Optimisation of a sol-gel synthesis route for the preparation of MgF2 particles for a large scale coating process.

A synthesis route for the preparation of optically transparent magnesium fluoride sols using magnesium acetate tetrahydrate as precursor is described. The obtained magnesium fluoride sols are stable for several months and can be applied for antireflective coatings on glass substrates. Reaction parameters in the course of sol synthesis are described in detail. Thus, properties of the precursor materials play a crucial role in the formation of the desired magnesium fluoride nanoparticles, this is drying the precursor has to be performed under defined mild conditions, re-solvation of the dried precursor has to be avoided and addition of water to the final sol-system has to be controlled strictly. Important properties of the magnesium fluoride sols like viscosity, particle size distribution, and structural information are presented as well.

Nanoparticles: structure, properties, preparation and behaviour in environmental media.

There is increasing interest and need to develop a deeper understanding of the nature, fate and behaviour of nanoparticles in the environment. This is driven by the increased use of engineered nanoparticles and the increased pressure to commercialise this growing technology. In this review we discuss the key properties of nanoparticles and their preparation and then discuss how these factors can play a role in determining their fate and behaviour in the natural environment. Key focus of the discussion will relate to the surface chemistry of the nanoparticle, which may interact with a range of molecules naturally present in surface waters and sediments. Understanding these factors is a core goal required for understanding the final fate of nanomaterials and predicting which organisms are likely to be exposed to these materials.

Giant hamartoma of the retro- and parapharyngeal region. Case report and review of literature.

Hamartoma designates a tumor-like, non-neoplastic malformation, or in-born error of tissue development, often with an abnormal mixture of tissue indigenous to the region. In the head and neck, epithelial and mesenchymal hamartomas are uncommon. We present the case of a 9-year-old boy with a huge hamartoma of 800ml (cm(3)) volume of the right retro- and parapharyngeal region. It had fully occluded the nasopharynx, indented the base of the tongue and left a minimal airway passage transorally. Food uptake was severely hampered by the lesion. The patient underwent a combined transoral and external approach for complete resection of the tumor. This is the first reported case of a retro- and parapharyngeal hamartoma with metaplastic bone formation in the literature and further more, the largest hamartoma in head and neck ever reported in this age group.