Performance Impact of Resource Conflicts on Chip Multi-processor Servers

Lee, M.,Ryu, Y.,Hong, S.,Lee, C. SPRINGER-VERLAG 2007 ICHIT 2012 Vol.4699 No.-

Adipose-derived stem cell exosomes alleviate pathology of amyotrophic lateral sclerosis in vitro

Lee, M.,Ban, J.J.,Kim, K.Y.,Jeon, G.S.,Im, W.,Sung, J.J.,Kim, M. Academic Press 2016 Biochemical and biophysical research communication Vol.479 No.3

Amyotrophic lateral sclerosis (ALS) is a degenerative disorder that involves the death of motor neurons in the cortex, brain stem, and spinal cord. Adipose-derived stem cells (ADSCs) are considered as a perspective remedy for therapy of neurodegenerative diseases including ALS. Stem cells secrete various factors which can modulate a hostile environment, called paracrine effect. Exosomes are small extracellular vesicles containing cell derived factors and mediate paracrine effect of cells. Thus, exosomes from ADSCs (ADSC-exo) can be a potential candidate of therapeutic effects of stem cells. To investigate the effect of ADSC-exo on the cellular phenotypes of ALS, we used neuronal stem cells (NSCs), which can be differentiated into neuronal cells, isolated from wild type or G93A ALS mice model. ADSC-exo was treated to neuronal cells from G93A ALS mice model. Immunocytochemistry and dot-blot assay result showed that ADSC-exo alleviated aggregation of superoxide dismutase 1 (SOD1). Reduction of cytosolic SOD1 level by ADSC-exo was also confirmed by western blot. Mitochondria display various abnormalities in ALS and the decrease of phospho-CREB and PGC-1α were observed in the G93A cells. ADSC-exo treatment showed normalization of phospho-CREB/CREB ratio and PGC-1α expression level. Our results suggest that ADSC-exo modulates cellular phenotypes of ALS including SOD-1 aggregation and mitochondrial dysfunction, and can be a therapeutic candidate for ALS.

The barycenter property for robust and generic diffeomorphisms

Springer Business + Business Media 2016 Acta mathematica Sinica. English series Vol.32 No.8

<P>Let f: M (d) -> M (d) (d a parts per thousand yen 2) be a diffeomorphism on a compact C (a) manifold on M. If a diffeomorphism f belongs to the C (1)-interior of the set of all diffeomorphisms having the barycenter property, then f is Omega-stable. Moreover, if a generic diffeomorphism f has the barycenter property, then f is Omega-stable. We also apply our results to volume preserving diffeomorphisms.</P>

Predictive value of circulating tumor cells (CTCs) captured by microfluidic device in patients with epithelial ovarian cancer

Lee, M.,Kim, E.J.,Cho, Y.,Kim, S.,Chung, H.H.,Park, N.H.,Song, Y.S. Academic Press 2017 Gynecologic oncology Vol.145 No.2

<P>Conclusion. Proof-of-concept was provided for an electrically conductive and nanoroughened microfluidic platform-based chip designed to capture CTCs in patients with EOC. A larger patient sampling and longer duration of follow-up are needed to determine its suitability for clinical use. (C) 2017 The Authors. Published by Elsevier Inc.</P>

General Expansiveness for Diffeomorphisms from the Robust and Generic Properties

Springer Science + Business Media 2016 Journal of dynamical and control systems Vol.22 No.3

<P>Let f:M -> M be a diffeomorphism on a closed smooth d(d a parts per thousand yen 2)-dimensional manifold. For each , if f belongs to C (1)-interior of the set of the n-expansive diffeomorphisms, then f satisfies quasi-Anosov. For C (1)-generic f, if f is n-expansive then f satisfies both Axiom A and the no-cycle condition.</P>

Selective solid-phase extraction of catecholamines by the chemically modified polymeric adsorbents with crown ether

Lee, M.,Oh, S.Y.,Pathak, T.S.,Paeng, I.R.,Cho, B.Y.,Paeng, K.J. Elsevier 2007 Journal of chromatography Vol.1160 No.1-2

A simple and selective one-step solid-phase extraction procedure using chemically modified polymer resin (Amberlite XAD-4) with crown ether was investigated for the measurement of urinary catecholamines. After loading the urine samples (adjusted to pH 4) on the synthesized adsorbent cartridge, the column was washed with methanol followed by water and then the adsorbed catecholamines were eluted by 1.0mL of 6.0M acetic acid. The effectiveness of sample clean-up method was demonstrated by reversed-phase ion-pair high-performance liquid chromatography with electrochemical detection. Under optimal condition, the recoveries of epinephrine, norepinephrine, and dopamine from spiked urine sample were >86% for all catecholamines. The detection limits (n=5) for epinephrine, norepinephrine, and dopamine were 37, 52, and 46nmol/L, respectively.

