A New Ultrasonic Immersion Technique for the Evaluation of Damage Induced Anisotropy in Composite Materials

We present a theoretical and experimental approach for the characterization of the damage induced anisotropy superimposed to the constitutive anisotropy of fiber-reinforced composite materials. The proposed theoretical model has been developed in the framework of the Continuum Damage Mechanics theory and allows for determining a tensorial damage measure based on the change of the elastic moduli of the composite material. Moreover, the model is general since it is applicable independently of the fibers reinforcement nature, of the presence of cracks, interlaminar voids and delamination, of the geometry of this cracks, and from of failure mechanisms of the composite materials. We perform damage experiments by employing an innovative goniometric device designed and built at our laboratory (Laboratorio “M. Salvati”), and aimed at the mechanical characterization of materials. In particular, by rotating the sample into a water tank, we measure the ultrasonic “natural” velocities of the undamaged composite material along suitable propagation directions. This allow us for classifying the degree of symmetry of the material and for determining the elastic constants, also in highly anisotropic materials. Then we measure the ultrasonic velocities of the artificially damaged composite and we determine again the elastic moduli. The comparison between the elastic moduli of the damaged and the undamaged composite allows us for the characterization of the anisotropic tensorial damage measure

Self-Equilibrium state of V-Expander Tensegrity Beam

In this paper, we study an innovative class of tensegrity beams, obtained by a suitable assembly of elementary V-Expander tensegrity cells along a longitudinal axis in the three-dimensional space. Tensegrity structures, made by struts in compression and cables in tension, are an innovative structures by itself: they are similar only in appearance to conventional pin-joint structures (trusses), and their mechanics is strongly related to initial feasible self-stress states induced in absence of external loads. In particular, from a kinematical point of view these self-stress states avoid the activation of possible infinitesimal mechanisms. By a numerical study, we analyze the feasible self-stress states for lightweight tensegrity beams made by a suitable assembly of V-Expander elementary cells. Moreover, we analyze the influence on the feasible self-stress states of the addition of struts or cables starting from the simplest V-Expander configuration

leaf appearance rate and final main stem leaf number as affected by temperature and photoperiod in cereals grown in mediterranean environment

In the present study, a two-year field trial was carried out with the aim to evaluate daylength and air temperature effects on leaf appearance and related rates in two durum wheat (Triticum durum Desf.), two bread wheat (Triticum aestivum L.) and two barley (Hordeum vulgare L.) cultivars, using six different sowing dates (SD). Significant effects of SD on final main stem leaf number (FLN), thermal leaf appearance rate (TLAR), daily leaf appearance rate (DLAR) and phyllochron (PhL) were found. Cultivars resulted inversely correlated to mean air temperature in the interval emergence - fifth leaf full expansion (E-V). Linear response of leaf number over days after sowing was shown for all SD and cultivars, with R2 higher than 0.95. FLN linearly decreased from the first to the last SD for durum wheat, while more variable behaviour was observed in bread wheat. TLAR and DLAR showed a linear increment of the rate from the first to the last SD in durum wheat, while did not for bread wheat and barley. PhL in durum wheat decreased from the first to the last SD. Barley and bread wheat showed the highest values on those SDs which did not reach flowering. The increase of TLAR was affected by photoperiod and photothermal units in durum wheat, while by temperatures only in barley and bread wheat. Present results might find practical application in the improvement of phenology simulation models for durum wheat, bread wheat and barley grown in Mediterranean area in absence of water and nutrient stress

Enhancing grain size in durum wheat using RNAi to knockdown GW2 genes

Sestili F., Pagliarello R., Zega A., Saletti R., Pucci A., Botticella E., Masci S., Tundo S., Moscetti I., Foti S., Lafiandra D. 2019 Enhancing grain size in durum wheat using RNAi to knock-down GW2 genes. Theoretical and Applied Genetics, 132(2): 419-429 https://doi.org/10.1007/s00122-018-3229-9. Abstract Key message Knocking down GW2 enhances grain size by regulating genes encoding the synthesis of cytokinin, gibberellin, starch and cell wall. Abstract Raising crop yield is a priority task in the light of the continuing growth of the world’s population and the inexorable loss of arable land to urbanization. Here, the RNAi approach was taken to reduce the abundance of Grain Weight 2 (GW2) transcript in the durum wheat cultivar Svevo. The effect of the knockdown was to increase the grains’ starch content by 10–40%, their width by 4–13% and their surface area by 3–5%. Transcriptomic profiling, based on a quantitative real-time PCR platform, revealed that the transcript abundance of genes encoding both cytokinin dehydrogenase 1 and the large subunit of ADP-glucose pyrophosphorylase was markedly increased in the transgenic lines, whereas that of the genes encoding cytokinin dehydrogenase 2 and gibberellin 3-oxidase was reduced. A proteomic analysis of the non-storage fraction extracted from mature grains detected that eleven proteins were differentially represented in the transgenic compared to wild-type grain: some of these were involved, or at least potentially involved, in cell wall development, suggesting a role of GW2 in the regulation of cell division in the wheat grain

