Controlling the distribution of the Mn12–stearate, single-molecule magnets (SMMs) anchored on a select surface is expected to be a new method for tuning its interactions, and an investigation on the magnetic properties of separated magnetic molecules is also lacking. The anchoring of the SMMs at the surface with an assumed statistic distance between each other is not an easy task; nevertheless, in this work, we show a synthesis which allows for this in detail. The immobilization of the Mn12–stearate was demonstrated with the use of FTO glasses and spherical silica as substrates. Based on differential pulse anodic stripping voltammetry (DPASV) and transmission electron microscopy (TEM) observations, we proved the efficiency of the method proposed. We observed continuous decreasing the number of bonds, and afterward, decreasing in the number of immobilized molecules with an increasing the number of spacer units used for separation of the magnetic particles.

The Helmholtz wave equation is derived for longitudinal waves in an elastic plate of arbitrary thickness placed in a rigid gantry ensuring a constant width. The whole range of Poisson's ratio allowed for isotropic elastic media constrained in this way is considered. The wave speed is shown to increase under a constant longitudinal compressive stress applied to the front face of the plate and to decrease when the applied stress is tensile. The effect is most pronounced for zero Poisson's ratio and it vanishes for the limiting permitted values, i.e., 1 or À1. The reported results also describe the combined effect of longitudinal stress and Poisson's ratio on the wave speed. These findings provide guidelines for designing devices aimed at a passive control of propagation of longitudinal waves in thin-walled structures.

The purpose of this numerical study, performed within the micromagnetic framework and the dynamical matrix method, is to understand how the propagation of spin waves in a macrospin chain is affected by a configurational rearrangement of the magnetization, induced by a progressive variation of a magnetic field. Our macrospins are modelized through thin cylinders with elliptical cross sections that display a monodomain, bistable magnetization distribution; hence, the allowed magnetization configurations of the chain are either antiferromagnetic (AF) or ferromagnetic (FM). We illustrate the peculiar features of spin waves in the AF and FM configurations concerning the dispersion relations, phase amplitude variations and localization, and precession ellipticity, as a function of the applied field, particularly close to the critical field values at which the configurational rearrangements occur (AF-to-FM or vice versa). A remarkable effect that arises on the mode frequency and bandwidth across a configurational transition is the frequency invariance of specific Bloch waves, particularly attractive for processing the spin wave signals in low dissipation magnon-spintronic devices.

In this article, we describe the antimicrobial properties of a new composite based on anodic aluminium oxide (AAO) membranes containing propyl-copper-phosphonate units arranged at a predetermined density inside the AAO channels. The samples were prepared with four concentrations of copper ions and tested as antimicrobial drug on four different strains of Escherichia coli (K12, R2, R3 and R4). For comparison, the same strains were tested with three types of antibiotics using the minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests. Moreover, DNA was isolated from the analysed bacteria which was additionally digested with formamidopyrimidine-DNA glycosylase (Fpg) protein from the group of repair glycosases. These enzymes are markers of modified oxidised bases in nucleic acids produced during oxidative stress in cells. Preliminary cellular studies, MIC and MBC tests and digestion with Fpg protein after modification of bacterial DNA suggest that these compounds may have greater potential as antibacterial agents than antibiotics such as ciprofloxacin, bleomycin and cloxacillin. The described composites are highly specific for the analysed model Escherichia coli strains and may be used in the future as new substitutes for commonly used antibiotics in clinical and nosocomial infections in the progressing pandemic era. The results show much stronger antibacterial properties of the functionalised membranes on the action of bacterial membranes in comparison to the antibiotics in the Fpg digestion experiment. This is most likely due to the strong induction of oxidative stress in the cell through the breakdown of the analysed bacterial DNA. We have also observed that the intermolecular distances between the functional units play an important role for the antimicrobial properties of the used material. Hence, we utilised the idea of the 2D solvent to tailor them.