• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제25권1호
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• pp.28-36
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• 2014

Objectives : The goal of this study was to examine the association between zinc and lead level and symptoms of attention-deficit hyperactivity disorder (ADHD) among Korean children. Methods : A total of 89 clinic-referred children participated in the study (ADHD group=45, control group=44). The participants were 5-15 years old, and were mainly from urban areas of Seoul, Korea. ADHD was diagnosed using the Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version. We excluded children with a comorbid psychiatric disorder, medical illness requiring medication, or a prior history of taking ADHD medication. In order to evaluate the severity of ADHD symptoms, parents' Korean ADHD Rating Scale (K-ARS) was used. The ADHD diagnostic system (ADS) was used for evaluation of the severity of inattention and impulsivity. All participants completed the intelligence test and hair mineral analysis. Multiple regression analysis was used to examine the effect of hair zinc and lead levels on the K-ARS and ADS. We measured the predictive ability of the zinc and lead levels using logistic regression analysis. Results : The lead level explained the score for omission errors, commission errors, and response time SD in visual ADS in the ADHD group (adjusted $R^2$=.243, p<.01, adjusted $R^2$=.362, p<.01, and adjusted $R^2$=.275, p<.01), the score for omission errors of auditory ADS in ADHD group (adjusted $R^2$=.407, p<.01) and the entire group (adjusted $R^2$=.292, p<.01). Zinc was significantly explanatory for the K-ARS scores for the entire group (adjusted $R^2$=.248, p<.001) and the ADHD group (adjusted $R^2$=.247, p<.05). Conclusion : These findings suggest a possible role of zinc and lead in ADHD. Lead concentration in hair samples affected the ADS scores, and this was more prominent in children with ADHD. Children with ADHD had a lower zinc concentration in their hair, and the zinc concentration in hair showed negative correlation with the K-ARS score.

• 한국발생생물학회지:발생과생식
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• 제17권4호
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• pp.441-449
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• 2013

Recent study showed that T cells in the immune organs and peripheral blood are influenced by estradiol, leading to a dysfunction of the immune system. However, little is known about the thymic-gonadal relationship during the estrous cycle in mouse. Therefore, the purpose of this study was to elucidate the mechanism by which a change in estradiol levels during the estrous cycle regulates the development of T cells in the mouse thymus. Six-week-old ICR mice were used and divided into four groups, including diestrous, proestrous, estrous, and metestrous. We first confirmed that ER-${\alpha}$ and - ${\beta}$ estrogen receptors were expressed in thymic epithelial cells, showing that their expression was not different during the estrous cycle. There was also no significant difference in thymic weight and total number of thymocytes during the estrous cycle. To determine the degree of thymocyte differentiation during the estrous cycle, we analyzed thymocytes by flow cytometry. As a result, the percentage of CD4+CD8+ double-positive (DP) T cells was significantly decreased in the proestrous phase compared to the diestrous phase. However, CD4+CD8- or CD4-CD8+ (SP) T cells were significantly increased in the proestrous phase compared to the diestrous phase. In addition, the percentage of CD44+CD25- (DN1) T cells was significantly decreased in the estrous phase compared to other phases, whereas the percentages of CD44+CD25+ (DN2), CD44-CD25+ (DN3), and CD44-CD25- (DN4) were not changed during the estrous cycle. These results indicate that the development of thymocytes may arrest in the DP to SP transition stage in the proestrous phase displaying the highest serum level of estradiol. This study suggests that a change in estradiol levels during the estrous cycle may be involved in the regulation of thymocyte differentiation in the mouse thymus.

