• Korean Journal of Materials Research
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• v.23 no.6
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• pp.309-315
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• 2013

$GdBa_2Cu_3O_{7-y}$(Gd123) powders were synthesized by the solid-state reaction method using $Gd_2O_3$ (99.9% purity), $BaCO_3$ (99.75%) and CuO (99.9%) powders. The synthesized Gd123 powder and the Gd123 powder with $Gd_2O_3$ addition ($Gd_{1.5}Ba_2Cu_3O_{7-y}$(Gd1.5)) were used as raw powders for the fabrication of Gd123 bulk superconductors. The Gd123 and Gd1.5 bulk superconductors were fabricated by sintering or a top-seeded melt growth (TSMG) process. The superconducting transition temperature ($T_{c,onset}$) of the sintered Gd123 was 93 K and the transition width was as large as 20 K. The $T_{c,onset}$ of the TSMG processed Gd123 was 82 K and the transition width was also as large as 12 K. The critical current density ($J_c$) at 77 K and 0 T of the sintered Gd123 and TSMG processed Gd123 were as low as a few hundreds A/$cm^2$. The addition of 0.25 mole $Gd_2O_3$ and 1 wt.% $CeO_2$ to Gd123 enhanced the $T_c$, $J_c$ and magnetic flux density (H) of the TSMG processed Gd123 sample owing to the formation of the superconducting phase with high flux pinning capability. The $T_c$ of the TSMG processed Gd1.5 was 92 K and the transition width was 1 K. The $J_cs$ at 77 K (0 T and 2 T) were $3.2{\times}10^4\;A/cm^2$ and $2.5{\times}10^4\;A/cm^2$, respectively. The H at 77 K of the TSMG-processed Gd1.5 was 1.96 kG, which is 54% of the applied magnetic field (3.45 kG).

• Progress in Superconductivity and Cryogenics
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• v.14 no.4
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• pp.28-31
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• 2012

We report the solid-liquid phase equilibria on the $GdBa_2Cu_3O_{7-{\delta}}$ (GdBCO) stability phase diagram in low oxygen pressures ($PO_2$) ranging from 1 to 100 mTorr. On the basis of the GdBCO stability phase diagram experimentally determined in low oxygen pressures, the isothermal sections of three different phase fields on log $PO_2$ vs. 1/T diagram were schematically constructed within the $Gd_2O_3-Ba_2CuO_y-Cu_2O$ ternary system, and the solid-liquid phase equilibria in each phase field were described. The invariant points on the phase boundaries include the following three reactions; a pseudobinary peritectic reaction of $GdBCO{\leftrightarrow}Gd_2O_3$ + liquid ($L_1$), a ternary peritectic reaction of $GdBCO{\leftrightarrow}Gd_2O_3+GdBa_6Cu_3O_y$ + liquid ($L_2$), and a monotectic reaction of $L_1{\leftrightarrow}GdBa_6Cu_3O_y+L_2$. A conspicuous feature of the solid-liquid phase equilibria in low $PO_2$ regime (1 - 100 mTorr) is that the GdBCO phase is decomposed into $Gd_2O_3+L_1$ or $Gd_2O_3+GdBa_6Cu_3O_y+L_2$ rather than $Gd_2BaCuO_5+L$ well-known in high $PO_2$ like air.

• IMMUNE NETWORK
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• v.3 no.2
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• pp.118-125
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• 2003

