Youn-Moon Park

Diosgenin stimulates osteogenic activity by increasing bone matrix protein synthesis and bone-specific transcription factor Runx2 in osteoblastic MC3T3-E1 cells☆

Diosgenin, a steroid saponin extracted from the root of wild yam (Dioscorea villossa) is claimed to have osteogenic property. However, detailed studies providing evidence to this claim have not been fully undertaken. In this study, we investigated the effect of diosgenin on the osteogenesis of murine MC3T3-E1 osteoblastic cells. Cells were cultured with varying levels of diosgenin (0-10 μM) within 25 days of bone formation period. Diosgenin was found to stimulate proliferation within the range of 0.01-5 μM using MTT assay. The medium and cellular levels of Type 1 collagen and alkaline phosphatase (ALP), both of which are major bone matrix proteins, increased within the low range of diosgenin concentration (>0-3 μM), and this pattern was further confirmed by collagen and ALP staining of the extracellular matrix (ECM). The cellular protein expression of ALP and collagen Type 1 was also increased at 0.1-1 μM diosgenin treatment as analyzed by Western blot. Calcium deposition within the ECM also showed the same pattern as assessed by Alizarin Red S and Von Kossa staining. Bone-specific transcription factor runt-related transcription factor 2 (Runx2) and Runx2-regulated osteopontin protein expressions were induced at low concentration (0.1-1 μM) and again decreased with high diosgenin concentrations. Based on our findings, our study suggests that diosgenin can enhance bone formation by stimulating the synthesis and secretion of Type 1 collagen and ALP and bone marker proteins Runx2 and osteopontin expression. The increased levels of these marker proteins, in turn, can increase the formation of calcium deposits within the ECM thereby increasing bone formation.

1-MCP application for horticultural commodities in Korea: Practical potential and future task

Abstract1-methylcyclopropene (1-MCP), a gaseous inhibitor of ethylene action, has been widely used in horticultural crops to maintain quality, especially for long-term storage. In fruits, 1-MCP treatment reduces ethylene evolution, softening, color change, and flavor production, thus preserving product quality. The treatment also reduces the incidence of physiological disorders induced during refrigerated storage of many fruits and vegetables. Recent studies of 1-MCP treatments on various horticultural produce provided precious information that can expand the potential of commercial utilization. Under various treatment conditions, different responses to 1-MCP treatments were elucidated according to crops, cultivars, and harvest maturity. At present in Korea, however, commercial use of 1-MCP is limited to apple industry. The limit of commercial use of 1-MCP may be mainly due to different responses to the treatment by harvest maturity and storage conditions. Besides, diverse postharvest programs according to the period of storage require more specific treatment conditions such as concentration, temperature and the duration of treatment. In the present review, relatively recent research results were summarized and, based on the findings, future tasks were proposed to expand commercial usefulness of 1-MCP treatment in more horticultural commodities.

Pattern density effect on interfacial bonding characteristics of Cu-Cu direct bonds for 3D IC packages

In this study, effect interfacial bonding strength on pattern density was evaluated. The Silicon oxide(SiO2) on parallel patterned Cu lines wafer can be removed by using a solution of buffered oxide etch and sulfuric acid (BOE/H2SO4) to improve the bonding quality of Cu-Cu pattern direct bonds. Two 8-inch Cu wafers were bonded at 400°C via the thermocompression method. The interfacial adhesion energy of Cu-Cu pattern direct bonding was quantitatively measured by the four-point bending method. After BOE for 2 min/H2SO4 for 1 min wet pretreatment, the interfacial adhesion energies with pattern density of 0.06, and 0.23 were 7.9, and 4.1 J/m2, respectively. Therefore, the CMP planarization is critical to have reliable bonding quality of Cu pattern direct bonds.