1,167 research outputs found
Toxicity of the Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) acetylsalicylic acid, paracetamol, diclofenac, ibuprofen and naproxen towards freshwater invertebrates : A review
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) represent one of the main therapeutic classes of molecules contaminating aquatic ecosystems worldwide. NSAIDs are commonly and extensively used for their analgesic, antipyretic and anti-inflammatory properties to cure pain and inflammation in human and veterinary therapy. After use, NSAIDs are excreted in their native form or as metabolites, entering the aquatic ecosystems. A number of monitoring surveys has detected the presence of different NSAIDs in freshwater ecosystems in the ng/L - \u3bcg/L concentration range. Although the concentrations of NSAIDs in surface waters are low, the high biological activity of these molecules may confer them a potential toxicity towards non-target aquatic organisms. The present review aims at summarizing toxicity, in terms of both acute and chronic toxicity, induced by the main NSAIDs detected in surface waters worldwide, namely acetylsalicylic acid (ASA), paracetamol (PCM), diclofenac (DCF), ibuprofen (IBU) and naproxen (NPX), both singularly and in mixture, towards freshwater invertebrates. Invertebrates play a crucial role in ecosystem functioning so that NSAIDs-induced effects may result in hazardous consequences to the whole freshwater trophic chain. Acute toxicity of NSAIDs occurs only at high, unrealistic concentrations, while sub-lethal effects arise also at low, environmentally relevant concentrations of all these drugs. Thus, further studies represent a priority in order to improve the knowledge on NSAID toxicity and mechanism(s) of action in freshwater organisms and to shed light on their real ecological hazard towards freshwater communities
Earthworm as an alternative protein source in poultry and fish farming : Current applications and future perspectives
Among the different agricultural activities, the livestock is one of the most impacting on the environment. The feeding of animals is often the main responsible of the adverse environmental impact related to animal productions. Above all for intensive production, the consumption of protein feed is a key aspect for the achievement of sustainable production processes. The actual consumption of soybean meal and fish meal is not sustainable due to the related environmental impact and to the increasing prices. Among the different alternative protein sources, in the last 20 years, the attention of research centres and private companies focused on insects, algae and other invertebrates but, up to now, little consideration was paid to the use of fresh earthworm or earthworm meal as a protein feed for monogastric animals. The use of earthworms as an alternative protein source for fish and poultry feeding is an opportunity for providing environmental services via cleaner technologies. Thanks to earthworms, organic wastes and by-products generated by livestock activities can be valorised and become a resource for animal feeding in a circular perspective. In this context, this manuscript was designed to summarize the productivity, suitability and effectiveness issues connected with the utilization of earthworms as alternative protein feed in poultry production as well as in aquaculture. The studies investigating the earthworm meal use are quite old above all those carried out in Europe; however, some general indications can be drawn: both for broiler and fish, the parameters usually evaluated are body weight gain, growth rate, feed intake and feed conversion rate, the acceptability level of earthworm meal in broiler diet is lower than 15% while in trout diet ranges between 25 and 30%. The inclusion of earthworm meal in diets with an inclusion level lower than the acceptability threshold allows good productive performances without affecting the quality of the final food products
The Rhie-Chow stabilized Box Method for the Stokes problem
The Finite Volume method (FVM) is widely adopted in many different
applications because of its built-in conservation properties, its ability to
deal with arbitrary mesh and its computational efficiency. In this work, we
consider the Rhie-Chow stabilized Box Method (RCBM) for the approximation of
the Stokes problem. The Box Method (BM) is a piecewise linear Petrov-Galerkin
formulation on the Voronoi dual mesh of a Delaunay triangulation, whereas the
Rhie-Chow (RC) stabilization is a well known stabilization technique for FVM.
The first part of the paper provides a variational formulation of the RC
stabilization and discusses the validity of crucial properties relevant for the
well-posedeness and convergence of RCBM. Moreover, a numerical exploration of
the convergence properties of the method on 2D and 3D test cases is presented.
