Journal of Electron Spectroscopy and Related Phenomena
Core (1s and 2~) X-ray photoelectron shifts and KLL (ID?) Auger shifts for 22 sulfur compounds ha... more Core (1s and 2~) X-ray photoelectron shifts and KLL (ID?) Auger shifts for 22 sulfur compounds have been measured. The values have been correlated by means of atomic charge plus remote potential or central atom potential models. Either approach is equally effective for binding energy correlations. The relaxation corrected and transition state models are in general superior to ground state models. Auger shift predictions are however poor in all cases. Absolute total static relaxation and extra-atomic relaxation values have been assessed by using the Auger parameter of Lang and Wiiams and relativistic atomic calculations for the free atom and its ions. Theee extra-atomic relaxation components are not additive but rather obey an average contribution behavior. The relaxation shift values have been compared with those obtained from the original Auger parameter (a) of Wagner. The correlation of 1s and 2p binding energies suggested a revised relationship for the Wagner Auger parameter and an equivalent simple form of the Lang and Williams parameter which can be used with satisfactory results when only the usual experimental binding energy (2~) is available in conjunction with the Auger shift.
Journal of Vacuum Science & Technology A Vacuum Surfaces and Films
Remote plasma‐enhanced chemical vapor deposition of using a radio‐frequency (rf) Ar/ plasma and d... more Remote plasma‐enhanced chemical vapor deposition of using a radio‐frequency (rf) Ar/ plasma and downstream‐injected was investigated. The deposition rate at 20 W rf power was measured as a function of pressure, temperature, and flow rate. The deposition rate at 300°C and ...
Sodium hypochlorite (NaOCl), chelating agents, and chlorhexidine (CHX), which are commonly used i... more Sodium hypochlorite (NaOCl), chelating agents, and chlorhexidine (CHX), which are commonly used irrigants during endodontic treatment, have the potential to alter the physical and chemical properties of the dentin structure. The aim of this study was to use time-of-flight secondary ion mass spectrometry to qualitatively evaluate the chemical characteristics of dentin surface and compare it with dentin exposed to NaOCl, EDTA, or CHX. Four blocks of dentin from a root of a human maxillary molar were embedded in resin and trimmed with a microtome to expose the dentin. Samples were randomly assigned to 4 treatment groups: (1) no irrigation treatment (sample A), (2) 2.5% NaOCl (sample B), (3) 17% EDTA (sample C), and (4) 2% CHX (sample D). Dentin surfaces were analyzed by time-of-flight secondary ion mass spectrometry, which allowed characterization of dentin surface chemistry by both imaging and mass spectroscopic analysis obtained in high mass and spatial resolution modes. Sample A revealed intense peaks characteristics of hydroxyapatite in addition to Na(+), K(+), CH4N(+), CN(-), CNO(-), Mg(+), F(-), and HCO2(-) peaks. Sample B showed severely decreased CH4N(+) and increased intensity of Cl(-). Sample C lacked Ca(+) and Mg(+) and showed decreased PO2(-) and PO3(-). Sample D exhibited a distinct presence of CHX. The spectral image of sample A displayed even distribution of Na(+) and Ca(+) on a smeared surface. The surfaces of samples B and D had patent dentinal tubules, whereas sample D showed an intense CHX signal. Sample C had some patent dentinal tubules and lacked Ca(+). NaOCl removed protein components from the dentin matrix, EDTA removed calcium and magnesium ions from the dentin, and CHX formed an adsorbed layer on the dentin surface.
Journal of the Chemical Society, Chemical Communications, 1993
When heated at 500 °C under nitrogen the poly(ferrocenylsilanes)[Fe( -C 5 H 4 ) 2 (SiR 2 )] n (1;... more When heated at 500 °C under nitrogen the poly(ferrocenylsilanes)[Fe( -C 5 H 4 ) 2 (SiR 2 )] n (1; R = Me, or 2; R = Ph) yield magnetic iron silicon carbide ceramics together with a orangeyellow sublimate which, in the case of 1, was shown to contain the unusual ...
