A cube to learn: a tangible user interface for the design of a learning appliance

In this paper we introduce the design and development of the Learning Cube as a novel tangible learning appliance. Using the common shape of a cube we implemented a general learning platform that supports test based quizzes where questions and answers can be text or image based. Exploiting the physical affordances of the cube and augmenting it with embedded sensors and LCD displays placed on each face, we present different learning appliances as playful learning interfaces for children. Based on the initial observations of the experience with children, we argue that breaking conventions about how a computer has to look like, and providing children with a playful interface is a promising approach to embed and integrate technology into children’s everyday context and activities.     

New signaling molecules in some gram-positive and gram-negative bacteria

A new family of putative signaling molecules having a 2(5H)-furanone configuration has been described in this work. They were released during late exponential or stationary phase in different growth media by some gram-positive bacteria, such as Lactobacillus helveticus, Lactobacillus plantarum, Lactobacillus paraplantarum, Lactobacillus sanfranciscensis, Enterococcus faecalis, and a gram-negative species, i.e. Salmonella enterica. A pair of 2(5H)-furanones called furanones A and B occurred in all the conditioned media (CMs) of the species considered. These two molecules showed similar retention times and their spectral data shared the key fragments to include them in the 2(5H)-furanones family. However, some differences were observed in the mass fragmentation profiles. In particular the use of PCA analysis of all the mass fragments enabled the grouping of furanone A profiles of S. enterica, L. helveticus, L. plantarum, L. paraplantarum, L. sanfranciscensis and E. faecalis in one unique cluster with only few exceptions. On the other hand, the mass fragmentation profiles of furanone B of the major part of the species and strains could be grouped together and were differentiated from those of L. helveticus. The specific activity of cell-free supernatants of high density cultures of S. enterica confirmed that the release of active molecules, and specifically of furanones A and B, was cell density dependent. Moreover, a preliminary experiment suspending S. enterica cells into cell-free supernatants of L. helveticus previously exposed to an oxidative stress demonstrated that furanones A and B have a strong interspecific activity. In fact cell autolysis and cell envelope damages were observed with Scanning Electron Microscopy (SEM) in S. enterica.     

Scanning gate imaging of quantum point contacts and the origin of the 0.7 anomaly

The origin of the anomalous transport feature appearing at a conductance G ≈ 0.7 × (2e²/h) in quasi-1D ballistic devices-the so-called 0.7 anomaly-represents a long standing puzzle. Several mechanisms have been proposed to explain it, but a general consensus has not been achieved. Proposed explanations have been based on quantum interference, the Kondo effect, Wigner crystallization, and other phenomena. A key open issue is whether the point defects that can occur in these low-dimensional devices are the physical cause behind this conductance anomaly. Here we adopt a scanning gate microscopy technique to map individual impurity positions in several quasi-1D constrictions and correlate these with conductance characteristics. Our data demonstrate that the 0.7 anomaly can be observed irrespective of the presence of localized defects, and we conclude that the 0.7 anomaly is a fundamental property of low-dimensional systems.

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Inkjet‐Printed Multicolor Arrays of Highly Luminescent Nanocrystal‐Based Nanocomposites

Inkjet technology is a compelling method for the flexible and cost‐effective printing of functional inks. We show that nanocomposite solutions based on polystyrene and differently sized core/shell‐type nanocrystals (NCs) formed by a CdSe core coated with a shell of ZnS (CdSe@ZnS) in a single solvent, chloroform, can be reliably dispensed into luminescent, multicolor pixel arrays. This study demonstrates the relevance of parameters like polymer concentration and nozzle diameter, highlighting how the optimal conditions to print NCs embedded in 5 wt% polystyrene nanocomposite are given by a 70‐µm‐diameter nozzle. The obtained structures show that the bright size‐dependent emission of the NCs in the nanocomposite is retained in the printed pixels.     

An Interview with Giorgio Grassi

In January 2007, Lucia Tozzi visited Giorgio Grassi's office in Milan. Their conversation touched on Grassi's recent work on Leon Battista Alberti, which is examined here in the context of Grassi's obliquely expressed views on contemporary architecture and the cult of personality. As perhaps the most intellectually rigorous and formally consistent Rationalist architect of his generation, Grassi's work and thinking retain a hermetic aspect, but one notable for its philosophical self-questioning and underlying political commitment. Copyright © 2007 John Wiley & Sons, Ltd.     

Selected Italian Projects

Rationalism remains at the sidelines of contemporary architecture in Italy – a latent current rather than a leading force. Andrew Peckham and Lucia Tozzi reveal how this stubborn but rich seam is manifesting itself: in Cino Zucchi's substantial housing scheme on the outskirts of Milan; Werner Tscholl's insertion into Schloss Sigmundskron/Castel Firmiano; Beniamino Servino's continued work on the Nursery School in Formicola, Caserta; and C+S Associati's Nursery School at Covolo di Pederobba in Treviso. Copyright © 2007 John Wiley & Sons, Ltd.     

In Silico Analysis of Enzyme Surface and Glycosylation Effect as a Tool for Efficient Covalent Immobilisation of CalB and PGA on Sepabeads®

This study presents a computational analysis of the structures of lipase B from Candida antarctica (CalB) and two penicillin G acylases (PGAs), from eukaryotic and prokaryotic sources, respectively. Molecular simulations were used to point out the regions of the enzymes that are prone to interact with immobilisation supports. In order to evaluate the accessibility of the active site, the location of the amino acid residues involved in the formation of covalent bonds with the polymers was visualised. The mapping of the distribution of hydrophobic and hydrophilic regions on the enzyme surface provided a view of the areas of the protein that can establish either hydrophobic or hydrophilic interactions with the carriers. Experimental data obtained from the immobilisation of the enzymes on supports bearing different chemical functionalities suggest the involvement of the glycan moiety in enzyme–polymer interactions. In the case of PGA the glycan moiety can constitute an extra site for the covalent linkage of the enzyme on the polymer.     

Stability analysis and time domain simulation of multiple diameter parts during infeed centerless grinding

Multiple diameter part applications cope a relevant percentage of infeed centerless grinding operations. Nevertheless, general stability analysis and process optimisation has been mainly investigated for mono-diameter parts. This paper presents a time domain simulation software developed for multiple diameter parts that allows the simulation of average and particular evolution of process forces, power, machine deflections, thermal behaviour, real part diameter and roughness. First, a work rotation stability analysis is carried out. Then, with the use of both the stability analysis and the infeed cycle simulation, optimized process parameters and cycles are defined in order to increase process productivity.