Artificial receptors for artificial olfaction

Any attempt to mimic the behavior of natural olfaction is mainly based on the properties of the artificial sensor units. Since the beginning of artificial olfaction, the main requirement for sensors has been the partial crossselectivity. This trivial feature makes possible the application of the combinatorial selectivity principle to the arrays of gas sensors. The principle of cross-selectivity can actually be fulfilled by almost any kind of sensor technology. This resulted in a vast popularity of "electronic noses" and their application. However, it is important to consider the kind of the cross-selectivity offered by sensors technology. Current sensors combines together the capability of chemistry to synthesize molecules endowed with molecular recognition properties and a number of solid-state devices that actually measure the changes in some physical properties consequent to the chemical interaction event. From this point of view, it is important to consider that in practice a number of unwanted interaction can take place even if the receptor is designed to emphasize the selectivity towards a particular kind of molecule. These are mainly driven by Van der Waals forces. Most of the available transducers cannot discriminate interactions by their energy and since Van der Waals interactions are rather ubiquitous the sensors tend to be highly correlated. A scrutiny of literature on electronic noses shows that even in case of large arrays, PCA often is limited to two variables. In this presentation, these principles will be discussed considering the study case of metalloporphyrins. These are a rather versatile class of molecules whose gas sensing properties are actively exploited in Nature, for instance for the transport of molecules such as O2 and N2 in blood. The possibility to reduce the influence of common interactions will be illustrated. It has also to be considered that the reduction of correlation is necessary to increase the array size in artificial olfaction systems. Published: 16 April 201

From "Gomorrah Domain" to "Don Peppe Diana Lands". A Southern Italian Experience of Work-Based Liberation, Community Networking, and Well Being

The article describes working experiences in relation to empowering activities, which have been carried out in a local community in the province of Caserta (in Southern Italy), a place characterized by the widespread presence of organized criminal groups. In this study, workplace is intended as a community network aimed at the promotion of coscientization, liberation, and well-being. Specifically, this paper features initiatives and projects aimed at establishing new community values through a re-construction of a work-based social system standing against criminal clans, which tend to dominate not only economical transactions but also civil life

Mirabilia Coralii. Capolavori barocchi in corallo tra maestranze ebraiche e trapanesi

La pregevole lavorazione del corallo trapanese ricostruita attraverso la puntuale analisi delle fonti documentarie, manoscritte e bibliografiche. L’organizzazione della maestranza e il ruolo che la committenza,sia laica che ecclesiastica, ha esercitato nella realizzazione di capolavori oggi presenti in rinomate collezioni pubbliche e private e nei principali musei nazionali ed internazionali. Una rassegna di importanti manufatti, un tempo mirabili opere da Wunderkammer, criticamente commentata, che bene evidenzia l’aulica produzione siciliana ricercata da Sovrani, Viceré ed alti prelati. Un’originale ed inedita trattazione che per la prima volta rende noti nomi e biografie di gran parte degli artisti specializzati, tra XVI e XIX secolo, nella trasformazione del prezioso materiale marin

Structural investigation of nucleophosmin interaction with the tumor suppressor Fbw7γ

Nucleophosmin (NPM1) is a multifunctional nucleolar protein implicated in ribogenesis, centrosome duplication, cell cycle control, regulation of DNA repair and apoptotic response to stress stimuli. The majority of these functions are played through the interactions with a variety of protein partners. NPM1 is frequently overexpressed in solid tumors of different histological origin. Furthermore NPM1 is the most frequently mutated protein in acute myeloid leukemia (AML) patients. Mutations map to the C-terminal domain and lead to the aberrant and stable localization of the protein in the cytoplasm of leukemic blasts. Among NPM1 protein partners, a pivotal role is played by the tumor suppressor Fbw7γ, an E3-ubiquitin ligase that degrades oncoproteins like c-MYC, cyclin E, Notch and c-jun. In AML with NPM1 mutations, Fbw7γ is degraded following its abnormal cytosolic delocalization by mutated NPM1. This mechanism also applies to other tumor suppressors and it has been suggested that it may play a key role in leukemogenesis. Here we analyse the interaction between NPM1 and Fbw7γ, by identifying the protein surfaces implicated in recognition and key aminoacids involved. Based on the results of computational methods, we propose a structural model for the interaction, which is substantiated by experimental findings on several site-directed mutants. We also extend the analysis to two other NPM1 partners (HIV Tat and CENP-W) and conclude that NPM1 uses the same molecular surface as a platform for recognizing different protein partners. We suggest that this region of NPM1 may be targeted for cancer treatment

Strength is in numbers: Can concordant artificial listeners improve prediction of emotion from speech?

