36 research outputs found
Caractérisation multi-échelle et analyse par essai d'indentation instrumentée de matériaux à gradient générés par procédés mécaniques et thermochimiques de traitement de surface
Cette thÚse est un travail prospectif sur la caractérisation multi-échelle de matériaux à gradient de propriétés générés par des traitements de surface de type mécanique (grenaillage à air comprimé ou par ultrasons) ou thermochimique (nitruration, implantation ionique, cémentation basse température). Les apports de plusieurs techniques de caractérisation (microscopie électronique à balayage, spectrométrie, indentation instrumentée, microscopie interférométrique), à différentes échelles, et l existence possible d une signature des traitements de surface étudiés sur le matériau ont été examinés. Une analyse multi-échelle des échantillons grenaillés par ultrasons a permis d établir un lien entre les paramÚtres procédé et la rugosité du matériau. Une approche originale statistique a été proposée pour déterminer la dureté d un matériau modifié par un traitement de surface donné sans altérer la surface par une rectification. Elle a permis d établir un lien entre la rugosité des échantillons grenaillés par ultrasons et leur dureté. Une recherche bibliographique détaillée a été réalisée sur la simulation de l essai d indentation instrumentée par éléments finis en étudiant une centaine d articles afin d évaluer l influence des hypothÚses des modÚles sur leurs résultats. A l aide d un modÚle éléments finis, la sensibilité des courbes d indentation à une variation des paramÚtres matériau a été examinée. Cela a permis de mettre en place une réflexion sur l identification des propriétés d un matériau à gradient à l aide de l essai d indentation.This thesis is a prospective work on the multiscale characterization of plastically graded materials obtained with mechanical (shot peening using air pressure or ultrasounds) or thermochemical (nitriding, ion implantation, low temperature carburizing) surface treatments. The benefits of several characterization techniques (scanning electron microscopy, spectrometry, instrumented indentation, interferometric microscopy), at different scales, and the possible existence of a signature of the studied surface treatments on the material were examined. A multiscale analysis of the ultrasonically shot-peened specimens linked the process conditions with the material roughness. A novel statistical approach was proposed to determine the treated material roughness without deteriorating the surface through resurfacing. The latter enabled to establish a link between the shot-peened specimen roughness and their hardness. A detailed literature review of a hundred articles examined the IV simulation of the instrumented indentation test with finite elements in order to assess the effect of different hypotheses on the simulation results. Using a finite element model, the sensitivity of indentation curves to a variation of material parameters was examined. The latter enabled to reflect on the identification of the properties of plastically grade materials using the instrumented indentation test.COMPIEGNE-BU (601592101) / SudocSudocFranceF
The effect of stress and anxiety associated with maternal prenatal diagnosis on feto-maternal attachment
<p>Abstract</p> <p>Background</p> <p>A couple's decision to undergo an invasive test based on a screening test result is a process associated with anxiety. The aim of this study was to determine whether anxiety and prenatal attachment were affected by undergoing an invasive test compared to women in early pregnancy and after a reassuring anomaly scan.</p> <p>Methods</p> <p>200 women were recruited at booking, 14 women and 20 partners after an invasive test and 81 women following an anomaly scan. A questionnaire was completed using the Beck Anxiety Inventory and Maternal or Paternal Antenatal Attachment Scales.</p> <p>Results</p> <p>Women who have had an invasive test have higher levels of anxiety compared to women at booking (P < 0.01) and after an anomaly scan (P = 0.002). Anxiety declines from booking to the time of an anomaly scan (P = 0.025), whilst attachment increases (P < 0.001). There is a positive correlation between anxiety and attachment in women who have had an invasive test (r = 0.479). Partners of women undergoing an invasive test experience lower levels of anxiety (P < 0.05).</p> <p>Conclusions</p> <p>Women undergoing prenatal diagnostic procedures experience more psychological distress, which may be currently underestimated. Establishment of interdisciplinary treatment settings where access to psychological support is facilitated may be beneficial.</p
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Effect of personalized nutrition on health-related behaviour change: evidence from the Food4me European randomized controlled trial
Background: Optimal nutritional choices are linked with better health, but many current interventions to improve diet have limited effect. We tested the hypothesis that providing personalized nutrition (PN) advice based on information on individual diet and lifestyle,
phenotype and/or genotype would promote larger, more appropriate, and sustained changes in dietary behaviour.
