• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.262-268
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• 2006

The purpose of this in vitro study was to evaluate the remineralizing effects of Nd : YAG laser irradiation and fluorides application on primary tooth enamel eroded by acidic drink. The materials were 30 sound primary teeth with intact smooth enamel surfaces. They were demineralized with Coca-cola at $37^{\circ}C$ for 12 hours and then irradiated by Nd: YAG laser with 6W power, $50mJ/cm^2$ energy density. and 20Hz pulse repetition. After laser irradiation, teeth were treated by three kinds of fluorides : (1) 0.05% NaF solution, (2) 1.23% APF gel and (3) 0.1% fluoride varnish. Diagnodent scores and microhardness (VHN) were measured before and after the each treatment. The results were as follows: 1. Diagnodent scores decreased to 23.51% from the initial after demineralization, and then increased to 37.37% after laser irradiation, and to 51.34% after fluoride treatment. There were significant differences between the total scores of initial, demineralization, laser irradiation and fluoride treatment (P<0.05). There was no significant difference between scores after fluoride treatment according to fluoride types. 2. Microhardness(VHN) decreased to 33.58% from the initial after demineralization and then increased to 43.99% after laser irradiation, and to 51.38% after fluoride treatment. There were significant differences between the total scores of initial, demineralization, laser irradiation and fluoride treatment (P<0.05). There was no significant difference between scores after fluoride treatment according to fluoride types.

• Investigative Magnetic Resonance Imaging
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• v.13 no.1
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• pp.31-39
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• 2009

Purpose : This study proposes the keyhole method in order to improve the time resolution of the proton resonance frequency(PRF) MR temperature monitoring technique. The values of Root Mean Square (RMS) error of measured temperature value and Signal-to-Noise Ratio(SNR) obtained from the keyhole and full phase encoded temperature images were compared. Materials and Methods : The PRF method combined with GRE sequence was used to get MR temperature images using a clinical 1.5T MR scanner. It was conducted on the tissue-mimic 2% agarose gel phantom and swine's hock tissue. A MR compatible coaxial slot antenna driven by microwave power generator at 2.45GHz was used to heat the object in the magnetic bore for 5 minutes followed by a sequential acquisition of MR raw data during 10 minutes of cooling period. The acquired raw data were transferred to PC after then the keyhole images were reconstructed by taking the central part of K-space data with 128, 64, 32 and 16 phase encoding lines while the remaining peripheral parts were taken from the 1st reference raw data. The RMS errors were compared with the 256 full encoded self-reference temperature image while the SNR values were compared with the zero filling images. Results : As phase encoding number at the center part on the keyhole temperature images decreased to 128, 64, 32 and 16, the RMS errors of the measured temperature increased to 0.538, 0.712, 0.768 and 0.845$^{\circ}C$, meanwhile SNR values were maintained as the phase encoding number of keyhole part is reduced. Conclusion : This study shows that the keyhole technique is successfully applied to temperature monitoring procedure to increases the temporal resolution by standardizing the matrix size, thus maintained the SNR values. In future, it is expected to implement the MR real time thermal imaging using keyhole method which is able to reduce the scan time with minimal thermal variations.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.181-187
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• 2004

Preparations of mesoporous materials using various templates and their applicability have been intensively investigated for many years. We studied on synthesizing mesoporous Ti02 with pores in which sensitive compounds having weak physico-chemical properties such as thermal or UV irradiation and low solubility in solvent are trapped. Prior to trapping OMC in the pores of mesoporous titania, OMC was nano-emulsified in O/W system using Lecithin. Thereafter the OMC was trapped in the pores of mesoporous titania using sol-gel method. Main focus of this work is to prepare OMC-trapped mesoporous titania and to trace the stability and solubility of nano-emulsified OMC in the pores of mesoporous titania, and compared with that of mesoporous silica. OMC-trapped mesoporous Inorganic-Organic hybrid titania showed higher factors in sun protecting and a skin penetration phenomenon was reduced.

• Tuberculosis and Respiratory Diseases
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• v.48 no.1
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• pp.24-32
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• 2000

Purpose: Microsatellite instability(MSI) is frequently used as an indicator of microsatellite mutator phenotype(MMP) tumors. MSI has been observed in a percentage of non-small cell lung cancer(NSCLC). However, its role in tumorigenesis of NSCLC remains unknown. The frequency and pattern of MSI in NSCLC were evaluated and clinical parameters of MSI-positive tumors with those of MSS(microsatellite stable) tumors were compared. Materials and Methods: Twenty surgically resected NSCLCs were analyzed for 15 microsatellite markers located at chromosomes 3p and 9p. The peripheral blood lymphocytes of patients were used as the source of the normal DNA. Results: 1) Of 20 cases, 8(40%) demonstrated MSI. 2) Instability was observed more frequently in tri- and tetra-nucleotide repeats than in dinucleotide repeats. In all cases, instability appeared as a shift of individual allelic bands. 3) LDH was observed in 10(50%) of 20 tumors analyzed. 4) Of 20 cases, MSI-H tumor(showing MSI in the majority of markers) was absent. There were 5 MSI-L tumors(showing MSI in a greater than 10% of markers). 5) No significant difference was observed between MSI-L tumors and MSI-negative tumors in terms of clinicopathologic features such as pack-year history of smoking, histologic subtype, and(delete) stage of disease. There was also no significant difference in the incidence of LDH in relation to the status of MSI. Conclusion: These data strongly suggest that MSI plays different roles in lung and colon cancer. MMP pathway appears to be far less important in the tumorigenesis of NSCLC, caused mainly by cigarette smoke, with little familial tendency.

