• The Korean Journal of Physiology and Pharmacology
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• 제2권5호
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• pp.573-580
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• 1998

The study aims to identify the mechanism (s) underlying the altered vasodilatory responses of the pial artery of spontaneously hypertensive rats (SHR) under a hypothesis that calcitonin gene-related peptide (CGRP) exerts a modulator role in the autoregulation of cerebral blood flow (CBF). The animals were divided into four groups: 1) Sprague-Dawley rats (SDR), 2) Wistar rats (WR), 3) SHR with high blood pressure $(BP{\ge}150\;mmHg),$ and 4) SHR with normotensive BP $({\le}150\;mmHg).$ The lower limit of CBF autoregulation in SHR shifted to a higher BP $(82.8{\pm}9.3\'mmHg,\;P<0.05)$ than that in SDR $(58.9{\pm}5.7\;mmHg)$. In SHR, whether the BP levels were high or normotensive, the vasodilator responses to a stepwise hypotension were significantly attenuated unlike with SDR and WR. When artificial cerebrospinal fluid (CSF) containing capsaicin $(3{\times}10^{-7}\;M)$ was suffused over the cortical surface, a transient increase in pial arterial diameter was observed in the SHR with high or normotensive BP. In contrast, SDR and WR showed a large increase in diameter, and the increase was sustained for over 10 minutes. In line with these results, the basal releases of CGRP-like immunoreactivity (CGRP-LI) in the isolated pial arteries from SHR with high and normotensive BP were $12.5{\pm}1.4\;and\;9.8{\pm}2.8\;fmole/mm^2/60\;min\;(P<0.05)$, while those from SDR and WR were $25.5{\pm}3.1\;and\;24.6{\pm}3.1\;fmole/mm^2/60\;min,$ respectively. The isolated basilar arteries showed similar results to those of the pial arteries in SHR. Thus, it is summarized that, in the SHR, the reduced autoregulatory vasodilator responses to stepwise hypotension and capsaicin may be, in part, ascribed to the decreased release of CGRP from the perivascular sensory nerve fibers of the pial arteries, and that altered vasomotor activity in SHR may not be related with the hypertensive tone.

• 한국통신학회논문지
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• 제19권8호
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• pp.1595-1611
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• 1994

본 논문에서는 전자파의 전파현상의 불연속모델로서 시간영역 유한 차분법의 수치적 성질이 연구된다. 시간 공간의 차원에서 막스웰 방정식을 개구리뜀 근사식으로 나타내므로 수치적인 특성과 의존 영역의 항으로 전자파의 전파현상을 모사한다. 시간영역 유한차분법의 수치적모사과정이 기하학적으로 설명된다. 개구리뜀 근사법의 채용으로 인한 수치적인 분산현상이 예시된다. 개구리뜀 근사법을 기초로 한 시간영역 유한차분법은 원래 계산 결과만을 산출하는 모델이 아니고 묘사적인 모델이므로 전자파 전파현상에 대한 몰리적인 현상을 묘사할 뿐만 아니라 이러한 묘사직언 결과로부터 푸리에 변환을 통하여 주파수 영역에서의 결과를 추출할 수 잇는 매우 유연한 수치해석 방법이다. 그래서 본 수치해석 방법을 이용하여 WR-28과 WR-90 도파관의 E-평면 휠터와 인턱티브 아이리스의 특성성분적 결과를 포함시킨다.

• 한국수산과학회지
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• 제30권5호
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• pp.850-858
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• 1997

An antihyperlipidemic effect was observed by intraperitoneal injection of the seaweed Monostroma nitidum extract. Hyperlipidemia was induced by intraperitoneal injection of Triton WR-1339 $(60\;{\mu}g/g-body\;weight)$ into a mouse. Maximum level of blood cholesterol was reached at 20 hours after Triton injection. By simultaneous injection of the M. nitidum extract $(30\;{\mu}g/g-body\;weight)$ with the Triton into each right and left sides of the peritoneal cavity, levels of total cholesterol and low density lipoprotein were decreased to $24\%\;and\;14\%$ compared to Triton injection only. For histochemical changes, hepatic tissues obtained at 40 hours after injection of the Triton and the M. nitidum extract were fixed in fromol-calcium solution. The meshlike cytoplasms disappeared and hapatic plates were recovered in mice injected with the M. nitidum extract. Numbers of lipid drops and cholesterol particles also decreased in the portal space of the hepatic cytoplasm. This indicates that the accumulation of lipid, including cholesterol, caused by Triton was prevented by the antihyperlipidemic effect of extract from the seaweed M. nitidum.