Methods: Adults from seven European countries were recruited to an internet-delivered intervention (Food4Me) and randomized to: (i) conventional dietary advice (control) or to PN advice based on: (ii) individual baseline diet; (iii) individual baseline diet plus
phenotype (anthropometry and blood biomarkers); or (iv) individual baseline diet plus phenotype plus genotype (five diet-responsive genetic variants). Outcomes were
dietary intake, anthropometry and blood biomarkers measured at baseline and after 3 and 6 monthsâ intervention.
Results: At baseline, mean age of participants was 39.8 years (range 18â79), 59% of participants were female and mean body mass index (BMI) was 25.5 kg/m2. From the
enrolled participants, 1269 completed the study. Following a 6-month intervention, participants randomized to PN consumed less red meat [-5.48 g, (95% confidence interval:-
10.8,-0.09), P=0.046], salt [-0.65 g, (-1.1,-0.25), P=0.002] and saturated fat [-1.14 % of energy, (-1.6,-0.67), P<0.0001], increased folate [29.6 mg, (0.21,59.0), P=0.048] intake and had higher Healthy Eating Index scores [1.27, (0.30, 2.25), P=0.010) than those randomized to the control arm. There was no evidence that including phenotypic and phenotypic plus genotypic information enhanced the effectiveness of the PN advice.
Conclusions: Among European adults, PN advice via internet-delivered intervention produced larger and more appropriate changes in dietary behaviour than a conventional approach
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The effect of the apolipoprotein E genotype on response to personalized dietary advice intervention: findings from the Food4Me randomized controlled trial
Background: The apolipoprotein E (APOE) risk allele (É4) is associated with higher total cholesterol (TC), amplified response to saturated fatty acid (SFA) reduction, and increased cardiovascular disease. Although knowledge of gene risk may enhance dietary change, it is unclear whether É4 carriers would benefit from gene-based personalized nutrition (PN).
Objectives: The aims of this study were to 1) investigate interactions between APOE genotype and habitual dietary fat intake and modulations of fat intake on metabolic outcomes; 2) determine whether gene-based PN results in greater dietary change than do standard dietary advice (level 0) and nongene-based PN (levels 1â2); and 3) assess the impact of knowledge of APOE risk (risk: E4+, nonrisk: E4â) on dietary change after gene-based PN (level 3).
Design: Individuals (n = 1466) recruited into the Food4Me pan-European PN dietary intervention study were randomly assigned to 4 treatment arms and genotyped for APOE (rs429358 and rs7412). Diet and dried blood spot TC and Ï-3 (nâ3) index were determined at baseline and after a 6-mo intervention. Data were analyzed with the use of adjusted general linear models.
Results: Significantly higher TC concentrations were observed in E4+ participants than in E4â (P < 0.05). Although there were no significant differences in APOE response to gene-based PN (E4+ compared with E4â), both groups had a greater reduction in SFA (percentage of total energy) intake than at level 0 (mean ± SD: E4+, â0.72% ± 0.35% compared with â1.95% ± 0.45%, P = 0.035; E4â, â0.31% ± 0.20% compared with â1.68% ± 0.35%, P = 0.029). Gene-based PN was associated with a smaller reduction in SFA intake than in nongene-based PN (level 2) for E4â participants (â1.68% ± 0.35% compared with â2.56% ± 0.27%, P = 0.025).
