• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.225-233
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• 2020

By the standards and specifications for hygiene products, three test methods for formaldehyde are specified for each item type of hygiene product. After derivatization using acetylacetone and 2,4-dinitrophenylhydrazine (2,4-DNPH), formaldehyde is analyzed by spectrophotometer and high-performance liquid chromatography (HPLC). Validation of the three test methods was performed on tissue, diaper lining and waterproof layer, and panty liner products. The results of linearity (R²), limit of detection (LOD), limit of quantification (LOQ), recovery rate (%) and reproducibility (%), showed that all three methods are suitable for analyzing formaldehyde in hygiene products. After derivatization with 2,4-DNPH and cetylacetone, formaldehyde was analyzed at 0, 3, 6, 9, 24 and 48 hours by HPLC. Formaldehyde derivatized with 2,4-DNPH showed no statistically significant change in formaldehyde peak area over time (P>0.05). But, acetylacetone-derivatizated formaldehyde showed a negative correlation coefficient (r) over time (P<0.01). We investigated the residual amounts of formaldehyde in 205 hygiene products distributed in Busan. Among 74 disposable diaper products tested, 73 had low concentrations of formaldehyde (0.13-29.87 mg/kg). Moreover, formaldehyde was not detected in any of 78 tissue, 27 disposable paper towel, 12 disposable dishcloth, 7 paper cup, one brand of paper straw and 6 disposable napkin products.

• Korean Journal of Remote Sensing
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• v.27 no.5
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• pp.613-623
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• 2011

This study assessed the feasibility to apply Two-band and Three-band reflectance models for chlorophyll-a estimation in turbid productive waters whose scale is smaller and narrower than ocean using a high spatial resolution image. Those band ratio models were successfully applied to analyzing chlorophyll-a concentrations of ocean or coastal water using Moderate Imaging Spectroradiometer(MODIS), Sea-viewing Wide Field-fo-view Sensor(SeaWiFS), Medium Resolution Imaging Spectrometer(MERIS), etc. Two-band and Three-band models based on band ratio such as Red and NIR band were generally used for the Chl-a in turbid waters. Two-band modes using Red and NIR bands of RapidEye image showed no significant results with $R^2$ 0.38. To enhance a band ratio between absorption and reflection peak, We used red-edge band(710 nm) of RapidEye image for Twoband and Three-band models. Red-RE Two-band and Red-RE-NIR Three-band reflectance model (with cubic equation) for the RapidEye image provided significance performances with $R^2$ 0.66 and 0.73, respectively. Their performance showed the 'Approximate Prediction' with RPD, 1.39 and 1.29 and RMSE, 24.8, 22.4, respectively. Another three-band model with quadratic equation showed similar performances to Red-RE two-band model. The findings in this study demonstrated that Two-band and Three-band reflectance models using a red-edge band can approximately estimate chlorophyll-a concentrations in a turbid river water using high-resolution satellite image. In the distribution map of estimated Chl-a concentrations, three-band model with cubic equation showed lower values than twoband model. In the further works, quantification and correction of spectral interferences caused by suspended sediments and colored dissolved organic matters will improve the accuracy of chlorophyll-a estimation in turbid waters.

• Journal of radiological science and technology
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• v.32 no.3
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• pp.299-306
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• 2009

