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Transient stress cardiomyopathies in the elderly： Clinical ＆ Pathophysiologic considerations

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Journal of Geriatric Cardiology 2012年第1期9卷 38-48页

作者： michael a chen Harborview Medical Center/University of Washington 325 9th Avenue Box 359748 Seattle WA 98104 USA

短暂导致压力的心肌症逐渐地被认出了并且当时稀罕，他们趋于多于另外的人口统计的组影响老女人。一种类型，经常叫的 tako-tsubo 心肌症(TTC ) ，被重要感情或物理的应力典型地触发并且与胸疼痛，心电图(ECG ) 变化和反常的心脏的酶被... 详细信息

短暂导致压力的心肌症逐渐地被认出了并且当时稀罕，他们趋于多于另外的人口统计的组影响老女人。一种类型，经常叫的 tako-tsubo 心肌症(TTC ) ，被重要感情或物理的应力典型地触发并且与胸疼痛，心电图(ECG ) 变化和反常的心脏的酶被联系。重要的左室的地区性的墙运动畸形通常包括运动不能的 “； ballooning”；有正常或底的 hyperdynamic 功能的顶。第二种类型，经常叫的神经原的震惊的心肌层，典型地与 subarachnoid 出血联系了，通常也与 ECG 介绍变化和积极的酶，而是典型的墙打手势看见的畸形包括正常有 akinesis 的基础、顶端的左室的收缩以一种环绕的方式中间洞。pathophysiology，临床的照顾和典型功课，被考察。

关键词：中老年人瞬态应力临床护理心肌病应激性运动异常病理生理蛛网膜下腔

Frailty and cardiovascular disease： potential role of gait speed in surgical risk stratification in older adults

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Journal of Geriatric Cardiology 2015年第1期12卷 44-56页

作者： michael A. chen Harborview Medical Center University of Washington School of Medicine 325 9th Avenue Box 359748 Seattle WA 98104 USA

脆弱近来是一个状态生活衰落和危险，由物理软弱代表了并且减少生理的保守。心血管的疾病的有那些的脆弱份额特征的传染病学和 pathophysiology。步法速度能被用作脆弱的一项措施并且是死亡的一个强大的预言者。推进年龄是为心血管的疾... 详细信息

脆弱近来是一个状态生活衰落和危险，由物理软弱代表了并且减少生理的保守。心血管的疾病的有那些的脆弱份额特征的传染病学和 pathophysiology。步法速度能被用作脆弱的一项措施并且是死亡的一个强大的预言者。推进年龄是为心血管的疾病的一个有势力风险因素并且与不利结果的增加的风险被联系了。更老的成年人近似包括心脏的外科病人的一半，并且占跟随外科的将近 80% 主要复杂并发症和死亡。如果，在更老的病人的病态为心脏的外科正在被考虑预言死亡和专业的传统的风险模型的能力可以改善脆弱由步法速度测量了在他们的评价被包括。在未来脆弱，评价可以在在治疗之中选择帮助，是可能的(例如，为有大动脉的狭窄的病人的外科对经皮的大动脉的阀门代替) 。

关键词：心血管疾病风险模型速度测量老年人手术潜在作用步态生理功能

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基于离散积分滑模的四旋翼编队跟踪控制

控制工程 2024年第1期31卷 134-141页

作者：陈培毓王介鹏张良银杜宝珠陈志强南京理工大学自动化学院江苏南京210094

针对四旋翼编队的轨迹跟踪问题,提出一种基于离散积分滑模的分布式编队控制器。首先,建立四旋翼的离散模型,并将其分为位置系统和姿态系统。其次,基于一致性理论和图论知识建立四旋翼编队的拓扑图,对位置系统采用离散积分滑模控制方法,... 详细信息

