Progetto, realizzazione e validazione sperimentale di un'applicazione SDN per Traffic Recovery e Load Balancing

Nel corso degli ultimi anni, la comunità scientifica si è prodigata nell'esplorazione delle potenzialità fornite dal Software-Defined Networking, un paradigma che prevede la netta separazione tra piano dati e piano di controllo all'interno di una rete. Così facendo, il comportamento dei dispositivi risulta programmabile tramite un'applicazione di controllo. In questo contesto, il presente elaborato documenta il lavoro di tesi intrapreso per progettare, realizzare e validare una tale applicazione avente funzionalità di Traffic Recovery e Load Balancing. Le stime riguardanti l'utilizzazione dei collegamenti e la banda occupata dai vari flussi, così come la rivelazione dei malfunzionamenti, sono state gestite sfruttando le peculiarità del protocollo OpenFlow. L'aspetto relativo alla Traffic Recovery è stato affrontato con strategie sia reattive che proattive. In particolare, il traffico generato dalle sorgenti può essere suddiviso in quattro classi, caratterizzate da un livello di protezione via via crescente. Riguardo alla funzionalità di Load Balancing, sono state adottate e confontate tre possibili metriche per l'assegnazione dei costi ai vari collegamenti, in funzione del carico da essi sperimentato. During the last years, Software-Defined Networking (SDN) has been widely explored in order to understand the possibilities provided by this kind of architecture. Introducing a clean separation between the control plane and the data plane within the network, SDN allows a control application to program the behavior of the underlying infrastructure. This thesis deals with designing, fulfilling and validating such an application with Traffic Recovery and Load Balancing tasks. The features of the OpenFlow protocol have been exploited in order to provide an estimate of links utilization and flows bandwidth, as well as to effectively detect link failures. Traffic Recovery has been handled adopting both reactive and proactive strategies. More precisely, network traffic can be grouped into four classes with an increasing level of protection. With respect to Load Balancing, three alternative ways of assigning a cost to a certain link, as a function of its load, have been defined and compared

Class-based traffic recovery with load balancing in software-defined networks

In the last years, Software-Defined Networking (SDN) has emerged as a flexible paradigm driving innovation in future network architectures. Unfortunately, resilience, a key requirement in IP networks, is not an inherent feature of the SDN architecture. Indeed, the automatic reconfigurability of traffic paths in case of links or nodes failures is no more available. This paper deals with the design and validation of an SDN control application for class-based traffic recovery with load balancing. The features of the OpenFlow protocol have been exploited to timely detect link failures as well as to estimate links utilization. The performance of different strategies for class-based traffic recovery has been evaluated in an emulated environment, based on the widely used Mininet tool, highlighting the effectiveness of the proposed solution in enterprise networks

A New Surgical Device for Anterograde Intraoperative Rectal Washout

Background. Colorectal cancer is the fourth most diffuse cause of death in the world and local recurrence is associated with a reduced long-term life expectancy, with a reduced quality of life. Rectal washout at the anastomosis site leads to a statistically significant reduction of local recurrences. Methods. We developed the idea of a new laparoscopic stapler with an integrated washout system that could decontaminate the rectal stump before resection, without the need to enlarge the standard surgical incision or even to distort the incision site, closing the rectal stump just below the inferior part of the cancer, and then proceeding with the resection and stapling of the distal part of the tumor. Combined with these canonical functionalities, the new device, equipped with a patented washout system (patent number EP 3103401A1) will also allow to inject in the closed bowel a physiologic saline liquid. Results. In force of the mechanical action of the liquid injected, carcinogenic exfoliated cells eventually floating in the affected region of the colonic lumen will be expelled through the anal orifice. The intraoperative rectal washout, both in minimally invasive and in traditional open surgery, thus becomes a simple, effective, and reproducible procedure. Conclusions. We describe the technical features and the possible clinical applications of a potentially new surgical laparoscopic stapler coupled with an integrated irrigation system. We have patented the system and we are developing a prototype with the aim to start an experimental pilot study

Pathological examination of breast cancer samples before and after neoadjuvant therapy: recommendations from the Italian Group for the Study of Breast Pathology - Italian Society of Pathology (GIPaM-SIAPeC)

Neoadjuvant therapy (NAT) in breast cancer is administered to downstage the tumor, deescalate surgery, and provide prognostic information that can be used to tailor subsequent adjuvant therapy. In this respect, the pathological evaluation of both pre-NAT biopsies and post-NAT surgical specimens is crucial to precisely assess the treatment response. With the increasing possibilities of NAT protocols and the rising number of eligible patients, it has become extremely important to standardize the pathological response assessment. Here, we provide an update on the recommendations of the Italian Group for the Study of Breast Pathology - the Italian Society of Pathology (GIPaM-SIAPeC) for the analysis of breast cancer samples before and after NAT

Paclitaxel and Bevacizumab in First Line-Treatment Patients with HER-2 Negative Advanced Breast Cancer: Who could Benefit?

