Université de Bretagne Occidentale
Recent publications
Diabetic Retinopathy (DR), a prevalent and severe complication of diabetes, affects millions of individuals globally, underscoring the need for accurate and timely diagnosis. Recent advancements in imaging technologies, such as Ultra-WideField Color Fundus Photography (UWF-CFP) imaging and Optical Coherence Tomography Angiography (OCTA), provide opportunities for the early detection of DR but also pose significant challenges given the disparate nature of the data they produce. This study introduces a novel multimodal approach that leverages these imaging modalities to notably enhance DR classification. Our approach integrates 2D UWF-CFP images and 3D high-resolution 6\(\,\times \,\)6 mm\(^3\) OCTA (both structure and flow) images using a fusion of ResNet50 and 3D-ResNet50 models, with Squeeze-and-Excitation (SE) blocks to amplify relevant features. Additionally, to increase the model’s generalization capabilities, a multimodal extension of Manifold Mixup, applied to concatenated multimodal features, is implemented. Experimental results demonstrate a remarkable enhancement in DR classification performance with the proposed multimodal approach compared to methods relying on a single modality only. The methodology laid out in this work holds substantial promise for facilitating more accurate, early detection of DR, potentially improving clinical outcomes for patients.
Mesoscale eddies play an important role in transporting water properties, enhancing air-sea interactions, and promoting large-scale mixing of the ocean. They are generally referred to as “coherent” structures because they are organized, rotating fluid elements that propagate within the ocean and have long lifetimes (months or even years). Eddies have been sampled by sparse in-situ vertical profiles, but because in-situ ocean observations are limited, they have been characterized primarily from satellite observations, numerical simulations, or relatively idealized geophysical fluid dynamics methods. However, each of these approaches has its limitations. Many questions about the general structure and “coherence” of ocean eddies remain unanswered. In this study, we investigate the properties of 7 mesoscale eddies sampled with relative accuracy during 4 different field experiments in the Atlantic. Our results suggest that the Ertel Potential Vorticity (EPV) is a suitable parameter to isolate and characterize the eddy cores and their boundaries. The latter appear as regions of finite horizontal extent, characterized by a local extremum of the vertical and horizontal components of the EPV. These are found to be closely related to the presence of a different water mass in the core (relative to the background) and the steepening of the isopycnals due to eddy occurrence and dynamics. Based on these results, we propose a new criterion for defining eddies. We test our approach using a theoretical framework and explore the possible magnitude of this new criterion, including its upper bound.
Spectral computed tomography (CT) has recently emerged as an advanced version of medical CT and significantly improves conventional (single-energy) CT. Spectral CT has two main forms: dual-energy computed tomography (DECT) and photon-counting computed tomography (PCCT), which offer image improvement, material decomposition, and feature quantification relative to conventional CT. However, the inherent challenges of spectral CT, evidenced by data and image artifacts, remain a bottleneck for clinical applications. To address these problems, machine learning techniques have been widely applied to spectral CT. In this review, we present the state-of-the-art data-driven techniques for spectral CT.
