Publications by authors named "Jihyun Cha"

Protein N-glycosylation plays a pivotal role in regulating biological processes and is closely associated with various disease pathologies. However, the identification of N-glycopeptides typically requires efficient enrichment and advanced mass spectrometric methods due to their low abundance and interference from non-glycosylated peptides. Herein, a boronic acid-functionalized core-shell mesoporous silica-TiO nanocomposite is proposed for selective enrichment of N-glycopeptides from biological samples.

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This study investigated the distribution and composition of persistent toxic substances in freshwater fish collected from the Gapcheon River, Daejeon, South Korea. To identify key toxicants responsible for biological effects, effect-directed analysis was applied, focusing on aryl hydrocarbon receptor (AhR) agonists. The target species included crucian carp (S1, Carassius carassius), common carp (S2, Cyprinus carpio), Far Eastern catfish (S3, Silurus asotus), barbel steed (S4, Hemibarbus labeo), and skygager (S5, Erythroculter erythropterus).

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This study investigated 63 persistent toxic substances (PTSs) in surface sediments along the Yangtze River, analyzing contamination levels, spatial distribution, sources, and ecological risks. High PTS levels were observed in Nanjing due to organic pollution, with significant regional variations in styrene oligomers (SOs), alkylphenols (APs), and polyhalogenated carbazoles (PHCZs) in Nantong, Changzhou, and Shanghai, respectively. These patterns were linked to local anthropogenic activities, with higher contamination in more densely populated and industrialized areas.

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We investigated the relationship between prefrontal functional connectivity of oxyhemoglobin and outcomes in sepsis-associated encephalopathy (SAE). Additionally, we developed a prognostic method for patients with SAE. A total of 40 consecutive patients with SAE were prospectively included.

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This study investigated the distribution and composition of 28 per- and polyfluoroalkyl substances (PFASs) in surface and core sediments from the regional seas of South Korea. Surface sediments were collected from the Yellow Sea (YS, n = 10), East China Sea (ECS, n = 6), South Sea (SS, n = 5), and East Sea (ES, n = 12), and core sediments were obtained from the ES (n = 3, 0-30 cm). Sediment samples were extracted with methanol by shaking, followed by purification using solid-phase extraction cartridges.

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There remains a scarcity of studies to evaluate the treatment effect of electroconvulsive therapy (ECT). Functional near-infrared spectroscopy (fNIRS) offers a cost-effective method to measure cerebral hemodynamics. This study used fNIRS to evaluate the effect of ECT in patients suffering from schizophrenia or bipolar disorder (manic phase).

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This study focused on analyzing the spatial and vertical distributions of 28 per- and polyfluoroalkyl substances (PFASs), which comprised five precursors and three alternatives, in the water columns of the regional seas surrounding South Korea, such as the Yellow Sea (YS, Y1-Y10), East China Sea (ECS, EC1-EC6), South Sea (SS, S1-S5), and East Sea (ES, E1-E7). The concentrations of these PFASs detected in 204 seawater samples varied from below the limit of detection ( View Article and Find Full Text PDF

Article Synopsis
  • This study focused on identifying major aryl hydrocarbon receptor (AhR) agonists found in surface sediments from Kongsfjorden, Arctic Svalbard, particularly near abandoned coal mines.
  • High levels of AhR activity were detected, especially in sediments from sites S2 and S3, with significant amounts of various polycyclic aromatic hydrocarbons (PAHs) present.
  • Findings revealed that around 24 specific AhR agonists contributed significantly to the observed toxic potential, with many being identified as coal-derived substances, emphasizing the need for more research on the ecological impacts of these contaminants.
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  • Gamcheon Harbor in Busan, South Korea, is polluted with harmful substances like polycyclic aromatic hydrocarbons and styrene oligomers, prompting a study on sediment toxicity.
  • The research utilized effect-directed analysis and non-target screening to find aryl hydrocarbon receptor (AhR)-active substances in the harbor's sediments, revealing significant potencies in specific sediment fractions.
  • Daphnoretin and isorhamnetin were identified as major AhR agonists, indicating that the toxic compounds in this coastal region are specific to the area and highlighting the importance of monitoring these substances in ecosystems.
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Transcranial photobiomodulation (tPBM) has been widely studied for its potential to enhance cognitive functions of the elderly. However, its efficacy varies, with some individuals exhibiting no significant response to the treatment. Considering these inconsistencies, we introduce a machine learning approach aimed at distinguishing between individuals that respond and do not respond to tPBM treatment based on functional near-infrared spectroscopy (fNIRS) acquired before the treatment.

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Academic achievement is a critical measure of intellectual ability, prompting extensive research into cognitive tasks as potential predictors. Neuroimaging technologies, such as functional near-infrared spectroscopy (fNIRS), offer insights into brain hemodynamics, allowing understanding of the link between cognitive performance and academic achievement. Herein, we explored the association between cognitive tasks and academic achievement by analyzing prefrontal fNIRS signals.

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  • Cognitive impairments can significantly hinder daily life and work performance, and despite many drug developments, most have failed in clinical trials, prompting interest in herbal remedies as a potential treatment for dementia.
  • The study investigated the cognitive effects of a specific herbal remedy and its compounds through various behavioral tests and their influence on key pathological targets in Alzheimer's disease, including amyloid deposition and tau hyperphosphorylation.
  • Findings suggest that the herbal remedy and its active components help improve cognitive function by reducing oxidative damage, regulating neuroinflammation, preventing cell death, and enhancing neural growth, indicating potential for future treatments in neurological disorders.
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Despite its reputation as one of the cleanest regions globally, recent studies have identified the presence of various persistent toxic substances (PTSs) in the environmental matrices collected from Svalbard. This study investigated the chronological distribution and potential sources of 81 PTSs in soils from the glacier foreland of Midtre Lovénbreen. Soil samples (n = 45) were categorized by age based on exposure to the atmosphere due to glacier retreat in July 2014 into five age groups: 80-100 years (n = 7), 60-80 years (n = 12), 40-60 years (n = 16), 20-40 years (n = 7), and <20 years (n = 3).

