Natural waste materials containing chitin as adsorbents for textile dyestuffs: batch and continuous studies.

In this work three natural waste materials containing chitin were used as adsorbents for textile dyestuffs, namely the Anodonta (Anodonta cygnea) shell, the Sepia (Sepia officinalis) and the Squid (Loligo vulgaris) pens. The selected dyestuffs were the Cibacron green T3G-E (CI reactive green 12), and the Solophenyl green BLE 155% (CI direct green 26), both from CIBA, commonly used in cellulosic fibres dyeing, the most used fibres in the textile industry. Batch equilibrium studies showed that the materials' adsorption capacities increase after a simple and inexpensive chemical treatment, which increases their porosity and chitin relative content. Kinetic studies suggested the existence of a high internal resistance in both systems. Fixed bed column experiments performed showed an improvement in adsorbents' behaviour after chemical treatment. However, in the column experiments, the biodegradation was the main mechanism of dyestuff removal, allowing the materials' bioregeneration. The adsorption was strongly reduced by the pore clogging effect of the biomass. The deproteinised Squid pen (grain size 0.500-1.41 mm) is the adsorbent with highest adsorption capacity (0.27 and 0.037 g/g, respectively, for the reactive and direct dyestuffs, at 20 degrees C), followed by the demineralised Sepia pen and Anodonta shell, behaving like pure chitin in all experiments, but showing inferior performances than the granular activated carbon tested in the column experiments.

Reconstrução anatômica das artérias coronárias nativas e das pontes de safena utilizando Less Shortening Wallstent / Anatomic reconstruction of native coronary arteries and vein graft with the Less Shortening SelfÄExpandable Wallstent

OBJETIVO Ä Avaliar a utilizaçäo de apenas um stent, owallstent (WS), no tratamento de lesöes longas (LL) ou múltiplas (LM). MÉTODOS Ä Trinta e oito pacientes com idades variando de 42Ä82 (m=66) anos, sendo por cento do sexo masculino. Os vasos tratados foram: descendente anterior (14 pacientes); coronária direita (12); circunflexa (9) e pontes de safena (4). Cinco pacientes necessitaram de 2 stents: 4 PalmazÄSchatz no segmento proximal do vaso e um que recebeu dois WS com diâmetro maior ou igual a 1,5mm do diâmetro nominal do vaso.Todos os pacientes necessitaram de hiperinsuflação após o implante do WS. RESULTADOS - O sucesso do implante foi de 95 por cento. Os dois casos de insucesso foram: um devido à fratura do sistema e outro à soltura incompleta. Ambos, submetidos à angioplastia convencional com sucesso. Não houve complicaçöes nesta série. CONCLUSÄO - O WS foi efetivo no tratamento de LL e LM com alto índice de sucesso imediato e sem complicaçöes.