196 research outputs found

    Efficacia di una terapia senza bendaggio con gel a base di trealosio ialuronato sodico carbomero, nella riparazione del danno corneale epiteliale di tipo meccanico vs terapia a base di pomata antibiotica oftalmica con bendaggio

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    Introduzione: la superficie oculare è una complessa unità funzionale, il cui normale funzionamento è regolato dal sistema nervoso, particolarmente espresso a livello corneale. Diverse patologie possono portare ad una alterazione della superficie oculare e tra queste le patologie traumatiche della superficie oculare. In caso di trauma lo scopo principale della terapia della superficie oculare è di riparare il danno epiteliale. L’effetto protettivo e riparativo di una formulazione in gel a base di trealosio/ialuronato sodico/carbomero può trovare una valida applicazione nei processi di riparazione di danno epiteliale. Scopo: valutare l’efficacia riparativa nei confronti del danno epiteliale di tipo meccanico, di una formulazione in gel a base di trealosio/ialuronato sodico/carbomero, senza bendaggio oculare in confronto ad una terapia topica antibiotica con bendaggio oculare. Materiali e metodi: studio osservazionale condotto su 262 pazienti afferiti presso la clinica Oculistica di Roma nel periodo maggio 2014 – giugno 2017 per una lesione corneale e/o corneo-congiuntivale di natura da corpo estraneo o per abrasione corneale traumatica. È stata ottenuta l’approvazione del Comitato Etico ed il consenso informato dei pazienti. Il primo gruppo era costituito da 158 pazienti sottoposti a rimozione di corpo estraneo corneale e trattati per 7 giorni con le seguenti modalità: 83 pazienti con una formulazione in gel a base di trealosio/ialuronato sodico/carbomero quattro volte al giorno senza bendaggio oculare; 75 pazienti con una terapia topica antibiotica quattro volte al giorno con bendaggio oculare. Il secondo gruppo costituito da 104 pazienti con abrasione corneale e trattati con le stesse modalità descritte nel primo gruppo di pazienti (50 vs 54 rispettivamente). Risultati: dopo 4 giorni di trattamento la percentuale di guarigione dei pazienti trattati con la formulazione in gel a base di trealosio/ialuronato sodico/carbomero rispetto ai pazienti trattati con terapia topica antibiotica era significativamente superiore in entrambi i gruppi (73% vs 32%; p<0,01 Gruppo 1) (78% vs 29%; p<0,01 Gruppo 2). La differenza si è mantenuta anche dopo 7 giorni di trattamento (98% vs 91%; p<0,01 Gruppo 1) (100% vs 87% Gruppo 2; p<0,01). Una differenza statisticamente significativa dopo 4 giorni di trattamento è stata riscontrata per i parametri soggettivi come dolore (0,22 vs 0,47; p<0,01 Gruppo 1) (0.1 vs 0.5; p<0,01 Gruppo 2), bruciore (0,23 vs 0,79; p<0,01 Gruppo 1) (0.1 vs 0.8; p<0,01 Gruppo 2) e sensazione di corpo estraneo (0,51 vs 1,37; p<0,01 Gruppo 1) (0.4 vs 1.8; p<0,01 gruppo 2). Conclusioni: la terapia con una formulazione in gel a base di trealosio/ialuronato sodico/carbomero senza bendaggio sembra una valida alternativa all’applicazione di pomata oftalmica antibiotica con bendaggio.Introduction: The ocular surface is a complex functional unit whose normal functions are regulated by the nervous system, particularly expressed at the corneal level. Various diseases, and also traumatic injuries, can lead to the alteration of the ocular surface. In case of trauma, the main purpose of ocular surface therapy is to repair the epithelial damage. A gel formulation based on trehalose/sodium hyaluronate/carbomer may represent a valid strategy to help the epithelial repair processes, thanks to its protective and repairing action. Aim: To evaluate the effect of a gel formulation based on trehalose/sodium hyaluronate/carbomer without eye patching compared to topical antibiotic therapy with eye patching, in recovering epithelial damage caused by mechanical injury. Materials and methods: An observational study involving 262 patients referred to the Ophthalmology Clinic in Rome between May 2014 and June 2017 for corneal and/or cornealconjunctival lesion caused by a foreign body or by traumatic corneal abrasion. Ethical approval was obtained , and only consenting subjects were involved. The first group involved 158 patients who underwent corneal foreign body removal and were treated for 7 days as follows: 83 patients received a gel formulation based on trehalose/sodium hyaluronate/carbomer four times a day, without occlusive eye patch; 75 patients were treated with topical antibiotic therapy four times a day and occlusive eye patch. The second group included 104 patients with corneal abrasion who underwent the same treatments described for the first group of patients (50 vs 54 patients, respectively). Results: After 4 days of treatment, the recovery rate was significantly higher in both groups of patients treated with the gel formulation based on trehalose/sodium hyaluronate/carbomer, compared to patients treated with topical antibiotic therapy (73% vs 32%, p<0.01; Group 1) (78% vs 29%, p<0.01; Group 2). The difference was maintained even after 7 days of treatment (98% vs 91%, p<0.01; Group 1) (100% vs 87%, p<0.01; Group 2). A statistically significant difference was found after 4 days of treatment in subjective parameters such as pain (0.22 vs 0.47, p<0.01; Group 1) (0.1 vs 0.5, p<0.01; Group 2), burning sensation (0.23 vs 0.79, p<0.01; Group 1) (0.1 vs 0.8, p<0.01; Group 2) and foreign body sensation (0.51 vs 1.37, p<0.01; Group 1) (0.4 vs 1.8, p<0.01; Group 2). Conclusions: Treatment with a gel formulation based on trehalose/sodium hyaluronate/carbomer without occlusive patch seems a valid alternative to the application of an antibiotic ophthalmic ointment and occlusive eye patching

