249 results on '"Kim, Tae Hoon"'
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2. Effects of antiarrhythmic drug responsiveness and diagnosis‐to‐ablation time on outcomes after catheter ablation for persistent atrial fibrillation
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Kim, Hong‐Ju, Kim, Daehoon, Kim, Kipoong, Choi, Sung Hwa, Kim, Moon‐Hyun, Park, Je‐Wook, Yu, Hee Tae, Kim, Tae‐Hoon, Uhm, Jae‐Sun, Joung, Boyoung, Lee, Moon‐Hyoung, and Pak, Hui‐Nam
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The impact of delaying atrial fibrillation catheter ablation (AFCA) for antiarrhythmic drug (AAD) management on the disease course remains unclear. This study investigated AFCA rhythm outcomes based on the diagnosis‐to‐ablation time (DAT) and AAD responsiveness in participants with persistent AF (PeAF). We included data from 1038 AAD‐resistant PeAF participants, all of whom had a clear time point for AF diagnosis, especially PeAF at diagnosis time, and had undergone an AFCA for the first time. Participants who experienced recurrences of paroxysmal type on AAD therapy were analyzed as a cohort of AAD‐partial responders; those maintaining PeAF on AAD were AAD‐non‐responders. We determined the DAT cutoff for best discriminating long‐term rhythm outcomes using a maximum log‐likelihood estimation method based on the Cox proportional hazard regression model. Of the participants (79.8% male; median age 61), 806 (77.6%) were AAD‐non‐responders. AAD‐non‐responders had a higher body mass index and a larger left atrial diameter than AAD‐partial‐responders. They also had a higher incidence of AF recurrence after AFCA (adjusted hazard ratio 1.75, 95% confidence interval 1.33–2.30; log‐rank p< .001) compared to AAD‐partial‐responders. The maximum log‐likelihood estimation showed bimodal cutoffs at 22 and 40 months. The optimal DAT cutoff rhythm outcome was 22 months, which discriminated better in the AAD‐partial‐responders than in the AAD‐non‐responders. Both DAT and AAD responsiveness influenced AFCA rhythm outcomes. Delaying AFCA to a DAT of longer than 22 months was inadvisable, particularly in the participants in whom PeAF was changed to paroxysmal AF during AAD therapy. AAD‐non‐responders had a higher incidence of AF recurrence after AFCA compared to AAD‐partial‐responders. The maximum log‐likelihood estimation showed bimodal cutoffs at 22 and 40 months. The optimal DAT cutoff rhythm outcome was 22 months, which discriminated better in the AAD‐partial‐responders than in the AAD‐non‐responders.
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- 2024
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3. Optimizing the Synergistic Effect of Co and Fe for Efficient and Durable Oxygen Evolution under Alkaline Conditions
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Han, Sanghwi, Kim, Sungjun, Kim, Tae Hoon, Lee, Jang Yong, and Yoon, Jeyong
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Developing robust oxygen evolution reaction (OER) electrocatalysts is crucial for advancing anion exchange membrane water electrolysis (AEMWE). In this study, we present a catalyst optimizing the synergistic effect of Co and Fe by creating a CoFe-based layer on a Fe-based electrode (Fe@CoFe). The Fe@CoFe exhibits an overpotential of 168 mV at 10 mA cm–2under half-cell conditions and a current density of 10 A cm–2at 2 V in the AEMWE system with 1 M KOH. Moreover, it showcases a degradation rate of 76 μV h–1for 2000 h at 500 mA cm–2in the single-cell system. This study demonstrates the feasibility of achieving efficient and durable water electrolysis using a transition metal-based catalyst exclusively fabricated via electrodeposition.
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- 2024
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4. Clinical and pathophysiologic determinants of catheter ablation outcome in hypertrophic cardiomyopathy with atrial fibrillation
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Lee, Jae‐Hyuk, Cho, Iksung, Choi, Sung Hwa, Yu, Hee Tae, Kim, Tae‐Hoon, Uhm, Jae‐Sun, Joung, Boyoung, Lee, Moon‐Hyoung, Hong, Geu‐Ru, Hwang, Chun, and Pak, Hui‐Nam
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Hypertrophic cardiomyopathy (HCM) is frequently associated with atrial fibrillation (AF). We compared clinical, echocardiographic, and electrophysiological parameters between HCM subtypes and those without HCM at AF catheter ablation (AFCA) and analyzed post‐AFCA reverse remodeling and AF recurrence based on HCM presence and subtype. Among 5161 consecutive patients who underwent de novo AFCA, we included HCM patients and control patients who were age‐, gender‐, and AF type‐matched. Between AF‐HCM patients and controls, we compared baseline values for left atrium (LA) wall thickness (LAWT), reverse remodeling at 1‐year follow‐up, and procedural outcomes over the course of follow‐up between two groups. A total of 122 AF‐HCM patients and 318 control patients were included. AF‐HCM patients had more frequent heart failure and higher LA diameter, E/Em, and LA pressure (all, p< .001). However, LAWT did not differ from control group. A year after AFCA, degree of LA reverse remodeling was significantly lower in AF‐HCM than in control group (ΔLA dimension, p= .025). Nonapical HCM (HR 1.71; 95% CI 1.05–2.80), persistent AF (HR 1.46; 95% CI 1.05–2.04), and LA dimension (HR 1.04; 95% CI 1.01–1.06) were independent risk factors for AF recurrence. During 78.0 months of follow‐up, nonapical HCM patients showed higher AF recurrence rate than both apical HCM (log‐rank p= .005) and control patients (log‐rank p= .002). The presence of HCM, particularly nonapical HCM, displayed increased LA hemodynamic loading with diastolic dysfunction and had poorer rhythm outcomes after AFCA compared to both apical HCM and control group. Comparison of LA hemodynamic and structural parameters between AF‐HCM and control groups and the difference of LA reservoir strain according to the type of HCM with rhythm outcome after AFCA in three groups.
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- 2024
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5. Optimizing compounding ratios of polycarbonate and recycled polyethylene terephthalate for electronic device covers: a study on sustainable materials
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Kim, Young Wan, Janani, Gnanaprakasam, Kim, Joon Young, Moon, Dae Jun, Kim, Tae-Hoon, Lee, Hyunjung, and Sim, Uk
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Plastic pollution poses a serious risk globally and is having a major adverse impact on nearly every marine and freshwater ecosystem on the planet. The plastic trash collected from the marine environment, can harm marine ecosystems and humans. While there are several challenges to manufacture products from recycled marine plastics, including a high price and consumer demand for high-quality recycled materials, efforts, and research to recycle marine plastics are critical. One promising application of recycled marine plastics is blending recycled polyethylene terephthalate (re-PET) with other polymers, such as polycarbonate (PC), to reproduce desired physical properties in composites. In this study, we investigated the optimal ratio of PC and ocean-bound plastic (OBP), recycled PET (re-PET) as a composite material suitable for sustainable electronic device covers, and analyzed its physicochemical properties. The results showed that PC/re-PET5 composites containing 5% re-PET recycled from OBP had the most suitable properties for electronic device covers. Developing composite materials using recycled plastics represents a promising stride towards advancing the principles of a circular economy and fostering sustainable product design.
