A Lumped Parameter Model for the Pressure and Vibration Analysis of Variable Displacement Vane Pumps

This PhD thesis presents a lumped parameter model able to simulate the vibrational behavior of a wide range of variable displacement vane pumps. The vibration analysis of the rotating parts is carried out through a planar model with three degrees of freedom. It takes into account the variability of the pressure loads acting on the rotor shaft, the hydrodynamic journal bearing reactions, the friction due to viscous actions and contact forces, the rotor shaft stiffness and damping, the variation of the pump geometry with respect to working condition and all the inertia actions. In particular, the computation of pressure forces and torques is allowed by the preliminary evaluation of the variable pressure field acting inside the pump, obtained through a model based on an Euler’s approach with 26 control volumes. Thus, the present model makes it possible to define the pressure field acting inside the pump, and calculate the rotor shaft accelerations, as well as the journal bearing reaction forces and the motor drive torque absorbed by the pump in working condition. The test campaign and the validation method are then described: an original assessment technique based on the comparison of pump casing accelerations is proposed. Finally, some important simulation results are reported as an example of application. The main original contribution of this work concerns the development of a nonlinear model of variable displacement vane pumps including all the important dynamic effects in the same model, with the aim at taking into account their iterations. This can be important in order to foresee the influence of working conditions and design modifications on the pump vibrational behavior. In this sense the developed lumped parameter model could be a very useful tool in prototype design, in order to identify the origin of unwanted dynamic effects

Antigen-presentation of non-peptidic antigens lipid trafficking and loading

T cells recognize a broad variety of antigens, including peptides, lipids and non-peptidic phosphorylated metabolites. Clarification of the rules rendering non-peptidic molecules immunogenic is essential to understand and to influence the reactions of the immune system to this class of substances in health and disease. Despite recent advances in research about immune responses to non-peptidic compounds, important issues remain unanswered. Molecular mechanisms governing the immunogenicity of non-peptidic ligands such as their cell internalization, trafficking within intracellular organelles, association with dedicated antigen-presenting molecules, induction of central and peripheral tolerance, and finally their role in autoimmune diseases as well as in protection during infections are unknown to date. The aims of this thesis were to assess some of the immunological functions and cell biological rules governing the immunogenicity of non-peptidic antigens, with particular emphasis on cell trafficking of non-peptidic antigens and antigen-presenting molecules. It focused on (i) the antigen reactivity and presence of human invariant natural killer T (iNKT) cells in diseases, (ii) the role of CD1a trafficking in lipid antigen presentation by this protein, and (iii) the requirements of membrane translocation of phosphorylated mevalonate metabolites that stimulate human T cell receptor (TCR) gamma-delta cells. With the development of alpha-galactosylceramide (alpha-GC)-loaded soluble CD1d dimers, which specifically interact with the TCR of iNKT cells, we have the perfect tool in our hands to perform detailed studies on iNKT cells. Analysis of the iNKT cells in blood unveiled large differences in their fluorescence intensity suggesting the presence of semi-invariant iNKT TCR with large disparities in the affinity for the alpha-GC-CD1d complex. Unexpectedly, established iNKT cell clones showed no correlation between CD1d dimer-staining levels and alpha-GC reactivity, indicating that additional mechanisms control responsiveness of iNKT cells, at least to this lipid antigen. The identification of lipid antigens stimulating exclusively some desired functions in human iNKT cells might lead to new medical therapies or vaccines. To screen a variety of synthetic lipids for their capacity to activate iNKT cells, we devised an in vitro model based on plastic-bound CD1d. Piperidinones, molecules with a ceramide- or sphingosine-like structure, revealed that a single lipid tail is sufficient to form stimulatory complexes with CD1d. Interestingly, piperidinones preferentially induce TH1-like cytokines, predicting a possible role as novel leader molecules to functionally direct iNKT cell responses deployable in clinical therapies. The balance of proinflammatory TH1 to regulatory TH2 cytokines is well-known to be decisive for the outcome of many diseases. Atherosclerosis (ATH) is a chronic inflammatory disease characterized by lipid accumulation in plaques. The disease is complicated by cardiovascular events provoked by plaque rupture or erosion. Because inflammation participates in lesion progression and rupture of plaques, the identification of its causes and of the culprit leukocyte populations involved in plaque destabilization is crucial for effective prevention of cardiovascular events. We used CD1d dimers to detect and characterize iNKT cells in ATH patients. We found that, in human atherosclerotic lesions, the abundance of CD1d-positive antigen-presenting cells (APC) and of iNKT cells correlates with disease severity and activity. CD1d-positive cells colonize advanced plaques in symptomatic patients and are most abundant in plaques with concomitant signs of ectopic neovascularization. In plaques, the frequency of iNKT cells among total T cells exceeds the one in blood. After having successfully isolated iNKT cell lines from plaque tissue, we showed that they promptly release proinflammatory cytokines upon lipid antigen stimulation and promote endothelial cell migration and microvascular sprout formation in vitro. This functional proangiogenic activity is ascribed to interleukin-8 released by iNKT cells after lipid recognition. These findings introduce iNKT cells as novel candidates to induce plaque neovascularization and destabilization in human ATH. Targeting iNKT cells could lead to late stage ATH treatment. Another approach to understand the role of lipid-specific immune responses is to investigate the molecular rules of lipid-CD1 complex formation. Lipids distribute, due to their physicochemical properties or with the help of specific transporters and lipid transfer proteins, to different intracellular compartments and membrane domains. Thus, it is advantageous for the immune system to utilize multiple CD1 isoforms, each with a distinct trafficking pattern, to facilitate sampling of lipid antigens localized in various membranes. Several studies have addressed trafficking of CD1 isoforms. However, the molecular mechanisms are known in only a few cases. We identified invariant chain (Ii) and lipid rafts as key regulators of CD1a organization on the surface of APC and of its immunological function as antigen-presenting molecule. Colocalization of CD1a with Ii is dependent on raft integrity and CD1a internalization is increased by Ii. The localization of CD1a in lipid rafts is functionally relevant as raft disruption inhibits CD1a-restricted antigen presentation. Moreover, we found that CD1a is internalized independently of clathrin and dynamin and that it follows a Rab22a- and adenosine diphosphate ribosylation factor (ARF) 6-dependent recycling pathway, similar to other clathrin-independent cargo. Posttranslational S-acylation of the CD1a cytoplasmic tail may occur but neither determines the rate of internalization nor recycling nor its localization to detergent-resistant membrane microdomains. These findings place CD1a close to major histocompatibility complex (MHC) class I in its trafficking routes although CD1a loads lipids in recycling endosomes and not in the endoplasmic reticulum as MHC class I. Strikingly, the glycolipid antigen sulfatide was found localized predominantly to early and recycling endosomes where CD1a is located. Swapping the cytoplasmic tail of CD1a for the one of CD1b and hence targeting the CD1a protein to the late endosomal and lysosomal compartments decreases its capacity to present sulfatide and shortens the half-life of stimulatory complexes. Thus, the physiological intracellular trafficking route of CD1a is critical for efficient presentation of lipid antigens that traffic through the early endocytic and recycling pathways. Intracellular trafficking of another class of non-peptidic antigens, namely the phosphorylated metabolites which stimulate human TCR gamma-delta cells expressing the Vgamma9/Vdelta2 heterodimer, was examined. These T cells recognize a family of structurally related compounds produced in the eukaryotic mevalonate and prokaryotic methylerythritol phosphate (MEP) pathways. The endogenous self-ligands are generated within the cytoplasm and must cross the membrane in order to associate with dedicated antigen-presenting molecules, which remain unknown at present. Using an in vitro transport assay, we demonstrated that the multidrug resistance-associated protein (MRP) 5 transporter is involved in membrane translocation of antigenic phosphorylated metabolites. Confocal microscopy illustrated that MRP5 is located in membranes of both endoplasmic reticulum and early endosomes. Both the intracellular localization and active role in antigen transport confer an immunological function to MRP5, resembling that of TAP (transporter associated with antigen processing) transporters involved in peptide antigen translocation. This indicates a similar strategy used for antigen presentation to TCR alpha-beta and gamma-delta T cells. In conclusion, these studies have underlined the physiological relevance of T cells recognizing non-peptidic ligands and have revealed unanticipated molecular mechanisms controlling the efficient presentation of such antigens

