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In this work, a castor-oil-based process for flexible polyurethane foam scrap decomposition was used to prepare a recycled-based polyurethane foam. Decomposed polyurethane (DP) and 4,4′ diphenylmethane diisocyanate (MDI) were polymerized at three distinct MDI/DP ratios (1.0/2.2, 1.0/2.7 and 1.0/3.2) and two curing times (15 and 50 min). The influence of castor oil on the decomposition process and subsequent synthesis of polyurethane foam were evaluated using Fourier transform infrared spectroscopy (FTIR). Further characterization of the final material was carried out through thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and mechanical testing. FTIR assessment showed the presence of multi-functional hydroxyl groups as a result of the decomposition process. TGA confirmed three thermal degradation zones between 160 ℃ and 535 ℃ indicating the degradation of non-reacted compounds as well as the presence of oligomers, fatty acid chains, and urethane network. Mechanical evaluation evidenced that the MDI/DP ratios had a significant effect on tensile properties. The addition of DP increased the elongation at break and reduced the tensile strength with a slight variation of curing time. From the perspective of pore size, SEM micrographs exhibited that cell size apparently decreased with the addition of the DP.

The inhabitants of the town of Salache, Cotopaxi-Ecuador consume water from underground sources. In order to know the quality of the water, laboratory tests were carried out, determining that the water contains 450 mg L-1 of sulfates, as well as 520 and 583 mg CaCO3 L-1 of alkalinity and hardness, respectively. The Ecuadorian standard indicates that sulfates must be at 200 mg L-1, and that alkalinity as well as hardness must not exceed 500 mg CaCO3 L-1. Through experimental tests of downward filtration, the individual effectiveness of the filter materials sand, zeolite and strong acid cationic resin, in removing the concentrations of sulfates and calcium carbonate, was verified. The sand filtration results allowed the removal of alkalinity concentrations to 340 mg of CaCO3 L-1, hardness to 225 mg of CaCO3 L-1 and sulfates to 315 mg L-1. The zeolite bed reduced alkalinity to 280 mg of CaCO3 L-1, hardness to 257 mg of CaCO3 L-1 and sulfates to 320 mg L-1. The strong acid cationic resin was more effective in reducing alkalinity to 198 mg of CaCO3 L-1, hardness to 180 mg of CaCO3 L-1 and sulfates to 120 mg L-1. Los habitantes del poblado de Salache, Cotopaxi-Ecuador, consumen agua de fuentes subterráneas. Con la finalidad de conocer la calidad del agua se realizó pruebas de laboratorio determinándose que el agua contiene 450 mg L-1 de sulfatos, así como 520 y 583 mg CaCO3 L-1 de alcalinidad y dureza respectivamente. La norma ecuatoriana indica que los sulfatos deben encontrarse en 200 mg L-1, y que la alcalinidad al igual que la dureza no deben sobrepasar los 500 mg CaCO3 L-1. Mediante pruebas experimentales de filtración descendente se comprobó la efectividad individual de los materiales filtrantes arena, zeolita y resina catiónica de ácido fuerte, en la remoción de las concentraciones de sulfatos y carbonato de calcio. La filtración en lecho de arena redujo las concentraciones de alcalinidad a 340 mg CaCO3 L-1, dureza a 225 mg CaCO3 L-1 y sulfatos a 315 mg L-1. El lecho de zeolita, redujo la alcalinidad a 280 mg CaCO3 L-1, dureza a 257 mg CaCO3 L-1 y sulfatos a 320 mg L-1. La resina catiónica de ácido fuerte tuvo mayor efectividad reduciendo la alcalinidad a 198 mg CaCO3 L-1, la dureza a 180 mg CaCO3 L-1 y sulfatos a 120 mg L-1.

A general dynamic model of monolith catalytic reactors is developed to elucidate the intricacy of the physicochemical phenomena that occur in it. The dynamic model includes microkinetic reactions on a washcoat catalyst, which is incorporated in a heat- and mass-transfer submodels based on the quasi-2D analysis of both gas- and solid-phases. To support the derived general dynamic model, a dimethyl ether (DME) catalytic reactor that uses Pt/ZSM-5 catalyst is developed and simulated. The model prediction is validated using experimental data under nearly stoichiometric, lean, and rich conditions. The results demonstrate the catalytic conversion and selectivity of DME, distribution of the wall temperature, distribution of the species concentrations in steady-state, and transient response of the catalytic reaction. We found that the time response of the lowest inlet-gas temperature can be yielded ∼6 min, but the DME conversion is limited under the low-temperature condition.

