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Low-frequency pulsed electromagnetic field pretreated bone marrow-derived mesenchymal stem cells promote the regeneration of crush-injured rat mental nerve

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Neural Regeneration Research 2018年第1期13卷 145-153页

作者： NaRi Seo sung-ho lee Kyung Won Ju JaeMan Woo BongJu Kim SoungMin Kim Jeong Won Jahng Jong-ho lee Department of Oral and Maxillofacial Surgery Graduate School of Dentistry Seoul National University Seoul South Korea Department of Oral and Maxillofacial Surgery Seoul National University Dental Hospital Seoul South Korea Dental Research Institute Seoul National University Seoul South Korea Clinical Translational Research Center for Dental Science (CTRC) Seoul National University Dental Hospital Seoul South Korea

Bone marrow-derived mesenchymal stem cells （BMSCs） have been shown to promote the regeneration of injured peripheral nerves. Pulsed electromagnetic field （PEMF） reportedly promotes the proliferation and neuronal differentiation of BMSCs. Low-frequency PEMF can induce the neuronal differentiation of BMSCs in the absence of nerve growth factors. This study was designed to investigate the effects of low-frequency PEMF pretreatment on the proliferation and function of BMSCs and the effects of low-frequency PEMF pre-treated BMSCs on the regeneration of injured peripheral nerve using in vitro and in vivo *** in vitro experiments, quantitative DNA analysis was performed to determine the proliferation of BMSCs, and reverse transcription-polymerase chain reaction was performed to detect S100 （Schwann cell marker）, glial fibrillary acidic protein （astrocyte marker）, and brain-derived neurotrophic factor and nerve growth factor （neurotrophic factors） mRNA expression. In the in vivo experiments, rat models of crush-injured mental nerve established using clamp method were randomly injected with low-frequency PEMF pretreated BMSCs, unpretreated BMSCs or PBS at the injury site （1 × 106 cells）. DiI-labeled BMSCs injected at the injury site were counted under the fluorescence microscope to determine cell survival. One or two weeks after cell injection, functional recovery of the injured nerve was assessed using the sensory test with von Frey filaments. Two weeks after cell injection, axonal regeneration was evaluated using histomorphometric analysis and retrograde labeling of trigeminal ganglion neurons. In vitro experiment results revealed that low-frequency PEMF pretreated BMSCs proliferated faster and had greater mRNA expression of growth factors than unpretreated BMSCs. In vivo experiment results revealed that compared with injection of unpretreated BMSCs, injection of low-frequency PEMF pretreated BMSCs led to higher myelinated axon count and axon density and more Di

关键词： nerve regeneration mesenchymal stem cells low-frequency pulsed electromagnetic field peripheral nerve injury crush-injured mental nerve

Attractor landscape analysis of the cardiac signaling network reveals mechanism-based therapeutic strategies for heart failure

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Journal of Molecular Cell Biology 2018年第3期10卷 180-194页

作者： Daebeom Park ho-sung lee Jun Hyuk Kang Seon-Myeong Kim Jeong-Ryeol Gong Kwang-Hyun Cho Laboratory for Systems Biology and Bio-inspired Engineering Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea Graduate School of Medical Science and Engineering KAIST Daejeon 34141 Republic of Korea

Apoptosis and hypertrophy of cardiomyocytes are the primary causes of heart failure （HF）, a global leading cause of death, and are regulated through the complicated intracellular signaling network, limiting the development of effective treatments due to its complexity. To identify effective therapeutic strategies for HF at a system level, we develop a large-scale comprehensive mathematical model of the cardiac signaling network by integrating all available experimental evidence. Attractor landscape analysis of the network model identifies distinct sets of control nodes that effectively suppress apoptosis and hypertrophy of cardiomyocytes under ischemic or pressure overload-induced HF, the two major types of HF. Intriguingly, our system-level analysis suggests that intervention of these control nodes may increase the efficacy of clinical drugs for HF and, of most importance, different combinations of control nodes are suggested as potentially effective candidate drug targets depending on the types of HF. Our study provides a systematic way of developing mechanism-based therapeutic strategies for HF.

