Parallel Implementation of a Machine Learning Algorithm on GPU

The capability for understanding data passes through the ability of producing an effective and fast classification of the information in a time frame that allows to keep and preserve the value of the information itself and its potential. Machine learning explores the study and construction of algorithms that can learn from and make predictions on data. A powerful tool is provided by self-organizing maps (SOM). The goal of learning in the self-organizing map is to cause different parts of the network to respond similarly to certain input patterns. Because of its time complexity, often using this method is a critical challenge. In this paper we propose a parallel implementation for the SOM algorithm, using parallel processor architecture, as modern graphics processing units by CUDA. Experimental results show improvements in terms of execution time, with a promising speed up, compared to the CPU version and the widely used package SOM_PAK.     

A synthetic biology approach to bio-chem-ICT: first moves towards chemical communication between synthetic and natural cells

In this article we present novel aspects of the impact that synthetic biology (SB) can express in a field traditionally based on computer science: information and communication technologies (ICTs), an area that we will consider taking into account also possible implications for artificial intelligence (AI) research. In the first part of this article we will shortly introduce some recent theoretical and experimental issues related to our approach in SB, discussing their relevance and potentiality in the field. Next, we define an original SB research programme that aims at contributing to the development of bio-chem-ICTs and AI based on chemical communication between natural and synthetic cells. In particular we present (i) a mathematical model that allows us to simulate the main features of the system under construction; and (ii) preliminary wet-lab experiments showing the feasibility of our research programme. Based on the bottom-up construction of synthetic cells, the traits of this novel approach and their connections with recent conceptual and technological trends are finally discussed.     

The effect of the conditions of electrodeposition on the capacitive properties of dinitrobenzoyl-derivative polypyrrole films

Films of poly[(R)-(−)-3-(1-pyrrolyl)propyl-N-(3,5-dinitrobenzoyl)-α-phenylglycinate] (polyDNBP) were deposited, using the galvanostatic method, onto indium tin oxide electrodes in the presence of the electrolytes tetrabutylammonium tetrafluoro-borate [(C₄H₉)₄NBF₄] or LiClO₄. Atomic force microscopy revealed that polyDNBP/(C₄H₉)₄NBF₄ films exhibited a grainy morphology with higher roughness and greater superficial area than polyDNBP/LiClO₄ films. Moreover, polyDNBP/(C₄H₉)₄NBF₄ films exhibited a higher capacitive electrochemical response when characterised in LiClO₄ rather than in (C₄H₉)₄NBF₄. Since polyDNBP films exhibit both n- and p-doping, they may have considerable potential application as electrodes in type III capacitor assemblies.     

The balance of give and take in caregiver–partner relationships: An examination of self-perceived burden, relationship equity, and quality of life from the perspective of care recipients following stroke.

Purpose: We examined the sense of being a burden to others or self-perceived burden (SPB) in people with stroke. Method: A mail survey was completed by 57 former inpatients and their partner caregivers. The care recipient survey included measures of functional status, quality of life, marital satisfaction, equity in the relationship, and psychological distress, as well as SPB using the Self-Perceived Burden Scale (SPBS; Cousineau, McDowell, Hotz, & Hébert, 2003). The caregiver survey included similar measures in addition to a caregiver burden measure. Results: SPB was found to be a prevalent and distressing concern. SPBS scores correlated with measures of functional status and mood; however, the correlations were highest for measures of family roles and work/productivity. Using equity theory as a basis to examine the SPB construct, care recipients who perceived themselves as overbenefiting from the relationship had significantly higher SPB scores than those whose relationship was viewed as equitable or underbenefiting. Conclusions: For some receiving care from a partner after stroke is associated SPB. This sense of burden is related to changes in help-seeking behavior, quality of life, and distress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fluidic Force Microscopy and Atomic Force Microscopy Unveil New Insights into the Interactions of Preosteoblasts with 3D-Printed Submicron Patterns

Physical patterns represent potential surface cues for promoting osteogenic differentiation of stem cells and improving osseointegration of orthopedic implants. Understanding the early cell–surface interactions and their effects on late cellular functions is essential for a rational design of such topographies, yet still elusive. In this work, fluidic force microscopy (FluidFM) and atomic force microscopy (AFM) combined with optical and electron microscopy are used to quantitatively investigate the interaction of preosteoblasts with 3D-printed patterns after 4 and 24 h of culture. The patterns consist of pillars with the same diameter (200 nm) and interspace (700 nm) but distinct heights (500 and 1000 nm) and osteogenic properties. FluidFM reveals a higher cell adhesion strength after 24 h of culture on the taller pillars (32 ± 7 kPa versus 21.5 ± 12.5 kPa). This is associated with attachment of cells partly on the sidewalls of these pillars, thus requiring larger normal forces for detachment. Furthermore, the higher resistance to shear forces observed for these cells indicates an enhanced anchorage and can be related to the persistence and stability of lamellipodia. The study explains the differential cell adhesion behavior induced by different pillar heights, enabling advancements in the rational design of osteogenic patterns.     

Magnetoresistance in Sn-Doped In2O3 Nanowires

In this work, we present transport measurements of individual Sn-doped In₂O₃ nanowires as a function of temperature and magnetic field. The results showed a localized character of the resistivity at low temperatures as evidenced by the presence of a negative temperature coefficient resistance in temperatures lower than 77 K. The weak localization was pointed as the mechanism responsible by the negative temperature coefficient of the resistance at low temperatures.     

Nano-assembled Pd catalysts on MgO thin films

Cluster-assembled materials open fascinating new routes for tuning physical and chemical properties by changing cluster size and often behave completely differently than their bulk analogues. By depositing gas phase Pd clusters on MgO thin films, model catalysts are fabricated which exhibit remarkable catalytic activity. In contrast to the high selectivity of Pd (111) surfaces for the cyclotrimerization of acetylene to benzene, small supported Pd_n clusters reveal a strongly size-dependent selectivity and catalyse the formation of benzene as well as of other hydrocarbons. The understanding at the atomistic level of the observed processes has been obtained by means of first-principles quantum–mechanical simulations. The theoretical studies have shown the importance of the surface defects of the oxide substrate in stabilizing the supported clusters but also in promoting their catalytic activity. For instance, Pd atoms bound at the regular sites of the MgO (100) terraces do not promote the acetylene to benzene conversion while they become active catalysts when bound at oxygen vacancies (F centers).