Agglomeration of gas hydrate in a water-in-oil emulsion: Experimental and modeling studies

International audienceThe formation of gas hydrates in water-in-oil emulsion is investigated at the laboratory pilot scale on a flow loop. The Archimede flow loop (30 m long, and 1 cm diameter) has been built to reproduce the thermodynamic conditions encountered in deep-sea pipelines with a maximum flow rate equal to 3x10-5 m3.s-1. Recently, a Moineau pump has been added in order to maintain the flow at a constant rate, especially after the beginning of crystallization and independently of the rheological characteristics (the flow rate can be varied in the range 2x10-5 m3.s-1 to 14x10-5 m3.s-1). This work presents some preliminary experiments to characterize the flow properties. Also some crystallization experiments were realized in order to understand the coupling between crystallization and rheology by following the size of the agglomerates and the water conversion. When water droplets crystallize to form hydrate particles, an agglomeration phenomenon is evidenced by pressure drop measurements. The agglomeration phenomenon is also detected by a Focused Beam Reflectance Measurements (FBRM) probe and is highlighted by a sharp change in the mean chord length and a spread of the Chord Length Distribution (CLD) to larger chord length

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Agglomération des hydrates de gaz dans les émulsions eau dans huile: étude expérimentale et modélisation

National audienceLa formation d'hydrates de gaz à partir des émulsions d'eau dans l'huile a été étudié sur une unité pilote (boucle de circulation " Archimède " : 30 m de longueur et 1 cm de diamètre, à l'école des mines de Saint-Etienne) permettant de reproduire les conditions thermodynamiques rencontrées dans les conduites pétrolières en mer profonde. Récemment, une pompe Moineau a été ajoutée dans le but de maintenir un écoulement avec une vitesse de circulation constante, particulièrement après que la cristallisation se forme. Lorsque l'eau en suspension se cristallise pour former des particules d'hydrates, un phénomène d'agglomération est mis en évidence par la mesure de la perte de charge. Ce phénomène d'agglomération peut être aussi détecté par l'analyse de la distribution en longueur de corde (CLD) mesurée par une sonde FBRM (Focused Beam Reflectance Measurements). Dans le but d'interpréter les mesures de la CLD, un modèle a été développé. Ce modèle permet de comparer la taille des agrégats à partir des mesures de viscosité et de la CLD. Les résultats obtenus à partir du modèle de Le Ba ont été comparés à ceux donnés par des mesures de la viscosité dans le but de mieux comprendre les propriétés rhéologiques des émulsions. En utilisant la nouvelle configuration de la boucle de circulation, l'effet des additifs antiagglomérants peut être étudié. Ce modèle peut être utilisé pour comprendre le taux de conversion de l'émulsion durant la cristallisation en modifiant les paramètres opératoires: teneur en eau, concentration en additifs, concentration du sel dans l'eau... Les résultats expérimentaux obtenus dans ce travail permettent une meilleure compréhension de la cristallisation en écoulement et contribue à la poursuite du travail de modélisation de ce type de cristallisation par les bilans de population

First assessment of microplastics in offshore sediments along the Lebanese coast, South-Eastern Mediterranean

Highlights: • First abundance of MPs in offshore sediments along South-Eastern Mediterranean • Mean MPs ranged between 1126 ± 1363 MPs/kg. • Most abundant shapes were fibers and films. • Most abundant polymer types were PP and PE. • Coastal landfills and wastewater discharges shaped spatial distribution of MPs. Few studies on microplastics (MPs) in the marine environment have been conducted along the Eastern part of the Mediterranean Sea and even fewer along the Lebanese coast. This study aims to determine MPs contamination for the first-time in coastal and continental shelf sediments collected along the Lebanese shores, South-Eastern Mediterranean Sea. Sediments were collected as transects in 10 sites with a total of 23 samples between 2 and 120 m depth and suspected MPs were assessed by moving farther from land-based sources. Microplastics concentrations ranged between 0 and 4500 MPs/kg of dry sediment (1126 ± 1363 MPs/kg). Polypropylene, polyethylene, polyethylene terephthalate and polystyrene were the polymers identified on micro-Raman. Coastal landfills and raw sewage effluents were identified as the main sources and routes for MPs into the Lebanese coastal marine environment. This study serves as the first database reporting MPs in continental shelf sediments in the South-Eastern Mediterranea

Floating Marine Litter in Eastern Mediterranean From Macro to Microplastics: The Lebanese Coastal Area as a Case Study

