Clasificación de variables y reconciliación de datos en ingeniería de procesos

Las medidas de proceso de las plantas térmicas se utilizan para tareas de control, evaluación de rendimientos, optimización de la operación, etc. Frecuentemente se dispone de más medidas que las necesarias. La reconciliación consiste en ajustar las medidas redundantes de modo que obedezcan las leyes de conservación y cualquier otra restricción que incorpore el modelo matemático de la planta. Como resultado: (i) se detectan y eliminan los errores sistemáticos de medida; (ii) se obtiene un conjunto consistente de medidas ajustadas; (iii) se estiman las variables no medidas por el método de máxima verosimilitud y (iv) se obtienen intervalos de confianza para los resultados. En este trabajo se propone el método de la descomposición QR para analizar, descomponer y resolver los problemas de reconciliación lineal. Los problemas de reconciliación no lineal pueden resolverse iterativamente linealizando las ecuaciones del modelo matemático. Se presenta un ejemplo para ilustrar la aplicación de los procedimientos de cálculo propuestos.Peer Reviewe

Marginalization of Regression-Adjusted Treatment Effects in Indirect Comparisons with Limited Patient-Level Data

Population adjustment methods such as matching-adjusted indirect comparison (MAIC) are increasingly used to compare marginal treatment effects when there are cross-trial differences in effect modifiers and limited patient-level data. MAIC is sensitive to poor covariate overlap and cannot extrapolate beyond the observed covariate space. Current outcome regression-based alternatives can extrapolate but target a conditional treatment effect that is incompatible in the indirect comparison. When adjusting for covariates, one must integrate or average the conditional estimate over the population of interest to recover a compatible marginal treatment effect. We propose a marginalization method based on parametric G-computation that can be easily applied where the outcome regression is a generalized linear model or a Cox model. In addition, we introduce a novel general-purpose method based on multiple imputation, which we term multiple imputation marginalization (MIM) and is applicable to a wide range of models. Both methods can accommodate a Bayesian statistical framework, which naturally integrates the analysis into a probabilistic framework. A simulation study provides proof-of-principle for the methods and benchmarks their performance against MAIC and the conventional outcome regression. The marginalized outcome regression approaches achieve more precise and more accurate estimates than MAIC, particularly when covariate overlap is poor, and yield unbiased marginal treatment effect estimates under no failures of assumptions. Furthermore, the marginalized regression-adjusted estimates provide greater precision and accuracy than the conditional estimates produced by the conventional outcome regression, which are systematically biased because the measure of effect is non-collapsible

Derecho y poder en el destino de Crimea

Sumario: 1. Obertura Crimea. 2. Ortodoxia y Levedad en Naciones Unidas. 3. Sanciones de la comunidad occidental. 4. Impotencia e irredentismo ucraniano. 5. Haciendo política de bloques con los derechos humanos. 6. También en las Naciones Unidas. 7. El frente judicial. 8. ¿A quién importa los derechos humanos? 9. A modo de reflexión final

Improvement of imiquimod solubilization and skin retention via tpgs micelles: Exploiting the co-solubilizing effect of oleic acid

Imiquimod (IMQ) is an immunostimulant drug approved for the topical treatment of actinic keratosis, external genital-perianal warts as well as superficial basal cell carcinoma that is used off-label for the treatment of different forms of skin cancers, including some malignant melanocytic proliferations such as lentigo maligna, atypical nevi and other in situ melanoma-related diseases. Imiquimod skin delivery has proven to be a real challenge due to its very low water-solubility and reduced skin penetration capacity. The aim of the work was to improve the drug solubility and skin retention using micelles of d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), a water-soluble derivative of vitamin E, co-encapsulating various lipophilic compounds with the potential ability to improve imiquimod affinity for the micellar core, and thus its loading into the nanocarrier. The formulations were characterized in terms of particle size, zeta potential and stability over time and micelles performance on the skin was evaluated through the quantification of imiquimod retention in the skin layers and the visualization of a micelle-loaded fluorescent dye by two-photon microscopy. The results showed that imiquimod solubility strictly depends on the nature and concentration of the co-encapsulated compounds. The micellar formulation based on TPGS and oleic acid was identified as the most interesting in terms of both drug solubility (which was increased from few µg/mL to 1154.01 ± 112.78 µg/mL) and micellar stability (which was evaluated up to 6 months from micelles preparation). The delivery efficiency after the application of this formulation alone or incorporated in hydrogels showed to be 42-and 25-folds higher than the one of the commercial creams

Quantification of ochratoxin A and five analogs in Navarra red wines

Ochratoxin A (OTA), B (OTB) and their methyl (MeOTA, MeOTB) and ethyl (OTC, EtOTB) esters were evaluated in 51 red wine samples from Navarra (Spain). Detectable levels of OTA and OTB were found in 100% of the samples, and 71% showed the presence of OTC. The six ochratoxins appeared simultaneously in 18% of the samples. Results indicated that OTC is hydrolyzed to OTA in red wine. Therefore, ochratoxin intake from wine can be underestimated when only assessed by OTA analysis. Analyzed Navarra wines are scarcely contaminated with ochratoxins and their contribution to human intake is low, with the worst case being 4.7% and 6.6% of the provisional tolerable weekly intake (PTWI) for OTA and for the sum of ochratoxins, respectively. No significant differences were generally found between vintages. With the exception of OTA, no significant differences were observed between organic and traditional farming. Levels of ochratoxins were positively correlated with temperature and inversely correlated with humidity and rainfall

