Skin entrance dose for digital and film radiography in Korean dental schools

Cho, Eun-Sang,Choi, Kun-Ho,Kim, Min-Gyu,Lim, Hoi-Jeong,Yoon, Suk-Ja,,Kang, Byung-Cheol 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.4

Purpose : This study was aimed to compare skin entrance dose of digital radiography with that of film radiography and to show the dose reduction achievement with digital systems at 11 dental schools in Korea. Materials and Methods : Forty six intraoral radiographic systems in 11 dental schools were included in this study. Digital sensors were used in 33 systems and film was used in 13 systems. Researchers and the volunteer visited 11 dental schools in Korea. Researchers asked the radiologic technician (s) at each school to set the exposure parameters and aiming the x-ray tube for the periapical view of the mandibular molar of the volunteer. The skin entrance doses were measured at the same exposure parameters and distance by the technician for each system with a dosimeter (Multi-O-Meter : Unfors instruments, Billdal, Sweden). Results : The median dose was 491.2 μGy for digital radiography and 1,205.0 μGy for film radiography. The skin entrance dose digital radiography was significantly lower than that of film radiography (p<0.05). Conclusion : Fifty-nine percent skin entrance dose reduction with digital periapical radiography was achieved over the film radiography in Korean dental schools.

제주 성상 S/S MTr #1 행원 풍력단지 전압해석

김상준(Sang-Jun Kim),조민호(Min-Ho Cho),윤기갑(Gi-Gab Yoon),장상옥(Sang-Ok Jang),안정식(Jeong-Shik Ahn) 대한전기학회 2003 대한전기학회 학술대회 논문집 Vol.2003 No.11

Metal stain on monolithic zirconia restoration: A case report

Min-Sang Cha,Sang-Woon Lee,Yoon-Hyuk Huh2,Lee-Ra Cho2,Chan-Jin Park 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.2

In restorative treatment using fixed dental prostheses, dentists should select appropriate restoration material among various types of dental materials. The strength, marginal fit, esthetics, wear resistance, biocompatibility, and cost are important factors in the choice of restoration materials. The present case showed a surface stain on a monolithic zirconia restoration that was due to wear between the monolithic zirconia restoration and the base metal alloy restoration. This phenomenon was confirmed by surface roughness measurement and electron probe micro-analysis.

시간의 흐름에 따른 핸드폰의 품질동태성에 관한 연구

윤성필(Sung-Pil Yoon),임성욱(Sung-Uk Lim),박만희(Man-Hee Park),조인희(In-Hee Cho) 한국엔터테인먼트산업학회 2010 한국엔터테인먼트산업학회논문지 Vol.4 No.3

본 연구는 선행연구에서 조사된 핸드폰의 고객요구속성을 Kano 모델의 품질특성에 적용하여 시간의 흐름에 따라 어떤 변화가 있는지를 살펴보고자 한다. 또한 고객들의 새로운 요구속성이 나타났는지도 함께 살펴보고자 한다. 많은 문헌과 선행연구에서 나타나고 있는 시간에 따른 품질특성의 이동이 매력적 품질에서 일원적 품질로 일원적 품질에서 당연적 품질로 변화하는 진부화(陳腐化)현상이 나타나는지도 함께 살펴보고자 한다. In this study, previous research (Sung-Uk Lim, 2004) surveyed in customer demand for mobile phones the quality characteristics of properties applied to the Kano model, the flow of time, depending on whether any changes will be discussed. In addition, our customers" new requirements will be examined along with the property map appeared. The movement of time-dependent quality characteristics appeared in many previous studies Obsolescence Phenomenon - from Attactive Quality Element to One-Dimensional Quality Element, from One-Dimensional Quality Element to Must-Be Quality Element - may appear be examined together.