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- 2024
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6. Association of extra‐pulmonary vein triggers with low‐voltage area and clinical recurrence in patients with atrial fibrillation undergoing catheter ablation
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Park, In Jae, Kim, Daehoon, Yu, Hee Tae, Kim, Tae‐Hoon, Uhm, Jae‐Sun, Joung, Boyoung, Lee, Moon‐Hyoung, Hwang, Chun, and Pak, Hui‐Nam
- Abstract
Although extra‐pulmonary vein (PV) triggers (ExPVTs) play a role in atrial fibrillation (AF) recurrence after catheter ablation (AFCA), the mechanism is unknown. We explored whether the locations of ExPVTs were associated with low‐voltage scar areas (LVAs). Among 2255 consecutive patients who underwent a de novo AFCA, 1696 (male 72.1%, median 60 years old, paroxysmal 64.7%) were included who underwent isoproterenol provocation and voltage mapping of the left atrium (LA) during their procedures. We investigated the associations between ExPVTs and their mean LA voltage and colocalization of ExPVTs within LVAs (<0.2 mV). We observed ExPVTs in 181 (10.7%) patients (60 in the LA, 99 in the right atrium [RA], 16 biatrial, and 6 unmappable). A lower mean LA voltage was independently associated with the existence of ExPVTs (OR 0.77 per 1 SD mV increase, 95% CI 0.60–0.99, p= .039). Among 76 patients who had ExPVTs[LA], 43 (56.6%) had ExPVTs within LVAs. During a median of a 42‐month follow‐up, patients with ExPVTs had a higher AF recurrence than those without (HR 1.87, 95% CI 1.48–2.37, Log‐rank p< .001), but colocalization of ExPVTs and LVAs (Log‐rank p= .544) and the anatomical location of ExPVTs (Log‐rank p= .084) did not affect the rhythm outcome. The presence of ExPVTs was associated with low LA voltage and poor rhythm outcome post‐AFCA, but the colocalization of ExPVTs and LVA in LA did not affect rhythm outcome. The presence of an ExPVT was associated with a low LA voltage and poor rhythm outcome after AFCA, but the electroanatomical location of the ExPVT was not.
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- 2024
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7. Using computed tomogram atrial myocardial thickness maps in high‐power short‐duration radiofrequency pulmonary vein isolation: UTMOST AF
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Hwang, Taehyun, Kwon, Oh‐Seok, Yu, Hee Tae, Yang, Song‐Yi, Kim, Daehoon, Kim, Tae‐Hoon, Uhm, Jae‐Sun, Joung, Boyoung, Lee, Moon‐Hyoung, Hwang, Chun, and Pak, Hui‐Nam
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High‐power short‐duration (HPSD) ablation creates wide, shallow lesions using radiofrequency (RF) heating. It is uncertain if adjusting RF energy based on atrial wall thickness provides extra benefits. We studied the safety and effectiveness of tailored HPSD energy based on left atrial (LA) wall thickness (LAWT) for circumferential pulmonary vein isolation (CPVI) in patients with paroxysmal atrial fibrillation (PAF). We enrolled 212 patients (68.4% male, mean age: 59.5 ± 11.0 years) and randomly assigned them to two groups: LAWT‐guided CPVI (WT, n= 108) and conventional CPVI (control, n= 104). Both groups used an open irrigated‐tip deflectable catheter to apply 50 W for 10 s to the posterior LA, while controls used 60 W for 15 s on other LA regions. RF delivery time in WT was titrated (15 s at LAWT > 2.1 mm, 13 s at 1.4–2.1 mm, and 11 s at <1.4 mm) according to the computed tomogram‐myocardial thickness color map. After a mean follow‐up of 13.4 ± 7.0 months, the WT and control groups showed no significant difference regarding clinical recurrence rate (13.9% vs. 5.8%, respectively; p= .061) and major complication rate (4.6% vs. 3.8%, respectively; p> .999). The total procedure time, cardioversion rate, and post‐procedural AAD prescription rates did not significantly differ between the groups. The LAWT‐guided energy titration strategy did not result in improved procedural safety and efficacy compared to the conventional 50–60 W‐HPSD CPVI in patients with PAF. Overview of the methods and results of our study. The clinical recurrence rate between WT‐guided ablation and control groups did not significantly differ.
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- 2024
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8. Adaptive vessel tracing and segmentation in OCT enables robust quantification of blood vessel wall-to-lumen ratio in the retina
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Hammer, Daniel X., Bizheva, Kostadinka, Schuele, Georg, Adejumo, Tobiloba, Ma, Guangying, Son, Taeyoon, Kim, Tae-Hoon, Le, David, Dadzie, Albert K., Ahmed, Shaiban, and Yao, Xincheng
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- 2024
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9. Head-Up Haptic Display Using Dual-Mode Haptic Actuator for Vehicles
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Heo, Yong Hae, Kim, Tae-Hoon, Choi, Dong-Soo, and Kim, Sang-Youn
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Driving assistance modules are important components to improving driver safety in driving environments, which can create overloaded multisensory information. This article introduces the concept of a head-up haptic display that assists drivers in keeping their visual attention focused, and then offers a haptic actuator that may be used as the main component in the head-up haptic display. We selected magneto-rheological elastomer (MRE) as the base material and adopted a porous structure to reduce its initial stiffness. Furthermore, we fabricate a haptic actuator based on an MRE having a porous structure (pMRE) and a solenoid. The current to the solenoid generates a magnetic field that causes the pMRE to stiffen, thereby increasing the resistive force. As soon as the current input is removed, the pMRE becomes soft again. We simulated the solenoid coil and the magnetic path to further maximize the magneto-motive force generated by the solenoid coil and experimentally optimized the pMRE. We showed that the proposed haptic actuator creates not only a sufficient resistive force but also vibration to generate various haptic sensations. Moreover, we constructed a head-up haptic display using four haptic actuators and demonstrated the possibility of utilizing a new user interface to increase driving safety.
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- 2024
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10. Analysis of age-related prevalence and risk factors of chronic rhinosinusitis with asthma
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Tai, Junhu, Jeong, Yujin, Lee, Kijeong, Park, Jaehyung, Han, Munsoo, and Kim, Tae Hoon
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Objective To determine age-related risk factors for chronic rhinosinusitis (CRS) with asthma.Methods Data were obtained from a national survey of non-hospitalized civilians conducted by the Korean Center for Disease Control and Prevention. CRS diagnosis was based on the guidelines of the European Position Paper on Rhinosinusitis and Nasal Polyps 2020. Asthma was judged based on whether the patient had been diagnosed with asthma in the past. Of the 45,811 survey participants, 26,335 were included in the cross-sectional study. Participants included in the study were divided into the control, CRS, and CRS with asthma groups. Age-related risk factors were analyzed in patients aged < 60 or > 60 years. Univariate logistic analyses were performed to evaluate the relationship between groups. Risk factors included age, sex, household income, residence, education level, occupation, and body mass index (BMI).Results Education level (Odds Ratio [OR]: 0.342, P = .0003), BMI (OR: 1.09, P = .0082), and total IgE (TIgE) levels (OR: 5.582, P = .003) were significantly different between the control and the CRS with asthma group. Education level (OR: 0.478, P = .0016) and TIgE levels (OR: 4, P = .0218) were significantly different between the CRS and CRS with asthma groups under 60 years of age. BMI (OR: 1.087, P = .0443; OR: 1.104, P = .0224) showed a significant difference between all three groups with age > 60 years.Conclusion Progression to CRS with asthma is influenced by education level, occupation, and TIgE levels in patients under 60 years of age. BMI was the only influencing factor associated with the progression to CRS with asthma in those aged > 60 years.
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- 2024
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11. A conformal titanyl phosphate amorphous overlayer for enhancing photoelectrochemical hydrogen peroxide production
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Kim, Jaekyum, Kim, Young Eun, Je, Minyeong, Hong, Won Tae, Lee, Chang-Lyoul, Kim, Tae-Hoon, Cho, Sung Min, Choi, Chang Hyuck, Choi, Heechae, Choe, Woo-Seok, and Kim, Jung Kyu
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Amorphous titanyl phosphate (a-TP) overlaid on TiO2is strategically designed to actively promote H2O2production via water oxidation reaction (WOR). Beyond conformally covered amorphous overlayer, a-TP/TiO2exhibited enhanced H2O2production and Faraday efficiency.
