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Interlaboratory Performance Study of Cyanobacteria DNA Reference Materials Using a qPCR Format for Monitoring Cyanobacterial Blooms
No full textInternational audienceDigital PCR (dPCR) has increasingly been used as a primary measurement method for the characterization of nucleic acid reference materials. Nucleic acid reference materials are particularly useful when used for the validation and calibration of quantitative PCR (qPCR). In this study, we describe the development and characterization of Cyanobacteria DNA reference materials (RM) using dPCR. An international interlaboratory study involving 14 laboratories was conducted using the Cyanobacteria DNA RM in combination with a lyophilized PCR reagent designed for the monitoring of Cyanobacteria bloom events. Of the 55 scored study results obtained using qPCR‐based techniques, 62% were within the 8% relative expanded uncertainty based on dPCR measurements, while 100% of the study results returned satisfactory z scores calculated using a set performance coefficient of variation equivalent to one Ct value. The study participants' results indicate that the cyanobacteria DNA RM is fit for the purpose of method validation and quality control of the qPCR format used for monitoring toxic cyanobacteria algae bloom events. Most importantly, the study results demonstrated that the use of standardized reagents combined with highly characterized nucleic acid RMs allows qPCR‐based DNA quantification technology to reach levels of accuracy and reproducibility comparable to those achieved with digital PCR technology
Technical Stroke Regulations Discriminate Pacing Effectiveness During a 5-km Indoor Pool Race
No full textInternational audiencePurpose: To investigate technical regulation mechanisms of long-distance swimmers that differentiate optimal pacing strategies and the underlying kinematic parameters. Methods: Twenty-one national and international swimmers were equipped with a sacrum-worn inertial measurement unit performed during 5000-m indoor French championships. Percentage of critical swimming speed (CSS), stroke rate, stroke length, jerk cost, stroke index, and mechanical proficiency score were computed by lap. Athletes were divided into groups of pacing effectiveness based on optimal potential performance level (OPPL)—optimal (nearOPPL) and suboptimal (farOPPL)—using functional clustering of percentage of the CSS. Race sections were analyzed with a change-in-slope detection method. Common stroke-regulation abilities and deviations by pacing groups were profiled by fitting hierarchical generalized additive models between mechanical variables and laps. Results: The 2 clusters were discriminated by percentage of the CSS sustainment (P < .01). Optimal performers showed a +41.4% more stable pacing (2 race sections vs 3 for farOPPL) and a +36.7% higher end spurt, with a trend combining higher overall stroke rate (P = .08) with lower jerk cost (P = .17). Functional profiles showed that maintaining a higher stroke length and stroke index in a fatigued state, rather than overall values, allows the swinner to reach OPPL (P < .001). High regulation of mechanical proficiency score across the race, in line with pacing expectations of particular race sections, is a game changer to sustain CSS (P < .001). Conclusions: Specific profiles of stroke regulations, regarding tradeoff between stroke smoothness and resultant speed, lead to optimal pacing during the 5000-m. The results of this study enhance the technical understanding of optimal pacing in long-distance pool races for coaches and swimmers
Method for Quantifying the Criticality of Laser Cutting Defects: Influence of Morphologies on Design Parameters
No full textInternational audienceLaser cutting is an established, multi-physical process widely adopted by the metallurgical industry. However, this fast industrialisation has had a significant impact on quality control. Reviews from 2008 to 2022 primarily focus on single-criterion quality approaches, targeting defects like the Heat-Affected Zone, surface roughness, or kerf geometry, rather than adopting comprehensive methods. In addition, these studies show that cutting quality can be improved by selecting laser manufacturing parameters and part parameters such as thickness or material. However, the influence of part morphology remains underexplored. Following this observation, this study proposes a generic and complete method adapted from the Failure Modes, Effects and Criticality Analysis, allowing the evaluation of the criticality of all cutting defects in a part. It focuses on six laser cutting defects defined in an international standard and three types of morphology: arcs, angles and segments. The aim is to establish a holistic approach linking morphologies to all defect types. Industrial application reveals that thermal defects are highly influenced by morphology. Burrs and adherent slag are particularly critical in arcs and angles, while segments are less sensitive. This analysis establishes design limits and offers practical tools to improve industrial laser cutting through detailed quality assessments
Enhancing IMU Accuracy in MRAVs: A Theoretical and Experimental Approach to Vibration Damping
