471 research outputs found
Multilayer stag beetle elytra perform better under external loading via non-symmetric bending properties
FEM images showing the von-Mises stress distribution (unit of measure GPa) in the wing and the beetle body under a concentrated load of 0.5 N .A) real structure with void, B) elytra with no void
Axial Load Variation of Columns in Symmetrical RC Buildings Subject to Bidirectional Lateral Actions in Regions of Low to Moderate Seismicity
Columns in building frame systems are subjected to the combined action of bidirectional horizontal loading and axial load variation during an earthquake. Whilst the behaviour of RC columns under unidirectional and bidirectional lateral loading with constant axial load is understood well, the behaviour under bidirectional lateral loading with axial load variation is rarely studied, especially for limited ductile RC columns prevalent in regions of low to moderate seismicity. This paper begins with a numerical study that aims to obtain the generalised patterns and range of axial load variation in RC building columns. To this end, a case study building is subjected to a suite of 15 ground motions, representative of low to moderate seismic regions, in OpenSees. This is followed by an experimental study in which limited ductile high-strength RC columns are tested under bidirectional lateral loading and two different axial load variation protocols, namely synchronous and nonsynchronous variable axial loading protocols. The results of the numerical study demonstrated that axial load variation of the columns in an RC building is primarily dependent on the response spectral acceleration corresponding to the fundamental period of the structure in the two orthogonal horizontal directions and/or the vertical direction. The results of the experimental testing showed that nonsynchronous axial loading (compared to constant and synchronous axial loading) results in the lowest collapse drift capacity and energy dissipation of the RC columns.</p
A new vertebrate for Europe: the discovery of a range-restricted relict viper in the western Italian Alps
We describe Vipera walser, a new viper species from the north-western Italian Alps. Despite an overall morphological resemblance with Vipera berus, the new species is remarkably distinct genetically from both V. berus and other vipers occurring in western Europe and shows closer affinities to species occurring only in the Caucasus. Morphologically, the new species appear to be more similar to V. berus than to its closest relatives occurring in the Caucasus, but can be readily distinguished in most cases by a combination of meristic features as confirmed by discriminant analysis. The extant population shows a very low genetic variability measured with mitochondrial markers, suggesting that the taxon has suffered a serious population reduction/bottleneck in the past. The species is extremely range-restricted (less than 500 km2) and occurs only in two disjunct sites within the high rainfall valleys of the Alps north of Biella. This new species should be classified as globally ‘endangered’ due to its small and fragmented range, and an inferred population decline. The main near-future threats to the species are habitat changes associated with reduced grazing, along with persecution and collecting
Shifting paradigms in two common abdominal surgical emergencies during the pandemic
During the pandemic there was a reduction in access to the hospital and surgical treatment of appendicitis and cholecystitis at a global level. Some strategies adopted during this challenging time could be applied even after the emergency has been controlled
Assessing marine ecosystem services richness and exposure to anthropogenic threats in small sea areas: A case study for the Lithuanian sea space
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThe Lithuanian sea space belongs to the smallest sea areas in Europe. The sea space incorporates multiple marine ecosystem services (MES) that support human-wellbeing and sustain maritime economies, but is also subjected to intensive anthropogenic activities that can affect its vulnerable ecological components. We present a flexible geospatial methodology to assess MES richness (MESR) and to analyse areas of exposure of MES to human impacts using a MES exposure index (MESEx). Source of anthropogenic threats to MES were firstly derived from the Marine Strategy Framework Directive and include marine litter (from ports and shipping), underwater noise (from offshore pile driving and shipping) and hazardous substances (from oil extraction platforms). Results were presented for the three main planning areas in Lithuania, the Lithuanian Coastal Stripe, territorial waters and EEZ. In detail, areas of highest MESR are located in the coastal areas of the Lithuanian Mainland Coast that are particularly rich in ecosystem services such as nursery function from for Baltic Herring and cultural services related to valuable recreational resorts, landscape aesthetic values and natural heritage sites. Modelled pressure exposure on selected MES show that cultural ecosystem services in proximity of Klaipėda Port can be particularly affected by marine litter accumulation phenomena, while transboundary effects of potential oil spills from D6-Platform (Kaliningrad Region) can affect valuable fish provisioning areas and coastal cultural values in the Curonian Spit. Results were discussed for the relevance in MES assessment for marine spatial planning in small sea areas and the methodological outlook of the application of geospatial techniques on cumulative impacts assessment within this region of the Baltic Sea
A case of Plasmodium malariae recurrence: Recrudescence or reinfection?
Background: Plasmodium malariae is the most neglected of the six human malaria species and it is still unknown which is the mechanism underlying the long latency of this Plasmodium. Case presentation: A case of PCR-confirmed P. malariae recurrence in a 52-year old Italian man was observed 5 months after a primary attack. In the interval between the two observed episodes of malaria the patient denied any further stay in endemic areas except for a visit to Libya, a country considered malaria-free. Genomic DNA of the P. malariae strain using five microsatellites (PM2, PM9, PM11, PM25, PM34) and the antigen marker of circumsporozoite (csp) was amplified and sequenced. Analysis of polymorphisms of the P. malariae csp central repeat region showed differences between the strains responsible of the first and second episode of malaria. A difference in the allele size was also observed for the sequence analysis of PM2 microsatellites. Conclusions: Plasmodium malariae is a challenging human malaria parasite and even with the use of molecular techniques the pathogenesis of recurrent episodes cannot be precisely explained
A low-cost prototype for monitoring the fermentation of must: initial laboratory-scale tests
A relevant aspect of modern viticulture and the wine-making process is to ensure a good quality control by a correct handling of the alcoholic fermentation. Currently, there are systems available on the market that can assist the winemaker in feeding the yeast during the fermentation process according to predetermined nutrient profiles. To optimise this operation and improve nutrient dosing, an objective evaluation of quality parameters related to the various phases of the fermentation process (i.e., TSS, density and developed alcohol) is required.
