• JSTS:Journal of Semiconductor Technology and Science
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• 제2권3호
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• pp.170-172
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• 2002

The epilayer of vertically stacked, self-assembled InAs Quantum Dots (QDs)was grown by MBE with solid sources in non-cracking K-cells, and the sample was fabricated to a FET structure using a conventional technology. The device characteristic and performance were studied. At 77K and room temperature, the threshold voltage shift values are 0.75V and 0.35 V, which are caused by the trapping and detrapping of electrons in the quantum dots. Discharging and charging curves form the part of a hysteresis loop to exhibit memory function. The electrical injection of confined electrons in QDs products the threshold voltage shift and memory function with the persistent electron trapping, which shows the potential use for a room temperature application.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.879-882
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• 1999

The effects of the substrate bias on the performance of programming erasing in p-channel flash memory cell have been investigated. It is found that applying positive substrate bias can improve the programming and erasing speed. This improvements can be explained by Substrate Current Induced Hot Electron Injection. From the results, we can confirm that BTB programming method is better in programming and erasing speed than CHE programming method.

• Biomolecules & Therapeutics
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• 제22권1호
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• pp.17-26
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• 2014

${\alpha}$-Asarone exhibits a number of pharmacological actions including neuroprotective, anti-oxidative, anticonvulsive, and cognitive enhancing action. The present study investigated the effects of ${\alpha}$-asarone on pro-inflammatory cytokines mRNA, microglial activation, and neuronal damage in the hippocampus and on learning and memory deficits in systemic lipopolysaccharide (LPS)-treated C57BL/6 mice. Varying doses of ${\alpha}$-asarone was orally administered (7.5, 15, or 30 mg/kg) once a day for 3 days before the LPS (3 mg/kg) injection. ${\alpha}$-Asarone significantly reduced TNF-${\alpha}$ and IL-$1{\beta}$ mRNA at 4 and 24 hours after the LPS injection at dose of 30 mg/kg. At 24 hours after the LPS injection, the loss of CA1 neurons, the increase of TUNEL-labeled cells, and the up-regulation of BACE1 expression in the hippocampus were attenuated by 30 mg/kg of ${\alpha}$-asarone treatment. ${\alpha}$-Asarone significantly reduced Iba1 protein expression in the hippocampal tissue at a dose of 30 mg/kg. ${\alpha}$-Asarone did not reduce the number of Iba1-expressing microglia on immunohistochemistry but the average cell size and percentage areas of Iba1-expressing microglia in the hippocampus were significantly decreased by 30 mg/kg of ${\alpha}$-asarone treatment. In the Morris water maze test, ${\alpha}$-asarone significantly prolonged the swimming time spent in the target and peri-target zones. ${\alpha}$-Asarone also significantly increased the number of target heading and memory score in the Morris water maze. The results suggest that inhibition of pro-inflammatory cytokines and microglial activation in the hippocampus by ${\alpha}$-asarone may be one of the mechanisms for the ${\alpha}$-asarone-mediated ameliorating effect on memory deficits.

• 대한본초학회지
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• 제28권6호
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• pp.119-127
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• 2013

Objectives : ${\beta}$-Asarone (BAS) is an active ingredient in Acori Rhizoma. This study investigated anti-neuroinflammatory and memory ameliorating effects of BAS in systemic lipopolysaccharide (LPS)-treated C57BL/6 mice. Methods : BAS was administered orally at doses of 7.5, 15, and 30 mg/kg for 3 days prior to LPS (3 mg/kg, intraperitoneal) injection. Pro-inflammatory cytokine mRNA, including tumor necrosis factor-${\alpha}$ (TNF-ㅍ), interleukin (IL)-$1{\beta}$ and IL-6, was measured in hippocampus tissue using real-time polymerase chain reaction at 4 h after the LPS injection. An ameliorating effect of 30 mg/kg BAS on learning and memory impairment in the LPS-treated mice was verified using the Morris water maze test. Results : BAS significantly attenuated up-regulation of TNF-${\alpha}$, IL-$1{\beta}$, and IL-6 mRNA in hippocampus tissue of the LPS-treated mice. In acquisition training test, BAS improved learning performance of the LPS-treated mice with a significant decrease of escape latency to the platform. In memory retention test, BAS also ameliorated memory impairment of the LPS-treated mice with a significant increase of swimming time in zones neighboring to the platform, number of target heading, and memory score. Conclusion : The results suggest that inhibition of pro-inflammatory cytokines and neuroinflammation in the hippocampus by BAS could be one of the mechanisms for BAS-mediated ameliorating effect on learning and memory impairment in LPS-treated mice.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.240-240
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• 2010

