971 research outputs found

    Virtual metrology for semiconductor manufacturing applications

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    Per essere competitive nel mercato, le industrie di semiconduttori devono poter raggiungere elevati standard di produzione a un prezzo ragionevole. Per motivi legati tanto ai costi quanto ai tempi di esecuzione, una strategia di controllo della qualità che preveda la misurazione completa del prodotto non è attuabile; i test sono eettuati su un ristretto campione dei dati originali. Il traguardo del presente lavoro di Tesi è lo studio e l'implementazione, attraverso metodologie di modellistica tipo non lineare, di un algoritmo di metrologia virtuale (Virtual Metrology) d'ausilio al controllo di processo nella produzione di semiconduttori. Infatti, la conoscenza di una stima delle misure non realmente eseguite (misure virtuali) può rappresentare un primo passo verso la costruzione di sistemi di controllo di processo e controllo della qualità sempre più ranati ed ecienti. Da un punto di vista operativo, l'obiettivo è fornire la più accurata stima possibile delle dimensioni critiche a monte della fase di etching, a partire dai dati disponibili (includendo misurazioni da fasi di litograa e deposizione e dati di processo - ove disponibili). Le tecniche statistiche allo stato dell'arte analizzate in questo lavoro comprendono: - multilayer feedforward networks; Confronto e validazione degli algoritmi presi in esame sono stati possibili grazie ai data-set forniti da un'industria manifatturiera di semiconduttori. In conclusione, questo lavoro di Tesi rappresenta un primo passo verso la creazione di un sistema di controllo di processo e controllo della qualità evoluto e essibile, che abbia il ne ultimo di migliorare la qualità della produzione.ope

    Determinazione dei parametri fondamentali di un sistema di ricarica di auto elettriche "While Driving"

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    Determizione dei parametri fondamentali di un sitema di trasferimento wireless, del rendimento e della distanza necessaria per ricaricare la batteria di un'auto elettrica. Per fare questo si è implementato un programma in MatLab che al variare della geometria delle bobine (sorgente e ricevente) e della potenza richiesta dalla batteria, ricava tutti i parametriope

    Magneto-plasmonic nanostructures based on laser ablated nanoparticles of Au and FeOx for nanomedicine applications

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    In the last years, gold and iron oxide nanoparticles have received an increasing interest in nanomedicine and biotechnology thanks to their properties. Gold nanoparticles (AuNPs) are biocompatible and possess useful optical properties that make them a powerful imaging tool using, for example, SERS spectroscopy. On the other hand, iron oxide nanoparticles (FeOxNPs, in particular those made of magnetite) are interesting because of their magnetic properties. Combining gold and iron oxide nanoparticles in a unique system, one obtains a magneto-plasmonic material in which the characteristics properties of the two nanoparticles are present. The use of magneto-plasmonic nanostructured materials in nanomedicine is a quite young research topic and one of the reasons is the elaborated synthesis often required. Several passages are needed also for the purification of these nanosystem from chemicals used during synthesis, which is a crucial point when the final application is in nanomedicine or nanobiology. In this work we will show the synthesis of two magneto-plasmonic systems made of gold and iron oxide nanoparticles. AuNPs and FeOxNPs are synthetized with the laser ablation synthesis in solution (LASiS) method. LASiS is a green chemistry method, which allows to obtain chemical-free and stable nanoparticles in water solution. With LASiS, purification passages are unnecessary or reduced to a minimum and no chemicals that could interfere in biological environment are present. In chapter 2 it will be reported the synthesis of gold and iron oxide nanoclusters (AuFeOxNC) in which the aggregation between particles is performed without the use of chemicals, but exploiting the surface charges of nanoparticles. The use of such nanoclusters in cells guiding and sorting and imaging will be also shown. In chapter 3, the synthesis of another magneto-plasmonic system in which AuNPs and FeOxNPs are arranged in a core-shell-satellite structure, is reported. Also in this case, purification passages are reduced thanks to the laser ablation synthesis. This system is conjugated with an antibody and shows high performance in immunomagnetic sorting and photothermal treatment of cancer cells. The arguments developed in the thesis are introduced in the first chapter

    In silico identification and characterization of a diverse subset of conserved microRNAs in bioenergy crop Arundo donax L.

