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Potential Alzheimer’s disease therapeutic nano-platform: Discovery of amyloid-beta plaque disaggregating agent and brain-targeted delivery system using porous silicon nanoparticles

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Bioactive Materials 2023年第6期24卷 497-506页

作者： Jaehoon kim Hyeji Um Na Hee kim Dokyoung kim Department of Biomedical Science Graduate SchoolKyung Hee UniversitySeoul02447Republic of Korea Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute Kyung Hee UniversitySeoul02447Republic of Korea Department of Anatomy and Neurobiology College of MedicineKyung Hee UniversitySeoul02447Republic of Korea Center for Converging Humanities Kyung Hee UniversitySeoul02447Republic of Korea KHU-KIST Department of Converging Science and Technology Kyung Hee UniversitySeoul02447Republic of Korea UC San Diego Materials Research Science and Engineering Center 9500 Gilman Drive La JollaCA92093USA

There has been a lot of basic and clinical research on Alzheimer’s disease(AD)over the last 100 years,but its mechanisms and treatments have not been fully *** some controversies,the amyloid-beta hypothesis is one of the most widely accepted causes of *** this study,we disclose a new amyloid-beta plaque disaggregating agent and an AD brain-targeted delivery system using porous silicon nanoparticles(pSiNPs)as a therapeutic nano-platform to overcome *** hypothesized that the negatively charged sulfonic acid functional group could disaggregate plaques and construct a chemical *** a result of the in vitro assay of amyloid plaques and library screening,we confirmed that 6-amino-2-naphthalenesulfonic acid(ANA)showed the highest efficacy for plaque disaggregation as a hit *** confirm the targeted delivery of ANA to the AD brain,a nano-platform was created using porous silicon nanoparticles(pSiNPs)with ANA loaded into the pore of pSiNPs and biotin-polyethylene glycol(PEG)surface *** resulting nano-formulation,named Biotin-CaCl2-ANA-pSiNPs(BCAP),delivered a large amount of ANA to the AD brain and ameliorated memory impairment of the AD mouse model through the disaggregation of amyloid plaques in the *** study presents a new bioactive small molecule for amyloid plaque disaggregation and its promising therapeutic nano-platform for AD brain-targeted delivery.

关键词： Alzheimer’s disease Plaques disaggregation Nanotherapeutics Brain-targeted drug delivery Porous silicon nanoparticles

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Failure Modes of Lead Free Solder Bumps Formed by Induction Spontaneous Heating Reflow

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Journal of Materials Science & Technology 2007年第1期23卷 61-67页

作者： Mingyu LI Hongbo XU Jongmyung kim Hongbae kim Shenzhen Graduate School Harbin Institute of Technology Shenzhen 518055 China Jeonnam Provincial College Jeonnam 517-802 Korea

The shear failure modes and respective failure mechanism of Sn3.5Ag and Sn3.0Ag0.5Cu lead-free solder bumping on Au/Ni/Cu metallization formed by induction spontaneous heating reflow process have been investigated through the shear test after aging at 120℃ for 0, 1, 4, 9 and 16 d. Different typical shear failure behaviors have been found in the loading curves （shear force vs displacement）. From the results of interracial morphology analysis of the fracture surfaces and cross-sections, two main typical failure modes have been identified. The probabilities of the failure modes occurrence are inconsistent when the joints were aged for different times. The evolution of the brittle NiaSn4 and Cu-Ni-Au-Sn layers and the grains coarsening of the solder bulk are the basic reasons for the change of shear failure modes.

关键词： Induction spontaneous heating reflow Lead free solder Shear test Failure mode

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Phylogenetic relationship,biogeography,and conservation genetics of endangered Fraxinus chiisanensis(Oleaceae),endemic to South Korea

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Plant Diversity 2022年第2期44卷 170-180页

作者： Changkyun kim Dong-Kap kim Hang Sun Joo-Hwan kim Plant Research Division Honam National Institute of Biological ResourcesMokpo 58762Republic of Korea Forest Biodiversity Division Korea National ArboretumPocheon 11186Republic of Korea CAS Key Laboratory for Plant Biodiversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650204YunnanPR China Department of Life Science Gachon UniversitySeongnam 13120Republic of Korea

