Approche spatiale des inégalités d'exposition environnementale et socioéconomiques Quelle influence sur les inégalités de cancer ? Projet Cancer inégalités régionales, cantonales et environnement (CIRCE)

National audienceINTRODUCTION. La progression de l'incidence du cancer en France et dans les pays développés suscite une interrogation sur l'origine de cette croissance et notamment sur l'importance de la composante environnementale de cette croissance. Les études de corrélations écologiques utilisant les Systèmes d'information géographique (SIG) peuvent apporter un éclairage nouveau sur la relation entre cancer et facteurs environnementaux et socio-économiques. Les objectifs sont de 1) Proposer une méthodologie utilisant des indicateurs permettant de mettre en évidence les inégalités spatiales d'exposition environnementale, de niveau socio-économique et de mortalité par cancer et 2) Comprendre les relations entre cancer et facteurs environnementaux et socioéconomiques en croisant ces données par une étude de corrélation écologique à l'échelle cantonale. MATERIEL/METHODES. A partir des bases de données descriptives de l'environnement, des indicateurs de l'exposition environnementale sont proposés : un indicateur de pollution de l'air à partir du registre européen d'émission des polluants (European pollutant emission register, EPER) pour une cinquantaine de polluants, un indicateur général de contamination des sols à partir de BASIAS, un indicateur de pollution agricole ou urbaine à partir de Corine Land Cover. A partir du recensement INSEE descriptif de la population, l'indice de défaveur sociale de Townsend peut être construit. A partir des données du Centre d'épidémiologie sur les causes médicales de décès (CépiDc) de l'Inserm, le risque relatif de mortalité par cancer a pu être défini. RESULTATS. La région Nord-Pas-de-Calais a été choisie pour illustrer les résultats. Chacun des indicateurs est cartographié à l'échelle des cantons mettant en évidence des disparités géographiques plus ou moins importantes. La carte de l'indice de Townsend fait ressortir la région Lilloise ainsi que le bassin minier comme les zones les plus défavorisées socialement. La cartographie des indices généraux d'exposition environnementale semble faire ressortir ces mêmes zones. Les indicateurs d'exposition à partir d'EPER mettent en évidence de fortes disparités spatiales de l'exposition, et des différences importantes suivant le polluant considéré. Concernant le cancer, les résultats sont variables selon la localisation cancéreuse analysée ; dans le Nord-Pas-de-Calais, les situations récurrentes de surmortalité sont localisées autour des grands pôles. Certains cantons semblent cumuler les inégalités sociales, environnementales et sanitaires. Le croisement de ces données spatialisées par canton permettra de définir les liens éventuels entre cancer, environnement et niveau socio-économique. DISCUSSION ET CONCLUSION. Bien que cette approche comporte quelques limites comme la non prise en compte de la mobilité à court et long terme des populations ou encore les temps de latence relativement long pour le cancer, l'utilisation des SIG dans le cadre d'études de corrélations écologiques apporte une vision nouvelle des disparités spatiales et permettent de mieux comprendre la complexité du lien environnement, social et sant

Analyser les inégalités spatio-temporelles de cancer pour mieux comprendre le lien cancer environnement Le projet CIRCE (Cancer inégalités régionales cantonales et environnement)

National audienceINTRODUCTION. La progression de l'incidence du cancer en France et dans les pays développés suscite une interrogation sur l'origine de cette croissance et notamment sur l'importance de la composante environnementale de celle-ci. MATERIEL ET METHODES. Les études de corrélation écologique utilisant les Systèmes d'Information Géographique (SIG) peuvent apporter un éclairage nouveau sur la relation entre cancer et environnement en prenant en considération l'information fournie par la spatialisation des données. RESULTATS. Des programmes de cette nature se sont développés pour analyser des excès de cancer, notamment aux Etats-Unis (Cape Cod, Long Island). Le programme CIRCE a été conçu pour développer une approche de ce type en France. Il réunit l'INERIS, l'INSERM U897, 4 ORS (Picardie, Ile-de-France, Nord-Pas-de-Calais, Rhône-Alpes), le registre des cancers de l'Isère et l'UTC. Il comprend deux phases. La phase I se décompose en 3 opérations : 1) production des cartes de données lissées de mortalité sur les 4 régions et de morbidité sur l'Isère 2) transformation des principales bases de données environnementales en base de données spatialisées 3) croisement des données sanitaires et environnementales. La phase II vise à investiguer les zones contrastées (à très fort ou très faible taux). DISCUSSION ET CONCLUSION. Les études de corrélation écologique permettent d'apporter un éclairage nouveau permettant de mieux comprendre la relation entre cancer et environnement en générant notamment de nouvelles hypothèses. Les premiers résultats acquis sur 4 régions montrent que cette démarche est possible en France et peut être étendue à d'autre

Numerical modelling of coupled groundwater flow and heat extraction from subsoil.

