Wave extreme characterization using self-organizing maps

Abstract. The self-organizing map (SOM) technique is considered and extended to assess the extremes of a multivariate sea wave climate at a site. The main purpose is to obtain a more complete representation of the sea states, including the most severe states that otherwise would be missed by a SOM. Indeed, it is commonly recognized, and herein confirmed, that a SOM is a good regressor of a sample if the frequency of events is high (e.g., for low/moderate sea states), while a SOM fails if the frequency is low (e.g., for the most severe sea states). Therefore, we have considered a trivariate wave climate (composed by significant wave height, mean wave period and mean wave direction) collected continuously at the Acqua Alta oceanographic tower (northern Adriatic Sea, Italy) during the period 1979–2008. Three different strategies derived by SOM have been tested in order to capture the most extreme events. The first contemplates a pre-processing of the input data set aimed at reducing redundancies; the second, based on the post-processing of SOM outputs, consists in a two-step SOM where the first step is applied to the original data set, and the second step is applied on the events exceeding a given threshold. A complete graphical representation of the outcomes of a two-step SOM is proposed. Results suggest that the post-processing strategy is more effective than the pre-processing one in order to represent the wave climate extremes. An application of the proposed two-step approach is also provided, showing that a proper representation of the extreme wave climate leads to enhanced quantification of, for instance, the alongshore component of the wave energy flux in shallow water. Finally, the third strategy focuses on the peaks of the storms

Sediment transport modifications induced by submerged artificial reef systems: a case study for the Gulf of Venice

Abstract The shallow, gently sloping, sandy-silty seabed of the Venetian coast (Italy) is studded by a number of outcropping rocky systems of different size encouraging the development of peculiar zoobenthic biocenoses with considerably higher biodiversity indexes compared to neighbouring areas. In order to protect and enhance the growth of settling communities, artificial monolithic reefs were deployed close to the most important formations, providing further nesting sites and mechanical hindrance to illegal trawl fishing. In this framework, a multi-step and multi-scale numerical modelling activity was carried out to predict the perturbations induced by the presence of artificial structures on sediment transport over the outcroppings and their implications on turbidity and water quality. After having characterized wave and current circulation climate at the sub-basin scale over a reference year, a set of small scale simulations was carried out to describe the effects of a single monolith under different geometries and hydrodynamic forcings, encompassing the conditions likely occurring at the study sites. A dedicated tool was then developed to compose the information contained in the small-scale database into realistic deployment configurations, and applied in four protected outcroppings identified as test sites. With reference to these cases, under current meteomarine climate the application highlighted a small and localised increase in suspended sediment concentration, suggesting that the implemented deployment strategy is not likely to produce harmful effects on turbidity close to the outcroppings. In a broader context, the activity is oriented at the tuning of a flexible instrument for supporting the decision-making process in benthic environments of outstanding environmental relevance, especially in the Integrated Coastal Zone Management or Maritime Spatial Planning applications. The dissemination of sub-basin scale modelling results via the THREDDS Data Server, together with an user-friendly software for composing single-monolith runs and a graphical interface for exploring the available data, significantly improves the quantitative information collection and sharing among scientists, stakeholders and policy-makers

Melatonin effects in normal and tumoral skeletal muscle cells: a preliminary study

Melatonin (MEL), also chemically known as N-acetyl-5-methoxytryptamine, is a hormone found in animals, plants, and microbes. It exhibits strong antioxidant effects and thanks to its structure it is able to diffuse through all the biological membranes, also overcoming the blood-brain barrier and the placenta (Salucci et al., 2014). Numerous in vitro and in vivo studies have documented Mel ability to induce apoptosis in tumor cells while inhibiting it in the normal ones (Cristofanos et al, 2009; Lanoix et al., 2011). In this study MEL activity has been investigated in vitro both in murine skeletal muscle (C2C12) and in alveolar rhabdomyosarcoma (RH30) cell lines by means of morpho-functional approaches. If MEL low concentrations are well tolerated by normal skeletal muscle cells, its effect appears completely different in tumor cells, where MEL can be considered a powerful apoptotic trigger. In RH30 cells, blebbing, chromatin condensation and margination, apoptotic bodies occur as well as necrotic cell death features. The latter appeared after prolonged exposure to MEL. In conclusion, the neuro-hormone shows a strong dose and time dependent pro-apoptotic activity and it could represent a potential tool in association with the current chemotherapeutic compounds to resolve alveolar rhabdomyosarcoma, the most common pediatric skeletal muscle tissue malignancy

