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result(s) for
"Lee, Jinsun"
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Restructuring highly electron-deficient metal-metal oxides for boosting stability in acidic oxygen evolution reaction
2021
The poor catalyst stability in acidic oxidation evolution reaction (OER) has been a long-time issue. Herein, we introduce electron-deficient metal on semiconducting metal oxides-consisting of Ir (Rh, Au, Ru)-MoO
3
embedded by graphitic carbon layers (IMO) using an electrospinning method. We systematically investigate IMO’s structure, electron transfer behaviors, and OER catalytic performance by combining experimental and theoretical studies. Remarkably, IMO with an electron-deficient metal surface (Ir
x+
; x > 4) exhibit a low overpotential of only ~156 mV at 10 mA cm
−2
and excellent durability in acidic media due to the high oxidation state of metal on MoO
3
. Furthermore, the proton dissociation pathway is suggested via surface oxygen serving as proton acceptors. This study suggests high stability with high catalytic performance in these materials by creating electron-deficient surfaces and provides a general, unique strategy for guiding the design of other metal-semiconductor nanocatalysts.
The poor catalyst stability for oxygen evolution in acidic media has been a long-time issue. Here, authors demonstrate iridium on MoO
3
exhibits a low overpotential for oxygen evolution and excellent durability in acidic media due to the high oxidation state of iridium metal on MoO
3
.
Journal Article
Moving beyond bimetallic-alloy to single-atom dimer atomic-interface for all-pH hydrogen evolution
2021
Single-atom-catalysts (SACs) afford a fascinating activity with respect to other nanomaterials for hydrogen evolution reaction (HER), yet the simplicity of single-atom center limits its further modification and utilization. Obtaining bimetallic single-atom-dimer (SAD) structures can reform the electronic structure of SACs with added atomic-level synergistic effect, further improving HER kinetics beyond SACs. However, the synthesis and identification of such SAD structure remains conceptually challenging. Herein, systematic first-principle screening reveals that the synergistic interaction at the NiCo-SAD atomic interface can upshift the d-band center, thereby, facilitate rapid water-dissociation and optimal proton adsorption, accelerating alkaline/acidic HER kinetics. Inspired by theoretical predictions, we develop a facile strategy to obtain NiCo-SAD on N-doped carbon (NiCo-SAD-NC) via in-situ trapping of metal ions followed by pyrolysis with precisely controlled N-moieties. X-ray absorption spectroscopy indicates the emergence of Ni-Co coordination at the atomic-level. The obtained NiCo-SAD-NC exhibits exceptional pH-universal HER-activity, demanding only 54.7 and 61 mV overpotentials at −10 mA cm
−2
in acidic and alkaline media, respectively. This work provides a facile synthetic strategy for SAD catalysts and sheds light on the fundamentals of structure-activity relationships for future applications.
While single, dispersed atoms enable efficient atomic utilization, controllably preparing single-atom dimers remains challenging. Here, authors prepare nickel-cobalt single-atom dimers as high-performance pH-universal H
2
evolution electrocatalysts.
Journal Article
Eribulin Mesylate Improves Cisplatin-Induced Cytotoxicity of Triple-Negative Breast Cancer by Extracellular Signal-Regulated Kinase 1/2 Activation
2022
Background and Objectives; Triple-negative breast cancer (TNBC) is associated with poor patient prognosis because of its multiple molecular features. Thus, more effective treatment for TNBC is urgently needed. This study determined the possible involvement of ERK1/2 activation in cisplatin-induced cytotoxicity in TNBC by providing additional eribulin treatment. Materials and Methods; We investigated cell viability and apoptosis caused by eribulin, cisplatin, or co-treatment in HCC38, MDA-MB-231, and SKBR3 human breast cancer cells. Results; Cisplatin significantly lowered cell viability and caused high apoptotic cell death in all breast cancer cell lines. The viability of TNBC cells was significantly lower in the group co-treated with cisplatin and eribulin than in the cisplatin-only treatment group. Additional eribulin treatment significantly enhanced PARP cleavage and caspase-3 activity in cisplatin-treated TNBC cells. Moreover, cisplatin treatment activated ERK1/2 in all breast cancer cell lines. The cisplatin and eribulin combination synergistically activated ERK1/2 in TNBC cells compared with the cisplatin-only treatment. Administration of the ERK1/2 inhibitor PD98059 increased the viability of TNBC cells treated with cisplatin plus eribulin. Conclusions; Eribulin could synergize the cytotoxic and apoptotic activities of cisplatin and increase ERK1/2 activation, thus enhancing anti-cancer effects against TNBC cells.
