Bartonella quintana infective endocarditis in a homeless man with unexpected positive blood culture.

Bartonella species represent important causative agents of blood culture-negative infective endocarditis (IE). Their diagnosis represents a challenge for microbiologists and often relies on serological and molecular tools. However, even if the sensitivity of blood culture remains low, it should not be definitely ruled out. Indeed, we report the unusual case of a 22 year-old Guinean homeless man diagnosed with an IE due to Bartonella quintana. Unexpectedly, conventional blood cultures were positive after 13 days of incubation. Subculture was obtained on blood and chocolate agar, after 15 days of incubation in a 5 % CO2 atmosphere. Bacterial identification was obtained up to the species level using molecular tools (16S rRNA gene amplification and sequencing). A literature review of B. quintana blood culture-positive IE was conducted and revealed eighteen similar reported cases on a 25-year period. This case illustrates that, despite low sensitivity, Bartonella IE may be diagnosed thanks to prolonged blood culture.

Miscibility gap in the U-Nd-O phase diagram: a new approach of nuclear oxides in the environment?

To some extent, rare-earth-doped UO(2) is representative of an irradiated nuclear fuel. The two phases we observed previously in neodymium-doped UO(2) are now interpreted as the existence of a miscibility gap in the U-Nd-O phase diagram using new results obtained with Raman spectroscopy. Extrapolating the miscibility gap in the U-Nd-O phase diagram to irradiated UO(2) opens the path to a new understanding of nuclear oxides in the environment.

Eliminating the broadening by finite aperture in Brillouin spectroscopy.

We present a new optical arrangement which allows to avoid the broadening by finite aperture in Brillouin spectroscopy. In this system, all the rays scattered at the same angle by the whole scattering volume are collected on a single pixel of the area detector. This allows to use large collection angles, increasing the luminosity without lowering the accuracy of the frequency-shift and linewidth measurements. Several results of experimental checks are provided, showing the efficiency of the device.

Glass-specific behavior in the damping of acousticlike vibrations.

High frequency sound is observed in lithium diborate glass, Li2O-2B2O3, using Brillouin scattering of light and x rays. The sound attenuation exhibits a nontrivial dependence on the wave vector, with a remarkably rapid increase towards a Ioffe-Regel crossover as the frequency approaches the boson peak from below. An analysis of literature results reveals that the boson-peak frequency is closely related with a Ioffe-Regel limit for sound in many glasses. We conjecture that this relation, specific to glassy materials, might be rather common among them.