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has emerged as one of the most importan... more Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has emerged as one of the most important and versatile surface analytical techniques available for advanced materials research. This arises from its excellent mass resolution, sensitivity and high spatial resolution providing both chemical and distributional (laterally and depth) information for a wide variety of materials and applications. Understanding the various modes of operation and the information that each provides is crucial to the analyst in order to optimise the type of data that is obtained. New developments in primary ion sources and the application of multivariate analysis techniques, which can only extend the versatility and applicability of the technique, are also discussed.
Interaction of sodium hypochlorite (NaOCl) mixed with chlorhexidine (CHX) produces a brown precip... more Interaction of sodium hypochlorite (NaOCl) mixed with chlorhexidine (CHX) produces a brown precipitate containing para-chloroaniline (PCA). When QMiX is mixed with NaOCl, no precipitate forms, but color change occurs. The aim of this study was to qualitatively assess the formation of precipitate and PCA on the surface and in the tubules of dentin irrigated with NaOCl, followed either by EDTA, NaOCl, and CHX or by saline and QMiX by using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Dentin blocks were obtained from human maxillary molars, embedded in resin, and cross-sectioned to expose dentin. Specimens in group 1 were immersed in 2.5% NaOCl, followed by 17% EDTA, 2.5% NaOCl, and 2% CHX. Specimens in group 2 were immersed in 2.5% NaOCl, followed by saline and QMiX. The dentin surfaces were subjected to TOF-SIMS spectra analysis. Longitudinal sections of dentin blocks were then exposed and subjected to TOF-SIMS analysis. All samples and analysis were performed in triplicate for confirmation. TOF-SIMS analysis of group 1 revealed an irregular precipitate, containing PCA and CHX breakdown products, on the dentin surfaces, occluding and extending into the tubules. In TOF-SIMS analysis of group 2, no precipitates, including PCA, were detected on the dentin surface or in the tubules. Within the limitations of this study, precipitate containing PCA was formed in the tubules of dentin irrigated with NaOCl followed by CHX. No precipitates or PCA were detected in the tubules of dentin irrigated with NaOCl followed by saline and QMiX.
Introduction: The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in t... more Introduction: The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in the formation of a precipitate. In a previous study, we demonstrated the formation of 4-chloroaniline (PCA) in the precipitate by using x-ray photon spectroscopy (XPS) and time of flight secondary ion mass spectrometry (TOF-SIMS). The TOF-SIMS results showed a peak at 127 amu, which is characteristic of 4-chloroaniline. However, this could also be characteristic of other isomers of 4-chloroaniline such as 2-chloroaniline and 3-chloroaniline. Aims and Methods: The aim of this study was to further identify the precipitate by using gas chromatography-mass spectrometry (GC-MS). Results: The results showed an absence of other aniline derivatives in the precipitate. Only PCA was found. Conclusions: Further investigations of the precipitate should address the bioavailability of PCA leaching out from dentin and its cytotoxicity. Until the precipitate is studied further, it would appear prudent to minimize its formation by avoiding the use of CHX together with NaOCl. (J Endod 2010;36:312-314)
The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in the formation o... more The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in the formation of a precipitate. The aim of this study was to determine the minimum concentration of NaOCl required to form a precipitate with 2.0% CHX. This was accomplished with a serial dilution technique. X-ray photon spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) were used to qualify and quantify the precipitate. A color change and precipitate were induced in 2.0% CHX by 0.023 % and 0.19 % NaOCl, respectively. Both XPS and TOF-SIMS showed the presence of para-chloroaniline in an amount directly related to the concentration of NaOCl used. Until this precipitate is studied further, its formation should be avoided by removing the NaOCl before placing CHX into the canal. (J Endod 2007;33:966 -969)
ABSTRACT Primary rat bone marrow cells were cultured on bacteriological grade polystyrene dishes ... more ABSTRACT Primary rat bone marrow cells were cultured on bacteriological grade polystyrene dishes which had been treated in selected areas with concentrated sulphuric acid. X-ray photoelectron spectroscopy, angle-resolved and imaging modes, and atomic force microscopy showed that the acid treatment brought about both chemical and topographical changes in the substratum surface. While the bone marrow cells attached to both treated and untreated areas of the surfaces of the dishes, the distribution of early mineralized extracellular matrix in these areas was reproducibily different. Thus, using extracellular matrix deposition as a marker, modification of the polymer surface resulted in the cells adhering to treated and untreated areas exhibiting different phenotypes.