• 대한방사선기술학회지:방사선기술과학
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• 제38권3호
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• pp.187-197
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• 2015

본 연구는 복합부가여과에서 특성방사선을 제거하기 위해 사용되는, 알루미늄 여과판의 효율성을 분석하고자 구리 0.1, 0.2, 0.3 mm에 알루미늄 1 mm 사용 전, 후 에너지 스펙트럼 분석과 화질평가를 실시하였다. GATE를 이용하여 에너지 스펙트럼을 측정하고, 에너지별로 구분하여 평가 하였다. 화질평가는 PSNR, MAE, MSE, CNR, SNR 정성적 평가로는 국가암검진 흉부 평가표의 해상, 대조도 평가 7문항을 이용하였다. 에너지별 스펙트럼의 광자의 질 분석에서 저에너지 영역을 제외하고, 모든 영역 알루미늄 미사용 시 우수하였다. PSNR MAE, MSE, CNR, SNR, 정성적 평가는 알루미늄 미사용 시 같거나 우수했다. PSNR은 30 dB이상으로 모두 의미 있는 수치였고, 정성적 평가에서 T-test 검정은 p>0.05였다. 알루미늄 여과판은 에너지 스펙트럼 분석과 화질 평가에서 사용 전, 후 큰 효과가 없으므로, 디지털 방사선 장비의 보상능력 이용하면 알루미늄 여과판 사용 시 보다 선량 관리가 효과적이라 사료된다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.37-38
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• 2017

최근 방제 및 예찰과 같은 농작업에 단일 UAV(Unmanned Aerial Vehicle)시스템이 적용되고 있지만, 가반하중과 체공시간 등 기존시스템의 문제가 점차 대두되면서 작업 시간을 보다 단축시키고 작업 효율을 극대화 할 수 있는 농업용 멀티 UAV시스템의 필요성이 증대되고 있다. 본 논문에서는 작업자가 다수의 농업용 UAV를 효과적으로 제어할 수 있는 분산군집제어 알고리즘을 제안하며 알고리즘 검증 및 평가를 위한 시뮬레이터를 소개한다. 분산군집제어는 UAV 제어 계층, VP(Virtual Point) 제어 계층, 원격제어 계층으로 이루어진 3계층 제어구조를 가진다. UAV 제어 계층에서 각 UAV는 point mass로 모델링 되는 VP의 이상적인 경로를 추종하도록 제어한다. VP 제어 계층에서 각 VP는 입력 $p_i(t)=u^c_i+u^o_i+u^{co}_i+u^h_i$-(1)을 받아 제어되는데 여기서, $u^c_i{\in}{\mathbb{R}}^3$는 VP 사이의 충돌방지제어, $u^o_i{\in}{\mathbb{R}}^3$는 장애물과의 충돌방지제어, $u^{co}_i{\in}{\mathbb{R}}^3$는 UAV 상호간의 협조제어, $u^h_i{\in}{\mathbb{R}}^3$는 작업자로부터의 원격제어명령이다. (1)의 제어입력에서 충돌방지제어는 각 $u^i_c:=-{\sum\limits_{j{\in}{\eta}_i}}{\frac {{\partial}{\phi}_{ij}^c({\parallel}p_i-p_j{\parallel})^T}{{\partial}p_i}}$-(2), $u^o_c:=-{\sum\limits_{r{\in}O_i}}{\frac {{\partial}{\phi}_{ir}^o({\parallel}p_i-p^o_r{\parallel})^T}{{\partial}p_i}}$-(3)로 정의되면 ${\phi}^c_{ij}$와 ${\phi}^o_{ir}$는 포텐셜 함수를 나타낸다. 원격제어 계층에서 작업자는 햅틱 인터페이스를 통해 VP의 속도를 제어하게 된다. 이때 스케일변수 ${\lambda}$에 대하여 VP의 원격제어명령은 $u^t_i(t)={\lambda}q(t)$로 정의한다. UAV 시뮬레이터는 리눅스 환경에서 ROS(Robot Operating Systems)를 기반한 3차원 시뮬레이터인 Gazebo상에 구축하였으며, 마스터와 슬레이브 간의 제어 명령은 TCPROS를 통해 서로 주고받는다. UAV는 PX4 기반의 3DR Solo 모델을 사용하였으며 MAVROS를 통해 MAVLink 통신 프로토콜에 접속하여 UAV의 고도, 속도 및 가속도 등의 상태정보를 받을 수 있다. 현재 멀티 드론 시스템을 Gazebo 환경에 구축하였으며, 추후 시뮬레이터 상에 분산군집제어 알고리즘을 구현하여 검증 및 평가를 진행하고자 한다.

