An ultra-broadband terahertz metamaterial coherent absorber using multilayer electric ring resonator structures based on anti-reflection coating.

We propose a method for achieving THz ultra-broadband coherent absorption using the anti-reflection theory of metamaterials. The metamaterial absorber consists of a periodic array of electric ring resonators with a multilayered structure which form the desired refractive index dispersion and provide continuous anti-reflection over a wide frequency range. The destructive interference mechanism and resonance absorption of the absorber are determined by simulation analysis and numerical simulation.

Magnetic solid-phase extraction of tobacco-specific N-nitrosamines using magnetic graphene composite as sorbent.

Tobacco-specific N-nitrosamines are carcinogenic components in mainstream cigarette smoke. To explore tobacco-specific N-nitrosamine release levels in cigarettes, a magnetic solid-phase extraction procedure using magnetic graphene composite as sorbent for fast enrichment of tobacco-specific N-nitrosamine was developed. Under optimal conditions, a tobacco-specific N-nitrosamine determination method was successfully proposed by combining magnetic solid-phase extraction procedure and high-performance liquid chromatography coupled with tandem mass spectrometry.

Three-Dimensional Resistive Metamaterial Absorber Loaded with Metallic Resonators for the Enhancement of Lower-Frequency Absorption.

Resistive patch array incorporating with metallic backplane provided an effective way to achieve broadband metamaterial absorbers (MAs) in microwave frequency, and the outstanding construction contributed more flexible and diversified broadband absorption. In this paper, we attempted to load metallic resonators (MRs) to three-dimensional resistive MA to further enhance the lower-frequency absorption performance. Simulation showed that the partial absorption peak was separated to the lower frequency, while the rest of broadband absorption was unaffected.

Simultaneous determination of polycyclic aromatic hydrocarbons and tobacco-specific N-nitrosamines in mainstream cigarette smoke using in-pipette-tip solid-phase extraction and on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry.

In this study, a silica/primary secondary amine (SiO2/PSA) was used as an in-pipette-tip solid phase extraction (SPE) sorbent for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs) and tobacco-specific N-nitrosamines (TSNAs) in mainstream cigarette smoke (MSS). We investigated several parameters including an extraction procedure of total particulate matter, type and amount of sorbent and on-line gel permeation chromatography parameters to obtain optimum conditions for a new strategy to target analytes. Under the optimized conditions, we developed a method for the simultaneous determination of PAHs and TSNAs in MSS by coupling in-pipette-tip SPE procedures to an on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry (on-line GPC-GC-MS(2)).

Magnetic graphene as modified quick, easy, cheap, effective, rugged and safe adsorbent for the determination of organochlorine pesticide residues in tobacco.

In this study, magnetic graphene was used as modified quick, easy, cheap, effective, rugged and safe (QuEChERS) adsorbent for the determination of organochlorine pesticide (OCPs) residues in tobacco. To achieve the optimum conditions of modified QuEChERS procedure toward target analytes, several parameters affecting the clean-up efficiency including the amount of the adsorbent and clean-up time were investigated. Under the optimized conditions, a method for the determination of 26 OCPs residues in tobacco was established by coupling the modified QuEChERS procedure to on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry (on-line GPC-GC-MS(2)).

Evaluation of the cytotoxicity of cigarette smoke condensate by a cellular impedance biosensor.

In this study, a cytotoxicity assay was developed for profiling the cytotoxicity of cigarette smoke condensates (CSCs) base on a cellular impedance biosensor (CIB). Compared with the traditional in vitro cytotoxicity assays, this CIB-based method offered distinct advantages in real-time kinetic measurement which provided a comprehensive understanding of cellular responses for the entire duration of the experiment and prediction of the potential mechanism of action of a given treatment. The time-dependent cell response profiles provided valid evidences for optimization of cell number per well, cell quality control, and identification of the optimal time points for compound treatment and endpoint assays.

Determination of noradrenaline and dopamine in pharmaceutical injection samples by inhibition flow injection electrochemiluminescence of ruthenium complexes.

Two maximal potential-resolved flow injection-electrochemiluminescent (FI-ECL) peaks were observed for Ru(bpy)(3)(2+)/TPrA system at 0.90 and 1.05 V, and for Ru(phen)(3)(2+)/TPrA at 1.

Flow-injection determination of streptomycin residues in milk using the luminol-periodate-Mn2+ chemiluminescence system.

A novel flow-injection method with chemiluminescence detection was developed for the determination of streptomycin residues in milk, based on the enhancement by streptomycin of the luminol-potassium periodate-Mn(2+) chemiluminescence system. The assay allowed analysis of streptomycin residues in whole milk samples ( approximately 3.5% fat) after sample work-up procedures.

Flow injection analysis of tetracyclines using inhibited Ru(bpy)3(2+)/tripropylamine electrochemiluminescence system.

Tetracyclines (TCs) were found to strongly inhibit the electrochemiluminescence (ECL) from the Ru(bpy)3(2+)-tripropylamine system when a working Pt electrode was maintained at 1.05 V (vs. Ag/AgCl) in pH 8.

Flow injection analysis of gallic acid with inhibited electrochemiluminescence detection.

A flow injection (FI)-electrochemiluminescent (ECL) method has been developed for the determination of gallic acid, based on an inhibition effect on the Ru(bpy)(3)(2+)/tri- n-propylamine (TPrA) ECL system in pH 8.0 phosphate buffer solution. The method is simple and convenient with a determination limit of 9.