This book discusses the resilience of communities in both developed and developing world contexts. It investigates the notion of 'resilience' and the challenges faced by local communities around the ...world to deal with disturbances (natural hazards or human-made) that may threaten their long-term survival. Using global examples, specific emphasis is placed on how learning processes, traditions, policies and politics affect the resilience of communities and what constraints and opportunities exist for communities to raise resilience levels.
In a time of great agricultural and rural change, the notion of 'multifunctionality' has remained under-theorized and poorly linked to wider debates in the social sciences. This book analyses the ...extent to which the proposed transition towards post-productivist agriculture holds up to scientific scrutiny, and proposes a modified productivist/non-productivist model that better encapsulates the complexity of agricultural and rural change. By combining existing notions and concepts, this book (re)conceptualizes agricultural change, creating a new transition theory, and a new way of looking at the future of agriculture.
Over the past decade, electrochemical carbon dioxide reduction has become a thriving area of research with the aim of converting electricity to renewable chemicals and fuels. Recent advances through ...catalyst development have significantly improved selectivity and activity. However, drawing potential dependent structure–activity relationships has been complicated, not only due to the ill-defined and intricate morphological and mesoscopic structure of electrocatalysts, but also by immense concentration gradients existing between the electrode surface and bulk solution. In this work, by using in situ surface enhanced infrared absorption spectroscopy (SEIRAS) and computational modeling, we explicitly show that commonly used strong phosphate buffers cannot sustain the interfacial pH during CO2 electroreduction on copper electrodes at relatively low current densities, <10 mA/cm2. The pH near the electrode surface was observed to be as much as 5 pH units higher compared to bulk solution in 0.2 M phosphate buffer at potentials relevant to the formation of hydrocarbons (−1 V vs RHE), even on smooth polycrystalline copper electrodes. Drastically increasing the buffer capacity did not stand out as a viable solution for the problem as the concurrent production of hydrogen increased dramatically, which resulted in a breakdown of the buffer in a narrow potential range. These unforeseen results imply that most of the studies, if not all, on electrochemical CO2 reduction to hydrocarbons in CO2 saturated aqueous solutions were evaluated under mass transport limitations on copper electrodes. We underscore that the large concentration gradients on electrodes with high local current density (e.g., nanostructured) have important implications on the selectivity, activity, and kinetic analysis, and any attempt to draw structure–activity relationships must rule out mass transport effects.
In this work, the effect of Cu nanowire morphology on the selective electrocatalytic reduction of CO2 is presented. Cu nanowire arrays were prepared through a two‐step synthesis of Cu(OH)2 and CuO ...nanowire arrays on Cu foil substrates and a subsequent electrochemical reduction of the CuO nanowire arrays to Cu nanowire arrays. By this simple synthesis method, Cu nanowire array electrodes with different length and density were able to be controllably synthesized. We show that the selectivity for hydrocarbons (ethylene, n‐propanol, ethane, and ethanol) on Cu nanowire array electrodes at a fixed potential can be tuned by systematically altering the Cu nanowire length and density. The nanowire morphology effect is linked to the increased local pH in the Cu nanowire arrays and a reaction scheme detailing the local pH‐induced formation of C2 products is also presented by a preferred CO dimerization pathway.
Catalytic activity: A Cu nanowire array for CO2 reduction was developed. The length and density of the Cu nanowire array could be altered by a simple electroetching method. With varying length and density of the nanowire the chemical selectivity for CO2 reduction could be systematically tuned. The results provide experimental evidence for a nanostructure‐dependent catalytic activity.
The electrocatalytic reduction of CO2 to chemical fuels has attracted significant attention in recent years. Among transition metals, silver shows one of the highest faradaic efficiencies for CO ...formation as the main reaction product; however, the exact mechanism for this conversion is not fully understood. In this work, we study the reaction mechanism of silver as a CO2 reduction catalyst using in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) during electrochemical cycling. Using ATR-FTIR, it is possible to observe the reaction intermediates on the surface of Ag thin films formed during the CO2 electroreduction reaction. At a moderate overpotential, a proton coupled electron transfer reaction mechanism is confirmed to be the dominant CO2 reduction pathway. However, at a more negative applied potential, both the COO– and the COOH intermediates are detected using ATR-FTIR, which indicates that individual proton and electron transfer steps occur, offering a different pathway than at lower potentials. These results indicate that the CO2 reduction reaction mechanism can be potential dependent and not always involving a concerted proton coupled electron transfer, opening alternative pathways to optimize efficient and selective catalysts for desired product formation.
