Preparation of surface molecular imprinting fluorescent sensor based on magnetic porous silica for sensitive and selective determination of catechol.

A magnetic fluorescent molecularly imprinted sensor was successfully prepared and implemented to determine catechol (CT). Fe3O4 nanoparticles were synthesized by the solvothermal technique and mesoporous Fe3O4@SiO2@mSiO2 imprinted carriers were prepared by coating nonporous and mesoporous SiO2 shells on the surface of the Fe3O4 subsequently. The magnetic surface molecularly imprinted fluorescent sensor was created after the magnetic mesoporous carriers were modified with γ-methacryloxyl propyl trimethoxy silane to introduce double bonds on the surface of the carries and the polymerization was carried out in the presence of CT and fluorescent monomers. The magnetic mesoporous carriers were modified with γ-methacryloxyl propyl trimethoxy silane and double bonds were introduced on the surface of the carriers. After CT binding with the molecularly imprinted polymers (MIPs), the fluorescent intensity of the molecularly imprinted polymers (Ex = 400 nm, Em = 523 nm) increased significantly. The fluorescent intensity ratio (F/F0) of the sensor demonstrated a favorable linear correlation with the concentration of CT between 5 and 50 µM with a detection limit of 0.025 µM. Furthermore, the sensor was successfully applied to determine CT in actual samples with recoveries of 96.4-105% and relative standard deviations were lower than 3.5%. The results indicated that the research of our present work provided an efficient approach for swiftly and accurately determining organic pollutant in water.

Preparation of molecularly imprinted ratiometric fluorescence sensor for visual detection of tetrabromobisphenol A in water samples.

A sensitive molecularly imprinted ratiometric fluorescence sensor was constructed for the first time to visually detect tetrabromobisphenol A (TBBPA). The blue fluorescent carbon quantum dots (CQDs) were coated with SiO2 through the reverse microemulsion method to obtain a stable internal reference signal CQDs@SiO2. The ratiometric fluorescence sensor was finally prepared using red fluorescent CdTe QDs as the response signal in the presence of CQDs@SiO2. When the molecularly imprinted polymers were combined with TBBPA, the fluorescence of CdTe QDs (Ex = 365 nm, Em = 665 nm) was rapidly quenched, while that of CQDs (Ex = 365 nm, Em = 441 nm) remained stable, resulting in a noticeable fluorescence color change. Moreover, the fluorescence intensity ratio (I665/I441)0/(I665/I441) of the sensor showed a linear response to TBBPA in the concentration range 0.1 to 10 µM with a low detection limit of 3.8 nM. The prepared sensor was successfully applied to detect TBBPA in water samples. The recoveries were in the range 98.2-103%, with relative standard deviations lower than 2.5%. Furthermore, a fluorescent test strip for visual monitoring of TBBPA was constructed to streamline the procedure. The excellent results demonstrate that the prepared test strip has a broad prospect for the offline detection of pollutants.

Enhanced Electrochemical Performance of PEO-Based Composite Polymer Electrolyte with Single-Ion Conducting Polymer Grafted SiO2 Nanoparticles.

In order to enhance the electrochemical performance and mechanical properties of poly(ethylene oxide) (PEO)-based solid polymer electrolytes, composite solid electrolytes (CSE) composed of single-ion conducting polymer-modified SiO2, PEO and lithium salt were prepared and used in lithium-ion batteries in this work. The pyridyl disulfide terminated polymer (py-ss-PLiSSPSI) is synthesized through RAFT polymerization, then grafted onto SiO2 via thiol-disulfide exchange reaction between SiO2-SH and py-ss-PLiSSPSI. The chemical structure, surface morphology and elemental distribution of the as-prepared polymer and the PLiSSPSI-g-SiO2 nanoparticles have been investigated. Moreover, CSEs containing 2, 6, and 10 wt% PLiSSPSI-g-SiO2 nanoparticles (PLi-g-SiCSEs) are fabricated and characterized. The compatibility of the PLiSSPSI-g-SiO2 nanoparticles and the PEO can be effectively improved owing to the excellent dispersibility of the functionalized nanoparticles in the polymer matrix, which promotes the comprehensive performances of PLi-g-SiCSEs. The PLi-g-SiCSE-6 exhibits the highest ionic conductivity (0.22 mS·cm-1) at 60 °C, a large tLi+ of 0.77, a wider electrochemical window of 5.6 V and a rather good lithium plating/stripping performance at 60 °C, as well as superior mechanical properties. Hence, the CSEs containing single-ion conducting polymer modified nanoparticles are promising candidates for all-solid-state lithium-ion batteries.

