753 research outputs found

    Adjuvant formulation for veterinary vaccines: Montanide™ Gel safety profile

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    AbstractSelecting the adjuvant is one of the key for the success of the vaccine in the field. Selecting a flexible adjuvant that will fit with several vaccines dedicated to one or more animal species is a source of economical efficiency. Frequently the safety or efficacy obtained with one model is different from another: there are few adjuvants fitting with the expectation of more than one animal species. Montanide™ Gel an innovative polymeric adjuvant have been tested in several animals. Our studies demonstrated the ability to use this adjuvant in dogs, cattle and pig vaccines. Three trials were performed to validate Montanide™ Gel ability to be used in cattle, pigs and dogs. Respectively, vaccines were formulated with ovalbumin in cattle, Pasteurella Multocida anatoxin and Bordetella bronchiseptica cell walls for pig and finally with parvovirus associated to two leptospira valence for dog model. All antigenic media used in the three trials were inactivated. In all trial, safety was followed through behaviour and temperature measurement as well as histology studies.Montanide™ Gel adjuvant can be used associated with a wide range of antigenic media. Nevertheless, the uses of such adjuvant need validation in avian and fish vaccines

    Three-dimensional flow instability in a lid-driven isosceles triangular cavity

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    Linear three-dimensional modal instability of steady laminar two-dimensional states developing in a lid-driven cavity of isosceles triangular cross-section is investigated theoretically and experimentally for the case in which the equal sides form a rectangular corner. An asymmetric steady two-dimensional motion is driven by the steady motion of one of the equal sides. If the side moves away from the rectangular corner, a stationary three-dimensional instability is found. If the motion is directed towards the corner, the instability is oscillatory. The respective critical Reynolds numbers are identified both theoretically and experimentally. The neutral curves pertinent to the two configurations and the properties of the respective leading eigenmodes are documented and analogies to instabilities in rectangular lid-driven cavities are discussed

    Polyproline is a minimal antifreeze protein mimetic and enhances the cryopreservation of cell monolayers

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    Tissue engineering, gene therapy, drug screening and emerging regenerative medicine therapies are fundamentally reliant on high-quality adherent cell culture, but current methods to cryopreserve cells in this format can give low cell yields and requires large volumes of solvent 'antifreezes'. Herein we report polyproline is a minimum (bio)synthetic mimic of antifreeze proteins, which is accessible by solution, solid phase and recombinant methods. We demonstrate that polyproline has ice recrystallization inhibition activity linked to its amphipathic helix and that it enhances the DMSO- cryopreservation of adherent cell lines. Polyproline may be a versatile additive in the emerging field of macromolecular cryoprotectants

    Pricing Bodies: A Feminist New Materialist Approach to the Relations Between the Economic and Socio-Cultural

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    Arguments that the economic and socio-cultural should be understood as relational and intertwined, and that price involves a reciprocal relationship between the economic and socio-cultural, are increasingly prevalent in the social sciences. I develop these notions of relationality and reciprocation through a feminist new materialist perspective, which emphasises the entanglement of and intra-action between what might usually be seen as independent and autonomous entities. To do this, I focus on a range of recent body-image initiatives, led by government, corporate and non-profit organisations, which aim to improve girls’ and young women’s levels of confidence and self-esteem. I explore how feminist theory tends to see such initiatives in terms of the expansion of the economic sphere into the socio-cultural, which involves a tainting or contamination of embodiment and feeling. Rather than dispute these arguments, I take seriously theories and practices from cultural economy that see the economic and socio-cultural as co-constitutive. I augment these ideas with a feminist new materialist approach and argue that the economic and socio-cultural are in intra-active relations: they do not precede or exist apart from each other. In doing so, I consider how body-image initiatives can be understood as phenomena produced through these entangled intra-active relations, and offer an understanding of pricing as a simultaneously socio-cultural and economic process, where value and values become. I also raise questions regarding how, ethically and politically, boundary making and unmaking can be conceived, and how despite being in entangled relations, asymmetries between economic and socio-cultural relations may be approached

    Adaptive mesh refinement with spectral accuracy for magnetohydrodynamics in two space dimensions