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- 2023
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12. Ambient-Stable n-Type Carbon Nanotube/Organic Small-Molecule Thermoelectrics Enabled by Energy Level Control
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Kim, Tae-hoon, Jang, Jae Gyu, Kim, Sung Hyun, and Hong, Jong-In
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The stability of n-type organic and hybrid thermoelectric materials is limited in terms of their practical application to p–n parallel thermoelectric devices. We demonstrate the ambient stability of an n-type single-walled carbon nanotube/organic small-molecule (SWNT/OSM) hybrid by deepening the lowest occupied molecular orbital energy level. This hybrid exhibited the best figure of merit (0.032) among n-type SWNT/OSM hybrid thermoelectrics and an enhanced power factor of 291.0 μW m–1K–2. Furthermore, we observed that the n-type thermoelectric stability of a hybrid of SWNT and pipcontaining two N-ethylpiperidinyl groups on both sides of a naphthalenediimide core was retained at 87% over 7 months (220 days) under ambient conditions without encapsulation.
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- 2023
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13. Development of a polystyrene phantom for quality assurance of a Gamma Knife®
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Choi, Yona, Chun, Kook Jin, Bahng, Jungbae, Choi, Sang Hyoun, Cho, Gyu Seok, Kim, Tae Hoon, Yang, Hye Jeong, Seo, Yeong Chan, and Chung, Hyun-Tai
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A polystyrene phantom was developed following the guidance of the International Atomic Energy Association (IAEA) for gamma knife (GK) quality assurance. Its performance was assessed by measuring the absorbed dose rate to water and dose distributions. The phantom was made of polystyrene, which has an electron density (1.0156) similar to that of water. The phantom included one outer phantom and four inner phantoms. Two inner phantoms held PTW T31010 and Exradin A16 ion chambers. One inner phantom held a film in the XY plane of the Leksell coordinate system, and another inner phantom held a film in the YZ or ZX planes. The absorbed dose rate to water and beam profiles of the machine-specific reference (msr) field, namely, the 16 mm collimator field of a GK Perfexion™ or Icon™, were measured at seven GK sites. The measured results were compared to those of an IAEA-recommended solid water (SW) phantom. The radius of the polystyrene phantom was determined to be 7.88 cm by converting the electron density of the plastic, considering a water depth of 8 g/cm2. The absorbed dose rates to water measured in both phantoms differed from the treatment planning program by less than 1.1%. Before msr correction, the PTW T31010 dose rates (PTW Freiberg GmbH, New York, NY, USA) in the polystyrene phantom were 0.70 (0.29)% higher on average than those in the SW phantom. The Exradin A16 (Standard Imaging, Middleton, WI, USA) dose rates were 0.76 (0.32)% higher in the polystyrene phantom. After msr correction factors were applied, there were no statistically significant differences in the A16 dose rates measured in the two phantoms; however, the T31010 dose rates were 0.72 (0.29)% higher in the polystyrene phantom. When the full widths at half maximum and penumbras of the msr field were compared, no significant differences between the two phantoms were observed, except for the penumbra in the Y-axis. However, the difference in the penumbra was smaller than variations among different sites. A polystyrene phantom developed for gamma knife dosimetry showed dosimetric performance comparable to that of a commercial SW phantom. In addition to its cost effectiveness, the polystyrene phantom removes air space around the detector. Additional simulations of the msr correction factors of the polystyrene phantom should be performed.
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- 2023
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14. Relationship Between Hallux Valgus Recurrence and Sesamoid Position on Anteroposterior Standing Radiographs After Distal Chevron Metatarsal Osteotomy
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Kim, Tae-Hoon, Choi, Young-Rak, Lee, Ho-Seong, Bak, Gyeong-Gu, and Moon, Sung-Ho
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Background: Recurrence of the hallux valgus deformity has various causes, and the incomplete reduction of sesamoids may be one of the important issues. However, we have seen several patients with postoperative lateral sesamoid displacement on anteroposterior (AP) standing radiographs who did not experience hallux valgus recurrence. Therefore, we hypothesized that lateral displacement of the sesamoid on AP standing radiographs does not cause hallux valgus recurrence.Methods: The study included 269 feet (185 patients) with hallux valgus treated with distal chevron metatarsal osteotomy. Mean patient age was 64.26 (range, 15-80) years. Patients were followed up for an average of 33.85 (range, 12-228) months between April 2002 and December 2019. The patients were divided into 4 groups, according to the presence or absence of hallux valgus recurrence and sesamoid reduction.Results: During outpatient follow-up, we discovered 99 feet (42.1%) in which hallux valgus did not recur despite lateral sesamoid displacement (grade IV-VII) on AP standing radiographs. Hallux valgus angle (HVA, 2.7 to 7.9 degrees), intermetatarsal angle (IMA, 4.6 to 6.2 degrees), and sesamoid grades (2.1 to 3.5) all deteriorated over time after surgery, and each indicator was statistically significantly altered, and changes in the 3 indicators had a statistically significant positive correlation. Changes in HVA and IMA between feet with and without sesamoid reduction on AP standing radiographs increased over time, with the differences in HVA (2.9 degrees) and IMA (0.9 degrees) being significant at final follow-up (P< .05 for each). Regardless of whether sesamoid reduction was achieved on AP standing radiographs, the final analysis showed that HVA and IMA in both groups worsened over time. Further, there were no differences between the 2 groups in the patterns of change over time.Conclusion: In our cohort, postoperative sesamoid position on AP standing radiographs was not associated with hallux valgus recurrence based on radiographic criteria.Level of Evidence: Level III, retrospective comparative study.
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- 2023
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15. Sex difference in atrial fibrillation recurrence after catheter ablation and antiarrhythmic drugs
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Park, Yoon Jung, Park, Je-Wook, Yu, Hee Tae, Kim, Tae-Hoon, Uhm, Jae-Sun, Joung, Boyoung, Lee, Moon-Hyoung, and Pak, Hui-Nam
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ObjectiveThe risk of recurrence after atrial fibrillation (AF) catheter ablation (AFCA) is higher in women than in men. However, it is unknown whether a sex difference exists in antiarrhythmic drug (AAD) responsiveness among patients with recurrence.MethodsAmong 2999 consecutive patients (26.5% women, 58.3±10.9 years old, 68.1% paroxysmal AF) who underwent de novo AFCA, we compared and evaluated the sex differences in rhythm outcome in 1094 patients with recurrence and in 788 patients who subsequently underwent rhythm control with AAD.ResultsDuring a follow-up of 48.2±34.9 months, 1094 patients (36.5%) had AF recurrence after AFCA, and 508 of 788 patients (64.5%) had AF recurrence under AAD. Although the rhythm outcome of a de novo AFCA was worse (log-rank p=0.041, HR 1.28, 95% CI 1.02 to 1.59), p=0.031) in women, AAD response after postprocedural recurrences was better in women than in men (log-rank p=0.003, HR 0.75, 95% CI 0.59 to 0.95, p=0.022), especially in women older than 60 years old (log-rank p=0.003). In 249 patients who underwent repeat procedure after AAD use, the pulmonary vein (PV) reconnection rate (62.7% vs 76.8%, p=0.048) was lower in women than in men but not the existence of extra-PV trigger (37.8% vs 25.4%, p=0.169).ConclusionsAlthough women showed worse rhythm outcomes than men after AFCA, the post-AFCA AAD response was better in elderly women than in men.Trial registration numberNCT02138695.