The last part of the paper considers the theoretically justification of the
well-posedeness of RCBM and the experimentally observed convergence rates. This
latter justification hinges upon suitable assumptions, whose validity is
numerically explored.Comment: 27 pages, 6 figures, 4 table
Issues Facing Design Professionals through the Lens of Two Rain-Induced Roof Collapses
The drainage of low-sloped roof systems involves multiple design professionals, and often each has a different opinion as to their design responsibility. Roofing issues have been identified as being a number one source of litigation, and rain-induced roof collapses continue to occur with alarming frequency. With the backdrop of several rain-induced roof collapses, this paper illustrates the complexity of assigning design responsibility for drainage systems; and investigates a variety of outcomes associated with the current building code provisions transporting rainwater from large low-sloped roof structures
Sublethal effects induced by morphine to the freshwater biological model Dreissena polymorpha
Opioids are considered as emerging contaminants in aquatic ecosystems, mainly due to their large illicit consume worldwide. Morphine (MOR) is the main opiate and it was commonly found at measurable concentrations in freshwaters. Even though its occurrence is well documented, just limited information is available regarding its hazard to nontarget organisms. The aim of this study was of the evaluation of sublethal effects induced by MOR to the freshwater bivalve Dreissena polymorpha. We exposed mussels to two MOR concentrations (0.05 \ub5g/L and 0.5 \ub5g/L) for 14 days and we investigated the sublethal effects by a suite of biomarkers. The Neutral Red Retention Assay (NRRA) was used as a test of cytotoxicity, while the oxidative stress was evaluated by the activity of antioxidant and detoxifying enzymes, namely catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), and by measuring the levels of lipid peroxidation (LPO) and protein carbonylation (PCC). The genetic damage was assessed by the Single Cell Gel Electrophoresis (SCGE) assay, the DNA diffusion assay and the micronucleus test (MN test). Finally, the filtration rate of D. polymorpha was evaluated in order to investigate possible physiological effects. Both tested concentrations reduced the lysosome membrane stability of bivalves, but only the highest MOR concentration induced significant changes in the activity of antioxidant enzymes (SOD, CAT, and GPx) and increase in lipid peroxidation levels. Slight increase in primary DNA fragmentation was noticed, while no fixed genetic damage and alterations of the filtering rate were found
Direct measurement of DNA-mediated adhesion between lipid bilayers
Multivalent interactions between deformable mesoscopic units are ubiquitous
in biology, where membrane macromolecules mediate the interactions between
neighbouring living cells and between cells and solid substrates. Lately,
analogous artificial materials have been synthesised by functionalising the
outer surface of compliant Brownian units, for example emulsion droplets and
lipid vesicles, with selective linkers, in particular short DNA sequences. This
development extended the range of applicability of DNA as a selective glue,
originally applied to solid nano and colloidal particles. On very deformable
lipid vesicles, the coupling between statistical effects of multivalent
interactions and mechanical deformation of the membranes gives rise to complex
emergent behaviours, as we recently contributed to demonstrate [Parolini et
al., Nature Communications, 2015, 6, 5948]. Several aspects of the complex
phenomenology observed in these systems still lack a quantitative experimental
characterisation and fundamental understanding. Here we focus on the
DNA-mediated multivalent interactions of a single liposome adhering to a flat
supported bilayer. This simplified geometry enables the estimate of the
membrane tension induced by the DNA-mediated adhesive forces acting on the
liposome. Our experimental investigation is completed by morphological
measurements and the characterisation of the DNA-melting transition, probed by
in-situ F\"{o}rster Resonant Energy Transfer spectroscopy. Experimental results
are compared with the predictions of an analytical theory that couples the
deformation of the vesicle to a full description of the statistical mechanics
of mobile linkers. With at most one fitting parameter, our theory is capable of
semi-quantitatively matching experimental data, confirming the quality of the
underlying assumptions.Comment: 16 pages, 7 figure
An explicit dynamics GPU structural solver for thin shell finite elements
With the availability of user oriented software tools, dedicated architectures, such as the parallel computing
platform and programming model CUDA (Compute Unified Device Architecture) released by NVIDIA,
one of the main producers of graphics cards, and of improved, highly performing GPU (Graphics
Processing Unit) boards, GPGPU (General Purpose programming on GPU) is attracting increasing interest
in the engineering community, for the development of analysis tools suitable to be used in validation/
verification and virtual reality applications. For their inherent explicit and decoupled structure, explicit
dynamics finite element formulations appear to be particularly attractive for implementations on hybrid
CPU/GPU or pure GPU architectures. The issue of an optimized, double-precision finite element GPU
implementation of an explicit dynamics finite element solver for elastic shell problems in small strains
and large displacements and rotations, using unstructured meshes, is here addressed. The conceptual
difference between a GPU implementation directly adapted from a standard CPU approach and a new
optimized formulation, specifically conceived for GPUs, is discussed and comparatively assessed. It is
shown that a speedup factor of about 5 can be achieved by an optimized algorithm reformulation and
careful memory management. A speedup of more than 40 is achieved with respect of state-of-the art
commercial codes running on CPU, obtaining real-time simulations in some cases, on commodity hardware.
When a last generation GPU board is used, it is shown that a problem with more than 16 millions
degrees of freedom can be solved in just few hours of computing time, opening the way to virtualization
approaches for real large scale engineering problems
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