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Persistent Primitive Olfactory Artery Type 4 with Fusiform Aneurysm: A Case Report
Heecheol Park,Jin Wook Baek,Hae Woong Jeong,Young Jin Heo,Suyoung Yun,Ji-Yeon Han 대한영상의학회 2023 대한영상의학회지 Vol.84 No.6
The persistent primitive olfactory artery (PPOA) is a rare variant of the anterior cerebral artery, first reported in 1979. It reportedly has a high correlation with the development of aneurysms, owing to the hemodynamic stress induced by the structural characteristics of the hairpin turn. Herein, we present a rare case of PPOA type 4 with a fusiform aneurysm at the hairpin turn segment in a 46-year-old female with occasional headaches. Time-of-flight MR angiography and transfemoral cerebral angiography revealed an unusual branch arising from the left A1 segment, running anteromedially along the ipsilateral olfactory tract, and turning the hairpin posterior to the olfactory bulb. This branch continued into the left accessory middle cerebral artery, and a fusiform aneurysm was observed at the hairpin segment. No further treatment was performed, and follow-up imaging was recommended. Nevertheless, it is essential to recognize and diagnose these rare variations.
박희철(Heecheol Park),정환준(Hwanjun Jung),김석호(Seokho Kim),박민원(Minwon Park) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.5-3
HTS (High Temperature Superconductor) technology enables compact and high efficient power generators. To keep the superconducting state, the HTS rotor should be cool down to cryogenic temperature. In general, it is known that the optimum operation temperature is about 30 K considering the cost of the HTS conductors and cooling system. Therefore, cooling system should be designed to keep the temperature of the HTS rotor around 30 K. This can be realized by using the liquid neon thermosyphon cooled by crycooler. This paper describes the design process and experimental results for liquid nitrogen re-condensing cooling system. Heat loss of the torque tube is estimated. Flow areas for liquid and gaseous neon are determined considering the pressure drop. Experiments are performed to estimate the background loss of the cooling system itself and to investigate the heat loss through the torque tube. Additional heating is applied to verify the performance of the cooling system.
De-Lamination Characteristics of Coated Conductor for Conduction Cooled HTS Coil
Hwanjun Jeong,Heecheol Park,Seokho Kim,Minwon Park,In-Keun Yu,Sangjin Lee,Taejun Park,Kideok Sim,Hong-Soo Ha,Sang-Su Oh,Seung-Hyun Moon IEEE 2012 IEEE transactions on applied superconductivity Vol.22 No.3
<P>According to the continuous development of coated conductors and compact cryocoolers, research and development efforts for High Temperature Superconducting (HTS) magnets are increasing using conduction cooling method. To increase the cooling efficiency and thermal stability of the HTS magnet, the coated conductor is wound by wet-winding or epoxy impregnating in vacuum after dry-winding. Due to the large Lorentz force and thermal contraction, stress analysis of the composite material, which is composed of HTS conductor, insulation layer and epoxy layer, is necessary to assure the mechanical stability of the HTS magnets. Mechanical strength for a/b axis, which is parallel to the conductor surface, is usually strong enough to endure the large tensile stress due to the tough substrate material. However, c-axis strength, which is perpendicular to the conductor surface, is not strong enough to ensure the large Lorentz