764 research outputs found

    Vehicular traffic optimization in VANETs: a proposal for nodes re-routing and congestion reduction

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    Recently, vehicular networking has grown up in terms of interest and transmission capability, due to the possibility of exploiting the distributed communication paradigm in a mobile scenario, where moving nodes are represented by vehicles. In this paper, we focus our attention on the optimization of traffic flowing in a vehicular environment with vehicle-roadside capability. As shown in the next sections, the proposed idea exploits the information that is gathered by road-side units with the main aim of redirecting traffic flows (in terms of vehicles) to less congested roads, with an overall system optimization, also in terms of Carbon Dioxide emissions reduction. A deep campaign of simulations has been carried out to give more effectiveness to our proposal

    Vehicular networking enhancement and multi-channel routing optimization, based on multi-objective metric and minimum spanning tree

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    Vehicular Ad hoc NETworks (VANETs) represent a particular mobile technology that permits the communication among vehicles, offering security and comfort. Nowadays, distributed mobile wireless computing is becoming a very important communications paradigm, due to its flexibility to adapt to different mobile applications. VANETs are a practical example of data exchanging among real mobile nodes. To enable communications within an ad-hoc network, characterized by continuous node movements, routing protocols are needed to react to frequent changes in network topology. In this paper, the attention is focused mainly on the network layer of VANETs, proposing a novel approach to reduce the interference level during mobile transmission, based on the multi-channel nature of IEEE 802.11p (1609.4) standard. In this work a new routing protocol based on Distance Vector algorithm is presented to reduce the delay end to end and to increase packet delivery ratio (PDR) and throughput in VANETs. A new metric is also proposed, based on the maximization of the average Signal-to-Interference Ratio (SIR) level and the link duration probability between two VANET nodes. In order to relieve the effects of the co-channel interference perceived by mobile nodes, transmission channels are switched on a basis of a periodical SIR evaluation. A Network Simulator has been used for implementing and testing the proposed idea

    The addition of simvastatin administration to cold storage solution of explanted whole liver grafts for facing ischemia/reperfusion injury in an area with a low rate of deceased donation: a monocentric randomized controlled double-blinded phase 2 study.

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    BACKGROUND: Liver transplantation is the best treatment for end-stage liver disease. The interruption of the blood supply to the donor liver during cold storage damages the liver, affecting how well the liver will function after transplant. The drug Simvastatin may help to protect donor livers against this damage and improve outcomes for transplant recipients. The aim of this study is to evaluate the benefits of treating the donor liver with Simvastatin compared with the standard transplant procedure. PATIENT AND METHODS: We propose a prospective, double-blinded, randomized phase 2 study of 2 parallel groups of eligible adult patients. We will compare 3-month, 6-month, and 12-month graft survival after LT, in order to identify a significant relation between the two homogenous groups of LT patients. The two groups only differ by the Simvastatin or placebo administration regimen while following the same procedure, with identical surgical instruments, and medical and nursing skilled staff. To reach these goals, we determined that we needed to recruit 106 patients. This sample size achieves 90% power to detect a difference of 14.6% between the two groups survival using a one-sided binomial test. DISCUSSION: This trial is designed to confirm the effectiveness of Simvastatin to protect healthy and steatotic livers undergoing cold storage and warm reperfusion before transplantation and to evaluate if the addition of Simvastatin translates into improved graft outcomes. TRIAL REGISTRATION: ISRCTN27083228

    Edwards INSPIRIS RESILIA Valve for Aortic Valve Replacement Achieves Acute Reverse Remodelling of the Left Ventricle and Maintains Excellent Hemodynamic Profile after 1 Year in Young Adults

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    Objective: Mechanical aortic valve replacement (AVR) is still the recommended valve substitute in young adults, although cultural reasons have popularized bioprostheses also in these patients. Inde..

    Cardioplegia between evolution and revolution: from depolarized to polarized cardiac arrest in adult cardiac surgery

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    Despite current advances in perioperative care, intraoperative myocardial protection during cardiac surgery has not kept the same pace. High potassium cardioplegic solutions were introduced in the 1950s, and in the early 1960s they were soon recognized as harmful. Since that time, surgeons have minimized many of the adverse effects by lowering the temperature of the heart, lowering K+ concentration, reducing contact K+ time, changing the vehicle from a crystalloid solution to whole-blood, adding many pharmacological protectants and modifying reperfusion conditions. Despite these attempts, high potassium remains a suboptimalway to arrest the heart. We briefly review the historical advances and failures of finding alternatives to high potassium, the drawbacks of a prolonged depolarized membrane, altered Ca2+ intracellular circuits and heterogeneity in atrial-ventricular K+ repolarization during reanimation. Many of these untoward effects may be alleviated by a polarized membrane, and we will discuss the basic science and clinical experience from a number of institutions trialling different alternatives, and our institution with a non-depolarizing adenosine, lidocaine and magnesium (ALM) cardioplegia. The future of polarized arrest is an exciting one and may play an important role in treating the next generation of patients who are older, and sicker with multiple comorbidities and require more complex operations with prolonged cross-clamping times

