소아 궤양성 대장염의 수술적 치료 성적

김지훈,김현영,정성은,박귀원,김우기,Kim, Ji-Hoon,Kim, Hyun-Young,Jung, Sung-Eun,Park, Kwi-Won,Kim, Woo-Ki 대한소아외과학회 2005 소아외과 Vol.11 No.2

Ulcerative colitis, an inflammatory bowel disease, is primarily managed medically with a combination of 5-ASA and steroids. However, this chronic disease requires surgical management if symptoms persist or complications develop despite medical management. The clinical course, indications and outcome of surgical management of 21 patients under the age of 15 who were endoscopically diagnosed with ulcerative colitis at the Seoul National University Children's Hospital between January, 1988 and January, 2003 were reviewed. Mean follow up period was 3 years and 10 months. The mean age was 10.3 years old. All patients received medical management after diagnosis and 8 patients (38 %) eventually required surgical management. Of 13 patients who received medical management only, 7 patients (53 %) showed remission, 4 patients are still on medical management, and 2 patients expired due to congenital immune deficiency and hepatic failure as a result of sclerosing cholangitis. In 8 patients who received surgical management, the indications for operation were, 1 patient sigmoid colon perforation and 7 patients intractability despite medical management. The perforated case had a segmental colon resection and the other 7 patients underwent total colectomy with ileal pouch-anal anastomosis. One patient expired postoperatively due to pneumonia and sepsis. and 1 is still on medical management because of mild persistent hematochezia after surgery. Six other operated patients are doing well without medical therapy. Pediatric ulcerative colitis patients can be surgically managed if the patient is intractable to medical management or if complications such as perforation are present. Total colectomy & ileal pouch-anal anastomosis is thought to be the adequate surgical method.

혈액질환에 속발하는 이차성 위암

김지훈,지성배,허훈,진형민,김욱,김동욱,이종욱,민우성,김춘추,전해명,Kim, Ji-Hoon,Jee, Sung-Bae,Huh, Hoon,Chin, Hyung-Min,Kim, Wook,Kim, Dong-Wook,Lee, Jong-Wook,Min, Woo-Sung,Kim, Choon-Choo,Jeon, Hae-Myung 대한위암학회 2007 대한위암학회지 Vol.7 No.4

Purpose: Patients with hematologic diseases such as chronic myeloid leukemia (CML) or chronic lymphoid leukemia (CLL) are known to have an increased chance of acquiring a secondary neoplasm. Stomach cancer is one of the most common malignant diseases in Korea, and we investigated whether the incidence of secondary stomach cancer in patients with a hematologic disease increases, in order to determine if a more intensive screening program for detecting secondary gastric cancer was required. We also investigated the safety of performing a gastrectomy in hematologic disease patients. Materials and Methods: From 1992 to 2006, the medical records of 8376 patients diagnosed with one of the six common hematologic diseases were reviewed. Results: Nine secondary stomach cancers were found among the 8376 patients during the 15-year observation period. No surgical-related complications occurred, and there was no recurrence of stomach cancer if detected early. Conclusion: It seems that a more intensive screening program for detecting secondary gastric cancer in hematologic disease patients is not required, and surgery is not risky in these patients. 목적: 만성 골수성 백혈병이나 말성 림프구성 백혈병에서 이차성 암의 위험은 증가하는 것으로 알려져 있다. 백혈병을 비롯한 혈액질환을 가진 환자에서 우리나라에서 가장 흔한 암 가운데 하나인 위암의 위험이 증가하는지 조사하여 혈액질환 환자를 대상으로 위암에 대한 보다 적극적인 검진이 필요한지 알아보고자 하였다. 또한 응고장애나 면역저하와 같은 수술에 관련된 위험인자가 있을 수 있는 혈액질환 환자에서 위암 수술이 안전하게 이루어질 수 있는지에 대해 조사하고자 하였다. 대상 및 방법: 지난 15년가 성모병원에서 백혈병 및 다발성 골수종, 재생불량성 빈혈로 진단받은 8,376명의 환자를 대상으로 의무기록을 후향적으로 조사하였다. 결과: 총 9예의 이차성 위암이 확인되었다. 감염이나 출혈등 수술관련 합병증은 발생하지 않았으며, 조기에 발견된 경우 재발도 관찰되지 않았다. 결론: 위암의 빈도가 일반인에 비해 크게 증가하지 않아 혈액질환 환자에서 이차성 위암의 감시를 위한 집중적인 프로그램이 따로 도입되어야 할 필요성은 없는 것으로 생각되며, 혈액질환 환자의 위암 수술에 있어 합병증도 크게 증가하지는 않는 것으로 생각된다.

