• Journal of Veterinary Clinics
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• v.23 no.1
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• pp.55-60
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• 2006

Aucuba japonica has variable pharmacological effects such as hepatoprotective, choleretic, hemodynamic, antimicrobial, and anti-inflammatory activities. This study was performed to investigate the effects of Aucuba japonica extract on oral wound healing. Aucubin was extracted from Aucuba japonica, and injected on either side of buccal mucosa of male mice. Artificial full thickness wounds were made on the site with 1.5 mm biopsy punch under sterile technique. The specimens had taken on day 1, 3, and 5 with 4 mm biopsy punch. Light microscopic examination and quantitative histologic analysis were performed for reepithelization, inflammatory cell infiltration. Reepithelization of the aucubin (0.1%) group was earlier than the control group. And the number of inflammatory cells of the aucubin group was lesser than the control group. In view of the results so far achieved, the aucubin extracted from Aucuba japonica may be useful for oral wound healing and it can be applied as a topical agent on the oral wound. Further research should be performed on the mechanism of aucubin on oral wound healing and proper formulation for effective topical agents.

• Journal of Welding and Joining
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• v.26 no.4
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• pp.85-91
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• 2008

The grooving corrosion is caused mainly by the different microstructures between the matrix and weld which is formed during the rapid heating and cooling cycle in welding. By this localized corrosion reaction of pipes, it evolves economic problems such as the early damage of industrial facilities and pipe lines of apartment, and water pollution. So lots of researches were carried out already about grooving corrosion mechanism of ERW carbon steel pipe but there is seldom study for water hammer happened by fluid phenomenon and corrosion rate by flow velocity. In this study, the analysis based on hydrodynamic and fracture mechanics was carried out. ANSYS, FLUENT and STAR-CD were used for confirmation of flow phenomenon and stress on the pipe. As the results, fatigue failure is able to be happened by water hammer and grooving corrosion rate is increased cause by turbulent. Grooving corrosion is happened on the pipe, then friction loss of fluid is occurred from corroded part. Erosion can be happened enough in corroded region of microscopic size that wear "V" form. Also pipe is able to be damaged by water hammer effects because of corroded region is general acting as a notch effects. Corrosion depth was more than half of total thickness, it can be damaged from water hammer pressure.

• Journal of Microbiology and Biotechnology
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• v.28 no.6
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• pp.917-930
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• 2018

Intracellular synthesis of silver/silver chloride nanoparticles (Ag/AgCl-NPs) using Meyerozyma guilliermondii KX008616 is reported under aerobic and anaerobic conditions for the first time. The biogenic synthesis of Ag-NP types has been proposed as an easy and cost-effective alternative for various biomedical applications. The interaction of nanoparticles with ethanol production was mentioned. The purified biogenic Ag/AgCl-nanoparticles were characterized by different spectroscopic and microscopic approaches. The purified nanoparticles exhibited a surface plasmon resonance band at 419 and 415 nm, confirming the formation of Ag/AgCl-NPs under aerobic and anaerobic conditions, respectively. The planes of the cubic crystalline phase of the Ag/AgCl-NPs were confirmed by X-ray diffraction. Fourier-transform infrared spectra showed the interactions between the yeast cell constituents and silver ions to form the biogenic Ag/AgCl-NPs. The intracellular Ag/AgCl-NPs synthesized under aerobic condition were homogenous and spherical in shape, with an approximate particle size of 2.5-30nm as denoted by the transmission electron microscopy (TEM). The reaction mixture was optimized by varying reaction parameters, including temperature and pH. Analysis of ultrathin sections of yeast cells by TEM indicated that the biogenic nanoparticles were formed as clusters, known as nanoaggregates, in the cytoplasm or in the inner and outer regions of the cell wall. The study recommends using the biomass of yeast that is used in industrial or fermentation purposes to produce Ag/AgCl-NPs as associated by-products to maximize benefit and to reduce the production cost.

• Environmental Analysis Health and Toxicology
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• v.21 no.1 s.52
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• pp.71-79
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• 2006

Epidemiologic studies have showed a close correlation between arsenic exposure and heart disease such as, cardiovascular problem, ischemic heart disease, infarction, atherosclerosis and hypertension in human. It may increase the mortality of high risk group with heart disease. Regarding the mechanism studies of heart failure, blood vessel, vascular smooth muscle cells and endothelial cells have long been focused as the primary targets in arsenic exposure but there are only a few studies on the cardiomyocytes. In this study, the generation of oxidative stress by low dose of arsenic trioxide was investigated in rat cardiomyocytes. By direct measurement of reactive oxygen species and fluorescent microscopic observation using fluorescent dye 2',7'-dichlorofluorescin diacetate, reactive oxygen species were found to be generated without cell death, where cells are treated with 0.1 ppm arsenic for 24 hours. With the induction of reactive oxygen species, GSH level was decreased by the same treatment. However, DNA damage did not seem to be serious by DAPI staining, while high dose of arsenic (2 ppm for 24 hrs) caused fragmentation of DNA. To identify the molecular biomarkers of low-dose arsenic exposure, gene expression was also investigated with whole genome microarray. As results, 9,022 genes were up-regulated including heme oxygenase-l and glutathione S-transrerase, which are well-known biomarkers of oxidative stress. 9,404 genes were down-regulated including endothelial type gp 91-phox gene by the treatment of 0.1 ppm arsenic for 24 hours. This means that biological responses of cardiomyocytes may be altered by ROS induced by low level arsenic without cell death, and this alteration may be detected clearly by molecular biomarkers such as heme oxygenase-1.