关键词： heart failure mathematical modeling cardiac signaling network systems analysis disease mechanism mechanism-based therapeutic strategy systems biology

Enhanced prediction of anisotropic deformation behavior using machine learning with data augmentation

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Journal of Magnesium and Alloys 2024年第1期12卷 186-196页

作者： Sujeong Byun Jinyeong Yu Seho Cheon Seong ho lee sung Hyuk Park Taekyung lee School of Mechanical Engineering Pusan National UniversityBusan 46241South Korea School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566South Korea

Mg alloys possess an inherent plastic anisotropy owing to the selective activation of deformation mechanisms depending on the loading *** characteristic results in a diverse range of flow curves that vary with a deformation *** study proposes a novel approach for accurately predicting an anisotropic deformation behavior of wrought Mg alloys using machine learning(ML)with data *** developed model combines four key strategies from data science:learning the entire flow curves,generative adversarial networks(GAN),algorithm-driven hyperparameter tuning,and gated recurrent unit(GRU)*** proposed model,namely GAN-aided GRU,was extensively evaluated for various predictive scenarios,such as interpolation,extrapolation,and a limited dataset *** model exhibited significant predictability and improved generalizability for estimating the anisotropic compressive behavior of ZK60 Mg alloys under 11 annealing conditions and for three loading *** GAN-aided GRU results were superior to those of previous ML models and constitutive *** superior performance was attributed to hyperparameter optimization,GAN-based data augmentation,and the inherent predictivity of the GRU for *** a first attempt to employ ML techniques other than artificial neural networks,this study proposes a novel perspective on predicting the anisotropic deformation behaviors of wrought Mg alloys.

关键词： Plastic anisotropy Compression Annealing Machine learning Data augmentation

Strengthening mechanisms analysis and tailoring of bimodal grain structures for enhanced strength in CoCrFeMnNi high-entropy alloys

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Rare Metals 2024年第8期43卷 3893-3903页

作者： Jaesoung lee Seulgi Kim Taehyun Kwon Young II Kim Suyeon Kim sung ho Song Bin lee Dongju lee Department of Urban Energyand Environmental EngineeringChungbuk National UniversityCheongju 28644Republic of Korea Division of Advanced Materials Engineering Kongju National UniversityChungnam 330-717Republic of Korea Department of Advanced Materials Engineering for Information and Electronics Integrated-Education Institute for Frontier Science and Technology(BK21 Four)Kyung Hee UniversityYongin17104Republic of Korea

The CoCrFeMnNi high-entropy alloys(HEAs)with a(face-centered cubic) FCC structure has garnered considerable attention for its exceptional ductility and strain hardening ***,its yield strength is insufficient for structural *** this study,strengthening mechanisms in these HEAs were investigated to gain insight into the mechanical properties according to alloy powder ***,we present a novel approach to achieve both high strength and high ductility through the creation of a bimodal structure consisting of both coarse and fine grains via gas atomization and spark plasma sintering processes.A bimodally structured HEA prepared with a mass ratio of 2:8 between coarse particles(75-106 μm) and fine particles(≤25 μm)yielded optimal results,with a strength of 491.95 MPa and elongation of 19.64%.This strength value represents an~41% increase compared with the sample that displayed a fine single microstructure(347.08 MPa for yield strength).The strength enhancement was attributed to the prevention of plastic deformation initiation from the fine particles during *** innovative approach to the creation of HEAs with bimodal structures shows promise for various applications,such as structural components that require a combination of high strength and high ductility.

关键词： High-entropy alloys CrCoFeMoNi Bimodal Gas atomization Mechanical properties

Hepatothorax due to a right diaphragmatic rupture related to duodenal ulcer perforation

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World Journal of Gastroenterology 2012年第39期18卷 5649-5652页

作者： Se-Jin Baek Jin Kim sung-ho lee Department of Surgery Korea University Anam HospitalSeoul 136-705South Korea Department of Thoracic Surgery Korea University Anam HospitalSeoul 136-705South Korea

Here, we present the case of a 53-year-old man with a hepatothorax due to a right diaphragmatic rupture related to duodenal ulcer perforation. On admission, the patient complained of severe acute abdominal pain, with physical examination findings suspicious for a perforated peptic ulcer. Of note, the patient had no history of other medical conditions or recent trauma, and the initial chest radiography and laboratory findings were not specific. A subsequent abdominal computed tomography revealed intrathoracic displacement of the liver, gallbladder, transverse colon and omentum through a right diaphragmatic defect. The patient then underwent an explorative laparotomy that confirmed duodenal ulcer perforation. A primary repair of the duodenal perforation was performed, and the diaphrag-matic defect was repaired using a polytetrafluoroeth-ylene patch after the organs were reduced and the cavity irrigated. This particular case proves interesting as right-sided spontaneous diaphragmatic ruptures are very rare and difficult to diagnose. Additionally, the best treatment for such large diaphragmatic defects is still controversial, especially in cases of intrathoracic or intra-abdominal contamination.

