한국 정상인에서 연령에 따른 뇌혈류분포와 혈류예비능의 변화 : Tc-99m HMPAO SPECT 에 의한 연구

문대혁,이희경,송호천,이재태,범희승,손혜경,정환정,민정준,김지열 대한핵의학회 1999 핵의학 분자영상 Vol.33 No.3

Purpose: The aim of this study was to evaluate the normal values of regional cerebral blood flow (rCBF) and cerebrovascular reserve (CVR) in normal children to aged volunteers using Tc-99m HMPAO. Materials and Methods: Thirty four right-handed normal volunteers (20 males, 14 females, mean age 40.3±24.9 years, range 4 to 82 years) were underwent rest/acetazolamide (ACZ) brain SPECT using Tc-99m HMPAO and the sequential injection and subtraction method. rCBF was estimated on the basis of a semiquantitative approach by means of right/left ratio, region/cerebellum and region to whole brain ratios in frontal, parietal, temporal, and occipital lobes, basal ganglia, thalami, and cerebellum. CVR was measured by means of % perfusion increase calculated as % mean count change compared to rest rCBF in each regions. Results: Mean values of right to left ratios range from 1.004 to 1.018. rCBF was highest in cerebellum and lowest in basal ganglia and thalami. Frontal and temporal rCBF decreased while occipital and thalami rCBF increased according to age. No sexual difference of rCBF was noted. Mean CVR was 29.9±12.9%. Mean CVR significantly increased to late teens, and declined thereafter. After 6th decade, CVR in both frontal lobes, left parietal lobe and right basal ganglia decreased significantly with advancing age. There was no sexual difference of CVR. Conclusion: Quantitative assessment of CVR was possible by ACZ Tc-99m HMPAO brain SPECT. It revealed that rCBF and CVR changed according to age in normal Korean volunteers. There was no sexual difference.

2 - 아미노나프탈렌술폰산류의 자외선분광 광도법에 의한 분석

Sohn Joo Hwan(孫周煥),Kim Joo Youn(金宙元) 한국유화학회 1986 한국응용과학기술학회지 Vol.3 No.2

The sulfuric acid sulfonation mixtures of 2-aminonaphthalene, contained 2-aminonaphthalene, Dahl s acid, Broenner s acid, amino-F-acid and Baden acid, can be determined quantitatively by multicomponent spectrophotometric analysis. The analysis was performed in diluted sodium hydroxide aqueous solution and based on the ultraviolet absorption of the sodium salts of each isomers. The determination of quantity of each isomers was performed by subjection the absorbances of the unknown mixture and of its constituents, gathered at a large number of wavelengths, to a least square treatment by an electronic personer computer. This method provided a rapid analysis of such complex mixture, and the standard deviation was ±1.65 mole %.

Effect of cyclic AMP on volume-activated KCl cotransport

Sohn, Dong Hwan 圓光大學校 藥品硏究所 1992 藥品硏究所報 Vol.7 No.1

적혈구가 저장액에 노출시 팽창된 부피를 원래의 부피로 조절시 사용되는 KCl cotransporter의 신호 전달 기전 연구의 일환으로 cAMP에 대한 영향을 살펴 보았다. 저장액에서는 세포가 swelling이 되고 K^+이온의 이동을 증가시켰다. cAMP의 증가는 KCl cotransporter에 의해 전달되는 K^+이온의 이동을 촉진시켰다. cAMP값이 최저 0.3ng/g·Hb에서 1.5∼4.0ng/g·Hb 으로 증가시 KCl contransport 는 최대치를 나타냈다. Kinetic자료에 의하면 cAMP activation으로 K^+이온에 대한 Km이나 Vmax가 3배 이상 증가시켰다. 또한 swelling이나 cAMP에 의한 KCl cotransport는 pH, Ca^2+그리고 ATP농도와 연관되었다. 1μmol/ml이하의 ATP나 10^-6M이상의 pCa에서는 KCl cotransport는 활성화되지 않았다. KCl cotransporter활성화는 pH7.1∼7.4에서 일어났다. 이상의 결과로부터 돼지 적혈구의 KCl cotransporter는 cAMP에 의해 조절받고 있음을 관찰하였다.

