372 research outputs found

    Scaled-up expansion of equine cord blood mesenchymal stem cells (MSCs) from stirred suspension bioreactors to 100mL computer controlled stirred suspension bioreactors using computational fluid dynamic modeling

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    Musculoskeletal injuries are the leading cause of lameness and loss of performance in horses and conventional treatments are often associated with high rates of re-injury. Mesenchymal Stem Cells (MSCs) have shown promise for the treatment of such injuries in horses. Currently, the majority of studies are focused on the use of either bone-marrow derived or adipose-derived MSCs. However, equine cord-blood derived MSCs (eCB-MSCs) also provide a promising alternative, due to their high proliferation potential, ability to differentiate towards the chondrogenic lineage, and comparable immune-modulatory properties. Static adherent culture of eCB-MSCs has limited potential to produce sufficient cell numbers for large-scale research studies and possible commercial distribution. Expansion of cells in stirred suspension bioreactors using microcarriers as a scaffold has the potential to generate a large number of cells, using a significantly smaller space, under highly controlled conditions, with reduced time, labour, and monetary requirements. A robust protocol is required for the expansion of eCB-MSCs for use in large research studies and commercial applications. Initially, the hydrodynamic environment in the 10mL and the 100mL bioreactors was modeled using COMSOL Multiphysics software. The volume distributions of shear stress and energy dissipation rate in the bioreactors were calculated and used to determine the operating conditions that would create similar conditions within both scales of bioreactors. Next, eCB-MSCs were expanded in 10mL stirred suspension bioreactors and run at 60rpm and 80rpm with two different impeller geometries: paddles and rounded edges. The bioreactors were loaded at 4500 cells/cm2, and 2g/L microcarriers. The cells at different operating conditions in the 10mL bioreactors achieved varying population doubling times ranging from 0.8d to 1.1d with an average of 0.9d and initial cell attachment ranging from 5000 cells/cm2 to 7700 cells/cm2. The different speeds and geometries produced varying results with maximum attached cell densities from 35,000 to 50,000 cells/cm2 in the bioreactors, compared to maximum cell densities of 44,000 cells/cm2 achieved instatic growth. The expansion of eCB-MSCs was then scaled up in 100mL stirred suspension bioreactors with no direct pH or dissolved oxygen control, using 4500 cells/cm2 and 2g/L microcarriers, with a speed of 40rpm. At this larger scale, the initial cell attachment was 6900 cells/cm2 compared to 6300 cells/cm2 for the 10mL bioreactor. With respect to initial cell attachment, the 100mL bioreactor at 40rpm was most similar to the condition of 80rpm with round edge impeller geometry. The highest attached cell density in the 100 mL vessel was 70,000 cells/cm2. The 100mL uncontrolled bioreactor at 40rpm achieved the most similar results to the 10mL bioreactor run at 60rpm with paddled geometry, with respect to population doubling time with a doubling time of 0.93d for the 10mL bioreactor compared to 0.92d for the 100mL bioreactor. Finally, the eCB-MSCs were expanded in 100mL stirred suspension bioreactors at 4500 cells/cm2, 2g/L and 40rpm with pH and oxygen controlled at 7.4 and 21% DO, respectively, using the DASGIP bioreactor control system. This series of experiments revealed that eCB-MSCs can be expanded in stirred suspension bioreactors

    Assimilation of radar altimeter data in numerical wave models: an impact study in two different wave climate regions

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    An operational assimilation system incorporating significant wave height observations in high resolution numerical wave models is studied and evaluated. In particular, altimeter satellite data provided by the European Space Agency (ESA-ENVISAT) are assimilated in the wave model WAM which operates in two different wave climate areas: the Mediterranean Sea and the Indian Ocean. The first is a wind-sea dominated area while in the second, swell is the principal part of the sea state, a fact that seriously affects the performance of the assimilation scheme. A detailed study of the different impact is presented and the resulting forecasts are evaluated against available buoy and satellite observations. The corresponding results show a considerable improvement in wave forecasting for the Indian Ocean while in the Mediterranean Sea the assimilation impact is restricted to isolated areas

    Cloud-resolving simulations of mercury scavenging and deposition in thunderstorms

