5 resultados para Graft Survival

em WestminsterResearch - UK


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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.

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Sakr challenges the notion that transnational media technologies have forced states in the Arab Middle East to cede ever more control to non-state players since the 1990s. Taking account of a long history of foreign political engineering in Arab countries, she probes the realities of Arab broadcasting privatization, intra-regional harmonization of government communication policies, and external financial support for media freedom and reform, to show how Arab governments were large successfully in harnessing forces implicated in media globalization in a way that entrenched authoritarian elements of the status quo. The findings validate an alternative to globalization theory that places a dual focus on the agency of national ruling elites and the international structures that underpin the power of those elites today, as in the past.

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In the present study, we propose a green route to prepare poly(3-hydroxybutyrate) [(P(3HB)] grafted ethyl cellulose (EC) based green composites with novel characteristics through laccase-assisted grafting. P(3HB) was used as a side chain whereas, EC as a backbone material under an ambient processing conditions. A novel laccase obtained from Aspergillus niger through its heterologous expression in Saccharomyces cerevisiae was used as a green catalyst for grafting purposes without the use of additional initiator and/or cross-linking agents. Subsequently, the resulting P(3HB)-g-EC composites were characterized using a range of analytical and imagining techniques. Fourier transform infrared spectroscopy (FT-IR) spectra showed an increase in the hydrogen-bonding type interactions between the side chains of P(3HB) and backbone material of EC. Evidently, X-ray diffraction (XRD) analysis revealed a decrease in the crystallinity of the P(3HB)-g-EC composites as compared to the pristine individual polymers. A homogeneous P(3HB) distribution was also achieved in case of the graft composite prepared in the presence of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) as a mediator along with laccase as compared to the composite prepared using pure laccase alone. A substantial improvement in the thermal and mechanical characteristics was observed for grafted composites up to the different extent as compared to the pristine counterparts. The hydrophobic/hydrophilic properties of the grafted composites were better than those of the pristine counterparts.

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In the repressive political climate prevailing in Egypt in 2013-15, news ventures aspiring to high standards of reporting were forced to innovate. This paper analyses three Egyptian start-ups that experimented with novel revenue streams and news services during that period, to gain insights into their approaches to managing journalism. In the process it compares different criteria for assessing sustainability and concludes that, in adverse political environments, narrow economic measures of profitability and survival may give a misleading picture as to the sustainability of the kind of journalism conducive to democratic practice. Operating collaboratively, transparently and ethically may slow productivity and profitability in the short term while laying stronger foundations for durable relations among media teams, as well as with readers and advertisers, in the long run.