A multiple alloy metal nano-dots memory using FN tunneling was investigated in order to confirm its structural possibility for future flash memory. In this work, a multiple FePt nano-dots device with a high work function (~5.2 eV) and extremely high dot density (${\sim}\;1.2{\times}10^{13}/cm^2$) was fabricated. Its structural effect for multiple layers was evaluated and compared to one with a single layer in terms of the cell characteristics and reliability. We confirm that MOS capacitor structures with 2-4 multiple FePt nano-dot layers provide a larger threshold voltage window and better retention characteristics. Furthermore, it was also revealed that several process parameters for block oxide and inter-tunnel oxide between the nano-dot layers are very important to improve the efficiency of electron injection into multiple nano-dots. From these results, it is expected that a multiple FePt nano-dots memory using Fowler-Nordheim (FN)-tunneling could be a candidate structure for future flash memory.

• The Korean Journal of Physiology and Pharmacology
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• 제22권3호
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• pp.257-267
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• 2018

The present study aimed to evaluate the cinnamic acid effect on memory impairment, oxidative stress, and cholinergic dysfunction in streptozotocin (STZ)-induced diabetic model in mice. In this experimental study, 48 male Naval Medical Research Institute (NMRI) mice (30-35 g) were chosen and were randomly divided into six groups: control, cinnamic acid (20 mg/kg day, i.p.), diabetic, and cinnamic acid-treated diabetic (10, 20 and 40 mg/kg day, i.p.). Memory was impaired by administering an intraperitoneal STZ injection of 50 mg/kg. Cinnamic acid was injected for 40 days starting from the 21st day after confirming STZ-induced dementia to observe its therapeutic effect. Memory function was assessed using cross-arm maze, morris water maze and passive avoidance test. After the administration, biochemical parameters of oxidative stress and cholinergic function were estimated in the brain. Present data indicated that inducing STZ caused significant memory impairment, whereas administration of cinnamic acid caused significant and dose-dependent memory improvement. Assessment of brain homogenates indicated cholinergic dysfunction, increase in lipid peroxidation and reactive oxygen species (ROS) levels, and decrease in glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) activities in the diabetic group compared to the control animals, whereas cinnamic acid administration ameliorated these indices in the diabetic mice. The present study demonstrated that cinnamic acid improves memory by reducing the oxidative stress and cholinergic dysfunction in the brain of diabetic mice.

• Animal cells and systems
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• 제12권4호
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• pp.203-209
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• 2008

Berberine, an isoquinoline alkaloid found in Coptidis Rhizoma(goldenthread) extract, has multiple pharmacological effects such as anti-inflammatory, antimicrobial and anti-ischemic effects. In the present study, we examined the effects of berberine on neuronal survival and differentiation in a hippocampal precursor cell line and in the memory deficient rat model. Berberine increased in a dose dependent manner the survival of hippocampal precursor cells as well as differentiated cells. In addition, berberine promoted neuronal differentiation of hippocampal precursor cells. In the memory deficient rat model induced by stereotaxic injection of ibotenic acid into entorhinal cortex(Ibo model), hippocampal cells were increased about 2.7 fold in the pyramidal layer of CA1 region and about 2 fold in the dentate gyrus by administration of berberine after 2 weeks of ibotenic acid injection. Furthermore, neuronal cells immunoreactive to calbindin were increased in the hippocampus and entorhinal cortex area by administration of berberine. Taken together, these results suggest that berberine has neuroprotective effect in the Ibo model rat brain by promoting the neuronal survival and differentiation.

