• Development and Reproduction
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• v.7 no.2
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• pp.89-93
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• 2003

The present study observed the ultrastructure of testis of bluespotted mud hopper(Boleophthalmus pectinirostris), and sperrnatogenesis was discussed also. The testis was surrounded by a thin adventitia, inside which spermatocyst composed the parenchyma of testis. Each lobule was enwrapped by many spermatocysts, which were filled with different kinds of spermatogenic cell clusters at the same developmental stage. In the lobule lumen there are large numbers of spermatozoa The thin adventitia(outer wall) of testis was composed of outer epithelium, and the underlying layers, such as collagen fiber layer, and myoid tissue. The myoid tissue elongated into the inside of testis, became the main componentof interstitium between spermatocyst where sperrnatogenesis occurred. In addition interstitial cells containing dense homogeneous nucleus and abundant mitochondria were observed. Spermatogonia contained round nucleus with diffuse chromatin and nucleolus, and dense nuclear bodies surround by mitochondria in cytoplasm. The synaptonemal . complex was observed in primary spermatocytes clearly. Early spermatid presented larger round nucleus composed of granular chromatin, which was located in the center of cytoplasm. The nucleus of mid-spermatid composed of finely granular chromatin lied on one side of spermatid, and abundant mitochondria had migrated another side. A nuclear fossa appeared in the site near mitochondria in late-spermatid, and the centriole was formed in nuclear fossa.

• The Korean Journal of Nuclear Medicine
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• v.39 no.6
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• pp.413-420
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• 2005

Purpose: Neuroreceptor PET studies require 60-120 minutes to complete and head motion of the subject during the PET scan increases the uncertainty in measured activity. In this study, we investigated the effects of the data-driven head mutton correction on the evaluation of endogenous dopamine release (DAR) in the striatum during the motor task which might have caused significant head motion artifact. Materials and Methods: $[^{11}C]raclopride$ PET scans on 4 normal volunteers acquired with bolus plus constant infusion protocol were retrospectively analyzed. Following the 50 min resting period, the participants played a video game with a monetary reward for 40 min. Dynamic frames acquired during the equilibrium condition (pre-task: 30-50 min, task: 70-90 min, post-task: 110-120 min) were realigned to the first frame in pre-task condition. Intra-condition registrations between the frames were performed, and average image for each condition was created and registered to the pre-task image (inter-condition registration). Pre-task PET image was then co-registered to own MRI of each participant and transformation parameters were reapplied to the others. Volumes of interest (VOI) for dorsal putamen (PU) and caudate (CA), ventral striatum (VS), and cerebellum were defined on the MRI. Binding potential (BP) was measured and DAR was calculated as the percent change of BP during and after the task. SPM analyses on the BP parametric images were also performed to explore the regional difference in the effects of head motion on BP and DAR estimation. Results: Changes in position and orientation of the striatum during the PET scans were observed before the head motion correction. BP values at pre-task condition were not changed significantly after the intra-condition registration. However, the BP values during and after the task and DAR were significantly changed after the correction. SPM analysis also showed that the extent and significance of the BP differences were significantly changed by the head motion correction and such changes were prominent in periphery of the striatum. Conclusion: The results suggest that misalignment of MRI-based VOI and the striatum in PET images and incorrect DAR estimation due to the head motion during the PET activation study were significant, but could be remedied by the data-driven head motion correction.

