• Journal of Chest Surgery
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• 제46권2호
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• pp.117-123
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• 2013

Background: We examined perioperative predictors of sustained sinus rhythm (SR) in patients undergoing the Cox maze operation and concomitant cardiac surgery for structural heart disease. Materials and Methods: From October 1999 to December 2008, 90 patients with atrial fibrillation (AF) underwent the Cox maze operation and other concomitant cardiac surgery. Eighty-nine patients, all except for one postoperative death, were followed-up with serial electrocardiographic studies, 24-hour Holter monitoring tests, and regular echocardiographic studies. Results: Eighty-nine patients undergoing the maze operation were divided into two groups according to the presence of SR. At the time of last follow-up (mean follow-up period, $51.0{\pm}30.8$ months), 79 patients (88.8%) showed SR (SR group) and 10 patients (11.2%) had recurrent AF (AF group). Factors predictive of sustained SR were the immediate postoperative conversion to SR (odds ratio, 97.2; p=0.001) and the presence of SR at the 6th month postoperatively (odds ratio, 155.7; p=0.002). Duration of AF, mitral valve surgery, number of valves undergoing surgery, left atrial dimension, and perioperative left ventricular dimensions and ejection fractions were not predictors of postoperative maintenance of SR. Conclusion: Immediate postoperative SR conversion and the presence of SR at the 6th postoperative month were independent predictors of sustained SR after the maze operation.

• Journal of Chest Surgery
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• 제46권2호
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• pp.98-103
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• 2013

Background: Atrial fibrillation (AF) is a common complication in elderly patients with atrial septal defect (ASD). The purpose of this study was to examine the efficacy of the maze procedure in these patients. Materials and Methods: Between February 2000 and May 2011, 46 patients underwent the maze procedure as a concomitant operation with ASD closure. Three patients who underwent a right-sided maze were excluded, and one patient was lost to follow-up. The mean follow-up duration was $3.2{\pm}2.5$ years. Electrocardiography was performed 1 month, 3 months, 6 months, and 1 year after surgery, and checked annually after that. Results: AF persisted in 4 patients after surgery. One year after surgery, among 38 patients, 55.3% remained in sinus rhythm without antiarrhythmic drugs. However, when including the patients who took antiarrhythmic drugs, 92.1% were in sinus rhythm. Freedom from AF recurrence at 3 months, 6 months, 1 year, 2 years, 3 years, and 5 years after surgery were $97.4{\pm}2.6$, $94.4{\pm}3.8$, $91.2{\pm}4.9$, $87.8{\pm}5.8$, $79.5{\pm}7.6$, and $68.2{\pm}12.4$, respectively. There was no early mortality after operation. Conclusion: Concomitant treatment with the maze procedure and ASD closure is safe and effective for restoring the sinus rhythm.

• Journal of Chest Surgery
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• 제50권3호
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• pp.163-170
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• 2017

Background: The absence of atrial contraction (AC) after the maze procedure has been reported to cause subsequent annular dilatation and to increase the risk of embolic stroke. We hypothesized that the lack of AC could increase the risk of permanent pacemaker (PPM) implantation in patients undergoing the maze procedure. Methods: In 376 consecutive patients who had undergone a cryo-maze procedure and combined valve operation, recovery of AC was assessed at baseline and at immediate (${\leq}2$ weeks), early (${\leq}1$ year, $4.6{\pm}3.8$ months), and late (>1 year, $3.5{\pm}1.1$ years) postoperative stages. Results: With a median follow-up of 53 months, 10 patients underwent PPM implantation. Seven PPM implants were for sinus node dysfunction (pauses of $9.6{\pm}2.4$ seconds), one was for marked sinus bradycardia, and two were for advanced/complete atrioventricular block. The median (interquartile range) time to PPM implantation was 13.8 (0.5-68.2) months. Our time-varying covariate Cox models showed that the absence of AC was a risk factor for PPM implantation (hazard ratio, 11.92; 95% confidence interval, 2.52 to 56.45; p=0.002). Conclusion: The absence of AC may be associated with a subsequent risk of PPM implantation.

• Advances in Traditional Medicine
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• 제7권1호
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• pp.41-45
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• 2007

The roots of the plant Korean ginseng have been extensively used in the traditional Chinese herbal medicine. The effects of chronic administration of Korean ginseng extract (KGE) were investigated on two different anxiety models: the elevated T-maze (for inhibitory avoidance and escape measurements) and the open field test (OFT). Diazepam (1 mg/kg), KGE (10, 30 and 100 mg/kg) were administered orally for 15 days. On the 14th day, mice were previously exposed for 30 min to one of the open arms of the T-maze, 24 h before the test. On 15th day, mice had two exposures to the enclosed and open arm of the elevated T-maze followed by exposure to the open field apparatus. The number of line crossings in the apparatus was used to assess locomotor changes. Cumulative Concentration Response Curve of 5-HT was plotted using rat fundus which were pre-treated in a similar way. Treatment with Diazepam (1 mg/kg) and KGE (10, 30 and 100 mg/kg) significantly (P < 0.05) impaired inhibitory avoidance performance but did not impair escape latency. In OFT, diazepam facilitated locomotion as compared to vehicle and other treatment groups. KGE at any of the selected doses did not impair locomotion. Concentration response curve of 5-HT was shifted towards the right with suppression of maxima in rats treated with KGE. The results suggest that KGE exerts anxiolytic like behaviour in a specific subset of defensive behaviour, particularly those related to generalized anxiety disorder.

