ORPAILLAGE ET CONSTRUCTION DE BARRAGES EN GUYANE FRANÇAISE, UNE ALCHIMIE RISQUEE

10 p.International audienceLe 28 février 2005, la Charte de l'Environnement est adoptée par le Parlement français et promulguée le 1er mars 2005 par le Président de la République. L'article premier stipule que " chacun a le droit de vivre dans un environnement équilibré et respectueux de la santé ". Or, ces dernières années ont vu les services de l'Etat (DIREN, InVS, ONF, etc.) et certains acteurs politiques prendre conscience du désordre régnant dans les méthodes d'exploitation de l'or en Guyane Française et des conséquences de l'exposition au mercure (Hg) pour la santé et l'environnement. Il était temps! Sur l'ensemble de la Guyane on compte 2 compagnies internationales, 26 PME, 60 artisans et 600 à 800 chantiers illégaux d'orpaillage. On (sous)estime ainsi que l'orpaillage illégal emploie près de 10 000 personnes souvent dans des conditions sanitaires déplorables et participe chaque année au rejet direct de 5 à 10 tonnes de mercure dans l'environnement. Alors que les stocks sont estimés à 120 tonnes d'or primaire, les orpailleurs professionnels guyanais admettent un rapport de 1,3 grammes de mercure additionné pour 1 gramme d'or produit. Cependant, les importations de mercure et la production déclarée d'or ne correspondent guère (respectivement 8,4 et 3,2 tonnes en 2003)! Ce mercure d'origine anthropique, d'une part a réalisé des stocks historiques énormes (300 tonnes selon le BRGM) et d'autre part se partage le terrain avec un mercure naturellement important (10 fois plus concentré qu'en Europe), partiellement libéré par l'activité d'extraction minière. C'est pourquoi, l'abandon du mercure légal dont l'interdiction est survenue en 2006, ne règle ni la question de l'orpaillage illégal ni celle de la remobilisation du mercure naturel. C'est dans ce contexte préoccupant qu'a été initiée en 2003 la phase II du programme " Mercure en Guyane ". L'axe II de la phase II du programme (incluant notre projet de recherche) a pour vocation d'étudier le cycle biogéochimique du mercure depuis les sources d'émission jusqu'aux voies de transfert vers les populations humaines. Il a pour cadre géographique le continuum formé par la retenue de Petit-Saut et l'Estuaire du Sinnamary. Le travail effectué s'est attaché à analyser l'impact de la retenue sur le cycle du mercure dans les compartiments sols, eau et atmosphère du continuum. Il a permis d'identifier, de décrire et de quantifier les sites privilégiés de transformation, les cinétiques des processus et les flux de mercure aux interfaces

Matching-Adjusted Indirect Comparisons Applied for Comparative Efficacy of Haematologic Cancer Drugs within Health Economic Analysis

BackgroundDespite clarity in the matching-adjusted indirect comparison (MAIC) methodological guidelines, more research was needed to better understand MAIC applicability in practice, its impact on health economic models, and the outlook of reimbursement agencies on submissions including MAICs. ObjectiveThe aim of the current thesis was to evaluate how MAICs are used in practice to assess the comparative efficacy of haematologic cancer drugs for health economic modelling purposes. Methods Literature review studies were used to assess the underlying evidence of current treatment options for several haematologic cancer indications. MAICs were employed to indirectly compare the efficacy and safety of such treatments while accounting for the specificity of the underlying data. The MAIC findings were incorporated into a cost-effectiveness model and extrapolated over a lifetime span. Different extrapolation models were tested and compared to assess the best fit to the underlying survival curves.ResultsLiterature shows that haematologic cancer treatments are mainly assessed in single-arm trials with few- to no head-to-head comparisons. While MAICs could close these evidence gaps, a lack of methodological uniformity in the way they are conducted in practice and their results reported could lead to biased or frail outcomes further being incorporated into health economic models. Extrapolation of such outcomes with suboptimal parametric curves could add to the compounding uncertainty and result into weak health technology assessment submissions. ConclusionThe current doctoral thesis is advocating for more standardized methodology and reporting standards through a timely reconciliation of the theoretical guidelines with the practical realities

Arany nanorészecskéket tartalmazó bioaktív üveg – biopolimér kompozítok előállítása, jellemzése és alkalmazhatósága: Synthesis, characterization and applicability of bioactive glass – biopolymer composites with gold nanoparticles

