A method for computing synchrotron and inverse-Compton emission from hydrodynamic simulations of supernova remnants

The observational signature of supernova remnants (SNRs) is very complex, in terms of both their geometrical shape and their spectral properties, dominated by non-thermal synchrotron and inverse-Compton scattering. We propose a post-processing method to analyse the broad-band emission of SNRs based on three-dimensional hydrodynamical simulations. From the hydrodynamical data, we estimate the distribution of non-thermal electrons accelerated at the shock wave and follow the subsequent evolution as they lose or gain energy by adiabatic expansion or compression and emit energy by radiation. As a first test case, we use a simulation of a bipolar supernova expanding into a cloudy medium. We find that our method qualitatively reproduces the main observational features of typical SNRs and produces fluxes that agree with observations to within a factor of a few. allowing for further use in more extended sets of models.Comment: 15 pages, 3 figures; accepted, HEDLA 2014 special issue of High Energy Density Physic

Maldi-tof Ms In The Clinical Microbiology Laboratory

Traditional methods for microbial identification are often very laborious and time consuming. A new mass spectrometry based technique, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF), has been described as a rapid, practical and low-cost method for this purpose. In this article, primary and possible future applications of this tool are briefly discussed © agosto 2013.494256259Anhalt, J.P., Fenselau, C., Identification of bacteria using mass spectrometry (1975) Anal Chem, 47, pp. 219-225Bittar, F., MALDI-TOF-MS for rapid detection of staphylococcal Panton-Valentine leukocidin (2009) Int J Antimicrob Agents, 34, pp. 467-470Bizzini, A., Greub, G., Matrix-assisted laser desorption ionization time-of-flight mass spectrometry, a revolution in clinical microbial identification (2010) Clin Microbiol Infect, 16, pp. 1614-1619Bizzini, A., Performance of matrix-assisted laser desorption ionization-time of flight mass spectrometry for identification of bacterial strains routinely isolated in a clinical microbiology laboratory (2010) J Clin Microbiol, 48, pp. 1549-1554Buchan, B.W., Riebe, K.M., Ledeboer, N.A., Comparison of the MALDI biotyper system using sepsityper specimen processing to routine microbiological methods for identification of bacteria from positive blood culture bottles (2012) J Clin Microbiol, 50, pp. 346-352Carbonnelle, E., Rapid identification of Staphylococci isolated in clinical microbiology laboratories by matrix-assisted laser desorption ionization-time of flight mass spectrometry (2007) J Clin Microbiol, 45, pp. 2156-2161Cherkaoui, A., Comparison of two matrix-assisted laser desorption ionization-time of flight mass spectrometry methods with conventional phenotypic identification for routine identification of bacteria to the species level (2010) J Clin Microbiol, 48, pp. 1169-1175Christner, M., Rapid identification of bacteria from positive blood culture bottles by use of matrix-assisted laser desorption-ionization time of flight mass spectrometry fingerprinting (2010) J Clin Microbiol, 48, pp. 1584-1591Croxatto, A., Prodhom, G., Greub, G., Applications of MALDI-TOF mass spectrometry in clinical diagnostic microbiology (2012) FEMS Microbiol Rev, 36, pp. 380-407Degand, N., Matrix-assisted laser desorption ionization-time of flight mass spectrometry for identification of nonfermenting gramnegative bacilli isolated from cystic fibrosis patients (2008) J Clin Microbiol, 46, pp. 3361-3367Drancourt, M., Detection of microorganisms in blood specimens using matrix-assisted laser desorption ionization time-of-flight mass spectrometry: A review (2010) Clin Microbiol Infect, 16, pp. 1620-1625Edwards-Jones, V., Rapid discrimination between methicillinsensitive and methicillin-resistant Staphylococcus aureus by intact cell mass spectrometry (2000) J Med Microbiol, 49, pp. 295-300Eigner, U., Performance of a matrix-assisted laser desorption ionization-time-of- flight mass spectrometry system for the identification of bacterial isolates in the clinical routine laboratory (2009) Clin Lab, 55, pp. 289-296Emonet, S., Application and use of various mass spectrometry methods in clinical microbiology (2010) Clin Microbiol Infect, 16, pp. 1604-1613Erhard, M., Identification of dermatophyte species causing onychomycosis and tinea pedis by MALDI-TOF mass spectrometry (2008) Exp Dermatol, 17, pp. 356-361Ferroni, A., Real-time identification of bacteria and Candida species in positive blood culture broths by matrix-assisted laser desorption ionization-time of flight mass spectrometry (2010) J Clin Microbiol, 48, pp. 1542-1548Grosse-Herrenthey, A., Challenging the problem of clostridial identification with matrix-assisted laser desorption and ionization-timeof- flight mass spectrometry (MALDI-TOF MS) (2008) Anaerobe, 14, pp. 242-249Hettick, J.M., Discrimination of Penicillium isolates by matrixassisted laser desorption/ionization time-of-flight mass spectrometry fingerprinting (2008) Rapid Commun Mass Spectrom, 22, pp. 2555-2560Hettick, J.M., Discrimination of Aspergillus isolates at the species and strain level by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry fingerprinting (2008) Anal Biochem, 380, pp. 276-281Kaleta, E.J., Comparative analysis of PCR-electrospray ionization/mass spectrometry (MS) and MALDI-TOF/MS for the identification of bacteria and yeast from positive blood culture bottles (2011) Clin Chem, 57, pp. 1057-1067Karas, M., Bachmann, D., Hillenkamp, F., Influence of the wavelength in high-irradiance ultraviolet laser desorption mass spectrometry of organic molecules (1985) Anal Chem, 57, pp. 2935-2939Scola, B.L.A., Raoult, D., Direct identification of bacteria in positive blood culture bottles by matrix-assisted laser desorption ionization timeof- flight mass spectrometry (2009) PLoS One, 4, pp. e8041Majcherczyk, P.A., The discriminatory power of MALDITOF mass spectrometry to differentiate between isogenic teicoplanin susceptible and teicoplanin-resistant strains of methicillin-resistant Staphylococcus aureus (2006) FEMS Microbiol Lett, 255, pp. 233-239Marinach-Patrice, C., Use of mass spectrometry to identify clinical Fusarium isolates (2009) Clin Microbiol Infect, 15, pp. 634-642Marinach, C., MALDI-TOF MS-based 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On the influence of a hybrid thermal-non-thermal distribution in the internal shocks model for blazars

