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排序方式: 共有161条查询结果,搜索用时 21 毫秒
21.
Various strategies have been proposed for the detection of disease protein biomarkers; however, most methods are too expensive, cumbersome or limited in sensitivity for clinical use. Here, we report that a fabricated complex can be used as a powerful tool to detect trace proteins in complex samples. In this strategy, a DNA–protein complex that comprises of one target molecule and two or more deoxyribozyme-containing probes can exhibit autonomous cleavage behavior on the surface of the substrate DNA modified electrode. In the meantime, the complex can remove the cleaved DNA fragment from the electrode surface by taking advantage of the proximity effect. The proposed approach allows one-step and highly sensitive detection of a variety of targets based on the changes of the direct electrochemical readout. Moreover, this method may also have considerable advantages over the commonly reported DNA amplification-assisted immunoassays, particularly in terms of assay simplicity and cost, which may hold great potential for application in resource-constrained regions. 相似文献
22.
Zheng X Zhang L Li J Luo S Cheng JP 《Chemical communications (Cambridge, England)》2011,47(45):12325-12327
Magnetic polyoxometalates (POMs) are obtained by a simple sonication between functionalized magnetic nanoparticles and polyoxometalates. This material can be used not only as a highly active acid catalyst, but also as a catalyst support for chiral amines. 相似文献
23.
Minkai?Zhao Xiaoxi?ZuoEmail author Chengyun?Wang Xin?Xiao Jiansheng?Liu Junmin?NanEmail author 《Ionics》2016,22(11):2123-2132
The preparation of polyethylene-supported poly(vinylidene fluoride)/cellulose acetate butyrate/nano-SiO2 particle (PVDF-CAB-SiO2/PE) blended gel polymer electrolytes (GPEs) is reported here. The electrolyte uptake, mechanical properties, thermal stability, and electrochemical performance of these electrolytes are characterized to evaluate their potential application in lithium-ion batteries (LIBs). The results indicate that the particle size of SiO2 can be adjusted by the tetraethyl orthosilicate (TEOS) concentration and affects the physicochemical properties of the membrane. By doping 5 wt.% SiO2 (500 nm) into the PVdF-CAB blended polymer, the porosity of the membrane increases from 40 to 42.3 %, the mechanical strength from 117.3 to 138.7 MPa, the electrolyte uptake from 149 to 195 %, the oxidation decomposition potential from 4.7 to 5.2 V, and the ionic conductivity of the corresponding GPE is improved from 1.16 to 2.98 mS cm?1 at ambient temperature. The PVDF-CAB-SiO2/PE-based GPE and the two electrodes are suitably compatible, and the thermal stability is higher than that of the polyethylene (PE) membrane. The LIBs with the as-prepared GPE also exhibit enhanced discharge capacity and cycle stability, indicating the promising application of these GPEs in LIBs. 相似文献
24.
Xi Luo Lijun Zhu Wei Wu Xiaoxi Sheng Ningfang Cai Shikun Liu Zeneng Cheng 《Chromatographia》2009,70(7-8):1215-1219
A liquid chromatographic method for the simultaneous determination of 6β-hydroxycortisol and 6β-hydroxycortisone using dexamethasone as internal standard in human urine is described. Separation was achieved on a reversed-phase C18 column by a gradient elution of acetonitrile and water containing 0.1% formic acid. 6β-Hydroxycortisol and 6β-hydroxycortisone were monitored by UV absorption at 244 nm. The lower limits of quantitation were 5 ng mL?1 for both analytes. The intra-day and inter-day relative standard deviations were less than 7.4%. Accuracy determined at three concentrations ranged between 92.16 and 109.77%. The sensitivity, specificity and accuracy of this method were demonstrated to be satisfactory for measuring both metabolites in human urine. 相似文献
25.
Click chemistry has been employed to construct a library of the pyrrolidine-type asymmetric organocatalysts. The clicked organocatalysts were evaluated in asymmetric Michael addition of ketones to nitroolefins, showing good catalytic activity and stereoselectivity (up to 100% yield, syn:anti = 99:1, 96% ee). 相似文献
26.
Xiaoxi Qiao Xiangjun Zhang Yanbao Guo Shikuan Yang Yu Tian Yonggang Meng 《Rheologica Acta》2013,52(10-12):939-947
Carbon nanotube (CNT)-doped liquid crystals (LCs) have attracted intensive research studies as prospective materials in optic display devices, microfluidic sensors, and lubricants due to their unique molecular structures and properties. In this paper, the interaction between the doped CNTs and the hosting 4-cyano-4 $^{\prime }$ -pentylbiphenyl (5CB) molecules (in both nematic and isotropic phases) was investigated and we focused on the boundary layer rheological properties of the CNT-doped 5CB under external electric field. The experiments were performed by using a quartz crystal microbalance (for boundary layer viscosity investigation) and a rheometer (for bulk viscosity measurement). The results indicate that the bulk viscosity of the CNT-doped 5CB presents an obvious electroviscous effect in its nematic phase while no electroviscous effect in its isotropic phase. Additionally, we found that the boundary layer viscosity of the CNT-doped 5CB demonstrated significant electroviscous effects both in its nematic phase and isotropic phase. The enhanced electroviscous effects on the boundary layer viscosity of CNT-doped 5CB can be attributed to the highly ordered structures of LC molecules and CNTs on the substrate under external electric field. The unique properties of the boundary layer rheology of CNT-doped 5CB LC were further discussed in view of the ordering of LC molecules induced by the electric field, the polarity of CNTs, and the aligning interaction between CNTs and LC molecules. 相似文献
27.
