• Journal of Industrial Technology
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• v.43 no.1
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• pp.25-31
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• 2023

Stretchable and flexible electronics that comply with dynamic movements and micromotion of the human tissues can enable real-time monitoring of physiologic signals onto the human skin and in the brain, respectively. Especially, gallium based liquid metal stretchable electronics can offer human-interactive biosensors to monitor various physiologic parameters. However, the liquid-like nature, surface oxidation and contamination by organic materials, and low biostability of the liquid metals have still limited the long-term use as bioelectronics. Here we introduced electrochemical deposition without oxidation pathways to overcome these practical challenges in liquid metal bioelectronics. CNT/PDDA composite with reduction way and PEDOT:BF₄ with oxidation way under organic solvent are suggested as rationally designed material engineering approaches. We confirmed that the structures with the soft, flexible, and stretchable liquid metal platform can successfully detect dopamine with a high sensitivity and selectivity, record neural signals including action potentials without scar formation, and monitor physiologic signals such as EMG and ECG.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.1
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• pp.105-125
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• 2024

Gliomas are the most common malignant brain tumor and cause the most deaths. Manual brain tumor segmentation is expensive, time-consuming, error-prone, and dependent on the radiologist's expertise and experience. Manual brain tumor segmentation outcomes by different radiologists for the same patient may differ. Thus, more robust, and dependable methods are needed. Medical imaging researchers produced numerous semi-automatic and fully automatic brain tumor segmentation algorithms using ML pipelines and accurate (handcrafted feature-based, etc.) or data-driven strategies. Current methods use CNN or handmade features such symmetry analysis, alignment-based features analysis, or textural qualities. CNN approaches provide unsupervised features, while manual features model domain knowledge. Cascaded algorithms may outperform feature-based or data-driven like CNN methods. A revolutionary cascaded strategy is presented that intelligently supplies CNN with past information from handmade feature-based ML algorithms. Each patient receives manual ground truth and four MRI modalities (T1, T1c, T2, and FLAIR). Handcrafted characteristics and deep learning are used to segment brain tumors in a Global Convolutional Neural Network (GCNN). The proposed GCNN architecture with two parallel CNNs, CSPathways CNN (CSPCNN) and MRI Pathways CNN (MRIPCNN), segmented BraTS brain tumors with high accuracy. The proposed model achieved a Dice score of 87% higher than the state of the art. This research could improve brain tumor segmentation, helping clinicians diagnose and treat patients.

• Journal of Korean Neurosurgical Society
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• v.61 no.3
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• pp.363-375
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• 2018

Intraoperative monitoring (IOM) utilizes electrophysiological techniques as a surrogate test and evaluation of nervous function while a patient is under general anesthesia. They are increasingly used for procedures, both surgical and endovascular, to avoid injury during an operation, examine neurological tissue to guide the surgery, or to test electrophysiological function to allow for more complete resection or corrections. The application of IOM during pediatric brain tumor resections encompasses a unique set of technical issues. First, obtaining stable and reliable responses in children of different ages requires detailed understanding of normal age-adjusted brain-spine development. Neurophysiology, anatomy, and anthropometry of children are different from those of adults. Second, monitoring of the brain may include risk to eloquent functions and cranial nerve functions that are difficult with the usual neurophysiological techniques. Third, interpretation of signal change requires unique sets of normative values specific for children of that age. Fourth, tumor resection involves multiple considerations including defining tumor type, size, location, pathophysiology that might require maximal removal of lesion or minimal intervention. IOM techniques can be divided into monitoring and mapping. Mapping involves identification of specific neural structures to avoid or minimize injury. Monitoring is continuous acquisition of neural signals to determine the integrity of the full longitudinal path of the neural system of interest. Motor evoked potentials and somatosensory evoked potentials are representative methodologies for monitoring. Free-running electromyography is also used to monitor irritation or damage to the motor nerves in the lower motor neuron level : cranial nerves, roots, and peripheral nerves. For the surgery of infratentorial tumors, in addition to free-running electromyography of the bulbar muscles, brainstem auditory evoked potentials or corticobulbar motor evoked potentials could be combined to prevent injury of the cranial nerves or nucleus. IOM for cerebral tumors can adopt direct cortical stimulation or direct subcortical stimulation to map the corticospinal pathways in the vicinity of lesion. IOM is a diagnostic as well as interventional tool for neurosurgery. To prove clinical evidence of it is not simple. Randomized controlled prospective studies may not be possible due to ethical reasons. However, prospective longitudinal studies confirming prognostic value of IOM are available. Furthermore, oncological outcome has also been shown to be superior in some brain tumors, with IOM. New methodologies of IOM are being developed and clinically applied. This review establishes a composite view of techniques used today, noting differences between adult and pediatric monitoring.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.2
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• pp.103-115
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• 2009