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- 2023
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16. Recent research trends in perfluoropolyether for energy device applications: a mini review
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Shanmugapriya, Sathyanarayanan, Kim, Myeong Gon, Im, Sejin, Jeong, Yujin, Surendran, Subramani, Park, Tae-Eon, Yun, Young-Hoon, Lee, Hyunjung, Kim, Tae-Hoon, and Sim, Uk
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Fluorinated polymers are a significant class of functional materials in the field of polymer chemistry. Endowed with remarkable properties, such as high chemical and solvent resistance, enhanced electrical properties, high thermal and electrochemical stability, and low surface energy, they find potential applications in various fields such as chemical processing, electrical/electronic industries, automotive/aircraft industries, medical instrumentations, consumer products, and energy storage or conversion devices. Among a wide variety of commercially significant fluorinated polymers, perfluoropolyether (PFPE) plays a substantial role in energy applications because of its super-hydrophobicity, non-crystallinity, non-flammability, low toxicity, and gas-permeability features. This review briefly confers the properties, production, and significant studies of perfluoropolyether as electrolytes in batteries, followed by a detailed discussion on their role as solid electrolyte interphase (SEI) in metal-ion batteries, oxygen selective membrane (OSM) in metal–air batteries, and as a hydrophobic coating for gas diffusion electrodes in fuel cell applications. Besides, other energy-related applications of PFPE that open up the future scopes of perfluoropolyether in the field of energy storage and conversion devices are also presented.
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- 2023
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17. Energy Level Modulation of Small Molecules Enhances Thermoelectric Performances of Carbon Nanotube-Based Organic Hybrid Materials
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Kim, Tae-hoon and Hong, Jong-In
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Although numerous thermoelectric materials based on single-walled carbon nanotubes (SWNTs) and organic semiconductors have been reported during the past decade, the correlation between energy levels of organic semiconductors and thermoelectric performances of their hybrids is still ambiguous. In this study, we demonstrate that simultaneous modulation of the bandgap and highest occupied molecular orbital levels in organic small molecules (OSMs) largely improves the Seebeck coefficient and thus maximizes the figure of merit (ZT) of SWNT/OSM hybrids. SWNT/CzSwith an enlarged bandgap and reduced barrier energy exhibited a synergistic increment in the Seebeck coefficient (108.7 μV K–1) and power factor (337.2 μW m–1K–2), with the best ZTof 0.058 at room temperature among dopant-free carbon nanotube-hybridized thermoelectrics. The efficient charge carrier transport and reduced thermal conductivity of SWNT/CzSprovided enhanced thermoelectric performance. Our strategy based on energy level modulation could be broadly applied for performance enhancement of organic and hybrid thermoelectric materials.
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- 2022
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18. Predictive Value of Radiologic Central Compartment Atopic Disease for Identifying Allergy and Asthma in Pediatric Patients
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Lee, Kijeong, Kim, Tae Hoon, Lee, Sang Hag, Kang, Chang Ho, Je, Bo-Kyung, and Oh, Saelin
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Introduction: Central compartment atopic disease (CCAD) has recently been suggested as a phenotype of chronic rhinosinusitis (CRS). This study aims to investigate the prevalence of the radiologic CCAD phenotype in CRS within a pediatric population and identify its ability to predict comorbid allergy and asthma.Methods: Computed tomography and endoscopic examination were conducted on pediatric patients with CRS either with or without nasal polyps. Allergen sensitization was determined with the multiple-allergen simultaneous test and skin prick test. Serum total immunoglobulin E (IgE), peripheral blood eosinophil percentage, and presence of asthma were also evaluated.Results: A total of 82 pediatric patients were enrolled. Overall, 55 (67.1%) of the participants demonstrated aeroallergen sensitization, and 31 (18.9%) of the 164 sides of sinuses were radiologically defined to fit the CCAD phenotype. Patients having CRS with the CCAD phenotype had a higher prevalence of aeroallergen sensitization (87.1% vs 62.4%, P= .008), particularly house dust mite (74.2% vs 53.4%, P= .035), and a higher incidence of asthma (16.1% vs 3.8%, P= .010). Additionally, patients having CRS with the CCAD phenotype demonstrated a high serum total IgE levels (51.6% vs 30.1%, P= .023) in comparison to patients having CRS without CCAD.Conclusion: In pediatric CRS, the radiological CCAD phenotype was associated with allergen sensitization and asthma. Furthermore, the CCAD phenotype was associated with high serum total IgE levels, suggesting allergy etiology should be considered with this type of pediatric patients with CRS.
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- 2022
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19. Texture development and grain boundary phase formation in Ce- and Ce-La-substituted Nd-Fe-B magnets during hot-deformation process.
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Kim, Ga-Yeong, Kim, Tae-Hoon, Cha, Hee-Ryoung, Lee, Sang-hyub, Kim, Dong-Hwan, Kim, Yang-Do, and Lee, Jung-Goo
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CRYSTAL grain boundaries ,MAGNETS ,MAGNETIC properties ,REMANENCE ,MATERIALS texture ,COERCIVE fields (Electronics) - Abstract
• The Ce- and Ce-La-substitution for Nd in Nd-Fe-B magnets hinder the texture development and grain boundary phase formation during the hot-deformation process. • The decrease in volume fraction of RE-rich liquid in the grain boundaries by Ce- and Ce-La substitution is a critical reason for the deterioration of magnetic and microstructural properties of Ce- and Ce-La-substituted Nd-Fe-B hot-deformed magnets. • Based on the results, a method to increase both the coercivity and remanence of the Ce- and Ce-La-substituted Nd-saving hot-deformed magnets was developed: intermediate infiltration (I-infiltration). In this study, the influence of Ce- and Ce-La-substitution for Nd in Nd-Fe-B magnets on their magnetic and microstructural changes in the course of the hot-deformation process was investigated to gain insight into further reducing the Nd content in fine-grained Nd-Fe-B hot-deformed magnets. We found that the [001] texture and microstructure of the RE-rich grain boundary phases, which are the factors that determine the remanence and coercivity of hot-deformed magnets, were deteriorated by the Ce- and Ce-La-substitution. This is because the volume fraction of the RE-rich liquid formed in the grain boundaries during the hot-press and hot-deformation decreased due to the Ce- and Ce-La-substitution, thereby increasing the friction between the 2:14:1 grains while the c -axes of grains were aligned by grain rotation and decreasing the RE concentration of grain boundary phases. In particular, the Ce-La-co-substitution further prevented the liquid formation within the grain boundaries of the magnets during hot-press and hot-deformation because the wettability of the RE-rich liquid on the 2:14:1 grains became poor when La was substituted for Nd in the 2:14:1 grains. These results indicate that there is room for further improvement in both the remanence and coercivity of the Ce- and Ce-La-substituted magnets by introducing additional liquid into the grain boundaries prior to hot-press and hot-deformation. By applying the Nd-Cu infiltration process to the melt-spun ribbons (intermediate infiltration, I-infiltration), both the remanence and coercivity of the Nd-saving (Nd 0.7 Ce 0.3)-Fe-B and (Nd 0.7 Ce 0.225 La 0.075)-Fe-B hot-deformed magnets were successfully improved. [ABSTRACT FROM AUTHOR]
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- 2022
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20. Association between Concentration of Air Pollutants and Prevalence of Inflammatory Sinonasal Diseases: A Nationwide Cross-sectional Study
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Han, Munsoo, Choi, Soo Jeong, Jeong, Yujin, Lee, Kijeong, Lee, Tae Hoon, Lee, Sang Hag, and Kim, Tae Hoon
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Background Air pollution is a serious health concern and affects inflammatory sinonasal diseases such as allergic rhinitis (AR) and chronic rhinosinusitis (CRS). Clarifying the relationship between air pollutants and upper respiratory diseases could help the patients.Objective To evaluate the association between the concentration of air pollutants and the prevalence of AR and CRS among South Koreans.Methods In this cross-sectional study, nationwide data were reviewed for participants of the Korean National Health and Nutrition Examination Survey (KNHANES) 2008 to 2012. Participants were surveyed with health questionnaires, examined with endoscopies by otolaryngologists, and tested with serum immunoglobulin E levels. The concentrations of sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and particulate matter with aerodynamic diameters ≤10 µm (PM10) were measured in 16 areas of South Korea. Air pollutant concentrations of geographic districts were matched to each participant's residence. Logistic regression analysis was performed.Results Among 27 863 eligible adults, 3359 and 1606 participants had AR or CRS, respectively. In multivariable logistic regression analysis for AR, PM10showed statistically significant results (odds ratio [OR] = 1.145, 95% confidence interval [CI] = 1.042–1.258). No air pollutants showed statistically significant differences in the prevalence of CRS. In AR, PM10(OR = 1.458, 95% CI = 1.201–1.770) was associated with endoscopic findings of watery rhinorrhea, whereas SO2(OR = 1.202, 95% CI = 1.100–1.313) was associated with pale mucosa.Conclusion The prevalence of AR was significantly associated with PM10concentration. In patients with AR, endoscopic findings of watery rhinorrhea were associated with PM10. However, CRS was not associated with the air pollutant concentrations. Lower concentration of PM10might help managing the clinical symptoms in patients of AR.