Risk, Human Behavior, and Theories inOrganizational Studies

The present paper regards risk, threats and organizational issues that are associated with human behavior;e.Business is no exception[2]. Organizational actors in e.Businessorganizations make security decisions with a wide variety of meanings[3]: information systems interactions, access to physical premises, behavior within the workplace, utilization of tools and work instruments, are just a few examples of the realm of security decisions that are made within all organizations, and e.Business organizations in particular. The way in which the risk is perceived greatly influences any decision. The aim of the present paper is to conjugate general risk theories in terms of human behavior and system security (as opposed to system risk) in order to identify a common baseline ofrisk and behavior, that will lead eventually lead to a structured framework that will contribute to the discipline of organizational studies

Innovative security techniques to prevent attacks on wireless payment on mobile android OS

Mobile technologies are increasingly pervading a substantial portion of everyday life. In particular, the economic sector of consumers and private sales has shown a very high rate of utilization of mobile applications. Mobile payments are no exception, and the economic development relies more and more on mobile technologies. Bank institutions and financial firms are privileged targets for cyber attacks and organized crime, exploiting vulnerabilities of smart mobile devices in particular for host card emulation wireless payments. The research analysis was based on mobile platform Android and identified ten original (novel) controls that can avoid possible attacks on payment transactions and/or privacy. The study has practical implications as practitioners and organizations, like banks, shall control the risks associated with the taxonomy of tamper IDs. Organizational implications can be regarded as the need for banks to look into software development for mobile applications

Performance Management and Innovative Human Resource Training through Flexible Production Systems aimed at Enhancing the Competitiveness of SMEs

