• Toxicological Research
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• 제31권1호
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• pp.17-23
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• 2015

Excessive manganese (Mn) in the brain promotes a variety of abnormal behaviors, including memory deficits, decreased motor skills and psychotic behavior resembling Parkinson's disease. Hereditary hemochromatosis (HH) is a prevalent genetic iron overload disorder worldwide. Dysfunction in HFE gene is the major cause of HH. Our previous study has demonstrated that olfactory Mn uptake is altered by HFE deficiency, suggesting that loss of HFE function could alter manganese-associated neurotoxicity. To test this hypothesis, Hfe-knockout ($Hfe^{-/-}$) and wild-type ($Hfe^{+/+}$) mice were intranasally-instilled with manganese chloride ($MnCl_2$ 5 mg/kg) or water daily for 3 weeks and examined for memory function. Olfactory Mn diminished both short-term recognition and spatial memory in $Hfe^{+/+}$ mice, as examined by novel object recognition task and Barnes maze test, respectively. Interestingly, $Hfe^{-/-}$ mice did not show impaired recognition memory caused by Mn exposure, suggesting a potential protective effect of Hfe deficiency against Mn-induced memory deficits. Since many of the neurotoxic effects of manganese are thought to result from increased oxidative stress, we quantified activities of anti-oxidant enzymes in the prefrontal cortex (PFC). Mn instillation decreased superoxide dismutase 1 (SOD1) activity in $Hfe^{+/+}$ mice, but not in $Hfe^{-/-}$ mice. In addition, Hfe deficiency up-regulated SOD1 and glutathione peroxidase activities. These results suggest a beneficial role of Hfe deficiency in attenuating Mn-induced oxidative stress in the PFC. Furthermore, Mn exposure reduced nicotinic acetylcholine receptor levels in the PFC, indicating that blunted acetylcholine signaling could contribute to impaired memory associated with intranasal manganese. Together, our model suggests that disrupted cholinergic system in the brain is involved in airborne Mn-induced memory deficits and loss of HFE function could in part prevent memory loss via a potential up-regulation of anti-oxidant enzymes in the PFC.

• 대한간호학회지
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• 제49권3호
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• pp.317-328
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• 2019

Purpose: The purpose of this study was to identify the effect of ghrelin on memory impairment in a rat model of vascular dementia induced by chronic cerebral hypoperfusion. Methods: Randomized controlled groups and the posttest design were used. We established the representative animal model of vascular dementia caused by bilateral common carotid artery occlusion and administered $80{\mu}g/kg$ ghrelin intraperitoneally for 4 weeks. First, behavioral studies were performed to evaluate spatial memory. Second, we used molecular biology techniques to determine whether ghrelin ameliorates the damage to the structure and function of the white matter and hippocampus, which are crucial to learning and memory. Results: Ghrelin improved the spatial memory impairment in the Y-maze and Morris water maze test. In the white matter, demyelination and atrophy of the corpus callosum were significantly decreased in the ghrelin-treated group. In the hippocampus, ghrelin increased the length of hippocampal microvessels and reduced the microvessels pathology. Further, we confirmed angiogenesis enhancement through the fact that ghrelin treatment increased vascular endothelial growth factor (VEGF)-related protein levels, which are the most powerful mediators of angiogenesis in the hippocampus. Conclusion: We found that ghrelin affected the damaged myelin sheaths and microvessels by increasing angiogenesis, which then led to neuroprotection and improved memory function. We suggest that further studies continue to accumulate evidence of the effect of ghrelin. Further, we believe that the development of therapeutic interventions that increase ghrelin may contribute to memory improvement in patients with vascular dementia.

• International Journal of Internet, Broadcasting and Communication
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• 제13권4호
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• pp.176-184
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• 2021

This study aims to examine 1) the influence of festival emotional and function values on travelers' positive festival memory, festival attachment, and experience sharing behavior, and (2) the moderation effect of online friendship among the path. In the present study, the proposed model was developed based on the MTS from 340 collected participants who have experienced the festival held in Guangdong Province in China. The SPSS and AMOS were used for statistical analysis. The results revealed that emotional and function festival values are positively related to the positive festival memory of travelers; positive festival memory significantly influences festival attachment and experience sharing behavior of travelers. Meanwhile, festival attachment also has a significantly positive effect on the experience-sharing behavior of travelers. Moreover, the presented differential experience sharing behavior of travelers follows the level of their online friendship. Travelers with high online friendships presented higher sharing behavior than travelers with low online friendships. Depending on the results of this study, we could provide some theoretical implications for future festival research and online communication research. These results could provide some practical implications for festival managers to develop more communication strategies.

