7,289 research outputs found
Influence of different iron availability on phosphoenolpiruvate carboxilase and malate dehydrogenase in roots of maize (Zea Mays L.) plants grown under iron deficiency
The effect of the different nitrate availability on some enzymatic activities has been evaluated in iron deficient and iron sufficient maize plants (Zea mays L.). In order to evaluate if the induction of sensitive to pH enzymatic activities is affected by the variation of the apoplast reaction due to the different nitrate availability, two experimental tests were done on maize plants grown in nutrient solution with different NO3- availability and with Fe-sufficiency (+Fe) (added with 80 uM Fe(III)-EDTA) and Fe-deficiency (-Fe) (added with 0.1 uM Fe(III)-EDTA).
As regards 0.4 mM NO3- (NS2), independently of iron availability, phosphoenolpiruvate carboxilase and malate dehydrogenase inductions are higher than those recorded for the experiment with 4.0 mM NO3-. The two activities, for the reaction determined in citosol by NO3- uptake, show different responses according to Fe availability. In NS1 the higher nitrate uptake and the contemporaneous H+ incoming cause in (+Fe) plants a decrease of PEP-carboxilase activation and, during the first 24 hours, of malate dehydrogenase. The shifting of the peak of maximum activity shows that iron deficiency conditions, interfering with e- transport, determinate a slowing down of the enzyme induction, independently of nitrate availability. In NS2, PEPcase is higher under Fe-deficiency and malate dehydrogenase is higher under Fe-sufficiency, both during the first 24 hours.
The different nitrate availability causes a different use of the acid content. In fact, in NS1 citric content, precursor of molecules for the production of phytosiderophores, increased in (-Fe) theses. On the contrary, low nitrate availabilities determined a decrease in acid contents, mostly in (-Fe) theses. This result justifies the higher energy demand to activate membrane carriers under stress conditions for the reduced nitrate availability.

Ouabain-induced cytoplasmic vesicles and their role in cell volume maintenance
Cellular swelling is controlled by an active mechanism of cell volume regulation driven by a Na+/K+-dependent ATPase and by
aquaporins which translocate water along the osmotic gradient. Na+/K+-pump may be blocked by ouabain, a digitalic derivative,
by inhibition of ATP, or by drastic ion alterations of extracellular fluid. However, it has been observed that some tissues are still able
to control their volume despite the presence of ouabain, suggesting the existence of other mechanisms of cell volume control. In
1977, by correlating electron microscopy observation with ion and water composition of liver slices incubated in differentmetabolic
conditions in the presence or absence of ouabain, we observed that hepatocytes were able to control their volume extruding water
and recovering ion composition in the presence of ouabain. In particular, hepatocytes were able to sequester ions and water in
intracellular vesicles and then secrete themat the bile canaliculus pole.We named this âvesicularmechanismof cell volume control.â
Afterward, thismechanism has been confirmed by us and other laboratories in several mammalian tissues.This review summarizes
evidences regarding this mechanism, problems that are still pending, and questions that need to be answered. Finally, we shortly
review the importance of cell volume control in some human pathological conditions
Il posto del mondo nellâuomo: la mundana sapientia di Kant
In spite of current interpretations, this essay investigates the intimate link between cosmology and anthropology in Kantâs thought. Drawing the most incisive consequences both of the copernican revolution and Colomboâs discovery, Kantâs cosmological anthropology reveals to be the modern uneasy mundana sapientia, and let us thoroughly understand the pregnant meaning of the historiographic topos âman and worldâ. World â not God, Being or Truth, and even not Reality â assert itself as the most important reference point to comprehend human condition, although the world-concept became far more problematic than in the past In cosmological perspective world is neither exclusively nature nor exclusively ideal guidance, but pragmatic-cosmopolitan world, i.e. a pervasive âin-between positionâ, which causes a constitutive imbalance we have permanent to cop with. So is open the way leading to contemporary philosophical anthropology
Quantitative risk assessment on a hydrogen refuelling station
The Directive 2014/94/UE (DAFI, Alternative Fuel Initiative Directive) on the deployment of alternative fuels (i.e. hydrogen) infrastructures has been recently transposed into national law in Italy. Consequently, the technical regulation on fire prevention for H2fuelling stations has been updated, in order to consider the current maximum delivery pressure (700 bar) of gaseous hydrogen for road vehicles. This technical regulation establishes the prescriptive safety distance from a piece of equipment. In the case of a new station, an assessment of the frequency of the event and its potential consequences is necessary. This is to understand which risk can reasonably be mitigated by a safety distance or whether additional mitigation or prevention measures should be taken. This paper presents the quantitative risk assessment (QRA) study on a hydrogen station planned to be installed, study which aims at determining the safety distances. Such study utilizes the Sandia-developed QRA tool, Hydrogen Risk Analysis Model (HyRAM), to calculate risk values when developing risk-equivalent plans. HyRAM combines reduced order deterministic models that characterize hydrogen release and flame behavior with probabilistic risk models to quantify risk values. Thanks to HyRAM tool it is possible to estimate physical effects and consequences on people and structures and plants, related to risk scenarios, by means of a damage model library. Use of risk assessment may allow station owners and designers to flexibly define station-specific mitigations, with the purpose of achieving equal or better levels of safety with respect to prescriptive recommendation levels, as suggested by ISO19880-1 (2018)
Interaction ammonium-nitrate: Response to oxidative stress in chicory plants
The aim of this work was to study, as a function of the different availability of nitrogen in the reduced form, mineral and organic, the induction of the synthesis of some ROS-scavenging molecules and the evolution of some enzymatic activities such as ascorbate peroxidase (APX) and polyphenoloxidase (PPO). 
