• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.2
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• pp.104-110
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• 2011

This study was conducted to improve the food functional and sensory food quality of Hizikia fusiforme by the fermentation of lactic acid bacteria. Seven strains of lactic acid bacteria isolated from traditional Korean fermented food were inoculated and cultivated in H. fusiforme water extract. Among them, Lactobacillus brevis LB-20, isolated from Kimchi, was selected for further study by considering the results of bacterial growth, DPPH radical scavenging activity, and sensory evaluation. No significant differences in proximate compositions (moisture, crude protein, crude fat, and crude ash) were observed by the fermentation of L. brevis LB-20. The most dramatical change was the conversion from glutamate to ${\gamma}$-aminobutyric acid (GABA) in H. fusiforme water extract fermented by L. brevis LB-20. The GABA content increased approximately 60-fold after 48 hr of fermentation. The bacterial fermentation also resulted in low-molecularization of the extract. The particle size of the fermented extract became approximately 4-fold smaller than that of the law extract. In addition, the analysis of volatile flavor compounds using GC/MS revealed that the bacterial fermentation dramatically removed off-flavors such as acetaldehyde, haxanal, diallyl disulphide and 1-penten-2-ol in the H. fusiforme extract.

• Restorative Dentistry and Endodontics
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• v.37 no.1
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• pp.41-49
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• 2012

Objectives: The internal adaptation of composite restorations with or without resin modified glass ionomer cement (RMGIC) was analyzed non-destructively using Microcomputed tomography (micro-CT). Materials and Methods: Thirty intact human teeth were used. The specimens were divided into 3 groups. In the control group, the cavities were etched with 10% phosphoric acid for 15 sec. Composite resin was filled into the cavity without adhesive. In group 1, light cured glass ionomer cement (GIC, Fuji II LC, GC) was applied as a base. The cavities were then etched, bonded, light cured and filled with composites. In group 2, the cavities were then etched, bonded, light cured and filled with composites without base application. They were immersed in a 25% silver nitrate solution. Micro-CT was performed before and after mechanical loading. One-way ANOVA with Duncan analysis was used to compare the internal adaptation between the groups before or after loading. A paired t-test was used to compare internal adaptation before and after mechanical loading. All statistical inferences were made within the 95% confidence interval. Results: The silver nitrate solution successfully penetrated into the dentinal tubules from the pulp spaces, and infiltrated into the gap between restoration and pulpal floor. Group 2 showed a lower adaptation than the control group and group 1 (p < 0.05). There was no significant difference between the control group and group 1. For all groups, there was a significant difference between before and after mechanical loading (p < 0.05). Conclusions: The internal adaptation before and after loading was better when composites were bonded to tooth using adhesive than composites based with RMGIC.

• Restorative Dentistry and Endodontics
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• v.41 no.4
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• pp.255-261
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• 2016

Objectives: This study aimed to analyze the mineral composition of naturally- and artificially-produced caries-affected root dentin and to determine the elemental incorporation of resin-modified glass ionomer (RMGI) into the demineralized dentin. Materials and Methods: Box-formed cavities were prepared on buccal and lingual root surfaces of sound human premolars (n = 15). One cavity was exposed to a microbial caries model using a strain of Streptococcus mutans. The other cavity was subjected to a chemical model under pH cycling. Premolars and molars with root surface caries were used as a natural caries model (n = 15). Outer caries lesion was removed using a carbide bur and a hand excavator under a dyeing technique and restored with RMGI (FujiII LC, GC Corp.). The weight percentages of calcium (Ca), phosphate (P), and strontium (Sr) and the widths of demineralized dentin were determined by electron probe microanalysis and compared among the groups using ANOVA and Tukey test (p < 0.05). Results: There was a pattern of demineralization in all models, as visualized with scanning electron microscopy. Artificial models induced greater losses of Ca and P and larger widths of demineralized dentin than did a natural caries model (p < 0.05). Sr was diffused into the demineralized dentin layer from RMGI. Conclusions: Both microbial and chemical caries models produced similar patterns of mineral composition on the caries-affected dentin. However, the artificial lesions had a relatively larger extent of demineralization than did the natural lesions. RMGI was incorporated into the superficial layer of the caries-affected dentin.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.612-617
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• 1995

