전기유동유체의 전기적 내구성에 대한 실험적 고찰

박우철,이현창,이형식 三陟大學校 2001 論文集 Vol.34 No.1

This paper presents experimental results on material properties of an electro-rheological(ER) fluids subjected to electrical fatigues. As a first step, two types of ER fluids made of arabic gum and methy1 cellulose(MC) choosing 25% of particle weight-concentration. Following the construction of test mechanism for electrical durability of ER fluid, the dynamic yield shear stress and current density of the ER fluids are experimentally distilled as a function of electric field. The yield shear stress of operated ER fluids are distilled and compared with those of unused ER fluids. In addition, the surface roughness of the employed electrode are evaluated as a function of the number of the electric-field cycle.

足三里의 電鍼刺戟이 흰쥐의 中樞神經系에서 Interleukin-6의 活性에 미치는 影響 - 求心性 體感覺 情報傳達을 中心으로- : 求心性 體感覺 情保傳達을 중심으로

이혜정,신형철,진수희,손양선,윤동학,임사비나 경희대학교 동서의학연구소 2001 東西醫學硏究所 論文集 Vol.2000 No.-

Objectives : Acupuncture is expected to have somewhat like the efficacy parallel increasing activity of immune system in Western modern medicine. There, already, are many animal researches on activating effect of acupuncture for the immune system in peripheral organs. So, we carried out this experiment to see whether acupuncture has controlling effect on interleukin-6(IL-6) activity in rat's brain. Methods and Results : We had topical application of IL-6(1U-1pg, 10㎕) on brain of rat. It reduced afferent sensory transmission to the primary somatosensory(SI) cortex from periphery. Whereas, electrical stimulation(ES, 2Hz, 1.5V, 15min) of ST36(足三里) with application of IL-6 prominently activated afferent sensory transmission. ES of non-acupoint(proximal tail) with IL-6 showed suppression of afferent transmission. ES of ST36 without IL-6 application also exerted facilitation of afferent transmission to the SI cortex. Conclusions : Electoacupuncture(EA) on ST36 has noticeable influences on modulating activation of IL-6 in central nervous system, which do major role in immune system.

저산소성 허혈성 뇌증 후 발생한 피질맹에 관한 임상적 고찰

윤영옥,최형철,오광수 圓光大學校 醫科學硏究所 1996 圓光醫科學 Vol.12 No.2

Cortical blindness is defined as bilateral absence of vision caused by cerebral disease and is characterized by the retention of the pupillary responses and the absence of optic atrophy. The causes are multiple and include infection, trauma, cerebrovascular disease, toxins, hypoxia, degenerative diseases, congenital aberrations, and vasculitis. Thrombosis, embolization, and selective laminar cortical necrosis due to cerebral anoxia are possible mechanisms. We experienced a case of cortical blindness in a 6 month-old boy who had suffered from seizure and semicomatous mental status after milk choking. On 9th hospital day, mother of this patient noticed that her son had no visual regard and blinking movement. Brain MRI showed diffuse obliteration of white and gray matter differentiation in both parieto-occipital lobe in T1 weighted image and diffuse T2 hypointense lesion on the corresponding area suggesting diffuse hypoxic ischemic injury. Visual evoked potential revealed no response to flash. We report this case with a brief review of the related literatures.

컴퓨터과학 교육을 중심으로 한 중등 컴퓨팅 교육과정 설계

신상국,권대용,김형신,염용철,유승욱,이원규 한국컴퓨터교육학회 2005 컴퓨터교육학회 논문지 Vol.8 No.3

객체지향형 교육용프로그래밍언어 두리틀의 다중 예약어 지원 체계

최해심,권대용,김형신,염용철,유승욱,이원규 한국컴퓨터교육학회 2005 컴퓨터교육학회 논문지 Vol.8 No.2

In Vitro 고삼투압이 정자 원형질막의 Protein Tyrosine Phosphorylation에 미치는 영향

오영근,장재호,최인호,정노팔,신형철,곽병주 대한의생명과학회 2000 Journal of biomedical laboratory sciences Vol.6 No.4

