Biologically enabled sub-diffractive focusing.

Evolution shows that photonic structures are a constituent part of many animals and flora. These elements produce structural color and are useful in predator-prey interactions between animals and in the exploitation of light for photosynthetic organisms. In particular, diatoms have evolved patterned hydrated silica external valves able to confine light with extraordinary efficiency. Their evolution was probably guided by the necessity to survive in harsh conditions of sunlight deprivation. Here, we exploit such diatom valves, in conjunction with structured illumination, to realize a biological super-resolving lens to achieve sub-diffractive focusing in the far field. More precisely, we consider a single diatom valve of Arachnoidiscus genus which shows symmetries and fine features. By characterizing and using the transmission properties of this valve using the optical eigenmode technique, we are able to confine light to a tiny spot with unprecedented precision in terms of resolution limit ratio, corresponding in this case to 0.21λ/NA.

[Giant multifocal venous malformation with monomelic predominance]. / Malformation veineuse multifocale majeure à prédominance monomélique.

INTRODUCTION: Venous malformations are usually easy to recognise. We describe one case in which the clinical aspect was suggestive of Maffucci's syndrome. OBSERVATION: A 44-year-old male, had numerous angiomatous nodules which could be emptied by pressure since infancy. The progressive increase in volume of these lesions on the arms and forearms led to enormous deformation and major disability. The thoracic area and the right foot were also affected to a lesser degree. Two endobuccal lesions were also found on the clinical examination The cutaneous lesions were tender and occasionally hyperhidrosis was present. The presence of phleboliths on Xray and the presence of venous and capillary cavities with numerous thrombi confirmed the diagnosis of venous malformation. Following the failure of the Ethibloc(R) embolization, eight excisions were made in a two-year-period with a good functional result. Elastic strapping was then applied. DISCUSSION: The diagnosis of venous malformation was based on clinical, radiological and histological findings. The absence of chondroma excluded the diagnosis of Maffucci's syndrome. Spindle cell hemangioendothelioma, "blue rubber bleb nevus" and glomangiomatosis were confirmed by the histological findings. The absence of port-wine stain or bone hypertrophy and the presence of multiple nodules excluded Klippel-Trenaunay syndrome. The presence of multifocal involvement with oral lesions, the severity of the deformation and the relative success of the surgical procedure make this case unusual.

[Evaluation of the Coulter T-660 hematologic analyzer compared with the Hemalog 8/90]. / Valutazione dell'analizzatore ematologico Coulter T-660: confronto con l'Hemalog 8/90.

The authors evaluated technical performance of two automated haematological counters, the Coulter T-660 in comparison to Hemalog 8/90. Both systems showed a good correlation and a good precision. The Coulter T-660 revealed to be a high standard analyzer, that can adequately support more complex haematological analyzers in laboratory routine.