• Restorative Dentistry and Endodontics
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• v.35 no.5
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• pp.387-394
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• 2010

Objectives: The purpose of this study was to evaluate the whitening efficacy and longevity of home bleaching. Materials and Methods: A total of 28 patients were divided into either experimental group (Opalescence F; 15% carbamide peroxide) or control group randomly. The patients in experimental group were instructed to wear individual trays applied with bleaching gel for 2 hours a day for 4 weeks. Any treatments weren't applied to the patients in control group. The color measurements of central incisors, lateral incisors & canines of upper and lower arch were recorded at base line, immediately after the finishment of treatmemt (4 weeks), 8 weeks and 12 weeks using Colorimeter (Chroma Meter, 2600d Konica Minolta co.) and Vitapan classical shade guide (Vita Zahnfabrik). Results: A significantly stronger color change was observed for overall teeth samples in experimental group immediately after treatment (at 4 weeks) compared to ones in control group (p < 0.05). There was also a significant difference between baseline and 8 weeks or 12 weeks separately though color rebouncing phenomenon occurred as time went by (p < 0.05). Conclusions: The clinical effecacy and longevity of home bleaching without combined application of in-office bleaching was observed through this experiment.

• Food Science and Preservation
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• v.31 no.1
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• pp.149-160
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• 2024

Dextran is a glucose homo-polysaccharide with a predominantly α-1,6 glycosidic linkage of microbial source and is known to be produced primarily by lactic acid bacteria. However, it can also be obtained through the dextran dextrinase of acetic acid bacteria (Gluconobacter oxydans). The dextrin-based dextran was obtained from rice starch using G. oxydans fermentation of rice hydrolysate, and its properties were studied. Both dextrin- and rice hydrolysate-added media maintained the OD value of 6 after 20 h of incubation with acetic acid bacteria, and the gel permeation chromatography (GPC) analysis of the supernatant after 72 h of incubation confirmed that a polymeric material with DP of 480 and 405, which was different from the composition of the substrate in the medium, was produced. The glucose linkage pattern of the polysaccharide was confirmed using the proton nuclear magnetic resonance (¹H-NMR) and the increased α-1,4:α-1,6 bond ratio from 0.23 and 0.13 to 1:2.37 and 1:4.4, respectively, indicating that the main bonds were converted to α-1,6 bonds. The treatment of dextrin with a rat-derived alpha-glucosidase digestive enzyme resulted in a slow release of glucose, suggesting that rice hydrolysate can be converted to dextran using acetic acid bacteria with glycosyltransferase activity to produce high-value bio-materials with slowly digestible properties.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.45-49
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• 2010

Purpose: Several radiopharmaceuticals were used for cisternography. But recently, due to more short acquisition time, high resolution than other radiopharmaceuticals like In-111 DTPA, we were using Tc-99m DTPA in cisternography. Using of Tc-99m DTPA for intrathecal, was not officially recognised by the FDA. And there are matters of aseptic meningitis, muscular tetany, seizures by inappropriate radiopharmaceuticals handling. So, it is necessary to prevent adverse reactions while handling the radiopharmaceuticals using in cisternography. Therefore, this study aims to evaluation of usefulness and procedures for safety of radiopharmaceuticals in cisternography. Materials and Methods: Subjects were 12radioactive tracer vials using in cisternography in 2008 Dec. 16 - 2009 Dec. 30. (1) Radioactive tracer Vial test - We were measured NaPertechnetate radiation dose and volume, normal saline volume for dilution, source volume and dose activity for patient injection. And then, calculated mass of pure DTPA. (2) Bacterial endotoxin test - We performed pyrogen test using by negative/positive control vials which was added normal saline 0.2 mL and added normal saline 0.1 mL, Tc-99m DTPA 0.1 mL in test control vial. And then, reacted by digital hot plate in $37.5^{\circ}C$ for 1 hour and compared of gel-clot in each control vials. (3) Compliance safety procedure - We were checked safety issues and wrote out a safety procedure exam sheet. Results: (1) Radioactive tracer Vial test - Mass of DTPA per dose for patient injection (mg) was 0.88 (mg) on average, and Mass of DTPA per volume for patient injection (mg) was 0.74 (mg) on average. (2) Bacterial endotoxin test - All control test vials showed negative reactions. (3) Compliance safety procedure - We were checked safety issues and wrote out a safety exam sheet in all the exams. So, there were no adverse reactions. Conclusion: We could examine easier to safety tests using by Techscan - DTPA (Mallinckrodt): CaNa3. Each test results were passed the safety tests and there are no adverse reactions. The use of Tc-99m DTPA for cisternography, always has been become an issue. Since it has occur adverse reaction while examine the cisternography using by Tc-99m DTPA, it needs to set up the 'Standard Operating procedures'.