• The Journal of Korean Academy of Prosthodontics
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• v.43 no.4
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• pp.466-477
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• 2005

Statement of problem : Problem of matching the appearance of porcelain restorations with the patient's natural dentition has always been a concern to dental clinicians. Recently, demands for esthetics, even in restorations requiring strength, has brought a revolution to dentistry and increased use of zirconia. Among the various factors, shade and translucency or the core can significantly affect the overall esthetics of the restoration and should be considered when selecting an all-ceramic system. Purpose : The purpose of this study was to spectrophotometrically evaluate the influence of different zirconia systems and core thickness on the final shade of all-ceramic restorations using the CIEL$^*a^*b^*$ system. Material and Methods: Core specimens (n : 20 per group) of In-Ceram Alumina, In-Ceram Zirconia, Digident CAD/CAM Zirconia, Cercon Zirconia were fabricated 20mm in diameter. 10 specimens of each group were fabricated at core thickness of 0.5mm and 0.7mm. These core specimens were veneered with shade Al & A3 porcelain of the recommended manufacturer. CIEL$^*a^*b^*$ coordinates were recorded for each specimen with a spectrophotometer (Model CM-2600d, Minolta, Japan). Color differences were calculated using the equation ${\Delta}E^*=[({\Delta}L^*)^2+({\Delta}a^*)^2+({\Delta}b^*)^2]^{\frac{1}{2}}$. Results : 1. Specimens of core thickness 0.5mm and 0.7mm did not exhibit clinically perceived color difference. 2. Regarding shade reproducibility, In-Ceram Alumina and In-Ceram Zirconia showed significant difference within each group. 3. Cercon Zirconia group showed the highest $L^*$ value and Digident Zirconia group showed lowest $a^*$ & $b^*$ value. 4. Generally the shade difference between materials was higher in the A3 shade group than in the Al shade group. Conclusion: Within the limitations of this study, there was no color difference after increase in core thickness and every all-ceramic system has color characteristics that clinicians have to consider when selecting materials. Also, manufacturers of different porcelain systems must make every effort to achieve color reproducibility.

• Korean Journal of Medicinal Crop Science
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• v.9 no.1
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• pp.40-44
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• 2001

DPPH(1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and Vitamin contents in different plant parts and harvesting time of Rosa rugosa Thunb were determined. Among the plants parts analysed, the highest DPPH radical scavenging activity in part was root $(below\;0.5\;{\mu}g/ml)$, leaf contained the highest ascorbic acid content of 2999.6 mg/100g. Fruit contained ascorbic acid (713.6 mg/ 100g) 4.2 times less than leaf. Vitamin contents in leaf parts also differed depanding on harvesting time. Vitamin content in leaf harvested in November was much higher than that in September. Spectrophotometric analysis of total ${\beta}-carotene$ in leaf showed lower contents than that in fruit.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.612-622
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• 2014

In this study, we investigated the solubilization 4-chlorobenzoic acid in a wide range of temperature using a zwitterionic surfactant of lauryl sulfobetaine(LSB) and mixed surfactant systems. The effects of temperature and alkyl-group's length of surfactant molecule on the solubilization of 4-chlorobenzoic acid have been measured. The solubilization constants ($K_s$) were taken by the UV/Vis spectrophotometric method, plotting the total absorbance of the solution versus the surfactant concentration. The results show that the values of ${\Delta}G^o_s$ are all negative within the measured temperature range and decrease by increasing temperature, And also the measured values of ${\Delta}H^o_s$ and ${\Delta}S^o_s$ are all positive and increase by increasing temperature. The values of $K_s$ and thermodynamic parameters are simultaneously dependent on the temperature and the kinds of surfactant molecules. From the results we can postulate the solubilization site of 4-chlorobenzoic acid within the micelle.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.512-519
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• 1991

