• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.43-50
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• 2000

Objectives: Obstructive sleep apnea syndrome(OSAS) is known to be associated with the changes of autonomic nervous system (ANS). Nasal continuous positive airway pressure(nCPAP) treatment was found to correct abnormal ANS changes in OSAS but it remains to be further clarified. We aimed to assess the effects of nCPAP on ANS manifested on electrocardiogram, using spectrum analysis in the subjects with OSAS. Methods: Digital polysomnography was performed in 18 patients with OSAS(mean age $43.7{\pm}16.6$ years ; 17 males, 1 female ; mean respiratory disturbance index (RDI) $48.6{\pm}20.9$) for one baseline and another CPAP nights. From each night, 300 continuous beats of ECGs without artifact were chosen from both stage 2 sleep and REM sleep and they were used for power spectrum analysis. We compared between baseline and CPAP nights the heart rate variability including VLF(very low frequency power), LF (low frequency power), HF(high frequency power), R-R means, R-R variance, and LF/HF ratio, using Wilcoxon signed ranks test. Results: In all patients, nCPAP proved to be effective in relieving apneas and snoring. During nCPAP night compared with baseline night, decreases in VLF(p<0.05), LF(p<0.01), and R-R variance(p<0.05) were found in stage 2 sleep, and decreased LF(p<0.05) was found in REM sleep. No significant differences in each sleep stage were found in other variables between the two nights. Conclusion: Our findings suggest that OSAS increases the activity of sympathetic nervous system and nCPAP application effectively decreases the activity. And nCPAP does not appear to influence the parasympathetic nervous activity in OSAS.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.4
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• pp.260-266
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• 2008

Small lysimeter experiment under rain shelter plastic film house was conducted to investigate the effect of soil characteristics on the leaching and soil solution concentration of nitrate and phosphate. Three soils were obtained from different agricultural sites of Korea: Soil A (mesic family of Typic Dystrudepts), Soil B (mixed, mesic family of Typic Udifluvents), and Soil C (artificially disturbed soils under greenhouse). Organic-C contents were in the order of Soil C ($32.4g\;kg^{-1}$) > Soil B ($15.0g\;kg^{-1}$) > Soil A ($8.1g\;kg^{-1}$). Inorganic-N concentration also differed significantly among soils, decreasing in the order of Soil B > Soil C > Soil A. Degree of P saturation (DPS) of Soil C was 178%, about three and fifteen times of Soil B (38%) and Soil A (6%). Prior to treatment, soils in lysimeters (dia. 300 mm, soil length 450 mm) were tabilized by repeated drying and wetting procedures for two weeks. After urea at $150kg\;N\;ha^{-1}$ and $KH_2PO_4$ at $100kg\;P_2O_5\;ha^{-1}$ were applied on the surface of each soil, total volume of irrigation was 213 mm at seven occasions for 65 days. At 13, 25, 35, 37, and 65 days after treatment, soil solution was sampled using rhizosampler at 10, 20, and 30 cm depth and leachate was sampled by free drain out of lysimeter. The volume of leachate was the highest in Soil C, and followed by the order of Soils A and B, whereas the amount of leached nitrate had a reverse trend, i.e. Soil B > Soil A > Soil C. Soil A and B had a significant increase of the nitrate concentration of soil solution at depth of 10 cm after urea-N treatment, but Soil C did not. High nitrate mobility of Soil B, compared to other soils, is presumably due to relatively high clay content, which could induce high extraction of nitrate of soil matrix by anion exclusion effect and slow rate of water flow. Contrary to Soil B, high organic matter content of Soil C could be responsible for its low mobility of nitrate, inducing preferential flow by water-repellency and rapid immobilization of nitrate by a microbial community. Leached phosphate was detected in Soil C only, and continuously increased with increasing amount of leachate. The phosphate concentration of soil solution in Soil B was much lower than in Soil C, and Soil A was below detection limit ($0.01mg\;L^{-1}$), overall similar to the order of degree of P saturation of soils. Phosphate mobility, therefore, could be largely influenced by degree of P saturation of soils but connect with apparent leaching loss only more than any threshold of P accumulation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.6
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• pp.933-940
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• 2013

