뇌신경질환 고자장 자기공명영상

서형석 대한의사협회 2010 대한의사협회지 Vol.53 No.12

The primary merit of a 3 tesla (T) magnetic resonance (MR) scanner is the increase in the signal-to-noise ratio (SNR). It can offer high spatial and temporal image resolution and its diagnostic potential for brain lesions can be improved at the magnetic strength of 3T. In addition to the increased SNR, strong prolongation of T1 relaxation time at high field MR leads to overall improvements in enhancing lesions versus non-enhancing tissue on contrast-enhanced T1-weighted images and blood versus tissue contrast on time-of-flight MR angiography. Increased chemical shift and susceptibility can improve the spectral resolution in MR spectroscopy and the sensitivities in the micro-hemorrhage detection of gradient echo image, the perfusion change of perfusion MRI, and the blood oxygen level-dependent effect of functional magnetic resonance imaging (MRI). The short acquisition time of diffusion MRI at 3T can decrease motion artifacts in irritable stroke patients and it can be easier to estimate anisotrophy and to increase the efficiency of tractography in diffusion tensor imaging with high numbers of gradient directions. On the other hand, the regulation of the specific absorption rate due to increased radio-frequency energy deposition and the controls for signal loss and increased artifacts at 3T are the main clinical problems. If the drawbacks can be addressed by parallel imaging or pulse sequence changes,3T MRI can be a useful diagnostic tool and increase the diagnostic accuracy in various brain lesions, such as stroke, trauma, epilepsy, multiple sclerosis, dementia, and brain tumors.

남성 가성 반음양 1例

서형석,박영호 順天鄕大學 1987 순천향대학논문집 Vol.10 No.1

기능성 자성입자를 이용할 토양의 유동성 카드뮴 분석

서형석,나인욱,황경엽,신현철,김범석,유영석,So Hyungsuk,Nah In-Wook,Hwang Kyung-Yub,Shin Hyun Chul,Kim Beom-Suk,Yoo Yeong-Seok 한국지하수토양환경학회 2005 지하수토양환경 Vol.10 No.1

Potential for measuring mobile cadmium concentration in sandy soil using polymer magnetic beads with carboxyl groups was investigated. Experiments for extracting cadmium were performed with contaminated soils, de-ionized water and magnetic beads. In this neutral experimental condition, reacting cadmium with magnetic beads indicate total amount of cadmium that can be moved in soil. The results showed that the mobile fraction of cadmium in soil could be combined with magnetic beads in short time. After binding between cadmium and magnetic beads, the beads were separated from soil suspension by outer magnetic force. The bound cadmium was dissolved from magnetic beads by acid solutions, which were then analyzed by atomic absorption spectroscopy (AAS). This method can determine mobile heavy metals in sandy soil effectively than existing method which use pollutant chemicals to environments such as EDTA. 카르복실기가 결합된 고분자 자성체 (Magnetic beads)를 이용하여 토양에 함유되어 있는 유동성 카드뮴의 분석 가능성을 알아보았다. 추출실험은 채취된 오염토양을 통하여 행하여 졌는데, 추출실험재료로는 단지 토양시료, 증류수 그리고 고분자 자성체만이 사용되었다. pH가 중성인 이 조건에서 자성체는 토양에서 이동성이 있는 카드뮴만을 추출하게 되는데, 이런 토양의 유동성 카드뮴이 교반을 통하여 빠르게 고분자 자성체와 결합하는 것을 알아냈다. 그 후 자성체는 외부 자력으로 모아져 산으로 용해되고, 자성체에 결합되어 있던 카드뮴 다시 용출되어 Graphite furnace 원자흡광기 (AAS)로 분석되었다. 3가지 모래성토양의 추출실험결과를 보면 토양의 유동성 중금속 농도를 분석할 때 전형적으로 사용하는 EDTA (Ethylendiamintetraacetic acid)와 비교할 때, 고분자 자성체를 이용한 효율이 비슷하거나 더 높았음을 알 수 있었다. 이로서 모래성토양에서 유동성 중금속 농도를 분석할 때, 난분해성 물질인 EDTA등을 사용하지 않고 더 정확하고 간단히 유동성 카드뮴의 분석실험을 수행할 수 있음을 보여주었다.