• 생물정신의학
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• 제4권2호
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• pp.237-245
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• 1997

The study was designed to evaluate the significant roles of SSRI in rat of depression model. Chronic exposure to mild unpredictable stress has been found to depress the consumption of sweet 1% sucrose solutions in the Sprague-Dawley rats. We applied the variety of 11 types of stress regimens and identified depressive behaviours(developed by Willner) in 70 Sprague-Dawley rats. Rats in experiments were stratified into 6 groups, ie ; 3 kinds of SSRI(paroxetine, fluoxetine, sertraline), clomipramine, choline and saline control. Memory function was evaluated by passive avoidance learning and retention test. The authors determined how long memory retention would remain improved with 24 hour, 1 week, 2 weeks, 3 weeks, and 4 weeks at training-testing interval in depressive states of the Sprague-Dawley rats. The results were as follows ; 1) There were no significant differences between the 6 groups at the 24 hour training-testing interval. 2) The paroxetine treated group showed significant differences from the control group at the 1 week and 2 weeks training-testing interval. 3) The paroxetine and the fluoxetine treated groups showed singificant differences from the control group at 3 week training-testing interval. 4) The paroxetine and the choline treated groups showed significant differences from the control group at 4 week training-testing interval. In summary, paroxetine had an effect on long term memory processing from 1st week to 4th week. Also, fluoxetine(at 3rd week) and choline(at 4th week) had effect on long term memory processing. Sertraline, clomipramine were ineffective on memory processing during 4 weeks observation. Possible explanations why paroxetine had early effect on memory processing than the other selective serotonin reuptake inhibitors are rapid bioavailability, which is the characteristics of pharmacokinetics of paroxetine. In clinical situation, author carefully suggest that SSRI would be beneficial to improve the memory function caused by depressive neurochemical changes.

• Journal of Ginseng Research
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• 제18권1호
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• pp.32-38
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• 1994

Male rats aged 15 months, which had been over-trained with 12 arm radial maze up to the criterion of 1 or 2 errors an average per trial, were divided into two groups and 7 months after the over-training and were studied the effect of red ginseng trial saponin fraction (PT) on the spatial memory function. The rats which could be improved the performance of 9.75$\pm$1.26 (within 185$\pm$8.2 1 sec) were classified into "normal group" (n=4) and the ones, which showed R-maze performance of 7.0$\pm$2.87 within 300 sec, "deteriorated memory group" (n=5). PT was dissolved in distilled water and injected into the deteriorated memory group intraperitoneally at 30 min before R-maze for 3 consecutive days. The injected amount of PT on the 1st day was 10mg/rat, 1mg/rat both on the 2nd the 3rd day. As results, the performance was restored to 9.4$\pm$2.0 after stopping ginseng administration, although the lower performance values (1.4$\pm$0.89, 2.8$\pm$0.83, 3.8$\pm$0.84, respectively) were exerted during the three days of PT administration than before PT administration (7.0$\pm$2.87) since 1 day after administratitan of PT. The restored performance values were continuously maintained up to the level of the "normal group". However, any lower performance values were not observed when PT was administered via intraperitoneal route to the normal group in about of 2 mg/rat except 10mg1ra1. The number of errors when the foods in arms were put at only 6 places was clearly reduced during the 9 days of consecutive administration of PT as compared with untreated control. These results indicated that PT administration may enhance their cognitive function after a long lapse of time not only in the memory deteriorated rats but also in normal ones. The reason exerted lower performance values during PT administration in this paper was discussed as compared with the results of T-maze behavior of another 3-month-aged rats. of another 3-month-aged rats.

• 대한조선학회논문집
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• 제29권3호
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• pp.53-58
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• 1992

파랑중(波浪中)에서 조종운동(操縱運動)을 하는 선박(船舶)에 있어, 실용적으로 선형(線形) 계산(計算)의 경우 파랑력(波浪力)을 단순한 정상(定常) 변동(變動) 외력(外力)으로 취급하는 수가 많다. 본 논문은 이와같은 경우에 있어서 파랑력에 의한 조종(操縱) 운동(運動)에 있어서의 Memory Effect를 조사하여, 이러한 실용 계산법(計算法)의 타당성(妥當性)을 논하였다. 그 결과를 요약하면 (1) $\omega_e$의 주파수(周波數)로 선체에 작용하는 정상(定常) 파랑력에 의한 Memory Effect도 거의 무시(無視)할 수 있다. (2) 따라서, 파랑중(波浪中)에서 조종 운동을 취급하는 경우, 간이 계산법으로서, 정수(靜水)중에서의 조타(操舵) 응답과 규칙파(規則波)중에서의 선체응답(船體應答)을 계산하여 이 둘을 합(合)하여도 무방하다. 그러나, 이상의 결론(結論)은 선형 운동에 국한(局限)된 것으로서, 실제의 조종 운동은 비선형성(非線形性)이 중요시(重要視)되므로 정상(定常) 파랑(波浪) 외력(外力)에 의한 Memory Effect를 좀더 엄밀(嚴密)하게 고찰(考察)하기 위해서는 비선형(非線形) Impulse Response Function을 구(求)하고 이를 이용하여 파랑력(波浪力)에 의한 Memory Effect를 평가(評價)하여야 할 것이다.

