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Thermoelectric (TE) performance of a specific semicrystalline polymer is studied experimentally only in a limited range of doping levels with molecular doping methods. The doping level is finely controlled via in situ electrochemical doping in a wide range of carrier concentrations with an electrolyte ([PMIM] + [TFSI] - )-gated organic electrochemical transistor system. Then, the charge generation/transport and TE properties of four p-type semicrystalline polymers are analyzed and their dynamic changes of crystalline morphologies and local density of states (DOS) during electrochemical doping are compared. These polymers are synthesized based on poly[(2,5-bis(2-alkyloxy)phenylene)-alt-(5,6-difluoro-4,7-di(thiophene-2-yl)benzo[c][1,2,5]thiadiazole)] by varying side chains: With oligoethylene glycol (OEG) substituents, facile p-doping is achieved because of easy penetration of TFSI - ions into the polymer matrix. However, the charge transport is hindered with longer OEG chains length because of the enhanced insulation. Therefore, with the shortest OEG substituents the electrical conductivity (30.1 S cm -1 ) and power factor (2.88 µW m -1 K -2 ) are optimized. It is observed that all polymers exhibit p- to n-type transition in Seebeck coefficients in heavily doped states, which can be achieved by electrochemical doping. These TE behaviors are interpreted based on the relation between the localized DOS band structure and molecular packing structure during electrochemical doping., (© 2022 Wiley-VCH GmbH.)

This study focuses on the impacts of implementing an online curriculum at a graduate school in South Korea in response to the COVID-19 pandemic. A framework distinguishing impacts to academic, educational, and institutional stakeholders from the virtualization of curricula as well as general COVID-19 prevention measures is invoked to help understand the impacts of these changes. These impacts are sourced from general graduate school operations, course evaluations for two compulsory courses, and unofficial interviews with students and professors. A statistical evaluation of the course evaluations suggested no significant difference between the online format of 2020 and the traditional in person formats in prior years in terms of academics and education. Unofficial meetings with students and faculty revealed technical issues throughout 2020, which many could not be resolved due to the variety of different computer systems at the school as well as limited technical support. Most importantly, students stated they were suffering from prolonged mental and emotional distress such as feeling isolated. Lessons learned include having academic institutions prepare for difficulties in technical support, educational infrastructure investments, compliance, as well as student body mental health.

Soluble glucan, which was obtained from action of glucosyltransferases (GTFs) of Streptococcus mutans on sucrose, was partially hydrolyzed by acetic acid and examined for human T lymphoblast (MOLT-4) stimulating activity. Addition of the partially hydrolyzed glucan (15-60 microg/ml) stimulated human T cell (39-65%) in a dose dependant manner according to MTT assay. Production of interleukine-2 (IL-2) and interleukine-2 receptor (IL-2R) from T cell was increased by 44.5 and 25%, respectively, by addition of partially hydrolyzed glucan (15 microg/ml). These results indicate that stimulation of human T cells by hydrolyzed glucan is probably caused by its effects on stimulating gene expression of IL-2 and IL-2R of human T cell.

The glucan that was produced by glucosyltransferases (GTFs) from Streptococcus mutans was examined for its stimulating functions toward murine peritoneal macrophages. Soluble glucan was obtained by the reaction with cell-free crude GTFs and sucrose, followed by ethanol precipitation, dispersion in water and re-precipitation by ethanol. Soluble glucan, those average molecular weight was about 3 x 10(5), was composed of mixture of alpha-1,6 and alpha-1,3 linkages in a 3:1 ratio. When 30 and 60 microg/ml of the glucan was incubated with peritoneal macrophages, the lysosomal phosphatase activity was increased in a dose-dependent manner, indicating that soluble glucan may activate macrophages. To examine its effects on the various functions of macrophages, soluble glucan was orally administered daily at a level of 100 mg/kg of body weight to C57BL/6 mice. Significant stimulation of the production of H2O2 by the macrophages was observed without any increase in NO production. The production of tumor necrosis factor-alpha (TNF-alpha) by the macrophages was also stimulated from 538.73-555.06 pg/ml to 585.73-596.40 pg/ml during 15 days of oral administration of soluble glucan. The cytotoxicity of peritoneal macrophages against B16 tumor cells was significantly enhanced by 25-38% during 15 days of oral administration. These results may indicate that soluble glucan stimulates the immune functions of macrophages.