127 research outputs found

    Alaska Natives and American Laws

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    In this thesis we focus on the issue of crowdfunding and especially how a project relates to and embraces its community. While a lot of related research focus on what makes people give, our research instead delve into whether a creator looks upon the sponsors as something more than just a financial resource. To manage this task we used a triangular perspective consisting of a case study, a questionnaire and a netnographic study. The goal was to gain the perspectives of creators, crowdfunding platforms and sponsors on how the communication between the community and the project works and can be improved.        The three crowdfunding platforms we reviewed (Kickstarter, IndieGoGo, Rockethub) all had fairly similar models on how to attract sponsors and make them involved in the project, while the questionnaire and netnographic study demonstrated how a community could contribute in different ways. Based on our results we draw the conclusion that a project can be successful without embracing the creative qualities of its sponsors but doing so also is a waste of a great asset to both current and future projects.

    Electrochemical reduction of allyl halides in nonaqueous solvents - a reinvestigation

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    Abstract: The electrochemical reduction of allyl iodide (la), allyl bromide (lb), (E)-3-bromo-l-phenyl-l-propene (IC), and (E)-5-bromo-2,2,6,6-tetramethyl-3-heptene (Id) was studied in dry acetonitrile with TBAP as supporting electrolyte by means of cyclic voltammetry and coulometry at mercury, platinum, and vitreous carbon electrodes. Compounds la-c showed multiple waves on platinum and mercury because of halide surface effects. However on vitreous carbon la-d gave single reduction waves, with half-peak potentials of -1.38, -1.64, -1.1 I , and -1.89 V (vs. SCE), respectively. Apparent coulometric n values of 1 for la-c were shown to arise from rapid nucleophilic substitution of the allyl anion intermediates with starting halide to give electroinactive dimers. Sterically hindered Id showed an napp of 2 and did not exhibit surface interactions with Hg and Pt. Thus allyl halides, contrary to previous statements in the literature, are reduced via a two-electron electrode reaction and the reduction of the allyl radical to the allyl anion cannot be seen as a separate step. Evidence was also obtained for the formation of the allyl anion by reduction of l a and I b with solvated electrons in liquid ammonia; the electrochemical oxidation of this species in this medium occurred at ca. -1.2 V. Introduction The electrochemical reduction of organic halogen compounds has been widely investigated and several reviews are available.* As was first shown by von Stackelberg and S t r a~k e ,~ the overall reaction involves cleavage of the carbon-halogen bond in a single two-electron polarographic wave to give a carbanion which is subsequently protonated (Schem

    Electrochemistry, Spectroscopy and Electrogenerated Chemiluminescence of Perylene, Terrylene, and Quaterrylene Diimides in Aprotic Solution

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    The electrochemistry, UV-vis spectrophotometry, photoluminescence, and electrogenerated chemiluminescence (ECL) of perylenedicarboxylic imide, perylenetetracarboxylic diimide (PDI), terrylenetetracarboxylic diimide (TDI), and quaterrylenecarboxylic diimide (QDI) were investigated. All compounds undergo two reversible one-electron reductions and one reversible one-electron oxidation reaction. The first reduction potential shifts to less negative values and the potential for oxidation to less positive values for the diimide series with increasing size of the aromatic core. These changes in potential correlate well with orbital energies from molecular orbital calculations. The difference in potential between the first and second reduction waves decreased with increasing distance between the imide groups, so that TDI and QDI show only a single reduction wave, equivalent to a two-electron reduction. These reduction potentials provide estimates for the equilibrium constant for disproportionation of the radical anion. Very stable ECL spectra of PDI or TDI generated by sequential production of the radical cation and radical anion at an electrode were observed; these were identical to the photoluminescence spectra. A consideration of the energetics of the electron transfer reaction and the singlet energy leads to the conclusion that emission occurs mainly via generation of triplets followed by triplet-triplet annihilation (the T-route)

    A Precious-Metal-Free Hybrid Electrolyzer for Alcohol Oxidation Coupled to CO2 -to-Syngas Conversion.