In the current knowledge economy companies need to develop competitive advantages based on an adequate and intensive use of innovation processes and ICT that are becoming essential elements of business success in today’s European market. The purpose of this article is to introduce and discuss the benefits of on-line training on automation and innovation fields and try to explain their organizational impact on small and medium-sized enterprises (SME). Besides, it tries to understand what are the main barriers for SMEs with respect to the realisation of their innovative potential and their capacity to improve internal processes by ICT adoption and organizational change. They are becoming particularly important for achieving greater productivity, lower operational costs, and higher revenues (usually characterized by reduced access to external finance, unavailability of wider distribution channels, low internationalization, etc.). The goal of the article is also to synthetize the experience done and the benefits of e-learning and of a specific professional environment in the training process. The described project provides training contents to enhance participants’ background and some innovative simulations to improve effectively the specialised knowledge of employees on industrial automation systems

Extensible Architectures: The Strategic Value of Service Oriented Architecture in Banking

Information and communication technology (ICT) has helped to drive increasingly intense global competition. In turn, this intensity increases the need for flexibility and rapid changeability in ICT to support strategies that depend on organizational agility. We report a comparative, cross-cultural case study of the implementation of Service Oriented Architectures (SOA) at a Scandinavian bank and a Swiss bank. The strategic rewards in the adoption of SOA appear to go beyond marketplace issues of ICT capability acquisition, and unexpectedly arise in the creation of an extensible organizational ICT architecture. The extensibility of the ICT architecture that results from the adoption of SOA provides potential for greater organizational agility (and thereby competitiveness)

Unexpected increase of myocardial extracellular volume fraction in low cardiovascular risk HIV patients

Background People living with HIV (PLWH) are prone to develop sub-clinical Cardiovascular (CV) disease, despite the effectiveness of combined Antiretroviral Therapy (cART). Algorithms developed to predict CV risk in the general population could be inaccurate when applied to PLWH. Myocardial Extra-Cellular Matrix (ECM) expansion, measured by computed tomography, has been associated with an increased CV vulnerability in HIV-negative population. Measurement of Myocardial Extra-Cellular Volume (ECV) by computed tomography or magnetic resonance, is considered a useful surrogate for clinical evaluation of ECM expansion. In the present study, we aimed to determine the extent of cardiovascular involvement in asymptomatic HIV-infected patients with the use of a comprehensive cardiac computed tomography (CCT) approach. Materials and methods In the present study, ECV in low atherosclerotic CV risk PLWH was compared with ECV of age and gender matched HIV- individuals. 53 asymptomatic HIV + individuals (45 males, age 48 (42.5–48) years) on effective cART (CD4 + cell count: 450 cells/µL (IQR: 328–750); plasma HIV RNA: <37 copies/ml in all subjects) and 18 age and gender matched controls (14 males, age 55 (44.5–56) years) were retrospectively enrolled. All participants underwent CCT protocol to obtain native and postcontrast Hounsfield unit values of blood and myocardium, ECM was calculated accordingly. Results The ECV was significantly higher in HIV + patients than in the control group (ECV: 31% (IQR: 28%-31%) vs. 27.4% (IQR: 25%-28%), p < 0.001). The duration of cART (standardized β = 0.56 (0.33–0.95), p = 0.014) and the years of exposure to HIV infection (standardized β = 0.53 (0.4–0.92), p < 0.001), were positively and strongly associated with ECV values. Differences in ECV (p < 0.001) were also observed regarding the duration of cART exposure (< 5 years, 5–10 years and > 10 years). Moreover, ECV was independently associated with age of participants (standardized β = 0.42 (0.33–0.89), p = 0.084). Conclusions HIV infection and exposure to antiretrovirals play a detrimental role on ECV expansion. An increase in ECV indicates ECM expansion, which has been associated to a higher CV risk in the general population. The non-invasive evaluation of ECM trough ECV could represent an important tool to further understand the relationship between HIV infection, cardiac pathophysiology and the increased CV risk observed in PLWH

Progress on Low-Temperature Pulsed Electron Deposition of CuInGaSe2 Solar Cells

The quest for single-stage deposition of CuInGaSe2 (CIGS) is an open race to replace very effective but capital intensive thin film solar cell manufacturing processes like multiple-stage coevaporation or sputtering combined with high pressure selenisation treatments. In this paper the most recent achievements of Low Temperature Pulsed Electron Deposition (LTPED), a novel single stage deposition process by which CIGS can be deposited at 250 °C, are presented and discussed. We show that selenium loss during the film deposition is not a problem with LTPED as good crystalline films are formed very close to the melting temperature of selenium. The mechanism of formation of good ohmic contacts between CIGS and Mo in the absence of any MoSe2 transition layers is also illustrated, followed by a brief summary of the measured characteristics of test solar cells grown by LTPED. The 17% efficiency target achieved by lab-scale CIGS devices without bandgap modulation, antireflection coating or K-doping is considered to be a crucial milestone along the path to the industrial scale-up of LTPED. The paper ends with a brief review of the open scientific and technological issues related to the scale-up and the possible future applications of the new technology