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    This study examines dynamical and microphysical features of convective clouds that affect mercury (Hg) wet scavenging and concentrations in rainfall. Using idealized numerical model simulations in the Regional Atmospheric Modeling System (RAMS), we diagnose vertical transport and scavenging of soluble Hg species – gaseous oxidized mercury (GOM) and particle-bound mercury (HgP), collectively Hg(II) – in thunderstorms under typical environmental conditions found in the Northeast and Southeast United States (US). Mercury scavenging efficiencies from various initial altitudes are diagnosed for a case study of a typical strong convective storm in the Southeast US. Assuming that soluble mercury concentrations are initially vertically uniform, the model results suggest that 60% of mercury deposited to the surface in rainwater originates from above the boundary layer (> 2 km). The free troposphere could supply a larger fraction of mercury wet deposition if GOM and HgP concentrations increase with altitude. We use radiosonde observations in the Northeast and Southeast to characterize three important environmental characteristics that influence thunderstorm morphology: convective available potential energy (CAPE), vertical shear (0–6 km) of horizontal wind (SHEAR) and precipitable water (PW). The Southeast US generally has lower SHEAR and higher CAPE and PW. We then use RAMS to test how PW and SHEAR impact mercury scavenging and deposition, while keeping the initial Hg(II) concentrations fixed in all experiments. We found that the mercury concentration in rainfall is sensitive to SHEAR with the nature of sensitivity differing depending upon the PW. Since CAPE and PW cannot be perturbed independently, we test their combined influence using an ensemble of thunderstorm simulations initialized with environmental conditions for the Northeast and Southeast US. These simulations, which begin with identical Hg(II) concentrations, predict higher mercury concentrations in rainfall from thunderstorms forming in the environmental conditions over the Southeast US compared to the Northeast US. A final simulation of a stratiform rain event produces lower mercury concentrations than in thunderstorms forming in environments typical of the Southeast US. The stratiform cloud scavenges mercury from the lowest ~ 4 km of the atmosphere, while thunderstorms scavenge up to ~ 10 km

    Modelling the chemically aged and mixed aerosols over the eastern central Atlantic Ocean – potential impacts

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    Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size distribution, using chemistry-transport models, satellite data and in situ measurements. We focus on August 2005, a period with intense hurricane and tropical storm activity over the Atlantic Ocean. A mixture of anthropogenic (sulphates, nitrates), natural (desert dust, sea salt) and chemically aged (sulphate and nitrate on dust) aerosols is found entering the hurricane genesis region, most likely interacting with clouds in the area. Results from our modelling study suggest rather small amounts of accumulation mode desert dust, sea salt and chemically aged dust aerosols in this Atlantic Ocean region. Aerosols of smaller size (Aitken mode) are more abundant in the area and in some occasions sulphates of anthropogenic origin and desert dust are of the same magnitude in terms of number concentrations. Typical aerosol number concentrations are derived for the vertical layers near shallow cloud formation regimes, indicating that the aerosol number concentration can reach several thousand particles per cubic centimetre. The vertical distribution of the aerosols shows that the desert dust particles are often transported near the top of the marine cloud layer as they enter into the region where deep convection is initiated. The anthropogenic sulphate aerosol can be transported within a thick layer and enter the cloud deck through multiple ways (from the top, the base of the cloud, and by entrainment). The sodium (sea salt related) aerosol is mostly found below the cloud base. The results of this work may provide insights relevant for studies that consider aerosol influences on cloud processes and storm development in the Central Atlantic region

    Hindcast of oil-spill pollution during the Lebanon crisis in the Eastern Mediterranean, July–August 2006

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    MOON (Mediterranean Operational Oceanography Network http://www.moon-oceanforecasting.eu) pro- vides near-real-time information on oil-spill detection (ocean color and SAR) and predictions [ocean fore- casts (MFS and CYCOFOS) and oil-spill predictions (MEDSLIK)]. We employ this system to study the Lebanese oil-pollution crisis in summer 2006 and thus to assist regional and local decision makers in Europe, regionally and locally. The MEDSLIK oil-spill predictions obtained using CYCOFOS high-resolution ocean fields are compared with those obtained using lower-resolution MFS hydrodynamics, and both are validated against satellite observations. The predicted beached oil distributions along the Lebanese and Syrian coasts are compared with in situ observations. The oil-spill predictions are able to simulate the northward movement of the oil spill, with the CYCO- FOS predictions being in better agreement with satellite observations. Among the free MEDSLIK param- eters tested in the sensitivity experiments, the drift factor appears to be the most relevant to improve the quality of the results.The paper was produced using the INGV MFS forecasting-sys- tem product and the OC-UCY CYCOFOS forecasting-system prod- ucts. The MODIS satellite data products were processed at the GOS-CNR-ISAC Rome laboratory using the SeaDAS software devel- oped by NASA GSFC, Greenbelt, Maryland, the HDFLook software developed by The Laboratoire d’Optique Atmosphérique, Univer- sity of Lille, France, and the MS2GT tool box developed by the Uni- versity of Colorado. Procedures for oil-spill detection were developed in the ENVI environment. Processed ENVISAT-ASAR data were made available by Telespazio and JRC. Part of this work was carried out with the support of the PRIMI project (ASI Contract No. I/094/06/0) financed by the Italian Space Agency (ASI).In press4.6. Oceanografia operativa per la valutazione dei rischi in aree marineJCR Journalreserve

    Hindcast of oil-spill pollution during the Lebanon crisis in the Eastern Mediterranean, July–August 2006

