Chromatographia - The present work deals with the optimization, validation and application of a versatile HPLC–DAD method for concurrent estimation of nine antimicrobials and proton pump... 相似文献
Nonlinear Dynamics - Fault features extraction method for slight misalignment of rotor systems is researched in this paper. When a rotor system with faults is excited by harmonic inputs, system... 相似文献
The adsorption and photocatalytic degradation of Ethyl methylphosphonate (EMPA) on powdery TiO2 film has experimentally investigated using attenuated total reflection-infrared Fourier transform spectroscopy (ATR-FTIR) in ambient condition. Characteristic IR frequency as P-O-C vibration mode as EtO was observed by EMPA adsorbed at the surface of TiO2. By TiO2 photocatalysis, the adsorbed EMPA was decomposed to methyl phosphonic acid and phosphoric acid. The increment of IR intensity of which is assigned to Ti–O-P-O-Ti of EMPA was accompanied with increasing the IR peak intensity assigned to MPA. About that, we suggest that the appearance of the Ti–O-P-O-Ti of EMPA by the TiO2 photocatalysis is regarded as acceleration of the hydrolysis of EMPA by the surface OH groups of TiO2. The plausible adsorption structure and the photocatalytic reaction mechanism of EMPA at the surface of TiO2 photocatalyst were elucidated.
Genetically encoded fluorescent proteins (FPs) have been used for metal ion detection. However, their applications are restricted to a limited number of metal ions owing to the lack of available metal-binding proteins or peptides that can be fused to FPs and the difficulty in transforming the binding of metal ions into a change of fluorescent signal. We report herein the use of Mg2+-specific 10–23 or Zn2+-specific 8–17 RNA-cleaving DNAzymes to regulate the expression of FPs as a new class of ratiometric fluorescent sensors for metal ions. Specifically, we demonstrate the use of DNAzymes to suppress the expression of Clover2, a variant of the green FP (GFP), by cleaving the mRNA of Clover2, while the expression of Ruby2, a mutant of the red FP (RFP), is not affected. The Mg2+ or Zn2+ in HeLa cells can be detected using both confocal imaging and flow cytometry. Since a wide variety of metal-specific DNAzymes can be obtained, this method can likely be applied to imaging many other metal ions, expanding the range of the current genetically encoded fluorescent protein-based sensors. 相似文献
Structures of ionic liquids (ILs) 1-decyl-3-methylimidazolium bis(trifluoromethanesulfonyl)azanide ([C10mim][TFSA]) and 1-decyl-dimethylimidazolium bis(trifluoromethanesulfonyl)azanide ([C10(mim)2](TFSA)2) in different-sized mica slits have been investigated using molecular dynamics simulations. Ion density and angular distributions for monocationic IL [C10mim][TFSA] were analysed to elucidate the IL structures under different surface charges and especially their changes in the direction perpendicular to the surfaces. [C10mim][TFSA] formes in bilayers, compatible with existing models of ILs with long alkyl chains. For dicationic IL [C10(mim)2](TFSA)2, cations adjacent to the mica surface tend to stay parallel to the surface with both positively charged rings absorbed. While near the centre of the slit, dications show the weak tendency of orientation distribution, more random than [C10mim]+ ions. Structures of [C10(mim)2](TFSA)2 cannot be described by bilayer models. Additionally, the in-plane arrangement of [C10mim][TFSA] is more ordered when K+ ions completely neutralise the negative charge of the mica surface, and [C10mim]+ ions tend to be located in hexagonal mica lattices with two aluminium atoms in replacement of silicon atoms. [TFSA]? ions are constrained by the neighbouring K+ ions absorbed onto mica lattices. 相似文献
Improving the environmental performance of resins in wood treatment by using renewable chemicals has been a topic of interest for a long time. At the same time, lignin, the second most abundant biomass on earth, is produced in large scale as a side product and mainly used energetically. The use of lignin in wood adhesives or for wood modification has received a lot of scientific attention. Despite this, there are only few lignin-derived wood products commercially available. This review provides a summary of the research on lignin application in wood adhesives, as well as for wood modification. The research on the use of uncleaved lignin and of cleavage products of lignin is reviewed. Finally, the current state of the art of commercialization of lignin-derived wood products is presented. 相似文献
The different contributions of the interfacial capacitance are identified in the case of passive materials or thin protective coatings deposited on the electrode surface. The method is based on a graphical analysis of the EIS results to determine both the passive-film capacitance in the high-frequency domain and the double-layer capacitance in the low-frequency domain. The proposed analysis is shown to be independent of the physicochemical origins of the frequency dispersion of the interfacial capacitances which results, from an analysis point of view of the experimental results, in the use of a constant-phase element However, for a correct evaluation of the thin-film properties such as its thickness, the high-frequency data must be corrected for the double-layer contribution. In particular, it is shown that if the double-layer capacitance gives a frequency-dispersed response, it is necessary to correct the high-frequency part for the double-layer constant-phase elements. This is first demonstrated on synthetic data and then used for the determination of the thickness of thin oxide film formed on Al in neutral pH solution. 相似文献
DNAzymes are a promising platform for metal ion detection, and a few DNAzyme-based sensors have been reported to detect metal ions inside cells. However, these methods required an influx of metal ions to increase their concentrations for detection. To address this major issue, the design of a catalytic hairpin assembly (CHA) reaction to amplify the signal from photocaged Na+-specific DNAzyme to detect endogenous Na+ inside cells is reported. Upon light activation and in the presence of Na+, the NaA43 DNAzyme cleaves its substrate strand and releases a product strand, which becomes an initiator that trigger the subsequent CHA amplification reaction. This strategy allows detection of endogenous Na+ inside cells, which has been demonstrated by both fluorescent imaging of individual cells and flow cytometry of the whole cell population. This method can be generally applied to detect other endogenous metal ions and thus contribute to deeper understanding of the role of metal ions in biological systems. 相似文献
Two novel characterizations of self-decomposable Bernstein functions are provided. The first one is purely analytic, stating that a function \(\varPsi \) is the Bernstein function of a self-decomposable probability law \(\pi \) on the positive half-axis if and only if alternating sums of \(\varPsi \) satisfy certain monotonicity conditions. The second characterization is of probabilistic nature, showing that \(\varPsi \) is a self-decomposable Bernstein function if and only if a related d-variate function \(C_{\psi ,d}\), \(\psi :=\exp (-\varPsi )\), is a d-variate copula for each \(d \ge 2\). A canonical stochastic construction is presented, in which \(\pi \) (respectively \(\varPsi \)) determines the probability law of an exchangeable sequence of random variables \(\{U_k\}_{k\in {\mathbb {N}}}\) such that \((U_1,\ldots ,U_d) \sim C_{\psi ,d}\) for each \(d \ge 2\). The random variables \(\{U_k\}_{k\in {\mathbb {N}}},\) are i.i.d. conditioned on an increasing Sato process whose law is characterized by \(\varPsi \). The probability law of \(\{U_k\}_{k \in {\mathbb {N}}}\) is studied in quite some detail. 相似文献