1,882 research outputs found

    Synthesis, Properties, and Solid-State Structures of a Series of 6,13-Dicyanoheteropentacene Analogues: Towards New Liquid Crystalline Materials

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    The focus of this thesis is the synthesis of novel heterocyclic pentacene analogs and the investigation of their self-organization for the development of new materials for organic electronics. The thesis consists of two interrelated projects: the first being development of an improved synthesis of a series of liquid crystalline dicyanotetraoxapentacenes (DCTOPs) while the second entails the exploratory synthesis of several novel dicyanoheteropentacene analogues and a preliminary investigation of their photophysical properties and solid-state structures. Both of these projects centre around the use of nucleophilic aromatic substitution reactions on tetrafluoroterephthalonitrile. Soluble, tetrakis(bis(alkoxy)phenyl)-substituted DCTOPs were originally synthesised via a short synthesis complicated by a tedious purification required in the last step. Despite this, derivatives bearing long alkyl chains were prepared which displayed liquid crystalline properties in addition to aggregation-induced emission. Building upon this success, but with the goal of achieving DCTOPs in an efficient synthetic manner for this thesis, changes were made which eliminated the troublesome fourfold Suzuki coupling by changing the order of reactions, which in turn required a protection-deprotection sequence. Purification in the new synthesis was greatly simplified and the target tetraaryl-DCTOPs were accessed in good overall yields and purities. The synthesis and solid state structures of these DCTOPs are discussed in Chapter 2. Building on the methods developed in Chapter 2, several novel pentacene analogues containing combinations of nitrogen, oxygen, and sulfur atoms installed within the pentacene core were also synthesised. These compounds were prepared in good yields, and preliminary photophysical studies show that all the compounds displayed luminescence in solution and the solid state. It was also shown that replacement of O with N leads to a red shift in absorption and emission spectra. The X-ray crystal structures show that several of these compounds exhibit π−stacking in the solid state, which is an important design element for applications in organic electronics. The synthesis, photophysical properties, and solid-state organization of these novel 6,13-dicyanoheteropentacene analogues are discussed in Chapter 3

    Copper(II)- and gold(III)-mediated cyclization of a thiourea to a substituted 2-aminobenzothiazole

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    Benzothiazole derivatives are a class of privileged molecules due to their biological activity and pharmaceutical applications. One route to these molecules is via intramolecular cyclization of thioureas to form substituted 2-aminobenzothiazoles, but this often requires harsh conditions or employs expensive metal catalysts. Herein, the copper(II)- and gold(III)-mediated cyclizations of thioureas to substituted 2-aminobenzothiazoles are reported. The single-crystal X-ray structures of the thiourea N-(3-methoxyphenyl)-N\u27- (pyridin-2-yl)thiourea, C13H13N3OS, and the intermediate metal complexes aquabis[5-methoxy-N-(pyridin-2-yl-κN)-1,3-benzothiazol-2-amine-κN3]copper(II) dinitrate, [Cu(C13H11N3OS)2(H2O)](NO3)2, and bis{2-[(5-methoxy-1,3-benzothiazol- 2-yl)amino]pyridin-1-ium} dichloridogold(I) chloride monohydrate, (C13H12N3OS)2[AuCl2]Cl⋅H2O, are reported. The copper complex exhibits a distorted trigonal–bipyramidal geometry, with direct metal-to-benzothiazoleligand coordination, while the gold complex is a salt containing the protonated uncoordinated benzothiazole, and offers evidence that metal reduction (in this case, AuIII to AuI) is required for the cyclization to proceed. As such, this study provides further mechanistic insight into the role of the metal cations in these transformations

    [2,2′-Imino­diethano­lato(2−)-κ3 O,N,O′][4-(meth­oxy­carbonyl­meth­yl)phen­yl]boron

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    The title compound, C13H18BNO4, was readily obtained from the reaction of methyl 4-boronobenzene acetate with ethano­lamine. A combination of inter­molecular N—H⋯O hydrogen bonds and C—H⋯π inter­actions leads to the pairwise association of mol­ecules

    Lessons from Expert Focus Groups on how to Better Support Adults with Mild Intellectual Disabilities to Engage in Co-Design

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    Co-design techniques generally rely upon higher-order cognitive skills, such as abstraction and creativity, meaning they may be inaccessible to people with intellectual disabilities (ID). Consequently, investigators must adjust the methods employed throughout their studies to ensure the complex needs of people with ID are appropriately catered to. Yet, there are a lack of guidelines to support researchers in this process, with previous literature often neglecting to discuss the decisions made during the development of their study protocols. We propose a new procedure to overcome this lack of support, by utilizing the knowledge of “experts” in ID to design a more accessible workshop for the target population. 12 experts across two focus groups were successful in identifying accessibility barriers throughout a set of typical early co-design activities. Recommendations to overcome these barriers are discussed along with lessons on how to better support people with ID to engage in co-design

    A Qualitative Study of an Integrated Maternity, Drugs and Social Care Service for Drug-using Women