Impact of serum uric acid levels on the clinical prognosis and severity of coronary artery disease in patients with acute coronary syndrome and hypertension after percutaneous coronary intervention: a prospective cohort study.

OBJECTIVE: The impact of serum uric acid (sUA) levels on the clinical prognosis and severity of coronary artery disease in patients with acute coronary syndrome (ACS) and hypertension after percutaneous coronary intervention (PCI) is not fully clear. This study aimed to assess the association among sUA levels, clinical prognosis and severity of coronary artery disease in patients with ACS and hypertension after PCI. DESIGN: In this prospective cohort study, we followed-up patients with ACS and hypertension after PCI for 1 year to explore the risk factors for 1 year total major adverse cardiovascular events (MACEs) and multivessel coronary artery disease, the dose-effect relationship among sUA levels, MACEs and severity of coronary artery disease and correlation between sUA levels and severity of coronary artery disease (Gensini score). SETTING/PATIENTS: Several Chinese internists followed-up 422 patients who were diagnosed with ACS and hypertension after PCI in a large tertiary hospital of Qingdao during the period from 1 June 2019 to 1 December 2019. OUTCOME MEASURES: One-year follow-up MACEs results and coronary angiography results. RESULTS: In the coronary angiography results, multivessel coronary artery disease (28.5% vs 21.4%, p=0.006) and non-culprit lesion vascular occlusion (11.7% vs 5.3%, p=0.042) were more common in the hyperuricaemia group, and the Gensini score (26.69±13.46 vs 17.66±10.57, p<0.001) was also higher. In the results of 1-year MACEs, the incidence of all-cause mortality (3.5% vs 2.5%, p=0.037), PCI or coronary artery bypass grafting therapy due to myocardial infarction or angina pectoris (15.1% vs 7.6%, p=0.027), medication conservative therapy in hospital due to myocardial infarction or angina pectoris (12.9% vs 6.7%, p=0.041) and total MACEs (31.8% vs 16.9%, p=0.001) were higher in patients with hyperuricaemia. Univariate and multivariate logistic regression analysis models showed that hyperuricaemia was still an independent risk factor for total MACEs within 1 year (OR=2.618, 95% CI 1.656 to 4.139, p<0.001; OR=1.920, 95% CI 1.158 to 3.183, p=0.011, respectively) and multivessel coronary artery disease (OR=2.140, 95% CI 1.371 to 3.342, p=0.001; OR=1.688, 95% CI 1.051 to 2.710, p=0.030, respectively) after adjusting for confounding factors. The severity of coronary artery disease (non-culprit lesion vascular occlusion (4.7% vs 8.4% vs 9.6% vs 16.2%, p=0.041); multivessel coronary artery disease (17.9% vs 22.4% vs 29.8% vs 35.2%, p=0.022); Gensini score (16.96±10.35 vs 19.31±10.63 vs 26.12±11.48 vs 33.33±14.01, p<0.001)) and the incidence of total MACEs (13.2% vs 14.2% vs 34.6% vs 41%, p<0.001) increased significantly with the sUA levels increasing. Further, the Gensini score was positively correlated with uric acid levels (r=0.515, p<0.001). CONCLUSIONS: Hyperuricaemia is an independent risk factor for 1-year total MACEs and multivessel coronary artery disease in patients with ACS and hypertension after PCI.

Optimization of Waterborne Poly(Urethane-Acrylate) Nanoemulsions Based on Cationic Polymerizable Macrosurfactants with Different Hydrophobic Side Chain Length.