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    We examine the effect of accuracy of high-order spectral element methods, with or without adaptive mesh refinement (AMR), in the context of a classical configuration of magnetic reconnection in two space dimensions, the so-called Orszag-Tang vortex made up of a magnetic X-point centered on a stagnation point of the velocity. A recently developed spectral-element adaptive refinement incompressible magnetohydrodynamic (MHD) code is applied to simulate this problem. The MHD solver is explicit, and uses the Elsasser formulation on high-order elements. It automatically takes advantage of the adaptive grid mechanics that have been described elsewhere in the fluid context [Rosenberg, Fournier, Fischer, Pouquet, J. Comp. Phys. 215, 59-80 (2006)]; the code allows both statically refined and dynamically refined grids. Tests of the algorithm using analytic solutions are described, and comparisons of the Orszag-Tang solutions with pseudo-spectral computations are performed. We demonstrate for moderate Reynolds numbers that the algorithms using both static and refined grids reproduce the pseudo--spectral solutions quite well. We show that low-order truncation--even with a comparable number of global degrees of freedom--fails to correctly model some strong (sup--norm) quantities in this problem, even though it satisfies adequately the weak (integrated) balance diagnostics.Comment: 19 pages, 10 figures, 1 table. Submitted to New Journal of Physic

    Ultra-short pulses in linear and nonlinear media

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    We consider the evolution of ultra-short optical pulses in linear and nonlinear media. For the linear case, we first show that the initial-boundary value problem for Maxwell's equations in which a pulse is injected into a quiescent medium at the left endpoint can be approximated by a linear wave equation which can then be further reduced to the linear short-pulse equation. A rigorous proof is given that the solution of the short pulse equation stays close to the solutions of the original wave equation over the time scales expected from the multiple scales derivation of the short pulse equation. For the nonlinear case we compare the predictions of the traditional nonlinear Schr\"odinger equation (NLSE) approximation which those of the short pulse equation (SPE). We show that both equations can be derived from Maxwell's equations using the renormalization group method, thus bringing out the contrasting scales. The numerical comparison of both equations to Maxwell's equations shows clearly that as the pulse length shortens, the NLSE approximation becomes steadily less accurate while the short pulse equation provides a better and better approximation

    Templated Grain Growth in Macroporous Materials

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    We demonstrate a facile method to produce crystallographically textured, macroporous materials using a combination of modified ice templating and templated grain growth (TGG). The process is demonstrated on alumina and the lead-free piezoelectric material sodium potassium niobate. The method provides macroporous materials with aligned, lamellar ceramic walls which are made up of crystallographically aligned grains. Each method showed that the ceramic walls present a long-range order over the entire sample dimensions and have crystallographic texture as a result of the TGG process. We also present a modification of the March-Dollase equation to better characterize the overall texture of materials with textured but slightly misaligned walls. The controlled crystallographic and morphologic orientation at two different length scales demonstrated here can be the basis of multifunctional materials.Comment: 14 pages, 7 figures, 19 reference

    Magneto-shear modes and a.c. dissipation in a two-dimensional Wigner crystal

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    The a.c. response of an unpinned and finite 2D Wigner crystal to electric fields at an angular frequency ω\omega has been calculated in the dissipative limit, ωτ1\omega \tau \ll 1, where τ1\tau ^{-1} is the scattering rate. For electrons screened by parallel electrodes, in zero magnetic field the long-wavelength excitations are a diffusive longitudinal transmission line mode and a diffusive shear mode. A magnetic field couples these modes together to form two new magneto-shear modes. The dimensionless coupling parameter β=2(ct/cl)σxy/σxx\beta =2(c_{t}/c_{l})|\sigma_{xy}/\sigma_{xx}| where ctc_{t} and clc_{l} are the speeds of transverse and longitudinal sound in the collisionless limit and σxy\sigma_{xy} and σxx\sigma_{xx} are the tensor components of the magnetoconductivity. For β1\beta \geqslant 1, both the coupled modes contribute to the response of 2D electrons in a Corbino disk measurement of magnetoconductivity. For β1\beta \gg 1, the electron crystal rotates rigidly in a magnetic field. In general, both the amplitude and phase of the measured a.c. currents are changed by the shear modulus. In principle, both the magnetoconductivity and the shear modulus can be measured simultaneously.Comment: REVTeX, 7 pp., 4 eps figure
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