Improved Melt Processabilities of Thermosetting Polyimide Matrix Resins for High Temperature Carbon Fiber Composite Applications.

With the goal of improving processability of imide oligomers and achieving of high temperature carbon fiber composite, a series of Thermosetting Matrix Resin solutions (TMR) were prepared by polycondensation of aromatic diamine (3,4'-oxybisbenzenamine, 3,4-ODA) and diester of biphenylene diacid (BPDE) using monoester of 4-phenylethynylphthalic acid (PEPE) as end-capping agent in ethyl alcohol as solvent to afford phenylethynyl-endcapped poly(amic ester) resins with calculated molecular weight (Calc'd Mw) of 1500-10,000. Meanwhile, a series of reactive diluent solutions (RDm) with Calc'd Mw of 600-2100 were also prepared derived from aromatic diamine (4,4'-oxybisbenzenamine, 4,4-ODA), diester of asymmetrical biphenylene diacid (α-BPDE) and monoester of 4-phenylethynylphthalic acid (PEPE) in ethyl alcohol. Then, the TMR solution was mixed with the RDm solution at different weight ratios to afford a series of A-staged thermosetting blend resin (TMR/RDm) solutions for carbon fiber composites. Experimental results demonstrated that the thermosetting blend resins exhibited improved melt processability and excellent thermal stability. After being thermally treated at 200 °C/1 h, the B-staged TMR/RDm showed very low melt viscosities and wider processing window. The minimum melt viscosities of ≤50 Pa·s was measured at ≤368 °C and the temperature scale at melt viscosities of ≤100 Pa·s were detected at 310-390 °C, respectively. The thermally cured neat resins at 380 °C/2 h showed a great combination of mechanical and thermal properties, including tensile strength of 84.0 MPa, elongation at breakage of 4.1%, and glass transition temperature (Tg) of 423 °C, successively. The carbon fiber reinforced polyimide composite processed by autoclave technique exhibited excellent mechanical properties both at room temperature and 370 °C. This study paved the way for the development of high-temperature resistant carbon fiber resin composites for use in complicated aeronautical structures.

Outcomes of a higher calorie inpatient refeeding protocol in Asian adolescents with anorexia nervosa.

OBJECTIVE: This study aims to compare the outcomes of higher calorie refeeding (HCR) and a lower calorie refeeding (LCR) methods among a diverse sample of young Asian adolescents admitted to a tertiary institution in Asia for management of anorexia nervosa (AN). METHOD: This is a retrospective case control study of Asian adolescents who were managed using an inpatient HCR protocol (2016-2017) and an LCR protocol (2010-2014). Baseline characteristics, daily change in percent median body mass index (%mBMI), and rates of refeeding hypophosphatemia were analyzed between groups. RESULTS: A total of 125 adolescents with AN were analyzed with 61 (52%) patients in the HCR group. Mean age was 14.0 years (SD =1.5) and mean presenting %mBMI was 73.2 (SD =6.9) with mean length of stay of 11.9 days (SD = 6.6). Patients in the HCR group had significantly increased rate of change of %mBMI (M = 0.39, SD = 0.31) than patients in the LCR group (M = 0.12, SD = 0.43) (p < .001). There was an increased rate of mild hypophosphatemia in the HCR group (HCR: 46%, LCR: 22%, p = .007) but no difference in rates of moderate hypophosphatemia and no cases of severe hypophosphataemia. Lower presenting %mBMI significantly predicted the phosphate levels (p = .004). DISCUSSION: In a sample of Asian adolescents with AN, use of an HCR protocol was associated with improved rate of inpatient weight gain. There was increased risk of mild hypophosphataemia, but not moderate to severe hypophosphataemia, suggesting that an HCR protocol can be used safely with close monitoring of phosphate levels.

Use of single-question screening for erectile dysfunction: a study of at-risk Asian men in primary health care.

This study assesses the validity of a single-question screener for erectile dysfunction (ED) in men at risk in comparison to a standard validated tool - the five-item version of the International Index of Erectile Function (IIEF-5). A total of 174 men with at least one risk factor for ED were studied, with 58.0% and 10.9% of the study respondents meeting the criteria for their erectile impairment by IIEF-5 and single-question screener respectively. Our results suggest that in spite of high feasibility, a simplified, single-question screener has low sensitivity in capturing ED prevalence, even in an at-risk population, within the Asian context.