• Bulletin of the Korean Chemical Society
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• 제28권11호
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• pp.1951-1957
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• 2007

A new synthetic strategy based on the acid-base catalyzed sol-gel method was developed for the preparation of a series of mesoporous TiO2 nanoparticles. A key feature of the method involves a gradual change in pH (0.8- 9) during the sol-gel transition, which guarantees easy introduction of mesoporosity without relying on the well-established sonochemical or template approach. In addition, this method leads to the exclusive formation of the anatase phase stable enough to the calcination temperature up to 600 oC. The physicochemical properties of the particles in the series were characterized by various spectroscopic and analytical techniques such as wide-angle XRD, SAXRD, BET surface area, FE-SEM, TEM, FT-IR, TGA, and XPS. The photocatalytic efficiency of these materials was investigated for the oxidation of toluene under UV-irradiation. All but T-ad in the series exhibited high photocatalytic activity pushing the reaction into completion within 3 h. The reaction followed the first order kinetics, and the rate reaches as high as 3.9 × 10?2/min which exceeds the one with the commercially available Degussa P-25 by a factor of 3.2. When comparison is made among the catalysts, the reactivity increases with increase in the calcination temperature which in turn increases the crystallinity of the anatase phase, thus revealing the following rate orders: T-3 < T-4 < T-5 < T-6.

• 대한미생물학회지
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• 제35권2호
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• pp.171-180
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• 2000

Ninety two strains of Streptococcus pyogenes were isolated from patients with pharyngitis, scarlet fever, skin infection, and invasive streptococcal infections in Seoul, Korea from January to December, 1998. All isolates were epidemiologically characterized by T protein serotype, and serum opacity factor (OF) detection to phenotypes. To analyze the genetic relationship, fifty two isolates including 32 erythromycin-clindamycin (Em-Cm) resistant strains, 20 antimicrobial susceptible strains were attempted to the pulsed-field gel electrophoresis (PFGE). T protein serotype showed 16 kinds in distribution including T12 and T4. Among the total isolates, 40 strains (43.5%) belonged to the T12 serotype and twenty strains (21.7%) to T4 serotype. On the other hand, when infection aspect of S. pyogenes isolates were analysed by T serotype distribution, T12 type was predominant for pharyngitidis which contributed to 21 strains (53%) and for skin infection isolates which contributed to 11 strains (28%), respectively. In case of T4 type, it was the most predominant pharyngitidis isolates which contributed to 8 strains (40%). In T serotype distribution of Em-Cm resistant strains, 27 strains (84%) of the thirty two showed T12 serotype. In minimum inhibitory concentration (MIC) values of Em-Cm resistance isolates, thirty two isolates showed resistant to erythromycin 27 strains (84%), had high MIC of >$128\;{\mu}g/ml$. And also to clindamycin, twenty two strains (69%) had high MIC of >$128\;{\mu}g/ml$. When OF detection of Em-Cm resistance of S. pyogenes isolates were analyzed by T serotype distribution, T12 serotype isolates revealed that all of the isolates except one strain were OF negative. In PFGE profile analysis to Em-Cm resistance isolates, of the twenty seven, Em-Cm resistance of T12 serotype isolates, 26 strains showed identical PFGE profile and all of these isolates revealed that OF negative. Eighty four percent of Em-Cm resistance S. pyogenes isolates had identical phenotype and PFGE profile. These results strongly suggested that the Em-Cm resistant S. pyogenes isolates from Seoul area showed close genetic correlation and PFGE could be available tool for molecular epidemiology.

• Journal of Periodontal and Implant Science
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• 제30권1호
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• pp.11-27
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• 2000