• JOURNAL OF ELECTRICAL WORLD
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• s.350
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• pp.98-101
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• 2006

에너지요금의 인상이 잇따르고 있는 가운데‘이란발 쇼크’로 국제유가가 최근 가파른 상승세다. 하루 석유생산량이 390만 배럴로 석유수출국기구(OPEC) 중 사우디아라비아에 이어 두 번째로 큰 산유국 이란. 이 나라의 핵 개발을 둘러싼 국제적인 갈등이 원유공급 감소로 이어질 것이란 우려 때문이다. 미국을 비롯한 EU, 중국, 러시아가 이란 핵의 안보리 회부에 합의한데 따른 시장급변 상황에서 초래됐다. 여기에다 OPEC 회원국들이 지난달 31일 오스트리아 빈에서 열린 정례회의에서 하루 2800만 배럴인 현행 산유량 수준을 고수하기로 합의한 데 따른 파급도 있다. 중동지역의 지정학적인 위기로 인한 수급불안 우려가 해소되지 않고 있는데다 특히 OPEC의 증산 여력이 소진된 상태라는 관측 때문에 유가불안이 고조되고 있는 것이다. 2월초 현재 3월 인도분 서부 텍사스산 원유인 WTI는 배럴당 70달러에 육박하고 있다. 영국 런던 원유시장의 북해산 브렌트유 역시 덩달아 오름세이다. 우리나라에서 주로 수입하고 있는 중동산 두바이유 역시 마찬가지이다. 브렌트나 두바이유도 배럴당 같은 60달러 선이다. 유가 강세는 지난해 가을 허리케인 카트리나의 미국 남동부 강타로 대다수 석유시설이 파괴돼 수급난이 초래돼 WTI 기준 배럴당 한때 80달러에 육박한 이래 하락세를 보이다 이번에 다시 가파른 오름세로 돌아선 것이다.전문가들은 이 같은 유가의 가파른 돌변상황을 심각하게 받아들이고 있다. 1980년 5월 WTI 기준 최고치인 94달러까지 치솟아 오일쇼크를 유발한 국제유가. 이 즈음을 정점으로 내림세로 돌아서 걸프전90~91)으로 반짝 배럴당 50달러에 머문 적이 있다. 이를 제외하곤 1986년부터 2004년까진 10~30달러 선에서 비교적 안정세를 보이다 이후 미국의 이라크 침공을 기점으로 급상승세를 타고 왔다. 지난해 최고 80달러에까지 육박한 국제유가는 하향안정세에서 배럴당 60달러 선에서 등락을 거듭하고 있다. 이 수준도 턱없이 높은 것이다. 이 같은 고유가의 파고가 최근 들어 더욱 심상치 않다는 게 전문가들의 공통된 시각이다. 이번에‘이란발 오일쇼크’가 급습하는 것이 아닌가 하는 우려감마저 갖고 있다. 세계경제 회복세에 발목을 잡을 수도 있다고 보고 있다.본지는 이 같은 고유가의 파고를 넘는 첩경으로 저소비·고효율 기기를 앞으로는 시리즈로 소개한다.

• The Korean Journal of Zoology
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• v.39 no.1
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• pp.1-11
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• 1996

The SR 95531, a GABA antagonist was microinjected into either the pretectum nuclei (nucleus Superficialis Synencephali nSS) or the nBOR (nucleus Ectomammilaris nEM) of chickens. Monocular optokinetic nystagmus (01(N) was reorded by the search coil technique before and after unilateral intracerebral drug administration. Unilateral microinjections of SR 95531 into either the nSS or nEM induce a reversible increase of gain in OKN directed by contralateral eye for both directions of stimulation. The administration into the nSS increased directional asymmetry by increasing the T~ component velocity gain more strongly than the N-T component velocity gain. On the other hand, the unilateral administration of the drug into the nEM suppressed the diretional O1(N asymmetry by increasing the N-T component velocity gain more strongly than the T-N component velocity gain. The nSS seems especially involved in monocular OKN in response to a T-N stimulation, while the nEM seems more involved in the OKN response to N-T stimulation. These results indicate that the drug suppresses GABAergic inhibition at the mesencephalic level. The increase in gain of OKN directed by the ipsilateral eye to microinjeded nuclei could account for the strong interactions existing between these two mesencephalic structures responsible for horizontal OKN.