Humans can communicate their emotions by modulating facial expressions or the tone of their voice. Albeit numerous applications exist that enable machines to read facial emotions and recognize the content of verbal messages, methods for speech emotion recognition are still in their infancy. Yet, fast and reliable applications for emotion recognition are the obvious advancement of present 'intelligent personal assistants', and may have countless applications in diagnostics, rehabilitation and research. Taking inspiration from the dynamics of human group decision-making, we devised a novel speech emotion recognition system that applies, for the first time, a semi-supervised prediction model based on consensus. Three tests were carried out to compare this algorithm with traditional approaches. Labeling performances relative to a public database of spontaneous speeches are reported. The novel system appears to be fast, robust and less computationally demanding than traditional methods, allowing for easier implementation in portable voice-analyzers (as used in rehabilitation, research, industry, etc.) and for applications in the research domain (such as real-time pairing of stimuli to participants' emotional state, selective/differential data collection based on emotional content, etc.)

The long-lasting story of one sensor development: from novel ionophore design toward the sensor selectivity modeling and lifetime improvement

The metalloporphyrin ligand bearing incorporated anion-exchanger fragment, 5-[4-(3-trimethylammonium)propyloxyphenyl]-10,15,20-triphenylporphyrinate of Co(II) chloride, CoTPP-N, has been tested as anion-selective ionophore in PVC-based solvent polymeric membrane sensors. A plausible sensor working mechanism includes the axial coordination of the target anion on ionophore metal center followed by the formed complex aggregation with the second ionophore molecule through positively charged anion-exchanger fragment. The UV-visible spectroscopic studies in solution have revealed that the analyte concentration increase induces the J-type porphyrin aggregation. Polymeric membranes doped with CoTPP-N showed close to the theoretical Nernstian response toward nitrite ion, preferably coordinated by the ionophore, and were dependent on the presence of additional membrane-active components (lipophilic ionic sites and ionophore) in the membrane phase. The resulting selectivity was a subject of specific interaction and/or steric factors. Moreover, it was demonstrated theoretically and confirmed experimentally that the selection of a proper ratio of ionophore and anionic additive can optimize the sensor selectivity and lifetime

An Ensemble of Adaptive Classifiers for Improving Faulty and Drifting Sensor Performance

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Sensor-embedded face masks for detection of volatiles in breath: a proof of concept study

The correlation between breath volatilome and health is prompting a growing interest in the development of sensors optimized for breath analysis. On the other hand, the outbreak of COVID-19 evidenced that breath is a vehicle of infection; thus, the introduction of low-cost and disposable devices is becoming urgent for a clinical implementation of breath analysis. In this paper, a proof of concept about the functionalization of face masks is provided. Porphyrin-based sensors are among the most performant devices for breath analysis, but since porphyrins are scarcely conductive, they make use of costly and bulky mass or optical transducers. To overcome this drawback, we introduce here a hybrid material made of conducting polymer and porphyrins. The resulting material can be easily deposited on the internal surface of standard FFP face masks producing resistive sensors that retain the chemical sensitivity of porphyrins implementing their combinatorial selectivity for the identification of volatile compounds and the classification of complex samples. The sensitivity of sensors has been tested with respect to a set of seven volatile compounds representative of diverse chemical families. Sensors react to all compounds but with a different sensitivity pattern. Functionalized face masks have been tested in a proof-of-concept test aimed at identifying changes of breath due to the ingestion of beverages (coffee and wine) and solid food (banana- and mint-flavored candies). Results indicate that sensors can detect volatile compounds against the background of normal breath VOCs, suggesting the possibility to embed sensors in face masks for extensive breath analysis

Self-adaptive thermal modulation of gas sensors

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