Modélisation numérique des antennes d'acquisition du signal image en IRM pendant la relaxation

Une technique numérique basée sur le couplage d une approximation par éléments finis et d une méthode intégrale a été développée pour le calcul du signal induit dans les antennes I.R.M. Ce signal est issu du mouvement de précession libre de l aimantation transversale du corps à explorer pendant la relaxation. Dans notre modélisation, l aimantation transversale représente le champ magnétique source. Celui-ci induit dans l antenne un courant d une durée très brève (quelques millisecondes) ; il représente le signal contenant toutes les informations de l échantillon. Notre modélisation des antennes d I.R.M de type circuit imprimé a été validée par comparaison avec des mesures expérimentales ainsi qu avec une méthode analytique. Nous l avons développée en tenant compte de leurs géométries et de leurs caractéristiques électromagnétiques afin d avoir un meilleur rapport Signal/Bruit. Nous avons pris en considération des principaux facteurs tels que la distance entre l antenne et l échantillon à explorer ainsi que les caractéristiques électromagnétiques de l antenne.A numerical technique, based on the combination of a finite element method and a boundary integral method, has been developed to compute the induced signal in MRI antennas. This signal rises from a free movement of precession of the transverse magnetization of the sample to explore. In our modeling, the transverse magnetization represents the magnetic source field. Its flux embraces the antenna to give rise to a sinusoidal current which is very quickly attenuated in time (a few ms); it represents the signal containing all the information of the sample. We here want to find the geometrical and electromagnetic characteristics of the antennas which permit to have a signal to noise ratio as great as possible. In our computation, we have taken into account leading factors such as the distance between the probe and the organ to be explored and also the geometrical and electromagnetic characteristics of the probe. Our modeling of printed circuits MRI antenna has been validated by comparing with experimental measurements and also with an anlytical method. We have developped it by taking into account their geometries and their electromagnetical characteristics in order to have a better signal/noise ratio. We have considered principal factors such as the distance between the antenna and the organ to explore and also the electromagnetic characteristics of the antenna.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

At the heart of the problem - A person-centred, developmental perspective on the link between alcohol consumption and cardio-vascular events.

INTRODUCTION: The cardio-protective effect of alcohol has been the subject of a long-standing scientific controversy. Emerging evidence remains equivocal, as the validity of the dose-dependent J-shape association is tainted by conceptual, theoretical and methodological problems. A major impediment for a resolution on the matter is the lack of a life-long developmental approach to pinpoint alcohol's specific impact on the risk for cardio-vascular events (CVE). OBJECTIVE: Using retrospective and prospective individual-level data of alcohol consumption (AC) we applied a model-based clustering technique to uncover life-course trajectories of AC and explored their links to CVE. METHODS: Data stemmed from a random sub-cohort of a large-scale, longitudinal study conducted in the Netherlands (N=2288). Group Based Trajectory Model (GBTM) was applied to extract distinct progressions of AC over time. Stratified by sex, the association between the developmental trajectories and CVE was examined with multiple logistic regression models, with adjustment for traditional risk factors. RESULTS: GBTM analysis laid bare the heterogeneity of AC dynamics over the life-course, reiterating sex differences in drinking habits and CVE risk. AC temporal behaviors during adolescence and adulthood were diverse, but showed relative stability in in middle-age and elderly years. For males, adjusted odds for CVE differed among the uncovered developmental classes. CONCLUSIONS: The findings elicited supportive evidence for a J-shape, but with a new twist. Besides moderation the results indicate that onset, timing, duration and stability of AC over the life-course are major aspects to be accounted for when attempting to elucidate alcohol's cardio-vascular role

Improving alcohol screening and brief intervention delivery in general practices: an investigation of current practice, barriers and solutions

Reducing excessive and problematic alcohol consumption is one of the biggest challenges for public health due to the damaging effects of alcohol on both physical and mental health. Given that a large proportion of the general population has a general practitioner, GP practices are extremely well-suited to conducting alcohol screening tests and short-term interventions (ASKI). However, research has shown that alcohol use is rarely discussed and that alcohol abuse is rarely registered by GP offices. This despite the fact that many patients are perfectly comfortable discussing their alcohol use. The deployment of mental health assistants does not appear to increase the number of registrations. An implementation programme aimed at increasing knowledge, motivation and support among GPs has the potential to improve alcohol screenings and short-term interventions, but further research is necessary, given how complex and challenging it is to implement ASKI in GP offices

How Do Health and Social Networks Compare between Low-Income Multiproblem Households and the General Population?

