• YAKHAK HOEJI
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• v.39 no.3
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• pp.231-242
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• 1995

Electroconvulsive shock (ECS) increases the activity of acetylchohnesterase and decreases in brain acetylcholine levels. A large amount of free fatty acids accumulated in the brain tissue affects cerebral blood flow, brain edema and inflammation and results in brain injury. The present study examined the effect of docosahexaenoic acid (DHA) and D,L-pyroglutamic acid (D,L-PCA) on the learning and memory deficit using the passive avoidance failure technique and on the change of acetylcholine and choline level in the cerebral cortex of ECS-induced mice. The application of ECS (25mA, 0.5sec) induced a significant decrease in memory function for 30 min. ECS-induced a significant decrease in cortical acetylcholine and choline levels 1 min following the ECS application, which were almost recovered to ECS control level after 30 min. DHA (20 mg/kg, i.p.). administered 24 hr before shock. prevented the ECS-induced passive avoidance failure and the decrease of acetylcholine level 1 min following the ECS application. DHA failed to elicit a change in cortical choline level. DHA did not affect memory function and the cortical Ach and choline level of normal mice. The administration of D,L-PCA (500 mg/kg, i.p.) increased the effect of DHA on memory function and the change of cortical acetylcholine level of ECS induced mice. These results suggest that DHA treatment may be contributed to the prevention against memory deficit, and to the activation of cholinergic system in the ECS induced mice.

• Korean Journal of Biological Psychiatry
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• v.8 no.1
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• pp.131-139
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• 2001

This study was conducted to evaluate the effect of PTSD on memory function and hippocampal volume, and to identify major variables correlated to hippocampal volume and memory function. Thirty four Vietnam veterans were collected for this study, among whom eighteen were PTSD patients and sixteen were combat control subjects. The author used Impact of Event Scale(IES), Combat Exposure Scale(CES), Hamilton Depression Rating Scale(HDRS) and Beck Depression Inventory (BDI). Korea Memory Assessment Scale(K-MAS) was assessed for memory function. Magnetic resonance imaging(MRI) was used to measure hippocampal volume. There were significant differences between PTSD and Non-PTSD veterans in IES, HDRS and BDI. Significant difference was found in verbal memory and total memory of K-MAS between PTSD and Non-PTSD veterans. There was significant difference in hippocampal volume between PTSD and Non-PTSD veterans. Short term memory, verbal memory and total memory were positively correlated to hippocampal volume. Hippocampal volume was negatively correlated to IES, HDRS, and BDI. These results suggest that PTSD severity be associated with hippocampal atrophy and memory dysfunction. Reduced or smaller hippocampal volume may be preexisting risk factor for stress exposure or the development of PTSD on combat exposure.

• The Journal of Korean Medicine
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• v.38 no.2
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• pp.31-40
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• 2017

Objectives: We investigated the effect of acupuncture on memory function in relation with neurogenesis in old rats. Methods: In this study, a step-down avoidance task for short-term memory and Y-maze task for spatial memory capability were conducted. Western blot analysis for brain-derived neurotorphic factor (BDNF) and tyrosine kinase B (TrkB), and immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU) were performed. Results: Short-term memory and spatial memories were decreased in the old-aged rats. Expressions of BDNF and TrkB in the hippocampus were significantly decreased in the old-aged rats. Neurogenesis in the hippocampal dentate gyrus was also decreased in the old-aged rats. However, acupuncture treatment alleviated impairment of short-term and spatial memories induced by ageing. Acupuncture also increased the expressions of BDNF and TrkB and enhanced neurogenesis in the hippocampus. The present study showed that acupuncture alleviated ageing-induced short-term and spatial memory loss by increasing of BDNF and neurogenesis. Acupuncture at ST41-acupoint showed most potent effect than at ST36-acupoint or non-acupoint. Conclusions: Acupuncture might be used as the effective therapeutic modality to ameliorate the age-related decrease of brain functions.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.298.1-298.1
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• 2016

Two-dimensional materials have been received significant interest after the discovery of graphene due to their fascinating electronic and optical properties for the application of novel devices. However, graphene lack of certain bandgap which is essential requirement to achieve high performance field-effect transistors. Analogous to graphene materials, molybdenum disulfide ($MoS_2$) as one of transition-metal dichalcogenides family presents considerable bandgap and exhibits promising physical, chemical, optical and mechanical properties. Here we studied nonvolatile memory based on $MoS_2$ which is grown by chemical vapor deposition (CVD) method. $MoS_2$ growth was taken on $1.5{\times}1.5cm^2$ $SiO_2$/Si-substrate. The samples were analyzed by Raman spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy. Current-voltage (I-V) characteristic was carried out HP4156A. The CVD-$MoS_2$ was analyzed as few layers and 2H-$MoS_2$ structure. From I-V measurement for two metal contacts on CVD-$MoS_2$ sample, we found typical resistive switching memory effect. The device structures and the origin of nonvolatile memory effect will be discussed.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.299-308
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• 2018

This study was conducted to examine the mediating effect of executive function deficiencies on the relationship between smartphone addiction and memory impairment and to suggest treatment implications for adults with smartphone addiction symptoms. For this study, 300 adults(146 males and 154 females) were conducted smartphone addiction scale, Barkley Deficits in Executive Functioning Scale-Short Form(BDEFS-SF), and Multifactorial Memory Questionnaire(MMQ). The results are as follows. First, correlation analyses showed that smartphone addiction, executive function deficiencies, and memory impairment were positively correlated. Second, Smartphone addiction group showed significantly higher scores on all of the subfactors of executive function and memory impairment. Third, Stepwise regression analyses revealed that self-organization/problem solving, self-management to time, self-restraint, and withdrawal were the best predictors of memory impairment. Forth, Executive function deficiencies fully mediated the relationship between smartphone addiction and memory impairment. These findings were considered to suggest that treatment programs for smartphone addiction group needed to include training for cognitive improvement such as executive function rehabilitation.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.240.2-240.2
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• 2013