Background: Disialoganglioside GD2 is a tumor-associated antigen that is overexpressed on tumor cells of neuroectodermal origin, such as melanoma and neuroblastoma. Anti-idiotypic antibodies that mimic GD2 may induce more effective immune responses than GD2 antigen itself, because they are protein antigens and are known to be able to break immune tolerance. In this study, to explore the potential of anti-idiotypic antibodies as tumor vaccines, the ability of anti-idiotypic antibodies (Ab2) to induce anti-anti-idiotypic antibodies (Ab3) that bind to the original antigen GD2 was investigated. Methods: Six monoclonal anti-idiotypic antibodies (1A8, 1G5, 2B6, 3A4, 3D6, 3H9) to monoclonal antibody M2058, which is a monoclonal antibody to GD2, were produced in mice. Three (1A8, 3A4, 3H9) of them were selected based on their ability to inhibit the binding of Ab1 to D142.34 (murine melanoma cell expressing GD2). These 3 different Ab2 were injected into rabbits, and rabbit Ab3 induced by each of them were characterized. Results: Ab3-containing sera from two rabbits immunized with 1A8, 3A4, or 3H9 bound significantly (P<0.05) to D142.34 but not to B78.96 (GD2-negative cell), and bound significantly (P<0.05) to isolated GD2 but not to GD1a. Ab3-containing sera from two rabbits immunized with 3A4 or 3H9 inhibited significantly (P<0.05) the binding of Ab1 M2058 to D142.34, and inhibited significantly (P<0.05) the binding of Ab1 M2058 to the Ab2. Conclusion: These results suggest that anti-idiotypic antibodies 3A4 and 3H9 have a potential to be used as vaccines against tumors expressing GD2 by inducing GD2-specific antibodies (Ab3).

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.4
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• pp.347-356
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• 2020

Gangliosides are glycolipids in which oligosaccharide is combined with sialic acids. Our previous studies have suggested an interplay between ganglioside GD1a/GT1b and meiotic maturation capacity in porcine oocyte maturation. Furthermore, ganglioside GD1a and GT1b are known for its antioxidant activity, but it is still unclear whether possible antioxidant role of GD1a and GT1b is involved in porcine embryos development competence during in vitro culture (IVC). Here, the effects of ganglioside GD1a and GT1b on the embryonic developmental competence during in vitro culture of porcine were investigated. The effects of ganglioside GD1a and GT1b on the expression of ST3GAL2 were confirmed during embryos development (2-cell, 4-cell, 8-cell and blastocyst) using immunofluorescent staining (IF). As a result, the fluorescent expression of ST3GAl2 was higher in embryos at 4-8 cells stage than blastocysts. Blastocyst development rate significantly increased in only 0.1 μM GD1a and GT1b treated groups compared with control group. To investigate the cellular apoptosis, we analyzed TUNEL assay. In case of only 0.1 μM GD1a and GT1b treated groups, the total number of cells in blastocyst compared with control group, but there was no significant difference in the rate of apoptotic cells. We identified the intracellular ROS levels using DCF-DA staining. According to the result, ROS production significantly decreased in blastocysts derived from the 0.1 μM GD1a and GT1b treated groups. These results suggest that ganglioside GD1a and GT1b improve the developmental competence of porcine embryos via reduction of intracellular ROS during preimplantation stage.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.119.1-119.1
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• 2017

Fe-(10, 24 wt.%) Gd-B 합금을 진공 주조하고 상분석과 내식성 평가 및 표면 경도를 측정하였다. 주조된 Fe-10 wt.% Gd-B 합금의 상은 주로 $Fe_2Gd$, $Fe_3Gd$, $B_4FeGd$, $GdB_2$이었으며, Fe-24 wt.% Gd-B 합금은 주로 $Fe_2Gd$, $Fe_3Gd$, $Fe_9Gd$, $Fe_{17}Gd_2$, $B_4FeGd$, $GdB_2$이었다. 인공해수 분위기에서의 부식 속도와 부식 전위는 각각 2.771, 2.914 [$mA/cm^2$]과 -623.9, -607.8 [$mV_{SHE}$]이었다. 표면 경도는 각각 220, 208 [Hv] 이었다. Gd 함량이 증가할수록 부식 속도는 증가하였고 표면 경도는 감소하는 경향을 보였다.