Purpose : To compare radiation dose for coronary CT angiography (CTA) obtained with 6 examination protocols such as a retrospectively ECG gated helical scan, a prospectively ECG gated sequential scan, low kVp technique, and cardiac dose modulation technique. Materials and Methods : Coronary CTA was performed by using 6 current clinical protocols to evaluate effective dose and organ dose in primary beam area with anthropomorphic female phantom and glass dosimetric system in 64 channel multi-detector CT. After acquiring topograms of frontal and lateral projection with 80 kVp and 10 mA, main coronary scan was done with 0.35 sec tube rotation time, 40 mm collimation ($0.625\;mm{\times}64\;ea$), small scan field of view (32 cm diameter), 105 mm scan length. Heart beat rate of phantom was maintained 60 bpm in ECG gating. In constant mAs technique 120 kVp, 600 mA was used, and 100 kVp for low kVp technique. In a retrospectively ECG gated helical CT technique 0.22 pitch was used, peak mA (600 mA) was adopted in range of $40{\sim}80%$ of R-R interval and 120mA(80% reduction) in others with cardiac dose modulation. And 210 mAs was used without cardiac dose modulation. In a prospectively ECG gated sequential CT technique data were acquired at 75% R-R interval (middle diastolic phase in cardiac cycle), and 120 msec additional padding of the tube-on time was used. For effective dose calculation region specific conversion factor of dose length product in thorax was used, which was recommended by EUR 16262. Results : The mean effective dose for conventional coronary CTA without cardiac dose modulation in a retrospectively ECG gated helical scan was 17.8 mSv, and mean organ dose of heart was 103.8 mGy. With low kVp and cardiac dose modulation the mean effective dose showed 54.5% reduction, and heart dose showed 52.3% reduction, compared with that of conventional coronary CTA. And at the sequential scan(SnapShot pulse mode) under prospective ECG gating the mean effective dose was 4.9 mSv, this represents an 72.5% reduction compared with that of conventional coronary CTA. And heart dose was 33.8 mGy, this represents 67.4% reduction. In the sequential scan technique under prospective ECG gating with low kVp the mean effective dose was 3.0 mSv, this represents an 83.2% reduction compared with that of conventional coronary CTA. And heart dose was 17.7 mGy, this represents an 82.9% reduction. Conclusion : In coronary CTA at retrospectively ECG gated helical scan, cardiac dose modulation technique using low kVp reduced dose to 50% above compared with the conventional helical scan. And the prospectively ECG gated sequential scan offers substantially reduced dose compared with the traditional retrospectively ECG gated helical scan.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.742-748
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• 2009

In the meat industry, correct breed information in food labeling is required to assure meat quality. Genetic markers provide corroborating evidence to identify breed. We described the development of DNA markers to discriminate between Korean beef cattle (Hanwoo), Holstein, and mixed cow beefs. As most breeds are standardized for coat colour, the melanocortin 1 receptor (MC1R) gene, involved in the regulation of eu/pheomelanins synthesis, has been suggested as marker for breed traceability of products of animal origin. We also designed sex-determining region Y (SRY) gene specific primers for Y chromosome detection. In this study, fragments of MC1R gene and SRY gene were amplified by multiplex-PCR and subjected to digestion by MspA1I restriction endonuclease. Reaction products were analysised by denaturing high performance liquid chromatography (DHPLC). As a result, we identified 6 DHPLC peak types from MC1R gene and SRY gene analysis. DHPLC method showed more sensitive than RFLP method for DNA fragments analysis. Therefore, DHPLC method can apply to identify for Hanwoo, Holstein and mixed beef.

• Journal of the Korean Magnetics Society
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• v.13 no.5
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• pp.187-192
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• 2003

