Swelling Properties of Water-Swelling Materials Exposed to Organic Water Pollution

A water-swelling material is one of the rubbery impermeable materials which mixed synthetic resin elastomers as a base material, high absorbency polymers, filler and solvents. In this study, swelling characteristics of the water-swelling material on the water polluted with COD and BOD, as an impermeable material at coastal landfill sites, are examined by laboratory swelling ratio test. Furthermore, the factor in which it influences the swelling pressure of water-swelling material is clarified by measuring the swelling pressure. As the results, the COD nor the BOD concentrations in the soaked water influence the swelling ratio of the water-swelling material. When the thicknesses of water-swelling material are 2 mm and 3 mm, the maximum swelling pressure of 0.5 MPa or more that corresponds to hydraulic pressure by depth of 50 m is possessed

The Role of Paracrine and Autocrine Signaling in the Early Phase of Adipogenic Differentiation of Adipose-derived Stem Cells.

INTRODUCTION: High cell density is known to enhance adipogenic differentiation of mesenchymal stem cells, suggesting secretion of signaling factors or cell-contact-mediated signaling. By employing microfluidic biochip technology, we have been able to separate these two processes and study the secretion pathways. METHODS AND RESULTS: Adipogenic differentiation of human adipose-derived stem cells (ASCs) cultured in a microfluidic system was investigated under perfusion conditions with an adipogenic medium or an adipogenic medium supplemented with supernatant from differentiating ASCs (conditioned medium). Conditioned medium increased adipogenic differentiation compared to adipogenic medium with respect to accumulation of lipid-filled vacuoles and gene expression of key adipogenic markers (C/EBPα, C/EBPβ, C/EBPδ, PPARγ, LPL and adiponectin). The positive effects of conditioned medium were observed early in the differentiation process. CONCLUSIONS: Using different cell densities and microfluidic perfusion cell cultures to suppress the effects of cell-released factors, we have demonstrated the significant role played by auto- or paracrine signaling in adipocyte differentiation. The cell-released factor(s) were shown to act in the recruitment phase of the differentiation process

Environmental impact evaluation on construction of vertical cutoff walls in landfill sites

Steel pipe sheet pile cutoff walls built up by installing steel pipe sheet piles (SPSPs) in coastal waste landfill sites are important elements for preventing leakage of leaching from the reclaimed waste to the open sea. Adhesion with the peripheral ground has to be maintained in the installation of SPSPs for manifestation of the cutoff function of the SPSPs with joint sections. In this study, attention is paid to the disturbed area generated in the peripheral ground around the steel pipe sheet pile cutoff walls. Moreover, by using seepage and advection/dispersion analysis, we evaluated the impact of the disturbed area on the environmental preservation function of coastal waste landfill sites as a whole, the effect of the installation method which suppresses the formation of the disturbed area and the influence of soil improvement by the sand compaction pile method. One of the results of this study has shown that the disturbed area generated in the lower deposition clay layer greatly influences the quantity of leakage of toxic substances in a specific route. On the other hand, the installation of SPSPs by using soil cement, in which the soil improvement of the periphery ground is undertaken, is effective in suppressing the leakage of toxic substances

Leachate Control Technology Using H-Jointed Steel Pipe Sheet Piles with H-H Joints at Coastal Landfills

H-H joint of "H-jointed SPSP with H-H joint", which is made up of interlocking two H-steel sections of different sizes, is the one of SPSP’s joint to improve the hydraulic conductivity. "H-H jointed SPSP with H-H joint" is expected to be applied to a vertical cutoff wall in coastal landfill sites. In H-jointed SPSP with H-H joint, the H-joint is completely imperviousness. H-H joint, however, is pervious at interlocked state because a gap of 8 to 11 mm is left between the interlocking flanges, therefore, a water interception treatment must be conducted to seal the gap. The water shielding treatment of H-H joint is executed by coating the gaps with a water-swelling sheet of paint before its installation. Then, hollow space is generated in H-H joint after treating by water-swelling sheet, and that space can be used effectively. This paper proposes leachate control technologies using H-H joint interior space of SPSP cutoff walls. The possibility of those technologies and hydraulic conductivity of H-jointed SPSP with H-H joints are demonstrated by conducting the hydraulic conductivity test