• 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.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.3
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• pp.105-112
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• 2011

More accurate evaluation of iodine consumption of Koreans can be made by measuring the urinary iodine excretion of people living in representative areas. The data about average iodine excretions by region, sex and age were gathered in order to suggest as a factor the criteria on the progress or prognosis of thyroid disease patients. This study was conducted on 3,000 subjects (2,000 Younggwang-gun residents and 1,000 Muan-gun residents) between July 2004 and August 2005. The data sampling was done based on stratified random sampling and the data were analyzed according to age (the subjects were divided into age groups, five years each) and sex of the subjects. Of the 3,000 subjects, a total of 1,592 people (1,174 in Younggwang-gun and 418 in Muan-gun) participated in this study, which used ISE (iodine ion selective electrode) to measure the concentration of iodine in urine. The 1,592 subjects are composed of 732 males and 860 females. The average urinary iodine excretion was $3.10{\pm}1.75mg/L$ (0.31~15.2 mg/L). The average iodine excretion of males was $3.09{\pm}1.61mg/L$ (0.42~15.2 mg/L) while it was $3.11{\pm}1.86mg/L$ (0.31~12.5 mg/L) among females, which represents no significant difference between males and females. However, the values were significantly higher than those of Europeans and Americans. There were statistically significant differences among the regions. When the data were analyzed according to age, females in their 40s were found to have a little less urinary iodine excretion and males had less and less iodine excretion as they get older. These results are deemed to have a statistically significant difference. This study was conducted on a large number of people (N=1,592) for the first time in Korea. If the data collected through this study can be regarded as the average urinary iodine excretion of Koreans, it is possible to conclude that the average iodine consumptions of Koreans are a lot more than Europeans and Americans. Thus, the effect of much iodine consumption should be studied further.

• 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.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.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.6
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• pp.785-790
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• 2001

Twelve indigenous male goats, comprising of six intact and six castrated (2.5-3 years; $24.4{\pm}0.62kg$) were assigned evenly into two dietary treatments, viz. $I_0$ and $I_{100}$ and were used to study the effect of supplementation of iodine on the nutrient utilization when their diet contained Leucaena leaf meal. They were offered a conventional concentrate mixture along with Leucaena leucocephala leaf meal, the latter to meet 50% of their crude protein (CP) requirements, and supplemented with either no iodine ($I_0$) or 0.1 mg of iodine ($I_{100}$)/day/animal as potassium iodide for a period of 105 days. Wheat straw given ad libitum was the sole source of roughage. A metabolism trial of 8 days duration was conducted after 90 days of experimental feeding. It was observed that the overall dry matter (DM) intake during experimental period was higher (p<0.05) in $I_{100}$ group as compared to $I_0$ group (508.6 vs. $443.7g\;d^{-1}$). The intake of CP, digestible crude protein (DCP) and metabolisable energy (ME), although non-significant, tended to be higher in the iodine supplemented group, $I_{100}$. Digestibility of dry matter, organic matter (OM), CP, ether extract and crude fiber (CF) did not differ (p>0.05) between the treatments. However, nitrogen retention was higher (p<0.01) in $I_{100}$ than $I_0$ with the values being 2.63 and $1.70g\;d^{-1}$, respectively. No difference (p>0.05) was evident in the retention of calcium and phosphorus between the two groups. The castrated animal exhibited lower DM intake concurrent with higher digestibility of DM and crude fibre (p<0.05), and organic matter and total carbohydrates (p<0.01) when compared to intact ones. It was concluded that supplementation of iodine to leucaena based ration may help in improving the DM intake and nitrogen utilization by goats.

• Korean Journal of Veterinary Research
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• v.6 no.1
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• pp.18-23
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• 1966

The protein-bound iodine-131, the concentration of iodine-131 in blood, and the excretion rate of I-131 through urine and feces were observed in nine Korean native goats, 3 months age, following administration of $3{\mu}C$ of I-131 per kg of body weight. No signiant differences were found due to sex and castration. 1. The average protein-bound iodine-131 conversion ratio of goats was 16.7% in 24 hours. In castrated group, the lowest proteinbound iodine-131 conversion ratio was observed. 2. The average concentration of iodine-131 in bleed, increased very rapidly by 2 hours(4.75%) and rapidly decreased within 6 hours(0.73%). 3. The average excretion rate of I-131 through urine was highest in 24 hours(19.00%) and decreased rapidly within 48 hours(5.32%). 4. The average excretion ration rate of I-131 though feces was highest in 24 hours(2.55%), and decreased slowly.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.633-638
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• 2008

