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Supercritical carbon dioxide(S-CO2) Brayton cycle has great development potential in the field of efficient utilization of clean energy represented by fourth-generation nuclear energy and solar energy. A reasonable and reliable control strategy is the key to ensure the safe, stable, efficient and flexible operation of the S-CO2 Brayton cycle system. This paper summarized the characteristics of S-CO2 Brayton cycle control, and summarized and compared the S-CO2 Brayton cycle control strategies under different application scenarios. The results show that the key control strategies of S-CO2 Brayton cycle include running state control, impeller machine control, heat source control, etc. The variable load control strategies mainly include volume control, turbine bypass control, turbine inlet throttle control, compressor speed control, etc. The analysis results provide a reference for the selection of S-CO2 Brayton cycle control strategies in related power generation fields.

In 2018, to help undergraduate medical students strengthen their self-learning and scientific research skills, we introduced an instructional model that combined literature-based learning with experimental design. We tested this model on the molecular biology class at Tongji University. In the first step of the model, a topic is chosen, and students find, read, and evaluate scientific papers in groups and deliver presentations. In the second step, they design scientific experiments in groups and discuss their proposed experiments in class, which is to be followed by further experimental verification in the lab course. This entire activity was given 20% weightage in the final score. The model led to better student-centered teaching and self-directed learning according to quantitative and qualitative assessment. Students showed great interest in literature and research. They enjoyed group work and gained experience in organization and presentation. Apart from a significant increase in final score, assessment data from students indicated that they were satisfied with this teaching model and considered it a positive experience. Looking at the positive impact of the literature-based learning and experiment design model, we support its continued use for teaching molecular biology to undergraduate medical students.

Understanding the liver stem cells (LSCs) holds great promise for new insights into liver diseases and liver regeneration. However, the heterogenicity and plasticity of liver cells have made it controversial. Here, by employing single‐cell RNA‐sequencing technology, transcriptome features of Krt19+ bile duct lineage cells isolated from Krt19CreERT; Rosa26R‐GFP reporter mouse livers are examined. Distinct biliary epithelial cells which include adult LSCs, as well as their downstream hepatocytes and cholangiocytes are identified. Importantly, a novel cell surface LSCs marker, CD63, as well as CD56, which distinguished active and quiescent LSCs are discovered. Cell expansion and bi‐potential differentiation in culture demonstrate the stemness ability of CD63+ cells in vitro. Transplantation and lineage tracing of CD63+ cells confirm their contribution to liver cell mass in vivo upon injury. Moreover, CD63+CD56+ cells are proved to be activated LSCs with vigorous proliferation ability. Further studies confirm that CD63+CD56− quiescent LSCs express VEGFR2 and FGFR1, and they can be activated to proliferation and differentiation through combination of growth factors: VEGF‐A and bFGF. These findings define an authentic adult liver stem cells compartment, make a further understanding of fate regulation on LSCs, and highlight its contribution to liver during pathophysiologic processes. [ABSTRACT FROM AUTHOR]

Recently, Chinese medical education has exhibited a shifting trend from teacher-centered instruction to student-centered learning, which usually includes a self-directed learning process. Providing students with high-quality and appropriate supplemental resources is necessary for their self-directed learning. This study aimed to investigate the appropriateness of AccessMedicine, an online medical resource, for first-year medical students at Tongji University in China. In the randomized controlled trial, 42 students were stratified by gender and grade point average (GPA) and randomly assigned to either the control group or AccessMedicine group. The students' learning outcomes were assessed with quizzes, including tests before and after learning and a final examination. Paired "t"-tests and two-way analysis of variance were performed for statistical analysis. We found that AccessMedicine-assisted learning improved student performance on tests and decreased the overall failure rate in the final examination. Further analysis showed that the final examination score of the subgroup with high GPAs in the AccessMedicine group significantly increased, but not that of the subgroup with low GPAs, indicating that AccessMedicine-assisted learning was more beneficial for good students than for poor students. A survey showed that professional vocabularies were the greatest obstacles to learning with AccessMedicine. Moreover, English language skills greatly affected the students' learning outcomes for the English resource but not those for the Chinese resource. Taken together, our results demonstrated that AccessMedicine was appropriate for Chinese medical education and improved the learning outcomes of students, especially students with high GPAs and a good command over the English language.

Stem cells are cells that can self-renew and differentiate into a variety of cell types under certain conditions. Stem cells have great potential in regenerative medicine and cell therapy for the treatment of certain diseases. To deliver knowledge about this frontier in science and technology to medical undergraduate students, we designed an innovative practical experiment for freshmen in their second semester. The lab exercise focused on rat bone marrow mesenchymal stem cell (BMSC) isolation, cell culture and differentiation, and it aimed to help students master the aseptic techniques for cell culture, the basic methods and procedures for the primary culture and passage of BMSCs, the basic procedure for the directional differentiation of BMSCs into adipocytes and their subsequent identification by oil-red-O staining. This lab exercise is a very meaningful and useful introduction to stem cell collection and manipulation and inspires medical students to deepen their understanding of translational medicine and regenerative medicine.

Biochemistry and cellular biology courses for medical students at Tongji University include the assessment that provides students with feedback to enhance their learning, which is a type of formative assessment. However, frequent instant feedback and guidance for students is often absent or inconsistently included in the teaching process. WeChat, the most popular Chinese social media, was introduced in biochemistry and cellular biology course. A WeChat official account (OA) was set up as an instant interactive platform. Over a period of two semesters, OA sent 73 push notifications. The components included course notices, preclass thought questions, after-class study materials, answer questions and feedback, simulation exercises, teacher-student interaction, and research progress relevant to the course. WeChat OA served as an active-learning teaching tool, provided more frequent feedback and guidance to students, and facilitated better student-centered communication in the teaching process. Using the WeChat OA in medical teaching emphasized interactive, interoperable, effective, engaging, adaptable, and more participatory teaching styles. As a new platform, WeChat OA was free, Internet-reliant, and easily managed. Using this new medium as a communication tool accelerated further advancement of instant feedback and improvement in teaching activities. Notifications and interactive feedback via the mobile social medium WeChat OA anytime and anywhere facilitated a student-centered teaching mode. Use of WeChat OA significantly increased the proportion of students interactively participating and resulted in a high degree of student satisfaction.

In view of problem that it is difficult to accurately locate device failure of inverter, a fault tolerance topology of three-level four-leg NPC inverter was proposed. In the topology, short-circuit fault and open-circuit fault can be located accurately by switching device used when topology changes, so as to provide a basis for fault-tolerant control of inverter. The topology enables half-leg replacement, and can achieve fault-tolerant control of up to three inverter legs at the same time.