• Restorative Dentistry and Endodontics
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• v.27 no.3
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• pp.257-269
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• 2002

Objective : The purpose of this study was to evaluate the resin infiltration into dentin of one-bottle adhesive systems and self-etching primer bonded to Class V cavities using confocal laser scanning microscope(CLSM). Material and Methods : Forty Class V cavities were prepared from freshly extracted caries-free Human teeth. These teeth were divided into two groups based on the presence of cervical abrasion: Group I, cervical abrasion : Group II, wedge-shaped cavity preparation. Resin-dentin interfaces were produced with two one-bottle dentin bonding systems-ONE COAT BOND(OCB; Coltene$^R$) and Syntac$^R$SPrint$^{TM}$(SS; VIVADENT)-, one self-etching priming system-CLEARFIL$^{TM}$ SE BOND (SB : KURARAY)- and one multi-step dentin bonding system-Scotchbond$^{TM}$Multi-Purpose (SBMP, 3M Dental Products)-as control according to manufacturers' instructions. Cavities were restored with Spectrum$^{R}$(Dentsply). Specimens were immersed in saline for 24 hours and sectioned longitudinally with a low-speed diamond disc. The resin-dentin interfaces were microscopically observed using CLSM. The quality of resin-infiltrated dentin layers were evaluated by five dentists using 0~4 scale. Results : Confocal laser scanning microscopal investigations using primer labeled with rhodamine B showed that the penetration of the primer occurred along the cavity margins. Statistical analysis using one-way ANOVA followed by Duncan's Multiple Range test revealed that the primer penetration of the group 2(wedge-shaped cavity preparation) was more effective than group 1(cervical abrasion) and that of the gingival interfaces was more effective than the occlusal interfaces. In the one-bottle dentin bonding systems, the resin penetration score of OCB was compatible to SBMP, but those of SS and self-etching priming system, SB were lower than SBMP.

• Journal of Ginseng Research
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• v.36 no.2
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• pp.211-217
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• 2012

Endophytic fungi were isolated from various tissues (root, stem, petiole, leaf, and flower stalk) of 3- and 4-year-old ginseng plants (Panax ginseng Meyer) cultivated in Korea. The isolated endophytic fungi were identified based on the sequence analysis of the internal transcribed spacer (ITS), 1-5.8-ITS 2. A morphological characterization was also conducted using microscopic observations. According to the identification, 127 fungal isolates were assigned to 27 taxa. The genera of Phoma, Alternaria and Colletotrichum were the most frequent isolates, followed by Fusarium, Entrophospora and Xylaria. Although 19 of the 27 taxa were identified at the species level, the remainder were classified at the genus level (6 isolates), phylum level (Ascomycota, 1 isolate), and unknown fungal species (1 isolate). Endophytic fungi of 13 and 19 species were isolated from 3- and 4-year-old ginseng plants, respectively, and Phoma radicina and Fusarium solani were the most frequently isolated species colonizing the tissues of the 3- and 4-year-old ginseng plants, respectively. The colonization frequency (CF%) was dependant on the age and tissue examined: the CFs of the roots and stems in the 3-year-old ginseng were higher than the CF of tissues in the 4-year-old plants. In contrast, higher CFs were observed in the leaves and petioles of 4-year-old plants, and endophytic fungi in the flower stalks were only detected in the 4-year-old plants. In conclusion, we detected diverse endophytic fungi in ginseng plants, which were distributed differently depending on the age and tissue examined.

• Journal of Environmental Science International
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• v.6 no.3
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• pp.249-258
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• 1997

