117,660 research outputs found
Phenotype/genotype correlation and Cystic Fibrosis related Diabete Mellitus (italian multicentric study).
No full textStructural characterization of electrodeposited copper hexacyanoferrate films by using a spectroscopic multi-technique approach
No full textA deep structural investigation predominantly by X-ray spectroscopic techniques is conducted on films of copper hexacyanoferrate (CuHCF) deposited under different conditions, aimed at establishing structure-properties relationships. We show that the potentiodynamic electrosynthesis of CuHCF on carbon-based surfaces produces a highly disordered material, with a variable amount of Prussian Blue (PB). The subsequent Cu2+ intercalation induces the partial conversion of PB into CuHCF, which explains the improved electrocatalytic properties after the intercalation process. Both Cu and Fe K-edge data have been recorded. For the sample with the lower amount of PB, we could perform a multiple edge data analysis to determine the local atomic environment around both metal centres using the same set of structural parameters. The presence of high multiplicity Cu-N-C-Fe linear chains has allowed us to determine accurately the local environment of Fe while fitting the Cu K-edge data only. Using this approach we have retrieved structural information around Fe for those samples in which the concomitant presence of PB would have made impossible the analysis of the Fe K-edge. The Fe-C, C-N and Cu-N bond distances have been found in agreement with those of the bulk structures, but higher values of [Fe(CN)6] vacancies for the building blocks have been evidenced, reaching a value of ∼45% in one sample. XANES, Raman and SEM data agree with the model proposed for each studied electrode. © the Owner Societies
Tuning of hydrogen peroxide etching during the synthesis of silver nanoparticles. An application of triangular nanoplates as plasmon sensors for Hg2+ in aqueous solution
No full textA simple method to prepare silver nanoparticles (AgNPs) with different shapes and dimensions was optimized
by using a one-step reduction method with NaBH4, TSC and PVP, with H2O2 acting as an oxidation agent, to
etch the nanoparticles and produce different morphologies. A series of AgNPs were obtained with different colours,
including yellowto green and passing through orange, red, violet and blue, that exhibited different localized
surface plasmon resonance (LSPR) as analysed by UV–visible spectroscopy. The dimensions and morphologies of
the nanostructures were characterized in detail by scanning electron microscopy (SEM) and dynamic light scattering
(DLS) techniques. The characterizations showed different trends in the morphologies, starting fromspherical
to not well-defined structures, triangular nanoplates, hexagonal nanoplates and ultimately once again
showing quasi-spherical shapes. The triangular nanoplates were tested as plasmon sensors for mercury ions in
aqueous solution, and they showed an LSPR-blueshiftwith a change in colour fromblue to violet.When a calibration
curvewas measured in the concentration range from0.14 to 0.5 mg l−1, the nanoparticles showed good linearity
between the Hg2+ concentration in the solutions and the LSPR blueshift, with a correlation factor R2 of
0.9978 and an LOD of 0.013 mg l−1 (64.9 nM)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Structural and Interfacial Characterization of a Sustainable Si/Hard Carbon Composite Anode for Lithium-Ion Batteries
No full textThe effects of a biomass-derived hard carbon matrix and a sustainable cross-linked binder are investigated as electrode components for a silicon-based anode in lithium-ion half-cells, in order to reduce the capacity fade due to volume expansion and shrinkage upon cycling. Ex situ Raman spectroscopy and impedance spectroscopy are used to deeply investigate the structural and interfacial properties of the material within a single cycle and upon cycling. An effective buffering of the volume changes of the composite electrode is evidenced, even at a high Si content up to 30% in the formulation, resulting in the retention of structural and interfacial integrity. As a result, a high capacity performance and a very good rate capability are displayed even at high current densities, with a stable cycling behavior and low polarization effects
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Structural characterization of electrodeposited copper hexacyanoferrate films by using a spectroscopic multi- technique approach
No full textA deep structural investigation predominantly by X-Ray Spectroscopic techniques is conducted on films of copper hexacyanoferrate (CuHCF) deposited under different conditions, aimed at establishing structure-properties relationships. We show that the potentiodynamic electrosynthesis of CuHCF on carbon-based surfaces produces a highly disordered material, with a variable amount of Prussian Blue (PB). The subsequent Cu2+ intercalation induces the partial conversion of PB into CuHCF, which explains the improved electrocatalytic properties after the intercalation process. Both Cu and Fe K-edge data have been recorded. For the sample with the lower amount of PB, we could perform a multiple edge data analysis to determine the local atomic environment around both metal centres using the same set of structural parameters..
The presence of a high multiplicity Cu-N-C-Fe linear chains has allowed us to determine accurately the local environment of Fe while fitting the Cu K-edge data only. Using this approach we have retrieved structural information around Fe for those samples in which the concomitant presence of PB would have made impossible the analysis of the Fe K-edge.
The Fe-C, C-N and Cu-N bond distances have been found in agreement with those of the bulk structures, but higher values of [Fe(CN)6] vacancies for the building blocks have been evidenced, reaching a value of ~45% in one sample. XANES, Raman and SEM data agree to the model proposed of each studied electrode
- …
