Sol–gel encapsulation for power electronics utilizing 3-Glycidyloxypropyltriethoxysilane and 3-Mercaptopropyltrimethoxysilane

3-Glycidyloxypropyltriethoxysilane and 3-Mercaptosilane were used to prepare a composite together with aluminum oxide. The compound is a potential candidate for being used as inorganic encapsulation. FTIR results paired with head-space analysis revealed a hardening of the composite at above 130 °C and degradation of the sol–gel-network above 150 °C. The adhesion of these compounds was tested via shear tests. It showed, that the addition of 3-Mercaptopropyltriethoxysilane enhanced the adhesion on silver significantly. This is attributed to the covalent nature of the Ag-S bond, which is forming as compared to the solely dispersive forces, when 3-Mercaptopropyltriethxysilane is not used. By conducting the shear test under temperature activation energies for the breakages were calculated. These coincide well with the binding energy of Ag-S in case silver surfaces are examined. In the case of a copper surface, a mixture of covalent and dipole–dipole interactions are found, since the activation energy for breakage is smaller as the Cu-O bond energy

Prevention of Diabetes in NOD Mice by Repeated Exposures to a Contact Allergen Inducing a Sub-Clinical Dermatitis

BACKGROUND: Type 1 diabetes is an autoimmune disease, while allergic contact dermatitis although immune mediated, is considered an exposure driven disease that develops due to epicutaneous contact with reactive low-molecular chemicals. The objective of the present study was to experimentally study the effect of contact allergens on the development of diabetes in NOD mice. As the link between contact allergy and diabetes is yet unexplained we also examined the effect of provocation with allergens on Natural Killer T (NKT) cells, since involvement of NKT cells could suggest an innate connection between the two diseases. METHOD: NOD mice 4 weeks of age were exposed, on the ears, to two allergens, p-phenylenediamine and 2,4-dinitrochlorobenzene respectively, to investigate the diabetes development. The mice were followed for a maximum of 32 weeks, and they were either repeatedly exposed to the allergens or only sensitized a week after arrival. The stimulation of NKT cells by the two allergens were additionally studied in C57BL/6 mice. The mice were sensitized and two weeks later provocated with the allergens. The mice were subsequently euthanized at different time points after the provocation. RESULTS: It was found that repeated application of p-phenylenediamine reduced the incidence of diabetes compared to application with water (47% vs. 93%, P = 0.004). Moreover it was shown that in C57BL/6 mice both allergens resulted in a slight increment in the quantity of NKT cells in the liver. Application of the allergens at the same time resulted in an increased number of NKT cells in the draining auricular lymph node, and the increase appeared to be somewhat allergen specific as the accumulation was stronger for p-phenylenediamine. CONCLUSION: The study showed that repeated topical application on the ears with a contact allergen could prevent the development of diabetes in NOD mice. The contact allergens gave a non-visible, sub-clinical dermatitis on the application site. The preventive effect on diabetes may be due to stimulation of peripheral NKT cells, as shown for provocation with p-phenylenediamine in the C57BL/6 mouse. This epicutaneous procedure may lead to new strategies in prevention of type 1 diabetes in humans

Low zone tolerance requires ICAM-1 expression to limit contact hypersensitivity elicitation.

