Low Frequency Vibrations Disrupt Left-Right Patterning in the Xenopus Embryo

The development of consistent left-right (LR) asymmetry across phyla is a fascinating question in biology. While many pharmacological and molecular approaches have been used to explore molecular mechanisms, it has proven difficult to exert precise temporal control over functional perturbations. Here, we took advantage of acoustical vibration to disrupt LR patterning in Xenopus embryos during tightly-circumscribed periods of development. Exposure to several low frequencies induced specific randomization of three internal organs (heterotaxia). Investigating one frequency (7 Hz), we found two discrete periods of sensitivity to vibration; during the first period, vibration affected the same LR pathway as nocodazole, while during the second period, vibration affected the integrity of the epithelial barrier; both are required for normal LR patterning. Our results indicate that low frequency vibrations disrupt two steps in the early LR pathway: the orientation of the LR axis with the other two axes, and the amplification/restriction of downstream LR signals to asymmetric organs

Corso di formazione e perfezionamento in campi elettromagnetici: rischi e protezione

Il testo è costituito dalla raccolta delle dispense delle lezioni e seminari presentati dai docenti nell'ottava edizione del Corso di formazione e perfezionamento in "Campi elettromagnetici: rischi e protezione". Il dibattito sull'argomento è molto attuale e vivace e il corso è diretto a rispondere alle esigenze culturali, nonché di aggiornamento e qualificazione del settore

Segmentation of nailfold capillaries from microscopy video sequences

Nailfold capillary microscopy examination has been used for long time as a non invasive technique for the diagnosis of connective tissue diseases. Computer systems helping the physician during the examination have been developed, but they still require a certain level of manual intervention. A first problem that need yet to be solved is the segmentation of the capillaries in the video sequence. In this paper we propose a software pipeline for the segmentation of the capillaries from video sequences of the nailfold. The core of the segmentation proposed is the combination into a single segmentation map of the output of a battery of simple segmentation algorithms, based only on the grey levels. The system has been tested on a set of data, for which a ground truth segmentation was obtained manually, reporting satisfactory results. We advocate that the inclusion in the battery of classifiers of ad-hoc segmentation algorithms present in the literature will produce a reliable system, that can be used by physicians

Rilievi sulle nuove norme di radioprotezione derivanti dal D.Lgs. 230/95

corso di perfezionamento in radioprotezione, Università degli Studi di Napoli Federico II Facoltà di Medicina e Chirurgi