In situ surfactant-free emulsion polymerization can help avoid the utilization of harmful co-solvents and surfactants in the preparation of waterborne poly(urethane-acrylate) (WPUA) nanoemulsion, but the solid content is extremely limited, which will affect the drying rate and film-forming properties. The utilization of polymerizable macrosurfactants can overcome the above problems. However, the research on cationic polymerizable macrosurfactants is extremely scarce. In this work, cationic dimethylaminoethyl methacrylate-b-alkyl methacrylates block copolymers (PDM-b-PRMA) with terminal double bonds and different hydrophobic side chain (HSC) lengths were fabricated via catalytic chain transfer polymerization (CCTP). HSC length of PDM-b-PRMA played an important role in the phase inversion, morphology, rheological behavior of WPUA nanoemulsions, as well as the comprehensive performance of WPUA/PDM-b-PRMA films. Polymerizable PDM-b-PBMA macrosurfactant had smaller molecular weight, lower surface tension and colloidal size than the random copolymer (PDM-co-PBMA) by traditional free radical polymerization. It was easy for PDM-b-PRMA to orientedly assemble at the oil/water interface and provide better emulsifying ability when the carbon number of HSC was four. Compared with WPUA/PDM-co-PBMA, WPUA/PDM-b-PBMA had a smaller particle size, stability and better film-forming properties. This work elucidated the mechanisms of HSC length in the fabrication of cationic PDM-b-PRMA and provides a novel strategy to prepare cationic WPUA of high performance.

Preparation of novel magnetic molecular imprinted polymers nanospheres via reversible addition - fragmentation chain transfer polymerization for selective and efficient determination of tetrabromobisphenol A.

A well-defined molecularly imprinted polymer nanospheres with excellent specific recognition ability was prepared on Fe3O4 nanoparticles via the combination of click chemistry and surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization and using Tetrabromobisphenol A as template. Concretely, Fe3O4 nanoparticles were prepared by solvothermal method and then modified by 4-vinylbenylchloride through distillation-precipitation, which makes azide groups easily introduced on the surface of magnetic nanoparticles to form the relatively large amount of benzyl chloride groups. With high efficiency, alkyne terminated RAFT chain transfer agent were then immobilized onto the surface of Fe3O4 by means of click chemistry, which is Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The highly uniform imprinted thin film was finally fabricated on the surface of RAFT agent modified Fe3O4 nanoparticles. The binding results demonstrated that as-prepared imprinted beads exhibited remarkable molecular imprinting effects to the template molecule, fast rebinding kinetics and an excellent selectivity to compounds with similar configuration.

Exceptional polarization structures near the C-lines in diffracted near fields.

We study the polarization structures in the vicinity of C-lines in the near fields diffracted from a pair of small holes. We find that, when the incident light is circularly polarized, both the true C-lines and the structures near them are controlled only by the longitudinal component. Furthermore, we find that all the existing singular lines of circular polarization have the winding number ±1, which is very different than the usual numbers ±1/2, and the structure of major axes of the polarization ellipses surrounding these lines are shown to form structures different than the Möbius strip type. All these features prove to be stable upon small changes of shapes or positions of the apertures. However, C-lines with a unit winding number split into two C-lines of half-winding numbers when the incident light is elliptically polarized light.

Novel magnetic porous carbon spheres derived from chelating resin as a heterogeneous Fenton catalyst for the removal of methylene blue from aqueous solution.

Porous magnetic carbon spheres (MCS) were prepared from carbonized chelating resin composites derived from ethylenediaminetetraacetic acid-modified macroporous polystyrene (PS-EDTA) resin, and then loaded with iron composites via ion exchange. The resulting composites were characterized for this study using X-ray diffraction, MÖssbauer spectroscopy, and Raman spectroscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area method, scanning electron microscopy, and vibrating sample magnetometry. The porous magnetic carbon spheres were then used, in the existence of H2O2 and NH2OH, with a view to remove methylene blue from the aqueous solution by catalyze a heterogeneous Fenton reaction. Results indicated excellent removal rates and removal efficiency for this catalytic system. Optimal degradation was achieved (nearly 100% within 10 min) using initial concentrations of 5 mmol H2O2 L(-1), 2.5 mmol L(-1) NH2OH and 40 mg L(-1) methylene blue. The catalyst retained its activity after six reuses, indicating strong stability and reusability. Porosity of the catalyst contributed to its high activity, suggesting its potential application for the industrial treatment of wastewater.

