1,720,997 research outputs found
Computationally Accelerated Discovery of Efficient Dual Component White Light Emitters
No full textRaw data for a computationally guided approach to formulating solution-based white light emission from a series of H-bonded iridium phosphors and a complementary H-bonding fluorophore. We computationally investigated thirty new Ir(III) complexes which all incorporate a previously studied H-bond rich biguanide functionalised ligand. The results of the computational screening based on TD-DFT peak emission data and established lifetime and quantum efficiency data in the literature indicated seven Ir(III) candidates suitable for synthesis and further investigation. Of the seven Ir(III) complexes, four were chosen based on their synthetic feasibility and their suitability to further study based on the parameters of the screen. Photophysical investigations of these four candidates with our deep blue emitter showed how three out of four of the complexes could achieve near ideal white light in the appropriate ratio of the complementary H-bonding fluorophore, while all four host-guest-complements show promising white-light results in polymer (PMMA) films
Colour Tunability of Heteroleptic Ir(III) Complexes Through Second-Sphere Coordination
No full textRaw data for: Novel H-bond-rich iridium (III) complexes with different systems of cyclometalating ligands bearing the general formula [Ir(C^N)2(N^N)] were synthesized, characterized and their photophysical properties measured. The incorporated guanidine moieties allow us to introduce a hydrogen-bonding array for the formation of self-assembled iridium hydrogen-bonded systems. Through a series of UV-Vis binding studies we demonstrated the host-guest chemistry of these systems display high levels of colour tuneability. These hydrogen-bond interactions were also shown to have significant impacts on chromaticity, quantum yields and lifetimes with emphasis on energy transfer studies based on this second-sphere coordination approach.
KEYWORDS: H-Bonding, Colour tuning, Second-Sphere Interaction
Investigation of Sterol uptake by a new Beta-Cyclodextrin Porous Network
Get PDFThis report details the synthesis and analysis of new β-cyclodextrin (β-CD) networks: KβCD-MOF-1, KβCD-MOF-1-Chol and KβCD-MOF-2. Investigations of uptake of four sterols have also been conducted. The syntheses of the crystals were achieved by a vapour diffusion method at ambient temperature and pressure using mixtures of β-CD/potassium hydroxide in a ratio of 1:20, β-CD/potassium hydroxide/cholesterol in a ratio of 1:20:⅓ and β-CD/potassium benzoate in a ratio of 1:1, respectively. The analysis of crystals was performed using nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD) and optical and scanning electron microscopy. XRD showed KβCD-MOF-1 was made of accessible β-CD channels with each layer being perpendicular to the one above and the one below it. KβCD-MOF-1-Chol had a honeycomb like structure with cholesterol present in the β-CD channels. KβCD-MOF-2 was similar to a previously reported inclusion complex, although the crystallisation methods used were different.
Changes to crystal morphology of KβCD-MOF-1 and a control crystal were investigated using optical microscopy. The results of overnight soaking of these crystals using cholesterol dissolved in ethanol showed KβCD-MOF-1 crystal remained unchanged whilst the control crystal had nucleation occur on the edges.
Four types of sterols (Cholesterol, testosterone, beta-estradiol and deoxycholic acid) were used to investigate the uptake ratio of KβCD-MOF-1 and this was achieved using proton NMR analysis. The results showed that uptake of these sterols were successful. The NMR results also showed an inverse relation between numbers of polar groups in the sterol to the uptake by KβCD-MOF-1 network. The ratios of sterols:β-CD were observed to be 1:2, 1:4, 1:2 and 1:3 for cholesterol, testosterone, beta-estradiol and deoxycholic acid, respectively.
The encapsulations of UiO-66 crystals in to vesicles were investigated using fluorescence and electron microscopy. Although fluorescence microscopy provided some evidence of encapsulation however it was not confirmed by electron microscopy positively. Therefore the results remain inconclusive
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Bulk Remediation of Organophosphorus Contaminants using Metal-Organic Framework Polymer Composites
Get PDFOrganophosphorus (OP) chemical warfare agents (CWAs) are a group of deadly compounds which inhibit the enzyme acetyl cholinesterase and disrupt the normal functioning of the nervous system. Events in Damascus, Syria (2013) and Salisbury, United Kingdom (2018), have highlighted the dangers that these noxious agents still pose to civilian and military personnel. CWA degradation measures often employ an excess of stoichiometric reagents and solution buffers. There is therefore a demand for catalytic systems which can combat the CWA threat in the absence of additional reagents
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
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