Publications by authors named "Kyoungmi Jang"

Background: The stability index estimation algorithm was derived and applied to develop and implement a balance ability diagnosis system that can be used in daily life.

Methods: The system integrated an approach based on sensory function interaction, called the clinical test of sensory interaction with balance. A capacitance and resistance sensing type force mat was fabricated, and a stability index prediction algorithm was developed and applied using the center of pressure variables.

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With the increasing use of virtual reality (VR) devices, interest in reducing their negative effects, such as VR sickness, is also increasing. This study used electroencephalography (EEG) to investigate participants' VR sickness recovery time after watching a VR video. We tested 40 participants in advance using a motion sickness susceptibility questionnaire (MSSQ).

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The Wii balance board (WBB) is a simplified force plate system used to evaluate the balancing ability of the elderly via a sensory interaction task to confirm a significant standing balance index. The accuracy of this system has been verified in previous studies. In this study, an instrumented and modified clinical test of sensory interaction on balance (i-mCTSIB) was performed on 84 elderly subjects, and the variables for center of pressure (CoP) were calculated using WBB for each task condition.

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Virtual reality (VR) is a rapidly developing technology that simulates the real world. However, for some cybersickness-susceptible people, VR still has an unanswered problem-cybersickness-which becomes the main obstacle for users and content makers. Sensory conflict theory is a widely accepted theory for cybersickness.

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Background: Mild cognitive impairment (MCI) may occur due to several forms of neurodegenerative diseases and non-degenerative conditions and is associated with cognitive impairment that does not affect everyday activities. For a timely diagnosis of MCI to prevent progression to dementia, a screening tool of fast, low-cost and easy access is needed. Recent research on eye movement hints it a potential application for the MCI screening.

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Cybersickness refers to the uncomfortable side effects, such as headaches, dizziness, and nausea, felt while experiencing virtual reality (VR). This study investigated cybersickness in people with sensitivity to motion sickness using electroencephalography (EEG), the Simulator Sickness Questionnaire (SSQ), and simple VR content. Based on the scores from the Motion Sickness Susceptibility Questionnaire (MSSQ), 40 males in their twenties were selected as the sensitive group (n = 20) and non-sensitive group (n = 20).

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No reliable quantitative and objective measurement method for virtual reality (VR) sickness has been firmly established to date. Electroencephalography (EEG) may be a strong candidate to evaluate VR sickness objectively. However, no test-retest evaluation has been made for VR sickness using EEG.

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This study investigated deficits of spatial working memory in college students with attention-deficit/hyperactivity disorder (ADHD) traits using event-related potentials (ERPs) and the spatial 2-back task. We also computed sensory-level activity using EEG data and investigated theta and alpha neural oscillations, phase-locking values (PLV), and brain networks. Based on the scores from the Adult ADHD Self-Report Scale (ASRS) and Conners' Adult ADHD Rating Scales (CAARS), an ADHD-trait group ( = 40) and a normal control group ( = 41) were selected.

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This study investigated the ability to use feedback for decision-making in female college students who binge drink (BD) using the iowa gambling task (IGT) and event-related potentials (ERPs). Twenty-seven binge drinkers and 23 non-binge drinkers (non-BD) were identified based on scores on the Korean version of the Alcohol Use Disorder Test and the Alcohol Use Questionnaire. The IGT consists of four cards, including two cards that result in a net loss, with large immediate gains but greater losses in the long term, and two cards that result in a net gain, with small immediate gains but reduced losses in the long term.

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The study of non-clinical individuals with schizotypal traits has been considered to provide a promising endophenotypic approach to understanding schizophrenia, because schizophrenia is highly heterogeneous, and a number of confounding factors may affect neuropsychological performance. Here, we investigated whether deficits in explicit verbal memory in individuals with schizotypal traits are associated with abnormalities in the local and inter-regional synchrony of brain activity. Memory deficits have been recognized as a core problem in schizophrenia, and previous studies have consistently shown explicit verbal memory impairment in schizophrenic patients.

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The present study used event-related potentials (ERPs) to investigate deficits in error-monitoring by college students with schizotypal traits. Scores on the Schizotypal Personality Questionnaire (SPQ) were used to categorize the participants into schizotypal-trait (n = 17) and normal control (n = 20) groups. The error-monitoring abilities of the participants were evaluated using the Simon task, which consists of congruent (locations of stimulus and response are the same) and incongruent (locations of stimulus and response are different) conditions.

