Kinetics of wet peroxide oxidation of phenol with a gold/activated carbon catalyst

Gold nanoparticles supported on activated carbon (Au/AC) have been tested in catalytic wet peroxide oxidation using phenol as target pollutant. In the current work, the effect of several operating conditions, including initial pH (3.5–10.5), catalyst load (0–6 g/L), initial phenol concentration (0.1–5 g/L), hydrogen peroxide dose (4–100% of the theoretical stoichiometric amount) and reaction temperature (50–80 °C) has been investigated. The results show that the Au/AC catalyst would be useful at relatively high pollutant to catalyst ratios (at least 0.4 w/w) and it can work efficiently within a wide range of pH (3.5–7.5). The catalyst suffers rapid deactivation but its activity can be completely restored by an oxidative thermal treatment at low temperature (200 °C). A kinetic model is presented, capable of describing the experimental results. This model is based on a rate equation of order one for hydrogen peroxide consumption and two for phenol oxidation and includes the catalyst deactivation and its temperature dependenceThe authors wish to thank the Spanish MICINN for the financial support through the projects CTQ2008-03988/PPQ and CTQ2010-14807. The Comunidad Autónoma de Madrid is also gratefully acknowledged for the financial support through the project S2009/AMB-158

Double-zero degeneracy and heteroclinic cycles in a perturbation of the Lorenz system

In this paper we consider a 3D three-parameter unfolding close to the normal form of the triple-zero bifurcation exhibited by the Lorenz system. First we study analytically the double-zero degeneracy (a double-zero eigenvalue with geometric multiplicity two) and two Hopf bifurcations. We focus on the more complex case in which the double-zero degeneracy organizes several codimension-one singularities, namely transcritical, pitchfork, Hopf and heteroclinic bifurcations. The analysis of the normal form of a Hopf-transcritical bifurcation allows to obtain the expressions for the corresponding bifurcation curves. A degenerate double-zero bifurcation is also considered. The theoretical information obtained is very helpful to start a numerical study of the 3D system. Thus, the presence of degenerate heteroclinic and homoclinic orbits, T-point heteroclinic loops and chaotic attractors is detected. We find numerical evidence that, at least, four curves of codimension-two global bifurcations are related to the triple-zero degeneracy in the system analyzed.Ministerio de Economía y Competitividad MTM2017-87915-C2-1-PMinisterio de Ciencia, Innovación y Universidades - Fondos FEDER PGC2018-096265-B-I0Consejería de Economía, Innovación, Ciencia y Empleo - Junta de Andalucía FQM-276, TIC-0130, UHU-1260150 y P20_0116

Role of leaf hydraulic conductance in the regulation of stomatal conductance in almond and olive in response to water stress

11 páginas..-- 5 figuras.-- 1 tablas.-- 55 referencias.-- We thank A. Montero for field work assistance, J. Perez Hormaeche for helping us with the VD images analysis and T. Brodribb and J.M. Torres-Ruiz for discussion.The decrease of stomatal conductance (gs) is one of the prime responses to water shortage and the main determinant of yield limitation in fruit trees. Understanding the mechanisms related to stomatal closure in response to imposed water stress is crucial for correct irrigation management. The loss of leaf hydraulic functioning is considered as one of the major factors triggering stomatal closure. Thus, we conducted an experiment to quantify the dehydration response of leaf hydraulic conductance (Kleaf) and its impact on gs in two Mediterranean fruit tree species, one deciduous (almond) and one evergreen (olive). Our hypothesis was that a higher Kleaf would be associated with a higher gs and that the reduction in Kleaf would predict the reduction in gs in both species. We measured Kleaf in olive and almond during a cycle of irrigation withholding. We also compared the results of two methods to measure Kleaf: dynamic rehydration kinetics and evaporative flux methods. In addition, determined gs, leaf water potential (Ψleaf), vein density, photosynthetic capacity and turgor loss point. Results showed that gs was higher in almond than in olive and so was Kleaf (Kmax = 4.70 and 3.42 mmol s-1 MPa-1 m-2, in almond and olive, respectively) for Ψleaf > -1.2 MPa. At greater water stress levels than -1.2 MPa, however, Kleaf decreased exponentially, being similar for both species, while gs was still higher in almond than in olive. We conclude that although the Kleaf decrease with increasing water stress does not drive unequivocally the gs response to water stress, Kleaf is the variable most strongly related to the gs response to water stress, especially in olive. Other variables such as the increase in abscisic acid (ABA) may be playing an important role in gs regulation, although in our study the gs-ABA relationship did not show a clear pattern..This work was funded by the Spanish Ministry of Science and Innovation (research project AGL2009-11310/AGR). V.H.-S. benefited from a Juan de la Cierva research fellowship from the Spanish Ministry of Science and Innovation and C.M.R.-D. benefited from a FPDI research fellowship from the Junta de Andalucí

Detection of mecC-Methicillin-resistant Staphylococcus aureus isolates in river water : a potential role for water in the environmental dissemination

Methicillin-resistant Staphylococcus aureus (MRSA) is a public health concern due to limited treatment options. The recent description of a mecA homologue, mecC in human and cattle, led to studies to detect this new variant in human and other animal species. Detection of mecC in wild boar and fallow deer in a Spanish game estate led us to further investigate the presence of mecC-MRSA at this location. Samples from cattle, wild animals, workers and river water were tested. A further three mecC-MRSA isolates were obtained from river water. Molecular characterization (multilocus sequence typing and spa typing) and antimicrobial susceptibility testing (broth microdilution) showed that isolates were similar to those detected in wild animals. Whole genome sequencing confirmed that the isolates from the river water and wild animals in the same geographic area were all closely related isolates of ST425 mecC-MRSA. The presence of mecC-MRSA in the river water highlights the potential role of water in the dissemination of mecC-MRSA