In this study, methyl esters with different saturated fatty acids (SFA) were prepared by urea fractionation to make an oil-in-water emulsion. Emulsion characteristics (emulsion stability and oxidative stability) of the methyl ester emulsion were then studied at different percentages of methyl ester saturation (5, 28, 39, 50, and 72%, termed ${\Sigma}$SFA5, ${\Sigma}$SFA28, ${\Sigma}$SFA39, ${\Sigma}$SFA50, and ${\Sigma}$SFA72, respectively). The stability of emulsions (ES) with different SFA content was 46.0 (${\Sigma}$SFA5), 39.5 (${\Sigma}$SFA28), 32.7 (${\Sigma}$SFA39), 32.6 (${\Sigma}$SFA50), and 27.3 (${\Sigma}$SFA72). Results from Turbiscan showed that creaming or clarification, based on the backscattering intensity, was more pronounced with increases in the saturation degree of the emulsion. These results implied that the emulsions with lower saturation were more stable. During 30 days of storage, the lipid peroxide value increased for all emulsions, with the increase less pronounced with the increasing saturation of the emulsion; 1.880 (${\Sigma}$ SFA5), 1.267 (${\Sigma}$SFA28), 1.062 (${\Sigma}$SFA39), 0.342 (${\Sigma}$SFA50) and 0.153 (${\Sigma}$SFA72) mg $H_2O_2/mL$ emulsion. In addition, thiobarbituric acid reactive substances (TBARS) values were significantly lower in emulsions with high saturation (4.419 mg for ${\Sigma}$SFA50 and 4.226 mg for ${\Sigma}$SFA72) than emulsions with low saturation (6.229 mg for ${\Sigma}$SFA5, 6.801 mg for ${\Sigma}$SFA28 and 6.246 mg for ${\Sigma}$SFA39). In conclusion, the emulsions with a higher saturation degree of methyl esters showed lower emulsion stability but better oxidation stability.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.151-157
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• 2017

The objectives of this study were to determine the impact of soil water content on the growth, stomatal conductance, and photosynthesis of Kimchi cabbage and to evaluate proper parameters for development of growth models. There were five levels of irrigation amount treatments (0, 200, 300, 400, and 500 mL/d/plant) and those were commenced at one day after transplanting (DAT). We measured soil water content, stomatal conductance, photosynthesis characteristics, and the A-Ci curve. The growth of Kimchi cabbage as affected by irrigation amount was evaluated at 38 days after transplanting, however, the growth with 0 and 200 mL/d/plant irrigation amount treatments measured at 29 DAT. The relationship between soil water content and stomatal conductance was highly correlated ($r^2=0.999$) and the function represented by y = 6097.4x - 4.2984. The stomatal conductance of Kimchi cabbage leaves showed $300mmol{\cdot}m^{-2}{\cdot}s^{-1}$ when the soil water content was below $0.05m^3/m^3$. The stomatal conductance was rapidly decreased by scarcity of soil moisture. A-Ci curve indicated normal curve in fully irrigation treatment (500 mL/d/plant), however, $CO_2$ couldn't diffuse through the intercellular Kimchi cabbage leaves treated with 0 mL/d/plant. The dry weight of full irrigation treatment was greater approximately 6.8 times than that of deficit irrigation (0 mL/d/plant). In addition, leaf area index showed a logarithmic function (y = 16.573 + 3.398 ln x) with soil water content and that of R-squared represents 0.913. Results indicated that the soil water content was highly correlated with stomatal conductance and leaf area index. Indeed, the scarcity soil moisture reduced photosynthesis and retarded growth.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.273-279
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• 2000