Internal shocks occurring in blazars may accelerate both thermal and non-thermal electrons. While the non-thermal tail fills the higher end of the electron energy distribution (EED), thermal electrons populate the lowest energies of the shock-accelerated particles. In this paper, we examine the consequences that such a hybrid (thermal-non-thermal) EED has on the spectrum of blazars. Since the thermal component of the EED may extend to very low energies, the synchrotron emission of ultrarelativistic electrons may not be sufficiently accurate to compute blazar spectra. Thus, we replace the standard synchrotron process by the more general magneto-bremsstrahlung (MBS) mechanism encompassing the discrete emission of harmonics in the cyclotron regime, the transition from the discrete to continuum and the continuum emission in the synchrotron realm. In the γ-ray band, an EED of mostly thermal particles displays significant differences with respect to the one dominated by non-thermal particles. A thermally dominated EED produces a synchrotron self-Compton (SSC) peak extending only up to a few MeV, and the valley separating the MBS and the SSC peaks is much deeper than if the EED is dominated by non-thermal particles. The combination of these effects modifies the Compton dominance of a blazar, suggesting that the vertical scatter in the distribution of FSRQs and BL Lacs in the peak synchrotron frequency-Compton dominance parameter space could be attributed to different proportions of thermal/non-thermal particles in the EED of blazars

The effects of pneumoperitoneum and controlled ventilation on peritoneal lymphatic bacterial clearance: experimental results in rats

