Reliable and efficient forwarding in ad hoc networks

This paper focuses on packet forwarding in ad hoc networks and proposes a new approach to improve performance of nodes communication. In particular, we present a lightweight mechanism for REliable and Efficient Forwarding (REEF), which mitigates the effects of adverse situations caused by cooperation misbehavior or network fault conditions. It exploits nodes’ local knowledge to estimates route reliability, and multi-path routing to forward packets on the most reliable route. REEF becomes also a security mechanism in case of a security association established between the communication parties. This additional feature makes the mechanism robust, guaranteeing trustworthiness of the reliability estimator and security of data transmission.A new approach to cooperation enforcing is also proposed. The classical method denies service to misbehaving nodes by, for example, not serving their forwarding requests. We approach the problem less drastically, differentiating the quality of service provided to nodes according to their behavior. In other words, traffic of misbehaving nodes will flow through the network slower than that one of reliable nodes.     

Electrochemical synthesis and characterization of poly[3-(ω-bromoalkyl)thiophene]s

A novel series of functionalized polythiophenes incorporating 3-(ω-bromoalkyl) pendants are synthesized by electrochemical polymerization. The effect of the solvent on the electrosynthesis is investigated. The polymeric films are characterized using cyclic voltammetry, FT-IR, AFM and SEM microscopy. The poly[3-(6-bromohexyl)thiophene] film cast on GC or ITO electrode surface is compared with a sample obtained by a chemical method.     

About some corrosion mechanisms of AZ91D magnesium alloy

The present work is dedicated to a study of the corrosion resistance of AZ91D (91% Mg) alloy in wet environments. Three industrial alloys obtained by die-casting or sand casting were subjected to salt spray corrosion tests (ASTM-B117 standard) and immersion tests. Weight loss kinetic curves were measured. Surface analysis was performed by X-ray photoelectron diffraction (XPS). After corrosion the sand cast alloy presents a surface mainly enriched in hydroxides and carbonates while the die-cast alloy presents a surface enriched also in mixed Mg-Al oxides. The quantitative analysis of the rate Mg/Al shows an enrichment in aluminium for the die-cast alloys in comparison to the sand cast alloy.     

Control of the oxygen dependence of an implantable polymer/enzyme composite biosensor for glutamate

Biosensors for glutamate (Glu) were fabricated from Teflon-coated Pt wire (cylinders and disks), modified with the enzyme glutamate oxidase (GluOx) and electrosynthesized polymer PPD, poly(o-phenylenediamine). The polymer/enzyme layer was deposited in two configurations: enzyme before polymer (GluOx/PPD) and enzyme after polymer (PPD/GluOx). These four biosensor designs were characterized in terms of response time, limit of detection, Michaelis-Menten parameters for Glu (J max and K(M)(Glu)), sensitivity to Glu in the linear response region, and dependence on oxygen concentration, K(M)(O2). Analysis showed that the two polymer/enzyme configurations behaved similarly on both cylinders and disks. Although the two geometries showed different behaviors, these differences could be explained in terms of higher enzyme loading density on the disks; in many analyses, the four designs behaved like a single population with a range of GluOx loading. Enzyme loading was the key to controlling the K(M)(O2) values of these first generation biosensors. The counterintuitive, and beneficial, behavior that biosensors with higher GluOx loading displayed a lower oxygen dependence was explained in terms of the effects of enzyme loading on the affinity of GluOx for its anionic substrate. Some differences between the properties of surface immobilized GluOx and glucose oxidase are highlighted.     

How does the application of an IT service innovation affect firm performance? A theoretical framework and empirical analysis on e-commerce

Understanding the effects of IT-related innovations on firm performance is crucial for businesses. Extant research has investigated the implications of IT innovations and provided some important findings, but the varied theoretical approaches have produced results that are often ambiguous: thus there is a need to examine the process further. We attempted to provide a systematic, theoretically informed framework for understanding the conditions that may enhance (or hinder) the potential of IT innovations in a sample of firms. Our model included business and IT resources, both internal and external, that may influence the performance of firms which have applied a pervasive IT service innovation: e-commerce. Our empirical test of the model used a research design that takes into account time-lag effects. The model explained more than half of the variance in the performance of IT innovators and offered several explanations for why some firms succeeded in implementing IT service innovations while others did not. Several theoretical and managerial implications result from these findings.     

