Propriedades mesomórficas de tensioactivos cataniónicos

Dissertação apresentada à Universidade de Coimbra para cumprimento dos requisitos necessário à obtenção de grau de Mestre em Química, na especialidade de Química FísicaNeste trabalho foram preparados vários compostos de uma nova classe de moléculas anfifílicas, os tensioactivos cataniónicos, resultantes da formação de um par tensioactivo aniónico-catiónico com remoção dos respectivos contra-iões. Após a síntese dos compostos, foi efectuado um estudo do seu comportamento de fase térmico (termotrópico) e em meio aquoso (liotrópico). Os tensioactivos preparados diferem quanto ao número total de caudas (2 ou 3 caudas), quanto ao número de carbonos nas caudas (de 8 até 18) e quanto à natureza química das cabeças hidrofílicas (amónio, sulfato e carboxilato). Dada a diversidade dos compostos preparados, pretendeu-se esclarecer a influência da geometria e natureza química dos compostos no comportamento de fase desta classe de tensioactivos. A caracterização da fase sólida e a análise dos comportamentos termotrópicos e liotrópicos dos compostos foram realizadas com base nas técnicas de: microanálise elemental, absorção atómica, condutividade, microscopia óptica com luz polarizada, análise térmica diferencial (DTA), calorimetria diferencial de varrimento (DSC), difracção de raios-X de pequeno ângulo (SAXS), penetração de fase com varrimento e microscopia de transmissão electrónica com criogenia (Cryo-TEM). Com base nos resultados experimentais pretende-se fazer um estudo de descrição e racionalização das propriedades dos tensioactivos cataniónicos, nomeadamente o estudo do efeito da assimetria estrutural das moléculas na natureza e sequência de mesofases formadas

Dewatering of Anaerobic Digested Sludge with Oil Palm Biomass as Novel Physical Conditioner

This study investigated the use of oil palm biomass, namely empty fruit bunch (EFB), palm kernel shell (PKS), and the biomass residue, palm ash (PA), as physical conditioner, to improve the dewaterability of anaerobic digested sludge. The dewatering performance of the conditioned sludge in this work was evaluated with four common measurements i.e. the capillary suction time (CST), specific resistance to filtration (SRF), net sludge solids yield (YN), and moisture content of the sludge cake. Amongst all the biomass samples, the ground EFB passing through a 0.6-mm mesh sieve indicated the highest reduction in SRF and the highest gain in YN at solids mass ratio of conditioner to sludge of 1.6. When the conditioned sludge was subjected to filtration dewatering, the presence of oil palm biomass in sludge may act as a skeleton builder to provide a porous, permeable and rigid lattice sludge cake structure which allows the passage of water and consequently enhances water removal from sludge

Sociodemographic and clinical factors for non-hospital deaths among cancer patients: A nationwide population-based cohort study

10.1371/journal.pone.0232219PLoS ONE154e023221

Cancer patients as frequent attenders in emergency departments: A national cohort study

10.1002/cam4.1728Cancer Medicine794434-444

Quality assessment of a formulated Chinese herbal decoction, Kaixinsan, by using rapid resolution liquid chromatography coupled with mass spectrometry: A chemical evaluation of different historical formulae

Kaixinsan is an ancient Chinese herbal decoction mainly prescribed for patients suffering from mental depression. This decoction was created by Sun Si-miao of Tang Dynasty (A.D. 600) in ancient China, and was composed of four herbs: Radix and Rhizome Ginseng, Radix Polygalae, Rhizoma Acori Tatarinowii and Poria. Historically, this decoction has three different formulations, each recorded at a different point in time. In this study, the chemical compositions of all three Kaixinsan formulae were analyzed. By using rapid resolution LC coupled with a diode-array detector and an ESI triple quadrupole tandem MS (QQQ-MS/MS), the Radix and Rhizome Ginseng-derived ginsenosides including Rb₁, Rd, Re, Rg₁, the Radix Polygalae-derived 3,6′-disinapoyl sucrose, the Rhizoma Acori Tatarinowii-derived α- and β-asarone and the Poria-derived pachymic acid were compared among the three different formulations. The results showed variations in the solubility of different chemicals between one formula and the others. This systematic method developed could be used for the quality assessment of this herbal decoction. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim