Search

Your search keyword '"Kim, Junsuk"' showing total 129 results
Start Over Author "Kim, Junsuk"
129 results on '"Kim, Junsuk"'

2. Secondary Concentration Plateau and Formation of Flow Stagnation by Ion Concentration Polarization in Microchannels

Author

Kim, Junsuk, Huh, Keon, Mani, Ali, and Kim, Sung Jae

Subjects
Physics - Fluid Dynamics, Physics - Applied Physics
Abstract

Ion transport in perm-selective media has been extensively investigated in recent years owing to its applications in advancements of fundamental understanding of nanoscale electrokinetics as well as innovative engineering applications. A key phenomenon in this context is ion concentration polarization (ICP) that occurs near perm-selective nanoporous membranes or nanochannels under dc bias. In classical settings, involving voltage-driven transport of ions through perm-selective membranes, concentration polarization is well understood as formation of steep concentration drop to reach near zero concentration (depletion layer) at the anodic side of cation-selective membranes. In contrast to this classical description, we demonstrate here that when ICP is driven in a microchannel and coupled with electroosmotic flows a long-tailed fluorescent layer in front of diffusion layer is formed, which can be characterized as an additional plateau in the concentration profile. Using a micro/nanofluidic platform, in situ visualizations, and local concentration measurements by microelectrode arrays we quantify that this plateau layer has a concentration of 60 % of bulk electrolyte concentration, regardless of the bulk concentration itself. Using a mathematical analysis of conservation laws for flow, charge, and salt, we demonstrate that this plateau region is related to the formation of a flow stagnation point due to the competition between electro-osmotic and induced pressure driven flows. Consistent with the experiments, this analysis predicts the plateau concentration to be 60% of the bulk electrolyte. Thus, this plateau concentration region completes the picture of ICP in microchannels which has drawn significant attention from the fields of electrokinetics and micro/nanofluidics.

Published
2019

5. Neural Biomarkers for Identifying Atopic Dermatitis and Assessing Acupuncture Treatment Response Using Resting-State fMRI

Author

Lee,In-Seon, Yoon,Da-Eun, Lee,Seoyoung, Kang,Jae-Hwan, Chae,Younbyoung, Park,Hi-Joon, Kim,Junsuk, Lee,In-Seon, Yoon,Da-Eun, Lee,Seoyoung, Kang,Jae-Hwan, Chae,Younbyoung, Park,Hi-Joon, and Kim,Junsuk

Abstract

In-Seon Lee,1 Da-Eun Yoon,1 Seoyoung Lee,2 Jae-Hwan Kang,3,4 Younbyoung Chae,1 Hi-Joon Park,1 Junsuk Kim5 1College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea; 2Department of Physics and Computational Radiology, Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway; 3Digital Health Research Division, Korea Institute of Oriental Medicine, Daejeon, Republic of Korea; 4Aging Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea; 5School of Information Convergence, Kwangwoon University, Seoul, Republic of KoreaCorrespondence: Junsuk Kim, School of Information Convergence, Kwangwoon University, 20 Kwangwoon-ro, Seoul, 01897, Republic of Korea, Tel +82-2-940-8477, Email junsuk.kim@kw.ac.kr Hi-Joon Park, College of Korean Medicine, Kyung Hee University, 26 Kyunghee-daero, Seoul, 02447, Republic of Korea, Tel +82-2-961-9435, Email acufind@khu.ac.krPurpose: Only a few studies have focused on the brain mechanisms underlying the itch processing in AD patients, and a neural biomarker has never been studied in AD patients. We aimed to develop a deep learning model-based neural signature which can extract the relevant temporal dynamics, discriminate between AD and healthy control (HC), and between AD patients who responded well to acupuncture treatment and those who did not.Patients and Methods: We recruited 41 AD patients (22 male, age mean ± SD: 24.34 ± 5.29) and 40 HCs (20 male, age mean ± SD: 26.4 ± 5.32), and measured resting-state functional MRI signals. After preprocessing, 38 functional regions of interest were applied to the functional MRI signals. A long short-term memory (LSTM) was used to extract the relevant temporal dynamics for classification and train the prediction model. Bootstrapping and 4-fold cross-validation were used to examine the significance of the models.Results: For the identification of AD patients and HC, we found that the supplementary

Published
2024

22. Predictive Values of Neutrophil-to-Lymphocyte Ratio, Platelet-to-Lymphocyte Ratio, and Other Prognostic Factors in Pediatric Patients With Bell's Palsy.