Mercury- and cadmium-resistant bacteria were Isolated from an Industrial complex wastewater of Taejon area. All of them were motile, gram negative rods. In the results of physicochemical test and VITEK card test. HM1 was Identified with Achetobacter cd- coaceucus, CM3 was Identified 65 Commonas acidovorns, HM2, HM3, CMI , and CM4 were Pseudomonas sp., but HM4 and CM2 were unidenteed. They were tested for subceptlbility to 14 heavy metals. Mercury-resistant bacteria(HM1, HM2, HM3, and HM4) were sensitive to low concentration(100~400ppm) of $Cd^{2+}$, $Co^{2+}$. $Zn^{2+}$, and Ni2+, while cadmium-resistant bacteria(CM1, CM2, CM3, and CM4) showed resistance up to the high concentration(600~ 1, 200ppm) of these metal loons. As a result of resistance spectrum test of mercury-resistant bacteria, HM1 was broad-spectrum strain, HM2. HM3, and HM4 were narrow-spectrum stratas. Transmission electron microscopic examination of cell wall of HM1 culture grown with and without 100ppm of $HgCl_2$ showed remarkably merphological abnormalities. In the result of atomic absorption spectrometric analysis of cadmium-resistant bacteria grown at 200ppm of $CdCl_2$ for 6h, all of them accumulated cadrnium(14ppm~57ppm) In cell. In cadinium-resistant bacteria, CM1, CM2, and CM4 were spared from the Inhibitory effect of $Cd^{2+}$ by the addition of $Mn^{2+}$, CM4 were also spared from the Inhibitory effect of $Cd^{2+}$ by the addition of $Mn^{2+}$ as well as $Zn^{2+}$.

• Journal of Electrochemical Science and Technology
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• v.2 no.4
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• pp.187-192
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• 2011

Photoelectrochemical performances of ZnO electrodes are enhanced by coupling with cobalt-based catalyst (CoPi) in phosphate electrolyte (pH 7). For this study, hexagonal pillar-shaped ZnO nanorods are grown on ZnO electrodes through a chemical bath deposition, onto which CoPi is deposited with different photodeposition times (10-30 min). A scanning electron microscopic study indicates that CoPi deposition does not induce any change of ZnO morphology and an energy-dispersive X-ray spectroscopic analysis shows that inorganic phosphate ions (Pi) exist on ZnO surface. Bare ZnO electrodes generate the current of ca. $0.36mA/cm^2$ at a bias potential of 0.5 V vs. SCE, whereas ZnO/CoPi (deposited for 10 min) has ca. 50%-enhanced current ($0.54mW/cm^2$) under irradiation of AM 1.5G-light ($400mW/cm^2$). The excess loading of CoPi on ZnO results in decrease of photocurrents as compared to bare ZnO likely due to limited electrolyte access to ZnO and/or CoPi-mediated recombination of photogenerated charge carriers. The primary role of CoPi is speculated to trap the photogenerated holes and thereby oxidize water into molecular oxygen via an intervalency cycle among Co(II), Co(III), and Co(IV).

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.1
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• pp.48-74
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• 1995

Since heat curing acrylic resins undergo unavoidable dimensional changes following polymerization, adaptation can be altered. Until recently, although numerous studies on the dimensional changes of denture base were based on a microscopic technic that measures the relative displacement of a limited reference points on the denture base, but there have been few studies on the distortions of resins using holographic interferometry. Purpose of this study was to determine and compare the dimensional changes and fringe patterns of 4 heat curing acrylic resins, and observe the distortions of acrylic resin denture base by temperature change with the aid of the holographic interferometry. Holographic interferograms were taken on the resin specimens and acrylic resin denture base with the 10mW He-Ne laser and double exposure method. Comparison and analysis of fringe pattern on the recorded object surface was performed. The following results were obtained. 1. The dimensional changes for the high impact resin Lucitone 199 were statistically the greatest of all resins, and the rapid heat curing resin Premium super 20 were the least. 2. The most polymerization shrinkage of all materials occured in initial period of measurements, at this time the difference of polymerization shrinkage properties between resins was founded. 3. The stress distribution of specimens was seen by various type of fringe pattern which had directionality. 4. The polymerization shrinkage of resins was greatly influenced by temperature change. 5. The partial deformations of resin denture base were observed in 70 C and 90 C water.

• Journal of Periodontal and Implant Science
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• v.40 no.2
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• pp.49-55
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• 2010

Purpose: The purpose of this study was to preliminarily evaluate the influence of diabetes mellitus (DM) on periodontal tissue without establishment of periodontitis. Methods: Seven-week-old db/db mice were used for the diabetic experimental group and systematically healthy mice of the same age were used as controls. After 1 week of acclimatization, the animals were sacrificed for hard and soft tissue evaluation. The pattern of bone destruction was evaluated by stereomicroscope evaluation with alizarin red staining and radiographic evaluation by microscopic computerized tomography images. Histological evaluation was performed with hematoxylin and eosin stain for evaluation of soft tissue changes. Results: In both stereomicroscope evaluation and radiograph image analysis, aggressive form of bone destruction was observed in diabetic animals when compared to the systematically healthy controls. In histological evaluation, apical migration of junctional epithelium with slight inflammatory cell infiltration was observed with disarrangement of connective tissue fibers. Conclusions: Within the limits of this study, diabetic animals presented distortion in periodontal attachment and an aggressive bone loss pattern when compared to the healthy controls, suggesting that DM has an independent effect on periodontal tissue destruction irrespective of the presence or absence of periodontal disease.