460 research outputs found

    Biokinetic model for nitrogen removal in free water surface constructed wetlands

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    [EN] In this article, a mechanistic biokinetic model for nitrogen removal in free water surface constructed wetlands treating eutrophic water was developed, including organic matter performance due to its importance in nitrogen removal by denitrification. Ten components and fourteen processes were introduced in order to simulate the forms of nitrogen and organic matter, the mechanisms of autotrophic and heterotrophic microorganisms in both aerobic and anoxic conditions, as well as macrophytes nitrogen uptake and release. Dissolved oxygen was introduced as an input variable with a time step of 0.5 days for mimicking eutrophic environments: aerobic conditions were assigned during daylight hours and anoxic conditions during the night. The sensitivity analysis showed that the most influential parameters were those related to the growth of heterotrophic and autotrophic microorganisms. The model was properly calibrated and validated in two full scale systems working in real conditions for treating eutrophic water from Lake L'Albufera (Valencia). In the studied systems, ammonium was mainly removed by the growth of autotrophic microorganisms (nitrification) whereas nitrate was removed by the anoxic growth of heterotrophic microorganisms (denitrification). Macrophyte uptake removed between 9 and 19% of the ammonium entering to the systems, although degradation of dead standing macrophytes returned a significant part to water column.We would like to acknowledge the support of Confederation Hidrografica del Jucar (CHJ, MMARM) and the staff members in Tancat de la Pipa. We also acknowledge the anonymous reviewers and the editor for their valuable comments to improve this paper.Gargallo Bellés, S.; Martín Monerris, M.; Oliver Rajadel, N.; Hernández Crespo, C. (2017). Biokinetic model for nitrogen removal in free water surface constructed wetlands. The Science of The Total Environment. 587:145-156. doi:10.1016/j.scitotenv.2017.02.089S14515658

    Sedimentation and resuspension modelling in free water surface constructed wetlands

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    [EN] Eutrophication is a widespread problem that is being tackled from many perspectives and the recently applied technology of constructed wetlands is being used in the treatment of eutrophic water. However, process-based models to simulate their performance are scarce, so in this work a mechanistic model was developed to simulate the removal of total suspended solids, phytoplankton and total phosphorus in free water surface constructed wetlands treating eutrophic water. The model represents the influence of the main factors of the biotope and biota on these water quality variables, and particular attention is paid to resuspension produced by wind and by avifauna. Likewise, the effect of emergent vegetation cover in sedimentation, resuspension and phytoplankton growth is included. Phytoplankton is considered to store phosphorus internally in order to use it when growing, and the contribution of phytoplankton concentration to the suspended solids budget is included. The software AQUASIM was used to calibrate and validate the model in two full-scale constructed wetlands treating eutrophic water from Lake l'Albufera de Valencia (Spain) for three years. The simulated data and field measurements showed satisfactory adjustments for the three studied variables. The budgets obtained for each variable reveal that sedimentation and resuspension are the main processes in total suspended solids performance. Sedimentation of organic particulate phosphorus is the most important process in total phosphorus removal. The sum of the effect of resuspension by avifauna and by wind increases by more than 50% the quantity of solids that enters the water column. The model reveals that simulating the effects of the emergent vegetation cover and resuspension is crucial for representing the performance of the studied variables. (C) 2016 Elsevier B.V. All rights reserved.We would like to strongly thank to Pablo Vera (SEO/BirdLife ) for him collaboration with waterfowl monitoring and data analysis and to Maria Antonia Rodrigo and Matilde Segura (ICBiBE, Universitat de València) for collecting Chl a data. We would also like acknowledge the support of Confederación Hidrográfica de Júcar (CHJ, MMARM) and the staff members in Tancat de la Pipa.Gargallo Bellés, S.; Martín Monerris, M.; Oliver Rajadel, N.; Hernández Crespo, C. (2016). Sedimentation and resuspension modelling in free water surface constructed wetlands. Ecological Engineering. 98:318-329. https://doi.org/10.1016/j.ecoleng.2016.09.014S3183299

    Controlled Anisotropic Deformation of Ag Nanoparticles by Si Ion Irradiation

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    The shape and alignment of silver nanoparticles embedded in a glass matrix is controlled using silicon ion irradiation. Symmetric silver nanoparticles are transformed into anisotropic particles whose larger axis is along the ion beam. Upon irradiation, the surface plasmon resonance of symmetric particles splits into two resonances whose separation depends on the fluence of the ion irradiation. Simulations of the optical absorbance show that the anisotropy is caused by the deformation and alignment of the nanoparticles, and that both properties are controlled with the irradiation fluence.Comment: Submitted to Phys. Rev. Lett. (October 14, 2005

    Correction: A Guideline and Checklist for Initiating and Managing Clozapine Treatment in Patients with Treatment-Resistant Schizophrenia

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    This article was published online on June 27, 2022. An error was subsequently identified in the article, and the following correction should be noted: In the original publication, section 4.6, page 667, the reference cited in the first full sentence in column 2 and in Table 5 on the same page that read: “This information can be used to optimize clozapine dosage (Table 5) [103].” “Table 5 Therapeutic drug monitoring (TDM)-informed decision-making algorithm for clozapine-treated patientsa [103]” “Adapted by permission from reference [103]” Should read: “This information can be used to optimize clozapine dosage (Table 5) [104].” “Table 5 Therapeutic drug monitoring (TDM)-informed decision-making algorithm for clozapine-treated patientsa [104]” “Adapted by permission from reference [104]” The original article has been corrected. © The Author(s) 2022

