A simple electrospinning strategy to achieve the uniform distribution of ultra‑fine CoP nanocrystals on carbon nanofibers for efficient lithium storage

Qinghua Wang,Wei Wang,Junlin Huang,Hong Yin,Yucan Zhu,Haitao Wang,Minjie Zhou,Binhong He,Zhaohui Hou,Wenyuan Xu 한국탄소학회 2023 Carbon Letters Vol.33 No.1

Transition-metal phosphides (TMPs), a promising anode material for lithium-ion batteries (LIBs), are limited in application because of its serious volume effect in the cycle. In this work, a simple electrospinning strategy was proposed to restrict the grain size of CoP nanocrystals by nano-confined effect of carbon nanofibers with ligands. The addition of ligands not only could realize the uniform dispersion of CoP nanocrystals, but also strengthen the bond between the metals and carbon nanofibers. As a result, the CoP/CNF composite exhibits excellent lithium storage performance, and its reversible specific capacity could reach 1016.4 mAh g? 1 after 200 cycles at a current density of 200 mA g? 1. The research is anticipated to provide a new idea for the preparation of anode materials for lithium ion batteries.

Synthesis of S-adenosyl-L-methionine in Escherichia coli

Xiao-Nan Wei,Minjie Cao,Jian Li,Huan Li,Yi Song,Cuihong Du 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.6

S-adenosyl-L-methionine (SAM) is an importantphysiological metabolite in vivo and may be useful inmedicines. SAM is produced from L-methionine and ATPcatalyzed by S-adenosyl-L-methionine synthetase (SAMS)in vivo. In this study, the gene encoding SAMS was clonedand a genetically engineered Escherichia coli (E. coli)BL21(pET-28a-SAMS) was constructed. The recombinantSAMS with a molecular mass of approximately 46 kDawas expressed by inducing the engineered E. coli usingisopropyl-β-D-1-thiogalactopyranoside (IPTG) as an inducer. To produce SAM using a low-cost, nontoxic and highperformanceexpression system, lactose was used as asubstitute for IPTG to induce BL21(pET-28a-SAMS). Byoptimizing the expression conditions, the concentration ofSAM produced by the engineered E. coli was 48 mg/L in theculture medium supernatant. To increase the concentrationof SAM produced, a coupled system was constructedconsisting of E. coli BL21(pET-28a-SAMS) and Saccharomycescerevisiae (S. cerevisiae) JM-310. In this coupled system,ATP generated from S. cerevisiae was provided to E. colifor producing a higher concentration of SAM. The SAMconcentration in the coupled system reached 1.7 g/L. SAMwas purified by a weak acid cationic exchange resin D113,and a simple and economical purification procedure forSAM isolation was achieved. SAM was confirmed byHigh Performance Liquid Chromatography-tandem MassSpectrometry analysis. Our study provides a feasible andconvenient approach to produce SAM.

A new analytical ICCE and force prediction model for wide-row machining of free-form surface

Minglong Guo,Zhaocheng Wei,Jia Wang,Minjie Wang,Xiaoyu Wang,Shengxian Liu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1

Cutting force is the most intuitive reflection of various influencing factors in the milling process, which is important for improving machining quality and efficiency. For the widerow milling with flat-end mill of free-form surface, an analytical in-cut cutting edge (ICCE) algorithm is studied in detail, and overall cutting force model is further constructed. The cutter location points along tool path are discretized into small oblique planes. Taking the oblique plane machining as the new object, the relative position of flat-end mill and workpiece in five-axis machining is defined parametrically. By constructing a semi-enclosed space in which the cutting edge participates in cutting, the ICCE is directly obtained. By analyzing the cutting force of oblique plane, the cutting force model of free-form surface can be established by spatial coordinate transformation. The simulation and experiment have demonstrated the correctness and effectiveness of the proposed ICCE algorithm and force prediction model.