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    MOON (Mediterranean Operational Oceanography Network http://www.moon-oceanforecasting.eu) provides near-real-time information on oil-spill detection (ocean color and SAR) and predictions [ocean forecasts (MFS and CYCOFOS) and oil-spill predictions (MEDSLIK)]. We employ this system to study the Lebanese oil-pollution crisis in summer 2006 and thus to assist regional and local decision makers in Europe, regionally and locally. The MEDSLIK oil-spill predictions obtained using CYCOFOS high-resolution ocean fields are compared with those obtained using lower-resolution MFS hydrodynamics, and both are validated against satellite observations. The predicted beached oil distributions along the Lebanese and Syrian coasts are compared with in situ observations. The oil-spill predictions are able to simulate the northward movement of the oil spill, with the CYCOFOS predictions being in better agreement with satellite observations. Among the free MEDSLIK parameters tested in the sensitivity experiments, the drift factor appears to be the most relevant to improve the quality of the results.Published140–153JCR Journalrestricte

    Hindcast of Oil Spill Pollution during the Lebanon Crisis, July-August 2006

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    The Mediterranean Operational Oceanography Network (MOON ) provides near-real-time information on oil spill detection and predictions that have been used during the Lebanese oil pollution crisis in summer 2006. A MOON decision support system for oil spill monitoring and prediction comprising ocean colour satellite and SAR images, ocean current forecast (MFS-Mediterranean Forecasting System and CYCOFOS-CYprus Coastal Ocean Forecasting & Observing System) and the MEDSLIK oil spill model has been developed. The oil spill predictions obtained with MEDSLIK coupled to the CYCOFOS high-resolution ocean fields are compared with the oil spill predictions obtained using the lower resolution MFS hydrodynamics and both are validated against satellite observations. The predicted beached oil quatity along the Lebanese and Syrian coasts are compared with the in-situ observations. It is found that predictions with both CYCOFOS and MFS ar capable to simulate the northward movement of the oil, with the higher resolution CYCOFOS predictions in better agreement with satellite observations. Among the free MEDSLIK oil spill parameters tested in the sensitivity experiments there are the wind corrections (wind factor and angle) and the depth of coupling between eulerian fields and wind correction. Among them the drift factor appeared the most relevant in order to improve the quality of results suggesting that operational models such as MFS and CYCOFOS still lack of enought resolution and physical process at the air-sea interface. The oil moved from Lat 33°40'N Lon 35°24.75'E northward toward Syria, which was reached in 10 days at Lat 34° 38.451'N Lon 35° 58.377'E; the oil movement is followed up to August 6 when the oil reached 35.5°N.Not submitted4.6. Oceanografia operativa per la valutazione dei rischi in aree marineJCR Journalope

    Cell Therapy in Veterinary Medicine as a Proof-of-Concept for Human Therapies: Perspectives From the North American Veterinary Regenerative Medicine Association

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    In the past decade, the potential to translate scientific discoveries in the area of regenerative therapeutics in veterinary species to novel, effective human therapies has gained interest from the scientific and public domains. Translational research using a One Health approach provides a fundamental link between basic biomedical research and medical clinical practice, with the goal of developing strategies for curing or preventing disease and ameliorating pain and suffering in companion animals and humans alike. Veterinary clinical trials in client-owned companion animals affected with naturally occurring, spontaneous disease can inform human clinical trials and significantly improve their outcomes. Innovative cell therapies are an area of rapid development that can benefit from non-traditional and clinically relevant animal models of disease. This manuscript outlines cell types and therapeutic applications that are currently being investigated in companion animals that are affected by naturally occurring diseases. We further discuss how such investigations impact translational efforts into the human medical field, including a critical evaluation of their benefits and shortcomings. Here, leaders in the field of veterinary regenerative medicine argue that experience gained through the use of cell therapies in companion animals with naturally occurring diseases represent a unique and under-utilized resource that could serve as a critical bridge between laboratory/preclinical models and successful human clinical trials through a One-Health approach

    Short-term Wind Power Forecasting Using Advanced Statistical Methods

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    Disponible sur : http://anemos.cma.fr/download/publications/pub_2006_paper_EWEC06_WP3statistical.pdfInternational audienceThis paper describes some of the statistical methods considered in the ANEMOS project for short-termforecasting of wind power. The total procedure typically involves various steps, and all these steps are described in the paper. These steps include downscaling from reference MET forecasts to the actual wind farm, wind farm power curve models, dynamical models for prediction of wind power or wind speed, estimating the uncertainty of the wind power forecast, and finally, methods for upscaling are considered. The upscaling part considers how a total regional production can be estimated using a small number of reference wind farms. Keywords: Forecasting, power curve, wind farmpower curve, upscaling, uncertainty estimation, probabilistic forecasts, adaptation
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