2,356 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

    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

    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

    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

    Statistical mechanics of systems with heterogeneous agents: Minority Games

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    We study analytically a simple game theoretical model of heterogeneous interacting agents. We show that the stationary state of the system is described by the ground state of a disordered spin model which is exactly solvable within the simple replica symmetric ansatz. Such a stationary state differs from the Nash equilibrium where each agent maximizes her own utility. The latter turns out to be characterized by a replica symmetry broken structure. Numerical results fully agree with our analytic findings.Comment: 4 pages, 1 Postscript figure. Revised versio

    Synergistic activity of sulbactam combined with colistin against colistin-resistant Acinetobacter baumannii

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    Acinetobacter baumannii is an emerging multidrug-resistant (MDR) pathogen that is responsible for community- and hospital-acquired infections that are difficult to control and treat [1]. With increasing antimicrobial resistance to carbapenems, colistin is often the treatment of last resort, however colistin-resistant clinical isolates have already been reported. Since therapeutic options are very limited or absent in some cases of infection with pandrug-resistant bacteria, there is an urgent need to find new antibiotic strategies

    Statistical-Mechanical Measure of Stochastic Spiking Coherence in A Population of Inhibitory Subthreshold Neurons

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    By varying the noise intensity, we study stochastic spiking coherence (i.e., collective coherence between noise-induced neural spikings) in an inhibitory population of subthreshold neurons (which cannot fire spontaneously without noise). This stochastic spiking coherence may be well visualized in the raster plot of neural spikes. For a coherent case, partially-occupied "stripes" (composed of spikes and indicating collective coherence) are formed in the raster plot. This partial occupation occurs due to "stochastic spike skipping" which is well shown in the multi-peaked interspike interval histogram. The main purpose of our work is to quantitatively measure the degree of stochastic spiking coherence seen in the raster plot. We introduce a new spike-based coherence measure MsM_s by considering the occupation pattern and the pacing pattern of spikes in the stripes. In particular, the pacing degree between spikes is determined in a statistical-mechanical way by quantifying the average contribution of (microscopic) individual spikes to the (macroscopic) ensemble-averaged global potential. This "statistical-mechanical" measure MsM_s is in contrast to the conventional measures such as the "thermodynamic" order parameter (which concerns the time-averaged fluctuations of the macroscopic global potential), the "microscopic" correlation-based measure (based on the cross-correlation between the microscopic individual potentials), and the measures of precise spike timing (based on the peri-stimulus time histogram). In terms of MsM_s, we quantitatively characterize the stochastic spiking coherence, and find that MsM_s reflects the degree of collective spiking coherence seen in the raster plot very well. Hence, the "statistical-mechanical" spike-based measure MsM_s may be used usefully to quantify the degree of stochastic spiking coherence in a statistical-mechanical way.Comment: 16 pages, 5 figures, to appear in the J. Comput. Neurosc

    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

    An unusual location of gouty panniculitis: A case report.

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    Gouty panniculitis, characterised by the deposition of monosodium urate crystals in subcutaneous tissue, is a rare clinical manifestation of gout. The case of a 67-year-old man is reported, who presented an erythematous nodule on the upper part of the right buttock suspicious for an abscess. This was in the context of chemotherapy for non-Hodgkin's lymphoma. Histopathologic examination demonstrated gouty panniculitis. Because infection was suspected, an incision was performed. The lesion was found to be densely calcified and friable, without purulent discharge. Therefore, a surgical en-bloc resection was performed. The wound healed slowly initially due to a combination of malnutrition, chemotherapy and infection. A wound infection with Enterococcus faecium was treated with antibiotic therapy (carbapenem for seven days) and local therapy. At 6-week follow up the wound showed good granulation tissue and was healing well by secondary intention. The patient was instructed to continue anti-hyperuricaemic treatment. In patients known to have long-standing hyperuricaemia and gout with nonspecific subcutaneous erythematous nodules, gouty panniculitis should be considered
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