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Department of Industrial Engineeringclos

Optically Transparent 1-D EBG Antenna Using Sub-Skin Depth Thin-Film Alloy in the Ka-Band

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Sex, menopause, and age differences in the associations of persistent organic pollutants with thyroid hormones, thyroxine-binding globulin, and peripheral deiodinase activity: A cross-sectional study of the general Korean adult population

Persistent organic pollutants (POPs) can disrupt the thyroid hormone system in humans. We assessed the associations of several POPs with serum thyroid hormones (T3 and T4) and thyroid-stimulating hormone, and investigated the modulating effects of sex, menopausal status, and age on these associations, in a subgroup of the adult population (n = 1250) from the Korean National Environmental Health Survey. PCB105 and PCB118 were negatively associated with total T4 in premenopausal females and males aged < 50, whereas the associations were insignificant in other groups. PCB180, p,p'-DDE, and p,p'-DDT showed positive associations with total T3 in postmenopausal females; however, among males aged > 50, PCB118, PCB138, and p,p'-DDE showed negative associations with total T3. The effects of exposure to multiple POPs were examined in multi-factor analyses. Factor 2 comprised PCB52, hexachlorobenzene, and BDE-47 was associated with an increase in free T4 in premenopausal females (beta = 0.015, p = 0.024), while Factor 1, which contained most POPs, was associated with a change in total T3 in postmenopausal females (beta = 0.032, p = 0.040) and males aged >= 50 (beta =-0.039, p = 0.023). Changes in total T4 or total T3 could be explained by differences in thyroxine-binding globulin (TBG) and peripheral deiodinase activity (G(D)). Negative associations of TBG with PCB105 in premenopausal females and PCB153 in males aged < 50 may mediate the effect of decreasing total T4. PCB180, p,p'-DDE, p,p'-DDT, and Factor 1 were positively associated with G(D), which is consistent with an increased total T3 in postmenopausal females. PCB118 was negatively associated with G(D) and total T3 in males aged >= 50. BDE-47 and beta-hexa-chlorocyclohexane were associated with thyroid autoantibodies in premenopausal females and males aged < 50. Our observations suggest that the thyroid-disrupting effects of POPs may differ by sex, sex hormonal status, and age, and may be mediated by TBG and G(D).N

Vertical Alignments of Graphene Sheets Spatially and Densely Piled for Fast Ion Diffusion in Compact Supercapacitors

Supercapacitors with porous carbon structures have high energy storage capacity. However, the porous nature of the carbon electrode, composed mainly of carbon nanotubes (CNTs) and graphene oxide (GO) derivatives, negatively impacts the volumetric electrochemical characteristics of the supercapacitors because of poor packing density (<0.5 g cm^–3). Herein, we report a simple method to fabricate highly dense and vertically aligned reduced graphene oxide (VArGO) electrodes involving simple hand-rolling and cutting processes. Because of their vertically aligned and opened-edge graphene structure, VArGO electrodes displayed high packing density and highly efficient volumetric and areal electrochemical characteristics, very fast electrolyte ion diffusion with rectangular CV curves even at a high scan rate (20 V/s), and the highest volumetric capacitance among known rGO electrodes. Surprisingly, even when the film thickness of the VArGO electrode was increased, its volumetric and areal capacitances were maintained