49 results on '"Ji Hye Kwak"'
Search Results
2. Intraoperative Facial Nerve Monitoring during Parotidectomy: The Current Practices and Patterns of the Korean Society of Head and Neck Surgery (KSHNS)
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Dongbin Ahn, Ji Hye Kwak, Geun-Jeon Kim, Heejin Kim, Dong Won Lee, and Kwang Jae Cho
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parotid ,facial nerve ,palsy ,electromyography ,monitoring ,Medicine (General) ,R5-920 - Abstract
Objectives: This study aimed to evaluate the current practices and trends of intraoperative facial nerve (FN) monitoring (IOFNM) during parotidectomy. Methods: A questionnaire containing 33 questions collecting information on the usage, indications, settings, techniques, loss of signal (LOS) management, anesthesiologist cooperation, and perception of usefulness of IOFNM was distributed among 348 members of the Korean Society of Head and Neck Surgery (KSHNS) via a dedicated website. Results: The response rate was approximately 25.6%, and 97% of the respondents reported using IOFNM selectively or routinely during parotidectomy. IOFNM usage decreased as the surgeon’s level of experience increased (p = 0.089), from 100% in those with less than 5 years of experience to 75% in those with 20 or more years. Approximately 95% of respondents reported that the initial event threshold for electromyography activity used was 50–149 μV. Moreover, 52.4% of respondents performed neural mapping of the FN before visual identification. Initial management of LOS in visually intact FNs included checking the IOFNM system (75.3%), confirmation of muscle relaxant dosage (75.3%), and facial twitch identification (58.8%). Further management included proceeding with surgery regardless of persistent LOS (81.2%) and steroid administration sometimes or all of the time (72.9%). Overall, 98.8% of respondents found IOFNM beneficial for safe execution of parotidectomy. Conclusions: The majority of KSHNS surgeons used IOFNM during parotidectomy, although the clinical implementation of the procedure and LOS management varied between practitioners. This could be attributed to the lack of standardized protocols for IOFNM, emphasizing the need for the development of evidence-based consensus guidelines for all institutions.
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- 2024
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3. Parathyroidectomy for primary hyperparathyroidism: A retrospective analysis of localization, surgical characteristics, and treatment outcomes
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Dongbin Ahn, Ji Hye Kwak, Gil Joon Lee, and Jin Ho Sohn
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Localization ,Parathyroidectomy ,parathyroid hormone ,Primary hyperparathyroidism ,Surgery ,RD1-811 - Abstract
Objective: To evaluate parathyroidectomy for primary hyperparathyroidism (PHPT) regarding localization, surgical characteristics, and treatment outcomes. Methods: Seventy-eight patients who underwent parathyroidectomy for PHPT were retrospectively reviewed. The results were analyzed according to intraoperative localization technique (IOLT), intraoperative parathyroid hormone (IOPTH) monitoring, and intraoperative nerve monitoring (IONM). The localization accuracy of ultrasonography (US), computed tomography (CT), and single-photon emission computed tomography (SPECT)-CT with sestamibi Tc99m was evaluated. Results: Parathyroidectomy was successfully completed in all 78 patients, achieving 100% surgical cure. For 60 patients with IOPTH monitoring, 10-min IOPTH decreased >50% from baseline in 57 (95.0%), and they achieved surgical cure. In the remaining three (5.0%) patients with ≤50% decrease in 10-min IOPTH, 20-min IOPTH decreased >50% from baseline in two (3.3%) patients, achieving surgical cure without additional neck exploration. There were no differences in surgical cure and complications as a function of IOLT use or IOPTH monitoring. Operating time was significantly shorter with IOLT and IOPTH monitoring than without (IOLT: 70.9 min vs. 88.0 min, p = 0.013; IOPTH: 74.9 min vs. 91.9 min, p = 0.037). All 78 patients had adenoma including one patient with a double adenoma. Vocal cord paralysis was not observed in our series, regardless of IONM. US, CT, and SPECT-CT localized the pathological parathyroid gland accurately in 88.1%, 85.5%, and 86.8% of patients, respectively (p = 0.894). Conclusion: The surgical outcomes of parathyroidectomy for PHPT were excellent regardless of IOLT and IOPTH monitoring. However, these techniques can maximize the performance of parathyroid surgery by reducing operating time and rescuing challenging cases.
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- 2023
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4. Severe Upper Gastrointestinal Bleeding in Patients on Antithrombotic Therapy
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Ji Hye Kwak, Cha Young Kim, Hong Jun Kim, Chang Yoon Ha, Hyun Jin Kim, Tae Hyo Kim, and Ok-Jae Lee
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Upper gastrointestinal hemorrhage ,Antithrombotic therapy ,Endoscopy ,Hemostasis ,Internal medicine ,RC31-1245 - Abstract
Background/Aims: As the elderly population taking antithrombotic therapy (ATT) increases, gastrointestinal (GI) bleeding risk during ATT may likely increase. This study was conducted to evaluate the clinical characteristics of severe upper GI bleeding (UGIB) during ATT. Materials and Methods: Among patients on ATT at Gyeongsang National University Hospital between March 2005 and February 2010, those with severe UGIB requiring endoscopic hemostasis were selected for the study. Their medical records were retrospectively reviewed for clinical variables. Results: Among 59,773 patients taking ATT, 125 (0.21%) developed severe UGIB and comprised 12.8% of the overall endoscopic hemostasis cases (125/978) during the same period. The patients with severe UGIB on ATT were older than the ones not on ATT (68.3 vs. 59.9 years, P<0.001). The common indications for ATT were cardiovascular (60.8%, 76/125) and cerebrovascular diseases (25.6%, 32/125). Fifty-nine patients (47.2%) were taking two or more agents, 36 (28.8%) were on aspirin monotherapy, while 22 (17.6%) were taking warfarin alone. Aspirin was involved in 68.8% (86/125) of severe UGIB. According to ATT type, the incidence of severe UGIB was 0.48% with warfarin, 0.38% with aspirin, and 0.33% with clopidogrel. The main causes of severe UGIB were gastric (78, 62.4%) and duodenal ulcers (15, 12.0%). UGIB recurred in 11 cases (8.8%), but all were successfully controlled with repeated hemostasis and there was no mortality. Conclusions: The frequency of severe UGIB during ATT was 0.21%. Aspirin was the most common agent leading to severe UGIB, but its incidence was highest with warfarin. Gastric ulcer was the most common focus. Endoscopic hemostasis was effective and safe for UGIB during ATT.
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- 2017
- Full Text
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5. Ultrasound‐Guided Ethanol Ablation as a Primary Treatment for Thyroglossal Duct Cyst: Feasibility, Characteristics, and Outcomes
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Dongbin Ahn, Ji Hye Kwak, Gil Joon Lee, and Jin Ho Sohn
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Otorhinolaryngology ,Surgery - Published
- 2023
6. Development of a Compression Inner Layer Attachable to Dress Shirts for Gynecomastia Sufferers
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Eunah Yoh and Ji-Hye Kwak
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Polymers and Plastics ,Arts and Humanities (miscellaneous) ,Materials Science (miscellaneous) ,Human Factors and Ergonomics ,Industrial and Manufacturing Engineering ,Social Sciences (miscellaneous) - Published
- 2022
7. A Case of Laryngeal Amyloidosis: Role of US and US-CNB for Preoperative Diagnosis
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Dongbin Ahn, Eun Jung Oh, Ji Hye Kwak, and Jin Ho Sohn
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Otorhinolaryngology ,Surgery - Abstract
Amyloidosis is a rare benign disease characterized by the extracellular deposition of nonsoluble fibrillar proteins (amyloids) within organs. Laryngeal amyloidosis (LA) accounts for only 9%-15% of all cases of amyloidosis. Since clinical manifestations and laryngoscopic findings often overlap with those of laryngeal cancer, it is challenging to differentiate LA from laryngeal cancer prior to surgical biopsy. We report a case of LA mimicking laryngeal cancer, in which the diagnosis was facilitated by preoperative ultrasonography (US) and US-guided core-needle biopsy (US-CNB) prior to surgical biopsy. The US findings of this case were distinguishable from those of laryngeal cancer, which enabled us to consider a diagnosis other than laryngeal cancer. Amyloidosis was diagnosed preoperatively using office-based percutaneous US-CNB, avoiding general anesthesia needed for suspension laryngoscopic examination. This case suggests that US and US-CNB could be used as supplementary diagnostic modalities to evaluate suspicious laryngeal masses mimicking laryngeal cancer.
