The synthesis and characterization of terminal multiple hydrogen-bonded (MHB) polymers, such as poly(styrene) (PS), poly(isoprene) (PI), and microphase separated PS-b-PI block copolymers, possessing controlled molecular weights and narrow molecular distributions are described. Hydroxyl-terminated polymeric precursors were prepared using living anionic polymerization and subsequent quantitative termination with ethylene oxide. MHB polymers were synthesized in a controlled fashion via end-group modification of these well-defined macromolecular alcohols with excess isophorone diisocyanate and subsequent derivatization of the isocyanate-terminated polymeric intermediate with methyl isocytosine. The glass transition temperatures of the terminal MHB polymers were reproducibly higher than both nonfunctionalized and hydroxyl-terminated polymers at nearly equivalent number average molecular weights. Thin-layer chromatography analysis indicated that the interaction of terminal MHB polymers with silica was stronger as compared to both nonfunctionalized and hydroxyl-terminated polymers. Rheological characterization indicated that the melt viscosity at constant shear rate for various MHB polymers was more than 100 times higher than those for nonfunctionalized and hydroxyl-terminated polymers. Interestingly, the melt viscosity of MHB polymers was higher than those of nonfunctionalized polymers with twice the number average molecular weight. In addition, DSC and rheological characterization also suggested that terminal MHB polymers formed aggregates and not simple dimers in the melt state, and the aggregates were observed to completely dissociate at 80 degrees C.

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Ultraviolet (UV-C) irradiation is a non-thermal disinfection method, effective against a range of bacteria and viruses, which is being considered as an alternative to pasteurization of fruit juices. The objective of this study was to investigate the effect of UV-C irradiation on the polyphenolic content and in-vitro total antioxidant activity of apple juice. UV irradiation doses ranging from 0 to 240 mJ•cm-2 were delivered to apple juice and polyphenols, sugars, in-vitro total antioxidant activity and total phenols were profiled. The results demonstrated that UV-C irradiation in apple juices at relevant commercial disinfection doses induced significant reduction in the concentrations of chlorogenic acid, phloridzin, and epicatechin (p<0.05). The induced changes were relatively minor for the above mentioned polyphenols, except phloridzin (50% reduction) at 240 mJ•cm-2. Epicatechins concentrations were reduced significantly (p<0.05), whereas increase in catechins concentration was observed with increase in UV-C exposure to 240 mJ•cm-2. There was a minor reduction in sugars (glucose and fructose) concentrations with increasing exposure levels from 0-40 mJ•cm-2 (p>0.05). In contrast, a slight increase in sugars concentrations as increase in UV exposure after 40 mJ•cm-2 was observed. These changes were not significantly different from control. Total phenolic content was well retained regardless of the UV exposure for apple juice. In-vitro total antioxidant activity changed when UV exposure exceeded 40 mJ•cm-2 , but remained unchanged at the maximum UV dose of 240 mJ•cm-2. These results suggested that UV-C irradiation could be an effective alternative to conventional thermal processing for production of high quality apple juice. Industrial Relevance This research paper provides scientific evidence of the potential for UV-C irradiation to achieve meaningful levels of disinfection while retaining important bioactive compounds (polyphenols) in apple juice. In-vitro antioxidant activity and individual polyphenols were well retained at commercially relevant doses of 40 mJ•cm-2. From a nutritional perspective, UV-C irradiation is an attractive food preservation technology and offers opportunities for horticultural and food processing industries to meet the growing demand from consumers for healthier food products. Therefore, UV-C irradiated foods could be sold at a premium price to their thermally-processed counterparts, as they have retained their fresh-like properties. This study would provide technical information relevant for commercialization of UV-C treatment of juices.

An online virtual escape-room game was created using the Google Forms survey app for an undergraduate chemistry lab class. Zoom video conferencing service was used to make the activity a collaborative learning experience. The theme was an escape from an abandoned chocolate factory, and the students solved problems to move to the next section or “room” on the Google Forms survey.

An escape-room-game activity was introduced to foster team building and collaborative learning in a laboratoryexperiment setting. The students were placed in a laboratory with clues and puzzles that required the students to use a sequence of analytical instruments in the laboratory in order to escape. The instruments utilized included a UV−vis spectrophotometer, an FTIR spectrometer, a gas chromatograph, and a gas chromatograph−mass spectrometer (GCMS). Student groups solved the puzzles and escaped by identifying a mystery compound at the end of the game. Student surveys indicated that the students enjoyed the lab and that they felt it was an effective review of laboratory techniques.