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    MicroRNAs (miRNAs) are small non-coding RNA molecules involved in the post-transcriptional regulation of gene expression in plants. Arundo donax L. is a perennial C-3 grass considered one of the most promising bioenergy crops. Despite its relevance, many fundamental aspects of its biology still remain to be elucidated. In the present study we carried out the first in silico mining and tissue-specific characterization of microRNAs and their putative targets in A. donax. We identified a total of 141 miRNAs belonging to 14 families along with the corresponding primary miRNAs, precursor miRNAs and a total of 462 high-confidence predicted targets and novel target sites were validated by 5'-race. Gene Ontology functional annotation showed that miRNA targets are constituted mainly by transcription factors, but three of the newly validated targets are enzymes involved in novel functions like RNA editing, acyl lipid metabolism and post-Golgi trafficking. Folding variability of pre-miRNA loops and phylogenetic analyses indicate variable selective pressure acting on the different miRNA families. The set of miRNAs identified in this study will pave the road to further miRNA research in Arundo donax and contribute towards a better understanding of miRNA-mediated gene regulatory processes in other bioenergy crops.Peer reviewe

    Bendamustine plus rituximab is an effective first-line treatment in hairy cell leukemia variant: A report of three cases

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    Hairy cell leukemia variant (HCLv) is a chronic lymphoproliferative disorder classified as a provisional entity in the 2016 WHO Classification of Lymphoid Tumors. HCLv is characterized by unfavorable prognosis, low complete remission rates and limited disease control following classical hairy cell leukemia-based regimens. In this study, we report 3 cases of elderly patients with treatment-naive, TP53 un-mutated HCLv, who were effectively treated with four cycles of bendamustine plus rituximab. The regimen was completed in all the patients with acceptable toxicity. All patients achieved a complete clinical response with no evidence of residual disease at bone marrow biopsy and flow-cytometry examination. After a median follow-up of 19 months, the 3 subjects are still in complete remission. In this work, bendamustine plus rituximab proved to be an effective and feasible first-line treatment strategy for elderly patients with TP53 un-mutated HCLv

    Genetic structure of the Mon-Khmer speaking groups and their affinity to the neighbouring Tai populations in Northern Thailand

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    <p>Abstract</p> <p>Background</p> <p>The Mon-Khmer speaking peoples inhabited northern Thailand before the arrival of the Tai speaking people from southern China in the thirteenth century A.D. Historical and anthropological evidence suggests a close relationship between the Mon-Khmer groups and the present day majority northern Thai groups. In this study, mitochondrial and Y-chromosomal DNA polymorphisms in more than 800 volunteers from eight Mon-Khmer and ten Tai speaking populations were investigated to estimate the degree of genetic divergence between these major linguistic groups and their internal structure.</p> <p>Results</p> <p>A large fraction of genetic variation is observed within populations (about 80% and 90% for mtDNA and the Y-chromosome, respectively). The genetic divergence between populations is much higher in Mon-Khmer than in Tai speaking groups, especially at the paternally inherited markers. The two major linguistic groups are genetically distinct, but only for a marginal fraction (1 to 2%) of the total genetic variation. Genetic distances between populations correlate with their linguistic differences, whereas the geographic distance does not explain the genetic divergence pattern.</p> <p>Conclusions</p> <p>The Mon-Khmer speaking populations in northern Thailand exhibited the genetic divergence among each other and also when compared to Tai speaking peoples. The different drift effects and the post-marital residence patterns between the two linguistic groups are the explanation for a small but significant fraction of the genetic variation pattern within and between them.</p

    The genetic structure and connectivity in two sympatric rodent species with different life histories are similarly affected by land use disturbances

