15 research outputs found
Molecular epidemiology of Listeria monocytogenes: genotyping, molecular serotyping and expression profiles analysis of genes involved in pathogenesis and virulence mechanisms
No full textListeria monocytogenes è un patogeno intracellulare responsabile di severe infezioni caratterizzate da un elevato tasso di letalità, soprattutto in soggetti con deficit del sistema immunitario. Data la diffusa presenza e l’estrema variabilità nella virulenza dei ceppi, molteplici tecniche molecolari sono utilizzate per individuare le differenze esistenti all’interno della specie. In questo studio, 250 ceppi di L. monocytogenes di differente origine sono stati caratterizzati mediante single Enzyme Amplified Fragment Length Polymorphism (sAFLP). Un sottogruppo rappresentativo di 50 ceppi è stato selezionato per confrontare l’elettroforesi su gel di agarosio, prevista dalla metodica, con la separazione microfluidica automatizzata (sistema ExperionTM) su chip. Inoltre, altri 109 ceppi di Listeria spp. sono stati analizzati per standardizzare un nuovo saggio in Real-time, basato su due Triplex-PCR con sonde TaqMan, per l’individuazione dei sierogruppi i cui risultati sono stati confrontati con il metodo molecolare di riferimento. Infine, è stata valutata, mediante qRT-PCR, l’espressione di geni di resistenza a stress e dei principali fattori di virulenza in 20 isolati da alimenti e casi clinici. In particolare, è stato valutato l’effetto di concentrazioni sub-letali (10 ppm) di cloruro di benzalconio sull’espressione di sigB (fattore sigma alternativo di risposta a stress), mdrL e lde (pompe di efflusso) e orfA (ipotetico repressore di mdrL). In parallelo, è stata valutata l’attività antibatterica del disinfettante secondo la UNI EN 1276/2000. Per gli stessi isolati sono stati anche determinati i livelli di espressione dei geni codificanti le internaline A e B (inlA, inlB), la listeriolisina O (hly), il regolatore trascrizionale (prfA) di LIPI-1 e l’idrolasi dei sali biliari (bsh). La genotipizzazione mediante sAFLP ha permesso di identificare 13 clusters, rappresentativi di due gruppi principali distinti e concordanti con la classificazione in Lineage e con i dati epidemiologici di prevalenza dei sierotipi responsabili di infezioni umane e della contaminazione di alimenti. La sAFLP si è rivelata una metodica accurata e altamente discriminante per la genotipizzazione del patogeno, anche in combinazione con l’elettroforesi microfluidica, la quale ha fornito risultati analoghi al metodo tradizionale con una migliore risoluzione nella visualizzazione delle bande. Il sistema ExperionTM richiede quantità inferiori di campione, evita l’impiego di reagenti tossici e riduce sensibilmente i tempi di analisi, rappresentando un valido supporto per la caratterizzazione del patogeno mediante sAFLP. La sierotipizzazione molecolare in Real-time PCR ha confermato la precedente classificazione in sierogruppi, permettendo la separazione dei sierotipi 1/2a, 1/2b, 1/2c e 4b, implicati in oltre il 90% di casi umani e di contaminazione di alimenti, in quattro gruppi distinti. Il metodo proposto risulta accurato e riproducibile e può contribuire all’implementazione delle misure di sorveglianza epidemiologica per il controllo della listeriosi. Il cloruro di benzalconio è risultato efficace nel 70% dei ceppi analizzati, soprattutto negli isolati umani e ha influenzato l’espressione dei geni target. Differenze significative (p<0,05) sono state osservate nei livelli di trascrizione di mdrL e sigB in seguito al trattamento con disinfettante. In tutti gli isolati da alimenti risultati resistenti, sono emersi livelli di espressione più elevati di sigB, mdrL e lde. L’attivazione di sistemi di efflusso può portare ad un aumento della resistenza dei ceppi non solo verso il cloruro di benzalconio, ma anche contribuire allo sviluppo di fenomeni di resistenza crociata con antibiotici. Maggiori livelli di espressione di inlB, hly, prfA e bsh sono stati osservati nei ceppi umani, al contrario di quelli di inlA più elevati negli isolati da alimenti. Tuttavia, i valori massimi di inlA hanno riguardato due ceppi clinici, in cui sono emersi livelli di espressione elevati per tutti i geni target, facendone ipotizzare un maggiore potenziale di virulenza. Una correlazione molto significativa è stata osservata tra i livelli di espressione di inlA e inlB e in misura minore tra prfA e bsh, in accordo con i dati di letteratura. Dall’analisi delle curve di melting sono emerse differenze significative (≤0,001) tra gli isolati della Lineage I (1/2b, 4b) rispetto alla II (1/2a, 3a, 1/2c) per i geni mdrL, lde, inlA, prfA, bsh, suggerendo una probabile diversità di sequenza. La comprensione dei meccanismi molecolari e la caratterizzazione dei ceppi potenzialmente più virulenti sono aspetti fondamentali per il controllo della listeriosi, in quanto consentono di migliorare la sorveglianza e la prevenzione del rischio associato a L. monocytogenes per la salute umana.Listeria monocytogenes is a intracellular bacterium widely distributed in the environment that causes severe diseases with a high fatality rate especially in immunocompromised individuals.