Objective: The lipemia index (L-index), which reflects the turbidity of the sample, has been shown to be clinically relevant in the detection of severe hypertriglyceridemia and glycerol kinase deficiency . In addition, previously published evidence has raised interest in whether L-indexes could be used to identify patients with monoclonal gammopathy. Therefore, we aimed to determine the diagnostic accuracy of the lipemia index for the detection of monoclonal immunoglobulins (M-proteins). Methods: We reviewed all paired measurements of serum protein electrophoresis, serum and plasma L-index tests corresponding between 1 March 2022 and 13 July 2022 at the University Hospital of Brest, France. Sensitivity, specificity, positive predictive value and negative predictive value for the detection of M-protein were evaluated. Results: A total of 3795 patients were included in the study, of whom 457 (12%) were diagnosed with monoclonal gammopathy (Table 1). We found that the lipemia index had a good specificity of 99.8% (CI: 99.6–99.9) and 99.7% (CI: 99.6–99.9), but a low sensitivity of 7.7% (CI: 6.8–8.5) and 3.1% (CI 2.5–3.6) for the detection of M-proteins in serum and plasma samples, respectively (Table 2). The accuracy of the L-index differed clearly between M protein isotypes. The best sensitivity was observed for IgM in serum samples (21.4%; CI: 20.1–22.7). Conclusion: Increasing the L-index values on the Atellica CH 930 analyser was found to be specific but not sensitive for the detection of IgM M-proteins. Therefore, this relatively inexpensive and readily available test is a potential tool for the identification of M-proteins
Purpose Elite athletes are continually subjected to a range of constraints specific to high performance, and these can have a negative impact on their health. Although many studies have explored the individual factors related to risky behaviors and disorders in elite sport contexts, and have provided prevention programs, few have focused on health promotion. Consequently, the interpersonal, institutional, and policy factors of the health-related behaviors of elite athletes are still poorly explored. Based on the socioecological model of health, this study aimed to identify the factors involved in the health-related lifestyle of elite athletes. Methods Semi-structured interviews were conducted with 45 participants: athletes (N = 32; Mage=20.1, SD = 4.4), their coaches (N = 6; Mage=45.3, SD = 6.4) and managers of elite sport centers (N = 7; Mage=52.0, SD = 7.0). Interviews were audio recorded and transcribed verbatim. Both deductive and inductive thematic analyses were performed. This study was approved by the local Ethic Committee of the University. Results Our results highlight the different levels of factors related to the health-related lifestyle of elite athletes, using the socioecological model, as perceived by athletes themselves, coaches, and managers. Regarding intrapersonal factors, resilience qualities and health literacy appeared as key factors to influencing the health-related lifestyle of elite athletes. At the interpersonal level, parents and coaches were considered as the main sources of educational support. Regarding institutional factors, the health policies of the elite sport centers were key factors in supporting the athletes’ healthy lifestyle. Similarities and specificities of the views of the different actors have been identified. Conclusion These results show the interest of the application of the socioecological model in the elite sport domain. They encourage the development of health-promotion programs at different levels of intervention of the socioecological model, beyond traditional health prevention programs. In addition, this study suggests to consider the different perspectives of each actor to co-construct health promotion programs.
Abstract: Research on alcohol warnings has increased in the last decade, providing key evidence to governments on warning format and content. The bulk of this research, however, has been conducted in Anglosphere countries, whereas fewer studies have focused on other countries which have high per-capita alcohol consumption, and where the high social acceptability of drinking is liable to affect how people accept and react to prevention measures. We therefore explore how Young adults in France react to warnings on alcoholic beverage ads, as France has one of the highest per-capita alcohol consumption rates in the world according to the World Health Organization (WHO). We conducted 25 in-depth interviews with 18–25-year-old drinkers in France in 2017. Respondents were asked open-ended questions on the perceived impact of various warning contents (i.e., on health risk, social-cost risk, and on short vs long-term risk) and formats (text-only vs larger text combined with coloured pictograms). Warnings that targeted youth-relevant risks (i.e., road accidents or sexual assault) were considered the most meaningful and credible, although warnings communicating longer-term risks (i.e., brain, cancer) were also thought to be influential. Less-familiar risks, such as marketing manipulation and calorie intake, elicited the most negative reactions. Larger text-and-pictogram warnings were considered the most effective format in capturing attention and increasing awareness. Regardless of format and content, however, these warnings were not perceived as effective for decreasing alcohol con-sumption.
