Engineering topics
Publications and source records attributed to Yuan, Xin.
Na-doped BiFeO 3 demonstrates an enhanced p-type behavior compared to p-type BiFeO 3 prepared without extrinsic dopants, and Na-doped BiFeO 3 can serve as a photocathode for solar O 2 reduction to H 2 O 2 when coupled with Ag nanoparticle catalysts.
A project funded by the National Science Foundation, Computer Science Integrated with Mathematics in Middle Schools (CSIMMS) (DRL-1640039), brought middle-school mathematics teachers together with university computer science (CS) faculty and STEM education faculty to design, develop, and test curriculum modules in which CS is integrated into instruction for middle-school general-mathematics courses. The project developed integrated math/CS curriculum modules (for grades 6, 7, and 8), complete with student tasks and teacher materials to guide classroom implementation. Across the project, sixteen teachers from four middle schools representing different school contexts (both urban and suburban, serving students from a range of demographic and socioeconomic backgrounds) participated as members of the design team and trial testers of the math/CS modules. All modules underwent multiple years of testing and refinement, with extensive input from the teachers who co-designed and implemented them. Approximately 50-100 middle-school students participated in the classes of those who taught each year. The modules in this volume feature a range of models for integrating mathematics and computer science at the 6th and 7th grade levels. All modules foreground the teaching of grade-level mathematics content, with computer science functioning to motivate and/or reinforce these ideas.
Abstract Hydrogenation and hydrogenolysis are two important reactions for electrochemical reductive valorization of biomass‐derived oxygenates such as 5‐hydroxymethylfurfural (HMF). In general, hydrogenolysis (which combines hydrogenation and deoxygenation) is more challenging than hydrogenation (which does not involve the cleavage of carbon–oxygen bonds). Thus, identifying factors and conditions that can promote hydrogenolysis is of great interest for reductive valorization of biomass‐derived oxygenates. For the electrochemical reduction of HMF and its derivatives, it is known that aldehyde hydrogenation is not a part of aldehyde hydrogenolysis but rather a competing reaction; however, no atomic‐level understanding is currently available to explain their electrochemical mechanistic differences. In this study, combined experimental and computational investigations were performed using Cu electrodes to elucidate the key mechanistic differences between electrochemical hydrogenation and hydrogenolysis of HMF. The results revealed that hydrogenation and hydrogenolysis of HMF involve the formation of different surface‐adsorbed intermediates via different reduction mechanisms and that lowering the pH promoted the formation of the intermediates required for aldehyde and alcohol hydrogenolysis. This study for the first time explains the origins of the experimentally observed pH‐dependent selectivities for hydrogenation and hydrogenolysis and offers a new mechanistic foundation upon which rational strategies to control electrochemical hydrogenation and hydrogenolysis can be developed.
It has been demonstrated that the T-box family transcription factor 18 (Tbx18) -positive cells give rise to renal mesenchymal cells and contribute to the development of the urinary system. However, it is unclear whether Tbx18-positive cells are the origin of the myofibroblasts during renal fibrosis. The present study aimed to determine the contribution of Tbx18-positive cells in kidney fibrosis and their underlying mechanism. We show that Tbx18-positive cells contribute to the development of the urinary system, especially renal fibroblasts. Following unilateral ureteral obstruction (UUO), genetic fate tracing results demonstrated that Tbx18-positive cells not only proliferate but also expand and differentiate into fibroblasts and myofibroblasts, indicating that they may act as profibrotic progenitors. Cell culture results suggest that transforming growth factor (TGF)-β promotes Tbx18-positive cells differentiation into myofibroblasts and assist their contribution to kidney fibrosis. Overall, the present study demonstrated that Tbx18-positive cells may act as profibrotic progenitor cells in a pathological condition of UUO-induced injury. Moreover, TGF-β may play a role in differentiation of Tbx18-positive cells into myofibroblasts in kidney fibrosis. These findings may provide a potential target on Tbx18-positive myofibroblast progenitors in the treatment of renal fibrosis.
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