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Changes in brain activation patterns according to cross-training effect in serial reaction time task An functional MRI study

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Neural Regeneration Research 2013年第7期8卷 639-646页

作者： Yong hyun Kwon Jung Won Kwon ji Won Park Department of Physical Therapy Yeungnam College of Science & Technology Department of Physical Therapy College of Health Science Catholic University of Daegu

Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral limb. We used functional MRI to investigate whether motor performance of the untrained limb could be improved using a serial reaction time task according to motor sequential learning of the trained limb, and whether these skill acquisitions led to changes in brain activation patterns. We recruited 20 right-handed healthy subjects, who were randomly allocated into training and control groups. The training group was trained in performance of a serial reaction time task using their non-dominant left hand, 40 minutes per day, for 10 days, over a period of 2 weeks. The control group did not receive training. Measurements of response time and percentile of response accuracy were performed twice during pre- and post-training, while brain functional MRI was scanned during performance of the serial reaction time task using the untrained right hand. In the training group, prominent changes in response time and percentile of response accuracy were observed in both the untrained right hand and the trained left hand between pre- and post-training. The control group showed no significant changes in the untrained hand between pre- and post-training. In the training group, the activated volume of the cortical areas related to motor function （i.e., primary motor cortex, premotor area, posterior parietal cortex） showed a gradual decrease, and enhanced cerebellar activation of the vermis and the newly activated ipsilateral dentate nucleus were observed during performance of the serial reaction time task using the untrained right hand, accompanied by the cross-motor learning effect. However, no significant changes were observed in the control group. Our findings indicate that motor skills learned over the 2-week training using the trained limb were transferred to the opposi

关键词： neural regeneration neuroimaging cross-training effects motor skill learning cortical activation cerebellar activation serial reaction time task functional MRI response time response accuracy primary motor cortex dentate nucleus vermis grants-supported paper photographs-containingpaper neuroregeneration

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OWC air chamber performance prediction under impulse turbine damping effects

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Science China(Technological Sciences) 2016年第4期59卷 657-666页

作者： LIU Zhen hyun BeomSoo jiN ji Yuan HONG KeyYong LEE YoungYeon Shandong Provincial Key Laboratory of Ocean Engineering Ocean University of China Qingdao Municipal Key Laboratory of Ocean Renewable Energy Ocean University of China College of Ocean Science and Technology Korea Maritime and Ocean University Ocean Plant Research Division Korea Research Institute of Ships and Ocean Engineering

Oscillating water columns(OWCs)are most widely used in coastal wave energy *** air duct opens into the atmosphere through the air turbine,which is the power take-off device,and this results in a pressure drop across the air ***,because of the complex configure of the impulse turbine and its high rotation speed,it is difficult to install it in the experimental simulator and numerical ***,the turbine damping effects on the operation of the OWC air chamber are induced to predict its performance more *** plates are used as a substitute for the impulse turbine as it generates a similar pressure drop and power output;the experimental and numerical pressure drops and output powers are compared.A 3D numerical wave tank based on the two-phase VOF model is established using the commercial CFD code Fluent,which can predict air flow and pressure variations in the chamber and *** surface elevations,air flow velocity and pressure variation inside the chamber with the orifice plate are studied numerically,and validated by the corresponding experimental *** air chamber of the Yongsoo OWC pilot plant is used as the engineering project *** operating performance of the air chamber installed with a 0.428D orifice plate as the substitute for the designed impulse turbine is computed and *** is found that the turbine damping effects will cause around 30%reduction in the peak values of the pneumatic energy output of the OWC air chamber in the resonant wave domain.

关键词： oscillating water column air chamber turbine damping effects pressure drop orifice plate operating performance

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EXPERIMENTAL AND NUMERICAL STUDY FOR HYDRODYNAMIC CHARACTERISTICS OF AN OSCILLATING HYDROFOIL

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Journal of Hydrodynamics 2008年第3期20卷 280-287页

作者： LIU Zhen hyun Bcom-soo KIM Moo-rong jiN ji-yuan College of Engineering Ocean University of China Qingdao 266100 China College of Ocean Science and Technology Korea Maritime University Busan 606791 Korea Maritime and Ocean Engineering Research Institute Daejeon 305-343 Korea

The present article reports the experimental Particle Image Velocimetry （PIV） investigation and the corresponding numerical simulation results about the water flow over the oscillating hydrofoil and its unsteady dynamic characters. The experimental study focuses on the effect of mean angles of attack. The comparison between the PIV results and numerical prediction about the flow field using Fluent well demonstrates the capability of CFD on the simulation of the water flow around the pitching hydrofoil. The numerical results indicate that the forced oscillating frequencies have evident effects on the flow separation and vortex shedding. The simulations about the hydrodynamic drag and lift coefficients were also performed.