The magnetic and thermal properties of NiFe/[IrMn-Mn]/CoFe with Mn additions have been studied. As-deposited CoFe pinned layers with [IrMn-Mn]layer had dominantly larger exchange biasing field ( $H_{ex}$) and blocking temperature ( $T_{b}$) than those with pure I $r_{22}$M $n_{78}$ used. The $H_{ex}$ and $T_{b}$ improved with 76.8-78.1 vol% Mn, but those of the NiFe/IrMn/CoFe dropped considerably with more addition of 0.6 vol % Mn. The average x-ray diffraction peak ratios of fcc [(111)CoFe, NiFe]/(111)IrM $n_3$ textures for the Mn inserted total vol of 75.5, 77.5, and 79.3% were about 1.4, 0.8, and 0.6, respectively. For the sample without Mn inserted layer, the $H_{ex}$ between IrMn and CoFe layers was almost zero, but it increased to 100 Oe after annealing of 250 $^{\circ}C$. For as-grown two multilayers samples with ultra-thin Mn layers of 77.5 and 78.7 vol %, the $H_{ex}$s were 259 and 150 Oe, respectively. In case of IrMn with 77.5 vol% Mn, the $H_{ex}$ was increased up to 475 Oe at 350 $^{\circ}C$ but decreased to 200 Oe at 450 $^{\circ}C$, respectively. The magnetic properties and thermal stabilities of NiFe/[IrMn-Mn]/CoFe multilayer were enhanced with Mn additions. In applications where higher $H_{ex}$ and $T_{b}$ are required, proper contents of Mn can be used. be used. used.

• The Korean Journal of Mycology
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• v.1 no.1
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• pp.3-11
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• 1973

Four species of nematodes attacking mushroom beds were found in samples taken from 35 mushroom farms throughout Korea. These were Rhabditis sp., Aphelenchoides sp., Ditylenchus sp. and Aphelenchus sp. ,Rhabditis sp. was found from compost and casing from all mushroom farms and the frequencies of Aphelenchoides sp. was 31.4% in the both compost and casing. Both Ditylenchus sp. and Aphelenchus sp. showed 2.7% of frequencies in the compost, none in casing. Temperature and moisture content of compost affected pathogenicity of Aphelenchoides sp. on mushroom mycelia grown in compost. The higher temperature and moisture content the sooner the damage became apparent, and the more rapid was subsequent destruction of mycelia. There was no mycelial destruction at the lowest temperature of $10^{\circ}C$. Rhabditis sp. completely disintegrated mycelia grown in the compost, in the early stage, the numbers of Rhabditis sp. rose gradually and then increased suddenly to reach a peak but soon declined. At first, the pH of Rhabditis-infested spawned compost declined but then rose gradually as mycelia was disintegrated by nematodes. The trend in pH of infested unspawned compost was similar to those of uninfested, unspawned compost. Cultures inoculated with surface-disinfected dead Rhabditis sp. and with tap water used in the nematode extraction procedures showed no mycelial injury associated microorganisms containing within or outside the nematodes even though added by artificial wounding of the mycelia. Cultures artificially wounded showed no injury away from the wounds without the presence of living Rhabditis sp., such wounded mycelia slowly regenerated. On the other hand, artificial wounding accelerated the breakdown of mycelia in the presence of living Rhabditis sp.

• Clinical and Experimental Pediatrics
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• v.48 no.3
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• pp.298-305
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• 2005