The subsoil can be used to store or extract heat for cooling or heating buildings, respectively, via a ground-coupled heat pump (GCHP) and the Ground heat exchanger (GHE) commonly used consist of HPDE pipes. The present contribution deals with the role of groundwater flow in the performance of GHEs installed in vertical boreholes. A mathematical model in 2D space is introduced, comprising a pair of partial differential equations of parabolic and elliptic type for soil temperature and ground water velocity field, respectively. The equations have been solved numerically by mean of Difference Finite method and Finite Element Method. The numerical model has been validated by comparing the results with the solutions of Moving infinite line source (MILS) model. The soil temperatures established in a sand around GHE operating in heat mode are calculated either assuming a uniform velocity field and by taking into account the correct seepage around the GHEs to investigate how much the proper modelling of groundwater flow around the borehole affects the results

FIOH-sponsored newsletter misrepresents asbestos hazards in Zimbabwe

International audienceThe Finnish Institute of Occupational Health (FIOH) has received support from the World Health Organization (WHO) and the International Labor Office (ILO) to publish the African Newsletter on Occupational Health and Safety. The African Newsletter on Occupational Health and Safety should not be a medium for industry propaganda, or the source of misinformation among the workers of Africa. Instead, FIOH should provide the same level of scientific information in Africa that it does in Finland and other developed countries

FIOH-sponsored newsletter misrepresents asbestos hazards in Zimbabwe

International audienceThe Finnish Institute of Occupational Health (FIOH) has received support from the World Health Organization (WHO) and the International Labor Office (ILO) to publish the African Newsletter on Occupational Health and Safety. The African Newsletter on Occupational Health and Safety should not be a medium for industry propaganda, or the source of misinformation among the workers of Africa. Instead, FIOH should provide the same level of scientific information in Africa that it does in Finland and other developed countries

Double crystallization and phase separation in polyethylene—syndiotactic polypropylene di-block copolymers

Crystallization and phase separation in the melt in semicrystalline block copolymers (BCPs) compete in defining the final solid state structure and morphology. In crystalline–crystalline di-block copolymers the sequence of crystallization of the two blocks plays a definitive role. In this work we show that the use of epitaxial crystallization on selected crystalline substrates allows achieving of a control over the crystallization of the blocks by inducing crystal orientations of the different crystalline phases and a final control over the global morphology. A sample of polyethylene-block-syndiotactic polypropylene (PE-b-sPP) block copolymers has been synthesized with a stereoselective living organometallic catalyst and epitaxially crystallized onto crystals of two different crystalline substrates, p-terphenyl (3Ph) and benzoic acid (BA). The epitaxial crystallization on both substrates produces formation of highly ordered morphologies with crystalline lamellae of sPP and PE highly oriented along one direction. However, the epitaxial crystallization onto 3Ph should generate a single orientation of sPP crystalline lamellae highly aligned along one direction and a double orientation of PE lamellae, whereas BA crystals should induce high orientation of only PE crystalline lamellae. Thanks to the use of the two selective substrates, the final morphology reveals the sequence of crystallization events during cooling from the melt and what is the dominant event that drives the final morphology. The observed single orientation of both crystalline PE and sPP phases on both substrates, indeed, indicates that sPP crystallizes first onto 3Ph defining the overall morphology and PE crystallizes after sPP in the confined interlamellar sPP regions. Instead, PE crystallizes first onto BA defining the overall morphology and sPP crystallizes after PE in the confined interlamellar PE regions. This allows for discriminating between the different crystalline phases and defining the final morphology, which depends on which polymer block crystallizes first on the substrate. This work also shows that the use of epitaxial crystallization and the choice of suitable substrate offer a means to produce oriented nanostructures and morphologies of block copolymers depending on the composition and the substrates

Combining Both Acceptorless Dehydrogenation and Borrowing Hydrogen Mechanisms in One System as Described by DFT Calculations

