Microstructure and mechanical properties of carbon graphite composites reinforced by carbon nanofibers

Chen Yixing,Tu Chuanjun,Liu Yanli,Liu Ping,Gong Pei,Wu Guangning,Huang Xia,Chen Jian,Liu Tianhua,Jiang Jizhou 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Renewed interest in the reinforced carbon graphite composites has intrigued the community in the advanced materials fields. In this work, we present a simple carbon nanofibers reinforced carbon graphite composites synthetic method by incorporating mixture of coal tar pitch, synthetic graphite, pitch coke and the dispersion liquid of carbon nanofibers via liquid-phase mixing process. The impact of carbon nanofiber utilization on the microstructures and mechanical properties of carbon graphite composites are studied systematically. The covalent surface modification of carbon nanofibers effectively improves its microstructure and thereby promotes the carbon graphite composites’ dispersion behavior. We propose that a small amount of carbon nanofibers could promote the carbonization process of carbon graphite composites, facilitating the densification of carbon graphite composites and reducing the undesired open porosity. The amount of 0.7 wt % of carbon nanofiber concentration allows the enhancement of bend and compressive strength of carbon graphite composites up to 36.50 MPa and 60.46 MPa, increased by 167.9% and 146.9% compared with the pure carbon graphite composite, respectively. Our findings can be rationalized due to the improvement in the mechanical strength of carbon graphite composites could be attributed due to pull-out of carbon nanofibers from the matrix and bridging effect across the crack pores within the matrix.

MAPK4 silencing in gastric cancer drives liver metastasis by positive feedback between cancer cells and macrophages

Li Shuang,Guo Dongyang,Sun Qiang,Zhang Lu,Cui Yun,Liu Min,Ma Xixi,Liu Yiman,Cui Wenyu,Sun Leimin,Teng Lisong,Wang Liangjing,Lin Aifu,Liu Wei,Zhuo Wei,Zhou Tianhua 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Liver metastasis is a major cause of death in gastric cancer patients, but the underlying mechanisms are poorly understood. Through a combination of in vivo screening and transcriptome profiling followed by quantitative RT-PCR and tissue array analyses, we found that mitogen-activated protein kinase 4 (MAPK4) downregulation in gastric cancer tissues from patients is significantly associated with liver metastasis and poor prognosis. The knockdown of MAPK4 in gastric cancer cells promotes liver metastasis in orthotopic mouse models. MAPK4 depletion in gastric cancer cells induces the secretion of macrophage migration inhibitory factor (MIF) to polarize tumor-associated macrophages (TAMs) in orthotopic xenograft tumors. Moreover, TAMs activate epithelial–mesenchymal transition of gastric cancer cells to suppress MAPK4 expression, which further increases MIF secretion to polarize TAMs. Taken together, our results suggest a previously undescribed positive feedback loop between cancer cells and macrophages mediated by MAPK4 silencing that facilitates gastric cancer liver metastasis.

Three-dimensionally Hierarchical Bi2WO6 Architectures with Enhanced Photocatalytic Activity

Tianhua Chen,Hongbing Lu,Jinniu Zhang,Jianzhi Gao,Feng Yin,Zhibo Yang,Qianru Liu,Xuewei Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.12

Three-dimensionally hierarchical Bi2WO6 architectures have been produced via a facile and economical hydrothermal method without any template or surfactant. This architecture with flower-like morphology is assembled by numbers of intercrossed nanosheets. Moreover, different Bi2WO6 nanostructures including multilayered disks and irregular nanoplates can also be produced by simply adjusting the pH value of the precursor solution. Importantly, this kind of hierarchically structured Bi2WO6 architecture exhibits a much better photocatalytic activity in the photodegradation of rhodamine B than that of conventional Bi2WO6 multilayered disks and nanoplates. This enhanced photocatalytic performance is mainly attributed to the large specific surface areas, special structural features and high capability of absorbed oxygen species. The present work offers an effective approach for the further improvement of photocatalytic activity by designing a desirable micro/nanoarchitecture.

