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Search Results: 1 - 10 of 14076 matches for " Andrea Marchegiani "
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Further evidence to support a role of oxidative stress and inflammation in myocardial infarction
Francesca Marchegiani
Anadolu Kardiyoloji Dergisi , 2013,
Comparative Oral Absorption of Different Citicoline and Homotaurine Formulations: A Single-Dose, Two-Period Crossover Trial in the Dog  [PDF]
Andrea Marchegiani, Ferdinando Nicoletti, Maria Rosaria Romano, Decio Capobianco, Ciro Costagliola, Carlotta Marini, Giuseppe Lubrano Lavadera, Roberto Ciccocioppo, Andrea Spaterna
Journal of Biomedical Science and Engineering (JBiSE) , 2019, DOI: 10.4236/jbise.2019.127028
Abstract: Background: Citicoline and homotaurine are compounds with a potent neuroprotective activity and they have been administered for many years in the treatment of numerous neurodegenerative and ophthalmological diseases, including glaucoma. Initially available only as liquid form, through parenteral route, nowadays citicoline can be administered also as tablet but no data on bioavailability of these different forms are available. In the present study, pharmacokinetics of citicoline in tablet versus vials, each at the therapeutic dose of 500 mg, in addition to 50 mg of homotaurine was investigated. Materials and methods: Ten mixed breed dogs received a single dose of 50 mg oral homotaurine and 500 mg citicoline in tablet and vials with the same dose were administered after a seven days wash-out period. Parameters assessed for citicoline metabolites (cytidine, uridine and choline) were AUC0t, Cmax and Tmax. Results: Citicoline bioavailability appeared to be slightly higher for the tablet compared to the vial formulation. Cytidine is equivalent in absorption dynamics both for tablet and liquid form; uridine for tablet reaches its maximum and is reabsorbed more quickly while choline for the liquid form reaches the maximum first and is reabsorbed more quickly. Conclusions: Citicoline in tablet and liquid formulation have pharmacokinetic properties leading to a very similar bioavailability.
The valorisation of abandoned railway yards. The case of Milan
Elena Mussinelli,Cristina Marchegiani
Techne : Journal of Technology for Architecture and Environment , 2012,
Abstract: Milan’s urban growth was heavily influenced by the structure of the rail network for transporting goods and people. The great railway yards that used to service the industrial system have now lost their raison d'être after the relocation of industrial plants and the tertiary sector dynamics took over the city. These have become large abandoned brownfields or soon to be abandoned, totaling over 1,300,000 square meters, located mainly along the urban belt surrounding the city walls, often in densely built environments. Since 2005 these areas were the subject of several agreements between the City of Milan, State Railways SpA (FS) and the Lombardy Region, to examine various scenarios and the feasibility of their conversion, as confirmed in the draft of the new Territorial Government Plan (PGT), which identifies the Areas of Urban Transformation. Scenarios and assumptions that, in the current revision of the PGT, must approach the strategic role of this rich heritage from an environmental regeneration and valorization perspective extended to urban and metropolitan scales.
On the ability of spectroscopic SZ effect measurements to determine the temperature structure of galaxy clusters
S. Colafrancesco,P. Marchegiani
Physics , 2009, DOI: 10.1051/0004-6361/200913115
Abstract: (abridged) We explore in this paper the ability of spatially resolved spectroscopic measurements of the SZ effect (SZE) to determine the temperature profile of galaxy clusters. We derive a general formalism for the thermal SZE in galaxy clusters with a non-uniform temperature profile that can be applied to both cool-core clusters and non-cool core cluster with an isothermal or non-isothermal temperature structure. We derive an inversion technique through which the electron distribution function can be extracted from spectroscopic SZE observations over a wide frequency range. We study the fitting procedure to extract the cluster temperature from a set of simulated spatially resolved spectroscopic SZE observations in different bands of the spectrum, from 100 to 450 GHz. The results of our analysis for three different cluster prototypes (A2199 with a low-temperature cool core, Perseus with a relatively high-temperature cool core, Ophiuchus with an isothermal temperature distribution) provide both the required precision of the SZE observations and the optimal frequency bands for a determination of the cluster temperature similar or better than that obtainable from X-ray observations. The precision of SZE-derived temperature is also discussed for the outer regions of clusters. We also study the possibility to extract, from our method, the parameters characterizing the non-thermal SZE spectrum of the relativistic plasma contained in the lobes of radio galaxies as well as the spectrum of relativistic electrons co-spatially distributed with the thermal plasma in clusters with non-thermal phenomena. We find that the next generation SZE experiments with spectroscopic capabilities can provide precise temperature distribution measurements (...)
