1,378 research outputs found
El transporte óseo : una alternativa en el tratamiento de los defectos óseos segmentarios masivos
Se presentan 3 casos de pseudoartrosis infectada de tibia y 2 de necrosis
ósea s postraumáticas, en las que tras la resección radical del fragmento infectado o
desvitalizado quedó un masiv o defecto óseo segmentario . Fueron tratadas mediant e
transporte óseo según la técnica de Ilizarov. En todos los casos se consiguió la consolidación
en el defecto óseo segmentario. Uno de los casos presentó una infección a nivel
del regenerado óseo que se trató con drenaje del absceso, relleno de hues o esponjoso
homólogo y posterior recubrimiento con un colgajo por rotación de gemelo interno e
injerto de pie l libre. Se concluy e que e l transport e óseo e s un método seguro, con e l
que se consigue un hues o de gran calidad y es relativament e rápido en el tratamiento
de defectos óseos segmentarios de etiología traumática o infecciosa.We present 3 case s of infected pseudoarthrosis of the tibia and 2 postraumatic
bone necrosis in which after radical resection of the infected or necrotic bone
fragment, a severe bone defect remained. The treatment consisted of transporting a
fragment of the same bone using the external fixator according to the Ilizarov technique.
In all cases consolidation and new bone formation wer e achieved. In one case, and
infection of the regenerated bone occurred, which was treated with drainage and grafting
with homologous cancellous bone , and posterior covering with a flap of rotated
medial gastrocnemius and skin graft. We conclude that bone transpor t is a safe method,
that the new formed bone is of great quality and that it is a relatively rapid treatment
for severe bone defects due to a traumatic or infectious aetiology
Preparation of magnetite-based catalysts and their application in heterogeneous Fenton oxidation - A review
This study presents a critical review on the application of magnetite-based catalysts to industrial wastewater decontamination by heterogeneous Fenton oxidation. The use of magnetic materials in this field started only around 2008 and continues growing increasingly year by year. The potential of these materials derives from their higher ability for degradation of recalcitrant pollutants compared to the conventional iron-supported catalysts due to the presence of both Fe(II) and Fe(III) species. In addition, their magnetic properties allow their easy, fast and inexpensive separation from the reaction medium. The magnetic materials applied up to now can be classified in three general groups: magnetic natural minerals, in-situ-produced magnetic materials and ferromagnetic nanoparticles. A survey of the catalysts investigated so far is presented paying attention to their nature and competitive features in terms of activity and durabilityThis research has been supported by the Spanish MICINN through the project CTQ2013-4196-R and by the CM through the project S2013/MAE-271
Improved wet peroxide oxidation strategies for the treatment of chlorophenols
Different advanced oxidation strategies have been investigated for the treatment of chlorophenols in aqueous phase with the aim of improving the removal efficiency in terms of mineralization, remanent by-products and kinetics. Those strategies were homogeneous Fenton-like oxidation and CWPO with two different own-prepared FexOy/γ-Al2O3 catalysts. The intensification of the process by increasing the temperature has been also evaluated. CWPO of chlorophenols with those catalysts has proved to be more efficient than homogeneous Fenton-like oxidation due to a lower rate of H2O2 decomposition allowing a higher availability of hydroxyl radicals along the course of reaction. Increasing the temperature clearly improved the oxidation rate and mineralization degree of both homogeneous Fenton-like oxidation and CWPO, achieving almost 90% TOC reduction after 1h at stoichiometric H2O2 dose, 100mgL-1 initial chlorophenol concentration, 1gL-1 Fe3O4/γ-Al2O3 catalyst, pH 3 and 90°C temperature. Both FexOy/γ-Al2O3 catalysts suffered fairly low iron leaching (<5%) and a remarkable stability in a three-cycles test with 2,4,6-TCP. The use of the magnetic catalyst is preferable due to its easy separation and recovery from the liquid phase by a magnet. Its magnetic properties remained unchanged after use in CWPOThis research has been supported by the Spanish MICINN through the projects CTQ2008-03988 and CTQ2010-14807 and by the CM through the project S-2009/AMB-1588. M. Munoz thanks the Spanish Ministry of Education for a FPU research gran
Triclosan breakdown by Fenton-like oxidation
