• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.1
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• pp.33-45
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• 2015

To engineer tissue-like structures, cells are required to organize themselves into three-dimensional networks that mimic the native tissue micro-architecture. Here, we present agarose-based multi-well platform incorporated with electrical stimulation to build skeletal muscle-like tissues in a facile and highly reproducible fashion. Electrical stimulation of C2C12 cells encapsulated in collagen/matrigel hydrogels facilitated the formation 3D muscle tissues. Consequently, we confirmed the transcriptional upregulations of myogenic related genes in the electrical stimulation group compared to non-stimulated control group in our multi-well 3D culture platform. Given the robust fabrication, engineered muscle tissues in multi-well platform may find their use in high-throughput biological studies drug screenings.

• Korean Journal of Biological Psychiatry
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• v.25 no.4
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• pp.89-100
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• 2018

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation method that delivers 1-2 mA of current to the scalp. Several clinical studies have been conducted to confirm the therapeutic effect of major depressive disorder (MDD) patients with tDCS. Some studies have shown tDCS's antidepressant effect, while the others showed conflicting results in antidepressant effects. Our aim of this review is to understand the biological bases of tDCS's antidepressant effect and review the results of studies on tDCS's antidepressant effect. For the review and search process of MDD treatment using tDCS, the US National Library of Medicine search engine PubMed was used. In this review, we discuss the biological mechanism of tDCS's antidepressant effect and the existing published literature including meta-analysis, systematic review, control trial, open studies, and case reports of antidepressant effects and cognitive function improvement in patients with MDD are reviewed. We also discuss the appropriate tDCS protocol for MDD patients, factors predictive of response to tDCS treatment, the disadvantages of tDCS in MDD treatment, and side effects.

• Korean Journal of Biological Psychiatry
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• v.23 no.3
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• pp.89-101
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• 2016

Transcranial magnetic stimulation (TMS) is a safe, noninvasive and useful technique for exploring brain function. Especially, for the study of cognition, the technique can modulate a cognitive performance if the targeted area is engaged, because TMS has an effect on cortical network. The effect of TMS can vary depending on the frequency, intensity, and timing of stimulation. In this paper, we review the studies with TMS targeting various regions for evaluation of cognitive function. Cognitive functions, such as attention, working memory, semantic decision, discrimination and social cognition can be improved or deteriorated according to TMS stimulation protocols. Furthermore, potential therapeutic applications of TMS, including therapy in a variety of illness and research into cortical localization, are discussed.

• Korean Journal of Biological Psychiatry
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• v.24 no.4
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• pp.167-174
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• 2017

Based on advances in biotechnology and neuroscience, neuromodulation is poised to gain clinical importance as a treatment modality for psychiatric disorders. In addition to old-established electroconvulsive therapy (ECT), clinicians are expected to understand newer forms of neurostimulation, such as deep brain stimulation (DBS), vagus nerve stimulation (VNS), repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS). Given the growing interest in non-invasive neuromodulation technologies, clinicians may seek sufficient information about neuromodulation to inform their clinical practice. A growing literature suggests that applications of non-invasive neuromodulation have evidence particularly for indications where treatments are currently insufficient, such as drug-resistant depression. However, positive neuromodulation studies require replication, and the precise interactions among stimulation, antidepressant medication, and psychotherapy are unknown. Further studies of long-term safety and the impact on the developing brain are needed. Non-invasive neuromodulatory devices could enable more individualized treatment. However, do-it-yourself (DIY) stimulation kits require a better understanding of the effects of more frequent patterns of stimulation and raise concerns about clinical supervision, regulation, and reimbursement. Wide spread enthusiasm for therapeutic potential of neuromodulation in clinical practice settings should be mitigated by the fact that there are still research gaps and challenges associated with non-invasive neuromodulatory devices.

