800 research outputs found
The OPERA magnetic spectrometer
The OPERA neutrino oscillation experiment foresees the construction of two
magnetized iron spectrometers located after the lead-nuclear emulsion targets.
The magnet is made up of two vertical walls of rectangular cross section
connected by return yokes. The particle trajectories are measured by high
precision drift tubes located before and after the arms of the magnet.
Moreover, the magnet steel is instrumented with Resistive Plate Chambers that
ease pattern recognition and allow a calorimetric measurement of the hadronic
showers. In this paper we review the construction of the spectrometers. In
particular, we describe the results obtained from the magnet and RPC prototypes
and the installation of the final apparatus at the Gran Sasso laboratories. We
discuss the mechanical and magnetic properties of the steel and the techniques
employed to calibrate the field in the bulk of the magnet. Moreover, results of
the tests and issues concerning the mass production of the Resistive Plate
Chambers are reported. Finally, the expected physics performance of the
detector is described; estimates rely on numerical simulations and the outcome
of the tests described above.Comment: 6 pages, 10 figures, presented at the 2003 IEEE-NSS conference,
Portland, OR, USA, October 20-24, 200
SO2 and ash plume retrievals using MSG-SEVIRI measurements. Test case: 24 November 2006 Mt. Etna eruption.
In this work the Thermal InfraRed (TIR) measurements of the Spin Enhanced Visible and Infrared Imager (SEVIRI) on board the Meteosat Second Generation (MSG) geosyncronous satellite, have been used to estimate the daily evolution of the SO2 columnar abundance and ash plume optical thickness, particle effective radius and total mass of Mt. Etna volcanic plume. As test case the 24 November 2006 eruption has been considered. SEVIRI is an optical imaging radiometer characterized by 12 spectral channels, a high temporal resolution (one image every 15 minutes) and a 9 km2 footprint. The instrument’s spectral range includes the 8.7 mm band (channel 7) and the10.8 and 12.0 mm split window bands (channels 9 and 10) used respectively for SO2 retrieval and volcanic ash detection and retrievals. The SO2 columnar abundance is estimated by means of a Look-Up Table (LUT) least squares fit procedure applied to channel 7 while the ash detection and retrievals are carried out by using the Brightness Temperature Difference algorithm applied to channels 9 and 10. All the simulations needed for the retrievals have been realized using the WMO Trapani meteo station atmospheric profiles and MODTRAN 4 radiative transfer model. The SEVIRI volcanic plume SO2 and ash retrieval has been compared with the results obtained by processing the data collected during the same eruption by the MODIS sensor on board of Aqua and Terra satellites. Results show the ability of SEVIRI to recognize and estimate the daily trend of SO2 and ash in an eruptive plume; for the 24 November 2006 eruption, the SO2 and ash emissions start at about 4 am and 9 am respectively and terminate simultaneously at about 3 pm. The comparison between SEVIRI and MODIS retrievals indicates a good agreement
Dimethyl-2-oxoglutarate improves redox balance and mitochondrial function in muscle pericytes of individuals with diabetes mellitus
Aims/hypothesis Treatment of vascular complications of diabetes remains inadequate. We reported that muscle pericytes (MPs) from limb muscles of vascular patients with diabetes mellitus display elevated levels of oxidative stress causing a dysfunctional phenotype. Here, we investigated whether treatment with dimethyl-2-oxoglutarate (DM-2OG), a tricarboxylic acid cycle metab- olite with antioxidant properties, can restore a healthy metabolic and functional phenotype.
Methods MPs were isolated from limb muscles of diabetes patients with vascular disease (D-MPs) and from non-diabetic control participants (ND-MPs). Metabolic status was assessed in untreated and DM-2OG-treated (1 mmol/l) cells using an extracellular flux analyser and anion-exchange chromatography–mass spectrometry (IC-MS/MS). Redox status was measured using commercial kits and IC-MS/MS, with antioxidant and metabolic enzyme expression assessed by quanti- tative RT-PCR and western blotting. Myogenic differentiation and proliferation and pericyte–endothelial interaction were assessed as functional readouts.
Results D-MPs showed mitochondrial dysfunction, suppressed glycolytic activity and reduced reactive oxygen species- buffering capacity, but no suppression of antioxidant systems when compared with ND-MP controls. DM-2OG supple- mentation improved redox balance and mitochondrial function, without affecting glycolysis or antioxidant systems. Nonetheless, this was not enough for treated D-MPs to regain the level of proliferation and myogenic differentiation of ND-MPs. Interestingly, DM-2OG exerted a positive effect on pericyte–endothelial cell interaction in the co-culture angiogenesis assay, independent of the diabetic status.
Conclusions/interpretation These novel findings support the concept of using DM-2OG supplementation to improve pericyte redox balance and mitochondrial function, while concurrently allowing for enhanced pericyte–endothelial crosstalk. Such effects may help to prevent or slow down vasculopathy in skeletal muscles of people with diabetes
Corrigendum to: “The genetics of exceptional longevity identifies new druggable targets for vascular protection and repair” [Pharmacol. Res. 114 (December) (2016) 169–174. doi: 10.1016/j.phrs.2016.10.028. Epub 2016 Nov 3]
The genetics of exceptional longevity identifies new druggable targets forvascular protection and repair
Therapeutic angiogenesis is a relatively new medical strategy in the field of cardiovascular diseases. The underpinning concept is that angiogenic growth factors or proangiogenic cells could be exploited therapeutically in cardiovascular patients to enhance native revascularization responses to an ischemic insult, thereby accelerating tissue healing. The initial enthusiasm generated by preclinical studies has been tempered by the modest success of clinical trials assessing therapeutic angiogenesis. Similarly, proangiogenic cell therapy has so far not maintained the original promises. Intriguingly, the current trend is to consider regeneration as a prerogative of the youngest organism. Consequentially, the embryonic and foetal models are attracting much attention for clinical translation into corrective modalities in the adulthood. Scientists seem to undervalue the lesson from Mother Nature, e.g. all humans are born young but very few achieve the goal of an exceptional healthy longevity. Either natural experimentation is driven by a supreme intelligence or stochastic phenomena, one has to accept the evidence that healthy longevity is the fruit of an evolutionary process lasting million years. It is therefore extremely likely that results of this natural experimentation are more reliable and translatable than the intensive, but very short human investigation on mechanisms governing repair and regeneration. With this preamble in mind, here we propose to shift the focus from the very beginning to the very end of human life and thus capture the secret of prolonged health span to improve well-being in the adulthood
Riflettanza di superfici vulcaniche:la campagna 2003 sul Monte Etna
The results obtained in Mt. Etna spectroradiometric field survey of June 2003 are presented and discussed. The goal of the survey was the analysis of the reflectance properties of the young pyroclastic deposits produced after the effusive activity of 2002-2003 and of the older lava flows. To achieve this goal, a template was created in order to organize the field data collected in a number of selected sites characterised by different surface materials. The results show that reflectance of pyroclastic flows is always very low and constant, besides grain size and composition of the flow. Pahoehoe units show higher reflectance values, even though the spectral characterisation of the older lava flows must take into account weathering
products and vegetation coverage
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