• Molecules and Cells
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• 제37권11호
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• pp.767-776
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• 2014

Alzheimer's disease (AD) is clinically characterized with progressive memory loss and cognitive decline. Synaptic dysfunction is an early pathological feature that occurs prior to neurodegeneration and memory dysfunction. Mounting evidence suggests that aggregation of amyloid-${\alpha}$ ($A{\alpha}$) and hyperphosphorylated tau leads to synaptic deficits and neurodegeneration, thereby to memory loss. Among the established genetic risk factors for AD, the ${\varepsilon}4$ allele of apolipoprotein E (APOE) is the strongest genetic risk factor. We and others previously demonstrated that apoE regulates $A{\alpha}$ aggregation and clearance in an isoform-dependent manner. While the effect of apoE on $A{\alpha}$ may explain how apoE isoforms differentially affect AD pathogenesis, there are also other underexplored pathogenic mechanisms. They include differential effects of apoE on cerebral energy metabolism, neuroinflammation, neurovascular function, neurogenesis, and synaptic plasticity. ApoE is a major carrier of cholesterols that are required for neuronal activity and injury repair in the brain. Although there are a few conflicting findings and the underlying mechanism is still unclear, several lines of studies demonstrated that apoE4 leads to synaptic deficits and impairment in long-term potentiation, memory and cognition. In this review, we summarize current understanding of apoE function in the brain, with a particular emphasis on its role in synaptic plasticity and the underlying cellular and molecular mechanisms, involving low-density lipoprotein receptor-related protein 1 (LRP1), syndecan, and LRP8/ApoER2.

• Biomolecules & Therapeutics
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• 제25권3호
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• pp.249-258
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• 2017

To examine the effect of biflorin, a component of Syzygium aromaticum, on memory deficit, we introduced a scopolamine-induced cognitive deficit mouse model. A single administration of biflorin increased latency time in the passive avoidance task, ameliorated alternation behavior in the Y-maze, and increased exploration time in the Morris water maze task, indicating the improvement of cognitive behaviors against cholinergic dysfunction. The biflorin-induced reverse of latency in the scopolamine-treated group was attenuated by MK-801, an NMDA receptor antagonist. Biflorin also enhanced cognitive function in a naïve mouse model. To understand the mechanism of biflorin for memory amelioration, we performed Western blot. Biflorin increased the activation of protein kinase C-${\zeta}$ and its downstream signaling molecules in the hippocampus. These results suggest that biflorin ameliorates drug-induced memory impairment by modulation of protein kinase C-${\zeta}$ signaling in mice, implying that biflorin could function as a possible therapeutic agent for the treatment of cognitive problems.

• 동의생리병리학회지
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• 제36권1호
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• pp.11-17
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• 2022

In this study, we investigated the effects of Ginseng Radix (G), Rehmanniae Radix (R), and Fermented red-ginseng extracts (FRG) on cognitive function in scopolamine-induced memory-impaired mice. We measured the effects of G, R, and FRG on the improvement of memory and cognition via behavior analysis. In addition, we measured the acetylcholinesterase (AChE) activity in the hippocampus of each group of mice. The expression of β-amyloid, Tau, and BDNF in the brain tissues were observed through immunohistochemical staining. Ginseng Radix (G) and Fermented red-ginseng (FRG) have effectively improved cognitive function in the water maze test. Ginseng Radix (G), Rehmanniae Radix (R), and Fermented red-ginseng (FRG) have improved the willingness of mice to explore the new environment, as confirmed by Y maze test. In addition, immunohistochemical staining revealed that Ginseng Radix (G) decreased the expression of β-amyloid and Tau in the hippocampus. In addition, fermented red-ginseng (FRG) increased the expression of BDNF. Ginseng Radix (G), Rehmanniae Radix (R), and Fermented red-ginseng (FRG) have decreased the concentration of acetylcholinesterase in the hippocampus as compared with the control group of mice. In conclusion, Ginseng Radix (G), Rehmanniae Radix (R), and Fermented red-ginseng (FRG) are considered to have the potential for development as candidate drugs to control the progression of Alzheimer's disease (AD).

