2,016 research outputs found

    Chemistry on the inside: green chemistry in mesoporous materials

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    An overview of the rapidly expanding area of tailored mesoporous solids is presented. The synthesis of a wide range of the materials is covered, both inorganically and organically modified. Their applications, in particular those relating to green chemistry, are also highlighted. Finally, potential future directions for these materials are discussed

    Scanning Electron Microscopy Observation of the Voltage Contrast Image of the Ferroelectric Domain Structure in the LiNbO3 Crystal

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    This paper reports a scanning electron microscopy study of the formation of the voltage contrast image of the ferroelectric domain structure in the LiNbO3 crystal. We investigated the formation of the pyroelectric voltage contrast image of the regular domain structure. For our experiment, we used ZY cut of a LiNbO3 crystal which had a regular domain structure with a domain width of -55 μm. The regular domain structure in the LiNbO3 crystal was formed by the method of thermo-electrical treatment after growth. The pyroelectric voltage contrast image of the regular domain structure in the scanning electron microscope was formed by applying the pyroelectric effect along polar axis Z. The difference in the voltage contrast in the neighboring domains connect with opposite directions of polar axis Z in the neighboring domains. It is shown that the voltage contrast of the ferroelectric domain structures is defined by the physical properties and orientation of the ferroelectric crystals

    Mouse Model of Respiratory Tract Infection Induced by Waddlia chondrophila.

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    Waddlia chondrophila, an obligate intracellular bacterium belonging to the Chlamydiales order, is considered as an emerging pathogen. Some clinical studies highlighted a possible role of W. chondrophila in bronchiolitis, pneumonia and miscarriage. This pathogenic potential is further supported by the ability of W. chondrophila to infect and replicate within human pneumocytes, macrophages and endometrial cells. Considering that W. chondrophila might be a causative agent of respiratory tract infection, we developed a mouse model of respiratory tract infection to get insight into the pathogenesis of W. chondrophila. Following intranasal inoculation of 2 x 108 W. chondrophila, mice lost up to 40% of their body weight, and succumbed rapidly from infection with a death rate reaching 50% at day 4 post-inoculation. Bacterial loads, estimated by qPCR, increased from day 0 to day 3 post-infection and decreased thereafter in surviving mice. Bacterial growth was confirmed by detecting dividing bacteria using electron microscopy, and living bacteria were isolated from lungs 14 days post-infection. Immunohistochemistry and histopathology of infected lungs revealed the presence of bacteria associated with pneumonia characterized by an important multifocal inflammation. The high inflammatory score in the lungs was associated with the presence of pro-inflammatory cytokines in both serum and lungs at day 3 post-infection. This animal model supports the role of W. chondrophila as an agent of respiratory tract infection, and will help understanding the pathogenesis of this strict intracellular bacterium

    ESR Study of (C_5H_{12}N)_2CuBr_4

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    ESR studies at 9.27, 95.4, and 289.7 GHz have been performed on (C5_5H12_{12}N)2_2CuBr4_4 down to 3.7 K. The 9.27 GHz data were acquired with a single crystal and do not indicate the presence of any structural transitions. The high frequency data were collected with a polycrystalline sample and resolved two absorbances, consistent with two crystallographic orientations of the magnetic sites and with earlier ESR studies performed at 300 K. Below BC1=6.6B_{C1}=6.6 T, our data confirm the presence of a spin singlet ground state.Comment: 2 pages, 4 figs., submitted 23rd International Conference on Low Temperature Physics (LT-23), Aug. 200

    Towards abundance estimates for jack mackerel in the South Pacific based on acoustic data collected by the commercial vessels

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    Pelagic trawlers make intensive use of echosounders and therefore could potentially be used as acoustic data collection platforms. This project investigated the possibility of collecting acoustic data and its potential utility to estimate fish stock biomass. The scope of the project was to develop and - when possible - test the tools that would be necessary for large scale data collection from commercial vessels, and investigate the suitability of acoustic data to derive abundance indices

    Preparing multi-partite entanglement of photons and matter qubits

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    We show how to make event-ready multi-partite entanglement between qubits which may be encoded on photons or matter systems. Entangled states of matter systems, which can also act as single photon sources, can be generated using the entangling operation presented in quant-ph/0408040. We show how to entangle such sources with photon qubits, which may be encoded in the dual rail, polarization or time-bin degrees of freedom. We subsequently demonstrate how projective measurements of the matter qubits can be used to create entangled states of the photons alone. The state of the matter qubits is inherited by the generated photons. Since the entangling operation can be used to generate cluster states of matter qubits for quantum computing, our procedure enables us to create any (entangled) photonic quantum state that can be written as the outcome of a quantum computer.Comment: 10 pages, 4 figures; to appear in Journal of Optics

    Space-time laser instabilities in homogeneously broadened dense media

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    We investigate the space-time dynamics of a homogeneously broadened single-mode laser when local field correction (LFC) is taken into account. We demonstrate that the Maxwell-Bloch equations modified by LFC admit travelling-wave solutions, as when LFC is not taken into account. Their stability is discussed and compared to the case without LFC

    Characterization of ion/electron beam induced deposition of electrical contacts at the sub-{\mu}m scale

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    We investigate the fabrication of electrical contacts using ion- and electron-beam induced deposition of platinum at the sub-\mu m scale. Halos associated with the metal surface decoration are characterized electrically in the 0.05-2 \mu m range using transport measurements, conducting atomic force microscopy and Kelvin probe microscopy. In contrast with IBID, EBID electrodes exhibit weakly conductive halos at the sub-\mu m scale, and can thus be used to achieve resist-free electrical contacts for transport measurements at the sub-\mu m scale. Four-point transport measurements using \mu m-spaced EBID contacts are provided in the case of a multiwalled carbon nanotube
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