• 한국전자파학회논문지
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• 제26권12호
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• pp.1083-1090
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• 2015

Ka 대역의 25 W급 SSPA를 제작하기 위하여 상용 $0.15{\mu}m$ GaN 공정을 이용 구동증폭기(Drive Amplifier : DRA) 및 고출력증폭기(High Power Amplifier : HPA) 초고주파 단일 집적회로(Monolithic Microwave Integrated Circuit : MMIC)를 설계 및 제작하여 특성 평가하였고, SSPA(Solid State Power Amplifier)의 주요 부속품인 MS-to-WR28 변환기 및 WR28 전력합성기를 설계 및 제작, 평가하여 Ka 대역 GaN 기반 SSPA를 제작하였다. 제작 결과, 주파수 29~31 GHz 대역에서 포화출력 44.2 dBm 이상, 전력부가효율 16.6 % 이상, 전력이득 39.2 dB의 특성을 나타내었다.

• 한국정보통신학회논문지
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• 제18권7호
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• pp.1652-1656
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• 2014

본 논문에서는 차량 충돌 방지 레이더 시스템 응용을 위하여 중심 주파수가 77 GHz인 도파관 (waveguide) 전압조정 발진기 (VCO, voltage controlled oscillator)를 구현하였다. 구현된 도파관 전압 조정 발진기는 GaAs 기반의 건다이오드 (Gunn diode)와 버랙터 다이오드 (varactor diode), 도파관 천이기 (waveguide transition), 저역 통과 필터(LPF, low pass filter) 및 공진기 (resonator) 기능을 동시에 수행하는 다이오드의 바이어스 (bias) 포스트 (post)로 구성되어진다. 77 GHz 신호는 동공 (cavity)을 38.50 GHz에서 발진하도록 설계하여 2체배된 신호를 사용하였으며 WR-12에서 WR-10으로 천이되어 출력된다. 도파관 천이기는 77 GHz의 중심주파수에서 1.86 dB의 삽입손실(insertion loss)과 -30.22 dB의 입력반사계수 (S11, input reflection coefficient) 특성을 갖는다. 제작된 도파관 전압조정 발진기는 870 MHz의 대역폭 (bandwidth)과 12.0 dBm ~ 13.75 dBm의 출력 전력 특성을 나타내었다. 위상잡음 특성은 1 MHz 오프셋 (offset)에서 -100.78 dBc/Hz의 우수한 특성을 얻었다.

• 동의생리학회지
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• 제14권2호통권20호
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• pp.215-224
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• 1999

After Triton WR-1339 (TX; 600mg/kg) intraperitoneal injection, hepatic tissues of ICR mice were intragastric injected with Hyulboochucketang extract(HCE; 3.3ml/kg/day) were observed to investigate the suppressive effect of lipid accumulation that evoke by the antihyperlipidemic effect of HCE. These hepatic tissues were fixed in fromol-calcium solution and were cryocut. These tissues stained by H&E for general morphology, sudan black B for lipid and perchloric acid-naphthoquinone(PAN) method for cholesterol. After TX treatment, the increase of hepatocyte having meshlike cytoplasm(HHMC) were shown in all hepatic lobules and the hepatic plates were disappeared in the aggregative region of HHMC. The number of blue black colored lipid drop and dark green colored asterisk shaped cholesterol particle in hepatic cytoplasm were increased and the size of lipid drop and cholesterol particle were enlarged. But, in HCE-treated mice, the HHCM were disappeared and hapatic plate were rearranged. The number of lipid drop and cholesterol particle were decreased than TX-treated mice and the size of lipid drop and cholesterol particle were diminished. As results indicated that the HCE work on the suppression of lipid accumulation in hepatic tissue of hyperlipidemic mice caused by disturbance of lipid metabolism.

• Animal Bioscience
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• 제34권2호
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• pp.185-191
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• 2021