    Drag reduction induced by superhydrophobic surfaces in turbulent pipe flow

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    The drag reduction induced by superhydrophobic surfaces is investigated in a turbulent pipe flow. Wetted superhydrophobic surfaces are shown to trap gas bubbles in their asperities. This stops the liquid from coming in direct contact with the wall in that location, allowing the flow to slip over the air bubbles. We consider a well-defined texture with streamwise grooves at the walls in which the gas is expected to be entrapped. This configuration is modeled with alternating no-slip and shear-free boundary conditions at the wall. With respect to the classical turbulent pipe flow, a substantial drag reduction is observed which strongly depends on the grooves’ dimension and on the solid fraction, i.e., the ratio between the solid wall surface and the total surface of the pipe’s circumference. The drag reduction is due to the mean slip velocity at the wall which increases the flow rate at a fixed pressure drop. The enforced boundary conditions also produce peculiar turbulent structures which on the contrary decrease the flow rate. The two concurrent effects provide an overall flow rate increase as demonstrated by means of the mean axial momentum balance. This equation provides the balance between the mean pressure gradient, the Reynolds stress, the mean flow rate, and the mean slip velocity contribution

    First Scientific Results From The Infrared Astronomical Satellite (IRAS)

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    The Infrared Astronomical Satellite (IRAS) was successfully launched on 25 January 1983 and terminated science data acquisition on 22 November 1983. The in-orbit performance of the telescope has been described in two previous papers in these proceedings. A previous description of very preliminary scientific results from the mission has been given in these proceedings, while far more extensive reports have been given elsewhere. In this paper we will summarize some of the results obtained to date from the IRAS data. The work to date has sampled only a small fraction of the IRAS data; the study of the data from the IRAS survey will continue for many years to come

