30 research outputs found

    Effects of acute and chronic temperature changes on the functional responses of the dogfish Scyliorhinus canicula (Linnaeus, 1758) towards amphipod prey Echinogammarus marinus (Leach, 1815)

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    Predation is a strong driver of population dynamics and community structure and it is essential to reliably quantify and predict predation impacts on prey populations in a changing thermal landscape. Here, we used comparative functional response analyses to assess how predator-prey interactions between dogfish and invertebrate prey change under different warming scenarios. The Functional Response Type, attack rate, handling time and maximum feeding rate estimates were calculated for Scyliorhinus canicula preying upon Echinogammarus marinus under temperatures of 11.3 °C and 16.3 °C, which represent both the potential daily variation and predicted higher summer temperatures within Strangford Lough, N. Ireland. A two x two design of “Predator Acclimated”, “Prey Acclimated”, “Both Acclimated”, and “Both Unacclimated” was implemented to test functional responses to temperature rise. Attack rate was higher at 11.3 °C than at 16.3 °C, but handling time was lower and maximum feeding rates were higher at 16.3 °C. Non-acclimated predators had similar maximum feeding rate towards non-acclimated and acclimated prey, whereas acclimated predators had significantly higher maximum feeding rates towards acclimated prey as compared to non-acclimated prey. Results suggests that the predator attack rate is decreased by increasing temperature but when both predator and prey are acclimated the shorter handling times considerably increase predator impact. The functional response of the fish changed from Type II to Type III with an increase in temperature, except when only the prey were acclimated. This change from population destabilizing Type II to more stabilizing Type III could confer protection to prey at low densities but increase the maximum feeding rate by Scyliorhinus canicula in the future. However, predator movement between different thermal regimes may maintain a Type II response, albeit with a lower maximum feeding rate. This has implications for the way the increasing population Scyliorhinus canicula in the Irish Sea may exploit valuable fisheries stocks in the future

    Immunomodulating activity of RU 41740 : in vitro and in vivo studies on human lymphocytes

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    A group of institutionalized elderly subjects, selected on the basis of their skin hypoergy and displaying different kinds of T and B lymphocyte impairments has been chosen as a model to verify the in vivo immunopotentiating activity of RU 41740 on human lymphocytes. Oral treatment with the drug was able to: (a) restore or improve the cutaneous delayed hypersensitivity to recall antigens; (b) significantly increase the blastigenetic response to mitogenic and submitogenic doses of PHA and PWM and (c) improve the in vitro PWM-induced synthesis of IgG and IgM. The immunooharmacological activity of RU 41740 appeared to persist three months after the end of therapy, without any direct stimulating activity on the peripheral blood lymphocytes. The in vitro results seem to suggest that peripheral lymphocytes are not directly influenced by the drug

    Immunoprophylaxis in "septic risk" patients undergoing surgery for gastrointestinal cancer. Results of a randomized, multicenter clinical trial.

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    Abstract The results of a randomized, multicenter clinical trial of immunoprophylaxis of post-operative infections with intravenous Immunoglobulins (IVIG) (Sandoglobulin) in "septic-risk" patients undergoing surgery for gastrointestinal cancer are presented. "Septic-risk" patients were selected by an original multiparametric test based on delayed hypersensitivity skin testing and serum protein electrophoretic sub-fractions. This screening test had shown 76% positive predictivity in a previous validation assessment. In the present study, 159 "septic-risk" patients were selected prospectively from 369 patients undergoing colo-rectal (colon) and other kinds of gastrointestinal (non-colon) oncologic surgery: 80 "septic-risk" patients were included in the colon and 79 in the non-colon group. Immunoprophylaxis with IVIG (15 g on the day prior to operation, on the 1st and 5th postoperative days) was randomly associated with antibiotic prophylaxis (cefoxitin: 2 g one hour prior to, followed by 2 g at the end of operation plus 2 g every six hours for 24 hours) in colon surgery while the prophylactic schedule in non-colon surgery was only based on random administration of IVIG, at the same dosage as in the colon group. There was a clear-cut reduction of post-operative infections both in colon and non-colon "septic-risk" patients who had IVIG prophylaxis; in the colon group, 37 and 21 infections (P < 0.004) in antibiotic (A) versus IVIG plus antibiotic (IVIG + A) subset, respectively; in the non-colon group, 33 and 19 infections (P < 0.01) in control (C) versus (IVIG) subset, respectively.(ABSTRACT TRUNCATED AT 250 WORDS

    Morphing electroadhesive interface to manipulate uncooperative objects

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    The possibility of handling uncooperative objects, i.e. objects not equipped with any features that can aid their manipulation, is of particular interest for both terrestrial and space robotic applications. In this framework, this paper deals with the development and testing of a smart material substrate, which can be integrated into an end-effector device, where morphing and electro-adhesive capabilities are combined to allow the manipulation of uncooperative objects of different shapes and materials. Compliance and adhesion properties are obtained by creating a conductive pattern of electrodes embodied on the surface of a polymeric substrate. On one hand, the polymeric material, activated by a change in temperature, can adapt to any shape when it is heated, and maintain the deformed shape after being cooled, even when the load is removed, becoming compliant with the objects surface. On the other hand, the conductive pattern is responsible for the adhesive effect: when a high voltage is applied, the electric field generated induces an opposite charge on the objects surface establishing reversible attraction forces. Furthermore, the conductive pattern could be used to activate the morphing behaviour when the manipulator and the target object come into contact. A resistive-electroadhesive pad is realized and some tests are performed to verify the heating behavior of the electrodes and the electroadhesion forces achievable. Morphing tests are also performed to verify the ability of the polymeric substrate to maintain the deformed shape after coolin
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