HAL Portal ESPCI (Ecole Supérieure de Physique et de Chimie Industrielles)
Not a member yet
13939 research outputs found
Sort by
Actualités 2024 : « Year in Review » du Congrès du sommeil. Une rétrospective incontournable
No full textNational audienceThe annual news session, "Year in Review", provides a retrospective of the year's major publications, offering a unique opportunity to discover or recall the most significant publications of the year. This session brought together five experts to summarize the latest updates in five key sleep-related topics
: Laudatio: Miguel Julve et Francisco Lloret, une paire amicale de deux chimistes de coordination exceptionnels en magnétisme moléculaire
No full textInternational audienceThis laudatio is dedicated to Professors Miguel Julve Olcina and Francisco Lloret Pastor on the occasion of their retirement in 2024. The first part deals with the scientific trajectory of the Coordination Chemistry team at the University of Valencia, within the Department of Inorganic Chemistry on the Burjassot campus and then in the Paterna Institute of Molecular Science. The second part relates some of the more salient results of the heritage left by our two colleagues in molecular magnetism, where they developed, in their own way, a rational approach to designing, creating and understanding a wealth of brand new systems from the simplest to Multifunctional Molecule-based Magnetic Materials. The robust and friendly links between our two colleagues are emphasized in the third part
Design and synthesis of glycofullerene derivatives as novel photosensitizer for potential application in PDT to treat cancer
No full textInternational audienceCancer is one of the most aggressive diseases known to humanity, characterized by low survival rates and poor prognoses. Currently, platinum-based anticancer drugs and traditional photosensitizers used in photodynamic therapy (PDT) are the most widely employed treatment modalities. However, the platinum-based medications, particularly cisplatin, the most commonly used agent, have several drawbacks. These drawbacks may include systemic toxicity, which can manifest as nephrotoxicity, neurotoxicity, ototoxicity, or emesis during treatment. Such side effects can severely impair patients and significantly diminish the overall effectiveness of therapeutic interventions. In contrast, photodynamic therapy does not present these disadvantages. PDT offers numerous benefits, including reduced long-term morbidity, minimal systemic toxicity, low invasiveness, negligible drug resistance, and temporal and geographic selectivity, all of which enhance patients' quality of life. Consequently, the search for novel, effective, and practical photosensitizers is essential. Fullerenes possess unique physicochemical properties that make them highly suitable as photosensitizers. In this study, we developed a comprehensive and straightforward synthesis for two water-soluble sugar fullerene derivatives, designated as 12 and 13. Multiple analytical techniques, including 1 H NMR, 13 C NMR, high-resolution mass spectrometry (HRMS), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy, collectively confirmed the chemical structures of these derivatives and validated their successful synthesis. Upon exposure to white light irradiation at an intensity of 2.5J/cm², compound 13 demonstrated significant biological activity against three distinct tumor cell lines: HepG2, MKN45, and RPMI 4788, with IC 50 values of 5.65μM, 2.43μM, and 1.82μM, respectively. This study establishes a foundation for the development of innovative clinical photosensitizers
Modulating carbon dots from aggregation-caused quenching to aggregation-induced emission and applying them in sensing, imaging and anti-counterfeiting
No full textInternational audienceAggregation Induced Emission Carbon Dots (AIE-CDs) address the problem of conventional CDs being quenched in the solid-state. However, there are still challenges in comprehending the luminescence mechanism. This work proposed a strategy for preparing green, yellow, and near-infrared CDs by modifying the functional groups on the precursor from hydroxyl and amino to p-methylenediamine, in which electronic supply capacity determined the redshift. Additionally, The CDs' properties transformed from Aggregation-Caused Quenching (ACQ) to AIE was realized by substituting non-rotatable hydroxyl or amino groups with the rotatable p-methylenediamine on the precursor. The resulting CDs were then applied in multifield.C-CDs was used for ratiometric detection of Al 3+ and F -in pure water through three methods including fluorometer, test strip and smartphone. R-CDs was used for imaging cell nucleus and zebrafish. NIR-CDs (λ em = 676 nm) exhibits dual emission, AIE and phosphorescent characteristics was used for triple anti-counterfeiting and binary information encryption. In summary, our finding presented a strategy for preparing multicolor CDs, proposed a mechanism for the transition of CDs from ACQ to AIE, and explore their multiple applications in anti-counterfeiting, information encapsulation, sensing and imaging.</p
