Identifying Geographic Clusters: A Network Analytic Approach

In recent years there has been a growing interest in the role of networks and clusters in the global economy. Despite being a popular research topic in economics, sociology and urban studies, geographical clustering of human activity has often studied been by means of predetermined geographical units such as administrative divisions and metropolitan areas. This approach is intrinsically time invariant and it does not allow one to differentiate between different activities. Our goal in this paper is to present a new methodology for identifying clusters, that can be applied to different empirical settings. We use a graph approach based on k-shell decomposition to analyze world biomedical research clusters based on PubMed scientific publications. We identify research institutions and locate their activities in geographical clusters. Leading areas of scientific production and their top performing research institutions are consistently identified at different geographic scales

Sensor array and gas chromatographic detection of the blood serum volatolomic signature of COVID-19

Volatolomics is gaining consideration as a viable approach to diagnose several diseases, and it also shows promising results to discriminate COVID-19 patients via breath analysis. This paper extends the study of the relationship between volatile compounds (VOCs) and COVID-19 to blood serum. Blood samples were collected from subjects recruited at the emergency department of a large public hospital. The VOCs were analyzed with a gas chromatography mass spectrometer (GC/MS). GC/MS data show that in more than 100 different VOCs, the pattern of abundances of 17 compounds identifies COVID-19 from non-COVID with an accuracy of 89% (sensitivity 94% and specificity 83%). GC/MS analysis was complemented by an array of gas sensors whose data achieved an accuracy of 89% (sensitivity 94% and specificity 80%)

Light-activated porphyrinoid-capped nanoparticles for gas sensing

The coupling of semiconductors with organic molecules results in a class of sensors whose chemoresistive properties are dictated by the nature of dyes. Organic molecules generally reduce conductivity, but in the case of optically active dyes, such as porphyrinoids, the conductivity is restored by illumination with visible light. In this paper, we investigated the gas sensing properties of ZnO nanoparticles coated with porphyrins and corroles. Under light illumination, the resistance of these materials increases with the adsorption of volatile compounds but decreases when these are strong electron donors. The behavior of these sensors can be explicated on the basis of the structural difference between free-base porphyrin and corrole, the influence of coordinated metal, and the corresponding electronic structures. These sensors are promising electronic noses that combine the selectivity to strong electron donors with the broad selectivity toward the other classes of chemicals. An efficient representation of the data of this peculiar array can be obtained by replacing the Euclidean distance with the angular distance. To this end, a recently introduced spherical principal component analysis algorithm is applied for the first time to gas sensor array data. Results show that a minimal gas sensor array (four elements) can produce a sort of chemotopic map, which enables us to cluster a very large class of pure chemical vapors. Furthermore, this map provides information about the composition of complex odor matrices, such as the headspaces of beef meat and their evolution over the time

Identifying geographic clusters: A network analytic approach

In recent years there has been a growing interest in the role of networks and clusters in the global economy. Despite being a popular research topic in economics, sociology and urban studies, geographical clustering of human activity has often been studied by means of predetermined geographical units, such as administrative divisions and metropolitan areas. This approach is intrinsically time invariant and it does not allow one to differentiate between different activities. Our goal in this paper is to present a new methodology for identifying clusters, that can be applied to different empirical settings. We use a graph approach based on k-shell decomposition to analyze world biomedical research clusters based on PubMed scientific publications. We identify research institutions and locate their activities in geographical clusters. Leading areas of scientific production and their top performing research institutions are consistently identified at different geographic scales.publisher: Elsevier articletitle: Identifying geographic clusters: A network analytic approach journaltitle: Research Policy articlelink: http://dx.doi.org/10.1016/j.respol.2015.01.011 content_type: article copyright: Copyright © 2015 Elsevier B.V. All rights reserved.status: publishe

Sensors for Lung Cancer Diagnosis

The positive outcome of lung cancer treatment is strongly related to the earliness of the diagnosis. Thus, there is a strong requirement for technologies that could provide an early detection of cancer. The concept of early diagnosis is immediately extended to large population screening, and then, it is strongly related to non-invasiveness and low cost. Sensor technology takes advantage of the microelectronics revolution, and then, it promises to develop devices sufficiently sensitive to detect lung cancer biomarkers. A number of biosensors for the detection of cancer-related proteins have been demonstrated in recent years. At the same time, the interest is growing towards the analysis of volatile metabolites that could be measured directly from the breath. In this paper, a review of the state-of-the-art of biosensors and volatile compound sensors is presented

