Dong Hun Shin

Hallym University Medical Center, Sŏul, Seoul, South Korea

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Publications (20)41.14 Total impact

  • Young Gun Ko · Dong Hun Shin · Gil Sun Lee · Ung Su Choi
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    ABSTRACT: Herein, we demonstrate the structure of the PS colloidal crystals which were fabricated on the hydrophilic/hydrophobic Si wafers by a spin-coating technique. Monodisperse PS colloids are spin-coated onto self-assembled monolayers of 3-(aminopropyl)triethoxysilane and propyltrimethoxysilane coated Si wafers. PS spheres organized as ordered close-packed face-centered cubic structure with (1 1 1) planes on the hydrophilic surface while they gathered without the crystal structure on the hydrophobic surface. This paper also reports a simple and rapid method to fabricate the close-packed structure of hollow TiO2 spheres. The colloidal crystal of TiO2 hollow spheres was prepared using the PS sphere template on the hydrophobic surface. The mechanism for the growing multilayers of self-assembled PS particles from a suspension onto a hydrophilic and hydrophobic Si wafer substrates using the spin-coating method at various rotating speeds is also discussed in this paper.Graphical abstractThe TiO2 inverse opals were fabricated using the PS opal templates which were prepared on the hydrophilic and the hydrophobic surfaces by the spin-coating method.Highlights► PS colloidal crystals were fabricated on the hydrophilic and the hydrophobic surfaces by spin-coating. ► The structure of the spin-coated PS colloidal crystals depended on the surface wettability. ► The mechanism for the growing multilayers of self-assembled spheres by the spin-coating method is discussed. ► This work demonstrates the rapid and simple method for the fabrication of colloidal crystal of TiO2 hollow spheres.
    No preview · Article · Jul 2011 · Colloids and Surfaces A Physicochemical and Engineering Aspects
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    ABSTRACT: A study using boronic acid (BA), an AmpC enzyme inhibitor, was designed to detect the combined expression of plasmid-mediated AmpC beta-lactamases (pAmpCs) and extended-spectrum beta-lactamases (ESBLs) in bacterial isolates naturally lacking chromosomal ampC genes. A total of 122 Klebsiella spp., Salmonella spp., and Proteus mirabilis isolates producing or nonproducing pAmpCs and/or ESBLs were analyzed. Detection of genes encoding ESBLs and AmpCs was confirmed by polymerase chain reaction (PCR) followed by sequencing of PCR products. A > or = 5-mm increase in zone diameter for i) cefoxitin (FOX) and/or cefotetan (CTT) containing BA versus FOX and/or CTT alone was considered positive for AmpC; ii) ceftazidime (CAZ)-clavulanate (CA) and/or cefotaxime (CTX)-CA tested in combination with BA versus CAZ and/or CTX containing BA was considered positive for ESBL. The disk tests of FOX and/or CTT alone and with BA detected 98.4% of organisms producing pAmpCs. All of the 21 pAmpC and ESBL coproducers were accurately detected ESBL by the disk tests of CTX-CA and/or CAZ-CA containing BA and CTX and/or CAZ containing BA. In conclusion, The BA disk test using Clinical and Laboratory Standards Institute methodology is simple and very efficient method to detect pAmpC and ESBL in organisms naturally lacking chromosomal AmpC enzymes. In particular, the method accurately detects the isolates that harbor both AmpCs and ESBLs.
    Full-text · Article · Mar 2007 · Diagnostic Microbiology and Infectious Disease
  • Young Gun Ko · Dong Hun Shin
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    ABSTRACT: For the application of colloidal crystal films as "photonic band gap" materials, their domain size and thickness are significant. The substrate withdrawing speed, the colloidal suspension volume fraction, and the colloidal suspension temperature have been studied for the domain size and thickness controls of colloidal crystals in this study. Stable dispersions of monodispersed polystyrene spheres with a diameter of 245 nm were synthesized according to a general emulsion polymerization for colloidal crystal films. By experimental results and the theoretical relationship between the number of layers and other parameters, we could know that the water bridge between colloidal spheres (which is formed by capillary force) influences the number of colloidal crystal layers significantly.
