• 대한영상의학회지
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• 제81권5호
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• pp.1194-1203
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• 2020

목적 본 연구의 목적은 수술 전 표재성 방광암(T1 또는 그 이하 병기)을 확인하기 위한 자기공명영상의 stalk sign 및 inchworm sign의 진단적 능력을 평가하는 것이다. 또 다른 목적은 두 sign 간의 진단적 능력의 차이를 비교하는 것이다. 대상과 방법 방광전절제술을 시행 받은 총 240명의 환자들(505개의 종양들)을 후향적으로 검토하였다. 모든 종양은 3.0 테슬러 자기공명영상에서 T2 강조영상의 stalk sign 또는 확산강조영상의 inchworm sign을 발견함으로써 표재성 종양 및 침윤성 종양으로 분류하였다. 이를 수술 후 병리학적 T 병기와 비교함으로써 통계학적으로 진단적 의의를 평가하였고 두 sign 간의 진단적 능력 차이를 비교하였다. 결과 Stalk sign 및 inchworm sign은 높은 특이도(93%, 91%), 양성예측도(89%, 90%), 정확도(70%, 74%)를 보였으나 낮은 민감도(54%, 61%)와 음성예측도(60%, 63%)를 보였다. 두 sign 간의 진단적 능력에서 통계학적 유의미한 차이는 없었다(p > 0.05). 결론 수술 전 T2 강조영상의 stalk sign과 확산가중영상의 inchworm sign을 발견함으로써 표재성 방광암을 쉽게 진단할 수 있다.

• 대한족부족관절학회지
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• 제12권2호
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• pp.163-167
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• 2008

Purpose: To evaluate the incidence of avascular necrosis (AVN), prognostic reliability of the Hawkins sign, and clinical outcomes after operative treatment of fracture and dislocations of the talar neck. Materials and Methods: We analysed 16 patients with fracture and dislocations of the talar neck which were treated by open reduction and internal fixation and followed up for more than 2 years. The postoperative radiographs were examined for Hawkins sign and avascular necrosis was confirmed by bone scan. The assessment of clinical results was based on the Hawkins scoring system. Results: AVN was occurred in 2 of 16 cases (12.5%) only in type III. Hawkins sign was found 11 of 16 cases (68.8%), which included 8 cases in type II, 2 cases in type III and 1 case in type IV. The Hawkins sign was not observed in two cases with AVN. In contrast, only 2 of the 5 cases with a negative Hawkins sign developed AVN. According to Hawkins scoring system, 4 patients (25.0%) was in excellent, 7 patients (43.8%) in good, 4 patients (25.0%) in fair and 1 patient (6.3%) in poor. Conclusion: Incidence of AVN after operative treatment of fracture and dislocations of the talar neck was lower than that of previous reports. Hawkins sign had a high prognostic reliability, but absence of Hawkins' sign should not be considered a totally reliable indicator of development of avascular necrosis.

• 대한전자공학회논문지TC
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• 제45권8호
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• pp.69-74
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• 2008

본 논문에서는 유전율($\varepsilon'$)과 투자율($\mu'$)이 양수인 double-positive (DPS) 물질에서 정의된 전파 상수를 epsilon-negative(ENG) 물질 (${\varepsilon}'<0,\;{\mu}'>0$), mu-negative (MNG) 물질 (${\varepsilon}'>0,\;{\mu}'<0$), 그리고 double-negative (DNG) 물질 (${\varepsilon}'<0,\;{\mu}'<0$)으로 확장하여 유도하였다. 이와 함께 유전율 손실(${\varepsilon}"$)과 투자율 손실(${\mu}"$)이 전파 상수에 미치는 영향을 분석하여 이 물질에서 전파가 right-handed (RH) 혹은 left-handed (LH)로 동작하는지를 규명하였다. DPS와 DNG 물질은 ${\varepsilon}"$와 ${\mu}"$의 값에 상관없이 각각 RH 그리고 LH 매질로 동작한다. 반면 ENG와 MNG 물질은 (${\varepsilon}'{\mu}"+{\varepsilon}"{\mu}'$)의 부호가 양수이면 RH, 음수이면 LH 매질로 동작하는 특이한 특성을 가진다.

• Bulletin of the Korean Chemical Society
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• 제29권4호
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• pp.851-855
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• 2008

The reactions of O,O-diphenyl Z-S-phenyl phosphorothiolates with X-pyridines have been studied kinetically in acetonitrile at $35.0{^{\circ}C}$. The Hammett plots for substituent (Z) variations in the leaving group (log $k_2$ vs. $\sigma$ Z) are biphasic concave downwards with breaks at Z = H. The large magnitudes of ${\rho}X(\rho_{nuc})$, ${\beta}X(\rho_{nuc})$, and the cross-interaction constant, $\rho$XZ, suggest frontside nucleophilic attack toward the leaving group. The sign reversal of $\rho$Z from positive in $\sigma$ Z $\leq$ 0 to negative in $\sigma$ Z $\geq$ 0 is interpreted as the change in mechanism from concerted to stepwise with rate-limiting expulsion of the leaving group. The anomalous negative sign of $\rho$ Z for leaving groups with electron-withdrawing substituents is interpreted as the intramolecular ligand exchange process of the leaving group from the equatorial position in the intermediate to the apical position in the TS.

