K⁺ 통로 조절 약물이 마우스 골격근의 피로현상에 미치는 영향

이기호,류판동,이문한,이항,Lee, Ki-ho,Ryu, Pan-dong,Lee, Mun-han,Lee, Hang 대한수의학회 1995 大韓獸醫學會誌 Vol.35 No.2

The density of ATP-sensitive potassium($K_{APT}$) channels, that open as intracellular ATP concentration falls below a critical level, is very high in skeletal muscle surface membrane and those high density may imply that $K_{ATP}$ channels have very important physiological roles. To elucidate a role of $K_{ATP}$ in relation to fatigue, the modulating effects of potassium channel openers and blockers on the fatigue velocity(FV) of mouse extensor hallucis longus muscle(EHL) were investigated in vitro. Twitch contraction was induced by an electrical field stimulation (EFS: 24-48V, 20ms, 0.2-4Hz) and resulting contraction force was isometrically recorded. The twitch forces were gradually decreased to 25% of initial contraction force(ICF) in $37.52{\pm}1.55sec$($mean{\pm}s.e.m.$, n=135), indicating the fatigue phenomena. The mean velocity for development of the fatigue was measured during the period that twitch force decreased to half($FV_{0/0.5}$) and during the period from half to 25%($FV_{0.5/0.25}$) of ICF. The fatigue was induced once every one hour and the tissue response was stable for up to 4 hours. In control condition, ICF was $5.8{\pm}0.12g$ (n=144) and decreased to 50% of ICF with the mean fatigue velocity of $0.182{\pm}0.006g/sec$($FV_{0/0.5}$, n=135) and from 50% to 25% of ICF with $0.084{\pm}0.004g/sec$($FV_{0.5/0.25}$, n=135). Cromakalim($50{\mu}M$) significantly increased $FV_{0.5/0.25}$(n=4). Glibenclamide($IC_{50}>50{\mu}M$), $Ba^{2+}$($IC_{50}=10{\mu}M$), 4-aminopyridine($FV_{0/0.5}$, $IC_{50}=0.5mM$; $FV_{0.5/0.25}$, $IC_{50}=2mM$) decreased both $FV_{0/0.5}$ and $FV_{0.5/0.25}$ concentration-dependently up to 75%. $TEA^+$(30mM), E-4031($10{\mu}M$), tolbutamide(1mM) decreased $FV_{0.5/0.25}$, but apamin(300nM) and $TEA^+$(10mM) showed no significant effects. Our results suggest that activation of the $K_{ATP}$ channels may be major cause of $K^+$ outflux during development of the fatigue and the isolated EHL muscle could be an useful experimental preparation in studying the fatigue phenomena in skeletal muscle. In addition, the possibility of activation of delayed rectifier during the fatigue development remains to be studied further.

디지털 컨버전스에서의 인터럽션: 멀티 모달리티와 멀티 태스킹 간의 상호 관계를 중심으로

이기호,정승기,김혜진,이인성,김진우,Lee, Ki-Ho,Jung, Seung-Ki,Kim, Hye-Jin,Lee, In-Seong,Kim, Jin-Woo 대한인간공학회 2007 大韓人間工學會誌 Vol.26 No.3

Digital convergence, defined as the creative fusion of once-independent technologies and service, is getting more attention recently. Interruptions among internal functions happen frequently in digital convergence products because many functions that were in separate products are merged into a single product. Multi-tasking and multi-modality are two distinctive features of interruption in digital convergence products, but their impacts to the user have not been investigated yet. This study conducted a controlled experiment to investigate the impacts of multi-tasking and multi-modality on the subjective satisfaction and objective performance of digital convergent products. The study results indicate that multi-tasking and multi-modality have substantial effects individually as well as together. The paper ends with practical and theoretical implications of study results as well as research limits and future research.