    No preview · Article · Mar 2007 · The Journal of Physical Chemistry B
  • Yu-Jin Kim · Dong Hun Shin
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    ABSTRACT: The clean tube system was developed as a means of transferring air-floated wafers inside a closed tube filled with super clean air. This paper presents a wafer motion sensing and control methods in the clean tube system, where the photo proximity sensors are used. The first presented method uses the two positions sensed lately in order to compute the wafer center position. The next method uses the latest sensed position and the next latest position compensated with the information of the wafer velocity. The third method uses the Kalman filter, which enable us to use all the previous sensing information. The simulation results are compared to show results of the presented methods. Tn addition, the paper presents a control method to stop the wafer at the center of the unit in the clean tube system. The experimental clean tube system worked successfully with the applying the both presented methods of sensing and control.
    No preview · Article · Nov 2006
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    ABSTRACT: Parkinsonian syndromes associated with basal ganglia pathology have very rarely been reported in patients with end-stage renal failure. The nature and pathophysiology of the basal ganglia lesion responsible for parkinsonism were unknown. A 48-year-old man who had advanced renal failure developed disturbance of balance and gait and decreased spontaneity. Brain magnetic resonance (MR) imaging disclosed bilateral basal ganglia lesions. By the finding of diffusion-weighted image, the apparent diffusion coefficient map, MR angiography, and SPECT, we suggest that the basal ganglia lesions may be the result of vasogenic edema attributable to focal hyperemia secondary to abnormal dilatation of small vessels.
    No preview · Article · Apr 2006 · Parkinsonism & Related Disorders
  • Dong Hun Shin · Young Gun Ko · Ung Su Choi · Woo Nyon Kim
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    ABSTRACT: A unique chemosensor for Ag ions was created by coupling an anthracene signaling unit onto an amine-terminated glass slide. Chemical dye (Orange 11) was applied to establish the exposed amine groups on the surface, because the coupling reaction is dependent on the amount of the exposed amine groups. The assembled layer had a surface that was not flat but, instead, had an embossed shape, on the microscale; the surface roughness was greater than that of the original glass, because of the morphology of the rare glass. The quenching effect of the synthesized chemosensor is notable in Ag aqueous solution, despite concentrations on the parts per billion (ppb) scale. When several Ag ions were provided for the chemosensor, the morphology of the chemosensor was considerably changed, which made the contact angles change. All the states of the chemosensor in the surface were characterized using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The bowing effect and binding state, in regard to the adsorption of Ag ions, were further specified using X-ray photoelectron spectroscopy (XPS).
    No preview · Article · Jan 2006 · Industrial & Engineering Chemistry Research
  • Young Gun Ko · Dong Hun Shin · Ung Su Choi
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    ABSTRACT: Field-emission scanning electron microscopy (FESEM) was used to monitor pinecone-like Cu(II) crystal growth on polymeric fibers for various growth times. In FESEM images, Cu(II) complexes and Cu(OH)2 crystal growth on poly(acryloamidino ethylene amine) and poly(acryloamidino diethylenediamine) were observed. Up to an elapsed time of 16 min, crystal growth was observed in only one direction. However, after an elapsed time of 20 h, pinecone-like crystals covered the entire surfaces of the synthesized polymers. Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were used for analysis. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1238–1247, 2005
    No preview · Article · Mar 2005 · Journal of Polymer Science Part A Polymer Chemistry
  • Dong Hun Shin · Young Gun Ko · Ung Su Choi · Woo Nyon Kim
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    ABSTRACT: A polyacrylonitrile (PAN) fiber was adopted for the backbone of a chelate polymer and poly(acrylo-amidino ethylene amine) (PAEA) was prepared through a one-step reaction between the PAN fiber and ethylenediamine (EDA). The maximum removal capacity and degree of substitution were 7.8 meq per gram of dried PAEA and 98%, respectively. The PAEA was tested as an adsorbent in single and two-component metal aqueous solutions under changing pH. The Cu2+ ion accomplished maximum adsorption amount at pH 3 and the order of maximum adsorbed amounts on PAEA is Cu2+ > Ag+ > Zn2+ > Ni2+ > Pb2+ in molar basis. FT-IR spectroscopy was employed to characterize the chemical bonding in metal aqueous solutions and surface morphology was examined using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Copyright © 2004 John Wiley & Sons, Ltd.
