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Understanding pediatric surgical needs in North Korea: a modeling analysis

World journal of Pediatric Surgery 2024年第1期7卷 47-53页

作者： Phillip j Hsu Sangchul Yoon Kee B park University of Michigan Ann ArborMichiganUSA Department of Global Health and Social Medicine Harvard Medical SchoolBostonMassachusettsUSA Department of Medical Humanitiesand Social Sciences Yonsei University SeoulSouth Korea

Background Sixty-five percent of children worldwide lack access to surgical care,the majority of whom live in low-income and middle-income countries(LMics).Developing surgical infrastructure requires information on surgical need;however,this information is often limited in *** Korea(Democratic People's Republic of Korea,DPRK)has a low amount of publicly available ***,we analyzed available modeled data to understand the causes of pediatric deaths due to conditions treatable with surgery in *** We used World Bank data and models from the Institute for Health Metrics and Evaluation to identify causes of pediatric deaths affecting pediatric patients(agecompared mortality of disease between DPRK and countries with similar economic *** Between 1990 and 2019,the number of overall pediatric deaths has *** 2019,32.2%of allpediatric deaths in DPRK were caused by surgical *** leading categories of surgical conditions were injuries(53.9%),congenital conditions(34.2%),tumors(8.8%),and abdominal conditions(3.2%).DPRK has a lower relative rate of pediatric deaths compared with other LMIcs with similar gross domestic product per ***,it has a higher relative rate of pediatric deaths due to conditions requiring treatment with *** injuries contribute significantly to the high rate of pediatric deaths in *** Although DPRK may be allocating overall resources toward pediatric healthcare more efficiently than economic peers,DPRK may benefit from improvement in pediatric surgical *** availability of data and close international collaboration could be potential solutions to bridge this gap.

关键词： pediatric surgical injuries

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Effects of serum containing natural cerebrolysin on glucose-regulated protein 78 and ccAAT enhancer-binding protein homologous protein expression in neuronal Pc12 cells following tunicamycin-induced endoplasmic reticulum stress

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Neural Regeneration Research 2009年第2期4卷 92-97页

作者： Zhengzhi Wu Ming Li Andrew c.j. Huang O Xiuqing jia Yinghong Li Manyin chen Shenzhen Hospital Southern Medical University Shenzhen 518033 Guangdong Province China Larry Hiflblom Islet Research center David Geffen School of Medicine UCLA Los Angeles CA 90024 USA

BAcKGROUND： Glucose-regulated protein 78 （GRP78）, a marker of endoplasmic reticulum stress, can prolong cell survival. Alternatively, ccAAT enhancer-binding protein homologous protein （cHOP）, a transcription factor specific for endoplasmic reticulum stress, can cause cell cycle arrest and cell apoptosis. OBjEcTIVE： To study the protective effects of serum containing natural cerebrolysin on endoplasmic reticulum stress in tunicamycin-induced neuronal Pc12 cells, and analyze the influence on GRP78 and cHOP expressions. DESIGN, TIME AND SETTING： A parallel controlled study was performed at the Institute of Integrated Western and Traditional chinese Medicine, Shenzhen Hospital, Southern Medical University, between March 2006 and August 2008. MATERIALS： Adult Sprague-Dawley rats were perfused with natural cerebrolysin aqueous extract （0.185 g/kg/d） to produce serum containing natural cerebrolysin. Physiological saline was used to produce blank serum. Pc12 cell line was provided by Shanghai Institute of cell Biology, chinese Academy of Science. Tunicamycin was provided by Sigma （St. Louis, USA）, and natural cerebrolysin, containing ginseng, rhizoma gastrodiae, and gingko leaf （1：2：2）, by Shengzhen Institute of Integrated Western and Traditional chinese Medicine. METHODS： Pc12 cells were treated with DMEM culture media containing 10% blank serum （normal control group）, tunicamycin （1 μg/mL; model group）, and 5%, 10%, and 15% serum containing natural cerebrolysin and tunicamycin （1 μ g/mL; low-, moderate-, and high-dose serum containing natural cerebrotysin groups）, for 2 hours. MAIN OUTcOME MEASURES： Pc12 cells were treated with tunicamycin for 48 hours after which apoptosis was measured using the TUNEL method to calculate apoptotic index. GRP78 expression was detected using immunocytochemistry. After 24 hours of treatment with tunicamycin, GRP78 and cHOP mRNA expressions were measured using RT-PcR. RESULTS： The apoptotic index and cHOP mRNA expression were in th

