• 대한핵의학회지
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• 제30권4호
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• pp.502-506
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• 1996

연구 목적 : 디피리다몰 부하-휴식 Tc-99m MIBI 일일 심근영상법에서 부하기 영상이 정상인 환자에서 휴식기 영상이 필요한지 알아보고자 하였다. 대상 및 방법 : 흉통을 주소로 전남대학교병원을 내원하여 핵의학과에서 디피리다몰 부하/휴식 MIBI 심근관류 SPECT를 시행한 환자 중 부하시 스캔 소견상 관류결손이 없었고, 심근관류검사 전후 1개월 이내에 관동맥조영술로 관동맥병변 유무가 확진된 43명의 환자(남:여=24:19, 평균연령 $52{\pm}11세$)를 대상으로 하였다. 촬영방법은 디피리다몰 부하-휴식 Tc-99m MIBI 일일 심근영상법을 사용하였다. 결과 및 결론 : 부하기 영상이 정상인 환자 중 관동맥질환이 없는 경우 휴식기에도 정상으로 나올 확률은 79% (23/29)였고, 새로운 관류결손이 나올 확률은 21%였다. 부하기 영상이 정상이면서 관동맥질환이 있는 환자에서 휴식기 영상으로 새로운 결손을 찾아낼 확률은 22%였다. 따라서, 흉통을 호소하는 환자에서 부하기 영상이 정상일때 휴식기 영상은 대체로 추가적인 정보를 주지 못한다는 것을 알 수 있었다. 그러나, 관동맥경련이 있는 환자는 5명 중 4명(80%)에서 휴식기 영상에 새로운 관류결손이 보일 수 있으므로, 관동맥경련이 의심되는 환자에서는 휴식기 영상을 촬영할 필요가 있을 것으로 사료되었다.

• 생태와환경
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• 제41권4호
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• pp.472-484
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• 2008

The calibrated Andong Reservoir hydro-dynamic module (PART I) of the 2-dimensional hydrodynamic and water quality model, CE-QUAL-W2 [v3.2], was applied to examine the dynamics of total phosphorus, and chlorophyll $\alpha$ concentration within Andong Reservoir. The modeling effort was supported with the data collected in the field for a five year period. In general, the model achieved a good accuracy throughout the calibration period for both chlorophyll ${\alpha}$ and total phosphorus concentration. The greatest deviation in algal concentration occurred on $10^{th}$ October, starting at the layer just beneath the surface layer and extending up to the depth of 35 m. This deviation is principally attributed to the effect of temperature on the algal growth rate. Also, on the same date, the model over-predicts hypolimnion and epilimnion total phosphorus concentration but under-predicts the high concentrated plume in the metalimnion. The large amount of upwelling of finer suspended solid particles, and re-suspension of the sediments laden with phosphorus, are thought to have caused high concentration in the epilimnion and hypolimnion, respectively. Nevertheless, the model well reproduced the seasonal dynamics of both chlorophyll a and total phosphorus concentration. Also, the model tracked the interflow of high phosphorus concentration plume brought by the turbid discharge during the Asian summer monsoon season. Two different hypothetical discharge scenarios (discharge from epilimnetic, and hypolimnetic layers) were analyzed to understand the response of total phosphorus interflow plume on the basis of differential discharge gate location. The simulated results showed that the hypolimnetic discharge gate operation ($103{\sim}113\;m$) was the most effective reservoir structural control method in quickly discharging the total phosphorus plume (decrease of in-reservoir concentration by 219% than present level).

• 대한핵의학회지
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• 제20권2호
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• pp.73-78
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• 1986

Of 18 patients with Takayasu's arteritis who underwent $^{99m}Tc-MAA$ (macroaggregated albumin) perfusion luing scanning, 9 (50%) showed perfusion defects. Chest X-rays of them were nonspecific. One patient underwent $^{99m}Tc-DTPA$ radio aerosol inhalation lung scanning simultaneously, which revealed normal. So routine screening radioisotope perfusion lung scanning is helpful to evaluate pulmonary arterial involnmement in Takayasu's arteritis patients. And Takayasu's arteritis should be included in differential diagnosis of pulmonary embolism.

