RESUMO
Soft body armor is typically comprised of materials such as aramid. Recently, copolymer fibers based on the combination of 5-amino-2-(p-aminophenyl) benzimidazole (PBIA) and PPTA were introduced to the body armor marketplace. The long-term stability of these copolymer fibers have not been the subject of much research, however they may be sensitive to hydrolysis due to elevated humidity because they are condensation polymers. Efforts to evaluate the impact of environmental conditions on fiber strength is very important for the adoption of these materials in armor systems. Three PBIA-based fibers were selected for the study, and were aged at 25 °C, 75 % RH; 43 °C, 41 % RH; 55 °C, 60 % RH; and 70 °C, 76 % RH for up to 524 d. Molecular spectroscopy, scanning electron microscopy, and single fiber tensile testing were performed to characterize changes in their chemical structure, tensile strength, and failure strain as a function of exposure time to different conditions. The fibers were all found to have some reduction in strength at high humidity conditions, with an approximately 14 % reduction for the copolymers and a 29 % reduction for the homopolymer. Molecular spectroscopy revealed some changes which suggest that hydrolysis of the benzimidazole ring is occurring at these elevated temperatures, possibly explaining the observed change in strength.
RESUMO
Apprehension in taking independent care of children with medical devices may lead to unnecessary visits to the ED and/or acute clinic (AC). To address these concerns, our institution implemented a gastrostomy tube (GT) class in 2011 for caretakers. We hypothesized that inappropriate GT-related ED/AC visits would be lower in preoperatively educated caregivers. We performed a retrospective cohort study of all patients aged 0 to 18 who received GT (surgical or percutaneous) at our institution between 2006 and 2015 (n = 1340). Class attendance (trained vs untrained) and unscheduled GT-related ED/AC visits one year after GT placement were reviewed. Gastrostomy-related ED/AC visits were classified as appropriate (hospital-based intervention) or inappropriate (site care and education/reassurance). Occurrence of ED/AC visits was compared between trained and untrained cohorts. We found that 59 per cent of patients had an unscheduled GT-related ED/AC visit within one year of placement. The trained cohort had 27 per cent less unplanned ED/AC visits within one year (mean 1.21 (SD 1.82) vs untrained 1.65 (2.24), P < 0.001). On multivariate analysis, GT education independently decreased one-year GT-related health care utilization (Odds Ratio 0.75, 95% Confidence Interval 0.59-0.95). Formal education seems to decrease GT-related health care utilization within one year of placement and should be integrated into a comprehensive care plan to improve caregiver self-efficacy.
