Giuseppe Lombardo

New evidence of wavefield polarization on fault zone in the lower NE slope of Mt. Etna

Fault zones are generally characterized by a damage zone, formed by highly fractured materials, that is seismically characterized by low velocity and rigidity compared to the host rock. Such geometrical setting, coupled with impedance contrast, lead to the development of local amplification of the ground motion and directional effects. In the present study, the results of measurements performed in the lower north-eastern area of Mt. Etna are shown and discussed. Ambient noise data were recorded and processed through the horizontal to vertical spectral ratio technique, setting into evidence directional effects and providing a direct estimate of the polarization angle as well. The data were recorded along and across the Piedimonte-Fiumefreddo fault system, a set of NE-SW trending extensional segmented faults, that is flanked by small conjugate segments and is accompanied by several WNW-ESE oriented minor faults and fractures of the Pernicana fault system.Results point out that in most of the investigated sites the polarization effects are nearly perpendicular with respect to the minor faults, striking WNW-ESE. This highlight that the local extensional deformation field, related to the shear zone of the Pernicana fault system, plays an important role and it appears as the predominant one in the seismic response that characterize this tectonically complicated area.

Identification of novel targets for the diagnosis and treatment of liver fibrosis

Liver fibrosis is characterized by the excessive deposition of extracellular matrix (ECM) in the hepatic parenchyma and represents an intrinsic response to chronic injury, maintaining organ integrity when extensive necrosis or apoptosis occurs. Hepatic stellate cells (HSCs) are the major cell type responsible for liver fibrosis. Following liver injury, HSCs become activated and transdifferentiate into myofibroblasts (MFBs) that lead to intrahepatic ECM accumulation. In the present study, we performed a meta‑analysis of datasets which included whole-genome transcriptional data on HSCs in the quiescent and activated state from two different rodent species and identified commonly regulated genes. Several of the genes identified, including ECM components, metalloproteinases and growth factors, were found to be well‑known markers for HSC activation. However, other significant genes also appeared to play important roles in hepatic fibrosis. The elucidation of the molecular events underlying HSC activation may be key to the identification of potential novel pharmacological targets for the prevention and treatment of liver fibrosis.

Evaluation of building fundamental periods and effects of local geology on ground motion parameters in the Siracusa area, Italy

The Siracusa area, located in the southeastern coast of Sicily (Italy), is mainly characterized by the outcropping of a limestone formation. This lithotype, which is overlain by soft sediments such as sandy clays and detritus, can be considered as the local bedrock. Records of ambient noise, processed through spectral ratio techniques, were used to assess the dynamic properties of a sample survey of both reinforced concrete and masonry buildings. The results show that experimental periods of existing buildings are always lower than those proposed by the European seismic code. This disagreement could be related to the role played by stiff masonry infills, as well as the influence of adjacent buildings, especially in downtown Siracusa. Numerical modeling was also used to study the effect of local geology on the seismic site response of the Siracusa area. Seismic urban scenarios were simulated considering a moderate magnitude earthquake (December 13th, 1990) to assess the shaking level of the different outcropping formations. Spectral acceleration at different periods, peak ground acceleration, and velocity were obtained through a stochastic approach adopting an extended source model code. Seismic ground motion scenario highlighted that amplification mainly occurs in the sedimentary deposits that are widespread to the south of the study area as well as on some spot areas where coarse detritus and sandy clay outcrop. On the other hand, the level of shaking appears moderate in all zones with outcropping limestone and volcanics.

Features of volcanic tremors on Mt. Etna (Sicily) during the March–August 1983 eruption

The seismic analysis of the volcanic tremors preceding and accompanying the Etnean eruption of March–August, 1983 has shown a significant variation in the spectral content before the beginning of the eruption, the tremor peaks at 1.4 and 1.6 Hz — which might be associated with the feeding pipes of the NE crater (Schicket al., 1982a) — being the dominant feature of the spectra.A model of eruption mechanism is proposed where a feeder dyke would connect the NE crater with the effusive fracture.

A microtremor survey to define the subsoil structure in a mud volcanoes area: the case study of Salinelle (Mt. Etna, Italy)

Abstract A microtremor survey aiming to obtain information on subsoil structure was performed in the lower southwestern Etnean flank (Sicily, Italy). The area is characterized by emissions of muddy and salty water which create specific pseudo-volcanic edifices. Recording sites were both randomly selected in the area and along two profiles. Horizontal-to-vertical noise spectral ratio, polarization and surface wave prospecting techniques were used. The spectral ratios results set into evidence different frequency ranges that appear interesting to infer information on the subsoil structure. The depth of the hydrocarbon reservoir was inferred through 1D modeling, by using the information coming from the literature and experimental surveys. Moreover, a strongly directional effect suggests the existence of a NNW-SSE-oriented mud feeding dike.