Author

Kim, Dong Hyun, Oh, Jae Hwan, Kim, Junsuk, Cho, Chang Hyun, and Lee, Ju Hyoung

Subjects
STEROID drugs, PREDICTIVE tests, PLATELET lymphocyte ratio, BLOOD platelets, INFLAMMATION, PEDIATRICS, RETROSPECTIVE studies, NEUTROPHIL lymphocyte ratio, BELL'S palsy, TREATMENT effectiveness, DESCRIPTIVE statistics, INFLAMMATORY mediators, ERYTHROCYTES, BLOOD testing, STATISTICAL sampling, CHILDREN
Abstract

Background and Objectives: Bell's palsy (BP) is the most frequent cause of unilateral facial paralysis, and inflammation is believed to play an important role in pathogenesis. Due to its rarity, however, no consensus has been reached regarding optimum treatment or factors affecting prognosis. In the present study, treatment outcomes and prognostic factors of BP were investigated in pediatric patients who underwent steroid therapy. The goal was to investigate the relationship between BP and inflammation using multiple inflammatory markers, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), mean platelet volume (MPV), and red cell distribution width (RDW). Materials and Methods: In all, 54 patients diagnosed with BP and 39 healthy randomly selected controls were enrolled in this retrospective study. Demographic characteristics and complete blood cell count test results were compared. In addition, prognostic factors were sought by dividing the 54 patients with BP into 2 groups according to the House-Brackmann grading system: low grade BP (grades II and III) and high grade BP (grades IV and V). Serum samples were analyzed retrospectively on initial presentation and 6 months after the symptom begins. Meaningful hematological parameters include NLR, PLR, MPV, and RDW. Results: The NLR values in the BP group were significantly higher than in the control group. The NLR value in the 2 groups of patients with BP differed significantly. The mean PLR value in the BP group was higher than in the control group; however, there were no significant differences between the low-grade and high-grade BP groups nor were there any statically significant differences in the other characteristics. Conclusion: The NLR and PLR values are readily accessible parameters that may be useful prognostic markers in pediatric patients with BP. Further studies are required to confirm these results and their utility in predicting prognosis and treating pediatric patients with BP. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

29. Heparin therapy as adjuvant treatment for profound idiopathic sudden sensorineural hearing loss.

Author

Kim, Junsuk, Jeong, Jinuk, Ha, Ryun, and Sunwoo, Woongsang

Abstract

Objectives/hypothesis: This study aimed to provide evidence of whether unfractionated heparin used as adjuvant therapy in conjunction with systemic corticosteroid therapy improves hearing recovery in patients with profound idiopathic sudden sensorineural hearing loss (ISSNHL), and to compare the effect of this treatment with those of additional intratympanic corticosteroid therapy.Study Design: Retrospective chart review.Methods: Eighty-seven patients with profound ISSNHL (≥90 dB) and who had been admitted at a tertiary referral center between 2010 and 2018 were retrospectively reviewed, 67 patients for additional intratympanic corticosteroid injection (ITSI) (ITSI group) and 21 for adjuvant heparin therapy (heparin group). Hearing recovery was evaluated by grade assessment according to the American Academy of Otolaryngology-Head and Neck Surgery criteria.Results: Of the patients in the heparin group, 42.8% recovered serviceable hearing, which was significantly higher than the recovery rates (19.7%) of those in the ITSI group. Particularly, in patients with pretreatment hearing level of 90 to 100 dB, adjuvant heparin therapy enhanced therapeutic effects with a significant hearing recovery rate of 80%. However, in patients with initial hearing level >100 dB, the rates of significant hearing recovery in the two groups were roughly equal and remained unsatisfactory (8.1% in the ITSI group and 9.1% in the heparin group).Conclusions: The results of this study suggest that the treatment of profound ISSNHL with adjuvant heparin therapy, in combination with systemic steroid therapy, results in higher hearing recovery rates when compared to combined local and systemic corticosteroid therapy, without serious complications.Level Of Evidence: 3b Laryngoscope, 130:1310-1315, 2020. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

