993 research outputs found

    Accessing the content of nineteenth-century periodicals: the Science in the Nineteenth-Century Periodical project

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    Nineteenth-century periodicals significantly outnumber books from that era, and present historians with an immensely valuable set of sources, but their use is constrained by the difficulty of identifying relevant material. For many periodicals, contents pages and volume indexes have been the only guide, and the few subject indexes that exist usually provide only an indication of the subjects mentioned in the article titles. By contrast, the Science in the Nineteenth-Century Periodical project (SciPer) indexed the science content of general-interest periodicals by skim-reading the entire text. The project’s approach to indexing is described and the relative merits of indexing and digitization in aiding researchers to locate relevant material are discussed. The article concludes that, notwithstanding the more sophisticated search interfaces of more recent retrodigitization projects, human indexing still has an important role to play in providing access to the content of historic periodicals and in mapping their data structure

    Magnetic susceptibility of alkali-TCNQ salts and extended Hubbard models with bond order and charge density wave phases

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    The molar spin susceptibilities χ(T)\chi(T) of Na-TCNQ, K-TCNQ and Rb-TCNQ(II) are fit quantitatively to 450 K in terms of half-filled bands of three one-dimensional Hubbard models with extended interactions using exact results for finite systems. All three models have bond order wave (BOW) and charge density wave (CDW) phases with boundary V=Vc(U)V = V_c(U) for nearest-neighbor interaction VV and on-site repulsion UU. At high TT, all three salts have regular stacks of TCNQ\rm TCNQ^- anion radicals. The χ(T)\chi(T) fits place Na and K in the CDW phase and Rb(II) in the BOW phase with VVcV \approx V_c. The Na and K salts have dimerized stacks at T<TdT < T_d while Rb(II) has regular stacks at 100K. The χ(T)\chi(T) analysis extends to dimerized stacks and to dimerization fluctuations in Rb(II). The three models yield consistent values of UU, VV and transfer integrals tt for closely related TCNQ\rm TCNQ^- stacks. Model parameters based on χ(T)\chi(T) are smaller than those from optical data that in turn are considerably reduced by electronic polarization from quantum chemical calculation of UU, VV and tt on adjacent TCNQ\rm TCNQ^- ions. The χ(T)\chi(T) analysis shows that fully relaxed states have reduced model parameters compared to optical or vibration spectra of dimerized or regular TCNQ\rm TCNQ^- stacks.Comment: 9 pages and 5 figure

    The K186E amino acid substitution in the canine influenza virus H3N8 NS1 protein restores its ability to inhibit host gene expression

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    Canine influenza viruses (CIVs) are the causative agents of canine influenza, a contagious respiratory disease in dogs, and include the equine-origin H3N8 and the avian-origin H3N2. Influenza A virus (IAV) non-structural protein 1 (NS1) is a virulence factor essential for counteracting the innate immune response. Here, we evaluated the ability of H3N8 CIV NS1 to inhibit host innate immune responses. We found that H3N8 CIV NS1 was able to efficiently counteract interferon (IFN) responses but was unable to block general gene expression in human or canine cells. Such ability was restored by a single amino acid substitution in position 186 (K186E) that resulted in NS1 binding to the 30-kDa subunit of the cleavage and polyadenylation specificity factor (CPSF30), a cellular protein involved in pre-mRNA processing. We also examined the frequency distribution of K186 and E186 among H3N8 CIVs and equine influenza viruses (EIVs), the ancestors of H3N8 CIV, and experimentally determined the impact of amino acid 186 in the ability of different CIV and EIV NS1s to inhibit general gene expression. In all cases, the presence of E186 was responsible for the control of host gene expression. Contrastingly, the NS1 protein of H3N2 CIV harbors E186 and blocks general gene expression in canine cells. Altogether, our results confirm previous studies on the strain-dependent ability of NS1 to block general gene expression. Moreover, the observed polymorphism on amino acid 186 between H3N8 and H3N2 CIVs might be the result of adaptive changes acquired during long-term circulation of avian-origin IAVs in mammals. IMPORTANCE: Canine influenza is a respiratory disease of dogs caused by two CIV subtypes, the H3N8 and H3N2 viruses of equine and avian origin, respectively. Influenza NS1 is the main viral factor responsible for the control of host innate immune responses and changes in NS1 can play an important role in host adaptation. Here we assessed the ability of H3N8 CIV NS1 to inhibit host innate immune responses and gene expression. The H3N8 CIV NS1 did not block host gene expression but this activity was restored by a single amino acid substitution (K186E), which was responsible for NS1 binding to the host factor CPSF30. In contrast, the H3N2 CIV NS1, that contains E186, blocks general gene expression. Our results suggest that the ability to block host gene expression is not required for influenza replication in mammals but might be important in the long-term adaptation of avian-origin influenza viruses to mammals

