• The Korean Journal of Zoology
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• v.28 no.3
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• pp.166-178
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• 1985

In order to express hepatitis B surface antigen $(HB_sAg)$ containing pre-surface antigen region in mammalian calls, 2.7 kb DNA fragment containing pre-surface region-$HB_sAg$ gene poly(A) addition site of HBV genome was cloned into simian virus 40(SV 40) based chimeric vector pSVOB. 2.7 kb DNA fragment was derived from pHBVD 107 containing tandem copies of the HBV genome in a head-to-tail arrangement by Bgl II digestion. Construction of the vector pSVOE involved the incorporation of SV40 sequences spanning the viral origin of replication and 72 bp repeats (enhancer) into a pBR 322 derivative lacking sequences which inhibit replication in mammalian cells. Bam HI linker was inserted at the Pvu II site in the proximity of SV40 late promoter of pSVOE and named as pSVOB. To construct the recombinant plasmid pSVBS, pHBVD 107 was digested with Bgl II to isolate 2.7kb DNA fragment and the fragment was ligated into the Bam HI site of pSVOB by ligation. Preliminary result showed that the recombinant plasmid pSVBS produced $HB_sAg$ in the monkey cell producing large T antigen (COS cell).

• Radiation Oncology Journal
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• v.18 no.3
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• pp.182-186
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• 2000

Purpose : To determine treatment or이ecol for inoperable esophageal cancer patients, 껜e evaluated survival rate and prognostic factors. Materials and Methods : We evaluated esophageal cancer treated by curative or palliative am in KCCH from 1992 to 1996, retrospectively. Recurrent or underdose case below 40 Gy were excluded. The number of male and female were 35 and 5, respectively. Thirty-eight patients were squamous carcinoma and 2 patients were not biopsy proven. Ten patients were treated with radiation therapy and chemotherapy Median dose of radiation therapy was 59.4 Gy and the range was $40\~60$ Gy. Results : The median survival is 6.5 months and 1-year survival rate was $28.3\%$. Age, location, radiation dose and chemotherapy were not significant prognostic factors. Median survivals of patients with below stage III and over stage IVA were 7.6 and 6.2 months respectively, but it is not significant. Conclusions : The survival for esophageal cancer is very poor. For patients with curative aim, chemotherapy must be considered. For patients with palliative aim, short-term external beam radiation therapy and/or brachytherapy must be considered.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.48-55
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• 2009

Purpose: As Korean nuclear law doesn't have any clear guideline about the dose and the external dose rate(uSv/h) requiring hospitalization in radioactive iodine treated patients, the patients are discharged when they meet the guideline of IAEA Basic Safety Standards(BSS). We measured external dose rate(${\mu}Sv/h$) of inpatient underwent 3700MBq (100 mCi) $^{131}I$ radioiodine treatment and considering external dose rate(${\mu}Sv/h$), residual activity(mCi) and excretion rate(%) we found the time for RA to be lowered from 3700MBq (100 mCi) to 1110 MBq (30 mCi) to give reference to set a guideline for discharge. Materials and Methods: Forty-two patients underwent thyroidectomy and scheduled for radioiodine treatment, who received 3700MBq (100 mCi) of $^{131}I$ orally and had no renal disease were examined. After 1, 2, 4, 8, and 20, 24, 40 hours iodine uptake and before/after the urination, the external dose rate(${\mu}Sv/h$) measured using FH40G-L(Thermo Fisher Scientific Inc., MA) at a distance and a height of 1 m for 20 sec on the average. Results and Conclusions: At 20 hours, the external dose rate was decreased to $49{\pm}13\;{\mu}Sv$/h, namely, 78% of administrated radioactivity was excreted and 814 MBq (30 mCi) was residual, and it met the accepted limit for discharge of (IAEA, BSS) under 1110 MBq (30 mCi) (1 m at 66 uSv/h).

