Phase shifting speckle interferometry for dynamic phenomena.

The paper presents an algorithm able to retrieve the phase in speckle interferometry by a single intensity pattern acquired in a deformed state, provided that the integrated speckle field is resolved in the reference condition in terms of mean intensity, modulation amplitude and phase. The proposed approach, called throughout the paper "one-step", can be applied for studying phenomena whose rapid evolution does not allow the application of a standard phase-shifting procedure, which, on the other hand, must be applied at the beginning of the experiment. The approach was proved by an experimental test reported at the end of the paper

A novel operating principle in speckle interferometry: the double-focusing.

The present paper describes in details the operating principle of a completely new family of speckle interferometers: the double-focusing. This type of interferometer is sensitive to the same components of displacement given by holographic interferometry, i.e. the component along the bisector of the angle identified by the illumination and the observation directions. In addition, no external reference beam is necessary, with a consequent reduction of the complexity of the experimental setup. The only requirement for the correct functioning of this family of interferometers is that only a portion of the illuminated area undergoes a sensible deformation. The implementation can be indifferently carried out by adopting the classical Michelson or Mach-Zender configurations, but also a particularly compact in-line implementation can be realized

Multi-scale Laplacian community detection in heterogeneous networks

Heterogeneous and complex networks represent the intertwined interactions between real-world elements or agents. A fundamental problem of complex network theory involves finding inherent partitions, clusters, or communities. By taking advantage of the recent Laplacian Renormalization Group approach, we scrutinize information diffusion pathways throughout networks to shed further light on this issue. Based on inter-node communicability, our definition provides a unifying framework for multiple partitioning measures: multi-scale Laplacian (MSL) community detection algorithm. This new framework permits to introduce a scale-dependent optimal partition in communities and to determine the existence of a particular class of nodes, called metastable nodes, that switching community at different scales are expected to play a central role in the communication between different communities and, therefore in the control of the whole network.Comment: 14 pages, 12 figure

Caratterizzazione elasto-plastica mediante prove di trazione e interferometria speckle

Dottorato di Ricerca in Ingegneria dei Materiali e delle Strutture, XXIII Ciclo a.a. 2009-2010In the present work of thesis an experimental equipment for elasto-plastic characterization of engineering materials by tensile tests is presented. The stress state is imposed to the specimen by a testing machine fixed on the optical table and designed for optimizing the performance of a speckle interferometer. All three displacement components are measured by a portable speckle interferometer fed by three laser diodes of 50 mW, by which the deformations of small surfaces can be fully analyzed in details. The whole equipment is driven by control electronics designed and realized on purpose, by which it is possible to accurately modify the intensity of the illumination sources, the position of a PZT actuator necessary for applying phaseshifting procedure, and the overall displacement applied to the specimen. The experiments were carried out by a virtual instrument implemented in National Instrument LabVIEW environment, while the processing of the experimental data in Wolfram Mathematica environment. The thesis first reports some preliminary results obtained by a specimen subjected to 3D rigid body motions; the results showed a high accuracy and repeatability of the interferometer. Then, the whole experimental apparatus was employed for the elasto-plastic characterization of a high strength steel specimen. The σ-ε curve for the material was determined and the experimental data were approximated using Ramberg-Osgood and Hollomon’s constitutive models.Università della Calabri

Targeting GLI1 and GLI2 with small molecule inhibitors to suppress GLI-dependent transcription and tumor growth

Aberrant activation of Hedgehog (HH) signaling in cancer is the result of genetic alterations of upstream pathway components (canonical) or other oncogenic mechanisms (noncanonical), that ultimately concur to activate the zinc-finger transcription factors GLI1 and GLI2. Therefore, inhibition of GLI activity is a good therapeutic option to suppress both canonical and noncanonical activation of the HH pathway. However, only a few GLI inhibitors are available, and none of them have the profile required for clinical development due to poor metabolic stability and aqueous solubility, and high hydrophobicity. Two promising quinoline inhibitors of GLI were selected by virtual screening and subjected to hit-to-lead optimization, thus leading to the identification of the 4-methoxy-8-hydroxyquinoline derivative JC19. This molecule impaired GLI1 and GLI2 activities in several cellular models interfering with the binding of GLI1 and GLI2 to DNA. JC19 suppressed cancer cell proliferation by enhancing apoptosis, inducing a strong anti-tumor response in several cancer cell lines in vitro. Specificity towards GLI1 and GLI2 was demonstrated by lower activity of JC19 in GLI1- or GLI2-depleted cancer cells. JC19 showed excellent metabolic stability and high passive permeability. Notably, JC19 inhibited GLI1-dependent melanoma xenograft growth in vivo, with no evidence of toxic effects in mice. These results highlight the potential of JC19 as a novel anti-cancer agent targeting GLI1 and GLI2