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Remote induction of in situ hydrogelation in a deep tissue,using an alternating magnetic field and superparamagnetic nanoparticles

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Nano Research 2018年第11期11卷 5997-6009页

作者： Hwangjae lee Guru Karthikeyan Thirunavukkarasu Semin Kim jae Young lee School of Materials Science and Engineering Gwangju Institute of Science and Technology Gwongju 51005 Republic of Korea Department of Biomedical Science and Engineering Gwangju Institute of Science and Technology Gwangju 61005 Repubfic of Korea

In situ hydrogelation systems, such as transdermal polymerization, allow for external control over the gelation processes in a minimally invasive way. Recently, a novel system consisting of near-infrared (NIR) light and plasmonic nanomaterials was demonstrated to cause in vivo transdermal gelation. However, NIR light is not sufficient for gelation induction in deep tissues owing to its limited penetration into tissues. To overcome this problem, here we developed an alternating magnetic field (AMF)-inducible hydrogelation system with superparamagnetic iron oxide nanoparticles (SPIONs), by which a deep-tissue-penetrating AMF can induce heat generation in the SPIONs and temperature elevation ( 43 degrees C), leading to initiation of thermal polymerization of poly(ethylene glycol) diacrylate. The feasibility of our AMF-inducible hydrogelation was successfully demonstrated using thick porcine muscle tissues (> 2 cm), whereas the NIR light-based hydrogelation system could induce gelation only in tissues thinner than several millimeters. Cell viability assays indicated cytocompatibility of the AMF-inducible hydrogelation for cell encapsulation and delivery. In vivo hydrogelation in rat muscle tissues further validated in situ hydrogelation in deep muscle tissues of a living animal. This AMF-inducible hydrogelation system may overcome the conventional problems of depth limitation and should extend the applicable area of on-demand injectable hydrogel systems for tissue engineering and drug delivery applications.

关键词： hydrogelation alternating magnetic field superparamagnetic nanoparticles hydrogel tissue engineering cell delivery

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Drug Transport Microdevice Mimicking an Idealized Nanoscale Bio-molecular Motor

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Journal of Bionic Engineering 2011年第4期8卷 455-463页

作者： jae Hwan lee Ramana M. Pidaparti Department of Mechanical Engineering Virginia Commonwealth University Richmond VA 23284 USA

Molecular motors are nature＇s nano-devices and the essential agents of movement that are an integral part of many living organisms. The supramolecular motor, called Nuclear Pore Complex （NPC）, controls the transport of all cellular material be- tween the cytoplasm and the nucleus that occurs naturally in biological cells of many organisms. In order to understand the design characteristics of the NPC, we developed a microdevice for drug/fluidic transport mimicking the coarse-grained repre- sentation of the NPC geometry through computational fluid dynamic analysis and optimization. Specifically, the role of the central plug in active fluidic/particle transport and passive transport （without central plug） was investigated. Results of flow rate, pressure and velocity profiles obtained from the models indicate that the central plug plays a major role in transport through this biomolecular machine. The results ofthis investigation show that fluidic transport and flow passages are important factors in designing NPC based nano- and micro-devices for drug delivery.

关键词： molecular motors nuclear pore complex geometry design simulation

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Porous Microspheres Comprising CoSe2 Nanorods Coated with N-Doped Graphitic C and Polydopamine-Derived C as Anodes for Long-Lived Na-Ion Batteries

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Nano-Micro Letters 2022年第7期14卷 118-139页

作者： jae Seob lee Rakesh Saroha Jung Sang Cho Department of Engineering Chemistry Chungbuk National UniversityCheongjuChungbuk 361-763Republic of Korea

