Hierarchical ZSM-5 zeolites were prepared by alkali treatment (desilication) at two temperatures, two reaction times, and two NaOH concentrations. A 23 factorial design was used to study the effect of these variables on the crystallinity, microporosity, and mesoporosity of the zeolite due to the desilication treatment. The factorial design analysis showed that the temperature, reaction time and NaOH concentration and the second order interaction between temperature and time have statistically significant effect on the micropore volume. On mesopore volumes (Vmeso) and areas (Smeso), the reaction time and NaOH concentration factors have statistically significant effects. In the case of mesopore volumes, the second order reaction time and NaOH concentration interaction factor are also significant. On the other hand, only the alkali concentration affected, negatively, the relative crystallinity. Two hierarchical ZSM-5 zeolites with the highest relative crystallinity and mesoporosity were selected and further characterized by inductively coupled plasma (ICP) analysis, 29Si nuclear magnetic resonance (NMR), 27Al NMR, Fourier transform infrared (FTIR) spectroscopy in the OH stretch region and pyridine adsorbed FTIR spectroscopy. NMR and FTIR results showed that the alkali treatment selectively removed silica from the zeolite framework, decreasing the SAR (silica-to-alumina ratio) values, while decreasing Brønsted acid site concentrations and increasing Lewis acid sites concentrations.

Heparan sulphate (HS) and the related polysaccharide, heparin, exhibit conformational and charge arrangement properties, which provide a degree of redundancy allowing several seemingly distinct sequences to exhibit the same activity. This can also be mimicked by other sulphated polysaccharides, both in overall effect and in the details of interactions and structural consequences of interactions with proteins. Together, these provide a source of active compounds suitable for further development as potential drugs. These polysaccharides also possess considerable size, which bestows upon them an additional useful property: the capability of disrupting processes comprising many individual interactions, such as those characterising the attachment of microbial pathogens to host cells. The range of involvement of HS in microbial attachment is reviewed and examples, which include viral, bacterial and parasitic infections and which, in many cases, are now being investigated as potential targets for intervention, are identified.