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Journal of Hydrodynamics 2011年第5期23卷 607-614页

作者： HONG Taehyup kim chang Nyung Department of Mechanical Engineering Graduate School Kyung Hee UniversityYongin Korea Department of Mechanical Engineering College of Engineering Kyung Hee University Yongin Korea

The effects of implantation angles of Bileaflet Mechanical Heart Valves （BMHVs） on the blood flow and the leaflet motion are investigated in this paper. The physiological blood flow interacting with the moving leaflets of a BMHV is simulated with a strongly coupled implicit Fluid-Structure Interaction （FSI） method based on the Arbitrary-Lagrangian-Eulerian （ALE） approach and the dynamic mesh method （remeshing） in Fluent. BMHVs are widely used to be implanted to replace the diseased heart valves, but the patients would suffer from some complications such as hemolysis, platelet activation, tissue overgrowth and device failure. These complications are closely related to both the flow characteristics near the valves and the leaflet dynamics. The current numerical model is validated against a previous experimental study. The numerical results show that as the rotation angle of BMHV is increased the degree of asymmetry of the blood flow and the leaflet motion is increased, which may lead to an unbalanced force acting on the BMHVs. This study shows the applicability of the FSI model for the interaction between the blood flow and the leaflet motion in BMHVs.

关键词： mechanical heart valve rotational implantation blood flow leaflet motion fluid-structure interaction

Effects of compressive stress on the nonlinear electromechanical behavior of ferroelectric ceramics

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Science China(Technological Sciences) 2006年第1期49卷 29-37页

作者： LEE jung-ju kim Hyun Cheol Department of Mechanical Engineering KAIST Taejon 305-701 Korea

The effects of compressive stress parallel and perpendicular to the polar axis of PZT ceramics on the nonlinear electromechanical behavior of the materials has been experimentally studied. A domain-switching model that divides each 180° switching to two successive 90° switching is proposed to explain these effects. In the case of stress parallel to the polar axis, domain switching in the ceramics is approximately axisymmetric and can be simulated by an analytical model. While in the case of stress perpendicular to the polar axis, domain switching is three-dimensional and cannot be simplified. The simulated re-sults that match the experiments well show the validity of the proposed domain-switching model.

关键词： ferroelectric ceramics, domain switching, electromechanical, PZT.

Pebbling numbers of some graphs

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Science China Mathematics 2002年第4期45卷 470-478页

作者：冯荣权 ju Young kim School of Mathematical Sciences Peking University Beijing 100871 China Department of Mathematics Catholic University of Daegu Kyongsan 713-702 Korea

Chung defined a pebbling move on a graphG as the removal of two pebbles from one vertex and the addition of one pebble to an adjacent vertex. The pebbling number of a connected graphG, f(G), is the leastn such that any distribution ofn pebbles onG allows one pebble to be moved to any specified but arbitrary vertex by a sequence of pebbling moves. Graham conjectured that for any connected graphsG andH, f(G xH) ≤ f(G)f(H). In the present paper the pebbling numbers of the product of two fan graphs and the product of two wheel graphs are computed. As a corollary, Graham’s conjecture holds whenG andH are fan graphs or wheel graphs.

关键词： pebbling, Graham's conjecture, Cartesian product, fan graph, wheel graph.

cAMP/PKA pathway and mitochondrial protection in oxidative stress-induced optic nerve head astrocytes

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Neural Regeneration Research 2021年第1期16卷 108-109页

作者： Keun-Young kim Won-Kyu ju National Center for Microscopy and Imaging Research and Department of Neurosciences University of California San DiegoLa JollaCAUSA Hamilton Glaucoma Center and Shiley Eye Institute The Viterbi Family Department of OphthalmologyUniversity of California San DiegoLa JollaCAUSA

Oxidative stress and cyclic adenosine 3′,5′-monophosphate(cAMP)/protein kinase A(PKA)pathway in the optic nerve head astrocytes:Glaucoma is a leading cause of blindness worldwide in individuals 60 years of age and *** the widely appreciated disease relevance of structural and functional abnormalities of astrocyte in the optic nerve head(ONH)that is associated with retinal ganglion cell(RGC)axon degeneration,the molecular mechanisms underlying astrocyte dysfunction in glaucomatous ONH degeneration are poorly *** stress is strongly linked to glaucoma pathogenesis,and astrocytes are the responsible cell type that is mostly related to oxidative stress and glaucomatous ONH degeneration.

