Developing an abnormal high-Na-content P2-type layered oxide cathode with near-zero-strain for high-performance sodium-ion batteries.

Layered transition metal oxides (NaxTMO2) possess attractive features such as large specific capacity, high ionic conductivity, and a scalable synthesis process, making them a promising cathode candidate for sodium-ion batteries (SIBs). However, NaxTMO2 suffer from multiple phase transitions and Na+/vacancy ordering upon Na+ insertion/extraction, which is detrimental to their electrochemical performance. Herein, we developed a novel cathode material that exhibits an abnormal P2-type structure at a stoichiometric content of Na up to 1. The cathode material delivers a reversible capacity of 108 mA h g-1 at 0.2C and 97 mA h g-1 at 2C, retaining a capacity retention of 76.15% after 200 cycles within 2.0-4.3 V. In situ diffraction studies demonstrated that this material exhibits an absolute solid-solution reaction with a low volume change of 0.8% during cycling. This near-zero-strain characteristic enables a highly stabilized crystal structure for Na+ storage, contributing to a significant improvement in battery performance. Overall, this work presents a simple yet effective approach to realizing high Na content in P2-type layered oxides, offering new opportunities for high-performance SIB cathode materials.

An Intrinsic Stable Layered Oxide Cathode for Practical Sodium-Ion Battery: Solid Solution Reaction, Near-Zero-Strain and Marvelous Water Stability.

Non-aqueous solvents, in particular N,N-dimethylaniline (NMP), are widely applied for electrode fabrication since most sodium layered oxide cathode materials are readily damaged by water molecules. However, the expensive price and poisonousness of NMP unquestionably increase the cost of preparation and post-processing. Therefore, developing an intrinsically stable cathode material that can implement the water-soluble binder to fabricate an electrode is urgent. Herein, a stable nanosheet-like Mn-based cathode material is synthesized as a prototype to verify its practical applicability in sodium-ion batteries (SIBs). The as-prepared material displays excellent electrochemical performance and remarkable water stability, and it still maintains a satisfactory performance of 79.6% capacity retention after 500 cycles even after water treatment. The in situ X-ray diffraction (XRD) demonstrates that the synthesized material shows an absolute solid-solution reaction mechanism and near-zero-strain. Moreover, the electrochemical performance of the electrode fabricated with a water-soluble binder shows excellent long-cycling stability (67.9% capacity retention after 500 cycles). This work may offer new insights into the rational design of marvelous water stability cathode materials for practical SIBs.

Association of Web-Based Physical Education With Mental Health of College Students in Wuhan During the COVID-19 Outbreak: Cross-Sectional Survey Study.

BACKGROUND: The COVID-19 outbreak has affected people's health worldwide. For college students, web-based physical education is a challenge, as these course are normally offered outdoors. OBJECTIVE: The aim of this study was to use data from a web-based survey to evaluate the relationship between the mental health status of college students and their sports-related lifestyles. Problems related to web-based physical education were also examined. METHODS: A web-based survey was conducted by snowball sampling from May 8 to 11, 2020. Demographic data, mental health status, and sports-related lifestyles of college students in Wuhan as well as issues related to web-based physical education were collected. Mental health status was assessed by the Depression, Anxiety, and Stress Scale (DASS-21). RESULTS: The study included 1607 respondents from 267 cities. The average scores of the DASS-21 subscales (2.46 for depression, 1.48 for anxiety, and 2.59 for stress) were significantly lower in our study than in a previous study (P<.05). Lower DASS-21 scores were significantly correlated with regular exercise, maintaining exercise habits during the outbreak of COVID-19, exercising more than 1 to 2 times a week, exercise duration >1 hour, and >2000 pedometer steps (all P<.05). None of the three forms of web-based physical education was preferred by more than 50% of respondents. Frequent technical problems were confronted by 1087/1607 students (67.6%). Shape-up exercises (846/1607, 52.6%), a designed combination of exercises (710/1607, 44.2%), and Chinese kung fu (559/1607, 34.8%) were suggested sports for web-based physical education. CONCLUSIONS: Mental status was significantly correlated with regular exercise and sufficient exercise duration. Professional physical guidance is needed for college students in selected sports. Exercises not meeting students' preferences, frequent technical problems, and the distant interaction involved in web-based physical education were the main problems that should be solved in future.

[Expression and catalysis of glucokinase of Thermoanaerobacter tengcongensis at different temperatures].

According to analysis of proteomic profiling for Thermoanaerobacter tencongensis, TTE0090 could be a novel gene of glucokianse (GLK), though no GLK gene was annotated in the genomic data. With the methods of cloning and expression in vitro, the recombinant TTE0090 was successfully expressed and purified. The recombinant TTE0090 exhibited the catalysis of GLK, even at high temperatures. Detection of expression levels and catalysis of TTE0090 in vivo was furthermore carried out at different temperatures. The expression of TTE0090 was attenuated during the culture temperature elevated; however, the specific activity was positively correlated to temperature raised. This leads a possibility that the metabolic capacity of glycolysis in T. tencongensis is relatively constant at different temperatures. All the results herein demonstrate that TTE0090 is a novel gene of GLK. The studies on TTE0090 and its protein product, thus, may deepen our understanding of the adaptation mechanism of thermophilic bacteria living in harsh environment.