The axial ligations of nitrogenous bases (pyridine, imidazole, 1-methylimidazole and 2,6-lutidine) to Zn(II)-, Cu(II)-, and Ni(II)-tetrakis(o-chlorophenyl)porphyrin(o-ClTPP), and -tetraphenylporphyrin (TPP) were investigated in organic solvents $(CH_2Cl_2,\;C_6H_6,\;CH_3NO_2,\;(CH_3)_2CO,\;CHCl_3,\;DMF\;and\;DMSO)$ and at 0.01M of ionic strength. The equilibrium constants for the ligation reactions of methalloporphyrins were determined using spectrophotometric method at 15∼35${\circ}C$. In case of M(II)-TPP the equilibrium constants K were considerably larger than those of M(II)-(o-Cl)TPP, depending on steric effect of the porphyrin. The linear relationships between logK of the axial ligation and $pK_a$ of nitrogenous base were shown in M(II)-TPP, but not in M(II)-(o-Cl)TPP. The stabilities of MTPP(L) were controlled by the reation enthalpy and entropy, while those of M(o-Cl)TPP almost by the reaction entropy. The coordinating power of solvent to the methalloporphyrin were also studied in $CHCl_3,\;(CH_3)_2CO$, DMF and DMSO. From those results the solvent effects on the equilibrium constants were discussed.

• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1460-1468
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• 2007

In this study, an approx. 2.5-kb gene fragment including the catalase gene from Rhodospirillum rubrum S1 was cloned and characterized. The determination of the complete nucleotide sequence revealed that the cloned DNA fragment was organized into three open reading frames, designated as ORF1, catalase, and ORF3 in that order. The catalase gene consisted of 1,455 nucleotides and 484 amino acids, including the initiation and stop codons, and was located 326 bp upstream in the opposite direction of ORF1. The catalase was overproduced in Escherichia coli UM255, a catalase-deficient mutant, and then purified for the biochemical characterization of the enzyme. The purified catalase had an estimated molecular mass of 189 kDa, consisting of four identical subunits of 61 kDa. The enzyme exhibited activity over a broad pH range from pH 5.0 to pH 11.0 and temperature range from $20^{\circ}C$ to $60^{\circ}C$C. The catalase activity was inhibited by 3-amino-1,2,4-triazole, cyanide, azide, and hydroxylamine. The enzyme's $K_m$ value and $V_{max}$ of the catalase for $H_2O_2$ were 21.8 mM and 39,960 U/mg, respectively. Spectrophotometric analysis revealed that the ratio of $A_{406}$ to $A_{280}$ for the catalase was 0.97, indicating the presence of a ferric component. The absorption spectrum of catalase-4 exhibited a Soret band at 406 nm, which is typical of a heme-containing catalase. Treatment of the enzyme with dithionite did not alter the spectral shape and revealed no peroxidase activity. The combined results of the gene sequence and biochemical characterization proved that the catalase cloned from strain S1 in this study was a typical monofunctional catalase, which differed from the other types of catalases found in strain S1.

• Journal of Society of Preventive Korean Medicine
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• v.8 no.2
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• pp.81-98
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• 2004

1. The cell viability was determined by MTT method. Their cytotoxic activities against three cancer cell lines such as A549, MDA-MB-231 and SNU-C4 cell line were tested. Among them, The methanol extract of Saururus chinensis Baill. showed the strongest cytotoxic effect against SNU-C4 cells. These results suggest that the methanol extract of Saururus Chinensis Baill. possessed a potential antitumorous agent. 2. In vitro the antitoxic activity of ethanol extract of Saururus Chinensis Bail on NIH 3T3 fibroblasts was evaluate by the MTT (3-(4,5-dimethyl- thiazol-2-yl)-2,5-diphenyl-2H-tetra캐lium bromide) and SRB (sulforhodamine B protein) assays. The number of NIH 3T3 fibroblasts were increased and tend to regenerate. These results suggest that Saururus Chinensis Bail extract retains a potential antitoxic activity. 3. Complexation of Cd (II) ion with ligands such as quercetin has been determined by UV-vis spectrophotometric method in tris buffer solution at various pH. It was found that only 1 : 1 Cd-complex is formed by the interaction between catechol moiety in ring B and cadmium [Cd(II)] in aqueous solution. The spectral parameters for Cd-complex were determined by Beer's law at various pH. It has shown that 1 : 1 Cd-complex has a maximum absorbance and red shift by the alkaline pH.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.1-7
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• 2001