关键词： Particle Image Velocimetry (PIV) oscillating hydrofoil numerical simulation Fluent flow field force characteristics

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Influence of undissolved second-phase particles on dynamic recrystallization behavior of Mg–7Sn–1Al–1Zn alloy during low-and high-temperature extrusions

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Journal of Materials Science & Technology 2021年第12期71卷 87-97页

作者： hyun ji Kim Sang-Cheol jin Jae-Gil Jung Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu41566Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon51508Republic of Korea

This study investigates the effects of fine and coarse undissolved particles in a billet of the Mg–7 Sn–1 Al–1 Zn(TAZ711)alloy on the dynamic recrystallization(DRX)behavior during hot extrusion at low and high temperatures and the resultant microstructure and mechanical properties of the *** this end,partially homogenized(PH)and fully homogenized(FH)billets are extruded at temperatures of250 and 450°*** PH billet contains fine and coarse undissolved Mg_(2) Sn particles in the interdendritic region and along the grain boundaries,*** fine particles(<1μm in size)retard DRX during extrusion at 250°C via the Zener pinning effect,and this retardation causes a decrease in the area fraction of dynamically recrystallized(DRXed)grains of the extruded *** addition,the inhomogeneous distribution of fine particles in the PH billet leads to the formation of a bimodal DRXed grain structure with excessively grown grains in particle-scarce *** contrast,in the FH billet,numerous nanosized Mg_(2) Sn precipitates are formed throughout the material during extrusion at 250°C,which,in turn,leads to the formation of small,uniform DRXed grains by the grain-boundary pinning effect of the *** the PH billet is extruded at the high temperature of 450°C,the retardation effect of the fine particles on DRX is weakened by their dissolution in theα-Mg matrix and the increased extent of thermally activated grain-boundary *** contrast,the coarse Mg_(2) Sn particles in the billet promote DRX during extrusion through the particle-stimulated nucleation phenomenon,which results in an increase in the area fraction of DRXed *** both low and high extrusion temperatures,the extruded material fabricated using the PH billet,which contains both fine and coarse undissolved particles,has a lower tensile strength than that fabricated using the FH billet,which is virtually devoid of second-phase *** lower strength of the former is attributed mai

关键词： Mg–Sn alloy Second-phase particle Extrusion Homogenization Dynamic recrystallization

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Prediction models for recurrence in patients with small bowel bleeding

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World Journal of Clinical Cases 2023年第17期11卷 3949-3957页

作者： ji hyun Kim Seung-Joo Nam Division of Gastroenterology and Hepatology Department of Internal MedicineKangwon National University School of MedicineChuncheon 24341South Korea

Obscure gastrointestinal bleeding(OGIB)has traditionally been defined as gastrointestinal bleeding whose source remains unidentified after bidirectional *** can present as overt bleeding or occult bleeding,and small bowel lesions are the most common *** small bowel can be evaluated using capsule endoscopy,device-assisted enteroscopy,computed tomography enterography,or magnetic resonance *** the cause of smallbowel bleeding is identified and targeted therapeutic intervention is completed,the patient can be managed with routine ***,diagnostic tests may produce negative results,and some patients with small bowel bleeding,regardless of diagnostic findings,may experience *** those at risk of rebleeding can help clinicians form individualized surveillance *** studies have identified different factors associated with rebleeding,and a limited number of studies have attempted to create prediction models for *** article describes prediction models developed so far for identifying patients with OGIB who are at greater risk of *** models may aid clinicians in forming tailored patient management and surveillance.

关键词： Obscure gastrointestinal bleeding Prediction model Rebleeding Small bowel bleeding Video capsule endoscopy

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Continuity control method of cutter posture vector for efficient five-axis machining

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Journal of Central South University 2011年第6期18卷 1969-1975页

作者： hwang Jong-dae KIM Sang-myung JUNG hyun-chul JUNG Yoon-gyo School of Mechatronics Changwon National University

During five-axis machining of impeller, the excessive local interference avoidance leads to inconsistency of cutter posture, low quality of machined surface and increase of processing time. Therefore, in order to improve the efficiency of five-axis machining of impellers, it is necessary to minimize the cutter posture changes and create a continuous tool path while avoiding interference. By using an MC-space algorithm for interference avoidance, an MB-spline algorithm for continuous control was intended to create a five-axis machining tool path with excellent surface quality and economic feasibility. A five-axis cutting experiment was performed to verify the effectiveness of the continuity control. The result shows that the surface shape with continuous method is greatly improved, and the surface roughness is generally favorable. Consequently, the effectiveness of the suggested method is verified by identifying the improvement of efficiency of five-axis machining of an impeller in aspects of surface quality and machining time.

关键词： five-axis control machining configuration-space B-spline continuity control method impeller interference

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Ovalicin attenuates atopic dermatitis symptoms by inhibiting IL-31 signaling and intracellular calcium influx

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The Journal of Biomedical Research 2021年第6期35卷 448-458页

作者： Sung-hyun hwang Yeseul Yang Yeji Jeong Yongbaek Kim Laboratory of Clinical Pathology College of Veterinary MedicineSeoul National UniversitySeoul 08826Republic of Korea The Brain Korea 21 Future Veterinary Medicine Leading Education and Research Center College of Veterinary MedicineSeoul National UniversitySeoul 08826Republic of Korea Research Institute for Veterinary Science College of Veterinary MedicineSeoul National UniversitySeoul 08826Republic of Korea.

Atopic dermatitis(AD)is a common skin disorder difficult to be treated with *** study investigated the potential of ovalicin extracted from Cordyceps militaris for the treatment of AD using in vitro and in vivo *** found that,in canine macrophage cell line DH82,lipopolysaccharide(LPS)upregulated the expression of genes associated with inflammation and pruritic responses through activating calcium and interleukin-31(IL-31)signaling,and the upregulation could be suppressed by ovalicin,with an effect significantly stronger than *** also reduced the expression of IL-31 downstream genes,including JAK2(Janus kinase 2),TRPV1(transient receptor potential vanilloid receptor-1),and HRH2(histamine receptor H2).Ovalicin significantly alleviated the allergic symptoms in the AD mouse ***,the number of macrophages and mast cells infiltrated in the dermis was significantly reduced by ovalicin *** the skin tissue of AD mice,reduction of IL-31 receptor was observed in the ovalicin treated group compared to the group without ovalicin *** our knowledge,this is the first study to elucidate the anti-atopic mechanism of ovalicin,which could be an alternative to steroidal drugs commonly used for AD treatment.

关键词： ovalicin IL-31 pruritus inflammation calcium atopic dermatitis

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Effects of Initial and Boundary Conditions on Heavy Rainfall Simulation over the Yellow Sea and the Korean Peninsula:Comparison of ECMWF and NCEP Analysis Data Effects and Verification with Dropsonde Observation

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Advances in Atmospheric Sciences 2024年第9期41卷 1787-1803页

作者： jiwon hwang Dong-hyun CHA Donghyuck YOON Tae-Young GOO Sueng-Pil JUNG Department of Civil Urban Earth and Environmental Engineering Ulsan National Institute of Science and TechnologyUlsan 44919South Korea Program in Atmospheric and Oceanic Sciences Princeton UniversityPrincetonNew Jersey 08544USA National Institute of Meteorological Sciences NIMSJeju 63568South Korea

This study evaluated the simulation performance of mesoscale convective system(MCS)-induced precipitation,focusing on three selected cases that originated from the Yellow Sea and propagated toward the Korean *** evaluation was conducted for the European Centre for Medium-Range Weather Forecasts(ECMWF)and National Centers for Environmental Prediction(NCEP)analysis data,as well as the simulation result using them as initial and lateral boundary conditions for the Weather Research and Forecasting ***,temperature and humidity profiles from 3D dropsonde observations from the National Center for Meteorological Science of the Korea Meteorological Administration served as validation *** showed that the ECMWF analysis consistently had smaller errors compared to the NCEP analysis,which exhibited a cold and dry bias in the lower levels below 850 *** model,in terms of the precipitation simulations,particularly for high-intensity precipitation over the Yellow Sea,demonstrated higher accuracy when applying ECMWF analysis data as the initial *** advantage also positively influenced the simulation of rainfall events on the Korean Peninsula by reasonably inducing convective-favorable thermodynamic features(i.e.,warm and humid lower-level atmosphere)over the Yellow *** conclusion,this study provides specific information about two global analysis datasets and their impacts on MCS-induced heavy rainfall simulation by employing dropsonde observation ***,it suggests the need to enhance the initial field for MCS-induced heavy rainfall simulation and the applicability of assimilating dropsonde data for this purpose in the future.