Device and Piezoelectric Characteristics of Pb(Mn1/3Sb2/3) O3-PZT Ceramics for Piezoelectric Transformer

Sohn, Joon-Ho,Heo, Soo-Jeong,Sohn, Jeong-Ho,Lee, Joon-Hyung,Jung, Woo-Hwan,Kim, Dong-Bum,Cho, Sang-Hee The Korean Ceramic Society 1999 The Korean journal of ceramics Vol.5 No.2

In the $(Pb_{1-x}M_x)[(Mn_{1/3}Sb_{2/3})_{0.05}Zr_yTi_{0.95-y}]O_3$ system, where M=Ca and Sr, the piezoelectric properties were evaluated to examine the possibility of application to piezoelectric transformer. A Rosen-type piezoelectric transformer was formed, then the electrical properties of voltage step-up ratio, frequency characteristics etc. were analysed. The morphotropic phase boundary was determined to be y=0.475 in $Pb[(Mn_{1/3}Sb_{2/3})_{0.05}Zr_yTi_{0.95-y}]O_3$ system and the piezoelectric properties of this composition was kp=0.59, Qm=1600 and $\varepsilon_r$=1150. Moreover, when 1-2 mol% of Sr are substituted, enhanced piezoelectric properties of kp=0.61, Qm=1600 and $\varepsilon_r$=1400 were shown. The temperature rising (ΔT) of a piezoelectric transformer with $Pb[Mn_{1/3}Sb_{2/3})_{0.05}Zr_{0.475}Ti_{0.475})]O_3 $ composition was $10^{\circ}C$, and the voltage step-up ratio was 500 when the output voltage was 4000V, whereas the ΔT was below $3^{\circ}C$ and the resonant frequency variation ($\Delta f_r$) as a function of load resistance was below 5% when the output voltage was 2000 V. These characteristics are superior to the properties of materials, which were substituted by Ca or without substitution.

An Examination of an IT Turnover Model in IT Service Settings

Sohn, Yoon Hwan(손윤환),Lee, Eun Young(이은영),Lee, Myeong Ju(이명주),Cho, Bongsoon(조봉순) 한국서비스경영학회 2018 서비스경영학회지 Vol.19 No.5

The objective of this study is to explore the mechanism behind turnover among IT service professionals. The current study investigated employee turnover by verifying and extending the IT turnover model in IT service setting and suggested possible factors. A Korean IT service company was selected for examination. Exit interview data collected for 6.5 years were used for research purposes(n=81). The results suggested that the model was a viable guideline to investigate IT service turnover. More specifically, pay and demographic factors including gender, education, organizational tenure were viable predictor for turnover of IT service professional. Also we found factors on related to organizational support, i.e., communication, recognition and relational support were important predictors for turnover in IT professionals which were not included in the model.

Control of Delta-Wing Vortex by Micro-Fin-Type Leading-Edge Flap

Sohn, Myong-Hwan,Chung, Hyoung-Seog,Cho, Dong-Hyun The Korean Society for Aeronautical and Space Scie 2006 International Journal of Aeronautical and Space Sc Vol.7 No.2

The present study examined the effects of micro leading-edge flaps on the vortex characteristic changes of a double-delta wing through pressure measurements of the wing upper surface and PIV measurements of the wing-leeward flow region. The experimental data were collected and analyzed while changing the deflection angle of the leading-edge flaps to investigate the feasibility of using micro leading-edge flaps as flow control devices. The test results revealed that the leading edge modification could greatly alter the vortex flow pattern and the wing surface pressure of the delta wing, which suggested that the leading-edge flaps could be used as an effective device for the control of delta-wing vortex flow.

