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Diffusion equations and inverse problems regularization.
No full textThe present thesis can be split into two dfferent parts:
The first part mainly deals with the porous and fast diffusion equations.
Chapter 2 presents these equations in the Euclidean setting highlighting the technical issues that arise when trying to extend results in a Riemannian setting. Chapter 3 is devoted to the construction of exhaustion and cut-o_ functions with controlled gradient and Laplacian, on manifolds with Ricci curvature bounded from below by a (possibly unbounded) nonpositive function of the distance from a fixed reference point, and without any assumptions on the topology or the injectivity radius. The cut-offs are then applied to the study of the fast and porous media diffusion, of Lq-properties of the gradient and of the selfadjointness of Schrödinger-type operators.
The second part is concerned with inverse problems regularization applied to image deblurring. In Chapter 5 new variants of the Tikhonov filter method, called fractional and weighted Tikhonov, are presented alongside their saturation properties and converse results on their convergence rates. New iterated fractional Tikhonov regularization methods are then introduced. In Chapter 6 the modified linearized Bregman algorithm is investigated. It is showed that the standard approach based on the block circulant circulant block preconditioner may provide low quality restored images and different preconditioning strategies are then proposed, which improve the quality of the restoration
Tumour Infiltrating (TINK) and Tumour Associated (TANK) Natural Killer cells: role in colorectal cancer (CRC) progression and angiogenesis.
No full textTumor infiltrating immune cells often show a skewed phenotype that reflects attenuation of anti- tumor activity and enhancement of pro-tumor and pro-angiogenic activities. We previously reported that NKs from Non Small Cell Lung Cancer patients are able to acquire the decidual-like CD56+CD16-VEGFhighPlGFhighIL- 8+IFNlow phenotype and promote angiogenesis in vitro. Here, we extended our findings to colorectal cancer (CRC) to verify whether the TINK/TANK polarization may represent a crucial hallmark of solid tumours. We found that CD56+CD16- NK cells predominate in CRC adjacent and tumor tissues, show decreased NKG2D surface expression and impaired cytotoxicity. Further, TINK/TANKs from CRC patients express the decidual NK markers CD9 and CD49a. Secretomic and flow cytometry on CRC peripheral blood NK cells revealed the up-regulation of several pro-angiogenic factors. Molecularly, the STAT-3 and STAT-5 pathway activation was observed in TANKs, suggesting the potential involvement of these signaling pathways in the angiogenic switch. CM by FACS sorted NKs from CRC patients were able to induce HUVEC proliferation, migration, adhesion and the formation of capillary like structures. These functional alterations are related with molecular changes in HUVECs, that include the phosphorylation of AMPKα, GSK-3, P70 S6 Kinase and S6 ribosomal protein. Our data demonstrate that TINK/TANKS from CRC patients are switched toward a proangiogenic/ pro-tumor phenotype and function. We propose that TINK/TANKs could represent a relevant biomarker for CRC progression
Risk assessment in centralized and decentralized online social network.
No full textOne of the main concerns in centralized and decentralized OSNs is related to the fact that OSNs users establish new relationships with unknown people with the result of exposing a huge amount of personal data. This can attract the variety of attackers that try to propagate malwares and malicious items in the network to misuse the personal information of users. Therefore, there have been several research studies to detect specific kinds of attacks by focusing on the topology of the graph [159, 158, 32, 148, 157]. On the other hand, there are several solutions to detect specific kinds of attackers based on the behavior of users. But, most of these approaches either focus on just the topology of the graph [159, 158] or the detection of anomalous users by exploiting supervised learning techniques [157, 47, 86, 125]. However, we have to note that the main issue of supervised learning is that they are not able to detect new attacker's behaviors, since the classifier is trained based on the known behavioral patterns. Literature also offers approaches to detect anomalous users in OSNs that use unsupervised learning approaches [150, 153, 36, 146] or a combination of supervised and unsupervised techniques [153]. But, existing attack defenses are designed to cope with just one specific type of attack. Although several solutions to detect specific kinds of attacks have been recently proposed, there is no general solution to cope with the main privacy/security attacks in OSNs.
