The influences of various carbonization temperatures on electrical resistivity and morphologies of polyacrylonitrile (PAN)-based nanofiber webs were studied. The diameter size distribution and morphologies of the nanofiber webs were observed by a scanning electron microscope. The electrical resistivity behaviors of the webs were evaluated by a volume resistivity tester. From the results, the volume resistivity of the carbon webs was ranged from 5.1×10-1 Ω·cm to 3.0×10-2 Ω·cm, and the average diameter of the fiber webs was varied in the range of 310 to 160 nm with increasing the carbonization temperature. These results could be explained that the graphitic region of carbon webs was formed after carbonization at high temperatures. And the amorphous structure of polymeric fiber webs was significantly changed to the graphitic crystalline, resulting in shrinking the size of fiber diameters.

Molecular sieving carbon (MSC) for separating O2-N2 and CO2-CH4 has been prepared through chemical vapor deposition (CVD) of methane and benzene on activated carbon spheres (ACS) derived from polystyrene sulfonate beads. The validity of the material for assessment of molecular sieving behavior for O2-N2 and CO2-CH4 pair of gases was assessed by the kinetic adsorption of the corresponding gases at 25℃. It was observed that methane cracking on ACS lead to deposition of carbon mostly in whole length of pores rather than in pore entrance, resulting in a reduction in adsorption capacity. MSC showing good selectivity for CO2-CH4 and O2-N2 separation was obtained through benzene cracking on ACS with benzene entrantment of 0.40×10-4 g/ml at cracking temperature of 725℃ for a period of 90 minutes resulting in a selectivity of 3.31:1.00 for O2-N2 and 8.00:1.00 for CO2-CH4 pair of gases respectively.

The present study investigated the effects of follicle stimulating hormone (FSH) and human chorionic gonadotrophin (hCG) on the nuclear maturation of canine oocytes. Oocytes were recovered from mongrel female ovaries in various reproductive states; follicular, luteal or anestrous stage. Oocytes were cultured in serum-free tissue culture medium (TCM)-199 supplemented with various concentrations of FSH (Exp. 1: 0, 0.5, 1.0 or 10 IU) or hCG (Exp. 2: 0, 0.5, 1.0 or 10 IU) or both (Exp. 3: 1 IU FSH + 1 IU hCG) for 72 hr to determine the effective concentration of these hormones, and to examine their combined effect. After maturation culture, oocytes were denuded in PBS containing 0.1% (w/v) hyaluronidase by gentle pipetting. The denuded oocytes were stained with 1.9 μM. Hoechst 33342 in glycerol and the nuclear state of oocytes was evaluated under UV light. More (p<0.05) oocytes matured to MII stage when follicular stage oocytes were supplemented with 1 IU FSH (6.2%) compared with the control, 0.1 or 10.0 IU FSH (0 to 1.2%). Significantly higher (p<0.05) maturation rate to MII stage was observed in follicular stage oocytes supplemented with 1.0 IU hCG (7.2%) compared with the control or other hCG supplemented groups (0 to 1.5%). However, the combination of FSH and hCG did not improve the nuclear maturation rate of canine oocyte (2.4 %) compared with FSH (6.2%) and hCG alone (7.2%). In conclusion, FSH or hCG alone significantly increased the maturation of canine oocytes to MII stage.

Carbon/TiO2 composites were prepared by CCl4 solvent mixing method with different mixing ratios. Since the carbon layers derived from pitch on the TiO2 particles were porous, the Carbon/TiO2 composite series showed a good adsorptivity and photo decomposition activity. The BET surface area for the carbon layer in the sample increases to increasing with pitch contents. The SEM results present to the characterization of porous texture on the Carbon/TiO2 composite and pitch distributions on the surfaces for all the materials used. From XRD data, a weak and broad carbon peak of graphene with pristine anatase peaks were observed in the X-ray diffraction patterns for the Carbon/TiO2. The EDX spectra show the presence of C, O and S with strong Ti peaks. Most of these samples are richer in carbon and major Ti metal than any other elements. Finally, the excellent photocatalytic activity of Carbon/TiO2 with slope relationship between relative concentration (C/C0) of MB and t could be attributed to the homogeneous coated pitch on the external surface by CCl4 solvent method.