Endemic plants are important for understanding phylogenetic relationships,biogeographical history,and genetic variation because of their restricted distribution and their role in conserving ***,we investigated the phylogenetic relationships of the Korean endemic Fraxinus chiisanensis by reconstructing the molecular phylogeny of Fraxinus based on two nuclear DNA(nrITS and phantastica)and two chloroplast DNA(psbA-trnH and rp132-trnL)*** our fossil-calibrated phylogenetic framework,we also inferred the biogeographical history of *** provide a scientific basis for the conservation of ***,we determined the levels of genetic diversity and genetic differentiation in this *** information from nuclear and chloroplast DNA sequence data,our molecular phylogenetic analyses identified *** as a genetically distinct unit from its sister group,Fraxinus platypoda from *** molecular dating analyses using nuclear and chloroplast DNA data sets show *** diverged from its sister *** in the Early or Middle Miocene and differentiated in the Late Miocene on the Korean *** results suggest that the divergence of *** was associated with the submergence of the East China Sea land bridge and enhanced monsoons in East *** compared to ***,*** exhibits low genetic diversity within populations and high genetic differentiation among *** results help us to understand the evolutionary history of *** and to develop a conservation strategy for this species.

关键词： East China Sea land bridge Endemic species Fraxinus chiisanensis Korean Peninsula Genetic diversity Biogeography

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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

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Global Existence of Smooth Solutions for the Diffusion Approximation Model of General Gas in Radiation Hydrodynamics

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Acta Mathematica Sinica,English Series 2023年第10期39卷 1855-1873页

作者： Hyejong kim Hakho HONG Jongsung kim Graduate School Kim Hyong Jik University of EducationPyongyangDemocratic People’s Republic of Korea Institute of Mathematics State Academy of SciencesPyongyangDemocratic People’s Republic of Korea School of Mathematics University of Mechanical Engineering PyongyangPyongyangDemocratic People’s Republic of Korea

In this paper,we consider the 3-D Cauchy problem for the diffusion approximation model in radiation *** existence and uniqueness of global solutions is proved in perturbation framework,for more general gases including ideal poly tropic ***,the optimal time decay rates are obtained for higher-order spatial derivatives of density,velocity,temperature,and radiation field.

关键词： Radiation hydrodynamics diffusion approximation model existence convergence rate

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Supersonic Cavity Based Combustion with Kerosene/Hydrogen Fuel

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Journal of Thermal Science 2015年第2期24卷 164-172页

作者： Rajarshi Das Jeong Soo kim Heuy Dong kim Department of Mechanical Engineering Andong National University School of Mechanical Engineering Pukyong National University

A comparative study with kerosene and hydrogen fuel in a model scramjet combustor has been carried out nu- merically. The effect of fuel-air equivalence ratio on the flow field properties in a cavity based mixing mechanism at a freestream Math number of 2.08 has been probed. The investigation has been carried out in a two dimension- al numerical model where a cavity of length to depth ratio of 2 is mounted on one of the walls of the flow channel The flow field shock structure is observed to change with the change in fuel-air equivalence ratio. Total pressure loss is observed to depend both on fuel air equivalence ratio and the fuel type. The spread of fuel in the test sec- tion shows marked variation with the equivalence ratio. Performance of injector location on the fuel-air mixing is also probed during the course of the investigation.

关键词： Scramjet fuel-air mixing kerosene hydrogen equivalence ratio

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Effect of partial elastic foundation on free vibration of fluid-filled functionally graded cylindrical shells

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Acta Mechanica Sinica 2015年第6期31卷 920-930页

作者： Young-Wann kim Department of Mechanical Design Engineering Chonnam National University

The free vibration characteristics of fluid-filled functionally graded cylindrical shells buried partially in elas- tic foundations are investigated by an analytical method. The elastic foundation of partial axial and angular dimen- sions is represented by the Pasternak model. The motion of the shells is represented by the first-order shear defor- mation theory to account for rotary inertia and transverse shear strains. The functionally graded cylindrical shells are composed of stainless steel and silicon nitride. Material prop- erties vary continuously through the thickness according to a power law distribution in terms of the volume fraction of the constituents. The governing equation is obtained using the Rayleigh-Ritz method and a variation approach. The fluid is described by the classical potential flow theory. Numerical examples are presented and compared with existing available results to validate the present method.

