98 research outputs found

    Microstructural modifications in α-brass targets after small charge explosions

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    Metals exposed to explosions undergo several macro and micro changes. At the microstructural level slip bands or mechanical twins, caused by the pressure and temperature wave, can be detected. Twinning or slip occurs depending on the metal stacking fault energy, the blast wave pressure and the deformation rate. An experimental campaign was performed on different FCC metals. Results concerning α-brass (30% Zn) are presented herein. Specimens exposed to small charge explosion (100 g of plastic explosive) were analyzed by optical and electronic microscopy, by Electron Back-Scattered Diffraction (EBSD) imaging, and by X-ray diffraction. Microstructural plastic deformation marks were detected and their possible attribution, either to mechanical twinning or to cross slip, is discussed on the basis of X-ray diffraction and EBSD results. The detectability target-to-charge distance limit, and hence the critical stress for microstructural changes, are evaluated

    Evolution of intermetallics, dispersoids and elevated-temperature properties at various Fe contents in Al-Mn-Mg 3004 alloys

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    Nowadays, great interests are rising on aluminum alloys for the applications at elevated temperature, driven by the automotive and aerospace industries requiring high strength, light weight and low cost engineering materials. As one of the most promising candidates, Al-Mn-Mg 3004 alloys have been found to possess considerably high mechanical properties and creep resistance at elevated temperature resulted from the precipitation of a large number of thermally stable dispersoids during heat treatment. In present work, the effect of Fe contents on the evolution of microstructure as well as high temperature properties of 3004 alloys has been investigated. Results show that the dominant intermetallic changes from α-Al(MnFe)Si at 0.1 wt. % Fe to Al6(MnFe) at both 0.3 and 0.6 wt. % Fe. In the Fe range of 0.1 to 0.6 wt. % studied, a significant improvement on mechanical properties at elevated temperature has been observed due to the precipitation of dispersoids, and the best combination of yield strength and creep resistance at 573K (300°C) is obtained in the 0.3% Fe alloy with finest size and highest volume fraction of dispersoids. The superior properties obtained at 573K (300°C) makes 3004 alloys more promising for high temperature applications. The relationship between the Fe content and the dispersoid precipitation as well as the materials properties has been discussed

    Are psychiatrists trained to address the mental health needs of young people transitioning from child to adult services? Insights from a European survey

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    Background: In mental health, transition refers to the pathway of young people from child and adolescent to adult services. Training of mental health psychiatrists on transition-related topics offers the opportunity to improve clinical practice and experiences of young people reaching the upper age limit of child and adolescent care. Methods: National psychiatrist's organizations or experts from 21 European countries were surveyed 1/ to describe the status of transition in adult psychiatry (AP) and child and adolescent psychiatry (CAP) postgraduate training in Europe; 2/ to explore the amount of cross-training between both specialties. This survey was a part of the MILESTONE project aiming to study and improve the transition process of young people at the service boundary. Results: Transition was a mandatory topic in the AP curriculum of 1/19 countries (5%) and in the CAP curriculum of 4/17 countries (24%). Most topics relevant for transition planning were addressed during AP training in 7/17 countries (41%) to 10/17 countries (59%), and during CAP training in 9/11 countries (82%) to 13/13 countries (100%). Depending on the training models, theoretical education in CAP was mandatory during AP training in 94% (15/16) to 100% of the countries (3/3); and in AP during CAP training in 81% (13/16) to 100% of the countries (3/3). Placements were mandatory in CAP during AP training in 67% (2/3) to 71% of the countries (12/17); and in AP during CAP training in 87% (13/15) to 100% of the countries (3/3). Discussion and Conclusion: Specific training about transition is limited during CAP and AP postgraduate training in Europe. Cross-training between both specialties offers a basis for improved communication between child and adult services but efforts should be sustained in practical training. Recommendations are provided to foster further development and meet the specific needs of young people transitioning to adult services

    The importance of clinicians' and parents' awareness of suicidal behaviour in adolescents reaching the upper age limit of their mental health services in Europe

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    Background: To study clinicians' and parents' awareness of suicidal behaviour in adolescents reaching the upper age limit of their Child and Adolescent Mental Health Service (CAMHS) and its association with mental health indicators, transition recommendations and mental health service (MHS) use. Methods: 763 CAMHS users from eight European countries were assessed using multi-informant and standardised assessment tools at baseline and nine months follow-up. Separate ANCOVA's and pairwise comparisons were conducted to assess whether clinicians' and parents' awareness of young people's suicidal behaviour were associated with mental health indicators, clinician's recommendations to continue treatment and MHS use at nine months follow-up. Results: 53.5 % of clinicians and 56.9 % of parents were unaware of young people's self-reported suicidal behaviour at baseline. Compared to those whose clinicians/parents were aware, unawareness was associated with a 72–80 % lower proportion of being recommended to continue treatment. Self-reported mental health problems at baseline were comparable for young people whose clinicians and parents were aware and unaware of suicidal behaviour. Clinicians' and parents' unawareness were not associated with MHS use at follow-up. Limitations: Aspects of suicidal behaviour, such as suicide ideation, -plans and -attempts, could not be distinguished. Few young people transitioned to Adult Mental Health Services (AMHS), therefore power to study factors associated with AMHS use was limited. Conclusion: Clinicians and parents are often unaware of suicidal behaviour, which decreases the likelihood of a recommendation to continue treatment, but does not seem to affect young people's MHS use or their mental health problems

    Associations of common breast cancer susceptibility alleles with risk of breast cancer subtypes in BRCA1 and BRCA2 mutation carriers

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    Introduction: More than 70 common alleles are known to be involved in breast cancer (BC) susceptibility, and several exhibit significant heterogeneity in their associations with different BC subtypes. Although there are differences in the association patterns between BRCA1 and BRCA2 mutation carriers and the general population for several loci, no study has comprehensively evaluated the associations of all known BC susceptibility alleles with risk of BC subtypes in BRCA1 and BRCA2 carriers. Methods: We used data from 15,252 BRCA1 and 8,211 BRCA2 carriers to analyze the associations between approximately 200,000 genetic variants on the iCOGS array and risk of BC subtypes defined by estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and triple-negative- (TN) status; morphologic subtypes; histological grade; and nodal involvement. Results: The estimated BC hazard ratios (HRs) for the 74 known BC alleles in BRCA1 carriers exhibited moderate correlations with the corresponding odds ratios from the general population. However, their associations with ER-positive BC in BRCA1 carriers were more consistent with the ER-positive as

    Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus

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    A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk
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