• Korean Journal of Biological Psychiatry
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• v.24 no.4
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• pp.175-187
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• 2017

Transcranial direct current stimulation (TDCS) is a clinically safe and effective method of delivering weak electric current to modulate cortical activities. And based on the cumulating scientific evidences, the method is recommended to treat major depressive disorder (MDD) and other psychiatric disorders. In this paper, we review the development of TDCS in the rising field of neuromodulation. Then with suggested biochemical and physical mechanism of TDCS, we summarize the reported cases of using TDCS to alleviate major neuropsychiatric disorders. And, in particular, the treatment of MDD is highlighted as an illustrative example of using TDCS. We discuss here the therapeutic potentials of this method in psychiatry. And in closing remarks, we evaluate the current technical limitations and suggest the future directions of this method in both the clinical and research aspects.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.189-192
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• 1995

In Visually Evoked Potentials(VEP) or Auditory Evoked Potentials(AEP), the components by the stimulation and the components which are irrelevant to the stimulation(noise or nonstationary spontaneous EEG) are mixed together. So one should average hundreds of EP waves to extract the components by the stimulation only. In this study, we have classified EP's, which are the responses of the different stimulations and different states of subjects. To classify the EP waves, the cross-correlation coefficients and neural network method(error back propagation) are used and compared.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.205-208
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• 1995

Analysis of Heart Rate Variability has been studied to estimate autonomic nervous system. PR interval represents conduction time from atrium to ventricle. PR interval variability(PRV) is also can be used to estimate autonomic nervous system. We have acquired two-state ECGs of children who are before vagal stimulation and after vagal stimulation. We applied chaotic theory to each ECG in order to analyze PRV, and compared the results from frequency domain analysis. The correlation dimension of PRV of pre-stimulated children is higher than that of post-stimulated children.

• Journal of Biomedical Engineering Research
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• v.23 no.4
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• pp.287-293
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• 2002

For non-contact nerve stimulations using time varying magnetic field, high amplitude current pulses have to be applied to a magnetic nerve stimulation coil. To increase the magnetic stimulation frequency we have to increase both power supply capacity and cooling capacity of the magnetic nerve stimulator. To alleviate these problems. we propose a new magnetic nerve stimulation coil design methods. Utilizing magnetic mirror effect of a ferro-magnetic plate attached to a magnetic stimulation coil. we have improved efficiency of the stimulation coil. We have analyzed magnetic mirror effect for various kinds of stimulation coils using the finite element method, and we present experimental results obtained with several kinds of stimulation coils.

• Journal of Biomedical Engineering Research
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• v.15 no.1
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• pp.77-82
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• 1994

We investigated the characteristic of the sensory motor coordination by measuring the hand point ins and the gaze movement to the visual and sound stimulation. Our results showed that the gaze vol ocity to sound stimulation did not depend on stimulation direction, but lagged behind 0.2 sec toward the pheriperal direction to the visual stimulation. Our data showed that to both visual and sound stimulation, the error of hand pointing value increased with an increasement of eccentricity.

• Journal of Microbiology
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• v.39 no.4
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• pp.314-320
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• 2001

Macrophages stimulated by lipopolysaccharide(LPS) from gram negative bacteria undergo activation of a group of immediate early genes including Rantes. The mouse Rantes gene promoter region contains an LPS rsponsive element(LPE) We detected 3 specific bands termed B1, B2 and 3 formed by the interaction of the LPE and proteins found in LPS-stimulated RAW 367.7 cells. An additional band B4 was determined to be an Ap-1 binding protein. The B1 band appears within 1 hour of LPS nuclear extracts from LPS-stimulation, and this protein kinase enhances B1 and formation. The B1 band can be converted to band B2/B3 by adding specific heparin column fraction purified Ser/Thr specific protein phosphatases PP-1 and PP-2A can stimulate the same conversion to about the same extent. Thus, the formation of the LRE sequence binding complex appears to be regulated by Ser/Thr protein kinase and one or more Ser/Thr specific phosphatases. At least four proteins are involved in the trgulation of the LRE-dependent Rants experssion: two binding factors that bind directly to the target sequences. and two factors that control their binding. The future purification and characterization of these binding pro-teins will reveal in detail the mechanism of Rantes gene activation after LPS stimulation.