Muon tomography effectiveness in detecting orphan sources in scrap metal

The detection of sealed orphan sources inside scrap metal transportation is a crucial concern for the steel industry, because an accidental melting of radioactive material can produce severe environmental harm. The technique of muon tomography appears to be suitable for this purpose, because it allows to discriminate high-Z materials, measuring multiple scattering of cosmic ray muons crossing the cargo. A European project (RFSR-CT-2010-000033) to exploit this technique started in 2010 and finished in 2012. The aim of the project was to design an inspection portal able to detect lead-shielded radioactive sources hidden in scrap metal containers using cosmic rays. The reconstruction algorithms and their performances were studied in a full simulated environment

Variação genética de uma população natural de Araucaria angustifolia (Bert) O. Ktze.

Resumo

Precision measurements of Linear Scattering Density using Muon Tomography

We demonstrate that muon tomography can be used to precisely measure the properties of various materials. The materials which have been considered have been extracted from an experimental blast furnace, including carbon (coke) and iron oxides, for which measurements of the linear scattering density relative to the mass density have been performed with an absolute precision of 10%. We report the procedures that are used in order to obtain such precision, and a discussion is presented to address the expected performance of the technique when applied to heavier materials. The results we obtain do not depend on the specific type of material considered and therefore they can be extended to any application.Comment: 16 pages, 4 figure

Accurate magnetic sensor system integrated design

Inductive measurement of magnetic fields is a diagnostic technique widely used in several scientific fields, such as magnetically confined fusion, plasma thrusters and particle accelerators, where real time control and detailed characterization of physics phenomena are required. The accuracy of the measured data strongly influences the machine controllability and the scientific results. In the framework of the assembly modifications of the RFX-mod experiment, a complete renew and improvement of the magnetic diagnostic system, from the probes moved inside the vacuum vessel to the integrator modules, has been carried out. In this paper, the whole system making up the magnetic diagnostics is described, following the acquisition chain from the probe to the streamed data and illustrating the requirements and conflicting limitations which affect the different components, in order to provide a comprehensive overview useful for an integrated design of any new systems. The characterization of a prototypical implementation of the whole acquisition chain is presented, focusing on the flexible ADC architecture adopted for providing a purely numerical signal integration, highlighting the advantages that this technology offers in terms of flexibility, compactness and cost effectiveness, along with the limitations found in existing implementation in terms of ADC noise characteristics and their possible solutions

Hydrogen peroxide is a neuronal alarmin that triggers specific RNAs, local translation of Annexin A2, and cytoskeletal remodeling in Schwann cells

Schwann cells are key players in neuro-regeneration: They sense "alarm" signals released by degenerating nerve terminals and differentiate toward a proregenerative phenotype, with phagocytosis of nerve debris and nerve guidance. At the murine neuromuscular junction, hydrogen peroxide (H2O2) is a key signal of Schwann cells' activation in response to a variety of nerve injuries. Here we report that Schwann cells exposed to low doses of H2O2 rewire the expression of several RNAs at both transcriptional and translational levels. Among the genes positively regulated at both levels, we identified an enriched cluster involved in cytoskeleton remodeling and cell migration, with the Annexin (Anxa) proteins being the most represented family. We show that both Annexin A2 (Anxa2) transcript and protein accumulate at the tips of long pseudopods that Schwann cells extend upon H2O2 exposure. Interestingly, Schwann cells reply to this signal and to nerve injury by locally translating Anxa2 in pseudopods, and undergo an extensive cytoskeleton remodeling. Our results show that, similarly to neurons, Schwann cells take advantage of local protein synthesis to change shape and move toward damaged axonal terminals to facilitate axonal regeneration

AEROBIC TRAINING WITH LIMBS INTERMITTENT ISCHEMIA IMPROVES MYOCARDIAL FUNCTION AND WALL STRETCH IN PATIENTS WITH CLAUDICATION

Background: peripheral arterial disease (PAD) is a chronic disease determining functional impairment and increased risk of cardiovascular events. Physical training improves cardiac performance and reduces NTproBNP concentration, marker of risk of cardiovascular events, in cardiac patients. Aim: we aimed to examine the effects training conducted till ischemic pain at the leg of PAD patients on myocardial function and peripheral flux.Methods: we enrolled 22 patients affected by peripheral arterial disease without cardiac disease. All patients undergone a physical training of 15 days, with treadmill test at the begin and at the end of training. Results: at the end of training patients increased walking distance (450\ub1180 m vs 250\ub1108 m; p<0.05). We documented at rest, at the end of physical training, an increase in flow volume of common femoral artery of the symptomatic leg (2,55\ub12,13 L/min vs 1,86\ub11,30 L/min; p<0.05); NTproBNP concentration at rest was lower al the end of training (210\ub1130 pg/mL vs 188\ub1108 pg/mL; p<0.005), an increase of NTproBNP concentration after maximal exercise on treadmill before treatment, with a reduced increase at the end of training period (24\ub121 vs 12\ub110 pg/mL; p<0.0005); a reduction of end-diastolic diameter of left ventricle at rest (48\ub14 mm vs 50\ub15 mm; p<0.05). The ejection fraction did not changed, while heart rate reduced after training (66\ub19 bpm vs 71\ub112 bpm; p<0.05). Conclusions: this study documented an improvement of hemodynamic and cardiac performance in response of physical training in peripheral arterial disease patients not affected by cardiac disease. Further trials will be necessary to evaluate the use of NTproBNP as a marker of good response to physical training in these patients

Supervised training improves endothelial function measured during induced ischemia in peripheral arterial disease.

Introduction: favorable effect of training on cardiovascular pathology is well documented in literature. Mechanisms evoked are the following: increased NO availability for reduction of oxidative stress, inflammation decrease, improvement of glucidic and lipidic metabolism, resetting of neuro-endocrine balance (1). These mechanism are also involved in the improvement of patients with peripheral arterial disease (PAD) treated with training. PAD is a model of inducible ischemia, in fact claudication is a condition in which ischemia/reperfusion phenomenon is present when walking is conducted till maximum pain (2). This phenomenon may produce a great amount of radical oxygen species with possible consequence on endothelium function. Xanthine oxidase is one of the most relevant enzyme involved in this process. Different types of training are proposed for PAD patients and there is not a consensus whether the ischemic pain should be reached during exercise. So we aimed to verify if maximal treadmill test (till pain) causes endothelial dysfunction, if oxidative stress is acutely aroused and if xanthine oxidase is involved. Therefore we aimed to verify if a training performed under the onset of ischemic pain can improve endothelial function ether at rest and after maximum tolerated exercise. Patients and methods: we enrolled 20 patients with PAD (16 males, 4 females, aged 65-77). Endothelium dependent dilation (EDD) was measured at humeral artery by ultrasound method, before and after maximal treadmill test (speed 3,2 km/h; slope 10%). We administered allopurinol 600 mg the day before and 600 mg 6 hours before a new treadmill test. Serum uric acid and lactate were determined throughout the study. Afterwards patients performed supervised training under pain onset for 20 days with physiotherapist overview. Every 7 days a new treadmill test was performed for updating training distance. At the end of the training period EDD was measured before and after a maximal treadmill test. Furthermore microcirculatory endothelium dependent dilation was measured at the skin of the forefoot by means of laser-Doppler (LD) after iontophoretic acetylcholine administration. Results: maximal treadmill test acutely reduced EDD (6,1\uf0b10,7 vs 9,2\uf0b10,9 %; p<0,05;). Allopurinol improved EDD (10,1\uf0b10,3 vs 9,4\uf0b10,6 %; p<0,05) with a reduced fall after maximal test (delta decrease -21,3\uf0b12,2 vs \u201333,2\uf0b11,2%; p<0,05). Training increased pain free walking distance (131\uf0b112 vs 66,6\uf0b121 m; p<0,05) and absolute walking distance (275\uf0b115 vs 125,8\uf0b140 m; p<0,05). EDD improved after training period (11,3\uf0b10,7 vs 9,2\uf0b10,9; p<0,05). The fall in EDD, observed during maximal treadmill test at the end of training period, was smaller than the one measured before training (delta decrease -15,5\uf0b12,4 vs \u201333,2\uf0b11,2%; p<0,005). Microcirculatory endothelium dependent dilation measured with LD increased after training (table). Table: microcirculatory flux with LD after iontophoretic acetylcholine. Acetylcholine 0,10 mA 10 s 20 s 40 s T 0 (% incr) 35\uf0b19 70\uf0b115 120\uf0b115 T 20 (%incr) 147\uf0b138* 182\uf0b122* 470\uf0b154* (*p<0.005 T20 vs T0) Conclusions: we demonstrate that walking through maximal pain causes impairment of EDD, this is caused by oxidative stress and can be reduced by inhibition of xanthine oxidase. Aerobic training improves EDD and microcirculatory endothelial function, furthermore training reduces the drop of EDD during maximal exercise and increased oxidative stress. As a consequence these results suggest the training should be performed under the maximal pain. References 1. Brendle DC, Joseph LJ, Corretti MC, Gardner AW, Katzel LI. Effects of exercise rehabilitation on endothelial reactivity in older patients with peripheral arterial disease. Am J Cardiol 2001;87:324-9. 2. Andreozzi GM, Leone A, Laudani R, Deinite G, Martini R. Acute impairment of the endothelial function by maximal treadmill exercise in patients with intermittent claudication, and its improvement after supervised physical training. Int Angiol. 2007; 26:12-7