The purpose of this study was to determine effects of oxytocin and interleukin-1α on in vitro development of bovine embryo cultured with endometrial epithelial and stromal cells isolated from bovine uterus. The expressions of COX-2 mRNA in bovine endometrium were also studied. When embryos were cultured with epithelial cells, the rate of blastocysts was significantly (p<0.05) higher in embryos treated with oxytocin than that of control group. The rate of hatched blastocysts was also significantly (p<0.05) higher in embryos treated with oxytocin than those of two control groups. On the other hand, when the embryos were cultured with stromal cells, the rate of blastocysts were significantly (p<0.05) higher than those of groups treated with IL-1α, oxytocin and control with stromal cells than that of control group without stromal cells. The rate of blastocysts hatched were also significantly (p<0.05) higher in group treated with IL-1α than those of control group without stromal cells and oxytocin group. In another experiment, COX-2 gene was expressed in embryo group treated with oxytocin during the co-culture of embryos with epithelial cells. In contrast, COX-2 mRNA was expressed in group treated with IL-1α when the embryos were cultured with stromal cell. This result shows that oxytocin and IL-1α were stimulate embryo development in vitro when embryos were cultured with epithelial and stromal cells, and can affect the development of bovine embryos in the uterus.

In order to generate transgenic goats expressing human growth hormone (hGH) in their mammary glands, goat β-casein/hGH hybrid gene was introduced into goat zygotes by pronuclear microinjection. DNA-injected embryos were transferred to the oviduct of recipients at 2-cell stage or to the uterus at morula/blastocyst stage after cultivation in glutathione-supplemented mSOF medium in vitro. Pregnancy and survival rate were not significantly different between 2-cell embryos and morula/blastocysts transferred to oviduct and uterus, respectively. One transgenic female goat was generated from 153 embryos survived from DNA injection. Southern blot analysis revealed that the transgenic goat harbored single-copy transgene with a partial deletion in its sequences. Despite of the partial sequence deletion, the transgene was successfully expressed hGH at the level of 72.1±15.1 μg/ml in milk throughout lactation period, suggesting that the sequence deletion had occurred in non-essential part of the transgene for the transgene expression. Unfortunately, however, the transgene was not transmitted to her offspring during three successive breeding seasons. These results demonstrated that goat β-casein/hGH gene was integrated into the transgenic goat genome in a mosaic fashion with a partial sequence deletion, which could result in a low level expression of hGH and a failure of transgene transmission.

Transforming growth factor-β (TGF-β) has been shown to have a positive effect on in vitro fertilization (IVF) and has been reported to stimulate meiosis at follicular level in variety of species. The study was designed to determine the expression patterns of TGF-β1, TGF-β receptors type Ⅰ, Ⅱ and Smads gene in bovine oocytes and embryos. TGF-β1 and their receptors were observed in the unfertilized oocytes. TGF-β1 and type Ⅱ receptor were not expressed at the blastocyst stage, however, only type I receptor was exclusively observed at the same stage. The blastocyst stage, in particular, showed high levels of mRNA expression patterns containing a TGF-β type Ⅰ receptor. The mRNA expression pattern of Smad 2 at all stages of embryonic development was similar in all respect with TGF-β1 type I receptor. On the contrary, Smad 3 and 4 were expressed with high and low level mRNA at the blastocyst stage. In conclusion, it is suggested that TGF-β signaling may be regarded as an important entity during the preimplantation embryo development.

The Chinese Hamster Ovarian cells CHOK1 are one of the most extensively used cells for the evaluation of gene expression and toxicology. However, these cells are frequently used for biomedical research without consideration of their cytogenetic characteristics. Therefore, we carried out to investigate the karyologic profiles, the frequency and type of chromosome aberration, and the distribution of telomeric DNA on chromosomes of the CHOK1 cells. The GTGbanding and fluorescence in situ hybridization on CHOK1 cells were performed to characterize the karyotype and the distribution of telomeric DNA. The present study revealed that the chromosome modal number of CHOK1 cells was 2n=20; eight chromosomes appeared to be identical with those of the normal Chinese hamster, whereas the remaining 12 chromosomes were shown to be translocated, deleted, inversed, or rearranged from Chinese hamster chromosomes. The telomeric DNA on CHOK1 chromosomes was intensively distributed at the centromeres rather than the ends of chromosomes. In addition, three chromosomes had interstitial telomeres and one marker chromosome entirely consisted of telomeric DNAs. The frequency and type of chromosome aberrations in CHOK1 cells were examined. Of the 822 metaphase spreads, 68 (8.3%) cells resulted in chromosome aberrations of which the chromosome breakage was the most frequently occurred.