Several molecular techniques have been developed for strains characterization because significant differences in the virulence profile of isolates have been demonstrated.
In this study, L. monocytogenes strains (n=250) from different sources were analysed by single Enzyme Amplified Fragment Length Polymorphism (sAFLP). A representative subgroup was selected to compare the traditional gel electrophoresis with a chip-based microfluidic system (ExperionTM). Moreover, additional Listeria spp. isolates (n=109) were selected to standardize a new assay for serogroup identification in Real-time by using two different TaqMan-based Triplex-PCR and the results were compared with molecular reference method. Furthermore, by qRT-PCR, the expression levels of stress response and virulence genes were evaluated in isolates (n=20) from foods and human listeriosis. Particularly, the effects of sub-lethal concentration of benzalkonium chloride (10 ppm) on the expression profiles of sigB (stress-response sigma factor), mdrL and lde (efflux pumps), and orfA (putative mdrL repressor) were assessed. The antimicrobial activity of benzalkonium chloride (BC) was also investigated according to UNI EN 1276/2000. Finally, the expression levels of genes encoding the internalins A and B (inlA, inlB), Listeriolysin O (hly), the LIPI-1 transcriptional regulator (prfA), and bile salt hydrolase (bsh) were determined.
Genotyping by sAFLP allowed to identify 13 clusters, included in two well defined groups and in agreement to the Lineage classification and epidemiological data on the prevalence of most common serotypes involved in human illness and foodstuffs contamination. The sAFLP has proved to be an accurate method with high discriminatory power for L. monocytogenes typing and its epidemiological usefulness was further confirmed in combination with automated microfluidic electrophoresis system, requiring lower samples volume and time analysis.
Molecular serogrouping by Real-time PCR confirmed previous classification into four groups and allowed a rapid discrimination of 1/2a, 1/2b, 1/2c, and 4b serotypes, recognized in more than 90% of food and patients isolates. Therefore, the new approach can improve routine surveillance of listeriosis and epidemiological investigations. The benzalkonium chloride showed the antimicrobial activity in 70% of strains, particularly in human isolates and affected the target genes expression. Adaptation to BC determined a significant (p<0,05) overexpression of mdrl and sigB. All less sensitive food isolates showed the highest sigB, mdrL, and lde transcription levels. The efflux pumps could play a role in BC-resistance and the sub-lethal exposure to antimicrobial agent can lead cross-resistance between antibiotics and disinfectants.
The expression levels of inlB, hly, prfA and bsh were higher in clinical than in food strains, except for inlA. However, the maximum levels of inlA were found in two human strains which also showed high levels of all virulence genes. A significant correlation between inlA and inlB expression was observed as between prfA and bsh, according to other studies. Furthermore, relevant differences (≤0,001) between Lineage I (1/2b, 4b) and II (1/2a, 3a, 1/2c) strains were found in mdrL, lde, inlA, prfA, and bsh melting temperature, suggesting the presence of mutations in genomic sequence. The characterization of more virulent strains and the comprehension of molecular mechanisms are essential for the epidemiological surveillance and the risk assessment of human listeriosis.Dottorato di ricerca in Scienze per la salute (XXIV ciclo
Amplified fragment lenght polymorphism analysis of Listeria monocytogenes by experionTM automated microfluidic electrophoresis
No full textFifty Listeria monocytogenes strains were genotyped by sAFLP and PCR products were separated by agarose gel and automated chip-based microfluidic electrophoresis. A high congruency of results was observed comparing the two techniques, although for some cultures a better separation of sAFLP fragments was achieved with microfluidic system, which proved to be a highly reliable and reproducible tool to improve the molecular typing of L. monocytogenes, requiring lower volumes of samples and reducing significantly analysis time
System-on-chip Computing and Interconnection Architectures for Telecommunications and Signal Processing
No full textThis dissertation proposes novel architectures and design techniques targeting SoC building blocks for telecommunications and signal processing applications.
