• The Journal of Advanced Prosthodontics
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• v.11 no.5
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• pp.239-246
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• 2019

PURPOSE. The purpose of this study was to propose and assess a shade guide for pink gingival aesthetics using a Spanish population sample. MATERIALS AND METHODS. The $L^*$, $C^*$, h, $a^*$ and $b^*$ coordinates of 259 participants were measured using a spectrophotometer in 3 standardized points along the attached gingiva of the maxillary central incisors. A hierarchical clustering analysis was applied to obtain separate solutions regarding the number of shade tabs. For each of the solutions obtained, color differences (${\Delta}E^*$) were calculated using the CIELab and CIEDE2000 formulas, and the proposed shade guide was selected considering (1) the color differences between tabs and (2) the coverage error of each of the solutions. RESULTS. The proposed shade guide consisted of 8 gingival shade tabs and achieved CIELab and CIEDE2000 coverage errors of less than the respective 50:50% acceptability thresholds (${\Delta}E^*=4.6$ units and ${\Delta}E_{00}=4.1$). The coordinates for the various gingival shade tabs were as follows: Tab 1: $L^*43.3$, $a^*21.9$, $b^*12.3$ (1.6); Tab 2: $L^*42.9$, $a^*34.1$, $b^*19.1$; Tab 3: $L^*46.5$, $a^*25.8$, $b^*10.9$; Tab 4: $L^*46.5$, $a^*27.3$, $b^*15.1$; Tab 5: $L^*49.6$, $a^*23.5$, $b^*16.8$; Tab 6: $L^*51.5$, $a^*19.7$, $b^*13.6$; Tab 7: $L^*55.9$, $a^*22.0$, $b^*15.0$; and Tab 8: $L^*56.0$, $a^*19.9$, $b^*18.8$. CONCLUSION. The CIELab and CIEDE2000 coverage errors for the 8 shade tabs of the proposed gingival shade guide were significantly lower than those of other guides. Therefore, despite the limitations of this study, the proposed guide is more appropriate for matching gingival shade in the Spanish general population.

• The Korea Journal of Herbology
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• v.29 no.2
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• pp.15-21
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• 2014

Objectives : The purpose of this study was to investigate inhibitory effects of steamed Polygonatum odoratum extract (POE) on differentiation and adipogenesis in 3T3-L1 adipocytes. Methods : Polygonatum odoratum (P. odoratum) extract was extracted with ethyl acetate. Total phenolic and flavonoid contents in POE were measured for antioxidant activity. The spectrophotometric method was used to determine the DPPH and ABTS radical scavenging activity and ferric-reducing antioxidant potential (FRAP). MTT assay was examined for cell toxicity, oil red O staining was performed for intracelluar adipogenesis in differentiated 3T3-L1 adipocytes. Western blot analysis for measurement of CCAAT/enhancer-binding protein ${\alpha}$ ($C/EBP{\alpha}$), peroxisome proliferator-activated receptor${\gamma}$ ($PPAR{\gamma}$) and AMP-activated protein kinase (AMPK) expressions were performed. Results : The results revealed that POE has antioxidant activities. Contents of total polyphenolics and flavonoids were $50.83{\pm}1.52$ GAE mg/100g dry weight of POE and $17.05{\pm}2.47$ RE mg/100g dry weight of POE, respectively. DPPH radical scavenging activity, and FRAP in 10 mg/ml concentration were $92.1{\pm}0.6%$, $244.8{\pm}9.0{\mu}M$ Fe(II) and ABTS inhibition in 5 mg/ml concentration was $84.8{\pm}4.1%$. Treatment of POE in adipocytes inhibited the differentiation and adipogenesis of 3T3-L1 adipocytes compared to those of vehicle control. Additionally, protein expressions of $C/EBP{\alpha}$ and $PPAR{\gamma}$, major transcription factor for the adipogenic genes, were significantly decreased compared to those of vehicle control (p<0.05). Futhermore, phosphorylation of AMPK was increased in 3T3-L1 adipocytes treated with POE compared to that of vehicle control (p<0.05). Conclusions : we demonstrate that steamed P. odoratum extract (POE) has potentiating antioxidant activities, inhibits differentiation and lipid accumulation and also induces energy expenditure in adipocytes, which may contribute to antiobesity property.