On the ICS interpretation of the Hard X-Ray Excesses in Galaxy Clusters: the case of Ophiuchus
S. Colafrancesco,P. Marchegiani
Physics , 2009, DOI: 10.1051/0004-6361/200911843
Abstract: (Abridged) High-E electrons produce Hard X-Ray (HXR) emission in galaxy clusters by via Inverse Compton Scattering (ICS) of CMB photons. We derive the ICS HXR emission of Ophiuchus under various scenarios: primary cosmic ray model, secondary cosmic rays model and neutralino DM annihilation scenario. We further discuss the predictions of the Warming Ray model for the cluster atmosphere. Under the assumption to fit the observed HXR emission, we find that the high-E electrons induce various consequences on the cluster atmosphere: i) primary electrons can be marginally consistent with the data provided that their spectrum is cutoff at E~30(90) MeV for spectral index of 3.5 (4.4); ii) secondary electron models from pp collisions are inconsistent with gamma-ray limits, cosmic ray protons produce too much heating of the IC gas and their pressure at the cluster center largely exceeds the thermal one; iii) secondary electron models from DM annihilation are inconsistent with gamma-ray and radio limits and electrons produce too much heating of the IC gas at the cluster center, unless the neutralino annihilation cross section is much lower than the proposed value. We conclude that ICS by secondary electrons from both neutralino DM annihilation and pp collisions cannot be the mechanism responsible for the HXR excess emission; primary electrons are still a marginally viable solution provided that their spectrum has a low-energy cutoff at E~30-90 MeV. The WR model offers, so far, the best description of the cluster in terms of temperature distribution, heating, pressure and spectral energy distribution. Fermi observations of Ophiuchus will set further constraints to this model.
The energetics of giant radio galaxy lobes from inverse Compton scattering observations
S. Colafrancesco,P. Marchegiani
Physics , 2011, DOI: 10.1051/0004-6361/201117505
Abstract: Giant radio galaxy (GRG) lobes are excellent laboratories to study the evolution of the particle and B-field energetics. However, these results are based on assumptions of the shape and extension of the GRG lobe electron spectrum. We re-examine the energetics of GRG lobes as derived by inverse Compton scattering of CMB photons (ICS-CMB) by relativistic electrons in RG lobes to assess the physical conditions of RG lobes, their energetics and their radiation regime. We consider the GRG DA 240 recently observed by Suzaku as a reference case and we also discuss other RG lobes observed with Chandra and XMM. We model the spectral energy distribution of the DA 240 East lobe to get constraint on the shape and the extension of the electron spectrum in the lobe by using multi-frequency information from radio to gamma-rays. We use radio and X-ray data to constrain the shape and normalization of the electron spectrum and we then calculate the SZ effect expected in GRG lobes that is sensitive to the total electron energy density. We show that the electron energy density U_e derived form X-ray observations yields only a rough lower limit to its actual value and that most of the estimates of U_e based on X-ray measurements have to be increased even by a large factor by considering realistic estimates of the lower electron momentum p_1. This brings RG lobes away from the equipartition condition towards a particle-dominated and Compton power dominance regime. We use the distribution of RG lobes in the U_e/U_B vs. U_e/U_CMB plane as a further divide between different physical regimes of particle and field dominance, and radiation mechanism dominance in RG lobes. We conclude that the SZ effect produced by ICS-CMB mechanism observable in RG lobes provides reliable estimate of p_1 and U_e and is the best tool to determine the total energy density of RG lobes and to assess their physical regime.
Is the radio emission in the Bullet cluster due to Dark Matter annihilation?
P. Marchegiani,S. Colafrancesco
Physics , 2015, DOI: 10.1093/mnras/stv1377
Abstract: We study the complex structure of the Bullet cluster radio halo to determine the Dark Matter (DM) contribution to the emission observed in the different subhalos corresponding to the DM and baryonic dominated regions. We use different non-thermal models to study the different regions, and we compare our results with the available observations in the radio, X-ray and gamma-ray bands, and the Sunyaev-Zel'dovich (SZ) effect data. We find that the radio emission coming from the main DM subhalo can be produced by secondary electrons produced by DM annihilations. In this scenario there are however some open issues, like the difficulty to explain the observed flux at 8.8 GHz, the high value of the required annihilation cross section, and the lack of observed emission coming from the minor DM subhalo. We also find that part of the radio emission originated by DM annihilation could be associated with a slightly extended radio source present near the main DM subhalo. Regarding the baryonic subhalos, the radio measurements do not allow to discriminate between a primary or secondary origin of the electrons, while the SZ effect data point towards a primary origin for the non-thermal electrons in the Main Subcluster. We conclude that in order to better constrain the properties of the DM subhalos, it is important to perform detailed measurements of the radio emission in the regions where the DM halos have their peaks, and that the separation of the complex radio halo in different subhalos is a promising technique to understand the properties of each specific subhalo.