Hardware implementation of Low-Density Parity-Check decoders is approached at both the algorithmic and the architecture level. Low-Density Parity-Check codes are a promising coding scheme for future communication standards due to their outstanding error correction performance.
This work proposes a methodology for analyzing effects of finite precision arithmetic on error correction performance and hardware complexity. The methodology is throughout employed for co-designing the decoder. First, a low-complexity check node based on the P-output decoding principle is designed and characterized on a CMOS standard-cells library. Results demonstrate implementation loss below 0.2 dB down to BER of 10^{-8} and a saving in complexity up to 59% with respect to other works in recent literature. High-throughput and low-latency issues are addressed with modified single-phase decoding schedules. A new "memory-aware" schedule is proposed requiring down to 20% of memory with respect to the traditional two-phase flooding decoding. Additionally, throughput is doubled and logic complexity reduced of 12%. These advantages are traded-off with error correction performance, thus making the solution attractive only for long codes, as those adopted in the DVB-S2 standard. The "layered decoding" principle is extended to those codes not specifically conceived for this technique. Proposed architectures exhibit complexity savings in the order of 40% for both area and power consumption figures, while implementation loss is smaller than 0.05 dB.
Most modern communication standards employ Orthogonal Frequency Division Multiplexing as part of their physical layer. The core of OFDM is the Fast Fourier Transform and its inverse in charge of symbols (de)modulation. Requirements on throughput and energy efficiency call for FFT hardware implementation, while ubiquity of FFT suggests the design of parametric, re-configurable and re-usable IP hardware macrocells. In this context, this thesis describes an FFT/IFFT core compiler particularly suited for implementation of OFDM communication systems. The tool employs an accuracy-driven configuration engine which automatically profiles the internal arithmetic and generates a core with minimum operands bit-width and thus minimum circuit complexity. The engine performs a closed-loop optimization over three different internal arithmetic models (fixed-point, block floating-point and convergent block floating-point) using the numerical accuracy budget given by the user as a reference point. The flexibility and re-usability of the proposed macrocell are illustrated through several case studies which encompass all current state-of-the-art OFDM communications standards (WLAN, WMAN, xDSL, DVB-T/H, DAB and UWB). Implementations results are presented for two deep sub-micron standard-cells libraries (65 and 90 nm) and commercially available FPGA devices. Compared with other FFT core compilers, the proposed environment produces macrocells with lower circuit complexity and same system level performance (throughput, transform size and numerical accuracy).
The final part of this dissertation focuses on the Network-on-Chip design paradigm whose goal is building scalable communication infrastructures connecting hundreds of core. A low-complexity link architecture for mesochronous on-chip communication is discussed. The link enables skew constraint looseness in the clock tree synthesis, frequency speed-up, power consumption reduction and faster back-end turnarounds. The proposed architecture reaches a maximum clock frequency of 1 GHz on 65 nm low-leakage CMOS standard-cells library. In a complex test case with a full-blown NoC infrastructure, the link overhead is only 3% of chip area and 0.5% of leakage power consumption.
Finally, a new methodology, named metacoding, is proposed. Metacoding generates correct-by-construction technology independent RTL codebases for NoC building blocks. The RTL coding phase is abstracted and modeled with an Object Oriented framework, integrated within a commercial tool for IP packaging (Synopsys CoreTools suite). Compared with traditional coding styles based on pre-processor directives, metacoding produces 65% smaller codebases and reduces the configurations to verify up to three orders of magnitude
Growing Connection, Creativity, and Community at the Clark Park Community Garden in Tempe, AZ
No full textabstract: Working in collaboration with the Clark Park Community Garden (CPCG), we sought to identify and implement practices and creative processes that increase community involvement and connection by further transforming the space into a community gathering place. Our primary goal was to foster greater community involvement within the garden through various methods while exploring our own creative outlets to represent what the concepts of “community” and “garden” mean to us.
