Novel polymer systems for deep UV microlens arrays

We report for the first time a UV curable polymer with effective optical transmission below 300 nm. Through careful control of kinetics, various viscosities can be generated to optimize the film forming properties via spin coating. The transmission of the monomers and films is investigated over a spectral range which spans the 240-370 nm output of ultraviolet AlInGaN light-emitting diodes. The refractive index of the polymer has been measured by ellipsometry to give a value of 1.57 at 280 nm. Using standard lithography techniques with reactive ion etching, arrays of microlenses have been fabricated in this polymer with diameters of 30μm and below and are characterized by atomic force microscopy and confocal microscopy

Fluorescent nanostructures : direct laser writing of nanosized oligofluorene truxenes in UV-transparent photoresist microstructures

Fluorescent nanostructures within a transparent microstructure can be achieved via direct laser writing. On p. 781, Alexander Kuehne, Peter Skabara, Martin Dawson, Richard Pethrick, and co-workers report on a novel UV-transparent photoresist that incorporates star-shaped nanometer-sized oligofluorene truxenes. The method and materials will find applications in optical, electro-optical, and photonic devices

Influência da urbanização sobre as assembléias de peixes em três córregos de Maringá, Paraná Influence of urbanization upon fish assemblages in three streams of Maringá, Paraná

O objetivo do presente estudo foi avaliar padrões espaciais na composição, estrutura e distribuição das assembléias de peixes e suas relações com características abióticas em três córregos urbanos da cidade de Maringá, Paraná, Brasil. Peixes foram coletados ao longo de um gradiente longitudinal utilizando pesca elétrica nos meses de maio e novembro de 2004. Temperatura, nitrogênio, pH, oxigênio e fósforo foram as variáveis que mais influenciaram a análise de componentes principais (CPA). Riqueza, eqüitabilidade, índice de diversidade de Shannon-Wiener e o primeiro eixo da análise de correspondência com remoção do efeito do arco (DCA) foram diretamente correlacionados com características ligadas ao impacto químico urbano. Adição de espécies prevaleceu nas estações de amostragem do córrego Miosótis e entre a cabeceira e porção intermediária nos córregos Nazaré e Mandacaru. Substituição ocorreu entre as porções intermediárias e foz desses córregos. A dominância da espécie tolerante Poecilia reticulata Peters, 1859 indicou a influência do impacto do meio urbano sobre as assembléias de peixes.<br>The aim of the present study was to evaluate spatial patterns in composition, structure and distribution of fish assemblages and their relationships with abiotic characteristics in three urban streams of Maringá city, Paraná, Brazil. Fish were collected along the longitudinal gradient by electrofishing in May and November 2004. Temperature, nitrogen, pH, oxygen and phosphorous influenced at most the principal components analysis (PCA). Richness, evenness, Shannon-Wiener index and the first axis of detrended correspondence analysis (DCA) were directly correlated with abiotic characteristics related to chemical urban impact. Species addition prevailed in Miosotis stream sampling stations, and between headwater and intermediary reaches in Nazaré and Mandacarú streams. Replacement occurred between intermediary and lowland reaches of these streams. The dominance of the tolerant species Poecilia reticulata Peters, 1859 indicated the influence of the urban impact on fish assemblages