Journal Article
Improvement in Biocompatibility and Biointegration of Human Acellular Dermal Matrix through Vacuum Plasma Surface Treatment
by
Lee, Jeonghoon
,
Lee, Byungchul
,
Lee, Jinsun
in
Adsorption
,
Atmospheric pressure
,
Biocompatibility
2024
Efforts are ongoing to enhance the functionality of human acellular dermal matrices (hADMs), which are extensively utilized in reconstructive surgeries. Among these efforts, plasma treatments, particularly vacuum plasma treatments, have recently emerged in the medical field. This study aims to investigate the efficacy of a vacuum plasma treatment in enhancing the biocompatibility and biointegration of hADMs. Utilizing a plasma activator (ACTILINK reborn, Plasmapp Co., Ltd., Daejeon, Republic of Korea), hADMs were treated and evaluated through in vitro and in vivo analyses. Hydrophilicity changes were gauged by the blood absorption times, while SEM imaging was used to analyze physical surface deformation. Protein adsorption was measured with fluorescently labeled bovine serum albumin and fibronectin. For the in vivo study, mice were implanted with plasma-treated and untreated hADMs, and the post-implantation effects were analyzed through histological and immunofluorescence microscopy. The plasma-treated hADMs demonstrated a significantly enhanced hydrophilicity compared to the untreated samples. SEM imaging confirmed the maintenance of the microroughness after the treatment. The treated hADMs showed a significant reduction in fibronectin adsorption, a critical factor for cellular adhesion. In vivo, the plasma-treated hADMs exhibited reduced capsule formation and enhanced fibroblast infiltration, indicating improved biocompatibility and integration. These findings highlight the potential of a plasma treatment to enhance the performance of hADMs in clinical settings, offering a promising avenue for improving reconstructive surgery outcomes.
Journal Article
Selective Sentinel Node Plus Additional Non-Sentinel Node Biopsy Based on an FDG-PET/CT Scan in Early Breast Cancer Patients: Single Institutional Experience
2009
Background
This study was designed to determine whether a preoperative fluorodeoxyglucose (FDG) positron emission tomography (PET) integrated with computed tomography (CT) (FDG-PET/CT) could be used as a guide for axillary node dissection (AND) or sentinel lymph node biopsy (SNB) in breast cancer patients.
Methods
Between February 2007 and April 2008, we performed FDG-PET/CT scans in 137 biopsy-proven breast cancer patients planning to have an SNB to select patients for either AND (PET/CT N+) or SNB (PET/CT N0). In performing SNB, we also performed additional non-SNB (ADD), which was enlarged at the lower axilla.
Results
Twenty-seven patients with positive scans underwent complete AND as a primary procedure, and 110 patients with negative scans underwent SNB + ADD. There were 8 cases of false negative scans, and no case of false positive scan. The overall sensitivity, specificity, positive predictive value, and overall accuracy of FDG-PET/CT in predicting axillary metastasis were 77.1%, 100%, 100%, and 94.2%, respectively. In a subset of 110 patients with SNB + ADD, 104 patients had histologically negative SN, and 6 patients had positive SN in frozen section. Among 110 SNB + ADD cases, there were only 8 cases (7.3%) of positive axillary basins in permanent biopsy, including two cases of late positives that had micrometastases in the SN only. Through selective SNB + ADD based on an FDG-PET/CT, we have spared 27 unnecessary SNBs (true positive scans).
Conclusions
FDG-PET/CT is a specific imaging modality for predicting axillary node metastasis, and allows for a selective approach to either AND or SNB. A selective SNB + ADD based on an FDG-PET/CT reduced both unnecessary SNBs and positive axillary basins, enhancing the identification rates of SN and the accuracy of SNB.
Journal Article
Clinical manifestations of headache in children younger than 7 years
by
Kang, Bu Seon
,
Kwon, Hyeok Hee
,
Choi, Jin Hyuk
in
Age groups
,
Blood pressure
,
Children & youth
2018
Purpose Headache is a common symptom during childhood. It is usually persistent and requires special care. This study aimed to identify the characteristics of headache in children <7 years of age. Methods We reviewed 3 years of clinical files on children <7 years of age with a chief complaint of headache. Results This study included 146 children (66 males, 80 females; mean age, 5.5±1.0 years). Mean symptom duration was 5.8±7.9 months. Attack durations were longer than 2 hours in 31 patients, shorter than 2 hours in 70 patients, and unchecked in 45 patients. Attack frequency was 15.1±10.6 times per month. Pain locations and characteristics were also variable. Mean pain severity score was 5.1±2.2 on the visual analog scale. Of 38 patients who underwent electroencephalography, 9 showed positive findings. Of 41 who underwent brain magnetic resonance imaging, 20 showed positive findings. The diagnoses were migraine (including probable migraine) in 34, tension-type headache in 5, and congenital malformations in 3. Medications were used in 29 patients: acetaminophen in 17, ibuprofen in 8, naproxen sodium in 1, and topiramate or amitriptyline in 3. Conclusion In children aged <7 years, headache has a relatively benign course, but detailed history taking is needed for more accurate diagnosis.