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Objective: The benefits of long-term consumption of green tea on the brain are well known. However, among many ingredients of green tea, the acute effects of (-)-gallocatechin gallate-rich green tea extract (GCG-GTE), have received comparatively less attention. Herein, we investigated the acute effects of oral ingestion of green tea with GCG-GTE, which contains close replicas of the ingredients of hot green tea, on task-dependent hemodynamics in the prefrontal cortex of healthy adult human brains.

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Background: As the population ages and the prevalence of dementia increases, there is a growing emphasis on the importance of cognitive training to prevent dementia. A smartphone application-based cognitive training software program, BeauBrain Trainer (BBT), has been developed to provide better access to cognitive training for older adults. Numerous studies have revealed the effectiveness of cognitive training using a cognitive assessment tool.

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Effect-directed analysis (EDA) combined with nontarget screening (NTS) has established a valuable tool for the identification of unmonitored toxic substances in environmental samples. It consists of three main steps: (1) highly potent fraction identification, (2) toxicant candidate selection, and (3) major toxicant identification. Here, we discuss the methodology, current status, limitations, and future challenges of EDA combined with NTS.

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Assessing and managing patient anxiety is essential to reduce postoperative complications in elderly patients. However, monitoring patient anxiety objectively is impossible. This study aimed to investigate the correlation between the level of fNIRS signals and anxiety in patients aged 65 and older undergoing artificial joint replacement surgery.

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  • A study examined the presence of aryl hydrocarbon receptor (AhR) agonists in the blubber, liver, and muscle of long-beaked common dolphins and a fin whale from Korea, revealing that blubber and liver had higher concentrations of these compounds.
  • Researchers identified 37 potential AhR agonists across various categories like pharmaceuticals and pesticides, with five new compounds confirmed through toxicological tests.
  • The findings highlighted significant tissue-specific accumulation of AhR agonists, showing that certain compounds like rutaecarpine and hydrocortisone majorly contributed to AhR activity in the blubber and liver, respectively.
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  • This study compares the effectiveness of functional near-infrared spectroscopy (fNIRS) with PET and MRI in detecting brain activity in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD).
  • Participants were categorized into four groups based on their cognitive status and underwent a semantic verbal fluency task, revealing distinct hemodynamic responses in the dorsolateral prefrontal cortex (DLPFC).
  • Findings suggest that fNIRS could serve as a useful screening tool for assessing brain function and metabolic changes in MCI and AD patients by correlating with other neuroimaging methods.
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Aquaculture farms have been established along the South Sea Coast of Korea, supplying most of the seafood consumed domestically. However, annual harmful algal blooms pose a potential threat to seafood safety. This study aimed to determine the spatial and seasonal distributions of 12 lipophilic marine biotoxins (LMTs) in phytoplankton and mussels in the region in 2021.

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Objective: Research on neural correlates in the prefrontal cortex (PFC) associated with self-injurious behavior has mainly been performed in adults. However, studies on adolescents are scarce. We aimed to investigate the activation and connectivity of the PFC between adolescents with self-injurious behavior (ASI) and psychiatric controls (PC) using functional near-infrared spectroscopy (fNIRS).

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Distribution and sources of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in the glacimarine sediments (35 sites) of Svalbard were investigated. PCBs (32 congeners), traditional PAHs (15 homologs), emerging PAHs (11 homologs), and alkylated PAHs (16 homologs) were widely distributed in the Svalbard sediments (ranges: below method detection limit to 20, 21 to 3600, 1.0 to 1400, and 31 to 15,000 ng g dry weight, respectively).

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Microalgal toxicants in sediments from an industrialized area (Ulsan Bay) in South Korea were identified using effect-directed analysis (EDA) with full-scan screening analysis (FSA) and microalgal bioassays with multiple endpoints. The growth rate and cell viability of three microalgae (Isochrysis galbana, Dunaliella tertiolecta, and Phaeodactylum tricornutum) were strongly inhibited following exposure to raw organic extracts of sediments from Site D5 (Woehang River). The polar fraction separated using a silica gel column significantly inhibited growth rate, esterase activity, cell membrane intensity, and chlorophyll a autofluorescence.

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Endocrine-disrupting potential was evaluated during the sewage treatment process using in vitro bioassays. Aryl hydrocarbon receptor (AhR)-, androgen receptor (AR)-, glucocorticoid receptor (GR)-, and estrogen receptor (ER)-mediated activities were assessed over five steps of the treatment process. Bioassays of organic extracts showed that AhR, AR, and GR potencies tended to decrease through the sewage treatment process, whereas ER potencies did not significantly decrease.

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The distribution characteristics of lipophilic marine biotoxins (LMTs), such as yessotoxins (YTXs) and pectenotoxins (PTXs) in phytoplankton, mussels, and commercial seafood were determined for the southern coast of South Korea. Gonyaulax spinifera and Dinophysis acuminata, which are the causative microalgae of YTXs and PTXs, were recorded during summer. Homo-YTX and PTX-2 were predominantly detected in phytoplankton (max: 5.

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