Changes in titratable acidity, pH, viable cells, sensory properties and volatile aroma compounds of yogurt during lactic fermentation in milk added with egg white powder (EWP) have been studied. Milk added with 1% or 2% (W/V) of EWP was fermented with Lactobacillus acidophilus for 30 hr. Acidity of milk added with EAT increased gradually during lactic fermentation for 30 hr, pH dropped gradually and number of viable cells increased and reached stationary phase at about 9 hr. Addition of EWP significantly stimulated acid production by lactic acid bacteria and stimulating effect of 2% EWP addition on acid production was slightly higher than that of 1% EWP addition. Sensory evaluation showed that optimum fermentation time of yogurt prepared from milk added with 2% of EWP was about 15 hr. Gas chromatographic analysis showed that the amount of acetone and butanol decreased gradually and that of ethanol increased until 30 hr. Diacetyl and acetoin were first detected after 6hr and 9hr, respectively, and then increased until 30 hr.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.458-463
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• 1995

A curd yogurt was prepared from milk added with skim milk powder or egg white powder(EWP). The effects of EWP addition on growth and acid production by lactic acid bacteria in milk were studied. The effects of EWP addition on quality of curd yogurt in point of apparent viscosity, sensory property and volatile aroma compounds were also investigated. Addition of PAT markedly stimulated acid production by lactic acid bacteria and stimulating effect of EWP on acid production was proportional to the amount of addition. Apparent viscosity of curd yogurt added with EWP was generally higher than that of control. Curd yogurt fermented with L. acidophilus showed thixotropic characteristics. Sensory property of curd yogurt added with EWP was evaluated as better than reference sample and sample added with EWP at 2% level was evaluated as better than other samples. Acetone, ethanol, diacetyl, butanol and acetoin were detected by gas chromatographic analysis.

• Preventive Nutrition and Food Science
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• v.16 no.3
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• pp.230-235
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• 2011

Roasted and retorted (RR) chestnuts develop green pigment spots on their surface during storage. The purpose of this study was to evaluate the cytotoxicity of the green pigment using RAW 264.7, MOLT-4, KATOIII and HT-29 cells. The pigment scraped from RR chestnuts (GP), whole RR chestnuts with green pigment spots (GC), whole RR chestnuts without green pigment (WC) and roasted and frozen stored chestnuts (FC) were extracted in 10% DMSO. MOLT-4 cells were less resistant to the cytotoxicity of the chestnut extracts than the RAW 264.7 cells. The GP extracts did not show different responses against $H_2O_2$-induced oxidative stress and LPS-induced NO production compared to the other extracts. The chestnut extracts did not have proliferative activity on either of the KATOIII or HT-29 cells (p>0.05). Our results from the comparison of the green pigment produced on the surface of the RR chestnuts to chestnuts that do not develop the green pigment suggest that the pigment may not be harmful in terms of either cytotoxicity towards immune cells or proliferation of gastrointestinal cancer cells.

• Food Science and Preservation
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• v.21 no.2
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• pp.224-230
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• 2014

Brazil (Monte Alegro) and Ethiopia (Sidamo) coffee beans were roasted at three different roasting levels(light, medium, and dark), and were analyzed for color, total phenolic compound, caffeine, and chlorogenic acid contents. The total phenolic and caffeine contents remained unchanged during roasting. The chlorogenic acid levels of the Brazil and Ethiopia samples decreased with roasting. The antioxidant activities were measured using DPPH and ABTS. The radical scavenging activities of the light-roasted and dark-roasted coffee beans were similar. The flavor patterns of roasted coffee beans were analyzed using an electronic nose system based on gas chromatography. The data revealed that the flavor patterns of the roasted coffee beans could be separated via discriminant function analysis (DFA) method. The taste of the roasted coffee beans was analyzed using an electronic tongue system. The sourness and sweetness were decreased with roasting.

