• Investigative Magnetic Resonance Imaging
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• 제22권1호
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• pp.65-70
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• 2018

The objective of this study was to describe a radiofrequency (RF) coil design for in vivo sodium magnetic resonance imaging (MRI) for use in small animals. Accumulating evidence has indicated the importance and potential of sodium imaging with improved magnet strength (> 7T), faster gradient, better hardware, multi-nucleus imaging methods, and optimal coil design for patient and animal studies. Thus, we developed a saddle-shaped sodium volume coil with a diameter/length of 30/30 mm. To evaluate the efficiency of this coil, bench-level measurement was performed. Unloaded Q value, loaded Q value, and ratio of these two values were estimated to be 352.8, 211.18, and 1.67, respectively. Thereafter, in vivo acquisition of sodium images was performed using normal mice (12 weeks old; n = 5) with a two-dimensional gradient echo sequence and minimized echo time to increase spatial resolution of images. Sodium signal-to-noise ratio in mouse kidneys (renal cortex, medulla, and pelvis) was measured. We successfully acquired sodium MR images of the mouse kidney with high spatial resolution (approximately 0.625 mm) through a combination of sodium-proton coils.

• 의학교육논단
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• 제19권2호
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• pp.90-100
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• 2017

The necessity of embracing selective courses in medical curriculum is increasing due to the expansion of medical knowledge and changes in the health care environment. In contrast to the abundant evidence regarding elective or selective courses during the clinical phase, articles focusing on the preclinical period are relatively scarce. This study aims to explore the development, implementation, and evaluation of newly-adopted selective courses in the first-year medical curriculum in a medical school which recently underwent a major curricular revision. First of all, the Curriculum Committee established goals and operating principles of the courses, and then the committee encouraged all participating professors to attend a related faculty development workshop after finalizing the list of courses. A survey was conducted at the end of each course for evaluation. Of the 36 courses opened in 2016, the overall satisfaction of students was $4.98{\pm}1.06$ (out of 6) and showed a strong correlation with students' previous expectations, reasoning- and participation-oriented teaching, and outcome of the courses including increased motivation. In the open-ended responses, students and professors described not only intended outcomes such as acquisition of medical knowledge and increased interest in new topics, but also unintended outcomes including positive impression for selective courses and even high satisfaction and rewarding experiences, especially from the teachers' perspective. Although long-term outcomes remain to be seen, the results of this study show the feasibility and impact of selective courses and will contribute to effective implementation in other medical schools.

• 재무관리연구
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• 제8권1호
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• pp.139-153
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• 1991

미국의 증권거래법규(證券去來法規)에서는 기업의 내부자(內部者)는 자기주식(自己株式)의 주거상황(去來狀況)을 차월 10일 이내에 증권거래위원회(證券去來委員會)(SEC)에 보고하도록 규정하고, 특히 기업합병(企業合倂)에 관한 내부정보(內部情報)가 공표되기 전에는 주식거래를 일체 금하고 있다. 최근 SEC가 일부 내부자 및 투자전문가들이 기업 합병에 관한 내부정보를 입수해서 이를 이용한 불법적인 거래를 행하여 막대한 수익을 취득했다고 발표함으로서 내부자거래(內部者去來)에 대한 관심은 한층 더 고조되었다. 1970년대 발표된 내부자거래(內部者去來)에 관한 연구는 그 초점을 주식시장(株式市場) 효율성(效率性)에 두었다. 예를 들면, Jaffe는 SEC에서 매월 발간되고 있는 기업내부자들의 거래상황을 보고한 Official Summary of Security Transactions and Holdings 자료를 이용하여 이들의 투자성과(投資成果)를 분석한 결과 내부자들이 상당한 초과수익율(超過收益率)(abnormal return)을 실현하고 있음을 수익 발견함으로서 국내의 증시가 강형효율성(强型效率性)에 못 미친다는 결론을 내렸다. 기존 문헌과는 달리 본 논문에서는 내부거래가 수동적(受動的)인 주식투자자(株式投資者)의 부(富)에 미치는 영향을 분석하는 데 연구의 초점을 두고 있으며, 본 연구에 사용된 자료는 거래의 불법성을 SEC가 보도하기 전까지는 공개되지 않았으며 또 표본주식들은 모두 비합병회(非合倂會)들이다. 분석결과에 의하면 관련주식의 비정상수이익율(非正常收益率)은 불법거래당일의 평균이 1.4%이고, 거래주변일에는 비정상수익율(非正常收益率)이 나타나지 않고 있다. 이 연구결과는 내부정보 수입경쟁이 치열함을 간접적으로 나타내고 있으며, 내부정보 불법거래가 투자자에게 미치는 단기적인 영향은 부정적이 아님을 표시한다.