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- 2022
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21. Unilateral versus bilateral antegrade cerebral perfusion during surgical repair for patients with acute type A aortic dissection
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Song, Seung Jun, Kim, Wan Kee, Kim, Tae-Hoon, and Song, Suk-Won
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To compare unilateral versus bilateral antegrade cerebral perfusion (ACP) techniques on cerebral protection during acute type A aortic dissection repair.
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- 2022
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22. Synthesis of PtSn4Intermetallic Nanodisks through a Galvanic Replacement Mechanism
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Yu, Jiaqi, Yu, Shen-Wei, Qi, Zhiyuan, Fang, Xiaotian, Kim, Tae-Hoon, Zhou, Lin, Zhang, Sen, and Huang, Wenyu
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Intermetallic compounds with ordered crystal structures are attractive materials with extensive applications in many fields. PtSn4, the most Sn-rich Pt–Sn intermetallic compound discovered so far, has special physical and catalytical properties because of the “Sn–Pt–Sn” layered crystal structure. However, studies on the property of PtSn4have been limited to the single crystal due to the lack of success in preparing PtSn4nanomaterials. Here, starting from Sn nanoparticles, we demonstrated the preparation of monodisperse pure-phase PtSn4intermetallic nanodisks (PtSn4NDs) based on a galvanic replacement mechanism. The structure of the as-synthesized PtSn4NDs was carefully characterized and analyzed. A systematic study on the PtSn4formation mechanism and kinetics confirms that the galvanic replacement mechanism governs the formation of PtSn4NDs. In electrocatalytic furfural reduction, PtSn4NDs effectively suppress the major competitive hydrogen evolution reaction and show faradaic efficiency superior to Pt nanoparticles.
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- 2022
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23. Functional optical coherence tomography of retinal morphophysiological changes during dark adaptation
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Liu, Juan, Jia, Baohua, Cao, Liangcai, Yao, Xincheng, Wang, Yongtian, Nomura, Takanori, Kim, Tae-Hoon, Ding, Jie, and Yao, Xincheng
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- 2022
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24. Upregulation of elafin and cystatin C in the ethmoid sinus mucosa of patients with chronic sinusitis
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Lee, Chang Whan, Kim, Tae Hoon, Lee, Heung Man, Lee, Seung Hoon, Lee, Sung Ho, Yoo, Joon Hyuk, Kim, Yeon Soo, and Lee, Sang Hag
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Sinusitis -- Development and progression ,Sinusitis -- Research ,Gene expression -- Research ,Serine -- Physiological aspects ,Serine -- Genetic aspects ,Serine -- Research ,Cysteine -- Physiological aspects ,Cysteine -- Genetic aspects ,Cysteine -- Research ,Health - Published
- 2009
25. Effectiveness and Safety of Anticoagulation Therapy in Frail Patients With Atrial Fibrillation
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Kim, Daehoon, Yang, Pil-Sung, Sung, Jung-Hoon, Jang, Eunsun, Yu, Hee Tae, Kim, Tae-Hoon, Uhm, Jae-Sun, Kim, Jong-Youn, Pak, Hui-Nam, Lee, Moon-Hyoung, Lip, Gregory Y.H., and Joung, Boyoung
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- 2022
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26. SIRT1 plays an important role in implantation and decidualization during mouse early pregnancy
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Hwang, Yeon Jeong, Sung, Gi-Jun, Marquardt, Ryan, Young, Steven L, Lessey, Bruce A, Kim, Tae Hoon, Cheon, Yong-Pil, and Jeong, Jae-Wook
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Sirtuin 1 (SIRT1) is a member of the sirtuin family that functions to deacetylate both histones and non-histone proteins. Previous studies have identified significant SIRT1 upregulation in eutopic endometrium from infertile women with endometriosis. However, SIRT1 function in the uterus has not been directly studied. Using immunochemistry analysis, we found SIRT1 to be most strongly expressed at GD4.5 and GD5.5 in decidualized cells and at GD7.5 in secondary decidual cells in mouse. To assess the role of SIRT1 in uterine function, we generated uterine Sirt1conditional knockout mice (Pgrcre/+Sirt1f/f; Sirt1d/d). A 6-month fertility trial revealed that Sirt1d/dfemales were subfertile. Implantation site numbers were significantly decreased in Sirt1d/dmice compared with controls at GD5.5. Sirt1d/dimplantation sites at GD4.5 could be divided into two groups, Group #1 with luminal closure and nonspecific COX2 expression compared with controls (14/20) and Group #2 with an open lumen and no COX2 (6/20). In Sirt1d/dGroup #1, nuclear FOXO1 expression in luminal epithelial cells was significantly decreased. In Sirt1d/dGroup #2, nuclear FOXO1 expression was almost completely absent, and there was strong PGR expression in epithelial cells. At GD5.5, stromal PGR and COX2 were significantly decreased in Sirt1d/duterine in the areas surrounding the embryo compared with controls, indicating defective decidualization. An artificially induced decidualization test revealed that Sirt1d/dfemales showed defects in decidualization response. All together, these data suggest that SIRT1 is important for decidualization and contributes to preparing a receptive endometrium for successful implantation.
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- 2022
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27. Electrical Posterior Box Isolation in Repeat Ablation for Atrial Fibrillation
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Kim, Daehoon, Yu, Hee Tae, Kim, Tae-Hoon, Uhm, Jae-Sun, Joung, Boyoung, Lee, Moon-Hyoung, and Pak, Hui-Nam
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This study investigated whether additional electrical posterior box isolation (POBI) may improve the rhythm outcome of repeat ablation in atrial fibrillation (AF).
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- 2022
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28. Age and Outcomes of Early Rhythm Control in Patients With Atrial Fibrillation
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Kim, Daehoon, Yang, Pil-Sung, You, Seng Chan, Jang, Eunsun, Yu, Hee Tae, Kim, Tae-Hoon, Pak, Hui-Nam, Lee, Moon-Hyoung, Lip, Gregory Y.H., Sung, Jung-Hoon, and Joung, Boyoung
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This study sought to investigate whether the effects of early rhythm control differ according to age.
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- 2022
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29. Association of Physical Activity With Primary Cardiac Arrest Risk in the General Population: A Nationwide Cohort Study of the Dose-Response Relationship
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Jin, Moo-Nyun, Yang, Pil-Sung, Yu, Hee Tae, Kim, Tae-Hoon, Lee, Hye Young, Sung, Jung-Hoon, Byun, Young Sup, and Joung, Boyoung
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To quantify the dose-response relationship between moderate to vigorous physical activity and primary cardiac arrest (PCA).
