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Background The human papillomavirus (hpv) is a common sexually transmitted infection and a primary cause of cervical cancer. The Government of Canada has set a target of reaching 90% hpv vaccine coverage among adolescents by 2025. Here, we examine hpv vaccine uptake in school-based immunization programs across Canada and explore how achieving the 90% target could affect the future incidence of cervical cancer, mortality, and health system expenditures in a cohort of Canadian women. Methods Data for hpv vaccine uptake in the most recent reported school year available in each jurisdiction were provided in 2017 by jurisdictional school-based immunization programs and were used to estimate a national weighted average of 67%. The OncoSim microsimulation model (version 2.5) was used to compare 3 different levels of hpv vaccine uptake (0%, 67%, 90%) on health and economic outcomes for a hypothetical cohort of all 5- to 10-yearold girls in Canada in 2015. Results Vaccine uptake for girls in school-based programs varied from 55.0% to 92.0% in the jurisdictions reviewed. The OncoSim model projects that increasing uptake to 90% from 67% would result in a 23% reduction in cervical cancer incidence rates (to 3.1 cases from 4.0 cases per 100,000, averaged across the lifetime of the cohort) and a 23% decline in the average annual mortality rate (to 1.0 deaths from 1.3 deaths per 100,000). Finally, the model projects that the health system will incur a cost of $9 million (1% increase) during the lifetime of the cohort if uptake is increased to 90% from 67%. Costs are discounted (1.5%) and expressed in 2016 Canadian dollars. Costs reflect the payer perspective. Conclusions Our model shows that increasing hpv vaccine uptake to 90% from current levels for girls in schoolbased immunization programs could result in substantial reductions in the future incidence and mortality rates for cervical cancer in Canada. [ABSTRACT FROM AUTHOR]

The Canadian Partnership Against Cancer was created in 2007 by the federal government to accelerate cancer control across Canada. Its OncoSim microsimulation model platform, which consists of a suite of specific cancer models, was conceived as a tool to augment conventional resources for population-level policy- and decision-making. The Canadian Partnership Against Cancer manages the OncoSim program, with funding from Health Canada and model development by Statistics Canada. Microsimulation modelling allows for the detailed capture of population heterogeneity and health and demographic history over time. Extensive data from multiple Canadian sources were used as inputs or to validate the model. OncoSim has been validated through expert consultation; assessments of face validity, internal validity, and external validity; and model fit against observed data. The platform comprises three in-depth cancer models (lung, colorectal, cervical), with another in-depth model (breast) and a generalized model (25 cancers) being in development. Unique among models of its class, OncoSim is available online for public sector use free of charge. Users can customize input values and output display, and extensive user support is provided. OncoSim has been used to support decision-making at the national and jurisdictional levels. Although simulation studies are generally not included in hierarchies of evidence, they are integral to informing cancer control policy when clinical studies are not feasible. OncoSim can evaluate complex intervention scenarios for multiple cancers. Canadian decision-makers thus have a powerful tool to assess the costs, benefits, cost-effectiveness, and budgetary effects of cancer control interventions when faced with difficult choices for improvements in population health and resource allocation. [ABSTRACT FROM AUTHOR]

Background Low-dose computed tomography (LDCT) screening has been shown to reduce mortality from lung cancer; however, the optimal screening duration and "at risk" population are not known. Methods The Cancer Risk Management Model developed by Statistics Canada for the Canadian Partnership Against Cancer includes a lung screening module based on data from the U.S. National Lung Screening Trial (NLST). The base-case scenario reproduces NLST outcomes with high fidelity. The impact in Canada of annual screening on the number of incident cases and life-years gained, with a wider range of age and smoking history eligibility criteria and varied participation rates, was modelled to show the magnitude of clinical benefit nationally and by province. Life-years gained, costs (discounted and undiscounted), and resource requirements were also estimated. Results In 2014, 1.4 million Canadians were eligible for screening according to NLST criteria. Over 10 years, screening would detect 12,500 more lung cancers than the expected 268,300 and would gain 9200 life-years. The computed tomography imaging requirement of 24,000-30,000 at program initiation would rise to between 87,000 and 113,000 by the 5th year of an annual NLST-like screening program. Costs would increase from approximately $75 million to $128 million at 10 years, and the cumulative cost nationally over 10 years would approach $1 billion, partially offset by a reduction in the costs of managing advanced lung cancer. Conclusions Modelling various ways in which LDCT might be implemented provides decision-makers with estimates of the effect on clinical benefit and on resource needs that clinical trial results are unable to provide. [ABSTRACT FROM AUTHOR]