关键词： natural cerebrolysin Pc12 cell strain endoplasmic reticulum stress tunicamycin glucose regulated protein 78 ccAAT/enhancer-binding protein homologous protein

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Vibration control of fluid-conveying pipes: a state-of-the-art review

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Applied Mathematics and Mechanics(English Edition) 2023年第9期44卷 1423-1456页

作者： Hu DING j.c.j. Shanghai Key Laboratory of Mechanics in Energy Engineering School of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China Shaoxing Institute of Technology Shanghai UniversityShaoxing 312074Zhejiang ProvinceChina Shanghai Institute of Aircraft Mechanics and control Shanghai 200092China School of Mechanical and Mechatronic Engineering University of Technology SydneyNew South Wales 2007Australia

Fluid-conveying pipes are widely used to transfer bulk fluids from one point to another in many engineering *** are subject to various excitations from the conveying fluids,the supporting structures,and the working environment,and thus are prone to vibrations such as flow-induced vibrations and acoustic-induced *** can generate variable dynamic stress and large deformation on fluid-conveying pipes,leading to vibration-induced fatigue and damage on the pipes,or even leading to failure of the entire piping system and catastrophic ***,the vibration control of fluid-conveying pipes is essential to ensure the integrity and safety of pipeline systems,and has attracted considerable attention from both researchers and *** present paper aims to provide an extensive review of the state-of-the-art research on the vibration control of fluid-conveying *** vibration analysis of fluid-conveying pipes is briefly discussed to show some key issues involved in the vibration ***,the research progress on the vibration control of fluid-conveying pipes is reviewed from four aspects in terms of passive control,active vibration control,semi-active vibration control,and structural optimization design for vibration ***,the main results of existing research on the vibration control of fluid-conveying pipes are summarized,and future promising research directions are recommended to address the current research *** paper contributes to the understanding of vibration control of fluid-conveying pipes,and will help the research work on the vibration control of fluidconveying pipes attract more attention.

关键词： fuid-conveying pipe vibration passive control nonlinear energy sink(NES) active control semi-active control

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Aerodynamic force generation of an insect-inspired flapper actuated by a compressed unimorph actuator

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chinese Science Bulletin 2009年第16期54卷 2871-2879页

作者： NGUYEN Quoc-Viet park Hoon c GOO Nam S BYUN Doyoung Department of Advanced Technology Fusion Konkuk University National Research Laboratory for Biomimetics and Intelligent Microsystems Konkuk University Department of Aerospace Engineering Konkuk University

We examined experimentally the flapping performance in terms of aerodynamic force generation of an insect-inspired flapper actuated by both of original LIPcA and compressed LIPcA. Flapping tests for two artificial wing shapes of horse botfly and hawk moth were conducted at the wing rotation angle of 60° and a flapping frequency range from 6 Hz to 12 Hz to find the optimum flapping frequency and to investigate the effect of compressed LIPcA and wing shape on the force generation. Flapping tests in the vacuum were also undertaken to measure the induced inertia force. The aerodynamic force was calculated by subtracting the inertia force from the total force measured in the air. It was found that the average inertia force was relatively small when compared with the average total force. The use of the compressed LIPcA could significantly improve the flapping angle of the flapper from 110° to 130° (18.2% increase) resulting in 24.5% increase in the average aerodynamic force. It was also found that flapper with hawk moth wings could produce larger force than the flapper with horse botfly wings.

