232 research outputs found

    Scent releasing silicone septa: A versatile method for bioassays with volatiles

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    Volatile organic compounds are of great importance for communication within biological systems. For the experimental investigation of the functions of volatiles, methods for experimental manipulation are needed. Based on scent-release methods from pheromone research, we describe a simple and cheap method for scent manipulation using silicone rubber (i.e. a silicone septum). Volatile compounds are applied to the septum by soaking the septa for 1 h in a solvent/volatile solution. After removal of the septum from the solution and a drying period of 1 h to allow for evaporation of the solvent, the silicone emits the volatiles at a continuously decreasing rate for a minimum of 24 h. In this study, we measure the variability of the emission and quantify the emission of 22 common floral scent compounds at four different time points and in four different soaking concentrations. Our results show that for the same compound and soaking concentration, variability of volatile emission was low, showing the method leads to repeatable emission rates and can be fine-tuned to the desired emission rate. We provide a calculation tool based on linear regression to allow an experimenter to calculate soaking concentration for each of the 22 compounds to achieve a desirable emission from the septa, as well as to estimate the emission rate of a volatile from the septa after a given time

    Scent releasing silicone septa: A versatile method for bioassays with volatiles

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    Volatile organic compounds are of great importance for communication within biological systems. For the experimental investigation of the functions of volatiles, methods for experimental manipulation are needed. Based on scent-release methods from pheromone research, we describe a simple and cheap method for scent manipulation using silicone rubber (i.e. a silicone septum). Volatile compounds are applied to the septum by soaking the septa for 1 h in a solvent/volatile solution. After removal of the septum from the solution and a drying period of 1 h to allow for evaporation of the solvent, the silicone emits the volatiles at a continuously decreasing rate for a minimum of 24 h. In this study, we measure the variability of the emission and quantify the emission of 22 common floral scent compounds at four different time points and in four different soaking concentrations. Our results show that for the same compound and soaking concentration, variability of volatile emission was low, showing the method leads to repeatable emission rates and can be fine-tuned to the desired emission rate. We provide a calculation tool based on linear regression to allow an experimenter to calculate soaking concentration for each of the 22 compounds to achieve a desirable emission from the septa, as well as to estimate the emission rate of a volatile from the septa after a given time

    Legal situation and current practice of waste incineration bottom ash utilisation in Europe

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    Almost 500 municipal solid waste incineration plants in the EU, Norway, and Switzerland generate about 17.6 Mt/a of incinerator bottom ash (IBA). IBA contains minerals and metals. Metals are mostly separated and sold to the scrap market and minerals are either disposed of in landfills or utilised in the construction sector. Since there is no uniform regulation for IBA utilisation at EU level, countries developed own rules with varying requirements for utilisation. As a result from a cooperation network between European experts an up-to-date overview of documents regulating IBA utilisation is presented. Furthermore, this work highlights the different requirements that have to be considered. Overall, 51 different parameters for the total content and 36 different parameters for the emission by leaching are defined. An analysis of the defined parameter reveals that leaching parameters are significantly more to be considered compared to total content parameters. In order to assess the leaching behaviour nine different leaching tests, including batch tests, up-flow percolation tests and one diffusion test (monolithic materials) are in place. A further discussion of leaching parameters showed that certain countries took over limit values initially defined for landfills for inert waste and adopted them for IBA utilisation. The overall utilisation rate of IBA in construction works is approximately 54 wt.%. It is revealed that the rate of utilisation does not necessarily depend on how well regulated IBA utilisation is, but rather seems to be a result of political commitment for IBA recycling and economically interesting circumstances

    NNLO phase space master integrals for two-to-one inclusive cross sections in dimensional regularization

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    We evaluate all phase space master integrals which are required for the total cross section of generic 2 -> 1 processes at NNLO as a series expansion in the dimensional regulator epsilon. Away from the limit of threshold production, our expansion includes one order higher than what has been available in the literature. At threshold, we provide expressions which are valid to all orders in terms of Gamma functions and hypergeometric functions. These results are a necessary ingredient for the renormalization and mass factorization of singularities in 2 -> 1 inclusive cross sections at NNNLO in QCD.Comment: 37 pages, plus 3 ancillary files containing analytic expressions in Maple forma

    First histological observations on the incorporation of a novel nanocrystalline hydroxyapatite paste OSTIM(® )in human cancellous bone

