• The Korean Journal of Physiology and Pharmacology
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• v.21 no.4
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• pp.361-370
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• 2017

Previous reports have suggested that physical and psychological stresses may trigger fibromyalgia (FM). Stress is an important risk factor in the development of depression and memory impairments. Antidepressants have been used to prevent stress-induced abnormal pain sensation. Among various antidepressants, tianeptine has been reported to be able to prevent neurodegeneration due to chronic stress and reverse decreases in hippocampal volume. To assess the possible effect of tianeptine on FM symptoms, we constructed a FM animal model induced by restraint stress with intermittent cold stress. All mice underwent nociceptive assays using electronic von Frey anesthesiometer and Hargreaves equipment. To assess the relationship between tianeptine and expression levels of brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), and phosphorylated cAMP response element-binding protein (p-CREB), western blotting and immunohistochemistry analyses were performed. In behavioral analysis, nociception tests showed that pain threshold was significantly decreased in the FM group compared to that in the control group. Western blot and immunohistochemical analyses of medial prefrontal cortex (mPFC) and hippocampus showed downregulation of BDNF and p-CREB proteins in the FM group compared to the control group. However, tianeptine recovered these changes in behavioral tests and protein level. Therefore, this FM animal model might be useful for investigating mechanisms linking BDNF-CREB pathway and pain. Our results suggest that tianeptine might potentially have therapeutic efficacy for FM.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.255-255
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• 2016

Resistive random access memory (ReRAM)는 낮은 동작 전압, 빠른 동작 속도, 고집적화 등의 장점으로 인해 차세대 비휘발성 메모리 소자로써 많은 관심을 받고 있다. 최근에 ReRAM 절연막으로 NiOx, TiOx, AlOx TaOx, HfOx와 같은 binary metal oxide 물질들을 적용하는 연구가 활발히 진행되고 있다. 특히, HfOx는 안정적인 동작 특성을 나타낸다는 점에서 ReRAM 절연막 물질로 적합하다고 보고되고 있다. ReRAM 절연막을 형성할 때, 물리 기상 증착 방법 (PVD)이나 화학 기상 증착법 (CVD)과 같은 방법이 많이 이용된다. 이러한 증착 방법들은 고품질의 박막을 형성시킬 수 있는 장점이 있다. 하지만, 높은 온도에서의 공정과 고가의 진공 장비가 이용되기 때문에 경제적인 문제가 있으며, 기판 또는 금속에 플라즈마 손상으로 인한 문제가 발생할 수 있다. 따라서 이러한 문제점들을 개선하기 위해 용액 공정이 많은 관심을 받고 있다. 용액 공정은 공정과정이 간단할 뿐만 아니라 소자의 대면적화가 가능하고 공정온도가 낮으며 고가의 진공장비가 필요하지 않은 장점을 가진다. 따라서 본 연구에서는, 용액공정을 이용하여 HfOx 기반의 ReRAM 제작하였고 $25^{\circ}C$와 $85^{\circ}C$에서 ReRAM의 동작특성에 미치는 compliance current의 영향을 평가하였다. 실험 방법으로는, hafnium chloride (0.1 M)를 2-methoxyethanol에 충분히 용해시켜서 precursor를 제작하였다. 이후, p-type Si 기판 위에 습식산화를 통하여 300 nm 두께의 SiO2 절연층을 성장시킨 후, 하부전극을 형성하기 위해 electron beam evaporation을 이용하여 10/100 nm 두께의 Ti/Pt 전극을 증착하였다. 순차적으로, 제작된 산화물 precursor를 이용하여 Pt 위에 spin coating 방법으로 1000 rpm 10 초, 6000 rpm 30초의 조건으로 두께 35 nm의 HfOx 막을 증착하였다. 최종적으로, solvent 및 불순물을 제거하기 위해 $180^{\circ}C$의 온도에서 10 분 동안 열처리를 진행하였으며, 상부 전극을 형성하기 위해 electron beam evaporation을 이용하여 Ti와 Al을 각각 50 nm, 100 nm의 두께로 증착하였다. ReRAM 동작에서 compliance current가 미치는 영향을 평가하기 위하여 compliance current를 10mA에서 1mA까지 변화시키면서 측정한 결과, $25^{\circ}C$에서는 compliance current의 크기와 상관없이 일정한 메모리 윈도우와 우수한 endurance 특성을 얻는 것을 확인하였다. 한편, $85^{\circ}C$의 고온에서 측정한 경우에는 1mA의 compliance current를 적용하였을 때, $25^{\circ}C$에서 측정된 메모리 윈도우 크기를 비슷하게 유지하면서 더 우수한 endurance 특성을 얻는 것을 확인하였다. 결과적으로, 용액공정 방법으로 제작된 ReRAM을 측정하는데 있어서 compliance current를 줄이면 보다 우수한 endurance 특성을 얻을 수 있으며, ReRAM 소자의 전력소비감소에 효과적이라고 기대된다.

