Herein, a novel and sensitive sandwich-type electrochemical immunosensor was fabricated for quantitative monitoring of prostate specific antigen (PSA). The sulfo group functionalized multi-walled ...carbon nanotubes (MWCNTs-SO3H) were used as substrate material to increase the specific surface area and enhance the conductivity of the glassy carbon electrode. Gold nanoparticles (Au NPs) were introduced to enhance the load capacity of the substrate material for primary antibodies (Ab1) and accelerate the electron transfer on the electrode interface. The mesoporous core-shell Pd@Pt nanoparticle loaded by amino group functionalized graphene (M-Pd@Pt/NH2-GS) with high specific surface area, high indexed facets, and good biocompatibility was not only as the carriers of secondary antibodies (Ab2) but also catalyzed the reduction of hydrogen peroxide (H2O2), which effectually amplified the current signal in detection of PSA. The as-proposed immunosensor exhibited high sensitivity and stability on the detection of PSA. A linear relationship between current signals and the concentrations of PSA was obtained in the range from 10fg/mL to 50ng/mL and the detection limit of PSA was 3.3fg/mL (signal-to-noise ratio of 3). Furthermore, the as-proposed immunosensor showed excellent performance in detection of human serum samples. The results suggest that the proposed immunosensor will be promising in the diagnostics application for accurately quantitative detection of PSA.
•Au NPs hybrid MWCNTs-SO3H was first used in the biosensor as substrate material.•A novel M-Pd@Pt was first used as a signal amplifier in the immunosensor.•The M-Pd@Pt/NH2-GS was applied as a label in the immunosensor at the first time.•The novel immunosensor exhibited excellent sensitivity, stability and selectivity.
Oximes are an easily prepared and transformed unit, which are widely used in organic synthesis. The oximes, including oxime ethers and esters, could realize various transformations, such as C–H bond ...activation, Heck‐type reactions, N–O bond cleavage/C–N bond formation, O–H bond cleavage and couplings. However, there is no a comprehensive review on this subject. Herein, we summarize the recent advances over the past 15 years in transition metal‐catalyzed reactions involving oximes, focusing on the reaction scope, limitations and mechanisms.
An ultrasensitive sandwich-type electrochemical immunosensor was designed by using gold nanoparticles (Au NPs) as the substrate material and microporous carbon spheres (CS) loading silver ...nanoparticles (Ag NPs) spaced Hemin/reduced graphene oxide (Hemin/rGO) porous composite materials (Ag NPs@CS-Hemin/rGO) as the detection antibodies (Ab2) label for detecting carcinoembryonic antigen (CEA). The Au NPs with good electrical conductivity and biocompatibility could accelerate the electron transfer on the electrode interface and enhance the load capacity of capture antibodies (Ab1). Hemin is peroxidase-like substance which has excellent catalytic ability for H2O2 reduction but easy to molecular aggregation and oxidative self-destruction. Reduced graphene oxide (rGO) is a good supporting material for Hemin to mitigate this disadvantage. CS loading Ag NPs (Ag NPs@CS) as the spacer inserts into Hemin/rGO sheet can overcome the irreversible stacking of rGO, and form complex porous structure which exposes more active sites of Hemin. Moreover, Ag NPs loaded on CS also has catalytic ability for H2O2 reduction. Thus the Ag NPs@CS-Hemin/rGO used as the Ab2 label has a large working surface area and high utilization rate, which heightens the catalytic ability for H2O2 reduction to amplify the current signal effectually. The current signal and the logarithm of CEA concentration presented a wide linear response range of 20 fg/mL to 200 ng/mL, and the detection limit of CEA was 6.7 fg/mL. Furthermore, the designed immunosensor exhibited a good reproducibility, selectivity and stability, which confirms a broad development prospect when applying it in early clinical detection.
•The immunosensor exhibits a broad detection range and low detection limit for CEA.•The Ag NPs@CS-Hemin/rGO was first applied as an Ab2 label to amplify current signal.•Use Ag NPs@CS as the spacer inserted into Hemin/rGO to form porous structure.•The immunosensor shows a good prospect in early clinical detection.
A sensitive sandwich-type electrochemical immunosensor for the detection of hepatitis B e antigen (HBeAg) was successfully developed based on the gold@palladium nanoparticles (Au@Pd NPs) loaded by ...molybdenum disulfide functionalized multiwalled carbon nanotubes (Au@Pd/MoS2@MWCNTs). The resultant nanocomposites not only possessed high specific surface area and good biocompatibility, but also exhibited excellent electro-catalytical property. Au NPs functionalized porous graphene oxide (p-GO@Au) were used as sensing platforms and primary antibodies carriers, which can accelerate the electron transfer and improve the load capacity of primary antibodies (Ab1), improving the sensitivity of the immunosensor. Under optimal conditions, the designed immunosensor could detect target HBeAg concentration in the range from 0.1pg/mL to 500pg/mL, with a low detection limit of 26fg/mL (S/N = 3) for HBeAg. Additionally, the designed immunosensor showed excellent specificity, good reproducibility and acceptable stability. The satisfactory results in analysis of human serum samples indicated that it had potential application in clinical monitoring of tumor markers.
•Using the p-GO@Au as sensing platform increased the loading of primary antibodies.•Dandelion-like Au@Pd nanoparticles were used in immunosensor.•Au@Pd/MoS2@MWCNTs has better electrocatalytic activity towards reduction of H2O2.•The sandwich-type immunosensor showed desired sensitivity and stability for HBeAg detection.
