Browsing by Author "Wu, Yi-Fan"

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A reconfigurable quadri-polarization diversity aperture-coupled patch antenna
(2007-03-01)
Wu, Yi-Fan
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Wu, Chun-Hsien
;
Lai, Don-Yen
;
Chen, Fu-Chiarng
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電信工程研究所
We present a novel reconfigurable quadri-polarization diversity aperture-coupled patch antenna which can provide four polarization states. By controlling the do bias voltage of the pin-diodes on the feeding network, we can reconfigure the proposed antenna to provide a pair of orthogonal linear polarizations and a pair of orthogonal circular polarizations. Numerical and experimental results validate our design. This novel antenna provides potential polarization diversity features for wireless local area networks and multiple-input multiple-output systems.
Long-term Prognostic Value of Estimated Plasma Volume in Heart Failure with Preserved Ejection Fraction
(2019-10-07)
Huang, Chen-Yu
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Lin, Ting-Tse
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Wu, Yi-Fan
;
Chiang, Fu-Tien
;
Wu, Cho-Kai
Plasma volume, estimated by several indirect methods, has been viewed as a biological surrogate for intravascular fluid status. The clinical implication of estimated plasma volume status (ePVS) for long term outcomes in heart failure with preserved ejection fraction (HFpEF) remains unclear. We investigate the prognostic value of ePVS calculated by Strauss formula and its association with cardiovascular events and mortality in a prospective HFpEF cohort. There were 449 individuals met the inclusion criteria of our cohort. Estimated plasma volume variation (Delta ePVS) and its instantaneous derivatives were calculated by the Strauss formula. Our study endpoints were events of heart failure hospitalization and mortality. Kaplan-Meier estimates and Cox regression analysis were applied to determine the power of Delta ePVS and baseline ePVS in predicting long term cardiovascular outcomes. Both baseline ePVS and Delta ePVS were independent predictors of heart failure hospitalization and mortality. Kaplan-Meier estimates of these outcomes stratified by optimal cut-off value showed that HFpEF individuals with higher baseline ePVS and Delta ePVS were associated with elevated risk of composite endpoint of heart failure hospitalization and mortality. This study demonstrated the prognostic value of a novel biological surrogate, instantaneous derivatives ePVS, in predicting long term cardiovascular outcomes in HFpEF population. Monitoring instantaneous plasma volume may assist in identifying patients at high risk for future cardiovascular events. Further prospective studies validating the role of ePVS in predicting long-term prognosis in patients with HFpEF are warranted.
Myocardial adipose deposition and the development of heart failure with preserved ejection fraction
(1970-01-01)
Wu, Cho-Kai
;
Lee, Jen-Kuang
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Hsu, Jung-Chi
;
Su, Mao-Yuan M.
;
Wu, Yi-Fan
Aims It has been proposed that an increase of myocardial adiposity is related to left ventricular (LV) diastolic dysfunction. The specific roles of myocardial steatosis including epicardial fat and intramyocardial fat for diastolic function are unknown in those patients suffering heart failure (HF) with reduced (HFrEF) or preserved ejection fraction (HFpEF). This study aims to determine the complex relationship between myocardial adiposity in patients with HFrEF or HFpEF. Methods and results Using cardiac magnetic resonance imaging (CMRI), myocardial steatosis was measured in 305 subjects (34 patients with HFrEF, 163 with HFpEF, and 108 non-HF controls). We also evaluated cardiac structure and diastolic and systolic function by echocardiography and CMRI. Patients with HFpEF had significantly more intramyocardial fat than HFrEF patients or non-HF controls [intramyocardial fat content (%), 1.56 (1.26, 1.89) vs. 0.75 (0.50, 0.87) and 1.0 (0.79, 1.15), P < 0.05]. Intramyocardial fat amount (%) was higher in HFpEF women than in men [1.91% (1.17%, 2.32%) vs. 1.22 (0.87%, 2.02%), P = 0.01]. When estimated by CMRI (left ventricular peak filling rate), echocardiographic E/e ' level, or left atrial volume index, intramyocardial fat correlated with LV diastolic dysfunction parameters in HFpEF patients, and this was independent of age, co-morbidities, body mass index, gender, and myocardial fibrosis (standardized coefficient: beta = -0.34, P = 0.03; beta = 0.29, P = 0.025; and beta = 0.25, P = 0.02, respectively). Conclusions Patients with HFpEF had significantly more intramyocardial fat than HFrEF patients or non-HF controls. Independent of risk factors or gender, intramyocardial fat correlated with LV diastolic dysfunction parameters in HFpEF patients.
Treatment Success with Titratable Thermoplastic Mandibular Advancement Devices for Obstructive Sleep Apnea: A Comparison of Patient Characteristics
(2017-03-01)
Wang, Tang-Chuan
;
Tsou, Yung-An
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Wu, Yi-Fan
;
Huang, Chia-Chang
;
Lin, Wesley Wen-Yang
A titratable thermoplastic mandibular advancement devices (MAD) is clearly an effective treatment option in some patients with obstructive sleep apnea (OSA). Determining which patients may be more likely to respond to treatment with thermoplastic MADs and to adhere to treatment would be of obvious clinical relevance. This was an experimental descriptive study (N = 60). Patients with OSA were instructed to wear a titratable thermoplastic MAD for 3 months. Treatment success was defined as a 50% reduction from baseline in the apnea-hypopnea index (AHI) or AHI <10 when wearing MAD. Adherence was defined as MAD use 5 nights/week. Treatment was successful in 66.7% of patients and 60.0% were adherent. All Polysomnographic parameters and visual analogue scale scores (sleep quality, snoring, waking refreshed) were significantly improved after treatment. The patients in whom treatment failed had significantly higher neck circumferences (39.3 cm vs. 37.5 cm, p = 0.014), higher baseline AHI values (26.6 vs. 18.0, p = 0.016), and smaller AHI reduction (-31.8 vs -53.1, p < 0.001) than those in the group in whom treatment succeeded. There were no significant differences in Polysomnographic, cephalometric, or visual analogue scale measures between patients for whom treatment was and was not successful, regardless of baseline values or the change rates after the MAD was placed. Titratable thermoplastic MADs can improve indicators of sleep quality, even in patients in whom treatment is considered to have failed.