• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.144-152
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• 2019

Learning styles are the methods of gathering, processing, interpreting, organizing the information. VARK learnig inventory is instructional preference classified according to their visual(V), aural(A), read-write(R), and/or kinesthetic(K) sensory modality preferences(SMP). Learner-centered learning is emphasized, but there are few studies on VARK learning styles in Korean medical school. The purposes of this study were to assess the student' SMPs and compare those with gender, status, and academic achievement. The subjects of study were 394 students at C Medical School and Graduate School of Medicine. For the study style test, 16 questions were used in Korean version of VARK test paper© 7.0 developed by Fleming provided on the VARK website. Academic achievement was converted into a standardized score(t score). Frequency analysis, cross analysis, and variance analysis(t-test, ANOVA) were conducted to identify learning style disposition and differences between groups. The uni-modal type was 87(22.1%) and the multimodal was 307(77.9%). Regardless of gender, quasi-modal VARK was the most preferred. There was no significant difference in learning styles by gender. The first grade in medicine was the lowest in uni-modal type(8.8%) and the highest in quasi-modal VARK type(47.8%), while the fourth grade was the highest in uni-modal type(30.7%) and the lowest in quasi-modal VARK type(19.8%) and tri-modal type(19.8%). There was no difference in academic achievement by all learning types(F=1.09, p=0.37). The knowledge about students' learning styles is helpful for instructors to apply more learner-centered teaching strategies in medical education.

• Journal of Embryo Transfer
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• v.13 no.1
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• pp.11-19
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• 1998

This study was to determine the effect of ionomycin and 6-dimethylaminopurine (6-DMAP) and/or elcetrical stimulation on the oocyte activation and production of rabbit nuclear transplant embryos. The oocytes were collected from the oviduct of superovulated rabbits at 14 h post hCG injection and cultured in TCM-199 containing 10% FBS until 19 h post hCG injection. To determine the optimum concentration and exposure time of 6-DMAP, some oocytes were activated with 5 $\mu$M ionomycin for 5 min and then in 2.0 mM 6-DMAP for 0.5 to 3.0 h, or in 1.0 to 3.0 mM 6-DMAP for 2.0 h. Other control oocytes were stimulated electrically(3X, 1.25 kV/cm, 60 $\mu$sec) in 0.3 M mannitol solution supplemented with 100 $\mu$M CaCl$_2$ and MgCl$_2$. The nuclear donor embryos of 8-cell stage were synchronized to G$_1$ phase of 16-cell stage, and the recipient cytoplasms were obtained from removal of the first polar body and a portion of membrane bound cytoplasm of the oocytes collected at 15 h post hCG injection. A separated blastomere was injected into the perivitelline space of the enucleated oocytes. The oocytes injected with nucleus were cultured until 19 h post hCG and then electrofused and activated by electrical stimulation with or without ionomycin and 6-DMAP. These nuclear transplant embryos were cultured in TCM-199 containing 10% FBS in 39˚C, 5% CO2 incubator for 120 h. For the oncytes activated parthenogenetically with electrical stimulation with or with-out ionomycin and the various concentration of exposure time of 6-DMAP, the highest cleavage(92.3%) and development to blastocyst stage(41.0%) were resulted from the oocytes activated by ionomycin and 2.0 mM 6-DMAP for 2.0 h, which were found to be significantly(P<0.05) higher than the cleavage(45.2%) and developement to blastocyst stage(14.3%) from the oocytes activated with electrical stimulation. The significantly(P<0.05) more oocytes(71.4%) developed to 4 cell stage at 24 h post activation by ionomycin and 6-DMAP than those by electrical stimulation(18.9%). For the nuclear transplant embryos, the cleavage rate was similarly high in oocyte activation by electrical stimulation with(79.4%) or without ionomycin and 6-DMAP(70.5%). However, the embryo development to blastocyst stage was significantly(P<0.05) higher in oocyte activation by electrical stimulation with ionomycin and 6-DMAP(44.4%) than by electrical stimulation only(25.0%). The significantly(P<0.05) more nuclear transplant embryos(45.6%) developed to 4 cell stage at 18 h post activation by electrical stimulation with ionomycin and 6-DMAP than those by electrical stimulation only(10.6%). These results indicated that the supplemental oocyte activation by ionomycin and 6-DMAP with electrical stimulation enhanced and accelerated the preimplanted in vitro development of the rabbit nuclear transplant embryos.