Metal–organic framework-templated nitrogen-doped graphitic carbon(NGC)and polydopaminederived carbon(PDA-derived C)-double coated one-dimensional CoSe_(2) nanorods supported highly porous threedimensional microspheres are introduced as anodes for excellent Na-ion batteries,particularly with long-lived cycle under carbonate-based electrolyte *** microspheres uniformly composed of ZIF-67 polyhedrons and polystyrene nanobeads(φ=40 nm)are synthesized using the facile spray pyrolysis technique,followed by the selenization process(P-CoSe_(2)@NGC NR).Further,the PDA-derived C-coated microspheres are obtained using a solution-based coating approach and the subsequent carbonization process(P-CoSe_(2)@PDA-C NR).The rational synthesis approach benefited from the synergistic effects of dual carbon coating,resulting in a highly conductive and porous nanostructure that could facilitate rapid diffusion of charge species along with efficient electrolyte infiltration and effectively channelize the volume ***,the prepared nanostructure exhibits extraordinary electrochemical performance,particularly the ultra-long cycle life *** instance,the advanced anode has a discharge capacity of 291(1000th cycle,average capacity decay of 0.017%)and 142 mAh g^(-1)(5000th cycle,average capacity decay of 0.011%)at a current density of 0.5 and 2.0 A g^(-1),respectively.

关键词： Spray pyrolysis Sodium-ion batteries Cobalt selenide nanorods Porous microspheres Dual carbon coating

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Observation on bus voltage angles through power flow computation for 2010 summer peak of South Korea

Observation on bus voltage angles through power flow computa...

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2011 International Conference on Advanced Power System Automation and Protection(APAP 2011)

作者： lee SangJoong lee woon-Hee Seoul National University of Science and Technology Seoul 139-743 South Korea KPX(Korea Power Exchange) Seoul South Korea

ISBN: (纸本)9781424496228

In this paper, some results of power flow computation for 2010 summer peak of South Korea are presented following introduction of the Korea power network composed of 154kV, 345kV and 765kV transmission lines. They include: total MW on 2010 summer peak time MW demands of major load buses MW outputs of major generators bus voltages of significant buses. Bus angles and the angle differences between buses are important for the study of power flow, stability, protective relaying, etc. This paper shows the magnitude of voltage angles for some meaningful buses. Magnitudes of the real and imaginary part of the complex voltage angles of the buses are compared. The spread angle of the network is also observed.

关键词： bus voltage angle power flow computation summer peak

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Secondary craniofacial necrotizing fasciitis from a distant septic emboli: A case report

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World Journal of Clinical Cases 2022年第31期10卷 11630-11637页

作者： Da-woon lee Si-Hyun Kwak Hwan-Jun Choi Department of Plastic and Reconstructive Surgery College of MedicineSoonchunhyang UniversityCheonan-si 31151South Korea Institute of Tissue Regeneration College of MedicineSoonchunhyang UniversityCheonan-si 31151South Korea

BACKGROUND Craniofacial necrotizing fasciitis(CNF)is an uncommon but fatal infection that can spread rapidly through the subfascial planes in the head and neck *** usually progress rapidly,and early management is necessary to optimize *** SUMMARY A 43-year-old man visited our hospital with left hemifacial swelling involving the buccal and submandibular *** patient had fever for approximately 10 d before visiting the hospital,but did not report any other systemic *** tomography scan demonstrated an abscess with gas *** surgical drainage of the facial abscess,the patient’s systemic condition worsened and progressed to septic *** examination revealed pulmonary and renal *** percutaneous catheter drainage was performed at the renal abscess site,which caused improvement of *** patient showed no evidence of systemic complications during the 4-mo post-operative follow-up *** As the patient did not improve with conventional CNF treatment and symptoms only resolved after controlling the infection,the final diagnosis was secondary CNF with septic *** surgical decompression is important for CNF ***,if symptoms worsen despite early diagnosis and management,such as pus drainage and surgical intervention,clinicians should consider the possibility of a secondary abscess from internal organs.

关键词： Craniofacial necrotizing fasciitis Septic emboli Klebsiella pneumoniae Secondary Case report

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EXPERIMENTAL ESTIMATION OF A SCALING EXPONENT FOR TIP VORTEX CAVITATION VIA ITS INCEPTION TEST IN FULL-AND MODEL-SHIP

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Journal of Hydrodynamics 2012年第5期24卷 658-667页

作者： lee Jeung-Hoon JUNG jae-Kwon lee Kyung-Jun HAN jae-Moon PARK Hyung-Gil SEO Jong-Soo Samsung Ship Model Basin(SSMB) Marine Research InstituteSamsung Heavy IndustriesScience TownDaejeon 305-380Korea