Journal Article
ERK-driven autophagy enhances synergy of eribulin and cisplatin in triple-negative breast cancer
2025
Triple-negative breast cancer (TNBC) remains one of the most aggressive subtypes of breast cancer with limited therapeutic options, especially in resource-limited settings. The present study investigated the mechanistic synergy of eribulin and cisplatin in TNBC, with a focus on ERK-driven autophagy. MDA-MB-231 TNBC cells were treated with eribulin and cisplatin. Viability, apoptosis, autophagy and ERK activation were assessed using Cell Counting Kit-8 assays, flow cytometry, western blotting and fluorescence microscopy. The drug combination enhanced ERK activation and induced autophagy, significantly increasing cell death. ERK inhibition reversed these effects, confirming its role in mediating synergy. The present findings provide a mechanistic rationale for an affordable combination therapy that may enhance TNBC treatment efficacy, particularly in resource-limited settings.
Journal Article
In Vivo Efficacy of an Injectable Human Acellular Dermal Matrix
2023
Background
Human acellular dermal matrix (hADM) has found applications in a variety of settings, particularly in breast surgery. The most common hADM is a sheet. Recently, an injectable hADM has been introduced; we compared the biocompatibility and long-term structural integrity of, an injectable hADM and a sheet-type hADM in mice.
Methods
An injectable hADM (experimental group) and a sheet-type hADM (control group) were implanted into sub-panniculus pockets on the backs of 50 mice. The animals were sacrificed 2, 4, 8, 12, or 24 weeks later and the hADMs and surrounding tissues were recovered and stained for histopathological analyses. The microscopic endpoints included the thickness of the hADM and capsule around the hADM, and the extents of fibroblast proliferation and neovascularization.
Results
No animal developed a complication or infection. The capsule was significantly thinner in the experimental than the control group. There were no significant differences between groups in the hADM thickness. Microscopically, the fibroblast density inside the hADM was significantly higher in the experimental group. The fibroblasts inside of the hADM lay significantly deeper in the experimental group. Similarly, the experimental group exhibited significantly deeper microvessels inside the hADM.
Conclusions
The injectable hADM had a thinner capsule thickness (more biocompatible), than the sheet-type hADM. It maintained its thickness as well as the sheet-type hADM and had a more fibroblast proliferation and neovascularization. This means the tissue incorporation and long-term structural integrity of the injectable hADM may be as good as or better than that of the sheet-type hADM.
No Level Assigned
This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors
www.springer.com/00266
.
Journal Article
Effect of Earthquake Motion on The Permanent Displacement of Embankment Slopes
by
Liu, Qihang
,
Lee, Jinsun
,
Park, Heon-Joon
in
Beam theory (structures)
,
Bending moments
,
Boundary conditions
2019
Permanent displacement of slopes is key data for designing the slope in performance-based seismic design. To estimate the permanent displacement of a slope, empirical as well as numerical methods should be adopted. However, the results of these methods are highly dependent on both stationary and nonstationary ground-motion characteristics. This paper aims to find the most influential nonstationary characteristics of earthquakes on the permanent displacement of slopes. Two different numerical methods, Newmark’s sliding-block and response-history analysis, are used for a total of 47 real earthquake records. The records are classified into three groups based on their event characteristics. They are spectrally matched before analysis to the target spectrum to eliminate the effect of stationary characteristics. The amount of permanent displacement obtained from the analyses is different for varying input motions. The intensity-based parameters, destructiveness potential factor, Arias intensity, and characteristic intensity play an important role on the permanent displacement of the slope. The results of this study are expected to yield judgment criteria for designers to select appropriate ground motion to evaluate the permanent displacement of slopes under seismic loading.
Journal Article
Effect of Strong Motion on Liquefaction-Induced Settlement of Shallow Foundations using 3D Numerical Analysis
2024
Liquefaction-induced settlement of shallow foundations is the result of bearing capacity failure in undrained conditions and sedimentary settlement during the post-liquefaction process. The bearing capacity of a shallow foundation is highly dependent on the size and dimensions of its footprint. In addition, the reduction in shear strength in liquefiable soil, a key parameter for estimating bearing capacity, depends on the excess pore water pressure generated during an earthquake. This study aims to investigate the impact of earthquake motion on the extent of liquefaction-induced settlement in shallow foundations. A parametric study was conducted by varying the input earthquake motions in a three-dimensional response history analysis to directly consider the interaction between the soil and superstructures. The numerical analysis model constructed for the parametric study was rigorously calibrated using a reference dynamic centrifuge test in a prototype scale. The effects of the horizontal boundary and drainage conditions in the numerical model were closely examined during calibration. The parametric study results indicate that the intensity measures of an earthquake, which quantify the energy associated with the number of reversals, exhibit a close correlation with the resulting liquefaction-induced settlement as opposed to other conventional earthquake motion parameters, such as peak acceleration, magnitude, and frequency.
Journal Article