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.325-333
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• 2015

The ventilation systems composed three types of side vent (roll-up) 'SV', side vent+roof vent 'SV+RV', and side vent+roof fan 'SV+RF' with 7.5 m spacing, with specific set point temperatures for ventilation: SV ($35^{\circ}C$ open / $33^{\circ}C$ close), SV+RV or SV+RH ($35^{\circ}C$ open/$33^{\circ}C$ close for root ventilation and $37^{\circ}C$ open / $35^{\circ}C$ close for side vent). In the treatment of SV+RV, although the average daily maximum temperature inside the greenhouse temporarily increased by $38-40^{\circ}C$, thermal stress by high temperature did not occur and the disease incidence (%) of powdery mildew and downy mildew on the oriental melon were 25 - 75% lower than in the conventional SV treatment. In the SV treatment, the disease incidence (%) of powdery mildew and downy mildew were 1.4 - 7.7% and 4.2 - 15.9% for 'Deabakkul', and 20.3 - 22.8% and 2.8 - 11.3%, for 'Ildeungkkul'. The yield for one month was higher in the treatment of SV+RV than those in other treatments, with values of 2,105 kg/10a for 'Deabakkul' and 2,537 kg/10a for 'Ildeungkkul'. The simultaneous treatment with side vent and roof vent resulted in 16.2% higher yield (18.1% higher marketable yield) than that in the SV treatment for 'Deabakkul'.

• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.118-123
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• 2015

The frequency of diagnostic radiation examinations in medical institutions has recently increased to 220 million cases in 2011, and the annual exposure dose per capita was 1.4 mSv, 51% and 35% respectively, compared to those in 2007. The number of chest radiography was found to be 27.59% of them, the highest frequency of normal radiography. In this study, we developed a shielding device to minimize radiation exposure by shielding areas of the body which are unnecessary for image interpretation, during the chest radiography. And in order to verify its usefulness, we also measured the difference in entrance surface dose (ESD) and the absorbed dose, before and after using the device, by using an international standard pediatric (10 years) phantom and a glass dosimeter. In addition, we calculated the effective dose by using a Monte Carlo simulation-based program (PCXMC 2.0.1) and evaluated the reduction ratio indirectly by comparing lifetime attributable risk of cancer incidence (LAR). When using the protective device, the ESD decreased by 86.36% on average, nasal cavity $0.55{\mu}Sv$ (74.06%), thyroid $1.43{\mu}Sv$ (95.15%), oesophagus $6.35{\mu}Sv$ (78.42%) respectively, and the depth dose decreased by 72.30% on average, the cervical spine(upper spine) $1.23{\mu}Sv$ (89.73%), salivary gland $0.5{\mu}Sv$ (92.31%), oesophagus $3.85{\mu}Sv$ (59.39%), thyroid $2.02{\mu}Sv$ (73.53%), thoracic vertebrae(middle spine) $5.68{\mu}Sv$ (54.01%) respectively, so that we could verify the usefulness of the shielding mechanism. In addition, the effective dose decreased by 11.76% from $8.33{\mu}Sv$ to $7.35{\mu}Sv$ before and after wearing the device, and in LAR assessment, we found that thyroid cancer decreased to male 0.14 people (95.12%) and female 0.77 people (95.16%) per one million 10-year old children, and general cancers decreased to male 0.14 people (11.70%) and female 0.25 people (11.70%). Although diagnostic radiation examinations are necessary for healthcare such as the treatment of diseases, based on the ALARA concept, we should strive to optimize medical radiation by using this shielding device actively in the areas of the body unnecessary for the diagnosis.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.297-302
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• 2017

In this study, the generation of photoneutrons between the 10 MV FF mode and the FFF mode was evaluated and the amount of photoneutrons generated by the 10 MV and 15 MV energy changes in the FFF mode was evaluated. The generated neutrons were evaluated at 13 measurement points and the KTEPC was used to collect the generated neutrons. 10 MV FF mode was measured at 10 MV FF mode and FFF mode at all measurement points. In the superior direction, 0.455mSv and 0.152mSv were the largest, and more than 33% optical neutron was generated in FF. 10 MV in FFF mode, 15 MV in 15 MV, and 0.402 mSv in the direction of Superior, and 6.9% in the direction.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.329-334
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• 2018