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- 2022
8. A Case of Thyroid Abscess Following Ethanol Ablation for Benign Thyroid Nodule
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Heungrae Cho, Dongbin Ahn, Ji Hye Kwak, and Gil Joon Lee
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Otorhinolaryngology ,Surgery - Published
- 2023
9. Role and Recent Trend of Intraoperative Parathyroid Hormone Monitoring During Parathyroidectomy in Patients With Primary Hyperparathyroidism
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Dongbin Ahn and Ji Hye Kwak
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Otorhinolaryngology ,Surgery - Abstract
In the last few decades, the standard surgical treatment for primary hyperparathyroidism (PHPT) has shifted from bilateral neck exploration to focused/minimally invasive parathyroidectomy (FMIP). This shift was accelerated by the introduction of intraoperative parathyroid hormone (IOPTH) monitoring, which can provide intraoperative information regarding the localization and complete excision of the pathological parathyroid gland during FMIP. Since the first clinical application of the IOPTH assay in 1991, IOPTH monitoring has substantially improved to date to increase its performance and availability. In addition, the clinical applications of IOPTH changed with the needs of actual clinical practice, although the fundamental concept and technique remained unchanged. In this review, we discuss the role of IOPTH monitoring in the surgical management of PHPT based on the results of contemporary studies and summarized the major issues regarding IOPTH.
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- 2022
10. Hierarchical copper nanostructures synthesized on microparticles for improved photothermal conversion in photonic sintering of copper-based printed electrodes
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Jae-Won Lee, Juhee Kim, Ji Hye Kwak, Jung Hoon Kim, Sooyeon Jeong, Joong Tark Han, Geon-Woong Lee, Kang-Jun Baeg, Kyong-Soo Hong, Imjeong H.-S. Yang, and Hee Jin Jeong
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Materials Chemistry ,General Chemistry - Abstract
Photonic sintering of Cu-particle-based printed patterns using intense pulsed light (IPL) is a promising route to the large-scale fabrication of printed electronics for commercial applications.
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- 2022
11. Evaluation of Carotid Space Schwannoma Using Ultrasonography: Characteristics and Role in Defining the Nerve of Origin
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Dongbin Ahn, Ji Hye Kwak, Gil Joon Lee, and Jin Ho Sohn
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Parapharyngeal Space ,Radiological and Ultrasound Technology ,Humans ,Vagus Nerve ,Radiology, Nuclear Medicine and imaging ,Prospective Studies ,Neurilemmoma ,Ultrasonography - Abstract
We aimed to evaluate the ultrasonography (US) characteristics of carotid space schwannoma and their role in identifying the nerve of origin.This prospective study enrolled patients with cervical carotid space schwannoma accessible by US. The US characteristics of vagus nerve schwannomas (VNSs) and sympathetic nerve schwannomas (SNSs) were assessed; a carotid space schwannoma was defined as a VNS if the tumor originated in the mid-vagal region and an SNS if it arose posterior to the intact vagus nerve, displacing the vagus nerve anteriorly.Twenty patients with carotid space schwannoma were enrolled. The vagus and sympathetic nerves were identified as the nerve of origin in 12 and 8 patients, respectively. VNSs were centered at levels II, III, and IV in 5, 3, and 4 patients, respectively, while SNSs were centered at levels II (7 patients) and IV (1 patient) (P = .105). The maximal diameters were 3.2 and 4.8 cm for VNSs and SNSs, respectively (P = .011). Internal vascularity was absent and low in 9 and 3 VNSs, respectively, and low and intermediate in 4 SNSs each (P = .002). Twelve patients with VNSs underwent active surveillance without immediate surgery; no adverse events occurred during the 55.2-month follow-up period. Eight patients with potential SNSs underwent surgery, confirming the sympathetic nerve as the nerve of origin.US facilitates identification of the nerve of origin in cervical carotid space schwannoma. VNSs are more frequent in infrahyoid locations and tend to be smaller in size with lower vascularity compared with SNSs on US.
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- 2021
12. Forebrain glutamatergic neuron-specific Ctcf deletion induces reactive microgliosis and astrogliosis with neuronal loss in adult mouse hippocampus
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Kyungmin Lee and Ji-Hye Kwak
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Male ,CCCTC-Binding Factor ,Neuronal death ,Glutamic Acid ,Astrogliosis ,Hippocampal formation ,Biology ,Microgliosis ,Biochemistry ,Hippocampus ,Article ,Ctcf ,Glutamatergic ,Mice ,Prosencephalon ,medicine ,Animals ,Gliosis ,Molecular Biology ,Mice, Knockout ,Neurons ,Cell Death ,Dentate gyrus ,General Medicine ,medicine.disease ,Cell biology ,medicine.anatomical_structure ,nervous system ,CTCF ,Astrocytes ,Forebrain ,Neuron ,Microglia - Abstract
CCCTC-binding factor (CTCF), a zinc finger protein, is a transcription factor and regulator of chromatin structure. Forebrain excitatory neuron-specific CTCF deficiency contributes to inflammation via enhanced transcription of inflammation-related genes in the cortex and hippocampus. However, little is known about the long-term effect of CTCF deficiency on postnatal neurons, astrocytes, or microglia in the hippocampus of adult mice. To address this, we knocked out the Ctcf gene in forebrain glutamatergic neurons (Ctcf cKO) by crossing Ctcf-floxed mice with Camk2a-Cre mice and examined the hippocampi of 7.5-10-month-old male mice using immunofluorescence microscopy. We found obvious neuronal cell death and reactive gliosis in the hippocampal cornu ammonis (CA)1 in 7.5-10-month-old cKO mice. Prominent rod-shaped microglia that participate in immune surveillance were observed in the stratum pyramidale and radiatum layer, indicating a potential increase in inflammatory mediators released by hippocampal neurons. Although neuronal loss was not observed in CA3, and dentate gyrus (DG) CTCF depletion induced a significant increase in the number of microglia in the stratum oriens of CA3 and reactive microgliosis and astrogliosis in the molecular layer and hilus of the DG in 7.5-10-month-old cKO mice. These results suggest that long-term Ctcf deletion from forebrain excitatory neurons may contribute to reactive gliosis induced by neuronal damage and consequent neuronal loss in the hippocampal CA1, DG, and CA3 in sequence over 7 months of age. [BMB Reports 2021; 54(6): 317-322].
- Published
- 2021
13. Primary concurrent chemoradiation therapy with triweekly cisplatin as a standard protocol in patients aged ≥65 years with head and neck squamous cell carcinoma
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Dongbin Ahn, Ji Hye Kwak, Gil Joon Lee, Jin Ho Sohn, and Jeong Eun Lee
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Oncology ,General Medicine - Abstract
To evaluate the results of primary concurrent chemoradiation therapy (CCRT) with triweekly cisplatin in patients with head and neck squamous cell carcinoma (HNSCC) aged ≥65 years by comparing these patients to those aged 65 years.This prospective, single-center study enrolled patients with HNSCC for whom CCRT was indicated as the primary treatment. The major endpoints were progression-free survival (PFS) and overall survival (OS).A total of 169 patients were enrolled; 75 (44.4%) and 94 (55.6%) patients were aged ≥65 and 65 years, respectively. The mean cumulative cisplatin doses were 192.8 mg/mCCRT with a triweekly cisplatin regimen could act as the standard of ca for HNSCC in elderly patients. However, the relatively lower OS compared to younger patients should be acknowledged, despite a favorable disease control rates.
- Published
- 2022
14. A study on complex effects of brand slogan message appeal types and product types on brand attitude and purchase intention
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Ji Hye Kwak
- Subjects
Slogan ,Product involvement ,Appeal ,Advertising ,Business ,Product type - Published
- 2021
15. Congruity between the effect of sports apparel brand slogan and self-image on slogan and brand attitude - Moderating effect of self-monitoring
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Ji-hye Kwak
- Subjects
Descriptive statistics ,business.industry ,media_common.quotation_subject ,Identity (social science) ,Advertising ,Clothing ,Self-image ,Exploratory factor analysis ,Slogan ,Self-monitoring ,Survey data collection ,business ,Psychology ,media_common - Abstract
The purpose of this study was to investigate brand slognas that are effective in explaining how brand identity affects consumers. The effect of congruity between brand slogan and self-image (low and high) on attitude to slogans and brands were anaylzed. The moderating effect of self-monitoring (low and high) was also investigated. Survey data from 177 people in their 20s-30s were analyzed through descriptive statistics, exploratory factor analysis, and two-way ANOVA. First, congruity between slogan and self-image had a positive effect on both slogan and brand attitude. In other words, the higher the congruity between slogan and self-image, the more positive the attitude toward the slogan and brand. Second, no interactive effect was found in congruity between slogan and self-image and self-monitoring on slogan attitude; however it was identified for brand attitude. Again, in a group with high congruity between slogan and self-image, attitude toward the brand was more positive when self-monitoring was higher than when it was low. In conclusion, brand slogans that can represent the self-image of highly self-monitoring consumers are effective. In particular, this is meaningful as it has revealed its relationship with the impact of identity self-image congruity and self-monitoring on brand attitudes in fashion brands. These results offer meaningful guidance in determining brand slogans according to consumers’ personal characteristics.
