LES NANOPARTICULES: QUELS RISQUES EN SEINE ?

32 pInternational audienceL'obtention de nanoparticules (NPs) manufacturées et les propriétés physico-chimiques spécifiques qu'elles présentent autorisent aujourd'hui des applications de plus en plus nombreuses et innovantes. La quantité de nanoparticules manufacturées mises sur le marché est en constante augmentation et elles sont aujourd'hui présentes dans de nombreux produits de consommation courante. Cela alimente un débat croissant sur les coûts environnementaux et sociétaux qui pourraient dépasser les bénéfices escomptés par l'utilisation des nanotechnologies en général et des nanomatériaux ou nanoparticules (i.e. taille < 100 nm) en particulier. Elles sont devenues un enjeu majeur de santé publique du point de vue de la toxicité potentielle qu'elles pourraient engendrer dans les écosystèmes. Les nanoparticules peuvent en effet présenter un risque écotoxicologique (dispersion et dégradation dans l'environnement) et un risque en termes de santé humaine (exposition au poste de travail par exemple). Il est donc nécessaire d'évaluer la persistance, le devenir et l'impact de ces nouveaux polluants sur les écosystèmes et sur la qualité des ressources naturelles (eaux, cultures, etc...). Dans ce contexte, l'objectif de cette étude était de mieux cerner l'état physique et chimique des NPs dans des concentrations représentatives des niveaux de toxicité observés et dans des conditions proches de celles des milieux naturels. Elle s'est focalisée sur l'eau de Seine, représentative des eaux naturelles de surface qui sont un des vecteurs principaux de la dispersion de ces NPs manufacturées. Les NPs étudiées ici sont produites en grande quantité et largement utilisées dans différents domaines industriels : il s'agit de NPs d'oxydes de zinc (ZnO) et de dioxyde de titane (TiO2). L'analyse des NPs de ZnO par XPS a mis en évidence l'existence d'un cœur de ZnO et d'un coquille de Zn(OH)2 en surface. Parallèlement, des NPs enrobées ont été étudiées et caractérisées, afin de mettre en évidence le rôle de l'enrobage organique sur la solubilité des NPs. Les expériences de mesures de solubilité des nanoparticules manufacturées en milieu naturel ont été réalisées par utilisation combinée des techniques de DMT et d'UF, associée à des calculs thermodynamiques. Il s'avère que la forme nanoparticulaire du TiO2 n'est pas davantage soluble que ses homologues microparticulaire ou macroparticulaire. A l'inverse, une fraction non négligeable des nanoparticules d'oxydes de zinc est rapidement dissoute dans l'eau de Seine. Puis les NPs sont "piégées" dans des phases secondaires carbonatées, ce qui peut signifier leur isolement par rapport au milieu et donc l'arrêt des réactions impliquant les NPs, soit une forme de passivation des nanoparticules. Le comportement des NPs dans le milieu est donc en grande partie contrôlé par la couche directement à leur surface (Gélabert et al., 2014; Sivry et al., 2014) : la couche d'hydroxydes de zinc contrôle le Ks apparent, l'enrobage organique augmente la vitesse et le taux de dissolution des NPs et, enfin, la formation d'une gangue carbonatée emprisonne les NPs et provoque potentiellement leur passivation

Opiate withdrawal syndrome in buprenorphine abusers admitted to a rehabilitation center in Tunisia.

Background: Illicit use of high dosage buprenorphine has been well documented in several countries, including Tunisia. Objectives: The aim of this survey is to assess the buprenorphine withdrawal syndrome time course, and how it may be affected by the population characteristics among subjects admitted to a rehabilitation center in Tunisia. Methods: A prospective research has permitted study of the socio-demographic characteristics and assessment of buprenorphine withdrawal syndrome among 32 subjects admitted for buprenorphine dependence by using the clinical opiate withdrawal scale. An ANOVA was conducted to examine the effect of different factors on the withdrawal scores. Results: 32 subjects were included. Among them 30 were males, 27 had been injecting buprenorphine, 16 were poly-drug abusers and 2 had a history of mental disorders. Buprenorphine withdrawal syndrome was of a mild intensity and had a delayed onset. Withdrawal mean scores varied between 0 and 9, and maximum values were reached at day 21. These scores varied significantly over time (p&lt;0,001). The sex v time interaction and the mode of consumption of buprenorphine had significant effects on the withdrawal scores (p&lt;0,001). The poly-drug consumption and the history of mental disorders did not have any significant effect on the withdrawal scores. Conclusion: This study has permitted description of buprenorphine withdrawal syndrome among patients going through a detoxification treatment at a rehabilitation center. Understanding this syndrome would help elaborate effective and suitable buprenorphine dependence management plans

