A dense ring of the trans-Neptunian object Quaoar outside its Roche limit.

Planetary rings are observed not only around giant planets1, but also around small bodies such as the Centaur Chariklo2 and the dwarf planet Haumea3. Up to now, all known dense rings were located close enough to their parent bodies, being inside the Roche limit, where tidal forces prevent material with reasonable densities from aggregating into a satellite. Here we report observations of an inhomogeneous ring around the trans-Neptunian body (50000) Quaoar. This trans-Neptunian object has an estimated radius4 of 555 km and possesses a roughly 80-km satellite5 (Weywot) that orbits at 24 Quaoar radii6,7. The detected ring orbits at 7.4 radii from the central body, which is well outside Quaoar's classical Roche limit, thus indicating that this limit does not always determine where ring material can survive. Our local collisional simulations show that elastic collisions, based on laboratory experiments8, can maintain a ring far away from the body. Moreover, Quaoar's ring orbits close to the 1/3 spin-orbit resonance9 with Quaoar, a property shared by Chariklo's2,10,11 and Haumea's3 rings, suggesting that this resonance plays a key role in ring confinement for small bodies.

Study of nitrogen implantation in Ti surface using plasma immersion ion implantation & deposition technique as biocompatible substrate for artificial membranes.

The present investigation reports the modification of Ti substrates by a plasma technique to enhance their physio-chemical properties as biocompatible substrates for the deposition of artificial membranes. For that purpose, nitrogen ions are implanted into Ti substrate using the plasma immersion ion implantation & deposition (PIII&D) technique in a capacitively coupled radio frequency plasma. The plasma was characterized using optical emission spectroscopy, together with radio frequency compensated Langmuir probe, while the ion current towards the substrate was measured during the implantation process using an opto-electronic device. X-ray photoelectron spectroscopy (XPS) was used for chemical analysis of the surface, confirming the presence of δ-TiN. The penetration depth of the nitrogen ions into the Ti substrate was measured using secondary ions mass spectroscopy (SIMS) while the morphological changes were observed using atomic force microscopy (AFM). A calorimetric assay was used to prove that the TiN samples maintain the biocompatibility of the untreated Ti surface with its native oxide layer. The ion implantation increases the load bearing ability of Ti surface by the formation of α-Ti(N) and δ-TiN phases on the sub-surface of Ti, and maintains the bio compatibility of Ti surface. After the plasma treatment a thin layer of chitosan (CH) was deposited in order to provide a moisturizing matrix for the artificial membrane of 1,2-dipalmitoyl-sn-3- phosphor glycerocholine (DPPC). The CH and subsequently the DPPC were deposited on the plasma deposited TiN substrate by using physical vapor deposition. The formation of artificial membranes was confirmed by AFM, measuring the topography at different temperatures and performing force curves.

A multiplanet system of super-Earths orbiting the brightest red dwarf star GJ 887.

The closet exoplanets to the Sun provide opportunities for detailed characterization of planets outside the Solar System. We report the discovery, using radial velocity measurements, of a compact multiplanet system of super-Earth exoplanets orbiting the nearby red dwarf star GJ 887. The two planets have orbital periods of 9.3 and 21.8 days. Assuming an Earth-like albedo, the equilibrium temperature of the 21.8-day planet is ~350 kelvin. The planets are interior to, but close to the inner edge of, the liquid-water habitable zone. We also detect an unconfirmed signal with a period of ~50 days, which could correspond to a third super-Earth in a more temperate orbit. Our observations show that GJ 887 has photometric variability below 500 parts per million, which is unusually quiet for a red dwarf.

Menopausal symptoms are associated with non-adherence to highly active antiretroviral therapy in human immunodeficiency virus-infected middle-aged women.