인접전류패턴을 사용한 변형된 방향 대수적 영상복원법

김지훈,김찬용,김경연,최봉열,Kim, Ji Hoon,Kim, Chan Yong,Kim, Kyung Youn,Choi, Bong Yeol 대한전자공학회 2012 전자공학회논문지 Vol.50 No.8

전기 임피던스 단층촬영법(electrical impedance tomography, EIT)에서 관심 대상물 내부 영상을 복원하는 방법 중 하나인 방향 대수적 영상복원법(directional algebraic reconstruction technique, DART)은 삼각함수형태로 설계된 전류패턴을 외부 전극에 인가하고 이로부터 얻어지는 전압과의 상관관계를 이용하여 영상복원 알고리즘의 입력인 각 전극사이의 저항을 유도하게 된다. 이때, 저항유도 시간이 발생하고 이는 DART 알고리즘을 실시간 영상복원에 적용하는데 장애가 되고 있다. 이 논문에서는 저항유도 시간의 문제를 해결하기 위하여 기존에 사용하던 삼각함수형태의 전류패턴대신 인접전류패턴을 사용한 변형된 방향 대수적 영상복원법(modified directional algebraic reconstruction technique, mDART)을 제안한다. 제안한 방법은 주입한 전류와 측정된 전압으로부터 저항을 유도하지 않고 측정전압을 바로 복원 알고리즘의 입력으로 사용하기 때문에 DART의 영상복원시간의 대부분을 차지하는 저항유도 시간을 없앨 수 있을 뿐만 아니라 인접전류패턴을 사용하여 복원영상의 질도 향상시킬 수 있다. 이 논문의 타당성을 입증하기 위하여 모의실험을 수행하였으며 제안한 방법은 기존 방법보다 복원시간의 개선뿐만 아니라 영상오차 관점에서도 성능이 개선됨을 확인하였다. The directional algebraic reconstruction technique (DART) using the trigonometric current pattern is one of the image reconstruction algorithms in electrical impedance tomography (EIT). This method needs to compute resistances between electrode pairs as using relation between the injected currents and measured voltages for the reconstruction of the inner image. The delay time is incurred in this process. Therefore this paper proposes modified directional algebraic reconstruction technique (mDART) using the adjacent current pattern instead of the trigonometric current pattern to solve the delay time for initial resistance values. The proposed method uses measured voltages instead of computed resistances in the reconstruction algorithm. Hence this method can eliminate the delay time because it does not use the resistances. In conclusion, the proposed method improves image quality and image reconstruction time by using the adjacent current pattern. To prove performance of the proposed method, we carried on computer simulation of various cases.

김제시 간척지역 천부 지하수내 철 환원작용 특성에 대한 고찰

김지훈,정태진,류종식,김락현,Kim, Ji-Hoon,Cheong, Tae-Jin,Ryu, Jong-Sik,Kim, Rak-Hyeon 대한자원환경지질학회 2013 자원환경지질 Vol.46 No.1