• Food Science and Preservation
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• v.22 no.2
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• pp.275-280
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• 2015

Among the naturally occurring antioxidants, polyphenols are widely distributed in various fruits, vegetables, wines, juices, and plant-based dietary sources and divided into several subclasses that included phenolic acid, flavonoids, stilbenes, and lignans. As part of our continuing search for bioactive food ingredients, the antioxidant and ${\alpha}$-glucosidase inhibitory activities of the aqueous ethanolic extract from the aerial parts of Ainsliaea acerifolia were investigated in vitro. The antioxidant properties were evaluated via radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals. In addition, the anti-diabetic effect of A. acerifolia extracts was tested via ${\alpha}$-glucosidase inhibitory assay. Furthermore, the total phenolic contents were determined using a spectrophotometric method. All the tested samples showed dose-dependent radical scavenging and ${\alpha}$-glucosidase inhibitory activities. In particularly, the ${\alpha}$-glucosidase inhibitory and radical scavenging properties of the ethyl acetate (EtOAc)-soluble portion from the aerial parts of the A. acerifolia were higher than those of the other solvent-soluble portions. These results suggest that A. acerifolia could be considered a new potential source of natural antioxidants and antidiabetic ingredients. More systematic investigation of the aerial parts of A. acerifolia will be performed for the further development of anti-oxidative and antidiabetic drugs.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.4
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• pp.409-419
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• 2008

Statement of problem: At all times people have tried to fabricate tooth restorations using tooth colored materials. Recently, demands for esthetics, even in restorations requiring strength, has brought a revolution to dentistry and increased use of zirconia. The basic color of zirconia is white to ivory. The color can be partially adapted by veneering it with ceramic materials. However, it would be better if the substructure could already be adapted to the basic color shade of neighboring teeth. By adaptation to the basic shade, it can help to reduce the necessary layer thickness of the veneer ceramic to achieve the desired color. Purpose: The purpose of this study was to spectrophotometrically evaluate the influence of shading of zirconia core on the final shade of all-ceramic restorations using the CIE $L^{*}a^{*}b^{*}$ system. Material and methods: Core specimens (n = 20 per group) of Lava Frame Zirconia, KaVo Everest Zirconia, Digident CAD/CAM Zirconia were fabricated at 20 mm in diameter and 0.5 mm in thickness. Halves of each groups were shaded in A3 color. These core specimens were veneered with A3 porcelain of the recommended manufacturer at thickness of 0.5 mm. CIE $L^{*}a^{*}b^{*}$ coordinates were recorded for each specimen with a spectrophotometer (Model CM-2600d, Minolta, Japan) at 0.5 mm, 0.4 mm, 0.3 mm in thickness. Color differences were calculated using the equation ${\Delta}E^{*}=[({\Delta}L^{*})2+({\Delta}a^{*})2+({\Delta}b^{*})2]1/2$. Results: 1. In the case where porcelain layer has a thickness of 0.5 mm, Lava Frame Zirconia and KaVo Everest group did not show clinically perceived color difference, however Digident CAD/CAM Zirconia group showed clinically perceived color difference according to shade allowed on core. 2. When the thickness of porcelain layer decreased from 0.5 mm to 0.4 mm, Lava Frame Zirconia and KaVo Everest group did not show clinically perceived color difference, on the other hand Digident CAD/CAM Zirconia group showed clinically perceived color difference according to shade allowed on core. 3. When the thickness of porcelain layer decreased from 0.5 mm to 0.3 mm, clinically perceived color differences were observed from all three groups. Conclusions: Ziroconia system, which is possible to allow shade on core, are thought to be much more favorable to reproduce natural shade compared to systems that is impossible to give shade. Therefore, clinicians ought to choose adequate system for certain clinical situation by considering above specific character.

