9,346 research outputs found
Recupero e consolidamento della collezione scheletrica del Museo di Zoologia “Doderlein”
Il presente articolo illustra un’operazione di restauro che ha aperto una fase di recupero di diversi elementi scheletrici, da tempo deteriorati, nel Museo di Zoologia “Doderlein”, oggi afferente al Sistema Museale d’Ateneo - SIMUA - dell’Università degli Studi di Palermo. Il lavoro si è articolato in pulitura, restauro e consolidamento di cinquanta pezzi dei cinque gruppi di vertebrati. Questo intervento rappresenta solamente una piccola tessera di un progetto più ampio, che ha come obiettivo finale il recupero dell’intera collezione zoologica presente in Museo.The present work took place in the Museum of Zoology “Doderlein” of the SIMUA, University of Palermo. A restoration of skeletons was performed following the main phases: cleaning, restoration and consolidation of fifty pieces of the main five vertebrate taxa. This action represents the beginning of a wider project, of which the final aim is to recover the entire zoological collection present in the Museum
Sensitivity of hypogean and epigean freshwater copepods (Crustacea Copepoda) to agricultural pollutants: single toxicants and mixtures
Widespread pollution from agriculture is one of the major causes of poor freshwater quality currently observed across Europeand worldwide. Nutrient loads (nitrogen and phosphorous) from fertilizers and pesticides are known to adversely impact freshwater ecosystems, both surface- and ground water. The Crustacea Copepoda are by far the most abundant and species-rich taxon in ground water and they are consistently represented in ecotonal environments also, as in the hyporheic zone. The direct impact of agricultural pollutants on freshwater biota has been addressed in several studies by means of laboratory bioassays. However, the ecotoxicological research concerning freshwater copepods is scarce for epigean species and almost non-existent for the hypogean ones. Moreover, when available, ecotoxicological studies have been performed considering the effect of toxicants taken individually. Actually, this approach does not reflect the conditions in the field high concentrations of both N-fertilizers and pesticides co-occur. In this study we assessed the acute (at 96h) sensitivity of adults of a hypogean and an epigean species, both belonging to the Crustacea, Copepoda, Cyclopoida, Cyclopidae, to two agricultural toxicants: the ammonium nitrate and the herbicides Imazamox. Both chemicals are widely used for cereal agriculture inEurope. We tested the sensitivity considering the LC50 with mortality endpoints for individual and combined (a mixture solution of ammonium nitrate and Imazamox) toxicant concentrations. The hypogean species was more sensitive than the epigean one to both chemicals and their mixture. Ionized ammonia proved to be more toxic than the herbicide Imazamox for both species. However, the LC50 of both chemicals were lower than the actual standard law limits for good freshwater quality status defined by the Water Framework Directive (2000/60/CE). The effect of the mixture, of the two toxicants was fairly synergic. Concerning ionized ammonia, the LC50-96h in the mixture was higher than the law limits for both species. According to these results, the actual law limits for the good quality of freshwater bodies should be revised accordingly by authorities in charge of water management
Simplified primary energy models for the selection of Electron Beam Melting over turning in the production of titanium alloys components
Over the last years two factors have deeply affected research in Manufacturing: the growing interest around Additive Manufacturing (AM) processes and the need to reduce the anthropogenic environmental impact. As result, a large papers concerning the environmental impact performance of AM compared to conventional processes have been published. Specifically, very complex models accounting for the impact of each life cycle stage of AMed components have been released. Results revealed that AM, at present, guarantees energy savings only within some domains, and the potential saving depends on several factors: product complexity, eco-properties of the material, energy intensity of the material deposition, light-weighting enabled by AM approaches and extent of the use phase. Above all, the result of the comparative analysis depends both on the considered factors and on the selected system boundaries. The already proposed models are very complex and many inventory data are needed, this could make them unapplicable at industrial level. In the presented paper, simplified models are proposed and the performances of these are quantified with varying the analyzed scenario (considered factors and selected system boundary). Results revealed that, for given scenarios, simplified models characterized by low computational effort, can provide reliable results. Guidelines for the implementation of different models with varying the system boundary are provided for the cumulative energy comparison of Electron Beam Melting and conventional turning for the production of titanium alloys components
Distributed Sum-Rate Maximization of Cellular Communications with Multiple Reconfigurable Intelligent Surfaces
The technology of Reconfigurable Intelligent Surfaces (RISs) has lately
attracted considerable interest from both academia and industry as a low-cost
solution for coverage extension and signal propagation control. In this paper,
we study the downlink of a multi-cell wideband communication system comprising
single-antenna Base Stations (BSs) and their associated single-antenna users,
as well as multiple passive RISs. We assume that each BS controls a separate
RIS and performs Orthogonal Frequency Division Multiplexing (OFDM)
transmissions. Differently from various previous works where the RIS unit
elements are considered as frequency-flat phase shifters, we model them as
Lorentzian resonators and present a joint design of the BSs' power allocation,
as well as the phase profiles of the multiple RISs, targeting the sum-rate
maximization of the multi-cell system. We formulate a challenging distributed
nonconvex optimization problem, which is solved via successive concave
approximation. The distributed implementation of the proposed design is
discussed, and the presented simulation results showcase the interplay of the
various system parameters on the sum rate, verifying the performance boosting
role of RISs.Comment: 5 pages, 1 figure. Presented in IEEE SPAWC 202
Cereal Lignans, Natural Compounds of Interest for Human Health?