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- 2022
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30. Increased expression of glycoprotein 340 in the ethmoid sinus mucosa of patients with chronic sinusitis
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Kim, Tae Hoon, Lee, Sang Hag, Lee, Heung Man, Jung, Hak Hyun, Lee, Seung Hoon, Cho, Woo Sung, Cinn, Young Gi, Choe, Hwan, Kim, Moo Pil, Yoo, Ik One, and Hwang, Ho Yeon
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Sinusitis -- Diagnosis ,Glycoproteins -- Physiological aspects ,Glycoproteins -- Genetic aspects ,Glycoproteins -- Research ,Nasal mucosa -- Physiological aspects ,Polymerase chain reaction -- Methods ,Health - Published
- 2007
31. Depth-resolved profile features for differentiating arteries and veins in OCT and OCT angiography of the human retina
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Hammer, Daniel X., Joos, Karen M., Palanker, Daniel V., Adejumo, Tobiloba, Kim, Tae-Hoon, Le, David, Son, Taeyoon, Ma, Guangying, and Yao, Xincheng
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- 2022
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32. Long-Term Outcomes of Nasoseptal Perforation Repair Using Anterior Maxillary Sinus Wall as an Interpositional Graft
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Hwang, Jae Woong, Han, Mun Soo, Kang, Sung Hoon, Kwak, Ji Won, Kim, Hyun Keun, Kim, Tae Hoon, and Lee, Sang Hag
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Background Various graft materials have been used to repair nasoseptal perforation, but there is no standardized treatment method. The anterior maxillary sinus wall is flattened in appearance and can be easily obtained in a sufficient amount for a large-sized nasoseptal perforation.Objectives The aim of this study is to determine whether the anterior maxillary sinus wall is suitable as an interpositional graft in the surgical repair of septal or nasoseptal perforation.Methods This is a retrospective review of 21 patients who underwent repair of nasoseptal perforation using anterior maxillary sinus wall as an interpositional graft. The etiology,pre- and post-operative NOSE and GBI score, and perforation size were reviewed. The surgical outcome was considered successful if total closure was achieved after postoperative follow-up.Results 19 of the 21 perforations were successfully repaired with anterior maxillary sinus wall. Failure of the repair was found in 2 patients. Causal etiology of perforation was previous septoplasty in 10 patients, and electrocautery in 1 case, but not identified in 10 cases. The largest size was 2.7 × 2.2 cm. The most common symptoms were epistaxis, crusting, and nasal obstruction. Closure of septal perforation resulted in improved subjective symptoms and quality of life which were evaluated with NOSE and GBI score.Conclusion Anterior maxillary sinus wall as interpositional graft between mucoperichondrial flaps can be used to reliably repair nasoseptal perforations.
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- 2022
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33. Role of SIRT1 and Progesterone Resistance in Normal and Abnormal Endometrium
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Kim, Tae Hoon, Young, Steven L, Sasaki, Tsutomu, Deaton, Jeffrey L, Schammel, David P, Palomino, Wilder Alberto, Jeong, Jae-Wook, and Lessey, Bruce A
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- 2022
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34. Depth-resolved vascular profile features for artery-vein classification in OCT and OCT angiography of human retina
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Adejumo, Tobiloba, Kim, Tae-Hoon, Le, David, Son, Taeyoon, Ma, Guangying, and Yao, Xincheng
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This study is to characterize reflectance profiles of retinal blood vessels in optical coherence tomography (OCT), and to test the potential of using these vascular features to guide artery-vein classification in OCT angiography (OCTA) of the human retina. Depth-resolved OCT reveals unique features of retinal arteries and veins. Retinal arteries show hyper-reflective boundaries at both upper (inner side towards the vitreous) and lower (outer side towards the choroid) walls. In contrast, retinal veins reveal hyper-reflectivity at the upper boundary only. Uniform lumen intensity was observed in both small and large arteries. However, the venous lumen intensity was dependent on the vessel size. Small veins exhibit a hyper-reflective zone at the bottom half of the lumen, while large veins show a hypo-reflective zone at the bottom half of the lumen.
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- 2022
35. Association of proteinuria and hypertension with incident atrial fibrillation in an elderly population: nationwide data from a community-based elderly cohort
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Park, Yoon Jung, Yang, Pil-Sung, Yu, Hee Tae, Kim, Tae-Hoon, Jang, Eunsun, Uhm, Jae-Sun, Pak, Hui-Nam, Lee, Moon-Hyoung, Lip, Gregory Y.H., and Joung, Boyoung
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Supplemental Digital Content is available in the text
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- 2022
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36. Association between exercise habit changes and mortality following a cardiovascular event
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Kang, Dong-Seon, Sung, Jung-Hoon, Kim, Daehoon, Jin, Moo-Nyun, Jang, Eunsun, Yu, Hee Tae, Kim, Tae-Hoon, Pak, Hui-Nam, Lee, Moon-Hyoung, Lip, Gregory, Yang, Pil-Sung, and Joung, Boyoung
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ObjectiveTo investigate the associations between exercise habit changes following an incident cardiovascular event and mortality in older adults.MethodsWe analysed the relationship between exercise habit change and all-cause, cardiovascular and non-cardiovascular deaths in adults aged ≥60 years between 2003 and 2012 who underwent two consecutive health examinations within 2 years before and after diagnosis of cardiovascular disease (CVD). They were categorised into four groups according to exercise habit changes: persistent non-exercisers, exercise dropouts, new exercisers and exercise maintainers. Differences in baseline characteristics were adjusted using inverse probability of treatment weighting.ResultsOf 6076 participants, the median age was 72 (IQR 69–76) years and men accounted for 50.6%. Compared with persistent non-exercisers (incidence rate (IR) 4.8 per 100 person-years), new exercisers (IR 3.5, HR 0.73, 95% CI 0.58 to 0.91) and exercise maintainers (IR 2.9, HR 0.53, 95% CI 0.38 to 0.73) were associated with reduced risk of all-cause death. The rate of non-cardiovascular death was significantly lower in new exercisers (IR 2.3, HR 0.73, 95% CI 0.56 to 0.95) and exercise maintainers (IR 2.3, HR 0.61, 95% CI 0.42 to 0.90) than in persistent non-exercisers (IR 3.2). Also, trends towards reduced cardiovascular death in new exercisers and exercise maintainers were observed (p value for trend <0.001).ConclusionsMore virtuous exercise trajectories in older adults with CVD are associated with lower mortality rates. Our results support public health recommendations for older adults with CVD to perform physical activity.
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- 2022
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37. Self-Catalytic Growth of Elementary Semiconductor Nanowires with Controlled Morphology and Crystallographic Orientation
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Jang, Hyeon-Sik, Kim, Tae-Hoon, Kim, Byeong Geun, Hou, Bo, Lee, In-Hwan, Jung, Su-Ho, Lee, Jae-Hyun, Cha, SeungNam, Yang, Cheol-Woong, Kim, Byung-Sung, and Whang, Dongmok
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While the orientation-dependent properties of semiconductor nanowires have been theoretically predicted, their study has long been overlooked in many fields owing to the limits to controlling the crystallographic growth direction of nanowires (NWs). We present here the orientation-controlled growth of single-crystalline germanium (Ge) NWs using a self-catalytic low-pressure chemical vapor deposition process. By adjusting the growth temperature, the orientation of growth direction in GeNWs was selectively controlled to the ⟨110⟩, ⟨112⟩, or ⟨111⟩ directions on the same substrate. The NWs with different growth directions exhibit distinct morphological features, allowing control of the NW morphology from uniform NWs to nanoribbon structures. Significantly, the VLS-based self-catalytic growth of the ⟨111⟩ oriented GeNW suggests that NW growth is possible for single elementary materials even without an appropriate external catalyst. Furthermore, these findings could provide opportunities to investigate the orientation-dependent properties of semiconductor NWs.