• Journal of the Korean Chemical Society
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• v.31 no.4
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• pp.334-343
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• 1987

The Chemical reactions between $NiL_m{^{2+}}\{$Ni(rac-1[14]7-diene)^{2+},\;Ni(meso-1[14]7-diene)^{2+},\;Ni(1[14]4-diene)^{2+},\;{\alpha}-Ni(rac-[14]-decane)^{2+},\;{\beta}-Ni(rac-[14]-decane)^{2+},\;and\;Ni(meso-[14]-decane)^{2+}$}\and\ CN^-$ ion were studied by the spectrophotometric method. The equilibrium constants (K_1$) for the 1:1 complex ion, $[NiL_m(CN)]^+\;with\;NiL_m{^{2+}}\;and\;CN^-$ ion were determined in the range of 3 to $25^{\circ}C$. The $K_1\;for\;Ni(rac-1[14]7-diene)^{2+},\;Ni(meso-1[14]7-diene)^{2+},\;Ni(1[14]4-diene)^{2+},\;{\alpha}-Ni(rac-[14]-decane)^{2+},\;{beta}-Ni(rac-[14]-decane)^{2+},\;and\;Ni(meso-[14]-decane)^{2+}\;at\;15^{\circ}C$ was 4.7, 5.3, 6.2, 7.5, 9.4, and 9.8, respectively. The values of $K_1$ decreased with increasing temperature. From the temperature effect on equilibrium constant ($K_1$), thermodynamic parameters $({\Delta}H^{\circ},\;{\Delta}S^{\circ},\;{\Delta}G^{\circ})$ for reaction were evaluated and the reaction of $NiL_m{^{2+}}\;and\;CN^-$ ion was exothermic. $NiL_m{^{2+}\;reacts\;with\;CN^-$ ion to give $Ni(CN)_4{^{2-}}$ ion and macrocyclic ligand $(L_m)$. The kinetics of formation of the $Ni(CN)_4{^{2-}}$ ion of varying the $[CN^-],\;[HCN],\;and\;[OH^-]$ have been investigated at 3∼$25^{\circ}C\;and\;0.5M\;NaClO_4$. Maintaining a constant $[CN^-],\;k_{obs}/[CN^-]^2$ increases linearly with increasing [HCN]. In the presence of large quantities of $[OH^-],\;k_{obs}/[CN^-]^2$ also increases linearly with $[OH^-]$. From the temperature effect on kinetic constant (k_{obs})$, parameter of activation $({\Delta}H^{\neq},\;{\Delta}S^{\neq})$ of reaction of $NiL_m{^{2+}}\;with\;CN^-$ ion were determined. For the $Ni(rac-1[14]7-diene)^{2+},\;Ni(meso-1[14]7-diene)^{2+},\;{\alpha}-Ni(rac-[14]-decane)^{2+},\;{\beta}-Ni(rac-[14]-decane)^{2+},\;and\;Ni(meso-[14]-decane)^{2+}\;series\;{\Delta}H^{\neq}$ gradually decrease as the d-d transition energy, $ν(cm^{-1})$ decrease. And the reaction of the five $NiL_m{^{2+}}\;with\;CN^-$ ion take place by way of equal paths.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.8
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• pp.1206-1211
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• 2015

Grape juice is consumed worldwide and studied due to the high antioxidant activities and contents. The color of grape juice is due to the presence of phenolic compounds such as anthocyanins. Therefore, color values can be an indicator of antioxidant capacities of grape juice. However, the correlation between color values and antioxidant activities in grape juice has not been well studied. In this study, the physicochemical characteristics and correlation between color values and antioxidant capacities of Korean red grape juices (five commercial juices from market and two juices prepared in the laboratory) were investigated to estimate antioxidant capacities. Antioxidant capacities were determined by 1,1-diphenlyl-2-picrylhydrazyl radical scavenging assay, ferric ion reducing antioxidant power assay, and oxygen radical absorbance capacity assay. Total phenolic contents, total flavonoid contents, and total anthocyanin contents, including five kinds of polyphenolic compounds, were examined by high performance liquid chromatography (HPLC). The results for physicochemical properties showed similar values, except titratable acidity. The color hue values of the prepared juices were higher than those of commercial juices, which was in contrast to the lower color intensity values (P<0.05). The Hunter L, a, and b values showed almost no difference between commercial and prepared juices. The antioxidant activities and total phenolic contents of commercial juices were higher than those of prepared ones. Gallic acid, catechin, and quercetin were confirmed by HPLC in all samples. The total phenolic and total flavonoid contents showed positive correlation with antioxidant activities. In addition, antioxidant activities and contents correlated with color values. Thus, estimation of antioxidant capacity could be feasible through the spectrophotometric measurement of color values.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.5
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• pp.731-738
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• 2011