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.306-309
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• 2007

PXLM(Phosphor based x-ray light modulator) has a combined structure by phosphor, photoconductor, and liquid crystal and it can realize x-ray image of high resolution in clinical diagnosis area. In this study, we fabricated a photoconductor and investigated electrical and optical properties to confirm application possibility of radiator detector of PXLM structure. As photoconductor, amorphous selenium(a-Se), which is used most in DR(Digital radiography) of direct conversion method, was used and for formation of thin film, it was formed as $20{\mu}m-thick$ by using thermal vacuum evaporation system. For a produced a-Se film, through XRD(X-ray diffraction) and SEM(Scanning electron microscope), we investigated that amorphous structure was uniformly established and through optical measurement, for visible light of 40 $0\sim630nm$, it had absorption efficiency of 95 % and more. After fabricated a-Se film on the top of ITP substrate, hybrid structure was manufactured through forming $Gd_2O_3:Eu$ phosphor of $270{\mu}m-thick$ on the bottom of the substrate. As the result to confirm electrical property of the manufactured hybrid structure, in the case of appling $10V/{\mu}m$, leakage current of $2.5nA/cm^2$ and x-ray sensitivity of $7.31nC/cm^2/mR$ were investigated. Finally, we manufactured PXLM structure combined with hybrid structure and liquid crystal cell of TN(Twisted nematic) mode and then, investigated T-V(Transmission vs. voltage) curve of external light source for induced x-ray energy. PXLM structure showed a similar optical response with T-V curve that common TN mode liquid crystal cell showed according to electric field increase and in appling $50\sim100V$, it showed linear transmission efficiency of $12\sim18%$. This result suggested an application possibility of PXLM structure as radiation detector.

• 한국해양학회지:바다
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• 제18권1호
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• pp.47-52
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• 2013

생태계 질소 순환 연구에서 동위원소 추적자를 이용한 실험은 그 유용성에도 불구하고, 무기 질소의 안정동위원소 측정이 어려워 자료의 생산이 활발하지 못한 형편이다. Gardner et al. (1996)은 HPLC (high performance liquid chromatography)를 이용하여 비교적 간편하고 정밀하게 암모늄의 동위원소 비를 측정하는 방법을 개발해 질소순환 연구에 활발하게 활용하였다. 그러나 일반적이지 않은 syringe 펌프가 필요해 다른 실험실에 이 시스템이 도입되지는 못하였다. 본 연구에서는 최신 HPLC 펌프 기술을 활용하여 Dr. Gardner 그룹 이후 최초로 암모늄 동위원소비 측정 시스템을 구축하였다. 표준시료 측정 결과 RTS (retention time shift)는 안정동위원소 비와 좋은 상관관계를 보였다. 이 시스템은 측정 자료를 디지털 형태로 변환하는 장치까지 갖추어 컴퓨터 프로그램을 이용한 다양한 자료처리가 가능하다. 특히 Matlab$^{(R)}$ 이용하여 retention time 계산에 peak 면적을 이용함으로써 측정의 정확성을 높이고, 직선성을 향상할 수 있었다. 영산강 하구 해수를 가지고 실시한 $^{15}N$-암모늄 첨가 실험에서 $^{15}N/^{14}N$ 비율 변화를 HPLC-RTS법을 통해 측정하였으며, 식물성 플랑크톤에 의한 암모늄 섭취와 재광물화 과정을 각각 독립적으로 측정하는 것이 가능했다.

