• Journal of Nutrition and Health
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• v.44 no.1
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• pp.82-91
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• 2011

The present study reviewed the effects of excess iodine intake on thyroid function and the incidence of thyroid disease and discussed the scientific basis for establishing a tolerable upper intake level (UL) of iodine for Koreans. ULs are defined as "the highest level of daily nutrient intake that is likely to pose no risk of adverse effects to almost all individuals in the general population." Koreans consume excess iodine from seaweed, and iodine intake is strongly influenced by seaweed consumption. However, no dose-response data derived from subjects consuming excess iodine frequently but not continuously during a lifetime are available. Therefore, the Korean DRI committee set the iodine UL to reduce the risk of adverse health effects by excess iodine intake for Koreans with distinctive seaweed-eating habits.

• Journal of Nutrition and Health
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• v.45 no.3
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• pp.218-228
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• 2012

The prevalence rate of thyroid dysfunction (hypothyroidism and hyperthyroidism) has increased within the Korean population and seems to be affected by iodine dietary habits. Some studies reported that the prevalence of thyroid dysfunction increase both in the area of iodine deficiency and excess. In this study, we tried to discover the difference in iodine intake, anthropometric measurements, and blood parameters between male subjects with or without subclinical thyroid dysfunction. A total of 5,249 subjects (Euthyroid: 4706, SubHypo: 454, SubHyper: 89) were used in this study. There were no significant differences in BMI, body fat, visceral fat, waist circumference, SBP, DBP, total cholesterol, HDL-cholesterol, LDL-cholesterol, TG, fasting serum glucose, HbA1c, alcohol intake, however significant differences were noticed in both age and smoking status. Through a food frequency questionnaire (FFQ), iodine intake per day was estimated. The average iodine intake was similar (SubHypo $392.9{\pm}279.0{\mu}g$, Euthyroid $376.5{\pm}281.7{\mu}g$, SubHyper $357.3{\pm}253.8 {\mu}g$) among groups. The main source of iodine intake was eggs (52.8%, 54.2%, 52.4%) followed by milk (16.3%, 15.8%, 17.8%), then sea mustard & sea tangle (12.4%, 11.9%, 11.6%). The prevalence of subclinical hypothyroidism and subclinical hyperthyroidism was higher in subjects whose intake was higher than the recommended nutrient intake (RNI). These results suggest that the excess consumption of iodine intake may act as one of the risk factors regarding thyroid dysfunction in Korea. Therefore, an adequate amount of iodine intake is necessary in order to prevent subclinical thyroid dysfunction and clinical thyroid dysfunction.

• Korean Journal of Community Nutrition
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• v.27 no.6
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• pp.503-514
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• 2022

Objectives: This study examines the status of iodine intake and compares the characteristics (region and thyroid disease prevalence) according to the iodine-sourced food intake pattern in Chinese adults. Methods: An online survey was conducted by enrolling 437 Chinese adults aged 18-65 years, living in three regions with different iodine nutritional statuses: Sichuan, Chongqing, and Guangdong. Results: The prevalence of thyroid diseases in Sichuan, Chongqing, and Guangdong were 12.5%, 8.5%, and 2.8%, respectively. Conversely, the proportion of people who received thyroid disease-related examinations was a mere 37.5%. Among the subjects who underwent thyroid examination, the prevalence of thyroid disease in the three regions was 32.2%, 21.8%, and 8.0%, respectively. No differences were obtained in the total iodine intake by region, but the type of iodine source foods differed. Regardless of the region, the highest iodine content was obtained from seaweed. However, the iodine content from iodized salt and other foods differed significantly by region. Factor analysis revealed three food intake patterns according to the iodine food source. The study further determined regional differences and differences in the prevalence of thyroid disease according to food intake patterns. Conclusions: High salt intake can also increase iodine intake, which is thought to have an effect on the occurrence of iodine-excess thyroid disease. Hence, efforts focused on improving salty eating habits need to be implemented.

• Journal of Nutrition and Health
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• v.30 no.10
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• pp.1195-1202
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• 1997

