排序方式: 共有41条查询结果,搜索用时 15 毫秒
1.
A sensitive electrochemiluminescence (ECL) biosensor for the specific DNA sequence of hepatitis C virus (HCV) was developed based on the efficient quenching effect of the ferrocene cluster functionalized gold nanoparticles (Fc@AuNPs) on the ECL of electrodeposited silica@Ru(bpy)32+-chitosan-graphene oxide nanocomposite (SiO2@Ru−CS−GO). Graphene oxide (GO) can accelerate electron transfer rate, thus improving the ECL of Ru(bpy)32+ on electrode surface. The molecular beacons (MB) was fixed to SiO2@Ru−CS−GO by glutaraldehyde (GA) using the Schiff reaction between amino groups of chitosan (CS) and MB. The ECL of SiO2@Ru−CS−GO was depressed greatly by the Fc@AuNPs labelled at the end of MB, then, a stronger ECL was observed when the distance between Fc@AuNPs and SiO2@Ru−CS−GO increased after the hybridization of target DNA with MB. Under optimum conditions, the restored ECL intensity increased linearly with the target DNA concentration in the range of 1.0×10−16∼1.0×10−10 mol ⋅ L−1, and the limit of detection (LOD) is 1.4×10−17 mol ⋅ L−1. The proposed method exhibits acceptable stability and reproducibility. In general, the constructed HCV biosensor can be used for the sensitive detection of HCV in human serum, suggesting potential application prospects in bioanalysis. 相似文献
2.
Yuan Zhang Han Luo Qixing Lu Qiaoyu An You Li Shanshan Li Zongyuan Tang Baosheng Li 《中国化学快报》2021,32(1):393-396
We studied the cascade nucleophilic addition reactions of 1,2,3-triazines with activated acetonitriles or ketones,which were used to construct highly substituted pyridines that are not easily accessed by conventional methods.The strategy addressed some structural diversity issues currently facing medicinal chemistry,and the resulting pyridines could be used as convenient precursors for the synthesis of related pharmaceuticals.In particular,our method was applied to the syntheses of the marketed drug etoricoxib and several biologically important molecules in a few steps. 相似文献
3.
The aim of this paper is to study the qualitative behavior of large solutions to the following problem
4.
This paper deals with the second term asymptotic behavior of large solutions to the problems Δu=b(x)f(u), x∈Ω, subject to the singular boundary condition u(x)=∞, x∈∂Ω, where Ω is a smooth bounded domain in RN, and b(x) is a non-negative weight function. The absorption term f is regularly varying at infinite with index ρ>1 (that is limu→∞f(ξu)/f(u)=ξρ for every ξ>0) and the mapping f(u)/u is increasing on (0,+∞). Our analysis relies on the Karamata regular variation theory. 相似文献
5.
The preconcentration and voltammetric behavior of BiIII on a sodium humate modified carbon paste electrode was studied by means of cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV). The proposed measurement involves an initial nonelectrolytic preconcentration step in which BiIII is complexed by the surface modifier in a solution of 0.05 M KNO3-0.0106 M HNO3 (pH 2.0) and a subsequent electrochemical scan step in which the preconcentrated BiIII was reduced and then oxidized promptly in supporting electrolyte of 0.5 M HNO3. The resulting DPSV anodic current was proportional to the concentration of BiIII ion over the range of 4.78 × 10−8–1.44 × 10−5 M. The detection limit was 4.78 × 10−8 M. The proposed method was used to determine bismuth in various samples. Various factors affecting the electrode behavior were also investigated at the same time. 相似文献
6.
A visible light driven Cu(I)‐catalyzed intermolecular oxyamination of electron‐deficient olefins has been achieved by using O‐benzoylhydroxylamines as donors both for amine and oxygen. The transformation properties afford mild conditions and a wide substrate scope, providing access to ester derivatives of β‐amino alcohols with good yields and high regioselectivity. 相似文献
7.
