301 research outputs found
Hepatitis C virus infection and autoimmune diseases
No full textMarino Paroli,1 Gino Iannucci,2 Daniele Accapezzato21Department of Biotechnology and Medical-Surgical Sciences, 2Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, ItalyAbstract: Hepatitis C virus (HCV) infection is associated with a number of extrahepatic disorders. The most studied conditions associated with HCV are type II mixed cryoglobulinemia and B cell lymphoma. However, many reports suggest that HCV might also be associated with a number of autoimmune disorders, both organ-specific and not organ-specific. Although concomitant treatment of HCV infection is a confounding factor when ascertaining the actual role of HCV in inducing autoimmune disease, a considerable amount of experimental data indicates that HCV is able to subvert the immune system and consequently induce autoimmunity. In the present review, we report a series of observations which associate chronic HCV infection with the onset of autoimmune disorders.Keywords: hepatitis C virus, immune regulation, autoimmune disease
Development of diagnostic and manipulation systems for space-charge dominated electron beams and confined electron plasmas in ELTRAP
No full textModifications have been implemented in the Penning-Malmberg device ELTRAP aimed
at performing studies on the dynamics of space-charge dominated nanosecond electron bunches traveling along the magnetic field. In particular, a Thomson backscattering apparatus has been developed where an infrared (IR) laser pulse collides with the bunched electron beam. The frequency-shifted
backscattered radiation, acquired by means of a photomultiplier (PMT), can be exploited to evaluate information on energy, energy spread and density of the bunch. The achievable sensitivity
of the diagnostics has been estimated, and valuable information on the main parameters affecting the signal-to-noise (S/N) ratio has been obtained [B. Paroli, F. Cavaliere, M. Cavenago, F. De Luca, M. Ikram, G. Maero, C. Marini, R. Pozzoli, and M. Romé, JINST 7, P01008 (2012)]. A series of upgrades are under way, aimed at increasing the S/N ratio through the use of a new laser for the electron source, the insertion of a stray light shield, and the optimization of the detection electronics. Moreover, electromagnetic simulations relevant to the design and implementation of a microwave
heating system are presented. The generation of an electron plasma in ELTRAP by means of a low-power radio frequency (RF) drive in the MHz range applied on one of the trap electrodes and under ultra-high vacuum (UHV) conditions has previously been demonstrated [B. Paroli, F. De Luca,
G. Maero, F. Pozzoli, and M. Romé, Plasma Sources Sci. Technol. 19, 045013 (2010)]. The new heating system will allow the extension of the RF studies to the GHz range and in particular the
production of a more energetic electron plasma via cyclotron resonant excitation
Two-dimensional mapping of the asymmetric lateral coherence of thermal light
No full textWe report in this work the first experimental verification of the asymmetric lateral coherence which is a measurement of the spatio-temporal coherence by using a wide-band Young interference experiment with a fixed off-axis slit. We demonstrate the coherence properties through the measurement of the real part of the coherence factor of thermal light. We extend our recent results obtained for betatron and undulator radiations providing a robust experimental method for the two-dimensional mapping of the two-point correlation function of broadband radiation preserving the phase information. The proposed method can be used as a high-sensitivity alternative to traditional interferometry with quasi-monochromatic radiation
THOMSON BACKSCATTERING DIAGNOSTICS OF NANOSECOND ELECTRON BUNCHES IN HIGH SPACE CHARGE REGIME
No full textThe intra-beam repulsions play a significant role in determining the performances of free-electron devices when an high brilliance of the beam is required. The transversal and longitudinal spread of the beam, its energy and density are fundamental parameters in any beam experiment and different beam diagnostics are available to measure such parameters. A diagnostic method based on the Thomson backscattering of a laser beam impinging on the particle beam is proposed in this work for the study of nanosecond electron bunches in high space charge regime. This diagnostics, aimed to the measurement of density, energy and energy spread, was set-up in a Malmberg-Penning trap (generally used for the electron/ion confinment) in two different configurations designed to optimize sensitivity, spatial resolution and electron-beam coincidence in space and time. To this purpose an electron bunch (pulse time <4 ns), produced by a photocathode source, was preliminary characterized with different electrostatic diagnostics and used to test the diagnostics systems. The solutions are detailed, which were devised for both the laser and bunch injection in the vacuum chamber, space and time coincidence of electron and laser pulses, photon detection, optimization of the geometry in the laser-beam interaction. The results are then summarized with an estimate of the minimum sensitivity of the set-up
