Numerical Simulation of Polyacrylamide Hydrogel Prepared via Thermally Initiated Frontal Polymerization.

Traditional polymer curing techniques present challenges such as a slow processing speed, high energy consumption, and considerable initial investment. Frontal polymerization (FP), a novel approach, transforms monomers into fully cured polymers through a self-sustaining exothermic reaction, which enhances speed, efficiency, and safety. This study focuses on acrylamide hydrogels, synthesized via FP, which hold significant potential for biomedical applications and 3D printing. Heat conduction is critical in FP, particularly due to its influence on the temperature distribution and reaction rate mechanisms, which affect the final properties of polymers. Therefore, a comprehensive analysis of heat conduction and chemical reactions during FP is presented through the establishment of mathematical models and numerical methods. Existing research on FP hydrogel synthesis primarily explores chemical modifications, with limited studies on numerical modeling. By utilizing Differential Scanning Calorimetry (DSC) data on the curing kinetics of polymerizable deep eutectic solvents (DES), this paper employs Malek's model selection method to establish an autocatalytic reaction model for FP synthesis. In addition, the finite element method is used to solve the reaction-diffusion model, examining the temperature evolution and curing degree during synthesis. The results affirm the nth-order autocatalytic model's accuracy in studying acrylamide monomer curing kinetics. Additionally, factors such as trigger temperature and solution initial temperature were found to influence the FP reaction's frontal propagation speed. The model's predictions on acrylamide hydrogel synthesis align with experimental data, filling the gap in numerical modeling for hydrogel FP synthesis and offering insights for future research on numerical models and temperature control in the FP synthesis of high-performance hydrogels.

Review on Soil Corrosion and Protection of Grounding Grids.

The corrosion of grounding grid materials in soil is a prominent factor in power and electrical equipment failure. This paper aims to delve into the corrosion characteristics of grounding grid materials and the corresponding methods of safeguarding against this phenomenon. Firstly, the influencing factors of the soil environment on the corrosion of the grounding grid are introduced, including soil physicochemical properties, microorganisms, and stray currents. Then, the corrosion behavior and durability of common grounding grid materials such as copper, carbon steel, and galvanized steel are discussed in detail and compared comprehensively. In addition, commonly used protective measures in China and outside China, including anti-corrosion coatings, electrochemical protection, and other technologies are introduced. Finally, it summarizes the current research progress and potential future directions of this field of study.

Starch as a reinforcement agent for poly(ionic liquid) hydrogels from deep eutectic solvent via frontal polymerization.

For the first time, conductive starch/poly(ionic liquid) hydrogels from a polymerizable deep eutectic solvent (DES) by frontal polymerization (FP) were reported. The solubility and dispersibility for starch granules in the polymerizable DES was investigated. The effects of starch content on FP behaviors, mechanical properties and electrical conductivity of composite hydrogels were studied. Results showed that starch could be partially dissolved and dispersed in the DES. Comparing with the pure poly(ionic liquid) hydrogel from DES (the tensile strength was 41 K Pa), the tensile strength of composite hydrogel could increased by 3.07 times and reached 126 K Pa. When the fixed strain was 80 %, its compressive strength could increase by 6 times and reaches 16.8 MPa. The main reason was that there was a strong interfacial interaction between starch and the polymer hydrogel network. The starch/poly(ionic liquid) composite hydrogels also had good electrical conductivity. Absorption of water could increase the conductivity of the composite hydrogel significantly.

[Development of questionnaire on influencing factors of quality of life in patients with sudden deafness based on Green model].