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    BACKGROUND: A commercially available nanocrystalline hydroxyapatite paste Ostim(® )has been reported in few recent studies to surpass other synthetic bone substitutes with respect to the observed clinical results. However, the integration of this implantable material has been histologically evaluated only in animal experimental models up to now. This study aimed to evaluate the tissue incorporation of Ostim(® )in human cancellous bone after reconstructive bone surgery for trauma. METHODS: Biopsy specimens from 6 adult patients with a total of 7 tibial, calcaneal or distal radial fractures were obtained at the time of osteosynthesis removal. The median interval from initial operation to tissue sampling was 13 (range 3–15) months. Samples were stained with Masson-Goldner, von Kossa, and toluidine blue. Osteoid volume, trabecular width and bone volume, and cortical porosity were analyzed. Samples were immunolabeled with antibodies against CD68, CD56 and human prolyl 4-hydroxylase to detect macrophages, osteoblasts, and fibroblasts, respectively. TRAP stainings were used to identify osteoclasts. RESULTS: Histomorphometric data indicated good regeneration with normal bone turnover: mean osteoid volume was 1.93% of the trabecular bone mass, trabecular bone volume – 28.4%, trabecular width – 225.12 μm, and porosity index – 2.6%. Cortical and spongious bone tissue were well structured. Neither inflammatory reaction, nor osteofibrosis or osteonecrosis were observed. The implanted material was widely absorbed. CONCLUSION: The studied nanocrystalline hydroxyapatite paste showed good tissue incorporation. It is highly biocompatible and appears to be a suitable bone substitute for juxtaarticular comminuted fractures in combination with a stable screw-plate osteosynthesis

    Noise-induced switching between vortex states with different polarization in classical two-dimensional easy-plane magnets

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    In the 2-dimensional anisotropic Heisenberg model with XY-symmetry there are non-planar vortices which exhibit a localized structure of the z-components of the spins around the vortex center. We study how thermal noise induces a transition of this structure from one polarization to the opposite one. We describe the vortex core by a discrete Hamiltonian and consider a stationary solution of the Fokker-Planck equation. We find a bimodal distribution function and calculate the transition rate using Langer's instanton theory (1969). The result is compared with Langevin dynamics simulations for the full many-spin model.Comment: 15 pages, 4 figures, Phys. Rev. B., in pres

    The fully differential hadronic production of a Higgs boson via bottom quark fusion at NNLO

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    The fully differential computation of the hadronic production cross section of a Higgs boson via bottom quarks is presented at NNLO in QCD. Several differential distributions with their corresponding scale uncertainties are presented for the 8 TeV LHC. This is the first application of the method of non-linear mappings for NNLO differential calculations at hadron colliders.Comment: 27 pages, 13 figures, 1 lego plo

    Evaluation of a novel nanocrystalline hydroxyapatite paste Ostim® in comparison to Alpha-BSM® - more bone ingrowth inside the implanted material with Ostim® compared to Alpha BSM®

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    <p>Abstract</p> <p>Background</p> <p>The purpose of this study was to evaluate the performance a newly developed nanocrystalline hydroxyapatite, OSTIM<sup>® </sup>following functional implantation in femoral sites in thirty-eight sheep for 1, 2 or 3 months. Ostim<sup>® </sup>35 was compared to an established calcium phosphate, Alpha BSM<sup>®</sup>.</p> <p>Methods</p> <p>Biomechanical testing, μ-CT analysis, histological and histomorphological analyses were conducted to compare the treatments including evaluation of bone regeneration level, material degradation, implant biomechanical characteristics.</p> <p>Results</p> <p>The micro-computed tomography (μCT) analysis and macroscopic observations showed that Ostim<sup>® </sup>seemed to diffuse easily particularly when the defects were created in a cancellous bone area. Alpha BSM<sup>® </sup>remained in the defect.</p> <p>The performance of Ostim was good in terms of mechanical properties that were similar to Alpha BSM<sup>® </sup>and the histological analysis showed that the bone regeneration was better with Ostim<sup>® </sup>than with Alpha BSM<sup>®</sup>. The histomorphometric analysis confirmed the qualitative analysis and showed more bone ingrowth inside the implanted material with Ostim<sup>® </sup>when compared to Alpha BSM <sup>® </sup>at all time points.</p> <p>Conclusions</p> <p>The successful bone healing with osseous consolidation verifies the importance of the nanocrystalline hydroxyapatite in the treatment of metaphyseal osseous volume defects in the metaphyseal spongiosa.</p

    Competing orders in a magnetic field: spin and charge order in the cuprate superconductors

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    We describe two-dimensional quantum spin fluctuations in a superconducting Abrikosov flux lattice induced by a magnetic field applied to a doped Mott insulator. Complete numerical solutions of a self-consistent large N theory provide detailed information on the phase diagram and on the spatial structure of the dynamic spin spectrum. Our results apply to phases with and without long-range spin density wave order and to the magnetic quantum critical point separating these phases. We discuss the relationship of our results to a number of recent neutron scattering measurements on the cuprate superconductors in the presence of an applied field. We compute the pinning of static charge order by the vortex cores in the `spin gap' phase where the spin order remains dynamically fluctuating, and argue that these results apply to recent scanning tunnelling microscopy (STM) measurements. We show that with a single typical set of values for the coupling constants, our model describes the field dependence of the elastic neutron scattering intensities, the absence of satellite Bragg peaks associated with the vortex lattice in existing neutron scattering observations, and the spatial extent of charge order in STM observations. We mention implications of our theory for NMR experiments. We also present a theoretical discussion of more exotic states that can be built out of the spin and charge order parameters, including spin nematics and phases with `exciton fractionalization'.Comment: 36 pages, 33 figures; for a popular introduction, see http://onsager.physics.yale.edu/superflow.html; (v2) Added reference to new work of Chen and Ting; (v3) reorganized presentation for improved clarity, and added new appendix on microscopic origin; (v4) final published version with minor change
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