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Oxidase‐mimicking nanozymes are more desirable than peroxidase‐mimicking ones since H2O2 can be omitted. However, only a few nanomaterials are known for oxidase‐like activities. In this work, we compared the activity of Mn2O3, Mn3O4 and MnO2 and found that Mn2O3 had the highest oxidase activity. Interestingly, the activity of Mn2O3 was even inhibited by H2O2. The oxidase‐like activity of Mn2O3 was not much affected by the presence of proteins such as bovine serum albumin (BSA), but the physisorption of antibodies to Mn2O3 was not strong enough to withstand the displacement by BSA. We then treated Mn2O3 with 3‐aminopropyltriethoxysilane to graft an amine group, which was used to conjugate antibodies using glutaraldehyde as a crosslinker. A one‐step indirect competitive ELISA (icELISA) was developed for the detection of isocarbophos, and an IC50 of 261.7 ng/mL was obtained, comparable with the results of the standard two‐step assay using horseradish peroxidase (HRP)‐labeled antibodies. This assay has the advantage of significant timesaving for rapid detection of large amounts of samples. This work has discovered a highly efficient oxidase‐mimicking nanozyme useful for various nano‐ and analytical applications. [ABSTRACT FROM AUTHOR]

Having the benefits of low cost, excellent stability and tolerance to extreme conditions, nanozymes are a potential alternative of horseradish peroxidase (HRP) or other enzymes for bioanalytical chemistry, especially immunoassays. CeO2 nanoparticles have oxidase-mimicking activity and can avoid the use of unstable H2O2. For robust assays, the effect of proteins on the activity of CeO2 needs to be carefully studied. Herein, we studied the adsorption and desorption of bovine serum albumin (BSA) from CeO2. The CeO2 nanoparticles exhibited a higher protein adsorption capacity compared to the other tested metal oxide nanoparticles. Although the oxidase-like activity of CeO2 was inhibited by BSA, low concentrations of phosphate and fluoride ions boosted the activity of protein-capped CeO2. CeO2 was still active under strong acidic conditions and at high temperature, while HRP lost its activity. For immunoassay development, we covered CeO2 with an amine-modified silane for covalent conjugation to antibodies. A one-step indirect competitive ELISA for fenitrothion was developed, and an IC50 value of 35.6 ng mL−1 and a limit of detection of 2.1 ng mL−1 were obtained. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of different perforation angles (the angle between the perforation direction and the maximum horizontal principal stress which is also called the preferred fracture plane (PFP)) on the fracture initiation and propagation during the hydraulic fracturing of highly deviated well, laboratory experiments of the hydraulic fracturing of the BZ25-1 oilfield had been carried out on the basis of non-dimensional similar criteria by using 400mm3 cement cubes. We built the geometric model of the hydraulic fracturing fractures which considered the influences of the wellbore azimuth (the angle between the wellbore axis and the PFP), the perforation angle and the well deviation. The results showed that: the perforations in the PFP produce plane fracture; the fractures initiate from the perforations at the upper side of the well hole and then turn to the PFP when the perforation angle is 45°; when the well deviation angle and the perforation angle are both larger than 45°, the fracture initiates difficultly from the perforations at the lower side of the well hole, and multi-fractures easily initiate; when the perforation angle is 90°, multi-fractures initiate, such as twisting fracture, plane fracture, horizontal fracture and T-shape fracture, in addition, the fracture cannot initiate from the perforation tunnels; the larger the well deviation angle is, the easier is the multi-fractures initiation. Moreover, it is easier to result in micro-annulus which makes the fractures more complicated during the hydraulic fracturing of highly deviated well when the perforation angle is not along with the PFP. Oriented perforating technology should be applied in highly deviated well to obtain the big single plane fracture. [ABSTRACT FROM AUTHOR]

Profenofos (PFF) is a commonly used organophosphorus insecticide that requires strict monitoring due to its potential environmental, ecological, and human health risks originating from residues in soil and water systems, as well as accumulation in crops. In this study, a novel monoclonal antibody (mAb) targeting PFF was prepared for the first time and investigated the recognition mechanism through molecular simulation. Subsequently, a mAb-based colloidal gold immunochromatographic assay (GICA) was developed for the rapid screening of PFF in fruit and vegetable samples. The mAb exhibited an IC 50 value of 12.9 ng/mL, and limit of detection (LOD) of 4.6 ng/mL, respectively in indirect competitive immunosorbent enzyme-linked immunosorbent assay (ic-ELISA). After optimization, the developed GICA exhibited a visual limit of detection (vLOD) of 20 ng/mL and a quantitative of detection (qLOD) of 5.2 ng/mL, with a linear range from 10.0 to 83.8 ng/mL. Good correlation was observed between the results of GICA and standard Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS) in matrix and recovery test. The developed GICA can be used for rapid sample detection within 15 minutes, which is an excellent tool for screening PFF in foods and environmental samples., Competing Interests: Declaration of Competing Interest ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. ☐ The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:, (Copyright © 2024. Published by Elsevier Ltd.)