Levels of ochratoxins in Mediterranean red wines

The co-occurrence of ochratoxin A (OTA) and its five analogs (OTB, OTC, MeOTA, MeOTB and EtOTB) in 96 red wine samples from Mediterranean countries has been demonstrated, for the first time, in this study. OTA was detected in 99 % of the samples (<LOD-455 ng·L-1). This mycotoxin appeared simultaneously with OTB (2.05 - 119 ng·L-1) in all the samples and in 89.6% of them OTC (<LOD - 31.5 ng·L-1) also accompanied both. OTB appears at comparable levels and incidence just like OTA does, and OTC median concentration is approximately 10 % of that of OTA. A high statistical association was found between the concentrations of OTA-OTB and OTA-OTC. MeOTA, MeOTB and EtOTB were detected in 62.5, 83.3 and 83.3 % of the samples, respectively. In 44.8 % of the wines, the 6 ochratoxins appeared simultaneously. There was no evidence for ochratoxin A levels being greater in wines from Southern Europe than those described from North Europe. Samples from North Africa presented statistically the highest values for OTA, OTB, OTC and EtOTB

A π-Extended Donor-Acceptor-Donor Triphenylene Twin linked via a Pyrazine-bridge

Beta-amino triphenylenes can be accessed via palladium catalyzed amination of the corresponding triflate using benzophe-none imine. Transformation of amine 6 to benzoyl amide 18 is also straightforward and its wide mesophase range demon-strates that the new linkage supports columnar liquid crystal formation. Amine 6 also undergoes clean aerobic oxidation to give a new twinned structure linked through an electron-poor pyrazine ring. The new discotic liquid crystal motif contains donor and acceptor fragments, and is more oval in shape rather than disk-like. It forms a wide range columnar mesophase. Absorption spectra are strong and broad; emission is also broad and occurs with a Stokes shift of ca. 0.7 eV, indicative of charge-transfer characte

Steam reforming of phenol as biomass tar model compound over Ni/Al₂O₃ catalyst

Catalytic steam reforming of phenol over Ni/Al₂O₃ catalyst with 10 wt% of Ni loading was carried out in a fixed bed reactor. The effect of temperature (650–800 °C), reaction time (20–80 min) and catalyst amount (0–2 g corresponding to 0–4.5 gcat h gphenol−1) on carbon conversion, H2 potential and catalyst deactivation was studied. High efficiency of Ni/Al₂O₃ catalyst in steam reforming of phenol is observed at 750 °C for a reaction time of 60 min when 1.5 g of catalyst (3.4 gcat h gphenol−1) is used, with carbon conversion and H2 potential being 81 and 59%, respectively. An increase in temperature enhances phenol reforming reaction as well as coke gasification, minimizing its deposition over the catalyst. However, at high temperatures (800 °C) an increase in Ni crystal size is observed indicating catalyst irreversible deactivation by sintering. As catalyst time on stream is increased the coke amount deposited over the catalyst increases, but no differences in Ni crystal size are observed. An increase in catalyst amount from 0 to 1.5 g increases H2 potential, but no further improvement is observed above 1.5 g. It is not observed significant catalyst deactivation by coke deposition, with the coke amount deposited over the catalyst being lower than 5% in all the runs

Steam reforming of different biomass tar model compounds over Ni/Al2O3 catalysts

This work focuses on the removal of the tar derived from biomass gasification by catalytic steam reforming on Ni/Al2O3 catalysts. Different tar model compounds (phenol, toluene, methyl naphthalene, indene, anisole and furfural) were individually steam reformed (after dissolving each one in methanol), as well as a mixture of all of them, at 700 °C under a steam/carbon (S/C) ratio of 3 and 60 min on stream. The highest conversions and H2 potential were attained for anisole and furfural, while methyl naphthalene presented the lowest reactivity. Nevertheless, the higher reactivity of oxygenates compared to aromatic hydrocarbons promoted carbon deposition on the catalyst (in the 1.5–2.8 wt.% range). When the concentration of methanol is decreased in the feedstock and that of toluene or anisole is increased, the selectivity to CO is favoured in the gaseous products, thus increasing coke deposition on the catalyst and decreasing catalyst activity for the steam reforming reaction. Moreover, an increase in Ni loading in the catalyst from 5 to 20% enhances carbon conversion and H2 formation in the steam reforming of a mixture of all the model compounds studied, but these values decrease for a Ni content of 40%. Coke formation also increased by increasing Ni loading, attaining its maximum value for 40% Ni (6.5 wt.%)

Design of cost-efficient and photocatalytically active Zn-based MOFs decorated with Cu2O nanoparticles for CO2 methanation

Here we show for the first time a MOF that is photocatalytically active for light-assisted CO2 methanation under mild conditions (215 °C) without the inclusion of metallic nanoparticles or any sacrificial agent. The presence of Cu2O nanoparticles causes a 50% increase in the photocatalytic activity. This result paves the way for developing efficient and cost-effective materials for CO2 elimination