Tyrosol antioxidant effect in C2C12 cell line

Tyrosol (4-(2-hydroxyethyl) phenol) (Tyr) is a well-known phenolic compound that is mainly present in extra-virgin olive oil and white wine. It has many beneficial properties, such as antioxidant, antimicrobial and anti-inflammatory activity and has been reported to have scavenging effects on peroxynitrite and superoxide anion (1). Moreover, Tyr exhibits anticancer, anti-depressant, anti-stress, cardioprotective, antiosteoporosis, anti-inflammatory and neural protective effects (2). Here Tyr effect has been investigated in a skeletal muscle cell line exposed to known oxidative stress inducers (3, 4). To evaluate Tyr protection against oxidative stress and cell death, ultrastructural and functional analyses have been carried out. In particular, mitochondrial probes used and analysed at confocal microscopy. All techniques confirmed that Tyr is able to prevent skeletal muscle damage, to preserve mitochondrial membrane integrity and to down regulate oxidative stress levels. These findings demonstrated Tyr antioxidant property in skeletal muscle cell too, suggesting, for this molecule, an important potential role in all muscle diseases related to reactive oxygen species production

Patrones de dispersión y conectividad en el mar Adriático.

Comprender los procesos que controlan la dispersión y cómo la conectividad influye en la dinámica poblacional es un desafío crucial en la predicción de la distribución biogeográfica de las especies y la viabilidad de las medidas de conservación en una determinada región (Cowen et al., 2006). Recientemente, el uso de algoritmos lagrangianos acoplados a modelos numéricos ha permitido determinar las trayectorias y conectividad de partículas virtuales que emulan larvas u otros organismos entre distintas subáreas por la advección de las corrientes. Este estudio emplea dicho método para investigar los procesos hidrodinámicos que afectan a la conectividad y dispersión de larvas virtuales en el Mar Adriático, una cuenca semicerrada del Mar Mediterráneo cuya dinámica está altamente influenciada por las corrientes costeras y el intercambio de agua a través del Estrecho de Otranto.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Morphological study of cartilage cell death in patients affected by osteoarthritis and chondrocalcinosis

The role of chondrocyte death in the pathogenesis of osteoarthritis (OA) has been largely discussed in literature, but its relative contribution is difficult to assess (1). Chondrocyte death, be it apoptotic, necrotic or chondroptotic, has been clearly documented in OA and a certain correlation between the degree of cartilage damage and chondrocyte apoptosis has been demonstrated (2;3). Conversely, the relationship between the different types of cell death and chondrocalcinosis (CC) is still little known, as well as the presence and role of chondroptotic cells. The aim of this research was to compare chondrocyte behavior in the cartilage of osteoarthritic and chondrocalcinotic knees, evaluating the different types of cell death by means of optical and electron microscopy. During total knee replacement surgeries, cartilage specimens of femoral condyle have been withdrawn and their transversal semithin sections, stained with toluidine blue and alizarin solutions, have been investigated by optical microscopy. From the same samples, thin sections were obtained for transmission electron microscopy to evaluate, at high magnification, the specific ultrastructural features of different types of cell death. Cartilage specimens from both conditions revealed a thickness reduction of superficial layer and a high number of empty lacunae in the middle layer. Calcium pyrophosphate crystals appeared in the samples of patients affected by CC. In osteoarthritic cartilage, numerous chondrocytes revealed necrotic features, whereas, in chondrocalcinotic tissue, the middle zone was characterized by morphological patterns suggestive of chondroptosis, such as chromatin condensation mostly localized at the nuclear periphery, mitochondria alterations, a marked increase in endoplasmic reticulum, the presence of a diffuse autophagic component and the extrusion of cellular material into the lacunae. In conclusion, a different distribution of cell death types seems to characterize the intermediate layers of cartilage specimens from patients affected by CC compared to OA