Objective: This study aimed to evaluate the association between the intensity of menopausal symptoms and highly active antiretroviral therapy (HAART) adherence in middle-aged women with human immunodeficiency virus (HIV) infection.Methods: In this cross-sectional study, 313 Peruvian women with HIV infection (age 40-59 years) were surveyed and classified as adherent or non-adherent to HAART based on the Antiretroviral Treatment Adherence Evaluation Questionnaire. The intensity of menopausal symptoms was assessed with the Menopause Rating Scale, and categorized as none, mild, moderate, and/or severe. Age, sexual orientation, used HAART scheme, time since HIV diagnosis, menopausal status, risk of depression, and presence of comorbidities were also assessed. Poisson generalized linear models with robust variance were performed in order to estimate crude prevalence ratios (PRs) and adjusted PRs using statistical (a1PR) and epidemiological criteria (a2PR).Results: A total of 19.9%, 32.6%, and 15.0% of all women presented mild, moderate, and severe menopausal symptoms, respectively. Overall, 70.6% women were non-adherent to HAART. The probability of non-adherence was higher in women with mild, moderate, and severe symptoms as compared to asymptomatic women in the non-adjusted model (PR: 1.79, 95% confidence interval [CI]: 1.39-2.29; PR: 1.76, 95% CI: 1.38-2.23; and PR: 2.07, 95% CI: 1.64-2.61, respectively) and the adjusted model.Conclusion: The severity of menopausal symptoms was associated with HAART non-adherence in HIV-infected middle-aged women.

Resultados a largo plazo de artroplastia de cadera en pacientes en diálisis por insuficiencia renal crónica. Mortalidad y supervivencia del implante en el Registro Nacional de Uruguay desde el año 2000 / Long-term results of hip arthroplasty in patients on dialysis for chronic renal failure. Mortality and implant survival in the National Registry of Uruguay since 2000

Objetivo: Evaluar la incidencia de mortalidad, revisión y valoración funcional en la artroplastia de cadera en pacientes dializados en Uruguay. Métodos: Se realizó un estudio observacional analítico de una cohorte histórica de artroplastias de cadera en pacientes con enfermedad renal crónica tratados con hemodiálisis o diálisis peritoneal entre el 1/1/2000 y el 31/12/2013; análisis de supervivencia mediante el método de Kaplan-Meier. Se realizó además, la evaluación funcional y radiológica de los pacientes vivos. Ciento cuarenta y una artroplastias de cadera, 42 por artrosis (29,8%) y 99 por fracturas (70,2%), edad 72,3 (DE: 12,1) años (18,9-93,1), 72 mujeres (51,1%) y 69 varones (48,9%), 75 artroplastias izquierdas (53,2%) y 66 derechas (46,8%). Predominó el abordaje anterolateral (115, 81,6%) respecto al posterolateral (26, 18,4%). Resultados: La mortalidad a los 30, 180 días, uno y 5 años en pacientes diagnosticados por artrosis fue del 2,4, 7,1, 9,5 y 47,6%, respectivamente, y en pacientes con fractura del 7,1, 18,2, 29,3 y 82,6%, respectivamente. Se realizaron 5 revisiones protésicas, 3 por luxación recidivante, una por aflojamiento aséptico y una artroplastia resección por infección. Doce pacientes estaban vivos al último control, la puntuación media según la escala de Merle D́Aubigne-Postel fue 6,4 en el preoperatorio y 11 al final del seguimiento. El índice de Barthel promedio en el seguimiento fue 72,8. Discusión: La mortalidad a mediano y largo plazo de estos pacientes fue muy alta, mucho mayor que la observada en los pacientes sometidos al mismo procedimiento que no están en diálisis. La revisión es excepcional, y la evaluación funcional de los pocos pacientes vivos muestra malos resultados clínico-radiológicos

