Search

ABSTRACTIn a close Brayton cycle power system, a high-temperature gas cooled reactor (HTGR) turbine operating with specialized working fluid is the major component. Carbon dioxide and noble gases have quite different physical properties compared to air. This makes the performance evaluation methods for air turbine unable to evaluate carbon dioxide and noble gases turbines. In this paper, physical parameters of working fluid influencing turbine cascade performance are identified. The correlation of turbine cascade loss with different working fluids is investigated by using theoretical analysis and numerical validation. Special focus is on the relationship amid total pressure loss coefficient in a turbine cascade and working fluids’ specific heat ratios. The results show that the correlation equation between the turbine cascade total pressure loss coefficient and the specific heat ratio of working fluid obtained in this paper can accurately predict the total pressure loss coefficient for other working fluids or in other working conditions according to the existing data.

Despite recent advances in crop metabolomics, the genetic control and molecular basis of wheat kernel metabolomes at different developmental stages remain largely unknown. Here, we performed a widely-targeted metabolic profiling in kernels at three developmental stages, namely grain filling kernels (FK), mature kernels (MK) and germinating kernels (GK), using a population of 159 recombinant inbred lines (RILs). A total of 625 annotated metabolites were detected, and 3173, 3143 and 2644 metabolite quantitative trait loci (mQTL) were mapped in FK, MK and GK, respectively. Only 52 mQTL were simultaneously mapped in all three stages, indicating a high stage-specificity of the wheat kernel metabolome. Subsequently, four candidate genes were functionally validated by in vitroenzymatic reactions and/ or transgenic approaches in wheat, with three of these mediating the tricin metabolic pathway. Meanwhile, both metabolite flux efficiencies within the tricin pathway and the superior candidate haplotypes were evaluated. Thus, the current work represents a comprehensive delineation of the pathway of tricin metabolism in wheat. Finally, further wheat metabolic pathways were re-constructed by updating them to incorporate the 177 candidates identified in the current study. To this end, our work not only provides new knowledge on wheat kernel metabolome variations, but also identifies important molecular resources for wheat nutritional quality improvement.

Background: Seed oil content is an important agronomic trait of Brassica napus(B. napus), and metabolites are considered as the bridge between genotype and phenotype for physical traits. Results: Using a widely targeted metabolomics analysis in a natural population of 388 B. napusinbred lines, we quantify 2172 metabolites in mature seeds by liquid chromatography mass spectrometry, in which 131 marker metabolites are identified to be correlated with seed oil content. These metabolites are then selected for further metabolite genome-wide association study and metabolite transcriptome-wide association study. Combined with weighted correlation network analysis, we construct a triple relationship network, which includes 21,000 edges and 4384 nodes among metabolites, metabolite quantitative trait loci, genes, and co-expression modules. We validate the function of BnaA03.TT4, BnaC02.TT4, and BnaC05.UK, three candidate genes predicted by multi-omics analysis, which show significant impacts on seed oil content through regulating flavonoid metabolism in B. napus. Conclusions: This study demonstrates the advantage of utilizing marker metabolites integrated with multi-omics analysis to dissect the genetic basis of agronomic traits in crops.