• Annual Conference on Human and Language Technology
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• 1997.10a
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• pp.469-476
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• 1997

본 연구는 한글 전용과 한자 혼용이 글의 이해 속도, 이해 정도, 내용의 기억에 어떤 영향을 미치는 가를 조사하기 위해 실시되었다. 한글 전용론과 한자 혼용론은 각각 나름대로의 논리를 가지고 서로 논쟁을 펼쳐왔다. 먼저 한글전용론의 주장을 살펴보면, 한자는 배우기 어렵고 쓰기도 불편해 쉽게 익힐 수 있는 한글을 사용해야 하며, 한자를 사용함으로 인해서 순 우리말의 발전이 방해를 받고, 글자 생활의 기계화와 출판 문화의 발달에 있어 한자는 이것을 어렵게 한다는 것이다. 반면에, 한자혼용론의 주장에 따르면, 한자말은 한자로 적을 때 그 의미의 파악이 빠르고 정확하고, 우리말 어휘의 절반 이상을 한자어가 차지하고 있으므로 한자를 가르치는 것이 국어교육의 지름길이고, 우리말에는 동음이의어가 많아서 한글로만 적을 경우 그 뜻을 식별하기 어렵고, 한자는 각 글자가 모두 뜻을 가지고 있으므로, 각각을 조합하여 새로운 의미의 단어를 쉽게 만들 수 있음은 물론이고 한글로 쓸 경우 길게 쓰여져야만 하는 것을 짧게 쓸 수 있다는 장점을 가지고 있으며, 한자를 쓰지 않으면 우리의 전통 문화를 이어 받을 수 없으며 한자를 공통으로 쓰고 있는 동양문화권에서도 고립을 초래할 수 있다는 것이다. 이렇게 한글전용과 한자혼용에 대한 의견이 다양한 만큼 우리나라의 한자에 대한 정책도 그 갈피를 잡지 못하고 계속 바뀌어 왔다. 독립이후 정부에서는 법령과 훈령 등으로 모든 공문서에서의 한자사용을 금지하고 일반 사회의 문자 생활에도 한글을 전용할 것을 권고하지만 이 지침은 결국 공문서에만 한정되어 왔고 후에는 이것조차도 유명무실해졌다. 또한 중고등학교의 한자교육 정책도 수차례 변화되어 한글만을 배운 세대가 사회에 나와 여전히 한자가 사용되고 있어 적응에 문제점을 가지기도 하였다. 본 연구에서는 그 동안 계속되어 온 한글과 한잔의 사용에 관한 논쟁을 언어심리학적인 연구 방법을 통해 조사하였다. 즉, 글을 읽는 속도, 글의 의미를 얼마나 정확하게 이해했는지, 어느 것이 더 기억에 오래 남는지를 측정하여 어느 쪽의 입장이 옮은 지를 판단하는 것이다. 실험 결과는 문장을 읽는 시간에서는 한글 전용문인 경우에 월등히 빨랐다. 그러나. 내용에 대한 기억 검사에서는 국한 혼용 조건에서 더 우수하였다. 반면에, 이해력 검사에서는 천장 효과(Ceiling effect)로 두 조건간에 차이가 없었다. 따라서, 본 실험 결과에 따르면, 글의 읽기 속도가 중요한 문서에서는 한글 전용이 좋은 반면에 글의 내용 기억이 강조되는 경우에는 한자를 혼용하는 것이 더 효율적이다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.8
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• pp.615-623
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• 2018

The probability density function(PDF) for the amplitude of the reflectivity of low-grazing-angle sea clutter has generally been modeled by a compound-Gaussian distribution, rather than by the Rayleigh distribution, owing to the intensity variation of each clutter patch over time. The texture component forming the reflectivity has been simulated by combining Gamma distribution and memory-less nonlinear transformation(MNLT). On the other hand, there is no typical method available that can be used to simulate the speckle component. We first review Watt's method, wherein the speckle is simulated starting from the Doppler spectrum of the received echoes that is modeled as having a Gaussian shape. Then, we introduce a newly proposed method. The proposed method simulates the speckle by manipulating a clutter covariance matrix through the Cholesky decomposition after minimizing the effect of adjacent clutter patches using an equalizer. The feasibility of the proposed method is validated through simulation, wherein the results from two methods are compared in terms of the Doppler spectrum and the correlation function.