• 사물인터넷융복합논문지
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• 제8권5호
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• pp.77-83
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• 2022

낸드 플래시 메모리는 구조적으로 쓰기 전 지우기(Erase-Before-Write) 동작이 요구된다. 이것을 해결하기 위해서는 데이터 업데이트 동작이 빈번히 발생하는 페이지(Hot data page)를 구분하여 별도에 블록에 저장함으로 해결할 수 있으며 이러한 Hot data를 분류하는 기법을 핫 데이터 판단기법이라 한다. MHF(Multi Hash Function Framework)기법은 데이터 갱신요청의 빈도를 시스템 메모리에 기록하고 그 기록된 값이 일정 기준 이상일 때 해당 데이터 갱신요청을 Hot data로 판단한다. 하지만 데이터 갱신요청에 빈도만을 단순히 카운트하는 방법으로는 정확한 Hot data로 판단에 한계가 있다. 또한 데이터 갱신요청의 지속성을 판단 기준으로 하는 기법의 경우 갱신요청 사실을 시간 간격을 기준으로 순차적으로 기록한 뒤 Hot data로 판단하는 방법이다. 이러한 지속성을 기준으로 하는 방법의 경우 그 구현과 운용이 복잡한 단점이 있으며 갱신요청에 빈도를 고려하지 않는 경우 부정확하게 판단되는 문제가 있다. 본 논문은 데이터 갱신요청에 빈도와 지속성을 함께 고려한 경량화된 핫 데이터 판단기법을 제안한다.

• 한국보건간호학회지
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• 제32권1호
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• pp.81-95
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• 2018

Purpose: This study was conducted to identify the effects of a group cognitive improvement program on cognitive function, depression and self-esteem in elderly individuals with mild cognitive impairment. Methods: This was an experimental study that employed a pre-post design of a non-equivalence control group. The subjects were 52 elderly people with mild cognitive impairment, 25 of whom were assigned to the experimental group and 27 to the control group. The program was conducted for a total of 12 sessions for 60 minutes each. Data were analyzed using the ${\chi}2-test$, Fisher's exact test, and Independent t-test with the SPSS 20.0 program. Results: After the intervention, the group who participated showed improvement in all areas of cognitive function based on MMSE-KC (F=26.37, p.<0.001), the Rey Complex Figure Test: copy (F=20.66, p.<0.001), Immediate memory of Seoul Verbal Learning Test-Elderly's version (F=29.68, p.<0.001), delayed memory (F=45.79 p.<0.001), memory recall (F=28.97, p.<0.001), Forward of Digit Span Test (F=9.25, p=.004), backward (F=8.33, p.=0.006), language comprehension (F=13.42, p.<0.001), and digit symbol coding (F=17.74, p.<0.001) relative to the control group. Moreover depression (F=24.09, p.<0.001) was decreased in program participants, whereas self-esteem (F=40.24, p.<0.001) was increased. Conclusion: The program could be a useful intervention because the results show that the group cognitive improvement program has a significant effect on cognitive function, depression and self-esteem in elderly with mild cognitive impairment.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.254-254
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• 2011

The memories with nano-particles are very attractive because they are promising candidates for low operating voltage, long retention time and fast program/erase speed. In recent, various nano-floating gate memories with metal-oxide nanocrystals embedded in organic and inorganic layers have been reported. Because of the carrier generation in semiconductor, induced photon pulse enhanced the program/erase speed of memory device. We studied photo-induced electrical properties of these metal-oxide nanocrystal memory devices. At first, 2~10-nm-thick Sn and In metals were deposited by using thermal evaporation onto Si wafer including a channel with $n^+$ poly-Si source/drain in which the length and width are 10 ${\mu}m$ each. Then, a poly-amic-acid (PAA) was spin coated on the deposited Sn film. The PAA precursor used in this study was prepared by dissolving biphenyl-tetracarboxylic dianhydride-phenylene diamine (BPDA-PDA) commercial polyamic acid in N-methyl-2-pyrrolidon (NMP). Then the samples were cured at 400$^{\circ}C$ for 1 hour in N atmosphere after drying at 135$^{\circ}C$ for 30 min through rapid thermal annealing. The deposition of aluminum layer with thickness of 200 nm was followed by using a thermal evaporator, and then the gate electrode was defined by photolithography and etching. The electrical properties were measured at room temperature using an HP4156a precision semiconductor parameter analyzer and an Agilent 81101A pulse generator. Also, the optical pulse for the study on photo-induced electrical properties was applied by Xeon lamp light source and a monochromator system.

• 정보처리학회논문지D
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• 제16D권6호
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• pp.835-844
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• 2009

일반적으로 데이터베이스 시스템에서의 질의 수행은 대부분의 경우 빠른 응답시간과 더 적은 메모리 사용량을 장점으로 가지는 파이프라이닝 기법으로 이루어진다. 이 때, 질의 수행 계획(QEP)의 각각의 연산 노드들은 Open(), Next(), Close() 함수들을 지원하는 iterator의 인터페이스를 가진다. 그런데, 플래시 메모리 기반의 휴대용 기기들을 위한 임베디드 데이터베이스 시스템에서는 iterator의 Next() 함수뿐만 아니라, 현재 레코드의 이전 레코드를 리턴해주는 Previous()와 같은 함수를 필요로 하는 경우가 많다. 이는 임베디드 환경의 경우 각각의 프로그램이 사용할 수 있는 메모리의 양이 제한적이므로, 사용자가 이전 레코드를 요청하는 경우, 결과 레코드 커서가 현재 레코드를 기준으로 이전 레코드를 다시 가져와야 하기 때문이다. 본 논문에서는 이러한 임베디드 데이터베이스 시스템의 질의 수행 시 각각의 연산 노드들이 Next() 함수뿐만 아니라 Previous() 함수를 블록 단위로 지원할 수 있도록 새롭게 설계 구현하는 과정에서 발생하는 방향 전환 문제를 소개하고 이를 해결하기 위한 블록 단위 스키핑 기법을 제안한다.

