Ultrasonic force microscopy: detection and imaging of ultra-thin molecular domains

The analysis of the formation of ultra-thin organic films is a very important issue. In fact, it is known that the properties of organic light emitting diodes and field effect transistors are strongly affected by the early growth stages. For instance, in the case of sexithiophene, the presence of domains made of molecules with the backbone parallel to the substrate surface has been indirectly evidenced by photoluminescence spectroscopy and confocal microscopy. On the contrary, conventional scanning force microscopy both in contact and intermittent contact modes have failed to detect such domains. In this paper, we show that Ultrasonic Force Microscopy (UFM), sensitive to nanomechanical properties, allows one to directly identify the structure of sub-monolayer thick films. Sexithiophene flat domains have been imaged for the first time with nanometer scale spatial resolution. A comparison with lateral force and intermittent contact modes has been carried out in order to explain the origins of the UFM contrast and its advantages. In particular, it indicates that UFM is highly suitable for investigations where high sensitivity to material properties, low specimen damage and high spatial resolution are required.     

Multimedia ontology population through semantic analysis and hierarchical deep features extraction techniques

Knowledge and Information Systems - The rapid increase of available data in different complex contexts needs automatic tasks to manage and process contents. Semantic Web technologies represent the...     

A new test scheduling algorithm based on Networks-on-Chip as Test Access Mechanisms

Networks-on-Chip (NoCs) can be used for test data transportation during manufacturing tests. On one hand, NoC can avoid dedicated Test Access Mechanisms (TAMs), reducing long global wires, and potentially simplifying the layout. On the other hand, (a) it is not known how much wiring is saved by reusing NoCs as TAMs, (b) the impact of reuse-based approaches on test time is not clear, and (c) a computer aided test tool must be able to support different types of NoC designs. This paper presents a test environment where the designer can quickly evaluate wiring and test time for different test architectures. Moreover, this paper presents a new test scheduling algorithm for NoC TAMs which does not require any NoC timing detail and it can easily model NoCs of different topologies. The experimental results evaluate the proposed algorithm for NoC TAMs with an exiting algorithm for dedicated TAMs. The results demonstrate that, on average, 24% (up to 58%) of the total global wires can be eliminated if dedicated TAMs are not used. Considering the reduced amount of dedicated test resources with NoC TAM, the test time of NoC TAM is only, on average, 3.88% longer compared to dedicated TAMs.     

Influence of temperature on the liver circadian clock in the ruin lizard Podarcis sicula

Reptiles represent an interesting animal model to investigate the influence of temperature on molecular circadian clocks. The ruin lizard Podarcis sicula lives in a continental climate and it is subjected to wide range of environmental temperatures during the course of the year. As consequence, ruin lizard daily activity pattern includes either the hibernation or periods of inactivity determined by hypothermia. Here we showed the rhythmic expression of two clock genes, lPer2 and lClock, in the liver of active lizards exposed to summer photo-thermoperiodic conditions. Interestingly, the exposition of lizards to hypothermic conditions, typical of winter season, induced a strong dampening of clock genes mRNA rhythmicity with a coincident decrease of levels. We also examined the qualitative and quantitative distribution of lPER2 and lCLOCK protein in different cellular compartments during the 24-h cycle. In the liver of active lizards both proteins showed a rhythmic expression profile in all cellular compartments. After 3 days at 6 degrees C, some temporal fluctuations of the lCLOCK and lPER2 are still detectable, although, with some marked modifications in respect to the values detected in the liver of active lizards. Besides demonstrating the influence of low temperature on the lizard liver circadian oscillators, present results could provide new essential information for comparative studies on the influence of temperature on the circadian system across vertebrate classes.     

Limits of economic and strategic rationality for agents and MA systems

AI adoption of the game-theoretic paradigm although motivated and productive, suffers from basic limits for modelling autonomous agents and MA systems. First, we briefly restate game-theory's role for DAI and MAS: the introduction of formal prototypical social situations (“games”); the use of formal and sound notions, a self-interested view of autonomous agents, etc. Then, a number of criticisms, that have an impact on modelling intelligent social/individual action, are examined: the economicist interpretation of rationality; its instrumentalist conception, which leaves implicit the ends of agents' choices; the consequent multiple equilibria allowed by the theory; the context-unboundedness of rationality. Some contributions for a more heterarchic, context-bounded, architecture of rational agent are given, and a goal-based strategy, as distinct from a strictly utilitarian principle of decision-making, is proposed. Troubles of game-theory with multi-agent systems and in particular with modelling “cooperation” are outlined. Finally, some limits inherent in the notion of “incentive engineering” are pointed out.     

Discovery of an Allosteric Ligand Binding Site in SMYD3 Lysine Methyltransferase

SMYD3 is a multifunctional epigenetic enzyme with lysine methyltransferase activity and various interaction partners. It is implicated in the pathophysiology of cancers but with an unclear mechanism. To discover tool compounds for clarifying its biochemistry and potential as a therapeutic target, a set of drug-like compounds was screened in a biosensor-based competition assay. Diperodon was identified as an allosteric ligand; its R and S enantiomers were isolated, and their affinities to SMYD3 were determined (K_D=42 and 84 μM, respectively). Co-crystallization revealed that both enantiomers bind to a previously unidentified allosteric site in the C-terminal protein binding domain, consistent with its weak inhibitory effect. No competition between diperodon and HSP90 (a known SMYD3 interaction partner) was observed although SMYD3–HSP90 binding was confirmed (K_D=13 μM). Diperodon clearly represents a novel starting point for the design of tool compounds interacting with a druggable allosteric site, suitable for the exploration of noncatalytic SMYD3 functions and therapeutics with new mechanisms of action.     

Knowledge Acquisition and Design Using Semantics and Perception: A Case Study for Autonomous Robots

Neural Processing Letters - The pervasive use of artificial intelligence and neural networks in several different research fields has noticeably improved multiple aspects of human life. The...     

Dual‐Layer Hollow Fibers for Sulfur Removal from Fuels

Emission of sulfur compounds to the atmosphere is universally recognized as one key target to be reduced. For membrane pervaporation which is considered as a potential purification process of fuels, dual‐layer polyurethane (PU)/polyethersulfone hollow‐fiber membranes were prepared. A novel fabrication technique is proposed using a quadruple spinneret to produce the fiber with such morphology by simultaneous spinning of two polymer solutions in the presence of two corresponding precipitation media. Activated carbon was added into the PU solution to improve the transport properties of the selective layer. Resulting hollow‐fiber membranes showed very good adhesion between the selective layer and its support, in addition to an effective removal of a sulfur compound such as 2‐methyl thiophene from a typical model fuel, an indication of good prospects for both the fabrication technique and for sulfur removal by pervaporation of fuels.     

Heuristic approaches for the optimal wiring in large scale robotic skin design

This paper faces the problem of optimizing the wiring and the connections in a tactile skin for robots. The robotic skin is a device composed of a network of tactile sensors, whose wiring can be very complex: the control of this complexity is a key problem. In the considered robotic skin, skin elements are grouped into skin patches, which output tactile data that have to be read by a micro-controller. The logical connections between the sensors must be defined in order to route signals through the network. A finite set of micro-controllers is given and a set of constraints is imposed on the given assignment and routing. The considered problem has a combinatorial nature and it can be formulated as a Minimum Constrained Spanning Forest problem with costs on arcs that cannot be a priori defined as they are solution-dependent. The problem is NP-hard. The paper introduces a mathematical formulation and then proposes a Multi-Start Heuristic algorithm and an Ant Colony Optimization approach whose effectiveness is evaluated through experimental tests performed on both real and synthetically generated instances.