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    Background: The care of drug-using pregnant women is a growing health and social care concern in many countries. A specialist clinic was established offering multidisciplinary care and advice to pregnant drug users in and around Aberdeen (UK) in 1997. The majority of women stabilise and reduce their drug use. By determining the needs and views of the women more appropriate services and prevention strategies may be developed. There has been little research conducted in this area and none in Scotland. Methods: This is a qualitative study that aimed to gain an understanding of the experiences of women drug users, seeking and receiving prenatal care and drug services from a specialist clinic. Twelve women participated in semi-structured one-to-one interviews. Results: The women preferred the multidisciplinary clinic (one-stop shop) to traditional prenatal care centred within General Practice. The relationships of the clients to the range of Clinic professionals and in hospital were explored as well as attitudes to Clinic care. The study participants attributed success in reducing their drug use to the combination of different aspects of care of the multi-agency clinic, especially the high level prenatal support. It is this arrangement of all aspects of care together that seem to produce better outcomes for mother and child than single care elements delivered separately. Some women reported that their pregnancy encouraged them to rapidly detoxify due to the guilt experienced. The most important aspects of the Clinic care were found to be non-judgemental attitude of staff, consistent staff, high level of support, reliable information and multi-agency integrated care. Conclusion: There is an impetus for women drug users to change lifestyle during pregnancy. The study highlighted a need for women to have access to reliable information on the effects of drugs on the baby. Further research is required to determine whether positive outcomes related to clinic attendance in the prenatal period are sustained in the postnatal period. Early referral to a specialist clinic is of benefit to the women, as they reported to receive more appropriate care, especially in relation to their drug use. A greater awareness of needs of the pregnant drug user could help the design of more effective prevention strategies

    First results on light readout from the 1-ton ArDM liquid argon detector for dark matter searches

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    ArDM-1t is the prototype for a next generation WIMP detector measuring both the scintillation light and the ionization charge from nuclear recoils in a 1-ton liquid argon target. The goal is to reach a minimum recoil energy of 30\,keVr to detect recoiling nuclei. In this paper we describe the experimental concept and present results on the light detection system, tested for the first time in ArDM on the surface at CERN. With a preliminary and incomplete set of PMTs, the light yield at zero electric field is found to be between 0.3-0.5 phe/keVee depending on the position within the detector volume, confirming our expectations based on smaller detector setups.Comment: 14 pages, 10 figures, v2 accepted for publication in JINS

    Crystallographic Education in the 21st Century

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    There are many methods that can be used to incorporate concepts of crystallography into the learning experiences of students, whether they are in elementary school, at university or part of the public at large. It is not always critical that those who teach crystallography have immediate access to diffraction equipment to be able to introduce the concepts of symmetry, packing or molecular structure in an age- and audience-appropriate manner. Crystallography can be used as a tool for teaching general chemistry concepts as well as general research techniques without ever having a student determine a crystal structure. Thus, methods for younger students to perform crystal growth experiments of simple inorganic salts, organic compounds and even metals are presented. For settings where crystallographic instrumentation is accessible (proximally or remotely), students can be involved in all steps of the process, from crystal growth, to data collection, through structure solution and refinement, to final publication. Several approaches based on the presentations in the MS92 Microsymposium at the IUCr 23rd Congress and General Assembly are reported. The topics cover methods for introducing crystallography to undergraduate students as part of a core chemistry curriculum; a successful short-course workshop intended to bootstrap researchers who rely on crystallography for their work; and efforts to bring crystallography to secondary school children and non-science majors. In addition to these workshops, demonstrations and long-format courses, open-format crystallographic databases and three-dimensional printed models as tools that can be used to excite target audiences and inspire them to pursue a deeper understanding of crystallography are described

    Cornish identities and migration: a multi-scalar approach

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    The definitive version is available at www.blackwell-synergy.com. 24 month embargo by the publisher. Article will be released July 2009.In this article we argue that theories of transnationalism have value in exploring the historical context of migration and that historical contexts help to shape such theoretical conceptualizations. Historians of migration have now begun to engage more directly with the literature of transnationalism, focusing on the networks that linked settler and home communities. Here we add to this by examining a nineteenth-century migrant community from a British region through the lens of transnationalism, applying the concept to the case of the Cornish, whose economic specialization produced culturally distinct Cornish communities on the mining frontiers of North America, Australia and South Africa. In doing so, we bring together the issues of scale and time. We review the multiple levels of the Cornish transnational space of the late nineteenth century, which exhibited aspects of both core transnationalism and translocalism. This waned, but in the later twentieth century, a renewed interest in a transnational Cornish identity re-emerged, articulating with changing identity claims in Cornwall itself. To capture better the experience of the Cornish over these two very different phases of transnationalism we identify another subset of transnationalism - that of transregionalism.Leverhulme Trus

    Studies on the virome of the entomopathogenic fungus Beauveria bassiana reveal novel dsRNA elements and mild hypervirulence.

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    © 2017 Kotta-Loizou, Coutts. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Kotta-Loizou I, Coutts RHA (2017) 'Studies on the Virome of the Entomopathogenic Fungus Beauveria bassiana Reveal Novel dsRNA Elements and Mild Hypervirulence', PLoS Pathogens, 13(1): e1006183. doi:10.1371/journal.ppat.1006183The entomopathogenic fungus Beauveria bassiana has a wide host range and is used as a biocontrol agent against arthropod pests. Mycoviruses have been described in phytopathogenic fungi while in entomopathogenic fungi their presence has been reported only rarely. Here we show that 21.3% of a collection of B. bassiana isolates sourced from worldwide locations, harbor dsRNA elements. Molecular characterization of these elements revealed the prevalence of mycoviruses belonging to the Partitiviridae and Totiviridae families, the smallest reported virus to date, belonging to the family Narnaviridae, and viruses unassigned to a family or genus. Of particular importance is the discovery of members of a newly proposed family Polymycoviridae in B. bassiana. Polymycoviruses, previously designated as tetramycoviruses, consist of four non-conventionally encapsidated capped dsRNAs. The presence of additional non-homologous genomic segments in B. bassiana polymycoviruses and other fungi illustrates the unprecedented dynamic nature of the viral genome. Finally, a comparison of virus-free and virus-infected isogenic lines derived from an exemplar B. bassiana isolate revealed a mild hypervirulent effect of mycoviruses on the growth of their host isolate and on its pathogenicity against the greater wax moth Galleria mellonella, highlighting for the first time the potential of mycoviruses as enhancers of biocontrol agents.Peer reviewedFinal Published versio
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