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Revising the retrieval technique of a long-term stratospheric HNO3 data set: from a constrained matrix inversion to the optimal estimation algorithm
I. Fiorucci, G. Muscari,R. L. de Zafra
Annales Geophysicae (ANGEO) , 2011,
Abstract: The Ground-Based Millimeter-wave Spectrometer (GBMS) was designed and built at the State University of New York at Stony Brook in the early 1990s and since then has carried out many measurement campaigns of stratospheric O3, HNO3, CO and N2O at polar and mid-latitudes. Its HNO3 data set shed light on HNO3 annual cycles over the Antarctic continent and contributed to the validation of both generations of the satellite-based JPL Microwave Limb Sounder (MLS). Following the increasing need for long-term data sets of stratospheric constituents, we resolved to establish a long-term GMBS observation site at the Arctic station of Thule (76.5° N, 68.8° W), Greenland, beginning in January 2009, in order to track the long- and short-term interactions between the changing climate and the seasonal processes tied to the ozone depletion phenomenon. Furthermore, we updated the retrieval algorithm adapting the Optimal Estimation (OE) method to GBMS spectral data in order to conform to the standard of the Network for the Detection of Atmospheric Composition Change (NDACC) microwave group, and to provide our retrievals with a set of averaging kernels that allow more straightforward comparisons with other data sets. The new OE algorithm was applied to GBMS HNO3 data sets from 1993 South Pole observations to date, in order to produce HNO3 version 2 (v2) profiles. A sample of results obtained at Antarctic latitudes in fall and winter and at mid-latitudes is shown here. In most conditions, v2 inversions show a sensitivity (i.e., sum of column elements of the averaging kernel matrix) of 100 ± 20 % from 20 to 45 km altitude, with somewhat worse (better) sensitivity in the Antarctic winter lower (upper) stratosphere. The 1σ uncertainty on HNO3 v2 mixing ratio vertical profiles depends on altitude and is estimated at ~15 % or 0.3 ppbv, whichever is larger. Comparisons of v2 with former (v1) GBMS HNO3 vertical profiles, obtained employing the constrained matrix inversion method, show that v1 and v2 profiles are overall consistent. The main difference is at the HNO3 mixing ratio maximum in the 20–25 km altitude range, which is smaller in v2 than v1 profiles by up to 2 ppbv at mid-latitudes and during the Antarctic fall. This difference suggests a better agreement of GBMS HNO3 v2 profiles with both UARS/ and EOS Aura/MLS HNO3 data than previous v1 profiles.
On the cryogenic removal of NOy from the Antarctic polar stratosphere
R. L. de Zafra,G. Muscari,S. Smyshlyaev
Annals of Geophysics , 2003, DOI: 10.4401/ag-3402
Abstract: We review current knowledge about the annual cycle of transport of nitrogen oxides to, and removal from, the polar stratosphere, with particular attention to Antarctica where the annual winter denitrifi cation process is both regular in occurrence and severe in effect. Evidence for a large downward fl ux of NOy from the mesosphere to the stratosphere, fi rst seen briefl y in the Limb Infrared Monitor of the Stratosphere (LIMS) data from the Arctic winter of 1978-1979, has been found during the 1990s in both satellite and ground-based observations, though this still seems to be omitted from many atmospheric models. When incorporated in the Stony Brook- St. Petersburg two dimensional (2D) transport and chemistry model, more realistic treatment of the NOy fl ux, along with sulfate transport from the mesosphere, sulfate aerosol formation where temperature is favorable, and the inclusion of a simple ion-cluster reaction, leads to good agreement with observed HNO3 formation in the mid-winter middle to upper stratosphere. To further emphasize the importance of large fl uxes of thermospheric and mesospheric NOy into the polar stratosphere, we have used observations, supplemented with model calculations, to defi ne new altitude dependent correlation curves between N2O and NOy. These are more suitable than those previously used in the literature to represent conditions within the Antarctic vortex region prior to and during denitrifi cation by Polar Stratospheric Cloud (PSC) particles. Our NOy -N2O curves lead to a 40% increase in the average amount of NOy removed during the Antarctic winter with respect to estimates calculated using NOy-N2O curves from the Atmospheric Trace Molecule Spectroscopy (ATMOS)/ATLAS-3 data set.
