Release Properties of Hydrogels: Water Evaporation from Alginate Gel Beads

Encapsulation in alginate hydrogels has been extensively used for several applications in food, pharmaceutical, and biomedical fields. The rational design of a functional polymer network is based on the identification of key parameters and mechanisms governing rate and extent of release of the immobilized molecular species. In the present work, a calorimetric study of the water evaporation under non-isothermal conditions is aimed at evaluating functional properties of a series of alginate-based gel beads. The experiments show how a number of variables, such as scan rate, calcium and alginate concentration, operational procedures, and addition of biopolymer co-solutes influence the temperature evolution of the water evaporation from beads. Given the simplicity and the rapidity of the calorimetric experiment, the issue is raised that a scaling approach could be reached by using water as reference material for the prediction of the diffusion kinetics of encapsulated molecules of variable size and properties.     

Shedding light on auxin movement: Light-regulation of polar auxin transport in the photocontrol of plant development

By being sessile, plants have evolved a remarkable capacity to perceive and respond to changes in environmental conditions throughout their life cycle. Light represents probably the most important environmental factor that impinge on plant development because, other than supplying the energy source for photosynthesis, it also provides seasonal and positional information that are essential for the plant survival and fitness. Changes in the light environment can dramatically alter plant morphogenesis, especially during the early phases of plant life, and a compelling amount of evidence indicates that light-mediated changes in auxin homeostasis are central in these processes. Auxin exerts its morphogenetic action through instructive hormone gradients that drive developmental programs of plants. Such gradients are formed and maintained via an accurate control on directional auxin transport. This review summarizes the recent advances in understanding the influence of the light environment on polar auxin transport.