We have previously reported in this journal that the increase in Ca/Mg ratio and the aging of cells promote calcication of cultured normal human fibroblasts (NB1 cells). In this report, it is suggested that A-wave ultraviolet rays (UVA) induces calcification of NB1 cells even if the Ca/Mg ratio in culture medium is well balanced as 2. Furthermore, we have discovered that deep seawater (DSW) suppresses the calcication induced by UVA irradiation. In addition, suppressive effect of DSW was much higher than that of SSW. From these results, it was suggested that the suppressive eect of DSW on calcification in NB1 cells was caused by specific components included in DSW.

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The spray flash desalination system continues to attract the interest of researchers owing to its application in ocean thermal energy conversion. The system consists of a flash chamber, fresh water tank, vacuum pump, and plate type condenser. The desalination system requires a plate type condenser with good performance in order to improve overall system performance. The material used for the heat transfer plate of the condenser is usually titanium. However, the use of another material, such as aluminum alloy, is proposed by the author to achieve cost reduction and improve heat transfer performance. Furthermore, a special coating aluminum alloy plate is proposed as material for plate condenser of spray flash desalination system because the aluminum alloy has low corrosion resistance against seawater. In this study, the heat transfer performance of the material and its corrosion against seawater were investigated using deep and surface sea water of Kume island of Okinawa Prefecture. The plate heat exchanger incorporates three kinds of aluminum alloy plate coating, and its overall heat transfer coeficients under flowing seawater were derived. The three coating materials are 25 μm and 100 μm thick PEEK and 5 μm WIN KOTE®, respectively. In addition, evaluation test for heat transfer and corrosion test of the heat exchanger under owing seawater were also conducted for a five months period. Results show that out of the three materials, the 25 μm-thick PEEK coating plate had the largest overall heat transfer coeficient. The overall heat transfer of the three materials did not change during the five months test period. However, only the WIN KOTE® coating plate corroded owing to corrosion effects of the seawater.

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The deep ocean water (DOW) which has low temperature and high nutrients will be effective for regenerating subpolar/temperate seaweed bed and aquaculture of those seaweeds. In the present study, a semi-enclosed small fishing port near the pumping facility of DOW in Kume Island of Okinawa in Japan is chosen for the field experiment of seaweed bed development, because it could be possible to prevent the discharged DOW from diffusing rapidly. Additionally, in order to keep low temperature and high nutrient concentration of DOW more effectively, a box-shaped pool is installed on the bottom of the port in which DOW is discharged. In the field experiment, water temperature and nutrients concentrations in and out of the pools, and current velocity just above the top of the pool have been measured to detect the behaviour of discharged DOW. Through the field experiment, it is clarified that the box-shaped pool installed on the bottom of the port is quite effective to retain the discharged DOW. It is also found that DOW hardly affect surrounding environment since it will rapidly mix with ambient seawater when it goes out of the pool.

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