Efficient Interleukin-21 Production by Optimization of Codon and Signal Peptide in Chinese Hamster Ovarian Cells

( Hee Jun Cho ),( Byung Moo Oh ),( Jong-tae Kim ),( Jeewon Lim ),( Sang Yoon Park ),( Yo Sep Hwang ),( Kyoung Eun Baek ),( Bo-yeon Kim ),( Inpyo Choi ),( Hee Gu Lee ) 한국미생물 · 생명공학회 2019 Journal of microbiology and biotechnology Vol.29 No.2

Interleukin-21 is a common γ-chain cytokine that controls the immune responses of B cells, T cells, and natural killer cells. Targeting IL-21 to strengthen the immune system is promising for the development of vaccines as well as anti-infection and anti-tumor therapies. However, the practical application of IL-21 is limited by the high production cost. In this study, we improved IL-21 production by codon optimization and selection of appropriate signal peptide in CHO-K1 cells. Codon-optimized or non-optimized human IL-21 was stably transfected into CHO-K1 cells. IL-21 expression was 10-fold higher for codon-optimized than non-optimized IL-21. We fused five different signal peptides to codon-optimized mature IL-21 and evaluated their effect on IL-21 production. The best result (a 3-fold increase) was obtained using a signal peptide derived from human azurocidin. Furthermore, codon-optimized IL-21 containing the azurocidin signal peptide promoted IFN-γ secretion and STAT3 phosphorylation in NK-92 cells similar to codon-optimized IL-21 containing original signal peptide. Collectively, these results indicate that codon optimization and azurocidin signal peptides provide an efficient approach for the high-level production of IL-21 as a biopharmaceutical.

C3H 생쥐에서 자외선 B의 집중조사와 분할조사가 표피내 랑게르한스 세포의 회복에 미치는 영향

구상완,한승경,박윤기,조무연 ( Sang Wahn Koo,Seung Kyung Hann,Yoon Kee Park,Moo Yon Cho ) 대한피부과학회 1991 대한피부과학회지 Vol.29 No.4

N/A The Effect on the Recovery of Epidermal Langerhans Cells in C3H Mice after Single and Fractionated Exposure of Ultraviolet B Irradiation Sang-Wahn Koo, M.D., Seung Kyung Hann, M.D., Yoon-Kee Park, M.D., Moo Yon Cho, M.D. Department of Dermatology, Yonsei University College of Medicine Seoul, Korea The study was undertaken to see the recovery in epidermal Langerhans cells in relation to time after UVB irradiation through different amounts and ways of exposure in C3H mice. We irradiated the ears of C3H mice with UVB 200mJ/㎤ and 400mJ/㎤ in a single dose at one time and 5 fractionated doses for 5 days and 10 fractionated doses for 10 days and performed biopsies on the ears of the control and experimental groups after, 2, 7, 14, 21 days of irradiation and stained them by the immunoperoxidase method. The results are summarized as follows. 1. A more significant decrease in the number of Ia-positive epidermal Langerhans cells was observed in single-dose-exposed group than fractionated-dose-exposed groups on the second day of irradiation. 2. On the seventh day of exposure, the number of the Ia-positive epidermal cells in single-dose-exposed group returned to normal, but in fractionated-dose-exposed groups the number of Langerhans cells decreased most remarkably. 3. In fractionated-dose-exposed groups, the number of Langerhans cells returned to normal on the 14th or 21st day of expposure. (Kor J Dermatol 29(4) : 459-465, 1991)

수종의 광독성 약물투여 후 시간에 따른 피부농도 및 최소 광독량에 관한 연구

박윤기,조무연,한승경,임성빈 ( Yoon Kee Park,Moo Yon Cho,Seung Kyung Hann,Sung Bin Im ) 대한피부과학회 1991 大韓皮膚科學會誌 Vol.29 No.5