Multiproblem households that receive social care for multiple problems, such as debts, psychiatric disorders, and domestic violence, may also be disadvantaged in terms of health and social networks. This study examines whether low-income multiproblem households and the general population differ in self-perceived health, mental health, health behaviors, and social networks. We performed a cross-sectional survey among respondents from low-income multiproblem households (n = 105) and the general population (n = 99) in the municipality of Apeldoorn in the Netherlands. Comparisons with national statistics data indicated that our sample of multiproblem households is more disadvantaged in terms of self-perceived health and mental health than low socioeconomic groups in general in the Netherlands. A multiple logistic regression analysis showed that being part of the multiproblem household group versus the general population group was associated with a lower educational level, a lower likelihood of being in paid employment, a lower score with respect to mental health, less alcohol consumption, and less fruit consumption. There were also differences between the groups on other variables, but these were not significant in adjusted analyses. In conclusion, multiproblem households in Apeldoorn had lower scores on mental health, drank fewer alcoholic drinks per week, and ate less fruit than the general population

Addressing Patients’ Alcohol Consumption–A Population-Based Survey of Patient Experiences

Objectives: To identify the proportion of the population that had experienced that alcohol was addressed in health care the previous year, to explore experiences and perceived effects of addressing alcohol, and to investigate the proportion of risky drinkers in the population. Methods: Cross-sectional national web-based survey with 1,208 participants. Socio-demographic data, alcohol consumption (AUDIT-C), and experiences with alcohol conversations were investigated. Results: Approximately four in five respondents had visited health care the past 12 months, and one in six reported having experienced addressing alcohol. Women and older respondents were less likely to report having experienced alcohol conversations compared to other groups. Risky drinkers were not more likely to have experienced an alcohol conversation, but reported longer duration of alcohol conversations and more frequently perceived addressing alcohol as awkward or judgmental. Almost a third of respondents were classified as risky drinkers. Conclusion: The proportion experiencing addressing alcohol in routine health care is low, also among risky drinkers, and risky drinkers more frequently experienced the conversations as judgmental. More sensitive and relevant ways of addressing alcohol in health care is needed.publishedVersio

Conversations about alcohol in healthcare : cross-sectional surveys in the Netherlands and Sweden

Background This study evaluated and compared the extent, duration, contents, experiences and effects of alcohol conversations in healthcare in the Netherlands and Sweden in 2017. Methods Survey data in the Netherlands and Sweden were collected through an online web panel. Subjects were 2996 participants (response rate: 50.8%) in Sweden and 2173 (response rate: 82.2%) in the Netherlands. Data was collected on socio-demographics, alcohol consumption, healthcare visits in the past 12 months, number of alcohol conversations, and characteristics of alcohol conversations (duration, contents, experience, effects). Results Results showed that Swedish respondents were more likely to have had alcohol conversations (OR = 1.99; 95%CI = 1.64–2.41; p = &lt; 0.001) compared to Dutch respondents. In Sweden, alcohol conversations were more often perceived as routine (p = &lt; 0.001), were longer (p = &lt; 0.001), and more often contained verbal information about alcohol’s health effects (p = 0.007) or written information (p = 0.001) than in the Netherlands. In Sweden, 40+ year-olds were less likely to report a positive effect compared to the youngest respondents. In the Netherlands, men, sick-listed respondents, and risky drinkers, and in Sweden those that reported “other” occupational status such as parental leave, were more likely to have had alcohol conversations. Conclusions The results suggest that alcohol conversations are more common in healthcare practice in Sweden than in the Netherlands. However, positive effects of alcohol conversations were less likely to be reported among older respondents in Sweden. Our results indicate that alcohol preventative work should be improved in both countries, with more focus on risky drinkers and the content of the conversations in Sweden, and expanding alcohol screening in the Netherlands.Funding Agencies|Linkoping University</p