Ultrasonic transducers based on curved lead-free piezoelectric thick films for high resolution medical imaging

International audienceKNN-based lead free ferroelectric materials are receiving much attention due to their high electromechanical properties that make them promising candidates to replace the lead-based piezoceramics that will eventually be banned by environmental regulations in many countries over the world. Studies include the development of KNN thick films that are particularly well adapted for high frequency applications due to higher wave velocities and a dielectric constant in an acceptable range for single element transducers. Here, a KNN based thick film is deposited on a curved substrate by pad-printing in order to be used in a focused high frequency transducer. This substrate is a porous lead-free KNN cylinder specifically developed to exhibit the required acoustical properties of a backing (acoustical impedance, high attenuation) and is compatible with the high sintering temperature of the KNN thick film. Electromechanical properties of the piezoelectric thick film in thickness mode were deduced (kt over 35%). This structure was used to fabricate a transducer which was characterized (relative bandwidth over 90%). Finally this transducer was integrated in a high frequency imaging system and its performance allowed skin images to be produced. To conclude, the replacement of lead-based high frequency transducers by green devices is a viable option

Non-Planar Pad-Printed Think-Film Focused High-Frequency Ultrasonic Transducers for Imaging and Therapeutic Applications

Pad-printed thick-film transducers have been shown to be an interesting alternative to lapped bulk piezoceramics, because the film is deposited with the required thickness, size, and geometry, thus avoiding any subsequent machining to achieve geometrical focusing. Their electromechanical properties are close to those of bulk ceramics with similar composition despite having a higher porosity. In this paper, padprinted high-frequency transducers based on a low-loss piezoceramic composition are designed and fabricated. High-porosity ceramic cylinders with a spherical top surface are used as the backing substrate. The transducers are characterized in view of imaging applications and their imaging capabilities are evaluated with phantoms containing spherical inclusions and in different biological tissues. In addition, the transducers are evaluated for their capability to produce high-acoustic intensities at frequencies around 20 MHz. High-intensity measurements, obtained with a calibrated hydrophone, show that transducer performance is promising for applications that would require the same device to be used for imaging and for therapy. Nevertheless, the transducer design can be improved, and simulation studies are performed to find a better compromise between low-power and high-power performance. The size, geometry, and constitutive materials of optimized configurations are proposed and their feasibility is discussed

Community participation for reproductive, maternal, newborn and child health: insights from the design and implementation of the BornFyne-prenatal management system digital platform in Cameroon

IntroductionAcross communities in low-middle income countries, digital health is currently revolutionizing the delivery of health services, particularly in the field of reproductive, maternal, newborn, and child health (RMNCH) services. While studies have shown the effectiveness of mHealth in delivering RMNCH services, there is little information about factors that enhance mHealth services utilization in low-cost settings including stakeholders’ level of influence on the implementation of digital health intervention in sub–Saharan Africa. This paper seeks to describe important lessons on the levels of stakeholders’ direct or indirect influence on the design and implementation of the BornFyne-PNMS digital health platform to support RMNCH services.MethodsA participatory research (PR) design approach was employed to explore stakeholders’ perspectives of a new initiative, through direct engagement of local priorities and perspectives. The process of introducing the digital application called the BornFyne-PNMS for district health delivery system and the community, and integrating it within the district health delivery system was guided by research-to-action, consistent with the PR approach. To explore stakeholders’ perspectives through a PR approach, we conducted a series of stakeholder meetings fashioned after focus group discussions.ResultsIssues around male involvement in the program, sensitization and equity concerns arose. Emergent challenges and proposed strategies for implementation from diverse stakeholders evidently enriched the design and implementation process of the project intervention. Stakeholder meetings informed the addition of variables on the mobile application that were otherwise initially omitted, which will further enhance the RMNCH electronic data collection for health information systems strengthening in Cameroon.DiscussionThis study charts a direction that is critical in digital health delivery of RMNCH in a rural and low-income community and describes the important iterative stakeholder input throughout the study. The strategy of stakeholders’ involvement in the BornFyne PNMS implementation charts a direction for ownership and sustainability in the strengthening of Cameroon's health information system

