• Clinical and Experimental Pediatrics
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• v.45 no.7
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• pp.912-916
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• 2002

Cord blood is a useful source of allogeneic hematopoietic stem cells for bone marrow reconstitution. The number of umbilical cord blood transplants is increasing worldwide. In this a case 15-month-old boy with acute myeloid leukemia was treated with umbilical cord blood transplant from an HLA-3 loci mismatched unrelated donor. Granulocyte recovery greater than $500/mm^3$ occurred at day 49, and the platelet recovered greater than $20,000/mm^3$ independent of transfusion at day 81 after stem cell infusion.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.03a
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• pp.57-60
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• 1998

Darwin Machine은 자기 자신의 구조를 전자적인 속도로 진화해 나가는 하드웨어로서 복잡한 구조와 성질으 진화 기법을 사용하여 만들어 나가는 진화공학(Evolutionary Engineering)의 한 예이다. 하드웨어가 전자적인 속도로 진화하기 위해서는 각각으리 하드웨어 구성요소들이 병렬적으로 작동해햐 하는데 셀룰라 오토마타는 이러한 문제를 해결하는 적합한 구조이며, 하드췌어에 쉽게 이식할 수 있는 장점이 있다. 신경망의 학습 능력과 진한 연산을 이용하면 효율적인 진화를 유도할 수 있다. 본 논문에서는 이러한 하드웨어 구현을 위한 셀룰라 오토마타에 기반한 신경망을 보이고자 한다.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.927-938
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• 2021

A similar magnitude of non-gravitational perturbations are act on the formation flying low earth orbit satellites with a certain time difference. Using this temporal correlation, the non-gravity acceleration of the low earth orbiting satellites can be transferred for the othersatellites. There is a period in which the accelerometer data of one satellite is unavailable for GRACE and GRACE-FO satellites. In this case, the accelerometer data transplant method described above is officially used to recover the accelerometer data at the Jet Propulsion Laboratory (JPL). In this paper, we proposed a model for predicting accelerometer data of formation flying low earth orbit satellites using a neural network (NN) model to improve the estimation accuracy of the transplant method. Although the transplant method cannot reflect the satellite's position and space environmental factors, the NN model can use them as model inputs to increase the prediction accuracy. A prediction test of an accelerometer data using NN model was performed for one month, and the prediction accuracy was compared with the transplant method. The NN model outperformsthe transplant method with 55.0% and 40.1% error reduction in the along-track and radial directions, respectively.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.2 s.314
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• pp.18-23
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• 2007

Intra-body communication' is a wireless communication technology that uses a body as a transmission medium for electrical signals. Generally, an 'earth ground' is used to create an electric field for operating the system; however this operating method could not apply to telemetry for implanted neural prosthetic devices. So this paper suggests a newly designed intra-body communication for neural prosthetic devices. A floating system which has a couple of electrodes with body was studied to remove an influence of the 'earth ground'. We found that 10MHz is the most suitable carrier frequency in skin experiments and over 3MHz in subcutaneous experiments. The system has been applied to a current stimulator circuit for cochlear implant that uses pulse width modulation (PWM) method at 480kbps rate successfully.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.152-156
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• 2005