• Journal of Chest Surgery
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• 제20권1호
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• pp.112-127
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• 1987

Myasthenia gravis is a neuromuscular transmission function disorder characterized by fatigue and weakness of voluntary muscles. This muscular weakness is intensified by activity and stress, and improved by the use of anticholinesterase compounds. It was initially described by Erb in 1879 and later named myasthenia gravis by Jolly in 1895. Although the pathogenesis is Known to be an autoimmune related reduction in the number of available acetylcholine receptors at neuromuscular junctions, the role of thymus in myasthenia gravis is still unclear and under investigation. Thymectomy in the management of myasthenia gravis has become increasingly important since Dr. Blalock observed in 1939 that some patients with thymic tumors and myasthenia gravis improved following thymectomy. A clinical study of 102 cases of myasthenia gravis was performed at Yonsei University College of Medicine. Seoul, Korea from Jan. 1976 to Jun. 1986. In order to determine which factors are of prognostic significance, attention is focused upon pre-operative patient evaluation, problems in operative and post-operative care, and long-term follow-up observations. The results were as follows: 1. The sex distribution was 67 females and 35 males, the mean age of onset was 28.95*1.69 years, and the maximal incidence occurred between 21 and 40 years of age [56 cases: 54.9%]. 2. Clinical manifestations of ocular symptoms were seen to 70 patients [68.6%] extremities weakness in 33 [32.3%], bulbar weakness in 29 [28.4%], and dyspnea in 13 [12.7%]. 3. Study cases more than two thirds were classified as mild types [MG 1 and MG 11A] and 6 cases as grave [MG 1V] based on the modified Osserman`s classification system, 4. Thymectomy was performed in 19 cases which presented in severe myasthenia symptoms and showed no improvement with cholinergic drugs. Histologic examination of the excised thymus glands revealed no abnormalities in 4 cases, thymic hyperplasia in 5, benign thymoma in 5, and malignant thymoma in 5. 5. Immediate post-operative complications included 2 cases of pneumothorax which were treated by tube thoracostomies, there was no operative mortality. 6. The response to cholinergic drugs in 36 cases younger than 20 years old and in 27 cases older than 40 years was relatively poor, while that in 35 cases between the ages of 21 and 40 years old was good. 7. Thirty of 39 cases in groups IIB, III & IV improved markedly with medical or surgical management while only 16 of 59 cases in the mild groups [I and IIA] improved, almost all surgical cases improved in all categories. 8. There were 5 deaths. occurring between 7 months and 3 years 3 months of treatment of myasthenia gravis. The causes of death were myasthenic crisis in 2 cases, respiratory failure due to candidiasis & radiation pneumonitis in one case, cerebral hemorrhage due to high blood pressure in two case.

• 터널과지하공간
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• 제15권1호
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• pp.28-38
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• 2005

근래에 들어 진행된 시추공을 이용한 각종 측정 장비의 개발에 따라 지하정보의 가시화는 중요한 관심의 초점으로 대두되었다. 이를 위해 시추공벽 영상의 모니터링과 동시에 여러 가지 분석틀을 제공할 수 있는 장비가 개발되고 있으나 불량한 암반조건이나 소수의 엔진이어만이 접근할 수 있는 곳에서는 그 장비의 활용이 극히 제한적이다. 그리하여 최소한의 기능만을 보유하고 휴대가 가능한 시추공 카메라가 개발되어 상용화 되고 있다. 본 연구에서는 휴대용 시추공 카메라를 이용하여 얻은 지하정보를 토대로 암반 내에 발달해있는 불연속면의 분포를 3차원으로 가시화 하는 수리학적인 형식화 과정과 가시화된 이미지의 해석방법을 제시하고 이에 대한 사례연구로서 두 지역에 적용하였다. 형식화 과정은 3차원 공간좌표에서 불연속면의 방향성분(경사각, 경사방향 및 심도)이 지시한 위치관계를 시추공의 선주향(trend)와 주향경사(plunge)의 변화에 기초하여 고찰함을 의미하며, 그 결과 일련의 조건식을 유도한다. 두 지역에 대한 사례연구를 통해, 본 연구에서 제시한 가시화 기법이 국지적인 불연속면의 분포가 중요한 경우 지반공학적(geotechnical)으로 유용한 수단이 될 수 있음을 알 수 있다.