The bunsen reaction, part of IS(Iodine-sulfur) cycle that one of the hydrogen production by the thermochemical water splitting, was investigated. It was observed that $H_2SO_4$ was uniformly generated and generation of $H_2SO_4$ was independent of iodine input. However, generation of HI was decreased with increasing iodine input. It was thought that HI and unreacted iodine were formed complex compound such as $HI_3$ $HI_5$ or $HI_7$. The complex compound accelerated liquid-liquid separation properties in the product. It was also revealed that reaction kinetics was increased with increasing iodine input. Liquid-liquid separation properties were improved with increasing iodine input and reaction temperature. Moreover, no side reaction was occurred at all reaction conditions.

• Journal of Veterinary Clinics
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• v.33 no.5
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• pp.274-277
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• 2016

To determine the concentrations of commercial milks and the effect of different teat dipping methods on iodine concentrations of bulk tank milk, iodine concentration was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The 59 bulk tank milk samples were collected. The 8 brands of commercial whole milk and 5 brands of commercial organic milk were purchased. The iodine concentrations of bulk tank milks of 59 dairy farms were in the range from 42.7 to $562.5{\mu}g/L$. The iodine levels of 4 different teat dipping methods with pre-dipping, post-dipping, pre & post-dipping, and non-dipping were $138.9{\pm}41.1$, $200.6{\pm}106.9$, $205.1{\pm}93.2$, and $110.9{\pm}70.4{\mu}g/L$, respectively. No significant difference (P > 0.05) was observed among 4 different teat dipping methods. Iodine concentrations of commercial whole milks were in the range from 149.1 to $210.4(178.8{\pm}22.0){\mu}g/L$, and iodine concentrations of commercial organic milks were in the range from 85.0 to $356.9(214.2{\pm}123.3){\mu}g/L$. Iodine concentrations of commercial milk in Korea are relatively low comparing with those of other countries.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.3 no.1
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• pp.3-14
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• 2017

Nucleophilic aromatic fluorination has been one of the most explored methods in fluorin-18 based radiochemistry. Unlike electrophilic $[^{18}F]$fluorination methods, no-carrier-added nucleophilic radiofluorination with cyclotron-produced $[^{18}F]$fluoride ion offers better specific radioactivity which is essential aspect to obtain good quality images from positron emission tomography. Contrary to amenable aliphatic radiofluorination, the development of reliable aromatic $[^{18}F]$fluorination methods has been pursued by many research groups; however, no viable method has yet been established. Recently, hypervalent iodine compound draws increasing attention as versatile radiolabeling precursor for various $[^{18}F]$fluoroarenes, since it bears the capacity to introduce fluorine-18 either on electron-deficient or electron-rich aryl ring with enhanced regiospecificity. Other classes of hypervalent iodine congeners often utilized in radiochemistry are iodylarenes, iodonium ylides, and spirocyclic iodonium ylides. Recently developed spirocyclic iodonium ylides have already been avidly employed to provide various $[^{18}F]$aryl fluorides with high labeling efficiency. This metal-free protocol would afford efficient routes, replacing the traditional approaches to $[^{18}F]$fluoroarenes, from prosthetic labeling synthons to complex PET radiotracers.

• Korean journal of food and cookery science
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• v.9 no.4
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• pp.293-297
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• 1993

This study aims to seek ways to improve frying stability of soybean oil which is widely used for deep frying while at the same time attempting to develop new frying oil and fat of high quality. Taking soybean oil as a control group, the study fried frozen potatoes with hydrogenated soybean oil with iodine value ranging from 60 to 110 for 15 hours. The test results showed that in frying stability, hydrogenated soybean oil with iodine value of 87 and 63 was superior to normal soybean oil and hydrogenated soybean oil with iodine value of 111(P<0.05). In sensory evaluation, however, no significant difference can be detected among groups(P>0.05). The correlation between physicoche-mical properties and sensory evaluation results was highest for smoke point and viscosity. This study concludes, therefore, that hydrogenated soybean oil with iodine value of 60~90 is better than normal soybean oil as deep-frying oil.