Exploratory seismic site response surveys in a complex geologic area: a case study from Mt. Etna volcano (southern Italy)

A preliminary study targeting to evaluate the local seismic response was performed in the eastern flank of Mt. Etna (southern Italy) using ambient noise measurements. The obtained spectral ratios were subdivided through cluster analysis into different classes of fundamental frequency permitting to draw an iso-frequency contour map. The analysis set into evidence the extreme heterogeneity of lava sequences, which makes difficult to identify a single seismic bedrock formation. Another important outcome, concerning the local seismic effects in terms of frequency and azimuth, is the important role played by the fracture fields associated with the main structural systems of the area. The existence of two zones with strong directional effects striking WNW–ESE and NW–SE, nearly orthogonal to the orientation of the main fracture fields, corroborate such hypothesis.

Reconstruction of a Nose Bitten and Eaten by a Dog: A Ten-Year Follow-up of a Bitten-Off Nose Replantation Performed on an Eleven-Year-Old Boy.

The nose is one of the most important aesthetic units of the face. After a traumatic amputation, replantation is undoubtedly the procedure of choice, although, technically, very challenging. We report the 10-year follow-up of a partially digested nose replantation after a dog-bite in an 11-year-old boy using supermicrosurgery technique. Our report confirms that the microsurgical replantation of the nose can lead to an acceptable aesthetic result, with the sufficient growth of the replanted part in the following years. Besides the patient did not report sensibility disorders. The nose replantation in our opinion is the best reconstructive option to achieve an optimal aesthetic and functional outcome.

Effects of NO-Hybridization on the Immunomodulatory Properties of the HIV Protease Inhibitors Lopinavir and Ritonavir

HIV protease inhibitors (PIs) are antiretroviral agents, which have been found to also affect several cellular processes, such as inflammation and cell progression. In studies on non‐steroidal, anti‐inflammatory drugs, the addition of a nitric oxide (NO) moiety has been shown to both reduce their toxicity and enhance their pharmacological efficacy. Along this line of research, several derivatives of PIs have been synthesized by covalent attachment of NO moiety to the parental molecules. Previous work has indicated that NO‐hybridization of the prototypical PI, Saquinavir leads to a derivative named Saquinavir‐NO that while retaining the antiretroviral effect, acquires antitumoural and immunomodulatory properties along with reduced toxicity in vitro and in vivo. These data prompted us to evaluate the effects of NO‐hybridization on two other PIs, Lopinavir and Ritonavir. The two NO‐derivatives were compared head to head with their parental compounds on human primary peripheral blood mononuclear cells as well as on human primary macrophages. Lopinavir‐NO and Lopinavir were also screened in an in vivo model of autoimmune hepatitis. Our results prove that Lopinavir‐NO exerts markedly superior effects as compared to the parental compound both in vitro and in vivo. On the contrary, Ritonavir‐NO effects overlapped those of Ritonavir. These data demonstrate that NO‐hybridization of Lopinavir generates a derivative with significantly stronger immunomodulatory effects that are apparently related to an action of the compound on T‐cell secretory capacity. Lopinavir‐NO deserves additional studies for its possible use in T‐cell‐mediated autoimmune diseases including, but not limited to autoimmune hepatitis.

A model for eruptive mechanisms of Mt. Etna from the study of seismicity from 1978 to 1983

The papers deals with the seismic activity occurred on Mt. Etna from 1978 to 1983, and special emphasis is given to the seismicity linked to eruptive phenomena that took place during that period.Location of epicentres and hypocentres of all earthquakes occurred during the considered years and in association with each eruption has shown to be a useful tool to investigate relationships between seismicity and characteristics of various eruptions.A preliminary model is proposed to explain seismo-eruptive mechanisms controlling the uprise of magma and subsequent eruptions of Mt. Etna. The complexity of phenomena observed in the Etnean area could be interpreted as the result of the combined effect of regional stress field and local changes of it due to the volcano structural inhomogeneities. Thus, the earthquakes occurring in the studied area may cause either partial intrusion of magma at various depth, or final opening of surface fractures and subsequent output of lava.

Evaluation Of The Local Seismic Response In TheArea Of Catania (Italy)

The evaluation of seismic site response in the urban area of Catania was tackled by selecting test areas having peculiar lithological and structural features, potentially favourable to large local amplifications of ground motion. The two selected areas are located in the historical downtown and in the northern part of Catania where the presence of a fault is evident. Site response was evaluated using a spectral ratio technique taking the horizontal-to-vertical component ratio of ambient noise. Inference from microtremor measurements are compared with results from synthetic accelerograms and response spectra computed at all drillings available for this area. The microtremor H/V spectral ratios evaluated at soft sites located within the downtown profile tend to be smaller than that usually reported in the literature for such soils. A tendency for amplifications to peaks near 2 Hz is observed only in some sites located on recent alluvial deposits. Evidence for amplifications of site effects (frequency range 4-8 Hz) were observed in the sampling sites located on the fault, with a rapid decrease of spectral amplitude just a few tenths of a meter away from the discontinuity. Numerical simulations evidenced the importance of geolithological features at depth levels even greater than 20-30 m. Besides this, the results strongly confirm the importance of the subsurface geological conditions in the estimate of seismic hazard on urban scales.