Pneumocystis jirovecii is a transmissible fungus responsible for severe pneumonia (Pneumocystis pneumonia [PCP]) in immunocompromised patients. Missense mutations due to atovaquone selective pressure have been identified on cytochrome b (CYB) gene of P. jirovecii. It was recently shown that atovaquone prophylaxis can lead to the selection of specific P. jirovecii cytochrome b mutants potentially resistant to atovaquone among organ transplant recipients. In this context, our objectives were to provide data on P. jirovecii cytochrome b mutants and putative selective pressure exerted by atovaquone on P. jirovecii organisms in France. A total of 123 patients (124 P. jirovecii specimens) from four metropolitan hospitals and two overseas hospitals were retrospectively enrolled. Fourteen patients had prior exposure to atovaquone whereas 109 patients did not, at the time of P. jirovecii detection. A 638 base-pair fragment of the CYB gene of P. jirovecii was amplified and sequenced. A total of 10 SNPs was identified. Both missense mutations C431T (Ala144Val) and C823T (Leu275Phe) located at the Qo active site of the enzyme, were significantly associated with prior atovaquone exposure, these mutations being conversely incidental in absence of prior atovaquone exposure (P < 0.001). Considering that the aforementioned hospitals may be representative of the national territory, these findings suggest that overall presence of P. jirovecii cytochrome b mutants remains low in France.
The chemical exchange between the atmosphere, crust and mantle depends on sediment recycling via subduction. However, it remains unclear how atmospherically modified sediment may affect mantle oxygen fugacity through time. The Great Oxidation Event, among the most important atmospheric changes on Earth, offers an opportunity to investigate changes in magmatism related to surface–mantle interactions. Here we use sulfur K-edge micro X-ray absorption near-edge structure spectroscopy to measure the relative abundances of S⁶⁺, S⁴⁺ and S²⁻ state in apatite inclusions hosted in 2.4–2.1-billion-year-old igneous zircons from the Mineiro Belt, Brazil. The host magmas record intracrustal melting of juvenile crust and the involvement of recycled sediments in the sub-arc mantle wedge. Unaltered apatite inclusions reveal a change from reduced to more oxidized magmas from pre- to post-Great Oxidation Event during the early Proterozoic. We argue that this change is a direct result of deep subduction of oxidized sediments and thus evidence of mantle–atmosphere interaction across the Great Oxidation Event. This suggests that the onset of sediment recycling in the Archaean provided atmospheric access to the mantle, and early ‘whiffs’ of oxygen may have already contributed to a localized increase of calc-alkaline magmatism and related ore deposits on Earth.
This study aimed to compare the commercial dosimetric software Planet ® Dose (version 3.1.1) from DOSIsoft and the open-source toolkit GATE. Dosimetry was performed for six patients receiving 200 mCi of Lutathera ® every 8 weeks for four treatment cycles. For the dose calculation with Planet ® , SPECT/CT images were acquired at 4, 24, 72 and 192 h post-injection. After the registration of all the time points to T0, the organs of interest (OOIs) were segmented. Time-activity curves were produced and the absorbed dose was calculated using the bi-and tri-exponential fitting methods. Regarding GATE simulations, the SPECT images of the 24 h time point were utilized for the radiopharmaceutical biodistribution in the OOIs and the attenuation maps were produced using the CT images. For liver and spleen, the average relative difference between GATE and Planet ® was 9.6% and 11.1% for biexponential and 12.4% and 30.5% for triexponential fitting, respectively. The right and left kidneys showed differences up to 10.7% and 10.4% for the biexponential and up to 60.6% and 11.9% for the triexponential model, respectively. The absorbed dose calculated with GATE, Planet ® (bi-exp) and Planet ® (tri-exp) was in agreement with the literature. The results of the bi-exponential fitting were similar to the GATE-resulted calculations, while the tri-exponential fitting had a higher relative difference.