To better understand the application of diatomite as an adsorbent for the removal of Pb(II) from heavy metal-contaminated water, in this paper, diatomite was used to adsorb Pb(II) from aqueous ...solution under various conditions. The results demonstrated that the adsorption of Pb(II) was strongly dependent on ionic strength at pH
<
7.0, outer-sphere surface complexation or ion exchange may be the main adsorption mechanism of Pb(II) on diatomite at low pH values. No drastic difference of Pb(II) adsorption was observed at pH
>
7.0, and the adsorption at high pH values was mainly dominated via inner-sphere surface complexation. The presence of HA/FA showed great influence on Pb(II) adsorption on diatomite. The adsorption of Pb(II) on diatomite was dependent on foreign ions (herein K
+, Na
+, ClO
4
−, NO
3
− and Cl
−) in solution at pH
<
8.0, and was independent of foreign ions at pH
>
8.0. The thermodynamic parameters (i.e., Δ
H°, Δ
S°, Δ
G°) were evaluated from the temperature dependent adsorption isotherms. The results indicated that the adsorption process of Pb(II) on diatomite was spontaneous and endothermic in nature.
Bentonite has been studied extensively because of its strong adsorption and complexation ability. In this work, GMZ bentonite (China) was characterized by using acid–base titration, XRD and FTIR in ...detail. Removal of Pb(II) from aqueous solution by adsorption onto Na-bentonite was investigated under ambient conditions as a function of shaking time, pH, ionic strength, Na-bentonite content and temperature using batch technique. The kinetic adsorption was described by the pseudo-second-order rate equation well. The adsorption of Pb(II) on Na-bentonite was strongly dependent on pH. The Langmuir model fitted the adsorption isotherm very well. The thermodynamic parameters (Δ
H
0, Δ
S
0 and Δ
G
0) calculated from the temperature dependent adsorption isotherms suggested that the adsorption of Pb(II) was endothermic and spontaneous process. At low pH, the adsorption of Pb(II) was dominated by outer-sphere surface complexation and ion exchange with Na
+/H
+ on Na-bentonite surfaces, whereas inner-sphere surface complexation was the main adsorption mechanism at high pH.
•The m-PdPtCu was first used as the label of secondary antibodies in immunosensor.•The m-PdPtCu showed an excellent performance in signal amplification.•The immunosensor enabled highly sensitive and ...selective detection of PSA.•The designed immunosensor is promising in early clinical diagnosis of biomarkers.
In this work, the gold nanoparticles (Au NPs) substrate and the prepared mesoporous trimetallic PdPtCu nanospheres (m-PdPtCu) as the label of secondary antibodies (Ab2, Ab2 labeled probe) were used as the basis for fabricating a highly sensitive immunosensor to detect trace amount of prostate specific antigen (PSA) in human serum. The Au NPs can provide a suitable microenvironment for immobilizing primary antibodies (Ab1) and accelerate the electron transfer on the electrode interface due to the good biocompatibility and conductivity. The sensitivity of immunosensor was greatly amplified by the designed novel Ab2 labeled probe, which can be attributed to the m-PdPtCu with mesoporous structure not only can provide high specific surface area, but also offer abundant catalytically active sites and accessible pores for reactants. Under the optimal conditions, a linear relationship between current responses and the logarithm of the PSA concentrations were obtained in the wide range of 10 fg mL−1–100 ng mL−1 and the detection limit was 3.3 fg mL−1. Remarkably, the detection result of PSA in real human serum samples by the immunosensor is well in correlation with commercial ELISA, which confirms that the immunosensor is promising in early clinical detection of biomarkers.
When the correlation of wind power output among wind farms is not considered, the integrated stochastic characteristics of wind power will not be captured accurately. Using this inaccurate feature ...may lead to an impractical even a failing result of unit commitment (UC). Therefore, this paper proposes a multiple correlations model for wind power forecast errors (WPFEs), and to capture this multiple correlation feature in UC problem, a two‐stage chance‐constrained interval UC (CIUC) model is proposed. First, an analytical expression of multiple correlations, including spatial, temporal and conditional correlations, is presented to improve the description accuracy of stochastic WPFEs. To strike a balance between risk and operational cost, a chance‐constrained decision method is developed to optimize the time‐varying interval of wind power output in the first stage. Subsequently, an interval UC model is established to determine the optimal operational schedule in the second stage. Finally, the proposed CIUC model is solved using a solution strategy that combines column‐and‐constraint generation and sample average approximation. The effectiveness and practicality of the proposed method are verified via the numerical results for IEEE 39‐bus and 118‐bus systems.
In this study, a core-and-cladding-integrated fibre Bragg grating (FBG) using an 800-nm infrared-radiation femtosecond pulsed laser via line-by-line inscription focused through polyimide fibre ...coating is developed. For the proposed FBG, each inscription line is 10 µm and the grating length is 2000 µm, realising first-order 1559.8- and 1565-nm dual-wavelength FBG simultaneously, with an inscription period of 541 nm. In the experiment, an 800-nm femtosecond laser with 1-kHz repeat frequency is used as the inscription laser, focused by a 63× oil lens. The grating area covers both the fibre core and the cladding through the polyimide coating, and the reflectivity of core and cladding FBG are 96.3% and 78.5%, respectively. The FBG stretching upload and unload characteristics are measured for a 0-35 µm stretching length. The wavelength shifts of the two peaks are obvious with sensitivities of 1.8 pm/µm.
Electrophilic Amination The task of realizing selective assembly of amines from readily available precursors has become a prominent objective in organic chemistry. The importance of C−N bond ...construction by application of O‐benzoylhydroxylamines in transition‐metal‐catalyzed electrophilic amination has led to the rapid development of this field. In their Review article on page 2481 ff., Q. Liu, H. Liu and colleagues describe the recent advances of O‐benzoylhydroxylamines involved in electrophilic amination catalyzed by transition metals. Several pioneering studies and some of the relevant mechanisms are discussed.
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