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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

Nanomolar concentration of alpha-synuclein enhances dopaminergic neuronal survival via Akt pathway

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Neural Regeneration Research 2013年第35期8卷 3269-3274页

作者： ji-Young Kim Beom Seok Jeon Han-Joon Kim tae-Beom Ahn Department of Neurology Inje University Seoul Paik Hospital Department of Neurology College of Medicine Seoul National University Hospital Department of Neurology Kyung Hee University Medical Center

Although alpha-synuclein is generally thought to have a pathological role in parkinson＇s disease, accumulative evidence exists that alpha-synuclein has a neuroprotective effect. The aim of this study was to evaluate the effect of extracellular alpha-synuclein on dopaminergic cell survival. We assessed cell viability using the 3-（4,5-dimethyt-thiazol-2-yt）-2,5-diphenyltertazolium bromide （MTT） assay both in undifferentiated SH-SY5Y （SHSY） cells and neuronally-differentiated SH-SY5Y （ndSHSY） cells after 24 hour treatment with monomeric alpha-synuclein at various concentrations （0 [control], 50, 100 nmol/L, 1 IJmol/L）. To determine whether cell viability assessed by MTT assay was affected by cell proliferation, 5-bromo-2＇-deoxyuridine （BrdU） incorporation assay was per- formed. Level of both Akt and phosphorylated Akt was measured using western blot method in ndSHSY cells with or without 24 hour alpha-synuclein treatment. Cell viability was increased in ndSHSY cells at the nanomolar concentration of alpha-synuclein, but not in SHSY cells. Proportion of BrdU-positive ndSHSY cells was decreased in alpha-synuclein-treated group compared with control group. Level of phosphorylated Akt in alpha-synuclein-treated group was higher compared with the control group. Our study shows that extracellular alpha-synuclein at nanomolar concentra- tion benefits dopaminergic cell survival via Akt pathway.

关键词： neural regeneration alpha-synuclein neuronal survival nanomolar extracellular phosphorylatedAkt SH-SY5Y cell neuronal differentiation proliferation dopaminergic 5-bromo-2'-deoxyuridine grants-supported paper neuroregeneration

Effect of pre-deformation on precipitation behavior of AZ80 alloy:Comparison of slip-and twinning-dominant deformation

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Journal of Magnesium and Alloys 2024年第9期12卷 3616-3630页

作者： Hyun ji Kim Sang Cheol jin Sumi Jo Sung Hyuk park Department of Materials Science and Metallurgical Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Graduate School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea

This study investigates the effect of the deformation mode on the precipitation behavior of an extruded Mg-8.0Al-0.5Zn-0.2Mn(AZ80)*** alloy samples are compared after the application of 3.5%tension and 3.5%compression along the extrusion direction to induce slip-dominant and twinning-dominant deformation modes,*** pre-compressed(PC)sample,which contained numerous{10-12}tension twins,has a reduced grain size and a higher internal strain than the pre-tensioned(PT)sample,which is attributed to the inherent internal strain that occurs during the formation and growth of the *** a result,the precipitation behavior of the PC sample is accelerated,leading to its short peak aging time of 32 h,which is lower than those of the PT and as-extruded samples(48 and 100 h,respectively).Furthermore,fine continuous precipitates(CPs)rapidly form within the{10-12}twins,contributing to the enhanced *** precipitates(DPs),which have a hardness comparable to the CP-containing twinned regions,in the PC sample experience less coarsening during aging than those in the PT sample due to growth inhibition by the{10-12}***,the{10-12}twins generated under the twinning-dominant deformation condition lead to enhanced precipitation behaviors,including the preferential formation and refinement of CPs and the suppressed coarsening of ***,pre-deformation that occurs{10-12}twinning exhibits more pronounced effects on precipitation acceleration and microstructural modification than slip-inducing pre-deformation.

