1,488 research outputs found
Carcinoma mucoepidermoide della base della lingua
Mucoepidermoid carcinoma (MEC) is the most common malignant, locally-invasive tumour of the salivary glands, and accounts for approximately 35% of all malignancies of the major and minor salivary gland. Minor salivary glands are scattered in different areas of the oral cavity such as palate, retromolar area, floor of the mouth, buccal mucosa, lips and tongue. MECs of tongue base are not common. We present a rare case of MEC localised at the tongue base in a 42-year-old Caucasian woman and discuss the histopathological types, management and review the literature. Adequate intra-oral excision was the treatment of choice in this case and in low-grade MEC. Prognosis of MEC is a function of the histological grade, adequacy of excision and clinical staging. © 2015, Pacini Editore s.r.l. All rights reserved
Reduced combustion mechanism for fire with light alcohols
The need for sustainable energy has incentivized the use of alternative fuels such as light alcohols. In this work, reduced chemistry mechanisms for the prediction of fires (pool fire, tank fire, and flash fire) for two primary alcohols—methanol and ethanol—were developed, aiming to integrate the detailed kinetic model into the computational fluid dynamics (CFD) model. The model accommodates either the pure reactants and products or other intermediates, including soot precursors (C2H2, C2H4, and C3H3 ), which were identified via sensitivity and reaction path analyses. The developed reduced mechanism was adopted to predict the burning behavior in a 3D domain and for the estimation of the product distribution. The agreement between the experimental data from the literature and estimations resulting from the analysis performed in this work demonstrates the successful application of this method for the integration of kinetic mechanisms and CFD models, opening to an accurate evaluation of safety scenarios and allowing for the proper design of storage and transportation systems involving light alcohols
On the prediction of the ignition delay time of bio-syngas
The growing energy demand and more stringent environmental regulations have raised concerns about the production and use of alternative fuels. Due to the potential application of the resulting gaseous streams in turbines as an energy source, slow pyrolysis of biomass including municipal waste have been extensively studied under various situations and atmospheric conditions. Nevertheless, the combustion characteristics of these complex mixtures and the chemical interactions between their constituent species are still not fully understood. Hence, the accuracy of commonly used empirical-based mixing rules for the estimation of the overall reactivity, such as laminar burning velocity and ignition delay time is inefficient. This work is addressed to the numerical prediction of the Ignition Delay Time, IDT, of bio-syngas mixtures at different fuel compositions, stoichiometries, temperature, and pressure, by means of a detailed kinetic model. A simplified tool for preliminary evaluation of the overall reactivity with respect to the above-mentioned conditions was proposed for these mixtures, as well, providing an effective feature for safety and management evaluations
Résolution numérique d'un déplacement diphasique, en milieu poreux en présence de gravité et de forces capillaires
résum
Improving Dark Energy Constraints with High Redshift Type Ia Supernovae from CANDELS and CLASH
Aims. We investigate the degree of improvement in dark energy constraints
that can be achieved by extending Type Ia Supernova (SN Ia) samples to
redshifts z > 1.5 with the Hubble Space Telescope (HST), particularly in the
ongoing CANDELS and CLASH multi-cycle treasury programs.
Methods. Using the popular CPL parametrization of the dark energy, w = w0
+wa(1-a), we generate mock SN Ia samples that can be projected out to higher
redshifts. The synthetic datasets thus generated are fitted to the CPL model,
and we evaluate the improvement that a high-z sample can add in terms of
ameliorating the statistical and systematic uncertainties on cosmological
parameters.
Results. In an optimistic but still very achievable scenario, we find that
extending the HST sample beyond CANDELS+CLASH to reach a total of 28 SN Ia at z
> 1.0 could improve the uncertainty in the wa parameter by up to 21%. The
corresponding improvement in the figure of merit (FoM) would be as high as 28%.
Finally, we consider the use of high-redshift SN Ia samples to detect
non-cosmological evolution in SN Ia luminosities with redshift, finding that
such tests could be undertaken by future spacebased infrared surveys using the
James Webb Space Telescope (JWST).Comment: 9 pages, 6 figures, accepted for publication on Astronomy &
Astrophysic
Surgical management of pleomorphic adenoma of parotid gland in elderly patients: Role of morphological features.