关键词：空气动力驱动器插板压缩部队昆虫压电片单层

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Influence of the electrolyte conductivity on the critical current density and the breakdown voltage

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chinese journal of chemical Engineering 2023年第7期59卷 169-175页

作者： Hae-Kyun park Dong-Hyuk park Bum-jin chung Department of Nuclear Engineering Kyung Hee University 1732 Deogyeong-daeroGiheung-guYongin-siGyeonggi-do 17104Korea

The work investigates influence of the electrolyte conductivity on the onset of partial contact glow discharge electrolysis(cGDE)in a water *** current density(ccD)and breakdown voltage were measured together with in situ observation of hydrogen bubble behavior,whose influence has not been focused *** a fixed current during normal electrolysis,hydrogen coalescence adjacent to cathode surface was invigorated at a lower *** analyses elucidated the hydrogen coalescence characteristics by quantifying size and population of detached hydrogen *** ccD increased about 104% within given range of conductivity(11.50-127.48 mS·cm^(-1))due to impaired bubble coalescence,which delays hydrogen film formation on the ***,decreasing trend of breakdown voltage was measured with increased conductivity showing maximum drop of 74%.It is concluded that onset of partial cGDE is directly affected by hydrodynamic bubble behaviors,whereas the electrolyte conductivity affects the bubble formation characteristics adjacent to cathode electrode.

关键词： Water electrolysis critical current density Breakdown voltage Electrolyte conductivity Hydrogen bubble behavior

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Effect of Sb Addition on Microstructure and Mechanical Properties of Al-18B-4O-33/AS-52 Magnesium Matrix composites

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journal of Materials Science & Technology 2008年第1期24卷 99-101页

作者： Wookjin Lee Ikmin park x Yongho park School of Materials Science and Engineering Pusan National University San 30 Jangjeon-dong Geumjeong-gu Busan 609-735 Korea

The effect of antimony addition on the microstructure of Mg-Al-Si magnesium matrix composite was investi- *** addition of Sb can modify the morphology of Mg-2Si particles which have chinese script shape to fine polygonal *** matrix composite with Alborex whisker was successfully fabricated by using a squeeze infiltration *** strength and elongation were increased in the Sb modified alloy and the composite at both room and high temperatures.

关键词： Magnesium Metal matrix composites (MMc) composite

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Dynamic Mechanical Relaxation in Bulk Metallic Glasses:A Review

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journal of Materials Science & Technology 2014年第6期30卷 523-545页

作者： j.c.Qiao j.M.Pelletier Université de Lyon CNRS France INSA-Lyon MATEIS UMR5510 F-69621 Villeurbanne France

Metallic glasses have aroused considerable interest in the past decades because they exhibit fascinating properties. First, this article briefly outlines the mechanical, thermal properties and application of the metallic glasses. In addition, we focus on the dynamic mechanical relaxation behaviors, i.e. main （α） and secondary （β） relaxations, in metallic glasses. The mechanical relaxation behaviors are connected to the mechanical properties and physical properties in glassy materials. The main relaxation in glassy materials is related to the glass transition phenomenon and viscous flow. On the other hand, the β relaxation is linked to many fundamental issues in metallic glasses. In these materials relaxation processes are directly related to the plastic deformation mechanism. The mechanical relaxations, particularly, the β relaxation provides an excellent opportunity to design metallic glasses with desired physical and mechanical properties. We demonstrate the universal characteristics of main relaxation in metallic glasses. The phenomenological models and the physical theories are introduced to describe the main relaxation in metallic glasses. In parallel, we show the dependence of the α. and β relaxations on the thermal treatments in metallic glasses. Finally, we analyze the correlation between the atomic mobility and the thermo-mechanical treatments in metallic glasses. On the one hand, the atomic mobility in metallic glasses is reduced by physical aging or crystallization. On the other hand, the atomic mobility in metallic glass is enhanced by deformation （i.e. compression and cold rolling）. Importantly, to analyze the atomic mobility in amorphous materials, a physical theory is introduced. This model invokes the concept of quasi-point defects, which correspond to the density fluctuations in the glassy materials.

