• Restorative Dentistry and Endodontics
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• v.13 no.2
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• pp.221-235
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• 1988

The purpose of this study was to observe characteristic properties through the polarization curves and EMPA images from 4 different types of amalgam obtained by using the potentiostats (EG & G PARC) & EPMA (Jeol JSM-35), to investigate the degree of corrosion of each phase of amalgam on the oxidation peak, and to identify corrosion products from the corroded amalgam by use of X-ray diffractometer(Rigaku). After each amlgam alloy and Hg were triturated as the direction of the manufacturer by means of the mechanical amalgamator(Shofu), the triturated mass was inserted into the cylindrical metal mold which was 12mm in diameter and 10mm in height and was condensed by means of routine manner. The specimen was removed from the mold and stored at room temperature for about 7 days. The standard surface preparation was routinely carried out. Anodic polarization measurement was employed to compare the corrosion behaviours of the amalgams in 0.9% saline solution(pH6.8~7.0) and artificial saliva (pH6.8~7.0) at $37^{\circ}C$. The open circuit potential was determined after 30 minutes' immersion of specimen in electrolyte and the potential scan was begun at the potential of 100mV cathodic from the corrosion potential. The scan rate was 1mV/sec and the surface area of amalgam exposed to the solution was 0.64$cm^2$ for each specimen. All the potentials reported are with respect to a saturated calomel electrode (SCE). EPMA images on the determined oxidation peaks of each amalgam in artificial saliva were observed. X-ray diffraction patterns of each sample were recorded before and after polarization in artificial saliva (Aristaloy, Caulk Spherical, Dispersalloy and Tytin: at +770mV, +585mV, +8.10m V and +680m V respectively) by use of a recording diffractometer. Nickel filtered Cu $K_{{\alpha}_1}$ radiation was used and sample was scanned at $4^{\circ}(2{\theta})/min.$ from $25^{\circ}$ to $80^{\circ}$. The following results were obtained. 1. Oxidation peak potential in artificial saliva shifted to more anodic direction than that in saline solution. 2. The corrosion potential of high copper amalgam was more anodic than the potential of low copper amalgam. 3. The current density was lower in artificial saliva than in saline solution. 4. One of the corrosion products, AgCl was identified by X-ray diffraction analysis. 5. ${\gamma}_2$ phase was the most susceptible to corrosion and e phase was stable in low copper amalgam and ${\eta}$' phase and Ag-Cu eutectic were susceptible to corrosion in high copper amalgam.

• Journal of Ginseng Research
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• v.41 no.4
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• pp.540-547
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• 2017

Background: In general, after Panax ginseng is administered orally, intestinal microbes play a crucial role in its degradation and metabolization process. Studies on the metabolism of P. ginseng by microflora are important for obtaining a better understanding of their biological effects. Methods: In vitro biotransformation of P. ginseng extract by rat intestinal microflora was investigated at $37^{\circ}C$ for 24 h, and the simultaneous determination of the metabolites and metabolic profile of P. ginseng saponins by rat intestinal microflora was achieved using LC-MS/MS. Results: A total of seven ginsenosides were detected in the P. ginseng extract, including ginsenosides Rg1, Re, Rf, Rb1, Rc, Rb2, and Rd. In the transformed P. ginseng samples, considerable amounts of deglycosylated metabolite compound K and Rh1 were detected. In addition, minimal amounts of deglycosylated metabolites (ginsenosides Rg2, F1, F2, Rg3, and protopanaxatriol-type ginsenosides) and untransformed ginsenosides Re, Rg1, and Rd were detected at 24 h. The results indicated that the primary metabolites are compound K and Rh1, and the protopanaxadiol-type ginsenosides were more easily metabolized than protopanaxatriol-type ginsenosides. Conclusion: This is the first report of the identification and quantification of the metabolism and metabolic profile of P. ginseng extract in rat intestinal microflora using LC-MS/MS. The current study provided new insights for studying the metabolism and active metabolites of P. ginseng.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.6
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• pp.853-859
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• 2007

This study investigated the quality characteristics of bread made with different additions of Chungkukjang powder (0, 10, 20%). In the microbiological evaluations, total aerobic bacteria increased with increases in Chungkukjang powder concentration and storage period ($20^{\circ}C$, 3 days). The pH also increased with increasing Chungkukjang powder concentration. For the color values, with increasing Chungkukjang powder content, the lightness (p<0.05) decreased in both the bread crumb and crust, while redness (p<0.05) increased. The yellowness decreased for the bread crust and increased for the bread crumb. Hardness and chewiness were higher, but springiness and cohesiveness were lower, in the breads made with 10 or 20% Chungkukjang powder as compared to the control. The control bread obtained the highest sensory scores for texture and overall acceptability during the storage period. Optimum sensory scores for color, texture, and overall acceptability were obtained for the bread with 10 % Chungkukjang powder until day 1 of storage. From the results of this study, 10% Chungkukjang powder can be added to bread without diminishing its acceptability, but further study is necessary on extending shelf-life and improving consumer acceptance.