Millimeter wave spectroscopic measurements of stratospheric and mesospheric constituents over the Italian Alps: stratospheric ozone
G. Muscari,C. Cesaroni,C. Bianchi,R. L. de Zafra
Annals of Geophysics , 2007, DOI: 10.4401/ag-4429
Abstract: Measurements of rotational lines emitted by middle atmospheric trace gases have been carried out from the Alpine station of Testa Grigia (45.9°N, 7.7°E, elev. 3500 m) by means of a Ground-Based Millimeter-wave Spectrometer (GBMS). Observations of species such as O3, HNO3, CO, N2O, HCN, and HDO took place during 4 winter periods, from February 2004 to March 2007, for a total of 116 days of measurements grouped in about 18 field campaigns. By studying the pressure-broadened shape of emission lines the vertical distribution of the observed constituents is retrieved within an altitude range of ?17-75 km, constrained by the 600 MHz pass band and the 65 kHz spectral resolution of the back-end spectrometer. This work discusses the behavior of stratospheric O3 during the entire period of operation at Testa Grigia. Mid-latitude O3 columnar content as estimated using GBMS measurements can vary by large amounts over a period of very few days, with the largest variations observed in December 2005, February 2006, and March 2006, confirming that the northern winter of 2005-2006 was characterized by a particularly intense planetary wave activity. The largest rapid variation from maximum to minimum O3 column values over Testa Grigia took place in December 2006 and reached a relative value of 72% with respect to the average column content for that period. During most GBMS observation times much of the variability is concentrated in the column below 20 km, with tropospheric weather systems and advection of tropical tropospheric air into the lower stratosphere over Testa Grigia having a large impact on the observed variations in column contents. Nonetheless, a wide variability is also found in middle stratospheric GBMS O3 measurements, as expected for mid-latitude ozone. We find that O3 mixing ratios at ?32 km are very well correlated with the solar illumination experienced by air masses over the previous ?15 days, showing that already at 32 km altitude ozone photochemistry dominates over transport processes. The correlation of lower stratospheric ozone concentrations with potential vorticity as an indicator of transport is instead not as clear-cut, due to very complex mixing processes that characterize stratospheric air at mid-latitudes. Correlations of O3 over Testa Grigia with stratospheric tracers such as N2O and HCN, also observed by means of the GBMS, are planned for the future, in order to better characterize lower stratospheric dynamics and therefore lower stratospheric ozone concentrations at mid-latitudes.
Ground-based stratospheric O3 and HNO3 measurements at Thule, Greenland: an intercomparison with Aura MLS observations
I. Fiorucci,G. Muscari,L. Froidevaux,M. L. Santee
Atmospheric Measurement Techniques Discussions , 2013, DOI: 10.5194/amtd-6-2979-2013
Abstract: In response to the need for improving our understanding of the evolution and the interannual variability of the winter Arctic stratosphere, in January 2009 a ground-based millimeter-wave spectrometer (GBMS) was installed at the Network for the Detection of Atmospheric Composition Change (NDACC) site in Thule (76.5° N, 68.8° W), Greenland. In this work, stratospheric GBMS O3 and HNO3 vertical profiles obtained from Thule during winters 2010 (HNO3 only), 2011 and 2012 are characterized and intercompared with co-located Aura MLS measurements. Using a recently developed algorithm based on Optimal Estimation, we find that the GBMS O3 retrievals show good sensitivity (> 80%) to atmospheric variations between ~ 17 and ~ 50 km, where their 1σ uncertainty is estimated to be the larger of ~ 11% or 0.2 ppmv. Similarly, HNO3 profiles can be considered for scientific use between ~ 17 and ~ 45 km altitude, with a 1σ uncertainty that amounts to the larger of 15% or 0.2 ppbv. Comparisons with Aura MLS version 3.3 observations show that, on average, GBMS O3 mixing ratios are biased low with respect to MLS throughout the stratosphere, with differences ranging between ~ 0.3 ppmv (8%) and 0.9 ppmv (18%) in the 17–50 km vertical range. GBMS HNO3 values display instead a high bias with respect to MLS up to 26 km, reaching a maximum of ~ 1 ppbv (10%) near the mixing ratio profile peak. O3 and HNO3 values from the two data sets prove to be well correlated at all altitudes, although their correlations worsen at the lower end of the altitude ranges considered. Column contents of GBMS and MLS O3 (from 20 km upwards) and HNO3 (from 17 km upwards) correlate very well and indicate that GBMS measurements can provide valuable estimates of column interannual and seasonal variations for these compounds.
