• Electrical & Electronic Materials
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• v.8 no.5
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• pp.626-632
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• 1995

In this paper, The effect of the impedances in SNOSFET's memory devices has been developed. The effect of source and drain impedances measured by means of two bias resistances - field effect bias resistance by inner region, external bias resistance. The effect of the impedances by source and drain resistance shows the dependence of the function of voltages applied to the gate. It shows the differences of change in source drain voltage by means of low conductance state and high conductance state. It shows the delay of threshold voltages. The delay time of low conductance state and high conductance state by the impedances effect shows 3[.mu.sec] and 1[.mu.sec] respectively.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.10
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• pp.131-136
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• 2007

In this paper, we estimated the effects of different color stimulation on the cognitive function of human quantitatively. For the stimulations we used color lights with 6 color filters such as red, yellow, green, blue, violet and white. The experiment was performed in a soundproof chamber. 50 young male and female subjects were participated in the experiment. To find the appropriate color cognitive function, the endogenous visuospatial attention task(EVAT) and one back working memory task(OWMT) were performed. The reaction time and accuracy degree were measured. The results showed that the reaction time of EVAT was the fastest and the accuracy degree of attention task was the highest in green environment. The reaction time of OWMT was the fastest in yellow and the accuracy degree of memory task was the highest in blue. For physiological parameters, we measured electrocardiogram(ECG) and HRV spectrum analysis, HF/LF color environment. These results can be used as an indicator in the design of color environment and clinical applications.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.261-262
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• 2003

Shape memory polyurethane (PU) with soft and hard segments has been extensively researched since its discovery by Mitsubishi in 1988 [1]. Hard segments can be formed via hydrogen bonding and crystallization, function as physical crosslinks below melting point (Tm). The reversible phase transformation of the soft segment is responsible for the shape memory effect. (omitted)

• Korean Journal of Pharmacognosy
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• v.52 no.1
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• pp.55-60
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• 2021

Belamcandae Rhizoma (BR), the rhizome of Belamcanda chinensis (L.) DC., possesses various biological properties such as anti-inflammatory activity, antioxidant activity and antimutagenic activity. However, there have been no studies on the anti-amnesic effect of BR. In this study, we assessed the improvement effect of BR extract on scopolamine-induced amnesia in mice. ICR mice were administrated with BR (50, 100 or 200 mg/kg, p.o.) and were subsequently injected of scopolamine (1 mg/kg, i.p.) 30 min before behavioral tasks (Y-maze, passive avoidance and Morris water maze tasks). To further assess the possible mechanisms of BR, the ex vivo acetylcholinesterase (AChE) activity was also evaluated. BR could ameliorate scopolamine-induced memory impairment and could regulate the cholinergic function by inhibiting the AChE activity. These data demonstrated that BR exert candidate extract against amnesia by restoring the cholinergic activity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.6
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• pp.1236-1242
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• 2002

In order to make an efficient prescription and cope with dementia, learning and memory functions of Sprague-Dawley model rats were tested with Morris water maze. And to evaluate the effect of the sample drug(CHM) on choline acetyltranferase and acetylcholine esterase, immunoreactive measurement and enzymatic activity measuring were carried out. Rats were injected with ibotenic acid through hippocampus CA1 and CA3 area. The results are as following. CHM improves the learning ability in the acquisition test and memory function in the retention test significantly. And CHM increases the level of AChE which is resolving acetylcholine. Though it doesn't increase the level of ChAT significantly which is synthesizing acetylcholine, but it shows the tendency of increase. So these results show that CHM improve the cholinergic catabolism and anabolism, and the increment of metabolic activity of cholinergic system. Thus it can be concluded that CHM will be helpful to cholinergic brain disease induced by primary or senile reduction of acetylcholine secretive activity.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.1
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• pp.87-97
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• 2023

