RESUMO
Herein, we have used a hollow fiber membrane as a support layer material to encapsulate paraffin in order to prepare a phase change energy storage material. The phase change energy storage materials with three different support layers were successfully prepared and various properties were systematically characterized. There are also few reports on the use of hollow fiber membranes as the support carrier for the preparation of phase change energy storage materials. The significance of this work is in exploring the use of hollow fiber membranes as a support layer to prepare phase change energy storage materials. In addition, the choice of support carriers for phase change energy storage materials was enriched. Both the hollow fiber membrane columnar hollow portion and the pore structure of the membrane wall could be used to encapsulate paraffin, which makes it more advantageous than the other support materials. The SEM characterization confirmed that paraffin was successfully encapsulated on the membrane wall and columnar hollow part of the membranes. The TGA results indicate that the introduction of the membrane as an encapsulation carrier delayed the decomposition of the composite phase change energy storage materials. The activation energy during the decomposition in the three different phase change energy storage materials was calculated by the decomposition kinetics. Among the three fiber membranes explored in this work, the polypropylene (PP) encapsulation membrane performed better than the other two encapsulation membranes in terms of encapsulation content of paraffin, porosity, latent heats, thermal stability, and activation energy.
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OBJECTIVES: The Jing people are a recognized ethnic group in Guangxi, southwest China, who are the immigrants from Vietnam during the 16th century. They speak Vietnamese but with lots of language borrowings from Cantonese, Zhuang, and Mandarin. However, it's unclear if there is large-scale gene flow from surrounding populations into Jing people during their language change due to the very limited genetic information of this population. MATERIALS AND METHODS: We collected blood samples from 37 Jing and 3 Han Chinese individuals from Wanwei, Shanxin, and Wutou islands in Guangxi and genotyped about 600,000 genome-wide single nucleotide polymorphisms (SNPs). We used Principal Component Analysis (PCA), ADMIXTURE analysis, f statistics, qpWave and qpAdm to infer the population genetic structure and admixture. RESULTS: Our data revealed that the Jing people are genetically similar to the populations in southwest China and mainland Southeast Asia. But compared with Vietnamese, they show significant evidence of gene flow from surrounding East Asians. The admixture proportion is estimated to be around 35-42% in different Jing groups using southern Han Chinese as a proxy. The majority of the paternal lineages of Jing people are most likely from surrounding East Asians. DISCUSSION: We conclude that the formation and language change of present-day Jing people have involved genetic assimilation of surrounding East Asian populations. The language borrowing, in this case, is not only a cultural phenomenon but has involved demic diffusion.
Assuntos
Povo Asiático/genética , Fluxo Gênico/genética , Idioma , Antropologia Física , China/etnologia , Feminino , Genética Populacional , Humanos , Masculino , Análise de Componente Principal , Vietnã/etnologiaRESUMO
In this research, a reduction-degradable supramolecular micelle delivery system of camptothecin (CPT) was developed to enhance the stability of CPT in aqueous media. Firstly, Michael addition polymerization occurred between N, N'-bis(acryloyl) cystamine (BAC) and mono(6-(2-aminoethyl)amino-6-deoxy)-ß-cyclodextrin (CDen) to produce the reduction-degradable polymer of BAC-CDen. And adamantyl-modified polyethylene glycol monomethyl ether (mPEG-Ad) was further encapsulated into it to gain supramolecular micelles of mPEG-Ad@BAC-CDen. Then mPEG-Ad@BAC-CDen/CPT supramolecular micelles could be easily obtained by incorporation of CPT into mPEG-Ad@BAC-CDen via dialysis method. The particle size of supramolecular micelles increased from 106 nm (bare micelles) to 142 nm (CPT loaded micelles), suggesting their passive targeting potential to tumor tissue. Owing to the reduction degradability of disulfide linker in main chain of BAC-CDen, the CPT could be sustainably released from the above micelles with the gradual cleavage of polymer in the presence of dithiothreitol (DTT) at the concentration of simulating the intracellular condition. It was noted that the stability of CPT in aqueous media was remarkably improved in the mPEG-Ad@BAC-CDen supramolecular micelles, which effectively protected the active lactone ring of CPT from hydrolysis under physiological condition. Besides, compared with free CPT, the CPT-loaded supramolecular micelles showed much lower cytotoxicity against L929 cell line. All these results suggested the potential utilization of the mPEG-Ad@BAC-CDen supramolecular micelles as the carriers of hydrophobic drugs with better stability and lower cytotoxicity. And the resulted anti-tumor CPT supramolecular micelles can be delivered to tumor cells with a high selectivity.