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A correlative analysis of gold nanoparticles internalized by A549 cells
Fluorescently labeled nanoparticles are widely used to investigate nanoparticle cell interactions by fluorescence microscopy. Owing to limited lateral and axial resolution, nanostructures (<100 nm) cannot be resolved by conventional light microÂscopy techniques. Especially after uptake into cells, a common fate of the fluorescence label and the particle core cannot be taken for granted. In this study, a correlative approach is presented to image fluorescently labeled gold nanoparticles inside whole cells by correlative light and electron microscopy (CLEM). This approach allows for detection of the fluorescently labeled particle shell as well as for the gold core in one sample. In this setup, A549 cells are exposed to 8 nm Atto 647N-labeled gold nanoparticles (3.3 Ă 109 particles mLâ1, 0.02 ÎŒg Au mLâ1) for 5 h and are subsequently imaged by confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Eight fluorescence signals located at different intracellular positions are further analyzed by TEM. Five of the eight fluorescence spots are correlated with isolated or agglomerated gold nanoparticles. Three fluorescence signals could not be related to the presence of gold, indicating a loss of the particle shell
Teacher learning and student outcomes in the context of classroom discourse. Findings from a video-based teacher professional development programme
We present an innovative teacher professional development programme (TPD) focusing on the re-definition of teachersâ discourse behaviour. We report findings on teacher learning and student outcomes, and reflect on practical implications and directions for future research on the programme. In the âDialogic Video Cycleâ (DVC) six teachers participated in a year-long intervention built on effective components of TPD and using videos of teachersâ own practices as tools for reflection and basis for group discussions. We compared the DVC with a traditional TPD programme (n= 4 teachers). Additionally, students (N= 226) were assessed regarding their motivational orientations and individual beliefs. Results show that effective TPD components could successfully be implemented in the DVC and that this new and innovative programme enhances teachersâ performance in classroom discourse and affects studentsâ interest in the subject, self-efficacy and domain-specific self-concept of ability positively. Thus, the DVC seems a promising tool to foster teacher learning with an impact on perceived student motivation and learning. Presentiamo un programma innovativo per lo sviluppo professionale degli insegnanti (TPD), centrato sulla ridefinizione della conduzione di interazioni verbali in classe. Sono riportati i risultati dellâapprendimento di insegnanti e studenti, e la riflessione sulle implicazioni pratiche per la ricerca futura sul programma. Nel âDialogic Video Cycleâ (DVC) sei insegnanti hanno partecipato per un anno a un intervento di TPD mediante videoregistrazioni usate come strumenti di riflessione sulle proprie pratiche e per le discussioni di gruppo. Abbiamo confrontato il DVC con un programma TPD tradizionale (n= 4 insegnanti). Inoltre sono stati valutati gli orientamenti degli studenti (N= 226) in termini di motivazione e fiducia nelle proprie capacitĂ . I risultati mostrano che le componenti efficaci del TPD potrebbero essere attuate con successo nel DVC e che questo programma migliora le prestazioni degli insegnanti nella conduzione del discorso in aula e stimola negli studenti lâinteresse per lâargomento, il senso di auto-efficacia e il concetto di sĂ©. Il DVC sembra uno strumento promettente per favorire lâapprendimento degli insegnanti con un impatto sulla motivazione e sullâapprendimento degli studenti
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