Changes in physiology, antioxidant system, and gene expression in Microcystis aeruginosa under fenoxaprop-p-ethyl stress.

Fenoxaprop-p-ethyl (FE) is one of the typical aryloxyphenoxypropionate herbicides. FE has been widely applied in agriculture in recent years. Human health and aquatic ecosystems are threatened by the cyanobacteria blooms caused by Microcystis aeruginosa, which is one of the most common cyanobacteria responsible for freshwater blooming. Few studies have been reported on the physiological effects of FE on M. aeruginosa. This study analyzed the growth curves, the contents of chlorophyll a and protein, the oxidative stress, and the microcystin-LR (MC-LR) levels of M. aeruginosa exposed to various FE concentrations (i.e., 0, 0.5, 1, 2, and 5 mg/L). FE was observed to stimulate the cell density, chlorophyll a content, and protein content of M. aeruginosa at 0.5- and 1-mg/L FE concentrations but inhibit them at 2 and 5 mg/L FE concentrations. The superoxide dismutase and catalase activities were enhanced and the malondialdehyde concentration was increased by FE. The intracellular (intra-) and extracellular (extra-) MC-LR contents were also affected by FE. The expression levels of photosynthesis-related genes psbD1, psaB, and rbcL varied in response to FE exposure. Moreover, the expressions of microcystin synthase-related genes mcyA and mcyD and microcystin transportation-related gene mcyH were significantly inhibited by the treatment with 2 and 5 mg/L FE concentrations. These results might be helpful in evaluating the ecotoxicity of FE and guiding the rational application of herbicides in modern agriculture.

Selective surface enhanced Raman detection and effective photocatalytic degradation of sulfonamides antibiotic based on a flexible three-dimensional chitosan/carbon nitride/silver substrate.

The prevalence of sulfonamide residues in aquatic environments poses serious environmental risks, and the sensitive detection and effective degradation of sulfonamides have attracted widespread attention. Here, the environmentally friendly chitosan (CS)/carbon nitride (CN) with three-dimensional porous structure is fabricated by freeze-drying method, and subsequently a new bifunctional flexible substrate (CS/CN/Ag) is prepared by anchoring of small sized AgNPs (6 ∼ 12 nm) on CS/CN. Importantly, the CS/CN/Ag substrate shows high adsorption capacity (∼ 83.06%) for sulfamethoxazole (SMX) solution within 20 mins and the limit of detection can be as low as 7.46 × 10-9 mol·L-1 with an enhancement factor of 3.3 × 105. Also, the CS/CN/Ag substrate displays highly selective for surface-enhanced Raman spectroscopy (SERS) detection of sulfonamides and also shows excellent SERS response for SMX in hospital wastewater samples. In addition, the photocatalytic degradation efficiency of SMX could reach as high as 99.22% within 20 mins of irradiation and the CS/CN/Ag still maintains outstanding photocatalytic performance after six cycles. Moreover, the Ag content in the CS/CN/Ag substrate is only 2.35%, and also the CS/CN/Ag exhibits good uniformity, repeatability, recyclability and stability. Therefore, this flexible and cost-effectively substrate of CS/CN/Ag shows great potential for the simultaneous SERS detection and photocatalytic degradation of pollutants in actual wastewater samples.

Exploration of the Magnetic Flux Density on the Surface of Seamless Knitted Fabrics Manufactured with Magnetic Polypropylene Fibers.

In this paper, magnetic fibers were integrated with seamless knitting technology. Additionally, the raw materials for the outer fabrics and the relevant yarn feed ratio were designed, including the polypropylene yarn with different magnetic powder contents (0%, 10% and 50%) and its yarn feed ratio (100:0, 75:25, 50:50 and 25:75) to graphene viscose yarn. In addition, weft plain stitch, 1 + 1 mock rib and 1 + 3 mock rib were adopted to weave polyamide fiber/polyurethane fiber wrap yarn as the lining materials into 12 knitted fabric samples on a seamless knitting machine according to the partial addition method in the orthogonal experimental design. As per the test and analysis results of the magnetic flux density on the front and back surfaces of 12 seamless knitted fabrics, polypropylene yarn with different magnetic powder contents in outer fabrics is the most significant factor affecting the magnetic flux density on the surface, followed by the yarn feed ratio of outer fabrics and fabric stitches. The findings in this study can provide a reference and theoretical basis for the specification design of seamless knitted fabrics manufactured by magnetic fabrics to a certain extent.

Study on the Skin Hydration and Trans Epidermal Water Loss of Aloe Viscose Seamless Knitted Fabric for Autumn and Winter.

To explore the skin moisturizing performance of aloe viscose fiber seamless knitted fabric, this experiment takes the different yarn-blending ratios of aloe viscose fiber and viscose fiber, as well as three different tissue structures as factors, establishes a sample scheme according to full factor experimental tests on skin hydration and trans epidermal water loss (TEWL) after the sample fabric had been wrapped around the skin, and uses two-way and one-way ANOVA in SPSS and the Duncan multiple comparison method. The test data were analyzed to study the influence of different materials and the structure of the veil on the moisture retention of the fabric. The results show that the sample scheme with the largest change rate of skin hydration is when the raw material of the veil is aloe viscose/viscose 100/0 yarn, and the structure is 1 + 3 simulated rib. The sample scheme with the minimum change rate of TEWL is when aloe viscose/viscose 75/25 yarn is used as the raw material of the veil, and the structure is 1 + 1 simulated rib, which provides a theoretical basis for the research and development of moisturizing knitted fabric.

