Caries-preventing effect of a hydroxyapatite-toothpaste in adults: a 18-month double-blinded randomized clinical trial

BackgroundDental caries is a worldwide challenge for public health. The aim of this 18-month double-blinded, randomized, clinical trial was to compare the caries-preventing effect of a fluoride-free, hydroxyapatite toothpaste (test) and a toothpaste with sodium fluoride (1450 ppm fluoride; positive control) in adults.MethodsThe primary endpoint was the percentage of subjects showing no increase in overall Decayed Missing Filled Surfaces (DMFS) index. The study was designed as non-inferiority trial. Non-inferiority was claimed if the upper limit of the exact one-sided 95% confidence interval for the difference of the primary endpoint DMFS between test and control toothpaste was less than the predefined margin of non-inferiority (Δ ≤ 20%).ResultsIn total, 189 adults were included in the intention-to-treat (ITT) analysis; 171 subjects finished the study per protocol (PP). According to the PP analysis, no increase in DMFS index was observed in 89.3% of subjects of the hydroxyapatite group and 87.4% of the subjects of the fluoride group. The hydroxyapatite toothpaste was not statistically inferior to a fluoride toothpaste with regard to the primary endpoint.ConclusionHydroxyapatite was proven to be a safe and efficient anticaries agent in oral care.Clinical trial registrationNCT04756557

Passing the frontiers of liquid-phase glycerol partial oxidation over supported bimetallic catalysts

International audienceIn this paper, the performance of monometallic and bimetallic (Au, Pt, Ag, Pd) catalysts supported on a basic alumina in the partial oxidation of glycerol in the liquid phase are compared. A clear synergetic effect between metals is observed, especially when Au and Pt, Au and Pd, as well as Ag and Pt are associated. These three catalysts, characterized by relatively small mean particle size (i.e., 4.44 ± 2.18 nm for AuPt, 6.42 ± 3.31 nm for AuPd, and 6.91 ± 3.97 nm for AgPt), enable complete glycerol (GLY) conversion after 4 h of reaction at room temperature, under atmospheric pressure (200 mL of a 0.3 m GLY solution, 0.5 g of catalyst, NaOH/GLY = 4 mol mol−1, 1500 rpm, 650 mL O2 min−1). Moreover, it is possible to achieve more than 80% GLY conversion after 4 h of reaction at room temperature under atmospheric pressure with air bubbling (650 mL air min−1) as an oxidation atmosphere. This unpreceded high performance in the glycerol partial oxidation reaction under such mild conditions pave the way to the possibility of industrial exploitation of this promising catalytic system

Modélisation cinétique de l’oxydation du glycérol en phase liquide catalysée par l’Or

National @ CDFA+DLJ:PFOInternational audienceIntroductionLe glycérol (GLY) est un polyol qui est coproduit lors de la production du biodiesel. Ce composé est considéré comme une molécule plateforme car elle peut être valorisée en différents produits d'intérêts. L’oxydation catalytique du glycérol a gagné récemment en intérêt pour la production d'acides comme l'acide glycolique. Malgré ces travaux, le mécanisme d'oxydation sur catalyseur supporté à base d'or en milieu basique n'est pas encore clarifié. C'est pourquoi nous proposons dans ce travail une étude cinétique de l’oxydation du glycérol sur Au/TiO2 dans le but d'obtenir un modèle cinétique avec une approche de type Langmuir-Hinshelwood-Hougen-Watson.RésultatsL'étude expérimentale sur la cinétique a été menée en réacteur fermé en faisant varier température, pression, concentration de NaOH et avec mélange des réactifs en compétition. A partir de l'analyse des données cinétiques, nous avons abouti au mécanisme proposé dans la Figure 1 dans lequel il est clairement démontré que l’acide formique (C1), glycolique (C2) et le glycérique (C3) sont des produits primaires [1]. Ce résultat indique que sur l'or, nous avons simultanément une oxydation sélective et une ou deux coupures C-C oxydantes. Une modélisation cinétique a été réalisée avec le logiciel MATLAB :r_i=(k_i K_i C_i)/〖(1+∑〖K_n C_n)〗〗^2 La Figure 2 présent les résultats de la modélisation après ajustements paramétriques. Il peut être observé que ceux-ci sont statistiquement significatifs. Le catalyseur étudié réduit l’énergie d’activation de toutes les réactions en comparaison avec les valeurs obtenues sans catalyseur (non montrés). De plus, les énergies d’activation des réactions r1 et r3 sont plus faibles que celles publiées par Demirel et col. (50 kJ/mol) [2]. D’autre part, les acides C3 (glycérique et tartronique) présentent les constantes d’adsorption les plus hautes. La poursuite des travaux sera focalisée sur la modélisation de l'effet de la soude et d'activation de l'O2. RemerciementsCe travail a été réalisé en partenariat avec la SAS PIVERT, dans le cadre de l’Institut Français pour la Transition Energétique (ITE) P.I.V.E.R.T. (www.institut-pivert.com) sélectionné comme un « Investissement d’Avenir ». Ce travail a été financé par « Investissement d’Avenir » supporté par le Gouvernement Français avec comme référence ANR-001Références[1] E. Skrzynska, J. Ftouni, J.S. Girardon, M. Capron, L. Jalowiecki-Duhamel, J.F. Paul, F. Dumeignil. ChemSusChem 5 (2012), 2065-2078[2] S. Demirel, M. Lucas, J. Wärna, T. Sarmi, D. Murzin, P. Claus. Top. Catal 44 (2007), 299-30