• 식물조직배양학회지
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• 제27권4호
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• pp.339-343
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• 2000

When plants are exposed to subfreezing temperatures ice crystals are forming within extracelluar space in leaves. The growth of ice crystal is closely related to the degree of freezing injury. It was shown that an antifreeze protein binds to an ice nucleator through hydrogen bonds to prevent growth of ice crystal and also reduces freezing damage. The antifreeze proteins in plants are similar to PR proteins but only the PR proteins induced upon cold acclimation were shown to have dual functions in antifreezing as well as antifungal activities. Three of the genes encoded for CLP, GLP, and TLP were isolated from barley and Kentucky bluegrass based on amino acid sequence revealed after purification and low temperature-inducibility as shown in analysis of the protein. The deduced amino acid of the genes cloned showed a signal for secretion into extracellular space where the antifreezing activity sup-posed to work. The western analysis using the antisera raised against the antifreeze proteins showed a positive correlation between the amount of the protein and the level of freeze tolerance among different cultivars of barely. Besides it was revealed that TLP is responsible for a freeze tolerance induced by a treatment of trinexapac ethyl in Kentucky bluegrass. Analysis of an overwintering wild rice, Oryza rufipogon also showed that an acquisition of freeze tolerance relied on accumulation of the protein similar to CLP. The more direct evidence for the role of CLP in freeze tolerance was made with the analysis of the transgenic tobacco showing extracellular accumulation of CLP and enhanced freeze tolerance measured by amount of ion leakage and rate of photosynthetic electron transport upon freezing. These antifreeze proteins genes will be good candidates for transformation into crops such as lettuce and strawberry to develop into the new crops capable of freeze-storage and such as rose and grape to enhance a freeze tolerance for a safe survival during winter.

• Environmental Analysis Health and Toxicology
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• 제30권sup호
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• pp.7.1-7.10
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• 2015

Objectives For successful adoption of legislation controlling registration and assessment of chemical substances, it is important to obtain sufficient toxicological experimental evidence and other related information. It is also essential to obtain a sufficient number of predicted risk and toxicity results. Particularly, methods used in predicting toxicities of chemical substances during acquisition of required data, ultimately become an economic method for future dealings with new substances. Although the need for such methods is gradually increasing, the-required information about reliability and applicability range has not been systematically provided. Methods There are various representative environmental and human toxicity models based on quantitative structure-activity relationships (QSAR). Here, we secured the 10 representative QSAR-based prediction models and its information that can make predictions about substances that are expected to be regulated. We used models that predict and confirm usability of the information expected to be collected and submitted according to the legislation. After collecting and evaluating each predictive model and relevant data, we prepared methods quantifying the scientific validity and reliability, which are essential conditions for using predictive models. Results We calculated predicted values for the models. Furthermore, we deduced and compared adequacies of the models using the Alternative non-testing method assessed for Registration, Evaluation, Authorization, and Restriction of Chemicals Substances scoring system, and deduced the applicability domains for each model. Additionally, we calculated and compared inclusion rates of substances expected to be regulated, to confirm the applicability. Conclusions We evaluated and compared the data, adequacy, and applicability of our selected QSAR-based toxicity prediction models, and included them in a database. Based on this data, we aimed to construct a system that can be used with predicted toxicity results. Furthermore, by presenting the suitability of individual predicted results, we aimed to provide a foundation that could be used in actual assessments and regulations.

• Genomics & Informatics
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• 제6권1호
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• pp.32-35
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• 2008

Little evidence supports the existence of imprinted genes in chicken. Imprinted genes are thought to be intimately connected with the acquisition of parental resources in mammals; thus, the predicted lack of this type of gene in chicken is not surprising, given that they leave their offspring to their own heritance after conception. In this study, we identified several imprinted genes and their orthologs in human, mouse, and zebrafish, including 30 previously identified human and mouse imprinted genes. Next, using the HomoloGene database, we identified six orthologous genes in human, mouse, and chicken; however, no orthologs were identified for SLC22A18, and mouse Ppp1r9a was not included in the HomoloGene database. Thus, from our analysis, four candidate chicken imprinted genes (IGF2, UBE3A, PHLDA2, and GRB10) were identified. To expand our analysis, zebrafish was included, but no probe ID for UBE3A exists in this species. Thus, ultimately, three candidate imprinted genes (IGF2, PHLDA2, and GRB10) in chicken were identified. GRB10 was not significant in chicken and zebrafish based on the Wilcoxon-Mann-Whitney test, whereas a weak correlation between PHLDA2 in chicken and human was identified from the Spearman's rank correlation coefficient. Significant associations between human, mouse, chicken, and zebrafish were found for IGF2 and GRB10 using the Friedman's test. Based on our results, IGF2, PHLDA2, and GRB10 are candidate imprinted genes in chicken. Importantly, the strongest candidate was PHLDA2.

