A new triple porosity seepage model in coalbed

Based on the analysis of macro and micro structure of the coalbed and comprehensive research on dual-porosity and triple-porosity models at home and abroad,three new triple-porosity models were proposed by considering the geological characteristics of coalbe

Effects of crop species richness on the community of soil nematodes in an experimental agro-ecosystem

Biodiversity losses in terrestrial ecosystems may negatively affect the functioning of underground ecosystems, especially in trophic interaction networks. These effects have mainly been found in grassland ecosystems. The responses of underground agro-ecosystems to biodiversity loss are largely unknown. Here, the relationships between crop species diversity and the abundance, diversity and functional indices of soil nematodes were examined in a 4-yr field experiment across five crop species richness levels (1, 2, 4, 8, and 16). The relationships between crop biomass and nematode abundance or ecological indices were also tested. Crop species richness had no significant effects on either total abundance nematode, nematode abundance within each trophic group, or nematode ecological indices. However, the plant parasitic nematodes, Psilenchus and Partylenchus, significantly differed among crop species diversity. Crop biomass significantly increased the abundances of total nematodes, plant parasites and omnivores/predators, and decreased that of fungivores. Furthermore, the responses of PPI (Maturity index of plant-parasitic nematode), EI (Enrichment index), and SI (Structure index) to crop biomass were positive, although CI (Channel index) was negatively affected. Redundancy analysis (RDA) further showed that crop species diversity and crop biomass account for 0.7% and 1.9% of the variation in nematode abundance, respectively. Our results clearly indicate that soil nematode abundance and community composition was more affected by crop biomass than by crop species diversity in agricultural systems. (C) 2016 Elsevier Masson SAS. All rights reserved

Preparation, characterization and application of star-shaped PCL/PEG micelles for the delivery of doxorubicin in the treatment of colon cancer

Xiang Gao,1 BiLan Wang,1 XiaWei Wei,1 Wang Rao,2 Fang Ai,2 Fen Zhao,2 Ke Men,1 Bowen Yang,1 Xingyu Liu,1 Meijuan Huang,1 Maling Gou,1 ZhiYong Qian,1 Ning Huang,1 Yuquan Wei11Department of Pathophysiology, College of Preclinical and Forensic Medical Sciences, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, People's Republic of China; 2Department of Surgery, First Affiliated Hospital, Xinxiang Medical School, Xinxiang, People's Republic of ChinaAbstract: Star-shaped polymer micelles have good stability against dilution with water, showing promising application in drug delivery. In this work, biodegradable micelles made from star-shaped poly(ε-caprolactone)/poly(ethylene glycol) (PCL/PEG) copolymer were prepared and used to deliver doxorubicin (Dox) in vitro and in vivo. First, an acrylated monomethoxy poly (ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) diblock copolymer was synthesized, which then self-assembled into micelles, with a core-shell structure, in water. Then, the double bonds at the end of the PCL blocks were conjugated together by radical polymerization, forming star-shaped MPEG-PCL (SSMPEG-PCL) micelles. These SSMPEG-PCL micelles were monodispersed (polydispersity index = 0.11), with mean diameter of ≈25 nm, in water. Blank SSMPEG-PCL micelles had little cytotoxicity and did not induce obvious hemolysis in vitro. The critical micelle concentration of the SSMPEG-PCL micelles was five times lower than that of the MPEG-PCL micelles. Dox was directly loaded into SSMPEG-PCL micelles by a pH-induced self-assembly method. Dox loading did not significantly affect the particle size of SSMPEG-PCL micelles. Dox-loaded SSMPEG-PCL (Dox/SSMPEG-PCL) micelles slowly released Dox in vitro, and the Dox release at pH 5.5 was faster than that at pH 7.0. Also, encapsulation of Dox in SSMPEG-PCL micelles enhanced the anticancer activity of Dox in vitro. Furthermore, the therapeutic efficiency of Dox/SSMPEG-PCL on colon cancer mouse model was evaluated. Dox/SSMPEG-PCL caused a more significant inhibitory effect on tumor growth than did free Dox or controls (P < 0.05), which indicated that Dox/SSMPEG-PCL had enhanced anticolon cancer activity in vivo. Analysis with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) showed that Dox/SSMPEG-PCL induced more tumor cell apoptosis than free Dox or controls. These results suggested that SSMPEG-PCL micelles have promising application in doxorubicin delivery for the enhancement of anticancer effect.Keywords: drug delivery, star-shaped polymer, MPEG-PCL, CM

Mouse oocyte vitrification: the effects of two methods on maturing germinal vesicle breakdown oocytes

Purpose Evaluation of viability and subsequent developmental ability of mouse germinal vesicle breakdown oocytes vitrified in conventional straws. Methods Oocytes with compact cumulus cells were cultured for 3 h in TCM199 medium GVBD and vitrified by two methods: the step-wise and single-step. After vitrification, the oocytes were thawed, and subjected to in vitro maturation and in vitro fertilization. Oocyte survival (postthaw) was assessed by morphological appearance and staining, using propidium iodide (PI)/Hoechst 33342. The oocyte maturation and fertilization rates were examined in vitro. Results In the single-step method the rates of post thaw survival, maturation to metaphase II and cleavage (2-cell embryos) were 58.68%, 56.41% and 38.63%, respectively. In the step-wise method, the corresponding rates were 81.75%, 68.59% and 51.80%, respectively. Conclusion Vitrification of mouse germinal vesicle breakdown oocytes by the step-wise method had the advantag