A pyrene-armed hexahomotrioxacalix[3]arene as a multi-sensor via synergistic and demetallation effects

A new pyrene-armed hexahomotrioxacalix[3]arene L has been synthesized, which exhibits a pronounced fluorescence enhancement response toward Cu²⁺ ions via a Zn²⁺ or Cd²⁺ triggered synergistic effect. Additionally, the L·Cu²⁺+ complex can subsequently serve as a sensor for F⁻ via anion-induced demetallation. The fluorescence responses by the input of Cu²⁺, Zn²⁺/Cd²⁺ and F⁻ can be constructed as a combinational logic gate which mimics a set of molecular traffic signals

Fluorescent turn-on sensors based on pyrene-containing Schiff base derivatives for Cu2+ recognition: spectroscopic and DFT computational studies

A new fluorescent chemosensor L1, pyrene containing long chain Schiff base derivative in 1-position has been synthesized. Similarly, the receptors L2 and L3 are also designed in order to compare the binding ability for detection of Cu2+. The receptors exhibit very weak fluorescence (Φ = 0.01) due to the photoinduced electron transfer (PET). Upon addition of 10 equiv. of Cu2+, the emission intensity of ligands L1 and L2 are increased 65-fold (Φ = 0.31) and 25-fold (Φ = 0.08) in CH3CN/CH2Cl2 solvents system respectively. NMR titration experiments, spectroscopic and DFT computational studies confirmed the binding phenomena and sensitivity of Cu2+

Study on adsorption mechanism of ammonia nitrogen in wastewater by natural heulandite

In order to explore the adsorption mechanism and optimal regeneration method of natural heulandite to high ammonia nitrogen wastewater, the natural heulandite from Hebei Province is selected as the research object. The adsorption kinetics, adsorption isotherms and adsorption thermodynamics are studied by single factor test. The results show that the adsorption process of ammonia nitrogen on heulandite with particle size range of 50~600 μm complies with the quasi-second order kinetic equation with ammonia nitrogen concentration of 500 mg/L at temperature of 25 ℃. Particle diffusion and liquid film diffusion are the dominated process of the adsorption. The adsorption capacity of heulandite is 7.81 mg/g at temperature of 45 ℃. The adsorption isotherm of ammonia nitrogen on the experimental heulandite is fitted well with Freundlich model. Gibbs free energy ΔG is calculated to be less than zero, indicating that the adsorption of ammonia nitrogen on the experimental heulandite is a spontaneous endothermic reaction. Additionally, the adsorption capacity of heulandite increases with appropriate increaseing in temperature. The optimal regeneration solvent of the saturated heulandite is 0.1 mol/L of NaCl, with which the desorption rate increases to 79%, and the times of elution and regeneration are more than 5. The results of this study can improve the economic benefits and environmental value of heulandite in the treatment of ammonia nitrogen wastewater. It can be seen that heulandite in the industrial wastewater treatment has broad prospects for application

Experimental study on advanced treatment of secondary effluent by Fenton oxidation-coagulation

In order to solve the problem of having excessive organics, total phosphorus(TP) and other pollutants in secondary effluent from municipal wastewater treatment plant, Fenton oxidation-coagulation unit is adopted to treat the wastewater. The treatment efficiency of the treatment process is discussed through the orthogonal experiments and the single factor experiments. It shows that the removal efficiency of COD, colority and TP are 97.5%, 96.7% and 99.2% respectively under the optimal reaction conditions that the Fenton oxidation reaction time is 40 min, initial pH value is 6.0, the dosage of FeSO4·7H2O and H2O2 are 600 mg/L and 850 mg/L respectively,the coagulation reacting pH value is 8.0 and the dosage of APAM is 3.0 mg/L. The water quality can meet the first A level discharge standard of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918—2002).The process, as the advanced treatment technology of wastewater, can be widely used in the advanced treatment of refractory pollutants in the municipal wastewater treatment plant

Characterization of the complete chloroplast genome of Hordeum jubatum (Poaceae: Pooideae: Triticeae) and phylogenetic analysis

Hordeum jubatum is a salt tolerant forage, which plays an important role in improving saline-alkali land and animal husbandry alkali-saline grassland. Hordeum jubatum has been gradually domesticated as an ornamental grass due to its special flower color. However, no domesticated varieties of H. jubatum plant have been reported worldwide. This study reported the complete chloroplast genome of wild H. jubatum, which was 136,871 bp in length, containing a pair of inverted repeats (IRA/IRB) of 21,608 bp separated by a small single-copy (SSC) area region of 12,799 bp and the large single-copy (LSC) region of 80,856 bp. A total of 133 genes, including 85 protein-coding genes (79 PCG species), 40 transfer RNA genes (32 tRNA species), and eight ribosomal RNA genes (four rRNA species) were predicted from the chloroplast genomes. The overall GC content was 38.25%, and the corresponding values of the LSC, SSC, and IR were 36.22%, 32.15%, and 43.85%, respectively. The phylogenetic analysis showed that wild H. jubatum was clustered closely with Hordeum bogdanii

Measurements of the mechanical properties of larch at elevated and high temperature under nitrogen conditions

The mechanical characteristics of wood members in a fire are reduced as a result of strength loss of the outermost charring layer and strength reduction of the secondary outer layer in high temperature zones. The charring layer has strong oxygen isolation effects. The main mechanical characteristics of larch wood, including modulus of elasticity (MOE), parallel-to-grain compressive (fc), tensile (ft), bending strengths (fb), and ductility coefficient, were determined under oxygen-free conditions at higher temperatures. Fourier transform-infrared (FT-IR) and scanning electron microscopies (SEM) were used to analyze chemical composition and microscopic changes of wood. The results suggested that hemicellulose softening resulted in decreases in mechanical properties of wood between 20 and 70 °C. From 70 to 190 °C, FT-IR spectroscopy provided evidence that increases in MOE and fc, with relatively minor changes in fb and ft, were associated with cellulose crystallinity and lignin cross-linking/condensation. The use of SEM further indicated degradation of wood composition

Regulation of Tyrosinase Gene Expression by Retinoic Acid Pathway in the Pacific Oyster <i>Crassostrea gigas</i>

Retinoic acid (RA) plays important roles in various biological processes in animals. RA signaling is mediated by two types of nuclear receptors, namely retinoic acid receptor (RAR) and retinoid x receptor (RXR), which regulate gene expression by binding to retinoic acid response elements (RAREs) in the promoters of target genes. Here, we explored the effect of all-trans retinoic acid (ATRA) on the Pacific oyster Crassostera gigas at the transcriptome level. A total of 586 differentially expressed genes (DEGs) were identified in C. gigas upon ATRA treatment, with 309 upregulated and 277 downregulated genes. Bioinformatic analysis revealed that ATRA affects the development, metabolism, reproduction, and immunity of C. gigas. Four tyrosinase genes, including Tyr-6 (LOC105331209), Tyr-9 (LOC105346503), Tyr-20 (LOC105330910), and Tyr-12 (LOC105320007), were upregulated by ATRA according to the transcriptome data and these results were verified by real-time quantitative polymerase chain reaction (RT-qPCR) analysis. In addition, increased expression of Tyr (a melanin-related TYR gene in C. gigas) and Tyr-2 were detected after ATRA treatment. The yeast one-hybrid assay revealed the DNA-binding activity of the RA receptors CgRAR and CgRXR, and the interaction of CgRAR with RARE present in the Tyr-2 promoter. These results provide evidence for the further studies on the role of ATRA and the mechanism of RA receptors in mollusks