There are replete numbers of reports which have apparently shown that established patterns of methylation are critical for normal mammalian development. Here, we report expression of the DNA methyltransferases (Dnmts) family during mouse early development. Transcription of Dnmt1o occurs in one-cell and morula stage embryos, whereas Dnmt1s transcripts were detectable in all cells and tissues examined during the study. Dnmt3a1 transcript was detected in all cells and Dnmt3a2 transcript was particularly detected in the oocyte and 1-cell stages. Low level Dnmt3b1 transcripts were expressed ubiquitously in oocyte, 1-cell, and preimplantation embryos except 2～4 cell stages. Dnmt3b3 transcripts were only detected in E7.5 embryo and ovary. Furthermore, Dnmt3l transcripts were detectable in all cells and tissues examined. Unlike Dnmt1, both Dnmt3a and Dnmt3b proteins existed in the nucleus of preimplantation embryos till the morula stage. These Results suggest that differences Dnmts expression level exist and genomic DNA methylation patterns may be determined partly through differential expression of Dnmts during early development.

Our previous research has identified granulin (grn) and p130 genes as sex steroidinducible genes in the rat hypothalamus, which might be involved in sexual differentiation of the brain. Phthalate esters that are used as plasticizers and also found at low levels in foods such as dairy products are often mentioned as suspected endocrine disrupters. The purpose of the present study is to elucidate whether perinatal exposure to dinbutyl phthalate (DBP), diisononyl phthalate (DINP) and di2ethylhexyl adipate (DEHA) affects hypothalamic sex steroidinducible genes. The present study assessed the effects of perinatal exposure to DBP, DINP and DEHA on sex steroid hormones levels and hypothalamic grn and p130 mRNA expressions at postnatal day (PND) 3 and 7. Pregnant rats were fed a soyfree diet containing 20, 200, 2,000 and 10,000 ppm of DBP, 40, 400, 4,000 and 20,000 ppm of DINP, or 480, 2,400 and 12,000 ppm of DEHA from gestational day (GD) 15 to GD 3 or 7. At PND 3 and 7, perinatal exposure to these chemicals did not substantially affect serum concentrations of testosterone and estradiol. At PND 3, the expression of grn mRNA levels in males was decreased by DEHA, and that of p130 was decreased by DBP, DINP and DEHA, though the effects were not dosedependent. At PND 7, the expression of grn gene in female pups was increased by higher doses of DBP and all the doses, except for 4,000 ppm, of DINP, while that in male pups decreased by 480 and 12,000 ppm of DEHA. Hypothalamic expression of p130 mRNA in males was increased by lower doses of DBP and all the doses of DINP, whereas that of females was decreased by 480 and 2,400 ppm of DEHA. These results suggest that these chemicals may affect the expression of grn and p130 genes by directly acting on the hypothalamus, thus leading to inappropriate expression of these genes.

Di-n-butyl phthalate (DBP), diisononyl phthalate (DINP) and di-(2-ethylhexyl) adipate (DEHA) are ubiquitously distributed chemicals that are widely used as plasticizers and also found at low levels in foods. The aims of this study were to determine whether perinatal exposure to DBP, DINP and DEHA could alter normal patterns of neonatal development. Dams were provided with pulverized soy-free diet containing 20, 200, 2,000 and 10,000 ppm of DBP, 40, 400, 4,000 and 20,000 ppm of DINP, or 480, 2,400 and 12,000 ppm of DEHA from gestational day 15 to postnatal day 21. Exposure to the high doses of DBP, DINP and DEHA during gestational period significantly decreased food consumption and body weight gain of dams. These chemicals reduced neonatal body weight as well as that of the after maturation. Also, exposure to DINP of all the doses used and the higher doses (2,400 and 12,000 ppm) of DEHA decreased AGD at PND 1 in male neonates, though that to DBP did not affect AGD in males. In female neonates, an increase in AGD was observed in DBP- and DINP-exposed animals at the highest doses. Moreover, these chemicals affected survival rate of pups at PND 5, and delayed onset of eye opening in all chemical-exposed groups at PND 17. These results suggest that perinatal exposure to these chemicals may affect the normal development and / or growth of offspring.

Temperature signaling can be initiated by members of transient receptor potential (thermo-TRP) channels. Hot and cold substances applied to teeth usually elicit pain sensation. Since odontoblasts constitute a well-defined layer between the pulp and the mineralized dentin, being first to encounter thermal stimulation from oral cavity, they may be involved in sensory transduction process, in addition to their primary function as formation of dentin. We investigated whether thermo-TRP channels are expressed in a odontoblast cell line, MDPC-23. The expressions of thermo-TRP channels were examined using reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry, fluorometric calcium imaging. Analysis of RT-PCR revealed mRNA expression of TRPV1, TRPV2, TRPV4 and TRPM8, but no TRPV3, TRPA1. Immunohistochemical approach failed to detect TRPV1 expression. Whereas the application of 4-phorbol-12,13-didecanoate(10 μM, a TRPV4 agonist), menthol(1 mM, a TRPM8 agonist) and icilin(10 μM, a TRPM8 agonist) produced the enhancement of intracellular calcium concentration, capsaicin(1 μM, a TRPV1 agonist) did not. Our results suggest that subfamily of thermo-TRP channels expressed in odontoblasts may serve as thermal or mechanical transducer in teeth.