Considering that the median age of our population is increasing, bone disorders or skin regeneration problems are of significant concern. The bioactive glass-biopolymer composites are materials with real potential to be used in tissue engineering. It is well-known, that the bioactive glasses (BG) can lead the promotion of growth of granulation tissue. The gold nanoparticles (AuNPs; ~20 nm) can induced the acceleration of wound healing including tissue regeneration, connective tissue regeneration and angiogenesis. It was demonstrated that the AuNPs in the sol-gel derived glass structure retain their properties. Alginate-pullulan (Alg-Pll) composites have good bioactivity and in vivo qualities in terms of bone regeneration. The goal of this study was to obtain the functional composites for future tissue engineering applications using BG with AuNPs introduced in Alg-Pll composites. After structural and morphological characterization of the composites, in vitro and in vivo bioactivity and biocompatibility were evaluated. The obtained results suggest that the obtained composites are materials for future soft tissue and bone engineering applications.  Kivonat A várható élettartam növekedésével egyre növekszik azon betegek száma, amelyek ortopédiai vagy bőr rekonstrukcióra szorulnak. A bioaktív üveg-biopolimer kompozitok potenciálisan alkalmazható anyagok a szövettani sebészetben. Ismert dolog, hogy a bioaktív üvegek (BG) elősegítik a granulációs szövetek növekedését. Az arany nanorészecskék (AuNPs; ~20 nm) gyorsítják a sebgyógyulást beleértve angiogenézist, a szövetek és kötőszövet regenerálódását. Tudjuk, hogy a szól-gél módszerrel előállított üveg szerkezetben bevitt AuNPs képes megőrizni ezen tulajdonságait. Az alginát-pullulán (kompozitok) remek bioaktivitásuknak köszönhetően aktívan részt vesznek az in vivo csont regenerálódásban. A tanulmány célja, hogy olyan funkcionális kompozitokat hozzunk létre, amelyek alkalmazhatók a szövettani sebészetben. Ehhez az Alg-Pll kompozitokban AuNPs tartalmazó BG vittünk be, majd szerkezeti és morfológiai jellemzéseket végeztünk. Ezt követtően az in vitro és in vivo bioaktivitás, valamint biokompatibilitást vizsgáltuk. A kapott eredmények azt sugallják, hogy az előállított kompozitok megfelelnek a lágyrész- és csonttechnikai alkalmazás elvárásainak

Spatio-Temporal Evolution of Sediments Pollution with Mobile Heavy Metals in an Abandoned Mining Area from Romania

The present chapter focuses on spatio-temporal evolution of sediments pollution with mobile heavy metals in five sampling campaigns, in an abandoned gold-bearing mining area from Certeju de Jos, Hunedoara County. The investigated zone is situated in a region where for a long period intense activities of mining exploitation was conducted. For determination of total metals content, sediment samples were dissolved with ultrapure nitric acid to microwave digestion. For the determination of mobile metals concentrations, it used the first step of BCR 701 sequential extraction scheme in a modified form, by reducing the extraction time from 16 hours to 20 minutes by sonication. The total and mobile concentrations of metals were determined by using ICP-MS. The concentrations of the mobile fractions of Cd, As and Cu are between 60 and 98% for Cd, 10 and 38% for As and up to 44% for Cu, indicating their presence in a bioavailable form. Due to the high mobility, these metals can pass from sediment to surface water and, implicitly, to the aquatic ecosystems. The pollution indices, calculated for the total content of As, Cd, Cu, Ni and Pb, indicate the presence of a strong environmental risk of sediment degradation in most investigated site

Validity of the Kinect and Myo armband in a serious game for assessing upper limb movement

A cost-effective, easily-accessible neuro-motor rehabilitation solution is proposed that can determine the range of motion and the kinematic ability of participants. A serious game comprising four-scenarios are developed in which the players control an avatar that mirrors the rotations of the upper-limb joints through multi-channel-input devices (Kinect, Myo, FootPedal). Administered functional reach tests (FRT) challenge the player to interact with a 3D-environment while standing or sitting and using the FootPedal which simulates the action of walking whilst body movement is measured concurrently. The FRT’s complexity level is adapted using a Monte Carlo Tree Search algorithm which determines a virtual object’s position based on the proved ability of the user. Twenty-three volunteers were recruited to play the game in 45-minute sessions. The data show that the system has a more positive impact on players performance and is more motivating than formal therapy. The visual representation of the trajectory of the objects is shown to increase the perception of the participants voluntary/involuntary upper extremity movement, and the results show a comparable inter-session reliability (acceptable-good) over two repeated sessions. A high Pearson correlation demonstrates the validity of using Kinect and Myo devices in assessing upper-limb rehabilitation, and the timing and the clinically relevant movement data have a higher accuracy when the devices are paired