Background: Multidrug resistance (MDR) presents a problem in cancer chemotherapy, and developing new agents to overcome MDR is important. This study intends to investigate the reversal effect of β-elemene on MDR in human breast carcinoma MCF-7 and doxorubicin-resistant MCF-7 cells. Methods: MTT cytotoxicity assays, flow cytometry, and Western blot analysis were performed to investigate the antiproliferative effects of the combination of anticancer drugs with β-elemene, to study the reversal of drug resistance, and to examine the inhibitory effects on protein expression. Results: The results showed that β-elemene (30 µmol/l) had a strong potency to increase the cytotoxicity of doxorubicin to MCF-7/DOX cells, with a reversal fold of 6.38. In addition, the mechanisms of β-elemene in reversing P-glycoprotein (P-gp)-mediated MDR demonstrated that β-elemene significantly increases the intracellular accumulations of doxorubicin and Rh123 via inhibition of the P-gp transport function in MCF-7/DOX cells. Flow cytometry and Western blot analyses revealed that β-elemene could inhibit the expression of P-gp, while it had little effect on the expression of MRP1 protein. In addition, β-elemene had little inhibitory effect on the intracellular GSH levels and GST activities in MCF-7/DOX cells. Conclusions: β-Elemene might represent a promising agent for overcoming MDR in cancer therapy.

The energy efficiency for electric vehicle battery is affected by many factors. Through the definition of energy efficiency we find the relationship between energy efficiency, voltage efficiency and coulomb efficiency. The factors such as current, internal resistance, SOC and temperature which affect coulomb efficiency and voltage efficiency, will affect energy efficiency as well. An equation is given to show how internal resistance and current influence the energy efficiency. The relationship between these factors and energy efficiency was analyzed through theory and experimental data. This will show ways to increase battery energy efficiency and improve the battery performance.

The amphibious robot is so attractive and challenging for its broad application and its complex working environment. It should walk on rough ground, maneuver underwater and pass through transitional terrain such as sand and mud, simultaneously. To tackle with such a complex task, a novel amphibious robot (AmphiHex-I) with transformable leg-flipper composite propulsion is proposed and developed. This paper presents the detailed structure design of the transformable leg-flipper propulsion mechanism and its drive module, which enables the amphibious robot passing through the terrain, water and transitional zone between them. A preliminary theoretical analysis is conducted to study the interaction between the elliptic leg and transitional environment such as granular medium. An orthogonal experiment is designed to study the leg locomotion in the sandy and muddy terrain with different water content. Finally, basic propulsion experiments of AmphiHex-I are launched, which verified the locomotion capability on land and underwater is achieved by the transformable leg-flipper mechanism.

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