'Omics' and chemical approaches used to monitor iron-deficiency in citrus rootstocks

Two different 'omics' approaches were performed to a better comprehension of biological mechanisms involved in citrus iron (Fe) deficiency. Tips roots from Swingle citrumelo and Carrizo citrange (sensitive and tolerant rootstocks, respectively), growing in pots with control and chlorotic soil, were used for transcriptomic and proteomic analysis. CombiMatrix array was performed to isolate differential genes, among which glutathione peroxidase (GPX), SAUR gene and glutamate dehydrogenase (GDH) showed to be the most involved ones. They were switched on Swingle grown on calcareous conditions compared to Carrizo (in the same soil) and to the same stock in the control soil. The over-expression of GPX could be the effort of plants to neutralize the oxidative environment produced by stress. The involvement of auxin (and as consequence of SAUR gene) in the regulation of Fe deficiency responses is also well known. Both genes were considered in association to peroxidase, ferric chelate reductase activities, iron and chlorophyll content, to monitor the degree of suffering of rootstocks. Among differentially expressed proteins, identified by means of 2D-PAGE and RP-HPLC/nESI-MSMS, a strong down-regulation of cytosolic pyrophosphate-dependent phosphofructokinase β-subunit and NADPH-isocitrate dehydrogenase could produce plant inability to sustain the energetic request of cell roots

Radiation Macular Edema after Ru-106 Plaque Brachytherapy for Choroidal Melanoma Resolved by an Intravitreal Dexamethasone 0.7-mg Implant

Purpose: To report the effective treatment of radiation macular edema following ruthenium-106 plaque brachytherapy for a choroidal melanoma with a dexamethasone 0.7-mg (Ozurdex®) intravitreal implant. Methods: An interventional case report with optical coherence tomography (OCT) scans. Results: A 65-year-old Caucasian woman was suffering from radiation macular edema following ruthenium-106 plaque brachytherapy for a choroidal melanoma on her left eye. She had undergone one intravitreal injection of 0.5 mg bevacizumab (Avastin®, Genentech/Roche) in the following months without functional or anatomical improvement. Seven months after the development of radiation macular edema, she received a single intravitreal injection of dexamethasone 0.7 mg (Ozurdex). Four weeks following the injection, her best-corrected visual acuity improved from 0.3 to 0.5. Radiation macular edema resolved with a reduction of central retinal thickness from 498 µm before Ozurdex injection to 224 µm after Ozurdex injection, as measured by OCT scan. Conclusion: Dexamethasone 0.7 mg (Ozurdex) has proven to be an effective treatment option in retinal vein occlusion and noninfectious uveitis. It can also be considered as off-label treatment in radiation macular edema following ruthenium-106 plaque brachytherapy for a choroidal melanoma

Proximity remote sensing : preliminary results at the Batia Church (Tortorici, Sicily)

The paper presents the results of scientific investigations carried out at the Batia Church located in the small village of Tortorici (Messina, Sicily). We performed several geophysical surveys and reconstruct 2D and 3D digital models of the monument using digital photogrammetry. From the 3D model accurate digital elevation models. A detail mapping was carried out using the derived 3D digital model identifying mayor fractures as well as quantifying the extent of original pain and the modern interventions.peer-reviewe

Using geomatics and geophysics to study underground anthropogenic water systems : the UAW project

This paper presents some preliminary results of the scientific investigations carried out at underground water channels located on Mounts Nebrodi in Sicily (Southern Italy). We performed several geophysical surveys as well as geomatics approaches were used in order to reconstruct 2D and 3D digital models of this underground monuments. N here, we also present the potential of valorizing these cultural heritage sites and its underground structures by the means of advanced technologies and digital reconstructions.peer-reviewe