    No preview · Article · Aug 2004 · Polymers for Advanced Technologies
  • Young Gun Ko · Dong Hun Shin · Ung Su Choi
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    ABSTRACT: Poly(acryloamidino ethyleneamine) (PAEA) and poly(acryloamidino diethylene diamine) (PADD) have been synthesized for the observation of CuII complex and Cu(OH)2 crystal-growth on the surface of different numbers of amino groups immobilized on polyacrylonitrile (PAN) fibers. The shape of CuII crystal growth depends on the amine chain length of the chelating fiber; Cu(OH)2 crystals grow on the surface of the chelating fiber after CuII adsorption.
    No preview · Article · Jul 2004 · Macromolecular Rapid Communications
  • Dong Hun Shin · Young Gun Ko · Ung Su Choi · Woo Nyon Kim
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    ABSTRACT: We have been searching a new ion exchange material in the form of a fiber which could get large advantages over the conventional bead type. In this approach, an effective chelating fiber is prepared by the coupling of polyacrylonitrile (PAN) and ethylenediamine. A synthesized ion exchange fiber (poly(acrylo-amidino ethylene amine), PAEA) achieved 7.8 mequiv/g of adsorption capacity in a batch test. The coupling process and capacity were confirmed through FT-IR, acid−base neutralization titration, ICP, IC, and AAS. By means of verifying the bonding peaks (hydrogen and ionic bonding) under several pHs, molecular bonding between PAEA and ions (Cu2+ and CrO42-) was certified. Surface morphologies of chelating fibers and also after metal ion adsorption were examined by AFM. Compared with a batch test, the adsorption ability was low due to the diffusion path of ions in the dynamic test.
    No preview · Article · Mar 2004 · Industrial & Engineering Chemistry Research
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    Dong Hun Shin · B.S. Hamner · S. Singh · Myung Hwangbo
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    ABSTRACT: This paper presents a motion planning method for mobile manipulators for which the base locomotion is less precise than the manipulator control. In such a case, it is advisable to move the base to discrete poses from which the manipulator can be deployed to cover a prescribed trajectory. The proposed method finds base poses that not only cover the trajectory but also meet constraints on a measure of manipulability. We propose a variant of the conventional manipulability measure that is suited to the trajectory control of the end effector of the mobile manipulator along an arbitrary curve in three space. Results with implementation on a mobile manipulator are discussed.
    Full-text · Conference Paper · Nov 2003
  • Dong Hun Shin · Doo Ho Han
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    ABSTRACT: The twin trowel concrete floor finishing robot consists of a pair of trowels, each of which rotates four plastering blades, and does not have any mechanism like wheels for its locomotion. However, while leveling the concrete floor, it can move in any direction with the unbalanced friction forces occurring between the trowels and the floor, which are controlled by adjusting the posture of the trowels. For the motion control of the robot, this paper discusses the following: First, the typical velocity feedback control method is not dependable because of the difficulties of measuring the robot velocity; secondly, the friction force, which drives the robot, is modeled when the robot is in translation motion; thirdly, the friction force decreases as the robot velocity increases, thus resulting in a saturated velocity dependent on the posture of the trowel; finally, the saturated velocity enables us to control the motion of the robot only by adjusting the posture of trowels without any feedback about the robot velocity.
    No preview · Article · Mar 2003 · Journal of Intelligent and Robotic Systems
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    Dong Hun Shin · Kyung Hoon Park
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    ABSTRACT: Presents the velocity kinematic modeling of wheeled mobile robots (WMRs) by applying the matrix coordinate transformation to every pair of WMRs including wheeled pairs which were dealt with in ad-hoc manners in previous methodologies. A wheeled pair is not replaced with a planar pair and its kinematics is formulated together with those of lower pairs, even though there exists 2 DOF motion at a wheeled pair. The proposed method is implemented successfully to obtain the forward velocity kinematics of a WMR, and it is therefore regarded as a real counterpart to transformation methodologies widely used for kinematics of the robot manipulators.