• Journal of Chest Surgery
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• 제32권10호
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• pp.903-909
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• 1999

Background: The current study was undertaken to investigate the results of a modification in the conventional Maze III Procedure devised by the authors. The aim of the technical modification was in improving the left atrial contractility. Material and Method: Between July 1997 and December 1998, 34 patients with chronic atrial fibrillation for more than 1 year duration underwent a modified Maze III procedure. The assessment of the left atrial function was made by various echocardiographic measurements and SA nodal recovery was evaluated by HRV Holter monitoring. Result: All 34 patients were in sinus rhythm. On echocardiography, right atrial contraction was detected in 32 patients(94.1%) and left atrial contraction in 33 patients(97.1%). The echocardiographic A wave at 1, 6, and 12 months or more were 50.5$\pm$31.5, 62.1$\pm$25.1, 66$\pm$20.6 cm/sec, respectively, and the E wave measurements at the same time points were 152$\pm$31.1, 134.4$\pm$35.2, 133$\pm$27.5 cm/sec. The corresponding A/E ratios were 0.32$\pm$0.13, 0.48$\pm$0.18, 0.5$\pm$0.15, showing a rising trend. Treadmill evaluation at 6 months showed a mean 82% increase in heart rate after excising, and the SDNN and SDANN upon HRV Holter at 1 and 3 months postoperatively were 65.3$\pm$28.1/87.8$\pm$27.2 ms, and 60.0$\pm$24.1/83.4$\pm$25.7 ms, respectively, showing a predoinant autonomic recovery in the parasympathetic system(PSDNN = 0.01, PSDANN =0.015). Conclusion: The results of our data suggest that the current modification in the conventional Maze III Procedure was efective in enhancing the postoperative left atrial contractility.

• 대한한의학회지
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• 제29권5호
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• pp.67-76
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• 2008

Objectives : Amnesia is theloss or impairment of memory, caused by physical injury, disease, drugs, or emotional trauma. Recently, the average life span is increasing, while at the same time, the incidence of dementia-like diseases in conjunction with amnesia are also increasing. Therefore learning and memory are very important issues in modern society. Ancient Korean physicians used several herbs to treat dementia and these herbal effects were described in Korean herbal books. Among them are some reports on several cognitive-enhancing herbs which have since been shown to improve dementia in recent pharmacological studies, such as Panax ginseng; however, the facilitatory effects of many Korean cognitive-enhancing herbs on learning and memory are limited. Learning and memory are essential requirements for every living organism in order to cope with environmental demands; cholinergic systems are known to be involved in learning and memory. Methods : In this study, the effects of Acori graminei rhizoma (AGR, 石菖蒲) on learning and memory were investigated by Morris water maze, eight-arm radial maze, and the effects on the central cholinergic system of rats injected with scopolamine. Results : In the water maze, the experimental animals were trained to find a platform in a fixed position for 6 days and then received a 60 sec probe trial in which the platform was removed from the pool on the 7th day. In the eight-arm radial maze, the animals were tested four times per day for 6 days. Scopolamine impaired performance of the maze tests and reduced activity of acetylcholinesterase (AchE) in the hippocampus, which is a marker for the central cholinergic system. There were significant reversals from the scopolamine-induced deficits on learning and memory in these tests, through daily administrations of AGR (100 mg/kg, p.o.) over 14 consecutive days. These treatments also reduced the loss of cholinergic activity in the hippocampus induced by scopolamine. Conclusions : These results demonstrated that AGR ameliorated learning and memory deficits by affecting the central acetylcholine system.

