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951.
Kedong Song Dan Ge Shui Guan Chenggong Sun Xuehu Ma Tianqing Liu 《Applied biochemistry and biotechnology》2014,174(6):2114-2130
The aim of this study is to analyze the growth and substance metabolism of neural stem cells (NSCs) cultured in biological collagen-based scaffolds. Mass transfer and metabolism model of glucose, lactic acid, and dissolved oxygen (DO) were established and solved on MATLAB platform to obtain the concentration distributions of DO, glucose, and lactic acid in culture system, respectively. Calculation results showed that the DO influenced their normal growth and metabolism of NSCs mostly in the in vitro culture within collagen-based scaffolds. This study also confirmed that 2-mm thickness of collagen scaffold was capable of in vitro cultivation and growth of NSCs with an inoculating density of 1?×?106 cells/mL. 相似文献
952.
Nan Shen Shi-Jie Yuan Chao Wu Yuan-Yuan Cheng Xiang-Ning Song Wen-Wei Li Zhong-Hua Tong Han-Qing Yu 《Applied biochemistry and biotechnology》2014,173(2):461-471
In this study, 27 strains of electrochemically active bacteria (EAB) were rapidly isolated and their capabilities of extracellular electron transfer were identified using a photometric method based on WO3 nanoclusters. These strains caused color change of WO3 from white to blue in a 24-well agar plate within 40 h. Most of the isolated EAB strains belonged to the genera of Aeromonas and Shewanella. One isolate, Pantoea agglomerans S5-44, was identified as an EAB that can utilize acetate as the carbon source to produce electricity and reduce azo dyes under anaerobic conditions. The results confirmed the capability of P. agglomerans S5-44 for extracellular electron transfer. The isolation of this acetate-utilizing, facultative EBA reveals the metabolic diversity of environmental bacteria. Such strains have great potential for environmental applications, especially at interfaces of aerobic and anaerobic environments, where acetate is the main available carbon source. 相似文献
953.
The copolymer of acrylamide and 3-[N-(2-methacryloxylethyl)-N,N-dimethylammonio]-propane sulfonate (PAM-MDMPS) was prepared via free radical copolymerization. Solubility of the copolymers was studied by turbidimetric titration method under different conditions. It was found for the first time that the critical salt concentration to dissolve the copolymer showed a plateau over one order of magnitude up to the critical overlap concentration. Rheological behavior and chain conformation of the copolymers in 1 M NaCl solution were also studied. The concentration regions according to scaling theory were found the same as neutral polymers in good solvent. The specific viscosities could be normalized by the overlap parameter. According to the Huggins relation, the copolymers adopted a more compact conformation in 1 M NaCl with increasing MDMPS content due to the hydrophobic association of the betaine unit in the macromolecular backbone, which was stabilized by the strongly hydrated dipolar pendant chains. 相似文献
954.
Shijun Wang Linyong Song Pengpeng Chen Yifeng Zhou Wangyan Nie 《Colloid and polymer science》2014,292(10):2465-2473
To investigate the effect of surface functionality on the morphology of polymer/silica composite, poly(styrene-alt-maleic anhydride) (SMA) spheres prepared via precipitation polymerization method was employed. In water/ethanol solution, diethanolamine (DEA) was used to catalyze the hydrolysis reaction of tetraethoxysilane (TEOS), and rambutan-like poly(styrene-alt-maleic anhydride)/silica (SMA/SiO2) microspheres were synthesized through in situ sol–gel process. The obtained structure and morphology were characterized by FTIR, NMR, TEM, SEM, and TGA. The results showed that the hydrolyzed SMA chains on the surface was crucial to the nucleation and growth of silica, and the morphologies of SMA/SiO2 composite microspheres can be controlled by the amount of DEA and the ratio of SMA/TEOS. In addition, the SMA/SiO2 microspheres were used to prepare hierarchical structure of SMA/SiO2/Ag particles, which were utilized for the construction of surface-enhanced Raman scattering substrate (SERS). 相似文献
955.
Hongfang Wang Cong Wu Xu Liu Jing Sun Guangmei Xia Wei Huang Rui Song 《Colloid and polymer science》2014,292(11):2949-2957
Herein, a facile and noncovalent modification for multiwalled carbon nanotubes (MWNTs) is adopted by the self-polymerization of dopamine (DOPA). And, the polydopamine-coated MWNTs (D-MWNTs) were further incorporated into poly(l-lactide) (PLLA) matrix through the solvent-casting method. It is found that the D-MWNTs tend to be well dispersed in PLLA matrix than the pristine MWNTs and the D-MWNTs that can act as heterogeneous nucleators that evidently affect the morphology and crystallization behavior of PLLA. In addition, the significant improvement of dispersion and the interface interaction of PLLA/D-MWNTs, via dopamine coating between the MWNTs and PLLA matrix, results in enhanced mechanical and thermal properties and electrical conductivity. This facile methodology is believed to afford broad application potential in carbon nanotubes (CNTs)-based polymer nanocomposites. 相似文献
956.
957.
采用原子荧光法测定茶叶中的硒含量,对样品消解温度及仪器条件进行了优化。还原剂为1.0%硼氢化钾–0.5%氢氧化钾溶液,载流液为3%盐酸溶液。在优化条件下,硒的质量浓度在0~20 ng/mL范围内与荧光强度呈良好的线性关系,相关系数r=0.999,检出限为0.8 ng/mL。该法的加标回收率为88.08%~101.39%,测定结果的相对标准偏差为2.03%~4.84%(n=6)。该方法实际操作性强,准确度高,适用于日常检验工作中对批量茶叶中硒含量的测定。 相似文献
958.
在人体生理pH条件下,利用紫外吸收光谱和荧光光谱研究了槲皮素(QUE)、大豆甙元(DAI)、4′,7-二甲氧基-3′-异黄酮磺酸钠(DISS)和3′-大豆甙元磺酸钠(DSS)四种黄酮类化合物与牛血清白蛋白(BSA)的相互作用,结合反应机理对其进行了初步探讨;并计算了结合位点数和结合常数.紫外吸收光谱分析结果表明,在pH=7.4条件下,黄酮类化合物中疏水性的苯环与BSA疏水腔中的氨基酸残基发生作用,从而导致药物分子的吸收峰红移,用Scatchard拟合法可求得DAI及DSS与BSA的结合常数.荧光光谱分析结果表明,BSA对DAI、DISS和DSS均有明显的敏化增强效应,计算得到的增强速率常数分别为1.39×1011,7.72×1011和1.93×1012L·s-1·mol-1,并可求得结合位点数和结合常数. 相似文献
959.
960.
Dr. Huizeng Li Wei Fang Zhipeng Zhao An Li Dr. Zheng Li Prof. Mingzhu Li Prof. Qunyang Li Prof. Xiqiao Feng Prof. Yanlin Song 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(26):10622-10626
Precise separation and localization of microdroplets are fundamental for various fields, such as high-throughput screening, combinatorial chemistry, and the recognition of complex analytes. We have developed a droplet self-splitting strategy to divide an impacting droplet into predictable microdroplets and deposit them at preset spots for simultaneous multidetection. No matter exchange was observed between these microdroplets, so they could be manipulated independently. Droplet self-splitting was attributed to anisotropic liquid recoiling on the patterned adhesive surface, as influenced by the droplet Weber number and the width of the low-adhesive stripe. A quantitative criterion was also developed to judge the droplet self-splitting capability. The precise separation and distribution of microdroplets enabled simultaneous arrayed reactions and multiple analyte detection using one droplet of sample. 相似文献