• Journal of Food Hygiene and Safety
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• v.25 no.2
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• pp.118-121
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• 2010

A HPLC-MS/MS method was developed for simultaneous determination of six sweeteners (acesulfame-K, cyclamate, saccharin, sucralose, stevioside, aspartame) in children's favorite foods. The procedure involves an extraction of the six sweeteners with 50% methanol solution, sample clean-up using the Carrez clearing reagent and filtering with cartridge filter. The HPLC separation was performed on a Hypersil Gold (150 mm ${\times}$ 2.1 mm 5 um) column using the water/acetonitrile mobile phase (95:5). Mass spectrometric analysis was carried out using the TSQ Quantum Ultra operated in negative and positive ESI/SRM. With this method, good linear relationship, sensitivity and reproducibility were obtained. The spike recoveries of six sweeteners for 2 kinds of foods spiked into 0.4 mg/ kg ranged from 87.4 to 114.7%. The detection limits were above 0.02 mg/kg. The method has been applied to determination of six sweeteners in children's favorite foods.

• YAKHAK HOEJI
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• v.55 no.2
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• pp.106-115
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• 2011

Systematic toxicological analysis (STA) means the process for general unknown screening of drugs and toxic compounds in biological fluids. In order to establish STA, in previous study we investigated pattern of drugs & poisons in autopsy cases during 2007~2009 in Korea, and finally selected 62 drugs as target drugs for STA. In this study, rapid and simple drug identification and quantitative analytical program by gas chromatography-mass spectrometry(GC-MS) was developed. The in-house program, "DrugMan", consisted of modified chemstation data analysis menu and newly developed macro modules. Total 55 drugs among 62 target drugs were applied to this program, they were 14 antidepressants, 8 anti-histamines, 5 sedatives/hypnotics, 5 narcotic analgesics, 3 antipsychotic drugs, and etc. For calibration curves, fifty five drugs were divided into four groups of range considering their therapeutic or toxic concentrations in blood specimen, i.e. 0.05~1 mg/l, 0.1~1 mg/l, 0.1~5 mg/l or 0.5~10 mg/l. Standards spiked bloods were extracted by solid-phase extraction (SPE) with trimipramine-D3 as internal standard. Parameters such as retention times, 3 mass fragment ions, and calibration curves for each drug were registered to DrugMan. A series of identification, semi quantitation of target drugs and reporting the results were performed automatically. Calibration curves for most drugs were linear with correlation coefficients exceeding 0.98. Sensitivity rate of DrugMan was 0.90 (90%) for 55 drugs at the level of 0.5 mg/l. For standard spiked bloods at the level of 0.5 mg/l for 29 drugs, semi quantitative concentrations were ranged 0.36~0.64 mg/l by DrugMan. If more drugs are registered to database in DrugMan in further study, it will be useful tools for STA in forensic toxicology.

• The Research Journal of the Costume Culture
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• v.18 no.2
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• pp.261-276
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• 2010

The analysis of an art trend in the principle dimension starts by observing the object of work in the perspective of formative composition and recognizing it as a universal system. It can be said that it is consistent with an interpretation method for a form theory of formal history by Heinrich W$\ddot{o}$lfflin, a leading form critic in art criticism. Hence, the purpose of this study was to find out what are the formative principles in Renaissance Classicism as a design principle to be applicable to modern fashion by reviewing the formative characteristics of Renaissance Classicism Architecture with which W$\ddot{o}$lfflin directly dealt. As for the theoretical literature review, I used W$\ddot{o}$lfflin's theoretical framework and looked at the Renaissance Classicism Architecture that he studied and examined the possibility of utilizing his theory as a layout principle and the characteristics. As for analysis of design cases, I applied the aforementioned architecture layout principle to modern fashion and conducted case study analysis to delve into distinctive layout principles found in fashion. The study showed that the Renaissance Classicism Architectural Style is marked by linearity, planarity, closing and multiple unity: linearity was expressed in the observation form in fixed frontal view and an emphasis on a tangible silhouette homeogenous and definite line structures; planarity was achieved in the form of paralleled layers of frontal view element, planarity style, and identical and proportional repetition of various sizes.; closing signified the pursuit of complete and clear regularity, and architecture developed in a constructive phase through organizational inevitability and absolute invariability.; multiple unity was expressed in self-completedness and independent parallel of discrete forms and harmony of emphasized individual elements in a totality. Applying these layout characteristics of the Renaissance Classicism Architectural style and to see their individual expressive features, I found out that in adopting layout principles of the Renaissance Classicism Architecture to modern fashion, it turned out to be an emphasis of individual silhouettes, a flattened space, completed objects, organic harmony among independent parts: the emphasis of individual silhouettes was expressed in individual definitiveness of formative lines of clothes in accordance with body joints and an emphasis on formative lines of clothes; the flattened space was marked by single layer structure, planarity of elements of clothes, and listing arrangement by appropriate proportion.; the completedness of the objects was expressed by the stationary state where overall image is fixed, the construction of homogeneous and complete space, and absolute inevitability of internal layout in proportion; lastly, organic harmony of independent parts was stressed in independent completedness of each detail, and organic harmony of the whole. The expressive features would lead to a unique expression style of linear emphasis, proportion, constructive forms, and two-dimensional arrangement. The meaning of this study is follows: The characteristics of art school of thought are given shape by appling & analysing the architectural layout principles of historical art school of thought to modern fashion in the view point of formal construction dimension. The applied possibility of historical art school of thought as the source of inspiration about the fashion design is extended.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.640-652
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• 1994