针对四旋翼编队的轨迹跟踪问题,提出一种基于离散积分滑模的分布式编队控制器。首先,建立四旋翼的离散模型,并将其分为位置系统和姿态系统。其次,基于一致性理论和图论知识建立四旋翼编队的拓扑图,对位置系统采用离散积分滑模控制方法,对姿态系统采用指数趋近律的滑模控制方法,并进行编队一致性分析。最后,利用离散扩张观测器估计并补偿外界干扰和不可建模部分。仿真结果表明,所设计的分布式控制器能使四旋翼形成编队并跟踪给定轨迹。

关键词：四旋翼编队离散时间积分滑模扩张观测器

Effect of age on aortic atherosclerosis

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Journal of Geriatric Cardiology 2013年第2期10卷 135-140页

作者： michael A. chen Miwa Kawakubo Patrick M. Colletti Dongxiang Xu Laurie LaBree Dustin Robert Detrano Stanley P Azen Nathan D. Wong Xue-Qiao Zhao Department of Medicine Division of Cardiology Harborview Medical Center/University of Washington 325 9th Avenue Box 359748 Seattle WA 98104 USA Department of Preventive Medicine Division of Biostatistics Keck School of Medicine of the University of Southern California 2001 N Soto Street SSB 201A M/C 9234 Los Angeles CA 90089-9237 USA Department of Radiology Keck School of Medicine of the University of Southern California1 1500 San Pablo Street Second Floor Imaging Los Angeles CA 90033 USA Department of Radiology University of Washington School of Medicine Box 357115 1959 Pacific Street RR-215 Seattle WA 98195-7117 USA Department of Radiological Sciences University of California Irvine School of Medicine 101 the City Drive South Route 140 Orange CA 92868 USA Department of Medicine UC Irvine School of Medicine 333 City Blvd. West Suite 400 Orange CA 92868-3298 USA

Objective To examine the association of atherosclerosis burden in the survivors of an asymptomatic elderly cohort study and its relationship to other coronary risk factors (specifically, age) by evaluating aortic atherosclerotic wall burden by magnetic resonance imaging (MRI). Methods A total of 312 participants in an ongoing observational cohort study underwent cardiac and descending thoracic aorta imaging by MRI. Maximum wall thickness was measured and the mean wall thickness calculated.Wall/outer wall ratio was used as a normalized wall index (NWI) adjusted for artery size difference among participants. Percent wall volume (PWV) was calculated as NWI ×100.Results In this asymptomatic cohort (mean age: 76 years), the mean (SD) aortic wall area andwall thicknesswere 222 ±45 mm2 and 2.7 ±0.4 mm, respectively. Maximum wall thickness was 3.4 ±0.6 mm, and PWV was 32% ±4%. Women appeared to have smaller wall area,but after correcting for their smaller artery size, had significantly higher PWV than men (P = 0.03). Older age was associatedwith larger wall area (P = 0.04 for trend) with similar PWVs. However, there were no statistically significant associations between standard risk factors,Framingham global risk, or metabolic syndrome status, therapy for cholesterol or hypertension, coronary or aortic calcium score, and the aortic wall burden. Aortic calcificationwas associated with coronary calcification. Conclusions Asymptomatic elderly in this cohort had a greater descending thoracic aortic wall volume that correlated with age, andwomen had a significantly increased PWV compared to men. In these survivors, the atherosclerotic aortic wall burden was not significantly associated with traditional risk factors or with coronary or aortic calcium scores or coronary calcium progression. Results suggest that age, or as yet unidentified risk factor(s), may be responsible for the increase in atherosclerosis.

关键词： Aging Aortic atherosclerosis Atherosclerotic risk factors Magnetic resonance imaging

Atherosclerosis,its risk factors,and cognitive impairment in older adults

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Journal of Geriatric Cardiology 2020年第7期17卷 434-440页

作者： Yun-Li XING michael a chen Ying SUN Moni B Neradilek Xi-Ting WU Dai ZHANG Wei HUANG Yining CUI Qi-Qi YANG Hong-Wei LI Xue-Qiao ZHAO Department of Geriatrics and Gerontology Beijing Friendship HospitalCapital Medical UniversityBeijingChina Division of Cardiology University of WashingtonSeattleWAUSA The Mountain-Whisper-Light Statistics SeattleWAUSA Cardiovascular Center Beijing Friendship HospitalCapital Medical UniversityBeijingChina

