Interacting with luteinizing hormone receptor provides a new elucidation of the mechanism of anti-androgenicity of bisphenol S.

Bisphenol S (BPS) exhibited inhibitory effects on androgen synthesis, but its target of action remains unclear. We investigated the effects of BPS exposure at environmentally relevant concentrations (1 µg/L, 10 µg/L and 100 µg/L) for 48 h on androgen synthesis in rat ovarian theca cells and explored the underlying mechanisms, target site and target molecule. The results showed that BPS exposure inhibited the transcript levels of steroidogenic genes and reduced the contents of androgen precursors, testosterone and dihydrotestosterone. BPS exposure decreased the phosphorylation levels of extracellular signal-related kinase 1/2 (ERK1/2), and the inhibitory effects of BPS on testosterone content and steroidogenic gene expression were blocked by ERK1/2 agonist LY2828360, suggesting that ERK1/2 signaling pathway mediates the inhibitory effects of BPS on androgen synthesis. BPS mainly accumulated on the cell membrane, impermeable BPS-bovine serum albumin exposure still inhibited androgen synthesis, BPS interacted with rat luteinizing hormone receptor (LHR) via formation of hydrogen bonds in the transmembrane region, and the inhibitory effects of BPS on ERK1/2 phosphorylation were blocked by luteinizing hormone (the natural agonist of LHR), indicating that LHR located on the cell membrane is the target of action of BPS. This paper provides a new elucidation of the mechanism of anti-androgenicity of BPS, especially for the non-genomic pathways.

Dielectric behavior of Fe3N@C composites with green synthesis and their remarkable electromagnetic wave absorption performance.

Fe3N has been considered as a new generation of ideal ferromagnetic materials with the virtues of high saturated magnetization and high resistance to oxidation. However, a facile and eco-friendly fabrication of Fe3N still needs to be investigated. Herein, the gelatin derived from fish skin was chosen as the raw material of carbon and the amino acid inherent in fish skin can act as a nitrogen source for the generation of Fe3N. Besides, the influence of graphitization degree to dielectric behavior of composites was further investigated. In this work, the composites fabricated by 0.8 mmol Fe(NO3)3 exhibited optimal absorption performance with the minimum reflection loss of -77.6 dB at 2.2 mm. Besides, the absorption bandwidth was detected as 7.76 GHz (covering from 10.24 to 18 GHz) at the matching thickness of 2.7 mm. According to the analysis of dielectric constant, the degree of graphitization affects the dielectric behavior mainly in determining the orientation speed of the dipole and the conductive loss. This work provides a new thought for the investigation of the electromagnetic absorption mechanism of composite.

Design and synthesis of NiCo/Co4S3@C hybrid material with tunable and efficient electromagnetic absorption.

Producing electromagnetic wave absorbers with high absorption capacity and wide absorption bandwidth is still a challenge task, which limits its application in human life. In this study, a novel carbon-coated NiCo alloy/Co4S3 hybrid material was fabricated by a simple strategy. By adjusting the annealing temperature, the electromagnetic wave absorption property of NiCo/Co4S3@C hybrid material can be further improved. Herein, the NiCo/Co4S3@C hybrid material obtained at 750 °C exhibits satisfactory electromagnetic wave absorption performance. The minimum reflection loss value of -56.96 dB is obtained at 10.32 GHz, and the matching thickness is only 2.71 mm. When the thickness of the absorber is in the range of 1.8-5.0 mm, the effective absorption bandwidth is controlled between 4.64 and 18 GHz. The satisfactory properties of the hybrid materials are attributed to the space charge polarization caused by heterogeneous NiCo alloys, interfacial polarization between components and good impedance matching characteristics. The results show that NiCo/Co4S3@C hybrid material is a potential electromagnetic wave absorber.

Determination of eight quinolones in milk using immunoaffinity microextraction in a packed syringe and liquid chromatography with fluorescence detection.

We have established a new, highly selective, and sensitive method for the determination of eight quinolones (QNs) in milk: danofloxacin, enrofloxacin, orbifloxacin, norfloxacin, ofloxacin, lomefloxacin, fleroxacin, and ciprofloxacin. The method uses immunoaffinity microextraction in a packed syringe and liquid chromatography with fluorescence detection (IA-MEPS-LC-FLD). Traditionally, QN residues are determined by liquid-liquid extraction (LLE) and solid phase extraction (SPE) sample preparation techniques; however, these methods are time-consuming and require large quantities of organic solvents. We thus developed a novel immunoaffinity adsorbent combined with MEPS for QN residue analysis. The syringe was filled with 0.2g of microbeads bound with a QN monoclonal antibody using glutaraldehyde. The relevant parameters of the IA-MEPS method were optimized and discussed herein. Milk samples were extracted at a flow rate of 3.5mL/min, 600µL of methanol-and phosphate-buffered saline (9:1, v/v) was used for elution, and 200µL of mobile phase was used for reconstitution after the sample was dried with nitrogen. Then, the sample was detected by LC-FLD. For the eight QNs, the limit of detection ranged from 0.05 to 0.1ng/g, the limit of quantification ranged from 0.15 to 0.3ng/g, and the intra- and inter-day precision were 3.2%-14.6% and 9.1%-15.8%, respectively. The advantages of the IA-MEPS method includ simple operation, low cost and reduced organic solvent use. Moreover, the sample pretreatment is environmentally friendly because of the reduced solvent volume requirements.

Development of immunoaffinity solid phase microextraction rods for analysis of three estrogens in environmental water samples.

In this study, immunoaffinity solid phase microextraction (SPME) rods were developed for the analysis of diethylstilbestrol (DES), hexestrol (HES) and dienestrol (DIS) followed by ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). This immunoaffinity SPME device was built with three stainless steel rods bundled together as one and modified with porous silicate particles. As an extraction sorbent, antibody immobilization approach was employed based on the covalent attachment of the anti-diethylstilbestrol monoclonal antibody (mAb) onto the rods. The immunoaffinity SPME rod was characterized and confirmed by scanning electron microscopy and X-ray photoelectron spectroscopy analysis. The porous network showed a very large active surface area and significantly increased the adsorption capacity which can reach 49.6pmol/cm2. Moreover, the immunoaffinity sorbent showed good sturdiness at least 10 times with stable extraction performance. Once the main experimental parameters were optimized, the method was used to detect DES, HES and DIS in environmental water samples. The limits of detection for the three estrogens were 0.05-0.15ng/mL, and the limits of quantification was 0.5ng/mL. The average recoveries ranged from 34.2 to 62.7% were achieved with good intra-day and inter-day precision ranging from 7.8 to 12.7% and from 8.2 to 13.5% respectively. The newly developed immunoaffinity SPME showed high adsorption capacity, good sensitivity and reproducibility and was successfully applied to the analysis of DES, HES and DIS in environmental water samples.