The Capability of Catabolic Utilization of N-Acetylneuraminic Acid, a Sialic Acid, Is Essential for Vibrio vulnificus Pathogenesis

Jeong, Hee Gon,Oh, Man Hwan,Kim, Byoung Sik,Lee, Min Young,Han, Ho Jae,Choi, Sang Ho American Society for Microbiology 2009 Infection and immunity Vol.77 No.8

<B>ABSTRACT</B><P><I>N</I>-acetylneuraminic acid (Neu5Ac, sialic acid) could provide a good substrate for enteropathogenic bacteria in the intestine, when the bacteria invade and colonize in human gut. In order to analyze the role of Neu5Ac catabolism in <I>Vibrio vulnificus</I> pathogenesis, a mutant with disruption of the <I>nanA</I> gene encoding Neu5Ac lyase was constructed by allelic exchanges. The <I>nanA</I> mutant was not able to utilize Neu5Ac as a sole carbon source and revealed an altered colony morphotype with reduced opacity in the presence of Neu5Ac. Compared to the wild type, the <I>nanA</I> mutant exhibited a low level of cytotoxicity toward INT-407 epithelial cells in vitro and reduced virulence in a mouse model. The disruption of <I>nanA</I> also resulted in a substantial decrease in histopathological damage in jejunum and colon tissues from the mouse intestine. These results indicated that NanA plays an important role in <I>V. vulnificus</I> pathogenesis. In addition, the <I>nanA</I> mutant was significantly diminished in growth with and adherence to INT-407 epithelial cells in vitro, and was defective for intestinal colonization, reflecting the impaired ability of the mutant to grow and survive with, persist in, and adhere to the intestine in vivo. Consequently, the combined results suggest that NanA and the capability of catabolic utilization of Neu5Ac contribute to <I>V. vulnificus</I> virulence by ensuring growth, adhesion, and survival during infection.</P>

A Travelling Control of Mobile Robot Based on Sonar Sensors

Byoung-Kyun Shim,Jun-Seok Yang,Eok-Gon Kim,Yang-Keun Jeong,Jong Bum Won,Sung-Hyun Han 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10

Automotive Body Design

Jeong-Ick Lee(이정익),Byoung-Gon Kim(김병곤),Tae-Jin Chung(정태진) 한국생산제조학회 2008 한국생산제조학회지 Vol.17 No.5

In an automotive body structure, a design configuration that fulfills structural requirements such as deflection, stiffness and strength is necessary for structural design and is composed of various components. The integrated design is used to obtain a minimum weight structure with optimal or feasible performance based on conflicting constraints and boundaries. The mechanical design must begin with the definition of one or more concepts for structure and specification requirements in a given application environment. Structural optimization is then introduced as an integral part of the product design and used to yield a superior design to the conventional linear one. Although finite element analysis has been firmly established and extensively used in the past, geometric and material nonlinear analyses have also received considerable attention over the past decades. Also, nonlinear analysis may be useful in the area of structural designs where instability phenomena can include critical design criteria such as plastic strain and residual deformation. This proposed approach can be used for complicated structural analysis for an integrated design process with the nonlinear feasible local flexibilities between system and subsystems.

Fabrication of Calcined Clay Granule Comprising Zeolite

Byoung-Gon Kim(김병곤),Gye-Seung Lee(이계승),Chong-Lyuck Park(박종력),Ho-Seok Jeon(전호석),Soo-Bok Jeong(정수복) 한국토양비료학회 2008 한국토양비료학회지 Vol.41 No.4

