• Journal of Korean Neurosurgical Society
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• 제29권6호
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• pp.719-724
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• 2000

Objectives : It has been reported that the presence of a pharmacologically inactive foreign substance, polystyrene latex bead, in subarachnoid space activates a non-specific immunological response and elicits arterial narrowing. Recently the activation of potassium($K^+$) channels may be of benefit in relieving cerebral vasospasm. The present study examined the effects of systemic administration of a ATP-sensitive $K^+$ channel activator, cromakalim, on the polystyrene latex bead-induced cerebral vasospasm. Methods : The spasm models similar to that caused by subarachnoid blood injection were created by injection of bead into rabbit cisterna magna. Intravenous injections of cromakalim were administered twice daily(bid) 30 minutes after induction of vasospasm. Animals were killed by perfusion-fixation 2 days after vasospasm. Basilar arteries were removed and sectioned, and the luminal cross-sectional areas were measured. Results : Injection of bead elicited an arterial constriction, reducing arterial diameter to 33.3% of resting tone. Cromakalim inhibited bead-induced constriction at a dose of 0.3mg/kg(Mann-Whitney test, p<0.01). Conclusion : These results support the concept that the cellular events triggered by inactivation of ATP-sensitive $K^+$ channels are responsible for the pathogenesis of vasospasm. The findings also indicate that cromakalim represents a potential therapeutic agents for the treatment of cerebral vasospasm.

• 한국정보통신학회논문지
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• 제5권7호
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• pp.1287-1294
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• 2001

심전도는 파형의 크기가 수 ㎷정도로 아주 작은 생체신호로서, 계측할 때 발생되는 잡음으로 인하여 해석하는데 어려움을 준다[1]. 깨끗한 파형을 얻기 위해서는 심전도 신호에 포함되어 있는 전원 잡음, 기저선 변동, 근 잡음을 제거해야 된다. 심전계에서 심전도 신호를 기록하는데 있어서 가장 큰 문제를 야기하는 부분이 기저선 변동인데 전극을 부착한 부위의 근육수축과 호흡의 리듬에 따라서 발생하게 된다. 그러한 기저선은 상하로 심하게 불규칙한 변동을 하면서 흔들리게 되어 심전도 신호를 진단하는데 어려움이 있으므로 기저선 변동을 제거하는 부분이 매우 중요하다. 본 연구에서는 실시간으로 신호처리 할 수 있는 디지털 필터를 구현함으로써 기저선 변동을 제거하는 시스템을 설계하여 환자의 심장질환을 분석하는데 응용할 수 있도록 하였다.

• Archives of Plastic Surgery
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• 제40권2호
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• pp.129-133
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• 2013

Background A pneumatic tourniquet is generally used to achieve a bloodless operation field in hand surgery. However, this has changed with tumescent solution-based wide-awake surgery. This study is a preliminary prospective case series study to elaborate the formula and indications of the tumescent technique in hand surgery without a tourniquet. Methods Seven patients (age range, 4 months to 37 years) underwent hand or upper extremity surgery for conditions such as nerve palsy, electric burn defect, fingertip injury, contracture, constriction ring syndrome, or acrosyndactyly. A "one-per-mil" tumescent solution (epinephrine 1:1,000,000+20 mg lidocaine/50 mL saline) was used to create a bloodless operating field without a tourniquet. Observation was performed to document the amount of solution injected, the operation field clarity, and the postoperative pain. Results The "one per mil" epinephrine solution showed an effective hemostatic effect. The tumescent technique resulted in an almost bloodless operation field in the tendon and in the constriction ring syndrome surgeries, minimal bleeding in the flap and contracture release surgeries, and acceptable bleeding in acrosyndactyly surgery. The amount of solution injected ranged from 5.3 to 60 mL. No patient expressed significant postoperative pain. Flap surgeries showed mixed results. One flap was lost, while the others survived. Conclusions Epinephrine 1:1,000,000 in saline solution is a potential replacement for a tourniquet in hand surgery. Further studies are needed to delineate its safety for flap survival.

• 대한기계학회논문집B
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• 제32권11호
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• pp.891-896
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• 2008

In the present computational study, simple stenotic artery models using pulsatile flow condition were investigated. A 1 Hz non-reversing sinusoidal velocity for pulsatile flow was imposed at the flow inlet and the corresponding Womersley number based on the vessel radius is 2.75. The simple stenotic geometries have been used that consist of 25%, 50% and 75% semicircular constriction in a cylindrical tube. In this paper, numerical solutions are presented for a first harmonic oscillatory flow using commercial software ADINA 8.4. As stenosis and Reynolds number increase, the maximum wall shear stress(WSS) increases while the minimum WSS decreases. As the stenotic rate increases, the pressure drop at the throat severely decreases to collapse the artery and plaque. It is found that the fluid mechanical disturbances due to the constriction were highly sensitive with rate of stenosis and Reynolds number. When Reynolds number and stenosis increase, the larger recirculation region exists. In this recirculation region the possibility of plaque attachment is increasingly higher. The present results enhance our understanding of the hemodynamics of a stenotic artery.