Joseph-Marie Loaisel de Tréogate (1752–1812) retrouve des lettres de noblesse grâce à l’édition soignée des Nouvelles et contes procurée par Charlène Deharbe et Françoise Gevrey. Le recueil témoigne de ses premiers pas dans la carrière littéraire, dont le succès est attesté par les rééditions, traductions et critiques. Dans ces récits courts et sombres, écrits à la première personne, à l’exception de La Comtesse d’Alibre, Loaisel entend mettre en forme une ‘science du cœur humain’ (p. 390) imprégnée d’un néostoïcisme sensualiste médiatisé par la lecture de Rousseau. Le titre Nouvelles et contes signale la fluctuation générique — ‘anecdote’ ou ‘histoire’ dans les titres des œuvres, ou ‘petits contes moraux’ dans l’Avertissement des Soirées de mélancolie (p. 249) — encore vivace à la fin du siècle, en la rapportant à une dénomination des fictions brèves également familière au lecteur d’aujourd’hui. Les textes préfaciels et notes de l’auteur constituent à cet égard un état de sa pensée sur le récit sombre. Aussi les éditrices discutent-elles méthodiquement les usages terminologiques remarquables chez Loaisel (anecdote, conte, nouvelle…), de sorte qu’apparaissent ainsi clairement l’hybridité de ces récits et l’effet d’une esthétique nouvelle sur leur composition. Une introduction générale et une chronologie, accompagnées d’illustrations, précèdent les textes, à la suite de quoi le lecteur trouve un glossaire, des références bibliographiques, deux index (noms et thèmes) et la table des matières. Le bref index des thèmes et notions fait signe vers tout un discours d’époque que les narrations mettent en scène. Au reste, chaque œuvre peut être lue pour elle-même, accompagnée de son apparat critique, et rangée selon l’ordre chronologique: Valmore, anecdote française (Paris: Moutard, 1776; édition de Gevrey); Florello, histoire méridionale (Paris: Moutard, 1776; édition de Deharbe); Soirées de mélancolie (Amsterdam: Arkstée et Merkus, 1777; édition de Deharbe); et La Comtesse d’Alibre, ou le Cri du sentiment. Anecdote française (La Haye et Paris: Belin, 1779; édition de Gevrey). Le choix inhabituel des premières éditions comme textes de base vient de ce qu’elles sont les seules à avoir été approuvées par l’auteur; les rééditions révolutionnaires relèvent très certainement de préoccupations commerciales de leurs éditeurs et affadissent souvent la force des récits par les modifications qu’elles introduisent: les éditrices actuelles ne manquent d’ailleurs pas d’analyser le traitement que ces réécritures ont fait subir aux textes avoués par l’auteur. Les notes critiques soulignent entre autres les récurrences dans toute l’œuvre de Loaisel et les inflexions notables du sens de certains thèmes, leur importance pour l’histoire des idées et le développement du genre sombre, permettant d’inscrire ces ‘contes’ dans une tradition à l’essor de laquelle ils participent (Alexandrine de Tencin, Edward Young, James Hervey, Thomas Gray, François Baculard d’Arnaud, Jean-François Marmontel) et que perpétuent diversement les Crimes de l’amour ou Les Natchez. Muni de cette édition, le lecteur redécouvre avec plaisir ces récits pathétiques et sombres, succès de leur époque, tout en en appréciant la subtile et complexe singularité.
Decompression sickness (DCS) with neurological disorders includes an inappropriate inflammatory response which degenerates slowly, even after the disappearance of the bubbles. There is high inter-individual variability in terms of the occurrence of DCS that could have been mastered by the selection and then the breeding of DCS-resistant rats. We hypothesized the selection of single-nucleotide polymorphisms (SNPs) linked to autoimmunity operated upon a generation of a DCS-resistant strain of rats. We used the candidate gene approach and targeted SNPs linked to the signaling cascade that directly regulates inflammation of innate immunity transiting by the Toll-like receptors. Twenty candidate SNPs were investigated in 36 standard rats and 33 DCS-resistant rats. For the first time, we identify a diplotype (i.e., with matched haplotypes)-when coinherited-that strengthens protection against DCS, which is not strictly homozygous and suggests that a certain tolerance may be considered. We deduced an ideal haplotype of six variants from it (MyD88_50-T, _49-A, _97-C coupled to NFKB_85-T, _69-T, _45-T) linked to the resistant phenotype. Four among the six identified variants are located in pre-and/or post-transcriptional areas regulating MyD88 or NFKB1 expression. Because of missense mutations, the other two variants induce a structural change in the NFKB1 protein complex including one damage alteration according to the Missense3D algorithm. In addition to the MyD88/NFKB1 haplotype providing rats with a strong resistance to DCS, this also highlights the importance that the immune response, here linked to the genetic heritage, can have in the development of DCS and offer a new perspective for therapeutic strategies.