Clinical Efficacy of Latex Cover for Dental Handpiece

이기호,백동헌,Lee, Ki-Ho,Paek, Dong-Heon Korean Academy of Orofacial Pain and Oral Medicine 2009 Journal of Oral Medicine and Pain Vol.34 No.3

The purpose of this study was to investigate the clinical efficacy of latex cover developed for dental handpiece on contamination of microorganisms during dental treatment and to determine whether it can be an alternative to conventional sterilization such as autoclaving. E. fecaelis was used as a experimental microorganism instead of oral flora. Experimental bowl with 2 cm of rectangular cavity was fabricated for handpiece operating instead of oral cavity. Latex covers ($Orokeeper^{(R)}$, Orobiotech Co., Korea) and several handpieces were used after sterilization by autoclave. Four experiments were performed to evaluate bacterial contamination related with (1) various parts of dental handpiece, (2) swabbing time with alcohol sponge, (3) postoperative air-water spraying time and (4) consecutive use of latex covers without autoclaving. The results show that face of handpiece uncovered with latex cover was severely contaminated than the covered area and that most bacteria were removed by swabbing face and head area of dental hand-piece and by air-water spraying more than 15 seconds nearly up to the level of sterilization. Conclusively it can be suggested that use of latex cover for handpiece during dental procedure, swabbing with alcohol sponge is air-water spraying for more than 15 seconds after use of dental handpiece should be very useful and practical for prevention of cross infection and should be an alternative method for the sterilization of dental handpiece under some difficult situations not being able to sterilize a handpiece with autoclave.

제주시 도로변에서의 에어로졸의 입경별 분포 특성

이기호,김수미,허철구,Lee, Ki-Ho,Kim, Su-Mi,Hu, Chul-Goo 한국환경과학회 2021 한국환경과학회지 Vol.30 No.9

Measurements on mass size distribution of roadside aerosols were obtained in downtown Jeju City from July 2018 to May 2020 using an 8-stage cascade impactor sampler and the compositions of aerosols were analyzed. The mass size distribution of total aerosols was bimodal with aerosols existing in both the fine and coarse modes. The mass size distributions of Na⁺, Mg²⁺, Ca²⁺, Cl^-, NH₄⁺ and SO₄^2- were unimodal, whereas that of K⁺ was bimodal. For NO₃^-, the size distribution in winter and spring was bimodal with the peaks in both fine and coarse modes, whereas for summer and autumn the distribution was unimodal with a peak in the coarse mode. NH₄⁺ was found to co-exist with SO₄^2- in the fine mode with an average molar ratio of [NH₄⁺]/[SO₄^2-] equal to 2.05. Good correlation was observed between NO₃^- and NH₄⁺ in the fine mode particles in spring and winter. Based on the value of the marine enrichment factor for Cl^-, Mg²⁺, K⁺, Ca²⁺ and SO₄^2-, it may be inferred that a major part of the roadside aerosols in downtown Jeju City was largely contributed by terrigenous sources, although the influence of sea salt was normally present.

제주시 지역 미세먼지의 변동과 화학적 구성 특성

이기호,김수미,김길성,허철구,Lee, Ki-Ho,Kim, Su-Mi,Kim, Kil-Seong,Hu, Chul-Goo 한국환경과학회 2020 한국환경과학회지 Vol.29 No.5

This study investigated the nitrate formation process, and mass closure of Particulate Matter (PM) were calculated over the urbanized area of Jeju Island. The data for eight water-soluble inorganic ions and nineteen elements in PM_2.5 and PM₁₀ were used. The results show that the nitrate concentration increased as excess ammonium increased in ammonium-rich samples. Furthermore, nitrate formation was not as important in ammonium-poor samples as it was in previous studies. According to the sum of the measured species, approximately 45~53% of gravimetric mass of PM remained unidentified. To calculate the mass closure for both PM_2.5 and PM₁₀, PM chemical components were categorized into secondary inorganic aerosol, crustal matter, sea salt, trace matter and unidentified matter. The results by the mass reconstruction of PM components show that the portion of unidentified matter was decreased from 52.7% to 44.0% in PM_2.5 and from 45.1% to 29.1% in PM₁₀, despite the exclusion of organic matter and elemental carbon.

