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Diabetic nephropathy is one of the most common complications of diabetic microangiopathy, which significantly reduces the quality of life of diabetic patients and is the main cause of end-stage renal failure. As one of the main drugs in the treatment of diabetes mellitus, metformin plays a vital role in the treatment of diabetic nephropathy. In recent years, studies have found that metformin can not only lower blood sugar through a variety of mechanisms, but also prevent diabetic kidney disease from developing into end-stage renal failure. Several studies have found that metformin has clinical efficacy in the treatment of diabetic nephropathy, and drug safety in patients should be evaluated by glomerular filtration rate. This review summarizes the results of the clinical effects and mechanism of metformin in the treatment of diabetic nephropathy, aiming to better understand the therapeutic effect of metformin on diabetic nephropathy, and provide reference for the treatment of diabetic nephropathy.

Besides improving students' understanding of scientific concepts, chemistry teaching should also improve students' ability of applying concepts to solve problems. The research aims to explore the effects of modeling teaching on students' proficiency in solving galvanic cell problems. This research used a quasi-experimental design, and the independent variable of the research was the teaching method. Forty-five students in the experimental class received modeling teaching, and 48 students in the control class received lecture-style teaching. The dependent variable was the performance level of the student's ability to solve the problem of the galvanic cell, which was evaluated using the galvanic cell proficiency assessment tool. The research results show that the students in the experimental class were significantly more proficient in solving galvanic cell problems than those in the control class. The results of unstructured interviews assisted in illustrating the role of modeling teaching in improving the proficiency of students in solving galvanic cell problems, and students in the experimental class had positive views on modeling teaching.

Multiple endocrine adenomatosis type 2A (MEN2A) is a subtype of multiple endocrine adenomatosis type 2, which is clinically characterized by medulloid thyroid carcinoma (MTC) , pheochromocytoma (PHEO) , and hyperparathyroidism, and has been reported to be caused by mutations in the RET proto-oncogene on chromosome 10. We reported a case of MEN2A caused by RET proto-oncogene C634Y mutation, and conducted a pedigree analysis of the patient. Genetic test results showed C634Y mutation in the patient's siblings and their offspring. The diagnosis and treatment of this case in combination with a review of the relevant literature suggest that endocrine gland tests and RET proto-oncogene test should be performed for a patient diagnosed with endocrine adenomatosis to reduce the possibility of misdiagnosis and missed diagnosis, and to achieve early treatment, improve the effect of treatment and the prognosis of patients. In addition, the first- and second-degree relatives of the patient should also be tested for the mutation of the RET proto-oncogene.

Background: In many countries and regions, such as the United States, Europe and China, a trend has emerged in which students' enthusiasm for STEM is declining. This decline may be related to students' lack of science self-efficacy. An accurate examination of students' science self-efficacy can provide a research foundation for how to cultivate it. This paper used mixed methods to develop a valid science self-efficacy scale for high school students, focusing on the perceived competence dimension. A cross-sectional analysis exploring and interpreting differences across grades and genders in science self-efficacy among high school students was conducted. Subsequently, a 1-year longitudinal study was conducted on the development of science self-efficacy in China. Results: This study developed a 24-item science self-efficacy instrument based on the Rasch model, and the validity of the instrument was assessed through multiple aspects, including face, content, construct, and predictive validity. This instrument was used to divide students' science self-efficacy into four different levels. A cross-sectional study examining 1564 high school students in 10th--12th grades revealed that students' science self-efficacy exhibited a complex process of decreasing and then increasing by grade. Most girls' science self-efficacy was higher than that of boys for Levels 1 and 4, while for the intermediate levels, i.e., Levels 2 and 3, most boys had higher science self-efficacy than girls. The quantitative and qualitative results of the longitudinal study through a 1-year follow-up of 233 high school students indicated that students' science self-efficacy significantly improved. We revealed inconsistencies between cross-sectional and longitudinal studies of the change in science self-efficacy from 10 to 11th grade. Conclusion: This study makes many contributions. First, we developed a science self-efficacy measurement instrument for high school students with high reliability and validity based on the Rasch model and characterized four different levels of student science self-efficacy. Second, the gender differences in science self-efficacy and the complex changes among grades were explained from the perspective of science self-efficacy level. Finally, students' science self-efficacy significantly improved in the longitudinal study, which was explained by self-efficacy theory and the Chinese core competency-oriented science curriculum.

The galvanic cell is a basic concept in electrochemistry. To assess mainland Chinese students' proficiency levels in galvanic cells, the Galvanic Cell Proficiency Level Assessment (GCPA) was developed based on the Rasch model. The GCPA was developed through a pilot test and consists of seven multiple-choice questions and four open questions. The assessment instrument was administered to 621 high school students in the 11th grade, and the test results showed good reliability and validity. The interview results supported the validity of the data generated by the instrument.

