Insights into electrochemiluminescent enhancement through electrode surface modification

The electrochemiluminescent (ECL) properties of a luminescent metal centre, [Ru(bpy)(3)](2+), can be significantly modulated through its electronic interaction with neighbouring centres and the polymer backbone used to confine it on an electrode surface. From the perspective of ECL based sensing devices, an increase in the ECL efficiency of a metallopolymer film can result in enhanced sensor sensitivity and selectivity. This work probes the ECL properties of both conjugated, [Ru(bpy)(2)(PPyBBIM)(10)](2+), and non-conjugated, [Ru(bpy)(2)(PVP)(10)](2+), ruthenium based metallopolymer films based on a well documented reaction with sodium oxalate, where bpy is 2,2'-bipyridyl, PPYBBIM is poly[2-(2-pyridyl)-bibenzimidazole] and PVP is poly(4-vinylpyridine). Through a combination of ground state electrochemical studies and ECL measurements, the ECL efficiency for each film is determined. This study reveals that despite a dramatic influence in charge transfer rates between metal centres, as observed for the conducting polymer, mediated through the conducting polymer backbone, a corresponding increase in ECL efficiency is not always observed. The degree of communication between the adjacent excited state metal centres are an important consideration for ECL enhancement however self quenching, luminophore distribution and film porosity must also be considered

Flexible High Speed Codec (FHSC)

The ongoing NASA/Harris Flexible High Speed Codec (FHSC) program is described. The program objectives are to design and build an encoder decoder that allows operation in either burst or continuous modes at data rates of up to 300 megabits per second. The decoder handles both hard and soft decision decoding and can switch between modes on a burst by burst basis. Bandspreading is low since the code rate is greater than or equal to 7/8. The encoder and a hard decision decoder fit on a single application specific integrated circuit (ASIC) chip. A soft decision applique is implemented using 300 K emitter coupled logic (ECL) which can be easily translated to an ECL gate array

AuNP-Agglomerated monoliths in pipette tips for lectin affinity extraction of glycoproteins

• To in situ fabricate ethylene dimethacrylate porous polymer monoliths within the confines of a commercial 20 μL polypropylene pipette tips. • To enhance the monolith surface area by immobilising AuNPs and then functionalise the AuNPs with ECL lectin for selective extraction of galactosylated proteins from complex media

Electrochemiluminescence (ECL) sensing properties of water soluble core-shell CdSe/ZnS quantum dots/Nafion composite films

Water soluble positively charged 2-(dimethylamino) ethanethiol (DAET)-protected core-shell CdSe/ZnS quantum dots (QDs) were synthesized and incorporated within negatively charged Nafion polymer films. The water soluble QDs were characterized using UV-visible and fluorescence spectroscopies. Nafion/QDs composite films were deposited on glassy carbon electrodes and characterized using cyclic voltammetry. The electrochemiluminescence (ECL) using hydrogen peroxide as co-reactant was enhanced for Nafion/QDs composite films compared to films of the bare QDs. Significantly, no ECL was observed for Nafion/QDs composite films when peroxydisulfate was used as the co-reactant, suggesting that the permselective properties of the Nafion effectively exclude the co-reactant. The ECL quenching by glutathione depends linearly on its concentration when hydrogen peroxide is used as the co-reactant, opening up the possibility to use Nafion/QDs composite films for various electroanalytical applications

Enhanced electrochemiluminescence from a stoichiometric ruthenium(II)-iridium(III) complex soft salt

The authors thank NSERC, CFI, FQRNT, PREA, and The University of Western Ontario for generous financial support to this research.Electrochemiluminescence (ECL) and electrochemistry are reported for a heterometallic soft salt, [Ru(dtbubpy)3][Ir(ppy)2(CN)2]2 ([Ir][Ru][Ir]), consisting of a 2:1 ratio of complementary charged Ru and Ir complexes possessing two different emission colors. The [Ru]2+ and [Ir]− moieties in the [Ir][Ru][Ir] greatly reduce the energy required to produce ECL. Though ECL intensity in the annihilation path was enhanced 18× relative to that of [Ru(bpy)3]2+, ECL in the co-reactant path with tri-n-propylamine was enhanced a further 4×. Spooling spectroscopy gives insight into ECL mechanisms: the unique light emission at 634 nm is due to the [Ru]2+* excited state and no [Ir]−* was generated in either route. Overall, the soft salt system is anticipated to be attractive and suitable for the development of efficient and low-energy-cost ECL detection systems.PostprintPeer reviewe

