RESUMO
The chemiluminescence (CL) reaction between ozone and 3,6-dihydroxynaphtha-2,7-disulphonate (DNDS) was found under alkaline conditions. Therefore, a novel CL system for ozone detection was established. The CL signal of the CL system is weak, and the CL signal is enhanced by adding nonionic surfactants. It was found that adding 16.4 g/l Triton X-100 can enhance the CL signal. The CL reagent activated by ultraviolet (UV) light produced a CL signal was nearly 10 times stronger than the CL reagent not activated by UV light; the CL signal was enhanced by adding 8 g/l NaHCO3 to the CL reagent irradiated by UV light. Through the optimization of these test conditions, a high-selectivity, high-sensitivity online detection method for ozone CL was established. The linear range was 0.5-150 ppbv, and the limit of detection (LOD) was 0.092 ppbv (S/N = 3).
Assuntos
Luminescência , Ozônio , Medições Luminescentes/métodos , Indicadores e Reagentes , Limite de DetecçãoRESUMO
A composite concrete column with encased fiber reinforced polymer (FRP) confined concrete cores (EFCCC) is proposed in this paper. The cross-sectional form of the EFCCC column is composed of several orderly arranged FRP confined concrete cores (FCCCs) surrounding a filled core concrete. This novel composite column has several advantages, such as higher compressive capacity, stronger FRP confinement, and ductile response. The compressive experiment is employed to investigate the compressive behavior of the EFCCC column with deferent parameters, such as outside concrete and stirrups. Test results show that the main failure mode of the EFCCC column with and without an outside concrete or stirrups is tensile fracture of the glass fiber reinforced polymer (GFRP) tubes. Compared to a reinforced concrete (RC) column, the strength and ductility of the EFCCC column was obviously improved by 20% and 500%, respectively. A finite element model (FEM) based on the Drucker-Prager (D-P) was developed that can accurately predict the axial compression behavior of the composite column with FRP confined concrete core. The predicted results obtained by using this FEM have excellent agreement with the experimental results.
RESUMO
In this paper, the objective is to immobilize molecularly imprinted polymers (MIPs) onto the surface of magnetic carbon nanoparticles (Fe3O4@SiO2@C) to develop an effective method for the adsorption of zearalenone (ZEN). The prepared products were characterized by FT-IR, SEM, TEM, XRD, VSM, TGA, and BET. The content of zearalenone in corn samples was monitored by HPLC. The results indicate that the particle size of magnetic molecularly imprinted polymers (MMIPs) is approximately 200 nm. The adsorption mechanism of MMIPs was confirmed by static adsorption and dynamic adsorption experiments. The maximum adsorption capacity was 1.56 mg/g, and the adsorption equilibrium was reached within 50 min. The scatchard model showed that MMIPs had two binding sites, a high-affinity binding site and a low-affinity site. Kinetic second-order fitting indicates that MMIPs are mainly through chemisorption. In the actual sample application, the limit of detection (LOD) and limit of quantitation (LOQ) were 0.3 mg/L and 0.9 mg/L, respectively. The recovery of corn with the standard addition of ZEN was 73.6-88.1%, and the relative standard deviation (RSD) was 2.86-5.63%. The results demonstrated that MMIPs possess the advantages of straightforward operation, high precision, and cost-effectiveness, rendering them suitable for rapid ZEN detection.
Assuntos
Carbono , Impressão Molecular , Zearalenona , Zearalenona/química , Adsorção , Carbono/química , Zea mays/química , Nanoestruturas/química , Polímeros/químicaRESUMO
The strong hydrophobicity of the PVDF membrane is prone to contamination that is hard to clean for long-term usage. In this study, hydrophilic and antifouling nanofiber membranes (NMs) were prepared with the hydrophilic polymer PVP and inorganic nanoparticles TiO2NPS. This NM was found to have excellent cleanability and good recyclability. Within 30 minutes, the residual ions could be removed by cleaning with deionized water. In alkaline solutions with the power of hydrogen (PH) ≤10, NM exhibits good alkaline resistance and recycling performance. It was also found, for the first time, that TiO2NPS could enhance the sensitivity of Luminol-NO2 (L-NO2) by 4 times. The detection of NO2 concentration by NM presents an excellent linear relationship with the chemiluminescence reading. This linear relationship would aid quick and convenient detection of NO2 using chemiluminescence.
RESUMO
Diseases caused by novel duck reovirus (NDRV) have brought considerable economic losses to the poultry industry. MicroRNAs (miRNAs) have an impact on virus replication and antiviral immunity. However, the miRNA profile upon NDRV infection in duck embryo fibroblasts (DEFs) remains to be discovered. In this study, small RNA (sRNA) sequencing was performed to decipher the cellular miRNA response to NDRV infection. Based on 26 differentially expressed miRNAs (19 upregulated and 7 downregulated miRNAs) obtained from sequencing data and their target genes predicted by software, GO and KEGG analyses were performed to elucidate the functions of miRNAs in NDRV invasion, replication, and virus spread. "FoxO signaling pathway", "autophagy", and "Toll-like receptor signaling pathway" might participate in NDRV replication as revealed by KEGG enrichment analysis. The miR-155-1 sequence was found to be identical to rno-miR-155-5p and was sharply increased with the progression of NDRV infection. Moreover, NDRV-induced miR-155-1 could act as a positive factor for virus replication in DEFs, which inhibited type I interferon (IFN-I) production. Luciferase assay confirmed that miR-155-1 disturbed the abundance of suppressor of cytokine signaling (SOCS) 5 by targeting 3'-UTR. SOCS5, which is linked to increased IRF7 expression, restricts IFN expression and promotes NDRV replication in DEFs. Therefore, this study proposed that miR-155-1 was used by NDRV to restrict SOCS5 expression, attenuating the production of IFN-I and creating a favorable environment for virus replication.