• Journal of the Korean Ceramic Society
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• v.40 no.10
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• pp.943-948
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• 2003

The microstructure and electrical characteristics of Zn-Pr-Co-Cr-Dy oxides-based varistors were investigated with Dy$_2$ $O_3$ content in the range of 0.0∼2.0 ㏖%. As Dy$_2$ $O_3$ content is increased, the average grain size was decreased in the range of 18.2∼4.6 $\mu\textrm{m}$ and the ceramic density was decreased in the range of 5.49∼4.64 g/㎤. The incorporation of Dy$_2$ $O_3$ markedly enhanced the nonlinear properties of varistors more than 9 times in nonlinear exponent, compared with the varistor without Dy$_2$ $O_3$ The varistor with 0.5∼1.0 ㏖% Dy$_2$ $O_3$ exhibited the high nonlinearity, in which the nonlinear exponent is above 55 and the leakage current is below 1.0 ${\mu}\textrm{A}$. The donor concentration and the density of interface states were decreased in the range of (4.66∼0.25)${\times}$10$\^$18//㎤ and (5.70∼1.39)${\times}$10$\^$12//$\textrm{cm}^2$, respectively, with increasing Dy$_2$ $O_3$ content. The minimum dielectric dissipation factor of 0.0023 was obtained for 0.5 ㏖% Dy$_2$ $O_3$, but further addition of Dy$_2$ $O_3$ increased it.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.389-400
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• 2011

A high-performance liquid chromatographic (HPLC) method was developed to determine residues of phenothrin and silafluofen, known as synthetic pyrethroids, in agricultural commodities. Insecticide residues were extracted with acetone from representative samples of four crops which comprised rice, apple, pepper and cabbage. The extract was purified serially by liquid-liquid partition and Florisil column chromatography. For rice and pepper samples, acetonitrile/n-hexane partition was additionally adopted to remove nonpolar interferences. Reversed phase HPLC using an octadecylsilyl column was successfully applied to separate two phenothrin isomers and silafluofen from sample co-extractives. Intact parent compounds were sensitively detected by ultraviolet absorption at 226 nm. Recovery experiment at the quantitation limit validated that the proposed method could apparently determine phenothrin and silafluofen residues at 0.02 and 0.01 mg/kg, respectively. Mean recoveries of phenothrin and silafluofen from four crop samples fortified at three levels in triplicate were in the range of 82.4~109.8% and 83.7~109.8%, respectively. Relative standard deviations of the analytical method were all less than 10%, irrespective of crop types and spiking levels. A selected-ion monitoring (SIM) LC/mass spectrometry (MS) with electrospray ionization was provided to confirm the suspected residue of phenothrin, even though no sufficient ionization of silafluofen was obtained. Both phenothrin and silafluofen could be successfully confirmed by gas chromatography/MS SIM with electron impact at 70 eV. The proposed method is sensitive, repeatable and rapid enough to apply to officially routine inspection of agricultural products.

• Journal of Surface Science and Engineering
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• v.40 no.6
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• pp.254-257
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• 2007