No full textInternational audienceThis paper analyses the problem of mechanical vibrations on Flight Controllers (FCs) of Multi-Rotor Aerial Vehicles (MRAVs) and proposes solutions based on vibration theory. First, we analyze the raw Inertial Measurement Unit (IMU) data obtained from real flights to understand the dynamical characteristics of a baseline damping configuration.We confirm that the motor-propeller units are the main source of vibration in these systems. We then develop two models used to understand how to effectively damp vibrations on IMU. We improve the baseline configuration using commonly available components placed according to a theoretical analysis and we discuss the experimental results. The new damping configuration greatly decreases the amplitude of vibrations on acceleration and angular velocity measurements.</p
New coastal records in northern Brittany (Plouescat, NW France): Sedimentological, palynological and paleogenomic data over the last 7.3 ka BP
No full textInternational audienceThe multidisciplinary approach conducted on the coastal cores ANE-C3 and PADMé (48°38'54.5114\"N; 4°10'21.3848\"W; Kerallé watershed, NW Brittany, NW France) revealed paleoenvironmental trajectories under both relative sea level rise and anthropogenic dynamics during Middle to Late Holocene, in the research paper: \"From a coastal plain to an anthropized fluvial valley (NW Brittany, France): 7.3 kyr of paleoenvironmental evolution from sedimentological, palynological and paleogenomic perspectives\" [1]. This additional article presents all the ANE-C3 and PADMé cores dataset discussed in [1] including sedimentological (XRF, grain size), palynological (pollen assemblages) and paleogenomic (plant and mammal sedimentary ancient DNA or sedaDNA) data. For the sedimentological data, the documents included here comprise high-resolution photographs and normalization of XRF-counts. A special emphasis was placed on characterising the modern pollinic signal in different sub-environments (i.e., salt marsh, coastal meadow, field) of the studied area. This was done to identify anthropogenic pollen indicators specific to this coastal zone, and, ultimately to detect more precisely the pollinic signature of human disturbances in the fossil record. Finally, this paper provides additional information on the methodologies developed, with a particular emphasis on sedaDNA analysis
Was Delphi the Centre of the World ? The Myth of the Omphalos and the Road-Network of Ancient Delphi
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Insights into electron-lattice coupling, excitonic polarons and lattice polymorphism in 3D halide perovskites
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Unifying the Absolute Configuration of Dibenzopyrrocoline Alkaloids with Relative Configuration Revision of Cryptowolinol and Description of Isocryptaustoline from Cryptocarya oubatchensis
No full textInternational audienceDibenzopyrrocoline alkaloids, found in lauraceous and hernandiaceous plants, have been studied since the 1950s. The absolute configuration of these alkaloids, including cryptaustoline, has been a topic of debate due to conflicting studies. Having in our laboratory some authentic samples of dibenzopyrrocoline-type Cryptocarya alkaloids, we decided to reinvestigate their absolute configuration using modern spectroscopic techniques along with TDDFT calculations. The NMR reinvestigation of the authentic sample of cryptowolinol led us to revise its relative configuration using ML-J-DP4 and DP4+ analyses. Moreover, the absolute configuration of all dibenzopyrrocoline alkaloids reported to date benefitted from a complete re-evaluation based on a comparison with TDDFT-SR and TDDFT-ECD predictions leading to a unified absolute configuration. At last, this patrimonial reinvestigation unveiled a historical sample corresponding to a heretofore unpublished dibenzopyrrocoline alkaloid, which we named isocryptaustoline. The reisolation of this molecule from the total alkaloid extract of Cryptocarya oubatchensis makes it a genuine natural product
Dynamics of an algae–bacteria microcosm: Photosynthesis, chemotaxis, and expulsion in inhomogeneous active matter
No full textInternational audienceIn nature, there are significant relationships known between microorganisms from two kingdoms of life, as in the supply of vitamin B 12 by bacteria to algae. Such interactions motivate general investigations into the spatiotemporal dynamics of metabolite exchanges. Here we study by experiment and theory a model system: a coculture of the bacterium Bacillus subtilis , an obligate aerobe that is chemotactic to oxygen, and a nonmotile mutant of the alga Chlamydomonas reinhardtii , which photosynthetically produces oxygen when illuminated. Strikingly, when a shaft of light illuminates a thin, initially uniform suspension of the two, the chemotactic influx of bacteria to the photosynthetically active region leads to expulsion of the algae from that area. We propose that this effect arises from advection by the inhomogeneous bacterial concentration. The resulting generalization of Fick’s law has been proposed in the context of chemotaxis and is mathematically related to the “turbulent pumping” in magnetohydrodynamics