In such a scenario, it would be very beneficial to have a solution that can cope with the main privacy/security attacks that can be perpetrated using the social network graph. Our main contribution is proposing a unique unsupervised approach that helps OSNs providers and users to have a global understanding of risky users and detect them. We believe that the core of such a solution is a mechanism able to assign a risk score to each OSNs account. Over the last three years, we have done significant research efforts in analyzing user's behavior to detect risky users included some kinds of well known attacks in centralized and decentralized online social networks.
Our research started by proposing a risk assessment approach based on the idea that the more a user behavior diverges from normal behavior, the more it should be considered risky. In our proposed approach, we monitor and analyze the combination of interaction or activity patterns and friendship patterns of users and build the risk estimation model in order to detect and identify those risky users who follow the behavioral patterns of attackers. Since, users in OSNs follow different behavioral patterns, it is not possible to define a unique standard behavioral model that fits all OSNs users' behaviors. Towards this goal, we propose a two-phase risk assessment approach by grouping users in the first phase to find similar users that share the same behavioral patterns and, then in the second phase, for each identified group, building some normal behavior models and compute for each user the level of divergency from these normal behaviors. Then, we extend this approach for Decentralized Online Social Networks (i.e., DOSNs). In the following of this approach, we propose a solution in defining a risk measure to help users in OSNs to judge their direct contacts so as to avoid friendship with malicious users. Finally, we monitor dynamically the friendship patterns of users in a large social graph over time for any anomalous changes reflecting attacker's behaviors. In this thesis, we will describe all the solutions that we proposed
I limiti delle risorse e le aspettative dei cittadini in sanità: un equilibrio possibile attraverso l'ascolto?
No full textmissin
Gene expression evaluation in patients affected by inflammatory diseases of paranasal sinuses. Valutazione dell’espressione genica in pazienti affetti da patologia infiammatoria dei seni paranasali.
No full textBelow the clinical observation level of chronic rhinosinusitis (CRS) there are several consistent pathophysiological mechanisms different from each other and important in the presentation of the underlying inflammation: so we could say that there are inflammatory endotypes (ET) of CRS.
These ET are subtypes of disease defined functionally and pathologically by a molecular mechanism. Each ET might be identified by specific biomarkers (BM) which originate from the encoding of specific genes.
Analysis of gene expression is the first signal of biologic modifications and leads to the identification of Expression BM.
In our study we compared the expression of selected genes between healthy patients and patients affected by CRS with nasal polyps without hypereosinophilia and/or other comorbidities.
These candidate genes were selected from literature because of their demonstrated hyper/hypo-expression at level of pathological polypoid tissue, sure that replication studies are very important for the progress of science.
In our study for the first time in the same population many genes involved in the pathogenesis of the disease were analysed at the same time and we obtained statistically significant result in 5 genes out of 9 analysed; 4 of these corroborate literature results. These 5 genes are the ones towards which future researches could address further efforts.
Collaboration between ENT and Biologist is essential both for patients endotyping and in elaborating new treatments.
Using well-defined ET in clinical studies might allow to identify patient groups that best benefit from existing as well as new treatments and this could result in personalized multidisciplinary treatments and in a substantial improvement in future patient care
Determination of serum miRNAs biomarkers of lung cancer by quantitative PCR (qPCR) and by droplet digital PCR (ddPCR). Determinazione dei livelli sierici dei miRNA come biomarcatori del cancro al polmone mediante PCR quantitativa (qPCR) e droplet digital PCR (ddPCR).
No full textLung cancer (LC) is often diagnosed at an advanced stage, when it is not radically curable.
Minimally invasive methods allowing identification of asymptomatic subjects with early LC are urgently needed and selected microRNAs (miRNAs) have been suggested as circulating cell-free biomarkers of LC. We compared the performance of two methods, namely qPCR (both absolute and relative) and droplet digital PCR (ddPCR), in accurately measuring the levels of circulating miRNAs of interest for LC. It was found that ddPCR is more precise and provides higher throughput of analysis than standard qPCR, at a similar cost-per-sample; moreover, ddPCR does not rely on external calibrators or reference genes. Following systematic review of the pertinent literature, eight miRNAs of interest for LC were identified and measured by ddPCR in the serum of 85 patients with early LC (stage I and II) and 83 controls. Four miRNAs (let-7a, miR-210, miR-320a, miR-221) showed significantly different serum level in LC patients and in controls. For each of these miRNAs, the Receiver Operating Characteristic curve was constructed and the Area Under the Curve showed fair accuracy in identifying LC cases (about 0.7 for each miRNA). In conclusion, ddPCR was a robust method for absolute quantification of miRNAs of interest for LC. Testing the combination of the above four miRNAs in the serum may help identifying subjects with early LC
‘Primum educere’. L’Obiezione di Coscienza fra gli studenti dei Corsi di Laurea in Ostetricia in Lombardia: studio osservazionale descrittivo trasversale.