The mechanisms for the formation of N-substituted hydrazones by coupling of alcohols and hydrazine, achieved by the sequential processes of acceptorless dehydrogenation and borrowing hydrogen, has been unveiled by density functional theory (DFT) calculations. The release of water and molecular hydrogen as subproducts, combined with the Mn-PNN pincer based catalyst describe a green environment. Mechanistically, apart from describing a complex system of three coupled catalytic pathways, calculations describe the pivotal role of two intermediates, which participate in two catalytic pathways each one. Finally, predictive catalysis plays the role to push forward this reaction toward milder conditions, and thus in line with green chemistry standards

Crystallization Behavior of Block Copolymers of Isotactic Polypropylene and Linear Low-Density Polyethylene

The crystallization behavior and the overall kinetics of the crystallization from the melt of samples of diblock copolymers (BCPs) composed of semicrystalline blocks of isotactic polypropylene (iPP) and linear low-density polyethylene (LLDPE), synthesized with an isospecific living organometallic catalyst, have been studied. Samples with different lengths of the two crystallizable blocks and different 1-octene concentrations in the LLDPE block have been analyzed. In almost all samples, the iPP block crystallizes first upon cooling from the melt, producing a bundle-like crystal morphology according to the moderate stereoregularity of the iPP dictated by the catalyst, and the LLDPE block crystallizes at a slightly lower temperature without altering the crystal morphology. All samples have been isothermally crystallized from the melt at different temperatures, and the effect of the covalently linked LLDPE block on the crystallization kinetics of iPP has been analyzed. For almost all samples, only the iPP blocks crystallize during the isothermal crystallization at the chosen crystallization temperatures. The LLDPE block remains in the melt and crystallizes after cooling to room temperature. Only in the samples with the lowest octene fraction of 1.1 mol % and shortest iPP block (wiPP = 15 wt %) does the LLDPE block crystallize coincidently with the iPP block in the isothermal step. The analysis of the kinetic data has shown that the covalently linked LLDPE block reduces the overall crystallization rate of the iPP block, with respect to the iPP homopolymer, and the crystallization rate decreases with increasing the length of the LLDPE block. This slowdown of the crystallization rate has been attributed to a dilution exerted by the linked molten LLDPE block. The Avrami indices of all BCPs are between 2 and 3. They are slightly lower than those of the iPP homopolymer, suggesting the occurrence of dimensionality restrictions imposed by confinement into the phase-separated microdomain morphology, confirming the hypothesis of the formation of a phase-separated structure in the melt of these iPP-b-LLDPE, which is partially retained upon crystallization. This work contributes to sheding light on the crystallization mechanism in semicrystalline BCPs, crucial to elucidating and upgrading the performances of these innovative copolymers when employed as compatibilizers in polymer blends

Phase Separation and Crystallization in Monodisperse Block Copolymers of Linear Low-Density Polyethylene and Isotactic Polypropylene

Samples of block copolymers (BCP) constituted by semicrystalline blocks of linear low-density polyethylene (LLDPE) and isotactic polypropylene (iPP) of different block lengths (iPP-b-LLDPE) have been prepared by living polymerization using the hafnium-based catalyst that provides high steric control and isotactic propagation of propene units. The LLDPE blocks are random ethylene/1-octene copolymers with 1-octene concentrations between 1 and 3 mol %. The crystallization behavior and the morphologies in the melt and after the crystallization of iPP-b-LLDPE are presented. The iPP block melts at 135 °C, according to the moderate isotacticty, whereas the LLDPE blocks melt at lower temperatures, between 101 and 113 °C, depending on the 1-octene concentration. Both blocks crystallize from the melt and wide-angle diffraction and small-angle scattering profiles acquired with synchrotron radiation during cooling have demonstrated that the iPP block crystallizes first upon cooling, except for the sample with the lowest iPP molecular mass, for which PE and iPP crystallize almost simultaneously. The small-angle scattering recorded during cooling and crystallization of iPP and LLDPE blocks shows the emergence of a single broad scattering peak ascribed to the formation of stacks of crystalline lamellae of indistinguishable iPP and LLDPE with values of the long period of 13-14 nm. Electron microscopy (TEM) analysis allowed us to image the microphase-separated microdomain structure present in the melt and frozen or preserved at room temperature after crystallization. The TEM analysis has demonstrated that phase-separation of the dissimilar blocks occurs in the melt. The formed microdomain structure is preserved after crystallization of both blocks, and pass-through crystallization occurs with iPP and PE lamellae crossing through the different microdomains without overwhelming the microphase-separated structure