High temperature behaviour of CuO-based oxygen carriers for chemical-looping combustion process

El “Chemical Looping Combustion” (CLC) es una tecnología de combustión con separación inherente del CO2. Para escalar el proceso se necesitan materiales aptos para trabajar a alta temperatura. Se ha probado que los transportadores de base cobre cumplen los requerimientos, sin embargo se ha recomendado su trabajo a temperaturas menores de 1073 K. En este trabajo, se han desarrollado, por impregnación en diferentes soportes, dos transportadores basados en Cu. Se estudió su comportamiento a temperaturas por encima de 1073K en una unidad de CLC de 500 Wth teniendo en cuenta aspectos como: eficiencia de combustión, resistencia al desgaste, aglomeración, mantenimiento de la capacidad de transporte de oxígeno y reactividad. Problemas de aglomeración o desactivación de las partículas no se detectaron con ninguno de los TOs. Fue posible la operación estable durante más de 67 horas sólo con el TO modificado con la adición de NiO como soporte. Esta es la primera vez que un TO de base cobre, preparado por un método de fabricación comercial, se utiliza a 1173 K de temperatura en el reactor de reducción (TRR) y 1223 K en el de oxidación (TRO) y presenta buenas propiedades, abriendo nuevas posibilidades para la aplicación de materiales a base de cobre en los procesos de CLC a escala industrial. Abstract Chemical-Looping Combustion (CLC) is a combustion technology with inherent CO2 separation. To scale up the CLC process materials suitable to work at high temperatures are needed. Cu-based oxygen carriers had been proved to fulfil the requirements although temperatures lower than 1073 K has been recommended. In this work, two Cu-based OCs have been developed by impregnation on different supports. The behaviour of the OCs was studied at temperatures above 1073K in a CLC continuous unit of 500 Wth taking into account aspects such as combustion efficiency, attrition, agglomeration and maintenance of the oxygen transport capacity and reactivity. Agglomeration or deactivation of the particles was never detected with neither of the oxygen carriers used. At these high temperatures, stable operation for more than 67 h was feasible only using an OC with γAl2O3 modified with NiO addition as support. This is the first time that a Cu-based OC, prepared by a commercial manufacturing method, and used at 1173 K of fuel reactor temperature (TFR) and 1223 K of air reactor temperature (TAR) exhibits such a good properties. This result opens new possibilities for the application of Cu-based materials in industrial-scale CLC processes

Effect of force angle on the strain distribution of osseointegrated dental implants

International audienceIn this work, we investigate the response of the anisotropic maxilla bone in the peri-implant region, when osseointegrated implants are subjected to external forces at different angles, based on the stress and strain distribution by the finite element method. Models were created to represent a portion of a maxilla bone (upper first molar region) with two types of implants which have different thread geometry (squared and V-shaped) and material (Ti-6AL-4V ELI and grade IV Titanium). Compressive axial (150 N) and oblique load (150 N at 45° angle) were applied to anisotropic models of the bone tissues. Complete osseointegration was assumed. Results demonstrated that the increase of the implant inclination leads to a more critical behaviour. Oblique loading is more detrimental to stress and strain distribution than axial load. Stress fields were more efficiently distributed by squared thread implants

Prevalencia de trematodes y factores de riesgo asociados con el ganado lechero en Colombia

This study was conducted to establish the prevalence and identify the risk factors associated with trematode infections in dairy cattle in the Boyacá Highlands, Colombia. Fecal samples collected from 300 randomly selected cattle were examined using a simple sedimentation technique for differential trematodes egg count. The animals were found shedding eggs of three groups of trematodes, namely Fasciola hepatica, Paramphistomum cervi and Cotylophoron cotylophorum. The specific prevalence of this trematodes were 11.6%, 9.3%, and 3.7% respectively. A substantial overlap was observed in the appearance of F. hepatica y P. cervi. The prevalence of the three trematodes identified in this study was significantly associated (p<0.05) with body condition and breed, while the prevalence of Fasciola hepatica and Paramphistomum cervi, was associated with age. The prevalence of the three main trematodes of importance for animal health with a high rate of mixed infection along with a poor body condition, suggests a substantial economic loss incurred due to reduced productivity of livestock in the study area.El estudio se llevó a cabo para establecer la prevalencia e identificar los factores de riesgo asociados con las infecciones por trematodes en ganado lechero de las tierras altas de Boyacá, Colombia. Las muestras fecales recogidas de 300 bovinos seleccionados al azar se examinaron utilizando una técnica de sedimentación simple para el recuento diferencial de huevos de trematodes. En el ganado estudiado fueron encontrados huevos de tres grupos de trematodes, a saber: Fasciola hepatica, Paramphistomum cervi y Cotylophoron cotylophorum. La prevalencia específica para estas tres especies fueron de 11,6%, 9,3% y 3,7% respectivamente. Se observó una superposición importante entre F. hepatica y P. cervi. La prevalencia de los tres trematodes identificados en este estudio se asoció significativamente (p<0,05) con la condición corporal y la raza, mientras que la prevalencia de Fasciola sp y Paramphistomum sp fue asociada con la edad. La prevalencia de los tres principales trematodes de importancia para la salud animal y la alta tasa de infección mixta, junto al deterioro de la condición corporal, determinan una pérdida económica sustancial debida a la reducción de la productividad del ganado en el área estudiada