In vertebrates, the face is mainly formed with neural crest derived neural crest cells by the inherent programs and the interactive environmental factors. Extracellular signaling-regulated kinase (Erk) is one of such programs to regulate the various cellular functions. And retinoic acid (RA) also plays an important role as a regulator in differentiation process at various stages of vertebrate embryogenesis. We wanted to know that the segregation as well as the patterning of maxillary and mandibular structure is greatly influenced by the maxillomandibular cleft (MMC) and the failure of this development may result in the maxillomandibular fusion (syngnathia) or other patterning related disorder. It has been well documented that the epithelium at this cleft region has significant expression of Fibroblast growth factor (Fgf) 8, and it is essential for the patterning of the first arch derived structures. By the morphological, skeletal, cell proliferation and apoptotic, and hybridization analysis, we checked the effects of Erk inhibition and/or RA activation onto MMC and could observe that Erk and RA signaling is individually and synergically involved in the facial patterning in terms of FGF signaling pathway via Barx-l. So RA and Erk signaling work together for the MMC patterning and the segregation of maxilla-mandible by controlling the Fgf-related signaling pathways. And the abnormality in MMC brought by aberrant Fgf signaling may result in the disturbances of maxillary-mandibular segregation.

• Journal of Life Science
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• v.31 no.12
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• pp.1120-1127
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• 2021

Depression has a negative impact on social functioning due to its high prevalence and increased suicide rate, and is a disease with a high economic burden. Depression is related to diverse brain-related phenomena, such as neuroinflammation, synaptic dysfunction, and cognitive deficit. As antidepressant drugs used in clinical trials have shown poor therapeutic effects, antidepressant drugs that show rapid efficacy urgently need to be developed. Although studies on various genes, proteins, and signaling pathways related to depression have been conducted, the pathogenesis of depression has not been clearly elucidated. Sirtuin 1 is a nicotinamide-adenine dinucleotide- (NAD+-) dependent histone deacetylase and is involved in cell differentiation, apoptosis, autophagy, and cancer metabolism. Recent genetic studies found that sirtuin 1 is a potential target gene for depression. In addition, preclinical studies reported that sirtuin 1 signaling affects depression-like behavior. In this review, we attempt to present up-to-date knowledge of depression and sirtuin 1. We describe the various roles of sirtuin 1 in the regulation of glial activation, circadian rhythm, neurogenesis, and cognitive function and the effects of its expression on depression. Further, we discuss the effect of sirtuin 1 on the impairment of neural plasticity, one of the key mechanisms of depression, and the associated mechanisms of sirtuin 1.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.24-25
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• 2003

The zebrafish (Danio rerio) is now the pre-eminent vertebrate model system for clarification of the roles of specific genes and signaling pathways in development. I will talk about positional cloning of two developmental mutants in zebrafish. The first mutant is headless: The vertebrate organizer can induce a complete body axis when transplanted to the ventral side of a host embryo by virtue of its distinct head and trunk inducing properties. Wingless/Wntantagonists secreted by the organizer have been identified as head inducers. Their ectopic expression can promote head formation, whereas ectopic activation of Wnt signalling during early gastrulation blocks head formation. These observations suggest that the ability of head inducers to inhibit Wntsignalling during formation of anterior structures is what distinguishes them from trunk inducers that permit the operation of posteriorizing Wnt signals. I describe the zebrafish headless (hdl) mutant and show that its severe head defects are due to a mutation in T-cell factor-3 (Tcf3), a member of the Tcf/Lef family. Loss of Tcf3 function in the hdl mutant reveals that hdl represses Wnt target genes. I provide genetic evidence that a component of the Wntsignalling pathway is essential in vertebrate head formation and patterning. Second mutant is mind bomb: Lateral inhibition, mediated by Notch signaling, leads to the selection of cells that are permitted to become neurons within domains defined by proneuralgene expression. Reduced lateral inhibition in zebrafish mib mutant embryos permits too many neural progenitors to differentiate as neurons. Positional cloning of mib revealed that it is a gene in the Notch pathway that encodes a RING ubiquitin ligase. Mib interacts with the intracellular domain of Delta to promote its ubiquitylation and internalization. Cell transplantation studies suggest that mib function is essential in the signaling cell for efficient activation of Notch in neighboring cells. (중략)

• Applied Microscopy
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• v.48 no.1
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• pp.17-26
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• 2018

