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Dual cycloid gear mechanism for automobile safety pretensioners

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Journal of Central South University 2012年第2期19卷 365-373页

作者： shin Joong-ho kIM Chang-hyun YUN Pyeong-hwa kWON Soon-man Department of Mechanical Design and Manufacturing Changwon National University

The most conventional vehicle pretensioner system consists of an internal gear pair with involute teeth. However, it has been well known that the corresponding gear pairs are relatively weak under the situation of impact loadings. To improve this phenomenon, a new pretensioning gear system with cycloid teeth rather than the involute ones was proposed, and dual cycloidal gear mechanisms were designed for satisfying geometric constraints and dynamic loading conditions. The simulations of the prototypes were conducted by LS-DYNA program and the experiments for a prototype were performed for a dynamic model with impact loading devices. The results show that the better operation and the smoother motion are confirmed in the proposed cycloidal gear system rather than the conventional one without interferences between gear teeth under the impact of a crash.

关键词： seat belt pretensioner internal gear pairs involute gear dual cycloid gear

Effects of electroacupuncture on the functionality of NG2-expressing cells in perilesional brain tissue of mice following ischemic stroke

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Neural Regeneration Research 2022年第7期17卷 1556-1565页

作者： Hong Ju Lee Da Hee Jung Nam kwen kim hwa.k.oung shin Byung Tae Choi Department of korean Medical Science School of Korean MedicinePusan National UniversityYangsanRepublic of Korea Graduate Training Program of korean Medicine for Healthy Aging Pusan National UniversityYangsanRepublic of Korea Department of korean Ophthalmology Otolaryngology and DermatologySchool of Korean MedicinePusan National UniversityYangsanRepublic of Korea

Neural/glial antigen 2(NG2)-expressing cells has multipotent stem cell activity under cerebral *** study examined the effects of electroacupuncture(EA)therapy(2 Hz,1 or 3 mA,20 minutes)at the Sishencong acupoint on motor function after ischemic insult in the brain by investigating the rehabilitative potential of NG2-derived cells in a mouse model of ischemic *** stimulation alleviated motor deficits caused by ischemic stroke,and 1 mA EA stimulation was more efficacious than 3 mA EA stimulation or positive control treatment with edaravone,a free radical *** properties of NG2-expressing cells were altered with 1 mA EA stimulation,enhancing their survival in perilesional brain tissue via reduction of tumor necrosis factor alpha *** stimulation robustly activated signaling pathways related to proliferation and survival of NG2-expressing cells and increased the expression of neurotrophic factors such as brain-derived neurotrophic factor,tumor growth factor beta,and neurotrophin *** the perilesional striatum,EA stimulation greatly increased the number of NG2-expressing cells double-positive for oligodendrocyte,endothelial cell,and microglia/macrophage markers(CC1,CD31,and CD68).EA therapy also greatly activated brain-derived neurotrophic factor/tropomyosin receptor kinase B and glycogen synthase kinase 3 beta *** results indicate that EA therapy may prevent functional loss at the perilesional site by enhancing survival and differentiation of NG2-expressing cells via the activation of brain-derived neurotrophic factor-induced signaling,subsequently ameliorating motor *** animal experiments were approved by the Animal Ethics Committee of Pusan National University(approval ***2019-2199 and PNU2019-2884)on April 8,2019 and June 19,2019.

关键词： brain-derived neurotrophic factor differentiation electroacupuncture motor function neural/glial antigen 2 perilesional striatum stroke survival

Dynamic Changes in Left and Right Cerebral Oxygen Saturation during Selective Cerebral Perfusion in Young Infants

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Congenital Heart Disease 2023年第6期18卷 639-647页

作者： hwa-Young Jang Sang-Jun Beon Sung-Hoon kim In-kyung Song Won-Jung shin Department of Anesthesiology and Pain Medicine Laboratory for Cardiovascular DynamicsAsan Medical CenterUniversity of Ulsan College of MedicineSeoul05505Korea Department of Physician Education and Training Asan Medical CenterSeoul05505Korea