Background: Angiogenesis is essential for tumor growth and development of metastases in human breast cancer. Randomized studies have shown that bevacizumab (inhibitor of VEGF) combined with taxane-based regimens increases response rates and prolongs Progression-Free Survival (PFS) of patients with Metastatic Breast Cancer (MBC). However predictive or prognostic markers that identify the appropriate target population, thus improving the cost-effectiveness ratio of this treatment, are still needed. In this retrospective analysis, we investigated the impact of traditional clinical and pathological features in order to identify the subgroups of patients who derive the greatest benefit from antiangiogenic-agents. Patients and methods: Retrospectively, we included consecutive patients treated with bevacizumab (10 mg/Kg on days 1 and 15) and paclitaxel (90 mg/m2, on days 1, 8 and 15) as first-line treatment for HER2-negative MBC at our Institution between June 2007 and December 2012. Results: 33 patients were included. Median age was 50 years (31-68). 78. 8%, 12.1% and 9.1% of patients had luminal B, triple negative and luminal A breast cancer, respectively. 66. 6% of patients had visceral disease. The overall response rate was 31.2%. Median PFS and overall survival (OS) were 7.7 months (range 1. 9-14.0 months) and 95.2 months (range 11.6-205.8 months), respectively. Univariate analysis highlighted a statistically significant relationship between PFS to the first line and the following factors: relapse-free survival (RFS12 months; p<0,001), disease control rate (p=0,001), Ca15. 3 reduction of more than 50% from baseline (p=0,03), reduction of LDH from baseline (p=0,02). No significant relationship resulted between PFS and the biological characterization of neoplasia, age, receptor status, Ki-67, nodal status at diagnosis, having carried out a previous (neo) adjuvant chemotherapy (with or without taxane), having visceral disease at time of relapse, the histological evidence of lymph-vascular invasion. At multivariate analysis, RFS was the only confirmed independent prognostic factor (p=0.01; HR=0. 18; 95% CI 0. 04-0.73). Conclusion: Our results confirmed the efficacy and the acceptable toxicity profile of bevacizumab plus paclitaxel as first-line regimen for MBC. RFS may be a useful tool in the clinical practice to select HER-2 negative MBC which may obtain a better prognosis administering this particular regimen

Androgen Receptor Expression in Early Triple-Negative Breast Cancer: Clinical Significance and Prognostic Associations

Background: Triple-negative breast cancers (TNBC) are characterized by aggressive tumour biology resulting in a poor prognosis. Androgen receptor (AR) is one of newly emerging biomarker in TNBC. In recent years, ARs have been demonstrated to play an important role in the genesis and in the development of breast cancer, although their prognostic role is still debated. In the present study, we explored the correlation of AR expression with clinical, pathological and molecular features and its impact on prognosis in early TNBC. Patients and Methods: ARs were considered positive in case of tumors with &gt;10% nuclear-stained. Survival distribution was estimated by the Kaplan Meier method. The univariate and multivariate analyses were performed. The difference among variables were calculated by chi-square test. Results: 81 TNBC patients diagnosed between January 2006 and December 2011 were included in the analysis. Slides were stained immunohistochemically for estrogen and progesterone receptors, HER-2, Ki-67, ALDH1, e-cadherin and AR. Of the 81 TNBC samples, 18.8% showed positive immunostaining for AR, 23.5% and 44.4% of patients were negative for e-cadherin and ALDH1, respectively. Positive AR immunostaining was inversely correlated with a higher Ki-67 (p &lt; 0.0001) and a lympho-vascular invasion (p = 0.01), but no other variables. Univariate survival analysis revealed that AR expression was not associated with disease-free survival (p = 0.72) or overall survival (p = 0.93). Conclusions: The expression of AR is associated with some biological features of TNBC, such as Ki-67 and lympho-vascular invasion; nevertheless the prognostic significance of AR was not documented in our analysis. However, since ARs are expressed in a significant number of TNBC, prospective studies in order to determine the biological mechanisms and their potential role as novel treatment target

Pre-treatment neutrophil to lymphocyte ratio may be a useful tool in predicting survival in early triple negative breast cancer patients

BACKGROUND: There is a growing body of evidence that immune response plays a large role in cancer outcome. The neutrophil to lymphocyte ratio (NLR) has been used as a simple parameter of systemic inflammation in several tumors. The purpose was to investigate the association between pre-treatment NLR, disease-free survival and overall survival in patients with early triple negative breast cancer (TNBC). METHODS: We reviewed the records of patients with stage I-III TNBC at our Institution from 2006 to 2012. The association between pre-treatment NLR and survival was analyzed. The difference among variables was calculated by chi-square test. DFS and OS were estimated using Kaplan-Meier method. Cox analysis was performed to analyze clinical parameters for their prognostic relevance. RESULTS: A total of 90 patients were eligible. There was no significant correlation among pre-treatment NLR and various clinical pathological factors. Patients with NLR higher than 3 showed significantly lower DFS (p = 0.002) and OS (p = 0.009) than patients with NLR equal or lower than 3. The Cox proportional multivariate hazard model revealed that higher pre-treatment NLR was independently correlated with poor DFS and OS, with hazard ratio 5.15 (95% confidence interval [CI] 1.11-23.88, p = 0.03) and 6.16 (95% CI 1.54-24.66, p = 0.01) respectively. CONCLUSION: Our study suggests that pre-treatment NLR may be associated with DFS and OS patients with early TNBC. Further validation and a feasibility study are required before it can be considered for clinical use