Effects of ultrasound on the growth and function of bone and periodontal ligament cells <i>in vitro</i>

The effects of therapeutic ultrasound (US) on tissue healing processes in vivo are likely to involve US-induced changes in key cellular functions. However, these have not yet been clearly delineated and the present study has, therefore, examined the effects of a single 5-min CW exposure of 3.00-MHz US on the growth and functional activity of a human osteoblast-like cell line (MG63 cells) and human periodontal ligament (PDL) cells in vitro. Although cell proliferation was found to be largely unaffected by spatial average intensity (ISA) values of between 140–990 mW/cm2, flow cytometry (FCM) analysis showed that there were pronounced and differential effects on cell function. Thus, bone-associated proteins were down-regulated, whereas collagen type I (COL I) was unaffected and fibronectin (FN) was up-regulated at low intensities in MG63 cells. In contrast, bone protein expression was found to be dose-dependent, and FN and COL I were down-regulated in PDL cells. These results show that US has potentially important effects on the functional activities of connective tissue cells in vitro, which could markedly influence tissue repair and regeneration processes in vivo

In vitro investigation of ultrasound interaction with cells

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The Relationship between Students’ Prior Mathematical Attainment, Knowledge and Confidence on their Self-Assessment Accuracy

The ability of students to assess their own performance accurately may allow them to self-regulate their learning through metacognitive monitoring. This research investigates factors affecting undergraduate radiation physics students’ ability to self-assess their work accurately in a mathematical subject test. The factors investigated are demographics, mathematics confidence, prior mathematical attainment and prior level of mathematical knowledge. Students’ accuracy of their self-assessment was found to be associated with their prior mathematical attainment and their overall mathematics confidence. Students with good and poor prior mathematical attainment self-assessed more accurately than students who had a moderate level of prior attainment. These results have implications for how students may determine their own learning strategies and the use of summative self-assessments

Initial responses of human osteoblasts to sol–gel modified titanium with hydroxyapatite and titania composition

Sol–gel thin films of hydroxyapatite (HA) and titania (TiO2) have received a great deal of attention in the area of bioactive surface modification of titanium (Ti) implants. Sol–gel coatings were developed on Ti substrates of pure HA and TiO2 and two composite forms, HA + 10% TiO2 and HA + 20% TiO2, and the biological properties of the coatings were evaluated. All the coating layers exhibited thin and homogeneous structures and phase-pure compositions (either HA or TiO2). Primary human osteoblast cells showed good attachment, spreading and proliferation on all the sol–gel coated surfaces, with enhanced cell numbers on all the coated surfaces relative to uncoated Ti control at day 1, as observed by MTT assay and scanning electron microscopy. Cell attachment rates were also enhanced on the pure HA coating relative to control Ti. The pure HA and HA + 10% TiO2 composite coating furthermore enhanced proliferation of osteoblasts at 4 days. Moreover, the gene expression level of several osteogenic markers including bone sialoprotein and osteopontin, as measured by RT–PCR at 24 h, was shown to vary according to coating composition. These findings suggest that human primary bone cells show marked and rapid early functional changes in response to HA and TiO2 sol–gel coatings on Ti