Development of a 22 GHz ground-based spectrometer for middle atmospheric water vapour monitoring
Pietro Paolo Bertagnolio,Giovanni Muscari,James Baskaradas
European Journal of Remote Sensing , 2012,
Abstract: The water Vapour Emission SPectrometer for Antarctica at 22 GHz (VESPA-22) has been designed for long-term middle atmospheric climate change monitoring and satellite data validation. It observes the water vapour spectral line at 22.235 GHz using the balanced beam-switching technique. The receiver antenna has been characterized, showing an HPBW of 3.5° and a sidelobe level 40 dB below the main lobe. The receiver front-end has a total gain of 105 dB and a LNA noise temperature of 125 K. A FFT spectrometer (bandwidth 1 GHz, resolution 63 kHz) will be used as back-end, allowing the retrieval of H2O concentration profiles in the 20 to 80 km altitude range. The control I/O interface is based on reconfigurable hardware (USB-CPLD).
Comparison between Culture Conditions Improving Growth and Differentiation of Blood and Bone Marrow Cells Committed to the Endothelial Cell Lineage
Muscari Claudio,Gamberini Chiara,Basile Ilaria,Bonafé Francesca
Biological Procedures Online , 2010,
Abstract: The aim of this study was to compare different cell sources and culture conditions to obtain endothelial progenitor cells (EPCs) with predictable antigen pattern, proliferation potential and in vitro vasculogenesis. Pig mononuclear cells were isolated from blood (PBMCs) and bone marrow (BMMCs). Mesenchymal stem cells (MSCs) were also derived from pig bone marrow. Cells were cultured on fibronectin in the presence of a high concentration of VEGF and low IGF-1 and FGF-2 levels, or on gelatin with a lower amount of VEGF and higher IGF-1 and FGF-2 concentrations. Endothelial commitment was relieved in almost all PBMCs and BMMCs irrespective of the protocol used, whilst MSCs did not express a reliable pattern of EPC markers under these conditions. BMMCs were more prone to expand on gelatin and showed a better viability than PBMCs. Moreover, about 90% of the BMMCs pre-cultured on gelatin could adhere to a hyaluronan-based scaffold and proliferate on it up to 3 days. Pre-treatment of BMMCs on fibronectin generated well-shaped tubular structures on Matrigel, whilst BMMCs exposed to the gelatin culture condition were less prone to form vessel-like structures. MSCs formed rough tubule-like structures, irrespective of the differentiating condition used. In a relative short time, pig BMMCs could be expanded on gelatin better than PBMCs, in the presence of a low amount of VEGF. BMMCs could better specialize for capillary formation in the presence of fibronectin and an elevated concentration of VEGF, whilst pig MSCs anyway showed a limited capability to differentiate into the endothelial cell lineage.
Recurrent ischemic strokes in a young celiac woman with MTHFR gene mutation
Elisa Fabbri,Lisa Rustignoli,Antonio Muscari,Giovanni M Puddu
World Journal of Gastroenterology , 2012, DOI: 10.3748/wjg.v18.i26.3472
Abstract: Celiac disease (CD) is frequently associated with neurological disorders, but very few reports concern the association with ischemic stroke. A 26-year-old woman affected by CD with secondary amenorrhea, carrier of a homozygous 5,10-methylenetetrahydrofolate reductase mutation with hyperhomocysteinemia, was affected by two occipital ischemic strokes within a period of 5 mo. At the time of the second stroke, while she was being treated with folic acid, acetylsalicylic acid and a gluten-free diet, she had left hemianopsia, left hemiparesthesias, and gait imbalance. Brain magnetic resonance imaging showed a subacute right occipital ischemic lesion, which was extended to the dorsal region of the right thalamus and the ipsilateral thalamo-capsular junction. Antitransglutaminase and deamidated gliadin peptide antibodies were no longer present, while antinuclear antibodies, antineuronal antibodies and immune circulating complexes were only slightly elevated. Since the patient was taking folic acid, her homocysteine levels were almost normal and apparently not sufficient alone to explain the clinical event. A conventional cerebral angiography showed no signs of vasculitis. Finally, rare causes of occipital stroke in young patients, such as Fabry’s disease and mitochondrial myopathy, encephalomyopathy, lactic acidosis and stroke-like symptoms, were also excluded by appropriate tests. Thus, the most probable cause for the recurrent strokes in this young woman remained CD, although the mechanisms involved are still unknown. The two main hypotheses concern malabsorption (with consequent deficiency of vitamins known to exert neurotrophic and neuroprotective effects) and immune-mediated mechanisms. CD should be kept in mind in the differential diagnosis of ischemic stroke in young patients.