• Journal of Korea Water Resources Association
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• v.34 no.4
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• pp.303-316
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• 2001

In this study, Radial Basis Function(RBF) Neural Networks Model, a kind of Hybrid Neural Networks was applied to hydrological forecasting in a small watershed. RBF Neural Networks Model has four kinds of parameters in it and consists of unsupervised and supervised training patterns. And Gaussian Kernel Function(GKF) was used among many kinds of Radial Basis Functions(RBFs). K-Means clustering algorithm was applied to optimize centers and widths which ate the parameters of GKF. The parameters of RBF Neural Networks Model such as centers, widths weights and biases were determined by the training procedures of RBF Neural Networks Model. And, with these parameters the validation procedures of RBF Neural Networks Model were carried out. RBF Neural Networks Model was applied to Wi-Stream basin which is one of the IHP Representative basins in South Korea. 10 rainfall events were selected for training and validation of RBF Neural Networks Model. The results of RBF Neural Networks Model were compared with those of Elman Neural Networks(ENN) Model. ENN Model is composed of One Step Secant BackPropagation(OSSBP) and Resilient BackPropagation(RBP) algorithms. RBF Neural Networks shows better results than ENN Model. RBF Neural Networks Model spent less time for the training of model and can be easily used by the hydrologists with little background knowledge of RBF Neural Networks Model.

• Journal of Life Science
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• v.29 no.4
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• pp.436-441
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• 2019

Nelumbo nucifera, also known as sacred lotus, has mainly been used as a food throughout the Asian countries. In the present study, we prepared ethanol extracts from leaf (NL), seed (NS), and seedpod (NSP) of Nelumbo nucifera and investigated their anti-inflammatory activities in mouse macrophage RAW 264.7 cells. To evaluate the anti-inflammatory activities of NL, NS, and NSP, nitric oxide (NO) production was measured in LPS-stimulated RAW 264.7 cells. NL, NS, and NSP significantly reduced NO production in a dose-dependent manner without affecting cell viabilities. NL, NS, and NSP dramatically decreased the protein expression of pro-inflammatory genes such as iNOS and COX-2. NL, NS, and NSP also suppressed phosphorylation of MAPKs and the nuclear translocation of $NF-{\kappa}B$ p65 indicating they have their anti-inflammatory activities via regulating mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B ($NF-{\kappa}B$) pathways. In addition, we analyzed the production of reactive oxygen species (ROS) by the treatment of NL, NS, and NSP. All extracts reduced ROS production in a dose-dependent manner. And also, they increased heme oxygenase-1 (HO-1) protein expression and the nuclear translocation of nuclear respiratory factor 2 (Nrf2). In conclusion, our results suggest that Nelumbo nucifera has its anti-inflammatory activity via regulating MAPKs, $NF-{\kappa}B$, and Nrf2/HO-1 pathways.

• Journal of Aerospace System Engineering
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• v.16 no.1
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• pp.56-69
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• 2022

Various advanced countries are accelerating the competition in the development of hypersonic weapons. North Korea is on the verge of building a new submarine equipped with a submarine-launched ballistic missile (SLBM). A series of new guided missiles tests have continued due to political competition between the U.S. and China. The Republic of Korea is planning to boost its military capabilities, which involves the development of nuclear-powered submarines, light aircraft carriers, and new guided missiles. The northeast Asian region continues to be tense amid military rivalry between the Republic of Korea, North Korea, the United States, China, Russia, and Japan. Accordingly, these countries' competition to develop weapons is also at the world's highest level. In this paper, we examine the functioning of a hypersonic weapons system conduct a technical analysis of its components. In addition, we analyze the direction of military development that the Korean military wants to pursue through the recently announced mid-term defense plan. We conclude by highlighting the technical limitations and implementation strategies to overcome the development of hypersonic weapons.