• Korea-Australia Rheology Journal
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• 제17권3호
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• pp.99-110
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• 2005

This work presents results of finite element analysis of isothermal incompressible creeping viscoelastic flows with the tensor-logarithmic formulation of the Leonov model especially for the planar geometry with singular comers in the domain. In the case of 4:1 contraction flow, for all 5 meshes we have obtained solutions over the Deborah number of 100, even though there exists slight decrease of convergence limit as the mesh becomes finer. From this analysis, singular behavior of the comer vortex has been clearly seen and proper interpolation of variables in terms of the logarithmic transformation is demonstrated. Solutions of 4:1:4 contraction/expansion flow are also presented, where there exists 2 singular comers. 5 different types spatial resolutions are also employed, in which convergent solutions are obtained over the Deborah number of 10. Although the convergence limit is rather low in comparison with the result of the contraction flow, the results presented herein seem to be the only numerical outcome available for this flow type. As the flow rate increases, the upstream vortex increases, but the downstream vortex decreases in their size. In addition, peculiar deflection of the streamlines near the exit comer has been found. When the spatial resolution is fine enough and the Deborah number is high, small lip vortex just before the exit comer has been observed. It seems to occur due to abrupt expansion of the elastic liquid through the constriction exit that accompanies sudden relaxation of elastic deformation.

• Molecules and Cells
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• 제40권1호
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• pp.66-72
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• 2017

Pathological hypertrophy of the heart is closely associated with endoplasmic reticulum stress (ERS), leading to maladaptations such as myocardial fibrosis, induction of apoptosis, and cardiac dysfunctions. Salubrinal is a known selective inhibitor of protein phosphatase 1 (PP1) complex involving dephosphorylation of phospho-eukaryotic translation initiation factor 2 subunit $(p-eIF2)-{\alpha}$, the key signaling process in the ERS pathway. In this study, the effects of salubrinal were examined on cardiac hypertrophy using the mouse model of transverse aortic constriction (TAC) and cell model of neonatal rat ventricular myocytes (NRVMs). Treatment of TAC-induced mice with salubrinal ($0.5mg{\cdot}kg^{-1}{\cdot}day^{-1}$) alleviated cardiac hypertrophy and tissue fibrosis. Salubrinal also alleviated hypertrophic growth in endothelin 1 (ET1)-treated NRVMs. Therefore, the present results suggest that salubrinal may be a potentially efficacious drug for treating pathological cardiac remodeling.

• 한국산림과학회지
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• 제77권1호
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• pp.53-64
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• 1988

국내(國內)에서 식재(植載)되고 있는 소나무류(類)(Hard Pine) 6종(種)과 잣나무류(類)(Soft Pine) 5종류(種類)의 Root-tip을 재료(材料)로하여 염색체(染色體)의 Long, Short arm과 총(總)길이를 측정(測定)S/L ratio를 구(求)하고 이차내착(二次猍窄)의 위치(位置)를 찾아내고 Idiogram을 도해(圖解)하여 Long arm의 Descending order의 순서(順序)가 바뀌는 Pattern을 밝혔다. 소나무속(屬)의 염색체(染色體)는 기본수(基本數)가 n=12, 길이가 거의 비슷하고 S/L ratio가 l에 가까운 M형(型)이 10개(個), SM형(型)이거나 SM형(型)에 가까운 길이가 짧은 것 2개(個)가 합(合)해서 Chromosone 1set를 구성(構成)한다. 이차내착(二次猍窄)의 수(數)와 위치(位置), Long arm의 Descending order의 순위(順位)가 바뀌는 Pattern으로 종간(種間)의 식별(識別)이 가능(可能)했고 Long arm의 Descending order Pattern을 비교분석(比較分析)함으로서 산지(産地)에 따라 종내변이(種內變異)를 인정(認定)할 수 있었다. 소나무류(類)와 잣나무류(類) group의 염색체구조상(染色體構造上)의 차이(差異)는 있었지만 외부형태적(外部形態的) 특성(特性)에 차이(差異)만큼 크지는 않았다. 염색체(染色體)는 시약(試藥)의 처리농도(處理濃度), 시간(時間)에 따라 아주 예민한 반응(反應)을 일으키므로 최우점(最遇點)을 맞추기가 어렵고 반복(反復)되는 실험(實驗)에서 정확(正確)히 동일(同一)하게 처리(處理)하기가 어렵다. 따라서 약간(若干)씩 다른 결과(結果)가 나올 수 있다. 또 preparatur 제작상(製作上)의 여러 가지 어려움 때문에 분석상(分析上)에 착오(錯誤)를 일으킬 가능성(可能性)이 있었다.