간척지를 포함하고 있는 연구지역에서 육지에서 해안지역으로 근접할수록 측정된 지하수의 산화환원 전위 (Eh)와 용존 산소량 (DO)은 낮게 관찰되었다 (Eh: 0.57 V ${\rightarrow}$ 0.13 V, DO; 9.7 mg/l ${\rightarrow}$ 1.3 mg/l). 이는 연구지역 지하수의 산화환경이 육지에서 해안가로 근접할수록 호기성 환경에서 아혐기성/혐기성 환경으로 변화한다는 것을 의미한다. 또한 지하수 수질 분석 결과에 의하면 철이온 (Fe)이 지하수에 많이 포함되어 있으며 (> 20 mg/l), 대부분의 2가 철로 존재한다. 이러한 연구지역 해안가 지하수들의 특징들은 지하수들이 철의 환원작용 (Fe reduction)이 일어날 수 있는 혐기성 환경에 위치하고 있음을 지시해준다. 철 환원작용이 일어나기 위해서는 3가 철의 공급원이 필요한데, 관측정 퇴적물의 철이온 추출실험에 의하면 연구지역의 퇴적물은 철 환원작용에 필요한 3가 철이온에 대한 충분한 공급원 역할을 할 수 있다. 따라서 분석한 지하수 및 퇴적물의 결과들을 종합해석하면, 연구지역에서 일어나는 철 환원작용은 갯벌의 간척활동과 많은 관련을 가지고 있는 것으로 추정된다. The study area is located on the western coastal region of Korea, partly had been reclaimed lands. Groundwaters of the coastal area show lower Eh and DO values (Eh: 0.57 V ${\rightarrow}$ 0.13 V, DO; 9.7 mg/l ${\rightarrow}$ 1.3 mg/l), and higher Fe concentrations (> 20 mg/l) than those of the inner land (< 0.3 mg/l), indicating that the redox condition of groundwater changes from oxic into suboxic/anoxic conditions as it flows from the inland toward the coastal area. In addition, Fe speciation of groundwater from the coastal area demonstrates that the most dissolved Fe exist as $Fe^{2+}$, reflecting that groundwater is under the anoxic condition to sufficiently occur Fe reduction. According to the result of Fe extraction with the sediment samples from three wells (A, B, C), the sediments provide enough $Fe^{3+}$ to occur the Fe reduction in the groundwater. Integrated all results of the groundwater and sediment, we infer that the Fe reduction to occur in groundwater is associated with the reclamation processes of the study area.

부유형 해양 광생물반응기를 이용한 자외선과 초기 미세조류 접종 농도와의 상관관계 규명

김지훈,박한울,정성균,김수권,김희윤,박용성,홍한마루,이철균,Kim, Z-Hun,Park, Hanwool,Jung, Seong-Gyun,Kim, Su-Kwon,Kim, Hee-Yun,Park, Yong Sung,Hong, Han Ma Roo,Lee, Choul-Gyun 한국해양바이오학회 2015 한국해양바이오학회지 Vol.7 No.2

The purpose of this study was to investigate a relationship between ultraviolet radiation and initial cell density (ICD) of microalgae using a floating marine photobioreactor (PBR). To examine the effect of ultraviolet (UV) radiation in sunlight on biomass productivity as a function of ICD, 0.5-L floating PBRs covered with or without UV cut-off film were placed in an outdoor rectangular tank containing 200 L of water. At the lower ICDs, 0.01 and 0.05 g/L, biomass productivities in the PBRs without UV cut-off film decreased by $278{\pm}21%$ and $222{\pm}3%$ compared with those with the film, respectively. In contrast, the presence of UV cut-off film did not have a significant effect on biomass productivities at the higher ICDs, 0.25 and 1.25 g/L. When the differences in biomass productivity made by the UV cut-off film were plotted against the sum of cell projection area per light receiving area of the PBR, the results revealed that the inhibitory effect of UV on biomass productivity can be negligible when the sum of cell projection area is equal to the light receiving area of the PBR. These results show that photoinhibition caused by UV radiation could be eliminated via operating the PBR with a proper ICD.