Fenton-like oxidation has proved to be highly efficient for the removal of triclosan, a highly toxic emerging water pollutant. From 10mg/L starting aqueous solutions complete conversion of triclosan was achieved in less than 1h at 25°C and around 20min at 50°C with 1mg/L Fe3+ and H2O2 at the theoretical stoichiometric amount (25mg/L). From the evolution of byproducts a reaction pathway has been proposed according to which oxidation of triclosan gives rise to several aromatic intermediates (mainly, p-hydroquinone of triclosan and 2,4-dichlorophenol) which evolve to short-chain organic acids. These compounds are mineralized except oxalic acid. A dramatic decrease of ecotoxicity was achieved in a relatively short time (more than 95% in 15min at 35°C). The evolution of ecotoxicity is intimately related to the disappearance of triclosan, much more toxic than the aromatic oxidation intermediates. This disappearance was successfully described by a simple pseudo-first order rate equation with an apparent activation energy value close to 27kJ/mol. The apparent rate constant at 25°C was several orders of magnitude higher than the reported in the literature for other chlorophenolic compounds indicating a higher susceptibility of triclosan to OH radical attackThis research has been supported by the Spanish MICINN through the project CTQ2008-03988 and by the CM through the project S-2009/AMB-158
Langerin-Heparin Interaction: Two Binding Sites for Small and Large Ligands as revealed by a combination of NMR Spectroscopy and Cross-Linking Mapping Experiments
Langerin is a C-type lectin present on Langerhans cells that mediates capture of pathogens in a carbohydrate-dependent manner, leading to subsequent internalization and elimination in the cellular organelles called Birbeck granules. This mechanism mediated by langerin was shown to constitute a natural barrier for HIV-1 particle transmission. Besides interacting specifically with high mannose and fucosylated neutral carbohydrate structures, langerin has the ability to bind sulfated carbohydrate ligands as 6-sulfated galactosides in the Ca2+ dependent binding site. Very recently langerin was demonstrated to interact with sulfated glycosaminoglycans (GAGs), in a Ca2+ independent way, resulting in the proposal of a new binding site for GAGs. Based on those results, we have conducted a structural study of the interactions of small heparin (HEP) like oligosaccharides with langerin in solution. Heparin-bead cross-linking experiments, an approach specifically designed to identify HEP/HS binding sites in proteins were first carried out and experimentally validated the previously proposed model for the interaction of Lg ECD with 6 kDa HEP. High-resolution NMR studies of a set of 8 synthetic HEP-like trisaccharides harboring different sulfation patterns demonstrated that all of them bound to langerin in a Ca2+ dependent way. The binding epitopes were determined by STD NMR and the bound conformations by transferred NOESY experiments. These experimental data were combined with docking and molecular dynamics and resulted in the proposal of a binding mode characterized by the coordination of calcium by the two equatorial hydroxyl groups OH3 and OH4 at the non-reducing end. The binding also includes the carboxylate group at the adjacent iduronate residue. Such epitope is shared by all the 8 ligands, explaining the absence of any impact on binding from their differences in substitution pattern. Finally, in contrast to the small trisaccharides, we demonstrated that a longer HEP-like hexasaccharide, bearing an additional O-sulfate group at the non-reducing end, which precludes binding to the Ca2+ site, interacts with langerin in the previously identified Ca2+ independent binding site
Electricity generation by microorganisms in the sediment-water interface of an extreme acidic microcosm
The attachment of microorganisms to electrodes is of great interest for electricity generation in microbial fuel cells (MFC) or other applications in bioelectrochemical systems (BES). In this work, a microcosm of the acidic ecosystem of Río Tinto was built and graphite electrodes were introduced at different points. This allowed the study of electricity generation in the sediment/water interface and the involvement of acidophilic microorganisms as biocatalysts of the anodic and cathodic reactions in a fuel-cell configuration. Current densities and power outputs of up to 3.5 A/m2 and 0.3 W/m2, respectively, were measured at pH 3. Microbial analyses of the electrode surfaces showed that Acidiphilium spp., which uses organic compounds as electron donors, were the predominant biocatalysts of the anodic reactions, whereas the aerobic iron oxidizers Acidithiobacillus ferrooxidans and Leptospirillum spp. were detected mainly on the cathode surface. 
