Preparation and Characterization of Chitosan/Kaolin/FeO Magnetic Microspheres and Their Application for the Removal of Ciprofloxacin

In this study, a magnetically separable adsorbent [chitosan (CTS)/kaolin/Fe 3 O 4 magnetic microspheres] was prepared by emulsion crosslinking. The prepared microspheres were characterized by Fourier transform infrared spectroscopic analysis, vibrating sample magnetometry, X-ray diffraction, transmission electron microscopy, energy-dispersive spectrometry, thermogravimetric analysis and scanning electron microscopy. The synthesized microspheres were used as adsorbents for the removal of ciprofloxacin (CIP) from an aqueous solution. Adsorption of CIP from the aqueous solution was investigated in terms of adsorbent dose, initial pH (pH 0 ) and initial concentration. The optimal pH 0 for CIP adsorption was found to be 6. Highest adsorption capacity was achieved with an adsorbent dose of 15 mg. The adsorption kinetics were well described by the pseudo-second-order equation and the adsorption isotherms were fitted to the Langmuir model. Reusability experiments using CTS/kaolin/Fe 3 O 4 magnetic microspheres showed that the adsorption capacity of these microspheres had no observable deterioration in performance even after four repeated cycles. Results of the adsorption–desorption experiments suggest that CTS/kaolin/Fe 3 O 4 microspheres can be used as promising adsorbents for removing CIP from wastewater

Molecularly Imprinted Fluorescent Test Strip for Direct, Rapid, and Visual Dopamine Detection in Tiny Amount of Biofluid

Paper-based assays for detection of physiologically important species are needed in medical theranostics owning to their superiorities in point of care testing, daily monitoring, and even visual readout by using chromogenic materials. In this work, a facile test strip is developed for visual detection of a neurotransmitter dopamine (DA) based on dual-emission fluorescent molecularly imprinted polymer nanoparticles (DE-MIPs). The DE-MIPs, featured with tailor-made DA affinity and good anti-interference, exhibit DA concentration-dependent fluorescent colors, due to the variable ratios of dual-emission fluorescence caused by DA binding and quenching. By facile coating DE-MIPs on a filter paper, the DA test strips are obtained. The resultant test strip, like the simplicity of a pH test paper, shows the potential for directly visual detection of DA levels just by dripping a tiny amount of biofluid sample on it. The test result of real serum samples demonstrates that the DA strip enables to visually and semiquantitatively detect DA within 3 min by using only 10 microL of serum samples and with a low detection limit ((100-150) x 10(-9) m) by naked eye. This work thus offers a facile and efficient strategy for rapid, visual, and on-site detection of biofluids in clinic

A Comparative Study of Equivalent Circuit Models for Electro-Chemical Impedance Spectroscopy Analysis of Proton Exchange Membrane Fuel Cells

Electrochemical impedance spectroscopy is one of the important tools for the performance analysis and diagnosis of proton exchange membrane fuel cells. The equivalent circuit model is an effective method for electrochemical impedance spectroscopy resolution. In this paper, four typical equivalent circuit models are selected to comprehensively compare and analyze the difference in the fitting results of the models for the electrochemical impedance spectroscopy under different working conditions (inlet pressure, stoichiometry, and humidity) from the perspective of the fitting accuracy, change trend of the model parameters, and the goodness of fit. The results show that the fitting accuracy of the model with the Warburg element is the best for all under each working condition. When considering the goodness of fit, the model with constant phase components is the best choice for fitting electrochemical impedance spectroscopy under different inlet pressure and air stoichiometry. However, under different air humidity, the model with the Warburg element is best. This work can help to promote the development of internal state analysis, estimation, and diagnosis of the fuel cell based on the equivalent circuit modeling of electrochemical impedance spectroscopy

Performance of Poly(Styrene—Divinylbenzene) Magnetic Porous Microspheres Prepared by Suspension Polymerization for the Adsorption of 2, 4-Dichlorophenol and 2, 6-Dichlorophenol from Aqueous Solutions

Poly(styrene–divinylbenzene)/Fe 3 O 4 (Fe 3 O 4 @St–DVB) magnetic porous polymer microspheres based on suspension polymerization were prepared for adsorption of 2, 4-dichlorophenol (2, 4-DCP) and 2, 6-dichlorophenol (2, 6-DCP) from aqueous solution. The as-prepared product was characterized by Fourier transform infrared spectroscopy, Raman, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, differential thermal analysis and elemental analysis. The results showed that the composite material has both porous and magnetic characteristics, which aid in faster separation and increase in adsorption capacity. The adsorption performance of the Fe 3 O 4 @(St–DVB) magnetic porous microspheres was manifested by batch mode adsorption experiments with respect to pH, initial concentration, contact time and temperature. The adsorbent was found to be sensitive to changes in pH, and the adsorption capacity of 2, 4-DCP is higher than that of 2, 6-DCP. The kinetics experimental data fitted well with the pseudo-second-order model, as three steps belonged to the pseudo-second-order adsorption process. The adsorption isotherms were also described by the Langmuir and Freundlich isotherm models, respectively. It was found that the Langmuir isotherm model fitted the equilibrium data superior to the Freundlich model. Thermodynamic parameters were calculated by the Gibbs free energy function, confirming that adsorption process was spontaneous and endothermic. In addition, the reusability performance of the Fe 3 O 4 @(St–DVB) magnetic porous microspheres was demonstrated by four repeated cycles