ABSTRACT The nature of adhesion in multicomponent materials such as cellulosic fibers/thermoplast... more ABSTRACT The nature of adhesion in multicomponent materials such as cellulosic fibers/thermoplastic composites is strongly dependent on the surface properties of the components. X-ray Photoelectron Spectroscopy (XPS) was used to characterize the surfaces of untreated and treated newsprint-fibers. Gamma-aminopropyltriethoxysilane and dichlorodiethylsilane were used for the surface modification of the fibers. The XPS analysis indicated that coupling between the silanes and the newsprint-fibers has occurred, and that silanols were adsorbed to the surface of newsprint-fibers by two different mechanisms: (1) an ether linkage between the silanols and the hydroxyl groups of the fibers and (2) a hydrogen bonding between the amine and the hydroxyl groups of the fibers. The formation of the hydrogen bonding was evidenced by the two observed amino states, i.e., a covalent non-protonated form and an ionic protonated form.
X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy techniq... more X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy techniques were used to study the surface chemical compositions of cellulosic ®bers before and after treatments. The ®bers were treated with phthalic anhydride and maleated polypropylene for surface modi®cations. Both XPS and FTIR spectroscopy analysis indicated that chemical bonds between hydroxyl groups of cellulosic ®bers and anhydride moieties of phthalic anhydride and maleated polypropylene have occurred through esteri®cation reaction. These chemical reagents have been added to the surface of cellulosic ®bers in the form of monoester, i.e., the formation of esteri®ed cellulosic ®bers bearing a pendent carboxylic group.
Journal of Electron Spectroscopy and Related Phenomena
Core (1s and 2~) X-ray photoelectron shifts and KLL (ID?) Auger shifts for 22 sulfur compounds ha... more Core (1s and 2~) X-ray photoelectron shifts and KLL (ID?) Auger shifts for 22 sulfur compounds have been measured. The values have been correlated by means of atomic charge plus remote potential or central atom potential models. Either approach is equally effective for binding energy correlations. The relaxation corrected and transition state models are in general superior to ground state models. Auger shift predictions are however poor in all cases. Absolute total static relaxation and extra-atomic relaxation values have been assessed by using the Auger parameter of Lang and Wiiams and relativistic atomic calculations for the free atom and its ions. Theee extra-atomic relaxation components are not additive but rather obey an average contribution behavior. The relaxation shift values have been compared with those obtained from the original Auger parameter (a) of Wagner. The correlation of 1s and 2p binding energies suggested a revised relationship for the Wagner Auger parameter and an equivalent simple form of the Lang and Williams parameter which can be used with satisfactory results when only the usual experimental binding energy (2~) is available in conjunction with the Auger shift.
Journal of Vacuum Science & Technology A Vacuum Surfaces and Films
Remote plasma‐enhanced chemical vapor deposition of using a radio‐frequency (rf) Ar/ plasma and d... more Remote plasma‐enhanced chemical vapor deposition of using a radio‐frequency (rf) Ar/ plasma and downstream‐injected was investigated. The deposition rate at 20 W rf power was measured as a function of pressure, temperature, and flow rate. The deposition rate at 300°C and ...