• 약학회지
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• 제52권5호
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• pp.384-393
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• 2008

We examined the effect of green tea extract (GTE) and L-theanine combination on the $A{\beta}_{1-42}$-induced memory dysfunction. GTE and combination were administrated into mice for 3 weeks followed by injection of $A{\beta}_{1-42}$ to induce memory impairment. GTE and L-theanine administration significantly improved cognitive ability and reduced $A{\beta}_{1-42}$ level accompanied with the inhibition of neuronal cell death and activities of secretase. These results suggest that GTE and L-theanine combination may be a useful for preventing for the development or progression of Alzheimer's disease.

• 생약학회지
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• 제50권4호
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• pp.253-259
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• 2019

Chaenomeles speciose Nakai (CSP) or Chaenomeles sinensis Koehne (CSS) (Rosaceae) has been used, traditionally, to treat muscle problems and gastric dampness in eastern Asia countries. Therefore, many studies have focused on investigating its active compounds and effects on muscle pain, arthritis and gastro-intestinal diseases. Recently, several studies reported that CSS extract degrade amyloid plaques and enhance synaptic acetylcholine level in vivo and in vitro. Although these two Chaenomeles species are used without differences, CSP is reported to contains more phenolic compounds which are known to enhance memory. Therefore, in this study, we investigated the memory ameliorating effects of CSP by employing the passive avoidance test, Y-maze task and novel object recognition test. CSP (30 or 100 mg/kg) ameliorated the declined memory induced by scopolamine injection and enhanced the brain-derived neurotrophic factor (BDNF) levels along with post synaptic density protein 95 (PSD 95) levels at the hippocampus of the scopolamine-injected mouse brain. These results suggested that CSP alleviates the cognition declines caused by cholinergic blockade via enhancing BDNF levels and PSD 95, and that it would enhance memory formation and be useful for treating memory declines.

• Journal of Microbiology and Biotechnology
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• 제21권8호
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• pp.874-883
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• 2011

Many studies have shown that the steamed root of Rehmannia glutinosa (SRG), which is widely used in the treatment of various neurodegenerative diseases in the context of Korean traditional medicine, is effective for improving cognitive and memory impairments. The purpose of this study was to examine whether SRG extracts improved memory defects caused by administering scopolamine (SCO) into the brains of rats. The effects of SRG on the acetylcholinergic system and proinflammatory cytokines in the hippocampus were also investigated. Male rats were administered daily doses of SRG (50, 100, and 200 mg/kg, i.p.) for 14 days, 1 h before scopolamine injection (2 mg/kg, i.p.). After inducing cognitive impairment via scopolamine administration, we conducted a passive avoidance test (PAT) and the Morris water maze (MWM) test as behavioral assessments. Changes in cholinergic system reactivity were also examined by measuring the immunoreactive neurons of choline acetyltransferase (ChAT) and the reactivity of acetylcholinesterase (AchE) in the hippocampus. Daily administration of SRG improved memory impairment according to the PAT, and reduced the escape latency for finding the platform in the MWM. The administration of SRG consistently significantly alleviated memory-associated decreases in cholinergic immunoreactivity and decreased interleukin-$1{\beta}$ (IL-$1{\beta}$) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) mRNA expression in the hippocampus. The results demonstrated that SRG had a significant neuroprotective effect against the neuronal impairment and memory dysfunction caused by scopolamine in rats. These results suggest that SRG may be useful for improving cognitive functioning by stimulating cholinergic enzyme activities and alleviating inflammatory responses.