Projet pilote pour l'accès au dépistage et à la prise en charge du col de l'utérus dans le district de santé d'Akonolinga : Difficultés et perspectives

International audienceLe cancer du col de l'utérus est le 2 e cancer le plus fréquent chez la femme camerounaise, il est responsable d'environ 1120 décès par an. Ces chiffres pourraient être réduits grâce au dépistage systématique avec prise en charge appropriée des cas détectés. Il est donc nécessaire de proposer des stratégies alternatives à l'examen cytologique recommandé qui nécessite plusieurs consultations et qui est difficilement accessible au plan financier. OBJECTIFS Présenter la stratégie adoptée et les difficultés de mise en oeuvre d'un service innovant de dépistage et de prise en charge du cancer du col dans le district de santé d'Akonolinga. METHODOLOGIE Une salle de consultation gynécologique opérationnelle à Akonolinga depuis 21 mois (mars 2017 à novembre 2018), propose un dépistage du cancer du col aux femmes de 25 ans et plus (8495 femmes en âge de se faire dépister dans le district de santé) par inspection visuelle à l'acide acétique et au lugol (méthode recommandée par l'OMS pour les pays à ressources limitées). Les femmes dépistées négatives sont revues après 3 ans. En cas de positivité, une biopsie du col est réalisée et acheminée à Yaoundé pour histopathologie. Dans un 1 er temps la prise en charge reposait sur une surveillance semestrielle des dysplasies de bas grade faute de matériel pour la thermoablation, une résection des lésions à l'anse diathermique face à des dysplasies de haut grade et une hystérectomie pour les cancer-micro-invasifs. L'acquisition du WISAP en Octobre 2018 pour le traitement immédiat des lésions par thermoablation a permis d'améliorer la qualité du suivi des patientes par une approche « test and treat » pour les lésions VIA/VILI positives. Un triage par screening du HPV est prévu pour Juin 2019. Après 21 mois d'activité, 276 femmes âgées entre 25 et 55 ans se sont faites dépistées, soit 3% de la cible. Ce faible taux est lié à une sensibilisation communautaire insuffisante, au manque d'implication de certains personnels de santé du district, en plus de l'éloignement géographique de certaines populations. Des VIA/VILI réalisés, 27 % se sont avérés positifs. Néanmoins seul 53 % des analyses histopathologiques ont été réalisées car la subvention des frais d'examen dans leur totalité ne date que de Juillet 2018 (près de 50 % des femmes étaient sans-emploi). On recense 3 cas de cancers invasifs (1,1%), 2 de cancers micro-invasifs (0,7%), 20 cas de dysplasies cervicales confirmés dans la population dépistées soit 13,8 % (7 de haut grade et 13 de bas grade). A ce stade, seul 19 % des femmes dépistées positives ont été traitées car le « test and treat » n'étant effectif que depuis Octobre 2018, plusieurs patientes ont été perdues de vue malgré la relance de celles-ci par appel téléphonique. WISAP® Exemple de VIA Positives Exemple de VILI Positives Exemple de col après résection à l'anse diathermique Exemple de col après thermoablation 73% 27% PROPORTION DES DÉPISTAGES POSITIFS APRES INSPECTION VISUELLE (VIA/VILI) VIA/VILI néga-tifs VIA/VILI positifs 3% 97% PROPORTION DU DEPISTAGE DU CANCER DU COL DE L'UTERUS DANS LA VILLE D'AKONOLINGA ENTRE JANVIER 2017 ET NOVEMBRE 2018 pourcentage de femmes dépistées pourcentage de femmes non dépis-tées 19% 81% PROPORTION DES PATIENTES PRESENTANT UN VIA/VILI POSITIF AYANT ETE TRAITEES patientes traitées patientes non trai-tées CONCLUSION Malgré une stratégie innovante nous observons des difficultés dans la mise en oeuvre: le manque d'adhésion à la démarche du dépistage dû aux connaissances limitées de la pathologie, le coût financier de la prise en charge et la non disponibilité du plateau technique dans son entièreté durant les premiers mois d'activité. Néanmoins les résultats obtenus révèlent l'ampleur du problème dans cette communauté et témoigne de l'importance de l'action menée. La mise sur pied d'un plan de sensibilisation ciblé, l'implication d'un maximum d'acteurs de la santé, en plus de la subvention du coût de la prise en charge ainsi que l'acquisition de l'ensemble du matériel (déjà effectif), sont les mesures qui permettront d'atteindre l'objectif de prévention de la maladie