Purpose : We performed this study to evaluate the mean serum levels of insulin-like growth factor (IGF)-I, insulin-like growth factor binding protein(IGFBP)-2 and IGFBP-3 in healthy Korean children according to age and sex. Methods : Ninety two healthy children, consisting of 42 boys and 50 girls, were classified into five groups according to age : neonate; infancy; early childhood; late childhood; and adolescence. We measured serum levels of IGF-I, IGFBP-2 and IGFBP-3 by enzyme-linked immunosorbent assay(ELISA) and analysed the serum levels according to sex and age group. Results : For boys, the mean serum levels of IGF-I(ng/mL) in neonate, infancy, early childhood, late childhood and adolescence were $41.1{\pm}3.6$, $70.9{\pm}33.7$, $103.5{\pm}97.2$, $89.8{\pm}46.5$ and $51.4{\pm}27.8$, respectively. Those of IGFBP-2(ng/mL) were $8.2{\pm}3.4$, $5.8{\pm}0.4$, $9.3{\pm}4.0$, $9.5{\pm}1.1$ and $7.0{\pm}0.5$, respectively. Those of IGFBP-3(ng/mL) were $559.2{\pm}215.2$, $1,333.3{\pm}692.5$, $2,254.6{\pm}1,513.8$, $2,447.1{\pm}1,464.2$, $1,533.6{\pm}807.4$, respectively. For girls, the mean serum levels of IGF-I(ng/mL) according to five age groups were $53.3{\pm}9.5$, $99.3{\pm}45.8$, $69.6{\pm}51.1$, $106.2{\pm}67.0$ and $145.1{\pm}127.8$, respectively. Those of IGFBP-2 (ng/mL) were $9.1{\pm}7.4$, $5.3{\pm}0.9$, $6.9{\pm}2.0$, $10.5{\pm}3.0$ and $7.9{\pm}1.3$, respectively. Those of IGFBP-3(ng/mL) were $858.2{\pm}433.4$, $1,834.8{\pm}851.3$, $1,404.3{\pm}570.2$, $2,203.5{\pm}899.4$ and $2,029.3{\pm}1,316.7$, respectively. There were significant positive correlations observed between IGF-I and IGFBP-3 levels(r=0.589, P=0.000). Conclusion : IGF-I and IGFBP-3 levels increased as children get older. The peak level of IGFBP-3 was observed in late childhood for both boys and girls, suggesting a current trend of children reaching peak growth velocity before adolescence. The IGFBP-2 level was higher in neonates compare to infancy, suggesting that IGFBP-2 is an important substance for fetal growth.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.428-438
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• 1995

The gelatinization properties of corn and waxy corn starch doughs were examined at various moisture contents, heating temperatures and heating times. The onset temperatures of gelatinization with 1% CMC using Brabender Amylograph were $64^{\circ}C$ for both corn and waxy corn starch. In the gelatinization properties using DSC, onset temperature$(T_o)$, maximum peak temperature$(T_p)$, completion temperature$(T_c)$ and enthalpy of the corn starch were $68.15^{\circ}C,\;74.01^{\circ}C,\;85.65^{\circ}C$ and $3.2\;cal/gram$ respectively. While those of the waxy corn starch were $68.24^{\circ}C,\;75.43^{\circ}C,\;93^{\circ}C$ and $4.2\;cal/gram$ respectively. In enzymatic analysis, when the moisture content increased from 36% to 52% and heating temperature from $60^{\circ}C$ to $100^{\circ}C$, the gelatinization degree of starch dough increased from about 10% to about 62%. The gelatinization degree of waxy corn starch dough was $15{\sim}20%$ higher than that of corn starch dough under the same gelatinization conditions. The regression equations of gelatinization degree (Y) of starch dough in the range of $36{\sim}52%$ moisture content $(X_1)\;60{\sim}100^{\circ}C$ heating temperature $(X_2)\;and\;0{\sim}2.0$ min heating time $(X_3)$ were examined using response surface analysis. The regression equation of corn starch dough was: $Y=28.659+8.638\;X_}+15.675\;X_2+7.770\;X_3-1.620\;{X_1}^2+10.790\;X_1X_2-4.220\;{X_2}^2+0.510\;X_1X_3+1.980\;X_2X_3-6.850\;{X_3}^2\;(R^2=0.9714)$ and that of waxy corn starch dough was: $Y=32.617+12.535\;X_1+20.470\;X_2+8.608\;X_3+4.093\;{X_1}^2+13.550\;X_1X_2-4.467\;{X_2}^2+1.560\;X_1X_3+2.160\;X_2X_3-9.527\;{X_3}^2$\;(R^2=0.9621)$. As the moisture content, heating temperature and heating time increased, the reaction rate constant(k) of gelatinization increased. The greatest reaction rate constant was observed at initial 0.5 min heating time of 1st gelatinization stage. At the heating temperature of $90^{\circ}C$, gelatinization of starch dough was completed almost in the initial 0.5 min heating time. The reaction rate constant of waxy corn starch dough was higher than that of corn starch dough under the same gelatinization conditions. At the 52% moisture content, the regression equation between reaction rate constant(k) and heating temperature(T) for corn starch dough was $log\;k=11.1140-4.1226{\times}10^3(1/T)$ (r=-0.9520) and that of waxy corn starch dough was $log\;k=10.1195-3.7090{\times}10^3(1/T)$ (r=-0.9064).