Tip vortex cavitation noise of marine propeller became primary concems to reduce hazardous environmental impacts from commercial ship or to keep the underwater surveillance of naval ships. The investigations of the tip vortex and its induced noise are normally conducted through the model test in a water cavitation tunnel. However the Reynolds number of model-test is much smaller than that of the full-scale, which subsequently results in the difference of tip vortex cavitation inception. Hence, the scaling law between model- and full-scales needs to be identified prior to the prediction and assessment of propeller noise in full scale. From previous researches, it is generally known that the incipient caivtation number of tip vortex can be represented as a power of the Reynolds number. However, the power exponent for scaling, which is the main focus of this research, has not been clearly studied yet. This paper deals with the estimation of scaling exponent based on tip vortex cavitation inception test in both full- and model-scale ships. Acoustical measurements as well as several kind of signal processing technique for an inception criterion suggest the scaling exponent as 0.30. The scaling value proposed in this study shows slight difference to the one of most recent research. Besides, extrapolation of model-ship noise measurement using the proposed one predicts the full-scale noise measurement with an acceptable discrepancy.

关键词： tip vortex cavitation underwater radiated noise scaling exponent

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Inverse relationship between bioavailable testosterone and subclinical coronary artery calcification in non-obese Korean men

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Asian Journal of Andrology 2012年第4期14卷 612-615页

作者： Byoung-Jin Park jae-Yong Shim Yong-jae lee Jung-Hyun lee Hye-Ree lee Department of Family Medicine Yonsei University College of Medicine Seou1135-720 Korea Department of Health Promotion Center Gangnam Severance Hospita Yonsei University College of Medicine Seou1135-720 Korea

Although low testosterone levels in men have been associated with high risk for cardiovascular disease, little is known about the association between male sex hormones and subclinical coronary disease in men with apparently low cardiometabolic risk. This study was performed to investigate the association between male sex hormones and subclinical coronary artery calcification measured as coronary calcium score in non-obese Korean men. We examined the relationship of total testosterone, sex hormone-binding globulin, bioavai lable testosterone and free testosterone with coronary calcium score in 291 non-obese Korean men （mean age： 52.8--- 9.3 years） not having a history of cardiovascular disease. Using multiple linear regression, we evaluated associations between log （sex hormone） levels and log （coronary calcium score） after adjusting for confounding variables in 105 men with some degree of coronary calcification defined as coronary calcium score ~〉 1. In multiple linear regression analysis, bioavailable testosterone was inversely associated with coronary calcium score （P=0.046） after adjusting for age, body mass index, smoking status, alcohol consumption, regular exercise, mean blood pressure, resting heart rate, C-reactive protein, fasting plasma glucose, total cholesterol, triglyceride, high-density lipoprotein （HDL） cholesterol, hypertension medication and hyperlipidernia medication, whereas total testosterone, sex hormone-binding globulin and free testosterone were not （P=0.674, P=O. 121 and P=O. 102, respectively）. Our findings indicate that bioavailable testosterone is inversely associated with the degree of subclinical coronary artery calcification in non-obese men.

关键词： bioavailable testosterone cardiovascular disease coronary calcium score male sex hormone subclinical coronary arterydisease testosterone

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Origin of superior low-cycle fatigue resistance of an interstitial metastable high-entropy alloy

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Journal of Materials Science & Technology 2022年第20期115卷 115-128页

作者： Seyed Amir Arsalan Shams jae Wung Bae jae Nam Kim Hyoung Seop Kim Taekyung lee Chong Soo lee Graduate Institute of Ferrous Technology Pohang University of Science and TechnologyPohang 37673Republic of Korea Department of Materials Science and Engineering Pohang University of Science and TechnologyPohang 37673Republic of Korea School of Mechanical Engineering Pusan National UniversityBusan 46241Republic of Korea

In this study, the deformation behaviors and related microstructural evolutions were investigated in either monotonic or cyclic deformation modes in an interstitial metastable high-entropy alloy. These investigations aimed to reveal the mechanisms underlying the superior low-cycle fatigue(LCF) life of this alloy.A thermomechanical process was applied to induce fine-grained(FG) and coarse-grained(CG) microstructures in Fe–30Mn–10Co–10Cr–0.4C(atomic percentage) alloy. Their superior combination of strength and ductility was attributed to the appearance of deformation-induced ε-martensite and the presence of carbon. The CG alloy showed a greater volume fraction of ε-martensite than the FG alloy in the monotonic deformation mode, and vice versa in the cyclic mode. Such a disparity was interpreted in light of the back-stress effect of the relaxed γ-grain boundaries in the latter mode. Meanwhile, the γ-to-ε phase transformation under cyclic loading at low strain amplitudes(0.4%) barely led to an improved fatigue life as compared with that at higher strain amplitudes(≥ 0.55%). The high reversibility of partial dislocation motions under cyclic loading and delaying the formation of dislocation cells through the martensitic transformation could explain why the alloys investigated in this study exhibited a superior LCF life compared with high-entropy alloys reported in previous studies.

