Discretization of the Region of Interest

[EN]The meccano method was recently introduced to construct simultaneously tetrahedral meshes and volumetric parameterizations of solids. The method requires the information of the solid geometry that is defined by its surface, a meccano, i.e., an outline of the solid defined by connected polyhedral pieces, and a tolerance that fixes the desired approximation of the solid surface. The method builds an adaptive tetrahedral mesh of the solid (physical domain) as a deformation of an appropriate tetrahedral mesh of the meccano (parametric domain). The main stages of the procedure involve an admissible mapping between the meccano and the solid boundaries, the nested Kossaczký’s refinement, and our simultaneous untangling and smoothing algorithm. In this chapter, we focus on the application of the method to build tetrahedral meshes over complex terrain, that is interesting for simulation of environmental processes. A digital elevation map of the terrain, the height of the domain, and the required orography approximation are given as input data. In addition, the geometry of buildings or stacks can be considered. In these applications, we have considered a simple cuboid as meccano.Ministerio de Economía y Competitividad, Gobierno de España; Fondos FEDER; Departamento de Educación, Junta de Castilla y León; CONACYT-SENER, Fondo Sectorial CONACYT SENER HIDROCARBUROS

Analysis of the collagen VI assemblies associated with Sorsby's fundus dystrophy.

Age-related macular degeneration is the leading cause of blindness in the Western world, and the pathophysiology of the condition is largely unknown. However, it shares many clinical and pathological features with Sorsby's fundus dystrophy (SFD), an autosomal dominant disease, known to be associated with mutations in the TIMP-3 gene. In Bruch's membrane of both conditions, there are molecular assemblies with distinct transverse bands occurring with a periodicity of about 100 nm. Similar assemblies were also found in the vitreous of a patient with full-thickness macular holes and were identified as being made of collagen VI. The assemblies found in the eye with SFD can be classified into two types, both with a 105-nm axial repeat, but one showing pairs of narrow bands about 30 nm apart and the other showing a single broad band in every repeat. By comparison with the assemblies in the vitreous, collagen VI is considered to be the most likely protein in these assemblies. Furthermore, both of the assemblies associated with SFD can be explained in terms of collagen VI tetramers, one in which the tetramers bind to the mutant tissue inhibitor of metalloproteinases-3 (the gene product of TIMP-3) and the other in which little or no binding occurs. TIMP-3 bound to collagen VI may be more resistant to degradation and create an imbalance between the normal amount of TIMP-3 and matrix metalloproteinases (the substrate of TIMPs) in Bruch's membrane with consequent disruption of the normal metabolic processes. Understanding the structure of these collagen VI/TIMP assemblies in Bruch's membrane may prove to be important for understanding the pathophysiology of age-related macular degeneration