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Introduction Most discussions of the importance and applicability of quality cost relate to manufacturing[1]. The reduction in the cost of non-conformance is a popular motive for quality cost implementation since [...]

L’utilisation du tritium dans les réacteurs CANDU (Canada Deutérium Uranium), dans l’industrie, pour la production de sources et de peintures luminescentes, dans l’exploration pétrolière et gazière, dans les hôpitaux pour des tests diagnostiques, en radiothérapie et en recherche, rend le contrôle de ses rejets particulièrement important au Canada. Ces rejets sont réglementés et étroitement surveillés par la Commission canadienne de sûreté nucléaire (CCSN). Certains groupes d’intérêt et de citoyens prétendent cependant que l’incertitude scientifique sur les effets du tritium sur la santé et l’environnement est telle que la réglementation des installations rejetant ou utilisant du tritium serait inadéquate. Pour répondre à ces inquiétudes, la CCSN a demandé à son personnel d’entreprendre le projet intitulé « Études sur le tritium». Dans le cadre de ce projet, le devenir du tritium dans l’environnement ainsi que ses effets sanitaires, ont été étudiés au moyen de mesures directes sur le terrain ainsi qu’à travers la revue de la littérature scientifique la plus récente sur le sujet. Ce projet a permis de conclure que les mesures de radioprotection concernant le tritium ainsi que les mécanismes utilisés pour le réglementer sont adéquats pour protéger la santé et la sécurité des Canadiens.

The activation of carcinogenic aromatic and heterocyclic amines and benzo[a]pyrene-7,8-diol to intracellular electrophiles by prostaglandin H synthase (COX) is well documentedfor ovine sources of this enzyme. Here, the arachidonic acid-dependent activation of substrates by human (h)COX-1 and-2 is examined, utilizing recombinant enzymes. The COX-dependent activation of benzidine (BZ), 4-aminobiphenyl, (+)benzo[a]pyrene-7,8-diol, (+)benzo[a]pyrene-7,8-diol, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3-methylimidazo [4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP), and 4,4′-methylenebis(2-chloroaniline) (MOCA) is assessed by means of COX-catalyzed, covalent DNA binding. The hCOX isozymes activated all substrates tested, activation varied from barely detectable for IQ (0.76 and 1.52 pmol bound/mg DNA for COX-1 and -2, respectively) to a high of 65 and 117 pmol bound/mg DNA for COX-1 and -2, respectively, for the activation of MOCA. BZ, which is an excellent peroxidase substrate, did not exhibit high DNA binding levels in hCOX assays and this phenomenon was found to be due to high levels of binding to protein, which effectively competed with the DNA for binding in the assay. The demonstrated ability of the COX enzymes to activate a variety of environmental and dietary carcinogens indicates a potential role for COX in the activation pathway of aromatic and heterocyclic amines and polycyclic hydrocarbons at extra-hepatic sites during early or late stages of carcinogenesis.

The occurrence of nonconformance is relatively high in construction and can affect the profit margin and competitiveness of a construction firm. Applies a quality cost matrix developed by one of the authors to a real construction project. Presents findings that indicate the applicability of the matrix, the main problems’ potential for improvement and their frequency of occurrence, and the consequences of implementing the matrix on site management.

The flow of recently photoassimilated carbon into proteins, lipids, and polysaccharides was studied with asynchronous Selenastrum capricornutum populations during exposure to and recovery from 30 and 100 µg Cd-liter−1. During a 48-hr exposure to Cd. increases in Cd cell quotas were accompanied by nearly exponential decreases in growth and photosynthesis and by a disruption of the pattern of carbon allocation to macromolecules. In particular, relative to the control, the cells exposed to Cd allocated a higher percentage of carbon to the synthesis of polysaccharides. After the addition of EDTA (recovery period), Cd cell quotas decreased and growth recovery was accompanied by the recovery of photosynthesis and by an enhanced flow of carbon to lipids and proteins. The results of the experiment suggest that the measurement of the distribution of recently photoassimilated carbon into macromolecules has potential for monitoring the effects of toxic effluent discharges on primary producers.Copyright 1993, 1999 Academic Press