In oil sand industry, formation of a stable salty water-in-diluted bitumen emulsion poses a serious corrosion problem at the bitumen upgrading plant. Previous studies indicated the presence of a "critical concentration" of bitumen in the emulsion, above which the oil-water interface is flexible and the water-in-diluted bitumen emulsion is stable, but below which the interface becomes rigid and the emulsion is unstable. The cause of this critical concentration was investigated through isolation and characterization of the interfacial material from the emulsions both below and above the critical concentration. The analytical data showed that, in heptane/ toluene(1:1)-diluted bitumen emulsions, the flexible interfacial film is composed of a mixture of asphaltene and carboxylic salts with a combined H/C ratio of 1.32 while the rigid interfacial film is composed of asphaltene alone with a H/C ratio of 1.13. The carboxylic salts are water insoluble and are likely sodium naphthenates containing >20 carbons. The presence of sodium naphthenates might hinder the conformational change of asphaltene at the interface, necessary for rigid film formation.

By means of electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and automated field desorption/ionization (FD) FT-ICR MS, we identify nonvolatile nonpolar, polar acidic, and basic water-in-bitumen emulsion film stabilizers. Highly condensed aromatic basic, nonpolar, and acidic asphaltene multilayered films stabilize emulsions near or at critical bitumen concentration for asphaltene flocculation. Solvent diluent added beyond the critical dilution concentration precipitates highly condensed acidic, all basic, and most neutral species from the oil/water interface. The most abundant classes in high bitumen concentration emulsion films include neutral pure hydrocarbons and S, acidic O 2 and O 2 S, and basic N and NS heteroatom classes. Highly abundant low bitumen concentration emulsion film stabilizers include acidic O 2 , O 4 , and O 3 S classes.

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By means of electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT−ICR MS), we identify nonvolatile polar acidic and basic emulsion stabilizers in nine geographically distinct light, medium, and heavy oils. Although oil class distributions are unique, oils of similar API specific gravity exhibit similar relative abundances for the O2 and O4S classes. Heavy oils are high in O2 and low in low in O4S. The light oils follow the opposite trend. However, independent of parent oil O2 and O4S class abundances, O2 and O4S species preferentially adsorb and are the two most abundant classes in the emulsion interfacial material. Negative-ion nitrogen-containing classes do not have a high affinity for emulsion interface adsorption. However all positive-ion nitrogen-containing species adsorb to the oil/water interface.

Selective serotonin reuptake inhibitors (SSRIs), the most widely used drugs for the treatment of depression, have been reported to reduce bone formation and increase the risk of bone fracture. Since osseointegration is influenced by bone metabolism, this study aimed to investigate the association between SSRIs and the risk of failures in osseointegrated implants. This retrospective cohort study was conducted on patients treated with dental implants from January 2007 to January 2013. A total of 916 dental implants in 490 patients (94 implants on 51 patients using SSRIs) were used to estimate the risk of failure associated with the use of SSRIs. Data analysis involved Cox proportional hazards, generalized estimating equation models, multilevel mixed effects parametric survival analysis, and Kaplan-Meier analysis. After 3 to 67 mo of follow-up, 38 dental implants failed and 784 succeeded in the nonusers group, while 10 failed and 84 succeeded in the SSRI-users group. The main limitation of this retrospective study was that drug compliance dose and treatment period could not be acquired from the files of the patients. The primary outcome was that compared with nonusers of SSRIs, SSRI usage was associated with an increased risk of dental implants failure (hazard ratio, 6.28; 95% confidence interval, 1.25-31.61; p = .03). The failure rates were 4.6% for SSRI nonusers and 10.6% for SSRI users. The secondary outcomes were that small implant diameters (≤4 mm; p = .02) and smoking habits (p = .01) also seemed to be associated with higher risk of implant failure. Our findings indicate that treatment with SSRIs is associated with an increased failure risk of osseointegrated implants, which might suggest a careful surgical treatment planning for SSRI users.