It is expected that the activity of photocatalysts can remain the same or decrease as little as possible in photocatalysis reaction. Herein, for the first time, a self‐accelerating H2 production activity in a noble‐metal‐free Cu2O/TpPa‐2‐COF photocatalyst is reported. It shows a beginning H2 production rate of 4.41 mmol h−1 g−1 under visible light illuminance, while the activity kept increasing to 27.27 mmol h−1 g−1 after 25 h reaction, which is 6.2 times higher than the beginning activity and reaches a record high. It is confirmed that part of Cu2O in Cu2O/TpPa‐2‐COF in situ transformed to Cu0 in photocatalytic reaction, which acting as cocatalyst promotes the separation of photogenerated charge carriers. Further density functional theory calculations demonstrate that the Schottky barrier height of Cu‐Cu2O (111) interface is much smaller than that of Pt‐Cu2O (111), supporting its more efficient effect than that with Pt as cocatalyst. [ABSTRACT FROM AUTHOR]

Proton exchange membrane fuel cells (PEMFCs) and alkaline membrane fuel cells (AEMFCs) have received great attention as energy devices of the next generation. Accelerating oxygen reduction reaction (ORR) kinetics is the key to improve PEMFC and AEMFC performance. Platinum‐based catalysts are the most widely used catalysts for the ORR, but their high price and low abundance limit the commercialization of fuel cells. Non‐noble metal‐nitrogen‐carbon (M−N−C) is considered to be the most likely material class to replace Pt‐based catalysts, among which Fe−N−C and Co−N−C have been widely studied due to their excellent intrinsic ORR performance and have made great progress in the past decades. With the improvement of synthesis technology and a deeper understanding of the ORR mechanism, some reported Fe−N−C and Co−N−C catalysts have shown excellent ORR activity close to that of commercial Pt/C catalysts. Inspired by the progress, regulation strategies for Fe−N−C and Co−N−C catalysts are summarized in this Review from 5 perspectives: (1) coordinated atoms, (2) environmental heteroatoms and defects, (3) dual‐metal active sites, (4) metal‐based particle promoters, and (5) curved carbon layers. We also make suggestions on some challenges facing Fe−N−C and Co−N−C research. [ABSTRACT FROM AUTHOR]

The single‐atom Fe−N−C is a prominent material with exceptional reactivity in areas of sustainable energy and catalysis research. It is challenging to obtain the dense Fe‐N4 site without the Fe nanoparticles (NPs) sintering during the Fe−N−C synthesis via high‐temperature pyrolysis. Thus, a novel approach is devised for the Fe−N−C synthesis at low temperatures. Taking FeCl2 as Fe source, a hydrogen environment can facilitate oxygen removal and dichlorination processes in the synthesis, efficiently favouring Fe‐N4 site formation without Fe NPs clustering at as low as 360 °C. We shed light on the reaction mechanism about hydrogen promoting Fe‐N4 formation in the synthesis. By adjusting the temperature and duration, the Fe‐N4 structural evolution and site density can be precisely tuned to directly influence the catalytic behaviour of the Fe−N−C material. The FeNC‐H2‐360 catalyst demonstrates a remarkable Fe dispersion (8.3 wt %) and superior acid ORR activity with a half‐wave potential of 0.85 V and a peak power density of 1.21 W cm−2 in fuel cell. This method also generally facilitates the synthesis of various high‐performance M−N−C materials (M=Fe, Co, Mn, Ni, Zn, Ru) with elevated single‐atom loadings. [ABSTRACT FROM AUTHOR]

Iron‐nitrogen‐carbon (Fe‐N‐C) catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) have seriously been hindered by their poor ORR performance of Fe‐N‐C due to the low active site density (SD) and site utilization. Herein, we reported a melamine‐assisted vapor deposition approach to overcome these hindrances. The melamine not only compensates for the loss of nitrogen caused by high‐temperature pyrolysis but also effectively etches the carbon substrate, increasing the external surface area and mesoporous porosity of the carbon substrate. These can provide more useful area for subsequent vapor deposition on active sites. The prepared 0.20Mela‐FeNC catalyst shows a fourfold higher SD value and site utilization than the FeNC without the treatment of melamine. As a result, 0.20Mela‐FeNC catalyst exhibits a high ORR activity with a half‐wave potential (E1/2) of 0.861 V and 12‐fold higher ORR mass activity than the FeNC in acidic media. As the cathode in a H2‐O2 PEMFCs, 0.20Mela‐FeNC catalyst demonstrates a high peak power density of 1.30 W cm−2, outstripping most of the reported Fe‐N‐C catalysts. The developed melamine‐assisted vapor deposition approach for boosting the SD and utilization of Fe‐N‐C catalysts offers a new insight into high‐performance ORR electrocatalysts. [ABSTRACT FROM AUTHOR]