Iodine-rich seaweed soup has been traditionally supplied to postpartum women in Korea. This dietary habit might introduce over-intake of iodine above the recommended requirements, and might provoke postpartum thyroid dysfunction. Although the response to excess iodine intake is highly variable, goiter, hyperthyroidism, hypothyroidism, and thyroiditis could follow the daily intake of 1,500$\mu\textrm{g}$ of iodine. A few studies are available concerning iodine toxicity in Korea. The purpose of this study was to investigate the relationships between the dietary intake of iodine and thyroid function change as well as the incidence of postpartum thyroiditis. One hundred and thirty-seven postpartum women who had experienced normal deliveries were studied. Dietary intake of iodine and excretion concentration of iodine in breast milk and maternal urine were measured . Serum T$_3$, T$_4$, TSH, anti-thyroglobulin antibody, and anti-microsomal antibody were anlayzed 1 week before delivery and 1, 6, 12, and24 weeks after delivery. Iodine intake was analyzed by one-to-one interviews using 24-hr recall and a food frequncy questionnaire. The result showed that the intake of dietary iodine before delivery and 1 and24 weeks after delivery were 483$\mu\textrm{g}$/day, 3367$\mu\textrm{g}$/day, and 1069$\mu\textrm{g}$/day, respectively. The concentration of iodine in urine at the first week after delivery was 63$\mu\textrm{g}$/dL, and 23.9$\mu\textrm{g}$/dL in breast milk . The levels of serum T$_3$ and T$_4$ before delivery were 2.01ng/mL and 11.49$\mu\textrm{g}$U/dL, respectively, showing that the levels were gradually dropping to normal values after delivery. Positive serum anti-thyroglobulin antibody and anti-microsomal antibody appeared in 3 cases. After a 24 week follow-up period , 6 women(10.3%) experienced cases of postpartum thyroiditis, 5 of which were cases of hyperthyroidism and one of which was a case of hypothyroidism. These figures of postpartum thyroiditis are similar to those of other countries.

• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.51-56
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• 2008

The regioselective ring opening of epoxides using elemental iodine and bromine in the presence of methimazole (MMI, a anti-thyroid drug) and its metabolite methimazole-disulfide as new catalysts are studied. MMI easily converted in vitro to MMI-disulfide without any double activation presented in vivo. FT-Raman and UV spectroscopies are used to study the interaction of iodine with these catalysts. The results indicate that both catalysts are efficient in polyiodide formation, but MMI-disulfide can catalyze this reaction in higher yield and regioselectivity. The complex [(MMI-disulfide)I]+.I3- is considered to be formed initially which could be bulkier by addition of excess of iodine in the course of the reaction. These bulky nucleophiles have a fundamental role in the high regioselectivity by attacking the less sterically hindered epoxide carbon. In this study we suggest that MMI is readily converted to MMI-disulfide by interaction with iodine or activated iodine in thyroid gland, and this process is responsible for high anti-thyroid activity of MMI.

• Journal of the Korean Chemical Society
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• v.19 no.5
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• pp.339-342
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• 1975

The rates of consumption of iodine and gas evolution in hydrazine-iodine reaction in the presence of large excess of hydrazine have been studied in the pH range 0.5${\sim}$7. They are the same at very low pH and both increase to respective asymptotic values as pH is increased. The rate of iodine consumption is three orders of magnitude faster than the rate of gas evolution at higher pH. The results are explained by postulating that $N_2H_4$ but not protonated form reacts with iodine and an intermediate, probably $N_2H_2I_2$, is formed which decomposed by first order reaction of rate constant about 1.5${\times}10^{-3}sec^{-1}$ in neutral and weakly acidic solutions.

• Journal of Ginseng Research
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• v.8 no.2
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• pp.167-171
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• 1984

Soft X-ray is useful to identify the quality of fresh ginseng causing the inside cavity or white pan of red ginseng. The portion of low mass density identified by the difference in absorption of soft X-ray showed lower dry matter density and less or no response to iodine test indicating less accumulation or excess consumption of starch. The inside white part of red ginseng absorbed less X-ray than the normal part did. Probability for identification of the inside cavity or white at fresh ginseng was rather high (80-90%) in screen observation than f'3m reading and seemed to be increased further by using the developed screen and with training. The inside white of red ginseng appeared to be due to starch deficiency. Dry matter density appeared to be better than fresh weight density for the quality criterion.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.28-34
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• 2018

Purpose With regard to the use of radioiodine in domestic medical institution, the case of exceeding the allowance of nuclear safety Act about radioactive concentration in drainage was found. Through understanding the cause of exceeding case and analyzing radioactive concentration in drainage, evaluating the relationship of the public waters in surroundings and usefulness. Materials and Methods From November 1, 2014 to April 30th, 2015, the research is aiming at domestic twenty hospitals for six months. By using a HPGe gamma-ray spectrometer(Canberra DSA-1000) and GENIE-2000 Analysis software for comparative analysis, measuring a radioactive concentration of radioiodine in drainage. Consequently, we confirm the excess of radioactive concentration of radioiodine in seven medical institutions. Results Conducting a survey of twenty hospitals and average radioactive concentration of radioiodine in drainage appears $42,100Bq/m^3$. The features of domestic hospitals where show a high radioactive concentration are a number of medical treatment patient when using radioactive iodine and the absence of private rest room. During I-131 whole body scan, the pretreatment procedure of urinating is considered emission of residual Iodine. In public waters, the cause of exceeding detect on radioactive concentration in drainage suppose a diagnostic radioactive iodine. Conclusion We confirm the importance of enhanced education, providing a safety control instructions and installing a private rest rooms for patients who injected a low capacity radioiodine. Also, constructing institutional and legal management system is considered about the Emission management standard in drainage.