• Tuberculosis and Respiratory Diseases
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• v.38 no.1
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• pp.8-15
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• 1991

It has been well known that the integrity of airway epithelium is important in development of bronchial hyperreactivity and bronchial asthma. But the mechanisms involved are still unclear. To evaluate that airway epithelium is able to modulate the contraction of guinea pig tracheal smooth muscle, we investigated the responsiveness of intact and epithelium-denuded tracheal strips to histamine and acetylcholine. And to evaluate whether cyclooxgenase products play a role in this modulatory mechanism, we also investigated the effect of indomethacin pretreatment on the tracheal responsiveness to histamine. Results were as follows: 1) In guinea pig tracheal smooth muscle the presence of airway epithelium significantly reduced the response to histamine. 2) In the presence of indomethacin dose-response curves and $EC_{50}$ values were similar between intact and epithelium-denuded tracheal strips, that is, indomethacin abolished the influence of epithelium on the contracion of tracheal smooth muscle. 3) The response of tracheal smooth muscle to acetylcholine was similar both in the presence and absence of epithelium. These results suggest that airway epithelium of guinea pig may generate an inhibitory signal to decrease the response of tracheal smooth muscle to histamine and cyclooxygenase products may contrbute to the modulation of airway epithelium on the contracion of tracheal smooth muscle.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.3
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• pp.355-359
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• 1997

Leiomyomas, which are the commonest pelvic tumors in women, are originated from myometrial cells. Although the exact initial pathophysiologic event of the leiomyoma is not known, recent evidences suggested that the effects of sex steroid hormones in the process of tumor growth are mediated by local production of growth factors including epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I) and insulin-like growth factor-II (IGF-II). If we look at the effects of other cytokines, it was suggested that basic fibroblast growth factor (bFGF) may stimulate the proliferation of myometrial and leiomyomas cells. And it was reported that interferon-${\alpha}$ inhibit the action of bFGF. Therefore, we examined the effect of bFGF and interferon-${\alpha}$ on the proliferation of leiomyoma and myometrial cells. bFGF stimulated the myometrial and leiomyoma cells significantly at the concentration of 1ng/ml (p<0.05) and 5ng/ml (p<0.05). However, Interferon-${\alpha}$ inhibited the cell proliferation of myometrial and leiomyoma cells significantly at the concentration of 100U/ml (p<0.05) and 1000U/ml (p<0.05). And the stimulated effects of bFGF with the various concentration on the myometrial and leiomyoma cells ware inhibited by interferon-${\alpha}$ with 100U/ml. Therefore, we concluded that bFGF may stimulate the myometrial and leiomyoma cell proliferation and interferon-${\alpha}$ may inhibit the myometrial and leiomyoma cell proliferation through blocking the effect of basic fibroblast growth factor.

• Journal of Astronomy and Space Sciences
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• v.19 no.4
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• pp.305-318
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• 2002

We have constructed two flight models of airglow photometer system (AGP) to be onboard Korea Sounding Rocket-III (KSR-III) for detection of MUV dayglow above the Korean peninsular. The AGP system is designed to detect dayglow emissions of OI 2972${\AA}$, $N_2$ VK(0,6) 2780${\AA}$, $N_2$ 2PG 3150${\AA}$ and background 3070${\AA}$ toward the horizon at altitudes between 100 km and 300 km. The AGP system consists of a photometer body, a baffle an electronic control unit and a battery unit. The MUV dayglow emissions enter through a narrow band interference filter and focusing lens of the photometer, which contains an ultraviolet sensitive photomultiplier tube. The photometer is equipped with an in-flight calibration light source on a circular plane that will rotate at the rocket's apogee. A bane tube is installed at the entry of the photometer in order to block strong scattering lights from the lower atmosphere. We have carried out laboratory measurements of sensitivity and in-flight calibration light source for the AGP flight models. Although absolute sensitivities of the AGP flight models could not be determined in the country, relative sensitivities among channels are well measured so that observation data during rocket flight in the future can be analyzed with confidence.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.131-140
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• 1995