Fondés en 1979 à l’initiative du Comité régional olympique et sportif de La Réunion, les Jeux des îles de l’océan Indien (JIOI) s’installent dans les décennies suivantes dans la myriade des “jeux régionaux.” Réplique micro-scalaire des Jeux olympiques, ils sont impactés par le phénomène de globalisation à l’échelle mondiale – quand bien même ils se veulent avant tout vitrine sportive de l’espace indianocéanique. À ce titre, les JIOI sont gagnés par un processus d’homogénéisation au regard des standards sportifs internationaux. Toutefois, persiste une forme de polarisation eu égard à ce référentiel normatif, liée à des paramètres locaux en termes politiques, sociaux, économiques ou encore territoriaux. À travers le paradigme de l’identité culturelle et certaines opportunités relatives à la coopération régionale, les JIOI sont également marqués par un processus d’hybridation ascendant. En somme, ils sont un exemple heuristique des variations et ambivalences de la globalisation du sport au tournant des XXe et XXIe siècles. / Founded in 1979 at the initiative of the Regional Olympic and Sports Committee of Reunion Island, the Indian Ocean Island Games (IOIG) settled in the following decades within the myriad of “regional games.” A micro-scalar replica of the Olympic Games, they are impacted by the phenomenon of globalization on a world scale – even if they want to be, above all, a sports showcase of the Indian Ocean space. As such, the IOIG have been homogenized with regard to international sports standards. However, a form of polarization persists with respect to this normative reference, linked to local political, social, economic or territorial parameters. Through the paradigm of cultural identity and opportunities related to regional cooperation, the IOIG are also marked by a process of upward hybridization. In sum, they are a heuristic example of the variations and ambivalences of the globalization of sport at the turn of the twentieth and twenty-first centuries.
Copper–oxygen adducts are known for being key active species for the oxidation of C–H bonds in copper enzymes and their synthetic models. In this work, the synthesis and spectroscopic characterizations of such intermediates using dinucleating ligands based on a 1,8 naphthyridine spacer with oxazolines or mixed pyridine-oxazoline coordination moieties as binding pockets for copper ions have been explored. On the one hand, the reaction of dicopper(I) complexes with O2 at low temperature led to the formation of a µ-η2:η2 Cu2:O2 peroxido species according to UV-Vis spectroscopy monitoring. The reaction of these species with 2,4-di-tert-butyl-phenolate resulted in the formation of the C–C coupling product, but no insertion of oxygen occurred. On the other hand, the synthesis of dinuclear Cu(II) bis-µ-hydroxido complexes based on pyridine–oxazoline and oxazoline ligands were carried out to further generate CuIICuIII oxygen species. For both complexes, a reversible monoelectronic oxidation was detected via cyclic voltammetry at E1/2 = 1.27 and 1.09 V vs. Fc+/Fc, respectively. Electron paramagnetic resonance spectroscopy (EPR) and UV-Vis spectroelectrochemical methods indicated the formation of a mixed-valent CuIICuIII species. Although no reactivity towards exogeneous substrates (toluene) could be observed, the CuIICuIII complexes were shown to be able to perform hydroxylation on the methyl group of the oxazoline moieties. The present study therefore indicates that the electrochemically generated CuIICuIII species described herein are capable of intramolecular aliphatic oxidation of C–H bonds.
