Challenges of aerobic granular sludge utilization: Fast start-up strategies and cationic pollutant removal.

Aerobic granular sludge (AGS) is a self-aggregated microorganism consortium with pollutant removal properties. The aim of this work is to study and review the application of aerobic granules for water treatment with special focus on new applications and methodologies. Carbon-nitrogen containing pollutants are the classic targets of AGS technology. Carbon and nitrogen removal of AGS are classified as a biodegradation process. More recently, the AGS granules have been studied as sorbent materials for wastewater treatment. In particular, the sorption of cationic pollutants has been studied through biosorption and bioaccumulation mechanisms without distinguishing when one or the other process is involved. AGS conformation made them suitable for complex wastewater treatment. Indeed, several studies have demonstrated the removal of polyvalent cationic pollutants even with higher capacity than conventional sorbent materials. However, this was achieved almost exclusively for synthetic substrates, with single cation evaluation and using in some cases only qualitative measures. For successful industrial AGS application in complex substrates, it is necessary to evaluate and demonstrate the technology in real industrial conditions and reduce the currently long start-up times which limits its utility. Two new strategies have been proposed: autoinducer molecules and the production of artificial granular from common active sludge with commercial alginate. Finally, the increase of research on AGS cations assimilation properties will allow a new point of view, where granules will be materials for the recovery of valuable metals from industrial wastewater streams.

The prediction of partial-nitrification-anammox performance in real industrial wastewater based on granular size.

To date, the partial nitrification-Anammox (PN-A) granular sludge size has been exclusively analyzed in synthetic substrates. In this work, different ranges of granular size of PN-A sludge were studied at low oxygen concentration using real industrial wastewater as, well as a synthetic substrate. The granular sludge was characterized by the specific nitrification activity (SNA), specific anammox activity (SAA), and granule sedimentation rate. The relative abundance of the bacterial consortium was assessed for each range of diameters through the fluorescence in situ hybridization (FISH) technique. SNA exhibits a direct association with the specific surface of granules, which proves the importance of the outer layer in the nitrification process. Even more critical, the flocculent sludge allowed the stability of the nitrifying activity. The SAA showed different performances faced the real industrial and synthetic substrates. With the synthetic substrate, the SAA decreased at higher diameter ranges, whereas with the industrial substrate, the SAA increased at higher diameter ranges. This situation is explained by the oxygen protection in the sludge maintained with industrial wastewater. The relative abundance of heterotrophic bacteria increased from 9.6 to 22%, due to the presence of organic matter in the industrial substrate. The granular sedimentation rate increased with the diameter of the granules with a linear correlation (R2 > 0.98). Thus, granular sizes can be selected through sedimentation rate control. A linear correlation between SAA and granular sludge diameter ranges was observed. With this correlation, an error of less than 11% in the prediction of SAA was achieved. The use of diameter measurement and granular sedimentation rate as routine techniques could contribute to the control and start-up of PN-A reactors. In the same sense, organic matter present in defined concentrations, can be beneficial for the granular sludge stability, and thus, for nitrogen removal.

Imágenes en obesidad: contribuyendo a un entendimiento más profundo de la enfermedad / Imaging in obesity: contributing to a deeper understanding of the disease

Resumen: la obesidad constituye un problema mayor de salud pública relevante en la actualidad, considerando que cumple un doble rol al actuar como factor de riesgo para la mayoría de las enfermedades crónicas no transmisibles y constituir una entidad nosológica independiente. Los estudios de imágenes han contribuido, desde diferentes perspectivas, a dilucidar los mecanismos propios de la enfermedad, sus complicaciones, progresión, mecanismos cognitivos involucrados y respuesta a diversos esquemas terapéuticos. El objetivo del presente artículo es proveer de una visión general respecto a cómo los estudios imagenológicos, especialmente basados en resonancia magnética, han profundizado la comprensión de los mecanismos metabólicos y neurocognitivos, relacionados, así como elementos vinculados al tratamiento. Adicionalmente se discuten posibles direcciones futuras en este campo.

Abstract: Obesity constitutes a relevant issue in public health. It acts both like a risk factor for most of the non-communicable diseases and as an independent nosologic entity. The imaging studies have contributed, from several perspectives, to elucidate the underlying mechanisms of the disease. its complications, progression, involved cognitive phenomena and the response to different therapeutic approaches. The objective of this article is to provide a global view about how the imaging studies, particularly those based on magnetic resonance imaging, have given a deeper comprehension of the related metabolic and cognitive mechanisms and some facts related to the treatment. Additionally, future directions of this field are discussed.