Modeling of dynamic recrystallization in white layer in dry hard cutting by finite element—cellular automaton method

Duan Chunzheng,Zhang Fangyuan,Qin Siwei,Sun Wei,Wang Minjie 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9

White layer formed in hard cutting process has great influence on surface quality of the workpiece, simulation of the white layer has great significance. Dynamic recrystallization critical temperature model is derived to calculate the critical temperature of the dynamic recrystallization in the white layer. A finite element model was developed to simulate the hard cutting process based on the JohnsonCook constitutive equation. The dynamic recrystallization critical temperature was derived based on the true stress-strain curves obtained by the split Hopkinson pressure bar experiments. The cellular automaton model which aims to simulate the white layer grains formed by the dynamic recrystallization process in hard cutting is established. The temperature and strain data extracted from the finite element model are used in the cellular automaton model. The contrast between the simulation and experimental results demonstrates that the cellular automaton model can simulate the dynamic recrystallization process in the white layer accurately. The dynamic recrystallization processes in the white layer under different cutting speed and flank wear are simulated based on the finite element - cellular automaton model. The results show that the dynamic recrystallization grain size of the white layer decreases with the increase in cutting speed and tool wear.

Preparation of self‑supporting Co3S4/ S‑rGO film catalyst for efficient oxygen evolution reaction

Liang Chen,Liying Hu,Chenxi Xu,Lanyun Yang,Wei Wang,Junlin Huang,Minjie Zhou,Zhaohui Hou 한국탄소학회 2023 Carbon Letters Vol.33 No.7

Exploring cheap and efficient oxygen evolution reaction (OER) catalysts is extremely vital for the commercial application of advanced energy storage and conversion systems. Herein, a self-supporting Co3S4/ S-doped reduced graphene oxide ( Co3S4/S-rGO) film catalyst is successfully prepared by a blade coating coupled with high-temperature annealing strategy, and its morphology, structure and composition are measured and analyzed. It is substantiated that the as-synthesized Co3S4/ S-rGO film possesses unique self-supporting structure, and is composed of uniformly dispersed Co3S4 nanoparticles and highly conductive S-rGO, which benefit the exposure of catalytic sites and electron transfer. By reason of the synergistic effect of the two individual components, the self-supporting Co3S4/ S-rGO film catalyst displays outstanding catalytic performance towards OER. As a consequence, the Co3S4/ S-rGO film catalyst delivers an overpotential of 341 mV at 10 mA cm-2, and the current attenuation rate is only 2.6% after continuous operation for 4 h, verifying excellent catalytic activity and durability. Clearly, our results offers a good example for the construction of high-performance self-supporting carbon-based composite film catalysts for critical electrocatalytic reactions.

Nuciferine modulates the gut microbiota and prevents obesity in high-fat diet-fed rats

Wang Yueping,Yao Weifan,Li Bo,Qian Shiyun,Wei Binbin,Gong Shiqiang,Wang Jing,Liu Mingyan,Wei Minjie 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

Gut microbiota dysbiosis has a significant role in the pathogenesis of metabolic diseases, including obesity. Nuciferine (NUC) is a main bioactive component in the lotus leaf that has been used as food in China since ancient times. Here, we examined whether the anti-obesity effects of NUC are related to modulations in the gut microbiota. Using an obese rat model fed a HFD for 8 weeks, we show that NUC supplementation of HFD rats prevents weight gain, reduces fat accumulation, and ameliorates lipid metabolic disorders. Furthermore, 16S rRNA gene sequencing of the fecal microbiota suggested that NUC changed the diversity and composition of the gut microbiota in HFD-fed rats. In particular, NUC decreased the ratio of the phyla Firmicutes/Bacteroidetes, the relative abundance of the LPS-producing genus Desulfovibrio and bacteria involved in lipid metabolism, whereas it increased the relative abundance of SCFA-producing bacteria in HFD-fed rats. Predicted functional analysis of microbial communities showed that NUC modified genes involved in LPS biosynthesis and lipid metabolism. In addition, serum metabolomics analysis revealed that NUC effectively improved HFD-induced disorders of endogenous metabolism, especially lipid metabolism. Notably, NUC promoted SCFA production and enhanced intestinal integrity, leading to lower blood endotoxemia to reduce inflammation in HFD-fed rats. Together, the anti-obesity effects of NUC may be related to modulations in the composition and potential function of gut microbiota, improvement in intestinal barrier integrity and prevention of chronic low-grade inflammation. This research may provide support for the application of NUC in the prevention and treatment of obesity.