This work is undertaken to determine alcohol homologues so-called fusel oil that may be present in the Korean folk sojues (distilled liquor) made from grains and to describe sample preparation and analytical method by GC-FID-MS. Solid phase extraction method for sample preparation by using porous styrene divinyl benzene polymer (Porapak Q) was compared with steam distillation and solvent extraction method. Retention behaviors of homologous series of alcohols were also studied. Log values of retention time, molecular weight, boiling point, and capacity factor of alcohols showed linear correlations to the carbon number of an alcohol, to the oven temperature, and to the dielectric constant. Components such as methyl alcohol, n-propyl alcohol, isobutyl alcohol, isopentyl alcohol, and phenethyl alcohol have been identified. The more amount of isopentyl alcohol than other alcohols are contained in the Korean folk sojues, while that of n-propyl alcohol are contained in Chinese kaoliangchiew. Degree of similarity or dissimilarity and classification of the individual samples were discussed using multivariate statistical analysis(principal components analysis) based on GC data.

• Korean Journal of Materials Research
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• v.8 no.5
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• pp.377-382
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• 1998

Atomic layer deposition(ALD) of amorphous TiN films on $SiO_2$ between 17$0^{\circ}C$ and 21O$^{\circ}C$ has been investigated by alternate supply of reactant sources, Ti[N($C_2,H_5,CH_3)_2]_4$ [tetrakis(ethylmethylamminoltitanium: TEMAT] and $NH_3$. Reactant sources were injected into the reactor in the order of TEMAT vapor pulse, Ar gas pulse, $NH_3$. gas pulse and Ar gas pulse. Film thickness per cycle was saturated at around 1.6 monolayer(MU per cycle with sufficient pulse times of reactant sources at 20$0^{\circ}C$. The results suggest that film thickness per cycle could be beyond 1 MLicycie in ALD, which were explained by rechemisorption mechanisms of reactant sources. The ideal linear relationship be¬tween number of cycles and film thickness is confirmed. As a results of surface limited reactions of ALD, step cover¬age was excellent. Particles caused by the gas phase reactions between TEMAT and NH3 were almost free because TEMAT was seperated from $NH_3$ by the Ar pulse. In spite of relatively low substrate temperature, carbon impurity was incorporated below 4 at%.

• Applied Biological Chemistry
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• v.38 no.5
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• pp.435-439
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• 1995

Some characteristics and pathogenicity of Hyphantria cunea nuclear polyhedrosis virus (HcNPV), a potential microbial pesticide was studied. H. cunea NPV replicated in the nucleus of S. frugiperda cells cultured in the TNMFH medium. In case of virus infected cell, prepolyhedra formation was observed at 24hrs post-infection. At 48 hrs post-infection, Most of the infected cell contained many mature polyhedra which were released into culture media 72 hrs post-infection, with the cells grown in suspension culture, pH of the culture medium increased during the virus replication: the pH of fresh medium was 6.35 and rose to 6.77 within 120 hrs. Polyhedra formed a band in linear density gradient of sucrose by centrifugation, which co-sedimented with $50{\sim}55%$ sucrose. The shape of the purified polyhedra was mostly tetragonal hexahedron and its size was about $2.5{\mu}m$. Electron microscopy and phase contrast microscopy showed that many bundled nucleocapsids were occluded in mature polyhedra at 48 hrs post infection. H. cunea larvae infected with NPV showed a higher motality in the second and third instar than in the fourth instar. Death rate of H. cunea larvae in the second and third instar fed with leaves coated with $1.5{\times}10^{9}{\sim}l.5{\times}10^{7}PIBs/ml$ reached more than 90%.