Cosmic history of integrated galactic stellar initial mass function : a simulation study

Theoretical and indirect observational evidences suggest that stellar initial mass function (IMF) increases with redshift. On the other hand star formation rates (SFR) may be as high as 100 $M_{\odot}$ yr$^{-1}$ in star burst galaxies. These may lead to formation of massive clusters hence massive stars to make the integrated galactic stellar initial mass function (IGIMF) top heavy (i.e. proportion of massive stars is higher than less massive stars). We investigate the joint effect of evolving IMF and several measures of SFR in dependence of galaxy wide IMF. The resulting IGIMF have slopes $\alpha_{2,IGIMF}$ in the high mass regime, which is highly dependent on the minimum mass of the embedded cluster ($M_{ecl,min}$), star formation rates and mass spectrum indices of embedded clusters (viz. $\beta$). It is found that for z $\sim$ 0 - 2, $\alpha_{2,IGIMF}$ becomes steeper (i.e. bottom heavy), for z $\sim$ 2 - 4, $\alpha_{2,IGIMF}$ becomes flatter (i.e. top heavy ) and from z $\sim$ 4 onwards $\alpha_{2,IGIMF}$ becomes again steeper. The effects are faster for higher values of $\beta$. $\alpha_{2,IGIMF}$ is flatter also for higher values of $M_{ecl,min}$. All these effects might be counted for the joint effect of increasing temperature of the ambient medium as well as varying SFR with increasing redshift.Comment: 46 pages, 11 figure

Extended Collective Licensing for the Use of Out-of-Commerce Works in Europe: A Matter of Legitimacy vis-à-vis Rights Owners

Extended Collective Licensing (ECL) schemes have been put forward inEurope as one of the solutions for the licensing of out-of-commerce works bycultural heritage institutions. ECL schemes extend the application of freely negotiated copyright licensing agreements between a user and a collective management organisation (CMO) to the works of non-members of the organisation. Not every CMO is suitable to license works under ECL provisions, however. In particular, the legitimacy of any agreement crucially relies on the ‘‘representativeness’’ of the CMO. This article focuses on the notion of representativeness of CMOs. On the basis of current European and national legislation, we argue that the representative character of a CMO encompasses three essential elements to be considered from the perspective of the rights owners: (1) the CMO must have a broad membership among the potential rights owners in the market it serves; (2) it must have a proper mandate from the rights owners in terms of category of works and rights covered; and (3) it must take appropriate measures to reach and inform (non-)members about the exercise of rights. ECL schemes can only be sufficiently legitimate to presume tacit approval by non-members if this assessment of the three criteria is carried out carefully.Extended Collective Licensing (ECL) schemes have been put forward inEurope as one of the solutions for the licensing of out-of-commerce works bycultural heritage institutions. ECL schemes extend the application of freely negotiated copyright licensing agreements between a user and a collective management organisation (CMO) to the works of non-members of the organisation. Not every CMO is suitable to license works under ECL provisions, however. In particular, the legitimacy of any agreement crucially relies on the ‘‘representativeness’’ of the CMO. This article focuses on the notion of representativeness of CMOs. On the basis of current European and national legislation, we argue that the representative character of a CMO encompasses three essential elements to be considered from the perspective of the rights owners: (1) the CMO must have a broad membership among the potential rights owners in the market it serves; (2) it must have a proper mandate from the rights owners in terms of category of works and rights covered; and (3) it must take appropriate measures to reach and inform (non-)members about the exercise of rights. ECL schemes can only be sufficiently legitimate to presume tacit approval by non-members if this assessment of the three criteria is carried out carefully