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- 2021
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38. Enzymatic transformation products of phloretin as potent antiadipogenic compounds
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Jeong, Gyeong Han, Cho, Jae-Hyeon, Park, Eui Kyun, and Kim, Tae Hoon
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Enzymatic structure modification of the representative chalcone phloretin (1) with polyphenol oxidase from Agaricus bisporusorigin produced 2 new biphenyl-type phloreoxin (2) and phloreoxinone (3), and a previously undescribed (2R)-5,7,3′,5′-tetrahydroxyflavanone (4). The structure of these new oxidized products 2-4elucidated by interpreting the spectroscopic data (NMR and FABMS) containing the absolute stereochemistry is established by the analysis of the circular dichroism spectrum. Compared to the original phloretin, the new products (2) and (3) showed highly improved antiadipogenic potencies both toward pancreatic lipase and accumulation of 3T3-L1 cells. Also, phloreoxin (2) effectively inhibited the expression of C/EBPβ, PPARγ, and aP2 at the mRNA level in the 3T3 adipocytes. Thus, phloreoxin (2), containing a biphenyl moiety catalyzed by A. bisporuspolyphenol oxidase, have the potential to influence the antiadipogenic capacity.Graphical AbstractEnzymatic oxidation products 2and 3of phloretin as potent antiadipogenic effects.
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- 2021
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39. Coronary CT Angiography CAD-RADS versus Coronary Artery Calcium Score in Patients with Acute Chest Pain
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Lee, Ji Won, Kim, Jin Young, Han, Kyunghwa, Im, Dong Jin, Lee, Kye Ho, Kim, Tae Hoon, Park, Chul Hwan, and Hur, Jin
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The Coronary Artery Disease Reporting and Data System score has incremental prognostic value compared with coronary artery calcium score in predicting future major adverse cardiovascular events in patients presenting to the emergency department with chest pain.
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- 2021
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40. PSXI-28 Nitrogen Footprint Assessment of Korean Native Beef Cattle Farms: Uncertainty Analysis and Mitigation Scenarios
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Byun, Jun Suk, Kim, Tae Hoon, Ibidhi, Ridha, Bharanidharan, Rajaraman, Lee, Yookyung, and Kim, Kyoung Hoon
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Nitrogen (N) lost during beef cattle production accompanies various environmental impacts and has become an increasing concern among agricultural stakeholders. The objective of this study was to quantify the N footprint (NF) of Hanwoo beef cattle production in Korea at the farm gate through a life cycle assessment methodology. Field surveys were conducted on 106 farms across nine provinces to evaluate the NF of Hanwoo beef farms. N losses were calculated using emission factors using the refined Intergovernmental Panel on Climate Change (IPCC) guideline and expressed as NF [g N lost/kg of live body weight (LBW)]. Uncertainty and sensitivity analyses were deployed to evaluate the precision of the results and to quantify the variability of the input data. The NF was averaged 132.8 (±61.9) g N/kg LBW. Volatilization was the greatest contributing factor, followed by leaching and denitrification, each representing 68.4, 21.4, and 10.1 percent of the NF, respectively. The uncertainty of the output data was found to be 46.6 percent and was highly associated with emission factors uncertainties. We simulated four feasible mitigation scenarios that are cost effective and do not penalize productivity, and evaluated their capacity for reducing NF of meat: dietary modifications to decrease animal N excretion rates by adjusting the CP and rumen undegradable protein content for steers and fattening cows (A), microorganism additives to reduce volatilization from housing and manure storages through processing excess ammonium to synthesize microbial protein (B), using manure as land fertilizer instead of synthetic fertilizers to decrease denitrification from rice cultivation, and leaching and volatilization from all field types(C), and distributing straw-derived biochar (10 to 20 ton/ha) to the field after fertilizer application to reduce losses from crop production (D).Combining these scenarios demonstrated the potential to reduce NF by 12.3 percent. Overall, our study provides a national metric that can be used to communicate the N uses impact of Korean beef production. The analyses indicate that more precise results could be achieved with future endeavors toward developing country-specific emission factors. Integrating all four scenarios was shown to be the most effective approach to reducing the NF of beef production.
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- 2023
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41. Coercivity improvement in Nd–Cu infiltrated Nd-Fe-B hot-deformed magnets by controlling microstructure of initial HDDR powders
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Yoo, Jae-Gyeong, Cha, Hee-Ryoung, Kim, Tae-Hoon, Kim, Dong-Hwan, Kim, Yang-Do, and Lee, Jung-Goo
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We have studied influence of the microstructure of initial hydrogenation-disproportionation-desorption-recombination (HDDR) treated isotropic powders on the magnetic and microstructural properties of Nd–Cu infiltrated Nd-Fe-B hot-deformed magnets. To control the microstructure of the initial HDDR powders, the starting strip-cast alloys were heat-treated prior to the HDDR process (HDDR powder A). Compared to the HDDR powders prepared from the un-treated strip-casts (HDDR powder B), non-uniform and discontinuous Nd-rich intergranular phases were formed in the HDDR powder A. Therefore, most of the Nd-rich phases in the HDDR powder A were agglomerated at the triple junctions after the hot-deformation (Hot-deformed magnet A). In contrast, homogeneous Nd-rich intergranular phases enveloping the laterally elongated grains are observed in the hot-deformed HDDR powder B (Hot-deformed magnet B). As a result, the coercivity of hot-deformed magnet A is lower than that of the hot-deformed magnet B. Interestingly, after the Nd–Cu infiltration, the coercivity of hot-deformed magnet A increases more rapidly than that of the hot-deformed magnet B because the faster diffusion of liquid Nd–Cu viathe c-plane intergranular phases occurs in the hot-deformed magnet A, while the agglomeration of Nd–Cu into the triple junctions occurs in the hot-deformed magnet B. High resolution transmission electron microscopy showed that the Nd–Cu infiltration on the hot-deformed magnet A leads to the formation of thicker and non-ferromagnetic intergranular phases on the (001) planes of Nd2Fe14B grains, resulting in the magnetic isolation of individual grains and increase of pinning force against the domain wall motion.
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- 2021
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42. Non-Surgical Animal Model of Gastroesophageal Reflux Disease by Overeating Induced in Mice
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Nu-Ri, IM, Kim, Byoungjae, Jung, Kwang-Yoon, Kim, Tae Hoon, and Baek, Seung-Kuk
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Previous animal models of gastroesophageal reflux disease (GERD) were not physiological and required a variety of surgical procedures. Therefore, the animal model developed by conditions that are similar to the pathogenesis of GERD is necessary. The aim is to establish a non-surgical animal model with GERD caused by overeating induced in mice. To induce mice to overeat, we designed dietary control protocols including repetitive fasting and feeding. The esophageal tissues were evaluated with GERD markers to prove the establishment of a GERD animal model. Mice fasted every other day (group 2) showed more pronounced overeating feature and demonstrated evident changes similar to the macroscopic and microscopic findings of GERD, the expressions of inducible nitric oxide synthase and substance P were stronger. The higher frequency of fasting and overeating could cause GERD effectively. The dietary control can make mice overeat, which elicits the change of lower esophageal mucosa similar to GERD. Thus, the overeating-induced mouse may be used as a GERD mouse model.