We present JHK-band near-infrared photometry of the star clusters in the dwarf irregular galaxy IC 5152. After excluding possible foreground stars, a number of candidate star clusters are identified in the near-infrared images of IC 5152, which include young populations. Especially, five young star clusters are identified in the(J-H, H-K) two color diagram and the total extinction values toward these clusters are estimated to be Av=2-6 from the comparison with the theoretical values given by the Leitherer et al.(1999)'s theoretical star cluster model.

In Korea, the ozone profiles have been acquired by using ozonesonde at Pohang station of the Korea Meteorological Administration (KMA) since 1995. These ozone soundings were performed at 0500 UTC on a weekly basis (every Wednesday) in a clear sky. The ozonesonde is equipped with the model 5A ECC sensor, which is one of the most common ozonesonde systems. There have been no attempts to evaluate the Pohang ozonesonde profiles compared with satellite. This paper will provide the first evaluation results for the ozonesonde profiles against HALogen Occultation Experiment (HALOE) measurements over Korea. During 1995-2004 periods, a total of 450 and 188 ozone profiles were obtained from the ozonesonde measurements from HALOE measurements over Korea, respectively. Hence, a total of 34 coincident profile pairs are extracted. Among those total profiles, 26 profiles from ozonesonde are compared against nearly coincident HALOE measurements in time and space. For ozone profiles, the results of statistical analyses showed that the best agreement between two measurements occurs in the 20-25 km and 30-35 km region, where the mean and RMS percent differences are less than ±5 and 14%, respectively. For temperature profiles, the mean and RMS percent differences in 20-25 km region are estimated to be about -0.1 and 1.7%, respectively. According to the scatter plots between two measurements, ozone data are strongly correlated each other above 20 km altitude range with more than 0.8 correlation coefficients. It is found that the altitude (pressure level) differences between two measurements would mainly lead to the discrepancy (over 40% below 18 km) below 20 km in ozone profiles.

Porous carbon materials were prepared with a thermal treatment of coal tar pitch at 550 in the Ar gas. Growth, merger, and distribution of pore were characterized with scanning electron microscopy as variation ascending temperature gradient and chamber pressure. After graphitizing at the 2600 (1 hr.), walls and connecting parts between pores were investigated with X-ray diffraction patterns. Wall thickness and pore size decreases as increasing ascending temperature gradient, and pore size becomes homogeneous. Graphite quality and thermal conductivity become higher due to the enhanced orientation of walls and connecting parts between pores.

Carbon-coated TiO2 was prepared by CCl4 solvent mixing method with the different heat treated temperatures (HTTs). Since the carbon layers derived from pitch on the TiO2 particles were porous, the carbon-coated TiO2 sample series showed a good adsorptivity. The values of BET surface areas measured were shown independently on the HTTs. The surface states by SEM present to the characterization of porous texture on the carbon-coated TiO2 sample and carbon distributions on the surfaces. From XRD data, PT700 and PT750 were shown the X-ray diffraction patterns of the anatase TiO2, but PT800 and PT850 were kept anatase-type structure even after heating at 800℃, though small amount of the rutile-type structure appears. The results of EDX microanalyses were observed for each sample show the spectra corresponding to almost all samples similar to C, O and Ti elements with an increase of HTTs. Finally, the excellent photoactivity of carbon-coated TiO2 (especially, PT700 and PT750) could be attributed to the homogeneous coated carbon on the external surface and the structural anatase phase.

This paper reports the application of Wood's national policy framework (Wood, 2002) to the use of computers in Chinese schools in order to evaluate the impact of and reaction to information and communications technology (ICT) policy on the future of schooling and society. With its highly centralized system of schooling, the "centralized regulation of schooling" scenario is considered to be sufficiently close to enable current ICT policy and possible future developments to be examined. The analysis arising/rom Wood's framework has significant implications for developing countries, such as China, which have limited funding and experience to address the range of issues relating to ICT integration. 81

Among Information Communication Technology (ICT) applications in education, Project-based Learning (PBL) is regarded as an effective intervention in the area of science and technology education. In this article, we present PBL classroom experiments using robot-oriented concepts to motivate students' interests describing what they do in PBL classes, how they create their ideas and products, and how their attitudes toward robot use have changed.