TiN coating on tool steel has been widely used for the improvement of durability of tools. In this work, radical nitriding(RN) is carried out on SKD61 at $450^{\circ}C$ for 5 hours in the ammonia gas pressure $2.7{\times}10^3\;Pa$. The TiN coating is carried out by arc ion plating(AIP) with the process parameters: arc power 150 A, bias voltage -50V, coating time 40 minutes and nitrogen gas pressure $4{\times}10^3\;Pa$. Hardness, elastic modulus, friction coefficient and adhesion of TiN coating on substrates of both TiN/SKD61 and TiN/RN SKD61 coatings are investigated comparatively. The primary crystalline faces of TiN surface are(200) and(111) for TiN/SKD61 and TiN/RN SKD61 respectively. In addition to the primary phase, Fe phase exists in TiN/SKD61 coating, but not in TIN/RN SKD61. The hardness of TiN/RN SKD61 is about 700 Hv, 250 Hv(56%) higher than that of TiN/SKD61 at the near interface of TiN and substrates. At the TiN surface, hardness of TiN/RN SKD61 is 2,149 Hv, 71 Hv(3%) higher than that of TiN/SKD61. The elastic modulus of TiN coating is improved to 26.7 GPa(6%) by radical nitriding. The adhesion is improved by the RN coating showing no spalling. buckling and chipping on the scratch test track which are shown on the non-RN TiN/SKD61.

• Korean Journal of Acupuncture
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• v.17 no.1
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• pp.81-100
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• 2000

Transsynaptic tracer이며 신경친화성 virus인 pseudorabies virus(PRV)를 방광(膀胱), 방광유(膀胱兪), 위중(委中) 및 중추(中極)에 주입(注入)한 후 4일간의 생존기간이 경과한 후 희생시켜 면역조직화학침액법(免疫組織化學染色法)에 의하여 뇌척수에 표지된 공통된 영역들을 비교하여 관찰한 결과는 다음과 같다. 1. 방광벽(膀胱壁), 방광유(膀胱兪), 위중(委中) 및 중추(中極)에서 척수에 투사된 영역은 흉수(胸髓), 요수(腰髓) 및 천수(薦髓)에 모두 표지되었으며 공통적으로 표지된 부위는 척수(脊髓)의 층판 IV, V, VII, IX, X영역에 표지되었으나 주로 강하게 표지된 공통된 영역은 층판 VII의 중간외측핵, 가슴기둥 및 층판 X영역이었다. 2. 방광벽(膀胱壁), 방광유(膀胱兪), 위중(委中) 및 중추(中極)에서 뇌(腦)에 투사된 공통된 영역은 연수(延髓)에서는 A1 noradrenalin cells/C1 adrenalin cells/caudoventrolateral reticular nucleus에서 양성반응을 나타내었다. 솔기핵의 경우 아핵인 불명솔기핵, 창백솔기핵 및 큰솔기핵에서 양성반응을 보였다. 다리뇌에서는 청색반점, Barrington's nucleus, A5세포군 및 삼차신경운동핵에서 양성반응을 보였고, 중뇌에서는 눈돌림신경핵, 눈돌림신경섬유 및 다리핵에서 양성반응을 보였다. 간뇌에서는 시상하부(視床下部)의 뇌실(腦室)곁핵과 시상의 뇌실곁핵에서 양성반응을 보였고 대뇌(大腦)에서는 septal nucleus, 피질(皮質)의 뒷다리영역, 마루엽, 이마엽에서 양성반응을 보였다. 이상의 결과를 종합하면 방광(膀胱)에서 투사되는 뇌척수의 영역과 방광유(膀胱兪)나 위중(委中)에서 투사되는 공통된 표지영역들은 방광(膀胱)과 족태양방광경(足太陽膀胱經) 그리고 그 경락(經絡)의 경혈(經穴)들이 어떤 상관성(相關性)을 가지고 연결(連結)되어 있다는 사실을 실험적으로 알 수 있었다. 특히 방광(膀胱)과 방광유(膀胱兪), 위중(委中)에서 투사된 공통된 표지영역, 즉 배뇨중추인 Barrington's nucleus에 표지되는 것은 내장(內臟)-경락(經絡)이 central autonomic pathway에 의하여 서로 연결되었음을 입증하는 중요한 결과(結果)라고 사려(思慮)된다.

