results: Ultrasound can be used to measure multiple dynamic aortic properties (i.e. distensibility and compliance) in addition to diameter. These parameters better predict aneurysm behavior. Computer tomography can utilize assessment of aortic calcification, presence of intra-luminal thrombus and distensibility. Finite element analysis model has been validated in-vivo to calculate peak wall stress, assess effects of intra-luminal thrombus and calcification. It however relies on assumptions related to aneurysm properties and therefore remains relatively inaccurate in the clinical setting. Small numbers of observational human studies have evaluated the role of 18F-FDG PET/CT in aneurysms. Larger studies are needed, as 18F-FDG uptake is patchy and heterogeneous even in small number of patients. It varies in the same patient with time, as aneurysms grow in intermittently. We discuss functional magnetic resonance imaging with novel tracers such as 99 mTc-annexin-V and nanoparticles. Conclusion: Multimodality imaging with complementary methods such as CT, functional MRI (fMRI), ultrasound and physiological measurements improve the definition of aneurysm pathobiology. Larger-scale clinical validation is beginning to promise a new paradigm in cardiovascular diagnostics.
文摘In this paper,the overall structure design of the Ethernet-based and distributed simulation system for propelling(AAA) fire control is proposed with introducing the concept of system self-configuring pattern.The advantage of this system self-configuring pattern is easy and flexible to configure the modules of the simulation system without doing much more reprogramming work,when the simulation system is needed to add or reduced the modules and simulation computers,and the scale of simulation system is needed to changed.Also the system is structured with standardized and modularized design procedures on the Windows OS platform.
文摘目的:分析、比较笔形束卷积算法(PBC)和各向异性解析算法(AAA)在非小细胞肺癌(NSCLC)调强放疗计划设计中的剂量学差异。方法:随机选择7例NSCLC患者,采用Eclipse version 7.3.10计划系统提供的PBC算法和AAA算法对每例NSCLC进行IMRT的计划设计,比较靶区及危及器官的剂量分布、DVH等指标。结果:两种算法获得治疗计划的靶区剂量均匀性和适形度均无明显差别,食管、心脏、脊髓等危及器官的受量也基本相同。结论:对于NSCLC,剂量计算应采用受呼吸时相影响更小的AAA算法。
文摘基于AAA(Authentication,Authorization and Accounting)的移动IP协议被用于解决移动IP的认证、授权及计费问题,但在切换时存在较大的时延。本文在分析现有的基于AAA的移动IP基本模型的基础上,提出了一种改进方案。该改进方案通过减少外地网络与家乡网络之间交换的认证注册消息数量,明显提高了切换的效率。同时通过采用公钥和对称密钥相结合的加密及认证方法,使得该方案具有安全、快速、成本低和扩展性好等优点,较好地满足了移动IP的要求。