Etude de la Matière Organique Dissoute Chromophorique et du rayonnement solaire (UV-visible) dans les eaux de surfaces côtières méditerranéennes et articques

Afin de comprendre, caractériser et prédire l évolution des cycles biogéochimiques océaniques face au changement climatique global, il est nécessaire d appréhender au mieux la dynamique de la matière organique (MO) au niveau des interfaces terre/océan . Dans ce contexte, l objectif général de cette thèse était d améliorer les connaissances sur la dynamique de la fraction dissoute chromophorique de la MO (CDOM) des eaux de surface côtières méditerranéennes et arctiques, et d en déterminer l impact sur l atténuation du rayonnement UV (UVR) et visible (PAR) sous-marin. Pour cela, l étude des propriétés optiques d absorbance et de fluorescence de la CDOM, couplée à des mesures radiométriques atmosphériques et sous-marines, ont été réalisées lors d un cycle saisonnier en Baie de Marseille (station SOFCOM), et lors d une mission océanographique en Mer de Beaufort durant l été 2009. La Baie de Marseille est caractérisée par des quantités de CDOM faibles (aCDOM(350) = 0,10 +- 0,02 m-1), particulièrement à la fin de la période estivale de stratification, à cause de l intensité de l éclairement solaire, enrichi en UVR-B, qui dégrade et blanchie cette CDOM (SCDOM = 0,023 +- 0,003 nm-1). Dans cette zone côtière fortement urbanisée, la dynamique de la CDOM est pilotée par des processus biotiques (production biologique in situ et induite par les intrusions épisodiques du panache du Rhône) et abiotiques (photo-blanchiment et brassage). La CDOM est essentiellement d origine autochtone, même lors d événements d intrusion du panache du Rhône (photo-dégradation de la CDOM terrestre durant son transit). Lors des périodes d efflorescences algales, la CDOM se compose principalement de matériel récent, de type protéique (pic T), qui absorbe préférentiellement les courts UVR. Ces pulses de CDOM récente se superposent à un persistent signal de fond de CDOM composé majoritairement de matériel âgé, de type humique (pics M et C), qui absorbe les UVR et également le PAR. Au niveau du plateau Canadien de la Mer de Beaufort, la CDOM est très abondante (aCDOMmax(350) = 6,36 m-1), fortement influencée par les apports allochtones du Mackenzie (pics A-C et M) et décroit de manière conservatrice avec la salinité. Dans les eaux marines (salinité >25), la CDOM, qui présente de plus faibles concentrations (aCDOM(350) = 0,21 +- 0,13 m-1), provient d une production biologique in situ récente favorisée par des upwellings ainsi que d injections de CDOM (pics B-T et M) lors de la formation/fonte de la glace de mer. Etonnamment, la source principale du composé humique marin (pic M) n est pas autochtone. Elle est issue d apports allochtones provenant du Mackenzie. Celui-ci draine en effet de nombreux lacs qui sont le siège d une intense activité biologique, et il est proposé dans cette thèse que les macrophytes qui s y développent seraient à l origine du pic M. Cette source de CDOM biologique allochtone, couplée aux processus de photo-blanchiment et d absorption sur les particules de la CDOM terrestre, pourraient expliquer les valeurs élevées de SCDOM (≈ 0,020 nm-1) du Mackenzie en été.To understand, characterize, and predict the evolution of oceanic biogeochemical cycles in relation to the global climate change, it is necessary to better understand the dynamics of organic matter (OM). In this context, the overall objective of this thesis was to get more insights chromophoric dissolved fraction of OM (CDOM) dynamics in surface Mediterranean and Arctic coastal waters and to determine the impact on attenuation of ultraviolet (UVR) and visible (PAR) underwater radiation. For this, the study of optical properties of absorbance and fluorescence of CDOM, coupled with atmospheric and underwater radiometric measurements, were made during a seasonal cycle in the Bay of Marseille (SOFCOM station), and in the Beaufort Sea during summer 2009. The Bay of Marseilles is characterized by low amounts of CDOM (aCDOM(350) = 0.10 +- 0.02 m-1), particularly in end summer stratification period due to the intensity of the solar irradiance, enriched in UVR-B, which degrades and bleaches CDOM (SCDOM = 0.023 +- 0.003 nm-1). In this highly urbanized coastal area, the dynamics of CDOM are driven by biotic processes (in situ biological production and within the Rhône River plume) and abiotic (photo-bleaching and mixing). Our results showed that CDOM is mostly of autochthonous origin, even during Rhône plume intrusion events (photo-degradation of terrestrial CDOM during the transit). During bloom periods, the CDOM consists mainly of a recent type protein (peak T), which preferentially absorbs in the short UVR. These pulses of recent CDOM are superimposed on a persistent background of CDOM mainly composed of aged material, humic-type (peaks M and C), which absorbs UVR and PAR. Over the Canadian shelf of the Beaufort Sea, CDOM is highly abundant (aCDOMmax (350) = 6.36 m-1) and strongly influenced by allochthonous inputs from the Mackenzie (peaks A-C and M) decreasing conservatively with salinity. In marine waters (salinity> 25), CDOM had lower concentrations (aCDOM(350) = 0.21 +- 0.13 m-1) and originated from a recent in situ biological production favored by upwelling and brine injections (peaks B-T and M). Surprisingly, the main source of the marine humic-like component (peak M) was not autochthonous. This material originates from allochthonous inputs from the Mackenzie River, which traverses numerous lakes where intense biological activity occurs. We suggest that this activity is mainly due to the macrophytes development, which may in part explain the origin of the peak M. This source of organic allochthonous CDOM coupled to other processes such as photobleaching and absorption on the particles of terrestrial CDOM, could explain the high values of SCDOM (≈ 0.020 nm-1) recorded in the Mackenzie during summertime.AIX-MARSEILLE2-Bib.electronique (130559901) / SudocSudocFranceF