N/A The Skin Concentration and Minimal Phototoxic Dose Following Administration of Phototoxic Drugs as a Function of Time Yoon-Kee Park, M.D., Moo Yon Cho, M.D., Saung Kyung Hann, M.D., Sungbin im, M.D. Department of Dermatology Yonsei Univeraity College of Medicine, Seoul, Korea Psoralen photochemotherapy(PUVA) is defined as a treatment that depends on the interaction of a photosensitizing substance, psoralen, and long wave jltraviolet(UVA) radiation that results in therapeutically beneficial effects. The rationale of its use is to clear skin disease by repeated controlled phototoxic reactions. The efficacy of PUVA depends on the drug, the UVA dose and wave length, the individual sensitivity to the phototoxic reaction and on the disease to be treated. However, the major factor is the amount of psoralen at the site of photochemical reaction in skin. Daspite the extensive experiences which have now accumulated in the use of PUVA, the relationship between the therapeutic response and phototoxicity as it occurs in normal skin is not established. Comparative data on different psoralen molecules and their skin sensitizing ability are required. From studies on the skin concentration using HPLC and minimal phototoxic dose following oral administration, intraperitoneal administration, a bath of phototoxic drugs as a function of time in guinea pigs, the following results are obtained. 1. The skin concentration of phototoxic drugs after oral administration peaked at 1.5 hours, and the concentration of 8-methoxypsoralen(8-MOP) was 3.7 times greater than that of 5-methoxypsoralen(5-MOP). The skin concetration of 4,5,8-trimethylpsoralen(TMP) was not detected in this study(limit of sensitivity 5ng/g). 2. The skin conentration of phototoxic drugs after intraperitoneal administration peaked at 30 minutes, and the concentration of 8-MOP was slightly greater than that of 5-MOP. The skin concentration of TMP was not detected in this study(limit of sensitivity 5ng/g). 3. The skin concentration of phototoxic drugs after bathing peaked immediately after bathing, and the skin concentrations of phototoxic drugs after bathing decreased in the order of 5-MOP, TMP, and 8-MOP. 4. The minimal phototoxic dose of phototoxic drugs after oral administration was lowest at 1.5 hours, and the minimal phototoxic dose of 8-MOP was 8 times less than 5-MOP, 24 times less than TMP. The phototoxicity of 8-Mop after oral administration was strongest. The time of lowest phototoxic dose and highest skin concentration was the same. 5. The minimal phototoxic dose of phototoxic drugs after intraperitoneal administration was lowest at 30 minutes, and the minimal phototoxic dose of 8-MOP was 1.3 times less than 5-MOP, 5.7 times less than TMP. The phototoxicity of 8-MOP after intraperitoneal administration was strongest. The time of lowest phototoxic dose and highest skin concentration was same. 6. The minimal phototoxic dose of phototoxic drugs after bathing was lowest at 15 minutes. The minimal phototoxic dose of 8-MOP was not significantly different but was significantly greater than that of 5-MOP.

Altitudinal Distribution of Korean Endemic Species, Silpha koreana, (Coleoptera, Silphidae) at Mt. Mindung, Gangwon Province

Cho, Young-Bok,Kim, Do-Seong,Yoon, Sung-Mahn,Oh, Kwang-Sik,Min, Hong-Ki national science museum of korea 2008 Journal of Korean nature Vol.1 No.1

The study on the altitudinal distribution of Silpha koreana by using bait traps was conducted from Mt. Mindung (1119 m, alt.), Gangwon province on June 3rd to 4th, 2007. Each five bait traps at interval 1 m were placed at per plot along the following altitudes, 1100 m, 1000 m, 900 m, 800 m and 700 m. As a result, the highest density was in 1100m which was collected 176 individuals but nothing was collected in the sites of 800 m and 700 m. This species is shown the typical characteristic with mountane adaptation, preferring grasses or shrubs.