• Journal of Nutrition and Health
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• v.55 no.2
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• pp.240-249
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• 2022

Purpose: Glabridin (GD) is a bio-available isoflavane isolated from the root extract of licorice (Glycyrrhiza glabra L.). It exhibits a variety of pharmacological activities such as anti-inflammatory and anti-oxidant activities. However, extracellular vesicles (EVs) secretion and the anti-cancer mechanism of action remains largely unknown. The present study investigates the anticancer effects of GD by determining the inhibition of EVs secretion in the human breast cancer cell line, MDA-MB-231. Methods: Cell viability, reactive oxygen species (ROS) production, migration, invasion rate, and vascular endothelial growth factor (VEGF) concentration were assessed in MDA-MB-231 cells treated with increasing concentrations of GD (0.1, 1, 5, 10, 20 µM). Subsequently, EV secretion and exosomal DEL-1 protein expression were evaluated to determine the anticancer effects of GD. Results: The results showed that GD significantly inhibited the cell proliferation of MDA-MB-231 cells in a dose- or time-dependent manner. Also, ROS production and apoptosis marker protein cleaved caspase-3 were significantly increased in GD-treated MDA-MB-231, compared to control. Furthermore, GD exposure resulted in significantly decreased not only migration and invasion rates but also the VEGF concentration, thereby contributing to a reduction in angiogenesis. Interestingly, the concentration and number of EVs as well as EV marker proteins, such as CD63 and TSG101, were decreased in GD-treated MDA-MB-231 cells. Markedly, extracellular matrix protein DEL-1 as angiogenesis factor was decreased in EVs from GD-treated MDA-MB-231 cells. Conclusion: This study identifies that the anti-cancer molecular mechanism of GD is exerted via inhibition of angiogenesis and EVs secretion, indicating the potential of GD as a chemotherapeutic agent for breast cancer.

• Korean Journal of Materials Research
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• v.22 no.11
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• pp.569-574
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• 2012

Large single grain $Gd_{1.5}Ba_2Cu_3O_{7-y}$ (Gd1.5) bulk superconductors were fabricated by a top-seeded melt growth (TSMG) process using an $NdBa_2Cu_3O_{7-y}$ seed. The seeded Gd1.5 powder compacts with a diameter of 50 mm were subjected to the heating cycles of a TSMG process. After the TSMG process, the diameter of the single grain Gd1.5 compact was reduced to 43 mm owing to the volume contraction during the heat treatment. The superconducting transition temperature ($T_c$) of the top surface of the single grain Gd1.5 sample was as high as 93.5 K. The critical current densities ($J_cs$) at 77 K and 1T and 1.5 T were in ranges of 25,200-43,900 $A/cm^2$ and 10,000-23,000 $A/cm^2$, respectively. The maximum attractive force at 77 K of the sample field-cooled using an Nd-B-Fe permanent magnet (surface magnetic field of 0. 527 T) was 108.3 N; the maximum repulsive force of the zero field-cooled sample was 262 N. The magnetic flux density of the sample field-cooled at 77 K was 0.311T, which is approximately 85% of the applied magnetic field of 0.375 T. Microstructure investigation showed that many $Gd_2BaCuO_5$ (Gd211) particles of a few ${\mu}m$ in size, which are flux pinning sites of Gd123, were trapped within the $GdBa_2Cu_3O_{7-y}$ (Gd123) grain; unreacted $Ba_3Cu_5O_8$ liquid and Gd211 particles were present near the edge regions of the single grain Gd1.5 bulk compact.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1177-1181
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• 2010

The synthesis and characterization of gold nanoparticles coated by Gd-chelate (GdL@Au) is described, where L is a conjugate of DTPA (DTPA = diethylenetriamine-N,N,N',N",N"-pentaacetic acid) and 4-aminothiophenol. These particles are obtained by the replacement of citrate from the gold nanoparticle surfaces with gadolinium chelate (GdL). The average size of GdL@Au is 12 nm with a loading of GdL reaching up to $1.4{\times}10^3$ per particles, and they demonstrate very high r1 relaxivity (${\sim}10^4mM^{-1}s^{-1}$) and the r1 relaxivity per [Gd] is as high as $10mM^{-1}s{-1}$. Here, we also describe the use of bimodality of this contrast agent (CA) as a highly efficient CT contrast agent based on gold nanoparticles (GNPs) that overcome the limitations of iodine based contrast agent. The MTT assay performed on this CAs reveals the cytotoxicity as low as that for Omniscan$^{(R)}$ in the concentration range required to obtain intensity enhancement in the in vivo MRI study.