Background: Occlusive complications after arterial revascularization are difficult to treat and have high recurrence rate. This study was performed to establish an effective treatment modality and to evaluate the factors affecting the occlusive complications by analysis of clinical data. Material and Method: During the period of 5 years. 33 patients (55 reoperations) were studied at the Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital following 173 arterial revascularization surgeries. The clinical characteristics, operating methods, the time intervals of reoperation, used graft, and the results of treatment were evaluated retrospectively. Result: All the patients were men except one and the mean age was 63.5 years old. The mean time internal from first operation to reoperation was 11.9 months. The cause of arterial occlusive diseases were 28 atherosclerosis and 5 Burger's diseases, Associated diseases were Hypertension $(57.6\%)$, Diabetes mellitus $(33.3\%)$, heart failure $(18.2\%)$, and so on. The mean rate of reoperation was 1.67 times and the most common type of first operation was femoro-popliteal bypass grafting $(57.6\%)$. The graft that used revascularization surgery were 25 cases of PTFE and 6 case were Dacron. There was no statistical difference between two groups. The kinds of reoperations were thrombectomy in 20 cases, angioplasty 18 cases, re-bypass surgery in 13 cases, and lumbar sympathectomy in 4 cases. The results of reoperation were 15 cases of functional recovery, 7 cases of limb salvage, 5 cases of above-knee amputation. 3 cases of below-knee amputation and 3 deaths. Conclusion: The main cause of occlusive complications are occlusion of inflow or outflow artery. Treatments were different according to the first operation methods and graft used. The most frequent time of reoperation was within one year after the first operation. We believe that graft surveillance especially during the first year is very important factor in observing the patient. We can look forward to improving limb salvage rate to perform additional treatment such as radiological interventions and lumbar sympathectomy.

• Annals of Clinical Neurophysiology
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• v.13 no.1
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• pp.58-60
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• 2011

Chronic graft-versus-host disease (GVHD) is a well-known complication of allogeneic bone marrow transplantation (BMT) and has heterogeneous manifestations, with multi-organ involvement. Recently, polymyositis (PM) was reported to be a rare manifestation of chronic GVHD. Here, we report a 30-year-old woman who was diagnosed with PM after allogeneic BMT.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.270-270
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• 2004

이 연구는 Ⅰ) 혈관 폐색에 의한 인지 및 기억장애 동물모델에서 뇌졸중 치료제로써 인간배아줄기 세포의 신경세포 보호효과 및 작용기간을 밝히며, Ⅱ) 행동 약리학적 연구를 통해 기억력증진에 미치는 효과에 대해 밝히고 혈관 폐색에 의한 동물모델에서의 기억기능 증진 및 세포효과를 검증하고자 실시하였다. 중대 뇌동맥 폐색에 의한 쥐의 동물모델은 Sprague Dawley계 흰 쥐(260∼300 g)의 국소 중대뇌동맥을 일시적으로 폐색시켜 만들었다. 본 연구(미국 국립보건원에 등록된 MB03세포)에 사용된 인간배아줄기세포는 3×10⁴ cells/㎠ 밀도의 배양접시 내에서 4일 동안 embryoid bodies(EBs)의 형성을 위해 집합체를 이루도록 유도하였다. (중략)

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.6.1-6.1
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• 2009

신경외과는 뇌수술과 척추수술로 나눈다. 이중뇌수술 분야에서는 두개강내압 항진시 감압술이라고 '머리의 뚜껑을 연다'라는 표현과 마찬가지로 두개골의 일부분(손바닥크기)을 절제하는 수술이 있다. 이때 과거에는 떼어낸 뼈를 복부의 피하지방밑에 심어서 보관을 하다가 3-6개월 후 환자의 뇌상태가 안정이 되면 다시 꺼내어 제자리에 놓았는데, 골편이 피하지방에서 녹는 경우가 다소 있고, 복부에 이식한 장소가염증이 생기는 경우도 있어서 요즘은 냉동고에서 -70도를 유지하여 보관 후 나중이 복원 수술을 할 때녹여서 사용한다. 이를 '자가골 두개성형술' 이라 한다. 하지만골편의 오염이나 소실 혹은 1차 두개성형술 후 감염 등 어쩔 수 없이 자가골을 사용 못하는 경우에는인공으로 두개골편 모형을 제작하여 '뚜껑'으로 사용해야 한다. 현재PMMA를 이용하여 수술 시 모형을 제작하는 방법이 많이 사용되며 최근 단단한 스펀지 형태의 인공제품이 사용되고 있으나 가격이 매우비싸지만 스펀지 기공내로 자가골이 자란다는 장점이 있다. 척추수술 분야에서는 뼈 대치품을 비교적 많이필요로 한다. 즉 척추 후방고정을 하는 경우 원래 수술의 목적인 감압술이나 교정술 등을 한 후 척추분절간 쇠(티타늄사용)고정을 한 뒤에 뼈조직(자가골이나 동종이식골, DBM, HA stick) 등을 충분히 사용하여덮어줌으로써 분절간 골유합을 유도할 때 많은 양이 필요하며, 척추 전방으로 수술을 하는 경우에도 디스크공간이 빈 상태에서 Cage(추체와 추체를 지지하는 작은 상자모양) 내에뼈조직을 넣어서 척추분절간 골유합이 일어나도록 한다. 최근 HA를 cage 대용품으로 사용한 경우에서 HA가 부서지는 경우가 기사화된바 있다. 또한 경추의 추체 내에 작은 구멍만 뚫고 디스크 수술을 한 후에 그 구멍에 HA+B-TCP 소재를 넣어 천연뼈의 성장 유도를 위해 사용되는 등 신경외과의 다양한 분야에서 생체소재들이 사용되고 있다.

