• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.560-574
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• 1997

The present study was undertaken to investigate the crystal growth onto human enamel mineral and synthetic hydroxyapatite(HA) seeds in media resembling the enamel fluid composition. Effects of fluoride at high concentrations on the precipitation were also examined in a bench-top crystal growth model adopting a miniaturized reaction column. The Ca, P and F concentrations and pH values of the inlet and outlet solutions were determined. The recovered solid samples were weighed to assess the amount of minerals precipitated during the experimental period, and finally viewed under a scanning electron microscope. Remarkable findings were that 1) both biological and synthetic seeds with the same total surface areas yielded similar amounts of crystal growth, 2) the amount of crystal growth was accelerated in a manner depending on fluoride concentrations in the media, 3) SEM observations disclosed that without the addition of fluoride, precipitation of thin, plate-like OCP crystals became prominent, but by increasing the fluoride concentration(beyond 1ppm F), rod-like crystals having a pointed edge were most frequently observed, without any evidence for precipitation of the plate-like crystals. Furthermore, the dimension of rod-like crystals was increased in proportion to fluoride concentrations, 4) there was no difference in the morphological feature of precipitated mineral phase upon seeding between human enamel seed and synthetic HA seed. The overall results support the view that the seeded crystal growth model is of value to gain insight into the mechanism of enamel crystal growth under fluoride regimens.

• Mycobiology
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• v.39 no.2
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• pp.103-108
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• 2011

Amylases and cellulases are important enzymes that can be utilized for various biological activities. Ten different wild Nigerian mushrooms (Agaricus blazei, Agaricus sp., Corilopsis occidentalis, Coriolus versicolor, Termitomyces clypeatus, Termitomyces globulus, Pleurotus tuber-regium, Podoscypha bolleana, Pogonomyces hydnoides, and Nothopanus hygrophanus) were assayed for production of these secondary metabolites. The results revealed that most of the tested wild fungi demonstrated very good amylase and cellulase activities. With the incorporation of carboxymethyl-cellulose (a carbon source) into the culture medium, Agaricus blazei had the highest amylolytic activity of 0.60 unit/mL (at $25^{\circ}C$, pH 6.8). This was followed in order by P. tuber-regium and Agaricus sp. with 0.42 and 0.39 unit/mL, respectively ($p {\leq} 0.05$). Maltose and sucrose supplementation into the submerged liquid medium made N. hygrophanus and P. hydnoides to exhibit very low amylase activities of 0.09 and 0.11 unit/mL, respectively. Introducing peptone (an organic nitrogen source) into the basal medium enhanced the ability of C. versicolor to produce a cellulase value of 0.74 unit/mL. Other organic nitrogen sources that supported good cellulase activities were yeast extract and urea. Sodium nitrate (inorganic nitrogen source) generally inhibited cellulase production in all mushrooms. The best carbon source was carboxymethyl-cellulose, which promoted very high cellulase activity of 0.67 unit/mL in C. versicolor, which was followed in order by P. tuber-regium, T. chypeatus, and C. occidentalis ($p {\leq} 0.05$). Sucrose was the poorest carbon compound, supporting the lowest values of 0.01, 0.01, and 0.14 unit/mL in P. hydnoides, A. blazei, and Agaricus sp., respectively.

• The Korean Journal of Mycology
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• v.43 no.2
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• pp.92-98
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• 2015

Hydrocharis dubia Backer and Salvinia natans All. were sampled from the Junam and Dongpan reservoirs, representative freshwater wetlands of Korea. A total of 19 endophytic fungal strains were isolated from hydrophytes native to the Junam wetlands and 5 strains were isolated from the Dongpan wetlands. Depending on phylogenetic analysis based on internal transcribed spacer (ITS) region, strains from Junam belonged to 11 genera and from Dongpan belonged to 5 genera. Fusarium, Phoma and Talaromyces were commonly distributed genera from two wetlands. The fungal diversity index showed clear differences between each wetlands or each host hydrophyte. Above all, the highest diversity value was observed from Salvinia natans All., which have been reported as promising biological resources as eutrophication controller in environmental ecology.

