• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1720-1725
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• 2011

Aspartic acid chelated iron (Asp-Fe) was synthesized by a new method using calcium carbonate, aspartic acid, and ferrous sulfate. This study was carried out to investigate the bioavailability of Asp-Fe in iron-deficient rats. We divided the rats into four experimental groups. The first was the normal diet control group, or NC. The second was the no treated control group of iron-deficient (ID) rats, or ID+C. The third was the heme-iron (heme-Fe) treated group of ID rats, ID+heme-Fe. And the fourth was the Asp-Fe treated group of ID rats, or ID+Asp-Fe. There were no differences among any of the experimental groups in diet consumption, change of body weight, or the weight of the livers, kidneys, or spleens. After 7 days of feeding, the iron content in the sera of the ID+Asp-Fe group (175.2 ${\mu}g$/dL) and the ID+heme-Fe group (140.8 ${\mu}g$/dL) were significantly higher than that of the ID-C group (96.1 ${\mu}g$/dL). The total iron binding capacity (TIBC) of the ID+Asp-Fe group (735.4 ${\mu}g$/dL) was significantly normalized compared to the ID+C group (841.9 ${\mu}g$/dL) or ID+heme-Fe group (824.6 ${\mu}g$/dL). The hematocrit level of the ID+Asp-Fe group was increased to normal levels, but there was no statistical difference among ID groups. The absorption ratio of heme-Fe was 21.3% and that of Asp-Fe was 50.2%, which indicates a 2.3 times higher ratio in comparison with heme iron. With the above results we found that Asp-Fe seems to be an efficient form of iron to supply iron deficient rats in order to cure them of anemia. Thus, these findings suggest that aspartic acid chelated iron has the potential to serve as a functional food related to iron metabolism.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.583-591
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• 2012

Four kinds of makgeolli brewed with different proportions of rice and wheat flour were prepared to investigate the effects of the carbohydrates source on the storage properties, and to examine the chemical characteristics and BA (biogenic amine) contents in makgeolli stored over 30 days at 4, 10 and $20^{\circ}C$, respectively. The chemical properties and BA contents were sustained at a consistent level for those makgeolli stored at $4^{\circ}C$ over 30 days. The alcohol content was significantly higher for makgeolli brewed with higher proportions of rice (R) over wheat flour (WF) (R 100: WF 0, R 70: WF 30) when compared with those brewed with a high proportion of wheat flour (R 30: WF 70, R 0: WF 100), and increased with increasing storage temperature and duration. The free amino acid contents of makgeolli brewed with high proportion of rice were significantly lower under the same conditions. Among the 8 BAs examined, tyramine, putrescine, cadaverine and phenylethylamine were detected, while tyramine and putrescine were mainly detected. Histamine was not detected throughout storage. Makgeolli brewed with rice as the only carbohydrate source exhibited very low levels of total BA during 30 days of storing at $20^{\circ}C$. Total BA contents of R100, R70, R30, R0 were 178.6, 682.9, 1186.7 and 1150.4 mg/L, respectively. These results suggest that makgeolli brewed with relatively higher proportions of rice have better storage properties and are safer for consumption.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.5
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• pp.25-33
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• 2011

This work proposes a skinny-type 10b 50MS/s 0.13um CMOS three-step pipeline ADC for CIS applications. Analog circuits for CIS applications commonly employ a high supply voltage to acquire a sufficiently acceptable dynamic range, while digital circuits use a low supply voltage to minimize power consumption. The proposed ADC converts analog signals in a wide-swing range to low voltage-based digital data using both of the two supply voltages. An op-amp sharing technique employed in residue amplifiers properly controls currents depending on the amplification mode of each pipeline stage, optimizes the performance of op-amps, and improves the power efficiency. In three FLASH ADCs, the number of input stages are reduced in half by the interpolation technique while each comparator consists of only a latch with low kick-back noise based on pull-down switches to separate the input nodes and output nodes. Reference circuits achieve a required settling time only with on-chip low-power drivers and digital correction logic has two kinds of level shifter depending on signal-voltage levels to be processed. The prototype ADC in a 0.13um CMOS to support 0.35um thick-gate-oxide transistors demonstrates the measured DNL and INL within 0.42LSB and 1.19LSB, respectively. The ADC shows a maximum SNDR of 55.4dB and a maximum SFDR of 68.7dB at 50MS/s, respectively. The ADC with an active die area of 0.53$mm^2$ consumes 15.6mW at 50MS/s with an analog voltage of 2.0V and two digital voltages of 2.8V ($=D_H$) and 1.2V ($=D_L$).