Painting subsensitizing doses of contact sensitizers on skin (low-dose tolerization) induces antigen (Ag)-specific tolerance, known as low zone tolerance (LZT), which has been experimentally demonstrated by the inhibition of contact hypersensitivity (CHS). Although LZT resulted from the inhibition of the sensitization phase, the effects on the effector/elicitation phase remain unknown. L-selectin and ICAM-1 regulate leukocyte influx into inflamed tissues during the elicitation phase of CHS. LZT was investigated in mice lacking either L-selectin or ICAM-1 to evaluate the roles these leukocyte receptors play in LZT during the elicitation phase. Low-dose tolerization effectively suppressed CHS in wild-type and L-selectin-deficient mice, but not in ICAM-1-deficient mice. Low-dose-tolerized ICAM-1-deficient splenocytes effectively suppressed the elicitation phase in naive wild-type recipients. Sensitized ICAM-1-deficient splenocytes showed normal proliferative responses to the sensitizing Ag and generated normal CHS in wild-type recipients. Thus, ICAM-1 deficiency did not affect sensitization. LZT was associated with a lack of ICAM-1 upregulation after elicitation, suggesting a potentially mechanistic role for ICAM-1. The blockade of IL-10, a possible mediator of LZT, produced by hapten-specific suppressor cells, abrogated LZT and restored ICAM-1 upregulation. These results indicate that low-dose tolerization controls CHS by abrogating ICAM-1 upregulation during the elicitation phase

L'erreur et l'évaluation formatrice au service des apprentissages pour le cycle 3

At school, the mistake is a part of the learning process. Through the setting up of different evaluations, the mistake becomes a tool at the learning’s disposal. On the one hand, the evaluation enables the teacher to be guided, and on the other hand it situates the pupils within the learning process. More particularly, formative assessment, located in the middle of a sequence, is a stage. The pupils correct themselves with the help of tools made available to them. This procedure enable the pupils to become aware of their own mistakes. We‘ve tried to understand how formative assessment could help the pupils make progress. Moreover, we‘ve wondered, in which extent, this approach could impact on the view that pupils had from the word “mistake”. As a prerequisite, we imagined that formative assessment combined with a file which would gather their progress, could make pupils get better. They would have a better vision of their mistakes. The figures of the study have revealed that the majority of the class pupils have reduced their number of mistakes in the given exercises. The participants have expressed a positive feeling when confronted to a mistake atthe beginning of the procedure. A questionnaire handed out one month later reinforced this feeling.L' erreur fait partie du processus d'apprentissage à l'école. A travers la mise en place de différentes évaluations, l'erreur devient un outil au service des apprentissages. Elle permet d'une part de guider l'enseignant et d'autre part aux élèves de se situer dans lors des processus d'apprentissage. Plus particulièrement, l'évaluation formatrice, située en milieu des apprentissages, est une étape qui permet aux élèves de s'auto-corriger à l'aide d'outils mis à disposition. Cette procédure va permettre aux élèves de se rendre compte de leurs erreurs. Nous avons cherché à savoir comment l'évaluation formatrice allait permettre aux élèves de progresser. De plus, nous nous sommes demandés dans quelle mesure la démarche allait avoir un impact sur la vision que se faisaient les élèves de l'erreur. Nous avons pris comme préalable que l'évaluation formatrice et la mise en place d'une pochette de progrès allait faire progresser les élèves, ils auront alors, une vision plus positive de leurs erreurs. Les données de l'étude nous ont montré qu'une majorité des élèves de classe a diminué son nombre d'erreurs dans les exercices. Les participants ont exprimer un ressenti positif face à l'erreur dès le début de la procédure. Un questionnaire un mois après le dispositif a permis de confirmer ce sentiment

Françoise Llinas Guyenot

Llinas Guyenot Françoise. Françoise Llinas Guyenot. In: Diplômées, n°278-279, 2021. 100 ans de parcours. p. 211

Adjustment of micro-optical components by a carefully measured tapping. An intelligent driving method

An effective and universally useful means of adjustment in the realm of precision engineering and microoptics becomes possible with the realization of a new drive. In contrast to traditional adjustment methods, the mechanical component will be situated in its final position before the adjustment process starts. Specific mechanical impulses (momenta) generated by a striking mechanism are transmitted to the mechanical component or its housing (carrier). This results in minute linear or fine angular motions. Prototypes of the electromechanical striking mechanism have been researched and developed. The arrangements make possible the adjustment of mirror, of fibre to fibre or of fibre to opto-electronic sensors. The measuring system with PC-based algorithm allows fast and exact positioning of these components