When initially planning our project, we outlined a research process to conduct interviews with garden participants to determine the best practices for community garden connection-making. However, after our initial discussions with the CPCG Advisory Committee, it became clear that their goals could be better achieved through an applied project focusing on increasing community connection than from a research project. We have adopted our former research question--which asked how community gardens could serve as a means for community connection-- as our premise, and we seek to build upon it through the creation of programs, partnerships, and pieces of art that collectively expand the garden’s connection to its surrounding community. To begin this process, we worked with the leaders of the CPCG to identify the group’s main goals that they sought to achieve with our support. In collaboration with the CPCG Garden Advisory Committee, the three goals that we identified were: 1) increasing neighborhood participation in the space, 2) launching the site’s new subscription program, and 3) transforming the garden space into a place of community
Il Libro dei Miracoli: Intersections of Gender, Class and Portraiture in Italian Multimedia Votive Sculpture, 1450-1630
No full textabstract: Multi-media votive sculpture, made from wax, papier-mâché, wood, terra cotta and textiles, is a long-neglected subject of study in early modern Italian art history. This dissertation focuses on an unparalleled seventeenth-century manuscript, the Libro dei miracoli, which reproduces in watercolor a number of the lost multi-media votive statues that once populated the church of S. Maria della Quercia in Viterbo. The names of votaries, along with a description of their miracles, accompany the watercolors and present an invaluable source of information that allows for this first comprehensive study of votary identity. Abundant archival material maintained by S. Maria della Quercia, situated within larger historical events and cultural trends, informs this dissertation which explores the democratic nature behind votive statuary effigies. The offerings granted male and female members of most socio-economic classes in early modern Italy the extraordinary opportunity to act as patrons of art. Moreover, the sculptures, and watercolors after them, were individualized representations of votaries that can be considered a form of portraiture available to rich and poor alike.Dissertation/ThesisPh.D. Art History 201
The Art of Inventing Matilda of Canossa
No full textabstract: Matilda of Canossa (1046 to 1115), the Great Countess of Tuscany, was a noblewoman, a warrior, and a papal supporter who later generations adapted to satisfy a variety of cultural and ideological interests. Matilda's life as a ruler was amplified over the following five hundred years in an avalanche of words and images that served many purposes. This thesis considers the art produced during her lifetime in the context of disputes over papal authority, as well as art produced about Matilda subsequently. The study includes a discussion of her appearance in Dante's Comedy; her importance to Florentine artists such as Sandro Botticelli, Leonardo da Vinci, and Michelangelo Buonarroti in the 16th century; and concludes with the significance of the elaborate tomb sculpted for her reburial by Gian Lorenzo Bernini in St. Peter's Cathedral. An examination of Matilda through these shifting representations from the 12th to the 17th century enables an understanding of how and why she became an impressive symbol in the visual arts. Finally, the study examines the process through which a strong, powerful woman was transformed from an historical person to a legend. Matilda's remarkable life and myth is still relevant to art historical, religious and cultural studies because of the pervasiveness of her influence a millennium after her death.Dissertation/ThesisM.A. Art History 201
A Look into the Mediterranean Diet and How it Can Lead to Personal, Social, and Environmental Benefits
No full textabstract: Peasant communities on the Italian Peninsula relied on local climate and geography to produce fruits, vegetables, and grains. Over centuries, these peasant communities developed a system of food practices which became part of an integrative lifestyle people on the Italian Peninsula are still engaged in today. Through social and familial traditions that passed down through generations, these food practices were coined in the 20th century as the “Mediterranean Diet”. “Diet” in this context is defined by using the etymology of the Greek word ‘diaita’, which means “way of life”. The Mediterranean Diet represents a relationship with food, communities, and environments that promote health in several spaces. From peasant roots, the Mediterranean diet encourages the consumption of whole ingredients from fruits, vegetables, grains, and fish, with little emphasis on meats, poultries, and processed sugars, while also preparing and eating those foods with others. In the 21st century, these traditional food practices represent Personal, Social, and Environmental benefits which occur naturally from plant-based diets and socially minded eating practices. This thesis and creative project discusses the history, culture, science, and relevance of the traditional food practices of the Italian Peninsula and how it can be applied to one’s life. This is accomplished through a synthesis of comprehensive research related to the history and science of the Mediterranean Diet and its relationship to the body, society, and the environment, and engages the reader utilizing creative elements. This thesis encourages the reader to ask and answer the following questions: What does the food we eat mean in our lives? How does the food we eat reflect our values? How does our relationship with food affect our relationships with others? And how does the food we eat affect the world around us
Conceiving the Mediterranean Diet as a Dynamic System of Relationships
