Eun-Tae Kang

Porous Materials from Waste Bottle Glasses by Hydrothermal Treatment

Porous materials were manufactured by hydrothermal treatment of waste bottle glass without foam agent. Factorial design was applied to analyze data by statistical methods and deal with the important factors for a process. The largest effect for porosity was for temperature of hydrothermal treatment. Amount of water and temperature-water interaction appeared to have little effect. The particle size of raw material was also identified as a major factor by one-way ANOVA and the porosity decreased as the size increased. The sintering temperature was not statistically significant for the porosity but was significant for the pore size. The porous material had compressive strength and thermal conductivity comparing with those of ALC (autoclaved lightweight concrete), although it has higher porosity than for ALC.

Influence of epidermal growth factor supplementation during in vitro maturation on nuclear status and gene expression of canine oocytes.

This study evaluated the effect of epidermal growth factor (EGF) supplementation during in vitro maturation on the meiotic status and the expression of EGF receptor (EGFr), luteinizing hormone receptor (LHr) and gap junction protein α 5 (GJA5) in canine cumulus-oocyte-complexes (COCs). COCs of ≥110 μm diameter, exhibiting dark pigmentation and completely surrounded by three or more layers of cumulus cells collected from anestrus stage ovaries in natural cycle were matured in TCM-199 supplemented with 10% fetal bovine serum, 0.57 mM cysteine, 10 μg/ml LH and FSH, and different concentrations of EGF (0, 10 and 30 ng/ml). Oocytes cultured for 72 h were fixed to assess the nuclear maturation. Expression of EGFr, LHr and GAJ5 was assessed by immunocytochemistry and real-time PCR. Proportion of metaphase II status of oocytes cultured in in vitro maturation (IVM) medium supplemented with 10 ng/ml EGF for 72 h was significantly (P<0.05) higher than 0 and 30 ng/ml EGF supplemented IVM medium (9.8% vs. 6.5% and 5.2%). In both cumulus cells and oocytes, EGFr protein was undetectable, LHr protein level of expression was low and a strong expression of GJA5 protein was observed. The relative abundance (RA) of EGFr transcript revealed low levels and the LHr expression decreased steadily with addition of EGF. However it did not vary among different concentrations of EGF supplementation. The RA of GJA5 transcript exhibited lower level at 10 ng/ml EGF supplementation. In conclusion, the supplementation of 10 ng/ml EGF in IVM media exerted a positive influence on the progression of maturation to MII phase and the expression level of GJA5 at 72 h, but did not demonstrate any stimulatory role on the expression of EGFr and LHr during the maturation of the canine IVM oocytes.

Sintered body characteristics of LAS by addition of CaCO 3 and ZrO 2 using a solid-state reaction

LAS () ceramics were sintered by a solid-state reaction. and were added to the -spodumene () composition of the LAS system for enhancement of sintering behavior and mechanical strength, respectively. We have investigated the sintering characteristics, microstructures, mechanical properties and thermal expansion characteristics according to the change of the amount of additive and sintering temperature of the -spodumene. At 0.1 mol% , the densification of -spodumene was significantly improved. At 0.04 mol% , the strength of -spodumene was also improved. For all the selected all compositions, the thermal expansion coefficient was measured by a dilatometer, which revealed 1.2 to .

Composition-Some Properties Relationships of Non-Alkali Multi-component La 2 O 3 -Al 2 O 3 -SiO 2 Glasses

Non-Alkali multicomponent La2O3-Al2O3-SiO2 glasses has been designed and analyzed on the basis of a mixture design experiment with constraints. Fitted models for thermal expansion coefficient, glass transition temperature, Young’s modulus, Shear modulus and density are as follows: α(/ o C) = 8.41 × 10 �8 x1 +5 .72× 10 �7 x2 +2 .13× 10 �7 x3 +1 .09× 10 �7 x4 +1 .10× 10 �7 x5 +1 .15× 10 �7 x6 +2 .72× 10 �8 x7 +2 .41× 10 �7 x8 − 1.08 ×10 �8 x1x2 +4 .28× 10 �8 x3x7−2.02 × 10 �8 x3x8−1.60 × 10 �8 x4x5−2.71 × 10 �9 x4x8−2.19 × 10 �8 x5x6−3.89 ×10 �8 x5x7 Tg( o C) = 7.36x1+15.35x2+20.14x3+8.97x4+13.85x5+4.22x6+28.21x7−1.44x8−0.84x2x3−0.45x2x5−1.64x2x7+0.93x3x8−1.04x5x8−0.48x6x8 E(GPa) = 2.04x1+14.26x2−1.22x3−0.80x4−2.26x5−1.67x6−1.27x7+3.63x8−0.24x1x2−0.07x2x8+0.14x3x6−0.68x3x8+0.29x4x5+1.28x5x8 G(GPa) = 0.35x1 +1 .78x2 +1 .35x3 +1 .87x4 +9 .72x5+ 29.16x6− 0.99x7 +3 .60x8− 0.48x1x6− 0.50x2x5 +0 .08x3x7−0.66x3x8 +0 .94 x 5x8 ρ(g/cm 3 )=0 .09x1 +0 .51x2− 4.94 × 10 �3 x3− 0.03x4 +0 .45x5− 0.07x6− 0.10x7 +0 .07x8− 9.60 × 10 �3 x1x2− 8.20 × 10 �3 x1x5 +2 .17× 10 �3 x3x7−

