Laccase-assisted bio-grafting of polyhydroxy-alkanoates (PHAs) onto the ethyl cellulose (EC) backbone

In the present study, a novel enzyme-based methodology for grafting Polyhydroxyalkanoates (PHAs) onto the ethyl cellulose (EC) as a backbone polymer was developed. Laccase assisted copolymerization was carried out under mild and eco-friendly reaction conditions. The resulting homogeneous composite membranes were characterized by Fourier-transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Atomic Force Microscopy (AFM). The FTIR spectra of pure PHAs and PHAs containing graft composites (PHAs-g-EC) showed their strong characteristic bands at 1721 cm1, 1651 cm-1 and 1603 cm-1 respectively. Other accompanying bands in the range of 900-1300 cm-1 correspond to C=O vibration and C-O-C bond stretching, which could be contributed from PHAs and EC, respectively. The high intensity of the 3358 cm-1 band in the graft composite may have corresponded to the degradation of the carboxylic group from PHAs and also showed an increase of hydrogen-bonded groups at that distinct band region. The morphology was examined by SEM, which showed the well dispersed PHAs crystals in the backbone polymer of EC. XRD pattern for PHAs showed distinct peaks at 2-Theta values of 28o, 32o, 34o, 39o, 46o, 57o, 64o, 78o and 84o that represent the crystalline nature of PHAs. In comparison with those of neat PHAs, the degree of crystallinity for PHAs-g-EC decreased and this reduction is mainly because of the new cross-linking of PHAs within the EC backbone that changes the morphology and destroys the crystallites. Improved mechanical properties were observed for the PHAs-g-EC as compared to the individual components due to the impregnation of EC as reinforcement into the PHAs matrix. Improved mechanical strength enhanced thermal properties, along with low crystallinity of the present PHAs-g-EC suggesting its potential for various industrial and bio-medical applications.

Laccase-assisted approach to graft multifunctional materials of interest: keratin-EC based novel composites and their characterisation

This study focuses on the evaluation of raw keratin as a potential material to develop composites with novel characteristics. Herein, we report a mild and eco-friendly fabrication of in-house extracted feather keratin-based novel enzyme assisted composites consisting of ethyl cellulose (EC) as a backbone material. A range of composites between keratin and EC using different keratin: EC ratios were prepared and characterised. Comparing keratin to the composites, the FT-IR peak at 1,630 cm-1 shifted to a lower wavenumber of 1,610 cm-1 in keratin-EC which typically indicates the involvement of β-sheet structures of the keratin during the graft formation process. SEM analysis revealed that the uniform dispersion of the keratin increases the area of keratin-EC contact which further contributes to the efficient functionality of the resulting composites. In comparison to the pristine keratin and EC, a clear shift in the XRD peaks was also observed at the specific region of 2-Theta values of keratin-g-EC. The thermo- mechanical properties of the composites reached their highest levels in comparison to the keratin which was too fragile to be measured for its mechanical properties. Considerable improvement in the water contact angle and surface tension properties was also recorded.

Development of user-friendly, high throughput screening for ligands and inhibitors of carbohydrate modifying enzymes

This paper describes the impact of cloud computing and the use of GPUs on the performance of Autodock and Gromacs respectively. Cloud computing was applicable to reducing the ‘‘tail’’ seen in running Autodock on desktop grids and the GPU version of Gromacs showed significant improvement over the CPU version. A large (200,000 compounds) library of small molecules, seven sialic acid analogues of the putative substrate and 8000 sugar molecules were converted into pdbqt format and used to interrogate the Trichomonas vaginalis neuraminidase using Autodock Vina. Good binding energy was noted for some of the small molecules (~-9 kcal/mol), but the sugars bound with affinity of less than -7.6 kcal/mol. The screening of the sugar library resulted in a ‘‘top hit’’ with a-2,3-sialyllacto-N-fucopentaose III, a derivative of the sialyl Lewisx structure and a known substrate of the enzyme. Indeed in the top 100 hits 8 were related to this structure. A comparison of Autodock Vina and Autodock 4.2 was made for the high affinity small molecules and in some cases the results were superimposable whereas in others, the match was less good. The validation of this work will require extensive ‘‘wet lab’’ work to determine the utility of the workflow in the prediction of potential enzyme inhibitors.

Eco city development in China: addressing the policy implementation challenge

Over the last few decades, China has seen a steep rise in diverse eco city and low carbon city policies. Recently, attention has begun to focus on the perceived shortcomings in the practical delivery of related initiatives, with several publications suggesting a gap between ambitious policy goals and the emerging realities of the newly built environment. To probe this further, in this article we examine – based on the policy network approach – how the gap between high-level national policies and local practice implementation can be explained in the current Chinese context. We develop a four-pronged typology of eco city projects based on differential involvement of key (policy) actor groups, followed by a mapping of what are salient policy network relations among these actors in each type. Our analysis suggests that, within the overall framework of national policy, a core axis in the network relations is that between local government and land developers. In some cases, central government agencies– often with buy-in from international architecture, engineering and consulting firms – seek to influence local government planning through various incentives aimed at rendering sustainability a serious consideration. However, this is mostly done in a top-down manner, which overemphasizes a rational, technocratic planning mode while underemphasizing interrelationships among actors. This makes the emergence of a substantial implementation gap in eco city practice an almost predictable outcome. Consequently, we argue that special attention be paid in particular to the close interdependency between the interests of local government actors and those of land and real estate developers. Factoring in this aspect of the policy network is essential if eco city implementation is to gain proper traction on the ground.

Eco-cities: technological showcases or public spaces?

A growing body of critical literature seeks to identify conceptual and practical problems accompanying the realisation of mainstream ‘eco-city’ initiatives around the world. However, little attention has been paid to the status of the ‘city’ itself within the broader discourse. If eco-cities are to be more than experimental ‘technological showcases’, and aim to transform urban life more generally, the question of what types of ‘cityness’ will ensue is of considerable importance. To effect a more significant sustainability transition, eco-city plans and policies may need somehow to encompass a more nuanced conceptualisation of cities as complex, unpredictable, and emergent spaces. The incompatibility of such a conceptualisation with liberal-modernist modes of planning means that radically innovative new approaches to eco-city development may need to be found. This thesis considers whether the eco-city, theorised as a multiple process of real-world experimentation, may shed some light on how ‘cityness’ might better be planned for in future. To do so, it conceptualises cityness through the lens of ‘publicness’. It makes an original contribution to knowledge by developing a new theoretical model of publicness as an ‘assemblage’ of space and behaviour, with an ‘emergent’ and ‘civic’ modality. It thereby extends recent debates over the idea of ‘urban assemblage’, and makes innovative links between theories of planning and of the public. This model informs the analysis of original empirical research, investigating the conceptualisation of the public in an international sample of official eco-city documents, and exploring the publicness of two implemented initiatives, in Portland, Oregon (US) and newly built Sejong City (South Korea). The research finds that publicness tends to be poorly articulated in mainstream eco-city plans and policies, with potentially negative implications for sustainability in the ‘urban age’. However, it also argues that state institution-led planning – even when experimental ‘governance’ approaches are adopted – may inevitably be limited in its ability to encompass the emergent public life of the city. The thesis concludes by considering the prospects for overcoming or more productively acknowledging these limits in future.