Canine rhinitis caused by an uncommonly-diagnosed fungus, Scedosporium apiospermum.

A Golden Retriever cross was presented with a four week history of violent sneezing and licking at the nasal planum. Nasal mycosis was diagnosed and Aspergillus sp. presumed the causative agent, until culture, PCR and DNA sequencing showed that Scedosporium apiospermum, an uncommonly diagnosed, yet emerging, fungal pathogen, was the agent responsible. Debridement of the fungal plaques and systemic itraconazole therapy resulted in complete resolution of clinical disease. We discuss the current literature on S. apiospermum, review its clinical significance and question the validity of its 'complex' taxonomy.

Mesostructure of Ordered Corneal Nano-nipple Arrays: The Role of 5-7 Coordination Defects.

Corneal nano-nipple structures consisting of hexagonally arranged protrusions with diameters around 200 nm have long been known for their antireflection capability and have served as biological blueprint for solar cell, optical lens and other surface designs. However, little is known about the global arrangement of these nipples on the ommatidial surface and their growth during the eye development. This study provides new insights based on the analysis of nano-nipple arrangements on the mesoscale across entire ommatidia, which has never been done before. The most important feature in the nipple structures are topological 5- and 7-fold coordination defects, which align to form dislocations and interconnected networks of grain boundaries that divide the ommatidia into crystalline domains in different orientations. Furthermore, the domain size distribution might be log-normal, and the domains demonstrate no preference in crystal orientation. Both observations suggest that the nipple growth process may be similar to the nucleation and growth mechanisms during the formation of other crystal structures. Our results are also consistent with the most recently proposed Turing-type reaction-diffusion process. In fact, we were able to produce the key structural characteristics of the nipple arrangements using Turing analysis from the nucleation to the final structure development.

Remarkable crystal and defect structures in butterfly eye nano-nipple arrays.

The corneal nipple structures on the eyes of two nymphalid butterfly species (Nymphalis antiopa and Polygonia interrogationis) are analyzed in terms of nipple arrangements and associated defects. The nipple arrays in both species have close-packed hexagonal lattices with lattice parameters of about 200 nm. The most abundant defects observed are 5-7 coordination defects that generate dislocations, dislocation-type low angle and structural unit-like high angle grain boundaries, as well as closed-loop defects. These disordered structures are compared with imperfections found in other 2D and 3D crystal structures, and it is concluded that the defects in the nipple arrays are likely not due to random growth accidents. Instead, they could be the result of geometric constraints due to eye curvature or serve a yet undiscovered purpose in the optical properties of these eyes.

Grain boundaries and coincidence site lattices in the corneal nanonipple structure of the Mourning Cloak butterfly.

In this study the highly ordered corneal nanonipple structure observed on the Mourning Cloak butterfly (Nymphalis antiopa) is analyzed with a particular emphasis on the high-angle grain-boundary-like defects that are observed between individual nanonipple crystals. It is shown that these grain boundaries are generated by rows of topological coordination defects, which create very specific misorientations between adjacent crystals. These specific orientations form coincidence site lattices, which (i) have unit cells larger than the unit cell in each individual crystal and (ii) extend from one crystal to the next, effectively creating order over areas larger than the individual crystals. A comparison to similar coincidence site lattices in engineering materials is made and the importance of such arrangements in terms of nipple packing density, corneal lens curvature and potential optical properties is discussed.