Reduction of hospitalizations with diarrhea among children aged 0-5 years in Nouakchott, Mauritania, following the introduction of rotavirus vaccine.

INTRODUCTION: Rotavirus vaccine was introduced in Mauritania in December 2014. We investigated hospitalizations with diarrhea during pre and post-vaccination periods among children aged 0-5 years in Nouakchott, the capital of Mauritania. METHODS: We conducted a retrospective review of hospital admission registries from November 1st 2012 through October 31th 2017 at all referral hospitals in Nouakchott. We described admissions of children aged 0-5 years by diagnosis, data of admission, age and sex, and compared the proportion of all childhood hospitalizations with diarrhea before and after rotavirus vaccine introduction. RESULTS: In total, 6552 (19%) of all 34,329 hospitalizations in 0-5 year-olds had diarrhea. Of these, 3523/16,952 (20.7%) were recorded during the pre-vaccine period, 1373/6897 (19.9%) during the transition period (November 2014-October 2015), and 1656/10,480 (15.8%) during the post-vaccination period. The proportion of all childhood hospitalizations with diarrhea during the pre-vaccine period was 22.6% among males and 18.7% among females. Approximately one third (32.3%) of hospitalizations with diarrhea occurred in children aged 6-11 months. During the post-vaccination period, the proportion of hospitalizations with diarrhea declined by 24%, and the highest reduction (74%) was observed in children aged 2 to 5 years (P < 0.001). CONCLUSIONS: The proportion of childhood hospitalizations with diarrhea in Nouakchott was reduced by about one fourth after introduction of rotavirus vaccination in Mauritania, indicating a major impact for public health for children in the capital city.

Microfluidic-assisted Formation of Highly Monodisperse and Mesoporous Silica Soft Microcapsules.

The fabrication of mesoporous silica microcapsules with a highly controlled particle size ranging in the micrometer size presents a major challenge in many academic and industrial research areas, such as for the developement of smart drug delivery systems with a well controlled loading and release of (bio)active molecules. Many studies based on the solvent evaporation or solvent diffusion methods have been developed during the last two decades in order to control the particle size, which is often found to range at a sub-micrometer scale. Droplet-based microfluidics proved during the last decade a powerful tool to produce highly monodisperse and mesoporous silica solid microspheres with a controllable size in the micrometer range. We show in the present study, in contrast with previous microfluidic-assisted approaches, that a better control of the diffusion of the silica precursor sol in a surrounding perfluorinated oil phase during the silica formation process allows for the formation of highly monodisperse mesoporous silica microcapsules with a diameter ranging in the 10 micrometer range. We show also, using optical, scanning and transmission electron microscopies, small angle x-ray diffraction and BET measurements, that the synthesized mesoporous silica microcapsules exhibit a soft-like thin shell with a thickness of about 1 µm, across which 5.9 nm sized mesopores form a well-ordered hexagonal 2D network. We suggest and validate experimentally a model where the formation of such microcapsules is controlled by the solvent evaporation process at the droplet-air interface.

In vitro bioactivity of melt-derived glass 46S6 doped with magnesium.

Melt-derived glasses in the system SiO(2)-CaO-Na(2)O-P(2)O(5) were synthesized pure or doped with magnesium from 0.4 to 1.2 wt %, for applications as biomaterials in bony surgery. This chemical element has been chosen because of its high physiological interest. Its introduction for different contents in melt derived glasses has never been studied. The bioactivity of glasses was assessed by immersion of the samples in the simulated body fluid solution. Changes in glass surface morphology and composition after immersion were evaluated by several physico-chemical techniques. The aim of this work was to characterize the formation of the apatite-like layer at the glass surface, after in vitro assays and to evaluate the kinetic reaction between the glass and the surrounding synthetic fluids. Results indicate that magnesium influences the formation and the evolution of the newly formed layers: (1) it promotes the dissolution of the silica network, (2) it increases the thickness of the silica gel layer formed conventionally prior to the apatite-like layer, and (3) it slows down the crystallization of the apatite layer. However, the intensity of these effects depends on the content of magnesium introduced in the glass matrix.