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- 2021
16. How Instagram usage time and spending on fashion products affects product attitude and purchase intention according to influencer type
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Ji-hye Kwak and Eunah Yoh
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Descriptive statistics ,Interactive effects ,Advertising ,Product (category theory) ,Research findings ,Psychology ,Exploratory factor analysis - Abstract
This study examined the effect of Instagram usage time (short, long) and spending on fashion products (light, heavy) on product attitude and purchase intention of products promoted by an influencer. The moderating effect of influencer type (mega, macro, micro) was also investigated. A total of 515 males and females in their 20s participated in an online survey. Descriptive statistics were analyzed and exploratory factor analysis and two-way ANOVA were conducted. Research findings were as follows. First, the usage time, both short and long, had a positive effect on product attitude. Also, the interactive effects of usage time and influencer type on product attitude were found. Consumers with short Instagram usage time displayed the highest attitude toward products promoted by a macro-influencer whereas consumers with long Instagram usage time displayed the highest attitude toward products promoted by a micro-influencer. Second, usage time and influencer type did not show interactive effects on purchase intention. Third, both categoriacl variables of users’ spending on fashion products had a positive effect on product attitude. Fourth, the interaction effects of spending on fashion products and influencer types on purchase intention were found. The group of light buyers showed the highest purchase intention on products promoted by the macro-influencer while the group of heavy buyers showed the highest purchase intention of products promoted by the micro-influencer. Based on the results, implications were suggested.
- Published
- 2020
17. Efficient oxidation and rational reduction of long carbon nanotubes for multifunctional superhydrophobic surfaces
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Jong Hwan Park, Ji Won Wang, Seon Hee Seo, Jung Hoon Kim, Hee Jin Jeong, Jae-Won Lee, Joon Young Cho, Seung Yol Jeong, Geon-Woong Lee, Joong Tark Han, Sun-Shin Jung, Ho Young Kim, Hye Jin Yang, and Ji Hye Kwak
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Fabrication ,Materials science ,02 engineering and technology ,General Chemistry ,Thermal treatment ,Carbon nanotube ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Nanomaterials ,law.invention ,Contact angle ,Chemical engineering ,law ,General Materials Science ,0210 nano-technology ,Joule heating ,Science, technology and society ,Deoxygenation - Abstract
The inclusion of conducting nanomaterials in superhydrophobic surfaces can widen their potential applications in terms of Joule heating, electromagnetic interference shielding, oil/water separation, and self-cleaning. Here, we demonstrate the fabrication of multifunctional superhydrophobic surfaces using dispersant-free conducting inks containing highly oxidized long multiwalled carbon nanotubes (Ox-LMWCNTs). Superhydrophobic surfaces with a high water contact angle (WCA) (>150°) were realized by deposition of a perfluorosilane sol and silica nanoparticle mixture solution onto the Ox-LMWCNT surface and subsequent thermal treatment. Importantly, the electrical conductivities of the Ox-LMWCNT films were dramatically increased from 78 S/m to more than 2000 S/m by thermal deoxygenation, even at low temperatures (
- Published
- 2020
18. Microwave-assisted evolution of WO3 and WS2/WO3 hierarchical nanotrees
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Kaliannan Thiyagarajan, Ji Hye Kwak, Jong Kyu Kim, Anupam Giri, Sunshin Jung, Jaerim Kim, Sang-Mun Jung, Noho Lee, Yong-Tae Kim, Junghyeok Kwak, and Unyong Jeong
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Nanostructure ,Materials science ,Renewable Energy, Sustainability and the Environment ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochromic devices ,01 natural sciences ,Microwave assisted ,Structural evolution ,0104 chemical sciences ,Catalysis ,Electric field ,Microwave irradiation ,Electrode ,General Materials Science ,0210 nano-technology - Abstract
Although branched WO3 nanostructures have been investigated for electrochromic devices and catalytic electrodes, a detailed study on their structural evolution mechanism has rarely been carried out. In this work, we have demonstrated the microwave-assisted synthesis of branched WO3 nanotrees consisting of [001]-oriented WO3 needle-like structures growing radially from the surface of WO3 nanohelixes. The mechanism for the evolution of WO3 nanotrees with the preferred orientation was systematically investigated in terms of the reaction temperature and the distribution of the electric field applied by microwave irradiation. In addition, it was shown that the WO3 nanotrees can be easily converted into WS2/WO3 hierarchical nanotrees by a simple sulfurization process, and used as an efficient catalytic electrode for the hydrogen evolution reaction.
- Published
- 2020
19. Ultrasonography for masses of the pharynx and larynx and assessment of laryngeal squamous cell carcinoma
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Dongbin Ahn, Ji Hye Kwak, Gil Joon Lee, and Jin Ho Sohn
- Subjects
Squamous Cell Carcinoma of Head and Neck ,General Medicine ,Otorhinolaryngology ,Head and Neck Neoplasms ,Thyroid Cartilage ,Carcinoma, Squamous Cell ,Humans ,Pharynx ,Surgery ,Neoplasm Invasiveness ,Larynx ,Laryngeal Neoplasms ,Neoplasm Staging ,Ultrasonography - Abstract
To evaluate the ultrasonography (US) characteristics of pharyngeal/laryngeal masses and the role of US in the assessment of laryngeal squamous cell carcinoma (LSCC).This study enrolled patients who underwent US for evaluation of pharyngeal/laryngeal masses between 2018 and 2021. Characteristics of pharyngeal/laryngeal masses and subsite invasion in cases of LSCC were evaluated using US.Forty-six patients with pharyngeal (n = 22) /laryngeal (n = 24) masses were enrolled. The pathological results were benign and malignant in 7 (15.2%) and 39 (84.8%) patients, respectively. Malignant masses were significantly associated with US characteristics of heterogeneity (P = 0.002), irregular/speculated margin (P0.001), and increased internal vascularity (P = 0.014) compared with benign masses. In patients with LSCC, the detection rate of US for subsites invasion, including that of the anterior commissure, paraglottic space, outer cortex of the thyroid cartilage, cricoid cartilage, and extralaryngeal soft tissue, was similar to that of computed tomography (CT). Although the difference was not statistically significant, US more frequently demonstrated invasion of the inner cortex of the thyroid cartilage than CT (40.9% vs. 22.7%; P = 0.195). US and CT had a concordance rate of 81% (18 of 22 patients) in determining the tumour stage of the lesions.US could facilitate differentiation between benign and malignant masses of the pharynx and larynx in selective patients and has a possible role in the assessment of LSCC.
- Published
- 2021
20. Autophagy activity contributes to the impairment of social recognition in Epac2−/− mice
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Kyungmin Lee, Mi-Hee Jun, Hyunhyo Seo, Jin-A Lee, Ji-Hye Kwak, Juhyun Lee, Mootaek Roh, and You-Kyung Lee
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0301 basic medicine ,Transgene ,ATG5 ,Cellular homeostasis ,Biology ,Micro Report ,Mice ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Epac2 ,0302 clinical medicine ,Autophagy ,Animals ,Guanine Nucleotide Exchange Factors ,Social Behavior ,RC346-429 ,Molecular Biology ,PI3K/AKT/mTOR pathway ,Behavior, Animal ,TOR Serine-Threonine Kinases ,Neurodevelopmental disorders ,Phenotype ,Cell biology ,030104 developmental biology ,Social recognition ,Neurology. Diseases of the nervous system ,Psychopharmacology ,Flux (metabolism) ,030217 neurology & neurosurgery ,Signal Transduction - Abstract
Autophagy is a lysosomal degradation pathway that regulates cellular homeostasis. It is constitutively active in neurons and controls the essential steps of neuronal development, leading to its dysfunction in neurodevelopmental disorders. Although mTOR-associated impaired autophagy has previously been reported in neurodevelopmental disorders, there is lack of information about the dysregulation of mTOR-independent autophagy in neurodevelopmental disorders. In this study, we investigated whether the loss of Epac2, involved in the mTOR-independent pathway, affects autophagy activity and whether the activity of autophagy is associated with social–behavioral phenotypes in mice with Epac2 deficiencies. We observed an accumulation of autophagosomes and a significant increase in autophagic flux in Epac2-deficient neurons, which had no effect on mTOR activity. Next, we examined whether an increase in autophagic activity contributed to the social behavior exhibited in Epac2−/− mice. The social recognition deficit observed in Epac2−/− mice recovered in double transgenic Epac2−/−: Atg5+/− mice. Our study suggests that excessive autophagy due to Epac2 deficiencies may contribute to social recognition defects through an mTOR-independent pathway.
