An Investigation into the Role of Polymeric Carriers on Crystal Growth within Amorphous Solid Dispersion Systems

Using phase diagrams derived from Flory–Huggins theory, we defined the thermodynamic state of amorphous felodipine within three different polymeric carriers. Variation in the solubility and miscibility of felodipine within different polymeric materials (using F–H theory) has been identified and used to select the most suitable polymeric carriers for the production of amorphous drug–polymer solid dispersions. With this information, amorphous felodipine solid dispersions were manufactured using three different polymeric materials (HPMCAS-HF, Soluplus, and PVPK15) at predefined drug loadings, and the crystal growth rates of felodipine from these solid dispersions were investigated. Crystallization of amorphous felodipine was studied using Raman spectral imaging and polarized light microscopy. Using this data, we examined the correlation among several characteristics of solid dispersions to the crystal growth rate of felodipine. An exponential relationship was found to exist between drug loading and crystal growth rate. Moreover, crystal growth within all selected amorphous drug–polymer solid dispersion systems were viscosity dependent (η–ξ). The exponent, ξ, was estimated to be 1.36 at a temperature of 80 °C. Values of ξ exceeding 1 may indicate strong viscosity dependent crystal growth in the amorphous drug–polymer solid dispersion systems. We argue that the elevated exponent value (ξ > 1) is a result of drug–polymer mixing which leads to a less fragile amorphous drug–polymer solid dispersion system. All systems investigated displayed an upper critical solution temperature, and the solid–liquid boundary was always higher than the spinodal decomposition curve. Furthermore, for PVP–FD amorphous dispersions at drug loadings exceeding 0.6 volume ratio, the mechanism of phase separation within the metastable zone was found to be driven by nucleation and growth rather than liquid–liquid separation.

The Role of Water Content and Paste Proportion on Physico-mechanical Properties of Alkali Activated Fly Ash–Ggbs Concrete

The growth of the construction industry worldwide poses a serious concern on the sustainability of the building material production chain, mainly due to the carbon emissions related to the production of Portland cement. On the other hand, valuable materials from waste streams, particularly from the metallurgical industry, are not used at their full potential. Alkali activated concrete (AAC) has emerged in the last years as a promising alternative to traditional Portland cement based concrete for some applications. However, despite showing remarkable strength and durability potential, its utilisation is not widespread, mainly due to the lack of broadly accepted standards for the selection of suitable mix recipes fulfilling design requirements, in particular workability, setting time and strength. In this paper, a contribution towards the design development of AAC synthetized from pulverised fuel ash (60%) and ground granulated blast furnace slag (40%) activated with a solution of sodium hydroxide and sodium silicate is proposed. Results from a first batch of mixes indicated that water content influences the setting time and that paste content is a key parameter for controlling strength development and workability. The investigation indicated that, for the given raw materials and activator compositions, a minimum water to solid (w/s) ratio of 0.37 was needed for an initial setting time of about 1 hour. Further work with paste content in the range of 30% to 33% determined the relationship between workability and strength development and w/s ratio and paste content. Strengths in the range of 50 - 60 MPa were achieved.

Suitability, efficiency and microbiological safety of novel physical technologies for the processing of ready-to-eat meals, meats and pumpable products

Consumer studies and market reports show an increase in consumption of ready-to-eat (RTE) foods. Although conventional processing technologies can in most cases produce safe products, they can also lead to the degradation of nutritional compounds and negatively affect quality characteristics. Consumers strongly prefer food that is minimally processed with the maximum amount of health-promoting substances. Novel processing technologies as pre- or post-treatment decontamination methods or as substitutes of conventional technologies have the potential to produce foods that are safe, rich in nutrient content and with superior organoleptic properties. Combining novel with conventional processes can eliminate potential drawbacks of novel technologies. This review examines available scientific information and critically evaluates the suitability and efficiency of various novel thermal and nonthermal technologies in terms of microbial safety, quality as well as nutrient content on the production of RTE meals, meats and pumpable products.

Learning to be Boys: Reading the Lessons of Shakespeare’s Love’s Labour’s Lost and Marston’s What You Will

This essay focuses on the lessons of Love’s Labour’s Lost’s pageboy-schoolboy-boy actor, Moth, to examine the production of boyhood in early modern culture. It reads Shakespeare’s boy character alongside John Marston’s schoolboy, Holofernes Pippo, in What You Will to investigate the ways in which school lessons might be deployed to produce aged and gendered identities that complicate traditional understandings of early modern masculinity. Reading the comic staging of lessons in these plays, it will suggest that while the educational system aimed to produce gendered subjects, early modern masculine identities exist as a range of categories on a developmental scale. It will propose that although Moth and Pippo comically expose the limits of many pedagogical methods to produce ‘men’, they demonstrate the ways in which these characters learn to be boys. Finally, it will consider the extent to which this production of early modern age and gender identity in the plays is paralleled by the historical boy actors performing these roles.