关键词： High-entropy alloy Transformation-induced plasticity Monotonic deformation Cyclic deformation Low-cycle fatigue Stacking faults

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Development of Non-Dissipative Direct Time Integration Method for Structural Dynamics Application

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Computer Modeling in Engineering & Sciences 2019年第1期118卷 41-89页

作者： Sun-Beom Kwon jae-Myung lee Department of Naval Architecture and Ocean Engineering Pusan National UniversityJangjeon-DongGeumjeong-GuBusan 609-735Korea.

A direct time integration scheme based on Gauss-Legendre quadrature is proposed to solve problems in linear structural *** proposed method is a oneparameter non-dissipative *** stability,accuracy,and dispersion characteristics are achieved using appropriate values of the *** proposed scheme has second-order accuracy with and without physical ***,its stability,accuracy,and dispersion are *** addition,its performance is demonstrated by the two-dimensional scalar wave problem,the single-degree-of-freedom problem,two degrees-of-freedom spring system,and beam with boundary *** wave propagation problem is solved in the high frequency wave regime to demonstrate the advantage of the proposed *** the proposed scheme is applied to solve the wave problem,more accurate solutions than those of other methods are obtained by using the appropriate value of the *** the single-degree-offreedom system,two degrees-of-freedom system,and the time responses of beam,the proposed scheme can be used effectively owing to its high accuracy and lower computational cost.

关键词： Structural dynamics finite elements direct time integration Gauss-Legendre quadrature non-dissipative scheme.

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Flash‑Induced High‑Throughput Porous Graphene via Synergistic Photo‑Effects for Electromagnetic Interference Shielding

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Nano-Micro Letters 2023年第11期15卷 1-18页

作者： Jin Soo lee Jeong‑Wook Kim jae Hee lee Yong Koo Son Young Bin Kim Kyoohee Woo Chanhee lee Il‑Doo Kim jae Young Seok Jong Won Yu Jung Hwan Park Keon jae lee Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak‑roYuseong‑guDaejeon 34141Republic of Korea School of Electrical Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak‑roYuseong‑guDaejeon 34141Republic of Korea Department of Printed Electronics Nano‑Convergence Manufacturing Systems Research DivisionKorea Institute of Machinery and Materials(KIMM)156 Gajeongbuk‑RoYuseong‑GuDaejeon 34103Republic of Korea Department of Mechanical System Design Engineering Seoul National University of Science and Technology232 Gongneung‑roNowon‑guSeoul 01811Republic of Korea Department of Mechanical Engineering(Department of Aeronautics Mechanical and Electronic Convergence Engineering)Kumoh National Institute of Technology61 Daehak‑roGumiGyeongbuk 39177Republic of Korea

Porous 2D materials with high conductivity and large surface area have been proposed for potential electromagnetic interference(EMI)shielding materials in future mobility and wearable applications to prevent signal noise,transmission inaccuracy,system malfunction,and health ***,we report on the synthesis of lightweight and flexible flash-induced porous graphene(FPG)with excellent EMI shielding *** broad spectrum of pulsed flashlight induces photo-chemical and photo-thermal reactions in polyimide films,forming 5×10 cm^(2)-size porous graphene with a hollow pillar structure in a few *** resulting material demonstrated low density(0.0354 g cm^(−3))and outstanding absolute EMI shielding effectiveness of 1.12×10^(5) dB cm^(2) g^(−1).The FPG was characterized via thorough material analyses,and its mechanical durability and flexibility were confirmed by a bending cycle ***,the FPG was utilized in drone and wearable applications,showing effective EMI shielding performance for internal/external EMI in a drone radar system and reducing the specific absorption rate in the human body.

关键词： Porous graphene Flash lamp Photo-pyrolysis High-throughput Electromagnetic interference shielding

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