We investigated the capability of the phosphate-solubilizing fungus, Penicillium sp. GL-101, to solubilize in vitro some insoluble rock phosphate via possible mechanisms: acidification of the medium, production of chelating metabolites, redox activity, and so on. GL-101 was able to solubilize rock phosphate (mostly calcium phosphate) in a liquid potato dextrose broth(PDB) medium, as determined by spectrophotometric analyses. Acidification was the major mechanism of solubilization since the pH of cultures fell below 4.0 and in cultures containing 1.0%(w/v) loess the pH dropped from 7.0 to 3.2. More than 10 mg/mL concentrations of citric acids were detected by high-performance liquid chromatography(HPLC) in the culture supernatants. Also this fungus showed the phosphatase activity (over 1.3 unit) to contribute partially releasing phosphate from rock phosphate, when supplemented with 1.0% loess in culture broth. The chelating activity of GL-101 in culture supernatants was not present because 2-ketogluconic acid, a chelating agent for the phosphate, was produced only a basal level. Therefore, the solubilization mechanism of rock phosphate by Penicillium sp. GL-101 involves both acidification due to citric acid production and phosphatase activity.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.259-265
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• 2012

In this study, we determined total polyphenol content(TPC) and total flavonoid content(TFC) of extracts from Korean cabbage and cabbage using a spectrophotometric method as well as glucosinolates concentration by HPLC. TPCs of Korean cabbage and cabbage extracts were 308.48 ${\mu}g$ GAE/g dry weight and 344.75 ${\mu}g$ GAE/g dry weight, respectively. TFCs of Korean cabbage and cabbage extracts were 5.33 ${\mu}g$ QE/g dry weight and 5.95 ${\mu}g$ QE/g dry weight, respectively. We found six different glucosinolates, namely progoitrin, glucoalyssin, gluconapin, glucobrassicanapin, glucobrassicin and 4-methoxyglucobrassicin in the Korean cabbage extract. In the cabbage extract, there was four glucosinolates, namely glucoraphanin, sinigrin, glucobrassicin and 4-methoxyglucobrassicin. We determined the cytotoxic effect of Korean cabbage and cabbage extracts in AGS human stomach cancer cells, HepG2 human hepatic cancer cells and LNCaP human prostate cancer cells by MTT assay. Dose-dependent relationships were found between the extract concentrations and cancer cell growth inhibition. The overall results support that both Korean cabbage and cabbage, the major vegetables in Korea, contain bioactive compounds such as polypheol, flavonoids as well as glucosinolates and they may play a positive role in cancer prevention.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.3 s.52
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• pp.273-277
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• 2005

This study was performed to develop new cosmeceutical agents with sebosuppressive activity from native plant extracts in Korea. Inhibitory efforts of the extracts on $5{\alpha}-reductase$ (5-AR) were evaluated by enzyme kinetics analysis using UV-spectrophotometric method. Two kinds of enzyme suspensions as 5-AR sources were prepared from rat liver tissue and cultured hSG cells. The sebosuppressive effects were determined by measuring the total lipid quantity produced in cultured hSG cells after incubation with the extracts. As a result, Pinus thunbergii extracts showed the most potent 5-AR inhibitory effects. Its $K_i$ values were 0.0002% and 0.0014% for rat liver 5-AR and human sebaceous gland 5-AR, respectively. Addition of Pinus thunberii extract to hSG cells showed 48% reduction in total lipid production at 0.005% concentration. In conclusion, Pinus thunbergii extracts can be used as a cosmeceutical agent to regulate sebum production and to alleviate the sebum-involved skin diseases, such as acne and seborrheic dermatitis.

• Food Science and Preservation
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• v.19 no.5
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• pp.751-756
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• 2012

Antioxidant capacity and acetylcholinesterase (AChE) inhibitory activity of the aqueous methanolic extract of Rhus javanica were investigated in vitro. The antioxidant properties was measured by radical scavenging assays using DPPH and $ABTS^+$ radicals. The AChE inhibitory efficacy of R. javanica was tested by Ellman's assay and the total phenolic content was determined using a spectrophotometric method. All tested samples showed a dose-dependent AChE inhibitory and radical scavenging activities. In particularly, ethyl acetate (EtOAc)-soluble portion from the methanolic extract of R. javanica showed significantly higher inhibitory activity than other organic solvent soluble-portions in an AChE and radical scavenging assay systems. These results suggest that R. javanica may be possess potential benefits which might be useful in development of antioxidant and anti-alzheimer's disease ingredient.