고전압과 폴리에틸렌 분말의 표면 개질이 열융착시킨 PET 부직포 매트의 물성에 미치는 영향

김지훈,김영호,유기옥,Kim, Ji Hoon,Kim, Young Ho,Ryu, Ki Ok 한국섬유공학회 2014 한국섬유공학회지 Vol.51 No.6

An eco-friendly process for the fabrication of melt-fixed PET non-woven mats was developed to improve upon conventional production methods for floor or car mats by treating PET non-woven fabrics with polymer solutions of organic solvents. Thermoplastic powders with low melting points were dosed and distributed into PET non-woven fabrics with the application of high voltage, and then melt-fixed at an elevated temperature. Both unmodified polyethylene (PE) and poly(methacrylic acid) (PMA)-grafted PE (PE-g-PMA) with a grafted yield of 15.7% were used as base thermoplastic powders. Varying the amount of PE (modified or unmodified) powder, as well as the applied voltage, affected the mechanical properties of the melt-fixed mats. These effects were investigated by mechanical testing. Results showed that the tensile breaking stress of the melt-fixed mats increased, while the strain at break decreased, with increases in the amounts of PE or PE-g-PMA powder and the applied voltage. However, the mechanical properties of the mats were further enhanced when PE-g-PMA powder was used compared to unmodified PE powder. The application of high voltages during the powder treatment caused the hydrophilic polar groups in PE-g-PMA to distribute the grafted powder more evenly throughout the PET fabric. The resulting greater evenness in the distribution of PE-g-PMA made the grafted powder more effective in enhancing the mechanical properties of the melt-fixed mats more than the unmodified PE powder.

Bio-Oss 골이식이 치아맹출에 미치는 영향에 관한 동물실험 연구

김지훈,장채리,최병호,Kim, Ji-Hun,Chang, Chae-Ri,Choi, Byung-Ho 대한구강악안면외과학회 2010 대한구강악안면외과학회지 Vol.36 No.6

Introduction: There are few reports on tooth eruption through Bio-Oss grafts. To our knowledge, there are no reports on whether teeth can erupt normally through the grafts. The aim of this study was to examine the effect of Bio-Oss grafts on tooth eruption in a canine model. Materials and Methods: In five 10-week-old dogs, the deciduous third mandibular molars in one jaw quadrant of each animal were extracted and the fresh extraction sockets were then filled with Bio-Oss particles (experimental side). No such treatments were performed on the contralateral side (control side). A clinical and radiological evaluation was carried out every other week to evaluate the eruption level of the permanent third mandibular premolars and compare the eruption levels between the two sides. Results: At week 4 after the experiment, the permanent third premolars began to erupt on both sides. At week 12, the crown of the permanent third premolar emerged from the gingiva on both sides. At week 20, the permanent third premolars on both sides erupted enough to occlude the opposing teeth. No significant differences were found between the control and experimental sides in terms of the eruption speed of the permanent third molars. Conclusion: These findings demonstrate that the grafting of Bio-Oss particles into the alveolar bone defects does not affect tooth eruption.

Skid Launching System을 위한 Floating Dock Control Simulator의 개발

김지훈,이장용,박석주,Kim, Jee-Hun,Lee, Jang-Yong,Park, Sok-Chu 한국항해항만학회 2008 한국항해항만학회지 Vol.32 No.1