정자의 원형질막은 삼투압에 의해서 영향을 받는다고 보고되고 있다. 이중 세포막내 분자구조의 변화 특히 막지질 구조의 변화와 동반되는 이온채널의 변화 그리고 Ca2+과 HCO-3의 유동성과도 밀접한 관련이 있는 것으로 보고되고 있다. 지금까지의 연구보고에 의하면, 정자의 첨체반응 (acrosome reaction)이 일어날 경우 protein tyrosine phosphorylation이 증가되는데 이것은 cAMP, protein kinase A 등을 통하여 작용되는 것으로 보고되고 있다. 막의 지질변화를 유도하는 물질로 일종의 sterol acceptor인 BSA가 알려져 있는 바, 실제로 BSA가 막지질 성분에 미치는 영향을 관찰한 결과 cholesterol이 유출되고 이온 등의 유동성 변화가 일어나, 이 유동성 변화가 정자의 adenylyl cyclase를 활성화시켜 cAMP를 증가시키고, PKA가 활성화되어 결과적으로 Protein tyosine phosphorycation이 유도된다고 보는 것이다. 침체반응과 protein tyrosine phosphorylation과는 밀접한 관계가 있는 것으로 사료되고 있다. 본 연구는 정자 원형질막에서 cholesterol이 유출되어 protein tyrosine phosphorylation이 유도될 때, BSA와 같은 sterol acceptor가 작용할 것이라는 전제하에, 고삼투압 하에서 탈수로 인해 원형질막이 위축되더라도 sterol acceptor가 존재한다면 막지질 성분의 구조적 변화가 억제 될 수 있을 것이라는 가설을 설정하였다. 실험결과, 저온 및 고삼투압 하에서 정자운동은 감소되지만 원형질막의 구조적 변화는 없고, 삼투압에 대한 반응정도는 원형질막을 통한 수분이동과 세포용적 변화에 따라 비례적으로 일어난다고 하는 사실을 발견하였다. 이 결과는 정자보존에 있어서 저온변화에 영향을 미치는 여러 인자들 특히 protein fgrosine phosphorylation의 증가와 밀접한 관계가 있음을 시시해 준다. 또한 sterol acceptor로 알려진 BSA는 삼투압이 변화되더라도 역시 중요한 인자로 작용할 수 있음을 알 수 있었으며, 특히 고삼투압으로의 변화는 cAMP와 protein kiname A를 거치는 신호전달과정에 있어서 중요한 요인이라는 사실을 확인할 수 있었다. It has been reported that plasma membrane activity of the spermatozoa may be susceptible to be influenced by extracellular osmolality and such membranous changes involve intracellular molecular changes, special regard to the structure of membranous lipids, and the accompanying ion-channel of which are closely related with their fluidity of Ca2+ and HCO-3. It is of common recognition that a certain kind of sterol acceptor player an important to induce lipid fluctuation of the sperm plasma membrane which have been influenced by BSA administration and came in effect to outflow of cholesterol from the spermatozoa and resulted in changes of ionic fluidity to facilitate adenylyl cyclase, and to induce protein tyrosine phosphorylation by increase of cAMP and activation of PKA. Thus it seems likely that an augmentation of the acrosomal reaction is closely related with protein tyrosine phosphorylation. The following experimental results were obtained in the present study; Under the high osmolality conditions, the spermatozoa motility declined significantly and the structural change of the plasma membrane diminished to confirm that the response degrees to the osmolality depended upon the water transfer volume through the plasma membrane and the changes of cellular volume. Those experimental results suggest that a physiological parameter such as low temperature condition played an important role for presentation of spermatozoa and that inducement of spermatozoa activation for reinforcement of protein tyrosine phosphorylation. On the other hand, it seemed likely that the BSA administration as one of sterol acceptors might represent a key role also under the high osmolality condition and their result also suggests that osmolality change, special regard to high osmolality condition may play an important role also in the processes of signal transmission

