• Molecules and Cells
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• v.42 no.11
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• pp.739-746
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• 2019

Significant knowledge about the pathophysiology of Alzheimer's disease (AD) has been gained in the last century; however, the understanding of its causes of onset remains limited. Late-onset AD is observed in about 95% of patients, and APOE4-encoding apolipoprotein E4 (ApoE4) is strongly associated with these cases. As an apolipoprotein, the function of ApoE in brain cholesterol transport has been extensively studied and widely appreciated. Development of new technologies such as human-induced pluripotent stem cells (hiPSCs) and CRISPR-Cas9 genome editing tools have enabled us to develop human brain model systems in vitro and readily manipulate genomic information. In the context of these advances, recent studies provide strong evidence that abnormal cholesterol metabolism by ApoE4 could be linked to AD-associated pathology. In this review, we discuss novel discoveries in brain cholesterol dysregulation by ApoE4. We further elaborate cell type-specific roles in cholesterol regulation of four major brain cell types, neurons, astrocytes, microglia, and oligodendrocytes, and how its dysregulation can be linked to AD pathology.

• Journal of the Korean Society of Radiology
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• v.7 no.6
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• pp.433-439
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• 2013

In this study, human head-mimicking phantom was developed for brain disease treatment study using focused ultrasound. Acoustic parameters of skin, skull and brain were investigated through literature investigation and adequate substitutes according to each tissue were suggested. In the case of skin phantom, construction ratio of glycerol-based TMM phantom was controlled to mimic real skin. The suitability of skull substitutes was evaluated through measurement of acoustic parameters. In the case of brain phantom, transparent egg white phantom was used to observe thermal properties of focused ultrasound. Combined human-head-mimicking phantom using each substitutes was fabricated for development of brain disease treatment protocol. Denaturation of brain phantom according to ultrasonic condition was observed for validation.

• Biomolecules & Therapeutics
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• v.25 no.2
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• pp.149-157
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• 2017

The interleukin-1 receptor antagonist (IL-1RA) is a potential stroke treatment candidate. Intranasal delivery is a novel method thereby a therapeutic protein can be penetrated into the brain parenchyma by bypassing the blood-brain barrier. Thus, this study tested whether intranasal IL-1RA can provide neuroprotection and brain penetration in transient cerebral ischemia. In male Sprague-Dawley rats, focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) for 1 h. The rats simultaneously received 50 mg/kg human IL-1RA through the intranasal (IN group) or intraperitoneal route (IP group). The other rats were given 0.5 mL/kg normal saline (EC group). Neurobehavioral function, infarct size, and the concentration of the administered human IL-1RA in the brain tissue were assessed. In addition, the cellular distribution of intranasal IL-1RA in the brain and its effect on proinflammatory cytokines expression were evaluated. Intranasal IL-1RA improved neurological deficit and reduced infarct size until 7 days after MCAO (p<0.05). The concentrations of the human IL-1RA in the brain tissue 24 h after MCAO were significantly greater in the IN group than in the IP group (p<0.05). The human IL-1RA was confirmed to be co-localized with neuron and microglia. Furthermore, the IN group had lower expression of $interleukin-1{\beta}$ and tumor necrosis $factor-{\alpha}$ at 6 h after MCAO than the EC group (p<0.05). These results suggest that intranasal IL-1RA can reach the brain parenchyma more efficiently and provide superior neuroprotection in the transient focal cerebral ischemia.

• International Journal of Stem Cells
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• v.16 no.4
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• pp.415-424
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• 2023

Therapeutic efficacy of mesenchymal stem cells (MSCs) is determined by biodistribution and engraftment in vivo. Compared to intravenous infusion, biodistribution of locally transplanted MSCs are partially understood. Here, we performed a pharmacokinetics (PK) study of MSCs after local transplantation. We grafted human MSCs into the brains of immune-compromised nude mice. Then we extracted genomic DNA from brains, lungs, and livers after transplantation over a month. Using quantitative polymerase chain reaction with human Alu-specific primers, we analyzed biodistribution of the transplanted cells. To evaluate the role of residual immune response in the brain, MSCs expressing a cytosine deaminase (MSCs/CD) were used to ablate resident immune cells at the injection site. The majority of the Alu signals mostly remained at the injection site and decreased over a week, finally becoming undetectable after one month. Negligible signals were transiently detected in the lung and liver during the first week. Suppression of Iba1-positive microglia in the vicinity of the injection site using MSCs/CD prolonged the presence of the Alu signals. After local transplantation in xenograft animal models, human MSCs remain predominantly near the injection site for limited time without disseminating to other organs. Transplantation of human MSCs can locally elicit an immune response in immune compromised animals, and suppressing resident immune cells can prolong the presence of transplanted cells. Our study provides valuable insights into the in vivo fate of locally transplanted stem cells and a local delivery is effective to achieve desired dosages for neurological diseases.

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.214.2-215
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• 2001

No Abstract, See Full Text

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.2
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• pp.251-256
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• 2008

Many researchers are studying about human Brain-Computer Interface(BCI) that it based on electroencephalogram(EEG) signals of multichannel. The researches of EEG signals are used for detection of a seizure or a epilepsy and as a lie detector. The researches about an interface between Brain and Computer have been studied robots control and game of using human brain as engineering recently. Especially, a field of brain studies used EEG signals is put emphasis on EEG artifacts elimination for correct signals. In this paper, we measure EEG signals as human emotions and divide it into five frequence parts. They are calculated related the percentage of selecting range to total range. the calculating values are compared standard values by Bayesian Network. lastly, we show the human face avatar as human Emotion.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.154.1-154
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• 2001

The paper describes a new type of robot called "artificial liferobot" which is able to learn, make decisions, and behave by itself based on a brain-type computing technique called "artificial brain". The artificial liferobot has self-learning ability from the environment by the interactions between human being and it. The artificial brain makes the artificial liferobot to behave by itself with its intensions like living things as human being. We briefly introduce one attempt of our researches for developing cognitive and behavioral intelligent artificial liferobot in out laboratory. One of our purposes is the development of the artificial liferobot, which plays an Important role in taking care of elderly and infirm people in a rapidly aging society.

• Journal of the HCI Society of Korea
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• v.12 no.4
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• pp.75-80
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• 2017

With the technological development, benefits of Virtual Reality (VR) has become a key of medium in communication research. In addition, explaining human minds with physiological data has become more popular since more accurate and detailed data can be expressed. However, reading brain signals in a virtual environment setting with psychophysiological measures (e.g. EEG and fNIRS) has remained a difficulty for researchers due to a technical constraint. Since a combination of cables for brain measures attached to a head cap obstruct wearing a Head-Mounted Display (HMD) over the cap, measuring brain activities with multiple channels on several areas of the brain is inappropriate in the VR setting. Therefore, we have developed a new brain measurement cap that includes probe connectors and brackets enabling a direct connection to the HMD. We highly expect this method would contribute to cognitive psychology research measuring brain signals with new technology.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.97-106
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• 1996

The impact response of the human brain has been determined by three-dimensional finite element modeling. The model includes a layered shell closely representing the cranial bones with the interior contents occupied by an incompressible contimuum to simulate the brain. Flax and tentorium modeled with 4 node membrane element were also incorporated. The computed pressure-time histories at 4 locations within the brain element compared quite favorably with previously published experimental data from cadaver experiments. A parametric study was subsequently conducted to identify the model response when the impact were varied.

• Animal cells and systems
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• v.8
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• pp.18-18
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• 2004