Objective: The objective of this study was to estimate the genetic parameters for worm resistance (WR) and associated characteristics, using the linear-threshold animal model via Bayesian inference in single- and multiple-trait analyses. Methods: Data were collected from a herd of Santa Inês breed sheep. All information was collected with animals submitted to natural contamination conditions. All data (number of eggs per gram of feces [FEC], Famacha score [FS], body condition score [BCS], and hematocrit [HCT]) were collected on the same day. The animals were weighed individually on the day after collection (after 12-h fasting). The WR trait was defined by the multivariate cluster analysis, using the FEC, HCT, BCS, and FS of material collected from naturally infected sheep of the Santa Inês breed. The variance components and genetic parameters for the WR, FEC, HCT, BCS, and FS traits were estimated using the Bayesian inference under the linear and threshold animal model. Results: A low magnitude was obtained for repeatability of worm-related traits. The mean values estimated for heritability were of low-to-high (0.05 to 0.88) magnitude. The FEC, HCT, BCS, FS, and body weight traits showed higher heritability (although low magnitude) in the multiple-trait model due to increased information about traits. All WR characters showed a significant genetic correlation, and heritability estimates ranged from low (0.44; single-trait model) to high (0.88; multiple-trait model). Conclusion: Therefore, we suggest that FS be included as a criterion of ovine genetic selection for endoparasite resistance using the trait defined by multivariate cluster analysis, as it will provide greater genetic gains when compared to any single trait. In addition, its measurement is easy and inexpensive, exhibiting greater heritability and repeatability and a high genetic correlation with the trait of resistance to worms.

• 한국인터넷방송통신학회논문지
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• 제23권1호
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• pp.123-129
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• 2023

본 논문에서는 Ka대역 소형 레이다용 주파수합성 MMIC(FS MMIC)와 수신 MMIC를 개발하고 개발된 MMIC를 기반으로 소형화 된 Ka대역 주파수합성기와 수신기를 개발하였다. FS MMIC와 기저대역 신호를 수신하는 WR(wireless-receiver) MMIC는 65 nm CMOS 공정으로 제작하였고, Ka대역 신호를 수신하는 FE(front-end) MMIC는 150 nm GaN 공정으로 제작하였다. FS MMIC를 바탕으로 개발된 주파수합성기의 출력신호를 이용하여 Ka 대역 신호에 대한 주파수선형변조 파형과 펄스 파형을 측정하고 송신 파형 생성 가능성을 확인하였다. FE MMIC 및 WR MMIC로 구성된 수신기의 성능은 이득 80 dB 이상, 잡음지수 6 dB 이하, OP1dB 10 dBm 이상으로 측정되었다. 측정결과를 통해 본 논문에서 개발된 주파수합성기, 수신기는 Ka 대역 소형 레이다에 적용 가능한 것으로 판단된다.

• Safety and Health at Work
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• 제14권2호
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• pp.229-236
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• 2023

Background: In workers with moderate to severe work-related traumatic brain injury (wrTBI), this study aimed to investigate the effect of the timing of rehabilitation therapy initiation on the length of hospital stay and the factors that can influence this timing. Methods: We used data obtained from the Republic of Korea's nationwide Workers' Compensation Insurance. In the Republic of Korea, between the years 2010 and 2019, a total of 26,324 workers filed a claim for compensation for moderate to severe wrTBI. Multiple regression modeling was performed to compare the length of hospital stay according to the timing of rehabilitation therapy initiation following wrTBI. According to the timing of the initiation of rehabilitation therapy following TBI, the proportions of healthcare institutions that provided medical care during each admission step were compared. Results: The length of hospital stay for workers who started rehabilitation therapy within 90 days was significantly shorter than that for workers who started rehabilitationment were first admitted to tertiary hospitals. Approximately 39% of patients who received delayed rehabilitation treatment were first admitted to general hospitals, and 28.5% were first admitted to primary hospitals. Conclusions: Our findings demonstrate the importance of early rehabilitation initiation and that the type of healthcare institution that the patient is first admitted to after wrTBI may influence the timing of rehabilitation initiation. The results of this study also emphasize the need to establish a Worker's Compensation Insuranceespecialized rehabilitation healthcare delivery system.

• 한국산업정보학회논문지
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• 제20권1호
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• pp.43-47
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• 2015

본 논문에서는 밀리미터파 모듈 응용을 위하여 광대역 마이크로스트립-대-웨이브가이드 (WR12) 천이기가 제시된다. 대역폭의 개선을 위하여 radial 마이크로 스트립 electrical-probe가 저 손실 유기 유전체 기판 위에 설계되었다. 제안된 천이기의 삽입 및 반사손실에 대한 설계 및 측정된 특성을 나타내었다. 측정을 위한 케이블 아답터와 웨이브가이드 천이기의 손실을 고려하면, 제안된 천이기의 천이 손실이 70 및 80 GHz에서 각각 -1.88 및 -2.01 dB로 분석되었다. 제안된 천이기의 -10 dB 반사 손실 대역폭은 67GHz 에서 95 GHz로 약 26 GHz이다. 최신의 연구결과와 비교해서 대역폭에서 8.3 % 개선되었다.