Growth is a fundamental and vital characteristic of abalone, regulated by both cell number and size, and modulated by growth-related genes. The mollusk-like growth factor (MLGF) is a secreted protein that plays a key role in the growth and development of Pacific abalone. In this study, the growth-specific expression of Hdh-MLGF were analyzed under different conditions commonly encountered by Pacific abalone in aquaculture systems. The expression of Hdh-MLGF varied significantly with growth patterns, showed higher expression in rapid-growing individuals and lower expression in slow-growing abalone. Under starvation conditions, Hdh-MLGF expression was downregulated as the duration of starvation progressed. Under thermal stress, Hdh-MLGF expression increased during the first 12 hours at 25 °C stress. However, at 30 °C, the highest expression was recorded after 6 hours of thermal stress. These results provide valuable insights for future research on this growth factor in abalone and its aquaculture management.

In this study, Ti powder was fabricated from Ti scrap by a hydrogenation-dehydrogenation (HDH)method. The Ti powders were compacted by Spark plasma sintering (SPS) and the microstructure andmechanical properties of the powders were investigated. A hydrogenation reaction of Ti scrap occurred attemperatures near 450oC with a sudden increase in the reaction temperature and a decrease in the pressureof the hydrogen gas as measured in a furnace during the hydrogenation process. In addition, a dehydrogenationprocess was carried out at 750oC for 2hrs in a vacuum of 10-4torr. The Ti powder sizes obtained byhydrogenation-dehydrogenation and mechanical milling processes were in the range of 1~90µm and 1~100µm,respectively. To fabricate Ti compacts, Ti powders were sintered under an applied uniaxial punch pressure of40 MPa at in a range of 900~1200oC for 5 min. The relative density of a SPSed compact was 99.6% at 1100oC,and the tensile strength decreased with an increase in the sintering temperature. However, the hardnessincreased as the sintering temperature increased.