KINETIC ANALYSIS AND MODELLING FOR THE NON- AND AU-CATALYSED OXIDATION OF GLYCEROL

International @ CDFA+DLJ:PFOInternational audienceThe depletion of fossil fuels has heightened research efforts to find environmentally-friendly alternatives to petroleum-based chemicals, thereby, the production of biodiesel has increased significantly [1]. The manufacture of biodiesel lead to different co-products, among them is glycerol (GLY), which represent 10 wt.% of the final product. For this reason, the transformation of GLY in valuable chemicals (glyceric acid, glycolic acid, formic acid,etc) has gained a great interest [2]. Among the different transformation techniques, the catalytic oxidation, as a non-expensive and environmentally-friendly process, is the most developed.There are many studies which deal the kinetic analysis and modelling of the GLY oxidation. However, it is still necessary to further investigate this reaction to explain some aspects which are not clarified so far. This way, the aim of this work is to perform a kinetic modelling of the GLY oxidation. A kinetic model will be proposed by using the experimental results reported in a previous work of our groups [3] carried out in kinetic regime and a carbonbalance close to 100 %.FIG1 shows the reaction pathways selected for the preliminary kinetic analysis, by analysis of experimental results reported previously [3] where C-1 (formic), C-2 (glycolic) and C-3 (glyceric) acids have been found as primary products. Direct C-C cleavage into small acids was already reported in previous studies [4]. The first kinetic model has been proposed on formal approach, by considering first-reaction order of all components. For the parameter estimation, non-linear regression was performed by using Matlab. Finally, a statistical analysis of the estimated parameters was performed by the calculation of the standard deviations and the correlation matrix.Obtained rate constants at different reaction temperatures are listed in FIG2, along with a comparison of the calculated and experimental concentrations for the Au-catalysed reaction at 100 °C. Results revealed that the Au catalyst was active and selective towards formic and tartronic acids, and the activation energies obtained were similar than those reported elsewhere [5]. In general, the concentrations predicted with the kinetic model fittedadequately with the experimental ones. However, statistical analysis results (not shown) revealed a strong correlation between different rate constants. Therefore, the model will be improved by the incorporation of further parameters that could influence the activity of the process, such as the base concentration, the reaction orders and in the case of the Au-catalysed reactions, the adsorption constants of the GLY and the obtained products.Moreover, the reaction mechanism will be further analysed by additional experiments of competitive reactions

Kinetic modeling of the quasi-homogeneous oxidation of glycerol over unsupported gold particles in the liquid phase

SSCI-VIDE+CDFA+DLJ:JFT:PFOInternational audienc

Development of Silver Based Catalysts Promoted by Noble Metal M (M = Au, Pd or Pt) for Glycerol Oxidation in Liquid Phase

International audienc

Stress/Immune Biomarkers in Saliva among Children with ADHD Status

Background. This cross-sectional study aimed to evaluate stress and immune biomarkers in saliva samples of attention-deficit/hyperactivity disorder ADHD compared to healthy non-ADHD children. Material and methods. A total of 132 children under 11 years old (8.5 ± 1.1) enrolled in a cross-sectional study: with confirmed ADHD (n = 60) and healthy controls (n = 72). The clinical evaluation included physical measurements (height, waist, hip circumference, body weight, body mass index BMI, BMI z-score) and unstimulated saliva collection and measurements of free cortisol, salivary alpha-amylase (sAA), and secreted immunoglobulins (sIgA, IgG, and IgM) with quantitative assay (ELISA) analysis. Unpaired t-test, Welch test, or Mann–Whitney U test were applied for group comparisons when appropriate, and the correlation between variables was analyzed with Spearman’s rank coefficient. Results were considered significant at p < 0.05. Results. In the ADHD group, body weight (p ≤ 0.01), BMI (p ≤ 0.009), and hip circumference (p ≤ 0.001) significantly differed, while waist size and BMI z-score did not (p > 0.05). Significant elevation of the salivary sAA (p = 0.03), sIgA (p = 0.02), and IgM (p ≤ 0.001) biomarkers were detected, without differences in the morning cortisol (p > 0.05). Significant correlations between cortisol and BMI, hip size, and IgA, as well as between IgG and sAA and IgA were obtained. Conclusions. Saliva can be used to monitor ADHD status with regard to biomarkers indicating the hypothalamus–pituitary–adrenal axis, as HPA axis, and sympathetic activity. The results indicate that morning collection of saliva in contrast to unchanged salivary cortisol, may evaluate mentioned above system dysregulations by measurements of sAA and immunoglobulins among ADHD children

Image_1_Caries-preventing effect of a hydroxyapatite-toothpaste in adults: a 18-month double-blinded randomized clinical trial.JPEG

BackgroundDental caries is a worldwide challenge for public health. The aim of this 18-month double-blinded, randomized, clinical trial was to compare the caries-preventing effect of a fluoride-free, hydroxyapatite toothpaste (test) and a toothpaste with sodium fluoride (1450 ppm fluoride; positive control) in adults.MethodsThe primary endpoint was the percentage of subjects showing no increase in overall Decayed Missing Filled Surfaces (DMFS) index. The study was designed as non-inferiority trial. Non-inferiority was claimed if the upper limit of the exact one-sided 95% confidence interval for the difference of the primary endpoint DMFS between test and control toothpaste was less than the predefined margin of non-inferiority (Δ ≤ 20%).ResultsIn total, 189 adults were included in the intention-to-treat (ITT) analysis; 171 subjects finished the study per protocol (PP). According to the PP analysis, no increase in DMFS index was observed in 89.3% of subjects of the hydroxyapatite group and 87.4% of the subjects of the fluoride group. The hydroxyapatite toothpaste was not statistically inferior to a fluoride toothpaste with regard to the primary endpoint.ConclusionHydroxyapatite was proven to be a safe and efficient anticaries agent in oral care.Clinical trial registrationNCT04756557.</p