Nonlinear Dynamics - This paper reports on the sliding mode control (SMC) problem for nonlinear stochastic systems with one features: time-delays are not only varied with time but also... 相似文献
8.
A new type of ethoxylated double‐tail trisiloxane surfactants containing a propanetrioxy spacer of the general formula ROCH2CH(OR)CH2O(CH2CH2O)xCH3 [R = Me3SiOSiMe(CH2)3OSiMe3, x = 8.4, 12.9, 22] has been synthesized. Their structures were characterized by 1H‐NMR, 13C‐NMR and 29Si‐NMR spectroscopy. The critical micelle concentration (CMC) values of these double‐tail trisiloxane surfactants were at the level of 10−5 mol l−1, and the surface tension values of their aqueous solutions at CMC were in the range of 21‐24.9 mN m−1. Only the double‐tail trisiloxane surfactant with average ethoxy units of 8.4 ( 1P ) possesseda good spreading ability (SA) value. Its SA values of aqueous solutions (5.0 × 10−3 mol l−1) on parafilm and Ficus microcarpa leaf surfaces were more than 15 (within 10 min) and 13 (within 3 min), respectively. The trisiloxane surfactant 1P was also found to have the strongest hydrolysis resistant ability among all of the double‐tail trisiloxane surfactants prepared. Its aqueous solutions were stable for 130 days in an acidic environment (pH 4.0) and 59 days in an alkaline environment (pH 10.0) with surface tension values less than 23 mN m−1. It is suggested that this surfactant can be used as a wetting agent or spreading agent in certain extreme pH environments. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
9.
Vindi M. Jayasinghe-Arachchige Qiaoyu Hu Gaurav Sharma Thomas J. Paul Marcus Lundberg David Quinonero Tatjana N. Parac-Vogt Rajeev Prabhakar 《Journal of computational chemistry》2019,40(1):51-61
In this study, mechanisms of hydrolysis of all four chemically diverse cleavage sites of human serum albumin (HSA) by [Zr(OH)(PW11O39)]4− (ZrK) have been investigated using the hybrid two-layer QM/MM (ONIOM) method. These reactions have been proposed to occur through the following two mechanisms: internal attack (IA) and water assisted (WA). In both mechanisms, the cleavage of the peptide bond in the Cys392-Glu393 site of HSA is predicted to occur in the rate-limiting step of the mechanism. With the barrier of 27.5 kcal/mol for the hydrolysis of this site, the IA mechanism is found to be energetically more favorable than the WA mechanism (barrier = 31.6 kcal/mol). The energetics for the IA mechanism are in line with the experimentally measured values for the cleavage of a wide range of dipeptides. These calculations also suggest an energetic preference (Cys392-Glu393, Ala257-Asp258, Lys313-Asp314, and Arg114-Leu115) for the hydrolysis of all four sites of HSA. © 2018 Wiley Periodicals, Inc. 相似文献
10.
Qiaoyu Sun C. Wang Liangxi Li Hulin Li 《Fresenius' Journal of Analytical Chemistry》1999,363(1):114-117
A chemically modified carbon paste electrode was prepared by incorporating appropriate amounts of sodium humate(NaA). Palladium(II)
was selectively accumulated in a solution of Britton-Robinson(B-R) buffer (pH 2.8) onto the electrode surface in open circuit
mode. The subsequent electrochemical measurement was carried out by cyclic voltammetry (CV) and linear sweep anodic stripping
voltammetry (LSASV) in a supporting electrolyte of 1.0 M HCl. The obtained oxidation currents (Ipa1 and Lpa2) were proportional to the Pd(II) concentration in the range of 4.7 × 10–6 - 9.4 × 10–8 M. The developed method was applied to the quantitative determination of palladium in real samples.
Received: 6 March 1998 / Revised: 3 June 1998 / Accepted: 3 July 1998 相似文献