    Case report: Trans-papillary free stenting of the cystic duct and of the common bile duct in a double biliary ducts anastomoses of a right lobe living donor transplantation

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    Background: One of the major issues related to the living donor liver transplantation recipient outcome is still the high rate of biliary complication, especially when multiple biliary ducts are present and multiple anastomoses have to be performed. Case presentation and conclusion: We report a case of adult-to-adult right lobe living donor liver transplantation performed for a recipient afected by alcohol-related cirrhosis with MELD score of 17. End-stage liver disease was complicated by refractory ascites, portal hypertension, small esophageal varices and portal gastropathy, hypersplenism, and abundant right pleural efusion. Here in the attached video we described the adult-to-adult LDLT procedures, where a right lobe with two biliary ducts draining respectively the right anterior and the right posterior segments has been transplanted. LDLT required a biliary reconstruction using the native cystic and common bile ducts stented trans-papillary with two 5- French 6 cm long soft silastic catheter. None major complications were detected during post-operative clinical courses. Actually, the donor and the recipient are alive and well. The technique we describe in the video, allow to keep the biliary anastomoses protected and patent without having the risk of creating cholestasis and the need of invasive additional procedure. No living donor right lobe transplantation should be refused because of the presence of multiple biliary ducts

    Left ventricular remodeling in hypertrophic cardiomyopathy: an overview of current knowledge

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    While most patients with hypertrophic cardiomyopathy (HCM) show a relatively stable morphologic and clinical phenotype, in some others, progressive changes in the left ventricular (LV) wall thickness, cavity size, and function, defined, overall, as "LV remodeling", may occur. The interplay of multiple pathophysiologic mechanisms, from genetic background to myocardial ischemia and fibrosis, is implicated in this process. Different patterns of LV remodeling have been recognized and are associated with a specific impact on the clinical course and management of the disease. These findings underline the need for and the importance of serial multimodal clinical and instrumental evaluations to identify and further characterize the LV remodeling phenomenon. A more complete definition of the stages of the disease may present a chance to improve the management of HCM patients

    A Therapeutic and Diagnostic Multidisciplinary Pathway for Merkel Cell Carcinoma Patients

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    Merkel Cell Carcinoma (MCC) is a highly aggressive neuroendocrine neoplasm of the skin. Due to its rarity, the management of MCC is not standardized across centers. In this article, we present the experience of the Veneto region in the North-East of Italy, where a committee of skin cancer experts has proposed a clinical pathway for the diagnosis and treatment of MCC. Putting together the evidence available in the international literature, we outlined the best approach to the management of patients affected with this malignancy step- by- step for each possible clinical situation. Crucial in this pathway is the role of the multidisciplinary team to deal with the lack of robust information on each aspect of the management of this disease

    Prognostic factors in merkel cell carcinoma: A retrospective single-center study in 90 patients

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    Abstract Merkel Cell Carcinoma (MCC) is a rare but highly aggressive neuroendocrine neoplasm of the skin. This study aimed at describing characteristics, treatment, and prognosis of a series of consecutive cases of MCC patients, in order to contribute to the investigation of this rare malignancy and provide better patient care. This is a retrospective cohort study including all 90 patients diagnosed and/or treated for MCC between 1991 and 2018 at the Veneto Institute of Oncology in Padua (Italy). Patient and tumor characteristics, treatment, and immunohistochemical data were extracted from a prospectively collected local database. There were 68 primary (76%) and 22 non-primary (15 occult primary, three metastatic, four recurrence) tumors (24%). CK20 expression was associated with reduced overall (HR 2.92, 95% CI 1.04-8.16) and disease-specific (HR 4.62, 95% CI 1.31-16.28) survival. Immunomodulatory regimens for treatment of other comorbidities were associated with reduced disease-specific ((HR 2.15, 95% CI 1.06-4.36) and recurrence-free (HR 3.08, 95% CI 1.44-6.57) survival. latrogenic immunomodulation resulted as the main factor associated with impaired prognosis. Lack of CK20 expression was associated with better survival
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