The design, formulation, and characterization of new epoxy coatings with built-in chemical and threshold temperature sensors are reported. The materials were prepared by dissolving a chromogenic, fluorescent oligo(p-phenylenevinylene) dye into a cross-linked epoxy resin by reacting monomer/cross-linker/dye mixtures at 180-200 degrees C and quenching the cured polymer to below its glass transition temperature (T(g)). Subjecting these kinetically trapped, thermodynamically unstable molecularly mixed epoxy/dye blends to temperatures above T(g) leads to aggregation of the dye molecules and causes permanent and pronounced changes of their optical absorption and fluorescence properties. Exposure of the materials to selected chemical stimuli, e.g., water, acid, base, and several organic compounds, also causes plasticization of the polymer matrix and leads to irreversible aggregation of dye molecules, concomitant with the pronounced fluorescence and absorption color change. This response is well described by standard kinetic models and can be controlled via the chemical structure and cross-link density of the resin and the dye content.

Background Sarcopenia is a multifactorial loss of muscle mass that can complicate surgical outcomes and increase morbidity and mortality. Parastomal hernias can occur after any surgery requiring stoma formation and is an area of concern as a complication as it can require a second surgery or emergency surgical intervention. Aim To assess the impact of sarcopenia on parastomal hernia formation in the postoperative period. Method A systematic search of publications using MEDLINE, CINAHL, and Cochrane databases was conducted in June 2022. Data were extracted, and a narrative synthesis was undertaken. The Crowe Critical Appraisal Tool (CCAT) assessed the quality of the included studies. The systematic review included original research studies, prospective and retrospective designs, and human studies written in English. Reviews, conference papers, opinion papers, and those including participants < 18 years old were excluded. No restrictions on the date of publication and study setting were applied. Results Nine studies met the inclusion criteria, and these were conducted between 2016 and 2021; 56% (n = 5) used a retrospective study design. The mean sample size was 242.5 participants (SD = ±358.6). No consistent or standardized way of defining sarcopenia or measuring muscle mass was seen between the studies reviewed. However, 45% (n = 4) of the studies reported a significant relationship between sarcopenia and wound healing complications, including an increased incidence of parastomal and incisional hernias. The average CCAT score was 27.56 (SD = ±4.39). Conclusion There is no definitive relationship between sarcopenia and hernia development; however, four studies found a significant relationship between sarcopenia and hernia formation. It must also be considered that different disease processes can cause sarcopenia either through the disease process itself, or the treatment and management. More research and consistent measurements are needed before comparable and consistent outcomes can be compiled.

A novel technique for micronizing polyethylene terephthalate (PET) resin ($ 3 mm) with saturated liquid tetrahydrofuran (THF) has been developed. PET pellets were introduced to a high-pressure vessel filled halfway with THF at loadings up to $ 7 wt % PET. When the vessel was closed and heated, the PET pellets exhibited significant melting point depression at 190 C in saturated liquid THF at 17.1 bar. Although other organic solvents were also able to depress the melting point of PET, only THF was able to facilitate the formation of an emulsion of PET-rich liquid droplets in the saturated liquid solvent when the mixture was agitated. In an attempt to generate the smallest possible PET droplets, a highspeed (5000 rpm), close-clearance, radial flow impeller was used to shear and disperse the droplets at $ 200 C and 20.1 bar. Emulsion was rapidly cooled while mixing. The PET droplets froze at $ 190 C, and the vessel was then cooled to ambient temperature. The excess liquid THF was decanted, and the PET particles were dried in a vacuum oven to remove residual THF. The PET particle sizes ranged between 2 and 70 lm, with number, area, and volume average diameters of 6, 20, and 30 lm, respectively. A comparison between the PET resin and PET powder properties indicated that the micronization reduced the M w from 32,700 to 22,800. DSC results suggest that the rapid quench leads to a morphology different from equilibrium, with small somewhat imperfect crystallites, a lower overall degree of crystallinity, and a suppressed DC p at the glass transition. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 125: [4034][4035][4036][4037][4038][4039][4040] 2012

From a speech at the MBI graduation dinner, Johannesburg, 9 May 1980.