Energy Spectrum-based Variable-Density Sampling Distribution Optimized for MR Angiography at Compressed Sensing Technique

Kang, C. K.,Son, Y. D.,Kim, H. K. SPRINGER-VERLAG 2016 Applied magnetic resonance Vol.47 No.2

<P>The aim of this study was to determine the optimal k-space sampling distribution at a compressed sensing (CS) technique for imaging small blood vessels. First, we calculated the energy spectrum of the target vessel and then used this spectral information and the incoherence of undersampling artifacts by polynomial probability density with a power of decay (p) to determine the k-space sampling distribution for CS undersampling. The optimal p was calculated based on the energy spectra of different target vessels having different diameters which were described with full widths at half maximums (FWHMs). The optimized p together with its randomly sampled k-space was then applied to the data previously obtained with conventional magnetic resonance angiography (MRA) at 7.0 Tesla (T) MRI. Two acceleration factors of CS, such as x3 and x5 (33 and 20 %), were reconstructed from the conventional MRA data. The lower p was well fitted to the energy spectra of smaller vessels, in that the sampling density distribution of the lower p was closest to these spectra. However, with the higher acceleration (i.e., 20 %), two p values for small FWHMs, such as 0.56 and 0.84 mm, were not distinguishable because the undersampling of the DC point in k-space for the lower p was infeasible. With an acceleration of 33 %, the optimal p was obtained with the smallest vessels, and it most clearly discriminated the smaller vessels on the MRA images, as compared with other values of p. This study optimized the k-space sampling distribution for small vessels at CS technique. The results suggest that the lower p is suitable for the effective visualization of small vessels. Future studies are needed to appropriately adjust the acceleration factor and optimized p concurrently, since too high acceleration could restrict the applicable range of p and make it difficult to clearly depict smaller vessels.</P>

Sorption of aqueous Pb²⁺ ion on synthetic manganese oxides-intercalated with exchangeable cations

Kang, K.C.,Ju, J.H.,Kim, S.S.,Baik, M.H.,Rhee, S.W. Korean Society of Industrial and Engineering Chemi 2011 Journal of industrial and engineering chemistry Vol.17 No.3

This paper describes the preparation, characterization, and application of three different synthetic manganese oxides (K-MO, H-MO, and Mg-MO). K-MO was synthesized by the reduction of potassium permanganate in an aqueous acidic medium. H-MO was prepared by an ion exchange reaction of K-MO with H<SUP>+</SUP>, while Mg-MO was prepared by reaction of H-MO and an aqueous Mg<SUP>2+</SUP> salt solution under reflux. The subsequent solid products were characterized by a chemical composition analysis, XRD, XPS, FT-IR, SEM, and BET measurements. XPS spectra revealed that only tetravalent manganese ions coordinated octahedrally with oxygens. XRD patterns showed that K-MO turned into a layer-structured material while Mg<SUP>2+</SUP> ions were incorporated into the gallery space of the tunnel-structured Mg-MO. Each type of manganese oxide was used in a sorption study of aqueous Pb<SUP>2+</SUP> at 25<SUP>o</SUP>C. The sorption of Pb<SUP>2+</SUP> ions by manganese oxide resulted in increases of the concentrations of pre-intercalated ions (potassium ions, protons, or magnesium ions) and Mn<SUP>2+</SUP> ions. In spite of the smaller surface area and pore volume, K-MO showed greater sorption capacity for Pb<SUP>2+</SUP> ions than that of Mg-MO under the present experimental conditions, thus suggesting that ion exchange is the main mechanism for the sorption of Pb<SUP>2+</SUP> ions on manganese oxides. The results are anticipated to be applicable to the removal of heavy metal ions from wastewater and the prevention of migration of ions in landfill leachates.

Novel dentin phosphoprotein frameshift mutations in dentinogenesis imperfecta type II

Lee, K‐,E,Kang, H‐,Y,Lee, S‐,K,Yoo, S‐,H,Lee, J‐,C,Hwang, Y‐,H,Nam, KH,Kim, J‐,S,Park, J‐,C,Kim, J‐,W Blackwell Publishing Ltd 2011 Clinical genetics Vol.79 No.4

