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Rapid characterisation of millimetre-tall vertically aligned carbon nanotube arrays: growth optimisation by tuning the catalyst film thickness
No full textInternational audienceThis study aims to establish a quick and sustainable approach for optimising the growth of millimetre-tall vertically aligned carbon nanotube (VACNT) arrays through simple catalyst tuning. To achieve this swiftly, a rapid and handy characterisation protocol is essential. Herein, we propose and validate such a method for the rapid characterisation of VACNTs, which concurrently improves upon the traditional weight-gain density calculation for VACNT arrays. We demonstrate the efficacy of this combined strategy by systematically investigating the influence of iron (Fe) catalyst film thickness (0.8–2.0 nm) on the microstructure and density of VACNT arrays synthesised via thermal chemical vapour deposition (TCVD). Catalyst morphology was characterised by atomic force microscopy (AFM), while transmission electron microscopy (TEM) provided nanotube diameter and wall-number distributions. Scanning electron microscopy (SEM) measured array height for areal density estimation, with Fourier component analysis of SEM cross-sections applied to correct height underestimations from tube tortuosity. It was observed that increasing Fe thickness enlarges and broadens catalyst particle distributions, enabling modest tuning of VACNT dimensions without compromising packing density. An optimum film thickness of ∼1.1 nm was identified, maximising areal density at ∼2 × 1010 CNTs cm−2. The integrated imaging and analysis approach presented here offers a practical and efficient pathway for rapid VACNT microstructure control and density assessment, facilitating future optimisation cycles. Furthermore, a transition in growth mode was observed, which further confirms the decisive role of the catalyst film thickness
Regioselective C-alkylation in a series of functionalized 1,2,3-triazoles: An unexpected preference over O-alkylation
No full textInternational audienceA series of novel 1,2,3-triazole derivatives were synthesized via Cu(I)-catalyzed click chemistry, introducing structural diversity at positions 1 and 4 of the triazole ring, to explore their reactivity toward alkylation. Attempts to perform O-alkylation on hydroxymethyl-substituted triazoles unexpectedly led to unreported regioselective C-alkylation at the methylene adjacent to the triazole ring. The C-alkylation was optimized using DBU and choline acetate in acetonitrile and subsequently examined across a range of alkyl and benzyl bromides to establish its scope and generality. The resulting racemic C-alkylated products were fully characterized, including confirmation of the regioselectivity by X-ray crystallography, and their enantiomers were separated by supercritical fluid chromatography. This work reveals a novel and synthetically valuable C-alkylation pathway for 1,2,3-triazoles, offering new opportunities for the development of structurally diverse and potentially bioactive triazole derivatives
Another World Is Possible—It Is Already Here: A Review and Research Agenda on Alternative Organizing
No full textInternational audienceAmid multiple crises on a planetary scale, alternative organizing offers plural possibilities for reconfiguring societal relations and bringing into being a more livable world. Despite growing interest, the literature on alternative organizing remains fragmented, marked by a narrow and selective integration of disciplinary and geographic knowledge communities. This fragmentation leads to ambiguities and contradictions in concepts and theory development. To address these issues, we review 50 years of research on alternative organizing, following three steps. First, we map the genealogy of research on alternative organizing, identify its relations with institutional orders, and distinguish key perspectives. Second, we develop an integrative framework that (a) identifies three constitutive dimensions of alternative organizing—imaginaries, alterity, and subjectivities—and (b) synthesizes the processes, frictions, and outcomes for societal transformation. Drawing on this framework, we suggest avenues to attune to the ways alternative organizing unsettles dominant orders and cultivates the present and future, other-wise
Responsible marketing: when using AI in customer-bank relationships
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Violences commises sur l'enfant et prétendu « droit de correction parentale » : la Cour de cassation a tranché (commentaire de l'arrêt Cass. crim. 14 janvier 2026, n° 24-83.360)
No full textInternational audienceLa chambre criminelle admet qu'aucun « droit de correction parentale » n'est reconnu en droit français, de sorte qu'un parent quicommet des violences à l'égard de son enfant, sous prétexte de pratiques éducatives, peut faire l'objet de poursuites pénales.Su
"I Don't Care About Social Control": Watching-Eye Effect Does Not Reduce Illegal Pedestrian Behaviour in France