The purpose of this study was to evaluate the clinical effects of Dipotassium glycyrrhizinate, Allantoin, Hinokitiol, Cetylpyridinium chloride containing gel($Dentheth^{(R)}$) on periodontitis. 41 patients with sites having pocket depth of 4-6mm were selected for the study. We classified 2 groups which consisted of 21 patients in the test group(exp.) and 20 patients in the control(placebo) respectively. Following a baseline examination, plaque and calculus were removed and then the experimental gel were handed out to the patients and topical application regimens were initiated. During the 4-week experimental period, pocket depth, bleeding on probing, gingival index, plaque index as a clinical parameters were measured in the baseline, 2 weeks, 4 weeks respectively. A questionnaire was delivered to each patients in 2 weeks, 4 weeks respectively. The results were as follows : 1. Probing pocket depth showed a significant difference in the Exp. group compared with the control group in the changes from baseline to 2 weeks(p<0.05), but there was no significant difference between the groups in the changes from baseline to 4 weeks, from 2 weeks to 4 weeks(p<0.05). 2. The Exp. group showed a significant difference compared with the control group in the changes from baseline to 2 weeks, from baseline to 4 weeks, from 2 weeks to 4 weeks in bleeding on probing(p<0.05). 3. The gingival index showed a significant difference compared with the control group in the changes from baseline to 2 weeks, from baseline to 4 weeks, from 2 weeks to 4 weeks after 4 weeks use of a gel(p<0.05). 4. The plaque index showed a significant difference in the Exp. group compared with the control group in the changes from baseline to 2 weeks(p<0.05), but there was no significant difference between the groups in the changes from baseline to 4 weeks, from 2 weeks to 4 weeks(p<0.05). 5. A questionnaire was consisted of 5 kinds as to bleeding, pus discharge, pain, burning sensation, patient's satisfaction and all of the questions showed a significant difference compared with the control group in the changes from 2 weeks to 4 weeks(p<0.05). 6. During the 4-week experimental period, important side-effects were not finded out, but each groups had one patient appealed nausea or discomfort respectively. These results indicate that application of periodontitis medical gel was useful as an additional aid of mechanical treatment.

• Environmental Analysis Health and Toxicology
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• 제16권4호
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• pp.197-204
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• 2001

Endocrine disruption in crucian carp (Carassius auratus) living in the branch of Han River were examined. Vitellogenin level in plasma was measured using ELISA system and aromatase mRNA level in brain was observed using RT-PCR technique. In all female fish, vitellogenin levels were in the range of 20∼40 $\mu\textrm{g}$/ml and aromatase mRNA expression could be detected on the agarose gel after RT-PCR. However, in case of males, vitellogenin level was elevated in only one fish, while vitellogenin was hardly detected in others. Aromatase was expressed in all males although the levels were relatively lower than the level in female fish. Testis-ova and any other histological changes of reproductive organ were not shown in both sexes.

• Journal of Nutrition and Health
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• 제3권3호
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• pp.161-166
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• 1970

One male in the former group of 2110 Korean males of the Republic of Korea Army stationed Taegu. And two males and one female in the later group of 4590 Korean school children and university students in Seoul and Taejuon were found to have a slow hemoglobin in addition to normal hemoglobin A. In all four subjects the slow component migrated at a rate characteristic of the G hemoglobin. The overall incidence of the variant in the present group of Koreans was low: 4 in 6700 or 0.06 percent. It appears significant that no insistence of hemoglobin E were found among these Korean subjects. Hemoglobin E has been found among numerous ethnic groups of Southeast Asia and the variant most frequently appeared in Chinese subject. By Urea-Starch-Gel Electrophoresis in Alkaline PH and A.I. Chernoff method was demonstrated that another 3 cases of abnormal hemoglobin also were beta-chain variants. This was reconfirmed by Hybridization Experiment with canine hemoglobin. And the results of family test of 3 case of abnormal hemoglobin were heterozygous carrier.

• 한국환경성돌연변이발암원학회지
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• 제22권2호
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• pp.83-89
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• 2002

The single cell gel electrophoresis (comet) assay is one of the useful tools for the study of genetic damage in humans exposed to environmental mutagens and carcinogens. This study was undertaken to evaluate the status of DNA damage in peripheral lymphocytes depending on their sex, age, smoking habits, and other factors in normal healthy Korean population. The 99 volunteers included in the study and out of these, 36 volunteers were smoker and 63 volunteers were non-smoker aged between 20-59 years. All individual answered a questionnaire that assessed their general information including smoking habits and the extent of the environmental tobacco smoke (ETS) exposure, and blood samples were obtained. There was a statistically significant difference in the extent of DNA damage between smoker and non-smoker (p<0.001). A significant difference was also observed between male and female (p<0.001) and amongst the different group of age (p<0.005), however, correlation analysis showed that only smoking habit was a significant factor for DNA damage. No significant effect of smoking duration, number of cigarettes smoking a day, SPY (smoke pack years) in smokers and environmental tobacco smoke exposure in non-smokers on the status of DNA damage was observed.