PURPOSE: The purpose of this study was to investigate the effect of multimodal intervention through VR (virtual reality)-based immersion program on the cognitive function and brain activity of patients with mild cognitive impairment. METHODS: The subjects of the study were 10 people in the experimental group who applied a complex intervention that performed cognitive tasks using the movement of the upper extremities through the VR program, and 10 people in the control group who received traditional occupational therapy. After the study intervention was applied 5 times a week, 30 minutes a day for a total of 8 weeks, LOTCA-G(Lowenstein Occupational Therapy Cognitive Assessment for Geriatric Population) and NIRSIT LITE were used to compare. RESULTS: Significant differences in cognitive function and brain activity were noted between the pre- test and post-test in the experimental group. Brain activity showed statistically significant differences in four channels of the working memory domain and one channel of the metacognitive domain (p < . 05). Comparative analysis of the difference between the two groups revealed statistically significant differences in cognitive function and brain activity. The brain activity showed statistically significant differences in three channels of the working memory domain and one channel of the metacognitive domain (p < .05). CONCLUSION: Through the results of this study, it was found that the complex intervention of performing cognitive tasks using upper extremity movements through the VR program had a positive effect on the cognitive function of patients with mild cognitive.

• Journal of Ginseng Research
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• v.37 no.1
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• pp.100-107
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• 2013

This study examined the effect of fermented ginseng (FG) on memory impairment and ${\beta}$-amyloid ($A{\beta}$) reduction in models of Alzheimer's disease (AD) in vitro and in vivo. FG extract was prepared by steaming and fermenting ginseng. In vitro assessment measured soluble $A{\beta}42$ levels in HeLa cells, which stably express the Swedish mutant form of amyloid precursor protein. After 8 h incubation with the FG extract, the level of soluble $A{\beta}42$ was reduced. For behavioral assessments, the passive avoidance test was used for the scopolamine-injected ICR mouse model, and the Morris water maze was used for a transgenic (TG) mouse model, which exhibits impaired memory function and increased $A{\beta}42$ level in the brain. FG extract was treated for 2 wk or 4 mo on ICR and TG mice, respectively. FG extract treatment resulted in a significant recovery of memory function in both animal models. Brain soluble $A{\beta}42$ levels measured from the cerebral cortex of TG mice were significantly reduced by the FG extract treatment. These findings suggest that FG extract can protect the brain from increased levels of $A{\beta}42$ protein, which results in enhanced behavioral memory function, thus, suggesting that FG extract may be an effective preventive or treatment for AD.

• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.95-102
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• 2019

This study was to investigate the effect of eye movement and intentional finger movement on cognitive ability. Normal adult subjects were randomly divided into two groups: saccadic eye movement(SEM) and intentional finger movement(IFM). After 2 weeks of intervention, Digit span was used for short-term memory test and N-back was used for working memory test. As a result, the short-term memory of the IFM group increased significantly over time, and the follow-up test showed difference between group. The IFM group's the execution time, the error count and the accuracy rate of n-back item showed significant effects over time. The SEM group's the execution time and the accuracy of n-back item showed significant effects over time. In conclusion, the IFM method, which is a multiple stimulus that can activate the cerebral cortex more extensively than the single stimulus SEM, may be more useful as an intervention method of cognitive function improvement.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.47-52
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• 2012

A power amplifier is one of important factors for basestation's efficiency and the researches for efficency enhancement focus Doherty amplifier structure with GaN power devices in these days. A memory effect of Doherty amplifier affect operation characteristics for linearity and efficiency. This paper reports on electrothermal nonlinearity modeling and compensation for GaN Doherty amplifier's distortion. Also this paper reports on the dynamic expression of the instantaneous junction temperature as a function of the instantaneous dissipated power. We design distortion model for GaN Doherty amplifier and predistortion compensator for electrothermal memory effect from the proposed behavior model parameters. The simulations was evaluated by ADS Tools and GaN Doherty amplifier with 37dBm. The GaN Doherty amplifier with compensator enhanced about 16dB than without electrothemal memory effect compensator in 2-tone output spectrum.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.52-58
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• 2022

Phosphatidylserine (PS) is an essential component of the cerebral cortex and is associated with cognitive function. In this systematic review, the effects of PS on cognitive function in the elderly population are examined. The literature search included PubMed, EMBASE, Cochrane, and Web of Science databases. Subsequently, nine studies, including five randomized controlled trials and four pre-post studies, were selected. There were 961 participants in the selected studies; PS dosage varied from 100 to 300 mg/d, and the experimental period ranged from 6 weeks to 6 months. Five out of the nine selected studies were assessed to have a 'low' risk of bias, whereas the other four studies were assessed to have 'some concerns' regarding the risk of bias. The results of the meta-analysis concluded that PS had a positive effect on the memory of older adults with cognitive decline. Thus, PS appears to improve age-associated cognitive decline, especially memory, with no adverse effects.