• Journal of Nutrition and Health
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• v.53 no.3
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• pp.271-287
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• 2020

Purpose: Variations in the iodine contents of foods is critical for estimating the iodine intake. This study aimed to update the iodine database of common Korean foods and evaluated the iodine intake in Korean adults. Methods: A list of 855 Korean foods was selected for the updated iodine database. The updated database was established with Version 1 and 2 by applying an average or minimum value for the imputed values. The iodine intake was estimated in 5,927 Korean adults using the data from the 2013-2015 Korea National Health and Nutrition Examination Survey. Results: The analytical values in the updated database were 166 (19.4%), followed in order by 318 (37.2%), 247 (28.9%), and 124 (14.5%) for the adapted, imputed, and missing values, respectively. The median of dietary iodine intake was 352.1 ㎍/day (± 2,166.1) and 343.4 ㎍/day (± 2,161.9) in Version 1 and 2 among the total population. The contribution rates of each food group to the iodine intake were 55.7% for seaweeds, which showed a similar trend in Version 2. When subjects were divided by consumption of seaweeds, the median iodine intake was 495.7 ㎍ in the consumer group, which was almost double (241.2 ㎍) that of the non-consumer group. The proportion of subjects who consumed below the Estimated Average Requirement of iodine was 11.0% in the non-consumer group. In contrast, 11.6% in the consumer group of seaweed consumed above the Upper Level of iodine. When the dietary iodine and urinary iodine were examined, the regression coefficient was 0.11718 in Version 1 and 0.11512 in Version 2 after adjusting for age and sex. Conclusion: This study presented the variation of iodine intake in Korean adults by applying different versions of the iodine database. As the iodine intake can vary due to the highly variable concentrations in the major food sources, an iodine database is necessary to be monitored, and caution should be taken when the database is used in research.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.6
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• pp.327-340
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• 2017

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.73-86
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• 2004

In order to estimate the post-ingestion bioavailability of heavy metals and to assess the risk of adverse health effects on human exposure to toxic heavy metals, environmental geochemical surveys were undertaken around the Dogok Au-Ag-Cu and the Hwacheon Au-Ag-Pb-Zn mine sites. Human risk assessment of toxic heavy metals was performed with the results of the SBET(simple bioavailability extraction test) analysis for soil and chemical analytical data for crop plant and water. Arsenic and other heavy metals were highly elevated in tailings from the Dogok(218 As mg/kg, 90.2 Cd mg/kg, 3,053 Cu mg/kg, 9,473 Pb mg/kg, 14,500 Zn mg/kg) and the Hwacheon(72 As mg/kg, 12.4 Cd mg/kg. 578 Pb mg/kg, 1,304 Zn mg/kg) mines. These significant concentrations can impact on soils and waters around the tailing dumps. The quantities of As, Cd and Zn extracted from paddy soils in the Hwacheon mine using the SBET analysis were 55.4%, 20.8% and 26.4% bioavailability, respectively, and for farmland soils in the Dogok mine, 40.8%, 37.6% and 33.0% bioavailability, respectively. From the results of human risk assessment, HI(Hazard Index) value exceeded 1.0 for As in the Hwacheon mine and for Cd in the Dogok mine. Thus, toxic risks for As and Cd exist via exposure(ingestion) of contaminated soil, water and rice grain in these mine sites. The cancer risk for As by the consumption of rice and groundwater in the Hwacheon mine area was 8E-4 and 1E-4, respectively. This risk level exceeds the acceptable risk(1 in 100,000) for regulatory purpose. Therefore, regular ingestion of locally grown rice and ground-water by the local population can pose a potential health threat due to long-term arsenic exposure.

• KDI Journal of Economic Policy
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• v.13 no.1
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• pp.115-134
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• 1991

The role of pension plans in the macroeconomy has been a subject of much interest for some years. It has come to be recognized that pension plans may alter basic macroeconomic behavior patterns. The net effects on both savings and labor supply are thus matters for speculation. The aim of the present paper is to provide quantitative results which may be helpful in attaching orders of magnitude to some of the possible effects. We are not concerned with the providing empirical evidence relating to actual behavior, but rather with deriving the macroeconomic implications for a alternative possibilities. The pension plan interacts with the economy and the population in a number of ways. Demographic variables may thus affect both the economic burden of a national pension plan and the ability of the economy to sustain the burden. The tax transfer process associated with the pension plan may have implications for national patterns of saving and consumption. The existence of a pension plan may have implications also for the size of the labor force, inasmuch as labor force participation rates may be affected. Changes in technology and the associated changes in average productivity levels bear directly on the size of the national income, and hence on the pension contribution base. The vehicle for the analysis is a hypothetical but broadly realistic simulation model of an economic- demographic system into which is inserted a national pension plan. All income, expenditure, and related aggregates are in real terms. The economy is basically neoclassical; full employment is assumed, output is generated by a Cobb-Douglas production process, and factors receive their marginal products. The model was designed for use in computer simulation experiments. The simulation results suggest a number of general conclusions. These may be summarized as follows; - The introduction of a national pension plan (funded system) tends to increase the rate of economic growth until cost exceeds revenue. - A scheme with full wage indexing is more expensive than one in which pensions are merely price indexed. - The rate of technical progress is not a critical element in determining the economic burden of the pension scheme. - Raising the rate of benefits affects its economic burden, and raising the age of eligibility may decrease the burden substantially. - The level of fertility is an element in determining the long-run burden. A sustained low fertility rate increases the proportion of the aged in total population and increases the burden of the pension plan. High fertility has inverse effects.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.290-307
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• 2011