- Published
- 2021
21. A Case of Myeloid Sarcoma Mimicking Otomastoiditis with Retroauricular Abscess
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Hyun Ju Lee, Ji Hye Kwak, Kyu-Yup Lee, and Da Jung Jung
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Pathology ,medicine.medical_specialty ,business.industry ,Temporal bone ,Myeloid sarcoma ,medicine ,General Medicine ,medicine.disease ,business ,Abscess - Published
- 2019
22. A relationship between the body image and daily stress for a dance program participants
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Ji-hye Kwak, Jee In Yoon, and Ji-hye Kim
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Dance ,Applied psychology ,Daily stress ,Psychology - Published
- 2019
23. Microwave-welded single-walled carbon nanotubes as suitable electrodes for triboelectric energy harvesting from biomaterials and bioproducts
- Author
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Do-Hyung Kim, Jong Hoon Jung, Dae Sol Kong, Ji Hye Kwak, Minbaek Lee, Jong Hun Kim, Moonkang Choi, Sun-Shin Jung, Dong Woo Lee, Hyun Soo Kim, Gwan Hyoung Lee, Jinhong Park, and Dong Yeong Kim
- Subjects
Battery (electricity) ,Materials science ,Renewable Energy, Sustainability and the Environment ,Nanogenerator ,Nanotechnology ,02 engineering and technology ,Surface finish ,Carbon nanotube ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Evaporation (deposition) ,0104 chemical sciences ,law.invention ,law ,Electrode ,General Materials Science ,Electrical and Electronic Engineering ,0210 nano-technology ,Energy harvesting ,Triboelectric effect - Abstract
Biomaterials and bioproducts have unique characteristics of being renewable, abundant, biodegradable, and having rough surfaces. In order to implement them into highly efficient triboelectric nanogenerator (TENG) applications, the contact electrode should be cheap, flexible, able to withstand outdoor environments, and have a rough surface. Here, microwave-welded single-walled carbon nanotubes (SWCNTs) are shown to effectively harvest the mechanical vibrational energy from biomaterials and bioproducts. Selective and flash microwave heating provides firm welding of SWCNTs to a polycarbonate substrate without significant losses in flexibility, transparency, and electrical conductivity. Microwave-welded SWCNT electrodes were successfully deployed as single-electrode TENGs to harvest energy from cellulose film, hanji paper, and cherry leaf. The cellulose- and paper-based TENGs showed the quite stable triboelectric outputs even after excessive contacts and a long period of time. The leaf-based TENG showed the significantly modified triboelectric outputs due to the moisture evaporation induced shrinkage and roughness of the surface. The SWCNT electrode generated ca. ten- and two-fold larger voltage and current, respectively, than those obtained using an indium-tin oxide (ITO) electrode. Using a fan-shaped leaf-based TENG, multiple light emitting diodes and a cellular phone were successfully powered without a battery. This work implies that the microwave-welded SWCNT electrode with rough pored surface and strong resistance against environmental shocks could be a good candidate for the outdoor biomaterials and indoor bioproducts implemented TENGs to harness random- and low-frequency vibrational energy.
- Published
- 2019
24. Comparison of the Facelift Incision versus V-Shaped Incision for Parotidectomy
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Jin Ho Sohn, Ji Hye Kwak, Dongbin Ahn, Gil Joon Lee, and Jae Young Lee
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medicine.medical_specialty ,Otorhinolaryngology ,business.industry ,Medicine ,Parotid Neoplasms ,Surgery ,Surgical wound ,Parotidectomy ,business - Published
- 2019
25. Perseverative stereotypic behavior of Epac2 KO mice in a reward-based decision making task
- Author
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Mootaek Roh, Thomas J. McHugh, Ji-Hye Kwak, Kyungmin Lee, Hyunhyo Seo, Pojeong Park, Hyun Jung Lee, Ja Eun Choi, Juhyun Lee, Chae-Seok Lim, and Bong-Kiun Kaang
- Subjects
0301 basic medicine ,Cellular activity ,Patch-Clamp Techniques ,Dopamine ,Decision Making ,Prefrontal Cortex ,Striatum ,Biology ,03 medical and health sciences ,Neural activity ,Mice ,0302 clinical medicine ,Reward ,Interneurons ,medicine ,Animals ,Patch clamp ,General Neuroscience ,General Medicine ,medicine.disease ,030104 developmental biology ,Autism ,GABAergic ,Orbitofrontal cortex ,Neuroscience ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Successfully navigating dynamic environments requires balancing the decision to stay at an optimal choice with that to switch to an alternative to acquire new knowledge. However, the genetic factors and cellular activity shaping this “stay or switch” action decision remains largely unidentified. Here we find that mice carrying a deletion of the exchange protein directly activated by cAMP 2 (Epac2) gene, a putative autism locus, exhibit perseverative “stay” behavior in a dynamic foraging task. Anatomical analysis found that the loss of Epac2 resulted in a significant decrease in the density of PV-expressing interneurons in the ventrolateral orbitofrontal cortex (OFC) and dorsal striatum (dSTR). Further, in vitro whole cell patch clamp recordings of PV+ GABAergic interneurons in the dSTR revealed altered neural activity in Epac2 KO mice in response to dopamine. Our findings highlight a potential role of Epac2 in structural changes and neural responses of PV-expressing GABAergic interneurons in the ventrolateral OFC and dSTR during value-based reinforcement learning and link Epac2 function to abnormal decision-making processes and perseverative behaviors seen in autism.
- Published
- 2020
26. Cohen Syndrome Patient iPSC-Derived Neurospheres and Forebrain-Like Glutamatergic Neurons Reveal Reduced Proliferation of Neural Progenitor Cells and Altered Expression of Synapse Genes
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Janghwan Kim, Jung-eun Yang, Hyunhyo Seo, Su-Kyeong Hwang, Hyunjun Ahn, Soo-Kyung Lee, Ji-Hye Kwak, Jin-A Lee, You-Kyung Lee, Chae-Seok Lim, Kyungmin Lee, Bong-Kiun Kaang, Jae-Hyung Lee, and Yong Seok Lee
- Subjects
lcsh:Medicine ,medicine.disease_cause ,Article ,Synapse ,03 medical and health sciences ,Glutamatergic ,0302 clinical medicine ,neurosphere ,Neurosphere ,VPS13B ,medicine ,Induced pluripotent stem cell ,transcriptomic analysis ,030304 developmental biology ,0303 health sciences ,Mutation ,Cohen syndrome ,business.industry ,lcsh:R ,General Medicine ,Neural stem cell ,Cell biology ,Forebrain ,induced pluripotent stem cells (iPSCs) ,business ,030217 neurology & neurosurgery - Abstract
Cohen syndrome (CS), a rare autosomal recessive disorder, has been associated with genetic mutations in the VPS13B gene, which regulates vesicle-mediated protein sorting and transport. However, the cellular mechanism underlying CS pathogenesis in patient-derived human neurons remains unknown. We identified a novel compound heterozygous mutation, due to homozygous variation of biparental origin and heterozygous variation inherited from the father, in the VPS13B gene in a 20-month-old female patient. To understand the cellular pathogenic mechanisms, we generated induced pluripotent stem cells (iPSCs) from the fibroblasts of the CS patient. The iPSCs were differentiated into forebrain-like functional glutamatergic neurons or neurospheres. Functional annotation from transcriptomic analysis using CS iPSC-derived neurons revealed that synapse-related functions were enriched among the upregulated and downregulated genes in the CS neurons, whereas processes associated with neurodevelopment were enriched in the downregulated genes. The developing CS neurospheres were small in size compared to control neurospheres, likely due to the reduced proliferation of SOX2-positive neural stem cells. Moreover, the number of SV2B-positive puncta and spine-like structures was significantly reduced in the CS neurons, suggesting synaptic dysfunction. Taking these findings together, for the first time, we report a potential cellular pathogenic mechanism which reveals the alteration of neurodevelopment-related genes and the dysregulation of synaptic function in the human induced neurons differentiated from iPSCs and neurospheres of a CS patient.
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- 2020
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27. Autophagy pathway upregulation in a human iPSC-derived neuronal model of Cohen syndrome with VPS13B missense mutations
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Bong-Kiun Kaang, You Kyung Lee, Yang Hoon Huh, Chae Seok Lim, Kyungmin Lee, Ji Hye Kwak, Jae-Hyung Lee, Jin-A Lee, Yong Seok Lee, Deok-Jin Jang, Suin Choi, and Soo Kyeong Lee
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Autophagosome ,Autophagosome organization ,Developmental Disabilities ,Induced Pluripotent Stem Cells ,Mutation, Missense ,Vesicular Transport Proteins ,Autophagy-Related Proteins ,Vacuole ,Biology ,lcsh:RC346-429 ,Micro Report ,Fingers ,Gene Knockout Techniques ,Cellular and Molecular Neuroscience ,Downregulation and upregulation ,Intellectual Disability ,VPS13B ,Myopia ,Autophagy ,Humans ,Obesity ,Induced pluripotent stem cell ,Molecular Biology ,lcsh:Neurology. Diseases of the nervous system ,Neurons ,Vacuolar protein sorting ,Cohen syndrome ,iPSC ,Retinal Degeneration ,Autophagosomes ,Fibroblasts ,Axons ,Up-Regulation ,Cell biology ,Cysteine Endopeptidases ,Microscopy, Electron ,Vacuoles ,Microcephaly ,Muscle Hypotonia ,Nerve Net ,HeLa Cells - Abstract
Significant clinical symptoms of Cohen syndrome (CS), a rare autosomal recessive disorder, include intellectual disability, facial dysmorphism, postnatal microcephaly, retinal dystrophy, and intermittent neutropenia. CS has been associated with mutations in the VPS13B (vacuolar protein sorting 13 homolog B) gene, which regulates vesicle-mediated protein sorting and transport; however, the cellular mechanism underlying CS pathogenesis in patient-derived neurons remains uncertain. This report states that autophagic vacuoles accumulate in CS fibroblasts and the axonal terminals of CS patient-specific induced pluripotent stem cells (CS iPSC)-derived neurons; additionally, autophagic flux was significantly increased in CS-derived neurons compared to control neurons. VPS13B knockout HeLa cell lines generated using the CRISPR/Cas9 genome editing system showed significant upregulation of autophagic flux, indicating that VSP13B may be associated with autophagy in CS. Transcriptomic analysis focusing on the autophagy pathway revealed that genes associated with autophagosome organization were dysregulated in CS-derived neurons. ATG4C is a mammalian ATG4 paralog and a crucial regulatory component of the autophagosome biogenesis/recycling pathway. ATG4C was significantly upregulated in CS-derived neurons, indicating that autophagy is upregulated in CS neurons. The autophagy pathway in CS neurons may be associated with the pathophysiology exhibited in the neural network of CS patients.
