Background: Recent data have demonstrated increased lipid peroxidation (LPO) levels and oxidative stress in periodontitis. Malondialdehyde (MDA) and superoxide dismutase (SOD) are both increased during oxidative stress. Furthermore, this study examined SOD concentration, total oxidative status (TOS) and MDA levels in periodontal patients and investigated the longitudinal effect of periodontal therapy on the index levels of chronic periodontitis (CP) patients. Methods: Serum, saliva and gingival crevicular fluid (GCF) samples were obtained from 48 CP patients and 35 healthy control subjects prior to, as well as after 16 weeks following non-surgical post-periodontal therapy. MDA, TOS and SOD and clinical parameters were determined pre-and post-therapy. Results: The levels of TOS and SOD values were significantly higher in the CP group than in the control group (p < 0.05), but only MDA in GCF. Post-periodontal therapy, serum, saliva and GCF TOS and SOD levels significantly decreased compared to basal levels (p < 0.05), but only MDA in GCF. Conclusions: LPO was higher in the periodontal region, with TOS and SOD increasing both locally and peripherally. Nonsurgical therapy can restore and control the subject antioxidant capacity by locally and systemically modifying the levels of MDA, TOS and SOD.

Often, the sources of polycyclic aromatic hydrocarbons (PAHs) in environmental media can be identified by comparing the ratios of concentrations of selected pairs of PAH congeners in the source emissions to the ratios in the contaminated environmental media. However, these ratios can be altered significantly due to differences in the transport of the PAH compounds in a multimedia environment. To examine such changes, a fugacity model was applied to PAH ratios in a model environment. A linear relationship between the rate of emission and the bulk media concentration was identified for each PAH compound in an environmental medium at steady state and was quantified by a receptor-to-source ratio (RRS). It was demonstrated that the RRS values of the two congeners usually differ significantly. Consequentially, PAH ratios changed remarkably from the source emissions to various environmental media. A site-specific rectification factor (RF) was defined as the ratio of the two RRS values of the paired congeners for a specific PAH ratio in a given medium, which can be applied to account for the ratio changes in a multimedia environment. The PAH ratio changes were further verified with the surface soil data collected from Tianjin, China, and the observed changes of PAH ratios were compared favorably with the model predictions. The sensitivity analysis revealed that PAH ratios of the low molecular weight compounds were less stable. The most influential parameters controlling PAH ratios were those pertaining to dry precipitation, surface-to-air diffusion, degradation in air and water, and exchange between water and sediment.

Both TPTPS and SD4 are due to duplications involving ZRS, the limb specific SHH enhancer. Point mutations in the ZRS and duplications encompassing the ZRS cause distinctive limb phenotypes.

This paper proposes a new method to investigate the effect of specimen size on fatigue life of metallic materials in high‐cycle fatigue and very‐high‐cycle fatigue regimes in the light of statistical analysis. The performance of large specimen is correlated with that of small specimen via control volume (a high stress domain where potential fatigue crack initiation sites are located). The simulation results are in good agreement with a series of experimental data in high‐cycle fatigue and very‐high‐cycle fatigue regimes from literature. The method is helpful for a quantitative estimation of fatigue life of large specimens from the experimental data of small specimens.