Oxidase-mimicking nanozymes are more desirable than peroxidase-mimicking ones since H 2 O 2 can be omitted. However, only a few nanomaterials are known for oxidase-like activities. In this work, we compared the activity of Mn 2 O 3 , Mn 3 O 4 and MnO 2 and found that Mn 2 O 3 had the highest oxidase activity. Interestingly, the activity of Mn 2 O 3 was even inhibited by H 2 O 2 . The oxidase-like activity of Mn 2 O 3 was not much affected by the presence of proteins such as bovine serum albumin (BSA), but the physisorption of antibodies to Mn 2 O 3 was not strong enough to withstand the displacement by BSA. We then treated Mn 2 O 3 with 3-aminopropyltriethoxysilane to graft an amine group, which was used to conjugate antibodies using glutaraldehyde as a crosslinker. A one-step indirect competitive ELISA (icELISA) was developed for the detection of isocarbophos, and an IC 50 of 261.7 ng/mL was obtained, comparable with the results of the standard two-step assay using horseradish peroxidase (HRP)-labeled antibodies. This assay has the advantage of significant timesaving for rapid detection of large amounts of samples. This work has discovered a highly efficient oxidase-mimicking nanozyme useful for various nano- and analytical applications., (© 2021 Wiley-VCH GmbH.)

Having the benefits of low cost, excellent stability and tolerance to extreme conditions, nanozymes are a potential alternative of horseradish peroxidase (HRP) or other enzymes for bioanalytical chemistry, especially immunoassays. CeO 2 nanoparticles have oxidase-mimicking activity and can avoid the use of unstable H 2 O 2 . For robust assays, the effect of proteins on the activity of CeO 2 needs to be carefully studied. Herein, we studied the adsorption and desorption of bovine serum albumin (BSA) from CeO 2 . The CeO 2 nanoparticles exhibited a higher protein adsorption capacity compared to the other tested metal oxide nanoparticles. Although the oxidase-like activity of CeO 2 was inhibited by BSA, low concentrations of phosphate and fluoride ions boosted the activity of protein-capped CeO 2 . CeO 2 was still active under strong acidic conditions and at high temperature, while HRP lost its activity. For immunoassay development, we covered CeO 2 with an amine-modified silane for covalent conjugation to antibodies. A one-step indirect competitive ELISA for fenitrothion was developed, and an IC 50 value of 35.6 ng mL -1 and a limit of detection of 2.1 ng mL -1 were obtained.

Immunoassay for pesticides is an emerging analytical method since it is rapid, efficient, sensitive, and inexpensive. In this study, a recombinant antigen-binding fragment (Fab) against a broad set of O , O -diethyl organophosphorus pesticides (DOPs) was produced and characterized. The κ chain and Fd fragment were amplified via PCR and inserted into the vector pComb3XSS and the soluble Fab on phagemid pComb3XSS was induced by isopropyl β -d-thiogalactoside in E. coli TOP 10F’. SDS-PAGE, Western blotting, and indirect competitive ELISA results indicated that Fab maintained the good characteristics of the parental mAb. To better understand antibody recognition, the three-dimensional (3D) model of Fab was built via homologous modeling and the interaction between Fab and DOPs was studied via molecular docking and dynamics simulations. The model clearly explained the interaction manner of Fab and DOPs, and showed that the Arg-L96 and Arg-H52 were mainly responsible for antibody binding. This work provided a foundation for further mutagenesis of Fab to improve its characteristics.

Cysteine-rich secretory protein 2 (CRISP2) is an important protein in spermatozoa that plays roles in modulating sperm flagellar motility, the acrosome reaction, and gamete fusion. Spermatozoa lacking CRISP2 exhibit low sperm motility and abnormal morphology. However, the molecular mechanisms underlying the reduction of CRISP2 in asthenoteratozoospermia (ATZ) remain unknown. In this study, low expression of CRISP2 protein rather than its mRNA was observed in the ejaculated spermatozoa from ATZ patients as compared with normozoospermic males. Subsequently, bioinformatic prediction, luciferase reporter assays, and microRNA-27a (miR-27a) transfection experiments revealed that miR-27a specifically targets CRISP2 by binding to its 3' untranslated region (3'-UTR), suppressing CRISP2 expression posttranscriptionally. Further evidence was provided by the clinical observation of high miR-27a expression in ejaculated spermatozoa from ATZ patients and a negative correlation between miR-27a expression and CRISP2 protein expression. Finally, a retrospective follow-up study supported that both high miR-27a expression and low CRISP2 protein expression were associated with low progressive sperm motility, abnormal morphology, and infertility. This study demonstrates a novel mechanism responsible for reduced CRISP2 expression in ATZ, which may offer a potential therapeutic target for treating male infertility, or for male contraception.

Objective: To study the effect of reserving articular capsule and traditional total hip replacement for old patients with unstable femoral neck fractures., Methods: From January 2010 to January 2015, one hundred and twenty patients with femoral neck fracture were retrospective review. Among them, sixty patients were treated with total hip arthroplasty reserving articular capsule, the others were treated with traditional total hip arthroplasty without reserving articular capsule. The gender of reserving articular capsule group and traditional group were (male/female) 34/26, 31/29 respectively; the age were (73.4±4.4), (72.3±4.1) years old, respectively. All patients were followed up for six months, the operation time, blood loss, length of stay, incidence of postoperative complications, incidence of postoperative hip dislocation and hip Harris score of the two groups were observed., Results: The operative time of the reserving articular capsule group and traditional group were (95.68±6.90), (93.39±7.90) min ( P >0.05), and the blood loss were (998.78±15.20), (1 000.25±16.80) ml ( P >0.05). The time for hospital stay were (10.74±2.90), (13.25±2.20) days( P <0.05). The Harris scores were 58.53±5.10, 49.38±4.90( P <0.05) at 1 month after operation;91.08±7.50, 90.74±7.10( P >0.05) at 6 months after operation., Conclusions: The method of reserving auricular capsule can not increase the operative time and the blood loss. But it has a favorable effect on decreasing the hospital stay, complication, the rate of early dislocation of the hip joint, improving the function of hip joint., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose.