259 research outputs found
Development of a new tracking device for characterization and monitoring of ultra fast neutron beams
No full textNeutron radiation fields are generated in various scientific research areas and applications, for example in radiation therapy, in radionuclide production for medical applications, in material science studies, for design of electronic components in energy production, military activities, and in neutron radiography. Moreover, high energy neutrons are the dominant component of the prompt radiation field present outside the shielding of high-energy accelerators and are a significant component of the cosmic radiation fields interacting with aircrafts and in spacecrafts.
The Space Agencies programs are focusing on human space exploration. The return to the moon and the construction of a permanent base (Moon Village) and the Mars exploration are now among the highest priorities both for NASA and ESA. However, the health risks caused by exposure to cosmic radiation are acknowledged as one of the major showstopper for safe colonization of the Solar systems. Shielding is the only practical countermeasure available, but there is still a lack of information regarding the neutrons stopping performances of the new materials currently under evaluation in the context of long term space missions (e.g. highly hydrogenated materials, in situ resource utilizations and active shields). The recently founded SPARE project aims to carry out a shielding test campaign of active and passive materials using high energy protons and neutrons at the accelerator facilities in Trento (TIFPA) and Legnaro (SPES- Laboratori Nazionali di Legnaro LNL). For this reason the development of a new Quasi Monoenergetic Neutron (QMN) sources capable of accelerating neutrons with energies up to 70MeV in LNL will be a major goal of the project since no other QMN facility is currently in operation in Europe. An innovative detector (MONDO) developed by the "Museo Storico della Fisica e Centro Studi e Ricerca E.Fermi", able to track both neutrons and charged particles, will be used to measure the radiation transmitted and emitted by the shielding. The aim of this thesis is to present the MONDO neutron tracker and to describe its application within the SPARE project with a particular focus on its application as Neutron Beam Monitor for the new NEPIR QMN facility planned at LNL. Chapter 1 is dedicated to the description of the basic principles of neutron physics and dosimetry with a focus on the possible applications in space and Particle Therapy. An overview about the existing Quasi Mono-energetic Neutron facilities is also presented. The chapter conclusion contains an overview of the SPARE project. Chapter 2 is dedicated to the MONDO detector: the detection techniques and the tracker development status are described. The characterisation measurements already performed on a small MONDO prototype are also presented.
In Chapter 3 a detailed description of the MONDO readout system, the SBAM sensor, is presented.
Chapter 4 is dedicated to the presentation of the detector performances evaluated by means of a full-Montecarlo simulation in FLUKA.
In the last Chapter (5) measurements on the first sensor chip with different source are illustrated
Treatment options for refractory ulcerative colitis: Small molecules, big effects
No full textAlthough the majority of patients with ulcerative colitis (UC) have a mild-to-moderate disease, approximately 10%–15% experience a severe disease course and require immunosuppressive therapies.1 A better understanding of the mechanisms sustaining the pathogenic process in inflammatory bowel diseases (IBD) has largely contributed to expand the therapeutic armamentarium for this group of patients. Alongside with conventional therapies, monoclonal antibodies against tumour necrosis factor-α, α4β7 integrin (vedolizumab), interleukin (IL)-12/IL-23 p40 subunit (ustekinumab), and small molecules inhibiting intracellular pathways downstream to cytokine receptors (tofacitinib, filogotinib and upadacitinib), have entered into the clinic for the treatment of UC.2 However, selecting the appropriate medical therapy for each patient at a given stage of the disease natural history is an increasingly complex task for clinicians, as no prediction for treatment effect can be made in the individual patient
Vedolizumab and new‐onset spondyloarthritis: debunking the myth
No full textDespite an increased understanding of the etiopathogenesis of Inflammatory Bowel Disease (IBD), prevention or cure remains a distant aspiration and current treatment approaches often do not achieve long‐term disease remission. An additional complexity is that IBD can also be associated with a range of extra‐intestinal manifestations (EIMs). Among these EIMs, peripheral and axial rheumatological manifestations are perhaps the most prevalent, grouped under the term spondyloarthritis (SpA). The presentation of SpA can be before or after IBD diagnosis and presents several unique challenges. Notably, the presence of SpA can significantly impact on quality of life for patients and influence therapeutic decision‐making
Organic Scintillator
No full textThe invention relates to organic scintillators with improved characteristics in terms of transparency and response speed. More specifically, the scintillators of the invention use the chemical compounds of formula (M), also called fluorophores: (M) wherein: X and Y, independently of each other, are: H, aryl, naphthyl, biphenyl, tolyl, preferably 2-naphthyl, 1-naphthyl, 2-biphenyl, 4-tolyl; with the proviso that X and Y are never H at the same time; R1 and R2, independently of each other, are: aryl, arylalkyl, alkyl (also alkylene), with linear branched or cyclic chain C2-C12, preferably at least one of R1 and R2, or both, is C8H17
An overview of the role of innate lymphoid cells in gut infections and inflammation
No full textInnate lymphoid cells (ILCs) are a group of hematopoietic cells devoid of antigen receptors that have important functions in lymphoid organogenesis, in the defense against extracellular pathogens, and in the maintenance of the epithelial barrier. Three distinct groups of ILCs have been identified on the basis of phenotypic and functional criteria and termed ILCs1, ILCs2, and ILCs3. Specifically, ILCs1 express the transcription factor T-bet and secrete T helper type-1- (Th1-) related cytokines, ILCs2 are dependent on the transcription factor RORα and express Gata-3 and the chemokine receptor homologous molecule (CRTH2) and produce Th2-related cytokines, and ILCs3 express the transcription factor RORγt and synthesize interleukin- (IL-) 17, IL-22, and, under specific stimuli, interferon-γ. ILCs represent a relatively small population in the gut, but accumulating evidence suggests that these cells could play a decisive role in orchestrating both protective and detrimental immune responses. In this review, we will summarize the present knowledge on the distribution of ILCs in the intestinal mucosa, with particular focus on their role in the control of both infections and effector cytokine response in immune-mediated pathologies. © 2014 Silvia Sedda et al
Antisense Oligonucleotide: Basic Concepts and Therapeutic Application in Inflammatory Bowel Disease
No full textSeveral molecular technologies aimed at regulating gene expression that have been recently developed as a strategy to combat inflammatory and neoplastic diseases. Among these, antisense technology is a specific, rapid, and potentially high-throughput approach for inhibiting gene expression through recognition of cellular RNAs. Advances in the understanding of the molecular mechanisms that drive tissue damage in different inflammatory diseases, including Crohn’s disease (CD) and ulcerative colitis (UC), the two major inflammatory bowel diseases (IBDs) in humans, have facilitated the identification of novel druggable targets and offered interesting therapeutic perspectives for the treatment of patients. This short review provides a comprehensive understanding of the basic concepts underlying the mechanism of action of the oligonucleotide therapeutics, and summarizes the available pre-clinical and clinical data for oligonucleotide-based therapy in IBD
Optical readout of a triple-GEM detector by means of a CMOS sensor
No full textIn last years, the development of optical sensors has produced objects able to provide very interesting performance. Large granularity is offered along with a very high sensitivity. CMOS sensors with millions of pixels able to detect as few as two or three photons per pixel are commercially available and can be used to read-out the optical signals provided by tracking particle detectors. In this work the results obtained by optically reading-out a triple-GEM detector by a commercial CMOS sensor will be presented. A standard detector was assembled with a transparent window below the third GEM allowing the light to get out. The detector is supplied with an Ar/CF4 based gas mixture producing 650 nm wavelength photons matching the maximum quantum efficiency of the senso
Metalloproteinases in inflammatory bowel diseases
No full textInflammatory bowel diseases (IBD) are chronic inflammatory diseases of the gastrointestinal tract, encompassing two main disorders: Crohn's disease (CD) and ulcerative colitis (UC). In both these pathologies, excessive and local immune response against luminal antigens promotes a pathological process leading to various degrees of gut damage. Matrix metalloproteinases (MMPs) are a family of neutral proteases with the ability to degrade all components of extracellular matrix. In physiological conditions, MMPs are produced at very low level and generally in the latent form and are involved in the normal tissue turnover. Their function is inhibited by tissue inhibitors of metalloproteinases (TIMPs). However, in inflamed tissue of IBD patients, MMPs are produced in excess and/or the activity of TIMPs is not sufficient to block MMPs, thereby making a major contribution to the IBD-related mucosal degradation. In this review, we summarize the available evidence on the expression and role of MMPs in IBD
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