Synthesis of a CuNP/chitosan/black phosphorus nanocomposite for non-enzymatic hydrogen peroxide sensing.

A copper-chitosan-black phosphorus nanocomposite (CuNPs-Chit-BP) was fabricated by electrochemically depositing copper nanoparticles onto a black phosphorus-modified glassy carbon electrode in chitosan solution. CuNPs demonstrated a uniform distribution on the Chit-BP modified GCE with an average size of 20 nm. Electrochemical methods were used to study the catalytic activity of the CuNPs-Chit-BP nanocomposite toward hydrogen peroxide. The results showed that the synthesized nanocomposite exhibited excellent electrical conductivity, good biocompatibility and highly efficient electrocatalytic activity toward hydrogen peroxide reduction in the range of 10 µM-10.3 mM with a detection limit of 0.390 µM. The present work proposed a new strategy to explore novel BP-based non-enzymatic biosensing platforms.

[Simultaneous determination of vitamins B1, B2, B6, niacinamide and calcium pantothenate in compound vitamin B tablets by high performance quantitative capillary electrophoresis].

A high performance quantitative capillary electrophoresis method was developed for the simultaneous determination of vitamins B1, B2, B6, nicotinamide, and calcium pantothenate in vitamin B tablets using a quantitative capillary electrophoresis instrument. The samples were extracted ultrasonically with acetonitrile-water (20:80, v/v). The automatic high precision quantitative capillary electrophoresis instrument was used to realize quantitative injection through a 10 nL injection valve. The background electrolyte was selected as 40 mmol/L sodium borate buffer (pH 9.0), which was continuously supplied by a microfluidic injection pump. The working voltage was -10 kV. The detection wavelength of vitamins B1, B2, B6, and nicotinamide was selected as 280 nm, which was then changed to 210 nm to detect calcium pantothenate. The result showed good linearities between the peak area and the concentration of vitamins B1, B2, B6, nicotinamide, and calcium pantothenate in the correlation coefficients (r) range of 0.9968-0.9998. The limits of detection (LODs) were in the range of 2.5-36.0 mg/L. The average recoveries were 94.1%-98.9% with relative standard deviations (RSDs) as 1.3%-1.9%. The method is precise, reliable, and suitable for the simultaneous determination of vitamins B1, B2, B6, nicotinamide, and calcium pantothenate in a real compound vitamin B tablet.

Synthesis of a Poly-l-Lysine/Black Phosphorus Hybrid for Biosensors.

A simple, noncovalent modification strategy was proposed to synthesize poly-l-lysine-black phosphorus (pLL-BP) hybrid. BP nanoflakes were prepared with a water-phase exfoliation method. pLL can adhere to the surface of BP via hydrophobic interaction between butyl chains of pLL and the BP surface as well as the electrostatic interaction between the protonated amino groups on pLL and the negative charge on deprotonated PxOy groups remaining on BP. The as-synthesized pLL-BP hybrid turns out to be an ideal matrix for hemoglobin immobilization and direct electron transfer. Good conductivity and biocompatibility of BP maintain the native structure and the bioactivity of hemoglobin (Hb), facilitating the direct electron transfer between the electroactive center of Hb and electrode. The rate constant ( kET) for direct electron transfer of Hb@pLL-BP is calculated to be 11.24 s-1. The constructed Hb-pLL-BP based enzymatic electrochemical biosensor displays excellent catalytic activity toward the reduction of oxygen and hydrogen peroxide. The electrochemical response toward H2O2 exhibits a linear dependence on hydrogen peroxide concentration ranging between 10 µM and 700 µM. The results demonstrate that the pLL-BP hybrid can act as a biocompatible building block for the construction of novel biofuel cells, bioelectronics, and biosensors.

Dioxygen in combination with hydrazine: a practical system for degradation of a broad spectrum of toxic organics in water.

Green and cost-effective eradication of pollutants from water is an important and long-standing goal in environmental chemistry. A broad spectrum of toxic organics in water was efficiently destroyed in the presence of dioxygen in combination with hydrazine hydrate at 150 °C. Under this operating condition, two typical classes of toxic organic chemicals, phenols and nitrobenzene derivatives were totally destroyed. The mineralization rate of these organics was 35-86%. Furthermore, when this degradation system was applied to degradation of actual waste water of wood pulp bleaching with chlorine (COD: 1830 mg/L), 77% COD decrease and 52% TOC mineralization of the wastewater were observed. In each case, the major degradation products are small molecular compounds, such as methanol, formic acid and acetic acid except CO/CO(2). In the case of chlorophenols degradation, no dioxins and any other toxic compounds are detected by (1)H NMR. After degradation reaction, the hydrazine was also decomposed into N(2) and H(2)O, and no remaining hydrazine is found.