Novel Graphene Oxide–Confined Nanospace Directed Synthesis of Glucose-Based Porous Carbon Nanosheets with Enhanced Adsorption Performance

Glucose-based porous carbon nanosheets (GPCNS) were synthesized by an integrated graphene oxide–confined nanospace directed KOH-activated process and were applied as adsorbent for efficient removal of sulfamethazine (SMZ). The effects of GO dosage on the structure, specific surface area, and adsorption capacity of GPCNS-<i>x</i> were investigated. The highest SMZ uptake of 820.27 mg g^–1 (298 K) was achieved in glucose-based porous carbon nanosheets inherited from using 1% GO relative to glucose (GPCNS-1). Also, the adsorption isotherms, thermodynamics, and kinetics of SMZ onto GPCNS-1 were studied in detail. In addition, the effects of ionic strength and solution pH on the adsorption capacity of GPCNS-1 were also investigated, indicating good environmental tolerance of GPCNS-1. Furthermore, regeneration experiments showed that GPCNS-1 has good reproducibility and durability. We believe that these graphene oxide–confined nanospace directed KOH-activated process biomass-based carbon nanosheets are highly promising as absorbents in the field of environmental protection

Silencing of APE1 Enhances Sensitivity of Human Hepatocellular Carcinoma Cells to Radiotherapy <em>In Vitro</em> and in a Xenograft Model

<div><p>Resistance to radiotherapy is a key limitation for the treatment of human hepatocellular carcinoma (HCC). To overcome this problem, we investigated the correlation between radioresistance and the human apurinic/apyrimidinic endonuclease (APE1), a bifunctional protein, which plays an important role in DNA repair and redox regulation activity of transcription factors. In the present study, we examined the radiosensitivity profiles of three human HCC cell lines, HepG2, Hep3B, and MHCC97L, using the adenoviral vector Ad5/F35-mediated APE1 siRNA (Ad5/F35-siAPE1). The p53 mutant cell lines MHCC97L showed radioresistance, compared with HepG2 and Hep3B cells. APE1 was strongly expressed in MHCC97L cells and was induced by irradiation in a dose-dependent manner, and Ad5/F35-siAPE1 effectively inhibited irradiation-induced APE1 and p53 expression. Moreover, silencing of APE1 significantly potentiated the growth inhibition and apoptosis induction by irradiation in all tested human HCC cell lines. In addition, Ad5/F35-siAPE1 significantly enhanced inhibition of tumor growth and potentiated cell apoptosis by irradiation both in HepG2 and MHCC97L xenografts. In conclusion, down regulation of APE1 could enhance sensitivity of human HCC cells to radiotherapy <em>in vitro</em> and <em>in vivo</em>.</p> </div

Ad5/F35-siAPE1 enhances cell killing following irradiation in human HCC cell lines.

<p>Cells were infected with Ad5/F35-EGFP or Ad5/F35-siAPE1. At 48 h post-infection, samples were treated with different doses of irradiation. Cell survival following exposure to various doses of irradiation was evaluated by MTT (A) and colony formation assay (B). Each data point represents the mean±standard deviation of three independent determinations. Significant differences existed at all doses levels at the P<0.05 level.</p

APE1 is induced by X-ray radiation in a dose-dependent manner in MHCC97L cells.

<p>Western blot analysis of cell lysates for the protein expression of APE1 at 48 h post irradiation. Normalized APE1 protein levels after adjusting for loading. *P<0.05, **P<0.01 vs control.</p

Combined treatment with Ad5/F35-siAPE1 and irradiation induces apoptosis <i>in vivo</i>.

<p>HepG2 or MHCC97L cells were treated with Ad5/F35-siAPE1 or Ad5/F35-EGFP; 48 h after infection, cells were irradiated (6 Gy), and apoptosis was determined at 24 h post irradiation by terminal dUTP nick end labeling (TUNEL) staining. (A) TUNEL staining of HepG2 xenograft. (B) TUNEL staining of MHCC97L xenograft. Data are expressed as percentage of apoptosis-positive cells examined with TUNEL. Bar graphs represent the mean values of triplicate determinations ± standard deviation. Lane 1, Ad5/F35-EGFP; lane 2, Ad5/F35-siAPE1; lane 3,Ad5/F35-EGFP+IR; lane 4, Ad5/F35-siAPE1+ IR.^*P<0.01 vs Ad5/F35-EGFP; ^#P<0.01 vs Ad5/F35-siAPE1; ^$P<0.01 vs Ad5/F35-EGFP+IR.</p