Chicory seedlings were grown in nutritive solution for 35 days in controlled conditions. On the 14th day, one third of the plants was transferred into a nutritive solution containing (NH4)2SO4 60 mM, one third was transferred into a medium containing Urea 60 mM, and the remaining was let grow into the nutrition solution, as a control. Three samplings of leaves were performed, respectively after 21, 28 and 35 days of growth.
The urea and ammonium sulphate-treated samples showed higher ascorbic acid and polyphenol contents than the control, together with a lower anthocyanins content. APX showed the highest activity in the urea-treated samples, while the highest PPO activity was to refer to samples treated with ammonium sulphate.
The variations of the organic components showed the incidence of the nitrogen supply in the reduced form on the cell redox potential, confirming the importance of fertilization for obtaining high amounts of antioxidant molecules.

Progettazione di un impianto per il collaudo di pompe azionate a vapore
Analisi delle varie problematiche relative al collaudo di pompe azionate a vapore alla luce delle normative di riferimento e successiva progettazione dei componenti principali facenti parte dell'impianto
Anticipating the Identification of Contradictions in Eco-design Problemsâ
Eco-improvement tools aim at identifying the most critical areas of a product life cycle, thanks to eco-assessment techniques like LCA. The designer is then encouraged to intervene by modifying the product or the manufacturing process characteristics. However, even a slight change of the product life cycle can seriously affect other parts of the cycle itself. Usually, this influences are hard to predict. Only an expert of LCA could effectively anticipate the major repercussions of a life cycle alteration. However, with the introduction of abridged aLCA, life cycle analysis has become a tool for the common designer, which usually doesn't have the expertise to identify the great number of interdependences involved. In these cases, the designer's efforts in reducing product environmental impacts can be ineffective or even counterproductive. This paper proposes a method and tool, called contradiction prompter, which integrates TRIZ in Life Cycle Assessment. Once environmental criticalities are defined by LCA, a set of guidelines are suggested to intervene on the product. The contradiction prompter collects a set of predefined typical contradictions that can arise when adopting a specific guideline. This can limit the typical trial and error approach and reduce the risk of ineffective redesigns. The framework has been clarified through an exemplary case study, dealing with the redesign of a moped wheel
Analysis of a wearable robotic system for ankle rehabilitation
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. As one of the most commonly injured joints of the human body, the ankle is often subject to sprains or fractures that require motion assistance to recover mobility. Whereas physiotherapists usually perform rehabilitation in one-on-one sessions with patients, several successful robotic rehabilitation solutions have been proposed in the last years. However, their design is usually bulky and requires the patient to sit or stand in a static position. A lightweight wearable device for ankle motion assistance, the CABLEankle, is here proposed for motion ankle exercising in rehabilitation and training. The CABLEankle is based on a cable-driven S-4SPS parallel architecture, which enables motion assistance over the large motion range of the human ankle in a walking gait. The proposed mechanism design is analyzed with kinematic and static models, and the force closure workspace of the mechanism is discussed with analytical results. Finally, the feasibility of the proposed design is investigated through numerical simulations over the ankle motion range as a characterization of the peculiar motion
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