Responsive homes of old Cairo:Learning from the past, feeding in the future

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Responsive homes of old Cairo: Learning from the past, feeding in the future

By investigating the social dynamics of home in one of the enduring communities of Cairo, this paper reveals the way ordinary people construct and consume their private and public domains on a daily basis. It reveals what is central and what is marginal in the cognitive idea of home. This paper adopts an interdisciplinary strategy of investigation, utilizing sociological and anthropological data to read and visit spatial practices in the home. Building on historical as well as contemporary accounts of residents and families, the concept of home is envisioned as a spectrum of social spheres that is liberated from the physical determinants of space, hence revealing a new domain of part-time spaces and dynamic spatiality. The emergent idea of home intertwines work, domesticity, recreation and hospitality in interplay of space-activity-time relationships. Homes of old Cairo have proved to be responsive to continuous change, and have evolved dynamic forms of the temporal settings required for accommodation of emerging home-based professional activities such as hospitality, home-workers, and care-homes.

Phase behavior of mixtures of colloidal platelets and nonadsorbing polymers

The phase behavior of a model system of colloidal platelets and nonadsorbing polymers is studied using computer simulations and perturbation theory. The equation of state for the pure platelet reference system is obtained by Monte Carlo simulations, and the free volume fraction accessible to polymers is measured by a trial insertion method. The free volume fraction is also calculated using scaled particle theory. Subsequently, the phase diagram for platelet-polymer mixtures is calculated. For a platelet aspect ratio L/D=0.1 and a polymer to platelet size ratio d/D>0.2, we observe coexistence between two isotropic phases with different densities. For smaller polymers d/D

Textural, viscoelastic and mucoadhesive properties of pharmaceutical gels composed of cellulose polymers

This study examined the mechanical/textural, viscoeiastic and mucoadhesive properties of a range of aqueous gels composed of either hydroxyethylcellulose (HEC) or sodium carboxymethylcellulose (Na CMC). The mechanical/textural properties of each formulation were determined using texture profile analysis. The viscoelastic properties of each formulation were examined over a defined frequency range (0.01-1.0 Hz) using oscillatory rheometry in conjunction with stainless steel parallel plate geometry. The mucoadhesive properties of the gels were evaluated by measuring the tensile force required to overcome the gel/mucin adhesive interaction. Both gel hardness and compressibility, properties that affect the ease of product removal from a container and spreadability, increased as a function of increasing polymer concentrations. This is attributed to the effects of HEC and Na CMC on gel viscosity. Gel adhesiveness, a property related to bioadhesion, also increased as a function of polymer concentration and is attributed to the reported adhesive nature of these polymers. Increasing frequency of oscillation increased the storage and loss moduli yet decreased bath the dynamic viscosity of each gel type and also the loss tangent of HEC (but not Na CMC) gels. Therefore, following exposure to the range of oscillatory stresses that may be expected in vivo, HEC gels will be more susceptible than Na CMC gels to alterations in these rheological properties. Consequently, it would be expected that the clinical performance of HEC gels will be modified to a greater extent than Na CMC gels. In general, HEC gels exhibited a greater elastic nature than Na CMC gels over the frequency range employed for oscillation The storage and loss moduli and dynamic viscosity of both gel types increased, yet the loss tangent of both gel types decreased as a function of increasing polymer concentration. Gel mucoadhesive strength was dependent on both the time of contact of the formulation with mucin and also on polymer concentration. In conclusion, this study has characterised a number of gels containing either HEC or Na CMC in terms of their mechanical/textural, viscoelastic and mucoadhesive properties. Due to its relevance to the clinical performance, it is suggested that the information derived from these methods may be usefully combined to provide a more rational basis for the selection of polymers and their formulation as topical drug delivery systems. (C) 1997 Elsevier Science B.V.

Sequence analysis of the 3' hypoxia-responsive element of the human erythropoietin gene in patients with erythrocytosis

Erythrocytosis arises from a variety of pathogenic mechanisms. We sequenced a 256-bp region 3' to the erythropoietin (Epo) gene which included a 24- to 50-bp minimal hypoxia-responsive element spanning HIF-1- and HNF-4-binding sites in 12 patients with erythrocytosis and 4 normal subjects. Four polymorphisms were found, none of which affected the HIF-1-binding site, although one polymorphism was present in the HNF-4 consensus region. The data indicate that none of these polymorphisms cause erythrocytosis.