Objective: To evaluate the incidence of mortality, revision and functional assessment after hip arthroplasty in dialysis patients in Uruguay. Methods: An observational analytical study of a historical cohort of hip arthroplasties was performed on patients with chronic kidney disease treated with haemodialysis or peritoneal dialysis between 1/1/2000-31/12/2013; survival analysis using the Kaplan-Meier method. Functional and radiological evaluation of the live patients was also carried out. One hundred and forty-one hip arthroplasties, 42 for osteoarthritis (29.8%) and 99 for fractures (70.2%), age 72.3 (SD: 12.1) years (18.9-93.1), 72 women (51.1%) and 69 men (48.9%), 75 left arthroplasties (53.2%) and 66 right (46.8%). The anterolateral approach (115, 81.6%) predominated over the posterolateral approach (26, 18.4%). Results: Mortality at 30, 180 days, 1 and 5 years of patients diagnosed with osteoarthritis was 2.4, 7.1, 9.5 and 47.6%, respectively, and of patients with fracture it was 7.1, 18.2, 29.3 and 82.6%. Five prosthetic revisions were performed, 3 due to recurrent dislocation, one due to aseptic loosening, and one resection arthroplasty due to infection. Twelve patients were alive at the last control, the average score according to the scale of Merle D'Aubigne-Postel was 6.4 preoperatively, and 11 at the end of the follow-up. The average Barthel index at follow-up was 72.8. Discussion: The mortality in the medium and long term of these patients was very high, much higher than that observed in patients undergoing the same procedure not on dialysis. The review is exceptional, and the functional evaluation of the few living patients shows poor clinical-radiological results

[Tensor fascia lata unilateral hypertrophy: A case report]. / Hipertrofia unilateral del músculo tensor de la fascia lata, a propósito de un caso.

Hypertrophy of the tensor fascia lata muscle is an uncommon clinical entity, which can simulate a soft tissue tumour. In most patients, it presents as a palpable proximal anterior thigh mass. The characteristic appearance on CT or MRI allows a confident diagnosis of muscle hypertrophy to be made, avoiding unnecessary diagnostic biopsy or surgical intervention. In cases with suspected radiculopathy, electromyography is also useful. We present an illustrative case of hypertrophy of the tensor fascia lata muscle and its outcome after rehabilitation treatment.

Long-term results of hip arthroplasty in patients on dialysis for chronic renal failure. Mortality and implant survival in the National Registry of Uruguay since 2000. / Resultados a largo plazo de artroplastia de cadera en pacientes en diálisis por insuficiencia renal crónica. Mortalidad y supervivencia del implante en el Registro Nacional de Uruguay desde el año 2000.

OBJECTIVE: To evaluate the incidence of mortality, revision and functional assessment after hip arthroplasty in dialysis patients in Uruguay. METHODS: An observational analytical study of a historical cohort of hip arthroplasties was performed on patients with chronic kidney disease treated with haemodialysis or peritoneal dialysis between 1/1/2000-31/12/2013; survival analysis using the Kaplan-Meier method. Functional and radiological evaluation of the live patients was also carried out. One hundred and forty-one hip arthroplasties, 42 for osteoarthritis (29.8%) and 99 for fractures (70.2%), age 72.3 (SD: 12.1) years (18.9-93.1), 72 women (51.1%) and 69 men (48.9%), 75 left arthroplasties (53.2%) and 66 right (46.8%). The anterolateral approach (115, 81.6%) predominated over the posterolateral approach (26, 18.4%). RESULTS: Mortality at 30, 180 days, 1 and 5 years of patients diagnosed with osteoarthritis was 2.4, 7.1, 9.5 and 47.6%, respectively, and of patients with fracture it was 7.1, 18.2, 29.3 and 82.6%. Five prosthetic revisions were performed, 3 due to recurrent dislocation, one due to aseptic loosening, and one resection arthroplasty due to infection. Twelve patients were alive at the last control, the average score according to the scale of Merle D'Aubigne-Postel was 6.4 preoperatively, and 11 at the end of the follow-up. The average Barthel index at follow-up was 72.8. DISCUSSION: The mortality in the medium and long term of these patients was very high, much higher than that observed in patients undergoing the same procedure not on dialysis. The review is exceptional, and the functional evaluation of the few living patients shows poor clinical-radiological results.