CXCL12/SDF-1 from perisynaptic Schwann cells promotes regeneration of injured motor axonterminals

The neuromuscular junction has retained through evolution the capacity to regenerate after damage, but little is known on the inter-cellular signals involved in its functional recovery from trauma, autoimmune attacks, or neurotoxins. We report here that CXCL12, also abbreviated as stromal-derived factor-1 (SDF-1), is produced specifically by perisynaptic Schwann cells following motor axon terminal degeneration induced by -latrotoxin. CXCL12 acts via binding to the neuronal CXCR4 receptor. A CXCL12-neutralizing antibody or a specific CXCR4 inhibitor strongly delays recovery from motor neuron degeneration invivo. Recombinant CXCL12 invivo accelerates neurotransmission rescue upon damage and very effectively stimulates the axon growth of spinal cord motor neurons invitro. These findings indicate that the CXCL12-CXCR4 axis plays an important role in the regeneration of the neuromuscular junction after motor axon injury. The present results have important implications in the effort to find therapeutics and protocols to improve recovery of function after different forms of motor axon terminal damage

Direct current measurements of the SPIDER beam: a comparison to existing beam diagnostics

For negative ion beam sources there are several methods of measuring the accelerated beam current, most commonly electrical measurements at the power supply and calorimetric measurements. On SPIDER, the ITER Heating Neutral Beam full-scale beam source prototype, electrical measurements at the acceleration grid power supply (AGPS) are complemented by polarizing the diagnostic calorimeter STRIKE to provide an additional electrical measurement of the accelerated current. This is in addition to the calorimetric measurements provided by STRIKE. These diagnostics give differing measurements of the beam current. Exploiting the reduced number of open apertures on SPIDER a new beam diagnostic has been installed to measure the individual beamlet currents directly. The so called Beamlet Current Monitor (BCM) has been used to measure the current of five beamlets during the most recent SPIDER campaign. This work compares the BCM current to the electrical measurements at the AGPS and STRIKE. The average BCM current agrees well with the STRIKE electrical measurements, indicating that the AGPS overestimates the beam current. The individual beamlets are compared to the STRIKE calorimetric measurements, showing similar current trends with the source parameters