    Structure of turbulence in temporal planar jets

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    A detailed analysis of the structure of turbulence in a temporal planar turbulent jet is reported. Instantaneous snapshots of the flow and three-dimensional spatial correlation functions are considered. It is found that the flow is characterized by large-scale spanwise vortices whose motion is felt in the entire flow field. Superimposed to this large-scale motion, a hierarchy of turbulent structures is present. The most coherent ones take the form of quasi-streamwise vortices and high and low streamwise velocity streaks. The topology of these interacting structures is analyzed by quantitatively addressing their shape and size in the different flow regions. Such information is recognized to be relevant for a structural description of the otherwise disorganized motion in turbulent free-shear flows and can be used for the assessment of models based on coherent structure assumptions. Finally, the resulting scenario provides a phenomenological description of the elementary processes at the basis of turbulence in free-shear flows

    Elements for the Expected Mechanisms on Reduced Emissions from Deforestation and Degradation, REDD under UNFCCC

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    Carbon emissions from deforestation and degradation account for 20% of the global anthropogenic emissions (IPCC WG I, 2007). Since the eleventh session of the Conference of the Parties to the United Nations Convention on Climate Change (UNFCCC) in December 2005, strategies and incentives for Reduced Emissions from Deforestation and Degradation (REDD) have emerged as one of the most attended negotiation items. It is not easy to build an international agreement on the role of REDD in a future climate change regime, but now we are close to an achievable historical decision on the future of forests: the Bali mandate on REDD. In this paper we suggest some elements for an effective long-term implementation of a REDD mechanism under the UNFCCC and for closing gaps in the forestry accounting system. These elements are related both to ecological and political processes, reflecting some of the most critical and debated negotiation points. The proposed elements are: a) carbon (C) losses from forests; b) incentives for all stages of reducing emissions, stabilizing and maintaining forest C stocks; c) national approach; d) data availability at national scale; e) conservativeness approach for carbon accounting.JRC.H.2-Climate chang

    Spatially evolving cascades in temporal planar jets

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    Starting from an alternative decomposition of the turbulent field, a multi-dimensional statistical formalism for the description and understanding of turbulence in free-shear flows is proposed and applied to the symmetries of planar temporal jets. The theoretical framework is based on the exact equation for the second-order moment of the two-point velocity increment and allows us to trace, for the first time, the spatially evolving cascade processes at the basis of turbulence mixing and entrainment. Fascinating reverse energy cascade mechanisms are found to be responsible for the generation of long and wide structures in the interface region. Analogously to two-dimensional turbulence, the energy provided by these spatially ascending reverse cascades is found to be eventually dissipated by viscosity at large scales through friction shearing processes involving a thin cross-flow layer of these large-scale structures. Finally, the external non-turbulent region of the jet is also found to be active from an energetic point of view. It is found that pressure-mediated non-local phenomena of displacement of almost quiescent fluid give rise to non-turbulent fluctuations that in time, through transitional mechanisms, would contribute to the growth of the turbulent jet. Overall, the unexpected paths taken by the scale-energy flux in the combined physical/scale space, which are a substantial novelty with respect to known descriptions of turbulent mixing and entrainment, may have major repercussions on our theoretical understanding and modelling, as anticipated here by reduced equations capable of giving a simple scale-dependent description of the rich dynamics of the flow

    Elements for the expected mechanisms on 'reduced emissions from deforestation and degradation, REDD' under UNFCCC

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    Carbon emissions from deforestation and degradation account for about 20% of global anthropogenic emissions. Strategies and incentives for reduced emissions from deforestation and degradation (REDD) have emerged as one of the most active areas in the international climate change negotiations under the United Nations Framework Convention on Climate Change (UNFCCC). While the current negotiations focus on a REDD mechanism in developing countries, it should be recognized that risks of carbon losses from forests occur in all climate zones and also in industrialized countries. A future climate change agreement would be more effective if it included all carbon losses and gains from land use in all countries and climate zones. The REDD mechanism will be an important step towards reducing emissions from land use change in developing countries, but needs to be followed by steps in other land use systems and regions. A national approach to REDD and significant coverage globally are needed to deal with the risk that deforestation and degradation activities are displaced rather than avoided. Favourable institutional and governance conditions need to be established that guarantee in the long-term a stable incentive and control system for maintaining forest carbon stocks. Ambitious emission reductions from deforestation and forest degradation need sustained financial incentives, which go beyond positive incentives for reduced emissions but also give incentives for sustainable forest management. Current data limitations need-and can be-overcome in the coming years to allow accurate accounting of reduced emissions from deforestation and degradation. A proper application of the conservativeness approach in the REDD context could allow a simplified reporting of emissions from deforestation in a first phase, consistent with the already agreed UNFCCC reporting principles. [References: 19