    Preview · Conference Paper · Feb 2001
  • Dong Hun Shin · Ho Joong Kim
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    ABSTRACT: A self-propulsive polishing robot is proposed as a method that automates a floor polisher and enables the omni-directional motion of a mobile robot without wheels. The proposed robot is composed of twin rotary brushes and does not require any mechanism such as driving wheels for the locomotion of the robot. When the robot polishes a floor with its brushes rotating, the friction forces occur between the brushes and the floor. The friction forces can be controlled by adjusting the posture of the brushes and it enables the robot to move in any desired direction. In this paper, we present a dynamics model of a brush, which corrects the errors of the currently existing model, and propose a new type of polishing robot, which has the twin brushes rotating in the opposite direction to each other. We also present the dynamics of the proposed robot and found the inverse dynamics solution for the omni-directional motion of the robot: we compute the values of the manipulating variables such as tilting directions and tilting amounts of the brushes for the translational, the rotational, and the combined general motion of the robot.
    No preview · Article · Nov 2000 · Journal of Intelligent and Robotic Systems
  • Dong Hun Shin · Doo Ho Han · Ho Joong Kim
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    ABSTRACT: The 2-trowel type concrete floor finishing robot can move in any direction and rotate without any mechanism such as wheels by adjusting the posture of trowels. It utilizes the unbalanced friction forces occurring between the rotary trowels and the floor. Since the quality of the smoothed and polished concrete floor is determined by plastering speed, we need to control the velocity of the robot. However, we cannot use the typical velocity control method because it is very difficult to measure the velocity of the robot, in contrast to the mobile robots with wheels. To overcome this difficulty, the following are studied in the paper. We found that the robot dynamics has disturbance depending on its velocity, and showed that there exists the saturated velocity of the robot which is set by the posture of the trowels, and obtained the relationship between the saturated velocity and the posture in the translation and the rotation. These enable us to control the velocity of the robot only by adjusting the posture of trowels. We built the trowelling robot and are experimenting its performance with the proposed velocity control method
    No preview · Conference Paper · Feb 1999
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    ABSTRACT: To define the role of the Cys residues in the ATP-dependent HslVU protease, mutagenesis was performed to replace either Cys261 or Cys287 in HslU with Val and Cys159 in HslV with Ser or Ala. Whereas HslU/C261V could hydrolyze ATP and support the ATP-dependent proteolytic activity of HslV as well as the wild-type HslU, HslU/C287V could not hydrolyze ATP. Nevertheless, HslU/C287V could support the HslV-mediated proteolysis by forming the HslVU complex in the presence of ATP but not its absence, indicating that ATP binding but not its hydrolysis is essential for proteolysis. Whereas treatment of N-ethylmaleimide (NEM) resulted in dissociation of the oligomeric HslU into monomers, the C261V mutation, but not C287V, prevented the NEM effect. These results suggest that Cys261 is involved in oligomerization and that Cys287 is related to the ATPase function of HslU. NEM also dissociated the dodecameric HslV into monomers, and this effect could be prevented by either the C159S or C159A mutation, suggesting the involvement of Cys159 in oligomerization of HslV. Moreover, either mutation abolished both the basal and HslU-activated proteolytic activity of HslV and its ability to activate the HslU ATPase and to form the HslVU complex, indicating that Cys159 is essential for the proteolytic activity of HslV and its interaction with HslU. These results suggest that the Cys residues play an important role in maintaining the structure and function of the HslVU protease.
