160 research outputs found
Modeling electrodialysis and a photochemical process for their integration in saline wastewater treatment.
Oxidation processes can be used to treat industrial wastewater containing non-biodegradable organic compounds. However, the presence of dissolved salts may inhibit or retard the treatment process. In this study, wastewater desalination by electrodialysis (ED) associated with an advanced oxidation process (photo-Fenton) was applied to an aqueous NaCl solution containing phenol. The influence of process variables on the demineralization factor was investigated for ED in pilot scale and a correlation was obtained between the phenol, salt and water fluxes with the driving force. The oxidation process was investigated in a laboratory batch reactor and a model based on artificial neural networks was developed by fitting the experimental data describing the reaction rate as a function of the input variables. With the experimental parameters of both processes, a dynamic model was developed for ED and a continuous model, using a plug flow reactor approach, for the oxidation process. Finally, the hybrid model simulation could validate different scenarios of the integrated system and can be used for process optimization
Rail Infrastructure Pricing For Intercity Passenger Services In Europe: Possible Impacts On The Railways Competitive Framework
At the beginning of the 90’s, the European Union initiated a railways reform with the aim to face the decline of railway transport, as well as to increase railway competitiveness and interoperability at European scale. The First Railway Package of this reform focused on the split between infrastructure management and operation and, therefore, on the establishment of pricing systems. Due to lack of straight definition, the application of the Directives on infrastructure charges in the different European countries has given rise to a large spectrum of charging systems. It is a direct consequence of the differences in the charging philosophies (MC –marginal cost, MC+ - marginal cost with mark-ups, FC –Full Cost recovery, etc.), the charging types (single tariff, two-parts tariff) and the parameters (or variables) chosen for defining the amount of the charge in each particular case. This paper analyses the rail infrastructure charges in 23 European countries from the point of view of the parameters used for defining them. The analysis deepens the knowledge of qualitative differences between these countries’ pricing structure. Furthermore, it analyses its consequences in the total amount of the charge to be paid by passenger services running through links considered to be the best national railways relations in each one of the countries studied. Concerning the qualitative analysis, forty-six different types of variables were identified for the whole of the systems analysed. With regard to the quantitative field,calculations reveal that infrastructure charges range from 14,6 €/train-km to 0,6 €/train-km for “comparable” national links. The last part of this paper discusses the weight of those fares for the use of infrastructure for intercity rail passenger services with regard to its competitor mode. Results from an analysis of 100 national and international links allow drawing some conclusions on the possible impacts of railway infrastructure pricing on the railways competitive framework in Europe.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne
Rail Infrastructure Pricing For Intercity Passenger Services In Europe: Possible Impacts On The Railways Competitive Framework
At the beginning of the 90’s, the European Union initiated a railways reform with the aim to face the decline of railway transport, as well as to increase railway competitiveness and interoperability at European scale. The First Railway Package of this reform focused on the split between infrastructure management and operation and, therefore, on the establishment of pricing systems. Due to lack of straight definition, the application of the Directives on infrastructure charges in the different European countries has given rise to a large spectrum of charging systems. It is a direct consequence of the differences in the charging philosophies (MC –marginal cost, MC+ - marginal cost with mark-ups, FC –Full Cost recovery, etc.), the charging types (single tariff, two-parts tariff) and the parameters (or variables) chosen for defining the amount of the charge in each particular case. This paper analyses the rail infrastructure charges in 23 European countries from the point of view of the parameters used for defining them. The analysis deepens the knowledge of qualitative differences between these countries’ pricing structure. Furthermore, it analyses its consequences in the total amount of the charge to be paid by passenger services running through links considered to be the best national railways relations in each one of the countries studied. Concerning the qualitative analysis, forty-six different types of variables were identified for the whole of the systems analysed. With regard to the quantitative field,calculations reveal that infrastructure charges range from 14,6 €/train-km to 0,6 €/train-km for “comparable” national links. The last part of this paper discusses the weight of those fares for the use of infrastructure for intercity rail passenger services with regard to its competitor mode. Results from an analysis of 100 national and international links allow drawing some conclusions on the possible impacts of railway infrastructure pricing on the railways competitive framework in Europe.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne
Tryptophanol-derived oxazolopiperidone lactams: identification of a hit compound as NMDA receptor antagonist
N-Methyl-D-Aspartate (NMDA) receptors are neuronal ionotropic channels that play an important role in memory and learning processes. Their exacerbated activation leads to neuron death by necrosis or apoptosis in a phenomenon called excitotoxicity. Compounds like memantine or amantadine act as antagonists of these receptors and are currently used for the treatment of Alzheimer's or Parkinson's diseases. We herein present the development of a series of new NMDA receptor antagonists using enantiopure tryptophanol and racemic δ-oxo-esters as synthetic precursors in only one synthetic step and good yields. The most active hit exhibited an IC50 of 63.4 µM in cultured rat cerebellar granule neurons thus being 1.5 fold more active than the positive control used, amantadine (IC50 = 92 µM). The versatility of our synthetic approach together with the well-defined absolute stereoutcome of the tryptophanol-derived oxazolopiperidones is currently being explored to produce valuable structure activity relationships for the development of new potent NMDAR antagonists