Sodium hypochlorite (NaOCl), chelating agents, and chlorhexidine (CHX), which are commonly used i... more Sodium hypochlorite (NaOCl), chelating agents, and chlorhexidine (CHX), which are commonly used irrigants during endodontic treatment, have the potential to alter the physical and chemical properties of the dentin structure. The aim of this study was to use time-of-flight secondary ion mass spectrometry to qualitatively evaluate the chemical characteristics of dentin surface and compare it with dentin exposed to NaOCl, EDTA, or CHX. Four blocks of dentin from a root of a human maxillary molar were embedded in resin and trimmed with a microtome to expose the dentin. Samples were randomly assigned to 4 treatment groups: (1) no irrigation treatment (sample A), (2) 2.5% NaOCl (sample B), (3) 17% EDTA (sample C), and (4) 2% CHX (sample D). Dentin surfaces were analyzed by time-of-flight secondary ion mass spectrometry, which allowed characterization of dentin surface chemistry by both imaging and mass spectroscopic analysis obtained in high mass and spatial resolution modes. Sample A revealed intense peaks characteristics of hydroxyapatite in addition to Na(+), K(+), CH4N(+), CN(-), CNO(-), Mg(+), F(-), and HCO2(-) peaks. Sample B showed severely decreased CH4N(+) and increased intensity of Cl(-). Sample C lacked Ca(+) and Mg(+) and showed decreased PO2(-) and PO3(-). Sample D exhibited a distinct presence of CHX. The spectral image of sample A displayed even distribution of Na(+) and Ca(+) on a smeared surface. The surfaces of samples B and D had patent dentinal tubules, whereas sample D showed an intense CHX signal. Sample C had some patent dentinal tubules and lacked Ca(+). NaOCl removed protein components from the dentin matrix, EDTA removed calcium and magnesium ions from the dentin, and CHX formed an adsorbed layer on the dentin surface.
Journal of the Chemical Society, Chemical Communications, 1993
When heated at 500 °C under nitrogen the poly(ferrocenylsilanes)[Fe( -C 5 H 4 ) 2 (SiR 2 )] n (1;... more When heated at 500 °C under nitrogen the poly(ferrocenylsilanes)[Fe( -C 5 H 4 ) 2 (SiR 2 )] n (1; R = Me, or 2; R = Ph) yield magnetic iron silicon carbide ceramics together with a orangeyellow sublimate which, in the case of 1, was shown to contain the unusual ...
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has emerged as one of the most importan... more Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has emerged as one of the most important and versatile surface analytical techniques available for advanced materials research. This arises from its excellent mass resolution, sensitivity and high spatial resolution providing both chemical and distributional (laterally and depth) information for a wide variety of materials and applications. Understanding the various modes of operation and the information that each provides is crucial to the analyst in order to optimise the type of data that is obtained. New developments in primary ion sources and the application of multivariate analysis techniques, which can only extend the versatility and applicability of the technique, are also discussed.
Interaction of sodium hypochlorite (NaOCl) mixed with chlorhexidine (CHX) produces a brown precip... more Interaction of sodium hypochlorite (NaOCl) mixed with chlorhexidine (CHX) produces a brown precipitate containing para-chloroaniline (PCA). When QMiX is mixed with NaOCl, no precipitate forms, but color change occurs. The aim of this study was to qualitatively assess the formation of precipitate and PCA on the surface and in the tubules of dentin irrigated with NaOCl, followed either by EDTA, NaOCl, and CHX or by saline and QMiX by using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Dentin blocks were obtained from human maxillary molars, embedded in resin, and cross-sectioned to expose dentin. Specimens in group 1 were immersed in 2.5% NaOCl, followed by 17% EDTA, 2.5% NaOCl, and 2% CHX. Specimens in group 2 were immersed in 2.5% NaOCl, followed by saline and QMiX. The dentin surfaces were subjected to TOF-SIMS spectra analysis. Longitudinal sections of dentin blocks were then exposed and subjected to TOF-SIMS analysis. All samples and analysis were performed in triplicate for confirmation. TOF-SIMS analysis of group 1 revealed an irregular precipitate, containing PCA and CHX breakdown products, on the dentin surfaces, occluding and extending into the tubules. In TOF-SIMS analysis of group 2, no precipitates, including PCA, were detected on the dentin surface or in the tubules. Within the limitations of this study, precipitate containing PCA was formed in the tubules of dentin irrigated with NaOCl followed by CHX. No precipitates or PCA were detected in the tubules of dentin irrigated with NaOCl followed by saline and QMiX.