<P>Lee K‐E, Kang H‐Y, Lee S‐K, Yoo S‐H, Lee J‐C, Hwang Y‐H, Nam KH, Kim J‐S, Park J‐C, Kim J‐W. Novel dentin phosphoprotein frameshift mutations in dentinogenesis imperfecta type II.</P><P>The dentin sialophosphoprotein (<I>DSPP</I>) gene encodes the most abundant non‐collagenous protein in tooth dentin and DSPP protein is cleaved into several segments including the highly phosphorylated dentin phosphoprotein (DPP). Mutations in the <I>DSPP</I> gene have been solely related to non‐syndromic form of hereditary dentin defects. We recruited three Korean families with dentinogenesis imperfecta (DGI) type II and sequenced the exons and exon–intron boundaries of the <I>DSPP</I> gene based on the candidate gene approach. Direct sequencing of PCR products and allele‐specific cloning of the highly repetitive exon 5 revealed novel single base pair (bp) deletional mutations (c.2688delT and c.3560delG) introducing hydrophobic amino acids in the hydrophilic repeat domain of the DPP coding region. All affected members of the three families showed exceptionally rapid pulp chambers obliteration, even before tooth eruption. Individuals with the c.3560delG mutation showed only mild, yellowish tooth discoloration, in contrast to the affected individuals from two families with c.2688delT mutation. We believe that these results will help us to understand the molecular pathogenesis of DGI type II as well as the normal process of dentin biomineralization.</P>

Effects of Dietary Fat Sources on Occurrences of Conjugated Linoleic Acid and trans Fatty Acids in Rumen Contents

An, B.K.,Kang, C.W.,Izumi, Y.,Kobayashi, Y.,Tanaka, K. Asian Australasian Association of Animal Productio 2003 Animal Bioscience Vol.16 No.2

The effects of dietary sources of C18:2 n-6 or C18:3 n-3 fatty acids on the occurrence of conjugated linoleic acid (CLA) and time-dependent changes of free fatty acid fractions in rumen contents were investigated. Sheep (n=4) fitted with rumen fistula were used in a 44 Latin square design wxith each 14 d period. Sheep were fed one of four diets consisting of grass hay and concentrates in a ratio of 70:30. Dietary treatments were 100% concentrates (served as the control), and concentrates were replaced by safflower seed at 30% (SFS), safflower meal at 18% - safflower oil at 12% (SFO), and safflower meal at 18%-linseed oil at 12% (LNO). At the end of each experimental period, rumen contents from each sheep were collected before feeding and at 1, 3, 6 and 12 h after feeding. The levels of cis-9, trans-11 CLA in free fatty acid fraction were considerably increased in all treated groups relative to the control, but not significantly. The increase in cis-9, trans-11 CLA was slightly higher in SFS and SFO groups than group fed diet containing linseed oil. The level of cis-9, trans-11 CLA in free fatty acid fraction was reached to the maximum value at 1hr after feeding and, thereafter gradually decreased to near the value before feeding. The generation of trans-11 C18:1 was significantly higher in all treated groups than that of control. The level of trans-11 C18:1 was linearly increased after feeding of experimental diets, reaching the maximum value at 3 h. Feeding of diets containing polyunsaturated fats to sheep resulted in a marked increase in the levels of trans-11 C18:1 and a slight increase of CLA in free fatty acid fraction of rumen contents. Our results support that endogenous synthesis of CLA from trans-11 C18:1 may be involved the primary source of CLA in dairy product. (Asian-Aust.

Novel effects of FTY720 on perinuclear reorganization of keratin network induced by sphingosylphosphorylcholine: Involvement of protein phosphatase 2A and G-protein-coupled receptor-12

Park, M.K.,Park, S.,Kim, H.J.,Kim, E.J.,Kim, S.Y.,Kang, G.J.,Byun, H.J.,Kim, S.H.,Lee, H.,Lee, C.H. North-Holland ; Elsevier Science Ltd 2016 european journal of pharmacology Vol.775 No.-

