803 resultados para Elastomer rod
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The report provides a commentary on the UK poultry industry focusing on its structure, development and contribution to the UK agricultural economy. It also includes data on the economic performance of poultry businesses in England during 2008/09.
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A commentary on the UK poultry industry focusing on its structure, trends and development. Analysis includes the economic performance of poultry businesses in England during 2009/10.
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We report the cloning of an intermediate filament (IF) cDNA from the cephalochordate amphioxus that encodes a protein assignable to the type I keratin group. This is the first type I keratin reported from an invertebrate. Molecular phylogenetic analyses reveal that amphioxus also possesses a type II keratin, and that the genes encoding short-rod IF proteins underwent different patterns of duplication in vertebrates and their closest relatives, the cephalochordates. Extensive IF gene duplication and divergence may have facilitated the origin of new specialised cell types in vertebrates.
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ABSTRACT: The Institute of Psychoplasmics is a group exhibition dealing with cults, rituals and the metaphor of the body politic. A key interest of the project is the way in which cultic groupings challenge the integrity of the social body by producing another within it. The exhibition, book and events explore parallels between the operations of new religious movements in the context of neo-liberalism and the forms of collectivity posited by contemporary art. These issues were addressed through a gallery display, academic essays, discussion, adult and children focused workshops and live performance event. The exhibition design, which considered the gallery as a research institute, itself investigated strategies of collaboration and psycho-social manipulation. The show was curated by Pil and Galia Kollectiv and commissioned by the Pump House Gallery in London and supported by Outset, Arts Council England and the Henry Moore Foundation. The exhibition included work by a.a.s., Insectoid, Diann Bauer, Amanda Beech, Mikko Canini, Seth Coston, Rod Dickinson, Pil and Galia Kollectiv, Tai Shani, Francis Upritchard and Roman Vasseur. A publication edited by the curators, features writing by Suhail Malik, Amanda Beech, Pil and Galia Kollectiv, Gilad Elbom, Tom McCarthy, Emily McMehen and Travis Jeppesen.
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Nematic monodomain liquid crystalline elastomers have been prepared through in situ cross-linking of an acrylate based side-chain liquid crystalline polymer in a magnetic field. At the nematic–isotropic transition, the sample is found to undergo an anisotropic shape change. There is found to be an increase in dimensions perpendicular — and a decrease parallel — to the director, this is consistent with alignment of the polymer backbone parallel to the direction of mesogen alignment in the nematic state. From a quantitative investigation of this behaviour, we estimate the level of backbone anisotropy for the elastomer. As second measure of the backbone anisotropy, the monodomain sample was physically extended. We have investigated, in particular, the situation where a monodomain sample is deformed with the angle between the director and the extension direction approaching 90°. The behaviour on extension of these acrylate samples is related to alternative theoretical interpretations and the backbone anisotropy determined. Comparison of the chain anisotropy derived from these two approaches and the value obtained from previous small-angle neutron scattering measurements on deuterium labelled mixtures of the same polymer shows that some level of chain anisotropy is retained in the isotropic or more strictly weakly paranematic state of the elastomer. The origin and implications of this behaviour are discussed.
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Free-standing monodomain liquid crystal elastomer samples are shown to have a complete memory of the orientational configuration at the time of cross-linking. This memory is demonstrated through samples in which the parent polymer system is first aligned in a magnetic field prior to cross-linking. These films show reversible nematic-isotropic phase transitions and x-ray scattering patterns characteristic of nematic phases. The liquid crystal elastomer films exhibit a remarkable memory effect, in that the sample may be held at temperatures well above the nematic-isotropic transition for extended periods ( > 2 weeks), but on cooling into the liquid crystal phase region, both the original director alignment and the degree of preferred orientation are recovered. It is demonstrated that these novel memory effects are equilibrium in nature. The origins of this phenomena in terms of coupling between the mesogenic side-chains and the polymer network are discussed.
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The levels of alignment of the mesogenic units and of the polymer backbone trajectory for polyacrylate based nematic side-chain liquid crystal polymers and elastomers were evaluated by using wide angle X-ray and small angle neutron scattering procedures. The X-ray scattering measurements show that substantial levels of preferred orientation of the mesogenic units may be introduced through magnetic fields for uncrosslinked polymers and through mechanical extension for liquid crystal elastomers. Small angle neutron scattering measurements show that for highly aligned samples an anisotropic polymer backbone trajectory is observed in which the envelope is slightly extended by ∼ 10% in the direction parallel to the axis of alignment of the mesogenic units. The sense of this coupling differs from that recorded for other uncrosslinked side-chain liquid crystal polymers. Possible mechanisms to account for this anisotropy and its relationship to the properties of liquid crystal elastomers are discussed. The observed deformation behaviour of the liquid crystal elastomer is non-affine and this appears to confirm the dominating influence of the liquid crystal order of the side chains on the mechanical properties of these novel networks.