Honey bee brood ring-test: method for testing pesticide toxicity on honeybee brood in laboratory conditions

contribution to session IV Test methodology The Experimental unit of entomology (INRA, France) developed a new in vitro method to assess effects of pesticides on honey bee larvae. The method consists in rearing bee larvae in plastic cells. The larvae are fed with diet containing 50% of fresh royal jelly and 50% of an aqueous sugar and yeast extract solution, and reared in an incubator at 35 °C and 96% relative humidity. According to that method, 9 tests (7 in 2008 and 2 in 2005) were carried out in 7 laboratories and different countries. The objective of these trials was to assess the LD50 for dimethoate 48 hours after an acute exposure. The LD50 values ranged from 1.5 μg a.i./larva to 8.8 μg a.i./larva, with 2 tests with particularly high values (5.0 and 8.8 μg a.i./larva). In 7 tests, these values ranged from 1.5 μg a.i./larva to 3.1 μg a.i./larva. Such variability may be due to the colony origin, the season and larva heterogeneity at grafting. Solutions are proposed to improve the method through the continuation of the ring test. Keywords: Apis mellifera, brood, in vitro test, dimethoat

The ABC130 barrel module prototyping programme for the ATLAS strip tracker

For the Phase-II Upgrade of the ATLAS Detector, its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100 % silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-25) and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.Comment: 82 pages, 66 figure

Medical Devices Development: the Bottom-up or the Top-down Approach

International audienceBiomedical sensors are often developed under a bottom-up approach, i.e. the researcher point of view or laboratory approach. This is usually the case for microfluidic based integrated systems. The small number of such devices actually translated for use in clinical situations is mostly due to the need of sample pre-treatment by specially trained people and to the fact that industrial transfer had not been taken into account since the very beginning of the development. Conversely, the top-down approach places the end-user at the center of development discussion. In this end-user point of view approach, the participation of industrial, medical and end-users partners more often leads to the design of fully integrated and automated devices which, furthermore, can be manufactured using conventional industrial capabilities. In this opinion communication, we briefly summarize the most common biosensors technologies and we explain how immuno-combined devices may help addressing constraints related to their use in clinical situations in terms of usability by non-trained people, automation and integration

Effects of Dry and Wet Negev Soil–Dust Deposition on the Induction of Autoxidation of Soil–Dust Lipid Components

Lipids and their oxidation products were quantified in loess samples from the Negev Desert (Israel), well known to be a source of desert dusts in the eastern Mediterranean Basin. The results obtained showed the presence of higher plant material (angiosperms and gymnosperms), but also bacteria and fungi. Although a strong autoxidation of lipids could be demonstrated, the resulting oxidation products appeared to be weakly accumulated, likely due to the high temperatures and solar irradiance observed in the Negev Desert. Incubation of this dust analogue in fresh water (to mimic their behavior in rainwater) resulted in the release of metal ions (mainly iron), but also a fast heterolytic degradation of their weak content of hydroperoxides. Induction of autoxidation processes in dry and wet atmospheric dusts arising from the Negev Desert in seawater (needing simultaneous presence of metal ions and hydroperoxides) seems thus very unlikely due to the relatively high pH of seawater hindering metal dissolution and the degradation of hydroperoxides in rainwater