• 천문학회지
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• 제36권spc1호
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• pp.7-12
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• 2003

We have studied the magnetic helicity of active regions by using the data from (1) the photo-electric magnetograph of the Okayama Observatory (1983-1995) and (2) the video magnetograph of NAOJ/Mitaka (1992-2000). The latitude distribution of helicity showed a tendency that the regions in the north (south) hemisphere have negative (positive) helicities, respectively, which is already known as the hemispheric sign rule. If we look into the sign of helicity as a function of time, the sign rule was less definite or was reversed sometimes in the sunspot minimum phase. We also studied the relation between the magnetic helicity and the sunspot tilt angles, and found that these two quantities are positively correlated, which is opposite to the expectation of a theoretical model. The implications of this cycle-phase dependence of helicity signs and the correlation between magnetic he Ii city and sunspot tilt angles are discussed.

• Journal of Information Technology Applications and Management
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• 제23권3호
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• pp.87-97
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• 2016

This paper proposes a fast sound source localization method using a TDOA sign-based algorithm. We present an L-shaped microphone set-up which creates four major regions in the range of $0^{\circ}{\sim}360^{\circ}$ by the intersection of the positive and negative regions of the individual microphone pairs. Then, we make an initial source region prediction based on the signs of two TDOA estimates before computing the azimuth value. Also, we apply a threshold and angle comparison to tackle the existing front-back confusion problem. Our experimental results show that the proposed method is comparable in accuracy to previous three microphone array methods; however, it takes a shorter computation time because we compute only two TDOA values.

• 국제지역연구
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• 제14권3호
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• pp.267-289
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• 2010

본 연구는 아시아지역에서의 한국과 일본의 대 아시아지역 직접투자의 특성을 거시적 측면과 미시적 측면으로 구분하여 분석하였다. 거시적 측면에서는 시장지향적 특성과 생산효율지향적 특성이 강한지를 다중회귀분석으로, 미시적 특성으로는 투자유형(합작 단독)과 투자규모, 노동집약도, 임금, 본사 파견 노동자 비율 등의 관계를 로지스틱회귀분석으로 분석하였다. 대체로 한국은 시장지향적 및 생산효율지향적 특성에서 2000년 이후 대체로 시장지향적 특성으로 전환되었고 일본은 생산효율지향적 특성에서 2000년 이후 대체로 시장지향적 및 생산효율지향적 특성으로 전환되었다. 한편 투자유형면에서는 한국과 일본 모두 GDP가 증가할수록, 파견노동자의 비율이 높을수록 단독투자를 선호하는 경향이 높은 것으로 나타났다. 한국은 투자규모가 클수록 현지임금이 높을수록 합작투자를, 일본은 자본집약도가 높을수록 단독투자를 선호하는 것으로 나타났다.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3597-3601
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• 2013

The reactions of bis(Y-aryl) chlorothiophosphates (1) with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at $55.0^{\circ}C$. The Hammett plots for substituent Y variations in the substrates show biphasic concave upwards with a break point at Y = H. The cross-interaction constants (${\rho}_{XY}$) are positive for both electron-donating and electron-withdrawing Y substituents. The kinetic results of 1 are compared with those of Y-aryl phenyl chlorothiophosphates (2). The cross-interaction between Y and Y, due to additional substituent Y, is significant enough to result in the change of the sign of ${\rho}_{XY}$ from negative with 2 to positive with 1. The effect of the cross-interaction between Y and Y on the rate changes from negative role with electron-donating Y substituents to positive role with electron-withdrawing Y substituents, resulting in biphasic concave upward free energy correlation with Y. A stepwise mechanism with a rate-limiting leaving group departure from the intermediate involving a predominant frontside attack hydrogen bonded, four-center-type transition state is proposed based on the positive sign of ${\rho}_{XY}$ and primary normal deuterium kinetic isotope effects.

• The Journal of Asian Finance, Economics and Business
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• 제6권2호
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• pp.257-267
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• 2019

The paper aims to test long-term and short-term causality from four exchange rates, the Korean won/$US, the Korean won/Euro, the Korean won/Japanese yen, and the Korean won/Chinese yuan, to the Korea Composite Stock Price Index in the presence of several macroeconomic variables using monthly data from January 1986 to June 2018. The results of Johansen cointegration tests show that there exists at least one cointegrating equation, which indicates that long-run causality from an exchange rate to the Korean stock market will exist. The results of vector error correction estimates show that: for long-term causality, the coefficient of the error correction term is significant with a negative sign, that is, long-term causality from exchange rates to the Korean stock market is observed. For short-term causality, the coefficient of the Japanese yen exchange rate is significant with a positive sign, that is, short-term causality from the Japanese yen exchange rate to the Korean stock market is observed. The coefficient of the financial crises i.e. 1997-1999 Asian financial crisis and 2007-2008 global financial crisis on the endogenous variables in the model and the Korean economy is significant. The result indicates that the financial crises have considerably affected the Korean economy, especially a negative effect on money supply.

• Asian-Australasian Journal of Animal Sciences
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• 제17권12호
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• pp.1746-1750
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• 2004

The PBM ${BioSign}^{TM}$ Salmonella (PBMS) test kit based on an mmunochromatographic method was evaluated for the screening of Salmonella spp. in pure cultures, and 80, 15, and 10 artificially and naturally contaminated, and negative controlled food samples, respectively. The PBMS test involves presumptive qualitative procedures, detecting the presence of Salmonella spp. in foods within 26 h total testing period and allowing the user to release negative products 70 h earlier than the conventional methods. The PBMS test using Buffered Peptone Water and Rappaport-Vassiliadis broth was evaluated for 10 different food types for various Salmonella spp. It showed detection limits of 1 to 25 colony forming units (CFU)/25 g. No cross-reaction was observed, particularly to other gramnegative bacteria. These results indicate the PBMS test is a rapid and inexpensive procedure for the screening of Salmonella spp. present at low concentrations (1 to 25 CFU/25 g) in foods.