제올라이트는 높은 양이온교환능력(CEC)으로 인해 토양개량제의 사용이 고려되어 왔으나, 이에 관한 연구들의 대부분이 제올라이트를 합성하거나 천연제올라이트의 CEC를 증가시키는데 국한되어왔다. 실제로 제올라이트를 토양개량제로 사용하기 위해서는 유실되는 것을 방지하기 위한 과립화 (granulation or pelletizing)가 요구된다. 본 연구는 제올라이트를 토양개량제로 활용하기 위해 이를 포함하는 소성점토의 과립 (calcined clay granule)을 제조하고, 제올라이트의 특성을 최대로 활용할 수 있는 과립의 제조조건을 찾으려 하였다. 천연제올라이트, 고령토, 규석을 재료로 하여, pan granulator와 high shear mixer granulator의 두가지 과립기를 사용하여 과립을 제조하였다. 재료의 혼합비와 과립기의 회전속도 등을 조절하여 과립을 제조하였으며, 이를 400~700℃범위에서 100℃단위로 소성한 후 파쇄강도 (crushing strength), 기공분포 (pore distribution), CEC를 측정하였다. 토양개량제로 사용할 과립은 취급시에 요구되는 기본적인 강도뿐만 아니라 토양과 혼합된 후 답압(踏壓)에 견디기 위한 강도 또한 요구된다. 본 연구에서는 과립의 답압에 관한 저항성 평가방법을 마련하고, 마른 상태와 젖은 상태에서 과립의 저항성을 측정하였다. 과립기의 회전속도와 가열온도에 비례하여 답압에 대한 저항성은 증가하나 CEC는 감소하였다. Pan granulator는 700℃이하의 가열에서 적절한 강도를 갖는 과립을 제조할 수 없었으나, high shear mixer granulator는 500℃이상의 가열에 의해 답압에 저항성을 갖는 과립을 제조할 수 있었다. This research tried to find out the optimum fabrication method of calcined clay granules comprising zeolite. Kaolin clay and natural zeolite powder were used as raw materials of calcined clay, and silica stone powder was used for controlling the porosity of the granules. The granulation was performed with two kinds of granulators: a pan granulator and a high-shear mixer granulator. Various granules were fabricated by the mixing ratios and the rotation speeds of the granulators, and were heated from 400 to 700℃ at 100℃ interval. The crushing strength, pore size distribution, and CEC of the granules were measured. The evaluation method for the resistance of granules to human treading was created and the tests were conducted at dry and wet conditions. The resistance and crushing strength improved in proportion to the rotation speed of the granulator and the heating temperature, but the CEC decreased. The pellet made by the pan granulator did not have the strength against treading upon heating to below 700℃, but the pellet made by the high-shear mixer granulator endured the treading test upon heating to over 500℃

Pareto Optimal Design of the Vehicle Body

Byoung-Gon Kim(김병곤),Tae-Jin Chung(정태진),Jeong-Ick Lee(이정익) 한국생산제조학회 2008 한국생산제조학회지 Vol.17 No.4

The important dynamic specifications in the aluminum automobile body design are the vibrations and crash worthiness in the views of ride comforts and safety. Thus, considerable effort has been invested into improving the performance of mechanical structures comprised of the interactive multiple sub-structures. Most mechanical structures are complex and are essentially multi-criteria optimization problems with objective functions retained as constraints. Each weight factor can be defined according to the effects and priorities among objective functions, and a feasible Pareto-optimal solution exists for the criteria-defined constraints. In this paper, a multi-criteria design based on the Pareto-optimal sensitivity is applied to the vibration qualities and crushing characteristics of front structure in the automobile body design. The vibration qualities include the idle, wheel unbalance and road shake. The crushing characteristic of front structure is the axial maximum peak load.

Reversibly Stretchable, Optically Transparent Radio-Frequency Antennas Based on Wavy Ag Nanowire Networks

Kim, Byoung Soo,Shin, Keun-Young,Pyo, Jun Beom,Lee, Jonghwi,Son, Jeong Gon,Lee, Sang-Soo,Park, Jong Hyuk American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.4

<P>We report a facile approach for producing reversibly stretchable, optically transparent radio-frequency antennas based on wavy Ag nanowire (NW) networks. The wavy configuration of Ag NWs is obtained by floating the NW networks on the surface of water, followed by compression. Stretchable antennas are prepared by transferring the compressed NW networks onto elastomeric substrates. The resulting antennas show excellent performance under mechanical deformation due to the wavy configuration, which allows the release of stress applied to the NWs and an increase in the contact area between NWs. The antennas formed from the wavy NW networks exhibit a smaller return loss and a higher radiation efficiency when strained than the antennas formed from the straight NW networks, as well as an improved stability in cyclic deformation tests. Moreover, the wavy NW antennas require a relatively small quantity of NWs, which leads to low production costs and provides an optical transparency. These results demonstrate the potential of these wavy Ag NW antennas in applications of wireless communications for wearable systems.</P>

지그비 기반의 센서 네트워크에서 Gaussian Filtering 기법을 적용한 위치 추적 향상 기법

허병회(Byoung-hoe Hur),김정곤(Jeong-Gon Kim) 한국통신학회 2009 韓國通信學會論文誌 Vol.34 No.12

2D reentrant auxetic structures of graphene/CNT networks for omnidirectionally stretchable supercapacitors