<P>Sphingosylphosphorylcholine (SPC) evokes perinuclear reorganization of keratin 8 (K8) filaments and regulates the viscoelasticity of metastatic cancer cells leading to enhanced migration. Few studies have addressed the compounds modulating the viscoelasticity of metastatic cancer cells. We studied the effects of sphingosine (SPH), sphingosine 1-phosphate (S1P), FTY720 and FTY720-phosphate (FTY720P) on SPC-induced K8 phosphorylation and reorganization using Western blot and confocal microscopy, and also evaluated the elasticity of PANC-1 cells by atomic force microscopy. FTY720, FTY720P, SPH, and SIP concentration-dependently inhibited SPC-evoked phosphorylation and reorganization of K8, and migration of PANC-1 cells. SPC triggered reduction and narrow distribution of elastic constant K and conversely, FTY720 blocked them. A common upstream regulator of JNK and ERK, protein phosphatase 2A (PP2A) expression was reduced by SPC, but was restored by FTY720 and FTY72P. Butyryl forskolin, a PP2A activator, suppressed SPC-induced K8 phosphorylation and okadaic acid, a PP2A inhibitor, induced K8 phosphorylation. Gene silencing of PP2A also led to K8 phosphorylation, reorganization and migration. We also investigated the involvement of GPR12, a high-affinity SPC receptor, in SPC-evoked keratin phosphorylation and reorganization. GPR12 siRNA suppressed the SPC-triggered phosphorylation and reorganization of K8. GPR12 overexpression stimulated keratin phosphorylation and reorganization even without SPC. FTY720 and FTY720P suppressed the GPR12-induced phosphorylation and reorganization of K8. The collective data indicates that FTY720 and FTY720P suppress SPC-induced phosphorylation and reorganization of K8 in PANC-1 cells by restoring the expression of PP2A via GPR12. These findings might be helpful in the development of compounds that modulate the viscoelasticity of metastatic cancer cells and various SPC actions. (C) 2016 Elsevier B.V. All rights reserved.</P>

SIGN-R1, a C-type lectin, enhances apoptotic cell clearance through the complement deposition pathway by interacting with C1q in the spleen

MG Prabagar,Y Do,S Ryu,J-Y Park,H-J Choi,W-S Choi,TJ Yun,J Moon,I-S Choi,K Ko,K Ko,C Young Shin,C Cheong,Y-S Kang 한국당과학회 2013 한국당과학회 학술대회 Vol.2013 No.1

Complements, such as C1q and C3, and macrophages in the splenic marginal zone (MZMs) play pivotal roles in the efficient uptake and processing of circulating apoptotic cells. SIGN-R1, a C-type lectin that is highly expressed in a subpopulation of MZMs, regulates the complement fixation pathway by interacting with C1q, to fight blood-borne Streptococcus pneumoniae. Therefore, we examined whether the SIGN-R1-mediated classical complement pathway plays a role in apoptotic cell clearance and immune tolerance. SIGN-R1 first-bound apoptotic cells and this binding was significantly enhanced in the presence of C1q. SIGN-R1-C1q complex then immediately mediated C3 deposition on circulating apoptotic cells in the MZ, leading to the efficient clearance of them. SIGN-R1-mediated C3 deposition was completely abolished in the spleen of SIGN-R1 knockout (KO) mice. Given that SIGN-R1 is not expressed in the liver, we were struck by the finding that C3-deposited apoptotic cells were still found in the liver of wild-type mice, and dramatically reduced in the SIGN-R1 KO liver. In particular, SIGN-R1 deficiency caused delayed clearance of apoptotic cells and aberrant secretion of cytokines, such as TNF-α, IL-6, and TGF-β in the spleen as well as in the liver. In addition, anti-double- and single-stranded DNA antibody level was significantly increased in SIGN-R1-depleted mice compared with control mice. These findings suggest a novel mechanism of apoptotic cell clearance which is initiated by SIGN-R1 in the MZ and identify an integrated role of SIGN-R1 in the systemic clearance of apoptotic cells, linking the recognition of apoptotic cells, the opsonization of complements, and the induction of immune tolerance.

SIGN-R1, a C-type lectin, enhances apoptotic cell clearance through the complement deposition pathway by interacting with C1q in the spleen

Prabagar, M G,Do, Y,Ryu, S,Park, J-Y,Choi, H-J,Choi, W-S,Yun, T J,Moon, J,Choi, I-S,Ko, K,Ko, K,Young Shin, C,Cheong, C,Kang, Y-S Macmillan Publishers Limited 2013 Cell death and differentiation Vol.20 No.4