Application of Synchrotron Radiaton to Semiconductor Process and Surface Photochemical Reaction

이기호,김병엽,이시우,Lee, Ki-Ho,Kim, Byoung-Youp,Rhee, Shi-Woo 한국진공학회 1995 Applied Science and Convergence Technology Vol.4 No.s1

인체 멜라닌 세포의 배양에 관한 연구

이기호(Ki Ho Lee),이무형(Mu Hyoung Lee),박재경(Jai Kyung Park),허충림(Choong Rim Haw) 대한피부과학회 1990 대한피부과학회지 Vol.28 No.2

The author evaluated the optimal concentration of 3 compositions of TIC medium which has used as the melanacytes culture medium. The concentrations of placental extract and bovine pituitary extract, which have the ability to promote proliferation of melanocytes, were evaluated also. Modified TIC medium with above 5 components of evaluated concentration was very effective in melanocytes culture. The results were as follows : l. 12-0-tetradecanoyl-phorbol-13-acetate (TPA) showed effective melanocytes proliferating activity at the concentration of 30ngml (p(0.05) 2. Isobutylmet:hyl xanthine (IBMX) showed effective melanocytes proliferating activity at the concentration of 0.3mM (p(0.05) 3. Cholera toxin (CT) showed effective melanocytes proliferating activity at the concentration of )OnM (p(0.05) 4. Two percentages of placental extract in culture medium showed effective melanocytes proliferating activity. S. Two percentages of bovine pituitary extract in culture medium showed effective melanocytes proliferating activity. 6. Placental extract and isobutylmethyl xanthine proved to have high melanocytes proliferating activity. 7. Melanocytes proliferated rapidly on modified TIC medium (Proliferation doubling time . about 43 hours) 8. The peak time of melanocytes proliferation (7.2 X 10/cm) was observed on the seventh day of culture, From this data, this culture system can be recommended as a new melanocytes culture. (Kor J Dermatoi 28<2): 136 146, 1990)

Stationary and Moving Computed Radiography Grids : Comparative Observer's Perception

이기호(Ki ho Lee),이창훈(Chang hoon Lee),진계환(Gye hwan Jin) 한국방사선학회 2015 한국방사선학회 논문지 Vol.9 No.7

고정형 그리드(stationary grid)에서 그리드 아티팩트(grid artifacts)와 모아레 아티팩트(moiré pattern artifacts)로 인한 영상의 질의 저하와 이동형 그리드(moving grid)에서의 컷 오프 아티팩트(cut off artifacts)로 인한 영상의 질의 저하를 정량적으로 비교 평가하였다. CDRAD 팬텀(Phantom)과 두께 24 cm의 acryl Phantom을 촬영조건(X-ray exposure conditions)을 100 cm, 80 kVp, 30 mA로 하여 고정형 그리드와 이동형그리드에서 영상(X-ray imaging)을 획득하였다. CDRAD Analyser을 이용한 영상(X-ray imaging) 인식률(observer's perception)은 고정그리드에서 평균(mean) 49.36, 표준편차(standard deviation) 3.76, 최대값(max) 55.56, 최소값 38.67이었고 이동형그리드에서 평균 47.04, 편차 12.69, 최대값 55.56, 최소값 20.89이었다. 이동형 그리드보다 고정형 그리드가 인식률의 평균과 표준편차에서 더 우수하게 나타났다. This study assessed the degradation of image quality caused by grid artifacts and moiré pattern artifacts in a stationary grid, and the degradation of image quality caused by cut off artifacts in a moving grid. X-ray images were acquired in a stationary grid and a moving grid with X-ray exposure conditions of 100 cm, 80 kVp, and 30 mA using a CDRAD phantom and a 24-cm-thickness acrylic phantom. Observer's perception of X-ray imaging using CDRAD Analyzer was mean 49.36, standard deviation 3.76, maximum 55.56, and minimum 38.67 in the stationary grid, and 47.04, 12.69, 55.56, and 20.89, respectively, in the moving grid. The stationary grid was superior to the moving grid in terms of the mean and standard deviation of observer's perception.

굴패각 혼합토의 압밀 및 투수특성

이기호(Lee Ki-Ho),한종옥(Han Jong-Ok) 대한토목학회 2001 대한토목학회논문집 C Vol.21 No.4

전자코에 의한 방향성 심비디움 ‘환희’의 화기조직, 포집 시간 및 개화시기별 분석

이기호(Ki Ho Lee),박부희(Pue Hee Park),예병우(Byeong Woo Yae),이영란(Young-Ran Lee),박필만(Pil Man Park) 한국원예학회 2012 한국원예학회 학술발표요지 Vol.2012 No.10