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- 2020
28. Dysfunction of NMDA receptors in neuronal models of an autism spectrum disorder patient with a DSCAM mutation and in Dscam-knockout mice
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Su Kyeong Hwang, Hyunhyo Seo, Ja Eun Choi, Ariful Islam, Pojeong Park, Kyu Won Shim, Jin-A Lee, You Kyung Lee, Kyungmin Lee, Ji Hye Kwak, Jung eun Yang, Jiah Lee, Ro Un Lee, Yinyi Xiong, Min Jung Kim, Chul Hoon Kim, Bong-Kiun Kaang, Chae Seok Lim, Jae-Hyung Lee, and Yong Seok Lee
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0301 basic medicine ,animal structures ,Dendritic spine ,Autism Spectrum Disorder ,Biology ,medicine.disease_cause ,Receptors, N-Methyl-D-Aspartate ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,DSCAM ,Mice ,0302 clinical medicine ,Downregulation and upregulation ,medicine ,Animals ,Humans ,Induced pluripotent stem cell ,Molecular Biology ,Mice, Knockout ,Neurons ,Gene knockdown ,Mutation ,fungi ,Phenotype ,Psychiatry and Mental health ,030104 developmental biology ,Knockout mouse ,Neuroscience ,Cell Adhesion Molecules ,030217 neurology & neurosurgery - Abstract
Heterogeneity in the etiopathology of autism spectrum disorders (ASD) limits the development of generic remedies, requires individualistic and patient-specific research. Recent progress in human-induced pluripotent stem cell (iPSC) technology provides a novel platform for modeling ASDs for studying complex neuronal phenotypes. In this study, we generated telencephalic induced neuronal (iN) cells from iPSCs derived from an ASD patient with a heterozygous point mutation in the DSCAM gene. The mRNA of DSCAM and the density of DSCAM in dendrites were significantly decreased in ASD compared to control iN cells. RNA sequencing analysis revealed that several synaptic function-related genes including NMDA receptor subunits were downregulated in ASD iN cells. Moreover, NMDA receptor (R)-mediated currents were significantly reduced in ASD compared to control iN cells. Normal NMDA-R-mediated current levels were rescued by expressing wild-type DSCAM in ASD iN cells, and reduced currents were observed by truncated DSCAM expression in control iN cells. shRNA-mediated DSCAM knockdown in control iN cells resulted in the downregulation of an NMDA-R subunit, which was rescued by the overexpression of shRNA-resistant DSCAM. Furthermore, DSCAM was co-localized with NMDA-R components in the dendritic spines of iN cells whereas their co-localizations were significantly reduced in ASD iN cells. Levels of phospho-ERK1/2 were significantly lower in ASD iN cells, suggesting a potential mechanism. A neural stem cell-specific Dscam heterozygous knockout mouse model, showing deficits in social interaction and social memory with reduced NMDA-R currents. These data suggest that DSCAM mutation causes pathological symptoms of ASD by dysregulating NMDA-R function.
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- 2020
29. Loss of the neuronal genome organizer and transcription factor CTCF induces neuronal death and reactive gliosis in the anterior cingulate cortex
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Somi Kim, Chuljung Kwak, Myung Won Kim, Ji-Hye Kwak, Kyungmin Lee, Ja Eun Choi, Nam-Kyung Yu, Ji-il Kim, Dong Il Choi, Hyunhyo Seo, and Bong-Kiun Kaang
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0301 basic medicine ,Male ,Programmed cell death ,CCCTC-Binding Factor ,Receptors, Peptide ,Biology ,Gyrus Cinguli ,Receptors, G-Protein-Coupled ,03 medical and health sciences ,Behavioral Neuroscience ,Mice ,0302 clinical medicine ,Gene expression ,Genetics ,medicine ,Animals ,HSP70 Heat-Shock Proteins ,Gliosis ,Transcription factor ,Anterior cingulate cortex ,Neurons ,Cell Death ,Cell biology ,Chromatin ,Mice, Inbred C57BL ,030104 developmental biology ,medicine.anatomical_structure ,nervous system ,Neurology ,CTCF ,Forebrain ,Female ,medicine.symptom ,Calcium-Calmodulin-Dependent Protein Kinase Type 2 ,Integrin alpha Chains ,030217 neurology & neurosurgery ,Gene Deletion - Abstract
CCCTC-binding factor (CTCF) is a genome organizer that regulates gene expression through transcription and chromatin structure regulation. CTCF also plays an important role during the developmental and adult stages. Cell-specific CTCF deletion studies have shown that a reduction in CTCF expression leads to the development of distinct clinical features and cognitive disorders. Therefore, we knocked out Ctcf (CTCF cKO) in the excitatory neurons of the forebrain in a Camk2a-Cre mouse strain to examine the role of CTCF in cell death and gliosis in the cortex. CTCF cKO mice were viable, but they demonstrated an age-dependent increase in reactive gliosis of astrocytes and microglia in the anterior cingulate cortex (ACC) from 16 weeks of age prior to neuronal loss observed at over 20 weeks of age. Consistent with these data, qRT-PCR analysis of the CTCF cKO ACC revealed changes in the expression of inflammation-related genes (Hspa1a, Prokr2 and Itga8) linked to gliosis and neuronal death. Our results suggest that prolonged Ctcf gene deficiency in excitatory neurons results in neuronal cell death and gliosis, possibly through functional changes in inflammation-related genes.
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- 2020
30. Bozola Flap for Oral Cavity Reconstruction in Patients with Tongue Cancer
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Dongbin Ahn, Jin Ho Sohn, Ji Hye Kwak, and Gil Joon Lee
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medicine.medical_specialty ,business.industry ,Cancer ,030206 dentistry ,Oral cavity ,medicine.disease ,Buccal mucosa ,Surgery ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Otorhinolaryngology ,Tongue ,Medicine ,In patient ,Tongue Neoplasm ,030223 otorhinolaryngology ,business - Published
- 2018
31. Minimizing Temperature Gradient in Photonic Sintering for Defect‐Free High‐Conductivity Cu‐Based Printed Patterns by Bidirectional Irradiation
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Juhee Kim, Seon Hee Seo, Jong Hwan Park, Hee Jin Jeong, Jaewon Lee, Ji Hye Kwak, Geon-Woong Lee, Sooyeon Jeong, Imjeong Ho-Soon Yang, Seung Yol Jeong, Joong Tark Han, and Kang-Jun Baeg
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Temperature gradient ,Materials science ,Mechanics of Materials ,business.industry ,High conductivity ,Mechanical Engineering ,Printed electronics ,Optoelectronics ,Sintering ,Defect free ,Irradiation ,Photonics ,business - Published
- 2021
32. Thermal conductivity of Gd 2 Zr 2 O 7 thin films at various temperatures by using the 3ω method
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Euh Duck Jeong, Hyun-Gyu Kim, Kyong-Soo Hong, Ho-Soon Yang, Ji Hye Kwak, and Jun-Gu Kang
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010302 applied physics ,Superconductivity ,Materials science ,Metals and Alloys ,Analytical chemistry ,02 engineering and technology ,Surfaces and Interfaces ,Substrate (electronics) ,Sputter deposition ,021001 nanoscience & nanotechnology ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Thermal conductivity ,0103 physical sciences ,Thermal ,X-ray crystallography ,Materials Chemistry ,Interfacial thermal resistance ,Thin film ,0210 nano-technology - Abstract
Recently, Gd 2 Zr 2 O 7 has been investigated as a buffer layer of YBa 2 Cu 3 O 7 − x superconductor. Thermal properties of Gd 2 Zr 2 O 7 below room temperature are not well known yet despite of its active studies. For the study of the thermal property at low temperature, the Gd 2 Zr 2 O 7 films with various thicknesses are deposited on the Al 2 O 3 substrate by using the RF magnetron sputtering. Thermal conductivities of Gd 2 Zr 2 O 7 thin films are measured by using the 3 omega method from 80 K to room temperature. We confirm the interfacial thermal resistance and its temperature dependence. The interfacial thermal resistance decreases with increasing temperature unlike the reported temperature dependence of the thermal conductivity. The importance of interfacial effect on the thermal conductivity is being emphasized at very low temperatures.
