Background/Objectives: Prevention of biofilm formation by bacteria is of critical importance to areas that directly affect human health and life including medicine, dentistry, food processing and water treatment. This work showcases an effective and affordable solution for reducing attachment and biofilm formation by several pathogenic bacteria commonly associated with foodborne illnesses and medical infections. Methods: Our approach exploits anodisation to create alumina surfaces with cylindrical nanopores with diameters ranging from 15 to 100 nm, perpendicular to the surface. The anodic surfaces were evaluated for attachment by Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Staphylococcus epidermidis. Cell–surface interaction forces were calculated and related to attachment. Results: We found that anodic alumina surfaces with pore diameters of 15 and 25 nm were able to effectively minimise bacterial attachment or biofilm formation by all the microorganisms tested. Using a predictive physicochemical approach on the basis of the extended Derjaguin and Landau, Verwey and Overbeek (XDLVO) theory, we attributed the observed effects largely to the repulsive forces, primarily electrostatic and acid–base forces, which were greatly enhanced by the large surface area originating from the high density, small-diameter pores. We also demonstrate how this predictive approach could be used to optimise different elements of surface topography, particularly pore diameter and density, for further enhancing the observed bacteria-repelling effects. Conclusions: We demonstrate that anodic nanoporous surfaces can effectively reduce bacterial attachment. These findings are expected to have immediate, far-reaching implications and commercial applications, primarily in health care and the food industry.

This work presents the fabrication and characterization of mechanical and magnetic properties of polydimethylsiloxane (PDMS) nanocomposites with nickel nanoparticles and nanowires as fillers. To enhance filler dispersion and polymer-filler interface bonding, allyltrimethoxysilane was used for nanofiller coating. Sample preparation was carried out by speed mixing and curing at $100°\text{C}$ . Nanowire-PDMS composites were exposed to magnetic field prior to full curing in order to facilitate nanowire alignment. Composites with concentrations of 5, 10, and 15 vol % of nanoparticles and 5 vol % of nanowires were prepared and tested. An increase in elastic modulus of $\sim 30\%$ was observed for composites with 5 vol % nanoparticle concentration. A much higher increase in elastic modulus, of $\sim 80\%$ , was observed for nanowire-based composites of same concentration. The measured elastic modulus agrees well with predictions that assume strong interface bonding between the polymer and the filler. Magnetic anisotropy and higher remanent magnetization and coercivity are observed for the nanowire composite. These multifunctional materials could have a wide range of applications, from active structural components to sensing elements in macro- and particularly microsystem applications.

This paper explores energy dissipation in ex vivo liver tissue during radiofrequency current excitation with application in electrosurgery. Tissue surface temperature for monopolar electrode configuration is measured using infrared thermometry. The experimental results are fitted to a finite-element model for transient heat transfer taking into account energy storage and conduction in order to extract information about “apparent” specific heat, which encompasses storage and phase change. The average apparent specific heat determined for low temperatures is in agreement with published data. However, at temperatures approaching the boiling point of water, apparent specific heat increases by a factor of five, indicating that vaporization plays an important role in the energy dissipation through latent heat loss.

This paper reports on the dynamic characteristics of a MEMS electrostatic harvester employing interdigitated gap-closing topology. Devices are fabricated using SOIMUMPS technology and are characterized with and without biasing voltages for a broad range of excitation accelerations. At low vibration amplitudes the presence of a dc bias causes the resonant frequency peak to shift to lower frequencies with increasing bias. At higher vibration amplitudes the dynamic response of the devices exhibits the behavior of a Duffing oscillator with spring softening due to nonlinear stiffness attributed to the effect of electrostatic forces. Specifically, the devices exhibit sweep direction hysteresis with jump phenomena due to the multivaluedness of the response curve. Amplitude sweeps at constant frequency and varying bias voltage also show jump phenomena, highlighting how slight differences in operating conditions dramatically affect device performance. Spring hardening effects are reported for devices contaminated with dust particles. The paper also discusses SOIMUMPS limitations, the importance of reducing off-axis vibration during testing, characterization methods, and the effect of grounding on parasitic capacitance.