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Effects of Calcium Ion on Adenovirus Production with High Densities of HEK293 Cells
Xuping Liu,Liang Zhao,Yigang Wang,Xu Zhang,Wen-Song Tan 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.3
One of the major restrictions on the production of adenoviral vectors (AdV) is due to the decrease in virus concentration concomitant with an increase in cell concentration at infection (CCI) which is known as “cell density effect”, this could be because of the limited access to the nutrients or significant accumulation of toxic by-products. However, current strategies, such as developing robust serum-free medium and performing nutrient feeding, will partially address this issue. Therefore, the objective of this study was to further optimize serum-free culture medium by exploring the influence of calcium ion on virus production. Our studies showed that an optimal concentration of calcium ion significantly enhances AdV production,especially at a high CCI. During the virus infection process,a high concentration of calcium ion (≥ 1 mM) caused a reduction in virus infection efficiency, possibly as a result of cell aggregation. However, by optimizing the timing of the addition of calcium ion (i.e., 12 hours post-infection [hpi]), high virus infection efficiency could be maintained. The addition of 0.1 to 2 mM calcium ion at 12 hpi increased virus proliferation dose-dependently. Therefore,the optimal selection of both the concentration and the supplementation time of calcium ion during the process of AdV production could minimize the “cell density effect,”and a 2.6- and 3.2-fold increase in virus concentration could be achieved at CCI3 and CCI4, respectively.
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Sanzhen Liu,Yao Li,Xuping Fu,Minyan Qiu,Bin Jiang,H ai W u,Rongyu Li,Yumin Mao,Yi Xie 생화학분자생물학회 2005 Experimental and molecular medicine Vol.37 No.2
The oligonucleotide microarray, a high-throughput polymorphism detection technology, holds great promise for the characterization of complex genetic variance. To achieve greater sensitivity and specificity for it to be an effective platform technology we present results and discuss some of the factors influencing signal intensities and single-mismatch discrimination in array-based mutation/SNP detection. Probes with a series of concentrations were spotted onto the slide in order to find the optimal concentration with the identifiable satisfying signals and the stable ratios between matched and mismatched probes. It was found that under our experimental conditions, when the initial probe concentration is higher than the maximum immobilization capability of the slide (7.5 µM), the hybridization signal will be saturated and the ratio between matched and mismatched probes will be more stable than at a lower probe concen-tration. Considering the cost of probes and the systematic stability, a constant spotting cone n-tration of 10 µM was selected. The stability of different types of mismatched oligo-DNA du-plexes on the glass surface was also confirmed. The results show that the order of stability of mismatched oligo-DNA duplexes on a glass surface is in general agreement with previous reports conducted using liquid and polyacryl-amide gel pads. This suggests that the influence of the mismatched base pair on the stability of the duplex in a solid hybridization system is similar to that in the solution hybridization environment.
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SYNTHESIS OF CaWO 4 AND CaWO 4 :Eu MICROSPHERES BY PRECIPITATION
YUGUO YANG,XUPING WANG,BING LIU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.1
Nearly monodisperse CaWO 4 and CaWO 4 :Eu 3 þmicrospheres have been synthesized in largescale by a surfactant-assisted solution route, in which cetyltrimethyl ammonium bromide(CTAB) is used. X-ray di®raction (XRD), scanning electron microscopy (SEM), Fourier trans-form infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photo-luminescence (PL) were used to characterize the resulting samples. The results of XRD indicatethat the CaWO 4 and CaWO 4 :Eu 3 þsamples have the scheelite structures. The growth process ofthese nearly monodisperse spheres with an average diameter around 3.2 ? m has been examined. The results of FTIR indicate that CTAB plays an important role in the formation of micro-spheres. The CaWO 4 microspheres exhibit a blue emission band with a maximum at 423 nm. Butthe CaWO 4 :Eu 3 þmicrospheres exhibit a red emission band with a maximum at 623 nm.
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Zhiyong Chen,Jianjun Lu,Xuping Li,Xuting Jin,Lijuan Shi,Miaoqing Liu,Zhilin Sun 한국고분자학회 2015 Macromolecular Research Vol.23 No.9
A novel 1,10-phenanthroline-functionalized polyimide (CMPI-Phen) was prepared as polymer matrix by the nucleophilic substitution reaction between chloromethylated polyimide (CMPI) and 5-amino-1,10-phenanthroline (NH2-Phen). Then, two kinds of luminescent materials of 1,10-phenanthroline-functionalized polyimide containing Eu(III) complexes, were obtained by two different methods. Their structures and properties were characterized by Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, inductively coupled plasma (ICP), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), luminescence spectrometry, and luminescence decay analysis. Investigations revealed that both the CMPI-Phen-Eu(III) and CMPI-Phen-Eu(TTA)3 display highly efficient red emissions, suggesting their potential application as luminescent materials. However, compared with CMPI-Phen-Eu(III), CMPI-Phen-Eu(TTA)3, where TTA stands for thenoyltrifluoroacetone, exhibits more excellent and stable fluorescence intensity and longer luminescence lifetime (134.30 μs). The weight-average molecular weights of CMPI-Phen-Eu(III) and CMPI-Phen- Eu(TTA)3 are 2.40×104 and 3.11×104, respectively. The Eu contents of CMPI-Phen-Eu(TTA)3 and CMPI-Phen-Eu(III) were measured by ICP to be 7.00% and 5.92%, respectively. TGA demonstrated that both CMPI-Phen-Eu(III) and CMPI-Phen-Eu(TTA)3 have high thermal stability and their 5% loss weight temperatures were 356 and 280 oC, respectively. Moreover, both CMPI-Phen-Eu(III) and CMPI-Phen-Eu(TTA)3 were soluble in polar solvents such as dimethylformamide (DMF), dimethylacetamide (DMAc), 1-methyl-2-pyrrolidone (NMP), and dimethylsulfoxide (DMSO) under heating conditions, and could be easily cast into tough thin films.
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