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- 2017
33. Guided-wavelength-controlled dynamic microwave heating in a near-cutoff waveguide
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Sunshin Jung, Seung Moon Han, and Ji Hye Kwak
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Waveguide (electromagnetism) ,Materials science ,business.industry ,Frequency band ,020209 energy ,Energy Engineering and Power Technology ,Overheating (economics) ,02 engineering and technology ,Dielectric ,Industrial and Manufacturing Engineering ,Wavelength ,Optics ,020401 chemical engineering ,Position (vector) ,0202 electrical engineering, electronic engineering, information engineering ,Cutoff ,0204 chemical engineering ,business ,Microwave - Abstract
Microwave heating due to microwave–matter interactions has been widely used in various materials and processes. However, a key obstacle to the use of microwave heating is the lack of desired control over the location of the antinodes and nodes of microwave fields, resulting in undesirable overheating or non-uniform heating. Here, we report novel dynamic microwave heating based on the guided-wavelength-controlled relocation of the antinodes and nodes using a near-cutoff waveguide, where the frequency-dependent guided wavelength is at least 10 times longer than the free-space wavelength and changes dozens of times larger than in free space. The dynamic microwave heating is demonstrated even in an in-cutoff waveguide since a dielectric sample, to be heated, drives the waveguide out of the cutoff condition. Specifically, the heating position in a sample moves significantly under the manipulation of dynamically rearranged antinodes with only ~ 2% frequency change. Thus, selective microwave heating at a desired part in the sample is realized in a narrow frequency band, subsequently leading to uniform heating by changing the heating position properly.
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- 2021
34. HIF2α/EFEMP1 cascade mediates hypoxic effects on breast cancer stem cell hierarchy
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Jeong-Seok Nam, Na-Hee Lee, Hwa-Yong Lee, Ji-Hye Kwak, and In-Sun Hong
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0301 basic medicine ,Carcinogenesis ,medicine.disease_cause ,Metastasis ,Mice ,0302 clinical medicine ,breast cancer cancer stem cells ,Basic Helix-Loop-Helix Transcription Factors ,RNA, Small Interfering ,Extracellular Matrix Proteins ,education.field_of_study ,biology ,Flow Cytometry ,Cell Hypoxia ,Hyaluronan Receptors ,Oncology ,Gene Knockdown Techniques ,030220 oncology & carcinogenesis ,Neoplastic Stem Cells ,Female ,RNA Interference ,Stem cell ,Research Paper ,Signal Transduction ,Mice, Nude ,Breast Neoplasms ,03 medical and health sciences ,Extracellular matrix protein 1 ,Breast cancer ,Cancer stem cell ,Cell Line, Tumor ,Spheroids, Cellular ,medicine ,Animals ,Humans ,education ,EFEMP1 ,hypoxia ,business.industry ,Gene Expression Profiling ,CD44 ,CD24 Antigen ,medicine.disease ,Xenograft Model Antitumor Assays ,Molecular medicine ,030104 developmental biology ,Immunology ,biology.protein ,Cancer research ,Neoplasm Recurrence, Local ,HIF2α ,business - Abstract
// Ji-Hye Kwak 1, 2, * , Na-Hee Lee 1, 2, * , Hwa-Yong Lee 3, * , In-Sun Hong 1, 2 , Jeong-Seok Nam 4 1 Laboratory of Stem Cell Research, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, 406-840, Republic of Korea 2 Department of Molecular Medicine, School of Medicine, Gachon University, Incheon, 406-840, Republic of Korea 3 The Faculty of Liberal Arts, Jungwon University, Chungbuk, 367-805, Republic of Korea 4 School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, 500-712, Republic of Korea * The authors contributed equally to this work Correspondence to: Jeong-Seok Nam, email: namje@gist.ac.kr In-Sun Hong, email: hongstem@gachon.ac.kr Keywords: breast cancer cancer stem cells, hypoxia, HIF2α, EFEMP1 Received: March 14, 2016 Accepted: May 05, 2016 Published: June 06, 2016 ABSTRACT Breast cancer stem cells (BCSCs) have been shown to contribute to tumor growth, metastasis, and recurrence. They are also markedly resistant to conventional cancer treatments, such as chemotherapy and radiation. Recent studies have suggested that hypoxia is one of the prominent micro-environmental factors that increase the self-renewal ability of BCSCs, partially by enhancing CSC phenotypes. Thus, the identification and development of new therapeutic approaches based on targeting the hypoxia-dependent responses in BCSCs is urgent. Through various in vitro studies, we found that hypoxia specifically up-regulates BCSC sphere formation and a subset of CD44 + /CD24 −/low CSCs. Hypoxia inducible factors 2α (HIF2α) depletion suppressed CSC-like phenotypes and CSC-mediated drug resistance in breast cancer. Furthermore, the stimulatory effects of hypoxia-induced HIF2α on BCSC sphere formation were successfully attenuated by epidermal growth factor-containing fibulin-like extracellular matrix protein 1 (EFEMP1) knockdown. Taken together, these data suggest that HIF2α mediates hypoxia-induced cancer growth/metastasis and that EFEMP1 is a downstream effector of hypoxia-induced HIF2α during breast tumorigenesis.
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- 2016
35. Supercapacitor electrode with an ultrahigh Co3O4 loading for a high areal capacitance
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Yong-Woo Lee, Ji Hye Kwak, and Jin Ho Bang
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Supercapacitor ,Materials science ,Mechanical Engineering ,Areal capacitance ,chemistry.chemical_element ,Condensed Matter Physics ,chemistry ,Mechanics of Materials ,Electrode ,High mass ,General Materials Science ,Composite material ,Mesoporous material ,Carbon ,Electrical conductor ,Cobalt oxide - Abstract
Supercapacitor electrodes heavily loaded with active material suffer from low areal capacitances because close-packed, thick films are often obtained with high mass loading. In this work, nanostructured, mesoporous Co 3 O 4 was directly deposited on a free-standing carbon substrate and evaluated as a supercapacitor electrode. The mesoporous structure combined with a conductive carbon network maximizes the utilization of active material, resulting in a high areal capacitance in spite of the high Co 3 O 4 loading.
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- 2013
36. The operational results of the KSTAR PF cryo-circuit
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Ji-Hye Kwak, Yong Chu, K.M. Moon, N.H. Song, Yong-Sik Chang, H.L. Yang, Yeo-Jin Park, Hyunjung Lee, D.S. Park, J.J. Joo, and S.W. Kwag
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Materials science ,Electromagnet ,Mechanical Engineering ,Nuclear engineering ,Circulator ,chemistry.chemical_element ,Superconducting magnet ,Helium-3 refrigerator ,law.invention ,Pressure head ,Nuclear magnetic resonance ,Nuclear Energy and Engineering ,chemistry ,law ,KSTAR ,Magnet ,General Materials Science ,Helium ,Civil and Structural Engineering - Abstract
The Koreas Superconducting Tokamak Advanced Research (KSTAR) PF cryo-circuit is designed for cooling the fourteen superconducting magnets (Nb3Sn, NbTi) and structures. Those are cooled down by the supercritical helium (4.5 K and 5.5 bar) of a forced flow (pressure gradient: 2 bar) in order to maintain the supercritical state of the helium. To supply a large amount of supercritical helium (>370 g/s), a circulator was inserted into the PF cryo-circuit. The compressed supercritical helium is distributed to five helium manifolds with cryogenic valves and supplied to each PF magnet. While the PF magnets had been operating, the mass flow rate reduced and the pressure head of the circulator was fluctuated depending on the PF magnet operation scenario. These phenomena could damage the circulator and could stop it during operation. Therefore, by-pass valve, which is parallel with in-line valve and is connected with inlet and outlet of the magnet, was opened in order to reduce of the circulator's pressure head. In this paper, we focused on the helium behavior of the superconducting magnet when the by-pass valve was opened in order to release the pressure head of the circulator and the results will be presented.
- Published
- 2013
37. Unusual near-band-edge photoluminescence at room temperature in heavily-doped ZnO:Al thin films prepared by pulsed laser deposition
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Deuk Ho Yeon, Yong Soo Cho, Bhaskar Chandra Mohanty, Kyung Hoon Yoon, Sachindranath Das, and Ji Hye Kwak
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Materials science ,Photoluminescence ,Band gap ,Exciton ,Doping ,Analytical chemistry ,Condensed Matter Physics ,Pulsed laser deposition ,Condensed Matter::Materials Science ,symbols.namesake ,Crystallinity ,Stokes shift ,symbols ,General Materials Science ,Thin film - Abstract
Room temperature photoluminescence (PL) properties of heavily-doped ZnO:Al thin films (with carrier concentration n in the range of 5–20 × 10 20 cm −3 ) prepared by pulsed laser deposition have been investigated. Despite their high carrier concentration, the films exhibited strong room temperature near-band-edge bound excitons at ∼3.34 eV and an unusual peak at ∼3.16 eV, and negligible deep-level emission even for the films deposited at a temperature as low as 25 °C. The radiative efficiency of the films increased with growth temperature as a result of increased n and improved crystallinity. A large blue shift of optical band gap was observed, which is consistent with the n -dependent Burstein–Moss and band gap-renormalization effects. Comparison of the results of the PL and optical measurements revealed a large Stokes shift that increased with increase in n . It has been explained by a model based on local potential fluctuations caused by randomly-distributed doping impurities.