• 대한한의학회지
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• 제28권2호통권70호
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• pp.1-12
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• 2007

Objective : Gagamchongmyung-tang is clinically one of the most popular prescriptions as an herbal medicine for the treatment of amnesia. In order to evaluate its neuroprotective effects on the ischemia-induced cognitive deficits caused by middle cerebral artery occlusion (MCAO), we examined its ability to reduce impairments of learning and memory of rats in the Morris water maze. Method and Result : Focal cerebral ischemia produced a decrease in acetylcholine transmission in the hippocampus, and deficits of learning and memory in the Morris water maze task. Treatment with two types of Gagamchongmyung-tang, methanol and water extracts, produced a substantial increase in acquisition in the Morris water maze. Treatment with methanol extract of Gagamchongmyung-tang increased the performance of the retention test in the Morris water maze. Consistent with behavioral data, immunohistochemical data showed that treatment with methanol extract, but not water extract, of Gagamchongmyung-tang significantly recovered reduction of AchE and ChAT reactivity in the hippocampal CAl area. Conclusion : These results demonstrated that methanol extract of Gagamchongmyung-tang has protective effects against ischemia-induced learning and memory impairments, and provided evidence of methanol extract of Gagamchongmyung-tang as a putative treatment for amnesia, vascular dementia, and longer memory.

• 대한한의학회지
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• 제23권2호
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• pp.125-138
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• 2002

Learning and memory are essential requirements for every living organism in order to cope with environmental demands, and cholinergic systems are known to be involved in learning and memory. Scutellaria baicalensis (SB) and Gastrodia elata (GE) as a traditional Oriental medicine have been clinically used to treat or prevent memory deficits, including Alzheimer's disease. In the present study, we investigated the effects of SB and GE on learning and memory in the Morris water maze task and the central cholinergic system of the rats with excitotoxic medial septum lesions. In the water maze test, the animals were trained to find a platform at a fixed position over 6 days and then received a 60-s probe trial in which the platform was removed from the pool on the 7th day. Ibotenic lesion of the medial septum (MS) impaired their performance in the maze test (latency of acquisition test on the 3rd day, $27.6{\pm}$4.4 sec vs. $61.7{\pm}17.7$ sec; retention test, $7.9{\pm}1.3%$ vs. $5.7{\pm}1.0%$: sharn vs. ibotenic lesioned groups, respectively) and reduced choline acetyltransferase (ChAT) - immunoreactivity in the MS and the hippocarnpus, which is a marker for degeneration of the central cholinergic system (number of cells, $21.1{\pm}1.1$ vs. $13.2{\pm}1.3$: sham vs. ibotenic lesioned group). Daily administrations of SB (100mg/kg, p.o.) and GE (100mg/kg, p.o.) for 21 consecutive days produced significant reversals of ibotenic acid-induced deficit in learning and memory. These treatments also reduced the loss of cholinergic immunoreactivity in the MS and the hippocarnpus induced by ibotenic acid. These results demonstrated that SB and GE ameliorated learning and memory deficits through effects on the central nervous system, partly through effect on the acetylcholine system. Our studies suggest an evidence of SB and GE as treatment for Alzheimer's disease.

• 대한의용생체공학회:의공학회지
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• 제36권4호
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• pp.95-102
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• 2015

Epilepsy is a chronic neurological disease which produces repeated seizures. Over 30% of epileptic patients cannot be treated with anti-epileptic drugs, and surgical resection may cause loss of brain functions. Seizure suppression by electrical stimulation is currently being investigated as a new treatment method as clinical evidence has shown that electrical stimulation to brain could suppress seizure activity. In this paper, design of a real-time closed-loop neurostimulation system for epileptic seizure suppression is presented. The system records neural signals, detects seizures and delivers electrical stimulation. The system consists of a 6-channel electrode, front-end amplifiers, a data acquisition board by National Instruments, and a neurostimulator and Generic Osorio-Frei algorithm was applied for seizure detection. The algorithm was verified through simulation using electroencephalogram data, and the operation of whole system was verified through simulation and in- vivo test.

• 생명과학회지
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• 제19권1호
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• pp.138-146
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• 2009

마늘은 역학조사에 의하면 각종 질환의 예방과 치료에 효능이 있는 것으로 알려져 있다. 마늘의 주요 성분인 알리신 성분은 매우 불안정하여 쉽게 분해되어 새로운 형태의 유황 화합물로 만들어져 이들 성분들이 상승적으로 작용하여 중요한 생리황성을 갖는 것으로 알려져 있다. 시판되고 있는 여러 종류의 마늘제품 중에서 숙성마늘제품이 다른 제품에 비하여 생리활성이 높은 것으로 보고되었다. 숙성마늘제품은 마늘을 일정한 조건으로 숙성시킬 때 수용성 성분인 S-allylcysteine, S-allylmercaptan, steroid saponins, te-trahydro-${\beta}$-caboline derivatives 및 fructeosyl-arginine 등이 많이 증가하여 그 효능이 상승적으로 높아지는 것으로 알려져 있다. 따라서 시판 마늘가공품의 품질을 표준화하기 위하여 이들 수용성 성분을 biomarker로서 규격기준을 정해야 할 것이다.