The southeastern tip of Cuba Island is limited to the south by the N‐Caribbean boundary. By revisiting the impressive sequences of coastal terraces of this region, we decipher the Quaternary deformation pattern of this plate boundary. We present a detailed mapping of coastal terraces uplifted over a hundred kilometers of coastline, and U/Th dating. At Punta de Maisí, the deformation pattern shows (a) a faster uplift close to the transform boundary and (b) a northward propagation of folding produced by the convergence of the Bahamas platform toward the Caribbean plate. Along the southern coast of Punta de Maisí, the sequence displays 29 coastal terraces up to 520 m in elevation and a upper Pleistocene uplift rate of 0.23 ± 0.07 mm yr⁻¹. We interpret this deformation as resulting from an offshore north‐dipping reverse fault near the coast. This uplift rate corresponds to 3% to 1.6% of the short‐term horizontal slip rate of Septentrional Oriente Fault Zone (10 ± 0.1 mm yr⁻¹). Along the northern coast of Punta de Maisí, the sequence displays height coastal terraces up to 220 m in elevation and the uplift rates amount to 0.1 ± 0.05 mm yr⁻¹ and likely result from the reverse faulting and folding associated with the offshore North Hispaniola Fault Zone. Uplift rates quickly decrease to the West, in agreement with the westward decrease in the activity of the North Hispaniola Fault Zone due to the docking of the Bahamas Platform against Cuba, while the platform more gently underthrusts Cuba to the East.
Purpose The objective of this work was to assess, in a quantitative and qualitative way, the teaching of cervical and abdominal anatomy via ultrasound for medical students. Methods For several years, tutorials on the study of anatomy through use of ultrasound on the living organism have been given at the Medical School of Brest. These sessions have focused on cervical anatomy and abdominal anatomy. Students were invited to quantitatively assess these lessons by taking two tests containing questions on both cervical and abdominal anatomy and ultrasound technique: a pre-test administered at the beginning of the year and a post-test at the end of the year. In addition, a qualitative assessment was carried out at the end of the year. Ten statements were presented, and students were asked to indicate their agreement or disagreement to a four-point Likert scale. Results One hundred and twelve students answered all the questions on the pre-test with an average of 13.4 correct answers out of 20. Forty-eight students answered all the questions on the post-test with an average of 14.6/20. Twenty-six students who benefited from the courses gave positive feedback about the workshops on the qualitative assessment at the end of the year (median scores > = 3/4). Conclusion The results of this work suggest that the use of ultrasound makes a positive contribution to the teaching of anatomy. The students interviewed think this type of tutorial should be an integral part of the anatomy curriculum at our university. In addition, this type of instruction can serve to introduce the use of ultrasound itself in a practical learning setting.
Many applications in seismology require to isolate earthquake clusters from a background activity. Relative declustering methods essentially find a 2D representation of an earthquake catalogue that distinguishes between two classes of events: crisis and non-crisis events. However, the number of statistical and/or physical parameters to be used is often limited due to the difficulty of concatenating the information onto a physically meaningful 2D grid. In this study, we propose to alleviate the declustering task by using the ability of unsupervised artificial intelligence to model complex spatio-temporal relationships directly from data. Through a data-driven approach, we define an easily transferable declustering model that provides declustering results with fewer assumptions and no prior selection of thresholds. We first obtain this model by training a self-organising neural network (SOM) that learns to cluster data points according to their feature similarity on a 2D map. We then assign each SOM cluster a label (crisis or non-crisis class) using an agglomerative clustering procedure. We quantify the classification uncertainty by developing a probabilistic function based on the projection learned by SOM. Our method is applied to a synthetic dataset and to real catalogues from the Gulf of Corinth, Central Italy and Taiwan. We discuss the validity of the method by estimating its classification accuracy. For real data, we qualitatively compare our results to previous declustering attempts. We show that our approach is easy to handle, provides a fairly new representation of earthquake catalogues and has the potential to reduce classification ambiguities between nearby events.
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3,287 members
Frederic Lancien
  • Laboratoire des Sciences de l’Environnement Marin- LEMAR (UMR 6539)
Alain Plantec
  • Département d'Informatique (Brest)
Yann Le Grand
  • Département de Physique
Brest, France