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- 2013
38. Cathodic Stripping Voltammetry of Tellurium(IV) at a Bismuth Film Electrode
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Seungun Choi, Yujin Chae, Noseung Myung, Krishnan Rajeshwar, Wooju Lee, Ji-Hye Kwak, and Sunyoung Ham
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Anodic stripping voltammetry ,chemistry ,Cathodic stripping voltammetry ,Alloy ,Inorganic chemistry ,Electrode ,engineering ,chemistry.chemical_element ,General Chemistry ,engineering.material ,Tellurium ,Stripping (fiber) ,Bismuth - Abstract
during stripping analysis of Te(IV) or Se(IV). Therefore in this study, the conventional HgFE was also deployed to investigate whether alloy formation is a general phenomenon (like in the BiFE instance above) or not. Finally, comparative aspects of Te determination at BiFE and HgFE will be briefly discussed.
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- 2011
39. Co3O4/MnO2Core/Shell-Nanostructured Pseudocapacitor Electrode
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Eun Joo Lee, Ji Hye Kwak, and Jin Ho Bang
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Core shell ,Capacitor ,Nanocomposite ,Materials science ,law ,Electrical resistivity and conductivity ,Electrode ,Pseudocapacitor ,Nanotechnology ,General Chemistry ,Capacitance ,Redox ,law.invention - Abstract
With high powerdensity, specific capacitance, and the use of low-cost elect-rode materials, the pseudocapacitor has been considered anideal system that is capable of bridging the gap between theelectrical double-layer capacitor and the Li-ion battery.However, several issues, such as poor rate capability andcyclability resulting from the low electrical conductivity ofthe active materials, as well as Faradaic redox reactions forcharge storage, must be addressed before practical utilizationis feasible. A great deal of effort has been devoted toaddressing these issues, including nanostructuring activematerials, developing a novel electrode substrate, and syn-thesizing carbon-based nanocomposites.
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- 2014
40. Back-irradiation photonic sintering for defect-free high-conductivity metal patterns on transparent plastic
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Sun-Shin Jung, Su Jin Chun, Ji Hye Kwak, and Chae-Hwa Shon
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Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Delamination ,Sintering ,Nanoparticle ,02 engineering and technology ,Substrate (electronics) ,equipment and supplies ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Selective laser sintering ,Electrical resistivity and conductivity ,law ,Printed electronics ,Optoelectronics ,Photonics ,0210 nano-technology ,business - Abstract
Photonic sintering has attracted considerable attention for printed electronics. It irradiates high-intensity light onto the front surface of metal nanoparticle patterns, which often causes defects such as delamination, cavities, and cracks in the patterns. Here, a back-irradiation photonic sintering method is developed for obtaining defect-free high-conductivity metal patterns on a transparent plastic substrate, through which high-intensity light is irradiated onto the back surface of the patterns for a few milliseconds. Ag patterns back-irradiated with ∼10.0 J cm−2 are defect-free in contrast to front-irradiated patterns and exhibited an electrical conductivity of ∼2.3 × 107 S m−1. Furthermore, real-time high-speed observation reveals that the mechanisms that generate defects in the front-irradiated patterns and prevent defects in the back-irradiated patterns are closely related to vapor trapping. In contrast to the latter, in the former, vapor is trapped and delaminates the patterns from the substrate because the front of the patterns acts as a barrier to vapor venting.
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- 2018
41. Pneumoretroperitoneum, Pneumomediastinum, Subcutaneous Emphysema After a Rectal Endoscopic Mucosal Resection
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Hee Cheul Jung, Sang Su Lee, Hyun Jin Kim, Chang Min Lee, Jin Ju Kim, Ji Hye Kwak, Wan Soo Kim, Jae Min Lee, Jun Hyeong Cho, and Sung Bok Ji
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Subcutaneous emphysema ,medicine.medical_specialty ,Perforation (oil well) ,Pneumomediastinum ,Colonoscopy ,Rectum ,Case Report ,Endoscopic mucosal resection ,03 medical and health sciences ,0302 clinical medicine ,Pneumoperitoneum ,medicine ,Pneumoretroperitoneum ,Perforation ,medicine.diagnostic_test ,business.industry ,Gastroenterology ,Sigmoid colon ,medicine.disease ,digestive system diseases ,Surgery ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,030211 gastroenterology & hepatology ,Radiology ,medicine.symptom ,business - Abstract
An endoscopic mucosal resection (EMR) is an effective and safe therapeutic technique for treating a patient with a laterally-spreading tumor (LST). Colonoscopic-procedure-related complications are noted to be about 2.8% worldwide, and a perforation is the most common. Most colon perforations cause pneumoperitoneum. However, a perforation within the retroperitoneal portion of the colon (rectum and some of sigmoid colon) may cause an extraperitoneal perforation, and the leaking free air may induce pneumoretroperitoneum, pneumomediastinum, and subcutaneous emphysema, depending on the amount of discharged air. Herein, we present the case of a patient with an extraperitoneal colon microperforation which manifested as pneumoretroperitoneum, pneumomediastinum, and subcutaneous emphysema after an EMR for a sigmoid LST, which was successfully treated with medical treatment and endoscopic clipping.
- Published
- 2016
42. Comparative measurement of aortic root by transthoracic echocardiography in normal Korean population based on two different guidelines
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Sung Ji Park, Ji Hye Kwak, Sung A. Chang, Hye Jin Lim, Jin-Oh Choi, Duk Kyung Kim, Jae K. Oh, Myoung Kyun Son, Seung Woo Park, and Sang-Chol Lee
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Adult ,Male ,medicine.medical_specialty ,Transthoracic echocardiography ,Diastole ,Sensitivity and Specificity ,Reference Values ,Internal medicine ,medicine.artery ,Ascending aorta ,Republic of Korea ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Cardiac skeleton ,Systole ,Aorta ,Angiology ,Aged ,Cardiac cycle ,business.industry ,Sinotubular Junction ,Research ,Reproducibility of Results ,General Medicine ,Middle Aged ,Healthy Volunteers ,Radiology Nuclear Medicine and imaging ,Echocardiography ,Practice Guidelines as Topic ,Cardiology ,cardiovascular system ,Aortic root measurement ,Normal reference ,Female ,Guideline Adherence ,Cardiology and Cardiovascular Medicine ,business - Abstract
Background Aortic root size is an important parameter in vascular diseases and can be easily assessed by transthoracic echocardiography. However, measurements values may vary according to cardiac cycle and the definition used for edge. This study aimed to define normal values according to the measurement method specified by two different guidelines to determine the influence of the different methods on echocardiographic measurements. Methods Healthy Korean adults were enrolled. The aortic root diameters were measured twice at four levels (aortic annulus, sinuses of Valsalva, sinotubular junction, and ascending aorta) by the 2005 American Society of Echocardiography (ASE) guidelines (measured from leading edge to leading edge during diastole) and the 2010 ASE pediatric guidelines (measured from inner edge to inner edge during systole). Results One hundred twelve subjects aged 20–69 years were enrolled. The aortic diameters (cm) determine by the aforementioned two guidelines showed significant difference. Measurements were larger in 2005 ASE guideline at aortic annuls, sinuses of Valsalva, and sinotubular junction level, but smaller at ascending aortic level with 2-3mm of differences. Intraobserver variability was similarly good, but interobserver variability was slightly higher than intraobserver variability in both measurement methods. BSA and age was most important determinant for aortic root size. Conclusions The measurement method of aortic root can affect the echocardiographic result. The measurement method should be noted when assessing clinical significance of aortic root measurement.
- Published
- 2013
43. Involvement of cAMP-guanine nucleotide exchange factor II in hippocampal long-term depression and behavioral flexibility.
- Author
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Kyungmin Lee, Yuki Kobayashi, Hyunhyo Seo, Ji-Hye Kwak, Akira Masuda, Chae-Seok Lim, Hye-Ryeon Lee, SukJae Joshua Kang, Pojeong Park, Su-Eon Sim, Naomi Kogo, Hiroaki Kawasaki, Bong-Kiun Kaang, and Shigeyoshi Itohara
- Subjects
GUANINE nucleotide exchange factors ,NUCLEOTIDE exchange factors ,PROTEIN kinases ,HIPPOCAMPUS (Brain) ,SYNAPSES - Abstract
Background: Guanine nucleotide exchange factors (GEFs) activate small GTPases that are involved in several cellular functions. cAMP-guanine nucleotide exchange factor II (cAMP-GEF II) acts as a target for cAMP independently of protein kinase A (PKA) and functions as a GEF for Rap1 and Rap2. Although cAMP-GEF II is expressed abundantly in several brain areas including the cortex, striatum, and hippocampus, its specific function and possible role in hippocampal synaptic plasticity and cognitive processes remain elusive. Here, we investigated how cAMP-GEF II affects synaptic function and animal behavior using cAMP-GEF II knockout mice. Results: We found that deletion of cAMP-GEF II induced moderate decrease in long-term potentiation, although this decrease was not statistically significant. On the other hand, it produced a significant and clear impairment in NMDA receptor-dependent long-term depression at the Schaffer collateral-CA1 synapses of hippocampus, while microscopic morphology, basal synaptic transmission, and depotentiation were normal. Behavioral testing using the Morris water maze and automated IntelliCage system showed that cAMP-GEF II deficient mice had moderately reduced behavioral flexibility in spatial learning and memory. Conclusions: We concluded that cAMP-GEF II plays a key role in hippocampal functions including behavioral flexibility in reversal learning and in mechanisms underlying induction of long-term depression. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
44. Comparative measurement of aortic root by transthoracic echocardiography in normal Korean population based on two different guidelines.
