PubMed · 4862357
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
H Kushida. 1964. Improved methods for embedding with Durcupan.. https://pubmed.ncbi.nlm.nih.gov/4862357/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
We used chemical force microscopy (CFM) to study adhesive forces between surfaces of epoxy resin and self-assembled monolayers (SAMs) capable of hydrogen bonding to different extents. The influence of the liquid medium in which the experiments were carried out was also examined systematically. The molecular character of the tip, polymer, and liquid all influenced the adhesion. Complementary macroscopic contact angle measurements were used to assist in the quantitative interpretation of the CFM data. A direct correlation between surface free energy and adhesion forces was observed in mixed alcohol-water solvents. An increase in surface energy from 2 to 50 mJ/m(2) resulted in an increase in adhesion from 4-8 nN to 150-300 nN for tips with radii of 50-150 nm. The interfacial surface energy for identical nonpolar surface groups of SAMs was found not to exceed 2 mJ/m(2). An analysis of adhesion data suggests that the solvent was fully excluded from the zone of contact between functional groups on the tip and sample. With a nonpolar SAM, the force of adhesion increased monotonically in mixed solvents of higher water content; whereas, with a polar SAM (one having a hydrogen bonding component), higher water content led to decreased adhesion. The intermolecular force components theory was used for the interpretation of adhesion force measurements in polar solvents. Competition between hydrogen bonding within the solvent and hydrogen bonding of surface groups and the solvent was shown to provide the main contribution to adhesion forces. We demonstrate how the trends in the magnitude of the adhesion forces for chemically heterogeneous systems (solvents and surfaces) measured with CFM can be quantitatively rationalized using the surface tension components approach. For epoxy polymer, inelastic deformations also contributed heavily to measured adhesion forces.
Deresining must be performed for HE, specific histochemical staining and immunohistochemical detection on semithin-sections embedded-epoxy resin. The deresining process in general methods had to take 24 hours, and the semithin-sections were easily separated from slides. An improved method was introduced in this paper, by which deresining time was only 5 minutes, and it could also avoid the separation of semithin-sections from the slides. The staining result was very good, and the resolving power of images was high.
AIM: To examine formaldehyde release from three different root-canal sealers: one phenol resin, one epoxy resin and one paraformaldehyde containing zinc oxide eugenol cement. METHODOLOGY: Formaldehyde was measured from freshly mixed material and from specimens allowed to set for 2 days or 2 weeks. Different mixing ratios and sample sizes were tested. Analysis was performed by reacting formaldehyde with acetylacetone and ammonia to form diacetyldihydrolutidine, which was revealed by spectrophotometry. RESULTS: Analysis revealed that mixing ratio, time after mixing and surface:weight ratios of specimens had different influences on the formaldehyde release from different materials. CONCLUSIONS: From the results of this study it is difficult to define a standardized in-vitro test that can be applied universally for the definitive determination of formaldehyde release from endodontic sealers. Prediction of in-vivo formaldehyde release from endodontic sealers is difficult.