No full textabstract: The concept of the Mediterranean Diet was described by Ancel Keys from the Seven Countries study, occurring in the 1960s. Unlike other diets, the Mediterranean Diet is a cultural tradition of nations surrounding the Mediterranean Sea. It involves the healthy pattern of food consumption and physical activity, which developed as an outcome of the locality's available food, other environmental resources, and overall cultural characteristics such as the polychromic time orientation of the Mediterranean nations. The Mediterranean Diet is a lifestyle structured around understanding a locality's natural conditions and resources and sustaining positive relationships between individuals, the community, and the components of their environment. The diet is largely plant based, where daily foods include grains, fruits, vegetables, olive oil, and dairy products. Seafood is eaten several times a week, while other animal products (poultry, meats, eggs) and sweets are eaten less often and in moderation. Alcohol, for those who drink it, is consumed several times a week. Research has shown a variety of health benefits from this diet. These benefits include preventing cardiovascular disease, certain cancers, Type 2 diabetes, Alzheimer's disease, age related macular degeneration of the eyes, kidney disease and osteoporosis. It also has been shown to improve conditions of metabolic syndrome, obesity, and depression. These favorable health outcomes are a result of the beneficial components within the foods commonly eaten. Fruits and vegetables are excellent sources of vitamins and minerals, which are needed to support cellular and overall organismal functioning, and nuts, vegetables, and fish also provide essential fatty acids like omega-3 and omega-6. The unifying component for all regions adhering to the Mediterranean Diet is the use of olive oil. Beyond being a healthy source of fat, it contains numerous chemical components with antioxidant properties. The Mediterranean region is an optimal region for olive tree growth and olive harvest, based on temperature and soil conditions. However, geographic differences, nutrient availability and age of olive trees can impact the quality of olive fruits and olive oil. Furthermore, climate change presents a challenge for sustaining the Mediterranean diet as it adds stress to plants and aquatic life environments. However, the diet shows promise of protecting the environment, as plant-based diets are found to have lower negative environmental impacts. In conclusion, the Mediterranean diet is an interconnected system of relationships that adapts to a locality's community, land, and climate
Victor and Vanquished: An Examination of Divergent Post-WWII Film Movements in Germany, Italy, and the United States
No full textabstract: History and art have always had an intersecting relationship, and each helps us to acquire a better understanding of the other, since artistic works help us to visualize the zeitgeist of a particular point in history. The connection between art and history is most apparent when the radical changes that befall society through historically important events, especially conflict, are followed by sweeping changes in society, which trickle their way down into the minds of artists and creators, whose works subsequently reflect these changes. We cannot understand these works and their relationship to their respective period of time simply by isolating them into individual components like art style, artist, and location. They are socially and historically charged, part of a larger network of intersecting relationships that factor in concepts like ideology, material, and culture. We can examine the analytical power of this framework, better known as actor network theory, in a post-WWII European landscape, a period heightened by rapid social changes as the citizens of the formerly war-torn continent worked to rebuild and recover. When examining the artistic output of vanquished nations, mainly Italian neorealist films and German Trümmerfilmen, in a framework built around the principles established in actor network theory, we can see how the historical, political, social, and cultural developments established in the wake of European fascism’s unceremonious collapse is reflected on film when compared to the victorious United States, whose infrastructure and film industry remained mostly unscathed
Ficciones de una guerra. La guerra de Malvinas en la literatura y el cine Argentinos
No full textI examine a corpus of literary and audiovisual narratives, in both fictional and documentary forms, that revolve around the 1982 war between Argentina and Great Britain for sovereignty over the Malvinas/Falkland Islands. My analysis takes into account, among others, texts by Rodolfo Fogwill, Carlos Gamerro, Jorge Stamadianos, Mart??n Kohan, Rodrigo Fres??n, Osvaldo Lamborghini, and Jorge Luis Borges, and films such as Trist??n Bauer's Blessed By Fire and Jos?? Luis Marqu??s' Fuckland.
Most of the fictions produced over the last twenty-five years have been successful in eluding the nationalist prerogatives and the idea of the just cause that permeate political discourses, testimonies or historical essays, and have managed to pose complex responses to the questions of the war's aftermath. I examine the conflict of the Falklands utilizing Michel Foucault's idea of biopower and Giorgio Agamben's contributions and reformulations on this subject. I also analyze it in the context of Karl Von Clausewitz's theory of war and the most recent attempts to reconsider the role of war on the global map of international relations by Paul Virilio, Michael Hardt and Toni Negri.
The fictions of Malvinas/Falklands propose the impossibility of narrating an epic of this conflict by telling stories of survival, mocking the nationalist prerogatives and dismantling the very idea of national identity. At the same time, these fictions are pervaded by the weight of the father-State law and they represent a predominantly masculine universe. Epic is the world of the elderly, the ancestors, the fathers, and many of the fictions analyzed here turn to narratives of impossible or problematic paternities. I argue that by questioning the father-State law, these fictions question the validity of the epic narrative as well.
As an epilog, this work also includes a travel chronicle of the researcher to the origin of her object of study. In this journey, the fictional space, created from imagination, is confronted with a personal, intimate narrative, in the physical space of the Falkland Islands.Ph.D.Includes bibliographical references (p. 188-192)
