Passive element enriched photoacoustic computed tomography (PER PACT) for simultaneous imaging of acoustic propagation properties and light absorption\ud

We present a ‘hybrid’ imaging approach which can image both light absorption properties and acoustic transmission properties of an object in a two-dimensional slice using a computed tomography (CT) photoacoustic imager. The ultrasound transmission measurement method uses a strong optical absorber of small cross-section placed in the path of the light illuminating the sample. This absorber, which we call a passive element acts as a source of ultrasound. The interaction of ultrasound with the sample can be measured in transmission, using the same ultrasound detector used for photoacoustics. Such measurements are made at various angles around the sample in a CT approach. Images of the ultrasound propagation parameters, attenuation and speed of sound, can be reconstructed by inversion of a measurement model. We validate the method on specially designed phantoms and biological specimens. The obtained images are quantitative in terms of the shape, size, location, and acoustic properties of the examined heterogeneitie

Production and characterization of monoclonal antibodies raised against recombinant human granzymes A and B and showing cross reactions with the natural proteins

The human serine proteases granzymes A and B are expressed in cytotoplasmic granules of activated cytotoxic T lymphocytes and natural killer cells. Recombinant granzyme A and granzyme B proteins were produced in bacteria, purified and then used to raise specific mouse monoclonal antibodies. Seven monoclonal antibodies (mAb) were raised against granzyme A, which all recognized the same or overlapping epitopes. They reacted specifically in an immunoblot of interleukin-2 (IL-2) stimulated PBMNC with a disulfide-linked homodimer of 43 kDa consisting of 28 kDa subunits. Seven mAb against granzyme B were obtained, which could be divided into two groups, each recognizing a different epitope. On an immunoblot, all mAb reacted with a monomer of 33 kDa protein. By immunohistochemistry, these mAb could be used to detect granzymes A and B expression in activated CTL and NK cells. The availability of these mAb may facilitate studies on the role of human cytotoxic cells in various immune reactions and may contribute to a better understanding of the role of granzmes A and B in the cytotoxic response in vivo

Using remotely sensed solar radiation data for reference evapotranspiration estimation at a daily time step

International audienceSolar radiation is an important climatic variable for assessing reference evapotranspiration (E0), but it is seldom available in weather station records. Meteosat satellite images processed with the Heliosat-2 method provide the HelioClim-1 database, which displays spatialized solar radiation data at a daily time step for Europe and Africa. The aim of the present work was to investigate the interest of satellite-sensed solar radiation for E0 calculation, where air temperature is the sole local weather data available. There were two study areas in Southern France. One (Southwest, SW) is characterized by Oceanic climate and the other (Southeast, SE) by Mediterranean climate. A data set of daily values for 19 weather stations spanning five years (2000–2004) was used. First, a sensitivity analysis of the Penman–Monteith formula to climate input variables was performed, using the Sobol' method. It shows that E0 is mainly governed by solar radiation during summer, and by wind speed during winter. Uncertainties of HelioClim-1 solar radiation data and their repercussions on E0 formulae were evaluated, using the FAO-56 Penman–Monteith formulae (PM) and radiation-based methods (Turc, TU; Priestley–Taylor, PT and Hargreaves-Radiation, HR). It was shown that HelioClim-1 data slightly underestimate solar radiation and provide relative RMSE (root mean square error) of 20% of the mean annual value for SW and 14% for SE. The propagation of HelioClim-1 data uncertainties is small in PM but considerable in radiation methods. Four estimation methods were then compared to PM data: the 1985 Hargreaves formula (HT) based on air temperature only; TU, PT and HR, based on air temperature and satellite-sensed solar radiation. Radiation methods were more precise and more accurate than HT, with RMSE ranging from 0.52 mm to 0.86 mm against 0.67–0.96 mm. These results suggest that using satellite-sensed solar radiation may improve E0 estimates for areas where air temperature is the only available record at ground level

Estimating spatial and temporal variations in solar radiation within Bordeaux winegrowing region using remotely sensed data

International audienceAims: This paper presents a study solar radiation spatial and temporal variations in Bordeaux winegrowing area, for a 20 year period (1986-2005). Methods and results: Solar radiation data was retrieved from the HelioClim-1 database, elaborated from Meteosat satellite images, using the Heliosat-2 algorithm. Daily data was interpolated using ordinary kriging to produce horizontal solar radiation maps at a 500 m resolution. Using a digital elevation model, high resolution daily solar radiation maps with terrain integration were then produced for the period 2001-2005, at a 50 m resolution. The long term (20 years) analysis of solar radiation at low spatial resolution (500 m) showed a west to east decreasing gradient within Bordeaux vineyards. Mean August-to-September daily irradiation values, on horizontal surface, were used to classify Bordeaux winegrowing areas in three zones: low, medium, and high solar radiation areas. This initial zoning was upscaled at 50 m resolution, applying a local correction ratio, based on 2001-2005 solar radiation on inclined surface analysis. Grapevine development and maturation potential of the different zones of appellation of origin of Bordeaux winegrowing area are discussed in relation with this zoning. 2 Conclusions: Solar radiation variability within Bordeaux winegrowing area is mainly governed by terrain slopes and orientations, which induce considerable variations within the eastern part of Bordeaux vineyards. Significance and impact of the study: Solar radiation has a major impact on vineyard water balance, grapevine development and berry ripening. However, irradiation data is seldom available in weather stations records. This paper underline the interest of high resolution cartography of solar radiation, using satellite sensing and terrain effect integration, for agroclimatic studies in viticulture