While adult-born neurons in the olfactory bulb (OB) and the dentate gyrus (DG) subregion of the hippocampus have fundamentally different properties, they may have more in common than meets the eye. ...Here, we propose that new granule cells in the OB and DG may function as modulators of principal neurons to influence pattern separation and that adult neurogenesis constitutes an adaptive mechanism to optimally encode contextual or olfactory information. See the related Perspective from Aimone, Deng, and Gage, “Resolving New Memories: A Critical Look at the Dentate Gyrus, Adult Neurogenesis, and Pattern Separation,” in this issue of
Neuron.
The broad-spectrum antiviral drug Arbidol shows efficacy against influenza viruses by targeting the hemagglutinin (HA) fusion machinery. However, the structural basis of the mechanism underlying ...fusion inhibition by Arbidol has remained obscure, thereby hindering its further development as a specific and optimized influenza therapeutic. We determined crystal structures of Arbidol in complex with influenza virus HA from pandemic 1968 H3N2 and recent 2013 H7N9 viruses. Arbidol binds in a hydrophobic cavity in the HA trimer stem at the interface between two protomers. This cavity is distal to the conserved epitope targeted by broadly neutralizing stem antibodies and is ∼16 Å from the fusion peptide. Arbidol primarily makes hydrophobic interactions with the binding site but also induces some conformational rearrangements to form a network of inter- and intraprotomer salt bridges. By functioning as molecular glue, Arbidol stabilizes the prefusion conformation of HA that inhibits the large conformational rearrangements associated with membrane fusion in the low pH of the endosome. This unique binding mode compared with the small-molecule inhibitors of other class I fusion proteins enhances our understanding of how small molecules can function as fusion inhibitors and guides the development of broad-spectrum therapeutics against influenza virus.
Inspired by highly efficient natural motors, synthetic micro/nanomotors are self-propelled machines capable of converting the supplied fuel into mechanical motion. A significant advance has been made ...in the construction of diverse motors over the last decade. These synthetic motor systems, with rapid transporting and efficient cargo towing abilities, are expected to open up new horizons for various applications. Utilizing emergent motor platforms for
in vivo
applications is one important aspect receiving growing interest as conventional therapeutic methodology still remains limited for cancer, heart, or vasculature diseases. In this review we will highlight the recent efforts towards realistic
in vivo
application of various motor systems. With ever booming research enthusiasm in this field and increasing multidisciplinary cooperation, micro/nanomotors with integrated multifunctionality and selectivity are on their way to revolutionize clinical practice.
This review summarizes recent progress in micro/nanomotors towards
in vivo
applications at cell, tissue and biofluid levels.
► Focus on notions of social resilience, adding further to burgeoning debates in this field. ► Innovative focus on both transition theory and various capitals to understand social resilience. ► Novel ...focus on complex interlinkages between globalization processes and social resilience.
This article investigates the impacts of globalization processes on community resilience. It argues that theoretical concepts such as transition theory can provide a lens through which resilience pathways at community level can be better understood, and proposes a framework focused on a social resilience approach for understanding community resilience as the conceptual space at the intersection between economic, social and environmental capital. It argues that certain types of communities are losing resilience through increased embeddedness into globalized pathways of decision-making, while other communities may be gaining resilience, although not one system is either totally resilient or totally vulnerable. Striking the right ‘balance’ between communities and their scalar interactions with the global level is key for maximization of community resilience: while too much isolation of a community may be bad in light of over-dependency on local resources, skills and people, ‘over-globalization’, with possible loss of autonomy and identity, may be equally fraught with problems. In particular, relocalized communities have, so far, not shown much tangible success, as almost all members of the relocalization process at community level are simultaneously embedded within the global capitalist system through their dependencies on global economic processes.
PDF
