Risk factors for nonmelanoma skin cancer in renal transplant recipients: a case-control study from a reference outpatient clinic in Southeast Brazil

BackgroundNonmelanoma skin cancer (NMSC) is the most common tumor in humans, and its incidence increases among renal transplant recipients (RTRs). The aims of this study were to characterize the RTRs with NMSC, to identify risk factors, and to calculate the probability of this tumor in this population. MethodsThis was a hospital-based case-control study. Epidemiological and clinical variables were evaluated. Hierarchical logistic regression was used, and a mathematical model was built. ResultsIn total, 245 subjects were included. Possible associations were identified using a univariate analysis. Multivariate analysis identified risk factors with respective odds ratios and confidence intervals (95% CI): males 2.5 (1.3-4.7), age over 50years 5.4 (2.3-12.9), Fitzpatrick's skin phototypes I-III 3.7 (1.6-8.7), occupational sun exposure 4.1 (2.1-8.1), timetable of recreational sun exposure all day 3.0 (1.4-6.1), and duration of transplantation (80months or more) 3.3 (1.6-6.5). The Hosmer-Lemeshow test and the receiver operating characteristics curve showed a strong fit and accuracy, respectively. The probability of an NMSC ranged from less than 1 to 92.5%. ConclusionsThis study characterized the RTRs with NMSC and identified risk factors. The multivariate analysis by hierarchical logistic regression proved to be a useful tool and allowed for the determination of the probability of NMSC in this population.University of TaubateUniv Taubate UNITAU, Dept Med, Taubate, BrazilFed Univ Sao Paulo UNIFESP, Dept Dermatol, Sao Paulo, BrazilFed Univ Sao Paulo UNIFESP, Dept Dermatol, Sao Paulo, BrazilWeb of Scienc

Solid State Effects on Exciton States and Optical Properties of PPV

We perform ab initio calculations of optical properties for a typical semiconductor conjugated polymer, poly-para-phenylenevinylene, in both isolated chain and crystalline packing. In order to obtain results for excitonic energies and real-space wave functions we explicitly include electron-hole interaction within the density-matrix formalism. We find that the details of crystalline arrangement crucially affect the optical properties, leading to a richer exciton structure and opening nonradiative decay channels. This has implications for the optical activity and optoelectronic applications of polymer films