[Cloning, expression and characterization of the 6-phosphofructokinase from Thermoanaerobacter tengcongensis].

The enzyme of 6-phosphofructokinase (PFK) is a key element in glycolysis, widely distributed in most eukaryote and prokaryote. Although the gene TTE1816 from Thermoanaerobacter tengcongenisis was annotated as a PFK based upon genomic analysis, its catalytic properties have to be examined experimentally. The cells of T. tengcongenisis were cultured at optimal temperature followed by the separation of the bacterial proteins with two-dimensional electrophoresis (2-DE). These 2-DE spots located around the theoretical values of pI and MW for TTE1816 were picked up and identified by mass spectrometry, suggesting that TTE1816 indeed expressed at such high temperature. Furthermore, TTE1816 was cloned into an expression vector and expressed soluble protein in E. coli BL-21 strain. The kinetic data revealed that the recombinant TTE1816 exhibited the catalysis to phosphorylate fructose-6-phosphate (F-6-P). Not only converting F-6-P to F-1,6-BP, does TTE1816 also catalyze the phosphorylation of glucose, fructose, mannose and glucose-6-phosphate(G-6-P) with optimal temperature at 60 degrees C . Interestingly, TTE1816 is capable to catalyze the reverse reaction as a bisphosphatase for dephosphorylation of F-1,6-BP under the reaction conditions with high concentrations of enzyme as well as substrates. The data reported herein demonstrate that a new member of PFK family has been identified in T. tengcongenisis.

[Study on the membrane proteins of Alkalimonas amylolytica N10 expressed at different pH environment].

The research on the membrane proteins expressed in alkaliphiles at different pH media will be benefit to understand the molecular mechanisms how they survive from such harsh alkaline environment. A preliminary investigation to the differential membrane proteomes from Alkalimonas amylolytica N10 (N10), a novel alkaliphilic bacterium, is reported herein. Upon the growth curves of N10 at different pH environment, three pH media, 8.4, 9.4 and 10.4, respectively, were employed to culture N10 followed by membrane preparation using ultracentrifuge and membrane proteins separation by 8% - 20% gradient SDS-PAGE. With carefully image analysis and statistical calculation, 7 stained bands were confirmed the alterations of relative optimal intensities corresponding with pH environment. Furthermore these bands were digested in-gel by trypsin and delivered to LC-MS/MS for protein identification. Twelve proteins were verified, of which four were reported involvement of the regulation of pH homeostasis in cytoplasm of alkaliphiles, and the others were originally found their protein expression responding to the environment with different pH values.

[Dynamic analysis of the heat shock protein 60 and its gene expression in Thermoanaerobacter tengcongensis induced by temperature increase].

Heat shock protein 60 (HSP60) is one of the important chaperonins, which can assist proper protein folding and configuration,and can prevent denaturation and degradation of proteins as well. It was found that HSP60 in Thermoanaerobacter tengcongensis (T. tengcongensis) was typically temperature-dependent with the highest protein expression at 80 degrees C. To understand the molecular mechanisms of thermophiles in their responding to heat stress, further investigation was conducted to examine the dynamic expression of HSP60 gene induced by higher temperature. The T. tengcongensis cells cultured at optimal temperature (75 degrees C) were transferred to 80 degrees C followed by taking the aliquots at different time intervals. To monitor the expression levels of HSP60 mRNA and protein, these bacterial gene products were analyzed by two-dimensional electrophoresis, MALDI-TOF, HPLC-MS/MS, Western blot and quantitative PCR. The experimental data were calculated statistically and quantitatively, which indicate that the HSP60 protein increases steadily and significantly within 4h period after temperature raised, but its mRNA level is shown as a peak shape change within 1h. Obviously, the expression response of HSP60 protein to heat stress is significantly slower than that of its mRNA expression. Additionally, the expression extent of HSP60 mRNA and protein induced by raised-temperature is very different. In E. coli strains, the expression of HSP60 is usually regulated by the sigma32 factor, which disassociates with DnaK immediately when the environmental temperature elevated. Since the genome of T. tengcongensis contains two sigma32 genes, thus, it is likely that both bacteria share the similar mechanisms which regulate HSP60 transcription responding to the changes of temperature. Interestingly, the mRNA of HSP60 drops down about 70% within 30m responding to heat shock, but goes to the increased expression after then. Although this phenomenon is hard to explain based upon the current theory, it is plausible that the transcription in T. tengcongensis is temporally inhibited due to the culture temperature sharply raised.