This paper presents an efficient method to generate high-order Bessel–Gauss beams carrying orbital angular momentum (OAM) by using a thin and compact optical element such as a multilevel spiral axicon. This approach represents an excellent alternative for diffraction-free OAM beam generation instead of complex methods based on a doublet formed by a physical spiral phase plate and zero-order axicon, phase holograms loaded on spatial light modulators (SLMs), or the interferometric method. Here, we present the fabrication process for axicons with 16 and 32 levels, characterized by high mode conversion efficiency and good transmission for visible light (λ = 633 nm wavelength). The Bessel vortex states generated with the proposed diffractive optical elements (DOEs) can be exploited as a very useful resource for optical and quantum communication in free-space channels or in optical fibers.

Concentrated collagen hydrolysate (HC10CC), rabbit collagen glue (RCG), and keratin hydrolysate (KH) were investigated in terms of their extraction from mammalian by-products and processing by electrospinning. The electrospun nanofibers were characterized by scanning electron microscopy coupled with the energy dispersive X-ray spectroscopy (SEM/EDS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), and indentation tests. The cytotoxicity of the electrospun nanofibers was conducted on L929 fibroblast cells using MTT and LDH assays and cell morphology observations. The electrospun RCG and KH nanofibers morphology showed an average size of nanofibers ranging between 44 and 410 nm, while the electrospun HC10CC nanofibers exhibited higher sizes. The ATR-FTIR spectra performed both on extracted proteins and electrospun nanofibers showed that the triple helix structure of collagen is partially preserved. The results were in agreement with the circular dichroism analysis for protein extracts. Furthermore, the viscoelastic properties of electrospun KH nanofibers were superior to those of electrospun RCG nanofibers. Based on both in vitro quantitative and qualitative analysis, the electrospun nanofibers were not cytotoxic, inducing a healthy cellular response. The results of new electrospun protein-based nanofibers may be useful for further research on bioactive properties of these nanofibers for tissue engineering.

The adhesive bonds that ensure the appropriate mechanical properties for metal joining imply the surface chemical and wetting modification characteristics of the substrates. In this work, matrix-assisted pulsed laser evaporation (MAPLE) was used for the surface modification of Al via the deposition of two chemical compounds, polyvinyl alcohol (PVA) and triethanolamine (TEA), from frozen aqueous solutions. The deposition of the TEA and PVA layers was evidenced by FT-IR, SEM, and AFM analysis. The contact angle measurements evidenced the change in the hydrophilicity of the surface and surface free energies. The performance of the commercial silyl-based polymer adhesive Bison Max Repair Extreme Adhesive^® was evaluated by tensile strength measurements. This method led to a change in tensile strength of 54.22% in the case of Al-TEA and 36.34% for Al-PVA compared with the control. This study gives preliminary insights into using MAPLE, for the first time in adhesive applications, as a pretreatment method for Al plates for adhesive bonding reinforcement.

Ferroelectricity in hafnium oxide (HfO₂)-based thin films has emerged as a scalable pathway toward CMOS-compatible non-volatile memories and logic devices. This study examines how dopant chemistry and film thickness influence the stabilization of the ferroelectric phase in ALD-grown HfO₂ thin films doped with Zr, Al, and Y. Structural, morphological, and electrical characterizations were carried out using AFM, GIXRD, P–E, in-plane I/W–E, and C–V measurements on films with thicknesses of 7 nm and 100 nm. AFM revealed atomically smooth and dense surfaces (R_q < 0.5 nm), while GIXRD confirmed the stabilization of the orthorhombic Pca2₁ phase in doped 7 nm films and its relaxation toward the monoclinic phase at 100 nm. The 7 nm HfZrO and HfYO films exhibited robust ferroelectric hysteresis with remanent polarization values up to 60 μC·cm⁻², whereas HfAlO showed a narrower but still distinct switching response. In-plane I/W–E characteristics indicated a combination of Poole–Frenkel and injection-limited conduction, consistent with defect-assisted polarization reversal and asymmetric contact barriers. At 100 nm, all films showed reduced polarization and partially dielectric behavior, as corroborated by the C–V data. These results demonstrate that nanoscale confinement, dopant-induced strain, and oxygen vacancy related defect chemistry collectively stabilize the orthorhombic ferroelectric phase, with Zr doping providing the most favorable balance between polarization strength and leakage control.

This work introduces 2-(azulen-1-yldiazenyl)-5-(thiophen-2-yl)-1,3,4-thiadiazole (L) as a functional monomer capable of forming stable, redox-active films with high affinity for lead in aqueous solutions. L was synthesized and characterized using physical chemical methods and electrochemistry. Polymer films of L were prepared through oxidative electro polymerization on glassy carbon electrodes in L solutions in 0.1 M TBAP in acetonitrile. They were characterized through electrochemistry. The surface of chemically modified electrodes (CMEs) prepared through controlled potential electrolysis (CPE) at variable concentrations, potentials, and electric charges was characterized through scanning electron spectroscopy, atomic force microscopy, and Raman spectroscopy, which confirmed the films’ formation. Electrochemical sensing of the films deposited on these CMEs was tested with respect to heavy metal (HM) ion analysis in aqueous solutions to obtain sensors for HMs. The obtained CMEs presented the best characteristics for the recognition of Pb among the investigated HMs (Cd, Pb, Cu, and Hg). Calibration curves were obtained for the analysis of Pb(II) in aqueous solutions, which allowed for the estimation of a good detection limit of this cation (<10⁻⁸ M) for non-optimized CMEs. The resulting CMEs show promise for deployment in portable environmental monitoring systems, with implications for public health protection and environmental safety.