1,229 research outputs found
Rare earths, zirconium and hafnium distribution in coastal areas: The example of Sabella spallanzanii (Gmelin, 1791)
The Zr, Hf, Y and lanthanide (REE) distribution in biological tissues of Sabella spallanzanii and Styela plicata species collected from two harbours from the northern Sicily is studied for providing information regarding the Zr, Hf and REE uptake from the environment. Previous studies determined the fractionation of dissolved REE scavenged on binding sites onto biological surfaces. By comparing the recognised shale-normalised REE patterns of studied samples with evidence from reference data, the observed behaviour of these elements in biological tissues of Sabella spallanzanii and Styela plicata is interpreted to result from the preferential uptake of intermediate REE onto carboxylic sites. Moreover, the relationship observed between the Fe content and Zr/Hf ratio suggests that preferential Hf accumulation occurs via siderophore-like binding sites. Features of the REE bioaccumulation factors (BAF), in addition to the absolute La, Ce and Sm contents and Zr-Hf fractionation, allow definition of the different origins of studied elements in the investigated localities. Higher BAF values for La and Ce associated with larger REE contents and lower Zr/Hf values strongly suggest that the environmental REE distribution in the Termini Imerese harbour is influenced by the delivery of particles from industrial sources and power plants. On the contrary, the REE contents of biological tissues collected in the Cala tourist harbour are affected by the dust dissolution from automotive traffic. These results suggest that the geochemical behaviour of REE and Zr/Hf signature can be used in environmental studies of biological tissues for reconstructing the nature of anthropogenic contaminations
DIVERSITY OF LECTIN-SUGAR RECOGNITION SYSTEMS IN THE EVOLUTION OF FISH INNATE IMMUNITY
Carbohydrate recognition and interactions mediated by lectins have been recognized involved in vertebrate innate immunity, not only for recognition of potential pathogens, but also acting in the agglutination, immobilization and other functional steps.
Fish are equipped with a complex lectin repertoire that, like mammals, are involved almost all the immune reactions.
On the basis of our results on the isolation, cDNA cloning, structural analysis, tissue expression and localization, and opsonic activity of F-type and RBL lectins from Dicentrarchus labrax and Sparus aurata we showed that:
lectin repertoires in fish are highly diversified and include not only representatives of the lectin families; described in mammals, but also members of lectin families described for the first time in fish species like the F type lectins;
the tissue-specific expression and localization of the diverse lectin repertoires and their molecular partners is consistent with their distinct biological roles in innate and adaptive immunity;
although some lectins may bind endogenous ligands, others bind sugars on the surface of potential pathogens; in addition to pathogen recognition and opsonization, some lectins display additional effector roles, such as regulation of immune function
Risposta sismica di edifici prefabbricati isolati con dispositivi elastomerici
The paper concerns the seismic behavior of precast concrete industrial buildings with an elevation equipped with seismic isolators. It’s examined a building with rectangular plan of m 40x 50. The structure is constituted of columns of square cross-section of 0.6 m, with continuum beams foundation. The desk is made with T section beams for each frame connected by Gerber joints in the main direction and they support precast pre-tensioned tiles with shape. A plate of concrete is casted of the wing tiles for obtain a connected rigid deck.
At the top of the pillars will be placed rubber bearings having high dissipation capacity (HDRB).
The dynamic behavior of the structure under recorded real strong accelerograms is examined. In this work are considered Friuli, Loma Prieta, Northridge and Kobe accelerograms, dynamic incremental analysis are conducted in order to obtain the response of structure.
The concrete behavior is assumed with Mander law for the pillars, while the beams have a linear elastic behavior.
For the isolators a linearized constitutive law, using equivalent stiffness, is assumed.
The design criteria of isolated precast systems are highlight, in detail the use of isolators permit to reduce the dimensions and the reinforcing bars amount of pillars. It is need to connect the precast beams of the deck for obtain a rigid deck motion
Multiple Wesen
Abstract in tedesco del Poster Multiple Wesen, esposto al Simposio internazionale „Lunar Base. Bauen fuer ein Leben auf dem Mond” tenuto a Kaiserslautern il 12-13 Maggio 2009.
