947 research outputs found
Observation of diffractive orbits in the spectrum of excited NO in a magnetic field
We investigate the experimental spectra of excited NO molecules in the
diamagnetic regime and develop a quantitative semiclassical framework to
account for the results. We show the dynamics can be interpreted in terms of
classical orbits provided that in addition to the geometric orbits, diffractive
effects are appropriately taken into account. We also show how individual
orbits can be extracted from the experimental signal and use this procedure to
reveal the first experimental manifestation of inelastic diffractive orbits.Comment: 4 fig
Identification of Rickettsiae from ticks collected in the Central African Republic using the polymerase chain reaction
Rickettsia mongolotimonae: a rare pathogen in France.
We report a second case of laboratory-confirmed infection caused by Rickettsia mongolotimonae in Marseille, France. This rickettsiosis may represent a new clinical entity; moreover, its geographic distribution may be broader than previously documented. This pathogen should be systematically considered in the differential diagnosis of atypical rickettsioses, especially rashless fevers with lymphangitis and lymphadenopathy, in southern France and perhaps elsewhere
Evidence of a Louse-Borne Outbreak Involving Typhus in Douai, 1710-1712 during the War of Spanish Succession
Background: The new field of paleomicrobiology allows past outbreaks to be identified by testing dental pulp of human remains with PCR. Methods: We identified a mass grave in Douai, France dating from the early XVIII th century. This city was besieged during the European war of Spanish succession. We tested dental pulp from 1192 teeth (including 40 from Douai) by quantitative PCR (qPCR) for R. prowazekii and B. quintana. We also used ultra-sensitive suicide PCR to detect R. prowazekii and genotyped positive samples. Results and Discussion: In the Douai remains, we identified one case of B. quintana infection (by qPCR) and R. prowazekii (by suicide PCR) in 6/21 individuals (29%). The R. prowazekii was genotype B, a genotype previously found in a Spanish isolate obtained in the first part of the XX th century. Conclusion: Louse-borne outbreaks were raging during the XVIII th century; our results support the hypothesis that typhus was imported into Europe by Spanish soldiers from America
Optimization of Generalized Multichannel Quantum Defect reference functions for Feshbach resonance characterization
This work stresses the importance of the choice of the set of reference
functions in the Generalized Multichannel Quantum Defect Theory to analyze the
location and the width of Feshbach resonance occurring in collisional
cross-sections. This is illustrated on the photoassociation of cold rubidium
atom pairs, which is also modeled using the Mapped Fourier Grid Hamiltonian
method combined with an optical potential. The specificity of the present
example lies in a high density of quasi-bound states (closed channel)
interacting with a dissociation continuum (open channel). We demonstrate that
the optimization of the reference functions leads to quantum defects with a
weak energy dependence across the relevant energy threshold. The main result of
our paper is that the agreement between the both theoretical approaches is
achieved only if optimized reference functions are used.Comment: submitte to Journal of Physics
Antibiotic susceptibility of Neochlamydia hartmanellae and Parachlamydia acanthamoebae in amoebae.
Parachlamydia acanthamoebae and Neochlamydia hartmanellae are Chlamydia-related bacteria naturally infecting free-living amoebae. These strict intracellular bacteria might represent emerging pathogens. Recent studies report an association with lower respiratory tract infections, especially with pneumonia where they have been identified as a potential causative agent in 1-2% of cases. In this study, we defined the antibiotic susceptibility of N. hartmanellae, two strains of P. acanthamoebae and two yet unclassified Parachlamydiaceae strains using a quantitative approach. We confirmed the results obtained earlier for P. acanthamoebae strain Bn9 in an observational study. Macrolides (MICs < 0.06-0.5 μg/ml), rifampicin (MICs 0.25-2) and doxycycline (2-4 μg/ml) were active against P. acanthamoebae strains and Neochlamydia. All strains were resistant to amoxicillin, ceftriaxone and imipenem (MIC ≥32 μg/ml). Similarly to other Chlamydia-related bacteria, all investigated Parachlamydiaceae were resistant to quinolones (MICs ≥ 16 μg/ml). Therefore, we recommend a treatment with macrolides for Parachlamydia-associated pneumonia
From cat scratch disease to endocarditis, the possible natural history of Bartonella henselae infection
BACKGROUND: Most patients with infectious endocarditis (IE) due to Bartonella henselae have a history of exposure to cats and pre-existing heart valve lesions. To date, none of the reported patients have had a history of typical cat scratch disease (CSD) which is also a manifestation of infection with B. henselae. CASE PRESENTATION: Here we report the case of a patient who had CSD and six months later developed IE of the mitral valve caused by B. henselae. CONCLUSION: Based on this unique case, we speculate that CSD represents the primary-infection of B. henselae and that IE follows in patients with heart valve lesions
- …