Effects of Dry and Wet Negev Soil–Dust Deposition on the Induction of Autoxidation of Soil–Dust Lipid Components

International audienceLipids and their oxidation products were quantified in loess samples from the Negev Desert (Israel), well known to be a source of desert dusts in the eastern Mediterranean Basin. The results obtained showed the presence of higher plant material (angiosperms and gymnosperms), but also bacteria and fungi. Although a strong autoxidation of lipids could be demonstrated, the resulting oxidation products appeared to be weakly accumulated, likely due to the high temperatures and solar irradiance observed in the Negev Desert. Incubation of this dust analogue in fresh water (to mimic their behavior in rainwater) resulted in the release of metal ions (mainly iron), but also a fast heterolytic degradation of their weak content of hydroperoxides. Induction of autoxidation processes in dry and wet atmospheric dusts arising from the Negev Desert in seawater (needing simultaneous presence of metal ions and hydroperoxides) seems thus very unlikely due to the relatively high pH of seawater hindering metal dissolution and the degradation of hydroperoxides in rainwater

Effects of Dry and Wet Negev Soil–Dust Deposition on the Induction of Autoxidation of Soil–Dust Lipid Components

International audienceLipids and their oxidation products were quantified in loess samples from the Negev Desert (Israel), well known to be a source of desert dusts in the eastern Mediterranean Basin. The results obtained showed the presence of higher plant material (angiosperms and gymnosperms), but also bacteria and fungi. Although a strong autoxidation of lipids could be demonstrated, the resulting oxidation products appeared to be weakly accumulated, likely due to the high temperatures and solar irradiance observed in the Negev Desert. Incubation of this dust analogue in fresh water (to mimic their behavior in rainwater) resulted in the release of metal ions (mainly iron), but also a fast heterolytic degradation of their weak content of hydroperoxides. Induction of autoxidation processes in dry and wet atmospheric dusts arising from the Negev Desert in seawater (needing simultaneous presence of metal ions and hydroperoxides) seems thus very unlikely due to the relatively high pH of seawater hindering metal dissolution and the degradation of hydroperoxides in rainwater

Thiophenium Salts as New Oxidant for Redox Polymerization under Mild- and Low-Toxicity Conditions

In mild conditions (under air, room temperature, no monomer purification and without any energy activation), redox free radical polymerization (RFRP) is considered as one of the most effective methods to polymerize (meth)acrylate monomers. In the past several years, there has been a growing interest in research on the development of new redox initiating systems (RISs), thanks mainly to the evolution of toxicity labeling and the stability issue of the current RIS based on peroxide and aromatic amine. In this study, a new, low-toxicity RIS based on thiophenium salt as the oxidant species is presented with various reductive species. The reactivity and the stability of the proposed RISs are investigated and the synthesis of new thiophenium salts reported

SmarTTransfuser project: toward an automated point-of-care transfusion safety system

BioMed 2013 14-16 November 2013, Bangkok, ThailandBefore each transfusion of red blood cell concentrate, a final ABO compatibility test is carried out at the patient's bedside on a piece of card and interpreted visually. Despite this ultimate test, transfusion accidents still occur due to group incompatibility, which can be lethal. In order to improve this test, we have developed a specific device based on microarrays for the validation of a smart and safe transfuser in the context of critical transfusional situations. This miniaturized device incorporates a biochip to analyze ABO compatibility in order that the hemagglutination reaction of red blood cells with IgMs in solution be replaced by specific capture and concentration of IgMs on microarrays. Results indicate that a specific immunocapture is obtained with globular concentrates and with different total blood. Smarttransfuser is a smart device developed in collaboration with the French Blood Transfusion Center for the optimization at the patient's bedside of an ultimate test prior to transfusion

Functional analysis to drive research and identify regulation requirements: an example with a lithium monitoring device

International audienceMedical device development is often understood as a linear process with design stages occurring sequentially. First stages are usually performed in order to specify the future device definition through interviews/meetings of the end-users, researchers and manufacturers. Because the medical device is original, these first stages mainly involve end-users and researcher. However, regulation constraints and economic reality sometimes makes manufacturers hesitant to base the industrial development on this initial basis. Functional analysis, well known by manufacturers, is a method used to accurately define the final functions of a medical device. In this conference, we estimate that the functional analysis can be put to profit in a more efficient way if researchers and end-users get familiar with it prior to the interview/meeting stages. Although the results of such knowledge democratisation is not demonstrated here, we present the function analysis conducted on a lithium monitoring device according to this multidisciplinary approach. We also show that function analysis can be used not only to drive research actions but also to identify regulation requirements