Synthesis and characterization of hybrid films from hyperbranched polyester using a sol–gel process

Hybrid organic/inorganic materials were prepared by an in situ sol–gel process using tetraethoxysilane (TEOS) in the presence of hyperbranched polyester. The influences of hyperbranched polyester molar mass as well as the amount of TEOS were examined. The condensation degree was characterized by solid state ²⁹Si NMR. The combination of solubility tests, calcination tests, SAXS and dynamic mechanical analysis allowed us to investigate the hybrid material nanostructure. The results show high compatibility between the inorganic silica phase and the organic polymer phase, due to the spherical shape of the hyperbranched polymer and its numerous hydroxyl groups. As a consequence, a continuous inorganic phase was formed even with a low silica precursor content without any macroscopic phase separation. These hybrid materials have a high T_g and high storage modulus even at an elevated temperature combined with improved thermal stability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39830.     

Tensile and water barrier properties of cassava starch composite films reinforced by synthetic zeolite and beidellite

Composites films were prepared by the casting method using native cassava starch plasticized with glycerol and 3D or 2D synthetic fillers i.e. Beta zeolite and Na-beidellite type 2:1 phyllosilicate. Special attention was paid to the effect of the filler contents and type on the mechanical and barrier properties. It was shown that films reinforced with lyophilized Beta zeolite presented both high water solubility (WS) and water vapor permeability (WVP) values than the pristine starch whereas an improvement on the WVP was found for composites prepared from Na-beidellite or from non lyophilized Beta zeolite. For the two types of fillers, a drastic increase of the mechanical properties (especially in the Young’s modulus) was observed.     

Simulators for medical training: application to vascular ultrasound imaging

Whilst computers are more and more used in the medical and surgical domains, medical education is still very conservative. However, new information technology could bring a lot to this area. In particular, simulators are of paramount interest: they would allow one both to experiment with surgical or imaging techniques for a wide range of pathologies without the need for patients and to quantitatively evaluate the trainees' performances. Ultrasound imaging is a typical area where virtual reality may change educational uses. This paper describes an ultrasound imaging simulator dedicated to the training of physicians for the detection of deep venous thromboses of the lower limbs. Like this one, a lot of other pathologies of soft tissue are diagnosed using ultrasound imaging. Because this examination is difficult and operator‐dependent, developing a simulator is very useful to give common databases of pathological samples on which physicians can both experiment with image acquisition and evaluate their understanding of clinical cases. Real‐time simulation is mandatory. An ultrasound imaging simulator has been developed and is being tested. This paper presents the hardware and software components of the simulator and describes the status of this project. Copyright © 2000 John Wiley & Sons, Ltd.