Radon which is natural component of air is a colorless and odorless radioactive gas. Radon exposure can also occur from some building materials if they are made from radon-containing substances by breathing. In this study, The radiation dose of radon concentration was detected at 8 buildings of the A university during 3-month from June. 2017 to August. 2017. We detected indoor radon exposure at 8 building of the university and estimated annual effective dose. The radon concentration of Hall G and Hall F of the A university represented 81 and $14Bq/m^3$ respectively and average indoor radon concentration represented $41.63Bq/m^3$. Average effective dose was estimated 0.40 mSv/y, maximum effective dose was 0.78 mSv/y and minimum effective dose was 0.13 mSv/y respectively. University is the place that students spend the almost whole time. We suggest ventilation and appropriate management of a building, which could reduce the natural radiation exposure by radon concentration.

• Journal of Conservation Science
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• v.21
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• pp.41-48
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• 2007

The resistance for atmospheric corrosion of the conventional 5 epoxy resins (Araldite rapid, Araldite AW 106, Araldite SV 427, Devcon, and CDK), those were used to restoration of the iron relics, were investigated in this study. Temperature, UV light, and water were chosen for the factors of the atmospheric corrosion. The drastic voluminous changes of the epoxy resins were found at the temperature range between $40^{\circ}C$ and $70^{\circ}C$ After UV exposure, the colors of the epoxy resins were severely changed. In case of the indoor exposure the chroma value(${\Delta}E$) of the resins were less than 2, which showed a little changes of the colors. The result of the water contact angle test was Araldite rapid>AW 106>Devcon>SV 427>CDK. Although the contact angles of the resins were reduced by UV exposure, SV 427 was stable comparatively.

• Molecules and Cells
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• v.37 no.7
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• pp.562-567
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• 2014

Human Hertwig's epithelial root sheath/epithelial rests of Malassez (HERS/ERM) cells are epithelial remnants of teeth residing in the periodontium. Although the functional roles of HERS/ERM cells have yet to be elucidated, they are a unique epithelial cell population in adult teeth and are reported to have stem cell characteristics. Therefore, HERS/ERM cells might play a role as an epithelial component for the repair or regeneration of dental hard tissues; however, they are very rare population in periodontium and the primary isolation of them is considered to be difficult. To overcome these problems, we immortalized primary HERS/ERM cells isolated from human periodontium using SV40 large T antigen (SV40 LT) and performed a characterization of the immortalized cell line. Primary HERS/ERM cells could not be maintained for more than 6 passages; however, immortalized HERS/ERM cells were maintained for more than 20 passages. There were no differences in the morphological and immunophenotypic characteristics of HERS/ERM cells and immortalized HERS/ERM cells. The expression of epithelial stem cell and embryonic stem cell markers was maintained in immortalized HERS/ERM cells. Moreover, immortalized HERS/ERM cells could acquire mesenchymal phenotypes through the epithelial-mesenchymal transition via TGF-${\beta}1$. In conclusion, we established an immortalized human HERS/ERM cell line with SV40 LT and expect this cell line to contribute to the understanding of the functional roles of HERS/ERM cells and the tissue engineering of teeth.

• The Korean Journal of Zoology
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• v.17 no.2
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• pp.51-56
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• 1974

Newborn Armenian and Chinese hamsters inoculated with adenovirus type 12 developed undifferentiated small cell tumors as early as 27 days after inoculation in the Chinese hamsters and within 30$\\sim$45 days in the Armenian hamsters. These tumors were transplantable and epithelial-like cell in morphology. Cultures of 6 tumors underwent spontaneous reversion to fibroblast-like morphology during the 14$\\sim$20 in vitro passages in the absence of chromosomal disturbances. While epithelial-like tumor derivatives were oncogenic and positive for the T-antigen, fibroblast-like revertants were non-oncogenic and negative for the T-antigen. Two other tumor derivatives reverted to fibroblast-like forms, immediately following exposure to SV40. These lacked the adenovirus T-antigen but were positive for the SV40 T-antigen and formed sarcomas in animals.