Cereals are suggested to be the most important sources of lignan in the diets of western populations. Recent epidemiological studies show that European subpopulations in which the major source of lignans are cereals, display lower disease frequency regarding metabolic and cardiovascular diseases. The biological mechanisms of lignan are several. Beyond their antioxidant and anti-inflammatory actions at nutritional doses some lignans regulate the activity of specific nuclear receptors (NRs), such as the estrogen receptors (ERs), and also NRs that are central switches in glucose and fatty acid metabolism such as PPAR alpha, PPAR gamma and LXRs, highlighting them as selective nuclear receptor modulators (SNRMs). These include enterodiol (END) and enterolactone (ENL), the metabolites produced by the gut microbiota from food lignans. The available knowledge suggests that given some additional research it should be possible to make 'function' claims for a regular intake of lignans-rich foods related to maintaining a healthy metabolism
Oilseeds ameliorate metabolic parameters in male mice, while contained lignans inhibit 3T3- L 1 adipocyte differentiation in vitro
Purpose and background The focus was directed to the
study of two of the most lignan-rich food sources: sesame
and flaxseeds. Recent epidemiological and experimental
evidences suggesting that these foods may improve metabolic functions underlying metabolic syndrome (MetS).
Methods To characterize the effect of these oilseeds on
metabolic functions, we conducted an experimental study
aimed at preventing adiposity and metabolic imbalance in a
mouse model of high-fat diet (HFD)-induced MetS. Statistical analysis was performed by two-way analysis of
variance test followed by post hoc Bonferroni analysis.
Results We studied the effect of the oilseeds sesame and
flaxseed on metabolic parameters in mice on a HFD. When
the HFD was integrated with 20 % of sesame or flaxseed
flours, the mice showed a decrease in body fat, already at
day 15, from time 0. The size of the adipocytes was smaller
in epididymal fat, liver steatosis was inhibited, and insulin
sensitivity was higher in mice on the supplemented diets.
The supplemented diets also resulted in a significant
increase in the serum levels of the lignan metabolites enterodiol and enterolactone compared with the controls. The expression of genes associated with the inflammatory
response, glucose metabolism, adipose metabolism and
nuclear receptor were altered by the oilseed-supplemented
diets. Some of the most abundant lignans in these oilseeds
were studied in 3T3-L1 preadipocyte cells and were
effective in inhibiting adipocyte differentiation at the
minimal dose of 1 nM.
Conclusions The consumption of sesame and flaxseed
may be beneficial to decrease metabolic parameters that are generally altered in MetS
I resti scheletrici della grotta di S. Teodoro presso il Museo Gemmellaro di Palermo: il nuovo restauro conservativo di ST2
The work describes the restoration of the cranium ST2 of the Epipalaeolithic site of S. Teodoro, Sicily. This restoration has been conducted in accordance to modern criteria of conservation limiting the integrative and reconstructive interpretation to the minimum. After the restauration ST2 has been morphologically described and measured. The fortuitous recovery of a left incus bone allowed
its morphological and metrical description
An energy efficiency analysis of single point incremental forming as an approach for sheet metal based component reuse
Producing materials causes about 25% of all anthropogenic CO2 emissions. Metals play a significant role, steel and aluminum account for 24% and 3% of worldwide material related emissions respectively. Fostering resources efficiency strategies in the field of sheet components could lead to a significant environmental impact reduction. Reshaping could be one of the most efficient strategy to foster material reuse and lower the environmental impact due to material production. Specifically, for aluminum recycling, the overall energy efficiency of conventional route is very low and, more importantly, permanent material losses occur during re-melting because of oxidation. The present paper aims at presenting the technical feasibility of Single Point Incremental Forming (SPIF)-based reshaping approach. Change in shape of aluminum stamped part is obtained through SPIF process implementation. Preliminary energy savings quantification through life cycle energy and material flows modelling are provided, energy efficiency of conventional recycling approach and SPIF-based reshaping routes are analyzed and compared
A chronic strain of the cystic fibrosis pathogen Pandoraeapulmonicola expresses a heterogenous hypo-acylated lipid A
Pandoraeasp. is an emerging Gram-negative pathogen in cystic fibrosis causing severe and persistent inflammation and damageof the lungs. The molecular mechanisms underlying the high pathogenicity ofPandoraeaspecies are still largely unknown. AsGram-negatives,Pandoraeasp. express lipopolysaccharides (LPS) whose recognition by the host immune system triggers aninflammatory response aimed at the bacterial eradication from the infected tissues. The degree of the inflammatory responsestrongly relies on the fine structure of the LPS and, in particular, of its glycolipid moiety, i.e. the lipid A. Here we report thestructure of the lipid A isolated from the LPS of a chronic strain ofP. pulmonicola(RL 8228), one of the most virulent identifiedso far among thePandoraeaspecies. Our data demonstrated that the examined chronic strain produces a smooth-type LPS with acomplex mixture of hypoacylated lipid A species displaying, among other uncommon characteristics, the 2-hydroxylation ofsome of the acyl chains and the substitution by an additional glucosamine on one or both the phosphate groups
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