Pre-multisymplectic constraint algorithm for field theories
We present a geometric algorithm for obtaining consistent solutions to
systems of partial differential equations, mainly arising from singular
covariant first-order classical field theories. This algorithm gives an
intrinsic description of all the constraint submanifolds.
The field equations are stated geometrically, either representing their
solutions by integrable connections or, what is equivalent, by certain kinds of
integrable m-vector fields. First, we consider the problem of finding
connections or multivector fields solutions to the field equations in a general
framework: a pre-multisymplectic fibre bundle (which will be identified with
the first-order jet bundle and the multimomentum bundle when Lagrangian and
Hamiltonian field theories are considered). Then, the problem is stated and
solved in a linear context, and a pointwise application of the results leads to
the algorithm for the general case. In a second step, the integrability of the
solutions is also studied.
Finally, the method is applied to Lagrangian and Hamiltonian field theories
and, for the former, the problem of finding holonomic solutions is also
analized.Comment: 30 pp. Presented in the International Workshop on Geometric Methods
in Modern Physics (Firenze, April 2005
Velocity-Based Heuristic Evaluation for Path Planning and Vehicle Routing for Victim Assistance in Disaster Scenarios
Published in "Robot 2019: Fourth Iberian Robotics Conference. Advances in Intelligent Systems and Computing, Vol 1093. Silva M., Luís Lima J., Reis L., Sanfeliu A., Tardioli D. (eds)" published by Springer, Cham. Avalaible online at: https://doi.org/10.1007.987-3-030-36150-1_10Natural and human-made disasters require effective victim
assistance and last-mile relief supply operations with teams of ground vehicles.
In these applications, digital elevation models (DEM) can provide
accurate knowledge for safe vehicle motion planning but grid representation
results in very large search graphs. Furthermore, travel time, which
becomes a crucial cost optimization criterion, may be affected by inclination
and other challenging terrain characteristics. In this paper, our goal
is to evaluate a search heuristic function based on anisotropic vehicle velocity
restrictions for building the cost matrix required for multi-vehicle
routing on natural terrain and disaster sites. The heuristic is applied to
compute the fastest travel times between every pair of matrix elements
by means of a path planning algorithm. The analysis is based on a case
study on the ortophotographic-based DEM of natural terrain with different
target points, where theUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
This work has received funding from the national project RTI2018-093421-B-I00
(Spanish Government), the University of Malaga (Andalucía Tech) and the grant
BES-2016-077022 of the European Social Fund
Receding-horizon model predictive control for a three-phase VSI with an LCL filter
© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper presents a Continuous Control Set Model Predictive Control with receding horizon for a threephase voltage source inverter with LCL filter, using a reduced model of the converter. The main advantages of using this reduced model is that an active damping can be achieved while the computational burden is reduced. Besides, in order to eliminate the model uncertainties, and also to achieve a zero steady state error, the proposed converter model includes an embedded integrator. Regarding the control scheme, a Kalman filter is used in order to estimate the three-phase currents without oscillation. The objective is to find the control signals vector that minimizes the error between the current and its reference. It is important to remark that the control signals obtained fromthe cost function can be used directly in a space vector modulator, without the use of additional controllers such as proportionalintegral or proportional-resonant. Compared with the Finite Control Set Model Predictive Control, the proposedmethod operates at fixed switching frequency without using any restriction in the cost function. Simulation and experimental results show that this proposalworks correctly even in case of grid harmonics and voltage sags.Peer ReviewedPostprint (author's final draft
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