Efficient poultry manure management: anaerobic digestion with short hydraulic retention time to achieve high methane production.

The efficient treatment or appropriate final disposal of poultry manure (PM) to avoid serious environmental impacts is a great challenge. In this work, the optimization of a 2-stage anaerobic digestion system (ADS) for PM was studied with the aim of reaching a maximal methane yield with a short hydraulic retention time (HRT). Three activities were performed: The first activity, ADS 1, consisted of evaluating the effect of the substrate concentration and the HRT on the process, with a constant organic loading rate (OLR) of 3.66 ± 0.21 gVS L-1 d-1. The second activity, ADS 2, consisted of decreasing the HRT from 9.09 to 2.74 d with a constant substrate concentration. In the third activity, ADS 3, the substrate concentration was increased from 10.09 ± 1.41 to 35.25 ± 6.20 gVS L-1 with an average HRT of 4.66 ± 0.11 d. Maximal methane yields of 0.22, 0.21, and 0.22 LCH4 gVS-1 were reached for ADS 1, ADS 2, and ADS 3, respectively, at a low HRT (3.38 to 4.66 d) and high free ammonia concentration (between 323.05 ± 56.48 and 460.93 ± 135.40 mgN-NH3 L-1). These methane yields correspond to the production of 40.36 and 42.28 cubic meters of methane per ton of PM, respectively, and a laying hen produces between 47.45 and 54.75 kg of PM per year in Chile. Finally, this is the first study of the separate and combined effects of OLR, HRT and substrate concentration on the anaerobic digestion of PM. The results demonstrate the technical feasibility of the two-stage ADS treatment of PM with a short HRT; the system tolerates variations in the total ammonia nitrogen concentration of PM throughout the year and achieves a high methane yield when the correct operational conditions are selected.

Correction to: Effluent composition prediction of a two-stage anaerobic digestion process: machine learning and stoichiometry techniques.

The original publication of this paper contains a mistake. Unfortunately, an author was inadvertently missed out, Constanza Arriagada had participated in the operation of the anaerobic digesters cited in the work and now as a PhD student, she is involved in the production of other publication.

Factores asociados a la disfagia orofaríngea postictus / Factors associated with post-stroke oropharingeal dysphagia

Introducción. La disfagia neurógena es una secuela del ictus que en ocasiones pone en riesgo la vida del paciente. La magnitud del daño cerebral generado por el ictus comúnmente ocasiona la aparición de otros trastornos que acompañan a la disfagia y agravan la salud del paciente. Objetivo. Analizar posibles asociaciones entre trastornos de la comunicación, factores propios de la enfermedad, demográficos y comórbidos con disfagia en pacientes que sufrieron un ictus durante el ingreso hospitalario entre los años 2009 y 2011. Pacientes y métodos. Se estudiaron 1.519 historias clínicas de pacientes que presentaron ictus entre los años 2009 y 2011. Resultados. De los registros analizados, 206 presentaron disfagia (13,6%). El 80,1% de los casos de disfagia se concentró en pacientes de 60-89 años. El 66% de ellos permaneció hospitalizado durante más de 11 días. La edad (odds ratio = 2,36; p < 0,001), afasia (odds ratio = 4,47; p < 0,001), disartria (odds ratio = 4,95; p < 0,001), tiempo de hospitalización (odds ratio = 3,65; p < 0,001) e hipertensión arterial (odds ratio = 1,64; p = 0,023) se asociaron estadísticamente con disfagia. Finalmente, en el 73,3% de los casos con disfagia, se presentó disfagia más afasia o disartria o apraxia del habla, mientras que sólo el 26,7% tuvo exclusivamente disfagia. Conclusiones. La disfagia neurógena parece concomitar con trastornos de la comunicación, aumentar el tiempo de hospitalización y asociarse a hipertensión arterial. Sin embargo, se requieren estudios prospectivos que consideren un gran período de tiempo para confirmar estos hallazgos (AU)