[Endpoint Temperature Prediction of the Basic Oxygen Furnace Based on the Flame Temperature Measurement at the Converter Mouth].

In the basic oxygen steelmaking process, the endpoint temperature of the molten steel is one of the key factors whether the molten steel is qualified for tapping. Currently, it mainly relies on the experienced operators to control the endpoint temperature of the molten steel, and the prediction precision may vary among different operators. In order to realize the effectively end-point steel temperature prediction of the basic oxygen furnace as well as to meet the requirement of different sizes of the converter mouth, a new method based on the flame temperature measurement at the converter mouth was proposed in this paper. Firstly, a fiber-optic spectrometer system in the visible and near infrared spectral range was designed which can real-timely and effectively realize the collection of the flame radiation information at the converter mouth. Secondly, in consideration of the actual temperature of the flame and the distance between the converter and the designed system, an improved calibration method instead of the halogen lamp was adopted, and the two-color method was employed for the flame temperature measurement. Then a regression model based on the support vector machine was built with the flame temperature and several other parameters of the steel-making process as the input variables of the model. Verification experiment was carried out on 68 industrial data collected in the steel-making workshop. The results show that the prediction accuracy of this method is superior to the experienced operators, and close to the sub-lance based method. As a result, the proposed method can provide a feasible and effective solution to the end-point steel temperature prediction for those small-sized and medium-sized converters.

Preparation and characterization of magnetic porous carbon microspheres for removal of methylene blue by a heterogeneous Fenton reaction.

High-specific-surface-area magnetic porous carbon microspheres (MPCMSs) were fabricated by annealing Fe(2+)-treated porous polystyrene (PS) microspheres, which were prepared using a two-step seed emulsion polymerization process. The resulting porous microspheres were then sulfonated, and Fe(2+) was loaded by ion exchange, followed by annealing at 250 °C for 1 h under an ambient atmosphere to obtain the PS-250 composite. The MPCMS-500 and MPCMS-800 composites were obtained by annealing PS-250 at 500 and 800 °C for 1 h, respectively. The iron oxide in MPCMS-500 mainly existed in the form of Fe3O4, which was concluded by characterization. The MPCMS-500 carbon microspheres were used as catalysts in heterogeneous Fenton reactions to remove methylene blue (MB) from wastewater with the help of H2O2 and NH2OH. The results indicated that this catalytic system has a good performance in terms of removal of MB; it could remove 40 mg L(-1) of MB within 40 min. After the reaction, the catalyst was conveniently separated from the media within several seconds using an external magnetic field, and the catalytic activity was still viable even after 10 removal cycles. The good catalytic performance of the composites could be attributed to synergy between the functions of the porous carbon support and the Fe3O4 nanoparticles embedded in the carrier. This work indicates that porous carbon spheres provide good support for the development of a highly efficient heterogeneous Fenton catalyst useful for environmental pollution cleanup.

Development of carbon nanotubes/CoFe2O4 magnetic hybrid material for removal of tetrabromobisphenol A and Pb(II).

Multi-walled carbon nanotubes (MWCNTs) coated with magnetic amino-modified CoFe2O4 (CoFe2O4-NH2) nanoparticles (denoted as MNP) were prepared via a simple one-pot polyol method. The MNP composite was further modified with chitosan (CTS) to obtain a chitosan-functionalized MWCNT/CoFe2O4-NH2 hybrid material (MNP-CTS). The obtained hybrid materials were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectrogram (FT-IR) Analysis and X-ray Photoelectron Spectroscopy (XPS) Analysis, Vibrating Sample Magnetometer (VSM) Analysis and the Brunauer-Emmett-Teller (BET) surface area method, respectively. The composites were tested as adsorbents for tetrabromobisphenol A (TBBPA) and Pb(II), and were investigated using a pseudo-second-order model. The adsorption of TBBPA was well represented by the Freundlich isotherm; the Langmuir model better described Pb(II) absorption. MNP-CTS adsorbed both TBBPA and Pb(II) (maximum adsorption capacities of 42.48 and 140.1mgg(-1), respectively) better than did MNP without CTS. Magnetic composite particles with adsorbed TBBPA and Pb(II) could be regenerated using 0.2M NaOH solution and were separable from liquid media using a magnetic field.