关键词： Functionally graded material· Fluid-filledshell· Pasternak elastic foundation · Vibration

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New Precoded Spatial-Multiplexing for an Erasure Event in Single Frequency Networks

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China Communications 2018年第4期15卷 130-140页

作者： hojun kim seyoung kim yulong shang seunghyeon kim taejin jung Department of Electronics and Computer Engineering Chonnam National University Gwangju 61186 Republic of Korea R＆D Planning and Management Team Giga KOREA Foundation Daejcon 34054 Republic of Korea

In this paper, we propose a new spatial-multiplexing(SM) scheme employing an orthogonal precoder over Rayleigh-fading channels for an erasure event in single frequency networks(SFN). To optimize the precoder, the average bit error rate(BER) is evaluated and minimized through a mathematical analysis. Compared to an ordinary SM, the proposed scheme guarantees identical BER performance under non-erasure fading channels and achieves a greatly improved performance under erasure fading channels, especially for a higher erasure-ratio and SNR values. This improvement is mainly due to the increase in the diversity gain incurred by the optimized precoder over the erasure event. We also compare the performance of the proposed SM to that of the conventional constellation-rotation(CR) scheme applied to the single antenna SFN systems. The results of a computer simulation show that the performance of the new scheme is more effective than that of a conventional CR across all simulation cases.

关键词： Spatial-multiplexing single fre-quency network Rayleigh fading constella-tion-rotation broadcasting systems.

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Feasibility of wear reduction for soft nanostructured thin film through enhanced elastic recoverability and contact stress relief

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Friction 2023年第7期11卷 1292-1306页

作者： Kuk-Jin SEO Hyun-Joon kim Dae-Eun kim Department of Mechanical Engineering Yonsei UniversitySeoul 03722Republic of Korea Department of Precision Mechanical Engineering Kyungpook National UniversitySangju 37224Republic of Korea Department of Advanced Science and Technology Convergence Kyungpook National UniversitySangju 37224Republic of Korea

This work shows that a soft,thin film comprising randomly aligned carbon nanotubes(CNTs)can reduce surface wear more effectively than a homogeneous thin film because of enhanced elastic recoverability and contact stress relief originating from its mesh *** investigate the wear characteristics of the mesh structure compared to those of the homogeneous thin film,multi-walled CNTs(MWCNTs)and diamond-like carbon(DLC)thin films were prepared to conduct nanoscale tribological experiments using the atomic force microscopy(AFM).The MWCNT thin film showed unmeasurably low wear compared with the DLC thin film under a certain range of normal *** demonstrate the wear reduction mechanism of the MWCNT thin film,its indentation and frictional behaviors were *** indentation behavior of the MWCNT thin film revealed repetitive elastic deformation with a wide strain range and a significantly lower elastic modulus than that of the DLC thin *** permanent deformation of the MWCNT thin film was observed through frictional experiments under relatively high normal load *** results are expected to provide insights into the design of highly wear-resistant surfaces using nanostructures.

关键词： carbon nanotube(CNT) thin film wear friction elastic recovery

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Characteristics analysis and library development for piezoelectric transformer to drive a ballast for a 35 W class fluorescent lamp using PSPICE modeling

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Journal of Central South University 2016年第1期23卷 169-180页

作者： kim Young-Choon Division of Mechanical and Automotive Engineering College of Engineering Kongju National University

PSPICE model driven by an electric equivalent circuit of a piezoelectric circuit is presented. In order to confirm this model to be effective, an independent model of cold cathode fluorescent lamp(CCFL) driving circuit is used to conduct simulations, leading to a precise modeling. A library is configured through modeling and its accuracy is verified through simulations for widely used and representative lamps such as CCFL, fluorescent lamps, HID lamps, and electrodeless fluorescent lamps. On the basis of experiments, a lamp simulation is also performed using PSPICE, which allows us to take advantage of the lamp library easily. Also, PSPICE model driven by an electric equivalent circuit of a piezoelectric transformer is presented. In order to confirm this model to be effective, an independent model of CCFL driving circuit is used to conduct simulations, leading to a precise modeling. In addition, a new type of electronic ballast is proposed, which allows 35 W-class(T5-class) fluorescent lamp to work. This system is built by a rectifier which has improved power factor and half-bridge series resonant inverter. Also, with size of 27.5 mm high, 27.5 mm wide and 2.5 mm thick, the produced piezoelectric transformer has a high step-up ratio, through which it is possible for the electric ballast circuit to be lighter, smaller and more efficient. After the produced ballast is used to drive the fluorescent lamp for 25 min, it yields 0.95 in power factor correction, 86% in efficiency, 35.07 W in output voltage and 20.5 °C in temperature increase while meeting the characteristics of the 35 W-class fluorescent lamp.

关键词： PSPICE 35 W-class cold cathode fluorescent lamp (CCFL) fluorescent lamp library

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