In this context, this work aims to design, build, and test a monitoring system using optical Vis/NIR sensors. A first prototype version was developed and used for laboratory-scale measurements to evaluate a simulated red grape fermentation process. The module was designed and built using 3D resin printers. It was equipped with a halogen lamp (20W, 12V, MR11) and a cooling system controlled by a microcontroller (Arduino Nano). Spectral measurements were performed using two ultra-compact spectrometric heads that detect optical signals from 340 nm to 850 nm (Hamamatsu, C12880MA) and from 640 nm to 1050 nm (Hamamatsu, C14384MA-01), respectively.
The result showed a good predictive performance (evaluated in cross-validation) with an RPD equal to 8.9. This sensing architecture will be combined and/or used in cooperation with chemical/physical sensors (temperature, pressure, CO2, etc.) to develop a real-time multi-parameter system to be used as a PAT in yeast feeding machines to develop a quality-by-design approach for oenology 4.0
Structural setting of a transpressive shear zone: Insights from geological mapping, quartz petrofabric and kinematic vorticity analysis in NE Sardinia (Italy)
The Posada-Asinara Line is a crustal-scale transpressive shear zone affecting the Variscan basement in northern Sardinia during Late Carboniferous time. We investigated a structural transect of the Posada-Asinara Line (Baronie) with the aid of geological mapping and structural analysis. N-verging F2 isoclinal folds with associated mylonitic foliation (S2) are the main deformation features developed during the Posada-Asinara Line activity (D2). The mineral assemblages and microstructures suggest that the Posada-Asinara Line was affected by a retrograde metamorphic path. This is also confirmed by quartz microstructures, where subgrain rotation recrystallization superimposes on grain boundary migration recrystallization. Crystallographic preferred orientation data, obtained using electron backscatter diffraction, allowed analysis of quartz slip systems and estimation of the deformation temperature, vorticity of flow and rheological parameters (flow stress and strain rate) during the Posada-Asinara Line activity. Quartz deformation temperatures of 400 ± 50 °C have been estimated along a transect perpendicular to the Posada-Asinara Line, in agreement with the syn-kinematic post-metamorphic peak mineral assemblages and the late microstructures of quartz. The D2 phase can be subdivided in two events: an early D2early phase, related to the metamorphic peak and low kinematic vorticity (pure shear dominated), and a late D2late phase characterized by a lower metamorphic grade and an increased kinematic vorticity (simple shear dominated). Palaeopiezometry and strain rate estimates associated with the D2late deformation event showed an intensity gradient increasing towards the core of the shear zone. The D2early deformation developed under peak temperature conditions, while the D2late event was active at shallower structural levels
The earthquake cycle in the dry lower continental crust: insights from two deeply exhumed terranes (Musgrave Ranges, Australia and Lofoten, Norway)
This paper discusses the results of field-based geological investigations of exhumed rocks exposed in the Musgrave Ranges (Central Australia) and in Nusfjord (Lofoten, Norway) that preserve evidence for lower continental crustal earthquakes with focal depths of approximately 25–40 km. These studies have established that deformation of the dry lower continental crust is characterized by a cyclic interplay between viscous creep (mylonitization) and brittle, seismic slip associated with the formation of pseudotachylytes (a solidified melt produced during seismic slip along a fault in silicate rocks). Seismic slip triggers rheological weakening and a transition to viscous creep, which may be already active during the immediate post-seismic deformation along faults initially characterized by frictional melting and wall-rock damage. The cyclical interplay between seismic slip and viscous creep implies transient oscillations in stress and strain rate, which are preserved in the shear zone microstructure. In both localities, the spatial distribution of pseudotachylytes is consistent with a local (deep) source for the transient high stresses required to generate earthquakes in the lower crust. This deep source is the result of localized stress amplification in dry and strong materials generated at the contacts with ductile shear zones, producing multiple generations of pseudotachylyte over geological time. This implies that both the short- and the long-term rheological evolution of the dry lower crust typical of continental interiors is controlled by earthquake cycle deformation. This article is part of a discussion meeting issue ‘Understanding earthquakes using the geological record’.</jats:p
Identification of Isoform 2 Acid-Sensing Ion Channel Inhibitors as Tool Compounds for Target Validation Studies in CNS
Acid-sensing ion channels (ASICs) are a family of ion channels permeable to cations and largely responsible for the onset of acid-evoked ion currents both in neurons and in different types of cancer cells, thus representing a potential target for drug discovery. Owing to the limited attention ASIC2 has received so far, an exploratory program was initiated to identify ASIC2 inhibitors using diminazene, a known pan-ASIC inhibitor, as a chemical starting point for structural elaboration. The performed exploration enabled the identification of a novel series of ASIC2 inhibitors. In particular, compound 2u is a brain penetrant ASIC2 inhibitor endowed with an optimal pharmacokinetic profile. This compound may represent a useful tool to validate in animal models in vivo the role of ASIC2 in different neurodegenerative central nervous system pathologies
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