The aim of this work is to develop a physical model to describe the evolution of the apparent contact angle for four different liquids on nanotextured alumina surfaces with different pore radius. The nanoporous alumina templates were fabricated by anodization of Al foil in a 0.3 M oxalic acid solution. Scanning electron microscopy was used to characterize the morphology of the surfaces. The templates are approximately 400 nm in thickness and consist of a well-ordered hexagonal array of uniform radius pores spaced 105 nm apart with pore radii from 12 to 42 nm. The wettability of nanoporous alumina templates was investigated using contact-angle measurements. We measured the contact angles using four liquids: water, ethylene glycol, aniline, and a mixture of ethylene glycol and aniline. We developed a new theoretical model for the contact angle on nanoporous surfaces as a function of the pore radius. This model is based on energy considerations and involves liquid penetration into the nanopores driven by the capillarity (Laplace's law). Because the air is compressed inside the pores, this model also includes the effect of the line tension. This is important because the three-phase line length is greatly enhanced in our nanoporous structures. For example: for a millimeter-sized droplet, the three-phase line around the perimeter of the droplet is a few millimeters long, whereas the total three-phase line within the pores can reach several tens of meters. Using our model, the line-tension value for our nanopore samples is positive and ranges from 4 to 13 × 10(-9) N, which falls within the wide interval from 10(-11) to 10(-5) N quoted in the literature. Nanoporous surfaces may allow the effect of line tension to be visible for micro- to macrodroplets.

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In this work, we modified the topography of commercial titanium orthopedic screws using electrochemical anodization in a 0.4 wt% hydrofluoric acid solution to produce titanium dioxide nanotube layers. The morphology of the nanotube layers were characterized using scanning electron microscopy. The mechanical properties of the nanotube layers were investigated by screwing and unscrewing an anodized screw into several different types of human bone while the torsional force applied to the screwdriver was measured using a torque screwdriver. The range of torsional force applied to the screwdriver was between 5 and 80 cN Á m. Independent assessment of the mechanical properties of the same surfaces was performed on simple anodized titanium foils using a triboindenter. Results showed that the fabricated nanotube layers can resist mechanical stresses close to those found in clinical situations.

<p><strong>After cell adhesion processes in microcosm, the impact of sodium hypochlorite (NaOCl) and hydrogen peroxide (H₂O₂) on the detachment of <em>Enterococcus faecalis </em>from polythene fragments immersed in water under stationary and dynamic conditions was assessed. The abundance of planktonic cells was also evaluated. The density of <em>E. faecalis</em> adhered in absence of disinfectant fluctuated between 2 and 4 units (Log CFU/cm²). </strong><strong>After living in disinfected water, </strong><strong>the density of <em>E. faecalis</em> remained adhered to polythene sometimes reached 2 units (Log CFU/Cm²)</strong><strong>. </strong><strong>This highest abundance of cells remained adhered was recorded with cells coming from the lag, exponential and stationary growth phases in water treated with 0.5‰ NaOCl. In H₂O₂ disinfected water, the highest value was recorded at all cells growth phases with 5‰ H₂O₂concentration. Adhered <em>E. faecalis</em> cells have been sometimes completely or partially decimated respectively by NaOCl and H₂O₂ treated water. Considering separately each experimental condition, it was noted that increasing the concentration of disinfectant caused a significant decrease (P≤0.01) in abundance of cells stay adhered after living in water disinfected by the two disinfectants. Changes in disinfectant concentrations in different experimental conditions had an impact on the detachment of <em>E. faecalis</em> cells from the substrates. </strong></p>