Objectives:We investigated whether the selective cerebral perfusion(SCP)technique causes differences in changes in cerebral perfusion between both hemispheres in young infants,using cerebral oxygen saturation(ScO2)as an ***,we determined the association between the discrepancy in ScO2 and cerebral perfu-sion pressure during ***:The difference in ScO2 between the left and right cerebral hemispheres(ΔScO2 Rt-Lt)was calculated during clamping of the innominate artery(IA)and during ***:In 25 infants(aged 2 to 78 days),the left and right ScO2 were well maintained(median 63.2%and 60.9%during IA clamping,respectively;64.0%and 65.6%during SCP,respectively).During IA clamping,right and left ScO2 decreased(med-ian-1.4%and-1.0%,respectively).During SCP,rightΔScO2 was higher compared to leftΔScO2(median 1.5%vs.0.6%;poung infants;this may depend on the perfusion pressure.

关键词： Cerebral circulation congenital heart defects monitoring near-infrared spectroscopy

Subacute electroacupuncture at Baihui (GV 20) and Dazhui (GV 14) promotes post-stroke functional recovery via neurogenesis and astrogliosis in a photothrombotic stroke mouse model

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Journal of Traditional Chinese Medicine 2019年第6期39卷 833-841页

作者： Young-Wook Park Gi Yoon Heo Min Jae kim Seo-Yeon Lee Byung Tae Choi hwa.k.oung shin Division of Meridian and Structural Medicine School of Korean MedicinePusan National UniversityYangsanGyeongnam 50612Republic of Korea Department of korean Medical Science School of Korean MedicinePusan National UniversityYangsanGyeongnam 50612Republic of Korea Graduate Training Program of korean Medicine for Healthy-Aging Pusan National UniversityYangsanGyeongnam 50612Republic of Korea korean Medical Science Research Center for Healthy-Aging Pusan National UniversityYangsanGyeongnam 50612Republic of Korea

OBJECTIVE:To investigate the optimal timing and underlying mechanism of electroacupuncture(EA)at Baihui(GV 20)and Dazhui(GV 14)for improved long-term functional recovery after focal cerebral ischemia in a photothrombotic stroke mouse ***:Totally 50 adult male C57 BL/6 J mice were assigned into 5 groups:(a)the control group,sham-operated mice(n=10);(b)the vehicle group,focal cerebral ischemia induction without EA(n=10);(c)the acute EA group,mice received EA immediately post-ischemia,followed by once-daily treatments for 7 consecutive days(n=10);(d)the subacute EA group,mice received EA 4 days post-ischemia,followed by once-daily treatments for 7 consecutive days(n=10);(e)the delayed EA *** stimulation(2 Hz,2 V for 20 min)was applied to acupuncture points(acupoints),Baihui(GV 20)and Dazhui(GV 14),once a day for 7 consecutive days beginning immediately(acute treatment),4 d(subacute treatment)and 10 d(delayed treatment)after focal cerebral ischemia in C57 BL/6 J *** assessments were conducted 21 and 28 d post-ischemia and histopathological analyses were performed 28 days ***:The subacute EA treatment at Baihui(GV20)and Dazhui(GV 14)significantly improved functional recovery compared to the vehicle group 28 d after ischemic brain injury,although brain atrophy was not *** number of Neu N+and Neu N+/Brd U+cells as well as GFAP intensity in the ipsilateral cortex were significantly increased in the subacute group compared to the vehicle group 28 d *** concluded that EA stimulation 4 d post-ischemia(subacute treatment)enhanced neurogenesis and astrogliosis,likely contributing to long-term functional recovery following focal cerebral ***:Our findings suggest that the timing of the EA therapy at Baihui(GV 20)and Dazhui(GV 14)determines the therapeutic effects in mice with focal cerebral ischemia induced by photothrombotic occlusion.