• Biomolecules & Therapeutics
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• 제24권3호
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• pp.252-259
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• 2016

Neuropathic pain is a complex state showing increased pain response with dysfunctional inhibitory neurotransmission. The TREK family, one of the two pore domain $K^+$ (K2P) channel subgroups were focused among various mechanisms of neuropathic pain. These channels influence neuronal excitability and are thought to be related in mechano/thermosensation. However, only a little is known about the expression and role of TREK-1 and TREK-2, in neuropathic pain. It is performed to know whether TREK-1 and/or 2 are positively related in dorsal root ganglion (DRG) of a mouse neuropathic pain model, the chronic constriction injury (CCI) model. Following this purpose, Reverse Transcription Polymerase Chain Reaction (RT-PCR) and western blot analyses were performed using mouse DRG of CCI model and compared to the sham surgery group. Immunofluorescence staining of isolectin-B4 (IB4) and TREK were performed. Electrophysiological recordings of single channel currents were analyzed to obtain the information about the channel. Interactions with known TREK activators were tested to confirm the expression. While both TREK-1 and TREK-2 mRNA were significantly overexpressed in DRG of CCI mice, only TREK-1 showed significant increase (~9 fold) in western blot analysis. The TREK-1-like channel recorded in DRG neurons of the CCI mouse showed similar current-voltage relationship and conductance to TREK-1. It was easily activated by low pH solution (pH 6.3), negative pressure, and riluzole. Immunofluorescence images showed the expression of TREK-1 was stronger compared to TREK-2 on IB4 positive neurons. These results suggest that modulation of the TREK-1 channel may have beneficial analgesic effects in neuropathic pain patients.

• 말소리와 음성과학
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• 제10권4호
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• pp.77-89
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• 2018

Speech articulators are coordinated for the purpose of segmental constriction in terms of a task. In particular, vertical jaw movements repeatedly contribute to consonantal as well as vocalic constriction. The current study explores vertical jaw movements in conjunction with bilabial constriction in bilabial stop /p/ in the context /a/-to-/a/. Revisiting kinematic data of /p/ collected using the electromagenetic midsagittal articulometer (EMMA) method from seven (four female and three male) speakers of Seoul Korean, we examined maximum vertical jaw position, its relative timing with respect to the upper and lower lips, and lip aperture minima. The results of those dependent variables are recapitulated in terms of linguistic (different word boundaries) and paralinguistic (different speech rates) factors as follows. Firstly, maximum jaw height was lower in the across-word boundary condition (across-word < within-word), but it did not differ as a function of different speech rates (comfortable = fast). Secondly, more reduction in the lip aperture (LA) gesture occurred in fast rate, while word-boundary effects were absent. Thirdly, jaw raising was still in progress after the lips' positional extrema were achieved in the within-word condition, while the former was completed before the latter in the across-word condition. Lastly, relative temporal lags between the jaw and the lips (UL and LL) were more synchronous in fast rate, compared to comfortable rate. When these results are considered together, it is possible to posit that speakers are not tolerant of lenition to the extent that it is potentially realized as a labial approximant in either word-boundary condition while jaw height still manifested lower jaw position in the across-word boundary condition. Early termination of vertical jaw maxima before vertical lower lip maxima across-word condition may be partly responsible for the spatial reduction of jaw raising movements. This may come about as a consequence of an excessive number of factors (e.g., upper lip height (UH), lower lip height (LH), jaw angle (JA)) for the representation of a vector with two degrees of freedom (x, y) engaged in a gesture-based task (e.g., lip aperture (LA)). In the task-dynamic application toolkit, the jaw angle parameter can be assigned numerical values for greater weight in the across-word boundary condition, which in turn gives rise to lower jaw position. Speech rate-dependent spatial reduction in lip aperture may be able to be resolved by means of manipulating activation time of an active tract variable in the gestural score level.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2006년도 동계학술연구발표회 및 자성 스핀트로닉스 국제학술대회
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• pp.8-8
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• 2006