• Molecular & Cellular Toxicology
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• v.2 no.1
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• pp.21-28
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• 2006

Gadolinium chloride ($GdCl_{3}$) was known to block Kupffer cells and generally its toxicity study based on blocking these cells. Therefore, $GdCl_{3}$ frequently used to study toxic mechanisms of hepatotoxicants inducing injury through Kupffer cells. We also tried to investigate the effect of $GdCl_{3}\;on\;CCl_{4}$ toxicity, typical hepatotoxicants. Administration of $GdCl_{3}$ to mice significantly suppressed AST (asparatate amino transferase), ALT (alanine amino transferase) levels which were increased by $CCl_{4}$ treatment. However, $GdCl_{3}$ didn't inhibit the phagocytotic activity of Kupffer cells. Malondialdehyde (MDA) is a good indicator of the degree of lipid peroxidation. In this study, MDA increased by $GdCl_{3}$ administration not by $CCl_{4}$. To understand the toxicity of $GdCl_{3}$, we analyzed global gene expression profile of mice liver after acute $GdCl_{3}$ injection. Four hundred fifty two genes were differentially expressed with more than 2-fold in at least one time point among 3 hr, 6 hr, and 24 hr. Several genes involved in fibrogenesis regulation. Several types of pro-collagens (Col1a2, Col5a2, Col6a3, and Col13a1) and tissue inhibitor of metal-loproteinase1 (TIMP1) were up regulated during all the time points. Genes related to growth factors, chemokines, and oxidative stress, which were known to control fibrogenesis, were significantly changed. In addition, $GdCl_{3}$ induced abnormal regulation between lipid synthesis and degradation related genes. These data will provide the information about influence of $GdCl_{3}$ to hepatotoxicity.

• Advances in nano research
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• v.1 no.3
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• pp.159-169
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• 2013

A preparation method for gadolinium compound (GdC) nanoparticles coated with silica ($GdC/SiO_2$) is proposed. GdC nanoparticles were prepared with a homogeneous precipitation method at $80^{\circ}C$ using $1.0{\times}10^{-3}$ M $Gd(NO_3)_3$, 0.5 M urea and $0-3.0{\times}10^{-4}$ M ethylenediarinnetetraacetic acid disodium salt dihydrate (ETDA) in water. As a result of preparation at various EDTA concentrations, GdC nanoparticles with a size as small as $40.5{\pm}6.2$ nm, which were colloidally stable, were prepared at an EDTA concentration of $2.0{\times}10^{-4}$ M. Silica-coating of the GdC nanoparticles was performed by a St$\ddot{o}$ber method at $35^{\circ}C$ using $1.0-10.0{\times}10^{-3}$ M tetraethylorthosilicate (TEOS), 11 M $H_2O$ and $1.5{\times}10^{-3}$ M NaOH in ethanol in the presence of $1.0{\times}10^{-3}$ M GdC nanoparticles. Performance of preparation at various TEOS concentrations resulted in production of $GdC/SiO_2$ particles with an average size of $106.1{\pm}11.2$ nm at a TEOS concentration of $5.0{\times}10^{-3}$ M. The gadolinium (Gd) concentration of $1.0{\times}10^{-3}$ M in the as-prepared $GdC/SiO_2$ particle colloid solution was increased up to a Gd concentration of 0.2 M by concentrating with centrifugation. The core-shell structure of $GdC/SiO_2$ particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The concentrated $GdC/SiO_2$ colloid solution showed images of X-ray and magnetic resonance with contrast as high as commercial Gd complex contrast agents.