关键词： Diaphragmatic rupture Hepatothorax Du-odenal ulcer perforation Polytetrafluoroethylene mesh

Recombinant human fibroblast growth factor-2 promotes nerve regeneration and functional recovery after mental nerve crush injury

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Neural Regeneration Research 2017年第4期12卷 629-636页

作者： sung ho lee Wei-Peng Jin Na Ri Seo Kang-Mi Pang Bongju Kim Soung-Min Kim Jong-ho lee Dental Research Institute Department of Oral and Maxillofacial Surgery Seoul National University School of Dentistry Seoul Korea Dental Life Science Research Institute Clinical Translational Research Center for Dental Science Seoul National University Dental Hospital Seoul Korea Dental Research Institute Seoul National University Seoul Korea

Several studies have shown that fibroblast growth factor-2 （FGF2） can directly affect axon regeneration after peripheral nerve damage. In this study, we performed sensory tests and histological analyses to study the effect of recombinant human FGF-2 （rhFGF2） treatment on damaged mental nerves. The mental nerves of 6-week-old male Sprague-Dawley rats were crush-injured for 1 minute and then treated with 10 or 50 μg/mL rhFGF2 or PBS in crush injury area with a mini Osmotic pump. Sensory test using von Frey filaments at 1 week revealed the presence of sensory degeneration based on decreased gap score and increased difference score. however, at 2 weeks, the gap score and difference score were significantly rebounded in the mental nerve crush group treated with 10 μg/mL rhFGF2. Interestingly, treatment with 10 μg/mL rhFGF had a more obviously positive effect on the gap score than treatment with 50 μg/mL rhFGF2. In addition, retrograde neuronal tracing with Dil revealed a significant increase in nerve regeneration in the trigeminal ganglion at 2 and 4 weeks in the rhFGF2 groups （10 μg/mL and 50 μg/mL） than in the PBS group. The 10 μg/mL rhFGF2 group also showed an obviously robust regeneration in axon density in the mental nerve at 4 weeks. Our results demonstrate that 10 μg/mL rhFGF induces mental nerve regeneration and sensory recovery after mental nerve crush injury.

关键词： nerve regeneration mental nerve fibroblast growth factor crush injury sensory neuron functionalrecovery neural regeneration

Evidence for novel age-dependent network structures as a putative primo vascular network in the dura mater of the rat brain

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Neural Regeneration Research 2015年第7期10卷 1101-1106页

作者： ho-sung lee Dai-In Kang Seung Zhoo Yoon Yeon Hee Ryu Inhyung lee hoon-Gi Kim Byung-Cheon lee Ki Bog lee Ki Primo Research Laboratory Division of Electrical Engineering KAIST Institute for Information Technology Convergence Korea Advanced Institute of Science and Technology (KAIST) Nadi Primo Research Institute Graduate School of Integrative Medicine Sun Moon University Pharmacopuncture Medical Research Center Korean Pharmacopuncture Institute Department of Anesthesiology and Pain Medicine College of Medicine Korea University Acupuncture Moxibustion & Meridian Research Group Medical Research Division Korea Institute of Oriental Medicine Department of Veterinary Surgery College of Veterinary Medicine Seoul National University Faculty of Liberal Education Seoul National University Korea Atomic Energy Research Institute

With chromium-hematoxylin staining, we found evidence for the existence of novel age-dependent network structures in the dura mater of rat brains. Under stereomicroscopy, we noticed that chromium-hematoxylin-stained threadlike structures, which were barely observable in 1-weekold rats, were networked in specific areas of the brain, for example, the lateral lobes and the cerebella, in 4-week-old rats. In 7-week-old rats, those structures were found to have become larger and better networked. With phase contrast microscopy, we found that in 1-week-old rats, chromium-hematoxylin-stained granules were scattered in the same areas of the brain in which the network structures would later be observed in the 4- and 7-week-old rats. Such age-dependent network structures were examined by using optical and transmission electron microscopy, and the following results were obtained. The scattered granules fused into networks with increasing age. Cross-sections of the age-dependent network structures demonstrated heavily-stained basophilic substructures. Transmission electron microscopy revealed the basophilic substructures to be clusters with high electron densities consisting of nanosized particles. We report these data as evidence for the existence of age-dependent network structures in the dura mater, we discuss their putative functions of age-dependent network structures beyond the general concept of the dura mater as a supporting matrix.