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    The negative impact of habitat fragmentation due to human activities may be different in different species that co-exist in the same area, with consequences on the development of environmental protection plans. Here we aim at understanding the effects produced by different natural and anthropic landscape features on gene flow patterns in two sympatric species with different specializations, one generalist and one specialist, sampled in the same locations. We collected and genotyped 194 wood mice (generalist species) and 199 bank voles (specialist species) from 15 woodlands in a fragmented landscape characterized by different potential barriers to dispersal. Genetic variation and structure were analyzed in the two species, respectively. Effective migration surfaces, isolation-by-resistance (IBR) analysis, and regression with randomization were used to investigate isolation-by-distance (IBD) and the relative importance of land cover elements on gene flow. We observed similar patterns of heterozygosity and IBD for both species, but the bank vole showed higher genetic differences among geographic areas. The IBR analysis suggests that (i) connectivity is reduced in both species by urban areas but more strongly in the specialist bank vole; (ii) cultivated areas act as dispersal corridors in both species; (iii) woodlands appear to be an important factor in increasing connectivity in the bank vole, and less so in the wood mouse. The difference in dispersal abilities between a generalist and specialist species was reflected in the difference in genetic structure, despite extensive habitat changes due to human activities. The negative effects of fragmentation due to the process of urbanization were, at least partially, mitigated by another human product, i.e., cultivated terrains subdivided by hedgerows, and this was true for both species

    Investigating geographic and temporal genetic variation in the black grouse (Lyrurus tetrix) in the Italian Alps

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    The black grouse (Lyrurus tetrix) is a Galliform distributed across northern Eurasia, and is a game bird in most EU countries. Although the species is listed as ‘Least Concern’ by the IUCN, populations at the western and southern edges of its range are considered ‘Vulnerable’ due to increasing habitat fragmentation and human disturbance. Between 1995 and 2017, in collaboration with several hunting associations, we collected more than 600 black grouse samples across seven regions of the Italian Alps. Ten microsatellite markers (STRs) and 2442 Single Nucleotide Polymorphisms (SNPs) were analysed in large subsets of the collected data, with the aim of identifying environmental, temporal and anthropic factors that affect the distribution and level of genomic variation. The main factor shaping the genetic distances between populations based on STRs is the geographic distance between them (i.e. isolation-bydistance), but even the populations on the two extremes of our sampling area are very similar (Fst between the two regions = 0.053). SNP data supports the STR analysis. However, isolation-by-resistance methods for the larger STR data set show that both higher altitudes and urban areas inhibit movement of grouse between populations. While temporal analysis of STRs for the Trentino-Alto Adige region showed no significant change in the mean number of alleles and allelic size range between the two time frames studied (e.g. mean number of alleles 1995-1999: 8.8, 2009-2010: 8.2), and the expected heterozygosity was high in both time frames (1995-1999: 0.740, 2009-2010: 0.722). While black grouse population size is reportedly decreasing, our results suggest there is no measurable genetic impact from this trend. Hence this dataset provides a basis for future monitoring of genetic diversity in this charismatic alpine species

    The predictive and prognostic potential of plasma telomerase reverse transcriptase (TERT) RNA in rectal cancer patients

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    Background: Preoperative chemoradiotherapy (CRT) followed by surgery is the standard care for locally advanced rectal cancer, but tumour response to CRT and disease outcome are variable. The current study aimed to investigate the effectiveness of plasma telomerase reverse transcriptase (TERT) levels in predicting tumour response and clinical outcome. Methods: 176 rectal cancer patients were included. Plasma samples were collected at baseline (before CRT\ubcT0), 2 weeks after CRT was initiated (T1), post-CRT and before surgery (T2), and 4\u20138 months after surgery (T3) time points. Plasma TERT mRNA levels and total cell-free RNA were determined using real-time PCR. Results: Plasma levels of TERT were significantly lower at T2 (Po0.0001) in responders than in non-responders. Post-CRT TERT levels and the differences between pre- and post-CRT TERT levels independently predicted tumour response, and the prediction model had an area under curve of 0.80 (95% confidence interval (CI) 0.73\u20130.87). Multiple analysis demonstrated that patients with detectable TERT levels at T2 and T3 time points had a risk of disease progression 2.13 (95% CI 1.10\u20134.11)-fold and 4.55 (95% CI 1.48\u201313.95)-fold higher, respectively, than those with undetectable plasma TERT levels. Conclusions: Plasma TERT levels are independent markers of tumour response and are prognostic of disease progression in rectal cancer patients who undergo neoadjuvant therapy
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