Hipertensió pulmonar en un malalt jove amb hipertensió portal
La hipertensió pulmonar és una complicació poc freqüent de la hipertensió portal. Presentem un cas d'hipertensió arterial pulmonar severa en un malalt de 28 anys amb el diagnòstic anatomo-patològic d'absència de conductes biliars intrahepàtics i cirrosi hepàtica
Aneurismes dissecants d'aorta ascendent. Tractament quirúrgic
Els aneurismes dissecants d'aorta constitueixen una malaltia molt greu, de mal pronòstic i que acostuma a plantejar problemes diagnòstics i terapèutics importants, especialment en els casos aguts. Al nostre país la publicació dels casos operats és escassa. El pronòstic d'aquesta malaltia, el tractament mèdico-quirúrgic i la tècnica a seguir depenen en gran part de la localització de l'aneurisma i de la intervenció que es faci. En aquesta comunicació revisarem la nostra experiència en aquells casos en què la cirurgia es va circumscriure a l'aorta ascendent, amb intervenció sobre la vàlvula aòrtica o sense, i valorarem els problemes diagnòstics que hem trobat i la nostra conducta actual
Photodegradation of Phenol over a Hybrid Organo-Inorganic Material: Iron(II) Hydroxyphosphonoacetate
Water treatment is a hot topic, and it will become much more important in the decades ahead. Advanced oxidation processes are being increasingly used for organic contaminant removal, for example using photo-Fenton reactions. Here we report the use of an organo-inorganic hybrid, Fe[HO3PCH(OH)COO]·2H2O, as Fenton photocatalyst for phenol oxidation with H2O2 under UVA radiation. Preactivation, catalyst content, and particle size parameters have been studied/optimized for increasing phenol mineralization. Upon reaction, iron species are leached from the catalyst making a homogeneous catalysis contribution to the overall phenol photo-oxidation. Under optimized conditions, the mineralization degree was slightly larger than 90% after 80 min of irradiation. Analysis by X-ray photoelectron spectroscopy revealed important chemical modifications occurring on the surface of the catalyst after activation and phenol photodegradation. The sustained slow delivery of iron species upon phenol photoreaction is advantageous as the mixed heterogeneous−homogeneous catalytic processes result in very high phenol mineralization.Proyecto nacional MAT2010-1517
A review of combined advanced oxidation technologies for the removal of organic pollutants from water
Water pollution through natural and anthropogenic activities has become a global problem causing short-and long-term impact on human and ecosystems. Substantial quantity of individual or mixtures of organic pollutants enter the surface water via point and nonpoint sources and thus affect the quality of freshwater. These pollutants are known to be toxic and difficult to remove by mere biological treatment. To date, most researches on the removal of organic pollutants from wastewater were based on the exploitation of individual treatment process. This single-treatment technology has inherent challenges and shortcomings with respect to efficiency and economics. Thus, application of two advanced treatment technologies characterized with high efficiency with respect to removal of primary and disinfection by-products in wastewater is desirable. This review article focuses on the application of integrated technologies such as electrohydraulic discharge with heterogeneous photocatalysts or sonophotocatalysis to remove target pollutants. The information gathered from more than 100 published articles, mostly laboratories studies, shows that process integration effectively remove and degrade recalcitrant toxic contaminants in wastewater better than single-technology processing. This review recommends an improvement on this technology (integrated electrohydraulic discharge with heterogeneous photocatalysts) viz-a-vis cost reduction in order to make it accessible and available in the rural and semi-urban settlement. Further recommendation includes development of an economic model to establish the cost implications of the combined technology. Proper monitoring, enforcement of the existing environmental regulations, and upgrading of current wastewater treatment plants with additional treatment steps such as photocatalysis and ozonation will greatly assist in the removal of environmental toxicants
Enoxaparin versus unfractionated heparin with fibrinolysis for ST-elevation myocardial infarction
Background: Unfractionated heparin is often used as adjunctive therapy with fibrinolysis in patients with ST-elevation myocardial infarction. We compared a low-molecular-weight heparin, enoxaparin, with unfractionated heparin for this purpose. Methods: We randomly assigned 20,506 patients with ST-elevation myocardial infarction who were scheduled to undergo fibrinolysis to receive enoxaparin throughout the index hospitalization or weight-based unfractionated heparin for at least 48 hours. The primary efficacy end point was death or nonfatal recurrent myocardial infarction through 30 days. Results: The primary end point occurred in 12.0 percent of patients in the unfractionated heparin group and 9.9 percent of those in the enoxaparin group (17 percent reduction in relative risk, P<0.001). Nonfatal reinfarction occurred in 4.5 percent of the patients receiving unfractionated heparin and 3.0 percent of those receiving enoxaparin (33 percent reduction in relative risk, P<0.001); 7.5 percent of patients given unfractionated heparin died, as did 6.9 percent of those given enoxaparin (P=0.11). The composite of death, nonfatal reinfarction, or urgent revascularization occurred in 14.5 percent of patients given unfractionated heparin and 11.7 percent of those given enoxaparin (P<0.001); major bleeding occurred in 1.4 percent and 2.1 percent, respectively (P<0.001). The composite of death, nonfatal reinfarction, or nonfatal intracranial hemorrhage (a measure of net clinical benefit) occurred in 12.2 percent of patients given unfractionated heparin and 10.1 percent of those given enoxaparin (P<0.001). Conclusions: In patients receiving fibrinolysis for ST-elevation myocardial infarction, treatment with enoxaparin throughout the index hospitalization is superior to treatment with unfractionated heparin for 48 hours but is associated with an increase in major bleeding episodes. These findings should be interpreted in the context of net clinical benefit
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