• Archives of Pharmacal Research
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• v.26 no.1
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• pp.70-75
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• 2003

The objective of the present study was to investigate the uptake process of 4-Phenylazobenzoxycarbonyl-Pro-Leu-Gly-Pro-D-Arg (Pz-peptide), a hydrophilic and collagenase-labile pentapeptide, by isolated hepatocytes. For comparison, the uptake of Pz-peptide by Caco-2 cells and colonic cells, two known paracellular routes of Pz-peptide, was also evaluated. A simple and sensitive reversed-phase HPLC assay method using UV detection has been developed. The coefficient of variation for all the criteria of validation were less than 15%. The method was, therefore, considered to be sutable for measuring the concentration of Pz-peptide in the biological cells. Pz-peptide was extensively uptaked into hepatocytes. The initial velocity of Pz-peptide uptake assessed from the initial slope of the curve was plotted as Eadie-Hofstee plots. The maximum velocity ($V_{max}$) and the Michaelis constant ($K_m$) were 0.190$\pm$0.020 $nmol/min/10^6$ cells and 12.1$\pm$3.23 $\mu$M, respectively. The permeability-surface area product ($PS{influx}$) was calculated to be 0.0157 ml/min/10^6$ cells. $V_{max}$ and $K_m$ values for Caco-2 cells were calculated to be 6.22$\pm$0.930 pmol/min/10^6$ cells and 82.8$\pm$8.37 $\mu$M, respectively, being comparable with those of colonocytes (6.04$\pm$1.03 pmol/min/10^6$ cells and 87.8$\pm$13.2 $\mu$M, respectively). $PS_{influx}$ values for Caco-2 cells and colonocytes were calculated to be 0.0751 $\mu$l/min/10^6$ cells and 0.0688 $\mu$l/min/10^6$ cells, respectively. The more pronounced uptake of Pz-peptide by hepatocytes, when compared with Caco-2 cells and colonocytes, is probably due to its specific transporter. In conclusion, Pz-peptide, a paracellularly transported pentapeptide in the intestine and ocular epithelia, was uptaked into hepatocytes extensively. Although Pz-peptide is able to be uptaked into the Caco-2 cells and colonocytes, it is less pronounced when compared with hepatocytes. $PS_{influx}$ values of Caco-2 cells and colonocytes for unbound Pz-peptide under linear conditions were less than 0.4% when compared with that of hepatocytes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.265-274
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• 2011

In this paper, it is studied on wide radiating slot antenna's miniaturization for ultra wide-band(UWB) technologies and notch structure to prevent interference between UWB systems and existing wireless systems for using Wi-Fi service of IEEE standards 802.11 a/n. Proposed antenna that wide slot is decreased from $\lambda/2$ to $\lambda/4$ length of resonant frequency has decreased by 72 % compared with conventional antenna. And optimized T-shaped CPW-fed stub has satisfied UWB bandwidth for 3.0~11.8 GHz. Then, creating 2-order Hilbert curve slot line in the stub's patch area, 4.9~5.6 GHz that centered frequency is 5 GHz is eliminated. Finally, the designed antenna constructed on FR4-epoxy has $20{\times}15\;mm^2$ dimension. The measured results that are obtained return loss under -10 dB through 3.2~11.8 GHz without Wi-Fi bandwidth, a linear phase characteristic, a stable group delay, and omnidirectional radiation patterns are presented.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.19-29
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• 2002

The purpose of this study was to compare the polymerization shrinkage and the compressive strength of composite and compomer cured with two different light sources ; conventional halogen-light curing unit and recently-developed plasma arc curing unit. The 'strain gauge method' was used for determination of polymerization shrinkage and the compressive strength was measured by universal testing machine. The results of the present study can be summarized as follows: 1. Filling materials in polyethylene molds showed the initial expansion in the early phase of polymerization. This was followed by the rapid contraction in volume during the first 60 seconds and gradually diminished as curing process continued. 2. The polymerization shrinkage in tooth samples was generally lower than in the mold samples. 3. The generally lower amount of linear polymerization shrinkage was observed in compomer and plasma arc curing unit group when compared to composite and conventional curing unit. 4. The higher compressive strength values was found in composite groups regardless curing methods. The results of this study strongly support the application of plasma arc system and fluoride-containing compomer in the field of clinical pediatric dentistry claiming its effectiveness in curing the esthetic dental materials and the anticariogenic capacity.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.681-685
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• 2008

Chiral separation of racemic mandelic acid was achieved on a Kromasil KR100-5CHI-TBB column. Some chromatographic parameters (resolution, number of theoretical plates, capacity factor) are calculated under different separation conditions such as changes of mobile phase compositions (hexane/t-BME = 85/15 - 10/90) as well as formic acid concentrations for adjusting pH (0.1, 0.5, 1.0 v/v%). Flow rate versus number of theoretical plates was compared to evaluate column efficiency. To determine the adsorption isotherms, PIM (Pulse Input Method) was carried out. At the concentrations of racemic mandelic acid between 0.1 and 0.3 mg/ml, L- and D-mandelic acids have the same retention times of 8.8 and 9.4 min respectively. Mandelic acid isotherms show a linear form under the concentrations of 0.3 mg/ml with eluent (hexane/t-BME = 75/25). As the concentrations of mandelic acids increase, nonlinear Langmuir isotherms were observed as $C_{S,L}=3.358C_{M,L}/(1+0.0897C_{M,L})$ for L-mandelic acid and, $C_{S,D}=3.692C_{M,D}/(1+0.1457C_{M,D})$ for D-mandelic acid.