30 research outputs found
Gas Solubility, Diffusivity, Permeability, and Selectivity in Mixed Matrix Membranes Based on PIM-1 and Fumed Silica
No full textThe effects of adding fumed silica (FS) nanoparticles on the gas permeability, solubility, diffusivity and selectivity of a polymer of intrinsic microporosity (PIM-1) are modeled considering the density of the composite matrix as the key input information. PIM-1 is treated as a homogeneous glassy polymer endowed with a specific free volume that increases with the amount of nanoparticles loaded, as indicated by the experimental values of mixed matrix density. The solubility isotherms of H2, He, O2, N2, CH4 and CO2 in matrices of PIM-1 with different FS loadings are calculated with the Nonequilibrium Lattice Fluid (NELF) model. The gas diffusivity and permeability variation due to FS addition are related to the fractional free volume of the polymer phase according to the semiempirical free volume theory equation. Remarkably, the coefficient amplifying the free volume effect increases with the molecular size of the gas, expressed by the van der Waals volume, thus allowing to estimate the transport properties of gases not investigated experimentally, such as methane. The behavior inspected differs from the one observed in Mixed Matrix Membranes (MMM) formed by PIM-1 and porous selective fillers, that show higher selectivity towards smaller penetrants than the pure polymer, because the effect of silica nanoparticles is only represented by an enhancement of the large free volume domains. The model allows to estimate the ideal selectivity together with its solubility and diffusivity contributions, at various FS contents, for several gas pairs (O2/N2, CO2/N2, CO2/CH4, CO2/H2), which are then compared to the experimental trends available
“Women’s Studies e studi di genere all’Università di Bologna. Un bilancio e prospettive per il futuro”
No full textLa prevenzione nella popolazione femminile: dal progetto "quattro stagioni" al progetto "Benessere Donna".
No full textThe prevalence of contact sensitivity to several permanent hair dyes [Prevalenza della sensibilizzazione da contatto ad alcuni coloranti permanenti per capelli]
No full textPrevalenza della sensibilizzazione da contatto ad alcuni coloranti permanenti per capelli
No full textBackground: permanent hair dyes are a common cause of allergic contact dermatitis (ACD) in hairdressers and their clients. The sale of these products has progressively decreased in recent years, despite their improved quality and safety. Objectives: the aims of this study were to determine a) the present prevalence of contact sensitivity to p-phenylenediamine (PPD), p-toluenediamine (PTD) and disperse orange 3 (DO3), b) the trend of concomitant or cross reactions to these three dyes, and c) the possible use of PTD and/or DO3 as an alternative to PPD. Materials and methods: 8,573 consecutive patients affected by eczematous dermatitis were patch tested with PTD sulphate, DO3, PPD free base (each 1% in pet.) and the other allergens of the SIDAPA standard series according to the GIRDCA guidelines. The results were statistically analysed. Results and conclusions: allergic reactions to one or more hair dyes were observed in 318 subjects (3.7%). PPD were positive in 307 (3.6%), DO3 in 121 (1...
Wastewater network challenges and solutions
No full textSewer and storm water systems in cities worldwide suffer from ageing and inappropriate wastewater networks. This challenge has to be met by systematic upgrading and preventive maintenance. It is necessary to analyse the current performance of the wastewater networks, to determine the system bottlenecks that cause system vulnerability on floods in city areas and pollution of receiving waters. The next task is then to use this information for selecting and ranking upgrading projects to improve the situation. CARE-S is a computer based system developed to meet this challenge. It is designed for sewer and storm water network rehabilitation planning. It provides fundamental instruments for estimating the current and future condition of sewer networks, i.e. performance indicators, selecting and ranking of rehabilitation projects and long-term investment needs. The procedure for selection and ranking of projects is supported by tools for analysis of structural failures and hydraulic performance. Socio-economic issues are also included in the priority ranking process of CARE-S
Ricerca policentrica del Gruppo Italiano Dermatiti da Contatto e Ambientali (GIRDCA) sulla sensibilità ad alcol oleilico e ad Amerchol L-101.
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Italian Euromelanoma Day Screening Campaign (2005-2007) and the planning of melanoma screening strategies
No full textAlthough no study has definitively shown that unfocused screening of skin cancer is effective, many campaigns have been organized with the aim of increasing awareness on melanoma risk factors. The objective of this study was to analyse the results of the Skin Cancer Screening Day in Italy during the period 2005-2007, to determine the priorities for melanoma control plans in a Mediterranean country. A total of 5002 patients were screened by dermatologists in 31 cities. Individuals who considered themselves to have many naevi and those with a family history of melanoma showed a higher number of common and atypical naevi. Ten melanomas, 20 basal cell carcinomas and two squamous cell carcinomas were histopathologically confirmed. Our observations provide the following suggestions for melanoma prevention strategies: (a) an unfocused campaign is suitable to inform the public about the importance of self-examination of the skin, but is not useful to identify a larger number of melanomas; and (b) melanoma screening campaigns should focus on a selected population, which meets rigorous risk criteria to maintain higher cost-effectiveness. The financial support to effective melanoma screening programmes could be increased, especially in southern populations where lower levels of self-surveillance and socioeconomic conditions represent risk factors for late identification of melanoma