Snakebite epidemiology and health-seeking behavior in Akonolinga health district, Cameroon: Cross-sectional study.

BackgroundSnakebite envenoming causes 81,000-138,000 annual human deaths and pain, terror, or disability in 4.5-5.4 million victims. Accurate community-based epidemiological data is scarce. Our objective was to assess snakebite incidence, mortality, and health-seeking behavior, in an affected health district of Cameroon.MethodsWe conducted a cross-sectional multicluster household survey in Akonolinga health district, Centre Region, Cameroon, from October to December 2016. Using probability-proportional-to-size, 20 villages were randomly selected, then, all inhabited households were systematically selected. Annual incidence and adjusted odds-ratio for predictors were estimated.FindingsAmong the 9,924 participants, 66 suffered a snakebite during the past year: the resulting incidence is 665 (95%CI: 519-841) per 100,000 inhabitants per year. Victims were aged 5-75y (median: 34y), 53% were male and 57% farmer-cultivators. Two children died (case-fatality rate: 3%); 39 (59%) presented severity signs, including 2 (3%) neurotoxic syndromes, 20 (30%) systemic digestive syndromes, and 17 (26%) severe cytotoxic syndromes. Non-severe cases included 20 (30%) mild cytotoxic syndromes and 7 (11%) dry bites. Only two victims (3%) received antivenom. 59 (89%) used family traditional practices, 25 (38%) traditional healers, and 31 (47%) consulted health facilities. Median delays to these three care-options were 5, 45, and 60 minutes, respectively. Traditional treatments included incisions (n = 57; 86%), tourniquets (n = 51; 77%) and black-stones (n = 44; 67%). The two last procedures were also used in health facilities (n = 18). Consulting traditional healers was associated with severity (adjusted-OR: 19.6 (2.5-156), p = 0.005) and complications (aOR: 17.3, 2.4-123, p = 0.004). Long-term disabilities were subjective psychological trauma (n = 47; 71%), finger amputation (n = 1; 2%), ankylosis (n = 1; 2%) and chronic pain (n = 1; 2%).ConclusionsWe observed alarming levels of snakebite incidence, mortality, antivenom scarcity, and use of traditional medicine. It could represent several thousands of victims at national level. We suggested conducting a country-wide study, and improving antivenom supply, first-aid training, for traditional healers and health professionals

La Prévention des Incapacités dans la Prise en Charge Multidisciplinaire des Plaies et des Maladies Tropicales Négligées

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Plaies chroniques, Ulcère de Buruli et Tradipraticiens : conception d'une étude pour mieux comprendre les réalités du terrain dans le district de santé d'Akonolinga, région du centre Cameroun

International audienc

Plaies chroniques, Ulcère de Buruli et Tradipraticiens : conception d'une étude pour mieux comprendre les réalités du terrain dans le district de santé d'Akonolinga, région du centre Cameroun

International audienc

Clinical features and management of a severe paradoxical reaction associated with combined treatment of Buruli ulcer and HIV co-infection

In West and Central Africa Buruli ulcer (BU) and HIV co-infection is increasingly recognised and management of these two diseases combined is an emerging challenge for which there is little published information. In this case we present a severe paradoxical reaction occurring after commencing antibiotic treatment for BU combined with antiretroviral therapy for HIV, and describe its clinical features and management. This includes to our knowledge the first reported use of prednisolone in Africa to manage a severe paradoxical reaction related to BU treatment