Kim, Byoung Soo,Lee, Kangsuk,Kang, Seulki,Lee, Soyeon,Pyo, Jun Beom,Choi, In Suk,Char, Kookheon,Park, Jong Hyuk,Lee, Sang-Soo,Lee, Jonghwi,Son, Jeong Gon Royal Society of Chemistry 2017 Nanoscale Vol.9 No.35

<P>Stretchable energy storage systems are essential for the realization of implantable and epidermal electronics. However, high-performance stretchable supercapacitors have received less attention because currently available processing techniques and material structures are too limited to overcome the trade-off relationship among electrical conductivity, ion-accessible surface area, and stretchability of electrodes. Herein, we introduce novel 2D reentrant cellular structures of porous graphene/CNT networks for omnidirectionally stretchable supercapacitor electrodes. Reentrant structures, with inwardly protruded frameworks in porous networks, were fabricated by the radial compression of vertically aligned honeycomb-like rGO/CNT networks, which were prepared by a directional crystallization method. Unlike typical porous graphene structures, the reentrant structure provided structure-assisted stretchability, such as accordion and origami structures, to otherwise unstretchable materials. The 2D reentrant structures of graphene/CNT networks maintained excellent electrical conductivities under biaxial stretching conditions and showed a slightly negative or near-zero Poisson's ratio over a wide strain range because of their structural uniqueness. For practical applications, we fabricated all-solid-state supercapacitors based on 2D auxetic structures. A radial compression process up to 1/10<SUP>th</SUP>densified the electrode, significantly increasing the areal and volumetric capacitances of the electrodes. Additionally, vertically aligned graphene/CNT networks provided a plentiful surface area and induced sufficient ion transport pathways for the electrodes. Therefore, they exhibited high gravimetric and areal capacitance values of 152.4 F g<SUP>−1</SUP>and 2.9 F cm<SUP>−2</SUP>, respectively, and had an excellent retention ratio of 88% under a biaxial strain of 100%. Auxetic cellular and vertically aligned structures provide a new strategy for the preparation of robust platforms for stretchable energy storage electrodes.</P>

Biaxial Stretchability and Transparency of Ag Nanowire 2D Mass-Spring Networks Prepared by Floating Compression

Kim, Byoung Soo,Pyo, Jun Beom,Son, Jeong Gon,Zi, Goangseup,Lee, Sang-Soo,Park, Jong Hyuk,Lee, Jonghwi American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.12

<P>Networks of silver nanowires (Ag NWs) have been considered as promising materials for stretchable and transparent conductors. Despite various improvements of their optoelectronic and electromechanical properties over the past few years, Ag NW networks with a sufficient stretchability in multiple directions that is essential for the accommodation of the multidirectional strains of human movement have seldom been reported. For this paper, biaxially stretchable, transparent conductors were developed based on 2D mass-spring networks of wavy Ag NWs. Inspired by the traditional papermaking process, the 2D wavy networks were produced by floating Ag NW networks on the surface of water and subsequently applying biaxial compression to them. It was demonstrated that this floating-compression process can reduce the friction between the Ag NW-water interfaces, providing a uniform and isotropic in-plane waviness for the networks without buckling or cracking. The resulting Ag NW networks that were transferred onto elastomeric substrates successfully acted as conductors with an excellent transparency, conductivity, and electromechanical stability under a biaxial strain of 30%. The strain sensors that are based on the prepared conductors demonstrated a great potential for the enhanced performances of future wearable devices.</P>

Sub‐10 nm Graphene Nanoribbon Array Field‐Effect Transistors Fabricated by Block Copolymer Lithography

Son, Jeong Gon,Son, Myungwoo,Moon, Kyeong‐,Joo,Lee, Byoung Hun,Myoung, Jae‐,Min,Strano, Michael S.,Ham, Moon‐,Ho,Ross, Caroline A. WILEY‐VCH Verlag 2013 ADVANCED MATERIALS Vol.25 No.34

<P><B>Sub‐10 nm Graphene Nanoribbon Arrays</B> are fabricated over large areas by etching CVD‐grown graphene. A mask is used made by the directed self‐assembly of a cylindrical PS‐<I>b</I>‐PDMS block copolymer under solvent annealing guided by a removable template. The optimized solvent annealing process, surface‐modified removable polymeric templates, and high Flory‐Huggins interaction parameters of the block copolymer enable a highly aligned array of nanoribbons with low line edge roughness to be formed. This leads to a higher on/off ratio and stronger temperature dependence of the current for nanoribbon FETs, and a photocurrent which is 30 times larger compared to unpatterned graphene.</P>