Portail HAL UNIV-RENNES
Not a member yet
180610 research outputs found
Sort by
Optimization of caper bud drying using the DT_LSBOOST model: A predictive approach to improve quality and efficiency
No full textInternational audienceCapparis spinosa L. buds undergo salting and drying to enhance their shelf life and organoleptic properties. This study evaluates the impact of four drying methods: oven drying (OD), vacuum drying (VD), freeze-drying (FD), and microwave drying (MD) on the physicochemical, antioxidant, and microbiological properties of dried caper buds. Salting reduced the initial moisture content from 508.50 % to 168.59 % (db), while drying further decreased it to approximately 9 %. Drying time varied significantly, with MD achieving the shortest duration (0.19-0.75h) and OD requiring the longest (reaching 49.66h). FD exhibited the highest energy consumption (60.77 kWh/kg), followed by VD, while OD and MD were the least energy-intensive (0.54-3.10 kWh/kg and 1.34-2.18 kWh/kg, respectively). FD preserved the most chlorophyll (193.63 mu g/g DW) and total phenolic content (28.98 mgGAE/g DW), whereas MD at 200 W resulted in the lowest TPC (9.88 mgGAE/g DW). FD samples also showed superior antioxidant activities in both ABTS and FRAP assays. In contrast, OD and MD increased browning and degraded quality attributes. Multivariate analyses (PCA and clustering) highlighted FD as optimal for preserving quality, while MD was the most detrimental. Microbiological analysis confirmed that dried capers met food safety standards. A predictive model using Decision Tree coupled with Least Squares Boosting (DT_LSBOOST) achieved exceptional accuracy (R = 0.9999, RMSE = 0.0564, ESP = 0.2028, MAE = 0.0305), providing a reliable tool for optimizing drying parameters. Overall, freeze-drying emerged as the best method to retain nutritional and bioactive properties of capers, and the developed predictive model offers an innovative approach to enhancing caper processing efficiency
Process evaluation of a school-based vaccination intervention to improve HPV vaccine coverage: A mixed-method study embedded in the French PrevHPV cluster randomized controlled trial
No full textInternational audienceBackgroundHuman papillomavirus vaccine coverage (HPV VC) remains suboptimal in many countries. French authorities launched the PrevHPV research program, which included a cluster randomized controlled trial (cRCT) to evaluate the effectiveness of an ‘at-school vaccination’ intervention. Within this trial, we conducted a process evaluation of this intervention, specifically analyzing (i) its implementation, (ii) its mechanisms of impact, and (iii) the contextual factors influencing implementation (facilitators/barriers).MethodWe conducted a mixed-method study embedded in the PrevHPV cRCT (April 2021–April 2022). ‘At-school vaccination’ consisted of vaccination day(s) on school premises where mobile vaccination teams (MVTs) initiated HPV vaccination free of charge for eligible adolescents (i.e., non-vaccinated adolescents aged 11+). Quantitative data were collected through activity reports and self-administered questionnaires of adolescents and school staff. Qualitative data collected through six focus groups with school staff and MVTs were analyzed using thematic analysis.ResultsOf the 31 schools (14,772 adolescents) randomized to implement ‘at-school vaccination’, 12 (39 %) dropped out. Among the participating schools, analysis of implementation showed that 17 % of adolescents returned valid consent forms, of whom 89 % initiated vaccination. MVTs played a central role in implementing vaccination day(s), supported by several school staff (e.g., school nurses, education assistants). Regarding mechanisms of impacts, satisfaction with the vaccination days was high among adolescents and school staff. The intervention generated both positive and negative group effects among adolescents. Contextual factors that facilitated implementation included the preparation of a list of adolescents to be vaccinated and the availability and motivation of school staff. The main barriers related to the management of consent forms and missing health records.ConclusionWe formulated recommendations for implementing at-school vaccination, which may be particularly helpful for the French school HPV vaccination campaigns that were scaled up nationally in 2023. We also discussed potential macro-level improvement strategies, involving modifications to the legislative framework
DroidHunter : une détection robuste basée sur la vision contre les logiciels malveillants Android obfusqués