• Journal of Korean Neurosurgical Society
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• 제44권5호
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• pp.295-302
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• 2008

Objective: Premorbid demographic backgrounds of injured individuals are likely to reflect more accurately the status of patients with traumatic brian injury (TBI) than clinical factors. However, the concrete study about the relationship between the demographic factors and neurocognitive function in TBI patients has not been reported. The object of this study was to evaluate the effect of premorbid demographic factors on the recovery of neurocognitive function following TBI. Methods: From July 1998 to February 2007, 293 patients (male: 228, female: 65) with a history of head injury, who had recovered from the acute phase, were selected from our hospital to include in this study. We analyzed the effect of premorbid demographic factors including age, sex, educational level and occupation on the recovery of neurocognitive function in each TBI subgroup as defined by Glasgow Coma Scale (GCS) score. Intelligence and memory are components of neurocognitive function, and the Korean Wechsler Intelligence Scale (K-WAIS) and the Korean memory assessment scale (K-MAS) were used in this study. The results were considered significant at p<0.05. Results: The higher level of education was a good prognostic factor for intelligence regardless of GCS score and younger age group showed a better result for memory with an exception of severe TBI group. In the severe TBI group, the meaningful effect of demographic factors was not noted by the cause of influence of severe brain injury. Conclusion: The demographic factors used in this study may be helpful for predicting the precise prognosis and developing an appropriate rehabilitation program for TBI patients.

• 한국산학기술학회논문지
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• 제21권9호
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• pp.358-372
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• 2020

본 연구는 성인의 인지예비능, 주관적 기억감퇴, 우울 및 삶의 질 등과 같은 요인들이 인지기능에 미치는 직·간접 효과를 규명하고자 하였다. 연구 대상자는 만 40세 이상 80세 미만의 성인 남녀 253명을 대상으로 설문 조사하였고, 본 연구에 사용된 도구는 인지기능 척도, 우울 척도, 삶의 질, 주관적 기억감퇴, 인지예비능 척도를 사용하였다. 데이터 결과는 SPSS 25.0를 이용하여 분석하였고, PROCESS macro for SPSS Version 3.3과 부트스트래핑 방법을 활용하였다. 연구결과, 성인의 인지예비능은 우울과 삶의 질에 영향을 미치는 것으로 나타났으며, 인지예비능과 인지기능의 다중 매개 결과는 우울 및 주관적 기억감퇴에서 매개효과가 나타나지 않았다. 그러나 삶의 질은 성인의 인지예비능과 주관적 인지기능 간의 관계에서 완전매개효과를 나타냈다. 본 연구결과를 토대로 성인들은 다양한 활동과 지속적인 훈련을 통해 인지예비능을 꾸준히 축적하여 인지기능이 긍정적인 방향으로 이어지도록 하는 것이 필요하다. 또한 건강한 성인들을 대상으로 한 인지예비능과 인지기능을 위한 많은 연구들이 실행되기를 제언한다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.447-450
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• 2004

This study was conducted to characterize groundwater and river-water fluctuations at a riverbank filtration site in Daesan-myeon adjacent to the Nakdong River, using time series analysis. Water levels from six observation wells from January 2003 to October 2003 were measured. The autocorrelation analysis indicates that the wells are divided into three groups: group 1 represents strong linearity and memory, group 2 intermediate linearity and memory, and group 3 weak linearity and memory. The analysis indicates that groundwater levels in different monitoring wells vary in response to river-water levels, groundwater withdrawal and seasonal rainfall. Cross-correlation was also divided into three groups. Group 1 shows the highest cross-correlation function (0.49 - 0.54) for a lag time of 0 hours, group 2 intermediate cross-correlation function (0.34 - 0.45), and group 3 the lowest cross-correlation function (0.23 - 0.25). Different cross-correlation functions among the 3 groups are interpreted as an effect of tile distance from the river to the pumping wells.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.86-89
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• 1995

In this pacer, The effect of the impedances in SNOSEFT s memory devices has been developed. The effect of source and drain impedances are measuring using the method of the field effect bias resistance in the inner resistance regions of the device structure and external bias resistance. The effect of impedance by source and drain resistance shows according to increasing to the storage of memory charges, shows according to a function of decreasing to the gate voltages, shows the delay of threshold voltages, The delay time of low conductance state and high conductance state by the impedance effect shows 3 [${\mu}$sec] and 1[${\mu}$sec] respectively.