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The addition of small quantities of nanoparticles to conventional and sustainable thermoplastics leads to property enhancements with considerable potential in many areas of applications including food packaging 1, lightweight composites and high performance materials 2. In the case of sustainable polymers 3, the addition of nanoparticles may well sufficiently enhance properties such that the portfolio of possible applications is greatly increased. Most engineered nanoparticles are highly stable and these exist as nanoparticles prior to compounding with the polymer resin. They remain as nanoparticles during the active use of the packaging material as well as in the subsequent waste and recycling streams. It is also possible to construct the nanoparticles within the polymer films during processing from organic compounds selected to present minimal or no potential health hazards 4. In both cases the characterisation of the resultant nanostructured polymers presents a number of challenges. Foremost amongst these are the coupled challenges of the nanoscale of the particles and the low fraction present in the polymer matrix. Very low fractions of nanoparticles are only effective if the dispersion of the particles is good. This continues to be an issue in the process engineering but of course bad dispersion is much easier to see than good dispersion. In this presentation we show the merits of a combined scattering (neutron and x-ray) and microscopy (SEM, TEM, AFM) approach. We explore this methodology using rod like, plate like and spheroidal particles including metallic particles, plate-like and rod-like clay dispersions and nanoscale particles based on carbon such as nanotubes and graphene flakes. We will draw on a range of material systems, many explored in partnership with other members of Napolynet. The value of adding nanoscale particles is that the scale matches the scale of the structure in the polymer matrix. Although this can lead to difficulties in separating the effects in scattering experiments, the result in morphological studies means that both the nanoparticles and the polymer morphology are revealed.
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Between 1972 and 2001, the English late-modernist poet Roy Fisher provided the text for nine separate artist's books produced by Ron King at the Circle Press. Taken together, as Andrew Lambirth has written, the Fisher-King collaborations represent a sustained investigation of the various ways in which text and image can be integrated, breaking the mould of the codex or folio edition, and turning the book into a sculptural object. From the three-dimensional pop-up designs of Bluebeard's Castle (1973), each representing a part of the edifice (the portcullis, the armoury and so on), to ‘alphabet books’ such as The Half-Year Letters (1983), held in an ingenious french-folded concertina which can be stretched to over a metre long or compacted to a pocketbook, the project of these art books is to complicate their own bibliographic codes, and rethink what a book can be. Their folds and reduplications give a material form to the processes by which meanings are produced: from the discovery, in Top Down, Bottom Up (1990), of how to draw on both sides of the page at the same time, to the developments of The Left-Handed Punch (1987) and Anansi Company (1992), where the book becomes first a four-dimensional theatre space, in which a new version of Punch and Judy is played out by twelve articulated puppets, and then a location for characters that are self-contained and removable, in the form of thirteen hand-made wire and card rod-puppets. Finally, in Tabernacle (2001), a seven-drawer black wooden cabinet that stands foursquare like a sculpture (and sells to galleries and collectors for over three thousand pounds), the conception of the book and the material history of print are fully undone and reconstituted. This paper analyses how the King-Fisher art books work out their radically material poetics of the book; how their emphasis on collaboration, between artist and poet, image and text, and also book and reader – the construction of meaning becoming a co-implicated process – continuously challenges hierarchies and fixities in our conception of authorship; and how they re-think the status of poetic text and the construction of the book as material object.
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Soil viruses are potentially of great importance as they may influence the ecology and evolution of soil biological communities through both an ability to transfer genes from host to host and as a potential cause of microbial mortality. Despite this importance, the area of soil virology is understudied. Here, we report the isolation and preliminary characterisation of viruses from soils in the Dundee area of Scotland. Different virus morphotypes including tailed, polyhedral (spherical), rod shaped, filamentous and bacilliform particles were detected in the soil samples. An apparent predominance of small spherical and filamentous bacteriophages was observed, whereas tailed bacteriophages were significantly less abundant. In this report, we also present observations and characterisation of viruses from different soil functional domains surrounding wheat roots: rhizosheath, rhizosphere and bulk soil. In spite of the differences in abundance of bacterial communities in these domains, no significant variations in viral population structure in terms of morphology and abundance were found. Typically, there were approximately 1.1–1.2 × 109 virions g−1 dry weight, implicating remarkable differences in virus-to-bacteria ratios in domains close to roots, rhizosphere and rhizosheath (approximately 0.27) and in bulk soil (approximately 4.68).