• Journal of Life Science
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• v.25 no.9
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• pp.1043-1050
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• 2015

Glutamate is one of the principle transmitters in the CNS. Ionotropic receptors of glutamate, selectively activated by N-methyl-D-aspartate (NMDA), play an important role in the processes of cell development, learning, memory, and etc. On the other hand, many studies discovered that over-activation of glutamate receptors leads to neurodegeneration and are known to be implicated in major areas of brain pathology. Any sustained effect of a transient NMDA receptor activation is likely to involve signaling to the nucleus and to trigger coordinated changes in gene expression. Classically, a set of immediate-early genes are induced first; some of genes are by themselves transcription factors that control expression of other target genes. This study provides understanding of changes of inducible transcription factors mRNA levels with RT-PCR by inducing over-activation of NMDA receptor with intraperitoneal NMDA injection. The experimental conditions were varied by 1, 5, 25, and 125 g/ of body weight NMDA and measured transcription factors mRNA levels are Egr-1, c-Jun, JunB, and FosB. Based on result obtained, inducible transcription factors mRNA in NMDA injection to mice with 5 g/body weight showed the greatest change. And ITF mRNA showed greatest change 24 hr after injection. The expression level of JunB mRNA was markedly changed. Up to the present days, no study clearly understood how ITF mRNA affected the apoptosis of purkinje cells in the cerebellum. The current study improves the understanding of the mechanism of apoptosis of purkinje cells in the cerebellum.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.637-642
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• 2004

Effects of defatted sesame and perilla methanol extracts on cognitive function and antioxidant activity of learning- and memory-impaired animal model SAMP8 mice. Animals were divided into 4 groups and fed with diets containing 0.3%(w/w) defatted sesame (S) or defatted perilla methanol extracts (P) for 12 weeks. Step through latency of SAMP8 control group was significantly higher than that of SAM R1 normal group, whereas significantly increased in S and P groups compared with SAMP8 control on passive avoidance test (p<0.001). Acetylcholinesterase activity of brain in SAMP8 increased compared with SAMR1 but no difference between SAMP8 control group and sample-treated group. Brain TBARS contents of SAMP8 control significantly increased compared with SAMR1 and were lowered significantly by supplementation of defatted sesame and perilla methanol extracts. Defatted sesame and perilla methanol extracts attenuated increased brain superoxide dismutase and glutathione peroxidase activities in SAMP8. These results suggest defatted sesame and perilla methanol extracts could attenuate cognitive deficits induced by aging possibly through activation of antioxidant activity of defatted sesame and perilla methanol extracts.

• Korean Journal of Biological Psychiatry
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• v.8 no.1
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• pp.85-95
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• 2001

This study was designed to examine the effects of two antidepressant drugs on the expression of c-fos mRNA in cultured embryonic rat hippocampal neurons. The drugs used were imipramine and amitriptyline. On the fourth day of culture, hippocampal neurons were treated with variable concentrations of each drug. Competitive RT-PCR(Reverse Transcriptase-PCR) analysis was used to quantify the c-fos mRNA expression induced by each drug. Experimental results showed that acute and direct treatment with imipramine and amitriptyline with relatively low concentrations(imipramine ${\leq}10{\mu}M$, amitriptylne ${\leq}10{\mu}M$) had no inductive effect on the expression of c-fos mRNA in the rat hippocampal neurons. However, after treatment with relatively high concentrations(imipramine ${\geq}100{\mu}M$, amitriptyline ${\geq}100{\mu}M$) c-fos mRNA was not detected. These findings suggest the followings. Firstly, the action mechanisms of these drugs on the hippocampal neurons might not be mediated by c-fos but by other immediate-early genes(IEGs). Secondly, their actions may be mediated indirectly via other areas of the brain. Thirdly, the expression of c-fos might be inhibited by high concentrations of these drugs, or the high concentrations could induce cell death. Finally, though cell death remains to be confirmed, the inhibition of c-fos induction or cell death could play a role in the cognitive impairments known to be adverse effects of some antidepressants. This study is believed to be a first step toward understanding the mechanisms of learning and memory. Further studies are needed to investigate the expression of various IEGs and changes in the hippocampal neurons of rat resulting from chronic treatment with antidepressant drugs.