Carotid lesions in outpatients with nonalcoholic fatty liver disease
Stefano Ramilli, Stefano Pretolani, Antonio Muscari, Barbara Pacelli, Vincenzo Arienti
World Journal of Gastroenterology , 2009,
Abstract: AIM: To ascertain whether carotid lesions are more prevalent in outpatients with incidental findings of nonalcoholic fatty liver disease (NAFLD) at abdominal ultrasound (US).METHODS: One hundred and fifty-four consecutive outpatients (age range 24-90 years, both sexes) referred by general practitioners for abdominal US, and drinking less than 20 g alcohol/day, underwent carotid US for an assessment of carotid intima-media thickness (c-IMT) and carotid plaque prevalence. Hepatic steatosis, visceral fat thickness and subcutaneous fat thickness were also assessed at ultrasonography.RESULTS: Higher c-IMT values were found in the presence of NAFLD (90 patients), even after adjustment for indices of general and abdominal obesity and for the principal cardiovascular risk factors (0.84 ± 0.10 mm vs 0.71 ± 0.10 mm, P < 0.001). The prevalence of carotid plaques was 57.8% in the patients with NAFLD vs 37.5% in the patients without this condition (P = 0.02). The adjusted relative risk of having carotid plaques for patients with NAFLD was 1.85 (95% CI: 1.33-2.57, P < 0.001).CONCLUSION: An incidental finding of hepatic steatosis may suggest the presence of silent carotid atherosclerotic lesions.
Strategies Affording Prevascularized Cell-Based Constructs for Myocardial Tissue Engineering
Claudio Muscari,Emanuele Giordano,Francesca Bonafè,Marco Govoni,Carlo Guarnieri
Stem Cells International , 2014, DOI: 10.1155/2014/434169
Abstract: The production of a functional cardiac tissue to be transplanted in the injured area of the infarcted myocardium represents a challenge for regenerative medicine. Most cell-based grafts are unviable because of inadequate perfusion; therefore, prevascularization might be a suitable approach for myocardial tissue engineering. To this aim, cells with a differentiation potential towards vascular and cardiac muscle phenotypes have been cocultured in 2D or 3D appropriate scaffolds. In addition to these basic approaches, more sophisticated strategies have been followed employing mixed-cell sheets, microvascular modules, and inosculation from vascular explants. Technologies exerting spatial control of vascular cells, such as topographical surface roughening and ordered patterning, represent other ways to drive scaffold vascularization. Finally, microfluidic devices and bioreactors exerting mechanical stress have also been employed for high-throughput scaling-up production in order to accelerate muscle differentiation and speeding the endothelialization process. Future research should address issues such as how to optimize cells, biomaterials, and biochemical components to improve the vascular integration of the construct within the cardiac wall, satisfying the metabolic and functional needs of the myocardial tissue. 1. Introduction One of the most ambitious objectives for cardiac tissue engineering aimed at repairing an infarcted cardiac region is the production of a stem cell-based functional tissue that can be fully integrated within native myocardium [1–3]. However, although basic researches and preclinical studies have paved the way for translational applications of cell therapy for cardiac repair, so far clinical trials have failed to reproduce relevant positive results [4]. Ongoing efforts are thus needed to optimize most steps involved with a therapeutic approach to myocardial infarction and failure using stem cells, including cell preparations, cell delivery techniques, and cell survival [5]. Up to now, stem cells transplanted alone or carried onboard of polymeric devices have shown a short survival in the heart because these grafts were not adequately perfused by coronary vessels [6, 7]; hence, most grafted cells rapidly die or migrate near the border zone of the infarcted area, close to the coronary vessels [8]. To provide sufficient oxygen and nutrients for survival, metabolically active grafts should be supplied by a vascular network reaching cardiomyocytes within a 150–200？μm distance [9]. Therefore, the laboratory realization of prevascularized
Complete Disaggregation of MCF-7-derived Breast Tumour Spheroids with Very Low Concentrations of α-Mangostin Loaded in CD44 Thioaptamer-tagged Nanoparticles
Carlo Guarnieri,Claudia Pazzini,Claudio Muscari,Francesca Bonafè,Silvia Marchionni
- , 2019, DOI: 10.7150/ijms.28135
Abstract: Background: α-Mangostin (αMG) is a natural substance that exerts a wide range of antitumor effects. Recently, we described that free αMG was able to dissociate multicellular tumour spheroids (MCTSs) generated from breast carcinoma cells and to reduce their cellular viability and motility. Here, αMG was encapsulated into lipidic nanoparticles (NPs), conjugated or not to a CD44 thioaptamer, and the anticancer action evaluated against MCF-7 breast MCTSs.
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