최근 중국의 경제 활성화에 힘입어 물동량이 급증하게 되었고, 따라서 선박의 폭발적인 요구도 생기게 되었다. 그러나 조선소의 건조 능력은 드라이도크의 용량에 의하여 크게 의존할 수밖에 없는 실정이다. 드라이도크의 건조는 상당히 긴 기간을 필요로 하고, 또 건조 비용도 많이 들기 때문에 장기적인 조선의 수요의 관점에서 타당성을 검토할 필요가 있다. 더욱 시급한 것은 당장 목전에 와 있는 조선 수요를 적절히 감당해 주어야 한다는 점이다. 그래서 여러 조선소에서는 드라이도크의 부족을 메우기 위한 다양한 방안들이 검토되었다. 현대중공업에서는 육상 건조법을 도입하였고, 삼성중공업과 STX 조선소에서는 플로팅도크에서 건조하는 방법을 도입하였다. 본 논문은 육상에서 건조한 대블록을 플로팅도크에 밀어 넣는 Skid Launching System(SLS)을 위한 도크 제어 시뮬레이터를 개발하여 모의 조정한 결과를 보인다. 대형 블록을 플로팅도크에 밀어 넣기 전에 발라스트 순서도를 작성하여 모의 작업을 통하여 안정성을 확인한 뒤 실제 작업 시 이 순서대로 작업을 하여 플로팅도크의 안전성을 확보하기 위한 장치를 개발한 것이다. Since the shipbuilding industry is at its peak to assimilate the large volume of orders in recent years, the Floating Dock has been an alternative to the dry dock which takes a certain period of time to build. Hence the use of Floating Dock is steadily increasing. Since the Skid Launching System(SLS) is used in Floating Dock, the balancing of the ship while launching is important and achieved by adjusting the Ballast tank of the Floating Dock. In this paper a Floating Dock Control Simulator for SLS is developed through the on-line interface of VRC(Valve Remote Control), Tank Level & Draft Measuring System and Valve Control algorithm on Simulation Tank Plan.

골 성숙도 단계의 골령 평가를 위한 Greulich-Pyle 방법을 이용한 인공지능 프로그램의 활용

김지훈,서혜준,박소영,이은경,정태성,남옥형,최성철,신종현,Jihoon Kim,Hyejun Seo,Soyoung Park,Eungyung Lee,Taesung Jeong,Ok Hyung Nam,Sungchul Choi,Jonghyun Shin 대한소아치과학회 2023 大韓小兒齒科學會誌 Vol.50 No.1

The purpose of this study was to measure bone age using an artificial intelligence program based on the Greulich-Pyle (GP) method to find out the bone age corresponding to each stage of cervical vertebral maturation (CVM) and the middle phalanx of the third finger (MP3). This study was conducted on 3,118 patients who visited pediatric dentistry at Kyung Hee University Dental Hospital and Pusan National University Dental Hospital from 2013 to 2021. The CVM stage was divided into 5 stages according to the classification by Baccetti, and the MP3 stage was divided into 5 stages according to the methods of Hägg and Taranger. Based on the GP method, bone age was evaluated using an artificial intelligence program. The pubertal growth spurt in the CVM stage was CVM II and III. The mean bone age in CVM II was 11.00 ± 1.81 years for males and 10.00 ± 1.49 years for females, and in CVM III, 13.00 ± 1.46 years for males and 12.00 ± 1.44 years for females (p < 0.0001). The pubertal growth spurt in the MP3 stage was MP3 - G stage. The bone age at the MP3 - G stage was 13.14 ± 1.07 years for males and 11.40 ± 1.09 years for females (p < 0.0001). Bone age evaluation using artificial intelligence is worth using in clinical practice, and it is expected that a faster and more accurate diagnosis will be possible.

순 Ti 박판 GTA 용접부의 기계적 성질 및 성형성에 미치는 공정변수의 영향

김지훈,홍재근,염종택,박노광,강정윤,Kim, Jee-Hoon,Hong, Jae-Keun,Yeom, Jong-Taek,Park, Nho-Kwang,Kang, Chung-Yun 대한용접접합학회 2010 대한용접·접합학회지 Vol.28 No.4

In this work, the effect of welding variables on weldability of gas tungsten arc(GTA) welding was investigated with experimental analysis for a commercial pure(CP) titanium (Grade.1). The GTA welding tests on sheet samples with 0.5mm in thick were carried out at different process variables such as arc length, welding speed and electrode shape. In order to search an optimum arc length with full penetration, bead- on-plate welding before butt-welding were performed with different arc length conditions. From the bead- on-plate welding results, the optimum condition considering arc stability and electrode loss was obtained in the arc length of 0.8mm. Butt-welding tests based on the arc length of 0.8mm were carried out to achieve the optimum conditions of welding speed and electrode shape. Optimum conditions of welding speed and electrode shape were suggested as 10 mm/s and truncated electrode shape, respectively. It was successfully validated by the microstructural observation, tensile tests, micro-hardness tests and formability tests.