Epidemiology of HPV 16 and Cervical Cancer in Finland and the Potential Impact of Vaccination: Mathematical Modelling Analyses

BACKGROUND: Candidate human papillomavirus (HPV) vaccines have demonstrated almost 90%-100% efficacy in preventing persistent, type-specific HPV infection over 18 mo in clinical trials. If these vaccines go on to demonstrate prevention of precancerous lesions in phase III clinical trials, they will be licensed for public use in the near future. How these vaccines will be used in countries with national cervical cancer screening programmes is an important question. METHODS AND FINDINGS: We developed a transmission model of HPV 16 infection and progression to cervical cancer and calibrated it to Finnish HPV 16 seroprevalence over time. The model was used to estimate the transmission probability of the virus, to look at the effect of changes in patterns of sexual behaviour and smoking on age-specific trends in cancer incidence, and to explore the impact of HPV 16 vaccination. We estimated a high per-partnership transmission probability of HPV 16, of 0.6. The modelling analyses showed that changes in sexual behaviour and smoking accounted, in part, for the increase seen in cervical cancer incidence in 35- to 39-y-old women from 1990 to 1999. At both low (10% in opportunistic immunisation) and high (90% in a national immunisation programme) coverage of the adolescent population, vaccinating women and men had little benefit over vaccinating women alone. We estimate that vaccinating 90% of young women before sexual debut has the potential to decrease HPV type-specific (e.g., type 16) cervical cancer incidence by 91%. If older women are more likely to have persistent infections and progress to cancer, then vaccination with a duration of protection of less than 15 y could result in an older susceptible cohort and no decrease in cancer incidence. While vaccination has the potential to significantly reduce type-specific cancer incidence, its combination with screening further improves cancer prevention. CONCLUSIONS: HPV vaccination has the potential to significantly decrease HPV type-specific cervical cancer incidence. High vaccine coverage of women alone, sustained over many decades, with a long duration of vaccine-conferred protection, would have the greatest impact on type-specific cancer incidence. This level of coverage could be achieved through national coordinated programmes, with surveillance to detect cancers caused by nonvaccine oncogenic HPV types

Removal of zinc from submerged arc furnace flue gas wash water using steel slag with polyacrylamide

Abstract The aim of this research was to investigate zinc removal from submerged arc furnace flue gas wash water with steel slag and polymer treatment. The current treatment for the submerged arc furnace flue gas wash water is treatment with polymer only which aids in the settling of particulate zinc. However, in this research enhanced removal of zinc by also precipitating soluble zinc using steel slag was studied. The zinc removal results were compared with the results using commercial neutralizing agents NaOH, Mg(OH)₂, and Ca(OH)₂ together with polymer. The precipitation conditions were simulated with MINEQL + software and the calculated results were compared with the results from laboratory jar test experiments. Zinc was removed to less than the target concentration 2 mg/l with steel slag and polymer treatment at pH 9. Additionally, turbidity of the treated water decreased to 20 NTU compared to the initial 860 NTU. However, the amount of steel slag needed in the treatment was significantly higher than the amounts of NaOH and Ca(OH)₂. The main zinc removal mechanism of steel slag was precipitation as zinc oxide. Calculated zinc removal was higher than the experimental which indicates that equilibrium was not reached in the precipitation experiments which could be due to relatively short contact time chosen to simulate the actual process conditions at the plant

Success of resin infiltration treatment on interproximal tooth surfaces in young adults:a practice-based follow-up study

Abstract Objectives: Arresting active initial caries lesions is part of the modern caries controlling system. Resin infiltration (RI) system has been found a promising method in arresting interproximal initial lesions. The aim was to investigate whether RI arrests progression of active caries lesions. Materials and methods: Participants (n = 20) of the retrospective study were patients in the Dental Teaching Unit, City of Oulu, Finland, mean age 26 years (SD5.2). Indication for RI was radiographically diagnosed progressing (ICDAS 1–3) interproximal lesions (n = 54). RI treatments were performed in 2015–2017. Controls were initial lesions in the same bitewing radiographs without RI or other treatment (n = 24). For analyzes teeth were categorized as lower and upper premolars and molars. The change in lesions during the follow-up period was recorded surface wise as follows: deterioration / improvement from ICDAS score 3/improvement from ICDAS score 2/improvement per se/at follow-up, lesion was less diffuse/no change. The changes in each tooth surface were analyzed between RI intervention and control teeth by using Chi-square test. Proportions of successful and failed surfaces were given. Results: The mean length of follow-up period was 17.4 m (SD7.2). Arresting of caries lesions (ICDAS scores 2 and 3) was distinctly better in RI group (63.0%) compared with the controls (29.1%). The situation progressed among 29.2% of the controls whereas the respective proportion among the intervention group was 14.8%. Progression of lesions was more distinct in all tooth groups in the control group. Outcome was successful despite the lesion depth. Conclusions: Resin infiltration seems effective in arresting progression of initial caries lesions with monitoring period of 1.5 years