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- 2021
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43. Kinetics of Magnetic Skyrmion Crystal Formation from the Conical Phase
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Kim, Tae-Hoon, Zhao, Haijun, Ong, Phuong-Vu, Jensen, Brandt A., Cui, Baozhi, King, Alexander H., Ke, Liqin, and Zhou, Lin
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The particle-like magnetic skyrmion or skyrmion lattice (SkX) formation has promoted strong application and fundamental science interests. Despite extensive research, the kinetic of the SkX development is much less understood because of the ultrafast spin rotation and high sensitivity to external perturbations. Here, using in situLorentz transmission electron microscopy, we successfully measured the dynamics of SkX formation from the conical phase with precise control of both the temperature and the magnetic field. We discovered that the Avrami equation can accurately describe the transition process with an initial Avrami constant around 1, suggesting that the rate-limiting step for the quasiparticle lattice formation is one-dimensional heterogeneous nucleation of individual skyrmions. A modified Arrhenius rate law is established, with an energy barrier that has a square-root dependence on temperature and a quadratic dependence on the magnetic field. This study paves the way toward precise and predictable manipulation of topological spin structures.
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- 2021
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44. TRPV4-Mediated Epithelial Junction Disruption in Allergic Rhinitis Triggered by House Dust Mites
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Lee, Kijeong, Byun, Junhyoung, Kim, Byoungjae, Yeon, Jiwoo, Tai, Junhu, Lee, Sang Hag, and Kim, Tae Hoon
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Background Epithelial barrier disruption is a crucial feature of allergic rhinitis (AR). Previous reports have indicated the role of transient receptor potential vanilloid (TRPV) 4 in regulating the intercellular junctions in various cells. However, the role of TRPV4 and its regulation by T helper 2 cell cytokines in the epithelial cells of patients with AR remains unclear.Objective We aimed to elucidate the expression of TRPV4 in nasal epithelial cells and its cytokine-induced regulation, and to reveal its role in house dust mite-induced junction disruption in AR.Methods The expression of TRPV4 in nasal epithelial cells was measured using real-time polymerase chain reaction, western blot, and immunohistochemical assays, and the expression levels were compared between the patients with AR and healthy controls. Altered expression of TRPV4 was induced in cultured nasal epithelial cells by stimulation of interleukin (IL) 4, IL-13, and tumor necrosis factor alpha. In addition, expression of E-cadherin and zonula occludens 1 was induced in Der p 1-stimulated epithelial cells by treatment with either a TRPV4 agonist (GSK1016790A) or a TRPV4 antagonist (RN1734).Results TRPV4 expression was increased in epithelial cells harvested from the affected turbinates compared to those from the normal turbinates. The stimulation of cultured epithelial cells with IL-4 and IL-13 resulted in TRPV4 upregulation. Additionally, E-cadherin and zonula occludens 1 expression levels decreased in the cultured epithelial cells treated with GSK1016790A after stimulation with Der p 1, whereas Der p 1 stimulation alone showed no effect on junctional protein expression.Conclusions Increased TRPV4 expression occurred in epithelial cells harvested from patients with AR and epithelial cells stimulated by Th2 cytokines. Decreased junctional protein expression in epithelial cells after the stimulation by house dust mite allergen with TRPV4 agonist indicates a possible role of TRPV4 in the pathogenesis of allergen-induced epithelial barrier disruption in AR.
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- 2021
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45. Functional optoretinography: concurrent OCT monitoring of intrinsic signal amplitude and phase dynamics in human photoreceptors
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Ma, Guangying, Son, Taeyoon, Kim, Tae-Hoon, and Yao, Xincheng
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Intrinsic optical signal (IOS) imaging promises a noninvasive method for objective assessment of retinal function. This study demonstrates concurrent optical coherence tomography (OCT) of amplitude-IOS and phase-IOS changes in human photoreceptors. A new procedure for differential-phase-mapping (DPM) is validated to enable depth-resolved phase-IOS imaging. Dynamic OCT revealed rapid amplitude-IOS and phase-IOS changes, which occur almost right away after the stimulus onset. These IOS changes were predominantly observed within the photoreceptor outer segment (OS), particularly two boundaries connecting to the inner segment and retinal pigment epithelium. The comparative analysis supports that both amplitude-IOS and phase-IOS attribute to transient OS morphological change associated with phototransduction activation in retinal photoreceptors. A simulation modeling is proposed to discuss the relationship between the photoreceptor OS length and phase-IOS changes.
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- 2021
46. Molecular hybridization based on (−)-epigallocatechin gallate as a new class of antiglycation agents
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Jeong, Gyeong Han, Park, Seungil, Kim, Seong Bong, Jo, Cheorun, and Kim, Tae Hoon
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(−)–Epigallocatechin gallate (EGCG) and olivetol hybrid molecules 1-4were conveniently synthesized using dielectric barrier discharge plasma irradiation. The structures of these unprecedented hybrid molecules were determined by interpretation of spectroscopic data. The unusual hybrid 1showed improved antiglycation potency toward the advanced formation of glycation end products than the original EGCG and olivetol. The novel hybrid 1is an interesting new class of antiglycation candidate that requires further investigation.Graphical AbstractA new convenient method was established for simple green synthesis of methylene-bridged (−)-epigallocatechin gallate and olivetol hybrid molecules 1-4using cold plasma apparatus.
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- 2021
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47. Virtually structured detection for super-resolution ophthalmoscopy of human photoreceptors
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Hammer, Daniel X., Joos, Karen M., Palanker, Daniel V., Kim, Tae-Hoon, Lu, Yiming, Son, Taeyoon, Le, David, and Yao, Xincheng
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- 2021
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48. Plasma-Induced Degradation of Quercetin Associated with the Enhancement of Biological Activities
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Kim, Tae Hoon, Lee, Jaemin, Kim, Hyun-Joo, and Jo, Cheorun
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Nonthermal plasma is a promising technology to improve the safety and to extend the shelf-life of various minimally processed foods. However, research on plasma-induced systemic degradation related to changes in chemical structure and biological activity is still very limited. In this study, the enhancement of biological activity and the mechanism of degradation of the most common type of flavonol, quercetin, induced by a dielectric barrier discharge (DBD) plasma were investigated. Quercetin is dissolved in methanol and exposed to nonthermal DBD plasma for 5, 10, 20, and 30 min. The quercetin treated with the plasma for 20 min showed rapidly increased α-glucosidase inhibitory and radical scavenging activities compared to those of parent quercetin. The structures of the degradation products 1–3from the quercetin treated with the plasma for 20 min were isolated and characterized by interpretation of their spectroscopic data. Among the generated products, (±)-alphitonin (1) exhibited significantly improved antidiabetic and antioxidant properties compared to those of the parent quercetin. The antidiabetic and antioxidant properties were measured by α-glucosidase inhibition and 1,1-diphenyl-2-picrylhydrazyl radical scavenging assays. These results suggested that structural changes in quercetin induced by DBD plasma might be attributable to improving the biological activity.
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- 2024
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49. Transcriptomic changes in eutopic endometrium and ectopic lesions during endometriosis progression in a mouse model
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Li, Rong, Tran, Dinh Nam, Lessey, Bruce A., Young, Steven L., Kim, Tae Hoon, and Jeong, Jae-Wook
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To identify the transcriptomic changes of ectopic lesions and eutopic endometrial tissues during the progression of endometriosis, we performed transcriptomic analysis in the eutopic endometrium and ectopic lesions.
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- 2024
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50. Racial Differences in Bleeding Risk: An Ecological Epidemiological Study Comparing Korea and United Kingdom Subjects
- Author
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Kang, Dong-Seon, Yang, Pil-Sung, Kim, Daehoon, Jang, Eunsun, Yu, Hee Tae, Kim, Tae-Hoon, Sung, Jung Hoon, Pak, Hui-Nam, Lee, Moon-Hyoung, Lip, Gregory Y.H., and Joung, Boyoung
- Published
- 2024
- Full Text
- View/download PDF
Catalog
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