Protein supplementation prevents etoposide-induced skeletal muscle damage

Autophagy represents a physiological mechanism responsible for cell homeostasis and its deregulation is involved in several conditions related to muscle mass loss such as aging, inflammatory diseases and disuse [1]. In our previous work, double membrane vesicles, suggestive of autophagy, appeared after chemotherapeutic treatments in C2C12 myotubes [2]. Here, skeletal muscle cells have been exposed to Etoposide (Eto), a cell-death and oxidative stress inducer, as well as to protein supplementation before the trigger. Cytofluorimetric, morphological and molecular analyses revealed that Eto treatment increases cardiolipin peroxidation events, and induces lysosomal compartment and endoplasmic reticulum damage. Moreover, a peculiar accumulation of autophagic complex vacuoles resulted in LC3 localization into dot cytoplasmic structures, appeared in treated-differentiated cells, if compared to the diffuse cytoplasmic distribution observed in untreated cells. Protein supplementation, is able to prevent myotube damage, by reducing oxidative stress, improving the lysosomal degradation pathway, and, finally, by reactivating the protein synthesis. These findings suggest that a diet rich in protein could prevent the impaired autophagic degradation in a skeletal muscle model in vitro, exposed to a chemotherapeutic agent, thus contributing to delay the progression of several muscle disorders [3]

Melatonin effects in normal and tumoral skeletal muscle cells: a preliminary study

Melatonin (MEL), also chemically known as N-acetyl-5-methoxytryptamine, is a hormone found in animals, plants, and microbes. It exhibits strong antioxidant effects and thanks to its structure it is able to diffuse through all the biological membranes, also overcoming the blood-brain barrier and the placenta (Salucci et al., 2014). Numerous in vitro and in vivo studies have documented Mel ability to induce apoptosis in tumor cells while inhibiting it in the normal ones (Cristofanos et al, 2009; Lanoix et al., 2011). In this study MEL activity has been investigated in vitro both in murine skeletal muscle (C2C12) and in alveolar rhabdomyosarcoma (RH30) cell lines by means of morpho-functional approaches. If MEL low concentrations are well tolerated by normal skeletal muscle cells, its effect appears completely different in tumor cells, where MEL can be considered a powerful apoptotic trigger. In RH30 cells, blebbing, chromatin condensation and margination, apoptotic bodies occur as well as necrotic cell death features. The latter appeared after prolonged exposure to MEL. In conclusion, the neuro-hormone shows a strong dose and time dependent pro-apoptotic activity and it could represent a potential tool in association with the current chemotherapeutic compounds to resolve alveolar rhabdomyosarcoma, the most common pediatric skeletal muscle tissue malignancy

Virgin oil polyphenols prevent UVB-induced keratinocyte cell death

Food compounds, in particular hydroxytyrosol (HyT), hydroxytyrosol laurate (L-HyT) and tyrosol (Tyr), polyphenols present in virgin oil, have attracted much interest because of their potential use in new preventive, protective, and therapeutic strategies for chronic skin degenerative disorders, including erythema, inflammation and aging (Lahtz et al., 2013). In our previous studies HyT and L-HyT antiapoptotic effects, against pro-oxidant agents in different cell models, have been demonstrated (Burattini et al., 2013). Here, the potential protective actions of antioxidant compounds against UV-induced apoptosis were investigated in human keratinocytes (HaCaT). The cell line was pre-treated with antioxidants before UVB exposure and their effect evaluated by means of ultrastructural and molecular analyses. After UVB radiation typical morphological apoptotic features appeared and their significant down regulation could be observed when polyphenols were administrated before cell death induction. These data have been confirmed by molecular analyses. In fact, both intrinsic and extrinsic apoptotic pathways appeared activated after UVB radiation. When antioxidants were added to samples before cell death induction, an evident caspase activation decrease could be revealed. In conclusion, these results demonstrate that polyphenols are able to prevent in vitro apoptotic cell death in human keratinocytes exposed to UVB, encouraging their use in vivo as potential sun damagepreventing molecules

CALYPSO 2019 Cruise Report: field campaign in the Mediterranean

This cruise aimed to identify transport pathways from the surface into the interior ocean during the late winter in the Alborán sea between the Strait of Gibraltar (5°40’W) and the prime meridian. Theory and previous observations indicated that these pathways likely originated at strong fronts, such as the one that separates salty Mediterranean water and the fresher water in owing from the Atlantic. Our goal was to map such pathways and quantify their transport. Since the outcropping isopycnals at the front extend to the deepest depths during the late winter, we planned the cruise at the end of the Spring, prior to the onset of thermal stratification of the surface mixed layer.Funding was provided by the Office of Naval Research under Contract No. N000141613130