No full textInternational audienceDue to their large popularity, Android smartphones are often targeted by malware attacks. Several strategies exist to detect malwarecode. However, we show that they are insufficient when dealingwith obfuscation techniques. DroidHunter is our novel methodfor detecting Android malwares. DroidHunter leverages opcodesand their parameters, transforming those into RGB images andspecific encoding techniques. The generated images are then usedto train two different classification models based on support vector machines, convolutional neural networks, and a vision-basedtransformer. We evaluate DroidHunter on several datasets withup to 476,937 APKs from multiple sources. With detection ratesfrom 98.65% to 99.94%, DroidHunter overcomes nine state-of-the-art malware detection techniques, including Drebin, MaMadroid,DexRay. Moreover, DroidHunter demonstrates strong resilienceagainst hidden malware with detection rates up to 98.98%, andshows robustness on newly emerging threats, achieving an AUT of0.89 on recent malware samples. We release our code to the researchcommunity, with instructions to reproduce our evaluation availableat: https://zenodo.org/doi/10.5281/zenodo.10977166.En raison de leur grande popularité, les smartphones Android sont souvent la cible d'attaques de logiciels malveillants. Il existe plusieurs stratégies pour détecter les codes malveillants. Cependant, nous montrons qu'elles sont insuffisantes lorsqu'il s'agit de techniques d'obfuscation. DroidHunter est notre nouvelle méthode de détection des logiciels malveillants Android. DroidHunter exploite les codes opérationnels et leurs paramètres, en les transformant en images RVB et en techniques d'encodage spécifiques. Les images générées sont ensuite utilisées pour entraîner deux modèles de classification différents basés sur des machines à vecteurs de support, des réseaux neuronaux convolutifs et un transformateur basé sur la vision. Nous évaluons DroidHunter sur plusieurs ensembles de données comprenant jusqu'à 476 937 APK provenant de multiples sources. Avec des taux de détection compris entre 98,65 % et 99,94 %, DroidHunter surpasse neuf techniques de détection de logiciels malveillants de pointe, notamment Drebin, MaMadroid etACM Asia Conference on Computer and Communications Security (ASIA CCS '26)DexRay. De plus, DroidHunter fait preuve d'une forte résilienceface aux logiciels malveillants cachés, avec des taux de détection pouvant atteindre 98,98 %, et se montre robuste face aux nouvelles menaces émergentes, avec un AUT de 0,89 sur des échantillons de logiciels malveillants récents. Nous publions notre code à la communauté des chercheurs, avec des instructions pour reproduire notre évaluation disponibles à l'adresse suivante : https://zenodo.org/doi/10.5281/zenodo.10977166
Unraveling the antioxidant effect of new quinoline epoxides: Synthesis, crystal structure from PXRD, HS analysis and molecular docking's binding modes
No full textInternational audienceQuinoline derivatives are significant in organic and medicinal chemistry due to their versatile applications, especially in pharmacology. In this work, we report the synthetic pathways and structural characterization of four new quinoline epoxides derived from 2-chloro-3-formylquinoline, namely 2-chloro-3-(oxiran-2-yl)quinoline (4a), 2-chloro-6-methoxy-3-(oxiran-2-yl)quinoline (4b), 2-chloro-5,8-dimethyl-3(oxiran-2-yl)quinoline (4c) and 2-chloro-6,8-dimethyl-3(oxiran-2-yl)quinoline (4d), by using a stepwise approach involving the preparation of acetanilides, their transformation into quinoline derivatives and subsequent epoxidation. These compounds were characterized by spectroscopic FT-IR, 1HNMR , 13CNMR , 1H/1HCOSY, HSQC, high-resolution mass spectrometry (HRMS) and powder X-ray diffraction (PXRD) techniques. We have provided herein insights into the structural features of the studied compounds by analyzing their Hirshfeld surfaces and most prominent intermolecular interactions. Furthermore, we have investigated their in vitro biological implications as antioxidant agents and highlighted their in silico binding modes by carrying out molecular docking calculations against human peroxiredoxin (3MNG)
Archives et autres traces. Du rapport de l’historien(ne) à ses sources
No full textInternational audienc
LivingBench: an IoT/Edge Platform Benchmark Based on an Environmental Observation Use-Case