关键词： oxidative stress degeneration

The extract of Celtis choseniana Nakai alleviates testosterone-in-duced benign prostatic hyperplasia through inhibiting 5αreductase type 2 and the Akt/NF-κB/AR pathway

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Chinese Journal of Natural Medicines 2022年第7期20卷 518-526页

作者： HONG Geum-Lan kim Tae-Won LEE Hui-ju kim Yae-Ji kim Kyung-Hyun juNG ju-Young Department of Veterinary Medicine&Institute of Veterinary Science Chungnam National UniversityDaejeon 34134Republic of Korea

Benign prostatic hyperplasia(BPH)is a chronic male disease characterized by the enlarged *** choseniana Nakai(***)is medicinally used to alleviate pain,gastric disease,and lung *** this study,the effect of *** extract on BPH was investigated using testosterone-induced *** Dawley rats were divided into five groups:control,BPH(testosterone 5 mg·kg^(−1)),Fina(finasteride 2 mg·kg^(−1)),and ***(50 and 100 mg·kg^(−1)).After four weeks of TP treatment with finasteride or ***,prostate weights and DHT levels were *** addition,the prostates were histopathologically examined and measured for protein kinase B(Akt)/nuclear factor-κB(NF-κB)/AR signaling,proliferation,apoptosis,and ***-state weight and epithelial thickness were reduced in the *** groups compared with that in the BPH *** extract of *** acted as a 5αreductase inhibitor,reducing DHT levels in the ***,the extract of *** blocked the activation of p-Akt,nuclear NF-κB activation and reduced the expression of AR and PSA compared with ***,the ex-pression of Bax,PARP-1,and p53 increased,while the expression of bcl-2 *** present study demonstrated that ***-ana extract alleviated testosterone-induced BPH by suppressing 5αreductase and Akt/NF-κB activation,reducing AR signaling and in-ducing apoptosis and autophagy in the *** results suggested that *** probably contain potential herbal agents to alleviate BPH.

关键词： Apoptosis Androgen receptor Benign prostate hyperplasia Celtis choseniana Nakai 5α-Reductase type 2 NF-κB

Crawling of effector T cells on extracellular matrix： role of integrins in interstitial migration in inflamed tissues

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Cellular & Molecular Immunology 2014年第1期11卷 1-4页

作者： chang H kim Laboratory of Immunology and Hematopoiesis Department of Comparative Pathobiology Weldon School of Biomedical Engineering Purdue Center for Cancer Research PurdueUniversity West Lafayette IN 47907 USA

Tcells are one of the most migratory cells in the body. The development and function of T cells depend on their interaction with other cells, which is, in turn, dependent on optimal cell migra- tion. T cells migrate largely in three dif- ferent ways： rapid distribution via blood vessels through hemodynamic move- ment, transendothelial migration and interstitial movement. Transendothelial migration involves sequential activation of selectins, chemokine receptors and integrin molecules expressed by migrat- ing T cells, leading to extravasation from blood vessel into local tissue environ- ments.

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Microbiota or short-chain fatty acids: which regulates diabetes?

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Cellular & Molecular Immunology 2018年第2期15卷 88-91页

作者： chang H kim Department of Comparative Pathobiology and Biological Sciences Laboratory of Immunology and HematopoiesisWeldon School of Biomedical EngineeringPurdue Institute of InflammationImmunology and Infectious DiseasesPurdue Center for Cancer ResearchPurdue UniversityWest Lafayette47907INUSA

Diabetes mellitus,with sustained high-sugar levels in the blood,has been steadily rising in prevalence *** 12–14%of the US population has been diagnosed with diabetes in recent years.1 One major reason for the rise of diabetes is dietary *** consumption of processed carbohydrates with inadequate consumption of dietary fiber(DF)has been recognized as a major risk factor for diabetes,as hypothesized several decades ago by Trowell.