关键词： Electroacupuncture Stroke Astrocytes Neurogenesis Post-stroke remodeling

Effects of Cordyceps militaris extract on angiogenesis and tumor growth

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Acta Pharmacologica Sinica 2004年第5期25卷 115-123页

作者： hwa-seung YOO,Jang-woo shin,Jung-hyo CHO,Chang-gue SON,Yeon-weol LEE,Sang-yong PARk,Chong-kwan CHO Daejeon University Daejeon 301-724 Department of East-West Cancer Center College of Oriental Medicine Daejeon University Daejeon 301-724 Department of East-West Cancer Center College of Oriental Medicine Daejeon University Daejeon 301-724 Department of East-West Cancer Center R&D Lab of Bulrolife Co Ltd Daejeon korea College of Oriental Medicine Daejeon University Daejeon 301-724 Institute ofTraditional Medicine and Bioscience Daejeon University Daejeon 301-724 Department of East-West Cancer Center College of Oriental Medicine

AIM: To evaluate the effects of Cordyceps militaris extract (CME) on angiogenesis and tumor growth. METHODS:Human umbilical vein endothelial cells (HUVEC), HT1080, and B16-F10 cells were used. DNA fragment, angio-genic related gene expressions (MMPs, bFGF, VEGF, etc), capillary tube formation, wound healing in vitro, tumorgrowth in vivo were measured. RESULTS: CME inhibited growth of HUVECs and HT1080 (P<0.01). CME 100and 200 mg/L reduced MMP-2 gene expression in HT1080 cells by 6.0 % and 22.9 % after 3-h and 14.9 % and32.8 % after 6-h treatment. CME did not affect MMP-9 gene expression in B16-F10 melanoma cells. CME 100 and200 mg/L also reduced bFGF gene expression in HUVECs by 22.2 % and 41.3 %. CME inhibited tube formation ofendothelial cells in vitro and in vivo. CME repressed the growth of B16-F10 melanoma cells in mice compared withcontrol group (P<0.05). CONCLUSION: CME has antiangiogenetic properties.

关键词： Cordyceps militaris angiogenesis human umbilical vein endothelial cells HT1080 cells B16-F10cells matrix metalloproteinases basic fibroblast growth factor

A novel chitosan nanocapsule for enhanced skin penetration of cyclosporin A and effective hair growth in vivo

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Nano Research 2019年第12期12卷 3024-3030页

作者： Jin Sil Lee Youngmin hwang Hyeryeon Oh Sunghyun kim Jin-hwa kim Jeung-Hoon Lee Yong Chui shin Giyoong Tae Won II Choi Center for Convergence Bioceramic Materials Convergence R&D DivisionKorea Institute of Ceramic Engineering and Technology202Osongsaengmyeong l-rof Osong-eupHeungdeok-guCheongjuChungbuk 28160Republic of Korea School of Materials Science and Engineering Gwangju Institute of Science and Technology123 Cheomdan-gwagiroBuk-guGwangju 61005Republic of Korea SkINMED Co. Ltd.Daejeon 34028Republic of Korea Amicogen Inc.64 Dongburo 1259JinsungJinju 52621Republic of Korea

Hair loss due to medical conditions,such as alopecia,male pattern baldness,and cancer chemotherapy treatment,has been a comm onproblem for many in *** n A(CsA),a fungal metabolite,has been reported to be a hair growth modulatory agent and is apotential drug for hair ***,the effect of topical application of CsA is limited by its poor water *** deliverysystems developed to enhance its solubility still showed poor skin *** overcome these limitations,in this study,we have developed a novel chitosan nanocapsule platform using Pluro nic F127 and chitosan without any chemical crosslinking or complicated preparati on steps for the enhanced water solubility and high tran sdermal penetration of *** chitosan nanocapsules(ChiNCs)optimized in terms of structural stability by using chitosan with various molecular weights ranging from 3 to 100 kDa enhanced the skin permeation of CsA through humancadaver skin in *** administration of the CsA loaded ChiNCs in creased the hair follicles by c.a.7 times higher than that of thecontrol group,and effectively induced hair growth in C57BL/6 mice in *** results suggest that ChiNCs could be used as a platform foreffective transdermal delivery of various hydrophobic drugs.