• Journal of Korean Biological Nursing Science
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• 제19권4호
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• pp.276-283
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• 2017

Purpose: The aim of this study was to identify the effects of environmental factors on depressive-like behavior and memory function during adolescence. We performed behavior tests in adolescent rats exposed to environmental enrichment, handling, and social deprivation for eight weeks. Methods: Wistar rats were randomly assigned to control, environmental enrichment, handling, and social deprivation groups at the age of four weeks. Results: In the forced swim test, the immobility time in the environmental enrichment group was decreased than that in the control group (p=.038), while the immobility time in the social deprivation group was increased than that in the control group (p=.035), the environmental enrichment group (p<.001), and the handling group (p=.001). In the Morris water maze test, the social deprivation group had an increased latency time than the control group (p=.013) and the environmental enrichment group (p=.001). In the passive avoidance test, the environmental enrichment group had an increased latency time than the control group (p=.005). However, the social deprivation group had reduced latency time than the socially housed groups (control: p=.030; environmental enrichment: p<.001; handling: p<.001). Conclusion: These findings suggest that environmental factors play an important role in emotion and memory function during adolescence.

• Nutrition Research and Practice
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• 제3권1호
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• pp.43-48
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• 2009

We investigated the nutritional state of B vitamins and the neuropsychological functions in 25 subjects, aged $63.1{\pm}6.3$ years, residing in rural areas of Korea. Nutritional states of thiamin, riboflavin, and pyridoxine were assessed enzymatically in the erythrocytes, and folate concentrations were measured microbiologically in the plasma and erythrocytes. A battery of composite neuropsychological test was administered to the subjects. Plasma folate was correlated with the total intelligence score (p=0.049). Folate levels in the erythrocytes were correlated with the performance intelligence scores such as block design (p=0.017) and picture arrangement (p=0.016). The red cell folate was correlated with memory scores such as general memory (p=0.009) and delayed recall (p=0.000). Although it did not reach statistical significance, verbal memory (p=0.053) was highly correlated with the red cell folate. The red cell folate was also correlated positively with the percent of conceptual level response number score (p=0.029), and negatively with the grooved pegboard test score for the non-dominant hand (p=0.010). Fine motor coordination was also influenced by folate nutrition, as finger tapping scores in both hands were significantly correlated with red cell folate (dominant hand; p=0.026, non-dominant hand; p=0.004). Other B vitamins such as thiamin, riboflavin, and vitamin $B_6$ were not as strongly correlated with neuropsychological function test scores as folate was. These results suggest that folate nutrition influences neuropsychological function test scores significantly in humans. Further studies are needed to explore the relationship between folate or other vitamin B nutrition and neuropsychological functions and the implications thereof.

• 한국노년학
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• 제36권3호
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• pp.751-763
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• 2016

본 연구에서는 인지노화와 그에 영향을 미치는 사회심리학적 요인에 대해 개관하였다. 노화로 인한 인지기능의 변화는 세부 기능별로 상이함에도 인지노화는 쇠퇴의 관점으로 주로 해석되고 있다. 인지노화에 대한 부정적인 시각은 노화 고정관념(age stereotype)과 같은 사회심리학적 요인이 반영된 결과로 볼 수 있다. 노화 고정관념은 문화권에 따른 차이는 있으나 보통 부정적인 측면이 강하게 나타나는데, 더 부정적인 고정관념을 보일수록 기억 수행이 저하되는 것으로 나타났다. 노화 고정관념을 실험적으로 활성화시키는 경우, 긍정적인 고정관념을 제시받은 노인이 부정적인 고정관념을 제시받은 노인에 비해 더 높은 기억 수행을 보였다. 자신의 인지기능에 대한 평가인 자기신념(self-referent belief)도 인지기능에 영향을 미치는 것으로 나타난다. 보통 노인의 자기신념이 청년의 자기신념보다 낮게 나타나고, 자기기억신념의 수준은 실제 기억 수행과 관련되는 것으로 나타난다. 이상의 사회심리학적 요인이 인지기능에 미치는 영향에 대한 이론적 설명과 시사점이 논의되었다.