The association of Emergency Department presentations in pregnancy with hospital admissions for postnatal depression (PND): a cohort study based on linked population data

BACKGROUND: To investigate the impact of presenting to an Emergency Department (ED) during pregnancy on postnatal depression (PND) in women in New South Wales (NSW), Australia.METHOD: An epidemiological population-based study using linked data from the NSW Emergency Department Data Collection (EDDC), the NSW Perinatal Data Collection (PDC) and the NSW Admitted Patients Data Collection (APDC) was conducted. Women who gave birth to their first child in NSW between 1 January 2006 and 31 December 2010 were followed up from pregnancy to the end of the first year after birth.RESULTS: The study population includes 154,328 women who gave birth to their first child in NSW between 2006 and 2010. Of these, 31,764 women (20.58%) presented to ED during pregnancy (95%CI = 20.38-20.78). Women who presented to ED during pregnancy were more likely to be admitted to hospital for the diagnosis of unipolar depression (the adjusted relative risk (RR) =1.86, 95%CI = 1.49-2.31) and the diagnosis of mild mental and behavioural disorders associated with the puerperium (the adjusted RR = 1.55, 95%CI = 1.29-1.87) than those without ED presentation.CONCLUSION: Women's hospital admissions for postnatal depression were associated with frequent ED presentations during pregnancy

Evaluation of additional head of biceps brachii: a study with autopsy material

Additional head of the biceps brachii (AHBB) has been reported in different population groups with a frequency of 1–25%. The purpose of this study was to determine the incidence and morphologic expression of the AHBB as determined in a sample of the Colombian population. An exploration was conducted with 106 arms corresponding to unclaimed corpses autopsied at Institute of Legal and Forensic Medicine of Bucaramanga, Colombia. Using medial incision involvingskin, subcutaneous tissue, and brachial fascia, the heads of the biceps and their innervating branches were visualised. One AHBB was observed in 21 (19.8%) of the arms evaluated, with non-significant difference (p = 0.568) per side of presentation: 11 (52.4%) cases on the right side and 10 (47.6%) on the left side. All AHBBs were originated in the infero-medial segment of the humerus, with a mean thickness of 17.8 ± 6.8 mm. In 4 (19%) cases the fascicle was thin, less than 10 mm; in 7 (33.3%) cases it was of medium thickness, between 11 and 20 mm, whereas in 47.6% it was longer than 20 mm. The length of the AHBB was 118.3 ± 26.8 mm; its motor point supplied by the musculocutaneous nerve was located at 101.3 ± 20.9 mm of the bi-epicondylar line. The incidence of AHBB in this study is located at the upper segment of what has been reportedin the literature and could be a morphologic trait of the Colombian population; in agreement with prior studies, the origin was the infero-medial surface of the humerus

El cultivo del maíz y del sorgo en Colombia costos de producción y rentabilidad.

Maíz-Zea maysSorgo-sorgos - Sorghum bicolo

Thermoresponsive Ionic Liquid/Water Mixtures: From Nanostructuring to Phase Separation

The thermodynamics, structures, and applications of thermoresponsive systems, consisting primarily of water solutions of organic salts, are reviewed. The focus is on organic salts of low melting temperatures, belonging to the ionic liquid (IL) family. The thermo-responsiveness is represented by a temperature driven transition between a homogeneous liquid state and a biphasic state, comprising an IL-rich phase and a solvent-rich phase, divided by a relatively sharp interface. Demixing occurs either with decreasing temperatures, developing from an upper critical solution temperature (UCST), or, less often, with increasing temperatures, arising from a lower critical solution temperature (LCST). In the former case, the enthalpy and entropy of mixing are both positive, and enthalpy prevails at low T. In the latter case, the enthalpy and entropy of mixing are both negative, and entropy drives the demixing with increasing T. Experiments and computer simulations highlight the contiguity of these phase separations with the nanoscale inhomogeneity (nanostructuring), displayed by several ILs and IL solutions. Current applications in extraction, separation, and catalysis are briefly reviewed. Moreover, future applications in forward osmosis desalination, low-enthalpy thermal storage, and water harvesting from the atmosphere are discussed in more detail