<jats:p>Despite emerging and increasing concerns related to marine micro and macroplastics, no systematic surveys have been undertaken yet in the Lebanese marine area. To understand the spatio-temporal variation of plastic litter (macro and microplastics) in the Lebanese marine environment and to determine the sources of pollution, this study investigated the characteristics of plastic pollution in sea surface waters during wet and dry seasons in 22 sites of Beirut and Tyre regions. A total of 23,023 items were identified and assessed according to the shape, color, and concentration; moreover, the risk of microplastics (MPs) contamination was explored based on a risk assessment model. The obtained results demonstrated that the average macroplastics concentration was 0.45 ± 0.6 items/m<jats:sup>3</jats:sup>. The average microplastics concentration was found to be 20.1 ± 21.8 and 3.78 ± 5.2 items/m<jats:sup>3</jats:sup> in spring and fall respectively. During fall, MPs fragments were dominant in Beirut (97%) and Tyre (91%), and no pellets were observed. During spring, filaments were most encountered in Beirut (76.5%). The most dominant marine litter color was blue followed by black and white. The Pollution Load Index (PLI) values showed a moderate contamination of the Lebanese coast with MPs (PLI: 5.79 ± 3.93) except for several sites in Beirut that showed high values of PLI, highlighting the local influence of cities and rivers on MPs concentration. This study serves as an important baseline for understanding the characteristics of the seasonal variation of MPs along the Lebanese marine environment; it will help stakeholders and countries to take proactive and reactive actions to face plastic litter pollution in the Lebanese coastal area.</jats:p&gt

Investigating the permeability of almond cell walls to digestive enzymes

International audienc

A New Method for Microplastics Identification in Copepods

International audienceThis study investigates several methods to identify microplastics (MPs) of small size ranges(<10 μm) in the copepod Eurytemora affinis collected in the Seine estuary (France) andidentified using epifluorescence microscopy and Raman microspectroscopy. In order tocalibrate the methodology, copepods obtained from cultures were used. Firstly, welabelled three types of MPs (i.e., Polystyrene, Polyethylene, and Polylactic acid) withNile Red and confirmed their ingestion by E. affinis with epifluorescence microscopy.Considering the convenient detection of Nile Red labelled MPs using epifluorescenceobservation, we tried to pair this method with Raman microspectroscopy. For this, wedeveloped an enzymatic digestion method consisting of copepods digestion usingProteinase K followed by sonication in order to fragment their cuticle. The lysate wasthen vacuum filtered on black polycarbonate membrane filters that were the mostappropriate for epifluorescence microscopy. Potential MPs were dyed with Nile Reddirectly on the filter, which allowed a relatively rapid visual detection. However, resultsshowed that black polycarbonate membrane filters induced a significant backgroundfluorescence during Raman identification of MPs and hence particles smaller than 10 μmcould not be characterized. In this case, we were not able to link staining method withmicro-Raman for the size range of MPs targeted in this study. Thus, aluminum oxide filterswere tested, and staining method was replaced by a classical observation withstereomicroscopic magnifier to delimit areas of observation for Raman microscopicidentification. Aluminum oxide filters induced less fluorescence, allowing the detectionof MPs (as small as 1 μm diameter) on copepods from laboratory cultures exposed withMPs. We applied this method on copepods collected in the natural environment. Within apool of 20 copepods of three replicates, we identified 17 MPs (average of 0.28 MPs/copepod) composed of eight different polymer types and six colors. These MPscorresponded to 59% of fibres with 14.1 ± 9.4 μm diameter and 391.6 ± 600.4 μmlength along with 41% of fragments with an average diameter of 13.2 μm ± 9.5 μm. Thisstudy reports a novel approach to detect the presence of small particles of MPs ingestedby copepods in the natural environment

Early complementopathy after multiple injuries in humans

After severe tissue injury, innate immunity mounts a robust systemic inflammatory response. However, little is known about the immediate impact of multiple trauma on early complement function in humans. In the present study, we hypothesized that multiple trauma results in immediate activation, consumption, and dysfunction of the complement cascade and that the resulting severe "complementopathy" may be associated with morbidity and mortality. Therefore, a prospective multicenter study with 25 healthy volunteers and 40 polytrauma patients (mean injury severity score = 30.3 ± 2.9) was performed. After polytrauma, serum was collected as early as possible at the scene, on admission to the emergency room (ER), and 4, 12, 24, 120, and 240 h post-trauma and analyzed for the complement profile. Complement hemolytic activity (CH-50) was massively reduced within the first 24 h after injury, recovered only 5 days after trauma, and discriminated between lethal and nonlethal 28-day outcome. Serum levels of the complement activation products C3a and C5a were significantly elevated throughout the entire observation period and correlated with the severity of traumatic brain injury and survival. The soluble terminal complement complex SC5b-9 and mannose-binding lectin showed a biphasic response after trauma. Key fluid-phase inhibitors of complement, such as C4b-binding protein and factor I, were significantly diminished early after trauma. The present data indicate an almost synchronical rapid activation and dysfunction of complement, suggesting a trauma-induced complementopathy early after injury. These events may participate in the impairment of the innate immune response observed after severe trauma