Objective To examine the association of atherosclerotic cardiovascular disease(ASCVD)and its risk factors with cognitive impairment in older adults.Methods Six hundred and fourteen subjects,aged≥65 years,from one center(2016–2018)underwent clinical,laboratory assessments and the Montreal Cognitive Assessment(Mo CA).Using regression analysis,the relationship between ASCVD and its risk factors was evaluated in subjects with and without cognitive impairment(MoCA score<26).Results Older age(b=-1.3 per 5 years,95%CI:-1.7 to-0.9,P<0.001),history of stroke(b=-1.6,95%CI:-3.0 to-0.3,P=0.01),and myocardial infarction(MI;b=-2.2,95%CI:-3.6 to-0.8,P=0.003)were independently associated with lower MoCA scores,whereas more education(b=1.5 per 3 years,95%CI:1.1 to 1.9,P<0.001),higher body mass index(BMI;b=0.5 per 3 kg/m^2,95%CI:0.0 to 1.0,P=0.04),higher estimated glomerular filtration rate(eGFR;b=0.8 per 15 U,95%CI:0.1 to 1.4,P=0.03),left ventricular ejection fraction(LVEF;b=0.4 per 5%,95%CI:0 to 0.8,P=0.04)and statin use(b=1.3,95%CI:0.3 to 2.3,P=0.01)were associated with a higher MoCA score.Cognitive impairment was independently associated with older age(OR=1.51 per 5 yrs,95%CI:1.28 to 1.79,P<0.001),less education(OR=0.55 per 3 years,95%CI:0.45 to 0.68,P<0.001),lower BMI(OR=0.78 per 3 kg/m^2,95%CI:0.62 to 0.98,P=0.03)and higher levels of high sensitivity c-reactive protein(hsCRP;OR=1.08 per 1 mg/L,95%CI:1.02 to 1.15,P=0.01).Conclusions Beyond age,cognitive impairment was associated with prior MI/stroke,higher hsCRP,statin use,less education,lower eGFR,BMI and LVEF.

关键词： Atherosclerosis Cognitive impairment Correlation Older adults Risk factors

Near-zero stiffness accelerometer with buckling of tunable electrothermal microbeams

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Microsystems & Nanoengineering 2024年第2期10卷 67-81页

作者： Hussein Hussein chen Wang Rui Amendoeira Esteves michael Kraft Hossein Fariborzi Department of Mechanical Engineering MSFEAAmerican University of BeirutBeirut11072020Lebanon King Abdullah University of Science and Technology Thuwal23955-6900Saudi Arabia ESAT-MNS University of Leuven3001LeuvenBelgium

Pre-shaped microbeams,curved or inclined,are widely used in MEMS for their interesting stiffness properties.These mechanisms allow a wide range of positive and negative stiffness tuning in their direction of motion.A mechanism of pre-shaped beams with opposite curvature,connected in a parallel configuration,can be electrothermally tuned to reach a near-zero or negative stiffness behavior at the as-fabricated position.The simple structure helps incorporate the tunable spring mechanism in different designs for accelerometers,even with different transduction technologies.The sensitivity of the accelerometer can be considerably increased or tuned for different applications by electrothermally changing the stiffness of the spring mechanism.Opposite inclined beams are implemented in a capacitive micromachined accelerometer.The measurements on fabricated prototypes showed more than 55 times gain in sensitivity compared to their initial sensitivity.The experiments showed promising results in enhancing the resolution of acceleration sensing and the potential to reach unprecedent performance in micromachined accelerometers.

