The finite element analysis and calculation were performed for the blanket first-wall made of SiC/SiC composite material for Advanced Steady-state Tokamak Reactor 2, A-SSTR2, which at present is conceptually designed ...The finite element analysis and calculation were performed for the blanket first-wall made of SiC/SiC composite material for Advanced Steady-state Tokamak Reactor 2, A-SSTR2, which at present is conceptually designed in Naka Fusion research establishment, JAERI. Comparison analysis and design window were analyzed using the finite element code ADINA 7.4. Through a 2D calculation for various geometrical configurations and sensitive material properties, a fundamental guideline for the first wall and blanket design are established with respect to maximum temperature, thermal and mechanical stress for many configurations. To satisfy hydrodynamic requirement, a4d4 (the dimension of coolant channel is 4 mm x 8 mm, and the distance between neighboring channels is 4 mm) was chosen as a design point for high thermal conductivity up to 50 W/m.K. In order to find a good solution for lower conductivity, more elaborate work should be done in the future. Nonetheless, the outline of design window for a specific structural material is very useful for the future A-SSTR2 first wall design.展开更多
Somatostatin(SST),named for its ability to inhibit pituitary growth hormone(GH)secretion,is involved in multiple physiological processes though somatostatin receptors(SSTRs).Both in vitro and in vivo studies have demo...Somatostatin(SST),named for its ability to inhibit pituitary growth hormone(GH)secretion,is involved in multiple physiological processes though somatostatin receptors(SSTRs).Both in vitro and in vivo studies have demonstrated that SSTR2 mediates GH inhibition by SST.However,whether a deficiency of SSTR2 promotes the somatic growth of fish is unclear.In this study,both sstr2a and sstr2b were predominantly expressed in the pars distalis of the pituitary gland,with sstr2a showing higher expression levels than sstr2b.Mutation of sstr2a was performed in tilapia using the CRISPR/Cas9 system.The sstr2a^(-/-)mutants exhibited a significant increase in body weight at 60,120,and 180 days post fertilization(dpf)when reared in mixed populations with wild type(WT)fish,being 43%heavier than WT fish at 180 dpf.The sstr2a^(-/-)mutants also demonstrated better growth than WT fish under the separate-tank culture condition,with higher body weight,length,height,and width,weight gain rate,and specific growth rate,as well as lower food intake and feed coefficient,but no difference in condition factor.Furthermore,among female and male sstr2a^(-/-)mutants and WT controls,the growth of male sstr2a^(-/-)mutants was the highest,followed by female sstr2a^(-/-)mutants,then WT males and WT females.No differences were observed between sstr2a^(-/-) mutants and WT fish in the mean area and number of muscle fibers per visual field under the microscope.However,there were fewer lipid droplets in the liver in sstr2a^(-/-) mutants than in WT fish.The deficiency of SSTR2a also led to elevated circulating GH and IGF-1 levels and up-regulated expression of GH/IGF axis genes.Overall,the first established sstr2a^(-/-) mutant line in fish not only holds significant potential to develop into a fast-growth strain of tilapia,but also provides an excellent model for understanding the regulation of growth and metabolism in teleosts.展开更多
文摘The finite element analysis and calculation were performed for the blanket first-wall made of SiC/SiC composite material for Advanced Steady-state Tokamak Reactor 2, A-SSTR2, which at present is conceptually designed in Naka Fusion research establishment, JAERI. Comparison analysis and design window were analyzed using the finite element code ADINA 7.4. Through a 2D calculation for various geometrical configurations and sensitive material properties, a fundamental guideline for the first wall and blanket design are established with respect to maximum temperature, thermal and mechanical stress for many configurations. To satisfy hydrodynamic requirement, a4d4 (the dimension of coolant channel is 4 mm x 8 mm, and the distance between neighboring channels is 4 mm) was chosen as a design point for high thermal conductivity up to 50 W/m.K. In order to find a good solution for lower conductivity, more elaborate work should be done in the future. Nonetheless, the outline of design window for a specific structural material is very useful for the future A-SSTR2 first wall design.
基金funded by the National Key Research and Development Program of China(2022YFD1201600)China Agriculture Research System of MOF and MARA(CARS-46)+1 种基金National Natural Science Foundation of China(32473156,32373106 and 32172953)Chongqing Fishery Technology Innovation Union(CQFTIU202501-7).
文摘Somatostatin(SST),named for its ability to inhibit pituitary growth hormone(GH)secretion,is involved in multiple physiological processes though somatostatin receptors(SSTRs).Both in vitro and in vivo studies have demonstrated that SSTR2 mediates GH inhibition by SST.However,whether a deficiency of SSTR2 promotes the somatic growth of fish is unclear.In this study,both sstr2a and sstr2b were predominantly expressed in the pars distalis of the pituitary gland,with sstr2a showing higher expression levels than sstr2b.Mutation of sstr2a was performed in tilapia using the CRISPR/Cas9 system.The sstr2a^(-/-)mutants exhibited a significant increase in body weight at 60,120,and 180 days post fertilization(dpf)when reared in mixed populations with wild type(WT)fish,being 43%heavier than WT fish at 180 dpf.The sstr2a^(-/-)mutants also demonstrated better growth than WT fish under the separate-tank culture condition,with higher body weight,length,height,and width,weight gain rate,and specific growth rate,as well as lower food intake and feed coefficient,but no difference in condition factor.Furthermore,among female and male sstr2a^(-/-)mutants and WT controls,the growth of male sstr2a^(-/-)mutants was the highest,followed by female sstr2a^(-/-)mutants,then WT males and WT females.No differences were observed between sstr2a^(-/-) mutants and WT fish in the mean area and number of muscle fibers per visual field under the microscope.However,there were fewer lipid droplets in the liver in sstr2a^(-/-) mutants than in WT fish.The deficiency of SSTR2a also led to elevated circulating GH and IGF-1 levels and up-regulated expression of GH/IGF axis genes.Overall,the first established sstr2a^(-/-) mutant line in fish not only holds significant potential to develop into a fast-growth strain of tilapia,but also provides an excellent model for understanding the regulation of growth and metabolism in teleosts.
