1,721,210 research outputs found
Un approccio completo alla rilevazione di gas nocivi
Full text linkIl progetto di ricerca discusso in questa tesi è suddiviso in due line principali:
• la realizzazione di un database sullo stato dell’arte dei sensori di gas;
• lo Sviluppo di prototipi di sensori innovativi per la rilevazione del monossido di carbonio e
del DMMP.
La suddivisione delle attività è mirata a fornire una descrizione completa delle tecniche di
rilevazione di gas nocivi, partendo dall’analisi dello stato dell’arte e dei principi di funzionamento
fino al progetto, realizzazione e test di prototipi basati su tecniche di traduzione innovative.
Lo sviluppo del database, iniziato con la definizione di un modello dell’informazione e proseguito
con la realizzazione dell’architettura, ha portato alla realizzazione di oltre 1000 file che descrivono i
vari aspetti delle più comuni tecniche di traduzione utilizzate nella rilevazione di gas.
La seconda linea di ricerca ha portato allo Sviluppo di prototipi di sensori per la rilevazione di CO e
DMMP.
La scelta del monossido di carbonio come gas target è stata dettata dalla elevata tossicità del
composto e dalla necessità di sviluppare sensori più efficienti rispetto a quelli attualmente presenti
sul mercato.
Lo strato sensibile è stato realizzato con Porfirine di Ferro, di composizione analoga a quelle
presenti nella molecola dell’emoglobina, per utilizzare un meccanismo di interazione simile a
quello che in natura porta ai fenomeni di avvelenamento da CO.
La tecnica di trasduzione scelta è basata su microbilance al quarzo (QMB), per poter rilevare il gas
di interesse attraverso variazioni di massa del dispositivo sensibile.
La qualità dei primi risultati ottenuti ha spinto verso la realizzazione di un dimostratore, punto di
partenza per un futuro Sviluppo a livello di produzione industriale.
Le possibili aree di applicazione di un sensore di questo tipo possono essere individuate in quei
settori in cui è necessario stimare i livelli di esposizione al monossido di carbonio durante le attività
lavorative.
Il secondo composto di interesse è stato scelto in base a due considerazioni fondamentali: in primo
luogo a causa del massiccio impiego a livello industriale, poi per le proprietà chimico-fisiche che lo
rendono simulante del Sarin.
La scelta dello strato sensibile (complessi di ioni lantanidi) è basata su studi preliminari
sull’interazione tra questo tipo di complessi e sostanze chimiche che contengono gruppi P=O.
La tecnica di trasduzione, anche in questo caso a variazione di massa, è stata implementata
utilizzando dispositivi ad onda acustica superficiale (SAW).
I risultati di questo studio sono stati molto incoraggianti, anche se un futuro sviluppo di tipo
commerciale non può prescindere da un maggiore controllo delle condizioni sperimentali.
Infine, è stato condotto uno studio di fattibilità sulla possibilità di realizzare biosensori basati su
aminoacidi e microbalance al quarzo per la rilevazione di monossido di carbonio e DMMP.
La fase sperimentale è stata condotta utilizzando un naso elettronico ed ha dimostrato che questo
tipo di approccio potrà portare in futuro alla realizzazione di sensori dotati di ottime caratteristiche
di sensibilità, selettività e stabilità.
In conclusione, gli obiettivi perseguiti durante il periodo del Corso di Dottorato sono stati raggiunti
con risultati soddisfacenti, tanto che è possible pensare ad un utilizzo a livello industriale sia del
database che dei sensori di gas.
Le attività svolte durante il Corso di Dottorato sono inserite nell’ambito del Progetto di Innovazione
Industriale “Materiali e Tecnologie Innovative per Settori Avanzati”, in collaborazione con il
Centro Sviluppo Materiali S.p.A.The research project discussed within this thesis was split into two main lines:
• realization of a database on the state of the art of gas sensors;
• development of innovative sensors prototypes for carbon monoxide and DMMP detection.
The strategy behind the above separation was to perform a comprehensive approach to dangerous
gases detection, starting from a profound analysis of the state-of-the-art to designing and testing
prototypes to implement new transduction techniques for detecting the analytes with high
sensibility.