한국인에서 흡연이 방광암에 미치는 영향에 관한 전향적 Cohort 연구

서형석,이남규,지선하 대한비뇨의학회 2005 Investigative and Clinical Urology Vol.46 No.3

Purpose: To verify the association between cigarette smoking and bladder cancer in the Korean population, as smoking is well known as a risk factor on bladder cancer. The risk of bladder cancer was compared among never- smokers, ex-smokers and current-smokers using a multivariate adjusted incidence rate and the mortality rate of bladder cancer of Koreans. Materials and Methods: A total of 348,010 participants were enrolled in this prospective study between 1993(to 1994) and 2002. All participants completed a self administered questionnaire on cancer risk factors, including smoking habit. Follow up for incident bladder cancer was established. We classified all participants into three categories: current-smoker, ex- smoker and never-smoker, on the basis of their smoking habits. We confirmed bladder cancer from the data of the Korea National Cancer Registry and National Health Insurance Corporation up to(December?) 2002. The multivariate adjusted incidence and the mortality due to bladder cancer were used for both genders for a statistical analysis using a Cox proportional hazards model. Results: The incidence rate of bladder cancer per 100,000 persons in male never-smokers, ex-smokers and current-smokers were 27, 41 and 48, respectively, and the multivariate adjusted relative risks (RR) were 1.3 (95% confidence interval(CI), 0.9-2.0) and 1.7(95% CI, 1.2-2.3) in ex- and current smokers, respectively. The incidence rate of bladder cancer in women was 4.7, 8.4 and 13, respectively. There was no significant association between the risk of bladder cancer and the amount and duration of smoking. Conclusions: We concluded that current smokers have an increased incidence and mortality rate of bladder cancer in both genders in the Korean population, but there was no significant difference in relation to the amount and duration of smoking 이 연구는 한국인 대규모 인구집단을 장기간 추적한 전향적 코호트연구방법을 통해, 흡연 여부가 방광암발생에 미치는 영향을 파악하고자 실시한 역학연구이다. 남여 공히 비 흡연자에 비하여 현재 흡연자의 경우 방광암 발생은 남자는 1.7배, 여자는 1.6배 높았으며, 방광암으로 인한 사망은 남자 1.7배, 여자 2.3배 높은 것으로 나타났다. 외국의 경우 이미 흡연과 방광암에 대한 연구가 많이 보고되어 있으나, 흡연율이 매우 높은 우리나라에서 흡연이 방광암을 유발하는 확실한 위험인자로 확인되었기에 적극적인 예방과 대처가 필요할 것으로 생각하며 향후 좀더 정확하고 객관적인 연구가 필요할 것으로 생각한다.

2차원 공동의 형상 변화에 의한 공기-연료 혼합 성능의 수치적 해석 연구

서형석,전영진,정희,변영환,이재우 한국항공우주학회 2007 한국항공우주학회 학술발표회 논문집 Vol.- No.-

2차원 공동의 종횡비 변화에 대한 공기-연료 혼합 성능의 수치적 해석

서형석,김기수,전영진,변영환,이재우 한국항공우주학회 2007 한국항공우주학회 학술발표회 논문집 Vol.- No.-

새로운 Smart Fashion Item HandkerPlay 신기술창업계획서

서형석,김진현,안지은 한국창업학회 2013 한국창업학회 Conferences Vol.2013 No.3

특집:그린홈에서의 실내환경 개선기술 - 삼성의 Green Tomorrow 사례 및 실내환경 관련 적용기술

서형석,Seo, Hyeong-Seok 한국공기청정협회 2010 空氣淸淨技術 Vol.23 No.1

복합소재를 적용한 하이브리드 유압 실린더의 구조강도 연구

서형석,장호윤,박희승 해양환경안전학회 2018 해양환경안전학회 학술발표대회 논문집 Vol.2018 No.11

Change in the effect of rocuronium after pneumatic tourniquet release in patients undergoing unilateral total knee arthroplasty

서형석,고원욱,백재원,노영진,양홍석 대한마취통증의학회 2015 Anesthesia and pain medicine Vol.10 No.1

Background: A pneumatic tourniquet is commonly used inorthopedic surgery. However, neuromuscular blocking agent can besequestered in the isolated limb and be reabsorbed into the systemiccirculation after tourniquet release, potentially delaying extubation. To investigate the change in the train-of-four (TOF) ratio aftertourniquet release and correlate the TOF ratio change with theextubation time. Methods: Forty patients undergoing unilateral total kneearthroplasty were enrolled. Before and after the pneumatictourniquet release, 10 measurements of the TOF ratio wereaveraged and compared. Additionally, we investigated thecorrelation between the percentage change in the TOF ratio beforeand after tourniquet release and the extubation time. Results: Among the 40 patient subjects, 30 showed a TOF ratiobefore tourniquet release and 10 showed only a TOF count. Of the30 patients with a TOF ratio, 21 showed a TOF ratio increase aftertourniquet release and 9 showed a TOF decrease; both increaseand decrease were statistically significant (P < 0.001 and P = 0.008,respectively). The extubation time showed a weak negativecorrelation with the percentage change in the TOF ratio aftertourniquet release (P = 0.004). Conclusions: In orthopedic surgery using a pneumatic tourniquet,neuromuscular function monitoring may be required to monitor thechange in the effect of neuromuscular blocking agent before andafter tourniquet release, which may help to improve anesthesiasafety.