Influence of solvent evaporation on ultimate tensile strength of contemporary dental adhesives

The aim of this study was to evaluate the influence of solvent evaporation on the ultimate tensile strength (UTS) of commercial adhesives. Two 1-step(OptiBond All-In-One and G-Premio Bond) and two 2-step (Clearfil SE Protect, OptiBond XTR) adhesives were selected. Two bottles of eachadhesive were opened and stored at 37 °C in a dry oven with silica gelshielded from light for 2 weeks (“Desiccated”). Two unopened bottles were stored at room temperature (“Original”). After 2 weeks, the adhesives were used to fill an hour-glass shaped, metallic matrix mold and light-cured. Samples were weighed, and then immersed in a 37 °C water bath for 1 h or 7 days. The UTS of each sample was then measured at a cross-head speed of 1 mm/min (n = 10). The UTS for the Clearfil SE Protect was higher in the“Original” than “Desiccated” samples (p  0.05). Neither of the two “Original” 1-step samples could be hardened, even after light-curing, yet the ‘Desiccated’ OptiBond All-In-One samples obtained high UTS values. Both OptiBond All-In-One and Clearfil SE Protect had an increase in weight after the 7-day immersion in water. In conclusion, residual solvent reduces the mechanical strength of the adhesive. The hydrophilicity of the adhesive resin might also affect its mechanical strength

Journal of Electron Spectroscopy and Related Phenomena 101--103 (1999) 257--262

The magnetic linear dichroism (MLD) was used to study the magnetic properties of Ni-ultrathin film grown on ferromagnetic substrate Co(001). The MLD in photoemission has been measured for either the valence Ni3d states around the Ni3p threshold or 3p core level. Our dichroism measurements of the valence Ni3d states conclude that the resonance effect is present on MLD for `6 eV-satellite' in the valence band photoemission whereas the main valence band peak shows nearly same MLD signal for the both on and off resonance. It is shown for the thinner film that the dichroism from Ni and Co3p core levels shows same sign with each other. This means that the Ni and Co are ferromagnetically coupled. 1999 Elsevier Science B.V. All rights reserved

Comparison of the Photoinduced Orientation Structure in the Bulk and at the Near-Surface of a Photoalignable Liquid Crystalline Polymer Film

The thermally stimulated photoinduced in-plane and out-of-plane molecular reorientation behaviors of a polymethacrylate film comprised of 4-methoxycinnnamoylbiphenyl (MCB) side groups connected with a decylene spacer (PMCB10M) are compared in the bulk (>10 nm), at the inner-surface (∼10 nm), and at the near-surface (<2 nm) using polarized UV absorption and near-edge X-ray absorption fine structure (NEXAFS) spectroscopies. The biaxial reorientation characteristics in the bulk of the PMCB10 M films can be controlled by irradiating with linearly polarized (LP) UV light and subsequent annealing to generate self-organization of the MCB side groups. However, the homogeneous in-plane orientation at the near-surface, which can introduce homogeneous nematic low-molecular-weight liquid crystal mixture alignment, is observed regardless of the self-organization process. The differences in the orientation characteristics arise from long alkylene spacer and bulky mesogenic side groups