The neoplasms of the salivary glands account for 2% of head and neck tumors and the most common form is the Pleomorphic Adenoma (PA). Parotid gland is affected from 80% to 90% of cases. In elderly this tumors occurs mostly in females. These benign tumors are composed of epithelial and myoepithelial cells that are arranged with various morphological patterns and subtypes. The classification of these tumors is also based on the amount and nature of the stroma. In literature there is a almost complete consensus that, in the major salivary glands, PAs are enclosed by a layer of fibrous tissue often called "capsule" but there is disagreement about the form, extention and thickness of this layer. The treatment is surgical and there are two main different surgical approaches: an enucleation (local dissection) or so-called subtotal superficial parotidectomy and lateral or superficial total parotidectomy. Histopathological characteristics of PAs especially of capsular alterations such as thin capsule areas, capsule-free regions, capsule penetration, satellite nodules and pseudopodia in the different subtypes are important for the choice of surgical treatment and the first explanation for tumor recurrence. In our study we describe a morphological features of 84 cases of pleomorphic adenoma of parotid gland from elderly patients treated by a surgical "enucleation like" method called nucleoresection
Chemical and Thermal Effects of Trace Components in Hydrogen Rich Gases on Combustion
The production of carbon-neutral fuels through clean energy has been defined as a target by the European Union and by several international institutions. If the concepts are available, hydrogen, in particular, is considered to be one of the most target-oriented, ecologically and economically realizable approaches. In terms of safety, long-time storage and long-distance transport of hydrogen are still under development. However, pipeline systems similar to those for natural gas are being considered. Gas quality criteria will have to be developed for this case. The effects of trace components in the hydrogen on chemical and thermal aspects are not yet sufficiently understood and need to be characterized more precisely. For these reasons, this work presents a detailed analysis for a more complete understanding of the phenomena involved. More specifically, the flame structure, temperature profile and overall reactivity were first determined for gas mixtures analyzed under four varying dilutions of carbon dioxide, carbon oxide, nitrogen and methane in hydrogen. The characterization of the total reactivity and the laminar burning velocity offers an appealing solution to quantify the effects of dilution. The most distinctive effects of the operating conditions on the ignition phenomena have been worked out numerically for the lower and upper boundaries and have been discussed. The results collected in this work provide a robust feature for a detailed evaluation of normal operation as well as the accidental release of the hydrogen-rich fuels
Design of sustainable reactor based on key performance indicators
The design of chemical reactors has been largely considered primarily related to techno-economic evaluations. However, the recent need for sustainable solutions and processes has promoted the inclusion of environmental and safety parameters to identify the most suitable solution. In this sense, an innovative procedure has been developed in this work to identify and design a reactive section in chemical processes. To this aim, different key performance indicators have been defined and quantified for each domain considered within the analysis, namely technological, economic, environmental, and safety domains. In addition, the safety aspects have been quantified by integrating Semenov's theory and Varma, Morbidelli and Wu's theory. The validity and potentiality of the proposed procedure have been tested and shown by applying it to a case study representative for the scale-up of pharmaceutical processes: the industrial synthesis of a Vitamin A intermediate. A preliminary design has been performed for different configurations based on apparent kinetics determined from experimental data and ab initio coefficients available in the current literature. Among the analysed solutions, a single reactor with a volume of 15.90 m3 has been indicated as the most suitable for the process requirements regarding overall sustainability. Hence, the developed procedure can be intended as a powerful tool for screening among available configurations, enabling a more informed decision by simplifying and optimising the scale-up and the detailed design
Delineating a new critical region for juvenile myoclonic epilepsy at the 22q11.2 chromosome
No abstract availabl
Domino effects related to explosions in the framework of land use planning
The present study analyses the possible escalation due to the damage of industrial equipment containing hazardous materials loaded by pressure waves produced either by an accidental source as a Vapour Cloud Explosion, or by a voluntary external attack such as the explosion of a TNT charge located nearby the industrial facility. The results obtained evidence the similarities and the differences for the two explosion sources in terms of structural damage, loss of containment and of expected impacts on the population. In particular, a specific vulnerability assessment was carried out defining a case-study in order to evidence the different potential impact of domino effect triggered by internal process causes respect to escalation scenarios caused by external acts of interference. © 2013, AIDIC Servizi S.r.l
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