Reactive Oxygen Species and Chromophoric Dissolved Organic Matter Drive the Aquatic Photochemical Pathways and Photoproducts of 6PPD-quinone under Simulated High-Latitude Conditions.

The photochemical degradation pathways of 6PPD-quinone (6PPDQ, 6PPD-Q), a toxic transformation product of the tire antiozonant 6PPD, were determined under simulated sunlight conditions typical of high-latitude surface waters. Direct photochemical degradation resulted in 6PPDQ half-lives ranging from 17.5 h at 20 °C to no observable degradation over 48 h at 4 °C. Sensitization of excited triplet-state pathways using Cs+ and Ar purging demonstrated that 6PPDQ does not decompose significantly from a triplet state relative to a singlet state. However, assessment of processes involving reactive oxygen species (ROS) quenchers and sensitizers indicated that singlet oxygen and hydroxyl radical do significantly contribute to the degradation of 6PPDQ. Investigation of these processes in natural lake waters indicated no difference in attenuation rates for direct photochemical processes at 20 °C. This suggests that direct photochemical degradation will dominate in warm waters, while indirect photochemical pathways will dominate in cold waters, involving ROS mediated by chromophoric dissolved organic matter (CDOM). Overall, the aquatic photodegradation rate of 6PPDQ will be strongly influenced by the compounding effects of environmental factors such as light screening and temperature on both direct and indirect photochemical processes. Transformation products were identified via UHPLC-Orbitrap mass spectrometry, revealing four major processes: (1) oxidation and cleavage of the quinone ring in the presence of ROS, (2) dealkylation, (3) rearrangement, and (4) deamination. These data indicate that 6PPDQ can photodegrade in cool, sunlit waters under the appropriate conditions: t1/2 = 17.4 h tono observable decrease (direct); t1/2 = 5.2-11.2 h (indirect, CDOM).

Parent Attitudes regarding Orthodontists' Role as Potential Administrators of Human Papilloma Virus (HPV) Vaccines.

Objective: To assess parent attitudes regarding orthodontists' role as potential administrators of human papilloma virus (HPV) vaccines. Materials and Methods: 275 parents of adolescents, aged 11-17, who attended the orthodontic clinic at an American university for orthodontic adjustment visits and met inclusion criteria were given information about HPV and HPV vaccines. A paper questionnaire was administered to assess comfort level with orthodontists as HPV vaccinators. Demographic and other potential explanatory characteristics were collected. Descriptive, bivariate, and multivariate ordinal logistic regression analyses were performed with SPSS statistical software v25. Results: The majority of participants were between 31 and 40 years old, with 79.6% identifying as female. 54.3% of the subjects' children identified as female. Although 71.3% of participants identified as Hispanic, 55.3% of the total participants chose to respond to the questionnaire in Spanish. 66.7% of the participants reported education level as high school degree or less. Overall, 52.4% of parents responded that they would be comfortable with orthodontists administering HPV vaccines to their children. Bivariate analysis suggested a significant association (p < 0.05) of parents taking the survey in Spanish and parents' educational attainment with HPV vaccine administration comfort level. Multivariate ordinal logistic regression indicates that parents taking survey in Spanish (adjusted OR: 2.42, 95% CI: 1.24-4.72; p < .01) and parents of male children (adjusted OR: 1.66, 95% CI: 1.01-2.73; p < 047) were comfortable with orthodontists administering the HPV vaccine. Conclusions: The language of the survey influenced parents' comfort level with orthodontists as HPV vaccinators, with Spanish having a positive correlation to comfort level. Parents of male children were more comfortable with orthodontists as HPV vaccinator.

Molecular mechanisms of phospholipase C ß3 autoinhibition.

Phospholipase C ß (PLCß) enzymes are dramatically activated by heterotrimeric G proteins. Central to this response is the robust autoinhibition of PLCß by the X-Y linker region within its catalytic core and by the Hα2' helix in the C-terminal extension of the enzyme. The molecular mechanism of each and their mutual dependence are poorly understood. Herein, it is shown that distinct regions within the X-Y linker have specific roles in regulating activity. Most important,an acidic stretch within the linker stabilizes a lid that occludes the active site, consistent with crystal structures of variants lacking this region. Inhibition by the Hα2' helix is independent of the X-Y linker and likely regulates activity by limiting membrane interaction of the catalytic core. Full activation of PLCß thus requires multiple independent molecular events induced by membrane association of the catalytic core and by the binding of regulatory proteins.