Search

The theory of tire wear computation is researched, and steady state transfer analysis and steady state rolling slippage are analyzed and deduced; the uniform wear rate of discrete node on the tire tread pattern is induced based on adhesive wear mechanism. Tire body model and tread pattern model are established by using Neo-Hooken constitutive model and linear elastic model, and the whole tire model is formed. Tire wear simulation analysis is preceded with combination of Abaqus Arbitary Lagrangian and Eulerian (ALE) method and the user subroutine programmed according to tire wear computation model. Tire wear of different mileage under free rolling state, tire wear under breaking condition and driving condition are compared, and slip angle, load and tire pressure’s impact on tire wear are analyzed.

Here, a novel anticancer gene therapy with a bacterial tRNase gene, colicin D or virulence associated protein C (VapC), is suggested using biodegradable polymeric nanoparticles, such as poly(β‐amino esters) (PBAEs) as carriers. These genes are meticulously selected, aiming at inhibiting translation in the recipients by hydrolyzing specific tRNA species. In terms of nanoparticles, out of 9 PBAE formulations, a leading polymer, (polyethylene oxide)4‐bis‐amine end‐capped poly(1,4‐butanediol diacrylate‐co‐5‐amino‐1‐pentanol) (B4S5E5), is identified that displays higher gene delivery efficacy to cancer cells compared with the leading commercial reagent Lipofectamine 2000. Interestingly, the B4S5E5 PBAE nanoparticles complexed with colicin D or VapC plasmid DNA induce significant toxicity highly specific to cancer cells by triggering apoptosis. In contrast, the PBAE nanoparticles do not induce these cytotoxic effects in noncancerous cells. In a mouse melanoma model of grafted murine B16‐F10 cells, it is demonstrated that treatment with PBAE nanoparticles complexed with these tRNase genes significantly reduces tumor growth rate and delays tumor relapse. Moreover, increased stability of PBAE by PEGylation further enhances the therapeutic effect of tRNase gene treatment and improves survival of animals. This study highlights a nonviral gene therapy that is highly promising for the treatment of cancer. A novel anticancer gene therapy using bacterial tRNase genes and biodegradable poly(β‐amino esters) (PBAE) nanoparticlesis suggested. tRNase gene therapy with PBAE nanoparticles induces cytotoxicity specific to cancer cells. The tRNase–based gene therapy suppresses tumor growth and relapse in a mouse melanoma tumor model. PEGylation of PBAE formulation further increases the antitumoral effect of bacterial tRNase gene therapy.

Redox enzymes are widely used as powerful biocatalysts owing to their high selectivity and sustainability. Since most of the enzymatic reactions require the expensive coenzyme (the reduced form of nicotinamide adenine dinucleotide, NADH) in a stoichiometric amount, efficient NADH regeneration is essential for various biocatalytic syntheses. Even though an electroenzymatic recycling method has many advantages, it requires low-molecular-weight redox mediators to transfer electrons from electrodes to an enzymes' active site, which are generally toxic and make it difficult to purify products after the reaction. In the present study, we have conjugated a mediator to enzyme catalyst to solve the problem of the electroenzymatic NADH regeneration. Mediators bound to enzymes can be separated from the reaction medium and then reused readily. Moreover, the conjugation can promote a faster electron transfer between mediators and enzymes. For the conjugation, a viologen with a carboxyl group, ethyl carboxyethyl viologen (ECV) was synthesized and covalently linked to diaphorase (DI) using a cross-linker. Cyclic voltammetry showed that the ECV conjugated to DI displayed electrochemical behavior similar to free ECV. In marked contrast to native DI, the DI-ECV conjugate reduced NAD+to NADH without any mediator, and this bioelectrocatalyst regenerated NADH successfully for enzymatic lactate synthesis.