Bacterial infections have accompanied humanity throughout its history and became vitally important in the pandemic area. The most pathogenic bacteria are multidrug-resistant strains, which have become widespread due to their natural biological response to the use of antibiotics, including uncontrolled use. The current challenge is finding highly effective antibacterial agents of natural origin, which, however, have low solubility and consequently poor bioavailability. Curcumin, derived from Curcuma longa, is an example of a natural biologically active agent with a wide spectrum of biological effects, particularly against Gram-positive bacteria. However, curcumin exhibits extremely low antibacterial activity against Gram-negative bacteria. Curcumin’s hydrophobicity limits its use in medicine. As such, various polymeric systems have been used, especially biopolymer-based electrospun nanofibers. In the present study, the technological features of the fabrication of curcumin-loaded hyaluronic acid-based nanofibers are discussed in detail, their morphological characteristics, wettability, physico-chemical properties, and curcumin release profiles are demonstrated, and their antibacterial activity against multi-drug resistant ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are evaluated. It is noteworthy that the fibers containing a stable HA–curcumin complex showed high antibacterial activity against both Gram-positive and Gram-negative bacteria, which is an undeniable advantage. It is expected that the results of this work will contribute to the development of antibacterial drugs for topical and internal use with high efficacy and considerably lower side effects.

Optimizing the properties of electrospun polymer-perovskite nanofibers is considered essential for improving the performance of flexible optoelectronic devices. Here, the influence of electrospinning setup parameters (i.e., electrical voltage, collector type (planar or rotary), rotation speed, as well as process time) on the properties (i.e., external structure, perovskite crystallinity, optical properties, thermal properties, the shrinkage ratio, mechanical properties, and long-term stability) of electrospun polyvinylpyrrolidone nanofibers modified with cesium lead iodide nanocrystals has been studied. The results have shown that the structure of nanofibers is related to the electrical voltage, collector rotation speed, and process duration. Perovskite crystallinity and light absorption have improved by increasing the electrical voltage or/and the process time. The polymer’s glass transition temperature is affected by the embedded perovskite and the collector’s rotation speed. The shrinkage ratio and mechanical properties of nanofibers have been controlled by the rotation speed and the electrical voltage. The shrinkage is caused by the stress created in the nanofibers during the electrospinning process. The best mechanical properties can be noticed with the rotary collector at a rotational speed of 500--750 rpm. Nanofibers have shown good long-term stability and high thermal stability. The long-term stability is inversely proportional to the value of the electrical voltage.

In this work, a nanofiber mat based on PHB/PEG with various PEG contents was obtained by electrospinning process. The thermal and mechanical properties of the PHB/PEG nanofiber mat were investigated. In addition, PHB/PEG nanofiber mats were characterized by Fourier transforms infrared spectroscopy (FTIR), differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and water contact angle measurement. It was shown that, by increasing the PEG contents from 1 to 4%, the average diameter of PHB nanofibers decreased from 1177 nm to 1101 nm, corresponding to 2% PEG, then the diameter of the fiber increased again from 1101 nm to 1136 nm, corresponding to 4% PEG. Tensile strength increased from 3.6 MPa to 4.4 MPa, then decreased from 4.4 MPa to 2.9 MPa. Thermogravimetric analysis showed a difference in the process of thermal degradation of nanofiber mats. The degree of crystallinity measured by XRD and DSC methods gives different values at some points. The results demonstrated that adding PEG improved the mechanical properties, hydrophobicity, porosity, and thermal stability of the PHB fiber mat, which showed that the PHB/PEG nanofiber mat has great potential for air filtration or water filtration.

Bulk (Al _x Ga_1−x )₂O₃ crystals with an Al fraction x in the range from 0.0 to 0.23 were successfully grown by the Czochralski method. An increase in the band gap from 4.7 to 5.1 eV with the rise of the Al content was demonstrated by analyzing optical transmission spectra. The crystal quality of the obtained samples was characterized by X-ray diffractometry. The appearance of the crystal’s mosaic blockness was found for the Al fraction x above 0.05.

Bulk crystals of β-Ga2O3 were successfully grown by the edge-defined film-fed growth method. The crystalline quality of the obtained crystals was analyzed by the method of x-ray diffractometry. The full width at half maximum of the rocking curve was about 72 arcsec. The optical bandgap was determined by analyzing the optical transmission spectra and amounted to 4.7 eV. The hot disk method was used to obtain the thermal conductivity of the sample along the [001] direction in the temperature range from 30 to 120 °C. The maximum value of thermal conductivity obtained at 30 °C was 9.25 W/(m K).