Radiation emission processes and properties: synchrotron, undulator and betatron radiation
No full textSynchrotron, undulator and betatron radiations are generated from last generation and novel concept sources. The achievement of unprecedented radiation properties opens new opportunities in various research fields as well as novel potential applications. In particular, bright coherent X-rays and (Formula presented.) -rays have been recently obtained thanks to enormous efforts in technological advancements and research activities. We give in this work a uniform argumentation and comparison of the main fundamental emission processes and radiation properties of synchrotron, undulator and betatron radiations. Emphasis is given to spatial coherence and related diagnostics, a fundamental property for any ‘modern light source’ and a basis for recent important advancements
METHOD AND SYSTEM FOR DEMULTIPLEXING AND DEMODULATING SIGNALS MULTIPLEXED IN THE VARIABLE ORBITAL ANGULAR MOMENTUM
No full textA method for demultiplexing and demodulating (in particular, "locally" demultiplexing and demodulating) amplitude-modulated signals grouped by means of orbital angular momentum multiplexing is described. The method involves demultiplexing and demodulating information a(t), b(t) modulated on each of a first modulated beam Fm1 and at least one second modulated beam Fm2, based on phase difference values AP and AR detected by beam detectors located downstream of an interferometric structure 40 to which two portions of the electromagnetic beam carrying the modulated channels are provided as inputs, multiplexed in the orbital angular momentum variable. There is also described a corresponding system 100 for demultiplexing and demodulating amplitude-modulated signals capable of implementing the aforesaid method
Asymmetric lateral coherence allows precise wavefront characterization
No full textWe describe a novel interferometric method for reconstructing a wavefront with high accuracy. By exploiting a proper scan of a double-slit array we experimentally show that the oscillations in the 2-dimensional map of the asymmetric lateral coherence are locally dilated or contracted as a function of the wavefront curvature, which produces a phase modulation of the real part of the complex degree of coherence. The proposed method can be used for high-resolution wavefront reconstruction from microwaves to X-rays
T-CELL RECOGNITION OF HEPATITIS-B ENVELOPE PROTEINS
No full textWe have studied the T-cell processing pathways of Hepatitis B antigens and the role of specific B lymphocytes. It could be shown that some form of processing by specific B cells is required for class I CTLs. This mechanism differs from class II endosomal processing. In addition, it could be shown that lysis of HBsAg-specific B cells may be partly responsible for chronic HBV carrier states
Advances in the pathogenesis and treatment of systemic lupus erythematosus
No full textSystemic lupus erythematosus (SLE) is a genetically predisposed, female-predominant disease, characterized by multiple organ damage, that in its most severe forms can be life-threatening. The pathogenesis of SLE is complex and involves cells of both innate and adaptive immunity. The distinguishing feature of SLE is the production of autoantibodies, with the formation of immune complexes that precipitate at the vascular level, causing organ damage. Although progress in understanding the pathogenesis of SLE has been slower than in other rheumatic diseases, new knowledge has recently led to the development of effective targeted therapies, that hold out hope for personalized therapy. However, the new drugs available to date are still an adjunct to conventional therapy, which is known to be toxic in the short and long term. The purpose of this review is to summarize recent advances in understanding the pathogenesis of the disease and discuss the results obtained from the use of new targeted drugs, with a look at future therapies that may be used in the absence of the current standard of care or may even cure this serious systemic autoimmune disease
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