Hipertrofia unilateral del músculo tensor de la fascia lata, a propósito de un caso / Tensor fascia lata unilateral hypertrophy: a case report

La hipertrofia del músculo tensor de la fascia lata es una entidad clínica poco frecuente que puede simular un tumor de partes blandas. En la mayoría de los pacientes se presenta como una masa anterior palpable en la cara proximal del muslo. La imagen característica en la TC o la RMN es diagnóstica, evitando la realización de biopsia o intervenciones quirúrgicas. En los casos donde se sospeche radiculopatía también es de utilidad el electromiograma. Presentamos un caso clínico y su evolución con tratamiento rehabilitador

Hypertrophy of the tensor fascia lata muscle is an uncommon clinical entity, which can simulate a soft tissue tumour. In most patients, it presents as a palpable proximal anterior thigh mass. The characteristic appearance on CT or MRI allows a confident diagnosis of muscle hypertrophy to be made, avoiding unnecessary diagnostic biopsy or surgical intervention. In cases with suspected radiculopathy, electromyography is also useful. We present an illustrative case of hypertrophy of the tensor fascia lata muscle and its outcome after rehabilitation treatment

Tamoxifen induces apoptotic neutrophil efferocytosis in horses.

Macrophages and neutrophils are important cellular components in the process of acute inflammation and its subsequent resolution, and evidence increasingly suggests that they play important functions during the resolution of chronic, adaptive inflammatory processes. Exacerbated neutrophil activity can be harmful to surrounding tissues; this is important in a range of diseases, including allergic asthma and chronic obstructive pulmonary disease in humans, and equine asthma (also known as recurrent airway obstruction (RAO). Tamoxifen (TX) is a non-steroidal estrogen receptor modulator with effects on cell growth and survival. Previous studies showed that TX treatment in horses with induced acute pulmonary inflammation promoted early apoptosis of blood and BALF neutrophils, reduction of BALF neutrophils, and improvement in animals' clinical status. The aim of this study was to describe if TX induces in vitro efferocytosis of neutrophils by alveolar macrophages. Efferocytosis assay, myeloperoxidase (MPO) detection and translocation phosphatidylserine (PS) were performed on neutrophils isolated from peripheral blood samples from five healthy horses. In in vitro samples from heathy horses, TX treatment increases the phenomenon of efferocytosis of peripheral neutrophils by alveolar macrophages. Similar increases in supernatant MPO concentration and PS translocation were observed in TX-treated neutrophils, compared to control cells. In conclusion, these results confirm that tamoxifen has a direct effect on equine peripheral blood neutrophils, through stimulation of the engulfment of apoptotic neutrophils by alveolar macrophages.

The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation.

Haumea-one of the four known trans-Neptunian dwarf planets-is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo's rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea's equator and the orbit of its satellite Hi'iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea's spin period-that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea's largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

Síndrome de Baxter, a propósito de un caso / Baxter syndrome: a case report

El síndrome de Baxter consiste en una neuropatía por atrapamiento de la primera rama del nervio plantar lateral o calcáneo inferior que cursa con dolor, imposibilidad para la abducción del 5.° dedo y, en algunos casos, parestesias. Se presenta el caso de una paciente de 44 años diagnosticada de fascitis plantar, tratada quirúrgicamente con fasciectomía tras el fracaso del tratamiento conservador. Durante el postoperatorio presentó pérdida de la movilidad del 5.° dedo, parestesias difusas y dolor moderado con dificultad para la deambulación. Tras la realización de resonancia magnética y electromiograma es diagnosticada de síndrome de Baxter. Inició tratamiento de rehabilitación obteniendo mejoría de la alodinia a nivel de la cicatriz y adquirió marcha sin ayudas técnicas, con menor dificultad para puntillas y talones. Sin embargo mantuvo parestesias ocasionales y ausencia de movilidad del 5º dedo (AU)