OBJECTIVE: To evaluate the effect of pneumoperitoneum, both alone and in combination with controlled ventilation, on peritoneal lymphatic bacterial clearance using a rat bacterial peritonitis model. METHOD: A total of 69 male Wistar rats were intraperitoneally inoculated with an Escherichia coli solution (109 colony-forming units (cfu)/mL) and divided into three groups of 23 animals each: A (control group), B (pneumoperitoneum under 5 mmHg of constant pressure), and C (endotracheal intubation, controlled ventilation, and pneumoperitoneum as in Group B). The animals were sacrificed after 30 min under these conditions, and blood, mediastinal ganglia, lungs, peritoneum, liver, and spleen cultures were performed. RESULTS: Statistical analyses comparing the number of cfu/sample in each of the cultures showed that no differences existed between the three groups. CONCLUSION: Based on our results, we concluded that pneumoperitoneum, either alone or in association with mechanical ventilation, did not modify the bacterial clearance through the diaphragmatic lymphatic system of the peritoneal cavity

Catching the Radio Flare in CTA 102 III. Core-Shift and Spectral Analysis

The temporal and spatial spectral evolution of the jets of AGN can be studied with multi-frequency, multi-epoch VLBI observations. The combination of both, morphological and spectral parameters can be used to derive source intrinsic physical properties such as the magnetic field and the non-thermal particle density. In the first two papers of this series, we analyzed the single-dish light curves and the VLBI kinematics of the blazar CTA 102 and suggested a shock-shock interaction between a traveling and a standing shock wave as a possible scenario to explain the observed evolution of the component associated to the 2006 flare. In this paper we investigate the core-shift and spectral evolution to test our hypothesis of a shock-shock interaction. We used 8 multi-frequency VLBA observations to analyze the temporal and spatial evolution of the spectral parameters during the flare. We observed CTA 102 between May 2005 and April 2007 using the VLBA at six different frequencies spanning from 2 - 86 GHz. After the calibrated VLBA images were corrected for opacity, we performed a detailed spectral analysis. From the derived values we estimated the magnetic field and the density of the relativistic particles. The detailed analysis of the opacity shift reveals that the position of the jet core is proportional to nu^-1 with some temporal variations. The value suggests possible equipartition between magnetic field energy and particle kinetic energy densities at the most compact regions. From the variation of the physical parameters we deduced that the 2006 flare in CTA 102 is connected to the ejection of a new traveling feature (t=2005.9) and the interaction between this shock wave and a stationary structure around 0.1 mas from the core. The source kinematics together with the spectral and structural variations can be described by helical motions in an over-pressured jet.Comment: 35 pages, 46 figure

Comparação entre cinco métodos para avaliação de susceptibilidade à oxacilina em cepas de Staphylococcus aureus isoladas de pacientes com fibrose cística

Staphylococcus aureus resistentes à oxacilina (MRSA) são, atualmente, um problema global. Pacientes com fibrose cística (FC) são frequentemente colonizados e infectados por MRSA. A realização de testes de susceptibilidade acurados é extremamente importante para o manejo da terapia antimicrobiana nesses indivíduos. Nesse estudo, realizamos comparação entre as acurácias de diversos testes de susceptibilidade à oxacilina, em cepas de S. aureus isoladas de pacientes com fibrose cística, tanto sensíveis como resistentes à oxacilina, com diferentes tipos de SCCmec, e utilizando a detecção do gene mecA como método padrão. A sensibilidade e a especificidade do disco de oxacilina, do Etest, e da placa de agar screening com oxacilina foram de 100%. A sensibilidade do disco de cefoxitina foi 85%, com especificidade de 100%. Em cepas clinicamente relevantes, a utilização combinada de mais de um método deveria ser considerada.Methicillin-resistant Staphylococcus aureus (MRSA) are now a worldwide problem. Cystic fibrosis (CF) patients are commonly colonized and infected by MRSA. Accurate oxacillin susceptibility testing is mandatory for the adequate management of these patients. We performed a comparison of the accuracy of different tests in CF isolates, including methicillin-susceptible S. aureus and MRSA with different SCCmec types, and using the mecA gene as the gold-standard. The sensitivity and specificity of oxacillin disc, Etest, and oxacillin agar screening plate were 100%. Sensitivity of the cefoxitin disc was 85% and specificity was 100%. For clinically relevant isolates, laboratories may consider the use of a combination of two phenotypic methods