The device scale of flash memory was confronted with quantum mechanical limitation. The next generation memory device will be required a break-through for the device scaling problem. Especially, graphene is one of important materials to overcome scaling and operation problem for the memory device, because ofthe high carrier mobility, the mechanicalflexibility, the one atomic layer thick and versatile chemistry. We demonstrate the hybrid memory consisted with the metal-oxide quantum dots and the mono-layered graphene which was transferred to $SiO_2$ (5 nm)/Si substrate. The 5-nm thick secondary $SiO_2$ layer was deposited on the mono-layered graphene by using ultra-high vacuum sputtering system which base pressure is about $1{\times}10^{-10}$ Torr. The $In_2O_3$ quantum dots were distributed on the secondary $SiO_2$2 layer after chemical reaction between deposited In layer and polyamic acid layer through soft baking at $125^{\circ}C$ for 30 min and curing process at $400^{\circ}C$ for 1 hr by using the furnace in $N_2$ ambient. The memory devices with the $In_2O_3$ quantum dots on graphene monolayer between $SiO_2$ thin films have demonstrated and evaluated for the application of next generation nonvolatile memory device. We will discuss the electrical properties to understating memory effect related with quantum mechanical transport between the $In_2O_3$ quantum dots and the Fermi level of graphene layer.

• The Journal of Korean Physical Therapy
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• v.19 no.4
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• pp.25-32
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• 2007

Purpose: The purpose of this study was to evaluate the effect of computerized neurocognitive function program on cognitive function about memory and attention with stroke. Methods: 24subjects with stroke were recruited. Twelve of subjects received conventional therapy including physical therapy, occupational therapy and language therapy. Another subjects received additional computer assisted cognitive training using Computer-aided Cognitive rehabilitation training system(COMCOG, MaxMedica Inc., 2004). All patients were assessed their cognitive function of memory and attention using Computerized Neurocognitive Function Test(CNT, MaxMedica Inc., 2004) before treatment and 6 weeks after treatment. Results: Before the treatment, two groups showed no difference in cognitive function(p>0.05). After 6 weeks, two groups showed significantly difference in digit span (forward, backward), verbal learning(A5, $A1{\sim}A5$), auditory CPT(n), visual CPT(n)(p<0.05). After treatment, the experimental group showed a significant improvement of digit span(forward, backward), verbal learning(A5, $A1{\sim}A5$), visual span (forward, backward), auditory CPT(n, sec), visual CPT(n, sec), and trail-making (A, B)(p<0.05). Conclusion: Computerized neurocognitive function program would be improved cognitive function of memory and attention in patients with stoke.

• Computational Structural Engineering : An International Journal
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• v.2 no.1
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• pp.43-50
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• 2002

This paper presents a method to predict dynamic responses of floating bodies in the time domain. Because of the frequency-dependence of the radiation wave forces, the memory effect must be taken into account when the responses are evaluated in the time domain. Although the formulations firstly developed by Cummins (1962) have been well-known for this purpose, the effective numerical procedure has not been established yet. This study employs FFT (Fast Fourier Transform) algorithm to evaluate the memory effect function, and the equations of motion of an integro-differential type are solved by Newmark-β method. Numerical examples for a truncated circular cylinder have indicated the effectiveness of the proposed numerical procedure.

• YAKHAK HOEJI
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• v.36 no.1
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• pp.56-65
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• 1992

The present study examined the effects of carbon monoxide (CO) intoxication and aging on learning and memory deficit in young($5{\sim}8$ weeks) and aged($52{\sim}66$ weeks) mice, using the step down and step through passive avoidance failure techniques. We also investigated the effects of ginseng saponins on memory deficit. Significant decrease in memory registration, retention and retrieval function in young mice and decrease in memory registration and retention function in aged mice were observed. Normal young mice were apt to perform to a great degree of passive avoidance response than normal aged mice, but there was no difference between both groups by CO exposure. Administration of ginseng saponins showed an improvement on passive avoidance failure induced by CO exposure.

• The Korea Journal of Herbology
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• v.22 no.4
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• pp.51-58
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• 2007

Objectives : Investigation of the memory and cognitive enhancing effect of HT008-1 in scopolamine induced amnesia mice. Methods : At 60 min before acquisition trials, HT008-1 (30, 100, 300 mg/kg p.o.) was administered, and 30 min later, mice were injected with scopolamin (1.0 mg/kg, i.p.). In the passive avoidance test, acquisition trials were carried out 30 min after a single scopolamine treatment. Retention trials were carried out 24h after acquisition trials. Y-maze test was carried out 30 min after a single scopolamine treatment. Spontaneous alternation behavior during an 8-min session was recorded. Inhibitory effects of HT008-1 (0.01, 0.1, 1.0 mg/ml) on AChE activity was measured. Result : HT008-1 ameliorated scopolamine-induced learning impairments and spatial cognitive function in passive avoidance and Y-maze test, respectively. Moreover HT008-1 showed a significant inhibitory effect on AChE activity. Discussion: This study presented that eMultiherb mixture HT008-1 enhanced learning memory and spatial cognitive function in scopolamine-induced amnesia mice. These results suggest that the effect of HT008-1 may be dependent on the inhibition of AChE activity.