force. The de-lamination of the multi-layered HTS tape in a coil structure can occur and the results were previously reported. Therefore, the test data for allowable c-axis strength is necessary to design the mechanical stability of the HTS coil. This paper describes the experimental results for the c-axis tensile strength of various coated conductors. The results show the wide divergence of the c-axis tension force from 18 MPa to 53 MPa. Through the FEM analysis for multi-layered structure of the HTS tape, concept design for HTS tape of enhanced c-axis strength is suggested.</P>
박종한,이양현,김희철 대한신경정신의학회 1999 신경정신의학 Vol.38 No.1
연구목적 : 지역 사회에 거주하는 노인들에게 장기간에 걸쳐 인지기능의 자연적인 변화를 관찰하기 위하여 본 연구가 시행되었다. 대상 및 방법 : 1990년 1월부터 같은 해 12월까지 경상북도 포항시 죽장면에 거주하는 65세 이상의 노인 702명에게 한국판 간이정신상태검사(Korean version of mini-mental state examination. MMSEK)가 시행되었다 이들 중 440명에 대해서는 1995년 11월부터 1996년 6월까지 인지기능장애 진단도구가 시행되었다. 이 도구에는 MMSEK의 모든 문항들이 포함되어 있어서 2회 시행된 MMSEK 점수를 비교할 수 있었다. 결 과 : 약 6년 동안에 MMSEK 총점은 1.52±3.45 감퇴되었고, 감퇴율은 6.42%이었다. 기억 등록은 유의한 변화가 없었고, 시간에 대한 지남력, 장소에 대한 지남력, 기억 회상, 집중/계산, 언어 기능은 유의한 감소를 보여 주었으나, 이해/판단력은 오히려 유의하게 증가되었다. 집중/계산과 기억 회상이 가장 많이 감퇴했고, 그 다음은 언어 기능과 시간에 대한 지남력, 그리고 장소에 대한 지남력이었다. MMSEK 총점의 변화는 성, 교육수준, 그리고 1차 MMSEK 총점과는 무관했다. 하위 검사들 중에서 언어 기능의 감퇴는 유학 수준 노인들에 비해서 무학-문맹 노인들에서 더 심했다. 연령이 증가할수록 각 하위 검사 점수의 감퇴가 더 심했고, 이해/판단력의 호전은 더 미미했다. 1차 MMSEK 점수와 각 하위 검사 점수의 변화간에는 일치된 소견이 발견되지 않았다. 단계별 중다회귀분석 결과, MMSEK 점수의 감퇴에 유의한 영향을 미치는 변수로는 연령, 1차 MMSEK 총점, 그리고 교육수준이 확인되었다. 이들 세 변수는 MMSEK 총점 감퇴 변량의 16.4%만 설명해 주었다. 결 론 : 노인들에서 장기간에 걸친 인지기능 감퇴는 미미하고, 변화의 양상은 인지기능의 각 영역마다 다른 양상을 보여 주었다. 또 인지기능의 감퇴를 설명해주는 변수로는 연령, 1차 MMSEK 총점, 그리고 교육수준이 확인되었으나 그 외에는 다른 변수가 있음을 강력히 시사한다. Objectives : To study was conducted to delineate the long-term natural change of cognitive functions in aged community residents, using the Korean version of the mini-mental state examination(MMSEK). Method : The first MMSEK was administered to as the screening test for identification of dementia between January and December, 1990 in total of 702 persons. They were residents of a Myun area, Pohang, Kyunpook Province and 65 or more as of December 31. 1990. The MMSEK was repeated from November, 1995 to June, 1996, using the Cognitive Impairment Diagnosing Instrument and was successful in 440. Results : The 6-year mean(±SD) decline of the total MMSEK score was 1.52±3.45 and 6.42%. Of the subtests, memory registration showed no significant decline while comprehension/judgement improved significantly. The decline was most prominent in attention/calculation and memory recall, and then language, orientation in time and orientation in place in order. Change of the total score was not related to sex, education and the first total score. Decline of language function was more severe in the educated than in the noneducated-illiterate. Performances of all subtests declined significantly with aging and improvement of the comprehension/judgement was less prominent in the group aged 75 or more. Relations of the change with the first total score were inconsistent among the subtests. The stepwise multiple repression analysis revealed that age, the decline of MMSEK score. However, they could account for only 16.4% of the variance of decline of the total MMSEK score. Conclusion : Decline of the cognitive function was small during the 6-year period, and the change pattern was not homeogenous among the subtests. Age, the first total MMESK score and education were identified as significant, but not so important, factors accounting for the variance of the cognitive decline.