L'inhibition de l'entartrage par les eaux géothermales du sud tunisien. Étude sur site

Une nappe d'eaux fossiles à grande profondeur (800 à 2 700 mètres) a été mise en exploitation dans le Sud-Tunisien pour alimenter une usine d'osmose inverse située à Gabès ayant une production de 15 000 m3 /jour, afin de lutter contre la désertification par irrigation et d'assurer le chauffage de serres pour la production de primeurs. La grande dureté (TH de l'ordre de 100 à 140 °F) de ces eaux géothermales a pour conséquence le colmatage rapide des conduites de distribution : 40 à 50 tonnes de tartre par forage, constitué essentiellement de carbonate de calcium, précipitent chaque année. Ce tartre est constitué d'aragonite comme le montrent la microscopie électronique à balayage et la diffraction des rayons X. Une technique électrochimique, la chronoélectrogravimétrie, permet d'étudier l'inhibition de l'entartrage par des composés de la famille des phosphates inorganiques, des phosphonates organiques et des polycarboxylates. La concentration efficace de chacun de ces inhibiteurs agissant par effet de seuil a été déterminée : elle est de l'ordre de 1,1 à 1,5 mg.l-1 pour l'eau du forage de EL HAMMA. Un essai sur le site de EL MANSOURA a été effectué en privilégiant un inhibiteur produit industriellement dans le Sud-Tunisien, le triphosphate de sodium. A la concentration de 1 mg.l-1 il évite l'entartrage du système de refroidissement de type cascade - piscines et des conduites de distribution.Deep fossil waters are used in Southern Tunisia (Gabès, Kébili, Tozeur) for the Gabès reverse osmosis plant, which delivers a flow rate of 15 000 m3 /day for irrigation and for heating greenhouses used for the production of early fruits and vegetables. Drilling depths vary between 800 and 2 700 meters. Water emerges under a pressure of ca. 20 bars and has a temperature between 50 and 73 °C. Mean flow rate is 7 800 m3 /day.Intake water at the Gabès plant has a salinity of 3.3 g.l-1 ; after reverse osmosis the salinity is less than 0.1 g.l-1. Water used for irrigation has to be cooled. Geothermal waters are characterized by high concentrations of calcium, magnesium, sulphate and chloride. Bicarbonate anions are present at limited concentrations (approx. 2.10-3 mol.l-1) that are, however, sufficient for the formation of large quantities of scale - 40 to 50 tons per year for each drilling. At the outlet of the drill hole, pressure decreases strongly, liberating carbon dioxide to the atmosphere. Water pH increases and the following equilibrium is displaced to the right, with scale precipitation : Ca2+ + 2HCO3-CO2 (g) + CaCO3(s) + H2OScale precipitation has two consequences :- the plugging of distribution pipes: a 85% reduction of the pipe has been observed, after four years, for an initial diameter of 15 cm; - water cooling installations such as cooling towers or pool systems are blocked by large quantities of scale, which have to be removed regularly. Scales have been analysed through inductively coupled plasma spectroscopy and thermogravimetry: calcium carbonate may represent, depending on the origin of the drilling water, 60 to 95% by weight of the solid. Iron oxides, silica, calcium phosphate and aluminum are present. Scanning electron microscopy and X-ray diffraction show that calcium carbonate precipitates in the form of aragonite. This is due to two reasons: the temperature at the drilling outlet is greater than 60 °C and the high magnesium concentration favours aragonite formation. Scale inhibition is possible through the use of certain chemicals such as phosphates, organic phosphonates and polycarboxylates.Chronoelectrogravimetry was used as the experimental method to determine the inhibitor concentration able to suppress scale precipitation. Dissolved oxygen is electrochemically reduced on a gold electrode; hydroxide anions are produced in the vicinity of the electrode and calcium carbonate precipitates according to:4Ca2+ + 4HCO3- + O2 + 4e -> 4CaCO3(s) + 2H2OThe gold electrode is deposited on the quartz disk of a recording microbalance. The electrode is polarized at - 1 V/SCE with a three-electrode potentiostatic device and the weight of CaCO3 deposited is recorded versus time.Four inhibitors have been studied :- PERMATREAT 191, which is the sodium salt of aminotris(methylenephosphonic) acid N(CH2COONa)3; - a proprietary organic phosphonate with high resistance to chlorine oxidation (DEQUEST 6004) ; - phosphonobutanetricarboxylic acid (DEQUEST 7000, BAYHIBIT-AM) ; - a copolymer of acrylic acid and acrylamidopropanesulfonic acid (FERROPHOS 5248). Breakthrough effects are obtained in the case of EL HAMMA water for the following concentrations: PERMATREAT 191: 1.1 mg.l-1 ; DEQUEST 6004: 1.5 mg.l-1 ; DEQUEST 7000: 1.3 mg.l-1 ; FERROPHOS 5248: 1.4 mg.l-1. These concentrations are low and, as a consequence, these inhibitors can be used for antiscale action even with high water flow rates.A field experiment was carried out on the EL MANSOURA drilling where water is cooled in three pools (input water: 5 184 m3 /day, temperature: 60 °C). For economical reasons the chosen inhibitor was sodium triphosphate Na5 P3 O10, which is produced industrially in Southern Tunisia. By chronoelectrogravimetry it has been shown that, with EL MANSOURA water, a breakthrough effect is obtained with a sodium triphosphate concentration of 0.75 mg.l-1.A dosing pump was used to inject sodium triphosphate in such a way that the inhibitor concentration would be 1 mg.l-1 in one of three pools, the two others not being treated. After four months a scale deposit of 23 cm was obtained in the untreated pools and the pipe diameter was reduced by 39%. In the treated pool scale deposit was not observed and the pipe diameter remained unchanged. In the untreated basins, examination of scale with electron scanning microscopy revealed that it was aragonite; in the treated basin, the precipitate was amorphous and an X-ray diffraction pattern with no characteristic bands was obtained.Some algal development was observed in the pool due to phosphate addition but this development was not a nuisance after the four month period. However, it could be suppressed by the use of an organic phosphonate or polycarboxylate as scale inhibitor