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    Electrolyzers combining CO2 reduction (CO2 R) with organic substrate oxidation can produce fuel and chemical feedstocks with a relatively low energy requirement when compared to systems that source electrons from water oxidation. Here, we report an anodic hybrid assembly based on a (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) electrocatalyst modified with a silatrane-anchor (STEMPO), which is covalently immobilized on a mesoporous indium tin oxide (mesoITO) scaffold for efficient alcohol oxidation (AlcOx). This molecular anode was subsequently combined with a cathode consisting of a polymeric cobalt phthalocyanine on carbon nanotubes to construct a hybrid, precious-metal-free coupled AlcOx-CO2 R electrolyzer. After three-hour electrolysis, glycerol is selectively oxidized to glyceraldehyde with a turnover number (TON) of ≈1000 and Faradaic efficiency (FE) of 83 %. The cathode generated a stoichiometric amount of syngas with a CO:H2 ratio of 1.25±0.25 and an overall cobalt-based TON of 894 with a FE of 82 %. This prototype device inspires the design and implementation of nonconventional strategies for coupling CO2 R to less energy demanding, and value-added, oxidative chemistry

    Nitric oxide sensing in plants is mediated by proteolytic control of group VII ERF transcription factors

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    Nitric oxide (NO) is an important signaling compound in prokaryotes and eukaryotes. In plants, NO regulates critical developmental transitions and stress responses. Here, we identify a mechanism for NO sensing that coordinates responses throughout development based on targeted degradation of plant-specific transcriptional regulators, the group VII ethylene response factors (ERFs). We show that the N-end rule pathway of targeted proteolysis targets these proteins for destruction in the presence of NO, and we establish them as critical regulators of diverse NO-regulated processes, including seed germination, stomatal closure, and hypocotyl elongation. Furthermore, we define the molecular mechanism for NO control of germination and crosstalk with abscisic acid (ABA) signaling through ERF-regulated expression of ABSCISIC ACID INSENSITIVE5 (ABI5). Our work demonstrates how NO sensing is integrated across multiple physiological processes by direct modulation of transcription factor stability and identifies group VII ERFs as central hubs for the perception of gaseous signals in plants

    Fixation and Permeabilization Approaches for Scanning Electrochemical Microscopy of Living Cells

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    Scanning electrochemical microscopy (SECM) has been widely used for the electrochemical imaging of dynamic topographical and metabolic changes in alive adherent mammalian cells. However, extracting intracellular information by SECM is challenging, since it requires redox species to travel in and out the lipid cell membrane. Herein, we present cell fixation and permeabilization approaches as an alternative tool for visualizing cell properties by SECM. With this aim, adherent cells were analyzed in the SECM feedback mode in three different conditions: i) alive; ii) fixed and iii) fixed and permeabilized. The fixation was carried out with formaldehyde and does not damage lipid membranes. Therefore, this strategy can be used for the SECM investigation of cell topography or the passive transport of the redox mediator into the cells. Additional permeabilization of the cell membrane after fixation enables the analysis of the intracellular content through the coupling of SECM with immunoassay strategies for the detection of specific biomarkers. The latter was successfully applied as an easy and fast screening approach to detect the expression of the melanoma associated marker tyrosinase in adherent melanoma cell lines corresponding to different cancer progression stages using the SECM substrate generation – tip collection mode. The present approach is simple, fast and reliable and can open new ways to analyze cell cultures with electrochemically based scanning probe techniques

    Capacitive and non-capacitive faradaic charge storage

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    This article aims to offer a critical overview of selected literature on capacitive and non-capacitive faradaic charge storage. It is particularly relevant to the concept of pseudocapacitance that is generally described as a result of fast surface faradaic processes. In general, faradaic processes represent electron transfer reactions at the interface between an electrode and its contacting solid or liquid electrolyte phase that is able to accept or donate electrons. Obviously, not all faradaic processes can be associated with pseudocapacitance. The question is how to differentiate pseudocapacitance related faradaic charge storage from the others. Therefore, attempts have been made to apply the band model for semiconductors to account qualitatively for the origin of pseudocapacitance. Capacitive and non-capacitive faradaic processes are then proposed to define and differentiate different charge storage mechanisms in supercapacitor and battery. On the other hand, the unequal electrode capacitance approach and the use of Ca2+ in aqueous electrolytes are discussed in relation with enhanced energy capacity of supercapacitors. In addition, the principle of supercapattery as a hybrid device is explained with recent literature examples
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