Was baut man auf dem Mond? Wie baut der Erdmensch auf dem Mond? Wofür wird gebaut? Für wem wird gebaut? Welche Nutzungen, wie groß, welche Materialien? Man kann weiter fragen,... Sind dieses überhaupt die richtige Fragen? Kann man überhaupt vom Bauen auf dem Mond sprechen? Oder geht es darum, was der Mensch auf den Mond mit bringt, aus seiner Kenntniss, seinen Vorstellungen, seinen Träumen, seiner Erfahrung: was bringt er von dem Reich des Bekannten (der Erde) in das Reich des nur Vorstellbaren (dem Mond). Also: sich mit dem Mond zu beschäftigen - ausgenommen für die sehr wenigen, die schon dort waren – heißt, sich mit sich selbst zu beschäftigen, mit dem eigenen Wissen und dem Bild vom Mond. Alle Voraussetzungen, die einem irdischen architektonischen Entwurf zu Grunde liegen, fehlen; zu diesem Zeitpunkt kann man sich arbiträr Rahmenbedingungen geben: (Größe, wo, welche Nutzung, welche Lebensdauer, welche Materialien) so zu sagen ein Mondprojekt in einem Erdprojekt zu entwickeln, dadurch schnell eine „abgesicherte“, unangreifbare Lösung zu erlangen. Aber macht dieses Sinn? Bedeutet dies, die Spannung und die Erforschung des Neuen sowie das kreative Potential örtlicher Schwierigkeiten im Vorfeld auszuschließen? Wir schlagen vor, anstatt auf hiesige Fragen irdische Antworten zu formulieren, Strukturen zum Mond zu bringen; Raumstrukturen, die durch mentale Konzepte begründet sind, welche die vielen Fragen - auch welche die wir jetzt nicht zu fragen gewagt haben - aufnehmen können. Diese Strukturen, aber auch kleine räumliche Gebilde, helfen dem Vorstellungsvermögen der Forscher, Ingenieure, Wissenschaftler und alle Mondinteressenten. Neutrale Strukturen, ohne jetzt genau alle physische Eigenschaften festlegen zu wollen, sollen Raum werden können für Wohnen, Arbeiten, Forschen, Landen, Binden, Schützen, Aufbewahren, usw. - abhängig von den Fragen, die sich zu gegebener Zeit formulieren lassen und ständig ändern werden. Wir denken an sehr flexible Strukturen, die viel aufnehmen und aushalten können, sich sehr schnell transformieren lassen, also multiple Wesen, die zunächst die Vorstellung eines belebten Mondes anregen sollen. Dieser Strukturenkatalog soll dem Wissenschaftler zur Verfügung stehen, um das Mitdenken seiner räumlichen Bedürfnisse zu stützen.
Comunicato stampa
Contributo degli studenti di Architettura al Simposio “Lunar Base - Costruire per una vita sulla
Luna”
A Kaiserslautern in Germania è in corso (12-13-maggio) il Simposio “Lunarbase - Bauen fuer ein
Leben auf dem Mond” (www.lunar-base.net) organizzato dalla DLR (Agenzia aerospaziale tedesca)
e dalla TU Kaiserslautern. Scienziati, ingegneri, architetti e designer di tutto il mondo presentano i
loro piani e le loro visioni per una possibile vita sulla Luna. Alcune nazioni tra le quali la Cina, la
Russia e gli Stati Uniti stanno elaborando piani concreti per la costruzione di stazioni lunari come
basi per missioni equipaggiate su Marte, con un orizzonte temporale intorno al 2020. La proposta
degli studenti dei Laboratori di I anno di Progettazione architettonica, tenuti dal Prof. Gaetano
Licata con la collaborazione del dottorando in Design Michele Cammarata nel nuovo corso di
Laurea triennale in Scienze dell’Architettura (SdA) e nel Corso di Laurea quinquennale (4/s), è stata
selezionata dal comitato organizzatore che ne ha richiesto l’elaborazione sotto forma di un Poster
(A0) attualmente esposto durante il Simposio. Si tratta di un montaggio di modelli tridimensionali
elaborati dagli studenti e denominati “multiple Wesen”. Questi modelli, in quanto concetti di
architettura assolutamente astratti, si prestano a contribuire a quel bagaglio di conoscenze, visioni,
sogni e immaginazione, che chiunque voglia “confrontarsi” con una realtà solo immaginabile come
quella della Luna, ha bisogno di “portare con sé” dalla Terra. Concetti mentali di spazi possibili –
“Raumstrukturen” - a sostegno degli scienziati, per poter continuare a immaginare insieme sempre
piĂą concretamene la vita e la ricerca direttamente sulla Luna.
