Paradigm Flaw in the Boardroom: Governance versus Management

The purpose of this paper is to explore a more constructive role for corporate boards — one that would entail directors recognising the operational primacy of management and focusing their attention on the manner in which a corporation can best fulfil its long-term strategy. Paying more attention to nurturing long-term, sustainable value will help differentiate roles and will suggest the need for new metrics and a deeper appreciation by directors of corporate strategy and organisational capacity. At a time when senior management are dedicating disproportionate resources to immediate compliance issues, it is critical that boards take such a broad view

Stress transfer quantification in gelatin-matrix natural composites with tunable optical properties

© 2015 American Chemical Society.This work reports on the preparation and characterization of natural composite materials prepared from bacterial cellulose (BC) incorporated into a gelatin matrix. Composite morphology was studied using scanning electron microscopy and 2D Raman imaging revealing an inhomogeneous dispersion of BC within the gelatin matrix. The composite materials showed controllable degrees of transparency to visible light and opacity to UV light depending on BC weight fraction. By adding a 10 wt % fraction of BC in gelatin, visible (= 550 nm) and UV (= 350 nm) transmittances were found to decrease by ∼35 and 40%, respectively. Additionally, stress transfer occurring between the gelatin and BC fibrils was quantified using Raman spectroscopy. This is the first report for a gelatin-matrix composite containing cellulose. As a function of strain, two distinct domains, both showing linear relationships, were observed for which an average initial shift rate with respect to strain of -0.63 ± 0.2 cm-1%-1 was observed, followed by an average shift rate of -0.25 ± 0.03 cm-1%-1. The average initial Raman band shift rate value corresponds to an average effective Youngs modulus of 39 ± 13 GPa and 73 ± 25 GPa, respectively, for either a 2D and 3D network of BC fibrils embedded in the gelatin matrix. As a function of stress, a linear relationship was observed with a Raman band shift rate of -27 ± 3 cm-1GPa-1. The potential use of these composite materials as a UV blocking food coating is discussed

A structural study of the self-association of different starches in presence of bacterial cellulose fibrils

A multi-analytical study was performed to analyse the effect of bacterial cellulose (BCF) on the self-association of starches with different amylose content (wheat, waxy-maize), assessing macrostructural properties (rheology, gel strength) and some nano and sub-nano level features (small and wide-angle X-ray scattering). Although pasting viscosities and G′ were significantly increased by BCF in both starches, cellulose did not seem to promote the self-association of amylose in short-range retrogradation. A less elastic structure was reflected by a 2–3-fold increase in loss factor (G″/G′) at the highest BCF concentration tested. This behavior agreed with the nano and sub-nano characterisation of the samples, which showed loss of starch lamellarity and incomplete full recovery of an ordered structure after storage at 4 °C for 24 h. The gel strength data could be explained by the contribution of BCF to the mechanical response of the sample. The information gained in this work is relevant for tuning the structure of tailored starch-cellulose composites

Influence of extraction variables on the structure and physical properties of salmon gelatin

This work focuses on investigating the effect of extraction conditions (pH and time) on the biochemical and physical properties of salmon gelatin (SG). SG was extracted from salmon skins under different pH and time conditions at 60 degrees C. The characterization of the material considered proximate composition, amino acid profile, molecular weight (MW), gel strength, X-Ray diffraction, thermal properties, dynamic mechanical properties and dynamic vapour sorption analysis. Results showed that higher protein content was obtained with extraction condition pH5/2h, while lower protein content was obtained at condition pH3/5h. Extraction performed at pH5 produced SG with MW > 120 kDa, while processing condition at pH3 resulted in MW bands distributed between 20 and 100 kDa. Higher contents of proline and hydroxyproline were detected in SG with high MW. This behaviour was directly correlated with gel strength and thermo-mechanical properties: higher gel strength and E' modulus were observed in SG with high MW, suggesting higher amount of triple helical structures in gelatin matrix. This was also supported by higher values of tans detected as the MW of SG decreased. This may be related with decreasing the crystalline fraction of SG. Thermal properties revealed no significant differences in melting temperature and glass transition temperature values among samples. The melting energy was significantly lower for SG with lower MW. This was confirmed by X-Ray diffraction where the intensity of the diffraction peak at similar to 2 theta = 8 degrees significantly decreased for SG extracted under more aggressive conditions. Finally, gelatin extracted under mild conditions showed higher moisture content, which was in agreement with higher amounts of triple-helix structures. Our results suggest the possibility to modulate the physical properties of SG by tuning the extraction process to obtain tailored gelatin structures for high-value applications in food technology, tissue engineering and biomedicine.FONDECYT, 1140132 / Postdoc Grant FAI UANDES, FCH-PD-2015-