Probing photon decay with the Sunyaev-Zel'dovich effect
S. Colafrancesco,P. Marchegiani
Physics , 2013, DOI: 10.1051/0004-6361/201323100
Abstract: The fundamental properties of the photon have deep impact on the astrophysical processes that involve it, like the inverse Compton scattering of CMB photon by energetic electrons residing within galaxy cluster atmospheres, usually referred to as the Sunyaev-Zel'dovich effect (SZE). We calculate the combined constraints on the photon decay time and mass by studying the impact of the modified CMB spectrum, as recently calculated (Heeck 2013), on the SZE of galaxy clusters. We analyze the modifications of the SZE as produced by photon decay effects. We study in details the frequency regimes where these modifications are large and where the constraints derived from the SZE can be stronger with respect to those already obtained from the CMB spectrum. We show that the SZE can set limits on the photon decay time and mass, or on $E^* = \frac{t_0}{\tau_\gamma}m_\gamma c^2$, that are stronger than those obtained from the CMB: the main constraints come from the low frequency range $\nu \approx 10-50$ GHz where the modified SZE $\Delta I_{mod}$ is larger than the standard one $\Delta I$, with the difference $|(\Delta I_{mod} - \Delta I)|$ increasing with the frequency for increasing values of $E^*$; additional constraints can be set in the range $120 - 180$ GHz where there is an increase of the frequency position of the minimum of $\Delta I_{mod}$ with respect to the standard one with increasing values of $E^*$. We demonstrated that the effect of photon decay can be measured or constrained by the Square Kilometer Array in the optimal range $\approx 10-30$ GHz setting limits of $E^* \leq 1.4 \times 10^{-9}$ eV and $5 \times 10^{-10}$ eV for 30 and 260 hour integration for A2163, respectively. These limits are stronger than those obtained with the COBE-FIRAS spectral measurements of the CMB.
Marchegiani,Marina; Palamarczuk,Valeria; Reynoso,Alejandra;
Boletín del Museo Chileno de Arte Precolombino , 2009, DOI: 10.4067/S0718-68942009000100005
Abstract: through the study of a particular group of black on red late urns, we examine the issue of multifaceted intergroup relationships in border areas. the sample is composed of 43 vessels in which we noticed an interesting blend of santa maría and belén stylistic elements. through a stylistic and contextual analysis, we attempt to explain the social dynamics behind this combination. the urns are dated immediately prior to or contemporary with the presence of the inka in northwest argentina, up to the first spanish conquest of the area. using this case study, we will reflect on the dynamic of the inka expansion in the south-andean region, proposing that the transformation that resulted from the imperial expansion would have begun before the arrival of the representatives of tawantinsuyu.
Diagnóstico prenatal del pie bot
Masquijo,Julio Javier; Marchegiani,Silvio; Allende,Victoria;
Revista argentina de radiolog?-a , 2011,
Abstract: introduction. clubfoot is one of the most frequent congenital musculoskeletal anomalies. the use of ultrasound for prenatal detection of clubfoot has advanced rapidly in the last decade, but publications report a great variability in opinions regarding the effectiveness of the method, the association with other diseases and the need to perform amniocentesis analysis of the karyotype. objectives. to analyze the percentage of patients with prenatal diagnosis of clubfoot, evaluate mothers' opinion on this issue, and clarify some concepts by reviewing the literature available to date. methods. we retrospectively analyzed a group of 54 consecutive patients diagnosed with clubfoot treated from january 2008 to june 2010. we documented the number of ultrasounds performed during pregnancy, type of ultrasound (2d, 3d or 4d) and the gestational week at diagnosis. mothers were surveyed to ascertain their opinion with regard to prenatal diagnosis. results. an average of 3.2 ultrasounds was performed during pregnancy (r, 1-7). prenatal diagnosis was performed in 25% of cases (13/52 patients). diagnosis was performed in 7 cases with 2-d ultrasound in 4 with 3-d and in 2 with 4-d. diagnosis was performed on average at week 22 (r, 20- 28). no patient was diagnosed early, 12 were diagnosed late and 1 very late. conclusion. prenatal diagnosis gives parents the opportunity for psychological preparation and counseling regarding clubfoot. in our series, 90.4% supported prenatal diagnosis.
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