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This paper investigates the importance of substituent placement when designing low-molecular mass π-organogelators. The electron-deficient NO2 substituent was systematically added to novel T-shaped phenazines to examine electronic as well as assembly properties. This T-shaped molecular platform promotes selective electronic tuning, which can be theoretically analyzed by examining the system's frontier molecular orbitals.

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Previous studies have reported that repetitive transcranial magnetic stimulation (rTMS) induces neuronal plasticity in the brain. Although event-related potential (ERP) is an exploration tool, the rTMS effects on ERPs in patients with major depression have not been fully explored. We demonstrated that rTMS treatment induces changes in brain function in patients with medication-resistant major depression using the ERP.

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We examined local-global visual processing in college students with schizotypal traits using event-related potentials (ERPs). Local-global processing was assessed using a divided-attention task, in which large numbers (global level) composed of small numbers (local level) were presented. The control group had faster response time (RT) and more accurate responses to global-level than to local-level stimuli, whereas RT and accuracy did not differ between levels in the schizotypal-trait group.

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This paper reports novel pyrazine-acenes containing electron-deficient heteroaromatic π-extenders, such as pyridine, pyrazine, and benzothiadiazole, directly fused with pyrazine. Electronic properties of these systems were characterized by UV-Vis, fluorescence spectroscopy, and cyclic voltammetry. Computational electronic property evaluation of all experimentally synthesized compounds is provided, and is coupled with electronic calculations of closely related compounds that were not synthetically feasible.

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Background: We investigated the electrophysiological correlates of object-repetition effects using an object categorization task, standardized low-resolution electromagnetic tomography (sLORETA), and individual magnetic resonance imaging. Sixteen healthy adults participated, and a total of 396 line drawings of living and non-living objects were used as stimuli. Of these stimuli, 274 were presented only once, and 122 were repeated after one to five intervening pictures.

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In this paper, we report self-assembly of tetrachloroacenes containing pyrazine moieties. The title compounds, phenazine and bisphenazine substituted with four chlorine atoms for increased electron deficiency and alkyloxy side groups for solubility, demonstrated excellent gelation ability in select organic solvents. The assembled structure of these two series of compounds exhibited a morphological difference.

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The current study employs both theoretical and experimental methods to characterize the electronic properties associated with peripheral substitution on asymmetric phenazine and bisphenazine systems. Substituent groups include F, Cl, Br, and NO(2) with substitutions made at different positions on the heteroaromatic rings in order to assess the effects of substituent type as well as substituent position on the electronic properties. A comprehensive investigation on halogen substituents was conducted to determine the efficacy of either Cl or Br, specifically these substituents' ability to lower LUMO energies relative to F.

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This paper reports the electronic and organogelation properties of novel T-shaped bisphenazines functionalized with alkyl side groups and small peripheral cyano (CN) or aldehyde (CHO) substituents. UV-vis spectroscopy and cyclic voltammetry show the effect of the position, type, and number of the peripheral substituents on the electronic properties of the entire system. Interesting organogelation properties including a thixotropic behavior were observed from these T-shaped bisphenazines.

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Tuning electronic properties and morphologies: We report a unique design platform of n-type organic semiconductors based on asymmetrically substituted bisphenazines that enable tuning of both electronic properties and morphologies of 1D nanostructures (see figure) by using small substituents with various sizes and electronic demands.This paper reports the synthesis and characterization of novel self-assembling n-type organic semiconductors based on asymmetrically substituted bisphenazines with various functional groups of different size, electron-withdrawing ability, and conjugation length. The overarching objective of this research is to tune electronic properties and morphologies of self-assembled structures of this system simultaneously, which offers a potentially useful platform for future optoelectronic applications.

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We investigated the neuropsychological profile of subjects in a subclinical obsessive-compulsive disorder (OCD) sample. Psychometrically defined subclinical obsessive-compulsive (n = 21) and control (n = 22) subjects were examined. Comprehensive neuropsychological tests evaluating verbal/nonverbal memory, attention, and executive function were administered.

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This paper reports the formation of an organogel of an asymmetric bisphenazine through the growth of one-dimensional nanofibers via a coopertive interplay of pi-pi interaction, hydrogen bonding, and van der Waals interaction and the colorimetric acid sensing property of the nanofibers.

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