• Journal of Nutrition and Health
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• 제25권6호
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• pp.429-449
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• 1992

The consumption of foods rich in TDF should not be associated with impaired mineral absorp-tion and long-term mineral status. In surveys of populations consuming high amounts of TDF e.g Third World populations and vegetarinas gross deficiencies in mineral nutrition have not been noted. If mineral status is low among these groups it is most likely caused by the inadequacy or imbalance of the diet and not by the TDF. The key word is interaction which should be inte-rpreted in dietary imbalances that produce nut-rient deficiencies. There are no strong data to support the concept that TDF inhibits mineral absorption through a binding chelation mechanism. Limited data sug-gest that positively charged groups on polymers such as chitosan and cholestyramine will decrease iron absorption in humans and animals. Because TDF does not contain positively charged groups future research should be directed at the possible role of protein consumed along with TDF and the combination of effects on mineral nutrition Phytic acid is acknowledged as a potent chela-tor of zinc. However its association with zinc and its propensity to lower Zn bioavaiability may enhance the absorption of other elements notably copper and iron. The importance of interactions among nutrients including TDF will gain addi-tional attention in the scientific community. Soluble and insoluble dietary fiber function di-fferently in the intestine. Insoluble fibers accele-rate movement through the intestine. Soluble die-tary fibers appear to regulated blood concentra-tions of glucose and cholesterol albeit by some unknown mechanism. In creased viscosity produ-ced by the SDF in the intestine may provide an explanation of how this class of polymers affects plasma glucose cholesterol and other nutrients. Employing a double-perfusion technique in the rat we demonstrated that viscosity produced by SDF will delay transfer of zinc into the circulatory system. This delayed absorption should not be interpreted as decreased utilization. A great deal of additional research is required to prove the importance of luminaly viscosity produced by SDF on slowing nutrient absorption or regulating bllod nutrient homeostasis. Increased intake of TDF in the total human diet appears desirable. A dietary intake of 35g/day should not be considered to have a negative effect on mineral absorption. It is important to educate people that an intake of more than 35g TDF/day may cause an imbalance in the diet that can adve-rsely affect mineral utilization. Acknowledgments. Appreciation is given to Dr. George V. Vahouny(deceased) who was intense a great competitor in and out of science and who gave the author inspiration Portions of this work were supported by the University of Missouri Ag-ricultural Station and by a grant from the Univer-rch Support Grant RR 07053 from the National Institutes of Health. Contribution of the Missouri Agriculatural Experiments Station Journal Series No. 10747.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2006년도 추계학술발표회
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• pp.253-258
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• 2006

본 연구는 우리나라 RCC/RSC의 효율성을 2개의 입력변수와 5개의 출력변수를 자료를 토대로 퍼지 DEA를 이용하여 측정 평가하였다. 특히, 본 연구에서는 해양사고 발생자료 뿐만 아니라 환경스트레스치에 의한 잠재적 해양사고 발생가능 자료도 고려하여 운영효율성을 분석하였다. 한편, 현실자료에는 수많은 애매성이 존재하기 때문에 본 연구에서는 DEA법에 퍼지이론을 이용한 퍼지 DEA 법을 이용하였다. 이 퍼지 DEA법은 ${\alpha}-cut$ 을 기반으로 한 크리습 선형계획문제로 변환된 것으로 입/출력 변수를 삼각형 퍼지수로 하여 해를 산출하는 방법을 제안하였고, 제안된 퍼지 DEA를 이용하여 퍼지 RCC/RSC의 순위를 결정하였다. ${\alpha}-cut$를 0.5 로 하여 효율성을 산출한 결과 YS, BS, MP, TS, JJ, PH, US, IC, SC, DH, GS, TA, WD RCC/RSC 순으로 효율성 이 높게 나타났다. 따라서 효율성이 비교적 낮게 평가된TA, WD RCC/RSC는 효율성이 높은 준거집단을 참조하여 벤치마킹을 해야할 필요가 있다.