70 research outputs found
Novel perfluoropolyethers containing 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole blocks: synthesis and characterization
No full textPeroxidic perfluoropolyethers (PFPEs) are industrial intermediates used by Solvay Solexis for the preparation of different classes of (per)fluoropolyethers (Fomblin®, Galden®, Solvera®, Fluorolink®). The chemistry of these peroxidic compounds has been recently exploited for the synthesis of novel PFPE block copolymers. In the present work we report the synthesis, the structural and physical-chemical characterization of block copolymers obtained by the reaction of peroxidic PFPEs with 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole, a cyclic homopolymerizable perfluoroolefin. These block copolymers combine the most attractive properties of the PFPEs, like the excellent lubrication, the high thermal stability and the optical transparency, with new specific properties which are related to the perfluorodioxolenic block
Utilizzo di stime retrospetttive di esposizione ad asbesto nella valutazione del diritto ai benefici previsti dalla legge 271/93
No full textUtilizzo di stime retrospettive di esposizione ad asbesto nella valutazione del diritto ai benefici della legge 271/93
No full textGlucose-6-phosphate dehydrogenase deficiency and cancer in a Sardinian male population: a case-control study
No full textA case-control study was conducted to test the hypothesis whether the genetic condition of glucose-6-phosphate dehydrogenase (G6PD) deficiency is associated with a reduced risk of cancer. One hundred and eighty seven male cancer patients admitted to hospitals in Cagliari (Sardinia, Italy), between November 1984 and March 1986, were compared with 186 male patients with other diseases, except hemolytic anemia, admitted to the same hospitals in the same period. In contrast to previous reports, our study found no reduction of cancer risk in G6PD-deficient subjects. The study had sufficient statistical power to detect a 0.5-fold decrease in the risk of cancer. The recent suggestion from other studies that tumoral cells of G6PD-deficient subjects can produce their own G6PD, seems to be consistent with this negative finding. Among those subjects presenting some level of erythrocyte G6PD activity, the average enzyme activity was significantly higher in cancer patients than in controls. This finding is consistent with previous experimental studies suggesting a positive correlation between cell proliferation and G6PD activity
Poly(tetrafluoroethyleneperoxides) as useful intermediates for the preparation of novelfluorinated matherial
No full text
Biological monitoring of low-level exposure to benzene
No full textIntroduction: Conflicting opinions exist about the reliability of biomarkers of low-level exposure to benzene. We compared the ability of the urinary excretion of trans, trans-muconic acid (t,t-MA), s-phenilmercapturic acid (s-PMA) and urinary benzene (U-Benz) to detect low level occupational and environmental exposure to benzene. Methods: We monitored airborne benzene by personal air sampling, and U-Benz, s-PMA, t, t-MA and cotinine (U-Cotinine) in spot urine samples, collected at 8 am and 8 pm, in 32 oil refinery workers and 65 subjects, randomly selected among the general population of urban and suburban Cagliari, Italy. Information on personal characteristics, diet and events during the sampling day was acquired through in person interviews. Results: The median concentration of airborne benzene was 25.2 mu g/m(3) in oil refinery workers, and 8.5 mu g/m(3) in the general population subgroup. U-Benz in morning and evening samples was significantly more elevated among oil refinery workers than the general population subgroup (p=0.012, and p=7.4x10(-7), respectively) and among current smokers compared to non-smokers (p=5.2x10(-8), and p=5.2x10(-5) respectively). Benzene biomarkers and their readings in the two sampling phases were well correlated to each other. The Spearman's correlation coefficient with airborne benzene was significant for U-Benz in the evening sample, while no correlation was seen with t, t-MA and s-PMA readings in either samplings. The two benzene metabolites were frequently below limit of detection (LOD), particularly among the general population study subjects (17-9% and 39%, for t, t-MA and s-PMA respectively). Morning U-Cotinine excretion showed a good correlation with U-Benz in the morning and in the evening sampling (p<0.001), and with s-PMA in the evening sample (p<0.001), but not with t, t-MA in either samplings. t, t-MA in the evening sample was the only biomarker showing a moderate inverse correlation with BMI (p<0.05). The multiple regression analysis adjusting by BMI and number of cigarettes smoked during the day confirmed the results of the univariate analysis. Discussion: Our results suggest that unmetabolized U-Benz would allow a more reliable biomonitoring of low-level exposure to benzene than s-PMA and t,t-MA
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