Background In Canada, discussion about changing from cytology to human papillomavirus (HPV) DNA testing for primary screening in cervical cancer is ongoing. However, the Canadian Task Force on Preventive Health Care has not yet made a recommendation, concluding that the evidence is insufficient. Methods We used the cervical cancer and HPV transmission models of the Cancer Risk Management Model to study the health and economic outcomes of primary cytology compared with HPV DNA testing in 14 screening scenarios with varying screening modalities and intervals. Projected cervical cancer cases, deaths, colposcopies, screens, costs, and incremental cost-effectiveness were evaluated. We performed sensitivity analyses for HPV DNA test costs. Results Compared with triennial cytology from age 25, 5-yearly HPV DNA screening alone from age 30 resulted in equivalent incident cases and deaths, but 55% (82,000) fewer colposcopies and 43% (1,195,000) fewer screens. At HPV DNA screening intervals of 3 years, whether alone or in an age-based sequence with cytology, screening costs are greater, but at intervals of more than 5 years, they are lower. Scenarios on the cost-effectiveness frontier were HPV DNA testing alone every 10, 7.5, 5, or 3 years, and triennial cytology starting at age 21 or 25 when combined with HPV DNA testing every 3 years. Conclusions Changing from cytology to HPV DNA testing as the primary screening test for cervical cancer would be an acceptable strategy in Canada with respect to incidence, mortality, screening and diagnostic test volumes. [ABSTRACT FROM AUTHOR]

Friction Stir Welding (FSW) is a solid-state bonding technique. There are many direct and indirect factors affecting the mechanical and microstructural properties of the FSW joints. Tool offset, tilt angle, and plunge depth are determinative tool positioning in the FSW process. Investigating the effect of these factors simultaneously with other parameters such as process speeds (rotational speed and translational speed) and tool geometry leads to a poor understanding of the impact of these factors on the FSW process. Because the three mentioned parameters have the same origin, they should be studied separately from other process parameters. This paper investigates the effects of tilt angle, plunge depth, and tool offset on Ultimate Tensile Stress (UTS) of joints between AA6061-T6 and AA7075-T6. To design the experiments, optimization, and statistical analysis, Response Surface Methodology (RSM) has been used. Experimental tests were carried out to find the maximum achievable UTS of the joint. The optimum values were determined based on the optimization procedure as 0.7 mm of tool offset, 2.7 degrees of tilt angle, and 0.1 mm of plunge depth. These values resulted in a UTS of 281 MPa. Compared to the UTS of base metals, the joint efficiency of the optimized welded sample was nearly 90 percent.

The present study investigates the effect of two parameters of process type and tool offset on tensile, microhardness, and microstructure properties of AA6061-T6 aluminum alloy joints. Three methods of Friction Stir Welding (FSW), Advancing Parallel-Friction Stir Welding (AP-FSW), and Retreating Parallel-Friction Stir Welding (RP-FSW) were used. In addition, four modes of 0.5, 1, 1.5, and 2 mm of tool offset were used in two welding passes in AP-FSW and RP-FSW processes. Based on the results, it was found that the mechanical properties of welded specimens with AP-FSW and RP-FSW techniques experience significant increments compared to FSW specimens. The best mechanical and microstructural properties were observed in the samples welded by RP-FSW, AP-FSW, and FSW methods, respectively. Welded specimens with the RP-FSW technique had better mechanical properties than other specimens due to the concentration of material flow in the weld nugget and proper microstructure refinement. In both AP-FSW and RP-FSW processes, by increasing the tool offset to 1.5 mm, joint efficiency increased significantly. The highest weld strength was found for welded specimens by RP-FSW and AP-FSW processes with a 1.5 mm tool offset. The peak sample of the RP-FSW process (1.5 mm offset) had the closest mechanical properties to the base metal, in which the Yield Stress (YS), ultimate tensile strength (UTS), and elongation percentage (E%) were 76.4%, 86.5%, and 70% of base metal, respectively. In the welding area, RP-FSW specimens had smaller average grain size and higher hardness values than AP-FSW specimens.