关键词： Metallic glasses Mechanical properties Main relaxation Secondary relaxation Physical analysis

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Exploration of cobalt selenite-carbon composite porous nanofibers as anode for sodium-ion batteries and unveiling their conversion reaction mechanism

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journal of Materials Science & Technology 2021年第30期89卷 24-35页

作者： jin-Sung park Gi Dae park Yun chan Kang Department of Materials Science and Engineering Korea UniversityAnam-DongSeongbuk-GuSeoul136-713Republic of Korea

Efforts have been made to develop a promising anode material with a novel composition for sodiumion batteries(SIBs).In this study,the sodium-ion storage mechanism of transition metal selenite that comprises transition metal cation coupled with two anions is *** cobalt selenite(coSeO_(3))-carbon composite nanofibers containing numerous pores are synthesized via electrospinning *** heat treatment of the electrospun nanofibers containing selenium,coSe_(2)nanoclusters are *** the subsequent oxidation,coSe_(2)transformed into amorphous coSeO_(3)and some part of carbon was oxidized into cO_(2),leaving the pores inside the *** unveil the electrochemical reaction mechanism,analytical methods including cyclic voltammetry,ex-situ X-ray photoelectron spectroscopy,ex-situ transmission electron microscopy,and in-situ electrochemical impedance spectroscopy techniques were *** on the analyses,the following conversion reaction from the second cycle onward is suggested:coO+xSeO_(2)+(1-x)Se+4(x+1)Na^(+)+4(x+1)e~-?co+(2x+1)Na_(2)O+Na_(2)***,the electrochemical properties of porous coSeO_(3)-carbon composite nanofibers are analyzed in *** anode material exhibited stable cycle stability up to 200 cycles at 0.5 A g^(-1)and high rate performance up to 5 A g^(-1).

关键词： Anode materials Sodium-ion batteries conversion reaction Metal selenite Electrospinning

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Density functional theory study on the role of ternary alloying elements in TiFe-based hydrogen storage alloys

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journal of Materials Science & Technology 2021年第33期92卷 148-158页

作者： Won-Seok Ko Ki Beom park Hyung-Ki park School of Materials Science and Engineering University of UlsanUlsan 44610Republic of Korea Functional Materials and components R&D Group Korea Institute of Industrial TechnologyGangneung 25440Republic of Korea

The role of additional ternary alloying elements on the performance of stationary TiFe-based hydrogen storage alloys was investigated based on first-principles density functional theory *** a basic step for examinations,the site preference of each alloying element in the stoichiometric and nonstoichiometric B2TiFe compounds was clarified considering possible antisite *** on the revealed site preference,the effect of various possible ternary elements on the hydrogen storage was examined by focusing on the formation enthalpies of TiFeH and TiFeH_(2) hydrides,which were closely related to the change in the location of plateaus in the pressure-composition-temperature *** physical properties such as the volume expansion due to hydride formation were also examined to provide additional criteria for selecting optimum alloying conditions in future alloying design *** alloying elements that maximize the grain boundary embrittlement due to the solute segregation were proposed for the enhanced initial activation of TiFe-based hydrogen storage alloys.

关键词： Hydrogen storage alloy Titanium-iron Density functional theory calculation Metallic hydride

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The Kirkendall effect on erosion resistance of chrome-coated 25cr3Mo2WNiV and 30SiMn2MoV gun barrel steels

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journal of Materials Science & Technology 2024年第10期177卷 246-255页

作者： c.H.Dou P.F.jin c.Z.Wang j.j.Li c.Zhang j.F.Huang c.Zhang Key Laboratory for Advanced Materials Processing State State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China National joint Engineering Research center for Abrasion control and Molding of Metal Materials School of Materials Science and EngineeringHenan University of Science and TechnologyLuoyang 471003China

This study aimed to investigate the erosion behavior and mechanism of a newly developed 25cr3Mo2WNiV steel with a chrome coating using promoted ignition combustion *** erosion threshold pressure and temperature of the chrome-coated 25cr3Mo2WNiV steel were determined to be 0.2 MPa and 254.3 K higher than those of traditional chrome-coated 30SiMn2MoV ***,Kirkendall voids and inter-diffusion between the cr coating and matrix were first observed before *** improved erosion resistance of the chrome-coated 25cr3Mo2WNiV steel was attributed to the suppression of the Kirkendall effect,which minimized heat generation at the cr/matrix interface by pre-venting oxygen diffusion and reducing oxygen affinity.

关键词： Erosion resistance Kirkendall effect cr coating Gun steel

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