28.
Shiteng Suo Xiaoxi Chen Lianming Wu Xiaofei Zhang Qiuying Yao Yu Fan He Wang Jianrong Xu 《Magnetic resonance imaging》2014
Purpose
To evaluate the non-Gaussian water diffusion properties of prostate cancer (PCa) and determine the diagnostic performance of diffusion kurtosis (DK) imaging for distinguishing PCa from benign tissues within the peripheral zone (PZ), and assessing tumor lesions with different Gleason scores.Materials and Methods
Nineteen patients who underwent diffusion weighted (DW) magnetic resonance imaging using multiple b-values and were pathologically confirmed with PCa were enrolled in this study. Apparent diffusion coefficient (ADC) was derived using a monoexponential model, while diffusion coefficient (D) and kurtosis (K) were determined using a DK model. Differences between the ADC, D and K values of benign PZ and PCa, as well as those of tumor lesions with Gleason scores of 6, 7 and ≥ 8 were assessed. Correlations between parameters D and K in PCa were analyzed using Pearson’s correlation coefficient. ADC, D and K values were correlated with Gleason scores of 6, 7 and ≥ 8, respectively.Results
ADC and D values were significantly (p < 0.001) lower in PCa (0.79 ± 0.14 μm2/ms and 1.56 ± 0.23 μm2/ms, respectively) compared to benign PZ (1.23 ± 0.19 μm2/ms and 2.54 ± 0.24 μm2/ms, respectively). K values were significantly (p < 0.001) greater in PCa (0.96 ± 0.20) compared to benign PZ (0.59 ± 0.08). D and K showed fewer overlapping values between benign PZ and PCa compared to ADC. There was a strong negative correlation between D and K values in PCa (Pearson correlation coefficient r = − 0.729; p < 0.001). ADC and K values differed significantly in tumor lesions with Gleason scores of 6, 7 and ≥ 8 (p < 0.001 and p = 0.001, respectively), although no significant difference was detected for D values (p = 0.325). Significant correlations were found between the ADC value and Gleason score (r = − 0.828; p < 0.001), as well as the K value and Gleason score (r = 0.729; p < 0.001).Conclusion
DK model may add value in PCa detection and diagnosis. K potentially offers a new metric for assessment of PCa. 相似文献29.
Xiaohua Zhu Haiying Wang Qifang Jiao Xin Xiao Xiaoxi Zuo Yong Liang Junmin Nan Jufang Wang Lishi Wang 《Particle & Particle Systems Characterization》2014,31(7):771-777
Zero‐dimensional fluorescent carbon dots (CDs) that are used as a cell‐imaging reagent are prepared by using a simple and effective route employing lithium‐intercalated graphite from lithium‐ion batteries as a carbon source. Under ultrasonic exfoliation, the interlayer space increases, while the layer distortion and remaining lithium of the lithium‐intercalated graphite are utilized to disrupt the graphitic structure and produce the CD suspension. Subsequently, after concentration and purification, the obtained colloidal CD suspension has a fluorescent yield of up to 1.2% and is therefore comparable to the CDs prepared in previous reports. These CD products are water‐soluble, nanosized (approximately 3.5 nm), and biocompatible and can easily enter into HeLa cells to act as a cell‐imaging reagent without any further functionalization. In addition, these CDs do not impose toxicity against HeLa cells and have high photostability with low photobleaching and demonstrate potential applications for bio‐labeling as well as solution state optoelectronics. 相似文献
30.
Xiaohua Zhu Xin Xiao Xiaoxi Zuo Yong Liang Junmin Nan 《Particle & Particle Systems Characterization》2014,31(7):801-809
Zero‐dimensional photoluminescent (PL) graphene quantum dots (GQDs) that can be used as the cell‐imaging reagent are prepared by a hydrothermal route using the graphene oxide (GO) as the carbon source. Under the optimized hydrothermal conditions, an initial hydrogen peroxide concentration of 0.5 mg mL?1 at 180 °C for 120 min, the GO sheets can be cut into nanocrystals with lateral dimensions in the range of 1.5–5.5 nm and an average thickness of around 1.1 nm. The as‐prepared GQDs exhibit an abundance of hydrophilic hydroxy and carboxyl groups and emit bright blue luminescence with up‐conversion properties in a water solution at neutral pH. Most interestingly, they indicate excitation‐independent emission characteristics, and the surface state is demonstrated to have a key role in the PL properties. The fluorescence quantum yield of the GQDs is tested to be around 6.99% using quinine sulfate as a standard. In addition, the as‐prepared GQDs can enter into HeLa cells easily as a fluorescent imaging reagent without any further functionalization, indicating they are aqueous stability, biocompatibility, and promising for potential applications in biolabeling and solution state optoelectronics. 相似文献