This article investigates the flow of materials and weld formation during underwater friction stir welding (UFSW) of low carbon steel. A thermo-mechanical model is used to understand the relation between frictional heat phenomena during the welding and weld properties. To better understand the effects of the water environment, the simulation and experimental results were compared with the sample prepared by the traditional friction stir welding (FSW) method. Simulation results from surface heat diffusion indicate a smaller preheated area in front of the FSW tool declined the total generated heat in the UFSWed case compared to the FSWed sample. The simulation results revealed that the strain rate of steel in the stir zone (SZ) of the FSWed joint is higher than in the UFSWed case. The microstructure of the welded sample shows that SZ's microstructure at the UFSWed case is more refined than the FSWed case due to the higher cooling rate of the water environment. Due to obtained results, the maximum temperatures of FSWed and UFSWed cases were 1228 °C and 1008 °C. Meanwhile, the simulation results show 1200 °C and 970 °C for conventional and underwater FSW samples, respectively. The maximum material velocity in SZ predicted 0.40 m/s and 0.32 m/s for FSW and underwater FSWed samples. The better condition in the UFSW case caused the ultimate tensile strength of welded sample to increase ~20% compared to the FSW joint.

One of the main challenging issues in friction stir welding (FSW) of stiffened structures is maximizing skin and flange mixing. Among the various parameters in FSW that can affect the quality of mixing between skin and flange is tool plunge depth (TPD). In this research, the effects of TPD during FSW of an Al-Mg-Si alloy T-joint are investigated. The computational fluid dynamics (CFD) method can help understand TPD effects on FSW of the T-joint structure. For this reason, the CFD method is employed in the simulation of heat generation, heat distribution, material flow, and defect formation during welding processes at various TPD. CFD is a powerful method that can simulate phenomena during the mixing of flange and skin that are hard to assess experimentally. For the evaluation of FSW joints, macrostructure visualization is carried out. Simulation results showed that at higher TPD, more frictional heat is generated and causes the formation of a bigger stir zone. The temperature distribution is antisymmetric to the welding line, and the concentration of heat on the advancing side (AS) is more than the retreating side (RS). Simulation results from viscosity changes and material velocity study on the stir zone indicated that the possibility of the formation of a tunnel defect on the skin-flange interface at the RS is very high. Material flow and defect formation are very sensitive to TPD. Low TPD creates internal defects with incomplete mixing of skin and flange, and high TPD forms surface flash. Higher TPD increases frictional heat and axial force that diminish the mixing of skin and flange in this joint. The optimum TPD was selected due to the best materials flow and final mechanical properties of joints.

Research on T-configuration aluminum constructions effectively decreases fuel consumption, increases strength, and develops aerial structures. In this research, the effects of friction stir welding (FSW) tool offset (TO) on Al-Mg-Si alloy mixing and bonding in T-configurations is studied. The process is simulated by the computational fluid dynamic (CFD) technique to better understand the material mixing flow and the bonding between the skin and flange during FSW. According to the results, the best material flow can be only achieved at an appropriate TO. The appropriate TO generates enough material to fill the joint line and results in formation of the highest participation of the flange in the stir zone (SZ) area. The results show that, in the T-configuration, FSW joints provide raw materials from the retreating side (RS) of the flange that play a primary role in producing a sound mixing flow. The selected parameters were related to the geometric limitations of the raw sheets considered in this study. The failure point of all tensile samples was located on the flange. Surface tunneling is the primary defect in these joints, which is produced at high TOs. Among the analyzed cases, the most robust joint was made at +0.2 mm TO on the advancing side (AS), resulting in more than 60% strength of the base aluminum alloy being retained.