Impact of X‐ray Irradiation on the Chemistry and Structure of Biogenic Hydroxyapatite: The Case of Human Enamel
No full textInternational audienceThe influence of X-ray irradiation on dental tissues has been widely studied in the context of radiotherapy for the treatment of head and neck cancer. An observation common to almost all previous reports is the decrease of enamel hardness after irradiation. However, the origin of this loss of mechanical resistance remains a matter of debate. Here, we have conducted a chemical and structural study of the effect of a single 70 Gy dose on human teeth mineralized tissues. Vickers hardness of both enamel and dentin was decreased after irradiation. Microcomputed tomography showed that only the hydroxyapatite density of enamel was modified. Scanning electron microscopy, X-ray diffraction and Raman micro-spectroscopy indicated that the chemistry and crystallinity of the inorganic phase of enamel, and its organization at the micron scale, were not modified. However, Raman spectra highlighted a disorientation of hydroxyapatite nanocrystallites over the whole enamel thickness. The decrease of enamel hardness was correlated with the decrease of mineral density by assuming the presence of an additional irradiation-induced porosity. Our data suggest that X-ray irradiation can create local defects in the enamel structure, decreasing its mechanical stability. These results shed new light on the interactions between X-rays and hydroxyapatite-based materials
Structural Features and Photophysical and Antiproliferative Properties of Me<sub>2</sub>N-pbt-Cycloplatinated Complexes with Picolinate Ligands
No full textInternational audience2-(4-dimethylaminophenyl)benzothiazolate (Me2N-pbt)-cyclometalated platinum complexes containing four different picolinate ligands, [Pt(Me2N-pbt)(R-pic-κN∧O)] (R = 3-H 1, 3-NH2 2, 3-OH 3, 4-COOH 4) were prepared and examined for their photophysical properties, singlet oxygen production, and bioactivity. X-ray studies of 1 and 3·CHCl3 revealed aggregation to give 1D infinite chains. They showed phosphorescent emissions essentially associated with metal-perturbed 3ILCT excited states in 1–3 and mixed 3LL′CT/3ILCT (L = Me2N-pbt, L′ = pic) in 4, in agreement with theoretical calculations. Their tendency to self-assemble was demonstrated in films (1, 3) and DMSO/H2O (3). Complexes 1–3 showed singlet oxygen photosensitization quantum yields (ϕΔ 1O2) in the range of 13–17%. The in vitro biological activity toward selected cell lines in dark conditions and under 5 min irradiation at 450 nm was tested. Complex 3 showed the highest phototoxicity with up to 10 times improvement of the antiproliferative activity upon irradiation, with EC50 values in the nanomolar range, related to overproduction of ROS in dark conditions, further enhanced upon irradiation. Complexes 1–4 did not bind to DNA, while the most potent complex 3 demonstrated interaction with BSA and photooxidation of NADH. Finally, intracellular dose-dependent ROS production in MDA-MB-231 cells treated with 3 was observed in the dark and further stimulated upon blue light irradiation
Improving propulsive efficiency using bio-inspired intermittent locomotion
No full textInternational audienceMany swimmers, especially small- to medium-sized animals, use intermittent locomotion that differs from continuous swimming of large species. This type of locomotion, called burst and coast, is often associated with an energetic advantage. In this work, we investigate the intermittent locomotion inspired by fish locomotion but applied to a propeller. The energy consumption of burst-and-coast cycles is measured and compared to the continuous rotation regime. We show that a substantial drag ratio between the active and passive phases of the motion, as observed in fish, is critical for energy savings. Such a contrast can be obtained using a folding propeller that passively opens and closes as the propeller starts and stops rotating. For this reconfigurable propeller, intermittent propulsion is found to be energetically advantageous, saving up to 24% of the energy required to cruise at a given speed. Using an analytical model, we show that intermittent motion is more efficient than continuous motion when the drag reduction in the coast phase exceeds 65%. For fish-like locomotion, this threshold seems to be closer to 30%. A formal analogy allows us to explain the difference between propeller propulsion and fish locomotion
Influenza vaccine effectiveness against detected infection in the community, France, October 2024 to February 2025
No full textInternational audienceInfluenza circulates at high levels in Europe since November 2024. Using a test-negative study based on data from French community laboratories between October 2024 and February 2025, we estimated vaccine effectiveness (VE) against PCR-detected influenza infection (44,420/15,052; positive/negative individuals). For all age groups, the overall VE was 42% (95% CI: 37–46%), with 26% (95% CI: 18–34%) against influenza A and 75% (95% CI: 66–82%) against influenza B. Among individuals ≥ 65-year-olds VE was 22% (95% CI: 13–30%) and among 0–64-year-olds, 60% (95% CI: 56–65%)