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Duchenne muscular dystrophy is a severe X-linked inherited muscle wasting disorder caused by mutations in the dystrophin gene. Adeno-associated virus (AAV) vectors have been extensively used to deliver genes efficiently for dystrophin expression in skeletal muscles. To overcome limited packaging capacity of AAV vectors (<5 kb), truncated recombinant microdystrophin genes with deletions of most of rod and carboxyl-terminal (CT) domains of dystrophin have been developed. We have previously shown the efficiency of mRNA sequence–optimized microdystrophin (ΔR4-23/ΔCT, called MD1) with deletion of spectrin-like repeat domain 4 to 23 and CT domain in ameliorating the pathology of dystrophic mdx mice. However, the CT domain of dystrophin is thought to recruit part of the dystrophin-associated protein complex, which acts as a mediator of signalling between extracellular matrix and cytoskeleton in muscle fibers. In this study, we extended the ΔR4-23/ΔCT microdystrophin by incorporating helix 1 of the coiled-coil motif in the CT domain of dystrophin (MD2), which contains the α1-syntrophin and α-dystrobrevin binding sites. Intramuscular injection of AAV2/9 expressing CT domain–extended microdystrophin showed efficient dystrophin expression in tibialis anterior muscles of mdx mice. The presence of the CT domain of dystrophin in MD2 increased the recruitment of α1-syntrophin and α-dystrobrevin at the sarcolemma and significantly improved the muscle resistance to lengthening contraction–induced muscle damage in the mdx mice compared with MD1. These results suggest that the incorporation of helix 1 of the coiled-coil motif in the CT domain of dystrophin to the microdystrophins will substantially improve their efficiency in restoring muscle function in patients with Duchenne muscular dystrophy.
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This communication examines the suitability of a photo-patternable polydimethylsiloxane (PP-PDMS) elastomer as an insulating material for implantable microelectrodes. PP-PDMS is produced by mixing a photoinitiator (2-hydroxy-2-methylpropiophenone) with the PDMS base and curing agent. Subsequent exposure to UV radiation and development of the elastomeric “photo-resist” allows for the definition of well-defined openings within the PP-PDMS film. The dielectric constants of PP-PDMS and PDMS are similar (ε ≈ 2.6, f <;1MHz). Gold film microelectrodes patterned on glass or a PDMS substrate are encapsulated with PP-PDMS, while recording sites as small as 104 μm2 can be obtained in the PP-PDMS layer. The cytotoxicity of the PP-PDMS was preliminary tested in vitro by culturing 3T3 fibroblasts in PP-PDMS extracts. No adverse effects were observed in cultures exposed to PP-PDMS films initially leached in isopropanol solvent for 48h.
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To augment capacity-building for microbiome and probiotic research in Africa, a workshop was held in Nairobi, Kenya, at which researchers discussed human, animal, insect, and agricultural microbiome and probiotics/prebiotics topics. Five recommendations were made to promote future basic and translational research that benefits Africans.
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We study the orientational ordering on the surface of a sphere using Monte Carlo and Brownian dynamics simulations of rods interacting with an anisotropic potential. We restrict the orientations to the local tangent plane of the spherical surface and fix the position of each rod to be at a discrete point on the spherical surface. On the surface of a sphere, orientational ordering cannot be perfectly nematic due to the inevitable presence of defects. We find that the ground state of four +1/2 point defects is stable across a broad range of temperatures. We investigate the transition from disordered to ordered phase by decreasing the temperature and find a very smooth transition. We use fluctuations of the local directors to estimate the Frank elastic constant on the surface of a sphere and compare it to the planar case. We observe subdiffusive behavior in the mean square displacement of the defect cores and estimate their diffusion constants.
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Dystrophin is expressed only in muscle and brain, but is absent from all tissues of the adult mdx mouse, a mutant with a single base substitution in the dystrophin gene. The brains of both normal and mdx mice contain a protein of approximately 230 kDa that is recognised by anti-dystrophin antibodies raised to the N-terminal region of the rod-like domain. Although the N-terminal and central rod regions of dystrophin share structural homologies with spectrin, the 230-kDa protein represents neither of the presently described forms of brain spectrin by a variety of criteria (molecular weight, cerebellar localisation, and developmental regulation) and is distinct from the product of the dystrophin gene. Studies of mdx and normal mouse brain show different postnatal developmental regulation of the 230-kDa dystrophin-immunoreactive protein.