Effect of well-dispersed surface-modified silica nanoparticles on crystallization behavior of poly (lactic acid) under compressed carbon dioxide

The final publication is available at Elsevier via https://doi.org/10.1016/j.polymer.2016.06.019. © 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/In this work, the crystallization behavior of poly (lactic acid) (PLA)/amine-modified silica nano- composites at different loadings of amine-modified silica (1, 2, and 8 wt %) under isothermal, non- isothermal, and isothermal under compressed CO2 is studied. A significant improvement in crystalliza- tion rate was observed after introduction of the nanoparticles. A modified Hoffman-Lauritzen nucleation theory was utilized to explain the facilitation and acceleration of the crystallization process of nano- composites with introducing the surface energy of the nanoparticles and interfacial energy between polymer/nanoparticle into the rate equation. After incorporation of the nanoparticles, three-dimensional spherulites formed sporadically in the PLA matrix based on the prediction of the Avrami exponents of the nanocomposites. High-pressure DSC results also showed an increase in the crystallization rate at 15 bar compared with the atmospheric pressure condition. However, an increase in pressure up to 21 bar had no significant effect on the crystallization rate. The PLA nanocomposites with lower molecular weights and D-content also showed a significant increase in the crystallization rate but with no change in the crys- tallization mechanism.Natural Sciences and Engineering Research Council (NSERC) of Canada || Network for Innovative Plastic Materials and Manufacturing Processes (NIPMMP) || Ontario Centers of Excellence || Canada Research Chairs (CRC)

Twenty-Year Trends in the Incidence and revalence of Diagnosed Anogenital Warts in Canada

Background: A vaccine has recently been licensed in many countries that protects against the human papillomavirus types 6,11,16, and 18. Types 6 and 11 account for approximately 90% of anogenital warts (AGWs). We describe the 20-year trends in the incidence and prevalence of AGWs in Manitoba, Canada. Methods: We used linked population-based hospital and physician databases for Manitoba for 1984 to 2004. Cases were identified using tariff (billing) and ICD codes. A case was considered to be incident if it was preceded by a 12-month interval free period of AGWs care. Otherwise, it was deemed to be prevalent. An episode was considered over once a 12-month interval had elapsed without an AGW claim. Results: Approximately 25,000 Manitobans were diagnosed with AGWs between 1985 and 2004. The annual age-standardized incidence rates peaked in 1992 (men, 149.9/100,000; women 170.8/100,000). In recent years, the rates have been increasing again, particularly for men. The male:female incidence rate ratio increased from 0.76 in 1985 to 1.25 in 2004. The highest incidence rate tended to be in those aged 20 to 24 years. Trends in prevalence were similar. Prevalence in 2004 was 165.2/100,000 for men and 128.4/100,000 for women. Conclusions: These population-based findings suggest that AGWs are a substantial burden to Manitobans and that their pattern has changed over time, with incidence and prevalence becoming higher in men than women. Monitoring the future trends in AGWs will provide an early marker of the effectiveness and duration of protection of human papillomavirus vaccination at a population level