Hypertrophy of the feet and ankles presenting in primary hypertrophic osteoarthropathy or pachydermoperiostosis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Pachydermoperiostosis or primary hypertrophic osteoathropathy is a rare genetic disease with autosomal transmission. This disorder, which affects both bones and skin, is characterized by the association of dermatologic changes (pachydermia or thickening of the skin) and rheumatologic manifestations (periostosis and finger clubbing). Here, we report a new observation of pachydermoperiostosis.</p> <p>Case presentation</p> <p>A 20-year-old North African Tunisian Caucasian man presented with hypertrophic osteoarthropathy. On a clinical examination, we found morphologic abnormalities of his face and extremities associated with skin changes. The laboratory findings were normal. A work-up disclosed no organic etiology. The final diagnosis consisted of pachydermoperiostosis syndrome.</p> <p>Conclusion</p> <p>Pachydermoperiostosis is a rare entity that should be differentiated from secondary hypertrophic osteoarthropathy and chronic rheumatic diseases.</p

Health promoting potential of herbal teas and tinctures from Artemisia campestris subsp maritima: from traditional remedies to prospective products

This work explored the biotechnological potential of the medicinal halophyte Artemisia campestris subsp. maritima (dune wormwood) as a source of health promoting commodities. For that purpose, infusions, decoctions and tinctures were prepared from roots and aerial-organs and evaluated for in vitro antioxidant, anti-diabetic and tyrosinase-inhibitory potential, and also for polyphenolic and mineral contents and toxicity. The dune wormwood extracts had high polyphenolic content and several phenolics were identified by ultra-high performance liquid chromatography-photodiode array-mass-spectrometry (UHPLC-PDA-MS). The main compounds were quinic, chlorogenic and caffeic acids, coumarin sulfates and dicaffeoylquinic acids; several of the identified phytoconstituents are here firstly reported in this A. campestris subspecies. Results obtained with this plant's extracts point to nutritional applications as mineral supplementary source, safe for human consumption, as suggested by the moderate to low toxicity of the extracts towards mammalian cell lines. The dune wormwood extracts had in general high antioxidant activity and also the capacity to inhibit a-glucosidase and tyrosinase. In summary, dune wormwood extracts are a significant source of polyphenolic and mineral constituents, antioxidants and a-glucosidase and tyrosinase inhibitors, and thus, relevant for different commercial segments like the pharmaceutical, cosmetic and/or food industries.FCT - Foundation for Science and Technology [CCMAR/Multi/04326/2013]; Portuguese National Budget; FCT [IF/00049/2012, SFRH/BD/94407/2013]; Research Foundation - Flanders (FWO) [12M8315N]info:eu-repo/semantics/publishedVersio

Comparative characterization of the spawning environments of European anchovy, Engraulis encrasicolus, and round sardinella, Sardinella aurita (Actinopterygii: Clupeiformes) in the eastern coast of Tunisia

Background. The distribution of early ontogenic stages of small pelagic fishes is important for understanding the dynamics of their fluctuating populations. To fill a gap in the knowledge we conducted a comparative analysis on the distribution of eggs and larvae of the exploited populations of European anchovy, Engraulis encrasicolus (L.) and round sardinella, Sardinella aurita (Valanciennes, 1847), in the eastern coast of Tunisia. Materials and methods. A multidisciplinary survey was carried out in the summer of 2008, from June 23 through July 9. Samples were taken over a grid of 71 stations. Temperature and salinity profiles were recorded at each station by CTD casts and water samples were taken by means of a Rosette equipped with Niskin bottles. Ichthyoplankton was sampled by oblique tows with a Bongo net of 60 cm mouth diameter and 335-µm mesh nets. To specify the preferred spawning environment the quotient values were estimated for each variable. Results. The eggs and larvae of both species represented an important proportion of the ichthyoplankton, around 50% for each ontogenic stage. Anchovy mainly spawned in the shelf edge, north-east of Kuriate Island, with a minor spawning area near Cap Bon and Kelibia. The main spawning area of the round sardinella was in the warmer waters. It was located near the major spawning ground of anchovy. Anchovy eggs were scarce in the coastal zones and in the south of the study area, whereas round sardinella eggs were scarce in the north. The main spawning grounds of anchovy coincided with the area of higher zooplankton abundance while round sardinella spawning grounds correspond with those areas of highest chlorophyll-a and zooplankton. This distribution suggests a propensity for food availability, for both adults and larvae, as the location of spawning grounds of these species. Conclusion. Both anchovy and sardinella spawned mainly in deeper waters within the limits of the continental shelf. Each species appeared to have a specific strategy for spawning that was influenced by physical and biological variables

