Present status of Medical Physics practice in Mexico: An occupational analysis.

Purpose: To present an overview of the status of Medical Physics practice in Mexico, promote the legal recognition of Medical Physics high-end training, and provide information that will potentially improve the Mexican healthcare system.

Methods: For the purpose of this research, the concept of "Medical Physics Professional/s" (MPP) is introduced to refer to any person/s executing the role of a clinical medical physicist (cMP) in whole or in part independent of academic profile, training or experience. A database of MPP in Mexico was built from official sources and personal communication with peers.

The nucleation kinetics of ZnO nanoparticles from ZnCl2 in ethanol solutions.

The first stages of the synthesis of ZnO nanoparticles by forced hydrolysis of ZnCl2 with NaOH and water in ethanol have been investigated using UV-Vis spectrophotometry. At sufficiently low water concentrations, focusing of the nanoparticle size distribution was observed during the nucleation and growth phase, followed by a defocusing phase when coarsening becomes significant. During nucleation and growth, only the smaller particles grow while the larger particles have an essentially zero growth rate, indicating that the growth rate decreases rapidly with particle size.