Study on the Variance of N₂O Concentration after Air Pollution Prevention Facility in Bituminous Coal-Firing Power Plant

Cho, Chang-Sang,Kim, Min-Wook,Kang, Seong-Min,Hong, Yoon-jung,Jeon, Eui-Chan American Chemical Society 2017 Energy & fuels Vol.31 No.4

<P>This study intends to check effects,of air pollutant prevention facilities in bituminous coal-fired power plants on N2O gas emission concentration. Bituminous coal-fired power plants install and operate air pollution prevention facilities to prevent air pollution. The exhaust gases generated by such coal-fired power plants generally pass through a flue gas denitrification facility for removal of nitrogen oxides, a dust collector for removal of suspended matter, and a flue gas desulfurization facility for removal of sulfur oxides, and are emitted through a smokestack. To check the effects of prevention facilities on N2O e mission concentrations, sampling is necessary at the front end and rear end of each prevention facility. Exhaust gases were collected from the front and rear ends of the flue gas denitrification facility (SCR), the rear end of the electric dust collector (EP), and the measurement hole on the smokestack to analyze the concentrations of the gases. According to the results, it was identified where N2O emission concentrations were affected by air pollution prevention facilities. In which air pollutant prevention facilities these differences occurred was-analyzed. N2O emission concentration decreased after flue gases passed the flue gas desulfurization facility (FGD)-in all three power plants. The phenome-non of reduction of N2O emission concentrations by bituminous coal-fired power plant FGD is judged attributable to the effect of CaCO3 used in the FGD.</P>

Controlled synthesis of dual-phase carbon-coated Nb₂O₅/TiNb₂O₇ porous spheres and their Li-ion storage properties

Yoon, Sukeun,Lee, Sung-Yun,Nguyen, Tuan Loi,Kim, Il Tae,Woo, Sang-Gil,Cho, Kuk Young Elsevier 2018 Journal of alloys and compounds Vol.731 No.-

<P><B>Abstract</B></P> <P>Dual-phase Nb<SUB>2</SUB>O<SUB>5</SUB>/TiNb<SUB>2</SUB>O<SUB>7</SUB> and carbon-coated Nb<SUB>2</SUB>O<SUB>5</SUB>/TiNb<SUB>2</SUB>O<SUB>7</SUB> porous spheres were synthesized using a simple solvothermal method followed by post-heat treatment. The Nb<SUB>2</SUB>O<SUB>5</SUB>/TiNb<SUB>2</SUB>O<SUB>7</SUB> materials comprised porous spheres with 3-dimensional interconnected microsphere architectures, with a homogeneous dispersion of carbon coating the Nb<SUB>2</SUB>O<SUB>5</SUB>/TiNb<SUB>2</SUB>O<SUB>7</SUB> spheres. As the anode for a Li-ion battery, the dual-phase carbon-coated Nb<SUB>2</SUB>O<SUB>5</SUB>/TiNb<SUB>2</SUB>O<SUB>7</SUB> porous spheres delivered a high gravimetric capacity of >247 mA h g<SUP>−1</SUP> with good cycling performance, as well as a high rate capability. The unique and advantageous characteristics of the dual-phase carbon-coated Nb<SUB>2</SUB>O<SUB>5</SUB>/TiNb<SUB>2</SUB>O<SUB>7</SUB> porous spheres for high performance Li-ion batteries are attributed to the synergistic effects of the porous, two-phase structure of the material. Furthermore, the conductive carbon matrix on the spheres provided facile electron transport and an effective alleviation of mechanical strain during cycling. The high electrochemical performance of the dual-phase carbon-coated Nb<SUB>2</SUB>O<SUB>5</SUB>/TiNb<SUB>2</SUB>O<SUB>7</SUB> porous spheres recommends them as a promising anode material for future Li-ion batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Controlled synthesis of dual-phase carbon-coated Nb<SUB>2</SUB>O<SUB>5</SUB>/TiNb<SUB>2</SUB>O<SUB>7</SUB> porous spheres. </LI> <LI> Synergistic effects of the porous, two-phase structure of the material. </LI> <LI> Electrochemical reaction behavior of carbon-coated Nb<SUB>2</SUB>O<SUB>5</SUB>/TiNb<SUB>2</SUB>O<SUB>7</SUB> porous spheres with lithium. </LI> </UL> </P>