Realization of the database required defining the model of information and implementing the
architecture that up to now contains more that 1000 descriptive files concerning the most popular
transduction techniques for gas analysis.
The second activities line was aimed at developing CO and DMMP sensors prototypes.
Carbon Monoxide was selected as a target mainly due to its high toxicity, which claims for better
detecting systems.
The innovative approach to CO sensing was based on a biomimetic technology which uses the high
affinity of iron ions towards CO molecules for enhancing the sensor’s sensitivity and selectivity.
The sensing layers were Fe-porphyrins, analogous the basic compounds of haemoglobin.
Then, the research line intended to use the biological effect of CO poisoning to develop a new kind
of sensor.
The selected transduction technique is based on mass changes, thus using QMB devices for sensing.
The preliminary results where good enough that an industrial demo unit has been realized with the
objective of becoming the starting point for further industrial development.
One of the main application areas of such a device can be envisaged in assessing the exposure to
unknown amounts of CO during work activities.
The second target compound was chosen according to two main considerations: first of all because
of its large industrial use, then because of its chemical properties a simulant of the nerve agent
Sarin.
The composition of the sensitive layers (complexes of lanthanide ions), was chosen as a
consequence of preliminary studies of the interaction mechanisms between lanthanide complexes
and chemical compounds containing a P=O group.
The transduction elements were Surface Acoustic Wave devices (SAW) that allowed implementing
a mass change technique.
Also the results of this study were encouraging enough, even though some additional work on
controlling the environmental parameters and experimental conditions should be done.
Then, great attention was devoted to studying the feasibility of biosensors based on amino acids and
QMB, for detecting CO and DMMP.
These experiments, carried out using an electronic nose, showed that this approach is promising for
obtaining highly sensitive, selective and stable sensors.
Finally, the goals have been reached with satisfactory results and a commercial exploitation of the
prototypes, from the database to the biosensing devices, can be envisaged with a certain degree of
confidence.
The activities developed during this PhD course have been carried out within the frame of the
“Innovative Materials and Technologies for Advanced Sectors” Industrial innovation project, in
cooperation within the Centro Sviluppo Materiali S.p.A
Training in robot-assisted surgery
No full textPurpose of reviewThe aim of this narrative review is to identify the currently available training programs in the field of robotic-assisted surgery.Recent findingsThe lack of well trained robotic surgeons represents the main obstacle facing robotic surgery. This calls for development of structured robotic training programs in order to improve patient safety and outcomes. Structured curriculum should consist of theoretical training (e-learning, case observation), preclinical simulation-based training (virtual reality simulation, dry and wet lab), clinical modular training, and final evaluation. Tele-mentoring might reveal mandatory in future curricula development. To date, several training programs are currently available for robotic surgery. However, the majority lack of clinical modular training that consists of progressive, proficiency-based training through surgical steps with increasing levels of complexity. Moreover, many of these curricula lack validation.SummaryThis recent literature analysis suggests that there is an urgent need to develop and validate new structured training curricula for robotic surgery. This allows to improve the skills of the surgeons and of their team and to prevent patients from being used as a training module optimizing their safety
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A superoxide dismutase biosensor for measuring the antioxidant capacity of blueberry based integrators
Full text linkThe antioxidant capacity of capsules containing blueberry based products which are included among the group of integrators owing to their antioxidant capacity and produced by various films was investigated. The results of the investigation are compared to rank these products in order to their antioxidant capacity. In order to measure antioxidant capacity, our laboratory has recently developed a special electrochemical method based on a superoxide dismutase (SOD) biosensor to determine the superoxide radical. The results obtained by applying the SOD biosensor method to various blueberry based integrators were compared with the results obtained with the spectrophotometric (FRAP) method based on N,N-dimethyl-p-phenylendiamine (DMPD-FeCl3) and with those obtained also using the ORAC fluorimetric (TRAP) method. One of the more interesting aspect of the article is the good agreement it evidences of the results of the three methods for measuring antioxidant capacity. The three methods differ among themselves: an Electron Transfer (ET) method, a Hydrogen Atom Trasnfer Metod (HAT) and an electrochemical based biosensor method of the Morning Superoxide Radical (MSR) type. It is also shown how the antioxidant capacity of the fresh vegetable is in any case always greater then of any food supplement obtained from the same type of vegetable
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