The influence of different storage temperature and packaging methods on plain dried anchovy were investigated. When plain dried large anchovy (DLA) was stored at $-20^{\circ}C, 5^{\circ}C and 2^{\circ}C$, the lipid oxidation was rapidly progressed with the increased temperature. When DLA was stored at $25^{\circ}C and 5^{\circ}C$, peroxide value (POV) reached to maximum on 4 days and 20 days, respectively, while POV increased progressively during storage at $-25^{\circ}C$. The degree of lipid oxidation was progressed the fastest in DLA packed in polyethylene film, followed by packing with oxygen absorber and packing in vacuum. The fatty acid composition of total lipid in DLA revealed $52.3{\%}$ in polyenes, $29.2{\%}$ in saturates and 1$8.5{\%}$ in monoenes, and the major fatty acids were 22 : 6, 20 : 5, 16 : 0, 16 : 1 and 18: 1. Saturates were increased with the rise of storage temperature and prolonging the storage period, while polyenes were decreased. The changes of fatty acid composition was retarded at lower temperature. And the changes of fatty acid composition were the lowest in DLA by vacuum packing, followed by packing with oxygen absorber and packed in polyethylene film. The contents of highly unsaturated fatty acid of polyenes were decreased remarkably in proportion to the progress of lipid oxidation, while saturates were increased.

• Clinical and Experimental Pediatrics
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• v.45 no.4
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• pp.498-504
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• 2002

Purpose : The purpose of this study was to evaluate the perioperative myocardial damage in pediatric congenital heart disease with the cardiac specific protein of cardiac troponin I(cTpn-I). Methods : All 25 pediatric patients who were diagnosed with tetralogy of Fallot or double outlet right ventricle were classified as group A(acyanotic, $SaO_2$ >90%), group B(mildly cyanotic, $SaO_2$ >80-90%) and group C(moderately cyanotic, $SaO_2$ <80%). The control group D was consisted of 10 patients with ventricular septal defects who were operated in the same period. We measured preoperative hemoglobin, preoperative and postoperative(24 and 72 hour) arterial oxygen saturation, cTpn-I and creatine kinase(CK-MB). Results : Total 25 patients were subdivided into 6 of group A, 12 of group B and 7 of group C. The concentrations of preoperative cTpn-I were $0.23{\pm}0.12ng/mL$ in group A, $0.25{\pm}00.12 ng/mL$ in group B, $0.26{\pm}0.13ng/mL$ in group C. And the concentrations of cTpn-I in postoperative 24 hour were $10.04{\pm}5.28ng/mL$ in group A, $12.50{\pm}6.86ng/mL$ in group B, $12.55{\pm}9.90ng/mL$ in group C. Which revealed cTpn-I in group C was higher than that of the another less cyanotic groups. In addition, the concentration of cTpn-I of group C in postoperative 72 hour was higher than any other groups. The concentration of cTpn-I in postoperative 72 hour was statistically correlated with that in postoperative 24 hour and preoperative arterial oxygen saturation(P=0.001). Conclusion : Preoperative chronic cyanosis can influence on the postoperative concentration of cTpn-I in pediatric cardiac patients, which means impairment on the postoperative myocardial recovery.

• Clinical and Experimental Pediatrics
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• v.46 no.4
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• pp.376-381
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• 2003