Prediction of the PEFC’s behavior represents an important stage of the material and efficiency improvement. In the present work, the influence of the operating temperature for a PEFC with Nafion® 112 membrane was investigated to predict its behavior, and empirical correlations based on experimental data were established. Voltage-current curves, power-current curves, and voltage-anode flow curves were obtained under 55 psig constant pressure at four different temperatures (65 - 80℃), and current from 0 to 24.5 A with a step of 0.25 A. A Fuel Cell Test System 850e, hydrogen, oxygen and nitrogen tanks, and a PEFC single cell were employed to conduct experimental work. By using fitting tools, correlations are proposed with coefficient of determination bigger than 0.99.

La investigación tuvo como objetivo evaluar dos métodos de sensibilidad para la inhibición del crecimiento de Staphylococcus aureus subsp. aureus (ATCC® 11632), el método de Kirby-Bauer y el de pozos modificados de agar, mediante la utilización de miel de abeja pura de Apis mellifera en una concentración al 100%. El método modificado en pozos de agar formó halos de inhibición de 25.04 mm y el de Kirby-Bauer de 21.15 mm, indicando que el método modificado en pozos de agar es más sensible que el de Kirby-Bauer., The aim of this research was to evaluate two methods of sensitivity for the inhibition of the growth of Staphylococcus aureus subsp. aureus (ATCC® 11632), the Kirby-Bauer method and the modified agar wells, using honey 100% from Apis mellifera. The modified method in agar wells formed inhibition halos of 25.04 mm and that of Kirby-Bauer of 21.15 mm, indicating that the modified method in agar wells is more sensitive than the Kirby-Bauer method.The aim of this research was to evaluate two methods of sensitivity for the inhibition of the growth of Staphylococcus aureus subsp. aureus (ATCC® 11632), the Kirby-Bauer method and the modified agar wells, using honey 100% from Apis mellifera. The modified method in agar wells formed inhibition halos of 25.04 mm and that of Kirby-Bauer of 21.15 mm, indicating that the modified method in agar wells is more sensitive than the Kirby-Bauer method.

The synthetic auxin 2,4¿dichlorophenoxyacetic acid (2,4¿D) functions as an agro-nomic weed control herbicide. High concentrations of 2,4¿D induce plant growthdefects, particularly leaf epinasty and stem curvature. Although the 2,4¿D triggeredreactive oxygen species (ROS) production, little is known about its signalling. In thisstudy, by using a null mutant in peroxisomal acyl CoA oxidase 1 (acx1¿2), we iden-tified acyl¿coenzyme A oxidase 1 (ACX1) as one of the main sources of ROS pro-duction and, in part, also causing the epinastic phenotype following 2,4¿Dapplication. Transcriptomic analyses of wild type (WT) plants after treatment with2,4¿D revealed a ROS¿related peroxisomal footprint in early plant responses, whileother organelles, such as mitochondria and chloroplasts, are involved in later re-sponses. Interestingly, a group of 2,4¿D¿responsive ACX1¿dependent transcriptspreviously associated with epinasty is related to auxin biosynthesis, metabolism, andsignalling. We found that the auxin receptor auxin signalling F¿box 3 (AFB3), acomponent of Skp, Cullin, F¿box containing complex (SCF) (ASK¿cullin¿F¿box) E3ubiquitin ligase complexes, which mediates auxin/indole acetic acid (AUX/IAA)degradation by the 26S proteasome, acts downstream of ACX1 and is involved in theepinastic phenotype induced by 2,4¿D. We also found that protein degradationassociated with ubiquitin E3¿RING and E3¿SCF¿FBOX in ACX1¿dependent signallingin plant responses to 2,4¿D is significantly regulated over longer treatment periods, This study was funded by the Spanish Ministry of Science, Innovation and Universities (MCIU), the State Research Agency (AEI) and FEDER grant PGC2018-098372-B-I00. MAP-V was supported by MCIU Research Personnel Training (FPI) grant BES-2016-076518.

Process intensification (PI) is a major area of interest for downstream processing in biorefineries, where dilute aqueous streams must be processed to separate and purify valuable components. For example, lactic acid (LA) purification faces these challenges as the feed consists of a dilute aqueous mixture of LA and other organic acids as impurities. These characteristics result in high energy requirements, large equipment, and multiple operations when considering conventional technologies. The combination of otherwise individual processing tasks is enabled by exploiting synergies following PI principles, which improves energy efficiency and reduces the processing equipment’s size. This study presents a new conceptual design of an intensified dual reactive dividing wall column (R-DWC), applied to lactic acid purification. This CAPE study is the first to investigate the effect of impurities that disrupt the reaction and the separation. The approach taken in this study is a mixed methodology based on a decomposition approach, shortcut calculations, and rigorous process simulation in Aspen Plus. The intensification and the heat integration of this new realistic process led to a more eco-efficient operation in terms of material intensity (over 50 % reduction), water consumption (35 % reduction) and energy intensity (25 % reduction) compared to a 4-column flowsheet that does not account for reactive impurities and additional azeotropes. The recovery (> 95 %) and purity (88 % w/w LA) targets were successfully achieved, and the acid impurity was effectively removed.