Conclusions: The APOE É4 allele was associated with higher TC. Although gene-based PN targeted to APOE was more effective in reducing SFA intake than standard dietary advice, there was no difference between APOE âriskâ and ânonriskâ groups. Furthermore, disclosure of APOE nonrisk may have weakened dietary response to PN
Caractérisation multi-échelle et analyse par essai d'indentation instrumentée de matériaux à gradient générés par procédés mécaniques et thermochimiques de traitement de surface
This thesis is a prospective work on the multiscale characterization of plastically graded materials obtained with mechanical (shot peening using air pressure or ultrasounds) or thermochemical (nitriding, ion implantation, low temperature carburizing) surface treatments. The benefits of several characterization techniques (scanning electron microscopy, spectrometry, instrumented indentation, interferometric microscopy), at different scales, and the possible existence of a signature of the studied surface treatments on the material were examined. A multiscale analysis of the ultrasonically shot-peened specimens linked the process conditions with the material roughness. A novel statistical approach was proposed to determine the treated material roughness without deteriorating the surface through resurfacing. The latter enabled to establish a link between the shot-peened specimen roughness and their hardness. A detailed literature review of a hundred articles examined the IV simulation of the instrumented indentation test with finite elements in order to assess the effect of different hypotheses on the simulation results. Using a finite element model, the sensitivity of indentation curves to a variation of material parameters was examined. The latter enabled to reflect on the identification of the properties of plastically grade materials using the instrumented indentation test.Cette thĂšse est un travail prospectif sur la caractĂ©risation multi-Ă©chelle de matĂ©riaux Ă gradient de propriĂ©tĂ©s gĂ©nĂ©rĂ©s par des traitements de surface de type mĂ©canique (grenaillage Ă air comprimĂ© ou par ultrasons) ou thermochimique (nitruration, implantation ionique, cĂ©mentation basse tempĂ©rature). Les apports de plusieurs techniques de caractĂ©risation (microscopie Ă©lectronique Ă balayage, spectromĂ©trie, indentation instrumentĂ©e, microscopie interfĂ©romĂ©trique), Ă diffĂ©rentes Ă©chelles, et lâexistence possible dâune signature des traitements de surface Ă©tudiĂ©s sur le matĂ©riau ont Ă©tĂ© examinĂ©s. Une analyse multi-Ă©chelle des Ă©chantillons grenaillĂ©s par ultrasons a permis dâĂ©tablir un lien entre les paramĂštres procĂ©dĂ© et la rugositĂ© du matĂ©riau. Une approche originale statistique a Ă©tĂ© proposĂ©e pour dĂ©terminer la duretĂ© dâun matĂ©riau modifiĂ© par un traitement de surface donnĂ© sans altĂ©rer la surface par une rectification. Elle a permis dâĂ©tablir un lien entre la rugositĂ© des Ă©chantillons grenaillĂ©s par ultrasons et leur duretĂ©. Une recherche bibliographique dĂ©taillĂ©e a Ă©tĂ© rĂ©alisĂ©e sur la simulation de lâessai dâindentation instrumentĂ©e par Ă©lĂ©ments finis en Ă©tudiant une centaine dâarticles afin dâĂ©valuer lâinfluence des hypothĂšses des modĂšles sur leurs rĂ©sultats. A lâaide dâun modĂšle Ă©lĂ©ments finis, la sensibilitĂ© des courbes dâindentation Ă une variation des paramĂštres matĂ©riau a Ă©tĂ© examinĂ©e. Cela a permis de mettre en place une rĂ©flexion sur lâidentification des propriĂ©tĂ©s dâun matĂ©riau Ă gradient Ă lâaide de lâessai dâindentation
Multiscale characterization and analysis through the use of instrumented indentation of plastically graded materials obtained with thermochemical and mechanical surface treatments