No full textThe Italian legislation on abortion and Medically Assisted Procreation (L. 194/78 and L. 40/2004) gives the Healthcare Professionals the opportunity to exercise they right to conscientious objection, a subject of current bioethical debate. From the published literature comes out that students are in an awkward situation and they need to reflect on this issue during the course. The idea of present study emerges from the results of the analyzed literature that underlines how a certain number of medicine students refuses to learn the procedures to provoke the voluntary interruption of pregnancy and claims their right to conscientious objection, more than that, the lack of data referring to midwifery students asserts how necessary a study of this kind can be to help understand their position about the issue.
Objective
The main aim of this study is to try and explore attitudes, legal knowledge, experiences and decision-making possibilities of the students attending the third year of the Bachelor in Midwifery towards conscientious objection in the Universities of Lombardy and the possible need of further education in the field.
Method
This study is an observational study that explore attitudes, legal knowledge and experiences in midwifery student enrolled in five Universities in Lombardy. The sample of the study are the 112 undergraduates of the Bachelor in Midwifery that give their consent to take part in the survey. The enrollment and the data collection happened between September and October 2015. A structured, anonymous questionnaire was used for the survey and it includes 37 closed questions in four sections, and three open questions. It has been distributed to the students by the study team. Of the 112 questionnaires, 111 were returned.
Results
From the study emerges the students have acquired the knowledge of the legislation related the conscientious objection and related laws, with a frequency of 62.9% correct answers.
Analyzing the data comes to light that the students think that the time devoted to teaching conscientious objection and protection of motherhood within the curriculum is not enough and only 51% say that the student has sufficient information on the procedures concerning the conscientious objection. The study shows that the majority of the midwifery students do not know that the law does not mention them among the ones with the right to conscientious objection. On the other hand, the last open answer show that some of them do not know if they have the right to express their attitude during their training. Nevertheless, 88% believe that students have the right to act according to their conscience highlighting their conscientious objection while they are carrying out the study program, even though the sample considers important the achievement of their target training and their claim on moral values, as long as the university recognized a method of achieving that objective which does not require than to perform practices that directly conflict with their own moral values.
The sample was asked if they thought the knowledge of legislation was sufficient to solve ethical position related to situations that could cause conscientious objection: 42 students out of 60 declared to think the knowledge of legislation a necessary but insufficient element to face and solve the answer to conscientious objection.
Conclusion
Even though the students have a global knowledge of the legislation, a deeper and wider general knowledge of the laws in question could be a safeguard both for students and women and more than that it could ensure the provision of the highest standard of care. During the three years of the Bachelor in Midwifery, starting from the first one, more time should be dedicated to the discussion of cases and the analysis of conflicting values. A proposal for the Schools of Medicine could be the creation of a specific form for the conscientious objection, to be filled in by the students who feel the need to make their position official but, first of all, the institution has to create a partnership with its students that guarantees the right of each student to be respected for his own moral values and to be led to an informed, conscious and shared choice over the conscientious objection, via a more adequate training, which can prevent the distress generated when students are not put in the position to be able to face conscientious objection
Document image classification combining textual and visual features.
No full textThis research contributes to the problem of classifying document images. The main addition of this thesis is the exploitation of textual and visual features through an approach that uses Convolutional Neural Networks.
The study uses a combination of Optical Character Recognition and Natural Language Processing algorithms to extract and manipulate relevant text concepts from document images.
Such content information are embedded within document images, with the aim of adding elements which help to improve the classification results of a Convolutional Neural Network.
The experimental phase proves that the overall document classification accuracy of a Convolutional Neural Network trained using these text-augmented document images, is considerably higher than the one achieved by a similar model trained solely on classic document images, especially when different classes of documents share similar visual characteristics. The comparison between our method and state-of-the-art approaches demonstrates the effectiveness of combining visual and textual features.
Although this thesis is about document image classification, the idea of using textual and visual features is not restricted to this context and comes from the observation that textual and visual information are complementary and synergetic in many aspects