• Korean Journal of Animal Reproduction
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• v.9 no.2
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• pp.133-139
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• 1985

An immunoassay may be defined as an analytical procedure involving the competitive reaction between a limiting concentration of specific antibody and two populations of antigen, one of which is labelled or immobillized. The advent of immunoassay has revolutionised our knowledge of reproductive physiology and the practice of veterinary and clinical medicine. Radioimmunoassay (RIA) was the first of these methods to be developed, which meausred the analyte with good sensitivity, accuracy and precision (1,2). The essential components of RIA are:-(i) a limited concentration of antibodies, (ii) a reference preparation, and (iii) an antigen labelled with a radioisotope (usually tritium or iodine-125). Most procedures invelove isolating the antibody-bound fraction and measuring the amount of labelled antigen. Good facilities are available for scintilltion counting, data reduction nd statistical analysis. RIA is undergoing refinement through:-(i) the introduction of new techniques to separate the antibody-bound and free fractions which minimize the misclassification of labelled antigen into these compartments, and the amount of non-specfic binding. (3), (ii) the development of non-extration for the measurement of haptens (4), (iii) the determination of a, pp.rent free (i.e. non-protein bound) analytes (5), and (iv) the use of monoclonal antibodies(6). In 1968, Miles and Hales introduced in important new type of immunoassay which they termed immunora-diometric assay (IRMA) based on t도 use of isotopically labelled specific antibodies(7) in a move from limited to excess reagent systems. The concept of two-site IRMAs (with a capture antibody on a solid-phase, and a second labelled antibody to a different antigenic determinant of the analyte) has enabled the development of more sensitive and less-time consuming methods for the measurement of protein hormones ovar wide concentration of analyte (8). The increasing use of isotopic methos for diverse a, pp.ications has exposed several problems. For example, the radioactive half-life and radiolysis of the labelled reagent limits assay sensitivity and imposes a time limit on the usefulness of a kit. In addition, the potential health hazards associated with the use and disposal of radioactive cmpounds and the solvents and photofluors necessary for liquid scientillation counting are incompatable with the development of extra-laboratory tests. To date, the most practical alternative labels to radioisotopes, for the measurement of analytes in a concentration > 1 ng/ml, are erythrocytes, polystyrene particiles, gold sols, dyes and enzymes or cofactors with a visual or colorimetric end-point(9). Increased sensitivity to<1 pg/ml may be obtained with fluorescent and chemiluminescent labels, or enzymes with a fluorometric, chemiluminometric or bioluminometric end-point. The sensitivity of any immunoassay or immunometric assay depends on the affinity of the antibody-antigen reaction, the specific activity of the label, the precision with which the reagents are manipulated and the nonspecific background signal (10). The sensitivity of a limited reagent system for the measurement of haptens or proteins is mainly dependent upon the affinity of the antibodies and the smalleest amount of reagent that may be manipulated. Consequently, it is difficult in practice to improve on the sensitivity obtained with iodine-125 as the label. Conversely, with excess reagent systems for the measurement of proteins it is theoretically possible to increase assay sensitivity at least 1000 fold with alternative luminescent labels. To date, a 10-fold improvement has been achieved, and attempts are being made to reduce the influence of other variables on the specific signal from the immunoreaction.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1099-1109
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• 2020

The performance of gadolinium burnable absorber (GdBA) for reactivity control in UO₂ and (U, Th)O₂ fuels and its impact on spent fuel characteristics was performed. Five fuel assemblies: one without GdBA fuel rod and four each containing 16, 24, 34 and 44 GdBA fuel rods in both fuels were investigated. Reactivity swing in all the FAs with GdBA rods in UO₂ fuel was higher than their counterparts with similar GdBA fuel rods in (U, Th)O₂ fuel. The excess reactivity in all FAs with (U, Th)O₂ fuel was higher than UO₂ fuel. At the end of single discharge burn-up (~ 49.64 GWd/tHM), the excess reactivity of (U, Th) O₂ fuel remained positive (16,000 pcm) while UO₂ fuel shows a negative value (-6,000 pcm), which suggest a longer discharge burn-up in (U, Th)O₂ fuel. The concentration of plutonium isotopes and minor actinides were significantly higher in UO₂ fuel than in (U, Th)O₂ fuel except for ²³⁶Np. However, the concentration of non-actinides (gadolinium and iodine isotopes) except for ¹³⁵Xe were respectively smaller in (U, Th)O₂ fuel than in UO₂ fuel but may be two times higher in (U, Th)O₂ fuel due to its potential longer discharge burn-up.