Sviluppo del sistema costiero di previsione dello stato del mare

La simulazione della generazione e propagazione del moto ondoso associato al vento è un campo di applicazione che, nell’ultimo decennio, ha avuto ampio sviluppo. Nonostante importanti aspetti delle onde ancora poco noti, il forecast dello stato del mare, grazie allo sviluppo di modelli numerici in grado di simulare accuratamente i complessi processi che regolano l’evoluzione dello spettro energetico delle onde, è un prodotto ormai consolidato per tutti i centri meteorologici. Per capire e prevedere lo stato del mare è stato realizzato un sistema costiero in grado di descrivere gli effetti della propagazione ondosa in sei aree costiere italiane, partendo dalle previsioni sull’intero Mar Mediterraneo

An array of capacitive sensors based on a commercial fingerprint detectors

Capacitance transduction is one of the many possibilities to translate a chemical binding event into an electric signal. However, only few examples of capacitive sensors have been presented because of the complex measurement set-up. Microfabrication offered recently the possibility to develop capacitive sensors but the technology is not available to all the researchers that necessitate to quickly test the sensing materials. Recently, as witnessed with optical sensors, low-cost fingerprint detectors have been released on the market and are currently widely available. Such detectors offer a flat surface endowed with thousands of capacitors that can be functionalized with chemical sensing layers to become chemical sensors. In this paper a demonstration of the possibilities of this technology is shown considering as sensing layer a number of metalloporphyrins, a material yet studied for chemical sensors development. Results show that a good detection of carbon monoxide, ethanol and triethylamine is achieved. The large number of sensors allows also to exploite a number of paradigms learnt from the physiology of olfaction

An exploration of the metal dependent selectivity of a metalloporphyrins coated quartz microbalances array

Several studies in the last two decades have demonstrated that metalloporphyrins coated quartz microbalances can be fruitfully used in many diverse applications, spanning from medical diagnosis to environmental control. This large versatility is due to the combination of the flexibility of metalloporphyrins molecular design with the independence of the quartz microbalance signal from the interaction mechanisms. The nature of the metal atom in the metalloporphyrins is often indicated as one of the most effective tools to design differently selective sensors. However, the properties of sensors are also strongly affected by the characteristics of the transducer. In this paper, the role of the metal atom is investigated studying the response, to various volatile compounds, of six quartz microbalance sensors that are based on the same porphyrin but with different metals. Results show that, since quartz microbalances (QMB) transducers can sense all the interactions between porphyrin and volatile compounds, the metal ion does not completely determine the sensor behaviour. Rather, the sensors based on the same molecular ring but with different metal ions show a non negligible common behaviour. However, even if limited, the different metals still confer peculiar properties to the sensors and might drive the sensor array identification of the pool of tested volatile compounds. © 2016 by the authors; licensee MDPI, Basel, Switzerland

A COMPUTER EMBEDDED CAPACITIVE SENSORS ARRAY

Interdigitate capacitive sensors are promising devices for gas sensing in terms of fabrication costs and ease of integration. The aim of this study was to investigate a novel arrangement of interdigitate capacitors for air quality monitoring with high sensitivity and resolution, using low cost devices at room temperature. The system is fully controlled (through audio device board) by a personal computer which feature represent a great advantage in terms of cost, versatility and ease of use. The paper will describe the characteristics of the interdigitate capacitors, the electronic system and experimental results

Silicon corrole functionalized color catcher strips for fluoride ion detection

Monitoring fluoride ions in drinking water is essential for human health. The ability of (Hydroxy)[5,10,15-tritolylcorrolato]silicon complexes [SiTTC(OH)] to bind fluoride ions with a significant color change is exploited to develop a simple and low-cost device to detect in situ fluoride ions in aqueous media. SiTTC(OH) was deposited on Color Catcher® (CC) strips, representing the first example of this support functionalized with a neutral receptor insoluble in water. The CC-SiTTC(OH) strip preparation protocol was optimized to obtain the best performances. Binding of F−led to a drastic color change in CC-SiTTC (OH), and colorimetric measurements were performed with an inexpensive instrumental setup similar to photo-assisted technique (PT), obtaining a LOD lower than the legal limit of 1.5 mg/L (≈ 80 µM) allowed by WHO. The value of the colorimetric variation, processed in terms of Hue, is able to measure with great accuracy the F−concentration in water samples