ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
SADJ : journal of the South African Dental Association = tydskrif van die Suid-Afrikaanse Tandheelkundige Vereniging, 2000
The degree of polymerisation (DP) of modern resin cements has a significant role to play in deter... more The degree of polymerisation (DP) of modern resin cements has a significant role to play in determining the ultimate physical and mechanical properties of the material. This study was undertaken to determine the DP of three adhesive resin cements, viz. 3M Opal Cement (3M), Enforce (E, Caulk/Dentsply) and C epsilon tB-Metabond (CB, Parkell). Spectra of both light-cured (3M and E) and self-cured (3M, E and CB) samples were obtained at different time intervals from 3 minutes after mixing the cement up to 24 hours, using a Dilor Raman Confocal Microprobe. The DP of the different cement specimens was calculated from the spectra and statistically analysed (ANOVA). There was a statistically significant difference (P < 0.01) between the DP of 3M and E in the two different activation modes. The light-cured specimens attained a statistically higher degree of polymerisation. CB obtained a statistically significant higher degree of polymerisation (P < 0.01) compared with 3M and E at 24 ho...
The Journal of the Dental Association of South Africa = Die Tydskrif van die Tandheelkundige Vereniging van Suid-Afrika, 1997
Highly filled luting resins are recommended for bonding porcelain restorations to tooth structure... more Highly filled luting resins are recommended for bonding porcelain restorations to tooth structure. This in vitro investigation was undertaken to determine the degree of cure of a 82 per cent filled dual-curing luting resin, after it was cured through various thicknesses of Cerec Vita Mark II porcelain. Infrared, as well as micro-Raman spectroscopy were used to determine the degree of cure of the cement at different time intervals after mixing and exposure to the curing light. The results indicated that Cerec porcelain thicknesses greater than 3 mm adversely affected the degree of cure of the luting resin, even at 24 hours after mixing the cement.
ABSTRACT Damage profiles in diamond due to implantation of argon and krypton ions at liquid nitro... more ABSTRACT Damage profiles in diamond due to implantation of argon and krypton ions at liquid nitrogen temperature were determined by α-particle channeling in a backscattering geometry. Energies and fluences were chosen to obtain similar damage energies in the surface region as obtained for a 75 keV carbon implant, investigated and discussed in a previous paper. The damage profiles before and after annealing at 1500 K were compared with those of the carbon implants. Raman spectroscopic analyses and channeling results prove that, contrary to the carbon implants, no irreversible transition to the graphitic phase takes place at comparable damage energies. Critical damage energies are obviously higher for argon and krypton ions than for the lighter carbon ions. This can be explained by a strong annealing effect of the combined inelastic energy transfer by the ion and its associated recoil atoms due to electronic stopping.
ABSTRACT In this research we studied the resonant reflection of circularly polarized light from a... more ABSTRACT In this research we studied the resonant reflection of circularly polarized light from a chiral stack of twisted ultra-thin birefringent layers such as found in the exocuticle of the beetle Proagoderus brucei. This beetle is interesting as it belongs to a very small group of species exhibiting different colors on different parts of its body. Measurements were compared with a computer model of the structure. In this way observations could be explained, some unknown parameters could be quantified and the properties of similar artificial structures with possible practical applications can be predicted.
Phosphorus, Sulfur, and Silicon and the Related Elements, 1996
IR spectroscopic studies of hydrogen bonding (intra- vs intermolecular) in selected mixed phospho... more IR spectroscopic studies of hydrogen bonding (intra- vs intermolecular) in selected mixed phosphoric-carboxylic imides (RO) 2P(O)NR′C(O)R″ 1, R = Et, R′ = H, alkyl, R″ = OEt, Ph, are presented.
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
SADJ : journal of the South African Dental Association = tydskrif van die Suid-Afrikaanse Tandheelkundige Vereniging, 2000
The degree of polymerisation (DP) of modern resin cements has a significant role to play in deter... more The degree of polymerisation (DP) of modern resin cements has a significant role to play in determining the ultimate physical and mechanical properties of the material. This study was undertaken to determine the DP of three adhesive resin cements, viz. 3M Opal Cement (3M), Enforce (E, Caulk/Dentsply) and C epsilon tB-Metabond (CB, Parkell). Spectra of both light-cured (3M and E) and self-cured (3M, E and CB) samples were obtained at different time intervals from 3 minutes after mixing the cement up to 24 hours, using a Dilor Raman Confocal Microprobe. The DP of the different cement specimens was calculated from the spectra and statistically analysed (ANOVA). There was a statistically significant difference (P < 0.01) between the DP of 3M and E in the two different activation modes. The light-cured specimens attained a statistically higher degree of polymerisation. CB obtained a statistically significant higher degree of polymerisation (P < 0.01) compared with 3M and E at 24 ho...
The Journal of the Dental Association of South Africa = Die Tydskrif van die Tandheelkundige Vereniging van Suid-Afrika, 1997
Highly filled luting resins are recommended for bonding porcelain restorations to tooth structure... more Highly filled luting resins are recommended for bonding porcelain restorations to tooth structure. This in vitro investigation was undertaken to determine the degree of cure of a 82 per cent filled dual-curing luting resin, after it was cured through various thicknesses of Cerec Vita Mark II porcelain. Infrared, as well as micro-Raman spectroscopy were used to determine the degree of cure of the cement at different time intervals after mixing and exposure to the curing light. The results indicated that Cerec porcelain thicknesses greater than 3 mm adversely affected the degree of cure of the luting resin, even at 24 hours after mixing the cement.
ABSTRACT Damage profiles in diamond due to implantation of argon and krypton ions at liquid nitro... more ABSTRACT Damage profiles in diamond due to implantation of argon and krypton ions at liquid nitrogen temperature were determined by α-particle channeling in a backscattering geometry. Energies and fluences were chosen to obtain similar damage energies in the surface region as obtained for a 75 keV carbon implant, investigated and discussed in a previous paper. The damage profiles before and after annealing at 1500 K were compared with those of the carbon implants. Raman spectroscopic analyses and channeling results prove that, contrary to the carbon implants, no irreversible transition to the graphitic phase takes place at comparable damage energies. Critical damage energies are obviously higher for argon and krypton ions than for the lighter carbon ions. This can be explained by a strong annealing effect of the combined inelastic energy transfer by the ion and its associated recoil atoms due to electronic stopping.
ABSTRACT In this research we studied the resonant reflection of circularly polarized light from a... more ABSTRACT In this research we studied the resonant reflection of circularly polarized light from a chiral stack of twisted ultra-thin birefringent layers such as found in the exocuticle of the beetle Proagoderus brucei. This beetle is interesting as it belongs to a very small group of species exhibiting different colors on different parts of its body. Measurements were compared with a computer model of the structure. In this way observations could be explained, some unknown parameters could be quantified and the properties of similar artificial structures with possible practical applications can be predicted.
Phosphorus, Sulfur, and Silicon and the Related Elements, 1996
IR spectroscopic studies of hydrogen bonding (intra- vs intermolecular) in selected mixed phospho... more IR spectroscopic studies of hydrogen bonding (intra- vs intermolecular) in selected mixed phosphoric-carboxylic imides (RO) 2P(O)NR′C(O)R″ 1, R = Et, R′ = H, alkyl, R″ = OEt, Ph, are presented.
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Papers by Linda Prinsloo