关键词： initial conditions dropsonde heavy rainfall forecast global model analysis evaluation

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Anti-cancer effect of ethylacetate fraction from Orostachys japonicus on HT-29 human colon cancer cells by induction of apoptosis through caspase-dependent signaling pathway

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Asian Pacific Journal of Tropical Medicine 2018年第5期11卷 330-335页

作者： Deok-Seon Ryu hyun-ji Lee ji-Hye Kwon Dong-Seok Lee Department of Biomedical Laboratory Science Soonchunhyang University Department of Smart Foods and Drugs Graduate School of Inje University

Objective: To investigate the anti-colon cancer effects of ethylacetate fraction from Orostachys japonicus(0. japonicus) on HT-29 cancer cells. Methods: The viability of HT-29 cells was assayed by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium(MTS) method. Apoptosis induction and cell cycle inhibition were confirmed by fluorescein isothiocyanate and propidium iodide staining using flow *** changes in the nucleus were observed, using a fluorescence microscope with4',6-diamidino-2-phenylindole(DAPI) nuclear staining. The expression levels of the upstream and downstream proteins involved in the anti-cancer mechanism were confirmed by Western blotting. Results: After treating HT-29 cells with different concentrations of ethylacetate fraction from O. japonicus, the viability of cells decreased in a concentration-dependent manner,while apoptosis induction and apoptotic body formation increased. Cell cycle analysis showed that the arrest occurred at the sub-G_1 and S phase. Among the upstream and downstream proteins involved in anti-cancer activity, the level of B cell lymphoma-2 decreased, and the bcl-2-associated x protein increased. The level of pro-caspase-3, pro-caspase-8, and pro-caspase-9 decreased, while the level of cleaved-caspase-3, cleaved-caspase-8, and cleaved-caspase-9 increased. Moreover, the phosphorylation, that is, activation of extracellular signal regulated kinase 1/2, Jun-N-terminal kinase, and p38 increased. Conclusions: Combining the above results, it is thought that the survival of HT-29 cells is suppressed by ethylacetate fraction from0. japonicus through mitochondrial regulation-induced caspase cascade activation, induction of apoptosis and cell cycle arrest.

关键词： Orostachys japonicus HT-29 human colon cancer cells Anti-cancer activity Apoptosis Caspase cascade

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Rhamnus crenata leaf extracts exhibit anti-inflammatory activity via modulating the Nrf2/HO-1 and NF-κB/MAPK signaling pathways

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Asian Pacific Journal of Tropical Biomedicine 2022年第10期12卷 430-436页

作者： hyun ji Eo Da Som Kim Gwang Hun Park Special Forest Resources Division Department of Forest Bio-ResourcesNational Institute of Forest ScienceSuwon 16631Korea Forest Medicinal Resources Research Center National Institute of Forest ScienceYeongju 36040Korea

Objective:To elucidate the potential anti-inflammatory mechanisms of Rhamnus crenata leaf extracts using RAW264.7 ***:We used 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay to measure cell *** oxide(NO)production was measured using Griess *** blotting and RT-PCR assays were carried out for analyzing the protein and gene expressions of pro-inflammatory mediators,***,PD98059(ERK1/2 inhibitor),SB203580(p38 inhibitor),SP600125(JNK inhibitor),and BAY11-7082(NF-κB inhibitor)were used to evaluate the anti-inflammatory mechanism of Rhamnus crenata leaf ***:Rhamnus crenata leaf extracts significantly inhibited the production of the pro-inflammatory mediators such as NO,iNOS,COX-2,IL-1β,and TNF-αin lipopolysaccharide(LPS)-stimulated RAW264.7 *** crenata leaf extracts also suppressed LPS-induced degradation of IκB-αand nuclear accumulation of p65,which resulted in the inhibition of NF-κB activation in RAW264.7 ***,the extracts attenuated the phosphorylation of p38,ERK1/2,and JNK in LPS-stimulated RAW264.7 ***,HO-1 expression induced by Rhamnus crenata leaf extracts was significantly downregulated by SB230580,PD98059,SP600125 and ***:Rhamnus crenata leaf extract may upregulate HO-1 expression through inhibition of p38,ERK1/2,and NF-κB activation,which may contribute to the anti-inflammatory activity of the *** crenata leaf extracts may have great potential for the development of anti-inflammatory drugs to treat acute and chronic inflammatory diseases.

关键词： Anti-inflammatory activity Heme oxygenase-1 Nrf2 Mitogen-activated protein kinase Nuclear factor kappa B Rhamnus crenata

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