Characterizing SL2S galaxy groups using the Einstein radius

We analyzed the Einstein radius, $\theta_E$, in our sample of SL2S galaxy groups, and compared it with $R_A$ (the distance from the arcs to the center of the lens), using three different approaches: 1.- the velocity dispersion obtained from weak lensing assuming a Singular Isothermal Sphere profile ($\theta_{E,I}$), 2.- a strong lensing analytical method ($\theta_{E,II}$) combined with a velocity dispersion-concentration relation derived from numerical simulations designed to mimic our group sample, 3.- strong lensing modeling ($\theta_{E,III}$) of eleven groups (with four new models presented in this work) using HST and CFHT images. Finally, $R_A$ was analyzed as a function of redshift $z$ to investigate possible correlations with L, N, and the richness-to-luminosity ratio (N/L). We found a correlation between $\theta_{E}$ and $R_A$, but with large scatter. We estimate $\theta_{E,I}$ = (2.2 $\pm$ 0.9) + (0.7 $\pm$ 0.2)$R_A$, $\theta_{E,II}$ = (0.4 $\pm$ 1.5) + (1.1 $\pm$ 0.4)$R_A$, and $\theta_{E,III}$ = (0.4 $\pm$ 1.5) + (0.9 $\pm$ 0.3)$R_A$ for each method respectively. We found a weak evidence of anti-correlation between $R_A$ and $z$, with Log$R_A$ = (0.58$\pm$0.06) - (0.04$\pm$0.1)$z$, suggesting a possible evolution of the Einstein radius with $z$, as reported previously by other authors. Our results also show that $R_A$ is correlated with L and N (more luminous and richer groups have greater $R_A$), and a possible correlation between $R_A$ and the N/L ratio. Our analysis indicates that $R_A$ is correlated with $\theta_E$ in our sample, making $R_A$ useful to characterize properties like L and N (and possible N/L) in galaxy groups. Additionally, we present evidence suggesting that the Einstein radius evolves with $z$.Comment: Accepted for publication in Astronomy & Astrophysics. Typos correcte

Análisis probit generalizado.

Discute el tratamiento estadístico para estimar los parámetros en un modelo con respuesta dicotómica. Tales modelos ocurren con frecuencia en problemas econométricos. Constituyen valioso auxiliar para el econometrista, quien al examinar una población dada, observa una clasificación de sus elementos en 2 categorías. Los modelos dicotómicos de tan sencilla estructura han sido poco comprendidos por los investigadores. Su uso ha resultado complicado debido fundamentalmente a las complejidades aritméticas derivadas de su aplicación. Sin embargo, las ventajas que representan los medios de cómputo eléctronico, son razón poderosa para obviar tales dificultades. La descripción del Método probit de estimación es la aplicación del método de máxima verosimilitud al modelo dicotómico transformado, de acuerdo con la transformación Probit. El problema resultante es el clásico de estimación nolineal. Las ecuaciones normales tienen que resolverse por aproximaciones sucesivas. Se ilustra el proceso iteractivo de solución del sistema de ecuaciones normales derivadas del modelo. Se establecen adicionalmente los criterios de prueba aproximados objeto de la atención del investigador. El énfasis que se hace con respecto a la aplicación del Método probit, es ampliamente justificado: si el modelo hipotético es razonable, las estimaciones de máxima verosimilitud son suficientes para los parámetros, siendo además, asintóticamente eficiente

Utility of patient-derived lymphoblastoid cell lines as an ex vivo capecitabine sensitivity prediction model for breast cancer patients.

Capecitabine is commonly used in treating breast cancer; however, therapeutic response varies among patients and there is no clinically validated model to predict individual outcomes. Here, we investigated whether drug sensitivity quantified in ex vivo patients' blood-derived cell lines can predict response to capecitabine in vivo. Lymphoblastoid cell lines (LCLs) were established from a cohort of metastatic breast cancer patients (n = 53) who were prospectively monitored during treatment with single agent capecitabine at 2000 mg/m2/day. LCLs were treated with increasing concentrations of 5'-DFUR, a major capecitabine metabolite, to assess patients' ex vivo sensitivity to this drug. Subsequently, ex vivo phenotype was compared to observed patient disease response and drug induced-toxicities. We acquired an independent cohort of breast cancer cell lines and LCLs derived from the same donors from ATCC, compared their sensitivity to 5'-DFUR. As seen in the patient population, we observed large inter-individual variability in response to 5'-DFUR treatment in patient-derived LCLs. Patients whose LCLs were more sensitive to 5'-DFUR had a significantly longer median progression free survival (9-month vs 6-month, log rank p-value = 0.017). In addition, this significant positive correlation for 5'-DFUR sensitivity was replicated in an independent cohort of 8 breast cancer cell lines and LCLs derived from the same donor. Our data suggests that at least a portion of the individual sensitivity to capecitabine is shared between germline tissue and tumor tissue. It also supports the utility of patient-derived LCLs as a predictive model for capecitabine treatment efficacy in breast cancer patients