• Childhood Kidney Diseases
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• v.13 no.2
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• pp.130-137
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• 2009

Purpose : Stem cell transplantation (SCT) has gained worldwide acceptance as a treatment for hematologic disorders. This study was performed to evaluate the clinical characteristics and outcomes of the acute kidney injury after SCT in children. Methods : The records of 53 patients who were treated with SCT at the pediatric department of Yeungnam University Hospital between January, 1996 and April, 2009 were used as subjects. Their were divided into two groups ; 'Early renal insufficiency' (ERI, n=18) and 'Non-early renal insufficiency' (NERI, n=35). ERI had greater than 25% of drop in GFR after SCT. Results: Total 53 patients were analyzed. In cord blood SCT (n=11), ERI was 4 (36.4%) and NERI was 7 (63.6%). In bone marrow SCT (n=16), ERI was 8 (50.0%) and NERI was 8 (50.5%). In autologous peripheral blood SCT (n=26), ERI was 6 (23.1%) and NERI was 20 (76.9%). There is no difference in both groups according to kinds of SCT. GVHD was developed in 22 patients, and there is no difference in each group. Twenty two of 53 patients died. ERI was 12 (66.7%) and NERI was 10 (28.6%). Acute renal failure is most important cause of the deaths. Conclusion : Out of 53 pediatric patients who were treated with SCT, 18 patients had greater than 25% of drop in GFR. There is no difference in both groups according to kinds of SCT. GVHD was found in 22 patients and there is no relation between GVHD development and acute kideney injury.

• Progress in Medical Physics
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• v.19 no.3
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• pp.157-163
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• 2008

Retinal prosthesis is regarded as the most feasible method for the blind caused by retinal diseases such as retinitis pigmentosa or age-related macular degeneration. One of the prerequisites for the success of retinal prosthesis is the optimization of the electrical stimuli applied through the prosthesis. Since electrical characteristics of degenerate retina are expected to differ from those of normal retina, we investigated differences of the retinal waveforms in normal and degenerate retina to provide a guideline for the optimization of electrical stimulation for the upcoming prosthesis. After isolation of retina, retinal patch was attached with the ganglion cell side facing the surface of microelectrode arrays (MEA). $8{\times}8$ grid layout MEA (electrode diameter: $30{\mu}m$, electrode spacing: $200{\mu}m$, and impedance: 50 $k{\Omega}$ at 1 kHz) was used to record in-vitro retinal ganglion cell activity. In normal mice (C57BL/6J strain) of postnatal day 28, only short duration (<2 ms) retinal spikes were recorded. In rd/rd mice (C3H/HeJ strain), besides normal spikes, waveform with longer duration (~100 ms), the slow wave component was recorded. We attempted to understand the mechanism of this slow wave component in degenerate retina using various synaptic blockers. We suggest that stronger glutamatergic input from bipolar cell to the ganglion cell in rd/rd mouse than normal mouse contributes the most to this slow wave component. Out of many degenerative changes, we favor elimination of the inhibitory horizontal input to bipolar cells as a main contributor for a relatively stronger input from bipolar cell to ganglion cell in rd/rd mouse.