• 한국정보통신학회논문지
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• 제18권6호
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• pp.1441-1446
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• 2014

본 논문에서는 로봇군집이 미로 탈출을 위해 협력하는 방법에 대해 제안되었다. 로봇은 센서를 통해 필수적인 데이터를 수집하고 판단하여 자율적으로 움직일 수 있다. 하지만 미로 탈출을 위해 협력하기 위해서는 중앙 시스템이 여러 로봇들을 제어할 필요가 있다. 로봇들은 보이지 않는 미로를 탐색하며, 탈출 경로를 위한 분석과 지도를 만들기 위해 이동과 같은 정보를 중앙제어시스템에 전송한다. 여러 대의 로봇들이 미로를 효과적으로 탈출하기 위해서, 이 논문에서는 다음과 같은 문제를 고려하였다. 첫째, 로봇들이 미로 영역을 나누어서 탐색하기. 둘째, 벽으로 막혀 있는 막다른 골목을 찾아서 다른 로봇이 진입하지 못하도록 하기. 셋째, 목적지에 먼저 도착한 로봇이 최단 경로를 만들어 다른 로봇이 빨리 탈출할 수 있도록 하기. 위의 3가지를 고려하여 미로 동시 탈출을 위한 알고리즘을 구현하여 다양한 미로 크기별로 실험하였다.

• 정보교육학회논문지
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• 제13권1호
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• pp.69-76
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• 2009

본 논문에서는 레고 마인드스톰 NXT라는 로봇을 활용하여 프로그래밍을 재미있게 수업할 수 있는 방안에 대해서 모색하였다. 수업의 목표는 단편적인 지식 습득이 아닌 미로찾기라는 문제해결을 목표로 한다. 이 로봇은 컴퓨터에 설치된 NXT-G라는 GUI와 USB를 통해서 통신을 하도록 되어있다. 이 GUI는 텍스트 기반 방식이 아닌 아이콘 기반 방식 프로그래밍 도구이다. 본 논문에서는 16주를 초급 단계, 중급 단계, 고급단계로 나누어서 계획하였다. 초급 단계에서는 GUI 사용 방법과 로봇의 센서들의 작동방법을 익히는 것에 주안점을 두었다. 중급 단계에서는 저(低)난이도 미로를 설계하여 프로그래밍하는 단계로 구성하였다. 고급 단계에서는 중(中)난이도와 고(高)난이도의 미로를 설계하여 프로그래밍하는 단계로 구성하였다. 모든 미로찾기 문제는 알고리즘 작성, 순서도 작성, 스택을 이용한 프로그래밍이라는 3가지 과정을 거치도록 구성하였다.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4167-4173
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• 2010

2005년에 개정된 ICT교육지침에는 전 학교급에 걸쳐서 알고리즘, 자료구조, 프로그래밍 내용과 같은 컴퓨터 과학 요소가 매우 강화되었다. 컴퓨터교육의 목표가 소프트웨어 활용보다 문제해결력 향상이기 때문이다. 그래서 본 논문에서는 이러한 요소에 대한 학습방법의 일환으로서 로봇들이 협동을 통하여 미로를 탈출하는 문제를 해결할 수 있는 방안을 제시하였다. 로봇이 해결해야하는 문제로서 우선탐색 문제와 역할바꿈 문제와 같이 2가지를 제시하였다. 우선탐색 문제는 첫 번째 로봇이 미로를 끝까지 탐색하면서 미로의 정보를 두 번째 로봇에게 실시간으로 전송한다. 그 후 슬레이브 로봇은 이 정보를 이용하여 탐색없이 미로를 탈출하게 된다. 역할바꿈 문제는 첫 번째 로봇이 미로를 탐색하는 도중 그 기능을 상실했을 때, 두 번째 로봇이 첫 번째 로봇의 역할을 이어받아 수행하는 것이다. 각 문제를 해결하기 위해서 문제분석, 알고리즘 기술, 순서도 작성, 프로그래밍의 4단계를 거치도록 하였다. 본 논문에서 제시한 내용의 부수적인 효과로는 로봇협동을 통한 학습자들의 협동학습 기회 제공, 로봇간 데이터 송수신을 위해서 큐(queue)라는 자료구조를 사용했다는 점이다. 향후에는 좀 더 일반적인 미로의 사용, 실제 현장에의 적용, 영재교육 과정에의 적용에 대한 연구가 필요하다.

• Animal cells and systems
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• 제6권4호
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• pp.287-292
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• 2002

Functional characterization of sex pheromones in olfactory responses is essential for the study of chemical communications in amphibians. Using Y-maze olfactory preference tests, we have investigated the olfactory res-ponses of male and female red-spotted newts, Notophthalmus viridescens, to the crude extracts of the opposite sex's genial and cloacal pheromones. Both male and female cloacal pheromone extracts caused the opposite sex to initiate olfactory responses by leaving the starting area in the Y-maze, but only subject males exposed to female cloacal pheromone extracts completed olfactory choice by entering the side arm of the Y-maze which received the pheromones. For genial pheromone extracts, only female genial pheromone extracts induced initial olfactory responses from test males. Neither male nor female genial pheromone extracts made the oppo-site sex complete olfactory choice. Pre-exposure of test females to male pheromone extracts increased the likelihood of initial olfactory responses. The latency for initial olfactory responses of test females that were previously exposed to male genial extracts was significantly shorter than that of control females.