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.

Ganglioside GD1a is specifically formed by the addition of sialic acid to ganglioside GM1a by ST3 β- galactoside α -2,3-sialyltransferase 2 (ST3GAL2). Above all, GD1a are known to be related with the functional regulation of several growth factor receptors, including activation and dimerization of epidermal growth factor receptor (EGFR) in tumor cells. The activity of EGF and EGFR is known to be a very important factor for meiotic and cytoplasmic maturation during in vitro maturation (IVM) of mammalian oocytes. However, the role of gangliosides GD1a for EGFR-related signaling pathways in porcine oocyte is not yet clearly understood. Here, we investigated that the effect of ST3GAL2 as synthesizing enzyme GD1a for EGFR activation and phosphorylation during meiotic maturation. To investigate the expression of ST3GAL2 according to the EGF treatment (0, 10 and 50 ng/ml), we observed the patterns of ST3GAL2 genes expression by immunofluorescence staining in denuded oocyte (DO) and cumulus cell-oocyte-complex (COC) during IVM process (22 and 44 h), respectively. Expression levels of ST3GAL2 significantly decreased (p<0.01) in an EGF concentration (10 and 50 ng/ml) dependent manner. And fluorescence expression of ST3GAL2 increased (p<0.01) in the matured COCs for 44 h. Under high EGF concentration (50 ng/ml), ST3GAL2 protein levels was decreased (p<0.01), and their shown opposite expression pattern of phosphorylation-EGFR in COCs of 44 h. Phosphorylation of EGFR significantly increased (p<0.01) in matured COCs treated with GD1a for 44 h. In addition, ST3GAL2 protein levels significantly decreased (p<0.01) in GD1a (10 μM) treated COCs without reference to EGF pre-treatment. These results suggest that treatment of exogenous ganglioside GD1a may play an important role such as EGF in EGFR-related activation and phosphorylation in porcine oocyte maturation of in vitro.

Large single grain Gd1.5Ba2Cu3O7-y (Gd1.5) bulk superconductors were fabricated by a top-seeded melt growth (TSMG) process using an NdBa2Cu3O7-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 (Tc) of the top surface of the single grain Gd1.5 sample was as high as 93.5 K. The critical current densities (Jcs) at 77 K and 1T and 1.5 T were in ranges of 25,200-43,900 A/cm2 and 10,000-23,000 A/cm2, 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 Gd2BaCuO5 (Gd211) particles of a few μm in size, which are flux pinning sites of Gd123, were trapped within the GdBa2Cu3O7-y (Gd123) grain; unreacted Ba3Cu5O8 liquid and Gd211 particles were present near the edge regions of the single grain Gd1.5 bulk compact.

Red phosphors of Gd1-xAl3(BO3)4:Eux3+ were synthesized by using the solid-state reaction method. The phasestructure and morphology of the phosphors were measured using X-ray diffraction (XRD) and field emission-scanning electronmicroscopy (FE-SEM), respectively. The optical properties of GdAl3(BO3)4:Eu3+ phosphors with concentrations of Eu3+ ions of0, 0.05, 0.10, 0.15, and 0.20mol were investigated at room temperature. The crystals were hexagonal with a rhombohedrallattice. The excitation spectra of all the phosphors, irrespective of the Eu3+ concentrations, were composed of a broad bandcentered at 265nm and a narrow band having peak at 274nm. As for the emission spectra, the peak wavelength was 613nmunder a 274nm ultraviolet excitation. The intensity ratio of the red emission transition (5D0→7F2) to orange (5D0→7F1) showsthat the Eu3+ ions occupy sites of no inversion symmetry in the host. In conclusion, the optimum doping concentration of Eu3+ions for preparing GdAl3(BO3)4:Eu3+ phosphors was found to be 0.15mol.

Red-orange phosphors Gd1-xPO4:Eux3+ (x=0, 0.05, 0.10, 0.15, 0.20) were synthesized with changing theconcentration of Eu3+ ions using a solid-state reaction method. The crystal structures, surface morphology, and optical propertiesof the ceramic phosphors were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), andphotoluminescence (PL) spectrophotometry. The XRD results were in accordance with JCPDS (32-0386), and the crystalstructures of all the red-orange phosphors were found to be a monoclinic system. The SEM results showed that the size ofgrains increases and then decreases as the concentration of Eu3+ ionincreases. As for the PL properties, all of the ceramicphosphors, irrespective of Eu3+ ion concentration, had orange and red emissions peaks at 594nm and 613nm, respectively. Themaximum excitation and emission spectra were observed at 0.10mol of Eu3+ ion concentration, just like the grain size. Anorange color stronger than the red means that 5D0→7F1 (magnetic dipole transition) is dominant over the 5D0→7F2 (electricdipole transition), and Eu3+ is located at the center of the inversion symmetry. These properties contrasted with those of a redphosphor Y1-xPO4:Eux3+, which has a tetragonal system. Therefore, we confirm that the crystal structure of the host materialhas a major effect on the resulting color.