725 research outputs found
One-Dimensional Nanostructured Oxide Chemoresistive Sensors
No full textDay by day, the demand for portable, low cost, and efficient chemical/gas-sensing devices is increasing due to worldwide industrial growth for various purposes such as environmental monitoring and health care. To fulfill this demand, nanostructured metal oxides can be used as active materials for chemical/gas sensors due to their high crystallinity, remarkable physical/chemical properties, ease of synthesis, and low cost. In particular, (1D) one-dimensional metal oxides nanostructures, such as nanowires, exhibit a fast response, selectivity, and stability due to their high surface-to-volume ratio, well-defined crystal orientations, controlled unidirectional electrical properties, and self-heating phenomenon. Moreover, with the availability of large-scale production methods for nanowire growth such as thermal oxidation and evaporation-condensation growth, the development of highly efficient, low cost, portable, and stable chemical sensing devices is possible. In the last two decades, tremendous advances have been achieved in 1D nanostructured gas sensors ever since the pioneering work by Comini on the development of a SnO2 nanobelt for gas sensor applications in 2002, which is one such example from which many researchers began to explore the field of 1D-nanostructure-based chemical/gas sensors. The Sensor Laboratory (University of Brescia) has made major contributions to the field of metal oxide nanowire chemical/gas-sensing devices. Over the years, different metal oxides such as SnO2, ZnO, WO3, NiO, CuO, and their heterostructures have been grown for their nanowire morphology and successfully integrated into chemoresistive gas-sensing devices. Hence in this invited feature article, Sensor Laboratory research on the synthesis of metal oxide nanowires and novel heterostructures and their characterization and gas-sensing performance during exposure to different gas analytes has been presented. Moreover, some new strategies such as branched-like nanowire heterostructures and core-shell nanowire structures adopted to enhance the performance of nanowire-based chemical sensor are presented in detail
Exposure to the agricultural fungicide tebuconazole promotes Aspergillus fumigatus cross-resistance to clinical azoles. [Comini S. is the co-first author; Banche G. is the corresponding author; Cuffini A.M. is the co-corresponding author]
No full textResistance to clinical triazoles in Aspergillus fumigatus is a growing concern for individuals at high risk of Aspergillus infection. Two triazole resistance selection routes are currently being investigated: one occurring in triazole-treated patients in healthcare settings, and the second taking place in the environment due to the widespread use of agricultural triazoles. This study aimed to assess the ability of agricultural azoles to promote cross-resistance to clinical azoles in A. fumigatus. Five A. fumigatus isolates susceptible to clinical azoles were exposed to the triazole 14α-demethylase inhibitor, tebuconazole (TBC), and then antifungal susceptibility tests for voriconazole, itraconazole, posaconazole and isavuconazole were performed. Under TBC selection pressure, all A. fumigatus isolates exhibited resistance to clinical triazoles. However, only two displayed a multiresistant phenotype to clinical azoles. TBC exposure was also associated with delayed conidia formation and progressive absence of conidiation. Noteworthy, no TBC-exposed clones harbored TR34/L98H mutation, as judged by real-time PCR assays. The observation that TBC exposure promotes cross-resistance to clinical triazoles warrants careful and thorough assessment of the human health risk associated with agricultural azoles. The absence of TR34/L98H mutation in cross-resistant A. fumigatus isolates suggests that other cyp51A mutations may be involved in clinical azole cross-resistance
Evaluation of the Amplex eazyplex SuperBug Acineto test for direct detection of multidrug- resistant Acinetobacter baumannii bloodstream infections in high endemicity settings [S. Comini is the corresponding author]
No full textLogic programs as specifications in the inductive verification of logic programs
No full textIn this paper we define a new verification method based on an assertion language able to express properties defined by the user through a logic program. We first apply the verification framework defined in another paper of ours to derive sufficient inductive conditions to prove partial correctness. Then we show how the resulting conditions can be proved using program transformation techniques
SiC Foams Decorated with SnO2 Nanostructures for Room Temperature Gas Sensing