Long-term treatment with cabergoline, a new long-lasting ergoline derivate, in idiopathic or tumorous hyperprolactinaemia and outcome of drug-induced pregnancy

Cabergoline (CAB), a new long-acting ergoline derivative, was shown to be very effective in reducing PRL levels in normal volunteers and in hyperprolactinemic patients. We evaluated the hormonal changes after discontinuation of long-term therapy with CAB as well as the safety of drug exposure during pregnancy both for mothers and babies. We therefore studied 48 patients (47 females and one male) with pathological hyperprolactinaemia (mean +/- SE, 117.2 +/- 15.2: median 73.2 micrograms/l), treated for 1-82 months (mean +/- SE, 28.3 +/- 3; median 18). After long-term treatment, CAB was withdrawn in 11 patients and PRL levels were persistently normal for almost 15 days and significantly lower (p < 0.05) than basal at 30, 45, 60, 90, 120 days. Three patients had normal PRL levels still at 45 days after treatment discontinuation. Nine patients became pregnant after 1-37 months (mean 12.4) of therapy. In two patients the pregnancy was interrupted spontaneously in one case and voluntarily in the other. In all but one patients after delivery or three-month breast feeding, PRL levels trended towards reduction. In two cases (one with microadenoma and one with idiopathic hyperprolactinaemia) PRL remained in the normal levels for 1-3 years after delivery. In conclusion CAB is able to inhibit plasma PRL levels for long time (up to 120 days) after withdrawal in patients with pathological hyperprolactinaemia treated with long-term therapy.     

Skin permeation of 5-methoxypsoralen from topical dosage forms

The topical photochemotherapy of dermatoses with psoralens (PUVA therapy) requires an adequate drug level at the target site (basal epidermis) at the time of UVA radiation. The aim of this work was to enhance 5-methoxypsoralen transport to the basal epidermis, with the goal to shorten the delay between drug application and UVA irradiation. 5-Methoxypsoralen transport through rabbit skin was studied in vitro from topical formulations (water solution, gel, and emulsion). The results obtained show that the use of the emulsion increased the flux through rabbit ear skin, even if partitioning was not favorable. Additionally, the time lag was sensibly reduced, compared with the gel and solution. Furthermore, drug accumulation in human skin in vitro was determined using the thin slicing technique. Human skin accumulation profile was significantly higher for the emulsion, compared with the gel, indicating that the delay between psoralen application and UVA irradiation can be shortened.     

Multiple Roles for Cytokines in Atopic Dermatitis: From Pathogenic Mediators to Endotype-Specific Biomarkers to Therapeutic Targets

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases, which generally presents with intense itching and recurrent eczematous lesions. AD affects up to 20% of children and 10% of adults in high-income countries. The prevalence and incidence of AD have increased in recent years. The onset of AD mostly occurs in childhood, although in some cases AD may persist in adult life or even manifest in middle age (adult-onset AD). AD pathophysiology is made of a complex net, in which genetic background, skin barrier dysfunction, innate and adaptive immune responses, as well as itch contribute to disease development, progression, and chronicization. One of the most important features of AD is skin dehydration, which is mainly caused by filaggrin mutations that determine trans-epidermal water loss, pH alterations, and antigen penetration. In accordance with the “outside-inside” theory of AD pathogenesis, in a context of an altered epidermal barrier, antigens encounter epidermal antigen presentation cells (APCs), such as epidermal Langerhans cells and inflammatory epidermal dendritic cells, leading to their maturation and Th-2 cell-mediated inflammation. APCs also bear trimeric high-affinity receptors for immunoglobulin E (IgE), which induce IgE-mediated sensitizations as part of pathogenic mechanisms leading to AD. In this review, we discuss the role of cytokines in the pathogenesis of AD, considering patients with various clinical AD phenotypes. Moreover, we describe the cytokine patterns in patients with AD at different phases of the disease evolution, as well as in relation to different phenotypes/endotypes, including age, race, and intrinsic/extrinsic subtypes. We also discuss the outcomes of current biologics for AD, which corroborate the presence of multiple cytokine axes involved in the background of AD. A deep insight into the correlation between cytokine patterns and the related clinical forms of AD is a crucial step towards increasingly personalized, and therefore more efficient therapy.     

An approximate A algorithm and its application to the SCS problem

In this paper we deal with algorithm A^* and its application to the problem of finding the shortest common supersequence of a set of sequences. A^* is a powerful search algorithm which may be used to carry out concurrently the construction of a network and the solution of a shortest path problem on it. We prove a general approximation property of A^* which, by building a smaller network, allows us to find a solution with a given approximation ratio. This is particularly useful when dealing with large instances of some problem. We apply this approach to the solution of the shortest common supersequence problem and show its effectiveness.