Objective:To develop a questionnaire with good reliability and validity that can comprehensively evaluate the influencing factors of life quality of patients with sudden deafness. Method:Based on the Green model and literature review, group discussions, semi-structured interviews and Delphi expert inquiries, an initial questionnaire was developed. From May 2018 to April 2019, 170 patients with sudden deafness in otolaryngology head and neck surgery in 2 comprehensive tertiary level A hospitals in Shanxi Province were selected for investigation by convenient sampling method. Through the critical ratio method and correlation analysis method, the data of each item are sorted and analyzed. The structural validity of the questionnaire was tested by exploratory factor analysis. The content validity of the questionnaire was evaluated by calculating the content validity index through expert inquiry. The reliability of the questionnaire was determined by calculating Cronbach's α coefficient and retesting the questionnaire, and finally a formal questionnaire was formed. Result:The questionnaire on influencing factors of life quality for patients with sudden deafness based on Green model includes 5 dimensions and 31 items including knowledge factors, attitude factors, behavior factors, contributing factors and reinforcement factors. The results of project analysis showed that the critical ratio of each item was 8.09-44.77（P<0.05）. Except items 8, 11 and 13, the pearson correlation coefficient between the other items and the total score is>0.3. The KMO value of the questionnaire was 0.844, and the 2 value of Bartlett's spherical test was 3218, P<0.001. Using the principal component analysis method, five common factors were extracted, named as knowledge factor, attitude factor, behavior factor, contributing factor and reinforcing factor, respectively, the cumulative variance contribution rate was 60.905%. The content validity index of the questionnaire level was 0.955, the content validity index at item level is 0.786-0.981; Cronbach's α coefficient at the questionnaire level was 0.875, Cronbach's α coefficient of each dimension is 0.780-0.912; The retest reliability of the questionnaire level was 0.88, the retest reliability of each dimension is 0.810-0.913. Conclusion:The questionnaire on influencing factors of quality of life for patients with sudden deafness based on Green model has good reliability and validity, and can be used as a tool for evaluating influencing factors of quality of life for patients with sudden deafness.

Drug-loaded zein nanofibers prepared using a modified coaxial electrospinning process.

This study investigated the preparation of drug-loaded fibers using a modified coaxial electrospinning process, in which only unspinnable solvent was used as sheath fluid. With zein/ibuprofen (IBU) co-dissolving solution and N, N-dimethylformamide as core and sheath fluids, respectively, the drug-loaded zein fibers could be generated continuously and smoothly without any clogging of the spinneret. Field emission scanning electron microscopy and transmission electron microscopy observations demonstrated that the fibers had ribbon morphology with a smooth surface. Their average diameters were 0.94±0.34 and 0.67±0.21 µm when the sheath-to-core flow rate ratios were taken as 0.11 and 0.25, respectively. X-ray diffraction and differential scanning calorimetry verified that IBU was in an amorphous state in all fiber composites. Fourier transform infrared spectra showed that zein had good compatibility with IBU owing to hydrogen bonding. In vitro dissolution tests showed that all the fibers could provide sustained drug release files via a typical Fickian diffusion mechanism. The modified coaxial electrospinning process reported here can expand the capability of electrospinning in generating fibers and provides a new manner for developing novel drug delivery systems.

Measurement of pyrene in the gills of exposed fish using synchronous fluorescence spectroscopy.

A synchronous fluorescence spectroscopy (SFS) method was developed for determination of pyrene in the gills of exposed fish. The wavelength differences (Δλ) of 50 nm was maintained between excitation and emission wavelengths and it was found to be suitable for the effective determination of pyrene in fish gills; the peak were observed at λ(ex) 334.5 nm. Linear relationships between SFS intensity and the concentration of pyrene in n-hexane solution were established. It was demonstrated that the SFS method was effective, simple, and less expensive, providing an attractive alternative for the rapid analysis of pyrene in fish gills.

Removal of crystal violet from aqueous solution by sorption into semi-interpenetrated networks hydrogels constituted of poly(acrylic acid-acrylamide-methacrylate) and amylose.

The dynamic remove of Crystal Violet (CV) by Semi-IPN hydrogels constituted of poly(acrylic acid-acrylamide-methacrylate) and amylose was studied. Adsorption capacity, kinetic and isotherm studies of CV onto hydrogels have been evaluated. It was found that the sorption process agreed very well with the Langmuir model and the adsorption of CV depended on the length of the side chain, amylose content and pH of the solution. For three types of hydrogels, n1-1, n2-1 and n4-1, the equilibrated amounts of CV adsorbed on the hydrogels decreased in the following order: n4-1 (28.6 mg/g)>n2-1 (25.0 mg/g)>n1-1 (20.0mg/g). Increasing the amylose content led to decrease the equilibrated amounts of CV adsorbed on the hydrogels. Moreover, adsorption kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step.