Introduction: The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in t... more Introduction: The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in the formation of a precipitate. In a previous study, we demonstrated the formation of 4-chloroaniline (PCA) in the precipitate by using x-ray photon spectroscopy (XPS) and time of flight secondary ion mass spectrometry (TOF-SIMS). The TOF-SIMS results showed a peak at 127 amu, which is characteristic of 4-chloroaniline. However, this could also be characteristic of other isomers of 4-chloroaniline such as 2-chloroaniline and 3-chloroaniline. Aims and Methods: The aim of this study was to further identify the precipitate by using gas chromatography-mass spectrometry (GC-MS). Results: The results showed an absence of other aniline derivatives in the precipitate. Only PCA was found. Conclusions: Further investigations of the precipitate should address the bioavailability of PCA leaching out from dentin and its cytotoxicity. Until the precipitate is studied further, it would appear prudent to minimize its formation by avoiding the use of CHX together with NaOCl. (J Endod 2010;36:312-314)
The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in the formation o... more The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in the formation of a precipitate. The aim of this study was to determine the minimum concentration of NaOCl required to form a precipitate with 2.0% CHX. This was accomplished with a serial dilution technique. X-ray photon spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) were used to qualify and quantify the precipitate. A color change and precipitate were induced in 2.0% CHX by 0.023 % and 0.19 % NaOCl, respectively. Both XPS and TOF-SIMS showed the presence of para-chloroaniline in an amount directly related to the concentration of NaOCl used. Until this precipitate is studied further, its formation should be avoided by removing the NaOCl before placing CHX into the canal. (J Endod 2007;33:966 -969)
ABSTRACT Primary rat bone marrow cells were cultured on bacteriological grade polystyrene dishes ... more ABSTRACT Primary rat bone marrow cells were cultured on bacteriological grade polystyrene dishes which had been treated in selected areas with concentrated sulphuric acid. X-ray photoelectron spectroscopy, angle-resolved and imaging modes, and atomic force microscopy showed that the acid treatment brought about both chemical and topographical changes in the substratum surface. While the bone marrow cells attached to both treated and untreated areas of the surfaces of the dishes, the distribution of early mineralized extracellular matrix in these areas was reproducibily different. Thus, using extracellular matrix deposition as a marker, modification of the polymer surface resulted in the cells adhering to treated and untreated areas exhibiting different phenotypes.
ABSTRACT The nature of adhesion in multicomponent materials such as cellulosic fibers/thermoplast... more ABSTRACT The nature of adhesion in multicomponent materials such as cellulosic fibers/thermoplastic composites is strongly dependent on the surface properties of the components. X-ray Photoelectron Spectroscopy (XPS) was used to characterize the surfaces of untreated and treated newsprint-fibers. Gamma-aminopropyltriethoxysilane and dichlorodiethylsilane were used for the surface modification of the fibers. The XPS analysis indicated that coupling between the silanes and the newsprint-fibers has occurred, and that silanols were adsorbed to the surface of newsprint-fibers by two different mechanisms: (1) an ether linkage between the silanols and the hydroxyl groups of the fibers and (2) a hydrogen bonding between the amine and the hydroxyl groups of the fibers. The formation of the hydrogen bonding was evidenced by the two observed amino states, i.e., a covalent non-protonated form and an ionic protonated form.
X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy techniq... more X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy techniques were used to study the surface chemical compositions of cellulosic ®bers before and after treatments. The ®bers were treated with phthalic anhydride and maleated polypropylene for surface modi®cations. Both XPS and FTIR spectroscopy analysis indicated that chemical bonds between hydroxyl groups of cellulosic ®bers and anhydride moieties of phthalic anhydride and maleated polypropylene have occurred through esteri®cation reaction. These chemical reagents have been added to the surface of cellulosic ®bers in the form of monoester, i.e., the formation of esteri®ed cellulosic ®bers bearing a pendent carboxylic group.
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