关键词： AZ80 alloy Slip Twinning Precipitation Hardness

Driving characteristics of octagon-type ultrasonic motor

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Journal of Central South University 2013年第1期20卷 71-75页

作者： KIM Jong-Wook park Choong-Hyo LIM Jung-Hoon JEONG Seong-Su park Jong-Kyu park tae-Gone Changwon National University Sarim-dongChangwon-siGyeongsangnam-do641-773Korea

Structure of the octagon-type ultrasonic motor was proposed and designed so as to allow the motor to drive small actuator. The stator of the motor consisted of the octagon shape elastic body and four rectangular plate ceramics. The four ceramics were attached to outer surfaces of the octagon elastic body. The same phase voltages were applied to the ceramics on horizontal surfaces, and 90° phase difference voltages were applied to the ceramics on vertical surfaces. When the AC voltage with 90° phase difference was applied in ceramics, the elliptical displacement of unimorph bars was generated by generating bending vibration. To find the maximum displacement model that generates elliptical displacement at the centers of the inner surfaces, the finite element analysis program ATILA was used. The analyzed results were compared to the experimental results. As a result, the speed and torque are increased linearly by increasing the input voltage and the speed of motors can be controlled by changing the applied voltages.

关键词： octagon-type 90° phase difference ultrasonic motor ATILA

Acetylsalicylic acid for metal stent in malignant distal common bile duct obstruction:A randomized controlled trial

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Hepatobiliary & Pancreatic Diseases International 2022年第5期21卷 493-499页

作者： jin Ho Choi Kyong Joo Lee Woo Hyun Paik Namyoung park Jung Won Chun Sang Hyub Lee ji Kon Ryu Yong-tae Kim Department of Internal Medicine Liver Research InstituteSeoul National University College of MedicineSeoulKorea Department of Internal Medicine Yonsei University Wonju College of MedicineWonjuKorea

Background:Endoscopic biliary drainage is the treatment of choice for patients with malignant distal common bile duct ***-expandable metal stents have clinical advantages including an increased duration of patency that may be prolonged by acetylsalicylic acid(ASA)*** aim of this study was to investigate whether ASA had a positive effect on the patency of self-expandable metal stents compared with ***:This prospective,multicenter,double-blinded,and randomized placebo-controlled trial was conducted from October 2017 to May 2020 in *** who underwent palliative endoscopic biliary drainage with self-expandable metal stents for malignant distal bile duct obstruction were enrolled,and allocated to ASA treatment or *** study outcomes were the rate of stent dysfunction at 6 months,duration of stent patency,risk factors for stent dysfunction,and any adverse ***:Interim analysis included 24 and 28 patients in the ASA and placebo groups,*** was no significant difference between the ASA and placebo groups in stent dysfunction(25.0%vs.20.7%,P=0.761)or the duration of stent patency(150.97±10.55 vs.158.07±8.70 days,P=0.497).Six patients experienced suspected ASA-related adverse events,and there was one lethal ***:ASA did not prolong stent *** study was terminated early because of the possibility of serious adverse events related to ASA treatment of these patients receiving palliative care.

关键词： Endoscopic retrograde cholangiopancreatography Self expandable metallic stents Randomized controlled trial Acetylsalicylic acid

Enhanced thermoelectric composite performance from mesoporous carbon additives in a commercial Bi_(0.5)Sb_(1.5)Te_(3) matrix

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Journal of Materials Science & Technology 2021年第35期94卷 175-182页

作者： Seong-tae Kim Jong Min park Kwi-Il park Sang-Eun Chun Ho Seong Lee Pyuck-Pa Choi Seonghoon Yi School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak-roYuseong-guDaejeon 34141Republic of Korea

