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Alumina is a material that has been used in both dental and orthopedic applications. It is with these uses in mind that osteoblast (bone-forming cell) function on alumina of varying particulate size, chemistry, and phase was tested in order to determine what formulation might be the most beneficial for bone regeneration. Specifically, in vitro osteoblast adhesion, proliferation, intracellular alkaline phosphatase activity, and calcium deposition was observed on delta-phase nanospherical, alpha-phase conventional spherical, and boehmite nanofiber alumina. Results showed for the first time increased osteoblast functions on the nanofiber alumina. Specifically, a 16% increase in osteoblast adhesion over nanophase spherical alumina and a 97% increase over conventional spherical alumina were found for nanofiber alumina after 2 h. A 29% increase in cell number after 5 days and up to a 57% greater amount of calcium was found on the surface of the nanofiber alumina compared with other alumina surfaces. Some of the possible explanations for such enhanced osteoblast behavior on nanofiber alumina may be attributed to chemistry, crystalline phase, and topography. Increased osteoblast function on nanofiber alumina suggests that it may be an ideal material for use in orthopedic and dental applications.

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Journal of Aerosol Science 40 (2009) 65-71. doi:10.1016/j.jaerosci.2008.09.003Received by publisher: 2008-03-22Harvest Date: 2016-01-04 12:19:58DOI: 10.1016/j.jaerosci.2008.09.003Page Range: 65-7

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The surface tension of sodium, potassium, rubidium, and cesium was measured by a maximum-bubble-pressure method at temperatures ranging from the melting point to 1000°C. in a cobalt-tungsten alloy (L-605) chamber. Surface tensiontemperature regression lines with standard deviations of 2.5% were derived from the data. The results are compared with those of other investigators and used to determine total surface energy and parachor. A general relationship between surface tension and atomic radius is derived.Recent technological advances have yielded increased applications for the alkali metals. An accurate knowledge of the physical properties of these fluids has become vital in many of these applications. One such property, surface tension, is important in wettability and migration effects as well as in atomic bonding studies and in correlation studies with other thermophysical properties. Surface tension values are also utilized in two-phase heat transfer computations.The surface tension of each of four alkali metals-sodium, potassium, rubidium, and cesium-was determined experimentally between the melting point and 1000°C. These results were used to derive the parachor, the total surface energy, and a relationship between surface tension and atomic radius.EXPERIMENTAL METHOD Surface tension values were determined by measuring the maximum pressure required to form and liberate argonfilled bubbles from vertical capillary tubes immersed in the liquid metal. The maximum pressure (i*max) required to liberate an inert gas bubble from a tube tip may be expressed as the sum of two component pressures, one of which is related directly to surface tension, as shown below:Pmax

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