关键词： diabetes sustained dietary

Gallbladder Removal Simulation for Laparoscopic Surgery Training: A Hybrid Modeling Method

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Journal of Computer Science & Technology 2013年第3期28卷 499-507页

作者： Youngjun kim Dongjune chang jungsik kim Sehyung Park Center for Bionics Korea Institute of Science and Technology Department of Mechanical Engineering Korea Advanced Institute of Science and Technology

Laparoscopic surgery has many advantages, but it is difficult for a surgeon to achieve the necessary surgical skills. Recently, virtual training simulations have been gaining interest because they can provide a safe and efficient learning environment for medical students and novice surgeons. In this paper, we present a hybrid modeling method for simulating gallbladder removal that uses both the boundary element method （BEM） and the finite element method （FEM）. Each modeling method is applied according to the deformable properties of human organs： BEM for the liver and FEM for the gallbladder. Connective tissues between the liver and the gallbladder are also included in the surgical simulation. Deformations in the liver and the gallbladder models are transferred via connective tissue springs using a mass-spring method. Special effects and techniques are developed to achieve realistic simulations, and the software is integrated into a custom-designed haptic interface device. Various computer graphical techniques are also applied in the virtual gallbladder removal laparoscopic surgery training. The detailed techniques and the results of the simulations are described in this paper.

关键词： deformable body modeling gallbladder removal laparoscopic surgery training simulation

Design of an Information Security Service for Medical Artificial Intelligence

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Computers, Materials & Continua 2022年第1期70卷 679-694页

作者： Yanghoon kim Jawon kim Hangbae chang Department of Cyber Drone Bot Military Engineering Shinhan UniversityUijeongbu-si11644Gyeonggi-doKorea Department of Security Convergence Graduate SchoolChung-Ang UniversityDongjack-gu06974SeoulKorea Department of Industrial Security Chung-Ang UniversityDongjak-gu06974SeoulKorea

The medical convergence industry has gradually adopted ICT devices,which has led to legacy security problems related to ICT ***,it has been difficult to solve these problems due to data resource *** problems can cause a lack of reliability in medical artificial intelligence services that utilize medical ***,to provide reliable services focused on security internalization,it is necessary to establish a medical convergence environment-oriented security management *** study proposes the use of system identification and countermeasures to secure systemreliabilitywhen using medical convergence environment information in medical artificial *** checked the life cycle of medical information and the flow and location of information,analyzed the security threats that may arise during the life cycle,and proposed technical countermeasures to overcome such *** verified the proposed countermeasures through a survey of *** requirements were defined based on the information life cycle in the medical convergence *** also designed technical countermeasures for use in the security management systems of hospitals of diverse sizes.

关键词： Medical artificial intelligence medical information security convergence environment

Protein Arginine Methyltransferase 1 Ablation in Motor Neurons Causes Mitochondrial Dysfunction Leading to Age-related Motor Neuron Degeneration with Muscle Loss

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Research 2024年第1期2023卷 637-649页

作者： Hyun-Kyung So Hyebeen kim Jinwoo Lee chang-Lim You Chae-Eun Yun Hyeon-ju Jeong Eun-ju Jin Yunju Jo Dongryeol Ryu Gyu-Un Bae Jong-Sun Kang Department of Molecular Cell Biology Sungkyunkwan University School of MedicineSuwonKorea Single Cell Network Research Center Sungkyunkwan University School of MedicineSuwonKorea Research Institute of Aging-Related Diseases AniMusCureInc.SuwonKorea Drug Information Research Institute Muscle Physiome Research CenterCollege of PharmacySookmyung Women’s UniversitySeoulKorea

Neuromuscular dysfunction is tightly associated with muscle wasting that occurs with age or due to degenerative ***,the molecular mechanisms underlying neuromuscular dysfunction are currently *** studies have proposed important roles of Protein arginine methyltransferase 1(Prmt1)in muscle stem cell function and muscle *** the current study,we set out to determine the role of Prmt1 in neuromuscular function by generating mice with motor neuron-specific ablation of Prmt1(mnKO)using *** exhibited age-related motor neuron degeneration and neuromuscular dysfunction leading to premature muscle loss and ***1 deficiency also impaired motor function recovery and muscle reinnervation after sciatic nerve *** transcriptome analysis of aged mnKO lumbar spinal cords revealed alterations in genes related to inflammation,cell death,oxidative stress,and ***,mnKO lumbar spinal cords of sciatic nerve injury model or aged mice exhibited elevated cellular stress response in motor ***,Prmt1 inhibition in motor neurons elicited mitochondrial *** findings demonstrate that Prmt1 ablation in motor neurons causes agerelated motor neuron degeneration attributing to muscle ***,Prmt1 is a potential target for the prevention or intervention of sarcopenia and neuromuscular dysfunction related to aging.

关键词： degeneration impaired prevention