No full textInternational audiencePedestrians often risk accidents by crossing at red lights. This study examines whether this behavior stems from risk awareness and tests the effectiveness of visual "nudges" using eye images. Conducted in Strasbourg with 2967 pedestrians, the study compared 'child's eyes', 'woman's eyes', flower images, and no signs. Results showed that eye images did not significantly reduce red-light crossings. Unexpectedly, the 'child's eyes' sign decreased waiting time, while the flower sign increased risky behavior. Jaywalking was influenced by gender, age, distraction, peer presence, and location. Unlike previous research, this study specifically examines pedestrian crossings, highlighting the limited impact of visual nudges and the need for further research into urban pedestrian decision-making and safety measures
(Un)Making mess at Europe's data borders: Order, control, critique
No full textInternational audienceCritical border and migration studies have shown that border practices are often messy, ambiguous, improvised and uncertain, while datafication has amplified messiness and its effects on migrants. Describing ‘mess’ at borders has been a critical intervention against the myth of order, homogeneity, predictability, clarity or efficiency. Yet, ‘mess’ can also open spaces for agency and resisting data borders. What do these ambiguities mean for the critical potential of diagnosing mess? Drawing on research we have conducted in border zones in France, Italy, Germany and Spain, we show that the critical potential of mess cannot be gauged through the binary of mess/order. We argue that we need to introduce a third term – control – to understand the critical potential of mess. To do so, we first unpack three dimensions of ‘mess’ – spatial, temporal and material – to situate it in relation to diagnoses of failure, friction, improvisation and non-knowledge in bordering practices. Second, we raise questions about the limits that the co-constitution of mess/order entails for critical research on data borders. Third, we show how control transforms the binary of mess/order into a question about ‘kinds of mess’
When cost metafrontiers are nonconvex in the outputs, then the production metafrontier is nonconvex: the price of a convexification strategy
No full textInternational audienceMetafrontier analysis is widely used to account for technological heterogeneity among producers. The approach involves combining a number of group-specific production possibilities sets to form a production possibilities metaset. Even though the union of the group sets normally results in a nonconvex metaset, most authors proceed as if this metaset is convex. Kerstens, O’Donnell and Van de Woestyne (2019) obtain new results on the union operator on sets under various assumptions and empirically illustrate that the popular convexification strategy is highly questionable. In this paper we transpose their results on the union operator from a production to a cost context: this is new. We then explore the extent to which convexity of the cost function is corroborated using a newly developed test. Furthermore, we check to which extent a convexification strategy is tenable when estimating a cost metafrontier. We use an original banking data set from China and the USA to illustrate the main issues. We establish that the cost function is not convex in the outputs for China and that the convexification strategy leads to potentially-biased estimates of the cost metafrontier and associated measures of efficiency
Switching cell wall-bound polysaccharides to secreted polysaccharides in lactobacilli
No full textInternational audienceBacterial exopolysaccharides (EPS) are carbohydrate polymers secreted into the environment. EPS produced by lactic acid bacteria have many valuable properties in the food and health sectors. In this study, we isolated spontaneous mutants of lactobacilli that overproduce EPS, using a selection method based on their slow sedimentation rate in a semi-liquid medium. In the mutants selected from several strains, we detected a missense mutation in epsD, which encodes a tyrosine kinase, or an insertion in epsC, which encodes its transmembrane modulator. Both genes were located within a gene cluster involved in Wzy-dependent polysaccharide biosynthesis. We then characterized selected Lacticaseibacillus rhamnosus mutants in detail to gain insights into the mechanisms involved in EPS overproduction. We demonstrated that the single mutation D94L in the EpsD catalytic site prevents EpsD autophosphorylation. The chemical structure of the overproduced EPS was established, and consists of heptasaccharide repeating units with pyruvate substituents. In the wild-type parental strain, a polysaccharide with an identical structure was found covalently bound to the cell wall (CW) and covering the bacterial surface. In conclusion, our results indicate that the switch from CW-bound polysaccharides to EPS released into the environment is associated with a defect in autophosphorylation of the EpsD tyrosine kinase