Complements, such as C1q and C3, and macrophages in the splenic marginal zone (MZMs) play pivotal roles in the efficient uptake and processing of circulating apoptotic cells. SIGN-R1, a C-type lectin that is highly expressed in a subpopulation of MZMs, regulates the complement fixation pathway by interacting with C1q, to fight blood-borne Streptococcus pneumoniae. Therefore, we examined whether the SIGN-R1-mediated classical complement pathway plays a role in apoptotic cell clearance and immune tolerance. SIGN-R1 first-bound apoptotic cells and this binding was significantly enhanced in the presence of C1q. SIGN-R1–C1q complex then immediately mediated C3 deposition on circulating apoptotic cells in the MZ, leading to the efficient clearance of them. SIGN-R1-mediated C3 deposition was completely abolished in the spleen of SIGN-R1 knockout (KO) mice. Given that SIGN-R1 is not expressed in the liver, we were struck by the finding that C3-deposited apoptotic cells were still found in the liver of wild-type mice, and dramatically reduced in the SIGN-R1 KO liver. In particular, SIGN-R1 deficiency caused delayed clearance of apoptotic cells and aberrant secretion of cytokines, such as TNF-α, IL-6, and TGF-β in the spleen as well as in the liver. In addition, anti-double- and single-stranded DNA antibody level was significantly increased in SIGN-R1-depleted mice compared with control mice. These findings suggest a novel mechanism of apoptotic cell clearance which is initiated by SIGN-R1 in the MZ and identify an integrated role of SIGN-R1 in the systemic clearance of apoptotic cells, linking the recognition of apoptotic cells, the opsonization of complements, and the induction of immune tolerance.

한국인 Long Term Non Progressors로부터 분리된 HIV-1 env 및 nef 유전자와 이들의 면역 유전학적 특성 분석에 의한 질병진전 요인 규명

이주실,강춘,김성순,박근용,고운영,기미경,최병선,남정구,서순덕,이성래,구본기,박혜경,도경미,김태규,최희백,조현일,김요숙,김지영,이해정,안수진 국립보건연구원 1999 국립보건원보 Vol.36 No.-

Carbon-coated boron using low-cost naphthalene for substantial enhancement of J_c in MgB₂ superconductor

Ranot, Mahipal,Shinde, K.P.,Oh, Y.S.,Kang, S.H.,Jang, S.H.,Hwang, D.Y.,Chung, K.C. The Korea Institute of Applied Superconductivity a 2017 한국초전도저온공학회논문지 Vol.19 No.3

Carbon coating approach is used to prepare carbon-doped $MgB_2$ bulk samples using low-cost naphthalene ($C_{10}H_8$) as a carbon source. The coating of carbon (C) on boron (B) powders was achieved by direct pyrolysis of naphthalene at $120^{\circ}C$ and then the C-coated B powders were mixed well with appropriate amount of Mg by solid state reaction method. X-ray diffraction analysis revealed that there is a noticeable shift in (100) and (110) Bragg reflections towards higher angles, while no shift was observed in (002) reflections for $MgB_2$ doped with carbon. As compared to un-doped $MgB_2$, a systematic enhancement in $J_c(H)$ properties with increasing carbon doping level was observed for naphthalene-derived C-doped $MgB_2$ samples. The substantial enhancement in $J_c$ is most likely due to the incorporation of C into $MgB_2$ lattice and the reduction in crystallite size, as evidenced by the increase in the FWHM values for doped samples.

한국산 겨우살이 렉틴(KML-C)에 대한 단일크론항체의 생산과 특징

윤택준(T. J. Yoon),유영춘(Y. C. Yoo),강태봉(T. B. Kang),김성훈(S-H Kim),김갑수(K. S. Kim),김종배(J. B. Kim) 대한약학회 2001 약학회지 Vol.45 No.2

We have reported that water-extracted Korean mistletoe(KM-110) had various biological activities such as antitumor and immunomodulatory activity and the lectin fraction(KML-C) of the extract was one of the major factors related to its biological functions. In this paper, we produced murine monoclonal antibody(mAb) against KML-C. The mAbs obtained were largely classified into two groups according to specificity to KML-C and ML-I, a lectin from European mistletoe. One group mABs(9H7-D10 and 3C2-1H4) strongly reacted with KML-C, but not ML-I. In contrast, another group mAbs(8B11-2C5, 8E12-3E9 and 5E10-F1) reacted with both KML-C and ML-1. The subisotypes of these mAbs were shown to be IgG1(9H7-1D10, 3C2-1H4 and 8B11-2C5) or IgM(8E12-3E9 and 5E10-F1). To develop an assay system for determination of the amonunt of KML-C, we established the sandwich ELISA(enzyme-linked immunosorbent assay) method using these mAbs and horse radish peroxidase(HRP) labelled mAbs.In various combinations of the mAbs for coated antibody and detection antibody, the sandwich ELISA quantitatively detected KML-C,showing the detection limit ranging from 7-5,000ng/ml. Especially, reproducibility(C.V.) of the sandwich ELISA, in which 8E12-3E9 was used for coating antibody and 8B11-2C5-HRP for detection antibody, was 4.59-5.83 in intra assay, and 3.9-9.4 in inter assay.