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In atomic force microscopy, the cantilever probe is a critical component whose properties determine the resolution and speed at which images with nanoscale resolution can be obtained. Traditional cantilevers, which have moderate resonant frequencies and high quality factors, have relatively long response times and low bandwidths. In addition, cantilevers can be easily damaged by excessive deformation, and tips can be damaged by wear, requiring them to be replaced frequently. To address these issues, new cantilever probes that have hollow cross-sections and walls of nanoscale thicknesses made of alumina deposited by atomic layer deposition are introduced. It is demonstrated that the probes exhibit spring constants up to ≈100 times lower and bandwidths up to ≈50 times higher in air than their typical solid counterparts, allowing them to react to topography changes more quickly. Moreover, it is shown that the enhanced robustness of the hollow cantilevers enables them to withstand large bending displacements more readily and to be more resistant to tip wear.

The purpose of this study was to quantify the ultraviolet B (UVB) output and in vitro previtamin D3 synthesis over time from various artificial light sources. Three incandescent lamps, T-Rex Active UVHeat 160 watt spot, T-Rex Active UVHeat 160 watt flood, and ZooMed PowerSun 160 watt flood, and two 1.2 m fluorescent lamps, Sylvania Blacklight 350 BL and ZooMed Reptisun 5.0, were studied. Total UVB irradiance and concentration of previtamin D synthesized using an in vitro ampoule model were quantified initially and at monthly intervals for 1 year. Incandescent lamps were measured at distances of 0.9 and 1.5 m while fluorescent lamps were measured at distances of 30.5 and 45.7 cm at the lamp's center, using both the radiometer and ampoules. Fluorescent lamp irradiance was also measured at the lamp's ends. Data were analyzed as a repeated measures split-plot in time using SAS with all mean differences determined using Least Squares Means. Incandescent lamp irradiance differences were seen at various distances. The UVHeat lamps had consistently higher previtamin D3 production and irradiance readings compared with the PowerSun lamp. Reptisun 5.0 was consistently higher in UVB irradiance over Sylvania BL 350 at both 30.5 and 45.7 cm. However, there were no differences when comparing conversion of 7-dehydrocholesterol to previtamin D3. Irradiance differences were detected between the centers and ends of the fluorescent lamps. Until UVB requirements for vitamin D3 synthesis in animals are determined, it is impossible to state that one light is superior to another. Zoo Biol 29:741–752, 2010. © 2010 Wiley-Liss, Inc.