결절성 및 괴상성 간세포암에서 역동적 전산화단층촬영 소견에 따른 경동맥화학색전술결과의 예측

이성문,김홍,지성우,우성구,이정형,서수지,손철호 啓明大學校 醫科大學 1997 계명의대학술지 Vol.16 No.2

Purpose: To evaluate retrospectively whether it is possible to predict the transarterial chemoembolization(TACE) result with the pre-TACE dynamic CT findings. Materials and Methods: The dynamic CT findings of 33 patients with 35 nodular and 8 massive hepatocellular carcinoma(HCCs) who was taken follow up CT after TACE, were reviewed retrospectively. After excluding the diffuse or infiltrative HCCs, the mass was classified into two groups of nodular and massive types. The size, location, degree of enhancement, pseudocapsule, portal vein(PV) thrombosis and arterioportal(AP) shunt were evaluated on the dynamic CT scans. The vascularity, multiple or parasitic blood supply, AP shunt and the possibility of superselection were considered on the angiography. After TACE, the pattern of lipiodol uptake and residual enhancing nodules were evaluated on the follow-up CT scans. Results: The good TACE results could be obtained in 18 of 35 nodular HCCs with dynamic CT findings of small size(mean=2.94cm), peripheral location, hyper-or iso-enhancement, and absence fo PV thrombosis, with angiographic finding of possible superselection, but the pseudocapsule did not give important effect on the result. Most of the massive HCCs had poor TACE results. Conclusion: The prediction of the TACE results of nodular and massive HCCs was possible with dynamic CT findings. If the good prognostic factors were not observed on the pre-TACE dynamic CT, the multiple TACE and/or combination therapy with percutaneous ethanol injection(PEI), surgical resection or others should be considered for the effective control of the HCCs.

Brain-computer interface : a single neuron study

Hyung-Cheul Shin(신형철),이현주,이은주,김상억,김미영,김영실,송성호,김성준,신형철 한국실험동물학회 2004 한국실험동물학회 학술발표대회 논문집 Vol.2004 No.-

가솔린 직접분사엔진의 흡기과급에 따른 성층화 연소에 미치는 영향

박형철(Hyung-Cheul Park),김미로(Mi-Ro Kim),조남효(Nam-Hyo Cho) 한국자동차공학회 2002 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2002 No.5_1

The effects of pressure charge on combustion stability and emissions have been analyzed in a GDI single cylinder engine. A late injection mode of stratified condition at 1200~2400rpm was tested and the charge pressure ratio was increased up to 1.5: 1. In-cylinder CFD analysis has been also performed to understand in-cylinder flow and fuel spray behavior. With a higher charge pressure ratio and a constant air-fuel ratio of 40:1 IMEP was increased greatly due to the increased amount of intake air mass. ISFC was improved by increasing the engine load, and the limiting stratification zone was extended to a higher engine speed, but a stable ignition timing zone was limited. ISCO was increased slightly with the increase of IMEP while ISHC was decreased. Intercooling was not used in this study but natural air cooling by a long flexible intake hose, therefore an appropriate turbocharging condition should be studied further to understand the effect of charge intake temperature on NOx emissions etc.

A Prognostic Model to Predict Clinical Outcome in Gastric Cancer Patients with Bone Metastasis

Park, Hyung Soon,Rha, Sun Young,Kim, Hyo Song,Hyung, Woo Jin,Park, Ji Soo,Chung, Hyun Cheol,Noh, Sung Hoon,Jeung, Hei-Cheul S. Karger AG 2011 Oncology Vol.80 No.1

<P>Abstract</P><P><I>Background:</I> The clinicopathological manifestations and treatment outcomes of bone metastasis of gastric cancer are largely unknown. We delineated a prognostic model to identify different risk groups on the basis of clinical parameters. <I>Methods:</I> Patients who had bone metastasis at the time of diagnosis of gastric cancer (synchronous metastasis) or who developed bone metastasis during follow-up (metachronous metastasis) were retrospectively reviewed from January 1998 to May 2008. <I>Results:</I> Bone metastasis was identified in 203 (2.4%) of 8,633 patients: 126 patients (62%) with synchronous metastasis and 77 patients with metachronous metastasis. The median time to event was 16 months (range 4–87). As for treatment, 120 patients (59%) received systemic chemotherapy. The median survival time was 103 days (95% CI 80–126). Poor performance status [Eastern Cooperative Oncology Group 3–4; relative risk (RR) = 1.91, p = 0.011], multiple bone metastasis (RR = 2.593, p = 0.002), and abnormal carcinoembryonic antigen (RR = 1.779, p = 0.004) implied independent factors for survival. For patients who had zero to two of these factors identified, chemotherapy had a beneficial effect (175 vs. 43 days; p < 0.0001). <I>Conclusion:</I> We recommend that the therapeutic approach with bone metastasis be customized to facilitate the risk stratification, so as to consequently provide the most appropriate therapy for each patient.</P><P>Copyright © 2011 S. Karger AG, Basel</P>