• Korean Journal of Medicinal Crop Science
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• v.23 no.1
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• pp.37-42
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• 2015

This study was to investigate anti-skin wrinkle effect of Agastache rugosa Kentz extracts by extraction processes. In the comparison of the effect of the solvent extraction, the extracts by 70% ethanol (EE) showed better biological activities that those by hot water. Therefore, further fermented Agastache rugosa was applied to 70% ethanol extraction process (FEE). FEE showed higher DPPH scavenging activity of 62.98% than EE's 62.71% at $1.0mg/m{\ell}$, but there was no significant. Elastase inhibition was measured 23.0% from FEE at $1.0mg/m{\ell}$. Cytotoxicity showed the highest 16.26% from FEE, this value is safe in the cell experiment. Collagen production showed $113.1ng/m{\ell}$ from FEE, on the other hand EE was measured $77.4ng/m{\ell}$ in adding $1.0mg/m{\ell}$. MMP-1 production was observed $1398pg/m{\ell}$ from FEE and EE was measured $1632pg/m{\ell}$. These results were found the highest antioxidant and anti-wrinkle effect. As a result, it was also confirmed that anti-skin wrinkle activities of the Agastache rugosa Kentz extract was correlated with anti-oxidant activities.

• Korean Journal of Medicinal Crop Science
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• v.24 no.3
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• pp.222-227
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• 2016

Background: The biological activities of Tradescantia pallida grown in Korea have not been well determined, thus the aim of this study was to investigate the possibility of using it as a medicinal plant. Methods and Results: To investigate the antioxidant activity, ${\alpha}$-glucosidase inhibitory effect and antimicrobial activity of T. pallida, we performed the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and reducing power assay. This assay for T. pallida leaf extract showed the highest antioxidant activity for the ethyl acetate fraction ($RC_{50}=14.55{\pm}0.16{\mu}g/m{\ell}$ and Abs = 0.613 at $300{\mu}g$). Further, the ethyl acetate fraction exhibited higher ${\alpha}$-glucosidase inhibitory effect with an $IC_{50}$ value of $14.1{\pm}0.1{\mu}g/m{\ell}$ and showed antimicrobial activity against gram positive bacteria (minimum inhibitory concentration = $1,000{\mu}g/m{\ell}$). Conclusions: The ethyl acetate fraction of the crude methanol extract of T. pallida showed remarkable antioxidant activity, ${\alpha}$-glucosidase inhibitory effects and antimicrobial activity. These activities might be related to the flavonoid content in the T. pallida leaf extract.

• The Journal of Korean Medicine
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• v.20 no.3 s.39
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• pp.105-114
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• 1999

To investigate the anti-complementary and cytotoxic effects of oriental prescription, Kuseonwangdogo, on the proliferation of preadipocyte 3T3- L1 cells, we examined biological effects of Kuseonwangdogo. The results obtained were as follows. 1. After 14 days, the body weight of rats treated with Kuseonwangdogo decreased more than that in the control group (p<0.05). However, the weights of liver, spleen and kidney were unchanged. In serum biochemical test, we examined the level of glucose (GLU) and glutamic pyruvic transaminase (GPT). The levels of GOT and CHOL in serum were decreased remarkably by the administration of Kuseonwangdogo (p<0.05). The haematological examination of the tested group showed significant increment of white blood cells (WBC), hemoglobin concentration (HGB), mean corpuscular hemoglobin (MCH) and monocyte (MO). 2. The effect of Kuseonwangdogo on the proliferation of 3T3-L1 cells was tested by the sulforhodamin B(SRB) assay. The high concentration ($100{\mu}l\;and\;200{\mu}l$) of extracts inhibited the proliferation of 3T3- L1 cells. The p-value was <0.01, respectively. 3. The extract of Kuseonwangdogo showed a potent anti -complementary activity. It was suggested that the active principle may be a kind of polysaccharide molecule. 4. The cytotoxic effects of Kuseonwang dogo and its composing herbs in human liver cells (WRL68) and monkey kidney cells (Vero) were examined by the SRB and 3- (4,5- Dimethylthiazol-2-yl) -2,5 diphenyl-2H- tetrazolium bromide (MTT) assay. Cytotoxic effects were not observed.

• Ocean and Polar Research
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• v.29 no.4
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• pp.339-348
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• 2007