Purpose : This study aimed to demonstrate the possible pathogenesis of granulopoiesis in patients of Kawasaki disease(KD) using quantitative analysis of G-CSF, GM-CSF and their CSFr. Methods : The plasma levels of G-CSF, GM-CSF, G-CSFr and GM-CSFr were studied in 14 patients in the acute phase of KD; 13 children with normal peripheral white blood cell counts were used as the normal control group. The plasma concentration of G-CSF, GM-CSF were analyzed by ELISA. The G-CSFr and GM-CSFr on the peripheral granulocytes were analyzed by a quantitative flow cytometric assay and QuantiBRITE, and the quantitative changes of receptors which did not combine with G-CSF and GM-CSF were measured. Results : The total number of leukocytes in KD was similar to normal control group, but the leukocytes increased according to the number of neutrophils. The plasma concentration of G-CSF were decreased similar to normal control group(P=0.133), but that of GM-CSF decreased more than the normal control group(P=0.227). The quantity of G-CSFr, GM-CSFr were revealed to be no less than the normal control(P=0.721, P=0.912). After incubation with excessive G-CSF, the expressed G-CSFr on the neutrophils were decreased in both groups(P=0.554). The quantities of expressions of GM-CSFr on the neutrophil after incubation with the excessive GM-CSF were always increased in both groups(P=0.255). The amount of GM-CSFr of neutrophils are in proportion to total white blood cells (r=0.788, P=0.035), but it wasn't in the case of KD(P=0.644). Conclusion : The leukocytosis in KD that mediated by increasing neutrophil was not correlated with the plasma concentrations of G-CSF and GM-CSF, and the amount of expression of G-CSFr and GM-CSFr on granulocyte. It is possible that the reduction of concentration of GM-CSF results by increasing the active GM-CSFr.

• Journal of the Korean Vacuum Society
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• v.18 no.2
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• pp.147-150
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• 2009

We present a technique for fabricating low leakage organic field-effect transistors by a functional polydimethylsiloxane (PDMS) layer. The technique relies on the photo-chemical process of conversion of the PDMS to a silicon oxide which provides the selective growth of pentacene thin films. The reduced gate leakage current showed ${\sim}10^{-10}$ A in a linear ($V_d=-5\;V$) and saturation ($V_d=-30\;V$) region at $V_g-V_t>0$.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.3
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• pp.139-141
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• 2013

In respect of environmental hazard or human safety, the use of the chloride-based packaging materials like polyvinyl chloride (PVC) blister and film, Polyvinylidene chloride (PVDC) laminated film has been restricted with national regulations. In this study, I intended to develope the reagent solution for identifying the chloride-based packaging materials, so that it was made by mixing methanol ($CH_3OH$) saturated with sodium hydroxide (NaOH) and pyridine as solvent with same ratio. The efficacy of this reagent solution was verified by the analysis of chemical mechanism and experiments that showed the color change (brown) of the specimens. This analysis methode using reagent solution is so simple, convenient, inexpensive and immediate that I expect it will be useful in the field of packaging.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.04a
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• pp.163-163
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• 2013

최근의 수많은 산업 현장에서 취급하고 있는 각종 화학물질은 잠재적 위험성이 크므로 보관, 수송 및 취급할 때 특별한 주의가 필요하다. 공정 설계 시 정확하지 않은 폭발한계를 사용함으로서 사고가 유발되는 경우가 많다. 따라서 사업장에서 사용되고 있는 화학물질의 화재 및 폭발 특성치인 인화점, 폭발한계 등을 정확히 파악하는 것은 중요하다. 인화점은 하부인화점과 상부인화점으로 나누고 있고 있으며, 인화점은 가연성 액체의 화재 위험성을 나타내는 지표로써, 가연성액체의 액면 가까이서 인화할 때 필요한 증기를 발산하는 액체의 최저온도 또는 점화원 존재시 인화가 일어날 수 있는 최저온도, 그리고 가연성증기의 포화증기압이 공기와 혼합기체의 폭발한계 하한농도와 같게 되는 온도로 정의한다. 폭발한계는 발화원이 존재할 때 가연성가스와 공기가 혼합하여 일정 농도범위 내에서만 연소가 이루어지는 혼합범위를 말한다. 본 연구에서는 실제 공정에서 사용되고 있는 n-Hexadecane의 인화점을 측정하여 이를 기존 문헌값과 비교 하였고, 측정된 인화점을 이용하여 폭발한계를 예측하였다. 예측된 폭발한계를 여러 문헌에 제시된 자료과 비교하여 공정안전에 타당한 자료를 제시하였다. 본 연구는 n-Hexadecane을 취급하는 공정에서 안전 확보의 중요한 지침 마련과 MSDS D/B의 최신화에 유용한 정보를 제공하는데 목적이 있다.