Cholesterol is the precursor of various steroid hormones, bile acid, and vitamin D with functions related to regulation of membrane permeability and fluidity. However, the presence of excess blood cholesterol may lead to arteriosclerosis and hypertension. Moreover, dietary cholesterol may affect blood cholesterol levels. Generally, cholesterol determination is performed by spectrophotometric or chromatographic methods, but these methods are very time consuming and costly, and require complicated pretreatment. Thus, the development of a rapid and simple analysis method for measuring cholesterol concentration in food is needed. Multi-walled carbon nanotube (MWCNT) was functionalized to MWCNT-$NH_2$ via MWCNT-COOH to have high sensitivity to $H_2O_2$. The fabricated MWCNT-$NH_2$ was attached to a glassy carbon electrode (GCE), after which Prussian blue (PB) was coated onto MWCNT-$NH_2$/GCE. MWCNT-$NH_2$/PB/GCE was used as a working electrode. An Ag/AgCl electrode and Pt wire were used as a reference electrode and counter electrode, respectively. The sensitivity of the modified working electrode was determined based on the amount of current according to the concentration of $H_2O_2$. The response increased with an increase of $H_2O_2$ concentration in the range of 0.5~500 ${\mu}M$ ($r^2$=0.96) with a detection limit of 0.1 ${\mu}M$. Cholesterol oxidase was immobilized to aminopropyl glass beads, CNBr-activated sepharose, Na-alginate, and toyopearl beads. The immobilized enzyme reactors with aminopropyl glass beads and CNBr-activated sepharose showed linearity in the range of 1~100 ${\mu}M$ cholesterol. Na-alginate and toyopearl beads showed linearity in the range of 5~50 and 1~50 ${\mu}M$ cholesterol, respectively. The detection limit of all immobilized enzyme reactors was 1 ${\mu}M$. These enzyme reactors showed high sensitivity; especially, the enzyme reactors with CNBr-activated sepharose and Na-alginate indicated high coupling efficiency and sensitivity. Therefore, both of the enzyme reactors are more suitable for a cholesterol biosensor system.

• Journal of the Korean Chemical Society
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• v.31 no.2
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• pp.168-177
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• 1987

The equilibria of chemical reaction between $\alpha$-Ni(rac-[14]-decane)$^{2+}$ and polar solvents(L; ANT, MFA, DMSO, DMF, and DMA) have been investigated by the spectrophotometric method at $25^{\circ}C$. (The equilibrium constants($K_1$) of) the first step in ANT, MFA, DMSO, DMF, and DMA were 31.0, 27.5, 21.3 15.9, and 6.4, respectively. The smallness of equilibrium constants ($K_2$) of the second step compared with $K_1$, was observed. $\alpha$-Ni(rac-[14]-dacane)$^{2+}$ + L $\leftrightharpoons$ [$\alpha$-Ni(rac-[14]-decane){\cdot}L]$^{2+}$ : $K_1$.[$\alpha$-Ni(rac-[14]-decane){\cdot}L)$^{2+}$+ L $\leftrightharpoons$ [$\alpha$-Ni(rac-[14]-decane){\cdot}$L_2$)$^{2+}$ :$K_2$. The relationship between d-d absorption energy and half-wave potential of complex ions at ACT was considered. Macrocyclic ligands increasing d-d transition energy caused half-wave potentials of Ni(II)-macrocycle to be shifted more positively. The half-wave potentials for Ni(rac-1[14]7-diene)$^{2+}$, Ni(meso-1[14]7-diene)$^{2+}$, Ni(1[14]4-diene)$^{2+}$, $\alpha$-Ni(rac-[14]-decane)$^{2+}$, ${\beta}-Ni(rac-[14]-decane)$^{2+}$, and Ni(meso-[14]-decane)$^{2+}$ reductions were -1.419, -1.431, -1.450, -1.473, and -1.480 (V vs. SCE), respectively. The d-d transition energies ($\nu_{max},\;cm^{-1}$) of the Ni(meso-[14]-decane)$^{2+}$ isomer were discussed with the dielectric constant (${\varepsilon}/{\varepsilon}_0$) of the various solvents, $\nu_{max}(cm^{-1})$ increased with increasing ${\varepsilon}/{\varepsilon}_0$.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.118-124
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• 2009