Composites were prepared,through hot pressing,using carbon materials with different pore size distributions as additives for commercial Bi_(0.5)Sb_(1.5)Te_(3) thermoelectric material(BST,p-type).Thermoelectric properties of the composites were measured in a temperature range of 298-473 *** conductivity of the composites,especially lattice thermal conductivity,was effectively decreased due to the mesoporous properties of the incorporated carbon *** electrical conductivity of the composites slightly decreased due to the electron scattering at the interface between the carbon material and the commercial BST *** composite with 0.2 vol.%mesoporous carbon powder(36%mesoporosity)exhibited a figure of merit value approximately 10.7%higher than that of commercial BST without *** behavior resulted in 116%improved output power in the composite block-based single element compared with a bare BST thermoelectric *** enhanced figure of merit was attributed to the effective reduction of lattice thermal conductivity by acoustic phonons scattering at the interface between the BST matrix and the mesoporous carbon as well as at the pore surfaces within the mesoporous *** utilizing mesoporous carbon materials used in this study,the shortcomings and economic difficulties of the composite process with low dimensional carbon additives(carbon nanotubes,graphene,and nanodiamond)can be overcome for extensive practical *** carbon powder with a tailored porosity distribution revealed the validity of bulk-type carbon additives to enhance the figure of merit of commercial thermoelectric materials.

关键词： Thermoelectric material Bi_(0.5)Sb_(1.5)Te_(3) Mesoporous carbon Lattice thermal conductivity Figure of merit

Duodenal obstruction following acute pancreatitis caused by a large duodenal diverticular bezoar

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World Journal of Gastroenterology 2012年第38期18卷 5485-5488页

作者： ji Hun Kim Jae Hyuck Chang Sung Min Nam Mi Jeong Lee Il Ho Maeng jin Young park Yun Sun Im tae Ho Kim Il Young park Sok Won Han Department of Internal Medicine College of Medicine The Catholic University of Korea Seoul 137-701 South Korea Department of Surgery College of Medicine The Catholic University of Korea Seoul 137-701 South Korea

Bezoars are concretions of indigestible materials in the gastrointestinal tract. It generally develops in patients with previous gastric surgery or patients with delayed gastric emptying. Cases of periampullary duodenal divericular bezoar are rare. Clinical manifestations by a bezoar vary from no symptom to acute abdominal syndrome depending on the location of the bezoar. Biliary obstruction or acute pancreatitis caused by a bezoar has been rarely reported. Small bowel obstruction by a bezoar is also rare, but it is a complication that requires surgery. This is a case of acute pancreatitis and subsequent duodenal obstruction caused by a large duodenal bezoar migrating from a periampullary diverticulum to the duodenal lumen, which mimicked pancreatic abscess or microperforation on abdominal computerized tomography. The patient underwent surgical removal of the bezoar and recovered completely.

关键词： Bezoar Diverticulum Pancreatitis Duodenal obstruction

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

Removal of press-through-packs impacted in the upper esophagus using an overtube

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World Journal of Gastroenterology 2006年第36期12卷 5909-5912页

作者： Yeon Seok Seo Jong-Jae park ji Hoon Kim jin Yong Kim Jong Eun Yeon Jae Seon Kim Kwan Soo Byun Young-tae Bak Department of Internal Medicine Korea University Medical Center Guro Hospital Seoul Korea Department of Internal Medicine Sungkyunkwan University School of Medicine Seoul Korea

Foreign bodies in the upper esophagus should be re-moved as soon as possible to avoid serious complica-tions. However, removals of foreign bodies in the upper esophagus are very difficult, especially if they have sharp edges, such as press-through-packs (PTPs). We expe-rienced four cases of the impacted PTPs in the upper esophagus which was successfully extracted endoscopi-cally with the overtube. Because two edges of PTPs were so firmly impacted in the esophageal wall in all cases, the PTPs were not movable in the upper esophagus. However, after insertion of the overtube, PTPs became movable and were successfully extracted and no serious complications occurred after extraction of PTPs. In one case, insertion of the overtube rapidly expanded the up-per esophagus and PTP progressed to the gastric cavity and it could be extracted with the endoscopic protector hood. The endoscopic removal with the overtube was a simple, safe and effective technique for the removal of the impacted PTPs in upper esophagus.

关键词： Esophagus Foreign body Endoscopy