• The Korean Journal of Physiology and Pharmacology
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• 제16권2호
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• pp.79-89
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• 2012

We examine whether Phellodendron amurense (PA) and its major alkaloid compound, berberine (BER), improved memory defects caused by administering scopolamine in rats. Effects of PA and BER on the acetylcholinergic system and pro-inflammatory cytokines in the hippocampus were also investigated. Male rats were administered daily doses for 14 days of PA (100 and 200 mg/kg, i.p.) and BER (20 mg/kg, i.p.) 30 min before scopolamine injection (2 mg/kg, i.p.). Daily administration of PA and BER improved memory impairment as measured by the passive avoidance test and reduced the escape latency for finding the platform in the Morris water maze test. Administration of PA and BER significantly alleviated memory-associated decreases in cholinergic immunoreactivity and restored brain-derived neurotrophic factor and cAMP-response element-binding protein mRNA expression in the hippocampus. PA and BER also decreased significantly the expression of proinflammatory cytokines such as interleukin-$1{\beta}$, tumor necrosis factor-${\alpha}$ and cyclooxygenase-2 mRNA in the hippocampus. These results demonstrated that PA and BER had significant neuroprotective effects against neuronal impairment and memory dysfunction caused by scopolamine in rats. These results suggest that PA and BER may be useful as therapeutic agents for improving cognitive functioning by stimulating cholinergic enzyme activity and alleviating inflammatory responses.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2007년도 추계학술발표회
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• pp.177-183
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• 2007

제어봉이 부착된 원관 후류의 유동특성을 관찰하기 위해 입자영상유속계(PIV)를 사용한 계측을 수행하였다. 실험은 소형회류수조에서 유업 유속을 0.lm/s, 0.2m/s, 0.4 m/s 로 하고, 원관(D=50mm) 에 제어봉이 없는 경우와 제어봉이 5mm, 10mm, 20mm 가 부착된 총 l27가지로 정하였고, 속도신호에 따른 주파수특성을 고찰하였다. 실험에서 제어봉의 영향으로 인하여 와류흘림 주파수가 작게 나타났으며, 유동제어의 지배변수로는 d/D와 레이놀즈수이며, 원관 후류의 주파수특성에 큰 영향을 미쳤다. 와류흘림 주파수는 제어봉이 0.20인 경우 가장 작게 나타났다.

• 천문학회보
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• 제35권2호
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• pp.33.1-33.1
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• 2010

We investigate the relation between the presence of bars in galaxies and AGN activities. Bars are believed to play an important role in fueling of AGN. Although there have been many previous studies on this topic, "the AGN-Bar Connection" is still an open question. To better understand the connection, we use a volume-limited sample of 9,726 late-type galaxies brighter than $M_r$=-19.5+5logh at $0.02{\leqq}z{\leqq}0.05489$, drawn from SDSS DR7. Among galaxies in the sample, 1,963 galaxies are classified as AGN-host galaxies based on the emission-line ratios while barred galaxies are identified by visual inspection. The bar fraction in AGN host galaxies (22.5%) is 3-times higher than in star-forming galaxies (8.6%). However, this trend is simply caused by the fact that the bar fraction increases with galaxy mass or luminosity and that AGN host galaxies are on average more massive than star-forming galaxies. Nevertheless, we find that among AGN host galaxies, the bar fraction increases with the Eddington ratio $(L_{[OIII]}/M_{[BH]})$, and this trend remains intact even at fixed galaxy luminosity and stellar velocity dispersion. These results imply that bars play a role in triggering AGNs.

• 대한기계학회논문집A
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• 제38권4호
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• pp.437-442
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• 2014

원자력 발전소의 터빈-발전기 시스템과 같이 일정한 토크와 함께 축 진동에 의한 가변 응력이 인가되는 부재의 경우 비틀림 응력에 의한 피로 파괴 거동을 보인다. 따라서 본 연구에서는 터빈-발전기의 터빈 축에 인가하는 비틀림 응력을 측정하고 응력에 의해 발생하는 피로 파괴 거동을 분석하는 것을 목적으로 하였다. 이를 위해 터빈-발전기 시스템과 같은 실험 장치를 제작하고 임의의 부하를 인가하여 다양한 비틀림 응력에 대한 피로 파괴 거동을 평가하였다. 특히 기존의 알려진 피로 거동 평가 방법인 응력-수명, 변형률-수명, 균열성장 평가 방법을 동시에 적용하여 평가를 진행하였다. 부하의 크기가 증가하면서 평가 방법과 무관하게 피로 수명이 감소하는 경향이 확인하였으며 5 kV 부하 인가 시 최대 10배의 피로 수명의 감소가 발생하였다.