Balancing porosity and mechanical properties of titanium samples to favor cellular growth against bacteria

Two main problems limit the success of titanium implants: bacterial infection, which restricts their osseointegration capacity; and the stiffness mismatch between the implant and the host cortical bone, which promotes bone resorption and risk of fracture. Porosity incorporation may reduce this difference in stiffness but compromise biomechanical behavior. In this work, the relationship between the microstructure (content, size, and shape of pores) and the antibacterial and cellular behavior of samples fabricated by the space-holder technique (50 vol % NH4HCO3 and three ranges of particle sizes) is established. Results are discussed in terms of the best biomechanical properties and biofunctional activity balance (cell biocompatibility and antibacterial behavior). All substrates achieved suitable cell biocompatibility of premioblast and osteoblast in adhesion and proliferation processes. It is worth to highlighting that samples fabricated with the 100–200 μm space-holder present better mechanical behavior—in terms of stiffness, microhardness, and yield strength—which make them a very suitable material to replace cortical bone tissues. Those results exposed the relationship between the surface properties and the race of bacteria and mammalian cells for the surface with the aim to promote cellular growth over bacteria.University of Seville (Spain) VI Plan Propio de Investigación y Transferencia—US 2018, I.3A

Switching Costs in the European Postal Service. Are There Any Solutions?

[Abstract] This article examines the costs of switching that may exist in the European postal sector, where it is carried out an ambitious process of opening to competition since 1997. Inadequate regulation of the access to some elements of postal infrastructure or services within the scope of the universal postal service exists. This article proposes adaptations to ensure transparent and non-discriminatory access conditions to elements of postal infrastructure in line with the sectorial directives aimed at strengthening competition in the long term in the postal market. The proposed adaptations focus on services such as postcode systems, address databases, post office boxes, delivery boxes, re-direction and return to sender services. All of them can help reduce the switching cost and thus strengthen competition

A CMOS 0.8 μm fully differential current mode buffer for HF SI circuits

El pdf del artículo es la versión post-print.We present a high-frequency fully-differential current-mode buffer to interface off-chip currents with no significant degradation of the frequency response, and to measure current-mode ICs using standard equipment. It has been fabricated in a 0.8μm double-poly double-metal CMOS technology and features more than 37MHz bandwidth. In order to show its functionality, this unit has been incorporated to the front end of a Switched-Current Band-Pass ΣΔ modulator featuring 9 bit dynamic range at 10MHz clock frequency for a 30kHz signal bandwidth centered at 2.5MHz.Peer reviewe

Measuring the Quality of Model-Driven Projects with NDT-Quality

Model-driven web engineering (MDWE) is a new paradigm which provides satisfactory results in the development of web software systems. However, as can be concluded from several research works, MDWE provokes traceability problems and the necessity of managing constraints in metamodel instances and transformation executions. The management of these aspects is usually executed manually in the most of MDWE approaches. Nevertheless, model-driven paradigm itself can offer suitable ways to manage them. This chapter presents NDT-Quality, an approach to measure the quality of web projects developed with NDT (navigational development techniques), and offers a view about the application of this tool in real web projects.Ministerio de Educación y Ciencia TIN2007-67843-C06-03Ministerio de Educación y Ciencia TIN2007-30391-

The dynamics of radial sap flux density reflects changes in stomatal conductance in response to soil and air water deficit

10 páginas.-- 7 figuras.-- 1 tabla.-- 53 referenciasWater scarcity in semiarid regions of Europe threatens the sustainability of fruit tree orchards unless irrigation water is optimized and scheduled in deficit irrigation strategies. Stomatal conductance (gs) is one of the best indicators of plant water stress, since it is placed in the crossroad between water and CO2 fluxes at the leaf level. Unfortunately, it is not possible to measure gs automatically and continuously, which reduces its potential for irrigation scheduling. In this work we examined the use of sap flux density (Js) in the outer rings of the sapwood of olive trees as a surrogate of gs. The working hypothesis was that as olive trees are well-coupled to atmosphere because of their small leaves, the ratio of Js to air vapor pressure deficit (D) should correlate well with the dynamics of gs in the canopy. It was also expected that current year, sun exposed leaves were mainly connected to the outer rings of the sapwood, and the oldest, shaded leaves to the inner rings. This was tested by measuring gs in new, sun-exposed leaves vs gs in old, shaded leaves. Both hypotheses were contrasted and our results confirmed that gs can be estimated from Js/D (R2 of the relationships were always higher than 0.8). A wide range of estimated gs values (0.350-0.025molm-2s-1) were derived from Js measurements in an olive orchard under three different irrigation regimes. Results were satisfactory and open the possibility of applying this method to estimate gs and use it either as a reliable water stress indicator or in transpiration and photosynthesis models applied to fruit tree orchards under a wide range of water stress conditions.This experiment was funded by the Spanish Ministry of Science and Innovation, research project AGL2009-11310/AGR and by the Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía (research project AGR-6456). Dr. Hernandez-Santana benefited from a Juan de la Cierva postdoctoral research fellowship from the Spanish Ministry of Science and Innovation. Thanks are due to the owners of Internacional Olivarera, S.A.U. (Interoliva), for allowing us to make the experiments in the Sanabria orchard.Peer reviewe