Background and objectives: Inflammatory bowel disease (IBD) is associated with an increased risk of developing colorectal cancer as well as some extra-intestinal tumors, but there are still limited data about the risk of prostate cancer (PC). To analyze if there is an increased risk of PC in patients affected by IBD, we performed a systematic review with meta-analysis. Materials and Methods: A Pubmed search of all studies comparing standardized incidence ratio (SIR) or odds ratio (OR) or relative risks (RR) of PC between IBD and non IBD groups, published until March 2020 was conducted. The study protocol was registered on PROSPERO. Twelve studies, mostly population studies, were included. The quality score of these studies, evaluated by the Newcastle–Ottawa Scale, was 7. The heterogeneity was high among the studies in which ulcerative colitis (UC) was considered separate from Crohn’s disease (CD) and in the studies that considered UC and CD together (“IBD-studies”), while it was low in the studies which considered CD separate from UC. Results: The relative risk of developing PC was 1.71 (95% confidence interval [CI] 1.16–2.51, p = 0.007) in IBD, 1.10 (95%CI 0.98–1.25, p = 0.116) in CD, and 1.22 (95%CI 0.98–1.51, p = 0.07) in UC. Conclusions: Patients with IBD appear to have a slightly increased risk of PC compared to the general population.
The control of the Group Velocity Dispersion ( GVD) in the waveguiding structures may be of crucial interest in optical communications. It may be achieved controlling one of the components of GVD, the waveguide dispersion, which depends on the geometry and the refractive index profiles of the guiding structures. In this paper the waveguide dispersion in practical guiding structures is evaluated by means of a general numerical procedure, based on a FEM formulation and a second order perturbation of the corresponding eigenvalue equation. The evaluation is performed for various values of geometrical and phisycal parameters of the guiding structures, in order to seek for a best structures configuration, in which waveguide dispersion may compensate the dispersive effects of the optical materials in a given frequency range. Particular attention has been devoted to the possibility to control the sign of GVD in the single mode region which is of great concern for the design of all optical components..
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