近年来,中央银行数字货币(CBDC)受到全球多个国家和地区的高度关注.双离线交易作为CBDC的可选属性,在无网络连接的情况下进行支付,被认为具有较大的实用价值.面向CBDC的双离线匿名支付场景,基于可信执行环境(TEE)和安全单元(SE)技术,提...近年来,中央银行数字货币(CBDC)受到全球多个国家和地区的高度关注.双离线交易作为CBDC的可选属性,在无网络连接的情况下进行支付,被认为具有较大的实用价值.面向CBDC的双离线匿名支付场景,基于可信执行环境(TEE)和安全单元(SE)技术,提出了一种专为移动平台设计的高效双离线匿名支付方案(dual offline anonymous E-payment for mobile devices,OAPM).OAPM适用于资源受限的移动设备,允许移动付款者在不联网状态下安全地向收款者支付数字货币,且不向收款者及商业银行泄露个人隐私信息,付款者的支付行为也不会被链接,同时允许收款者设备处于离线状态,监管机构(如中央银行)在必要情况下能够识别匿名付款者的真实身份.该方案满足数字货币交易的多项重要属性,包括正确性、不可链接性、可追踪性、不可陷害性、机密性、真实性、防双花性以及可控匿名性等.实现了原型系统,并对可能的参数进行了评估.安全性分析和实验结果表明,该方案从安全性和效率两方面均能满足移动用户CBDC双离线交易的实际需求.展开更多
Background: Aortic stenosis (AS) is caused by either age-related degeneration of aortic valve or congenital malformation of aortic cusps. Severe aortic valve stenosis is a clinically emerging diagnosis in the current ...Background: Aortic stenosis (AS) is caused by either age-related degeneration of aortic valve or congenital malformation of aortic cusps. Severe aortic valve stenosis is a clinically emerging diagnosis in the current world. The three cardinal signs of severe AS are dyspnea, syncope, and angina. Transcatheter aortic valve implantation is one of the safe and effective methods for treating severe aortic valve stenosis, and an alternative to surgery in high-risk patients. Aortic valve calcification and changes after TAVI were specifically assessed by computed tomography. Excessive aortic valve calcification is related to procedural complications. A possible consequence is obstruction of coronary ostia. Heavy calcification of the aortic valve and surrounding structure is an important risk factor for coronary obstruction, heart block, and embolization during aortic valve implantation (TAVI). Here we present a case of an elderly old man, where critical ostial left main coronary artery (LMCA) disease was caused by shifting of a calcium speck rather than obstruction with native leaflet. He was successfully rescued by an emergent CABG. Methods and Results: This is a case of a 69-year-old man with severe calcific aortic stenosis and single-vessel CAD who underwent TAVI with a relatively unremarkable course. Notably, his pre-operative TAVI angiography showed no LMCA stenosis. But 10 days later he presented to the ER with acute myocardial infarction with peak high-intensity troponins, diffuse ST changes, and cardiogenic shock. Urgent coronary angiography and intravascular ultrasound showed critical LMCA stenosis caused by a speck of calcium externally abating the vessel. He underwent emergency coronary artery bypass grafting;intraoperative TEE confirmed the etiology. He had an uneventful postoperative course and was successfully weaned off vasoactive medications. Conclusion: This case illustrates that obstruction of coronary ostia could be a possible complication of TAVI. Calcium distribution should factor in TAVI versus surgical candidacy. Calcium shifting should be watched closely during valve deployment, post-TAVI coronary angiogram should be considered if shifting was significant or suspected to compromise coronary arteries.展开更多