Paeonol accelerates skin wound healing by regulating macrophage polarization and inflammation in diabetic rats

Zuyang Zhang,Tianhua Chen,Wei Liu,Jiepeng Xiong,Liangdong Jiang,Mingjiang Liu 대한약리학회 2023 The Korean Journal of Physiology & Pharmacology Vol.27 No.5

Diabetic ulcer is usually seen in people with uncontrolled blood sugar. Reportedly, many factors such as impaired glucose metabolism, and macrovascular and microvascular diseases caused angiogenesis disorders and delayed the healing of diabetic ulcers, thus affecting the body's metabolism, nutrition, and immune function. This study aimed to explore the effect of paeonol on skin wound healing in diabetic rats and the related mechanism. A rat model of diabetic ulcer was established. High glucose-treated mouse skin fibroblasts were co-cultured with M1 or M2- polarized macrophages treated with or without paeonol. H&E and Masson staining were used to reveal inflammatory cell infiltration and collagen deposition, respectively. Immunohistochemistry visualized the expression of Ki67, CD31, and vascular endothelial growth factor (VEGF). Western blot was used to detect interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-4, IL-10, CD31, VEGFA, and collagen I/III. The expression of iNOS and arginase 1 was revealed by immunofluorescence staining. Paeonol treatment augmented collagen deposition and the expression of Ki67, CD31, VEGF, and macrophage M2 polarization markers (IL-4 and IL-10) and reduced wound area, inflammatory cell infiltration, and macrophage M1 polarization markers (IL-1β and TNF-α) in the ulcerated area. In vitro, paeonol treatment promoted M2-polarization and repressed M1-polarization in macrophages, thereby improving the repair of cell damage induced by high glucose. Paeonol accelerates the healing of diabetic ulcers by promoting M2 macrophage polarization and inhibiting M1 macrophage polarization.

Compressive behavior of built-up open–section columns consisting of four cold-formed steel channels

Shaofeng Nie,Cunqing Zhao,Zhe Liu,Yong Han,Tianhua Zhou,Hanheng Wu 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.45 No.6

Compression experiments were conducted to investigate the compressive behavior of built-up open-section columns consisting of four cold-formed steel channels (BOCCFSs) of different lengths, thicknesses, and cross-section sizes (OB90 and OB140). The load-displacement curves, failure modes, and maximum compression strength values were analyzed in detail. The tests showed that the failure modes of the OB90 specimens transformed from a large deformation concentration induced by local buckling to flexural buckling with the increase in the slenderness ratio. The failure modes of all OB140 specimens were deformation concentration, except for one long specimen, whose failure mode was flexural buckling. When the slenderness ratios of the specimens were less than 55, the failure modes were controlled by local buckling. Finite element models were built using ABAQUS software and validated to further analyze the mechanical behavior of the BOCCFSs. A parametric study was conducted and used to explore a wide design space. The numerical analysis results showed that when the screw spacing was between 150 mm and 450 mm, the difference in the maximum compression strength values of the specimens was less than 4%. The applicability and effectiveness of the design methods in Chinese GB50018-2002 and AISI-S100-2016 for calculating the compression strength values of the BOCCFSs were evaluated. The prediction methods based on the assumptions produced predictions of the strength that were between 33% to 10% conservative as compared to the tests and the finite element analysis.

Optimized Thermoelectric Properties of AgSbTe2 through Adjustment of Fabrication Parameters

Jian Zhang,Xiaoying Qin,Di Li,송천준,Yongfei Liu,Hongxing Xin,Tianhua Zou,Yuanyue Li 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.1

AgSbTe2 bulk sample is obtained by hot-pressing under different fabricationparameters, and their thermoelectric properties are investigated in thetemperature range of 300 - 550 K. The highest ZT = 0.86 is achieved at475 K for the sample hot-pressed at 423 K and 500MPa due to the lowerthermal conductivity and higher power factor. The results indicate that theoptimized thermoelectric properties can be obtained for AgSbTe2 compoundat the sintering temperature of 423 K under the pressure of 500 MPa.