Les stenoses tracheales acquises: Experiencede l’hopitalhabibthameur

Introduction: Acquired tracheal stenoses represent rare but serious disease. They are often secondary to inappropriate management of patients under artificial ventilation. The goal of this study is to evaluate our results in the management of these stenoses and to assess the benefits and the limits different therapeutic means.Materials and methods : We carry a retrospective study about 18 cases of acquired tracheal stenoses treated and followed in our department between 1999 and 2006. Initial endoscopic and radiological explorations have been performed in all cases. Treatment of the stenoses was medical, endoscopic and/or surgical. Follow-up was clinical and endoscopicwith a mean period of 22 months.Results : All patients were victims of pathology needing intubation. Tracheotomy was performed after intubation in 50% of cases after a mean period of 12 days (5-20 days). Dyspnea and dysphonia were the major functional symptoms. Initial endoscopy showed a double tracheal stenosis in one case. Stenoses were initialy fibrous in 72.2% of cases and evolutivein 27.8% of cases. CT scan performed in 12 cases and MRI in 2 others allowed to better study stenosis characteristics. RFE was performed in 6 cases and showed an obstructive syndrome in all of them. All patients received medical treatment. Before a definitive treatment, dilatation was performed in 11 cases (61%) and stenting in one other (5.6%). Laser diode therapy was used in 11 patients including 2 cases having postoperative recurrence. Tracheal resection and reconstruction wasperformed in 11 cases (61%) having extensive and severe stenoses with involvement of tracheal cartilage.Conclusion : Acquired tracheal stenoses represent a serious complication with high morbidity. If tracheal resection and reconstruction remains the gold standard treatment, endoscopy represents now a major alternative in their management. Nevertheless, prevention should be considered, given that most stenoses are iatrogenic due to traumatic or prolongedintubations

Update of alien fauna and new records from Tunisian marine waters

An updated inventory of alien marine fauna in coastal and offshore Tunisian waters is presented. Records were compiled from scientific and ‘grey’ publications, presentations at scientific meetings, theses presented in fulfillment of requirements towards MSc and PhD degrees, websites and personal observations. 136 alien species were recorded in Tunisian waters, 60 records in northern coasts, West Mediterranean and 76 in central and southern coasts, Central Mediterranean. Nearly half of the first sightings in Tunisian waters took place in the Gulf of Gabès. The dominant taxa are Crustancean (24%), Molluscs (23%), Fishes (19%) and Annelida (13%). Twenty one species previously reported as aliens, were upon consideration, reclassified as range-expanding Atlantic species. Amathia verticillata, previously considered native to the Mediterranean, is reclassified as pseudoindigenous. Twenty one alien species are newly recorded from Tunisia, including 5 fish species, 5 polychaetes, 4 crustaceans, 4 molluscs, and one each schyphozoan, bryozoan and tunicate. The findings of Gibberulus gibberulus albus, Morula aspera and Calcinus latens, three species new to the Mediterranean, and of Actaedoes tomentosus, reported for the second time in the basin, are described. Species were classified according to their establishment status and their origins. This contribution highlights the dual origin of biological invasion in Tunisian waters (Red Sea and Atlantic), with slightly more species of Red Sea and Indo-Pacific origin (61,76%).  The impact of the alien species in Tunisian waters was discussed

