The absolute age of lapilli tuff in sedimentary formation that contains dinosaur fossils in the Boseong area, Korea was determined radiometrically against volcanic rocks below and above the fossil-bearing horizons. The sanidine in the lapilli tuff below the fossil-bearing horizon (Seonso formation) has an 40Ar-39Ar age of 81.l±1.4Ma. The Pilbong tuff above Seonso formation has an 40Ar-39Ar age of 81.0±2.4Ma. An andesite dyke intruding all sedimentary units yields an 40Ar-39Ar age of 42.4±2.5Ma. Thus 81 Ma age can be regarded as the best estimate for the age of the Seonso Formation and the associated the dinosaur eggs. This age correlates well with dinosaur fossil finds in the Haenam and Koseong regions of Korea. The occurrence of dinosaur eggs and clutches attests to the existence of dinosaurs in southern Korea at least inCampanian times.

Embryonic stem cells have a pluripotency and a potential to differentiate to all type of cells. In our previous study, we have shown that embryonic stem cells (ESCs) lines can be generated from murine parthenogenetic embryos. This parthenogenetic ESCs line can be a useful stem cell source for tissue repair and regeneration. The defect in full-term development of parthenogenetic ESCs line enables researchers to avoid the ethical concerns related with ESCs research. In this study, we presented the results demonstrating that parthenogenetic ESCs can be induced into osteogenic cells by supplementing culture media with ascorbic acid and β-glycerophosphate. These cells showed morphologies of osteogenic cells and it was proven by Von Kossa staining and Alizarin Red staining. Expression of marker genes for osteogenic cells (osteopontin, osteonectin, alkaline phosphatase, osteocalcin, bone-sialoprotein, collagen type1, and Cbfa1) also confirmed osteogenic potential of these cells. These results demonstrate that osteogenic cells can be generated from parthenogenetic ESCs in vitro.

The endogenous retrovirus-like elements (HERVs) found on several human chromosomes are somehow involved in gene regulation, especially during the transcription level. HERV-H, located on chromosome Xp22, may regulate gastrin-releasing peptide receptor (GRPR) in connection with diverse diseases. By suppression subtractive hybridization screen on SV40-immortalized lung fibroblast (WI-38 VA-13), we discovered that expression of HERV-HX2, a clustered HERV-H sequence on chromosome X, was upregulated in immortalized lung cells, compared to that of normal cells. Expression of HERV-HX2 was then analyzed in various cell lines, including normal somatic cells, cancer cells, SV40-immortalized cells, and undifferentiated and differentiated human embryonic stem cells. Expression of HERV-HX2 was specifically upregulated in continuously-dividing cells, such as cancer cells and SV40-immortalized cells. Especially, HERV-HX2 in HeLa cells was highly upregulated during the S phase of the cell cycle. Similar results were obtained in hES cells, in which undifferentiated cells expressed more HERV-HX2 mRNA than differentiated hES cells, including neural precursor and endothelial progenitor cells. Taken together, our results suggest that HERV-HX2 is upregulated in cancer cells and undifferentiated hES cells, whereas downregulated as differentiation progress. Therefore, we assume that HERV-HX2 may playa role on proliferation of cancer cells as well as differentiation of hES cells in the transcriptional level.

As a continuation of a previous work by Park et al. (2006), we have developed a two-element radio interferometer that can measure both the phase and amplitude of a visibility function. Two small radio telescopes with diameters of 2.3 m are used as before, but this time an external reference oscillator is shared by the two telescopes so that the local oscillator frequencies are identical. We do not use a hardware correlator; instead we record signals from the two telescopes onto a PC and then perform software correlation. Complex visibilities are obtained toward the sun at λ=21cm for 24 baselines with the use of the earth rotation and positional changes of one element, where the maximum baseline length projected onto UV plane is ~90λ As expected, the visibility amplitude decreases with the baseline length, while the phase is almost constant. The image obtained by the Fourier transformation of the visibility function nicely delineates the sun, which is barely resolved due to the limited baseline length. The experiment demonstrates that this system can be used as a "toy" interferometer at least for the education of (under)graduate students.

The study was conducted to gather basic information on the occurrence of phytophagous nematodes for the establishment of nematode management strategy in major highland crop production such as chinese cabbage, carrot and potato. Soil samples were collected from five areas in 48 fields in the highland and sub-highland (425m to 1136m asl) areas in 2006. Majority (88%) of the soil samples contained the root-knot nematodes, Meloidogyne hapla. The average density of the root-knot nematodes in chinese cabbage, carrot and potato fields were 8.3, 18.0 and 25.9 nematodes/100g soil, respectively. Helicotylenchus sp., Pratylenchus sp. and Dorylaimida sp. were also detected but in low densities.Root-knot nematode damage was not detected in potato growth and harvest at 0, 2, 12, 23 nematodes/100g soil densities.