735 research outputs found

    Detection and accurate identification of new or emerging bacteria in cystic fibrosis patients

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    AbstractRespiratory infections remain a major threat to cystic fibrosis (CF) patients. The detection and correct identification of the bacteria implicated in these infections is critical for the therapeutic management of patients. The traditional methods of culture and phenotypic identification of bacteria lack both sensitivity and specificity because many bacteria can be missed and/or misidentified. Molecular analyses have recently emerged as useful means to resolve these problems, including molecular methods for accurate identification or detection of bacteria and molecular methods for evaluation of microbial diversity. These recent molecular technologies have increased the list of new and/or emerging pathogens and epidemic strains associated with CF patients. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of intact cells has also emerged recently as a powerful and rapid method for the routine identification of bacteria in clinical microbiology laboratories and will certainly represent the method of choice also for the routine identification of bacteria in the context of CF. Finally, recent data derived from molecular culture-independent analyses indicate the presence of a previously underestimated, complex microbial community in sputa from CF patients. Interestingly, full genome sequencing of some bacteria frequently recovered from CF patients has highlighted the fact that the lungs of CF patients are hoT-SPOTs for lateral gene transfer and the adaptation of these ecosystems to a specific chronic condition

    Magnetic, thermal and transport properties of Cd doped CeIn3_3

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    We have investigated the effect of Cd substitution on the archetypal heavy fermion antiferromagnet CeIn3_3 via magnetic susceptibility, specific heat and resistivity measurements. The suppression of the Neel temperature, TN_{N}, with Cd doping is more pronounced than with Sn. Nevertheless, a doping induced quantum critical point does not appear to be achievable in this system. The magnetic entropy at TNT_N and the temperature of the maximum in resistivity are also systematically suppressed with Cd, while the effective moment and the Curie-Weiss temperature in the paramagnetic state are not affected. These results suggest that Cd locally disrupts the AFM order on its neighboring Ce moments, without affecting the valence of Ce. Moreover, the temperature dependence of the specific heat below TNT_N is not consistent with 3D magnons in pure as well as in Cd-doped CeIn3_3, a point that has been missed in previous investigations of CeIn3_3 and that has bearing on the type of quantum criticality in this system

    Quantitative study of molecular N_2 trapped in disordered GaN:O films

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    The structure of disordered GaN:O films grown by ion-assisted deposition is investigated using x-ray absorption near-edge spectroscopy and Raman spectroscopy. It is found that between 4 and 21 % of the nitrogen in the films is in the form of molecular N_2 that interacts only weakly with the surrounding matrix. The anion to cation ratio in the GaN:O host remains close to unity, and there is a close correlation between the N_2 fraction, the level of oxygen impurities, and the absence of short-range order in the GaN:O matrix.Comment: 5 pages, 3 figure

    Dynamics of Counterion Condensation

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    Using a generalization of the Poisson-Boltzmann equation, dynamics of counterion condensation is studied. For a single charged plate in the presence of counterions, it is shown that the approach to equilibrium is diffusive. In the far from equilibrium case of a moving charged plate, a dynamical counterion condensation transition occurs at a critical velocity. The complex dynamic behavior of the counterion cloud is shown to lead to a novel nonlinear force-velocity relation for the moving plate.Comment: 5 pages, 1 ps figure included using eps

    Compensation temperatures and exchange bias in La1.5Ca0.5CoIrO6

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    We report on the study of magnetic properties of the La1.5Ca0.5CoIrO6 double perovskite. Via ac magnetic susceptibility we have observed evidence of weak ferromagnetism and reentrant spin glass behavior on an antiferromagnetic matrix. Regarding the magnetic behavior as a function of temperature, we have found that the material displays up to three inversions of its magnetization, depending on the appropriate choice of the applied magnetic field. At low temperature the material exhibit exchange bias effect when it is cooled in the presence of a magnetic field. Also, our results indicate that this effect may be observed even when the system is cooled at zero field. Supported by other measurements and also by electronic structure calculations, we discuss the magnetic reversals and spontaneous exchange bias effect in terms of magnetic phase separation and magnetic frustration of Ir4+ ions located between the antiferromagnetically coupled Co ions.Comment: 10 pages, 8 figures and supplemental materia

    Impact of Manufacturing Equipment on Growth of Smallholder Agro-processing Industry in Bureti District, Kericho County, Kenya

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    A gradual shift from agriculture to industry has been witnessed in the pattern of economic growth in developing countries over the past decade. Agro-processing is being focused-on as the main driver of the transformation from primary agriculture to industry to provide additional income generating opportunities. Inspite of the emerging importance of agro-processing in the industrialization process its growth has been faced with the constraints of access to agro-processing technologies, especially among smallholder agribusinesses. This research sought to determine the extent to which access to manufacturing equipment impact on growth of smallholder agro-processing industry using a cross-sectional descriptive design. The study found that costs of acquiring manufacturing equipment and distances to sources of manufacturing equipment, as influential factors of access to technology, have inverse relationships with growth of smallholder agro-processing industry.For instance chi-square test for relationship between distances to manufacturing equipment sources and the number of smallholder agro-processing businesses set up was significant at 0.05 confidence level (ρ-value = 0.002). It was established that long distances travelled to purchase manufacturing equipment are critical impediments to growth in number of smallholder agro-processing businesses. Similar trends were observed between cost of manufacturing equipment and growth in number of agro-processing businesses as high costs of equipment constrained the access to – and – therefore reduced the rate of growth in number of small agro-processing businesses. Diversity of processing equipment was found to be low and had linear relationship with growth of the industry. It was therefore concluded that low level of access and narrow range of agro-manufacturing equipment significantly constrain the growth in number of smallholder agro-processing units. It was recommended that governments should create conducive environment for local manufacture of agro-manufacturing equipment as a strategy of stimulating and decentralizing agro-industrialization of rural areas

    Electronic properties of (Ga,Mn)N thin films with high Mn content

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    Optical and dc resistivity measurements as well as x-ray spectroscopies have been performed on (Ga,Mn)N films containing Mn at up to 11 at. %. The results indicate that at higher Mn contents, the Fermi level is situated within extended states, while GaN host interband optical transitions are unaffected. The Mn state is confirmed to be 3d⁵, as in the case of lower Mn content films; however, the high Mn content merges the 3d levels into a band located just below the host conduction band. The Fermi level is located within these Mn states just below the conduction band, in sharp contrast to its midgap position in fully crystalline, low Mn concentration materials. The difference in the position of the Fermi level at high Mn dopant levels has important implications for the promotion of ferromagnetism in this material.The authors gratefully acknowledge financial support from the New Zealand Foundation for Research Science and Technology through its New Economy Research Fund and through a postdoctoral fellowship of one of the authors B.J.R.. The work of the MacDiarmid Institute is supported by a New Zealand Centre of Research Excellence award. Another author S.G. wishes to thank Education New Zealand for financial support of the XANES measurements
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