Acrolein is highly toxic and may be formed from carbohydrates, vegetable oils, animal fats and amino acids during heating of food. In the present study, we investigated adults' intake level of cooked meat using high temperature cooking method such as pan frying or grilling directly over an open flame and indirect fire using pan. The 925 adults (438 men and 487 women) participated in this nationwide survey. According to the result of frequency intake of cooked meat at high temperature, the most frequently consumed cooked meat at high temperature was fried chicken, followed by indirect cooking-samgeybsal and directly grilled fish and mackerel pike among twenty five kinds of cooked meats and foods, which were eaten more than three times per month. The woman consumed direct grilled fish and mackerel pike more than three times per month, while the man consumed samgeybsal, pork cutlet, and fried chicken once per week. The order of total intake amount of cooked meat per adult for a year is 10.3 kg of fried chicken (man 13.1 kg, woman 8.04 kg), 6.7 kg of samgeybsal (man 9.4 kg, woman 4.7 kg) and 5.1 kg of jeyukbockeum (man 7.0 kg, woman 3.6 kg). The results of present study suggest that adult must realize the risk of consuming cooked meat at high temperature and the need for education for proper dietary habit to prevent geriatric diseases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.10
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• pp.1324-1330
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• 2009

Lindera obtusiloba Blume (LO), which is widely distributed in Korea, Japan and China, has traditionally been used as a popular folk medicine for the treatment of fever, abdominal pain, bruise and extravation. The purpose of this study was to examine the toxicities of the single and 14-day repeated doses in Sprague-Dawley rats orally administrated with LO at doses of 0, 500, 1000, 2000 (14-day repeated toxicity test) and 5000 (single toxicity test) mg (dry weight)/kg of body weight/day. The results showed that there was no difference in body weight change, food intake, water consumption, or organ weight among different dose groups. Also we observed no death and abnormal clinical signs during the experimental period. Between the groups orally administered LO and the control group, there was no statistical significance in hematological test or serum biochemical values. There were no evidences of histopathological alteration as well as abnormal gross finding mediated by single and 14 days treatments with LO. These results suggest that no observed adverse effect level (NOAEL) of the oral application of LO was considered to be more than 2000 mg/kg in rats under the conditions employed in this study.

• Korean journal of food and cookery science
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• v.23 no.4 s.100
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• pp.423-432
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• 2007

The purpose of this study was to investigate the seasonal variations in water, protein, lipid, ascorbic acid, and ${\beta}-carotene$ contents of 17 vegetables and 4 fruits that are available all the year round and frequently consumed by Koreans. The water contents of the fruits ranged from 83-89%, and the vegetables contained more water than the fruits. The apples and pears had more water in the spring and summer than in the fall and winter. The tangerines showed a high water content in the winter, whereas the strawberries contained more water in the fall. The vegetables also showed seasonal variations in water content. The protein contents of the fruits were lower than 1%; the cucumbers contained 0.1% protein, which was the lowest level, but spinach, lettuce, bean sprouts, sesame leaves, and mushrooms had more than 1% protein. The ascorbic acid and ${\beta}-carotene$ contents of the apples, pears, and tangerines were higher in the fall and winter than in the spring and summer. The vegetables, in general, contained more ascorbic acid than the fruits. The cabbage and radishes showed higher ascorbic acid contents in the fall and winter than in the spring and summer, indicating that vegetables as well as fruits are more nutritious during their harvest season. The zucchini, spinaches, and green peppers had higher ${\beta}-carotene$ contents in the winter than in the other seasons. The above results show that there were seasonal differences in the ascorbic acid and ${\beta}-carotene$ contents of the fruits and vegetables. In addition, the fruits and vegetables had a tendency to contain more ascorbic acid and ${\beta}-carotene$ in the season they were harvested. Therefore, we recommend the consumption of those fruits and vegetables during their harvest season.