This experiment was conducted to test the effect on germination and seedling growth of major industrial crops and weed control potential using alfalfa plant. When dried alfalfa residues were mixed into vermiculite, germination, length of shoot and root of crops, such as Perilla frutescens, Sorghum nevosum, Platycodon grandiflorum and weeds, Digitaria saguinalis, Setaria viridis, Siegesbechia pubescens, Ammaranthus lividus, and Solanum nigrum, were significantly inhibited as the dried residue concentration increased. More than 10% concentration of the dired residue caused 80% germination and growth inhibition. The fresh alfalfa exudation also inhibited the germination and seedling growth of crop, barley, rye, alfalfa, and sesame, and weeds, Echinochloa crus-galli, Siegesbechia viridis, and Portulaca oleracea. The degree of inhibition showed the different response according to the fresh exudation concentration, types of crops and weeds. Generally, as the exudation concentration increased, the germination and seedling growth of crops and weeds inhibited. The exudation of dried residue also exhibited the strong inhibition effect on germination and seedling growth of crops, alfalfa, Platycodon grandiflorum, barley, sesame, rye and weeds, D. sanguinalis, S. pubescens, S. viridis, P. oleracea, E. crus-galli, At the 10% concentrations, S. pubescens, and P. oleracea were not germinated and showed only 15% germination in the S. viridis. From this study, would conclude that alfalfa plant contained water soluble phytotoxic substances which were inhibitory to weeds and crops. This results suggest that alfalfa had some possibility to control some weed species using toxic compounds like natural herbicide.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.148-153
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• 1995

Glyphosate (N-[phosphonomethyl]glycine) applied to the assimilate-exporting leaves or sprayed to the whole plants of tomato(Lycopersicon esculentum Mil var. Moneymaker) induced the rapid inhibition of 5-enolpyruvyl skimic acid 3-phosphate synthase(EPSP-synthase). It shows that EPSP-synthase activity precedes chlorophyll loss. There is no difference in EPSP-synthase activity between in vivo tomato meristem and cell suspension culture if glyphosate is not applied. The EPSP-synthase activity is in a range of 4 to 6 nkat per mg protein. The inhibition of EPSP-synthase action is induced within 36 h after glyphosate application while the Chl contents were reduced 48 h after the application. In cell suspension culture of tomato and Corydalis (Corydalis sempervirens), a sublethal concentration of glyphosate retards the fresh weight increase and prolonged lag phase. The fresh weight is reached maximal about 14 days after the subculture in the presence of glyphosate. The inhibitory effect of glyphosate on EPSP-synthase is remarkably induced in lag phase.

• Journal of Plant Biotechnology
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• v.41 no.4
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• pp.194-200
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• 2014

Monodehydroascorbate reductase (MDHAR) is an important enzyme that plays a role in the detoxification of reactive oxygen species (ROS) by maintaining reduced pool of ascorbate through recycling the oxidized form of ascorbate. In this study, we isolated a PagMDHAR1 gene from Populus alba ${\times}$ P. glandulosa, and investigated its expression characteristics. The PagMDHAR1 cDNA encodes a putative 434 amino acids containing FAD- and NAD(P)H-binding domains. Southern blot analysis indicated that a single nuclear gene encodes this enzyme. Northern hybridization analysis revealed that PagMDHAR1 is highly expressed in both suspension cells and flower tissues, while its expression levels were enhanced by drought, salt, cold, wounding and ABA. Therefore, PagMDHAR1 might be expressed in response to abiotic stress through the ABA-mediated signaling pathway in this poplar species, suggesting that the PagMDHAR1 plays an important role in the defense mechanisms against oxidative stress.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.20 no.4
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• pp.227-235
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• 2017

Purpose: Crohn's disease (CD) can involve any site of the gastrointestinal tract (GIT). However, the characteristics of upper GIT involvement in CD are unclear, especially in the Eastern pediatric population. This study aimed to estimate the prevalence of upper GIT involvement and identify the clinical features of Korean children with CD. Methods: This was a retrospective multicenter cohort study that included 52 pediatric patients with CD who underwent esophagogastroduodenoscopy and biopsy. The clinical symptoms and endoscopic and histologic features of the upper GIT were identified according to the presence or absence of upper gastrointestinal symptoms. Results: Among the 52 patients, upper GIT involvement was noted in 50.0% (26/52). The mean age at CD diagnosis was $14.1{\pm}2.1$ years. Gastric ulcer was the most common lesion (19.2%) found on upper GIT endoscopy, followed by duodenal ulcers (15.4%). Chronic inflammation was the most common histopathologic feature (75.0%), followed by gastric erosion (17.3%). Granuloma was found in 9.6% of patients. Helicobacter pylori infection was identified in 5.8% of patients. Endoscopic and histologic findings were not significantly different, but the mean values of erythrocyte sedimentation rate ($60.7{\pm}27.1$ vs. $43.0{\pm}27.6mm/h$, p=0.037) and C-reactive protein ($16.5{\pm}28.2$ vs. $6.62{\pm}13.4mg/dL$, p=0.014) were significantly different between patients with and without upper gastrointestinal CD symptoms. Conclusion: Upper GIT involvement was relatively common in pediatric patients with CD irrespective of upper gastrointestinal symptoms, and H. pylori infection was relatively uncommon. The results of this study should aid the establishment of regional guidelines for upper GIT examination.