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6-Gingerol, a natural component of ginger, has been widely reported to possess antiinflammatory and antitumorigenic activities. Despite its potential efficacy against cancer, the anti-tumor mechanisms of 6-gingerol are complicated and remain sketchy. In the present study, we aimed to investigate the anti-tumor effects of 6-gingerol on colon cancer cells. Our results revealed that 6-gingerol treatment significantly reduced the cell viability of human colon cancer cell, LoVo, in a dose-dependent manner. Further flow cytometric analysis showed that 6-gingerol induced significant G2/M phase arrest and had slight influence on sub-G1 phase in LoVo cells. Therefore, levels of cyclins, cyclin-dependent kinases (CDKs), and their regulatory proteins involved in S-G2/M transition were investigated. Our findings revealed that levels of cyclin A, cyclin B1, and CDK1 were diminished; in contrast, levels of the negative cell cycle regulators p27Kip1 and p21Cip1 were increased in response to 6-gingerol treatment. In addition, 6-gingerol treatment elevated intracellular reactive oxygen species (ROS) and phosphorylation level of p53. These findings indicate that exposure of 6-gingerol may induce intracellular ROS and upregulate p53, p27Kip1, and p21Cip1 levels leading to consequent decrease of CDK1, cyclin A, and cyclin B1 as result of cell cycle arrest in LoVo cells. It would be suggested that 6-gingerol should be beneficial to treatment of colon cancer.

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Crack healing in poly(methyl methacrylate) (PMMA) by methanol treatment at 40°C–60°C has been investigated. It is found that the methanol treatment reduces the glass transition temperature in PMMA. Crack healing only occurs at an operating temperature higher than the effective glass transition temperature. There are two distinctive stages for crack healing based on the recovery of mechanical strength. The first stage corresponds to the progressive healing due to wetting, which has a constant crack closure rate at a given temperature. Immediately following the first stage, the second stage corresponding to diffusion enhances the quality of healing behavior. The surface morphologies obtained during healing and after fracture tests confirm these two stages. By comparing the fracture stress with the fractography, the fracture surface for stage I of crack healing is coplanar to the original crack surface. On the other hand, the original crack surface is destroyed in stage II of crack healing. It occurs in the region incorporating the original healed surface and appears to be like the Virgin fracture surface. It is also found that the tensile fracture stress of PMMA treated by methanol can recover to that of the virgin material. In addition, it is interesting to find that after sustained methanol treatment, the “snake bone” phenomenon on the fracture surface emerges.

No abstract

Phenol-formaldehyde resins synthesized using different formaldehyde-to-phenol molar ratios (F/P ratios) were used as precursors for production of activated carbons from steam activation and KOH etching. The base-catalyzed method was employed in the synthesis with the F/P ratio ranging within 1-4. It was found that the resin yield decreased with the F/P ratio, while the fixed carbon content of the resins increased with the ratio. Solid-state 13 C NMR analysis showed that increasing the F/P ratio resulted in an increased degree in aromatic ring substitution, which would lead to a promoted cross-linking upon heat treatment and thus to a higher carbon yield. The specific porosity of the carbons from steam activation was shown to decrease with the F/P ratio. The difference in the porosity has been ascribed to the different numbers of original pores embedded in the carbons prior to activation. The F/P ratio did not show obvious influence on the specific porosity development for carbon production using KOH etching. The yield for producing high-porosity carbons from KOH etching was higher than that from steam activation. For both of the activation methods, a F/P ratio of unity is recommended for creating high overall carbon porosity based on per unit mass of phenol used.

The effects of spin friction pressure and time on the friction welding between parts of the same material and different materials are discussed. The heat‐affected zone is divided into three regions: the plasticized region (Zpl), the partly plasticized region (Zpd), and the undeformed region (Zud). The tensile fracture morphology has three sections: the non‐plasticized central section (Fud), the plasticized peripheral section (Fpl), and the partly plasticized section between Fud and Fpl (Fpd). Friction pressure (spinning timing): 0.784 Mpa (6 seconds), 0.981 MPa (8 seconds and 10 seconds) in PMMA‐PMMA welding, 0.588 Mpa (10 seconds) in PVC‐PVC welding, and 15.7 MPa (15 seconds) in PMMA‐PVC welding attains better bonding strength, because these parts have larger Fpd and Fpl regions, which have no Fud in the central part.

No abstract