Time-resolved diffuse optical tomography for non-invasive flap viability assessment: Pre-clinical tests on rats

We present a new setup for time-resolved diffuse optical tomography based on multiple source-detector acquisitions analysed by means of the Mellin-Laplace transform. The proposed setup has been used to perform pre-clinical measurements on rats in order to show its suitability for non-invasive assessment of flap viability

New thermoplastic polyurethane elastomers based on sulfur-containing chain extenders

New thermoplastic polyurethane elastomers (TPUs) were synthesized by a one-step melt polyaddition from poly(oxytetramethylene) diol of M¯n = 2000 g/mol as the soft segment, 1,1’-methanediylbis(4-isocyanatocyclohexane) (HMDI, Desmodur W®), and 2,2’-[methanediylbis(benzene-4,1-diylmethanediylsulfanediyl)]diethanol (diol E) or 6,6’-[methanediylbis(benzene-4,1-diylmethanediylsulfanediyl)]dihexane-1-ol (diol H) as unconventional chain extenders. The effects of the kind and amount of the polymer diol and chain extender used on the structure and properties of the polymers were studied. The polymers were examined by Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, Shore hardness and tensile testing. Both the adhesive and optical properties were determinated for a selected polymer. The obtained TPUs were amorphous, colorless, high-molar-mass materials. It was observed that the polymers with the diol E showed higher hardness and tensile strengths but smaller elongations at break than diol H-based ones. All of the polymers exhibited a relatively good thermal stability. Their temperatures of 5% mass loss were in the range 312-338°C

Time-domain diffuse optical tomography processing by using the mellin-laplace transform

International audienceWe investigate the use of the Mellin–Laplace transform for reconstructing optical parameters from time-resolved optical tomography in diffusive media. We present here its definition, its mathematical properties, and its sensitivity to variations of optical properties. The method was validated on two-dimensional reconstructions from simulation in the reflection geometry. We conclude that reconstructions based on the Mellin–Laplace transform are more robust to noise than the methods using first moments

Design of an optimized Time-Resolved diffuse optical tomography probe to achieve deep absorption contrast reconstruction in a cylindrical geometry

International audienceWe design a Time-Resolved (TR) instrumentation coupled with a reconstruction method based on Mellin-Laplace Transform (MLT) to accurately assess in depth absorption and diffusion maps of a cylindrical diffusive medium. To deal with experimental large TR dataset, MLT processing is handled without expressing the sensitivity matrix. Moreover an optimization of the TR probe geometry is performed to limit the number of measurements while keeping the sensitivity of the system. Simulations show how to optimize the probe geometry for specific inclusions depth given a background diffusing medium. These results lead to an experimental bench we use to perform experimental validations. This includes a femtosecond laser coupled with an HRI and a CCD camera

Detection and localization in depth with TR-DOT based on Mellin Laplace transforms

International audienc

Trends and values of 'Land for Wildlife' programs for private land conservation

The Land for Wildlife program started in Victoria in 1981 as a voluntary program with the broad aim of supporting landholders in providing habitat for wildlife on their property. The program has since spread across Australia and is implemented in a range of guises, through a variety of governance approaches. This research collected qualitative and quantitative data on Land for Wildlife programs across Australia to conduct the first national review. Data were gathered on changes in program membership to assess different participation trends. In addition, phone interviews with Land for Wildlife coordinators throughout Australia were conducted to explore how the programs are positioned in delivering biodiversity outcomes in a range of different regions. Over 14,000 properties covering 2.3 million ha are currently registered under Land for Wildlife programs. with at least 500,000 ha of habitat managed for conservation. Limited resources present a large challenge faced by a number of programs, with generally low funding and staffing resulting in restricted biodiversity focus and conservation outcomes. We suggest options to enhance the programs and propose future research directions

Tomographie Optique Diffuse résolue en temps en géométrie de réflexion: images de contraste d'absorption en profondeur

Detecting and localizing precisely contrast in depth is the major challenge of reflectance Diffuse Optical Tomography. We present a dedicated time-resolved instrumentation and first experimental results using a method based on the Mellin-Laplace Transform to process the acquired signals. We validate the use of this method with results of images of absorption coefficients reconstructed from phantom measurements

Fluorescence tomography applied to prostate cancer diagnosis using white pulsed laser

International audienceProstate cancer diagnosis is based on PSA rate measurement and ultrasound guided biopsy. Recently criticized for its lack of specificity, new approaches are currently investigated: MRI, elastography, TEP, NIRS and Time Resolved (TR) fluorescence tomography. The advantage of TR fluorescence tomography relies on its good complementarity with the standard ultrasound protocol and on the possible localization of prostate tumors marked by specific probes. After a first TR system based on a bulky titanium-sapphire laser, we designed a new one taking advantage of a more compact white pulsed laser (supercontinuum). The improved compactness is now fully compatible with clinical environment. The light, filtered by two linear variable filters to select a 770±20 nm window, is driven to the transrectal probe which also collects the fluorescence light emitted by the marker. The signal is detected by photomultipliers connected to TCSPC boards. A reconstruction algorithm based on intensities and time of flight allows a fast localization of the fluorophore. We compared the performances of the new white laser system to the previous titanium-sapphire on prostate mimicking phantoms. The laser power delivered on the phantom by the new laser appeared to be suitable to fluorescence measurements, just below cutaneous maximum permitted exposure. The new system allowed us to localize fluorescent inclusions of a fluorescent nanoemulsion at fixed positions inside a prostate mimicking phantom