Modelling dehydration and quality degradation of maize during fluidized-bed drying

in Journal of Food Engineering (2010), 100(3), 527-534

At harvest time, maize (Zea mays L.) has a moisture content too high to be stored, and has to be dried. To control the previous termdryingnext term impact on maize characteristics, it is necessary to ... [more ▼]

At harvest time, maize (Zea mays L.) has a moisture content too high to be stored, and has to be dried. To control the previous termdryingnext term impact on maize characteristics, it is necessary to accurately know the spatial distribution of temperature and moisture content in the kernel, and the kinetics of quality loss in relation to these two factors. To this end, a physical model of heat and mass transfer in a maize kernel was designed. The Fick and Fourier equations were solved by the finite element method (FEM). The real 3D geometry of maize was obtained by NMR imaging and then used to build the mesh needed for the FEM computations. The model correctly describes the evolutions of maize moisture and salt-soluble protein content during fluidized-bed previous termdryingnext term with a constant previous termdryingnext term air temperature between 50 °C and 100 °C. [less ▲]

Investigation of non-covalent interactions between paramagnetic complexes and human serum albumin by electrospray mass spectrometry

in Rapid Communications in Mass Spectrometry : RCM (2004), 18(17), 1919-1924

Stable gadolinium(III) chelates are nowadays routinely used as contrast agents for magnetic resonance imaging (MRI). Their non-covalent binding to human serum albumin (HSA) has shown to improve their ... [more ▼]

Stable gadolinium(III) chelates are nowadays routinely used as contrast agents for magnetic resonance imaging (MRI). Their non-covalent binding to human serum albumin (HSA) has shown to improve their efficacy. Non-covalent interactions lead to complex formation that can be quantified by several techniques that are mostly tedious and time-consuming. In this study, electrospray ionization mass spectrometry (ESI-MS) was used to investigate the interaction between HSA and several gadolinium(III) complexes. The results were compared with those obtained in the liquid phase. Four gadolinium complexes were investigated: Gd-DTPA 1, Gd-C4Me-DTPA 2, Gd-EOB-DTPA 3, and MP-2269 4. Relaxometry studies show that complexes 1 and 2 have no significant affinity for HSA, while complexes 3 and 4 have increasing affinities for the protein. 1:1 and 1:2 complexes between HSA and MP-2269 were detected by ESI-MS for a twofold excess of the contrast agent, whereas a ligand/protein molar ratio of 4:1 was necessary to observe a 1:1 stoichiometry for Gd-EOB-DTPA, an observation that is in good agreement with the known weaker affinity of the contrast agent for the protein. At a fourfold molar excess, no supramolecular complex was observed for Gd-DTPA I and Gd-C4Me-DTPA 2; a tenfold molar excess was necessary to detect a 1:1 complex, confirming the very weak affinity of these contrast agents for HSA. [less ▲]