Introduction. Neurogenic dysphagia is a consequence of stroke that sometimes threatens the patient’s life. The magnitude of the brain damage commonly generated by stroke generates the emergence of other disorders that accompany dysphagia and worsen the patient’s health. Aim. To analyze possible associations between communication disorders, disease factors, demographic factors and comorbidities with post-stroke dysphagia in years 2009 to 2011. Patients and methods. We studied 1519 medical records of patients that suffered stroke between 2009 and 2011. Results. From medical records reviewed, 206 had dysphagia (13.6%). 80,1% from dysphagic patients had between 60 to 89 years old. 66% from them stayed hospitalized for more than 11 days. Age (odds ratio = 2.36; p < 0.001), aphasia (odds ratio = 4.47; p < 0.001), dysarthria (odds ratio = 4.95; p < 0.001), time of hospitalization (odds ratio = 3.65; p < 0.001) and hypertension (odds ratio = 1.64; p = 0.023) were statistically associated with dysphagia. Finally, 73,3% from dysphagic patients they had dysphagia with aphasia or dysarthria or apraxia of speech, however, 26,7% only had dysphagia. Conclusion. Neurogenic dysphagia seems to be associated with communication disorders, increase the time of hospitalization and associated with a hypertension. However, prospective studies consider a great time to confirm these findings are required (AU)

[Factors associated with post-stroke oropharingeal dysphagia]. / Factores asociados a la disfagia orofaringea postictus.

INTRODUCTION: Neurogenic dysphagia is a consequence of stroke that sometimes threatens the patient's life. The magnitude of the brain damage commonly generated by stroke generates the emergence of other disorders that accompany dysphagia and worsen the patient's health. AIM: To analyze possible associations between communication disorders, disease factors, demographic factors and comorbidities with post-stroke dysphagia in years 2009 to 2011. PATIENTS AND METHODS: We studied 1519 medical records of patients that suffered stroke between 2009 and 2011. RESULTS: From medical records reviewed, 206 had dysphagia (13.6%). 80,1% from dysphagic patients had between 60 to 89 years old. 66% from them stayed hospitalized for more than 11 days. Age (odds ratio = 2.36; p < 0.001), aphasia (odds ratio = 4.47; p < 0.001), dysarthria (odds ratio = 4.95; p < 0.001), time of hospitalization (odds ratio = 3.65; p < 0.001) and hypertension (odds ratio = 1.64; p = 0.023) were statistically associated with dysphagia. Finally, 73,3% from dysphagic patients they had dysphagia with aphasia or dysarthria or apraxia of speech, however, 26,7% only had dysphagia. CONCLUSION: Neurogenic dysphagia seems to be associated with communication disorders, increase the time of hospitalization and associated with a hypertension. However, prospective studies consider a great time to confirm these findings are required.

TITLE: Factores asociados a la disfagia orofaringea postictus.Introduccion. La disfagia neurogena es una secuela del ictus que en ocasiones pone en riesgo la vida del paciente. La magnitud del daño cerebral generado por el ictus comunmente ocasiona la aparicion de otros trastornos que acompañan a la disfagia y agravan la salud del paciente. Objetivo. Analizar posibles asociaciones entre trastornos de la comunicacion, factores propios de la enfermedad, demograficos y comorbidos con disfagia en pacientes que sufrieron un ictus durante el ingreso hospitalario entre los años 2009 y 2011. Pacientes y metodos. Se estudiaron 1.519 historias clinicas de pacientes que presentaron ictus entre los años 2009 y 2011. Resultados. De los registros analizados, 206 presentaron disfagia (13,6%). El 80,1% de los casos de disfagia se concentro en pacientes de 60-89 años. El 66% de ellos permanecio hospitalizado durante mas de 11 dias. La edad (odds ratio = 2,36; p < 0,001), afasia (odds ratio = 4,47; p < 0,001), disartria (odds ratio = 4,95; p < 0,001), tiempo de hospitalizacion (odds ratio = 3,65; p < 0,001) e hipertension arterial (odds ratio = 1,64; p = 0,023) se asociaron estadisticamente con disfagia. Finalmente, en el 73,3% de los casos con disfagia, se presento disfagia mas afasia o disartria o apraxia del habla, mientras que solo el 26,7% tuvo exclusivamente disfagia. Conclusiones. La disfagia neurogena parece concomitar con trastornos de la comunicacion, aumentar el tiempo de hospitalizacion y asociarse a hipertension arterial. Sin embargo, se requieren estudios prospectivos que consideren un gran periodo de tiempo para confirmar estos hallazgos.