目前,超重和肥胖已成为普遍的社会问题,许多研究开始关注总能量消耗（total energy expenditure,TEE）与超重或肥胖发生之间的潜在关系。身体活动能量消耗（physical activity energy expenditure,PAEE）是TEE的最大可变因素。准确测定...目前,超重和肥胖已成为普遍的社会问题,许多研究开始关注总能量消耗（total energy expenditure,TEE）与超重或肥胖发生之间的潜在关系。身体活动能量消耗（physical activity energy expenditure,PAEE）是TEE的最大可变因素。准确测定能量消耗,特别是体力活动的能量消耗,了解某类人群身体活动水平,对有针对性地指导其科学运动和制定膳食推荐标准有重要意义。展开更多
文摘近年来,中央银行数字货币(CBDC)受到全球多个国家和地区的高度关注.双离线交易作为CBDC的可选属性,在无网络连接的情况下进行支付,被认为具有较大的实用价值.面向CBDC的双离线匿名支付场景,基于可信执行环境(TEE)和安全单元(SE)技术,提出了一种专为移动平台设计的高效双离线匿名支付方案(dual offline anonymous E-payment for mobile devices,OAPM).OAPM适用于资源受限的移动设备,允许移动付款者在不联网状态下安全地向收款者支付数字货币,且不向收款者及商业银行泄露个人隐私信息,付款者的支付行为也不会被链接,同时允许收款者设备处于离线状态,监管机构(如中央银行)在必要情况下能够识别匿名付款者的真实身份.该方案满足数字货币交易的多项重要属性,包括正确性、不可链接性、可追踪性、不可陷害性、机密性、真实性、防双花性以及可控匿名性等.实现了原型系统,并对可能的参数进行了评估.安全性分析和实验结果表明,该方案从安全性和效率两方面均能满足移动用户CBDC双离线交易的实际需求.
文摘Background: Aortic stenosis (AS) is caused by either age-related degeneration of aortic valve or congenital malformation of aortic cusps. Severe aortic valve stenosis is a clinically emerging diagnosis in the current world. The three cardinal signs of severe AS are dyspnea, syncope, and angina. Transcatheter aortic valve implantation is one of the safe and effective methods for treating severe aortic valve stenosis, and an alternative to surgery in high-risk patients. Aortic valve calcification and changes after TAVI were specifically assessed by computed tomography. Excessive aortic valve calcification is related to procedural complications. A possible consequence is obstruction of coronary ostia. Heavy calcification of the aortic valve and surrounding structure is an important risk factor for coronary obstruction, heart block, and embolization during aortic valve implantation (TAVI). Here we present a case of an elderly old man, where critical ostial left main coronary artery (LMCA) disease was caused by shifting of a calcium speck rather than obstruction with native leaflet. He was successfully rescued by an emergent CABG. Methods and Results: This is a case of a 69-year-old man with severe calcific aortic stenosis and single-vessel CAD who underwent TAVI with a relatively unremarkable course. Notably, his pre-operative TAVI angiography showed no LMCA stenosis. But 10 days later he presented to the ER with acute myocardial infarction with peak high-intensity troponins, diffuse ST changes, and cardiogenic shock. Urgent coronary angiography and intravascular ultrasound showed critical LMCA stenosis caused by a speck of calcium externally abating the vessel. He underwent emergency coronary artery bypass grafting;intraoperative TEE confirmed the etiology. He had an uneventful postoperative course and was successfully weaned off vasoactive medications. Conclusion: This case illustrates that obstruction of coronary ostia could be a possible complication of TAVI. Calcium distribution should factor in TAVI versus surgical candidacy. Calcium shifting should be watched closely during valve deployment, post-TAVI coronary angiogram should be considered if shifting was significant or suspected to compromise coronary arteries.
文摘目前,超重和肥胖已成为普遍的社会问题,许多研究开始关注总能量消耗（total energy expenditure,TEE）与超重或肥胖发生之间的潜在关系。身体活动能量消耗（physical activity energy expenditure,PAEE）是TEE的最大可变因素。准确测定能量消耗,特别是体力活动的能量消耗,了解某类人群身体活动水平,对有针对性地指导其科学运动和制定膳食推荐标准有重要意义。