    Diels–Alder cycloaddition and RAFT chain end functionality::an elegant route to fullerene end-capped polymers with control over molecular mass and architecture

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    Fullerene C60 functionalised polymers (FFPs) have found numerous applications from photovoltaic devices to materials for photodynamic therapy. Polymer end-capping is one way to fabricate FFPs since it provides enhanced control over the macromolecular architecture and composition. This paper reports, for the first time, a facile, metal catalyst-free approach to FFPs where polymers, generated by reversible-addition fragmentation chain transfer (RAFT) polymerisation, were coupled to a fullerene derivative through chain-end functionality, provided by the chain transfer agent without further modification. Two routes to a fullerene derivative were compared – based on the Prato reaction and Diels–Alder cycloaddition. The Diels–Alder route exclusively yielded the mono-addition product, whereas the Prato route resulted in a mixture of mono- and diadducts which required further separation. This elegant combination of well-defined RAFT polymerisation and precise Diels–Alder addition allowed one to obtain fullerene end-capped polymers within a wide range of molecular masses (from 5000 to 50 000 g mol−1)

    A temperature sensitive live-attenuated canine influenza virus H3N8 vaccine

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    Canine influenza is a respiratory disease of dogs caused by canine influenza virus (CIV). CIV subtypes responsible for influenza in dogs include H3N8, which originated from the transfer of H3N8 equine influenza virus to dogs; and the H3N2 CIV, which is an avian-origin virus that adapted to infect dogs. Influenza infections are most effectively prevented through vaccination to reduce transmission and future infection. Currently, only inactivated influenza vaccines (IIVs) are available for the prevention of CIV in dogs. However, the efficacy of IIVs is suboptimal, and novel approaches are necessary for the prevention of disease caused by this canine respiratory pathogen. Using reverse genetics techniques, we have developed a live-attenuated CIV vaccine (LACIV) for the prevention of H3N8 CIV. The H3N8 LACIV replicates efficiently in canine cells at 33°C but is impaired at temperatures of 37 to 39°C and was attenuated compared to wild-type H3N8 CIV in vivo and ex vivo. The LACIV was able to induce protection against H3N8 CIV challenge with a single intranasal inoculation in mice. Immunogenicity and protection efficacy were better than that observed with a commercial CIV H3N8 IIV but provided limited cross-reactive immunity and heterologous protection against H3N2 CIV. These results demonstrate the feasibility of implementing a LAIV approach for the prevention and control of H3N8 CIV in dogs and suggest the need for a new LAIV for the control of H3N2 CIV. Importance: Two influenza A virus subtypes has been reported in dogs in the last 16 years: the canine influenza viruses (CIV) H3N8 and H3N2 of equine and avian origins, respectively. To date, only inactivated influenza vaccines (IIVs) are available to prevent CIV infections. Here, we report the generation of a recombinant, temperature-sensitive H3N8 CIV as a live-attenuated influenza vaccine (LAIV), which was attenuated in mice and dog tracheal, explants compared to CIV H3N8 wild type. A single dose of H3N8 LACIV showed immunogenicity and protection against a homologous challenge that was better than that conferred with an H3N8 IIV, demonstrating the feasibility of implementing a LAIV approach for the improved control of H3N8 CIV infections in dogs

    Uso de fontes em aulas de História e conciência histórica: encaminhamentos e discussões teóricas

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    Anais do XVII Congresso Internacional das Jornadas de Educaão História - teoria, pesquisa e prática - I Encontro da AIPEDH - Associação Iber-Americana de Pesquisadores em Educação História, realizado pela Universidade Federal da Integração Latino-Americana, entre 02, 03 e 04 de agosto de 2017.Este trabalho apresenta os encaminhamentos de uma pesquisa iniciada no curso de graduação em História na Universidade Estadual de Londrina, e prossegue como parte das discussões que estão sendo realizadas no Mestrado do Programa de Pós-Graduação em Educação da mesma universidade, sob orientação da Professora Dra. Marlene Rosa Cainelli. A investigação realizada tem como objetivo principal o estudo do uso de fontes no ensino de história, mais especificamente sobre a literatura em aulas de história na perspectiva da Educação Histórica, tendo como tema adaptações do clássico “Os Miseráveis”, de Victor Hugo. A pesquisa atual trata do uso de uma versão em História em Quadrinhos (HQ) da obra, buscando verificar como HQs podem contribuir para o desenvolvimento da consciência histórica dos alunos. Para tanto, utilizamo-nos, entre outros, dos escritos de Rüsen (2011) sobre a consciência histórica e Fronza (2007, 2012) sobre o uso de quadrinhos relacionados a temáticas históricasCAPE