Esterase EM2L8 gene isolated from deep sea sediment was expressed in Escherichia coli BL21 (DE3) and the esterase activity of the cell-free extract was assayed using p-nitrophenyl butyrate-spectrophotometric method. Its optimum temperature was $40-45^{\circ}C$ and 45% activity of the maximum activity was retained at $15^{\circ}C$. The activation energy at $15-45^{\circ}C$ was calculated to be 4.9 kcal/mol showing that esterase EM2L8 was a typical cold-adapted enzyme. Enzyme activity was maintained for 6 h and 4 weeks at $30^{\circ}C$ and $4^{\circ}C$, respectively. When each ethanol, methanol, and acetone was added to the reaction mixture to 15% concentration, enzyme activity was maintained. In the case of DMSO, enzyme activity was kept up to 40% concentration. (S)-4-Chloro-3-hydroxy butyric acid is a chiral intermediate for the synthesis of Atorvastatin, a hyperlipemia drug. When esterase EM2L8 (40 U) was added to buffer solution (1.2 mL, pH 9.0) containing ethyl-(R,S)-4-chloro-3-hydroxybutyrate (38 mM), it was hydrolyzed into 4-chloro-3-hydroxy butyric acid with a rate of $6.8\;{\mu}mole/h$. The enzyme hydrolyzed (S)-substrate more rapidly than (R)-substrate. When conversion yield was 80%, e.e.s value was 40%. When DMSO was added, hydrolysis rate increased to $10.4\;{\mu}mole/h$. The plots of conversion yield vs e.e.s in the presence or absence of DMSO were almost same, implying that the reaction enantioselectivity was not changed by the addition of DMSO. Taken together, esterase EM2L8 had high activity and stability at low temperatures as well as in various organic solvents/aqueous solutions. These properties suggested that it could be used as a biocatalyst in the synthesis of useful pharmaceuticals.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.28-37
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• 2017

Mineral trioxide aggregate have been used for many years as a pulp therapy material. The most widely used product, Proroot white $MTA^{(R)}$ has a major drawback that it causes tooth discoloration. This study assessed discoloration of crown when various MTA-based materials were placed in the coronal aspect of the root canal. Seventy-five single-rooted, unrestored premolar teeth were selected. The teeth were randomly assigned to four experimental groups, each of $Biodentine^{(R)}$, Proroot $wMTA^{(R)}$, $Endocem^{(R)}$, $RetroMTA^{(R)}$ and one negative control groups. Color measurements were utilized by the Commission International de I'Eclairage's L*a*b* system with spectrophotometer. The color was assessed eight times : initial, 1 day, 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 16 weeks after the placement. Statistical analysis was performed using the 2-way repeated analysis of variance and Bonferroni's method with p < 0.05. Proroot $wMTA^{(R)}$ induced significant decreases in $L^*$ values during experiment period. Tooth samples from the $Endocem^{(R)}$ group presented indistinct grayish color changes. The $Biodentine^{(R)}$ and $RetroMTA^{(R)}$ showed color stability. Consequently, while Proroot $wMTA^{(R)}$ and $Endocem^{(R)}$ that contain bismuth oxide as a radiopacifier showed tooth discoloration, displayed no sign of discoloration $Biodentine^{(R)}$ and $RetroMTA^{(R)}$ that contain zirconium oxide as a radiopacifier.