The extensively used latex mixing approach to prepare graphene can improve the graphene dispersion but meets some challenges in the preparation of high content carbon black filled rubber system like a rubber tire. Owing to the high melt viscosity of the rubber/graphene masterbatch, the dispersion of carbon black is not perfect during twin-roll mixing and some aggregates will be formed. Here we proposed a wet compounding process, combined with ultrasonically assisted latex mixing, named as the WCL method to prepare reduced graphene oxide/carbon black/natural rubber (rGO/CB/NR) composites. The morphological observations confirmed that both graphene and carbon black can be evenly dispersed in the rubber composites. The incorporation of rGO also improves the hardness, thermal conductivity and anti-aging properties of the composites. The rGO/CB/NR composites prepared by the WCL method possess better mechanical properties compared to conventional latex mixing. The entanglement-bound rubber tube model was utilised to understand the reinforcing mechanism.
The transmembrane glycoprotein embigin (EMB) belongs to the immunoglobulin superfamily (IgSF) and a number of IgSF members have been identified as biomarkers for cancer progression. In this study, we show that embigin is transcriptionally regulated by Homeobox C8 (HOXC8) in breast cancer cells and embigin expression suppresses breast tumorigenesis. With aid of Western blot, luciferase reporter gene assay and chromatin immunoprecipitation, we reveal that HOXC8 binds to the EMB promoter at the region of nucleotides −2303 to −2315 and acts as a transcription inhibitor to suppress embigin expression. Depletion of embigin leads to increase in proliferation, anchorage-independent growth and migration of breast cancer cells, and the inhibitory effects mediated by HOXC8 knockdown on breast tumorigenesis can be largely rescued by depletion of embigin expression in breast cancer cells, suggesting that HOXC8 regulates breast tumorigenesis, at least partly, through regulating embigin expression. Moreover, we show that loss of embigin promotes proliferation, anchorage-independent growth, and migration ability of normal mammary epithelial MCF10A cells. The analyses of publically available human breast tumor microarray gene expression database show that low embigin levels correlate with short survival of breast tumor patients, particularly with basal-like tumor patients, and embigin expression is low specifically in patients with basal-like, ER-/HER2- tumors. Taken together, our study demonstrates that low/loss of embigin plays an important role in the progression of breast tumors.
The reduced graphene oxide (rGO) modified natural rubber composite (NR) filled with high contents of silica was prepared by a wet compounding and latex mixing process using a novel interface modifier cystamine dihydrochloride (CDHC) with coagulation ability. CDHC acts as a coagulation agent through electrostatic interaction with rGO, SiO2, and latex rubber particles during the latex-based preparation process, while in the obtained silica/graphene/natural rubber composites, CDHC acts as an interface modifier. Compared with the composites prepared by the conventional mechanical mixing method, the dispersion of both rGO and SiO2 in the composites made by a wet compounding and latex mixing process is improved. As a result, the obtained silica/graphene/natural rubber composite prepared by this new method has good comprehensive properties. A Dynamic Mechanical Test suggests that the tan δ values of the composites at 60 oC decrease, indicating a low rolling resistance with increasing the graphene content at a low strain, but it increases at a higher strain. This unique feature for this material provides an advantage in the rubber tire application.
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