    A Guideline and Checklist for Initiating and Managing Clozapine Treatment in Patients with Treatment-Resistant Schizophrenia

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    Treatment-resistant schizophrenia (TRS) will affect about one in three patients with schizophrenia. Clozapine is the only treatment approved for TRS, and patients should be treated as soon as possible to improve their chances of achieving remission. Despite its effectiveness, concern over side effects, monitoring requirements, and inexperience with prescribing often result in long delays that can expose patients to unnecessary risks and compromise their chances of achieving favorable long-term outcomes. We critically reviewed the literature on clozapine use in TRS, focusing on guidelines, systematic reviews, and algorithms to identify strategies for improving clozapine safety and tolerability. Based on this, we have provided an overview of strategies to support early initiation of clozapine in patients with TRS based on the latest evidence and our clinical experience, and have summarized the key elements in a practical, evidence-based checklist for identifying and managing patients with TRS, with the aim of increasing confidence in prescribing and monitoring clozapine therapy

    Ablation and optical third-order nonlinearities in Ag nanoparticles

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    The optical damage associated with high intensity laser excitation of silver nanoparticles (NPs) was studied. In order to investigate the mechanisms of optical nonlinearity of a nanocomposite and their relation with its ablation threshold, a high-purity silica sample implanted with Ag ions was exposed to different nanosecond and picosecond laser irradiations. The magnitude and sign of picosecond refractive and absorptive nonlinearities were measured near and far from the surface plasmon resonance (SPR) of the Ag NPs with a self-diffraction technique. Saturable optical absorption and electronic polarization related to self-focusing were identified. Linear absorption is the main process involved in nanosecond laser ablation, but non-linearities are important for ultrashort picosecond pulses when the absorptive process become significantly dependent on the irradiance. We estimated that near the resonance, picosecond intraband transitions allow an expanded distribution of energy among the NPs, in comparison to the energy distribution resulting in a case of far from resonance, when the most important absorption takes place in silica. We measured important differences in the ablation threshold and we estimated that the high selectiveness of the SPR of Ag NPs as well as their corresponding optical nonlinearities can be strongly significant for laser-induced controlled explosions, with potential applications for biomedical photothermal processes

    Generation and Reactivity of Electron-Rich Carbenes on the Surface of Catalytic Gold Nanoparticles

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    [EN] The reactive nature of carbenes can be modulated, and ultimately reversed, by receiving additional electron density from a metal. Here, it is shown that Au nanoparticles (NPs) generate an electron-rich carbene on surface after transferring electron density to the carbonyl group of an in situ activated diazoacetate, as assessed by Fourier transformed infrared (FT¿IR) spectroscopy, magic angle spinning nuclear magnetic resonance (MAS NMR), and Raman spectroscopy. Density functional theory (DFT) calculations support the observed experimental values and unveil the participation of at least three different Au atoms during carbene stabilization. The surface stabilized carbene shows an extraordinary stability against nucleophiles and reacts with electrophiles to give new products. These findings showcase the ability of catalytic Au NPs to inject electron density in energetically high but symmetrically allowed valence orbitals of sluggish molecules.Financial support by MINECO through the Severo Ochoa program, RETOS program (CTQ2014-55178-R), and Ramon y Cajal Program (to A.L.-P.) is acknowledged. J.O.-M. thanks ITQ for the concession of a contract. We are thankful for the electron microscopy service of UPV.Oliver-Meseguer, J.; Boronat Zaragoza, M.; Vidal Moya, JA.; Concepción Heydorn, P.; Rivero-Crespo, MÁ.; Leyva Perez, A.; Corma Canós, A. (2018). Generation and Reactivity of Electron-Rich Carbenes on the Surface of Catalytic Gold Nanoparticles. Journal of the American Chemical Society. 140(9):3215-3218. https://doi.org/10.1021/jacs.7b13696S32153218140

    Experience on how to implement a preanalytical and POCT unit in Madrid’s IFEMA field hospital during this unprecedented COVID-19 emergency

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    To fight the virus SARS-CoV-2 spread to Europe from China and to give support to the collapsed public health system, the Spanish Health Authorities developed a field hospital located in the facilities of Madrid exhibition centre (IFEMA) to admit and treat patients diagnosed with SARS-CoV-2 infectious disease (COVID-19). The Department of Laboratory Medicine of La Paz University Hospital in Madrid (LMD-HULP) was designated to provide laboratory services. Due to the emergency, the IFEMA field hospital had to be prepared for patient admission in less than 1 week and the laboratory professionals had to collaborate in a multidisciplinary group to assure that resources were available to start on time. The LMD-HULP participated together with the managers in the design of the tests portfolio and the integration of the healthcare information systems (IS) (hospital IS, laboratory IS and POCT management system). Laboratorians developed a strategy to quickly train clinicians and nurses on test requests, sample collection procedures and management/handling of the POCT blood gas analyser both by written materials and training videos. The IFEMA´s preanalytical unit managed 3782 requests, and more than 11,000 samples from March 27th to April 30th. Furthermore, 1151 samples were measured by blood gas analysers. In conclusion, laboratory professionals must be resilient and have to respond timely in emergencies as this pandemic. The lab’s personnel selection, design and monitoring indicators to maintain and further improve the quality and value of laboratory services is crucial to support medical decision making and provide better patient care
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