Place et limites de la chirurgie endonasale dans le traitement des mucoceles sinusiennes

Objectif : Préciser les indications et les limites de la chirurgie endonasale dans le traitement des mucocèles sinusiennes.Matériel et méthodes : Il s’agit d’une étude rétrospective à propos de 15 patients colligés sur 13 ans (1994-2006). Tous les patients ont bénéficié d’une endoscopie nasale et d’une TDM du massif facial. Une IRM a été pratiquée dans 10 cas. Le traitement chirurgical comportait une marsupialisation ou une exérèse de la mucocèle. Les voies d’abord étaient endonasales, externes ou combinées, en fonction de l’extension ou de la topographie des lésions. La surveillance en postopératoire a été clinique et radiologique. Résultats : La TDM a montré une atteinte ethmoïdo-frontale (6 cas), maxillaire (5 cas), ethmoïdale isolée (2 cas), frontale isolée (1 cas) et sphénoïdale (1 cas). L’IRM a montré une extension orbitaire dans 7 cas et endocrânienne dans 3 cas. La voie d’abord chirurgicale était endonasale exclusive dans 12 cas. Une voie combinée (endonasale et externe) a été nécessaire chez un patient ayant une atteinte frontale isolée et un autre ayant une atteinte ethmoïdo-frontale. Un patient ayant une mucocèle maxillaire latérale a été opéré par voie de Caldwell-Luc. Aucune récidive n’a été notée avec un recul moyen de 14 mois. Conclusion : La chirurgie endonasale représente la technique de choix dans le traitement des mucocèles sinusiennes et donne de bons résultats à long terme. Le siège et l’extension des mucocèles représentent les principaux facteurs déterminants dans le choix de la voie d’abord

昆虫の生理および行動の統合性におけるセロトニン受容体の機能

博士（学術）神戸大

Mother-to-Infant Transmission of Intestinal Bifidobacterial Strains Has an Impact on the Early Development of Vaginally Delivered Infant's Microbiota

Objectives: Bifidobacterium species are one of the major components of the infant's intestine microbiota. Colonization with bifidobacteria in early infancy is suggested to be important for health in later life. However, information remains limited regarding the source of these microbes. Here, we investigated whether specific strains of bifidobacteria in the maternal intestinal flora are transmitted to their infant's intestine. Materials and Methods: Fecal samples were collected from healthy 17 mother and infant pairs (Vaginal delivery: 12; Cesarean section delivery: 5). Mother's feces were collected twice before delivery. Infant's feces were collected at 0 (meconium), 3, 7, 30, 90 days after birth. Bifidobacteria isolated from feces were genotyped by multilocus sequencing typing, and the transitions of bifidobacteria counts in infant's feces were analyzed by quantitative real-time PCR. Results: Stains belonging to Bifidobacterium adolescentis, Bifidobacterium bifidum, Bifidobacterium catenulatum, Bifidobacterium longum subsp. longum, and Bifidobacterium pseudocatenulatum, were identified to be monophyletic between mother's and infant's intestine. Eleven out of 12 vaginal delivered infants carried at least one monophyletic strain. The bifidobacterial counts of the species to which the monophyletic strains belong, increased predominantly in the infant's intestine within 3 days after birth. Among infants delivered by C-section, monophyletic strains were not observed. Moreover, the bifidobacterial counts were significantly lower than the vaginal delivered infants until 7 days of age. Conclusions: Among infants born vaginally, several Bifidobacterium strains transmit from the mother and colonize the infant's intestine shortly after birth. Our data suggest that the mother's intestine is an important source for the vaginal delivered infant's intestinal microbiota

Novel, Meso-Substituted Cationic Porphyrin Molecule for Photo-Mediated Larval Control of the Dengue Vector Aedes aegypti

Dengue is a life-threatening viral disease of growing importance, transmitted by Aedes mosquito vectors. The control of mosquito larvae is crucial to contain or prevent disease outbreaks, and the discovery of new larvicides able to increase the efficacy and the flexibility of the vector control approach is highly desirable. Porphyrins are a class of molecules which generate reactive oxygen species if excited by visible light, thus inducing oxidative cell damage and cell death. In this study we aimed at assessing the potential of this photo-mediated cytotoxic mechanism to kill Aedes (Stegomyia) aegypti mosquito larvae. The selected porphyrin molecule, meso-tri(N-methylpyridyl),meso-mono(N-tetradecylpyridyl)porphine (C14 for simplicity), killed the larvae at doses lower than 1 µM, and at light intensities 50–100 times lower than those typical of natural sunlight, by damaging their intestinal tissues. The physicochemical properties of C14 make it easily adsorbed into organic material, and we exploited this feature to prepare an ‘insecticidal food’ which efficiently killed the larvae and remained active for at least 14 days after its dispersion in water. This study demonstrated that photo-sensitizing agents are promising tools for the development of new larvicides against mosquito vectors of dengue and other human and animal diseases