- Author
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Myoung Kyun Son, Sung-A Chang, Ji Hye Kwak, Hye Jin Lim, Sung-Ji Park, Jin-Oh Choi, Sang-Chol Lee, Seung Woo Park, Duk-Kyung Kim, and Jae K Oh
- Subjects
AORTA ,ECHOCARDIOGRAPHY ,KOREANS ,VASCULAR diseases ,VALSALVA'S maneuver ,HEALTH - Abstract
Background: Aortic root size is an important parameter in vascular diseases and can be easily assessed by transthoracic echocardiography. However, measurements values may vary according to cardiac cycle and the definition used for edge. This study aimed to define normal values according to the measurement method specified by two different guidelines to determine the influence of the different methods on echocardiographic measurements. Methods: Healthy Korean adults were enrolled. The aortic root diameters were measured twice at four levels (aortic annulus, sinuses of Valsalva, sinotubular junction, and ascending aorta) by the 2005 American Society of Echocardiography (ASE) guidelines (measured from leading edge to leading edge during diastole) and the 2010 ASE pediatric guidelines (measured from inner edge to inner edge during systole). Results: One hundred twelve subjects aged 20-69 years were enrolled. The aortic diameters (cm) determine by the aforementioned two guidelines showed significant difference. Measurements were larger in 2005 ASE guideline at aortic annuls, sinuses of Valsalva, and sinotubular junction level, but smaller at ascending aortic level with 2-3mm of differences. Intraobserver variability was similarly good, but interobserver variability was slightly higher than intraobserver variability in both measurement methods. BSA and age was most important determinant for aortic root size. Conclusions: The measurement method of aortic root can affect the echocardiographic result. The measurement method should be noted when assessing clinical significance of aortic root measurement. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
45. Co3O4/MnO2 Core/Shell-Nanostructured Pseudocapacitor Electrode.
- Author
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Ji Hye Kwak, Eun Joo Lee, and Jin Ho Bang
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NANOSTRUCTURED materials , *ELECTRODES , *CAPACITORS , *COBALT , *OXIDES - Abstract
This article presents a study on nanostructured pseudocapacitor electrodes. It discusses issues to be addressed in the use of pseudocapacitors as next-general energy storage systems, the design of the nanostructure, the morphology of the deposited cobalt (II,III) oxide, and the use of cyclic voltammetry measurement to examine the electrochemical behavior of the electrodes.
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- 2014
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46. Involvement of cAMP-guanine nucleotide exchange factor II in hippocampal long-term depression and behavioral flexibility
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Pojeong Park, Hiroaki Kawasaki, Hyunhyo Seo, Shigeyoshi Itohara, Naomi Kogo, Su-Eon Sim, Akira Masuda, Hye-Ryeon Lee, Bong-Kiun Kaang, Yuki Kobayashi, Ji-Hye Kwak, Chae-Seok Lim, Kyungmin Lee, and Sukjae Joshua Kang
- Subjects
animal structures ,Long-Term Potentiation ,GTPase ,Hippocampal formation ,environment and public health ,Hippocampus ,Receptors, N-Methyl-D-Aspartate ,Synaptic plasticity ,Nucleotide exchange factor ,Cellular and Molecular Neuroscience ,Spatial memory ,Reversal learning ,Animals ,Guanine Nucleotide Exchange Factors ,Learning ,Long-term depression ,Molecular Biology ,Mice, Knockout ,Electroshock ,Behavior, Animal ,Research ,fungi ,Brain ,Long-term potentiation ,Mice, Inbred C57BL ,enzymes and coenzymes (carbohydrates) ,Synapses ,Rap1 ,Guanine nucleotide exchange factor ,biological phenomena, cell phenomena, and immunity ,Psychology ,Neuroscience ,Knockout mice - Abstract
Background Guanine nucleotide exchange factors (GEFs) activate small GTPases that are involved in several cellular functions. cAMP-guanine nucleotide exchange factor II (cAMP-GEF II) acts as a target for cAMP independently of protein kinase A (PKA) and functions as a GEF for Rap1 and Rap2. Although cAMP-GEF II is expressed abundantly in several brain areas including the cortex, striatum, and hippocampus, its specific function and possible role in hippocampal synaptic plasticity and cognitive processes remain elusive. Here, we investigated how cAMP-GEF II affects synaptic function and animal behavior using cAMP-GEF II knockout mice. Results We found that deletion of cAMP-GEF II induced moderate decrease in long-term potentiation, although this decrease was not statistically significant. On the other hand, it produced a significant and clear impairment in NMDA receptor-dependent long-term depression at the Schaffer collateral-CA1 synapses of hippocampus, while microscopic morphology, basal synaptic transmission, and depotentiation were normal. Behavioral testing using the Morris water maze and automated IntelliCage system showed that cAMP-GEF II deficient mice had moderately reduced behavioral flexibility in spatial learning and memory. Conclusions We concluded that cAMP-GEF II plays a key role in hippocampal functions including behavioral flexibility in reversal learning and in mechanisms underlying induction of long-term depression.
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47. Autophagy activity contributes to the impairment of social recognition in Epac2 −/− mice
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Ji-Hye Kwak, You-kyung Lee, Mi-Hee Jun, Mootaek Roh, Hyunhyo Seo, Juhyun Lee, Kyungmin Lee, and Jin-A Lee
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Autophagy ,Epac2 ,Social recognition ,Neurodevelopmental disorders ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract Autophagy is a lysosomal degradation pathway that regulates cellular homeostasis. It is constitutively active in neurons and controls the essential steps of neuronal development, leading to its dysfunction in neurodevelopmental disorders. Although mTOR-associated impaired autophagy has previously been reported in neurodevelopmental disorders, there is lack of information about the dysregulation of mTOR-independent autophagy in neurodevelopmental disorders. In this study, we investigated whether the loss of Epac2, involved in the mTOR-independent pathway, affects autophagy activity and whether the activity of autophagy is associated with social–behavioral phenotypes in mice with Epac2 deficiencies. We observed an accumulation of autophagosomes and a significant increase in autophagic flux in Epac2-deficient neurons, which had no effect on mTOR activity. Next, we examined whether an increase in autophagic activity contributed to the social behavior exhibited in Epac2 −/− mice. The social recognition deficit observed in Epac2 −/− mice recovered in double transgenic Epac2 −/− : Atg5 +/− mice. Our study suggests that excessive autophagy due to Epac2 deficiencies may contribute to social recognition defects through an mTOR-independent pathway.
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- 2021
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48. Autophagy pathway upregulation in a human iPSC-derived neuronal model of Cohen syndrome with VPS13B missense mutations
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You-Kyung Lee, Soo-Kyeong Lee, Suin Choi, Yang Hoon Huh, Ji-Hye Kwak, Yong-Seok Lee, Deok-Jin Jang, Jae-Hyung Lee, Kyungmin Lee, Bong-Kiun Kaang, Chae-Seok Lim, and Jin-A Lee
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Cohen syndrome ,Autophagy ,VPS13B ,iPSC ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract Significant clinical symptoms of Cohen syndrome (CS), a rare autosomal recessive disorder, include intellectual disability, facial dysmorphism, postnatal microcephaly, retinal dystrophy, and intermittent neutropenia. CS has been associated with mutations in the VPS13B (vacuolar protein sorting 13 homolog B) gene, which regulates vesicle-mediated protein sorting and transport; however, the cellular mechanism underlying CS pathogenesis in patient-derived neurons remains uncertain. This report states that autophagic vacuoles accumulate in CS fibroblasts and the axonal terminals of CS patient-specific induced pluripotent stem cells (CS iPSC)-derived neurons; additionally, autophagic flux was significantly increased in CS-derived neurons compared to control neurons. VPS13B knockout HeLa cell lines generated using the CRISPR/Cas9 genome editing system showed significant upregulation of autophagic flux, indicating that VSP13B may be associated with autophagy in CS. Transcriptomic analysis focusing on the autophagy pathway revealed that genes associated with autophagosome organization were dysregulated in CS-derived neurons. ATG4C is a mammalian ATG4 paralog and a crucial regulatory component of the autophagosome biogenesis/recycling pathway. ATG4C was significantly upregulated in CS-derived neurons, indicating that autophagy is upregulated in CS neurons. The autophagy pathway in CS neurons may be associated with the pathophysiology exhibited in the neural network of CS patients.
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- 2020
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49. Nonviolent Resistance
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Ji-hye, Kwak, director
- Published
- 2012
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