• Magazine of the Korea Concrete Institute
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• v.9 no.2
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• pp.121-132
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• 1997

The thermal behavior of' concrete can be ch;lracterized from a knowledge of concrete ternperatu1.e at early ages, environmental conditions, and cement hydration in the mixture. 'l'o account for thost. interactions, a computer model was developed for prwlicting the temperature pr.ol'ile in hnrdcning c o n c r c t ~ st.r~icture in terms of material and tmvironmcntal factors. The cerncnt hydration cha~.acteristics such as the activating energy, total heat 1ihei.atr.d. anti th\ulcorner degree of' hydration. can represent the internal heat gc,neration. In this study. th(> activating c1ncrgy and the tlcgree of' hydration curve were determined well fmm the rnortn~. compressive strength tests while total amount of heat liberated was determined by tht> isothermal calorimctcr method. The main purpose of' this study is to correlate measured tt>mperaturr distributions in a concrete st1,ucture during thc hardening process with the ~ c s u l t s computed f'ro~n theoretical considrl.ations. Using twodimensional heat transfer model, first. the importance of several parameters will be identified by a parametric analysis. Then, the tcmpcmture distribution of thc cylindrical concrete specimen in the laboratory was mensuwti and compared with that yielded by thc theoretical considel.ations.

• The Korean Journal of Ecology
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• v.22 no.1
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• pp.59-63
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• 1999

To verify allelopathic effects, seed germination and seedling growth test, chemical analysis and bioassay of selected species were carried out with naturally occurring chemicals of Artemisia capillaris. Seed germination ratio of Calamagrostis arundinacea. Youngia denticulata and Lactuca indica var. laciniata showed decrease in proportion to increase in aqueous extracts concentration of A. capillaris. while that of Cosmos bipinnatus and Leonurus sibiricus did not. However, dry weight growth of selected species treated with the same extracts as the above experiment was inhibited remarkably compared to the germination test. In the test at different concentrations of essential oil from A. capillaris, seedling growth of A. princeps var. orientalis and Plantago asiatica was suppressed according to the concentration of the essential oil, and root growth of the selected species was more inhibitory than that of shoot growth. Thirty-six chemical compounds were identified from A. capillaris plant by gas chromatography. Seven compounds out of 36 were bioassayed, and terpinen-4-ol was the most toxic among the tested substances.

• Journal of Environmental Science International
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• v.11 no.4
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• pp.375-382
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• 2002

The total hydrocarbon distribution of oil products obtained from the pyrolysis of four kinds of mixtures of polyethylene-polystyrene waste has been studied by multidimensional chromatography(high performance liquid chromatography followed by capillary gas chromatography)/mass spectrometry. Saturated, unsaturated and aromatic hydrocarbons in oil products were selectively pre-separated according to structural groups by HPLC and the weight fraction of each group was estimated by analysis of each component using GC-FID response factors. The hydrocarbon distribution of aliphatic fraction consists of $C_{5}$ to $C_{25}$ saturated and unsaturated hydrocarbons. And that of aromatics fraction consists of benzene, toluene, xylene, styrene, propenyl benzene, naphthalene, and some of derivatives. Pyrolysis temperature did not affect the ratio of total weight fraction of aliphatic over aromatic hydrocarbon distribution in case of PS only and PE-PS mixtures (1:1 and 1:4 wt. ratio) as a feed while affected the ratio of total wt. fraction in case of PE only. The optimal temperature for the maximum oil production was $600^{\circ}C$ for pyrolysis of PS and 1:1 and 1:4 mixtures of PE and PS. The optimal condition for aromatic recovery was $600^{\circ}C$ with 1:1 mixture of PE and PS. In this condition, aromatic was produced up to 90% of total oil product. The maximum yield of toluene, xylene, styrene, and propenyl benzene were 8.6, 8.9, 51.0 and 7.4% of feed for pyrolysis PS at $700^{\circ}C$, respectively. However, only 1.3% naphthalene was recovered at $700^{\circ}C$ with 1:1 PE:PS(by wt.).