• Journal of Oriental Neuropsychiatry
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• v.19 no.3
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• pp.69-84
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• 2008

Objective: This experiment was designed to investigate the effects of the KBHT hot water extract & ultra-fine powder on Alzheimer's Disease Model Induced by $\beta$A. Method: The effects of the KBHT hot water extract on expression of proinflammatory cytokine mRNA in BV2 microglial celll cell line treated by lipopolysacchaide(LPS). The effects of the KBHT hot water extract & ultra-fine powder on (1) the behavior (2) AChE in serum (3) the infarction area of the hippocampus, and brain tissue injury in Alzheimer's diseased mice induced with $\beta$A were investigated. Results: 1. The KBHT hot water extract suppressed the expression of proinflammatory cytokine mRNA in BV2 microglial cell line treated with LPS. 2. The KBHT hot water extract & ultra-fine powder a significant inhibitory effect on the memory deficit was shown for the mice with Alzheimer's disease induced by $\beta$A in the Morris water maze experiment, which measured stop-through latency and distance movement-through latency 3. The KBHT hot water extract & ultra-fine powder suppressed the over-expression of AChE activity in the serum of the mice with Alzheimer's disease induced by $\alpha$A. 4. The KBHT hot water extract & ultra-fine powder suppressed the expression of TNF-$\alpha$, IL-l$\beta$ protein significantly in the microglial cell of mice with Alzheimer's disease induced by 1$\beta$A. 5. The KBHT ultra-fine powder reduced infarction area of hippocampus significantly in the mice with Alzheimer's disease induced by $\beta$A. Conclusions: These results suggest that the KBHT hot water extract & ultra-fine powder may be effective for the prevention and treatment of Alzheimer's disease. Investigation into the clinical use of the PMCMT hot water extract & ultra-fine powder for Alzheimer's disease is suggested for future research.

• Culinary science and hospitality research
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• v.17 no.3
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• pp.20-32
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• 2011

The purpose of this study is to analyze customers' behavior in using word-of-mouth(WOM) information about Korean local food restaurants. The questionnaire developed for this study was distributed to 500 customers living in Jeonbuk area and a total of 455 copies (91.0%) were used for analysis. The statistical analysis was conducted using SPSS Win(12.0). The results were summarized as follows. The recommendation of people experienced'($M=3.57{\pm}1.24$) and 'word-of-mouth through people around'($M=3.52{\pm}1.20$) were major word-of-mouth information sources of Korean local foods; 'taste of food'($M=4.16{\pm}1.15$) and 'service quality'($M=3.79{\pm}1.11$) were important attributes in word-of-mouth information. In addition, to the question about the reasons for recommending the restaurant to the people around, the most people replied that 'flavor, nutrition and quality of local foods can be kept only in the specific location' ($3.53{\pm}1.08$), followed by 'to keep the memory of the visit to the areas in mind through local foods'($3.51{\pm}1.03$). These results showed that people usually recommend a restaurant based on the quality of the food itself or local characteristics. As a result, it is deemed that word-of-mouth effect is an important factor for the spread of Korean local foods.

• Korean Journal of Cognitive Science
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• v.27 no.2
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• pp.275-301
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• 2016

Attentional blink (AB) refers to the phenomena where conscious report for a target (T2) subsequent to the first target (T1) in a stream of items under rapid serial visual presentation (RSVP) becomes difficult if the T2 follows no later than 500ms after the T1. The present study examined the effect of T1 visibility on T2 AB strength according to the bottleneck account proposing that the amount of allocated resources for T1 memory consolidation determines the strength of AB against T2. In the low-visibility condition, the T1 had a gray color for a low stimulus contrast against the black background whereas had a bright and saturated color in the high-visibility condition. In both visibility conditions, the T1 was also highly distinct from the remaining distractors. A multi-RSVP method was also used for increasing location uncertainty of the targets supposedly consuming on average attentional resources for the targets. Two experiments revealed that AB strength was more intense in the low-visibility than high-visibility condition, and the pattern of difference went more pronounced if T2 visibility was improved. The results indicate that T1 visibility can affect more strongly when attentional resources are relatively lacking for resolving the T1 bottleneck, and support for the bottleneck account proposing that the level of T1's visibility can determine the intensity of the T1 bottleneck.