Is multiple sclerosis a length-dependent central axonopathy? The case for therapeutic lag and the asynchronous progressive MS hypotheses

Trials of anti-inflammatory therapies in non-relapsing progressive multiple sclerosis (MS) have been stubbornly negative except recently for an anti-CD20 therapy in primary progressive MS and a S1P modulator siponimod in secondary progressive MS. We argue that this might be because trials have been too short and have focused on assessing neuronal pathways, with insufficient reserve capacity, as the core component of the primary outcome. Delayed neuroaxonal degeneration primed by prior inflammation is not expected to respond to disease-modifying therapies targeting MS-specific mechanisms. However, anti-inflammatory therapies may modify these damaged pathways, but with a therapeutic lag that may take years to manifest. Based on these observations we propose that clinically apparent neurodegenerative components of progressive MS may occur in a length-dependent manner and asynchronously. If this hypothesis is confirmed it may have major implications for the future design of progressive MS trials

New Mediterranean Biodiversity Records (July 2016)

This contribution forms part of a series of collective articles published regularly in Mediterranean Marine Science that report on new biodiversity records from the Mediterranean basin. The current article presents 51 geographically distinct records for 21 taxa belonging to 6 Phyla, extending from the western Mediterranean to the Levantine. The new records, per country, are as follows: Spain: the cryptogenic calcareous sponge Paraleucilla magna is reported from a new location in the Alicante region. Algeria: the rare Atlanto-Mediterranean bivalve Cardium indicum is reported from Annaba. Tunisia: new distribution records for the Indo-Pacific lionfish Pterois miles from Zembra Island and Cape Bon. Italy: the ark clam Anadara transversa is reported from mussel cultures in the Gulf of Naples, while the amphipod Caprella scaura and the isopods Paracerceis sculpta and Paranthura japonica are reported as associated to the –also allochthonous–bryozoan Amathia verticillata in the Adriatic Sea; in the latter region, the cosmopolitan Atlantic tripletail Lobotes surinamensisis also reported, a rare finding for the Mediterranean. Slovenia: a new record of the non-indigenous nudibranch Polycera hedgpethi in the Adriatic. Greece: several new reports of the introduced scleractinian Oculina patagonica, the fangtooth moray Enchelycore anatina, the blunthead puffer Sphoeroides pachygaster (all Atlantic), and the lionfish Pterois miles (Indo-Pacific) suggest their ongoing establishment in the Aegean Sea; the deepest bathymetric record of the invasive alga Caulerpa cylindracea in the Mediterranean Sea is also registered in the Kyklades, at depths exceeding 70 m. Turkey: new distribution records for two non indigenous crustaceans, the blue crab Callinectes sapidus (Atlantic origin) and the moon crab Matuta victor (Indo-Pacific origin) from the Bay of Izmir and Antalya, respectively; in the latter region, the Red Sea goatfish Parupeneus forsskali, is also reported. Lebanon: an array of records of 5 alien and one native Mediterranean species is reported by citizen-scientists; the Pacific jellyfish Phyllorhiza punctata and the Indo-Pacific teleosteans Tylerius spinosissimus, Ostracion cubicus, and Lutjanus argentimaculatus are reported from the Lebanese coast, the latter notably being the second record for the species in the Mediterranean Sea since 1977; the native sand snake-eel Ophisurus serpens, rare in the eastern Mediterranean, is reported for the first time from Lebanon, this being its easternmost distribution range; finally, a substantial number of sightings of the lionfish Pterois miles further confirm the current establishment of this lessepsian species in the Levantine

Institutional and behaviour-change interventions to support COVID-19 public health measures: a review by the Lancet Commission Task Force on public health measures to suppress the pandemic

The Lancet COVID-19 Commission Task Force for Public Health Measures to Suppress the Pandemic was launched to identify critical points for consideration by governments on public health interventions to control coronavirus disease 2019 (COVID-19). Drawing on our review of published studies of data analytics and modelling, evidence synthesis and contextualisation, and behavioural science evidence and theory on public health interventions from a range of sources, we outline evidence for a range of institutional measures and behaviour-change measures. We cite examples of measures adopted by a range of countries, but especially jurisdictions that have, thus far, achieved low numbers of COVID-19 deaths and limited community transmission of severe acute respiratory syndrome coronavirus 2. Finally, we highlight gaps in knowledge where research should be undertaken. As countries consider long-term measures, there is an opportunity to learn, improve the response and prepare for future pandemics.publishedVersio