• The Korean Journal of Food And Nutrition
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• v.11 no.1
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• pp.87-98
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• 1998

This study was conducted to investigate Osteoporosis on the effect of dietary factors and past young age period's dairy products consumption on BMD in 170 postmenopausal Korean women without diagnosed disease. Bone mineral density(BMD) of lumbar spine was investigated by dual energy X-ray absorptiometry. Dietary assesment of the subjects were measured by Cognitive Food Frequency Recall method. The measurements of group average were 57.9kg of body weight, 36.73 of BMI(Body Mass Index), 2103.3㎉ of energy, 638.7mg of dietary calcium, 70.3g of protein, and 10.58mg of iron. Nutrient intake levels were similar to or more than the level of Korean Recommended Dietary Allowances. Bone Mineral Density(BMD) of Lumbar spine(L2-L4) of group average was 0.912g/$\textrm{cm}^2$, and under 50 yr's 1,02g/$\textrm{cm}^2$, 50~54 yr's 0.92g/$\textrm{cm}^2$, 55~59 yr's 0.85g/$\textrm{cm}^2$, over 60 yr's 0.85g/$\textrm{cm}^2$, had been getting low degree on aging. BMD of the Lumbar spine was positively correlated with calorie, body weight, dietary calcium, protein, phosphorus and serum albumin. Past dairy products consumption experiment was highly significant on BMD in teenage period(R square = 26, p-value 0.0031). Particularly in over 60 yr group, the correlations between BMD and past dairy products consumption in teenage period had shown highly significance(r=0.48, p<0.02). 55~59 yr age group had also positive correlation(R squae = 0.29, p<0.05). This results confirm that the most effective way of preventing osteoporosis and the fractures is to maximize peak bone mass in early life and to minimize bone loss through the balanced intake of Ca and other nutrients and regular physical activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.1
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• pp.30-39
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• 2020

A new silicate coating technology was developed which reduces the impact of dust and loosening during seeding compared to existing silicate-coatings (Seed/Si/Zeolite), and therefore can lower the production costs of rice cultivation. In this method, 100 g of rice seed is coated with 18 mL of liquid silicic acid and then dressed with a mixture containing 80 g of dolomite and 5 g of iron. To determine the most effective method of application and ensure that seedlings developed healthily, a series of experiments were carried out. Infected seeds scattered in seedling boxes and pots (soil and hydroponic) were coated dry, without disinfection. In comparison to the seed which were not treated with the silicate-coating, the new seed (A) were 1.84 times heavier in weight, and were also improved in terms of coating strength and coating color. Compared to the seedlings grown from the non-coated seed, those grown from the new silicate-coated seed were of significantly higher quality (weight/length) and had erect, dark greenish leaves, which are ideal plant characteristics. This was most likely due to increased silicate uptake. The symptoms of bakanae disease in the non-coated seed peaked after 38 days to 54.2%, whereas the control value was 68.8% in the new silicate-coated seed (A). In the infected seedlings grown from the new silicate-coated rice seed, subnormal macro-conidia, namely, a sickle shape spore without a septum; a straight oblong shape spore without a septum and with a thick cell wall; and inter-septal necrosis of a normal spore were detected. It is believed that the strong alkalinity of silicic acid have acted as unfavorable conditions for pathogenicity. In seedlings grown from the new silicate coated rice seed under hydroponic conditions without nutrients, normal root activity and growth was maintained without leaf senescence. Therefore, it was possible to reduce the rate of fertilization. In the future, a new silicate-coated rice seed was required for the study of minimal nutrition for anti-aging of seedlings.