Circular modes of production, known as the circular economy, are welcomed in political and business circles to overcome the shortcomings of traditional linear operating models. Academic literature on the circular economy is nascent however and little attention is given to supply chain management implications, regardless of the relevance of supply chain innovation towards a more resource efficient and circular economy. Based on a review of the literature, this article presents preliminary propositions concerning implications for the development of what we term 'circular supply chains', defined here as the embodiment of circular economy principles within supply chain management. Our propositions are based on the following arguments: a) a shift from product ownership to leasing and access in supply chain relationships; b) the relevance of structural flexibility and start-ups in regional/local loops; c) open and closed material loops in technical and biological cycles; d) closer collaboration within and beyond immediate industry boundaries; and e) public and private procurement in the service industry as a lever for the scaling up of circular business models. We discuss what these circular economy principles mean in terms of supply chain challenges and conclude with limitations and future research agenda.

Novel photochromic dithienylethene-based platinum(II) complexes (C^N^N)Pt(C≡C-DTE-C6H4-D) ((C^N^N) = 4,4'-di(n-hexyl)-6-phenyl-2,2'-bipyridine; D = H, NMe2) were prepared and characterized. Their excellent photochromic properties allow the photoinduced switching of their second-order nonlinear optical properties in solution, as measured by the EFISH technique, due to formation of an extended π-conjugated ligand upon suitable electromagnetic radiation. Insights into the electronic structures of the complexes and the nature of their excited states have been obtained by DFT and TD-DFT calculations. These novel Pt(II) complexes were nanoorganized in polymer films which were poled, affording new materials characterized by a good second-order NLO response that can be easily switched, with an excellent NLO contrast. To the best of our knowledge, our compounds allowed designing the very first examples of switchable NLO polymer films based on metal complexes.

The EU Marine Strategy Framework Directive 2008/56/EC (MSFD) defines a framework for Community actions in the field of marine environmental policy in order to achieve and/or maintain the Good Environmental Status (GES) of the European seas by 2020. Microbial assemblages (from viruses to microbial-sized metazoa) provide a major contribution to global biodiversity and play a crucial role in the functioning of marine ecosystems, but are largely ignored by the MSFD. Prokaryotes are only seen as "microbial pathogens," without defining their role in GES indicators. However, structural or functional prokaryotic variables (abundance, biodiversity and metabolism) can be easily incorporated into several MSFD descriptors (i.e. D1. biodiversity, D4. food webs, D5. eutrophication, D8. contaminants and D9. contaminants in seafood) with beneficial effects. This review provides a critical analysis of the current MSFD descriptors and illustrates the reliability and advantages of the potential incorporation of some prokaryotic variables within the set of indicators of marine environmental quality. Following a cost/benefit analysis against scientific and economic criteria, we conclude that marine microbial components, and particularly prokaryotes, are highly effective for detecting the effects of anthropogenic pressures on marine environments and for assessing changes in the environmental health status. Thus, we recommend the inclusion of these components in future implementations of the MSFD.

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The idea of a circular economy has generated widespread academic, policy and business interest for its potential to address economic, ecological and societal concerns posed by current production and consumption systems. The growth in the number of academic publications reflects a period of critique, clarification and validation leading to research challenges, questions and a call for real world evidence of how the ideas translate into practice, evidence of outcomes and operational effectiveness. Whilst there has been extensive research into the classifications of circular business models, these are rarely linked to a discussion of actual circular value realisation within real world settings. In this paper we draw on three illustrative examples used within a global executive education programme to reflect on the locus of circular value creation and capture. Specifically, we explore the role and interplay of four configurable 'building blocks': circular design, business models, reverse network management and system enablers, as a potentially useful heuristic to describe how businesses are realising value from their circular economy practices. These cases illustrate that the success of large scale value creation and capture derives from the iteration of multiple, boundary spanning activities emerging over time in varying configurations. There is now a need to move from classification and description to quantification and testing of how value is created and captured from circular economy in different contexts. Circular economy validation requires rapid growth in building a credible research evidence base of successful case examples.

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In this work the possibility to exploit the ability of multiple scattering and localization of light shown by diatom silica shells (frustules) for photoluminescence amplification in a random laser was investigated. To this aim polymethylmethacrylate matrix composite random lasers based on rhodamine B and frustules as gain medium and scatterers, respectively, were prepared by solvent casting. Two different kinds of frustules were used, the first represented by diatomite, a fossil material composed of a mixture of frustules from different diatom species, without specific shape, size and porosity; the second were living diatom frustules from freshwater biofilm, a more homogeneous biosilica, dominated by one frustule type. Chemical properties, morphology and photoluminescence of both biosilica fillers were investigated. Random laser experiments were carried out on polymer composites. The diatomite material was characterised by rectangular and circular pores, ranging from 25 nm to 1 μm in size and showed weak photoluminescence upon excitation at 405 nm. Biofilm frustules were more homogeneous in size and microstructure, with average length of about 20 μm and pore diameters between 20 and 100 nm. The frustule photoluminescence, observed after irradiation at 488, 515, 543 and 635 nm was higher than in diatomite. In addition, the two biosilica materials differed with respect to the presence of superficial silanol groups, that were not detected in diatomite. Random laser experiments showed an incoherent random lasing effect in all polymer composites. The laser threshold diminished at increasing frustule content, with a lowest value recorded using biofilm frustules (308 kW cm−2). This is probably due to the frustule size exhibited in this almost monospecific biosilica, that was in the range of most typical morphology-dependent resonators