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Antimicrobial touch surfaces have been introduced in healthcare settings with the aim of supporting existing hygiene procedures, and to help combat the increasing threat of antimicrobial resistance. However, concerns have been raised over the potential selection pressure exerted by such surfaces, which may drive the evolution and spread of antimicrobial resistance. This review highlights studies that indicate risks associated with resistance on antimicrobial surfaces by different processes, including evolution by de-novo mutation and horizontal gene transfer, and species sorting of inherently resistant bacteria dispersed on to antimicrobial surfaces. The review focuses on antimicrobial surfaces made of copper, silver and antimicrobial peptides because of the practical application of copper and silver, and the promising characteristics of antimicrobial peptides. The available data point to a potential for resistance selection and a subsequent increase in resistant strains via cross-resistance and co-resistance conferred by metal and antibiotic resistance traits. However, translational studies describing the development of resistance to antimicrobial touch surfaces in healthcare-related environments are rare, and will be needed to assess whether and how antimicrobial surfaces lead to resistance selection in these settings. Such studies will need to consider numerous variables, including the antimicrobial concentrations present in coatings, the occurrence of biofilms on surfaces, and the humidity relevant to dry-surface environments. On-site tests on the efficacy of antimicrobial coatings should routinely evaluate the risk of selection associated with their use. [ABSTRACT FROM AUTHOR]

A novel laser material BaYLuF8 (BYLF), doped with 12 at% of Tm3+, has been grown and optically investigated, in order to evaluate its potential performances as a 2 µm laser. The BYLF crystal is interesting mainly because indications are that the mixed crystal would be sturdier than BaY2F8 (BYF). The addition of lutetium would improve the thermo-mechanical properties of the host. Absorption, fluorescence and lifetime measurements have been performed in the temperature range 10–300 K focusing on the 3H4 and 3F4 manifolds, those involved in the laser scheme at 2 µm. The Stark sublevels structure of Tm3+ up to the 1D2 manifold has been figured out. Diode-pumped CW laser emission at 2 µm has been achieved obtaining a slope efficiency of about 28% with respect to the absorbed power, by pumping along the Z-axis. A maximum output power of 240 mW was achieved by pumping along the favourable Y-axis, with an incident power of about 800 mW. [ABSTRACT FROM AUTHOR]

We report the results of phonon relaxation processes obtained from picosecond transient thermoreflectance measurements of single-crystal La2CuO4+y (y∼0.06). Nonequilibrium heating was found to occur on a picosecond time scale. The time scale of the nonequilibrium heating is a sensitive measurement of the modest electron-phonon interaction (λ≤0.1) in the nonsuperconducting La2CuO4+y. [ABSTRACT FROM AUTHOR]

We report the results of a direct search for the 229Th (Iπ = 3/2+← 5/2+) nuclear isomeric transition, performed by exposing 229Th-doped LiSrAlF6 crystals to tunable vacuum-ultraviolet synchrotron radiation and observing any resulting fluorescence. We also use existing nuclear physics data to establish a range of possible transition strengths for the isomeric transition. We find no evidence for the thorium nuclear transition between 7.3 eV and 8.8 eV with transition lifetime (1-2) s ≲ τ ≲ (2000-5600) s. This measurement excludes roughly half of the favored transition search area and can be used to direct future searches. [ABSTRACT FROM AUTHOR]