• Journal of Pharmaceutical Investigation
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• v.38 no.2
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• pp.127-134
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• 2008

Peroral administration is the most convenient one for the administration of pharmaceutically active compounds. Most of poorly water-soluble drugs administered via the oral route, however, remain poorly available due to their precipitation in the gastrointestinal (GI) tract and low permeability through intestinal mucosa. In this study, one of drug delivery carriers, lipid nanoparticles (LNPs) were designed in order to reduce side effects and improve solubility and stability in GI tract of the poorly water soluble drugs. However, plain LNPs are generally unstable in the GI tract and susceptible to the action of acids, bile salts and enzymes. Accordingly, the surface of LNPs was modified with polyethylene glycol (PEG) for the purpose of improving solubility and GI stability of paclitaxel (PTX) in vitro. PEG-modified LNPs containing PTX was prepared by spontaneous emulsification and solvent evaporation (SESE) method and characterized for mean particle diameter, entrapping efficiency, zeta potential value and in vitro GI stability. Mean particle diameter and zeta potential value of PEG-modified LNP containing PTX showed approximately 86.9 nm and -22.9 mV, respectively. PTX entrapping efficiency was about 70.5% determined by UV/VIS spectrophotometer. Futhermore, change of particle diameter of PTX-loaded PEG-LNPs in simulated GI fluids and bile fluid was evaluated as a criteria of GI stability. Particle diameter of PTX-loaded PEG-LNPs were preserved under 200 nm for 6 hrs in simulated GI fluids and bile fluid at $37^{\circ}C$ when DSPE-mPEG2000 was added to formulation of LNPs above 4 mole ratio. As a result, PEG-modified LNPs improved stability of plain LNPs that would aggregate in simulated GI fluids and bile solution. These results indicate that LNPs modified with biocompatible and nontoxic polymer such as PEG might be useful for enhancement of GI stability of poorly water-soluble drugs and they might affect PTX absorption affirmatively in gastrointestinal mucosa.

• Korean Journal of Community Nutrition
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• v.13 no.3
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• pp.418-425
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• 2008

The purpose of this study was to investigate correlations between bone mineral density (BMD) and dietary and non-dietary factors in female college students. The BMD of the subjects (n = 38) was measured using DEXA (Dual Energy X-ray Absorptiometry) at lumbar spine and three femoral sites including femoral neck, ward's triangle, and femoral trochanter. Three-day 24-hour dietary recall data were collected from each subject to assess consumption levels of nutrients and food groups. The mean (${\pm}SD$) values of age, age of menarche, height, weight, body mass index (BMI), waist-to-hip ratio (WHR), fat mass, and % body fat of the subjects were 21.34 (${\pm}1.73$) years, 13.1 (${\pm}1.2$) years, 161.3 (${\pm}5.0$) cm, 53.7 (${\pm}7.2$) kg, 20.6 (${\pm}2.6$) $kg/m^2$, 0.80 (${\pm}0.04$), 15.4 (${\pm}4.4$) kg, and 28.2 (${\pm}4.7$), respectively. The BMD values of lumbar spine, femoral neck, ward's triangle, and femoral trochanter as T-value were $1.150{\pm}0.13\;g/cm^2$, $0.932{\pm}0.11\;g/cm^2$, $0.850{\pm}0.13\;g/cm^2$, and $0.721{\pm}0.10\;g/cm^2$, respectively. The daily mean energy intake of the subjects was 1660.6 kcal. The intake levels of carbohydrate, calcium, iron, vitamin C, and folic acid were lower than the KDRIs, while those of fat, phosphorus, sodium, vitamin A, and vitamin $B_6$ were higher than the KDRIs. Significantly negative correlation were detected between consumption of fat and oils and the BMD of all sites measured (p < 0.05). Potato and starch intake was negatively correlated to the BMD of femoral neck and word's triangle (p < 0.05). The intake of cereals was found to be negatively correlated to the BMD of ward's triangle (p v 0.05). There was also negative correlation of intake of soybeans and products with the BMD of lumbar spine (p < 0.05). Weight and muscle mass were positively correlated to the BMD of both lumbar spine and femurs (p < 0.01). Significantly positive correlations between BMI, and fat mass and the BMD of lumbar spine were observed (p < 0.001). Additionally fat mass was positively correlated to the BMD of femoral neck. WHR and % body fat were positively correlated to the BMD of lumbar spine (p < 0.05). Negative correlation was found between a serum calcium level and the BMD of femoral neck (p < 0.05). In summary non-dietary factors generally showed significant correlations with the BMD of lumbar spine, while several dietary factors showed significant correlations with the BMD of femurs.