Pa, 13.05.2009 ([email protected]
COMPORTAMENTO DI IMPALCATI DA PONTE A CASSONE IN ACCIAIO-CALCESTRUZZO CON ANIMA ONDULATA
La memoria riguarda il comportamento di un impalcato di ponte stradale a cassone avente le anime sagomate secondo una sinusoide, con soletta in c.a. collaborante. L'impalcato presenta schema statico longitudinale di trave continua su 4 appoggi.The paper concerns the behaviour of a box-girder bridge deck road having a steel box and a concrete slab. The steel webs are shaped according to a sine wave. The deck has a width of 13.70 m and a length of 182 m, with the longitudinal static scheme as a continuous beam on four supports. The study highlights the reliability of this constructive solution
Seasonal changes in morpho-functional aspects of two Anemonia sulcata (Pennant, 1777) wild populations
Marine benthic organisms can be used as indicators of the quality of environmental status and as monitoring tools to detect natural or anthropogenic perturbations. In temperate waters, metabolic and biochemical responses may be governed by physiological changes driven by seasonal factors. Gathering baseline information on the mechanisms underlying seasonal acclimation patterns is therefore a critical step towards the understanding of the physiological responses of biological indicators. In poikilothermic metazoans, the production of regulatory metabolic enzymes can be used as tools for deciphering the acclimation potential. The aim of this study was to characterize the natural seasonal variability in biometric traits and enzymatic biomarkers over a 12-month period in the sea anemone, Anemonia sulcata (Anthozoa, Cnidaria), from two areas with different environmental and anthropic impacts. Seasonality and site factors affected enzymatic kinetics at tentacle levels, while seasonality, site and biometrical characteristics modulated the same enzymes in the body column of A. sulcata. The results showed a decrease in enzymatic activity in summer and an increased synthesis of enzymes in the late fall and winter months. The interaction between biometric features and temperature appeared significant for mesolittoral sea anemones but not for infralittoral specimens. This study showed seasonal patterns of variations of biochemical responses in A. sulcata, suggesting that this species, an abundant member of shallow rocky bottom communities in temperate European seas, may represent a sensitive bio-indicator organism worth considering for further ecological studies on climate change as well as for environmental monitoring programs
Evidence of cytotoxic activity against mammalian red blood cell of Na+ channel neurotoxin (AE1) from sea anemone (actinia equina)
The diversification of anthozoan toxins played an important role in the ability to colonize various ecological niches. In this study we evaluated the hemolytic activity of HPLC separated fraction of tentacle extracts of sea anemone Actinia equina. Toxic components from acid tissue tentacle extracts were investigated by size exclusion and reverse phase HPLC to characterize cytolytic molecules. A novel low molecular weight active fraction was sequenced by MALDI TOF analysis and a protein correspondent to 5.4 kDa Sodium channel neurotoxin (Ae1) from A. equina was identified. Synthetic Ae1 was assayed and it showed an hemolytic activity against mammalian erythrocytes in a dose dependent manner. Cytolytic activity in addition to neuro-inhibitory function could be a further property of Ae1 toxin repertoire
Unveiling the timescale of the R-T transition in human hemoglobin
Time-resolved wide-angle X-ray scattering, a recently developed technique allowing to probe global structural changes of proteins in solution, was used to investigate the kinetics of R–T quaternary transition in human hemoglobin and to systematically compare it to that obtained with time-resolved optical spectroscopy under nearly identical experimental conditions. Our data reveal that the main structural rearrangement associated with the R–T transition takes place 2 μs after the photolysis of hemoglobin at room temperature and neutral pH. This finding suggests that the 20 μs step observed with time-resolved optical spectroscopy corresponds to a small and localized structural change
Seabream (Sparus aurata) long-term dominant-subordinate interplay affects phagocytosis by peritoneal cavity cells
Fish are sensitive to stressful conditions that affect their innate immune systems and increase their susceptibility to diseases. We examined the social stress of paired gilthead seabream (Sparus aurata). Social hierarchies (dominant/subordinate) were characterised by behavioural changes, such as \u201caggressiveness\u201d and \u201cfeeding order\u201d; hierarchical positions were established within an hour of exposure to social stress and remained unchanged for approximately 1 year.
To characterise physiological stress, we measured blood plasma levels of cortisol, glucose, and lactate as well as osmolarity and observed that the levels of these stress markers were higher in subordinate individuals than in dominant ones. The discriminant analysis revealed a separation of the subordinate fish groups, and at 15 days, a significant separation among groups was observed.
Moreover, diminished phagocytic and respiratory burst activities revealed that social stress appeared to affect the cellular innate immune response of the subordinate specimens.
Finally, to examine the effect of cortisol on phagocytosis, peritoneal cavity cells were treated in vitro, and an inhibitory effect was observed
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