Baxter syndrome is an entrapment neuropathy of the first branch of the lateral plantar nerve or inferior calcaneal nerve that causes pain, inability to abduct the fifth toe and, in some cases, paraesthesia. We report the case of a 44-year-old woman with a diagnosis of plantar fasciitis, treated surgically with fasciectomy after failure of conservative treatment. During the postoperative period, the patient showed loss of mobility of the fifth toe, moderate diffuse pain, numbness, and difficulty walking. After the performance of magnetic resonance imaging and electromyography, the patient was diagnosed with Baxter syndrome. She began rehabilitation, which improved allodynia of the scar and allowed her to walk without technical aids and with less difficulty in heel toe walking. However, there was persistence of occasional numbness and lack of mobility of the fifth toe (AU)

Oxidative and endoplasmic reticulum stress is impaired in leukocytes from metabolically unhealthy vs healthy obese individuals.

BACKGROUND: Oxidative stress and inflammation are related to obesity, but the influence of metabolic disturbances on these parameters and their relationship with endoplasmic reticulum (ER) stress is unknown. Therefore, this study was performed to evaluate whether metabolic profile influences ER and oxidative stress in an obese population with/without comorbidities. SUBJECTS AND METHODS: A total of 113 obese patients were enrolled in the study; 29 were metabolically healthy (MHO), 53 were metabolically abnormal (MAO) and 31 had type 2 diabetes (MADO). We assessed metabolic parameters, proinflammatory cytokines (TNFα and IL-6), mitochondrial and total reactive oxygen species (ROS) production, glutathione levels, antioxidant enzymes activity, total antioxidant status, mitochondrial membrane potential and ER stress marker expression levels (glucose-regulated protein (GRP78), spliced X-box binding protein 1 (XBP1), P-subunit 1 alpha (P-eIF2α) and activating transcription factor 6 (ATF6). RESULTS: The MAO and MADO groups showed higher blood pressure, atherogenic dyslipidemia, insulin resistance and inflammatory profile than that of MHO subjects. Total and mitochondrial ROS production was enhanced in MAO and MADO patients, and mitochondrial membrane potential and catalase activity differed significantly between the MADO and MHO groups. In addition, decreases in glutathione levels and superoxide dismutase activity were observed in the MADO vs MAO and MHO groups. GRP78 and CHOP protein and gene expression were higher in the MAO and MADO groups with respect to MHO subjects, and sXBP1 gene expression was associated with the presence of diabetes. Furthermore, MAO patients exhibited higher levels of ATF6 than their MHO counterparts. Waist circumference was positively correlated with ATF6 and GRP78, and A1c was positively correlated with P-Eif2α. Interestingly, CHOP was positively correlated with TNFα and total ROS production and GRP78 was negatively correlated with glutathione levels. CONCLUSIONS: Our findings support the hypothesis that both inflammation and oxidative stress are involved in the induction of ER stress signaling pathways in the leukocytes of metabolically unhealthy obese vs healthy obese subjects.

Lagrangian 3D tracking of fluorescent microscopic objects in motion.

We describe the development of a tracking device, mounted on an epi-fluorescent inverted microscope, suited to obtain time resolved 3D Lagrangian tracks of fluorescent passive or active micro-objects in microfluidic devices. The system is based on real-time image processing, determining the displacement of a x, y mechanical stage to keep the chosen object at a fixed position in the observation frame. The z displacement is based on the refocusing of the fluorescent object determining the displacement of a piezo mover keeping the moving object in focus. Track coordinates of the object with respect to the microfluidic device as well as images of the object are obtained at a frequency of several tenths of Hertz. This device is particularly well adapted to obtain trajectories of motile micro-organisms in microfluidic devices with or without flow.

Enhancement of struvite pellets crystallization in a full-scale plant using an industrial grade magnesium product.

