In this study electrospun nanofibers of partially sulfonated polyether ether ketone have been produced as a preliminary step for a possible development of composite proton exchange membranes for fuel cells. Response surface methodology has been employed for the modelling and optimization of the electrospinning process, using a Box-Behnken design. The investigation, based on a second order polynomial model, has been focused on the analysis of the effect of both process (voltage, tip-to-collector distance, flow rate) and material (sulfonation degree) variables on the mean fiber diameter. The final model has been verified by a series of statistical tests on the residuals and validated by a comparison procedure of samples at different sulfonation degrees, realized according to optimized conditions, for the production of homogeneous thin nanofibers.
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http://dx.doi.org/10.3390/ma8074096 | DOI Listing |
Inorg Chem
January 2025
Henan Provincial Key Laboratory of Surface and Interface Science, Zhengzhou University of Light Industry, Zhengzhou 450002, P. R. China.
Three two-dimensional (2D) chiral Ag(I) complexes with formulas [Ag(L)(5-nipa)] (), [Ag(L)(5-nipa)] (), and {[Ag(L)(5-hipa)]·2HO} () were prepared through the reactions of AgO with enantiopure -monodentate N-donors (L/L) and different dicarboxylic acids bearing A (acceptor)-π-- and D (donor)-π--type structural features, where / = (-)/(+)-2-(4'-pyridyl)-4,5-pinene-pyridine, 5-Hnipa = 5-nitroisophthalic acid, and 5-Hhipa = 5-hydroxyisophthalic acid. A study of their nonlinear optical responses reveals that chiral and enantiomeric pairs with the A-π--type dicarboxylic acid ligand simultaneously display second- and third-harmonic generation (SHG and THG) responses, while chiral containing the D-π--type dicarboxylic acid ligand only exhibits a very strong THG response. The THG intensity of is 451 × α-SiO, being about 27 and 24 times larger than those of and , respectively.
View Article and Find Full Text PDFMedicine (Baltimore)
January 2025
Department of Otorhinolaryngology, Head and Neck Surgery, School of Medicine, Kyungpook National University, Kyungpook National University Chilgok Hospital, Daegu, South Korea.
Rationale: Nasopharyngeal tuberculosis (TB), a rare form of tuberculosis outside the lungs, can affect any organ or tissue in the body. It is difficult to diagnose because of nonspecific symptoms, often leading to delayed confirmation after the initial patient visit. Clinical manifestations such as cervical lymphadenopathy and irregular mucosal surfaces can be challenging to distinguish from nasopharyngeal cancer or malignant lymphoma.
View Article and Find Full Text PDFFood Addit Contam Part A Chem Anal Control Expo Risk Assess
January 2025
Department of Chemistry, National Kaohsiung Normal University, Kaohsiung City, Taiwan.
Pyrethroids are synthetic chemicals that account for 16% of the international insecticide market and have been shown to be of varying toxicity to different species. There are various methods available for detecting pyrethroids in agricultural products, but these products must be pre-treated to remove interference from the food matrix, such as through dispersion liquid-liquid microextraction (DLLME). This study employed two experimental design methods to optimize the continuous and discontinuous experimental parameters of DLLME and investigated whether DLLME combined with GC-NICI-MS is effective for detecting pyrethroids in agricultural products.
View Article and Find Full Text PDFEnviron Microbiol
January 2025
Institute of Microbiology and Dahlem Centre of Plant Sciences, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany.
The leaf surface, known as the phylloplane, presents an oligotrophic and heterogeneous environment due to its topography and uneven distribution of resources. Although it is a challenging environment, leaves support abundant bacterial communities that are spatially structured. However, the factors influencing these spatial distribution patterns are not well understood.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
The Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Peroxy radicals are key intermediates in many atmospheric processes. Reactions between such radicals are of particular interest as they can lead to accretion products capable of participating in new particle formation (NPF). These reactions proceed through a tetroxide intermediate, which then decomposes to a complex of two alkoxy radicals and O, with spin conservation dictating that the complex must be formed in the triplet state.
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