(40-x)BaOㆍxFe₂O₃ㆍ60P₂O₅ 유리의 Fe 3+ 이온에 관한 전자스핀공명 연구

(40-x)BaOㆍxFe₂O₃ㆍ60P₂O? glasses with 5≤x≤35 mol% were investigated by ESR spectroscopy. Two resonances observed near g=2.0 and g=4.3. The line at g=4.3 disappeared with the increase of the Fe₂O₃ content. The resonance at g?2.0 displayed characteristic signal consisting of superposed extremely broad and narrow components. The broader one indicates the presence of the association of two or more Fe 3+ ions, antiferromagnetically and the narrow one is related to the microclusters involving iron ions. Temperature dependence of the ESR integrated intensity revealed short-range antiferromagnetic character for x≥15 mol%.

혼합물계획법에 의한 Li₂O-ZrO₂-SiO₂ 유리의 이온전도도와 조성의 관계

The ionic conductivity of Li₂O-ZrO₂-SiO₂ glasses has been designed and analyzed on the basis of a mixture design experiment with constraints. Fitted models for the activation energy and the ionic conductivity are as follows: Q(kJ/㏖)=54.8565x₁+144.825x₂+133.846x₃-170.908x₁x₃-334.338x₂x₃ logσ(300K)=-5.00245x₁?1.17876x₂-15.5173x₃+17.4522x₁x₃ The electrical properties are very sensitive to the ratio of Li₂O/SiO₂. The effect of ZrO₂ is less than that of this ratio but ZrO₂ component attributes to the reduction of the activation energy. The optimal composition for best ionic conduction based on these fitted models is 55Li₂Oㆍ10ZrO₂ㆍ35SiO₂. Its activation energy and ionic conductivity at 300 K are 46.98 kJ/㏖ and 1.08×10?? Ω -1 ㆍ㎝ -1 , respectively.

Structural properties of Pd-barium zirconate dense membrane synthesized by dual sputtering method

Barium zirconate exhibits good thermo-chemical stability and proton conduction at high temperatures, but shows poor electron conductivity. Therefore, for high efficiency of hydrogen separation, a very thin and dense Pd-Barium zirconate membrane has to be coated on a porous substrate. A thin and dense Pd-Barium zirconate membrane was successfully synthesized on a porous substrate by means of dual sputtering method. The structural and chemical features of the membranes sputtered at and were investigated by X-ray diffractometry, and it was found that a well-crystallized membrane, Pm-3m space group of , was synthesized. The surface and cross-sectional morphologies of membrane were assessed by SEM (scanning electron microscopy) and TEM(transmission electron microscopy) of the surface and of cross sections. The cross sectional observation of Pd- membrane by dual sputtering shows that the coating is quite dense with columnar structure.

Characteristics of the sintered body of the Al 2 TiO 5 with addition of LAS (β-spodumene) and Fe 2 O 3

Al2TiO5 ceramics were sintered by a solid-state reaction. LAS (β-spodumene) and Fe2O3 were added to the Al2TiO5 composition for enhancement of sintering behavior such as mechanical strength and thermal shock resistance. The sintered body was much densified by addition of LAS and Fe2O3 because LAS formed the liquid-phase and Fe2O3 suppressed the grain growth. We have systematically investigated the sintering characteristics, microstructures, mechanical properties, and thermal shock resistance according to the change of the amount of additive. When the additive of LAS (20 wt%)-Fe2O3 was added to Al2TiO5, it confirmed that superior mechanical properties of the fracture strength of over 120 MPa and the thermal shock resistance of over 1,200 o C were achieved.

292 Multilineage potential of canine mesenchymal stem cells derived from bone marrow

The purpose of this study is to characterize canine mesenchymal stem cells (MSCs) derived from bone marrow (BM) for use in research on the applications of stem cells in canine models of development, physiology, and disease. BM was harvested antemortem by aspiration from the greater tubercle of the humerus of 30 normal beagle dogs. Canine BM-derived MSCs were isolated according to methods developed for other species and were characterized based on their morphology, growth traits, cell-surface antigen profiles, differentiation repertoire, immunocytochemistry results, and neurotrophic factor expression in vitro. The canine MSCs exhibited a fibroblast-like morphology with a polygonal or spindle-shaped appearance and long processes; further, their cell-surface antigen profiles were similar to those of their counterparts in other species such as rodents and humans. The canine MSCs could differentiate into osteocytes and neurons on incubation with appropriate induction media. RT-PCR analysis revealed that these cells expressed NGF, bFGF, SDF-1, and VEGF. This study demonstrated that isolating canine MSCs from BM, stem-cell technology can be applied to a large variety of organ dysfunctions caused by degenerative diseases and injuries in dogs. Furthermore, our results indicated that canine MSCs constitutively secrete endogenous factors that enhance neurogenesis and angiogenesis. Therefore, these cells are potentially useful for treating dogs affected with various neurodegenerative diseases and spinal-cord injuries.

Computer simulation of ionic conductivity in NASICON by using Monte Carlo method

Abstract From two dimension array, the ionic conductivity in Nasicon assessed a Monte Carlo Method. The maximum conductivity on MCM results ranges from 0.7 to 0.8 and this trends agreed with experimental works of ionic conductivity in Nasicon