88 research outputs found

    Integration of robotic systems in a packaging machine: A tool for design and simulation of efficient motion trajectories

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    In this paper, the advantages of CACSD (Computer Aided Control System Design) tools for integrating a robotic system in a packaging machine are illustrated. Beside the mechanical integration of the robot into the machine architecture, it is necessary a functional integration, that requires a precise synchronization with the other parts of the system. In the proposed application, a robot with a parallel kinematics is used for pick-and-place tasks between two conveyor belts. It is therefore necessary a proper motion planning which allows to synchronize the grasp and release phases with the conveyor belts, avoiding obstacles and guaranteeing the compliance with bounds on velocity, acceleration and limits in the workspace. A trajectory composed by quintic polynomials has been considered and a specific tool has been designed in the Matlab environment, which allows to modify the parameters of the trajectory and to analyze the obtained motion profiles from both the kinematic and dynamic point of view

    Gold nanoparticles supported on functionalized silica as catalysts for alkyne hydroamination: A chemico-physical insight

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    Highly stable gold nanoparticles anchored on propynylcarbamate-functionalized silica (Au/SiO2@Yne) have been efficiently utilized for the heterogeneous hydroamination of phenylacetylene with aniline under different reaction conditions. In order to ascertain the eventual influence of surface silanol groups on the system activity and selectivity tailored modifications of Au/SiO2@Yne catalysts were pursued according to two different strategies, involving respectively functionalization with trimethylethoxysilane (Au/SiO2@Yne-TMS) or post-treatment with triethylamine (Au/SiO2@Yne-NEt3). The prepared materials were analysed by several complementary techniques such as Solid State NMR (SS NMR), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD). A comparison of the resulting catalytic activities with that of the pristine Au/SiO2@Yne revealed a significant improvement for Au/SiO2@Yne-NEt3 in terms of both conversion and selectivity. Recycling and stability studies showed a catalytic activity decrease after the first run, due to the formation of polyphenylacetylene (PPhA) oligomers shielding the active sites. PPhA removal by sonication in acetone fully restored the catalytic activity and empowered the system with a good operational stability, a very crucial issue in view of eventual practical applications

    Cytochalasin B Influences Cytoskeletal Organization and Osteogenic Potential of Human Wharton’s Jelly Mesenchymal Stem Cells

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    Among perinatal stem cells of the umbilical cord, human Wharton’s jelly mesenchymal stem cells (hWJ-MSCs) are of great interest for cell-based therapy approaches in regenerative medicine, showing some advantages over other MSCs. In fact, hWJ-MSCs, placed between embryonic and adult MSCs, are not tumorigenic and are harvested with few ethical concerns. Furthermore, these cells can be easily cultured in vitro, maintaining both stem properties and a high proliferative rate for several passages, as well as trilineage capacity of differentiation. Recently, it has been demonstrated that cytoskeletal organization influences stem cell biology. Among molecules able to modulate its dynamics, Cytochalasin B (CB), a cyto-permeable mycotoxin, influences actin microfilament polymerization, thus affecting several cell properties, such as the ability of MSCs to differentiate towards a specific commitment. Here, we investigated for the first time the effects of a 24 h-treatment with CB at different concentrations (0.1–3 μM) on hWJ-MSCs. CB influenced the cytoskeletal organization in a dose-dependent manner, inducing changes in cell number, proliferation, shape, and nanomechanical properties, thus promoting the osteogenic commitment of hWJ-MSCs, as confirmed by the expression analysis of osteogenic/autophagy markers

    Evolution of enhanced innate immune evasion by SARS-CoV-2

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    Emergence of SARS-CoV-2 variants of concern (VOCs) suggests viral adaptation to enhance human-to-human transmission1,2. Although much effort has focused on characterisation of spike changes in VOCs, mutations outside spike likely contribute to adaptation. Here we used unbiased abundance proteomics, phosphoproteomics, RNAseq and viral replication assays to show that isolates of the Alpha (B.1.1.7) variant3 more effectively suppress innate immune responses in airway epithelial cells, compared to first wave isolates. We found that Alpha has dramatically increased subgenomic RNA and protein levels of N, Orf9b and Orf6, all known innate immune antagonists. Expression of Orf9b alone suppressed the innate immune response through interaction with TOM70, a mitochondrial protein required for RNA sensing adaptor MAVS activation. Moreover, the activity of Orf9b and its association with TOM70 was regulated by phosphorylation. We propose that more effective innate immune suppression, through enhanced expression of specific viral antagonist proteins, increases the likelihood of successful Alpha transmission, and may increase in vivo replication and duration of infection4. The importance of mutations outside Spike in adaptation of SARS-CoV-2 to humans is underscored by the observation that similar mutations exist in the Delta and Omicron N/Orf9b regulatory regions

    On the sand response of fracture grouting on a bell tower foundation

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    Fracture grouting is a rather recent technique as a soil reinforcement intervention. Careful and controlled creation of fractures can greatly improve strength and stiff- ness of the treated soils. However, the control of fractures generation is a difficult task, especially in sand where permeation processes and local inhomogeneities play an important role. Recent laboratory tests have enabled to better understand the governing factors of fracturing processes, but field experiences are still rare and the effect of the interventions can hardly be directly analysed. In this paper a fracture grouting intervention, carried out on the foundation soil of the Frari bell tower in Venice (Italy), is described. The field response of the sandy soil was observed and analysed mainly in relation to the results of the in situ-investigations carried out after the intervention. The comparison with the behaviour of the over- lying silty clay layer is also described. The intervention produced different types of soil-grout interactions in sand: a diffused uncemented varved structure, soft lenses of cement, bentonite and sand and local consistent grout lenses. On the contrary, diffused sub-vertical cement lenses were found in clay. The comparison between the results of in situ tests performed at different stages of the intervention show an overall improvement of soil mechanical characteristics. The intervention has proved to be less effective in sand than in clay, also due to the general lower treatment intensity

    Tolerance Scheduling for CPS

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    Scheduling, as a decision-making process, plays a crucial role in manufacturing. Most production systems work in dynamic environments, where disrupting events may result in non-optimality or infeasibilities of the previously defined production schedules. The advent of Cyber Physical Systems (CPS) has brought to higher connectivity and integration of the physical world with the digital world, leading to a higher level of self-awareness and to a new boost in the research interests in reactive scheduling. This work aims at proposing a dynamic scheduling framework based on the tolerance scheduling principle; rescheduling is only triggered in the presence of major disrupting events, accepting a tolerance interval, in order to reduce its frequency. Tolerances for process parameters are defined on the previously selected schedule in order to provide an automated decision-making for triggering the reactive scheduling
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