In this work, we compared the characteristics of three benthic biotic indices (BPI, AMBI, BIBI) which indicates the health condition of benthic communities in Masan Bay, Korea where anthropogenic impacts have been concentrated. Also we evaluated the usefulness of these benthic indices and some problems if they were applied to the Korean coastal waters. For this we used the macrozoobenthos data collected using van Veen grab ($0.1\;m^2$) at 21 sites in Masan Bay in February and August 2004. Based on the BPI values, two stations in the inner bay were found in a very hard polluted condition and three stations in the middle bay were also in a highly polluted condition. Only one station located in the bay mouth was in a normal condition. The inner bay stations showed very high AMBI values (${\geq}5.0$), indicating a highly polluted condition. The bay mouth station was assessed in a moderately polluted condition. The overall BIBI values in Masan Bay were in the range between 1.0 and 3.0. The inner bay stations showed low BIBI values (${\leq}2.0$) in the severely degraded condition. The bay mouth station with high BIBI value over 3.0 was assessed as a normal condition. All three benthos indices showed that macrozoobenthic communities in the inner bay were in a seriously polluted condition all year round, and macrobenthic faunas in the bay mouth seemed in a bad healthy condition (slightly polluted) based on AMBI during summer season. These three benthic biotic indices showed the similar assessment result, and thus we consider that each of them is a useful tool for the assessment of coastal benthic ecosystems under the organic enrichment in sediment.

• Journal of Biomedical Engineering Research
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• v.18 no.1
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• pp.25-36
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• 1997

To regulate cardiac output of the Total Artificial Heart(TAH) physiologically, the hemodynamic information must be toed back to the controller. So far, our group has developed an automatic cardiac output control algorithm using the motor current waveform, It is, however difficult to detect the preload level such as a filling status of ventricular inflow and the variation of atrial pressures within normal physiologic range(0-15 mmHg) by analyzing the motor current which simultaneously reflects the afterload effect. On the other hin4 the interventricular volume pressure(IVP) which is not influenced by arterload but by preload is a good information source for the estimation of preload states. In order to find the relationship between preload and IVP waveform, we set up the artificial heart system on the Donovan type mock circulatory system and measured the IVP waveform, right and left atrial pressures, inflow and outflow waveforms and the signals represented the information of moving actuator's position. We shows the feasibility of estimating the hemodynamic changes of inflow by using IVP waveform. fife found that the negative peak value of IVP waveform is linearly related to atrial pressures. And we also found that we could use the time to reach the negative peak in IVP waveform, the time to open outflow valve, the area enclosed IVP waveform as unfu parameters to estimate blood filling volume of diastole ventricle. The suggested method has advantages of avoiding thrombogenesis, bacterial niche formation and increasing longterm reliability of sensor by avoiding direct contact to blood.

• Journal of Biomedical Engineering Research
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• v.20 no.3
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• pp.299-305
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• 1999

In thls paper, the representative beal textraction algorIthms for the diagnostic parameter extraction in noisy signal were compared. We used the avernge, median, mode, and trmmed mean to calculale the central tendency. In our experimenl, we have restricted to four kinds of noises -EMG noise, 60Hz powerline inlerference, ahrupl baseline shift, and baselme drift due to respimtion-which were commonly occurred in ECG mgnal, then we have calculated signal-to-noise ratios(SNRs) for the ECG corrupted with each noise and all noises together. As the result of this paper, we have proved that the average method has super lor performance than the others in the ECG corrupted wilh EMG noise. When the signal mcludes extreme value such as abrupt baseline shIft, the median, mode, trimmed mean methods have supenor performance in the SNR ratios. Especially when the ECG corrupted with baseline drift due to respirallon, the trimmed mean method was most efficient because ST level change was 0 V.

• Journal of Biomedical Engineering Research
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• v.37 no.3
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• pp.105-111
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• 2016

Introduction: Surgical robot is the alternative instrument that substitutes the difficult and precise surgical operation; should have intuitiveness operationally to transfer natural motions. There are limitations of hand motion derived from contacting mechanical handle in the surgical robot master interface such as mechanical singularity, isotropy, coupling problems. In this paper, we will confirm and verify the feasibility of intuitive Non-restraint master interface which tracking the hand motion using infra-red camera and only 3 reflective markers without the hardware handle for the surgical robot master interface. Materials & methods: We configured S/W and H/W system; arranged 6 infra-red cameras and attached 3 reflective markers on hands for measuring 3 dimensional coordinate then we find the 7 motions of grasp, yaw, pitch, roll, px, py, pz. And we connected Virtual-Master to the slave surgical robot(Laparobot) and observed the feasibility. To verify the result of motion, we compare the result of Non-restraint master and that of clinometer (and protractor) through measuring 0~180 degree, 10degree interval, 1000 samples and recorded standard deviation stands for error rate of the value. Results: We confirmed that the average angle values of Non-restraint master interface is accurately corresponds to the result of clinometer (and protractor) and have low error rates during motion. Investigation & Conclusion: In this paper, we confirmed the feasibility and accuracy of 3D Non-restraint master interface that can offer the intuitive motion of non-contact hardware handle. As a result, we can expect the high intuitiveness, dexterousness of surgical robot.