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Aim: The purpose of this study was to assess the difference of removal torque values (RTV) and the bone-to-implant contact (BIC) between the sand-blasted, large grit, and acid-etched (SLA) surface-treated and the machined surface (MA) miniscrews., Material and Methods: Miniscrews used in this study were 6mm long with a diameter of 1.5mm. A total of 23 SLA miniscrews and 24 MA miniscrews were placed into the distal femoral condyle of 24 New Zealand rabbits. Removal torque test and the BIC was histologically evaluated at 0 and 8 weeks., Results: There was no statistical difference between the RTV in the MA group versus the SLA group at both 0 and 8 weeks. Comparing 0-8 weeks, there was no significant difference in RTV of the SLA group (P = 0.48), however the change in the MA group was statistically significant (P = 0.006). Histological observation showed a significant decrease in BIC comparing 0 and 8 weeks for the MA group. The BIC ratio at 8 weeks was statistically significantly higher in the SLA group compared to the MA group., Conclusion: SLA surface preparation does not increase the RTV of miniscrews. Further investigations under loading and a large sample size are required., (© The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.) more...

Elevated concentrations of sulfide in groundwater (approximately 63 mg S(2-)/L in water and 500 mg dissolved H2S/L dissipating from the wellhead) at a field site near South Lovedale (OK, USA) were inhibiting the activity of sulfate-reducing bacteria (SRB) that are known to degrade contaminants, including benzene, toluene, ethylbenzene, and xylenes. Elevated concentrations of these contaminants, except for toluene, also were present in this groundwater. Microcosms were established in the laboratory using groundwater and sediment collected from the field site and amended with various nutrient, substrate, and inhibitor treatments. All microcosms initially were amended with FeCl2 to induce FeS precipitation and, thereby, to reduce aqueous sulfide concentrations. Complete removal of benzene, ethylbenzene, and m+p-xylenes (BEX; o-xylene not detected) was observed within 39 d in treatments with various combinations of nutrient and substrate amendments, including treatments with no amendments (other than FeCl2). This indicates that the elevated concentration of sulfide is the only limiting factor to BEX biodegradation at this site under anaerobic conditions and that treating the groundwater with FeCl2 may be a simple remedy to both facilitate and enhance BEX degradation by the indigenous SRB population. more...

The growth of acidophilic iron respiring bacteria at pH > 4.5 may be a key to the transition from acidic to circumneutral conditions that would occur during restoration of acid mine drainage sites. Flasks containing Acidiphilium cryptum ATCC 33463 were incubated initially under aerobic conditions in liquid medium containing Fe(2)(SO(4))(3) and glucose at an initial pH of 5. Significant iron respiration was observed after flasks were sealed to prevent oxygenation; at the same time, medium pH increased from 4.5 to 6. No soluble Fe(III) was detected throughout the experiments, consistent with pH conditions, indicating that bacteria were able to respire using precipitated ferric iron species. In addition, the concentration of soluble Fe(2+) reached a plateau, even though iron respiration appeared to continue, possibly due to precipitation of mixed Fe (II)/Fe(III)-oxide as magnetite. Results suggest that A. cryptum has a wide range of pH tolerance, which may enable it to play a role in controlling acid generation by means of establishing growth conditions favorable to neutrophilic bacteria such as sulfate reduction. more...