No full textSberveglieri, Giorgio/0000-0003-0080-8117; Ponzoni, Andrea/0000-0001-9955-5118; Comini, Elisabetta/0000-0003-2559-5197; Vakifahmetoglu, Cekdar/0000-0003-1222-4362Cell walls of the commercial silicon carbide (SiC)-based foams were decorated by one-dimensional tin dioxide (SnO2) nanostructures. Thermal evaporation of SnO2 powder with the assistance of a Au catalyst in inert atmosphere caused the formation of SnO2 nanobelts on the pore surfaces. The room temperature (RT) ammonia (NH3) and nitrogen dioxide (NO2) gas sensing behaviors were investigated systematically in both dry and humid air atmosphere with/without UV activation. The results were compared to those for bare SnO2 and SiC. It was shown that SiC/SnO2 composite was efficient to detect low concentration of NH3 (10-50 ppm) and NO2 (1-5 ppm) under humid air and UV activation at RT.TUBITAK (The Scientific and Technological Research Council of Turkey)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [CAYDAG-113Y533]The author wishes to express sincere appreciation to Prof. Gian Domenico Soraru and his team in University of Trento for the N2 adsorption and desorption data. C. V. gratefully acknowledge the support of TUBITAK (The Scientific and Technological Research Council of Turkey) under the project Grant No. CAYDAG-113Y533
Growth Processing and Strategies: A Way to Improve the Gas Sensing Performance of Nickel Oxide-Based Devices
No full textThe review paper provides a comprehensive analysis of nickel oxide (NiO) as an emerging material in environmental monitoring by surveying recent developments primarily within the last three years and reports the growth processing and strategies employed to enhance NiO sensing performance. It covers synthesis methods for pristine NiO, including vapor-phase, liquid-phase, and solution-processing techniques, highlighting advantages and limitations. The growth mechanisms of NiO nanostructures are explored, with a focus on the most recent research studies. Additionally, different strategies to improve the gas sensing performance of NiO are discussed (i.e., surface functionalization by metallic nanoparticles, heterostructure formation, carbon-based nanomaterials, and conducting polymers). The influence of these strategies on selectivity, sensitivity, response time, and stability of NiO-based sensors is thoroughly examined. Finally, the challenges and future directions that may lead to the successful development of highly efficient NiO-based gas sensors for environmental monitoring are introduced in this review
A theory of observables for logic programs
No full textWe define a semantic framework to reason about properties of abstractions of SLD-derivations. The framework allows us to address problems such as the relation between the (top-down) operational semantics and the (bottom-up) denotational. semantics, the existence of a denotation for a set of definite clauses and their properties (compositionality w.r.t. various syntactic operators, correctness, minimality, and precision). Using abstract interpretation techniques to model abstraction allows us to state very simple conditions on the observables which guarantee the validity of several general theorems. (C) 2001 Academic Press
Assertion based Inductive Verification Methods for Logic Programs
No full texthis paper is an overview of our results on the application of abstract interpretation concepts to the derivation of a verification method for logic programs. These include the systematic design of semantics modeling various proof methods and the characterization of assertions as abstract domains. We first apply the verification framework defined in [5] to derive inductive sufficient conditions for partial correctness. Then the domain of assertions is formalized as an abstract domain. We can therefore derive an assertion based verification method. We finally show two methods based on different assertion languages: a decidable assertion language and Horn clause logic used as assertion language
Reflexiones periféricas sobre las disyuntivas identitarias de una Europa en crisis: oscilaciones de un sueño paneuropeo cargado de una compleja vanidad
No full textComini, Nicolás M. Licenciado en Relaciones Internacionales (Universidad del Salvador); Becario doctoral del Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y docente titular de cátedra de Política Internacional Contemporánea y Teoría de las Relaciones Internacionales II y III (Universidad del Salvador)Bontempo, Tomas. Licenciado en Relaciones Internacionales (Universidad del Salvador); Docente adjunto e investigador de la cátedra de Teoría de las Relaciones Internacionales II y III (IDICSO/USAL) y Maestrando en Integración Latinoamericana (Universidad Nacional de Tres de Febrero - UNTREF
Abstract diagnosis
No full textWe show how declarative diagnosis techniques can be extended to cope with verification of operational properties, such as computed and correct answers, and of abstract properties, such as depth(k) answers and groundness dependencies. The extension is achieved by using a simple semantic framework, based on abstract interpretation. The resulting technique (abstract diagnosis) leads to elegant bottom-up and top-down verification methods, which do not require to determine the symptoms in advance, and which are effective in the case of abstract properties described by finite domains. (C) 1999 Elsevier Science Inc. All rights reserved
- …