• Korea journal of population studies
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• v.8 no.1
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• pp.118-138
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• 1985

This paper is aimed to analyse the recent changes in family planning as a step in an evaluation of the results of the population control policy which has been strenuously pursued by the government since December 1981. The data used in this analysis comes from the 1985 national fertility and family planning survey conducted by the Korea Institute for Population and Health (KIPH) in May 1985. According to the 1985 survey data, there have been great changes in both the contraceptive practice and fertility rates since the strengthening of the government's population control policy in 1 981. The contraceptive practice rate for married women aged 15-44 has increased from 57.7% in 1982 to 70.3% in 1985, an increase of 12.6% points in the short span of only 3 years. During the same period, the total fertility rate has declined from 2.7 in 1982 to the population replacement level which was planned to achieve by 1 988. More than 80% of women aged over 30 or with two children or more are practicing contraception, while the practice rates of women with 0-1 children are 14.0% and 45.1% respectively. The survey has revealed that the increase of contraceptive practice rate during 1982-1985 has mainly attributed to the high acceptance of sterilization procedures which practice rate of the married women has increased from 28.1% to 40.3% for the period. Also, the survey data shows that 24.7% of those women with only one child is practicing contraception for thepurpose of fertility termination. The government, taking into account of rapid changes in contraceptive practice and fertility rates, is formulating a population plan during the sixth fiveyear economic and social development plan (1987-1991) to achieve 1% ofpopulation growth rate by 1993, which was planned to realize by 2000. In order to meet this demographic goal, the existing population control policy measures should be improved to be suited to the recent contraceptive use and fertility changes. From this standpoint, the following considerations should be put forth; 1) improvement of the current program management systems including target allocation and evaluation schems for recruiting new acceptors in the young 20s groups to use contraceptives for birth spacing and to increase high continuation rates through the strengthening of follow-up services for the acceptors, 2) increase of self-supporting contraceptive users by promoting commercial advertisements on contraceptives through mass media including T.V. and radio, 3) development of social support policies including incentive schems, and strengthening of IE & C activities for increasing the proportion of the one-child family, 4) strengthening of population and family planning education in and out school youth, and 5) strengthening of management capabilities at the provincial and local program managers.

• Korean journal of food and cookery science
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• v.17 no.2
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• pp.156-164
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• 2001

Four different oligosaccharides used to determine their effects on gelatinization and retrogradation of Backsulgies(BSG), Korean traditional rice cake, were cyclodextrin, isomaltooligosaccharide, fructooligosaccharide and maltotetrose, with 3 or 6%(w/w), based on the rice flour. From the Amylograph and blue value data, adding 6% cyclodextrin into the rice flour fastened the gelatinzation process, and delayed the retrogradation in stored BSG at 4$\^{C}$ for up to 3 days, probably due to its cyclic structure. Using rheometer, the hardness of freshly made BSG added with cyclodextrin was significantly lower than that of control BSG, and increased with storage time in all BSGs at refrigerated temperature. When using maltotetrose in rice flour, the hardness of BSG was also significantly low, but slightly higher than that of cyclodextrin. Hunter “L” value in BSG decreased with the addition of oligosaccharides, but the higher the level of oligosaccharide in BSG, the insignificant the Hunter “a”,“b” values of BSG. From the X-ray diffraction studies, the rice flour showed typical A pattern, and the crystallinities of all BSG gave amorphous V type. The highest peaks of X-ray patterns in BSG added with 6% cyclodextrin or maltotetrose were, however, lower than that of the control, meaning the less crystalline, retrograded starch in the former BSGs. Based on sensory evaluation, BSG added with all oligosacchrides were not significantly different in taste, flavor, chewiness, moistness and overall preferences, with slightly darker color with longer storage time, compared to the control BSG.