• Journal of Veterinary Clinics
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• v.32 no.4
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• pp.301-307
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• 2015

The purpose of this study was to compare echocardiographic parameters of cloned beagle dogs with the previously reported reference range. Seven cloned dogs were assessed for anatomical features and cardiac function through left- and right-sided heart and right ventricle outflow tract from M-mode, 2D-mode, pulsed wave Doppler and tissue Doppler imaging. In all the cloned dogs, there were no abnormalities in anatomical structure and measurements were within the normal reference range. In addition, left- and right-sided myocardial function was within the normal reference range. Especially, pulmonary hypertension and right-sided heart failure frequently encountered in cloned animals were not recognized in cloned dogs. In conclusion, no evidence of cardiovascular dysfunction in mature cloned dogs could be identified either at birth or the growing stage in this study. Therefore, serious adverse effects of somatic cell nuclear transfer technology including transgenesis on cardiac morphology and function were not found in cloned dogs.

• Journal of Life Science
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• v.24 no.10
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• pp.1039-1045
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• 2014

This study analyzed whether human chorionic gonadotropin (hCG) induces ER stress via the IRE/XBP1 pathway in mouse Leydig tumor (mLTC-1) cells. In a previous study, we demonstrated that the unfolding protein response (UPR) plays an important role in the expression of steroidogenic enzymes by modulating the ATF6 pathway, as well as ER stress-mediated apoptosis in hCG-stimulated Leydig cells. Although UPR signaling has been reported to regulate the IRE1/XBP1 pathway, it is not known whether hCG-induced ER stress in Leydig cells can activate the pathway. To investigate the activation of the IRE1/XBP1 pathway in mLTC-1 cells after hCG treatment, we performed a Western blot analysis to detect the phospho-IRE1 protein and an RT-PCR analysis to validate splicing of XBP1 mRNA. We used ER stress-activated indicator (ERAI) constructs for monitoring the activity of IRE1 and then analyzed by fluorescence microscopy and flow cytometry. The expression levels of the phospho-IRE1 protein markedly increased in response to the hCG treatment. In the mLTC-1 cells transfected with an F-XBP1-venus/F-$XBP1{\Delta}DBD$-venus construct, the hCG treatment led to the appearance of green fluorescent cells and detectable fluorescence in the nucleus and cytosol, respectively. In addition, splicing of XBP1 mRNA significantly increased after the hCG treatment. Taken together, these results indicate that hCG-induced ER stress leads to activation of the IRE1/XBP pathway in Leydig cells.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.91-98
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• 2008

Purpose: Radio-isotopes (RI) use has been steadily developing due to industrial and technical development in the modern medical society. Particularly, popularization of domestic cyclotrons dramatically enable hospitals to produce and use diagnostic radio-isotopes. Generally, only specific facilities such as hospitals, research institutes, nuclear power plants and universities can use radio-isotopes, they are also responsible for ventilation system. The strength of radioactivity in the air is strongly regulated and controlled by korea atomic energy law in Korea Institue of Nuclear Safety (KINS), so that air radioactivity exposure can lead to environmental pollution surrounding places. In this study, we'd like to find out the investigation and the present condition of the controlled ventilation system in domestic hospitals by an emission standard from KINS, and try to reach an agreement about how to use the ventilation system. Result: Definition of filters, features and structures of pre-filters, hepa-filters, charcol filters, filter exchange procedures and precautions are explained. RI deflation concentration and filter exchange cycle have been presented as a standard prescribed in the rules of KINS. The Radiation Control Management System (RCMS) introduced by Seoul National University Bundang Hospital linking to digital pressure gauge with computer controller in another medical facilities were described in details. Conclusions: The system of medical facilities using RI has been remarkably developing in 21 century. Especially, radiation safety control system has also been grown rapidly into the subdivision, specialization, advanced technology along with international technical improvement. However, As far as current RI ventilation system is concerned, it has nothing better than doing in the past. Preferentially, to reinforce this, more sophisticated system with strict periodic filter exchange and exhaust air control guidance should be introduced by applying brilliant domestic information technology for RCMS and digital gauge method. From personal point of view as a radiation safety manager, I have provide with present problems and improvements. Futhermore, more improved guidance should be conducted.