    Tuneable denture adhesives using biomimetic principles for enhanced tissue adhesion in moist environments

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    Nature provides many interesting examples of adhesive strategies. Of particular note, the protein glue secreted by marine mussels delivers high adhesion in wet and dynamic environments owing to existence of catechol moieties. As such, this study focuses on denture fixatives, where a non-zinc-containing commercial-based formulation has been judiciously modified by a biomimetic catechol-inspired polymer, poly(3,4-dihydroxystyrene/styrene-alt-maleic acid) in a quest to modulate adhesive performance. In vitro studies, in a lap-shear configuration, revealed that the catechol-modified components were able to enhance adhesion to both the denture base and hydrated, functional oral tissue mimic, with the resulting mode of failure prominently being adhesive rather than cohesive. These characteristics are desirable in prosthodontic fixative applications, for which temporary adhesion must be maintained, with ultimately an adhesive failure from the mucosal tissue surface preferred. These insights provide an experimental platform in the design of future biomimetic adhesive systems. Statement of Significance: Mussel adhesive proteins have proven to be promising biomimetic adhesive candidates for soft tissues and here for the first time we have adapted marine adhesive technology into a denture fixative application. Importantly, we have incorporated a soft tissue mimic in our in vitro adhesion technique that more closely resembles the oral mucosa than previously studied substrates. The novel biomimetic-modified adhesives showed the ability to score the highest adhesive bonding out of all the formulations included in this study, across all moisture levels.This paper will be of major interest to the Acta Biomaterialia readership since the study has illustrated the potential of biomimetic principles in the design of effective prosthodontic tissue adhesives in a series of purpose-designed in vitro experiments in the context of the challenging features of the oral environment

    Hydrogen bonding in acrylamide and its role in the scattering behavior of acrylamide-based block copolymers

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    Hydrogen bonding plays a role in the microphase separation behavior of many block copolymers, such as those used in lithography, where the stronger interactions due to H-bonding can lead to a smaller period for the self-assembled structures, allowing the production of higher resolution templates. However, current statistical thermodynamic models used in descriptions of microphase separation, such as the Flory-Huggins approach, do not take into account some important properties of hydrogen bonding, such as site specificity and cooperativity. In this combined theoretical and experimental study, a step is taken toward the development of a more complete theory of hydrogen bonding in polymers, using polyacrylamide as a model system. We begin by developing a set of association models to describe hydrogen bonding in amides. Both models with one association constant and two association constants are considered. This theory is used to fit IR spectroscopy data from acrylamide solutions in chloroform, thereby determining the model parameters. These parameters are then employed to calculate the scattering function of the disordered state of a diblock copolymer with one polyacrylamide block and one non-hydrogen-bonding block in the random phase approximation. It is then shown that the expression for the inverse scattering function with hydrogen bonding is the same as that without hydrogen bonding, but with the Flory-Huggins parameter χ replaced by an effective value χeff=χ+δχHB(f), where the hydrogen-bonding contribution δχHB depends on the volume fraction f of the hydrogen-bonding block. We find that models with two constants give better predictions of bond energy in the acrylamide dimer and more realistic asymptotic behavior of the association constants and δχHB in the limit of high temperatures

    Hydrogen Bonding Aggregation in Acrylamide: Theory and Experiment

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    Hydrogen bonding plays a role in the microphase separation behavior of many block copolymers, such as those used in lithography, where the stronger interactions due to hydrogen bonding can lead to a smaller period for the self-assembled structures, allowing the production of higher resolution templates. However, current statistical thermodynamic models used in descriptions of microphase separation, such as the Flory–Huggins approach, do not take into account some important properties of hydrogen bonding, such as site specificity and cooperativity. In this combined theoretical and experimental study, a step is taken toward the development of a more complete theory of hydrogen bonding in polymers, using polyacrylamide as a model system. We begin by developing a set of association models to describe hydrogen bonding in amides. Both models with one association constant and two association constants are considered. This theory is used to fit IR spectroscopy data from acrylamide solutions in chloroform, thereby determining the model parameters. We find that models with two constants give better predictions of bond energy in the acrylamide dimer and more realistic asymptotic behavior of the association constants in the limit of high temperatures. At the end of the paper, we briefly discuss the question of the determination of the Flory–Huggins parameter for a diblock copolymer with one self-associating hydrogen bonding block and one non-hydrogen bonding block by means of fitting the scattering function in a disordered state
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