Long-term, feeder-free maintenance of human embryonic stem cells by mussel-inspired adhesive heparin and collagen type I

Lee, M.,Kim, Y.,Ryu, J.H.,Kim, K.,Han, Y.M.,Lee, H. Elsevier BV 2016 ACTA BIOMATERIALIA Vol.32 No.-

For practical applications of human embryonic stem cells (hESCs) in regenerative medicine, hESCs should be cultured on a large scale, and at the same time their properties have to be maintained in a controllable manner. Here, we report a chemically defined, scalable culture platform involving co-immobilization of heparin-catechol (HepC) and collagen type-1 (Col) for the long-term maintenance (>18 passages) of hESCs in a feeder-free condition. This platform utilizes a wet-adhesive, mussel-inspired heparin-catechol conjugate as a key component. We hypothesized that the heparin's affinity toward a wide range of proteins, might support undifferentiated in vitro growth of hESC. In fact, on the HepC-coated substrate, most hESC clumps were adhered (~78% at passage 2 (P2)) and expressed pluripotency markers (Fig. 2). Although HepC alone wasn't able to support long-term maintenance of hESCs in a feeder-free system due to decrease in the adhesion rate of hESCs on HepC coating (~ 44% at P4) during the repeated passaging processes, we found that when collagen type I was co-immobilized in the process of HepC coating, the long-term maintenance (passage 18 or more) of hESCs could be achieved with 100% adhesion efficiency (Fig. 4). One remarkable observation is that hESCs on collagen type-I underwent spontaneous differentiation after P6 (Fig. 3), which implied co-immobilized HepC played a role to suppress differentiation of hESCs. This study suggests that unlike the previous studies using proteins, peptides, or synthetic polymers, a polysaccharide, heparin, can be used as a cost-effective component for chemically defined, feeder-free culture of hESC. Statement of Significance: Towards practical applications of human embryonic stem cells (hESCs) in regenerative medicine, hESCs should be cultured on a large scale, and their pluripotent property has to be maintained in a controllable manner. To address these issues, studies that develop chemically defined culture substrates have been explored to replace the widely used, complex, and undefined culture materials represented by Matrigel. Most reports have focused on utilizing proteins, peptides and/or synthetic polymers. However, there have not yet been studies on using polysaccharides as two-dimensional coating materials to potentially replace Matrigel coating. Here, we report that heparin is an effective polysaccharide for the feeder-free, two dimensional culture of hESCs. Our study implies that use of polysaccharides or a polysaccharide/ECM combination can be a new, alternative design principle for hESC culture systems.

Support Vector Machine for String Vectors

Lee, M.,Jo, T. Springer 2006 Lecture Notes in Control and Information Sciences Vol.344 No.-

Anatase TiO₂ nanosheets with surface acid sites for Friedel-Crafts alkylation

Lee, M.,Seo, Y.,Shin, H.S.,Jo, C.,Ryoo, R. Elsevier 2016 Microporous and mesoporous materials Vol.222 No.-

<P>The solvothermal synthesis route to mesoporous TiO2 using a vinylphenol polymer structure-directing agent (SDA) was optimized to provide a high yield of bilayer nanosheets. The resultant TiO2 material exhibited a high BET area of 420 m(2) g(-1) after the removal of SDA. Structural analysis of the nanosheets was carried out using powder X-ray diffraction, high resolution-transmission electron microscopy, Raman spectroscopy and solid-state NMR. The results indicated that the TiO2 material consisted mainly of the bilayer nanosheets with (010) facet-dominant anatase crystal structure. The thickness of the nanosheet was 0.75 nm, corresponding to two unit-cell parameters along the b-axis in the anatase crystal system. More than 10% of the surface Ti atoms were terminated with bridging O-H groups and coordinatively unsaturated Ti atoms, which acted as Bronsted and Lewis acid sites. Accordingly, the anatase nanosheets exhibited catalytic performance in the liquid-phase Friedel Crafts alkylation of aromatic compounds. (C) 2015 Elsevier Inc. All rights reserved.</P>

Vapor-phase hydrogenolysis of glycerol to 1,2-propanediol using a chromium-free Ni-Cu-SiO₂ nanocomposite catalyst

Lee, M.,Hwang, Y.K.,Chang, J.S.,Chae, H.J.,Hwang, D.W. Elsevier 2016 CATALYSIS COMMUNICATIONS - Vol.84 No.-

A Ni-Cu-SiO<SUB>2</SUB> nanocomposite was studied as a catalyst for vapor-phase glycerol hydrogenation to produce 1,2-propanediol (1,2-PDO). Substitution of a small amount (3wt%) of Ni for Cu is beneficial for decreasing the Cu particle size, which would be advantageous for attaining higher 1,2-PDO selectivity and higher glycerol conversion. 92% 1,2-PDO selectivity and 100% glycerol conversion were obtained at 220<SUP>o</SUP>C, 30bar, and a weight hourly space velocity of 0.5h<SUP>-1</SUP> over Ni(3)-Cu(77)-SiO<SUB>2,</SUB> which were nearly identical to those obtained with the conventional copper chromite (CuO-Cr<SUB>2</SUB>O<SUB>3</SUB>) catalyst. Therefore, the present Ni(3)-Cu(77)-SiO<SUB>2</SUB> nanocomposite is regarded as a green and efficient catalyst for glycerol conversion into more valuable 1,2-PDO.