关键词： chitosan nanocapsule cyclosporin A transdermal delivery hair growth

Low cycle fatigue properties and cyclic deformation behavior of as-extruded AZ31 magnesium alloy

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Transactions of Nonferrous Metals Society of China 2010年第B7期20卷 533-539页

作者： S.kWON k.SONG k.S.shin S.I.kWUN Department of Materials Science and Engineering Korea University School of Materials Science and Engineering Seoul National University

The low cycle fatigue(LCF)properties of as-extruded AZ31 Mg alloy were investigated under total strain amplitudes in the range of 0.4%-1.2%with strain rate of 1×10- 2s -*** to the twinning effect in compression during loading and the detwinning effect during unloading,the alloy showed an asymmetric hysteresis *** cyclic stress response exhibited cyclic hardening at high total strain *** cyclic deformation behaviors were discussed using the Coffin-Manson plot,which divided the plastic strain amplitudes into the tension side and the compression *** the LCF tests that were started from either tension or compression under a total strain amplitude of 1.0%,the interaction between the twinning effect and dislocation was *** twinning effect during the LCF test and the variation of the dislocation density were investigated using optical microscopy and transmission electron microscopy,respectively.

关键词： AZ31 magnesium alloy low cycle fatigue twinning dislocation

Clawed Miniature Inchworm Robot Driven by Electromagnetic Oscillatory Actuator

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Journal of Bionic Engineering 2015年第4期12卷 519-526页

作者： kyung-min Lee Youngshik kim Jamie k. Paik Buhyun shin korean Intellectual Property Office Gov. Complex-Daejeon Bldg. 4 189 Cheongsa-ro Se-gu Daejeon 302-701 Korea Department of Mechanical Engineering Hanbat National University 125 Dongseodaero Yuseong-gu Daejeon 305-719 Korea The Institute of Mechanical Engineering EPFL STIlGM UPPAIK BM 4118 (B~timent BM) Station 17 Switzerland

In this research we propose a novel inchworm robot, which is composed of an Electromagnetic Oscillatory Actuator （EOA） and claws. The EOA consists of a yoke, a magnet, and a coil. The overall robot size is 12.2 mm x 11 mm x 9 mm （length x height ~ width）. The locomotion of the robot is achieved by different amounts of slips when the robot stretches and contracts its front leg. To realize locomotion, the working conditions were calculated theoretically and the calculated input signal was applied to the robot. The performance of the inchworm robot was evaluated experimentally with varying input voltages and frequencies. A simple op-amps based driving circuit was used to provide a square-wave input. Travel speed, average distance per step of the robot, and moving distance of the leg and body at each step were measured. The maximum travel speed was 36 mm-s-1 at 30 Hz, which validates our simple locomotion strategy experimentally.

关键词： electromagnetic actuator micro mobile robot inchworm crawler locomotion

Effect of texture and twinning on mechanical properties and corrosion behavior of an extruded biodegradable Mg-4Zn alloy

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Journal of Magnesium and Alloys 2019年第4期7卷 707-716页

作者： M.Sabbaghian R.Mahmudi k.S.shin School of Metallurgical and Materials Engineering College of EngineeringUniversity of TehranTehran 14395-515Iran Magnesium Technology Innovation Center School of Materials Science and EngineeringSeoul National University1 Gwanak-roGwanak-guSeoul 08826Republic of Kore

Microstructure,texture,mechanical properties and corrosion behavior of the extruded Mg-4Zn alloy,as a biodegradable material,were investigated.A refined microstructure caused by dynamic recrystallization(DRX),and a general fiber texture were achieved after *** properties along different directions of the extruded samples were investigated using shear punch test(SPT).The shear yield stress(SYS)of 113.8 MPa obtained in the transverse direction(TD)was higher than the 106 MPa achieved for the extruded direction(ED)and 45˚*** was attributed to the higher amounts of twins and also lower Schmid factor(SF)in the *** the other hand,encouraged activation of the basal slip system in the 45˚samples resulted in improved room temperature formability,as indicated by the normalized displacement in the SPT *** back scattered diffraction(EBSD)analysis of the surfaces corroded in the phosphate buffered saline(PBS)solution,showed that despite having similar grain sizes and second phase particles shape and volume fractions,surfaces containing grains near(0001)orientations and extension twins(TD and 45˚samples)have lower corrosion rates,as compared to the ED specimens.

关键词： Mg-Zn alloy Corrosion rate Dynamic recrystallization Texture Twinning