A full-scale struvite crystallization system was operated for the treatment of the centrate obtained from the sludge anaerobic digester in a municipal wastewater treatment plant. Additionally, the feasibility of an industrial grade Mg(OH)2 as a cheap magnesium and alkali source was also investigated. The struvite crystallization plant was operated for two different periods: period I, in which an influent with low phosphate concentration (34.0 mg P·L-1) was fed to the crystallization plant; and period II, in which an influent with higher phosphate concentration (68.0 mg P·L-1) was used. A high efficiency of phosphorus recovery by struvite crystallization was obtained, even when the effluent treated had a high level of alkalinity. Phosphorus recovery percentage was around 77%, with a phosphate concentration in the effluent between 10.0 and 30.0 mg P·L-1. The experiments gained struvite pellets of 0.5-5.0 mm size. Moreover, the consumption of Mg(OH)2 was estimated at 1.5 mol Mg added·mol P recovered-1. Thus, industrial grade Mg(OH)2 can be an economical alternative as magnesium and alkali sources for struvite crystallization at industrial scale.

In Vitro effects of tamoxifen on equine neutrophils.

Neutrophils participate in innate immunity as the first line of host defense against microorganisms. However, exacerbated neutrophil activity can be harmful to surrounding tissues; this is important in a range of diseases, including allergic asthma and chronic obstructive pulmonary disease in humans, and equine asthma (also known as recurrent airway obstruction (RAO). Tamoxifen (TX) is a non-steroidal estrogen receptor modulator with effects on cell growth and survival. Previous preliminary studies showed that TX treatment in horses with induced acute pulmonary inflammation promoted early apoptosis of blood and BALF neutrophils, reduction of BALF neutrophils, and improvement in animals' clinical status. The aim of this study was to evaluate the in vitro effect of TX on functional tests in equine peripheral blood neutrophils. Chemotaxis, respiratory burst production and phagocytosis assays were performed on neutrophils isolated from peripheral blood samples from 10 healthy horses. Results showed that IL-8 stimulated cells decrease their chemotactic index when treated with TX (1 and 10µM). Respiratory burst production was also dampened after treatment with TX. In conclusion, these results confirm that tamoxifen has a direct action on equine peripheral blood neutrophils. However, more in vivo and in vitro studies are required to fully understand the mechanisms of action of TX on neutrophils, in order to elucidate if it can be used as treatment in disorders such as allergic asthma in humans and horses.

Características psicométricas de la versión española de la escala UWES-S en estudiantes universitarios de Fisioterapia / Psychometrics of the Spanish version of the UWES-S scale in Physiotherapy college students

Objetivo: Esta investigación tiene como objetivo primordial comprobar la utilidad y aplicabilidad del cuestionario Utrecht Work Engagement Scale for Students (UWES-S) para la medición del compromiso o engagement académico en estudiantes universitarios de Fisioterapia. Metodología: La muestra está compuesta por 79 estudiantes universitarios (55 mujeres y 24 varones) que cumplimentaron voluntariamente el cuestionario. Se efectuó un análisis de los ítems a través del índice de homogeneidad, se estudió su validez de constructo a través de la estructura factorial y se comprobó la fiabilidad de la escala mediante el análisis de su consistencia interna. Resultados: Los resultados obtenidos indican que todos los ítems son significativamente homogéneos. La consistencia interna oscila entre 0,74 y 0,87. Del análisis factorial por el método de componentes principales y posterior rotación oblimin se extrajeron un total de 3 factores que explican el 65,26% de la varianza de los datos. Se han observado algunas variaciones en la agrupación de los ítems, por lo que se plantea un modelo alternativo. Conclusiones: En general, los resultados son coherentes y considerablemente similares, con sus excepciones, a los obtenidos por otros autores en otros grupos universitarios, por lo que apoyan la utilización de esta herramienta como instrumento válido de evaluación del engagement académico en estudiantes universitarios de Fisioterapia