The application of a novel fluidised photo reactor under UV-Visible and natural solar irradiation in the photocatalytic generation of hydrogen

With advancements in the development of visible light responsive catalysts for H2 production frequently being reported, photocatalytic water splitting has become an attractive method as a potential ‘solar fuel generator’. The development of novel photo reactors which can enhance the potential of such catalyst, however, is rarely reported. This is particularly important as many reactor configurations are mass transport limited, which in term limits the efficiency of more effective photocatalysts in larger scale applications. This paper describes the performance of a novel fluidised photo reactor for the production of H2 over two catalysts under UV-Visible light and natural solar illumination. Catalysts Pt-C3N4 and NaTaO3.La were dispersed in the reactor and the rate of H2 was determined by GC-TCD analysis of the gas headspace. The unit was an annular reactor constructed from stainless steel 316 and quartz glass with a propeller located in the base to control fluidisation of powder catalysts. Reactor properties such as propeller rotational speed were found to enhance the photo activity of the system through the elimination of mass transport limitations and increasing light penetration. The optimum conditions for H2 evolution were found to be a propeller rotational speed of 1035 rpm and 144 W of UV-Visible irradiation, which produced a rate of 89 µmol h-1 g-1 over Pt-C3N4. Solar irradiation was provided by the George Ellery Hale Solar Telescope, located at the California Institute of Technology.

An Experimental Investigation into the Effects of Flanged Holes in Hat-Stiffened Panels Loaded in Uniaxial Compression

The effects of a 100 mm diameter integrally-flanged hole in a hat-stiffenend carbon-fibre composite panel, loaded in uniaxial compression, were investigated and compared with a similar panel containing an unflanged hole. Details of the manufacturing techniques used in the production of the integral flange are presented. The stiffening effects of the flange reduced the bending strains, which may lead to high interlaminar shear strains, around the cutout while increasing the membrane strains. These membrane strains were well below the limit strains for this composite material. The skin in the unflanged hole also underwent a change in buckling mode shape from three longitudinal half-wavelengths to five half-wavelengths. No such change was observed in the flanged panel and this buckled in four longitudinal half-wavelengths. The ultimate strength of both panels was determined by the load carrying capability of the stiffeners.

The role of LL-37 in periodontal wound healing

Introduction: As a result of chronic inflammation during periodontal disease the junctional epithelium becomes micro-ulcerated. The inflammatory process is mediated by both bacterial and host cell products. Host defence peptides such as defensins, secretory leucocyte protease inhibitor (SLPI) and the sole human cathelicidin, LL-37, are secreted by both periodontal cells and neutrophils into gingival crevicular fluid (GCF). They have the ability to modulate the immune response in periodontitis and are thought to have a potential role in periodontal wound healing. Objectives: The aims of this study were to determine the role of LL-37 in the production of Interleukin (IL)-8, IL-6, hepatocyte growth factor (HGF) and basic-fibroblast growth factor (bFGF) by gingival fibroblasts. The role of LL-37 in modulating total matrix metalloproteinase (MMP) activity and expression of tissue inhibitors of metalloproteinase (TIMP)-1 and -2 by gingival fibroblasts was also investigated. Methods: Primary gingival fibroblasts were co-cultured with concentrations of LL-37 (1, 5 and 10µg/ml) for 24 hours and their supernatants tested for levels of IL-8 and IL-6, HGF, bFGF, TIMP-1 and TIMP-2 by ELISA. Rates of MMP turnover in the supernatants were tested by fluorogenic assay using fluorescence resonance energy transfer (FRET) peptide substrates. Cytotoxicity was measured by MTT assay. Statistical significance was measured using the independent t-test and p<0.05 was considered significant. Results: LL-37 significantly upregulated levels of IL-8, IL-6, HGF, bFGF and TIMP-1 (p<0.05) in a dose-dependent fashion. LL-37 significantly decreased the total MMP activity (p<0.05). None of the LL-37 concentrations tested were cytotoxic to gingival fibroblasts. Conclusion: These results indicate that LL-37 is involved in periodontal wound healing. LL-37 increased levels of proinflammatory cytokines and increased levels of growth factors involved in re-epithelialisation. LL-37 has the ability to regulate remodelling of the periodontium by controlling MMP overactivity both directly and by stimulating production of inhibitors by gingival fibroblasts.