BackgroundEstablishment of the reference interval of thyroid-stimulating hormone (TSH) is critical in the diagnosis of thyroid dysfunction and is affected by age, gender, iodine nutrition, and ethnicity. The aim of this study was to determine the reference intervals of TSH and free thyroxin (FT4) from a large, nationwide data of Korea where iodine intake is more than adequate.MethodsWe analyzed data from the Korea National Health and Nutrition Examination Survey VI that measured serum TSH, FT4, and thyroid peroxidase antibody from 7,061 individuals (urinary iodine measurement in 6,565). Age- and gender-specific reference intervals were established from 95% confidence limits from the 2.5 to 97.5 percentile of TSH (log-transformed) and FT4 in reference populations.ResultsThe geometric mean of TSH was 2.16 ± 0.01 mIU/L, with the lowest value found in the middle aged group (2.04 ± 0.02 mIU/L) and higher values noted in age groups of 10–19 and over 70 years (2.38 ± 0.02 and 2.32 ± 0.07 mIU/L, respectively). The association of TSH and age was U-shaped. The overall reference interval of TSH was 0.59–7.03 mIU/L. Mean FT4 was 1.25 ± 0.003 ng/dL (16.09 ± 0.039 pmol/L), and it showed a small but continuous decrease after 20 years of age (P < 0.001). There was a significant positive correlation between TSH and urine iodine concentration (r = 0.154, P < 0.001).ConclusionsThe reference interval of TSH in Korea, where iodine intake is above the requirement, was 0.59–7.03 mIU/L and showed U-shaped change with age, which was a similar pattern to iodine intake. The reference interval of FT4 was 0.92–1.60 ng/dL. The geometric mean and upper limit of TSH were higher than those of Western populations, reflecting the paramount importance of iodine intake on thyroid function.

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This first nationwide study in Korea demonstrated that the median of UIC and estimated iodine intake lie at nearly 300 µg/L and 250 µg/day, respectively, which shows an overall excellent iodine nutrition.

The SI vibrational predissociation (VP) dynamics and physical characteristics of the p-difluorobenzene-N2(~DFB-Nz) van der Waals complex are reported. The geometry of the complex is roposed to be similar to pDFB ring, and, by analogy to the benzene-NZ complex, with the NZ nearly freely rotating parallel to the aromatic molecular plane. Upper limits to the SI and So van der Waals binding energies of Do' I 240 cm-I and DO" I 213 cm-', respectively, were obtained. Only two of the nine observed SO pDFB ring modes (~6 " the symmetric ring stretch and v< the out-of-plane ring puckering mode) appear to be perturbed by complexation, and these only slightly. In SI, none of the observed ring levels appears significantly perturbed, but surprisingly, spectroscopic evidence concerning Y ( could not be obtained. In general, YS (or Y16a in Wilson notation) is the most perturbed vibration in aromatic-rare gas van der Waals complexes. Vibrational predissociation from four initial SI ring levels lying within the first 800 cm-I of the pDFB-NZ vibrational manifold was characterized using single vibronic level fluorescence spectroscopy. State-to-state dissociation from each level produces the pDFB product molecule in only a few of many accessible SI vibrational levels.Evidence of intramolecular vibration'al redistribution (IVR) within the pDFB-Nz complex is observed for one level. The dissociation is treated by preliminary modeling based on a serial mechanism (involving IVR within the complex followed by VP) that is related to that developed by Kelley and Bernstein [J. Phys. Chem. 1986, 90, 51641 for s-tetrazine-Ar VP. The modeling accounts for the final state selectivity and most but not all of the observed VP channels. The experimental and modeling results are compared with those of the pDFB-Ar complex whose vibrational level structure differs only modestly and in a known way from that of pDFB-N*.

Extreme ultraviolet lithography (EUVL) is a leading-edge technology for pattern miniaturization and the production of advanced electronic devices. One of the current critical challenges for further scaling down the technology is reducing the line-edge roughness (LER) of the final patterns while simultaneously maintaining high resolution and sensitivity. As the target sizes of features and LER become closer to the polymer size, polymer chain conformations and their distribution should be considered to understand the primary sources of LER. Here, we proposed a new approach of EUV photoresist modeling with an explicit description of polymer chains using a coarse-grained model. Our new simulation model demonstrated that interface variation represented by width and fluctuation at the edge of the pattern could be caused by characteristic changes of the resist material during the lithography processes. We determined the effect of polymer chain conformation on LER formation and how it finally contributed to LER formation with various resist material parameters (e.g., Flory–Huggins parameter, molecular weight, protected site ratio, and Tg).