关键词： nerve regeneration dura mater chromium-hematoxylin staining fascia primo vascular system brain hormone neural regeneration

Revealing the influence of in-situ formed LiCl on garnet/Li interface for dendrite-free solid-state batteries

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Journal of Energy Chemistry 2024年第5期92卷 394-403页

作者： Seoyoon Shin Jinuk lee Tae ho Shin Seokhee lee Hydrogen Energy Materials Center Korea Institute of Ceramic Engineering&TechnologyJinju-siGyeongsangnam-do 52851Republic of Korea Department of Materials Science and Engineering Yonsei UniversitySeoul 03722Republic of Korea

Inadequate interfacial contact between lithium and solid-state electrolytes(SSEs)leads to elevated impedance and the growth of lithium dendrites,presenting significant obstacles to the practical viability of solid-state batteries(SSBs).To ameliorate interfacial contact,optimizing the surface treatment of SSEs has been widely ***,the formation of LiCl through acid treatment,an equally crucial factor impacting SSB performance,has received limited attention,leaving its underlying mechanism *** study aims to shed light on SSE characteristics following LiCl formation and the removal of Li_(2)CO_(3) through acid *** seek to establish quantifiable links between SSE surface structure and SSB performance,focusing on interfacial resistance,current distribution,critical current density(CCD),and lithium *** formation of LiCl,occurring as Li_(2)CO_(3) is removed through acid treatment,effectively mitigates lithium dendrite formation on SSE *** action inhibits electron injection and reduces the diffusion rate of Li ***,acid treatment transforms the SSE surface into a lithiophilic state by eliminating surface Li_(2)CO_(3).Consequently,the interfacial resistance between lithium and SSEs substantially decreases from 487.67 to 35.99Ωcm^(2) at 25°*** leads to a notably high CCD of 1.3 mA cm^(-2) and a significantly extended cycle life of 1,000 ***,in full SSBs incorporating LiCoO_(2)cathodes and acid-treated garnet SSEs,we observe exceptional cyclability and rate *** findings highlight that acid treatment not only establishes a fundamental relationship between SSE surfaces and battery performance but also offers an effective strategy for addressing interfacial challenges in SSBs.

关键词： Solid-statebatteries Acidtreatment Interfacial stability LiCl Surface modification

Unraveling the Harmonious Coexistence of Ruthenium States on a Self-Standing Electrode for Enhanced Hydrogen Evolution Reaction

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ENERGY & ENVIRONMENTAL MATERIALS 2024年第6期7卷 303-311页

作者： Ma, Joonhee Cho, Jin Hyuk lee, Chaehyeon Kang, Moon sung Choi, sungkyun Jang, ho Won Ahn, Sang Hyun Back, Seoin Kim, Soo Young Korea Univ Dept Mat Sci & Engn Seoul 02841 South Korea Sogang Univ Inst Emergent Mat Dept Chem & Biomol Engn Seoul 04107 South Korea Pusan Natl Univ Coll Nanosci & Nanotechnol Dept Cogno Mechatron Engn Busan 46241 South Korea Seoul Natl Univ Res Inst Adv Mat Dept Mat Sci & Engn Seoul 08826 South Korea Chung Ang Univ Sch Chem Engn & Mat Sci Seoul 06974 South Korea

The development of cost-effective, highly efficient, and durable electrocatalysts has been a paramount pursuit for advancing the hydrogen evolution reaction (HER). Herein, a simplified synthesis protocol was designed to achieve a self-standing electrode, composed of activated carbon paper embedded with Ru single-atom catalysts and Ru nanoclusters (ACP/RuSAC+C) via acid activation, immersion, and high-temperature pyrolysis. Ab initio molecular dynamics (AIMD) calculations are employed to gain a more profound understanding of the impact of acid activation on carbon paper. Furthermore, the coexistence states of the Ru atoms are confirmed via aberration-corrected scanning transmission electron microscopy (AC-STEM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). Experimental measurements and theoretical calculations reveal that introducing a Ru single-atom site adjacent to the Ru nanoclusters induces a synergistic effect, tuning the electronic structure and thereby significantly enhancing their catalytic performance. Notably, the ACP/RuSAC+C exhibits a remarkable turnover frequency (TOF) of 18 s-1 and an exceptional mass activity (MA) of 2.2 A mg-1, surpassing the performance of conventional Pt electrodes. The self-standing electrode, featuring harmoniously coexisting Ru states, stands out as a prospective choice for advancing HER catalysts, enhancing energy efficiency, productivity, and selectivity. A self-standing electrode with the coexistence of Ru single atoms and Ru nanoclusters is designed for the hydrogen evolution reaction (HER). Additional acid activation process induces defects, anchoring more Ru ions on the substrate. Detailed experimental and computational investigations suggest that the electronic coupling effect between different Ru states significantly enhanced the overall HER performance. image

关键词： electrocatalysis electronic coupling effect hydrogen evolution reaction self-standing electrode CARBON ELECTROREDUCTION CATALYSTS PAPER