Abstract:In this work, racemic hybrid polypeptides poly(ethylene glycol) (PEG)-bpoly(racemic-leucine) (PRL) copolymers with different leucine residues have been synthesized and characterized. Using docetaxel as a model molecule, the high drug-loaded spherical micelles based on PEG-PRL were prepared successfully using dialysis, with a tunable particle size from 170 nm to 250 nm obtained by changing the length of the hydrophobic blocks. Facilitated drugloading behavior (higher drug-loading ability and easier drug-loading process) of PEG-PRL compared with their corresponding levo forms (PEG-b-poly[levo leucine]) was observed and clarified for the first time. With this facilitation, the highest drug-loading content and efficiency of PEG-PRL micelles can achieve 11.2% ± 0.4% and 67.2% ± 2.4%, respectively. All drugloaded PEG-PRL micelles exhibit a similar release behavior with a sustained release up to 72 hours. The PEG-PRL was shown to be nontoxic against MCF-7 and human umbilical vein endothelial cells up to a concentration of 100 μg/mL, displaying a good biocompatibility. Also, the docetaxel-loaded PEG-PRL micelles were more toxic than the free drug against MCF-7 human breast cancer cells -both dose and time dependent. Therefore, these high docetaxel-loaded micelles based on racemic hybrid polypeptides appear to be a novel promising nanomedicine for anticancer therapy.
Using a soil column experiments to analyze the influence of different density of one dimension vertical infiltration of water infiltration rate, cumulative infiltration and wetting front. The experimental results showed that the bulk density of the infiltration rate, cumulative infiltration and wetting front has a significant impact. Infiltration rate, cumulative infiltration and wetting front were decreased with increasing density in the same period of infiltration. The greater the soil bulk capacity, the larger the infiltration decrease ration μ and η, respectively compared to the based accumulative infiltration and the based wetting front depth.
For the problems that the characteristics of diary return water time series in Ningxia Qingtongxia Irrigation area ,this issue studied it by using time series analysis, phase space reconstruction and saturation correlation dimension and other methods.The research results showed that diary return water time series in Qingtongxia irrigation area is a non-white noise stationary time series, and it has the chaotic characteristics, the saturation correlation dimension of it is 1.81, the embedding dimensionality of it is 9.
1D or 3D nanoZnO crystals were prepared in diethylene glycol (DEG) via solvothermal process without surfactants at 160oC. Zinc acetate dihydrate was elected as zinc source, while water, sodium hydroxide, or ammonia solution was respectively as assistant agents. The morphologies of the products were characterized by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). With a certain content of water or sodium hydroxide, 1D ZnO nanorods were gained, having diameters of 20-90 nm and lengths of 0.04-1.8μm. With a certain content of ammonia solution, 3D shiitake-like ZnO hierarchical structures were gained. The pileus of shiitake structure composes of nanorods with diameters of 35-40 nm, while the stipe composes of one hexagonal rod with diameters of 250-350nm, or many hexagonal rods with diameters of 100-200nm. The morphology and size could be regulated by changing the amount of water, NaOH, or ammonia solution. Solvothermal process in high-viscosity solvent may provide a facile method for preparing nanomaterials.
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