Perfluorodioxolane Polymers for Gas Separation Membrane Applications.

Since the discovery of polytetrafluoroethylene (PTFE) in 1938, fluorinated polymers have drawn attention in the chemical and pharmaceutical field, as well as in optical and microelectronics applications. The reasons for this attention are their high thermal and oxidative stability, excellent chemical resistance, superior electrical insulating ability, and optical transmission properties. Despite their unprecedented combination of desirable attributes, PTFE and copolymers of tetrafluoroethylene (TFE) with hexafluoropropylene and perfluoropropylvinylether are crystalline and exhibit poor solubility in solvents, which makes their processability very challenging. Since the 1980s, several classes of solvent-soluble amorphous perfluorinated polymers showing even better optical and gas transport properties were developed and commercialized. Amorphous perfluoropolymers exhibit, however, moderate selectivity in gas and liquid separations. Recently, we have synthesized various new perfluorodioxolane polymers which are amorphous, soluble, chemically and thermally stable, while exhibiting much enhanced selectivity. In this article, we review state-of-the-art and recent progress in these perfluorodioxolane polymers for gas separation membrane applications.

Home Exercise Training Improves Exercise Capacity in Cirrhosis Patients: Role of Exercise Adherence.

Cirrhosis patients have reduced peak aerobic power (peak VO2) that is associated with reduced survival. Supervised exercise training increases exercise tolerance. The effect of home-based exercise training (HET) in cirrhosis is unknown. The objective was to evaluate the safety and efficacy of 8 weeks of HET on peak VO2, 6-minute walk distance (6MWD), muscle mass, and quality of life in cirrhosis. Random assignment to 8 weeks of HET (moderate to high intensity cycling exercise, 3 days/week) or usual care. Exercise adherence defined as completing ≥80% training sessions. Paired t-tests and analysis of covariance used for comparisons. Forty patients enrolled: 58% male, mean age 57 y, 70% Child Pugh-A. Between group increases in peak VO2 (1.7, 95% CI: -0.33 to 3.7 ml/kg/min, p = 0.09) and 6MWD (33.7, 95% CI: 5.1 to 62.4 m, p = 0.02) were greater after HET versus usual care. Improvements even more marked in adherent subjects for peak VO2 (2.8, 95% CI: 0.5-5.2 mL/kg/min, p = 0.02) and 6MWD (46.4, 95% CI: 12.4-80.5 m, p = 0.009). No adverse events occurred during testing or HET. Eight weeks of HET is a safe and effective intervention to improve exercise capacity in cirrhosis, with maximal benefits occurring in those who complete ≥80% of the program.

Volume and Patterns of Physical Activity Across the Health and Heart Failure Continuum.

BACKGROUND: The benefits of regular physical activity (PA) are well documented in patients with heart failure (HF), however the amount and intensity of objectively measured PA and sedentary behaviour in HF with preserved (HFPEF) or reduced ejection fraction (HFREF) is not well known. METHODS: In a cross-sectional observational study the energy expenditure of 151 participants (HFPEF: n = 53; HFREF: n = 16; at-risk for HF: n = 48; control participants: n = 34) using SenseWear Mini Armbands (Body Media, Inc, Pittsburgh, PA) were monitored. PA outcomes included time spent in different PA intensities (light and moderate-vigorous PA), sedentary time, steps per day, total daily energy expenditure, PA energy expenditure, and the patterns of PA in bouts of ≥ 10 minutes of moderate-vigorous PA. RESULTS: The patients with HFPEF had the lowest volume of activity across the 4 groups. After adjusting for covariates, only steps per day remained significantly different across groups (P = 0.0005). A comparison of HFPEF vs HFREF indicated a higher amount of time in bouts of ≥ 10 minutes of moderate-vigorous PA for patients with HFREF (median, 2.4 [interquartile range, 0-13.5] vs 26 [3.7-46.8]; P = 0.0075). In the at-risk group, PA was lower than the recommended levels in the guidelines. CONCLUSIONS: Our findings suggest step count as the most robust outcome in evaluating daily PA in this population. Also, patients with HFPEF showed to be the least active group in the HF continuum. Monitoring volume and pattern of PA for those at risk of HF and patients with HFPEF could help to identify sedentary individuals and to develop tailored behavioural interventions for them.

Eight weeks of exercise training increases aerobic capacity and muscle mass and reduces fatigue in patients with cirrhosis.

BACKGROUND & AIMS: Patients with cirrhosis have reduced exercise tolerance, measured objectively as decreased peak exercise oxygen uptake (peak VO2). Reduced peak VO2 is associated with decreased survival time. The effect of aerobic exercise training on peak VO2 has not been well studied in patients with cirrhosis. We evaluated the safety and efficacy of 8 weeks of supervised exercise on peak VO2, quadriceps muscle thickness, and quality of life. METHODS: In a prospective pilot study, stable patients (79% male, 57.6 ± 6.7 years old) with Child-Pugh class A or B cirrhosis (mean Model for End-Stage Liver Disease score, 10 ± 2.2) were randomly assigned to groups that received exercise training (n = 9) or usual care (controls, n = 10) at the University of Alberta Hospital in Canada from February through June 2013. Supervised exercise was performed on a cycle ergometer 3 days/week for 8 weeks at 60%-80% of baseline peak VO2. Peak VO2, quadriceps muscle thickness (measured by ultrasound), thigh circumference, answers from Chronic Liver Disease Questionnaires, EQ-visual analogue scales, 6-minute walk distance, and Model for End-Stage Liver Disease scores were evaluated at baseline and at week 8. Analysis of covariance was used to compare variables. RESULTS: At week 8, peak VO2 was 5.3 mL/kg/min higher in the exercise group compared with controls (95% confidence interval, 2.9-7.8; P = .001). Thigh circumference (P = .001), thigh muscle thickness (P = .01), and EQ-visual analogue scale determined self-perceived health status (P = .01) was also significantly higher in the exercise group compared with controls at week 8; fatigue subscores of the Chronic Liver Disease Questionnaires were lower in the exercise group compared with controls (P = .01). No adverse events occurred during cardiopulmonary exercise testing or training. CONCLUSIONS: In a controlled prospective pilot trial, 8 weeks of supervised aerobic exercise training increased peak VO2 and muscle mass and reduced fatigue in patients with cirrhosis. No relevant adverse effects were observed. Larger trials are needed to evaluate the effects of exercise in patients with cirrhosis. ClinicalTrials.gov number: NCT01799785.