Natural zeolites have great potential as nutrient carriers to develop eco-efficient materials for massive use in agriculture. Zeolitic minerals usually contain only one dominant zeolite type. The use of minerals with mixtures of zeolites in similar proportions can affect the interaction of chemical species with the zeolitic matrix, altering the behaviour of the resulting materials. In this work, a mineral consisting mainly of a mixture of two zeolites, mordenite (MOR) and clinoptilolite-heulandite (HEU) with equivalent fractions, was used to develop materials carrying nutrients (N, P, and K) for agricultural crops. The mineral matrix provides important elements such as K and Si, while N and P were incorporated into the material by treatment with ammonium hydrogenphosphate and urea. The presence of superficially adsorbed PO4 3-, NH4 + exchanged in zeolites, and urea arranged on the surface so that it covers the material and interacts with the zeolitic frameworks, was evidenced by Fourier-transform IR spectroscopy, adsorption measurements, scanning electron microscopy, scanning transmission electron microscopy, and other methods, as well as through culture tests. The complexity of the multiphase zeolitic support leads to changes in the position and intensity of FTIR bands compared to other similar materials developed using simpler zeolitic carriers dominated by HEU zeolite. The most intense NH4 + band was observed at 1402 cm-1, while for a HEU zeolite it was at 1540 cm-1. This difference was associated with a higher NH4 + content in MOR compared to HEU. Accordingly, the shift experienced by the urea amino group bands when it interacts with the frameworks of these zeolites is different. The applied treatments did not affect the structures (as evidenced by XRD) and other qualities of these zeolites, highlighting their ion-exchange and adsorption properties for nutrient release and reversible water retention. This is essential for the use of this material as a slow-release fertilizer that efficiently provides nutrients for the agroecological development of plants, as evidenced in the cultivation tests.

In this work, the high-frequency response of a multiwalled carbon nanotube (MWCNT) film grown on a silicon substrate is compared with that of MWCNT sponges (CNSs). Different from the CNT film, CNSs are a self-standing material that can operate in the absence of a supporting substrate, showing high flexibility, light weight, and mechanical robustness. We tested our synthesized CNSs as active material for the production of antennas working in the radio frequency (RF) range to determine whether CNT sponges present, in addition to practical advantages over CNT films, also an actual performance gain. The antenna built from CNSs shows an enhanced response gain compared with that of the MWCNT film, with both antennas having a maximum positioned around 4.8 GHz. After identifying the best CNT-based sample, the experiment focused on improving the CNS antenna's response. In particular, we observed that the response of S 11 = -22.6 dB around 4.8 GHz from the CNS antenna improved after a mild treatment with ethanol, reaching S11 = -32.6 dB measured after 10 min of waiting. This observed effect is studied in detail with scanning electron microscopy and Raman spectroscopy, which point to significant modifications of the CNS's inner morphology after the treatment. Signal reception tests simulating real-world operation conditions were also carried out at two different distances to evaluate the practical application of the CNS as RF antennas. The ethanol treatment was also applied for these tests, and an increase in the response up to 45% was found for the two studied positions.

Atomic force microscopy using Si cantilevers provides an effective means for investigating both conservative and dissipative interactions in the vertical and lateral directions between the tip and the sample. An accurate evaluation of the dynamic stiffness of the cantilever is indispensable in the quantitative analyses of the interactions. We calculated the dynamic stiffness of cantilevers under torsional oscillation based on the strain energy. Without tips, the torsional dynamic stiffness is approximately 23% larger than the static stiffness. The modification decreases to 21–23% with tips. Applying the present correction is essential for achieving quantitatively accurate stiffness values in dynamic measurements.

An in-depth analysis of Abrikosov vortex dynamics and flux-flow instabilities was performed in NbRe/Au and NbRe/Py bilayers to compare superconducting/normal metal (S/N) and superconducting/ferromagnetic (S/F) heterostructures based on the same superconducting layer. The heterostructures, fabricated by sputtering, were characterized through electrical transport measurements. The I–V characteristics show that, in the NbRe/Py bilayer, vortices reach higher critical velocities than those observed in the NbRe/Au structure. The analysis of the flux-flow instability within the Larkin–Ovchinnikov framework allows one to extract the quasiparticle energy relaxation time. For external magnetic field values for which edge barrier pinning is dominant and thermal effects are negligible, the relaxation times are about 150 ps and 24 ps for NbRe/Au and NbRe/Py bilayers, respectively. These results indicate that NbRe/Py bilayers, having a relaxation time one order of magnitude smaller than values reported in NbRe microbridges, have great potential for the realization of devices where fast relaxation processes are required.

Local anodic oxidation (LAO), also known as local oxidation nanolithography or oxidation scanning probe lithography has emerged as a versatile technique for nanoscale patterning, leveraging the precision of scanning probe microscopy, relying specifically on atomic force microscopy. This review explores the materials utilized in LAO experiments, including semiconductors, metals, insulators, two-dimensional (2D) materials, and emerging heterostructures. Semiconductors such as silicon and silicon carbide remain foundational due to their controllable oxidation kinetics, while metals like titanium and aluminum offer opportunities for plasmonic and optical applications. 2D materials, including graphene, graphene oxide, and transition metal dichalcogenides, demonstrate unique oxidation behaviors, enabling high-resolution applications in electronics and quantum devices. Recent advancements, such as electrode-free LAO, have expanded the range of applicable materials and improved the precision and scalability of the process. This paper also aims to provide a comprehensive understanding of material selection in LAO and its implications for advancing nanotechnology.