• 대한핵의학회지
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• 제32권4호
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• pp.391-395
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• 1998

목적 : 방사성스트론튬은 핵사고시 방사성옥소, 방사성세슘 등과 더불어 환경 중으로 다량이 방출되어 환경 및 인체를 오염시키는 방사독소 중의 하나이다. 본 실험에서는 분자량이 서로 다른 카이틴 3종, 카이토산 3종, 인산카이토산 1종 등의 천연착화제와 EDTA, DTPA 등의 화학적착화제를 컬럼크로마토그래피 방법을 통해 방사성스트론튬에 대한 착화율을 비교하였다. 대상 및 방법: 실험에 사용한 카이틴 및 카이토산, 인산카이토산, EDTA, DTPA은 모두 수용성으로 생리식염수에 녹여 0.01% 상태로 만들어 사용하였으며, 컬럼은 PD-10 Sephadex G-25 M을 사용하였다. 착화물 형성비율은 전체 분획의 방사능 중 착화물의 분획이 차지하는 비율(%)로 산출하였다. 결과: 카이틴, 카이토산, 인산카이토산과 같은 천연착화제나 EDTA, DTPA 등의 화학적착화제 모두 pH 3, 5, 7에서 평균 90% 이상의 높은 착화율을 나타내었는데, 통계적으로 유의한 차이는 없었다. 결론: 천연착화제인 카이틴, 카이토산은 화학적착화제와 차이가 없이 방사성스트론튬에 대해 우수한 착화율을 보이므로, 무독성인 점을 감안한다면 방사성스트론튬 오염에 실제적으로 사용할 수 있는 착화제라고 사료된다.

• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.708-720
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• 2012

In this study, we assessed the effects of ginsenoside Re (GRe) administration on repeated immobilization stress-induced behavioral alterations using the forced swimming test (FST), the elevated plus maze (EPM), and the active avoidance conditioning test (AAT). Additionally, we examined the effect of GRe on the central adrenergic system by observing changes in neuronal tyrosine hydroxylase (TH) immunoreactivity and brain-derived neurotrophic factor (BDNF) mRNA expression in the rat brain. Male rats received 10, 20, or 50 mg/kg GRe (i.p.) 30 min before daily exposures to repeated immobilization stress (2 h/day) for 10 days. Activation of the hypothalamic-pituitary-adrenal (HPA) axis in response to repeated immobilization was confirmed by measuring serum levels of corticosterone (CORT) and the expression of corticotrophin-releasing factor (CRF) in the hypothalamus. Repeated immobilization stress increased immobility in the FST and reduced open-arm exploration in the EPM test. It also increased the probability of escape failures in the AAT test, indicating a reduced avoidance response. Daily administration of GRe during the repeated immobilization stress period significantly inhibited the stress-induced behavioral deficits in these behavioral tests. Administration of GRe also significantly blocked the increase in TH expression in the locus coeruleus (LC) and the decrease in BDNF mRNA expression in the hippocampus. Taken together, these findings indicate that administration of GRe prior to immobilization stress significantly improved helpless behaviors and cognitive impairment, possibly through modulating the central noradrenergic system in rats. These findings suggest that GRe may be a useful agent for treating complex symptoms of depression, anxiety, and cognitive impairment.

• Journal of Acupuncture Research
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• 제18권2호
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• pp.18-26
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• 2001

Purpose : To evaluate the effects of electroacupuncture on regional cerebral blood flow (rCBF) at acupoints suggested by oriental medicine to be related to the treatment of cerebrovascuiar diseases. Materials and Methods : Rest/electroaeupuncture-stimulation Tc-99m ECD brain SPECT using a same-dose subtraction method was performed on 5 normal male volunteers (age range from 27 to 30 years) using electroacupuncture at acupoint, ST 36. In the control study, needle location was chosen on a non-meridian focus 1cm posterior to the right fibular head. All images were spatially normalized and the differences between rest and acupuncture stimulation were statistically analyzed using SPM$^{(R)}$ for Windows$^{(R)}$. Results : Electroacupuncture applied at ST36 increased rCBF in the left hemisphere, that is, the left parietal lobe(angular gyrus), the left temporal lobe, the left inferior frontal lobe around rectus gyrus and the left cerebellar hemisphere, a part of the left inferior frontal lobe. In the control stimulation, no significant rCBF increase was observed. Conclusion : The results demonstrate that electroacupuncture increases rCBF in the contralateral cerebral hemisphere.