Ethyl 4-Ene-4-ferrocenyl-5,5-bis-(4-hydroxyphenyl)-pentanoate
No full textInternational audienceThe ferrociphenol family is a group of molecules in which a ferrocenyl moiety is connected to at least one 4-hydroxyphenyl group through a C-C double bond. Among them, ferrocidiphenols in which the double bond is substituted by two gem 4-hydroxyphenyl groups have been largely studied, demonstrating interesting anticancer properties. The fourth available position of the double bond could be substituted by a simple ethyl group (1a) inherited from Tamoxifen, but also by ethyl or methyl acetate, propionate, butanoate, pentanoate (1b-g), hydroxyethyl or hydroxypropyl (1h–i). Ethyl 4-ene-4-ferrocenyl-5,5-bis-(4-hydroxyphenyl)-pentanoate 1e shows an IC50 on the MDA-MB-231 breast cancer cell line very close to that of 1a. These compounds were synthesized in moderate to good yields by McMurry coupling reaction from the corresponding ketones. Ethyl 4-ene-4-ferrocenyl-5,5-bis-(4-hydroxyphenyl)-pentanoate (1e) was fully characterized by 1H NMR (including COSY), 13C NMR (including DEPT135), low resolution mass spectrometry, HRMS, infrared spectroscopy, elemental analysis, and X-ray diffraction (XRD). The data of already published crystal structures of five structurally related ferrocidiphenols are also included for comparison purposes
Probabilité de cassure pour des bulles en turbulence
No full textInternational audienceBubbles drive gas and chemical transfers in various industrial and geophysical contexts, in which flows are typically turbulent. As gas and chemical transfers are bubble size dependent, a robust quantification requires a prediction of bubble breakup. The most common idea, introduced independently by Kolmogorov in 1949 and Hinze in 1955, is to consider a sharp limit between breaking and non breaking bubbles, given by We c ≈ 1, where the Weber number We is the ratio between inertial and capillary forces at the bubble scale. In the statistically stationary state, We c sets the maximum bubble size. Yet, due to the inherent stochasticity of the flow every bubble might in reality break. In this work, we use a stochastic linear model previously developed to infer the breakup probability of bubbles in turbulence as function of both We and the residence time. This allows us to introduce a definition of the critical Weber number accounting for the time spent by bubbles within a turbulent region, extending the stationary description. We show that bubble breakup is a memoryless process, whose breakup rate varies exponentially with We -1 . The linear model successfully reproduces experimental breakup rates from the literature. We show that the stochastic nature of bubble breakup is central when the residence time of bubbles is smaller than ten correlation times of turbulence at the bubble scale: the transition between breaking and non breaking bubbles is smooth and most bubbles can break. For large residence times, the original vision of Kolmogorov and Hinze is recovered.Les bulles contrôlent les réactions chimiques et les transferts de gaz pour un grand nombre de situations industrielles et naturelles caractérisées, typiquement, par des écoulements turbulents. Les transferts de gaz aux interfaces et les réactions chimiques étant fonction de la taille des bulles, pour les décrire précisément il est nécessaire de connaître leur distribution de taille et en particulier de prédire leur cassure. L’idée la plus répandue, introduite indépendamment par Kolmogorov en 1949, puis Hinze en 1951, consiste à considérer une limite stricte entre bulles stables et instables, donnée par We, où le nombre de Weber, We, est le ratio entre forces inertielles et capillaires à l’échelle de la bulle. En régime statistiquement stationnaire, Wec ≈ 1, fixe une taille maximum. Or, de part le caractère intrinsèquement fluctuant de la turbulence, toutes les bulles pourraient en réalité casser. Dans ce travail, nous utilisons un modèle linéaire stochastique développé précédemment pour prédire la probabilité de cassure en fonction du We, mais aussi du temps passé par les bulles dans l’écoulement turbulent, nommé le temps de résidence. Ceci nous permet d’introduire un Wec qui prend maintenant en compte le temps de résidence, étendant ainsi la vision stationnaire. Nous montrons que le processus de cassure est un processus sans mémoire, associé à des taux de cassure variant exponentiellement en We-1. Ce modèle linéaire reproduit les taux de cassure expérimentaux présents dans la littérature. Nous montrons que la nature stochastique de la cassure est centrale lorsque les temps de résidence sont inférieurs à 10 temps de corrélation de la turbulence à l’échelle de la bulle : la transition entre bulles qui cassent et qui ne cassent pas est continue et la majorité des bulles peuvent casser. En revanche, pour des temps longs, nous retrouvons la limite stricte introduite par Kolmogorov et Hinze