关键词： properties. mechanism. stiffness

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质谱技术在北美临床检验中的应用

中华检验医学杂志 2023年第8期46卷 768-774页

作者： michael X.chen 病理学和检验医学系不列颠哥伦比亚大学温哥华加拿大

早期滥用药物的检测推动了质谱技术在北美临床实验室的应用。质谱分析因为其分析灵敏度、特异性和同时检测的能力优势,已经越来越广泛的应用于临床。目前,质谱技术已经成功用于临床小分子化合物、多肽、蛋白质、临床毒理和微生物等常规... 详细信息

早期滥用药物的检测推动了质谱技术在北美临床实验室的应用。质谱分析因为其分析灵敏度、特异性和同时检测的能力优势,已经越来越广泛的应用于临床。目前,质谱技术已经成功用于临床小分子化合物、多肽、蛋白质、临床毒理和微生物等常规检测。尽管还需要更多经过FDA批准的商品化平台和试剂,但毫无疑问质谱技术已经展现出丰富的临床应用。

关键词：质谱分析法临床实验室技术北美洲

Spark plasma sintering of tungsten-based WTaVCr refractory high entropy alloys for nuclear fusion applications

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 146-154页

作者： Yongchul Yoo Xiang Zhang Fei Wang Xin chen Xing-Zhong Li michael Nastasi Bai Cui Department of Mechanical&Materials Engineering University of Nebraska-LincolnLincolnNE 68588USA Nebraska Center for Materials and Nanoscience University of Nebraska-LincolnLincolnNE 68588USA Department of Nuclear Engineering Texas A&M UniversityCollege StationTX 77843USA

W-based WTaVCr refractory high entropy alloys (RHEA) may be novel and promising candidate materials for plasma facing components in the first wall and diverter in fusion reactors. This alloy has been developed by a powder metallurgy process combining mechanical alloying and spark plasma sintering (SPS). The SPSed samples contained two phases, in which the matrix is RHEA with a body-centered cubic structure, while the oxide phase was most likely Ta2VO6through a combined analysis of X-ray diffraction (XRD),energy-dispersive spectroscopy (EDS), and selected area electron diffraction (SAED). The higher oxygen affinity of Ta and V may explain the preferential formation of their oxide phases based on thermodynamic calculations. Electron backscatter diffraction (EBSD) revealed an average grain size of 6.2μm. WTaVCr RHEA showed a peak compressive strength of 2997 MPa at room temperature and much higher micro-and nano-hardness than W and other W-based RHEAs in the literature. Their high Rockwell hardness can be retained to at least 1000°C.

关键词： refractory high entropy alloy plasma-facing material fusion reactor spark plasma sintering

Etching Mechanism of Ti_(3)C_(2)Cl_(2) MXene Phases by CuCl_(2)-Lewis Molten Salt Method

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 863-868页

作者：严明 ZHU Yu HUANG Jiangtao chen Haoyu DENG Yuxiao chen Yanlin 王娟 Jan-michael Albina Hubei Provincial Key Laboratory of Green Materials for Light Industry Hubei University of TechnologyWuhan 430068China New Materials and Green Manufacturing Talent Introduction and Innovation Demonstration Base Hubei University of TechnologyWuhan 430068China Hubei Longzhong Laboratory Xiangyang 441000China

We described a method for obtaining fluorine-free Ti_(3)C_(2)Cl_(2)MXene phases by melting copper in CuCl_(2)instead of aluminum in Ti_(3)AlC_(2).XRD results show that when molten salt CuCl_(2)etches Ti_(3)AlC_(2),it forms an intermediate product Ti_(3)CuC_(2),and then reacts with Ti_(3)CuC_(2)to obtain Ti_(3)C_(2)Cl_(2).The reaction of Ti_(3)AlC_(2)and CuCl_(2)at a temperature of 800℃for 2 h to obtain Ti_(3)C_(2)Cl_(2)with an optimal lamellar structure is shown in SEM results.The pseudopotential plane-wave(PP-PW)method is used to calculate on the electronic structure.The etching mechanism is investigated by the total energies of each substance.The chemical reaction of Ti_(3)AlC_(2)and CuCl_(2)will first become Ti_(3)CuC_(2)and Cu,and then become Ti_(3)C_(2)Cl_(2)during the Lewis acid etching process,which are consistent with the experimental results.

关键词： molten salt method CuCl_(2) MXene first-principles calculations etching mechanism