Constructing all-in-one graphene-based supercapacitors for electrochemical energy storage via interface integration strategy

Zhu Yucan,Peng Long,Chen Song,Feng Yuchao,Xia Jianxing,Wang Wei,Chen Liang,Yin Hong,Zhou Minjie,Hou Zhaohui 한국탄소학회 2023 Carbon Letters Vol.33 No.3

With the rapid development of flexible wearable electronic products, flexible all graphene-based supercapacitors (FGSCs) with reduced graphene oxide rGO//graphene oxide (GO)//rGO structure have attracted substantial attention due to their unique structures and energy storage mechanism. However, restricted by design idea and preparation technology, improvement of capacitance performance for the FGSCs is not obvious recently. Herein, we demonstrate that an interface integration strategy of constructing the high-performance FGSCs with compact structure. Hydroquinone (HQ)-modified rGO (HQ-rGO) films (electrode materials) and sulfuric acid-intercalated GO films (electrolyte/separator) are assembled into the FGSCs utilizing hydrogen bonding and capillary contractility. The HQ further improves the electrochemical capacitance of electrode materials. The synergistic effect of the hydrogen bonding and capillary contractility guarantees compact and stable structure of the device. The resulting FGSCs exhibit an excellent areal capacitance of 804.6 mF cm−2 (@2 mA cm−2) and 441 mF cm−2 (@30 mA cm−2), and their highest energy and power densities can achieve 109.5 μWh cm−2 and 21,060 μW cm−2, respectively. These performances are superior to other all-in-one graphene-based SCs reported. Therefore, the construction technology of the FGSCs is a promising for developing all graphene-based SCs with high-performance.

Co2+-coordination-assisted enhancement of mechanical and iodynamic properties of 3D graphene-based double network hydrogels for all-solid-state supercapacitors

He Binhong,Wen Shuntao,Wen Zhiming,Liang Yan,Yang Qianxi,Zhou Minjie,Wang Wei,Wang Guo-Xiang 한국탄소학회 2024 Carbon Letters Vol.34 No.3

This paper reports an enhanced strategy for improving the mechanical flexibility and ionic kinetic properties of a double network hydrogel based on Co2+-coordination assistance. The modified double-network hydrogel was obtained by using acrylic acid and N, N-dimethylacrylamide as monomers, adding cross-linking agents and 3D nitrogen-doped graphenes. The tensile fracture rate of the modified hydrogel was 1925% and its tensile strength was 1696 kPa. In addition, the hydrogel exhibited excellent ionic dynamics, and its application to an all-solid-state supercapacitor was able to achieve a specific capacitance of up to 182.8 F g−1. The supercapacitor exhibited an energy density of 34.2 Wh kg−1, even when operating at a power density of 5 kW kg−1, highlighting its significant potential for practical applications.

Silencing of Fanconi Anemia Complementation Group F Exhibits Potent Chemosensitization of Mitomycin C Activity in Breast Cancer Cells

Jiankun Yu,Lin Zhao,Yanlin Li,Na Li,Miao He,Xuefeng Bai,Zhaojin Yu,Zhihong Zheng,Xiaoyi Mi,En-Hua Wang,Minjie Wei 한국유방암학회 2013 Journal of breast cancer Vol.16 No.3

Purpose: Fanconi anemia complementation group F (FANCF) is a key factor to maintaining the function of Fanconi anaemia/BRCA (FA/BRCA) pathway, a DNA-damage response pathway. However,the functional role of FANCF in breast cancer has not been elucidated. In the present study, we evaluated the chemosensitization effect of FANCF in breast cancer cells. Methods: We performed specific knockdown of the endogenous FANCF in breast cancer cells by transfecting the cells with an FANCF short hairpin RNA (shRNA) vector. Cell viability was measured with a Cell Counting Kit-8, and DNA damage was assessed with the alkaline comet assay. The apoptosis, cell cycle, and drug accumulation were measured by flow cytometric analysis. Protein expression levels were determined by Western blot analysis, using specific antibodies. Results: The analyses of two breast cancer cell lines (MCF-7 and MDA-MB-435S) demonstrated that the FANCF shRNA could effectively block the FA/BRCA pathway through the inhibition of Fanconi anemia complementation group D2ubiquitination. Moreover, FANCF silencing potentiated the sensitivity of cells to mitomycin C (MMC), where combined FANCF shRNA/MMC treatment inhibited cell proliferation, induced Sphase arrest, apoptosis, and DNA fragmentation, and reduced the mitochondrial membrane potential, compared with MMC treatment alone. Conclusion: Taken together, this study demonstrates that the inhibition of FANCF by its shRNA leads to a synergistic enhancement of MMC cytotoxicity in breast cancer cells. These results suggest that the inhibition of the FA/BRCA pathway is a useful adjunct to cytotoxic chemotherapy for the treatment of breast cancer.