    Countergradient turbulent transport in a plume with a crossflow

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    Direct numerical simulation of a turbulent forced buoyant plume in a crossflow is performed at a source Reynolds number Re0=1000\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} Re 0=1000{\text{ Re }}_0=1000\end{document}, Richardson number Ri0=1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}Ri0=1\mathrm{{Ri}}_0=1\end{document}, Prandtl number Pr=1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}Pr=1\mathrm{{Pr}}=1\end{document} and source-to-crossflow velocity ratio R0=1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}R0=1R_0=1\end{document}. The instantaneous and temporally averaged flow fields are assessed in detail, providing an overview of the flow dynamics. The velocity, temperature and pressure fields are used together with enstrophy fields to describe qualitatively the evolution of the plume as it is swept downstream by the crossflow, and the mechanisms involved in its evolution are outlined. The plume trajectory is determined quantitatively in a number of ways, and it is shown that the central streamline and the centre of buoyancy of the plume differ significantly-as with jets in crossflow, the central streamline is seen to follow the top of the plume, whereas the centre of buoyancy, by definition, describes the plume as a whole. We then investigate the turbulence properties inside the plume; in particular the eddy viscosity and diffusivity are presented, which are significant parameters in turbulence modelling. Assessment of turbulence production demonstrates the presence of regions where turbulence kinetic energy is redistributed to the kinetic energy of the mean flow, implying a negative eddy viscosity within certain regions of the domain. Similarly, the observation that the buoyancy flux and buoyancy gradient are anti-parallel in specific regions of the flow implies a negative eddy diffusivity in said regions, which must be realised in models of such flows in order to capture the countergradient transport of thermal properties. A characteristic eddy viscosity and diffusivity are presented, and shown to be approximately constant in the fully developed regime, resulting in a constant characteristic turbulent Prandtl number, in turn signifying self-similarity

    Preliminary studies on an innovative vertical axis wind turbine concept : SATVAWT

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    Vertical axis wind turbine concepts are particularly attractive for the urban environment for various reasons including adaptability to varying wind directions. On the other hand, these types of turbines suffer from various disadvantages including prohibitive costs. In this paper, we present an innovative concept of a Self Adjusting Lift Type Vertical Axis Wind Turbine (SATVAWT) being developed by the a consortium of local academia and industry. Although the project is still in its infancy some insight of the design is presented, particularly the aerodynamic and structural aspects of the blades which are being optimised for highest possible efficiency. Some results from numerical analysis tools are also presented. To provide easy start up, the turbine blades are at first retracted. Due to the accelerating motion, momentum is conserved by means of an increase in the polar moment of inertia about the axis of rotation. This causes the turbine blades to flex. In this position, advanced aerodynamic calculations using vortex methods have shown that the turbine should operate at a higher efficiency for the rated condition. Finite Element Analysis (FEA) tools have also been used to assess the structural feasibility of the turbine. The preliminary results presented here are encouraging and will form the basis for further computational and experimental analysis.Bajada New Energy Ltd., CD Power Saving Co. Ltd., Energy Investment Co. Ltd., Solar Engineering Ltd. & Solar Solutions Ltd.peer-reviewe

    No Forest Left Behind

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    Mitigating climate change by reducing deforestation should involve incentives for countries that currently have high forest cover and low deforestation rates
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