Direct Observation of PFIB-Induced Clustering in Precipitation-Strengthened Al Alloys by Atom Probe Tomography.

The effect of sample preparation on a pre-aged Al­Mg­Si­Cu alloy has been evaluated using atom probe tomography. Three methods of preparation were investigated: electropolishing (control), Ga+ focused ion beam (FIB) milling, and Xe+ plasma FIB (PFIB) milling. Ga+-based FIB preparation was shown to introduce significant amount of Ga contamination throughout the reconstructed sample (≈1.3 at%), while no Xe contamination was detected in the PFIB-prepared sample. Nevertheless, a significantly higher cluster density was observed in the Xe+ PFIB-prepared sample (≈25.0 × 1023 m−3) as compared to the traditionally produced electropolished sample (≈3.2 × 1023 m−3) and the Ga+ FIB sample (≈5.6 × 1023 m−3). Hence, the absence of the ion milling species does not necessarily mean an absence of specimen preparation defects. Specifically, the FIB and PFIB-prepared samples had more Si-rich clusters as compared to electropolished samples, which is indicative of vacancy stabilization via solute clustering.

[A public health intervention at the time of a case of rabies in Quebec]. / Intervention de la santé publique lors de la survenue d'un cas de rage humaine au Québec.

BACKGROUND: In the fall of 2000, a nine-year-old child living in Montreal (Québec) died of rabies encephalitis. Cases of human rabies had not been reported in Canada for 15 years. The molecular characterization of viral nucleic acid implicated the Ln/Ps variant associated with the silver-haired bat and the eastern pipistrelle. This article describes and analyzes the intervention carried out by public health. INTERVENTION AND DISCUSSION: The investigation revealed that contact with the bat must have occurred while the child was sleeping. Following the search for close contacts of the reference case, rabies postexposure prophylaxis (RPEP) was recommended to 59 people (3 household contacts, 12 playmates and 44 health care workers). Discussion with other public health departments in the province was important because of the media coverage of this case, which led to a considerable increase in the number of reported exposures to bats and in RPEP administration. CONCLUSION: Lessons learned from this event are that rapid and coordinated action with all stakeholders is essential to the success of this type of public health intervention and that the population must be informed of the risk of rabies transmission from bats.

[Why are some children incompletely vaccinated at the age of 2?]. / Pourquoi certains enfants sontincomplètement vaccinés à l'âgede 2 ans?

OBJECTIVE: A survey was conducted in the Province of Quebec to document the factors associated with an incomplete immunization status among 2-year-old children. METHODS: Parents of 430 completely and 266 partially vaccinated children selected from the computerized vaccination register agreed to participate. RESULTS: The non-simultaneous administration of the 2nd MMR and 4th DPT-P-Hib at 18 months of age was responsible for 46% of incompleteness. The following characteristics were significantly associated with an incomplete immunization status: being a single parent, > or = 2 children in the family, an older age at first immunization (> or = 3 months), parent's preference for postponing the second vaccine when two injections are scheduled for the same visit, perception of lack of information about vaccination, and disagreement with immunization recommendations. CONCLUSION: One of the key points of this study is the impact of the non-simultaneous administration of the two vaccines at 18 months. Factors such as being a single parent and older age at first immunization might be used to design an early intervention for children who are most likely to be incompletely immunized. Even if parents are favourable towards immunization, they need to be well informed about the associated risks and benefits.