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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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Effect of gadolinium incorporation on optical characteristics of YNbO_4:Eu^(3+) phosphors for lamp applications

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Journal of Rare Earths 2012年第3期30卷 205-209页

作者： Sung Hwan Choi G. Anoop dong Wook Suh Kyung Pil Kim Hyun Ju lee jae Soo Yoo Display Materials Laboratory School of Chemical Engineering and Materials Science Chung-Ang University

Eu3＋-doped （Y,Gd）NbO4 phosphor was synthesized by solid-state reaction for possible application in cold cathode fluorescent lamps. A broad absorption band with peak maximum at 272 nm was observed which was due to the charge transfer between Eu3＋ ions and neighboring oxygen anions. A deep red emission at the peak wavelength of 612 nm was observed which could be attributed to the 5D0→7F2 transition in Eu3＋ ions. The highest luminance for Y1-x-yGdyNbO4：Eux3＋ under 254 nm excitation was achieved at Eu3＋ concentration of 18 mol.% （x=0.18） and Gd3＋ concentration of 8.2 mol.% （y=0.082）. The luminance of Y0.738Gd0.082NbO4：Eu3＋0.18 was higher than that of a typical commercial phosphor Y2O3：Eu3＋ and the CIE chromaticity coordinate was （0.6490, 0.3506）, which was deeper than that of Y2O3：Eu3＋. The particle size of the synthesized phosphors was controlled by the NaCl flux and particle size as high as 8 μm with uniform size distribution of particles was obtained.

关键词： YNbO4:Eu oxide phosphors rare earths

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Optimization of post-warranty sequential inspection for second-hand products

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Journal of Systems Engineering and Electronics 2017年第4期28卷 793-800页

作者： Dae-Kyung Kim jae-Hak Lim dong Ho Park Department of Statistics Chonbuk National University Department of Management & Accounting Hanbat National University Industry Academic Cooperation Foundation Hallym University

This paper considers an optimal sequential inspection schedule for a second-hand product after that the free nonrenewable warranty is expired. The length of warranty is prespecified and during the warranty period, the product is minimally repaired by the dealer when it fails. Following the expiration of the non-renewing warranty, the product is inspected and upgraded sequentially a fixed number of times at the expenses of the *** each inspection, the failure rate of the product is reduced proportionally so that the product is upgraded. The product is assumed to deteriorate as it ages and the replacement of the product occurs when a fixed number of inspections are rendered. In addition,the intervals between two successive inspections are assumed to decrease monotonically. The main objective of this paper is to determine the optimal improvement level to upgrade the product at each inspection so that the expected maintenance cost during the life cycle of the product is minimized from the perspective of the customer. Under the given cost structures, we derive an explicit formula to obtain the expected maintenance cost incurred during the life cycle of the product and discuss the method to find the optimal level of the improvement analytically in case the failure times follow the Weibull distribution. Numerical results are analyzed to observe the impact of relevant parameters on the optimal solution.

关键词： second-hand product sequential inspection upgrade action life cycle of the product expected maintenance cost free non-renewable warranty

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Tailoring uniform γ-MnO2 nanosheets on highly conductive three-dimensional current collectors for high-performance supercapacitor electrodes

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Nano Research 2015年第3期8卷 990-1004页

作者： Sangbaek Park Hyun-Woo Shim Chan Woo lee Hee Jo Song Ik jae Park jae-Chan Kim Kug Sun Hong dong-Wan Kim Department of Materials Science and Engineering Seoul National University Seou1151-744 R. O. Korea School of Civil Environmental and Architectural Engineering Korea University Seou1136-713 R. O. Korea

Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the design and synthesis of size- and thickness-tunable two-dimensional （2-D） MnO2 nanosheets on highly conductive one-dimensional （l-D） backbone arrays has been developed via a facile, one-step enhanced chemical bath deposition （ECBD） method at a low temperature （-50 ℃）. Inclusion of an oxidizing agent, BrO3-, in the solution was crucial in controlling the heterogeneous nucleation and growth of the nanosheets, and in inducing the formation of the tailored and uniformly arranged nanosheet arrays. We fabricated supercapacitor devices based on 3-D MnO2 nanosheets with conductive Sb-doped SnO2 nanobelts as the backbone. They achieved a specific capacitance of 162 F·g-1 at an extremely high current density of 20 A·g% and good cycling stability that shows a capacitance retention of -92% of its initial value, along with a coulombic efficiency of almost 100% after 5,000 cycles in an aqueous solution of I M Na2SO4. The results were attributed to the unique hierarchical structures, which provided a short diffusion path of electrolyte ions by means of the 2-D sheets and direct electrical connections to the current collector by 1-D arrays as well as the prevention of aggregation by virtue of the well-aligned 3-D structure.

关键词： nanosheets manganese oxide chemical bath deposition SnO2 nanobelts supercapacitor

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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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Nasal cavity fungus ball discovered accidentally:A case report

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World Journal of Clinical Cases 2025年第5期13卷 44-48页

作者： Dae-Neung lee dong Hoon lee Sang Chul Lim Department of Otolaryngology-Head and Neck Surgery Chonnam National University Medical SchoolChonnam National University Hwasun HospitalHwasun 58128South Korea Department of Otolaryngology-Head and Neck Surgery Chonnam National University Medical SchoolHwasun HospitalChonnam National University Hwasun HospitalHwasun 58128South Korea Department of Otolaryngology-Head and Neck Surgery Chonnam National University Medical SchoolKwangju 501190South Korea

BACKGROUND Fungal balls within the nasal cavity are an exceedingly rare clinical entity,typically presenting with nonspecific symptoms or being identified *** SUMMARY This report presents an incidental discovery of a fungal ball in the nasal cavity during routine imaging,with no associated clinical *** This case underscores the importance of considering the possibility of asympto-matic presentations of nasal fungal balls,which may be detected incidentally during imaging evaluations.

关键词： Fungi Mycoses Fungus ball Nasal cavity Nasal surgical procedures Case report

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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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Butein effects in colitis and interleukin-6/signal transducer and activator of transcription 3 expression

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World Journal of Gastroenterology 2015年第2期21卷 465-474页

作者： Sehe dong lee Jung Wan Choe Beom jae lee Myoung Hee Kang Moon Kyung Joo Ji Hoon Kim Jong Eun Yeon Jong-jae Park jae Seon Kim Young-Tae Bak Division of Gastroenterology Department of Internal MedicineKorea University Medical CenterSeoul 152-703South Korea

AIM: To evaluate the effects of butein on inflammatory cytokines, matrix metalloproteinase-9(MMP-9), andcolitis in interleukin(IL)-10-/- ***: To synchronize colitis, 8- to 10-wk-old IL-10-/- mice were fed pellet-chow containing piroxicam for 2 wk. Subsequently, phosphate-buffered saline or butein(1 mg/kg per day, ip) was injected for 4 wk. Histologic scores, inflammatory cytokines, MMP-9 and phosphorylated signal transducer and activator of transcription 3(p STAT3) expressions were analyzed in IL-10-/- mice and in Colo 205 ***: Butein reduced the colonic inflammatory score by > 50%. Expression levels of IL-6, IL-1β, interferon(IFN)-γ and MMP-9 were decreased in the colons of mice exposed to butein, whereas other inflammatory cytokines(IL-17 A, IL-21 and IL-22) were unchanged. Immunohistochemical staining for p STAT3 and MMP-9 was significantly decreased in the buteintreated groups compared with the controls. Butein inhibited IL-6-induced activation of STAT3 in Colo 205 ***: Butein ameliorated colitis in IL-10-/-mice by regulating IL-6/STAT3 and MMP-9 activation.

关键词： Butein Interleukin-6/signal transducer and activat

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