The protective effect of PL 1-3 on D-galactose-induced aging mice

The aging population has become an issue that cannot be ignored, and research on aging is receiving increasing attention. PL 1-3 possesses diverse pharmacological properties including anti-oxidative stress, inhibits inflammatory responses and anti-apoptosis. This study showed that PL 1-3 could protect mice, especially the brain, against the aging caused by D-galactose (D-gal). D-gal could cause oxidative stress, inflammation, apoptosis and tissue pathological injury and so on in aging mice. The treatment of PL 1-3 could increase the anti-oxidative stress ability in the serum, liver, kidney and brain of aging mice, via increasing the total antioxidant capacity and the levels of anti-oxidative defense enzymes (superoxide dismutase, glutathione peroxidase, and catalase), and reducing the end product of lipid peroxidation (malondialdehyde). In the brain, in addition to the enhanced anti-oxidative stress via upregulating the level of the nuclear factor erythroid 2-related factor 2 and heme oxygenase 1, PL 1-3 could improve the dysfunction of the cholinergic system via reducing the active of acetylcholinesterase so as to increase the level of acetylcholine, increase the anti-inflammatory and anti-apoptosis activities via downregulating the expressions of pro-inflammatory cytokines (interleukin-6 and tumor necrosis factor-α) and pro-apoptosis proteins (Bcl-2 associated X protein and Caspase-3) in the D-gal-induced aging mice, to enhance the anti-aging ability via upregulating the expression of sirtuin 1 and downregulating the expressions of p53, p21, and p16. Besides, PL 1-3 could reverse the liver, kidney and spleen damages induced by D-gal in aging mice. These results suggested that PL 1-3 may be developed as an anti-aging drug for the prevention and intervention of age-related diseases

Effect of Lost-Foam Casting Process on Properties of Spiral Blade

The wear failure mode of a paver spiral blade was simulated by EDEM software. High-manganese steel, medium chromium alloy steel, and high chromium alloy steel were selected as matrix materials; SiC particles and WC particles were selected as surface particle reinforcement materials; and the spiral blade was prepared by the EPC process. The performance and wear mechanism of the spiral blade prepared by EPC were analyzed by microstructure, hardness, impact, pin disk, erosion wear test, and wear morphology. Modeling with EDEM software and applying the discrete element analysis method of particle system could simulate the actual working situation of the spiral blade of the paver well. Through the simulation, it was found that the wear amount of the spiral blade of the paver from the spiral shaft to the outside of the spiral blade was increasing. SiC and WC particle-reinforced wear-resistant coatings were prepared on the surfaces of high-manganese steel, medium chromium alloy steel, and high chromium alloy steel by the EPC method. The wear-resistant coating of high-manganese steel was 5.05 mm, the coating of medium chromium alloy steel was 5.98 mm, and the coating of high chromium alloy steel was 7.02 mm. The higher the chromium content, the better the diffusion with SiC and WC particles. In the process of the wear test, the soft phase in the coating was first worn away and concaved, and the hard phase protruded to bear the wear. After wear, it was found that the sample with high chromium alloy steel as matrix and SiC and WC particles as wear-resistant coating had the best wear resistance

Charge carrier relaxation model in disordered organic semiconductors

The relaxation phenomena of charge carrier in disordered organic semiconductors have been demonstrated and investigated theoretically. An analytical model describing the charge carrier relaxation is proposed based on the pure hopping transport theory. The relation between the material disorder, electric field and temperature and the relaxation phenomena has been discussed in detail, respectively. The calculated results reveal that the increase of electric field and temperature can promote the relaxation effect in disordered organic semiconductors, while the increase of material disorder will weaken the relaxation. The proposed model can explain well the stretched-exponential law by adopting the appropriate parameters. The calculation shows a good agreement with the experimental data for organic semiconductors

Effect of Lost-Foam Casting Process on Properties of Spiral Blade

The wear failure mode of a paver spiral blade was simulated by EDEM software. High-manganese steel, medium chromium alloy steel, and high chromium alloy steel were selected as matrix materials; SiC particles and WC particles were selected as surface particle reinforcement materials; and the spiral blade was prepared by the EPC process. The performance and wear mechanism of the spiral blade prepared by EPC were analyzed by microstructure, hardness, impact, pin disk, erosion wear test, and wear morphology. Modeling with EDEM software and applying the discrete element analysis method of particle system could simulate the actual working situation of the spiral blade of the paver well. Through the simulation, it was found that the wear amount of the spiral blade of the paver from the spiral shaft to the outside of the spiral blade was increasing. SiC and WC particle-reinforced wear-resistant coatings were prepared on the surfaces of high-manganese steel, medium chromium alloy steel, and high chromium alloy steel by the EPC method. The wear-resistant coating of high-manganese steel was 5.05 mm, the coating of medium chromium alloy steel was 5.98 mm, and the coating of high chromium alloy steel was 7.02 mm. The higher the chromium content, the better the diffusion with SiC and WC particles. In the process of the wear test, the soft phase in the coating was first worn away and concaved, and the hard phase protruded to bear the wear. After wear, it was found that the sample with high chromium alloy steel as matrix and SiC and WC particles as wear-resistant coating had the best wear resistance

A Novel Method for Deposition of Multi-Walled Carbon Nanotubes onto Poly(p-Phenylene Terephthalamide) Fibers to Enhance Interfacial Adhesion with Rubber Matrix

In order to enhance the interfacial adhesion of poly(p-phenylene terephthalamide) (PPTA) fibers to the rubber composites, a novel method to deposit multi-walled carbon nanotubes (MWCNTs) onto the surface of PPTA fibers has been proposed in this study. This chemical modification was performed through the introduction of epoxy groups by Friedel⁻Crafts alkylation on the PPTA fibers, the carboxylation of MWCNTs, and the ring-opening reaction between the epoxy groups and the carboxyl groups. The morphologies, chemical structures, and compositions of the surface of PPTA fibers were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results showed that MWCNTs were uniformly deposited onto the surface of PPTA fibers with the covalent bonds. The measurement of contact angles of the fibers with polar solvent and non-polar solvent indicated that the surface energy of deposited fibers significantly increased by 41.9% compared with the untreated fibers. An electronic tensile tester of single-filament and a universal testing machine were utilized to measure the strength change of the fibers after modification and the interfacial adhesion between the fibers and the rubber matrix, respectively. The results showed that the tensile strength had not been obviously reduced, and the pull-out force and peeling strength of the fibers to the rubber increased by 46.3% and 56.5%, respectively