The characteristic features of the arachnid central nervous system (CNS) are related to its body segmentation, and the body in the Opiliones appears to be a single oval structure because of its broad connection between two tagmata (prosoma and opisthosoma). Nevertheless, structural organization of the ganglionic neurons and nerves in the harvestman Leiobunum japonicum is quite similar to the CNS in most other arachnids. This paper describes the fine structural details of the main groups of neuropiles in the CNS ganglia revealed by the transmission electron microscopy. In particular, electron-microscopic features of neural clusters in the main neuroganglia of the CNS (supraesophageal ganglion, protocerebral ganglion, optic lobes, central body, and subesophageal ganglion) could provide indications for the nervous pathways associated with nerve terminations and plexuses. The CNS of this harvestman consists of a supraesophageal ganglion (brain) and a subesophageal mass, and there are no ganglia in the abdomen. Cell bodies of neuroganglia are found in the periphery, but central parts of the ganglia are mostly fibrous in all ganglia. Neuroglial cells occupy the spaces left by nerve cells. Since the nerve cells in the ganglia are typical composed of monopolar neurons, axons and dendrites of neurons are distributed along the same direction.

• The Korean Journal of Pain
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• v.31 no.3
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• pp.174-182
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• 2018

Background: The trigeminal nucleus caudalis (Vc) is a primary central site for trigeminal transmitting. Noxious stimulation of the trigeminal nociceptors alters the central synaptic releases and neural expression of some inflammatory and trophic agents. Orexin-A and the orexin 1 receptor (OX1R) are expressed in pain pathways including trigeminal pain transmission. However, the the mechanism(s) underling orexin-A effects on trigeminal pain modulation have not been fully clarified. Methods: Trigeminal pain was induced by subcutaneous injection of capsaicin in the upper lip in rats. The effect of trigeminal pain on cyclooxygenase-2 (COX-2) and brain-derived neurotrophic factor (BDNF) expression in the Vc of animals was determined by immunofluorescence. Subsequently, OX1R agonist (orexin-A) and antagonist (SB-334867-A) was administrated in the Vc to investigate the possible roles of the Vc OX1R on changes in COX-2 and BDNF levels following pain induction. Results: The data indicated an increase in COX-2 and decrease in BDNF immuno-reactivity in the Vc of capsaicin, and capsaicin- pretreated with SB-334867-A (80 nM), groups of rat. However, the effect of capsaicin on COX-2 and BDNF expressions was reversed by a Vc microinjection of orexin-A (100 pM). Conclusions: Overall, the present data reveals that orexin-A can attenuate capsaicin-induced trigeminal pain through the modulation of pain effects on COX-2 and BDNF expressions in the Vc of rats.

• Korean Journal of Psychosomatic Medicine
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• v.20 no.2
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• pp.135-138
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• 2012

The pathophysiology of functional gastrointestinal disorder(FGID) is not completely understood, but the importance of the 'Brain-Gut Axis(BGA)' model in FGID is being increasingly recognized. The BGA model is a bidirectional, hard-wired and homeostatic relationship between the central nervous system(CNS) and the enteric nervous system(ENS) via neural, neurohormonal and neuroimmunological pathways. In addition, the BGA model would provide a rationale for the use of psychotropics on FGID. The authors experienced two cases in which duloxetine, a serotonin-norepinephrine reuptake inhibitor, was effective in relieving FGID symptoms as well as psychiatric symptoms such as depression and hypochondriacal anxiety. Therefore we discuss the vignettes from the perspective of BGA theory. Duloxetine showed efficacy in these two patients by reducing visceral hypersensivity (bottom-up regulation) and by relieving depression and anxiety(top-down regulation).

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.8 no.2
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• pp.217-231
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• 1997

This paper first reviewed the current neurological theories concerning the etiology of ADHD and secondly, examined results of studies that applied neuropsychological assessment methods in the examination of ADHD children both here in Korea and abroad. ADHD children were found to exhibit characteristic responses indicating deficits in vigilance, sustained attention, distractibility, allocation and regulation of attention in many assessments of attention, in addition to deficits in executive functioning, working and associative memory. Such neuropsychological assessment results suggest that in addition to dysfunction in the frontal lobe and the reticular activation system, dysfunction may exist in other neural pathways involving many areas of the brain. However, because a substantial number of neuropsychological assessment tools being employed in Korea for ADHD children had been developed abroad, a Korean standardization project involving ADHD and normal control children, in addition to other child psychiatric population pools must be conducted in order to obtain appropriate age norms and test validity, and in order to make possible a more accurate and precise comparison and interpretation in the assessment of ADHD children.