    Preview · Article · Sep 1998 · Journal of Biological Chemistry
  • Dong Hun Shin · Ho Joong Klm · Ho Gil Lee · Hong Seok Kim
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    ABSTRACT: A omni-directional self-propulsive trowelling robot is proposed. The proposed robot with two rotary trowels does not require any mechanism such as wheels to obtain driving forces. When the robot flattens a concrete floor with its two rotating trowels, the unbalanced friction forces occur between the trowels and the concrete floor. These friction forces are used to move the robot. Thus, the robot can move in any direction by controlling the two rotary trowels properly. In this paper, firstly the driving force for each trowel is computed by deriving the friction force between the trowel and the concrete floor. Secondly, the relationship between the driving force for the robot and the control variable of the robot is derived. Finally, the basic motions of the robot are realized by using the obtained relationship. This paper figures out how the concrete floor finishing robot with two trowels moves and will contribute to realizing it
    No preview · Conference Paper · Jun 1998
  • Dong Hun Shin · Ho Joong Kim · Ho Gil Lee · Hong-Seok Kim

    No preview · Conference Paper · Jan 1998
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    ABSTRACT: HslVU in Escherichia coli a new two-component ATP-dependent protease composed of two heat-shock proteins, the HslU ATPase and the HslV peptidase which is related to proteasome β-type subunits. Here we show that the reconstituted HslVU enzyme degrades not only certain hydrophobic peptides but also various polypeptides, including insulin B-chain, casein, and carboxymethylated lactalbumin. Maximal proteolytic activity was obtained with a 1:2 molar ratio of HslV (a 250-kDa complex) to HslU (a 450-kDa complex). By itself, HslV could slowly hydrolyze these polypeptides, but its activity was stimulated 20-fold by HslU in the presence of ATP. The ATPase activity of HslU was stimulated up to 50% by the protein substrates, but not by nonhydrolyzed proteins, and this stimulation further increased 2–3-fold in the presence of HslV. Concentrations of insulin B-chain that maximally stimulated the ATPase allowed maximal rates of the B-chain hydrolysis. Furthermore, addition of increasing amounts of ADP or N-ethylmaleimide reduced ATP and protein or peptide hydrolysis in parallel. Thus, HslVU is a protein-activated ATPase as well as an ATP-dependent proteinase, and these processes appear linked. Surprisingly, the protein and peptide substrates do not compete with each other for hydrolysis. Lactacystin strongly inhibits protein degradation, but has little effect on peptide hydrolysis, while the peptide aldehydes are potent inhibitors of hydrolysis of small peptides, but have little effect on proteins. Thus, the functional requirements for ATP-dependent hydrolysis of peptides and proteins appear different.
    Full-text · Article · Sep 1997 · European Journal of Biochemistry
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    ABSTRACT: HslU is the ATPase component of the ATP-dependent HslVU protease in Escherichia coli. To gain an insight into the structure and function of HslU, site-directed mutagenesis was performed to generate a mutation in the ATP-binding site of the ATPase (i.e., to replace the Lys63 with Thr). Unlike the wild-type HslU, the mutant form (referred to as HslU/K63T) could not hydrolyze ATP or support the ATP-dependent hydrolysis of N-carbobenzoxy-Gly-Gly-Leu-7-amido-4-methyl coumarin by HslV. The wild-type HslU (a mixture of monomer and dimer) formed a multimer containing 6-8 subunits in the presence of either ATP or ADP, indicating that ATP-binding, but not its hydrolysis, is required for oligomerization of HslU. However, HslU/K63T remained as a monomer whether or not the adenine nucleotides were present. Furthermore, ATP or ADP could protect HslU, but not HslU/K63T, from degradation by trypsin. These results suggest that the mutation in the ATP-binding site results in prevention of the binding of the adenine nucleotides to HslU and hence in impairment of both oligomerization and ATPase function of HslU.
    Preview · Article · Jan 1997 · FEBS Letters

Publication Stats

283 Citations
41.14 Total Impact Points

Institutions

  • 2007
    • Hallym University Medical Center
      • Department of Laboratory Medicine
      Sŏul, Seoul, South Korea
  • 1998-2006
    • University of Seoul
      • Department of Mechanical and Information Engineering
      Sŏul, Seoul, South Korea
  • 2004-2005
    • Korea Institute of Science and Technology
      • Center for Urban Energy System Research
      Sŏul, Seoul, South Korea
    • Korea University
      • Department of Chemical and Biological Engineering
      Sŏul, Seoul, South Korea
  • 1997-1998
    • Seoul National University
      • College of Natural Sciences
      Seoul, Seoul, South Korea