Cette thĂšse est un travail prospectif sur la caractĂ©risation multi-Ă©chelle de matĂ©riaux Ă gradient de propriĂ©tĂ©s gĂ©nĂ©rĂ©s par des traitements de surface de type mĂ©canique (grenaillage Ă air comprimĂ© ou par ultrasons) ou thermochimique (nitruration, implantation ionique, cĂ©mentation basse tempĂ©rature). Les apports de plusieurs techniques de caractĂ©risation (microscopie Ă©lectronique Ă balayage, spectromĂ©trie, indentation instrumentĂ©e, microscopie interfĂ©romĂ©trique), Ă diffĂ©rentes Ă©chelles, et lâexistence possible dâune signature des traitements de surface Ă©tudiĂ©s sur le matĂ©riau ont Ă©tĂ© examinĂ©s. Une analyse multi-Ă©chelle des Ă©chantillons grenaillĂ©s par ultrasons a permis dâĂ©tablir un lien entre les paramĂštres procĂ©dĂ© et la rugositĂ© du matĂ©riau. Une approche originale statistique a Ă©tĂ© proposĂ©e pour dĂ©terminer la duretĂ© dâun matĂ©riau modifiĂ© par un traitement de surface donnĂ© sans altĂ©rer la surface par une rectification. Elle a permis dâĂ©tablir un lien entre la rugositĂ© des Ă©chantillons grenaillĂ©s par ultrasons et leur duretĂ©. Une recherche bibliographique dĂ©taillĂ©e a Ă©tĂ© rĂ©alisĂ©e sur la simulation de lâessai dâindentation instrumentĂ©e par Ă©lĂ©ments finis en Ă©tudiant une centaine dâarticles afin dâĂ©valuer lâinfluence des hypothĂšses des modĂšles sur leurs rĂ©sultats. A lâaide dâun modĂšle Ă©lĂ©ments finis, la sensibilitĂ© des courbes dâindentation Ă une variation des paramĂštres matĂ©riau a Ă©tĂ© examinĂ©e. Cela a permis de mettre en place une rĂ©flexion sur lâidentification des propriĂ©tĂ©s dâun matĂ©riau Ă gradient Ă lâaide de lâessai dâindentation.This thesis is a prospective work on the multiscale characterization of plastically graded materials obtained with mechanical (shot peening using air pressure or ultrasounds) or thermochemical (nitriding, ion implantation, low temperature carburizing) surface treatments. The benefits of several characterization techniques (scanning electron microscopy, spectrometry, instrumented indentation, interferometric microscopy), at different scales, and the possible existence of a signature of the studied surface treatments on the material were examined. A multiscale analysis of the ultrasonically shot-peened specimens linked the process conditions with the material roughness. A novel statistical approach was proposed to determine the treated material roughness without deteriorating the surface through resurfacing. The latter enabled to establish a link between the shot-peened specimen roughness and their hardness. A detailed literature review of a hundred articles examined the IV simulation of the instrumented indentation test with finite elements in order to assess the effect of different hypotheses on the simulation results. Using a finite element model, the sensitivity of indentation curves to a variation of material parameters was examined. The latter enabled to reflect on the identification of the properties of plastically grade materials using the instrumented indentation test
Implantologie et diabĂšte de type 1
Le diabĂšte sucrĂ© a longtemps Ă©tĂ© considĂ©rĂ© comme une contre-indication relative Ă l'implantologie. Compte tenu de la place croissante de l'implantologie en chirurgie dentaire et de l'augmentation de la prĂ©valence du diabĂšte, la confrontation de cette technique chez ce type de patients est de plus en plus frĂ©quente. De nombreuses Ă©tudes se sont intĂ©ressĂ©es ces derniĂšres annĂ©es au diabĂšte de type 2 mais bien moins au diabĂšte de type 1. Nous avons voulu faire un point actuel de la littĂ©rature sur l'implantologie et le diabĂšte de type 1, pour montrer en quoi le diabĂšte de type 1 peut ĂȘtre un obstacle Ă l'ostĂ©ointĂ©gration, afin de mettre en avant les critĂšres d'Ă©ligibilitĂ© du patient diabĂštique de type 1 pouvant recevoir un implant.Prognostic of implantology has long been considered as disadvantaged in case of diabetes mellitus. Considering both increasing prevalence of diabetes mellitus and the increasing place of implantology in dentistry, this type of surgery is performed more frequently in such patients than previously. Clinical autcome of implantology is well known in case of type 2, alternatively to type 1 diabetes mellitus. International literature concerning implantology and type 1 diabetes mellitus was reviewed. The aim of this review was to study if type 1 diabetes mellitus could negatively influence osseointegration prognostic. We also tried to point putative selection criteria of type 1 diabetic patients related to favorable outcome of this procedure.BORDEAUX2-BU Sci.Homme/Odontol. (330632102) / SudocSudocFranceF
Microlithography Technique Advantages, Limits and Its Coupling with EBSD Measurements
International audienc