No full textInternational audienceIn recent years, a number of edge computing platforms have been proposed to process data produced by IoT sensors. Performing computation close to the sources of data allows faster insight and greater reliability at a lower cost compared to traditional cloud-based deployments. However, designers of IoT/edge platforms face difficult issues. In particular, exercising and testing a new platform in conditions that approach a real deployment requires a sufficient number of standard benchmarking systems capable of generating realistic workloads. In this paper, we propose LivingBench, a benchmarking tool with the capability of incorporating real or synthetic workload injection, developed to exercise edge computing systems. LivingBench integrates a real-world data trace captured in an environmental observatory, together with a collection of actual applications designed for processing these data, and a load injector tool capable of replaying a (possibly pre-processed) trace to benchmark an MQTT-based edge system. We describe the architecture of LivingBench and show how it may be used to evaluate the maximum data processing capacity of an edge system under test
Staphylococcus aureus is not a stand-alone indication for cardiac surgery in patients with infective endocarditis
No full textInternational audienc
Revisiting the time to positivity in blood cultures as a prediagnostic tool: an in vitro experiment and retrospective study
No full textInternational audienceBackground: Sepsis is an acute response to infection; rapid detection of pathogens is essential. In this work, the time to positivity (TTP) of blood culture (BC), a key factor for species diagnosis, was studied. Methods: In the experimental phase, six bacterial reference strains were tested under varying conditions, and three years of clinical blood culture data were reviewed. A total of 4,924 first positive BC bottles from 3864 patients hospitalized from 2019 to 2021 were analysed. Results: Experimental results revealed that reducing the inoculum by a factor of 10 increased the TTP by an average of 1.5 hours. A blood sample volume between 1 and 3 mL per vial significantly improved bacterial detection. Each hour of delay before incubation reduced the TTP by 21 minutes; however, the overall TTP was still prolonged. Bacterial growth and viability were preserved at room temperature for up to 24 h. TTP could be exploited as a first diagnostic tool, as it significantly varied between species. Staphylococcus aureus can be differentiated from coagulase-negative staphylococci when the TTP is <12 hours (Specificity (Sp) = 0.95, positive predictive value (PPV) = 62 %, negative predictive value (NPV) = 76 %), and Enterobacteriaceae can be differentiated from Pseudomonas aeruginosa under the same threshold (Sensibility (Se) = 0.70, Sp = 0.93, PPV = 99 %). A TTP >15 hours exclude clinically relevant pathogens such as S. pneumoniae, S. agalactiae, and S. pyogenes. Conclusion: This work shows how preanalytical factors play a major role in the time required for diagnosis, and highlights the potential of the TTP as a prediagnostic tool to improve sepsis management
Potential of Chinese Cabbage and Oat as Companion Plants to Protect Sugar Beets Against the Green Peach Aphid, Myzus persicae
No full textInternational audienceIn an attempt to develop alternative protection methods for sugar beet (Beta vulgaris) crops against yellows viruses and their main vector, the green peach aphid Myzus persicae Sulzer (Aphididae, Macrosiphini), we evaluate the potential of companion plants to attract or repel this aphid species. Host selection experiments in the laboratory revealed a strong preference of M. persicae for Chinese cabbage (Brassica rapa, subsp. pekinensis) over sugar beet plants, whereas sugar beet plants were strongly preferred over oat (Avena strigosa). These effects were confirmed in field experiments where sugar beets associated with oat were significantly less infested by aphids than control sugar beets, and Chinese cabbage hosted higher numbers of aphids and reduced numbers of wingless aphids at short distance. However, infection of sugar beets by yellows viruses was only reduced early in the season in plots with oat. In the other types of plots, infection was not reduced, and viruses were present in a large proportion of the sugar beet plants independently of the companion plant associated with beet. Our study shows that in spite of Brassicaceae and oat being promising candidates for a push–pull strategy controlling green aphid populations in the field, limited reduction of virus infection on sugar beets calls for further studies on the origin of yellows virus epidemics