Control of Delta-Wing Vortex by Apex Strake

Sohn, Myong-Hwan,Chung, Hyoung-Seog The Korean Society for Aeronautical and Space Scie 2007 International Journal of Aeronautical and Space Sc Vol.8 No.2

The vortex flow characteristics of a double-delta wing, which can change the incidence angle of its apex strake was investigated through the wing-surface pressure measurement and the particle image velocimetry(PIV) measurement of the wing-leeward flow region. The apex strake has sharp edges and can change its incidence angle with a hinge line at the 23% chord position measured from the apex of the main wing. The present study revealed that the incidence-angle change of the apex strake could greatly alter the vortex flow pattern around the double-delta wing and the wing-surface pressure distribution, which suggested that the apex strake could be used as an effective device for the active control of delta-wing vortex flow.

Morphologic changes of Ti surface by surface modification

Sohn, Dong-Hwan 경북대학교 생체재료연구소 1999 생체재료연구소보 Vol.2 No.-

A Nationwide Study of Surgery in a Newly Diagnosed Spine Metastasis Population

Sohn, Seil,Chung, Chun Kee,Han, Kyung Do,Jung, Jin Hyung,Hyeun, Joung Ho,Kim, Jinhee,Chang, Ung-Kyu,Sohn, Moon Jun,Kim, Sung Hwan The Korean Neurosurgical Society 2019 Journal of Korean neurosurgical society Vol.62 No.1

Objective : The aim of this nationwide study was to analyze the current state of patients with newly diagnosed metastatic spine tumors according to surgical methods. Methods : Data was extracted from the Korean Health Insurance Review and Assessment Service database. Surgery was categorized into three methods : fusion, decompression, and vertebroplasty. Data included patient age, sex, health insurance type, and co-morbidities. Survival rates of metastatic spine tumor patients according to each surgical method were evaluated. Results : Among 1677 patients who had an operation, 823 patients were treated by fusion, 141 patients underwent decompression, and 713 patients were treated by vertebroplasty. The three most prevalent primary tumor sites were the lung, breast, and liver & biliary. On the other hand, the three most prevalent primary tumor sites of patients who underwent surgery were the lung, liver & biliary, and the prostate. The median survival periods for each surgical method in the metastatic spine tumor patients were 228 days for those who underwent surgery, 249 days for decompression, and 154 days for vertebroplasty. Age, sex, and comorbidities significantly affected survival rate. Conclusion : For every primary tumor site, decompression was the least common surgical method during the study period. Although the three surgical methods did not significantly affect the survival period, patients with a poor prognosis tended to undergo vertebroplasty.

Stereotactic radiosurgery compared with external radiation therapy as a primary treatment in spine metastasis from renal cell carcinoma: a multicenter, matched-pair study.

Sohn, Seil,Chung, Chun Kee,Sohn, Moon Jun,Chang, Ung-Kyu,Kim, Sung Hwan,Kim, Jinhee,Park, Eunjung M. Nijhoff ; Kluwer Academic Publishers 2014 Journal of neuro-oncology Vol.119 No.1

<P>The aim of this multicenter, matched- pair study was to compare the outcome of stereotactic radiosurgery (SRS) with that of external radiation therapy (RT) when used as a primary treatment in spine metastasis from renal cell carcinoma (RCC). From 2005 to 2012, 13 patients underwent SRS as a primary treatment in spine metastasis from RCC. Thirteen patients who underwent RT as the primary treatment of RCC spine metastasis were paired with the SRS patients based on age, number of spine metastasis, time interval from original tumor diagnosis to spine metastasis, Eastern Cooperative Oncology Group status, and year of treatment. The primary outcomes of interest were pain relief and progression free survival. Secondary outcomes were treatment toxicities and need for further treatment. The perioperative VAS score decrease was larger in the SRS group than that in the RT group (P = 0.04). More SRS patients had complete or partial pain relief although the difference was not significant. There was a significant difference in progression free survival between the two groups (P = 0.01). The percentage of patients with toxicities was 38.5 % (5/13) in the SRS group and 53.9 % (7/13) in the RT group, but the difference was not significant. There were 2 SRS patients and 3 RT patients who received further intervention at the index segment. This study showed that, when performed as a primary treatment in spine metastasis from RCC, SRS provides relatively better pain relief and better local control than that obtained from RT.</P>