Publications (3)5.51 Total impact
Article: Determinants of exercise-induced pulmonary hypertension in patients with normal left ventricular ejection fraction.[show abstract] [hide abstract]
ABSTRACT: Pulmonary hypertension (PH) can occur during exercise and has an adverse effect on functional status, exercise tolerance and prognosis. However, the role of cardiac function abnormalities on exercise-induced PH in patients with normal left ventricular ejection fraction (LVEF) is unclear. To analyse exercise-induced PH determinants in patients with normal LVEF. 396 subjects (160 male, mean age 55 (SD 13)) referred for exercise echocardiography underwent a graded, symptom-limited, supine bicycle exercise with two-dimensional and Doppler echocardiography. Tricuspid regurgitation (TR) velocity was measured at rest and during exercise. Pulmonary artery systolic pressure (PASP) was estimated from TR velocity by adding a right atrial pressure of 10 mm Hg. Patients were classified according to exercise induced PH, defined as present if PASP >50 mm Hg at 50 W of exercise. 135 patients (34%) had PASP >50 mm Hg during exercise. Patients with exercise-induced PH were older, more commonly female and had shorter exercise duration; however, LVEF was significantly higher. The systolic blood pressure at rest and during exercise was significantly higher in patients with exercise-induced PH (rest, 125 (18) vs 132 (18) mm Hg, p = 0.0003; 25 W, 146 (21) vs 157 (21) mm Hg, p<0.0001; 50 W, 157 (24) vs 170 (22) mm Hg, p<0.0001; 75 W, 168 (23) vs 183 (22) mm Hg, p<0.0001). Despite similar resting oxygen saturation, exercise oxygen saturation was significantly lower in subjects with exercise-induced PH than in those without. Numerous echocardiographic variables were significantly different between groups. In multivariate analysis, resting TR velocity (p<0.0001), E/E' (p = 0.027), age and gender were the strongest predictors of PASP during exercise. Exercise-induced PH is common even in subjects with normal LVEF. It is strongly associated with E/E' ratio, TR velocity, age, systolic blood pressure during exercise and gender.Heart (British Cardiac Society) 03/2009; 95(6):490-4. · 4.22 Impact Factor
Article: Electrochemical properties of polypropylene membranes modified by the plasma polymerization coating of SO2/acetylene[show abstract] [hide abstract]
ABSTRACT: Polypropylene membranes were modified by the plasma etching of SO2, SO2O2, or SO2H2O, followed by the plasma polymerization coating of SO2/acetylene. The conditions for SO2 plasma etching were optimized by the measurement of the ion-exchange capacity (IEC) as a function of the plasma-etching power (10–30 W), gas pressure (40–60 mTorr), and treatment time (15–120 s). For the plasma etching of SO2O2 and SO2H2O, only the pressure ratio (SO2/O2 and SO2/H2O) was optimized under the optimized conditions determined from SO2 plasma etching. Plasma etching was then combined with the plasma polymerization coating of SO2/acetylene, for which the conditions were again optimized by the measurement of the IEC as a function of the plasma power (10–40 W), chamber pressure (50–200 mTorr), SO2/acetylene ratio (15/135–60/90), and treatment time (0–10 min). Next, the electrical resistance and water uptake were evaluated. The modified membranes were also analyzed with scanning electron microscopy, whereas plasma polymer coatings were characterized with Fourier transform infrared/attenuated total reflection. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3692–3699, 2006Journal of Applied Polymer Science 01/2006; 99(6):3692 - 3699. · 1.29 Impact Factor
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ABSTRACT: Commercial polypropylene (PP) membranes were modified by plasma polymerization coating of acrylic acid, in combination with oxygen flow or oxygen plasma etching. First, conditions for plasma polymerization coating were optimized in terms of the chemical resistance of the coatings and their ion exchange capacity as a function of plasma power, internal pressure and treatment time. Next, the plasma polymerization coating of acrylic acid was combined with oxygen flow or oxygen plasma etching, and their conditions were also optimized by measuring the ion exchange capacity. Finally, the modified membranes were subjected to electrical resistance and transport number measurements and characterized by α-step, FT-IR/ATR and SEM. Among the modification methods, oxygen plasma etching followed by the plasma polymerization coating of acrylic acid provided the best electrochemical properties with 1.75 meq/g (IEC) and 112 Ω cm2 (ER), 0.88 (TN).Journal of Membrane Science.