Nanoparticle-based functionalization has emerged as an effective strategy to enhance the antimicrobial properties of textiles. In this study, silver (Ag+), copper (Cu2+), and zinc (Zn2+) cations are ion-exchanged with Y-type zeolite (CBV-600) and subsequently applied to cotton fabrics using the pad–dry–cure method, with an acrylic resin serving as binder. The resulting functionalized fabrics, containing metal cation concentrations of 1.0–1.5 atom % are evaluated regarding their antimicrobial activity against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative), as well as regarding their physicochemical and mechanical properties. Scanning electron microscopy confirms the uniform distribution and successful incorporation of nanomaterials onto the fabric surfaces. Antimicrobial tests reveal significant inhibition of bacterial growth, with silver-based materials demonstrating superior efficacy. Importantly, the antimicrobial effect persists after five washing cycles, demonstrating the durability of the functionalization. This method demonstrates a simple and industry-compatible approach for producing durable antimicrobial cotton fabrics.

In this work, we present the design, fabrication, and study of the optical properties of multilayered metal–dielectric Au/TiO2 structures. The samples were fabricated using Joule effect evaporation for gold and electron beam evaporation for titanium dioxide. Their structure was designed to have an epsilon-near-zero (ENZ) point at different wavelengths around 800 nm, in order to study their nonlinear response as a function of the resonance conditions around the ENZ point. The characterization of the linear properties of the samples was done using spectrophotometry and spectral ellipsometry. We studied the nonlinear response with the z-scan technique at different incident irradiances using a Ti:sapphire femtosecond laser, enabling us to characterize both the refractive and absorptive contributions to the nonlinear response. Due to the high pulse repetition rate inherent to Ti:sapphire systems and the presence of linear absorption in the samples, cumulative pulse-to-pulse thermal effects may be present. A modified version of the z-scan technique that allowed us to separate the electronic from the thermal contribution was used. A clear enhancement of the nonlinear response was observed for the sample with an ENZ point around the laser wavelength 800 nm with a nonlinear refractive index of n2 = 0.103 ± 0.006 cm2·GW−1, a value that is comparable to other ENZ materials in literature.

Wood tracheids and fibers exhibit diverse structures and shapes across plant species. The hierarchical structure and composition of cellulose, hemicelluloses, and lignin enables wood to withstand high stress. This structural resilience makes wood a versatile material for applications ranging from construction to advanced composites. However, a detailed understanding of how delignification affects softwood tracheid and hardwood fiber morphology is crucial for predicting material behavior and developing modified wood products. This study investigated the overall structural changes due to delignification, in five wood species, namely, spruce, beech, balsa, Douglas fir, and poplar. It additionally provides detailed morphology of delignified single tracheids and fibers. Scanning electron microscopy was used to compare the morphology between untreated and delignified fibers and tracheids. X-ray tomography enabled us to reconstruct high-resolution 3D models of delignified single tracheids or fibers, providing information on the pit arrangements. Moreover, delignification resulted in facilitated separation of fibers and tracheids and frayed wall appearance. We observed similar tracheid/fiber diameters and wall thicknesses for all five wood species. These findings enhance our understanding of the wood fiber and tracheid structures across species and the effects of delignification. The 3D models provide a valuable resource for (1) understanding interspecies differences of fibers and tracheids, (2) optimizing the use of delignified wood in industrial applications (including bio-based and bio-inspired materials), and (3) physical modeling of wood regarding questions of wood biomechanics and water management.

Gold nanoparticles (AuNPs) supported on reduced graphene oxide (AuNPs/rGO) were demonstrated to be a highly reactive catalyst for the selective α,β-oxidative dehydrogenation (ODH) of N-alkyl-4-piperidones, using N-methyl-, N-ethyl- and N-benzyl-4-piperidone. The substrate N-methyl-4-piperidone represents a pharmaceutically relevant system as its reaction product N-methyl-2,3-dihydropyridin-4(1H)-one is highly valuable (>1000 €·g−1) in contrast to the inexpensive starting material (0.15 €·g−1). Various synthesis methods were employed to prepare AuNPs supported on different carbon materials, including reduced graphene oxide (rGO), activated carbon (AC), and carbon black (CB), to investigate the influence of the carbon support on the catalyst performance. As stabilizing agents for the AuNPs, citrate (Cit) and the polyoxometallate [SiW9O34]10− (SiW9) were used. Among the tested catalysts, the rGO-supported ones, Au-Cit/rGO, Au-SiW9/rGO, and Au@SiW9/rGO exhibited the highest catalytic activity for the selective oxidation reaction despite containing the lowest gold loading. These findings highlight the exceptional performance of rGO as a support for AuNP catalysts and provide valuable insights for designing efficient Au-based systems for the dehydrogenation of β-N-substituted saturated ketones and other fine chemical applications.