Two-dimensional copper (II) halide-based hybrid perovskite templated by 2-chloroethylammonium Crystal structures, phase transitions, optical and electrical properties

International audienceHybrid inorganic-organic perovskites attracted increasing attention because of variety of their applications in the fields of photovoltaics, photoelectronics and switchable dielectric devices. Diverse molecular functional materials can be assembled by modifying the length of the organic components and inorganic framework dimensionality and, thus, they might be promising candidates to obtain phase-transition materials. In this study, we present a new hybrid perovskite-like compound, (ClC2H4NH3)2CuBr4 (I), which follows the two-dimensional inorganic frameworks of the corner-sharing CuBr6 octahedra. Strikingly, compound (I) displays a dielectric phase transition at around 275 ​K, changing from the non-centrosymmetric space group of Pc (LT phase) to centrosymmetric P21/a (HT phase) upon heating. The crystal structure analyses reveal that the unusual thermally activated conformation change of the 2-chloroethylammonium cations and distortions of CuBr6 4− network in the inorganic layers afford the driving force to the phase transition. Moreover, the Jahn−Teller distortion introduces elongation of coordination bonds in the inorganic planes, which confers higher flexibility to the structure. Compound (I) displays phase transitions at T1 ​= ​270 ​K and T2 ​= ​323 ​K, confirmed by DSC measurements. In addition, the UV/Vis optical spectrum indicates that (I) has an indirect band gap of 1.47 ​eV. This finding may extend the application of 2D layered lead-free hybrid perovskite-type materials to the field of photovoltaic as the photo absorber layer of solar cells

Increase of canine leishmaniasis in a previously low-endemicity area in Tunisia

An epidemiological study of canine leishmaniasis (CanL) was carried out in nine districts of Sfax, in the southern central part of Tunisia. Sera from 250 dogs were tested by two serological methods: the indirect immunofluorescence antibody test and the counter-immunoelectrophoresis. Seven to eight months later, before the next season of transmission, seropositive dogs from the first test were re-examined and a second sampling was performed. Infection status was assessed by serology and by other methods. PCR, in vitro culture and direct examination were applied on blood and other samples (bone marrow, liver, lymph node, spleen and cutaneous biopsies). The seroprevalence of the infection in dogs was 6 %. Infection was then confirmed by at least one other method. The PCR is the method which agreed most with serology, all seropositive dogs were found PCR-positive. The sensitivity of the direct examination and the culture was only 33 % and 55 % respectively as compared with serology. A similar value of seroprevalence has been observed previously in Sousse, in the northern central part of Tunisia. The present report suggests a significant increase of CanL in the Sfax area and confirms that the disease is continuing to move southwards in Tunisia

Increase of canine leishmaniasis in a previously low-endemicity area in Tunisia

An epidemiological study of canine leishmaniasis (CanL) was carried out in nine districts of Sfax, in the southern central part of Tunisia. Sera from 250 dogs were tested by two serological methods: the indirect immunofluorescence antibody test and the counter-immunoelectrophoresis. Seven to eight months later, before the next season of transmission, seropositive dogs from the first test were re-examined and a second sampling was performed. Infection status was assessed by serology and by other methods. PCR, in vitro culture and direct examination were applied on blood and other samples (bone marrow, liver, lymph node, spleen and cutaneous biopsies). The seroprevalence of the infection in dogs was 6 %. Infection was then confirmed by at least one other method. The PCR is the method which agreed most with serology, all seropositive dogs were found PCR-positive. The sensitivity of the direct examination and the culture was only 33 % and 55 % respectively as compared with serology. A similar value of seroprevalence has been observed previously in Sousse, in the northern central part of Tunisia. The present report suggests a significant increase of CanL in the Sfax area and confirms that the disease is continuing to move southwards in Tunisia