• Journal of Pharmaceutical Investigation
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• 제32권4호
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• pp.259-265
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• 2002

Piroxicam is one of the NSAID, which is used in the systemic and topical treatment of a variety of inflammatory conditions. Conventionally, for topical use, the drug is formulated in gel. We designed an phonophoretic drug delivery system to investigate the piroxicam permeability and the influence of ultrasound application (continuous mode, pulsed mode), frequency (1.0 MHz, 3.0 MHz) and intensity $(1.0\;w/cm^2,\;1.5\;w/cm^2,\;2.0\;w/cm^2)$ with 0.5% piroxicam gel. Per cutaneous absorption studies were performed in vitro models to determine the rate of drug absorption via the skin. Permeation study using hairless mouse skin was performed at $37^{\circ}C$ using buffered saline (pH 7.4, 10% propylene glycol solution) as the receptor solution. Anti-inflammatory activity was determined using carrageenan-induced foot edema model in rat. A pronounced effect of ultrasound on the skin absorption of the piroxicam was observed at all ultrasound energy level studied. Ultrasound was carried out for 10 hr. The highest permeation was observed at intensity of $2.0\;w/cm^2$, frequency of 1.0 MHz and continuous output. The inclusion of phonophoresis was found to improve significantly the skin permeation in vitro and the anti-inflammatory activity in vivo.

• Journal of Microbiology and Biotechnology
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• 제23권1호
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• pp.106-117
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• 2013

Microbial enhanced oil recovery (MEOR) is one of the most economical and efficient methods for extending the life of production wells in a declining reservoir. Microbial consortia from Wafra oil wells and Suwaihat production water, Al-Wusta region, Oman were screened. Microbial consortia in brine samples were identified using denaturing gradient gel electrophoresis and 16S rRNA gene sequences. The detected microbial consortia of Wafra oil wells were completely different from microbial consortia of Suwaihat formation water. A total of 33 genera and 58 species were identified in Wafra oil wells and Suwaihat production water. All of the identified microbial genera were first reported in Oman, with Caminicella sporogenes for the first time reported from oil fields. Most of the identified microorganisms were found to be anaerobic, thermophilic, and halophilic, and produced biogases, biosolvants, and biosurfactants as by-products, which may be good candidates for MEOR.

• 한국환경보건학회지
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• 제15권1호
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• pp.63-73
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• 1989

The purposes of this study were to find out the heavy metal and antibiotic resistant coliform bacteria from mineral water and the resistant factors. For the experiment, mineral water samples were taken from A area and B area during the period from march to July, 1988. The results of the experiment were as follows 1. From mineral water, eleven resistant coliforms and one susceptible coliform were isolated. 2. All resistant isolates harbored diverse plasmids of ranged ca. 14-54kb. 3. Susceptible coliform harbored a only plasmid of ca. 2.8 kb. 4. All resistant isolates harbored common size of plasmid of ca. 14kb. 5. As a result of the transformation and agarose gel electrophoresis experiments, resistant factor was R-plasmid. In conclusion, It is suggested that heavy metal contamination of mineral water is the selective pressure for the plasmid encoding the tolerance. Heavy metal resistance, in some case, is present with antibiotic resistance. Therefore, heavy metal contamination of mineral water induces antibiotic resistant bacteria.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.160-160
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• 2011

In the present work, $TiO_2$ fiilms supported by porous silica gel with high surface area synthesized by atomic layer deposition(ALD). Porous structure of silica substrate could be maintained even after deposit large amount of $TiO_2$ (500 cycles of ALD process), suggesting the differential growth mode of $TiO_2$ on top surface and inside the pore. All the $TiO_2$-covered silica samples showed improved MB adsorption abilities, comparing to bare one. In addition, when silica surface was covered with $TiO_2$ films, MB adsorption capacity was almost fully recovered by re-annealing process (500$^{\circ}C$, for 1 hr, in ambient pressure), whereas MB adsorption capacity of bare silica was decreased after re-heaing process. FT-IR study demonstrated that $TiO_2$ film could prevent deposition of surface-bound intermediate species during thermal decomposition of adsorbed MB molecules. Photocatalytic activity of $TiO_2$/silica sample was also investigated.