38. Distributed functions of detection and discrimination of vibrotactile stimuli in the hierarchical human somatosensory system

Author

Kim, Junsuk, Müller, Klaus-Robert, Chung, Yoon Gi, Chung, Soon-Cheol, Park, Jang-Yeon, Bülthoff, Heinrich H., and Kim, Sung-Phil

Subjects
somatosensory cortex, vibrotactile stimulation, fMRI, ddc:610, functional specialization, hierarchical tactile processing, Neuroscience
Abstract

According to the hierarchical view of human somatosensory network, somatic sensory information is relayed from the thalamus to primary somatosensory cortex (S1), and then distributed to adjacent cortical regions to perform further perceptual and cognitive functions. Although a number of neuroimaging studies have examined neuronal activity correlated with tactile stimuli, comparatively less attention has been devoted toward understanding how vibrotactile stimulus information is processed in the hierarchical somatosensory cortical network. To explore the hierarchical perspective of tactile information processing, we studied two cases: (a) discrimination between the locations of finger stimulation, and (b) detection of stimulation against no stimulation on individual fingers, using both standard general linear model (GLM) and searchlight multi-voxel pattern analysis (MVPA) techniques. These two cases were studied on the same data set resulting from a passive vibrotactile stimulation experiment. Our results showed that vibrotactile stimulus locations on fingers could be discriminated from measurements of human functional magnetic resonance imaging (fMRI). In particular, it was in case (a) where we observed activity in contralateral posterior parietal cortex (PPC) and supramarginal gyrus (SMG) but not in S1, while in case (b) we found significant cortical activations in S1 but not in PPC and SMG. These discrepant observations suggest the functional specialization with regard to vibrotactile stimulus locations, especially, the hierarchical information processing in the human somatosensory cortical areas. Our findings moreover support the general understanding that S1 is the main sensory receptive area for the sense of touch, and adjacent cortical regions (i.e., PPC and SMG) are in charge of a higher level of processing and may thus contribute most for the successful classification between stimulated finger locations.

Published
2015

50. Investigation of cortical activation patterns in response to the inter-digit vibrotactile stimulation.

Author

Chung, Yoon Gi, Kim, Junsuk, Kim, Hyung-Sik, Chung, Soon-Cheol, Park, Jang-Yeon, and Kim, Sung-Phil

Abstract

Mechanosensation includes the detection of mechanical stimuli from mechanoreceptors and sensory signal transduction to the somatosensory cortex through neural afferents. Previous studies reported the sensory signals of flutter (5–50 Hz) and vibration (50–400 Hz) traveled through separated neural afferents of rapidly adapting type 1 (RA) and rapidly adapting type 2 (PC) respectively, and they activated the primary (S1) and secondary (S2) somatosensory cortices with spatially distinct patterns. In this study, we investigated the cortical activation patterns of S1 and S2 in response to flutter and vibration delivered onto the tips of index (D2) and little (D5) digits using functional magnetic resonance imaging (fMRI). We demonstrated that D2 provided more apparent cortical activation patterns that the event of flutter stimulation elicited contralateral S1 and bilateral S2 activation while the event of vibration stimulation mainly elicited bilateral S2 activation due to the somatotopic neural projection mechanisms of the RA and PC afferents and the density distribution of mechanoreceptors. [ABSTRACT FROM PUBLISHER]

Published
2012

Catalog

Books, media, physical & digital resources
See catalog results