Background: The purpose of this research was to examine the Spanish version of the Utrecht Work Engagement Scale for Students (UWES-S) in order to analyze if it can be considered as a suitable and useful tool in Physiotherapy students. Method: A sample of 79 college students was recruited (55 women and 24 men) to voluntarily complete the questionnaire. Item analysis was carried out by means of homogeneity index, construct validity was measured with factorial structure and reliability of the scale was put to test by analyzing its internal consistency. Results: Results showed all items are significantly homogeneous. Internal consistency ranges between 0.74 and 0.87. Factorial analysis using principal components analysis and subsequent oblimin rotation reveal a total of 3 factors explaining 65.26% of data variance. Some differences in the organization of the items has been observed, therefore and an alternative model is proposed. Conclusions: On the whole, these results are very similar, despite some exceptions, to those reported by other authors in different college groups. The Spanish version of the UWES-S is found acceptable for engagement assessment at Physiotherapy college students

Transmission dynamics of two dengue serotypes with vaccination scenarios.

In this work we present a mathematical model that incorporates two Dengue serotypes. The model has been constructed to study both the epidemiological trends of the disease and conditions that allow coexistence in competing strains under vaccination. We consider two viral strains and temporary cross-immunity with one vector mosquito population. Results suggest that vaccination scenarios will not only reduce disease incidence but will also modify the transmission dynamics. Indeed, vaccination and cross immunity period are seen to decrease the frequency and magnitude of outbreaks but in a differentiated manner with specific effects depending upon the interaction vaccine and strain type.

Bacterial community dynamics in long-term operation of a pilot plant using aerobic granular sludge to treat pig slurry.

Aerobic granular sludge represents an interesting approach for simultaneous organic matter and nitrogen removal in wastewater treatment plants. However, the information about microbial communities in aerobic granular systems dealing with industrial wastewater like pig slurry is limited. Herein, bacterial diversity and dynamics were assessed in a pilot scale plant using aerobic granular sludge for organic matter and nitrogen elimination from swine slurry during more than 300 days. Results indicated that bacterial composition evolved throughout the operational period from flocculent activated sludge, used as inoculum, to mature aerobic granules. Bacterial diversity increased at the beginning of the granulation process and then declined due to the application of transient organic matter and nitrogen loads. The operational conditions of the pilot plant and the degree of granulation determined the microbial community of the aerobic granules. Brachymonas, Zoogloea and Thauera were attributed with structural function as they are able to produce extracellular polymeric substances to maintain the granular structure. Nitrogen removal was justified by partial nitrification (Nitrosomonas) and denitrification (Thauera and Zoogloea), while Comamonas was identified as the main organic matter oxidizing bacteria. Overall, clear links between bacterial dynamics and composition with process performance were found and will help to predict their biological functions in wastewater ecosystems improving the future control of the process. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1212-1221, 2016.

Influence of dissolved oxygen concentration on the start-up of the anammox-based process: ELAN®.

The anammox-based process ELAN® was started-up in two different sequencing batch reactor (SBR) pilot plant reactors treating municipal anaerobic digester supernatant. The main difference in the operation of both reactors was the dissolved oxygen (DO) concentration in the bulk liquid. SBR-1 was started at a DO value of 0.4 mg O2/L whereas SBR-2 was started at DO values of 3.0 mg O2/L. Despite both reactors working at a nitrogen removal rate of around 0.6 g N/(L d), in SBR-1, granules represented only a small fraction of the total biomass and reached a diameter of 1.1 mm after 7 months of operation, while in SBR-2 the biomass was mainly composed of granules with an average diameter of 3.2 mm after the same operational period. Oxygen microelectrode profiling revealed that granules from SBR-2 where only fully penetrated by oxygen with DO concentrations of 8 mg O2/L while granules from SBR-1 were already oxygen penetrated at DO concentrations of 1 mg O2/L. In this way granules from SBR-2 performed better due to the thick layer of ammonia oxidizing bacteria, which accounted for up to 20% of all the microbial populations, which protected the anammox bacteria from non-suitable liquid media conditions.