Plant based biochars are proposed as soil amendments to immobilize potentially toxic trace elements (PTEs), such as Cd(II), Pb(II) and Zn(II) and aid in soil restoration. However, the sorption capacity of biochar for these elements can vary widely depending on biochar nature and metal properties. Currently, there is no clear methodology to pre-screen biochars for their suitability as adsorbents for these elements. Therefore, to facilitate biochar selection for application in soil restoration, this study explored the relationships between the physico-chemical properties of five plant-based biochars and their capacity to immobilize Cd(II), Pb(II) and Zn(II). Batch experiments using synthetic soil pore water were used to assess the sorption of these elements. The sorption isotherms described by the Hill model indicated that PTE sorption capacity followed the order Pb(II) > Cd(II) >Zn(II) regardless of biochar type in mono-element systems. Preferential sorption of Pb(II) limited the immobilization of Cd(II) and Zn(II) in multi-element systems. ATR-FTIR and SEM-EDX spectroscopy studies indicated that Cd(II) and Pb(II) sorption was mediated by complexation with carboxylic groups, cation–π interactions and precipitation with phosphates and silicates, while Zn(II) sorption occurred mainly by complexation with phenolic groups and precipitation with phosphates. A high correlation (>0.8) between Electrical Conductivity, Cation Exchange Capacity, pH and sorption capacity was identified for all metals tested, highlighting the electrostatic nature of the sorption mechanisms involved. Biochars derived from herbaceous feedstock were better candidates for remediation of soil polluted with Cd(II), Pb(II) and Zn(II), rather than wood-derived biochar. Overall, this study provides evidence of the direct relationship between specific properties of plant-based biochars (pH and EC) and their suitability as adsorbents for some PTEs in soil systems., Environmental chemistry; Environmental management; Environmental pollution; Soil chemistry; Soil pollution; Soil pore water, Cooperative sorption, S-shape isotherm, Hill-isotherm, Correlation analysis, Trace elements.

A microwave hydrothermal treatment was used for the chemical production of lactic acid from alginate extracted from the brown seaweed Padina Durvillaei, collected in the coastal area of Ecuador. The microwave hydrothermal treatment was studied through a response surface methodology based on the Box-Behnken design, using temperature, reaction time, and catalyst concentration as the manipulated variables and the yield as a response factor. The characterization of alginate was performed by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The lactic acid produced was quantified using Gas Chromatography - Ion Mobility Spectrometry (GC-IMS). The results show that temperature and catalyst concentration played the most critical roles in alginate extraction and lactic acid production. The optimal experimental conditions for alginate extraction from brown seaweed were: temperature = 92.91°C, time = 110.81 min and catalyst (Na2CO3) concentration = 2.60%, with a yield = 29.19%. Although the experimental evidence indicates a positive influence of microwaves' use on the production of lactic acid from alginate through hydrothermal treatment, a new study considering temperatures above 220°C and reaction times below 60 min should be developed.

El presente estudio fue de tipo observacional comparativo; para lo cual se analizaron 40 cepillos dentales de la marca OralDent, los que fueron usados durante un mes por los integrantes de la Cooperativa de taxis “Simón Bolívar” de la ciudad de Riobamba, Ecuador; con el propósito de comparar la eficacia del ácido acético al 5% y la clorhexidina al 0,12% como desinfectantes. El análisis microbiológico arrojó la presencia de microorganismos en los cepillos dentales usados por los individuos que voluntariamente los cedieron para el estudio, tales como: C. albicans en mayor proporción, seguida de S. viridans, S. epidermidis y S. mutans, A. tubingensis, K. pneumoniae, E. coli, E. faecalis, P. vulgaris. En las muestras con concentraciones de microorganismos de 100.000 UFC/mL, una vez generado el proceso de desinfección con clorhexidina al 0,12% existió una disminución a valores menores de 20.000 UFC/mL o su eliminación completa. El ácido acético al 5% logró una asepsia en el 100% de los cepillos dentales sin importar la edad o el género del individuo que lo utilizó.

In this paper, we describe the experimentation with a convolutional neural network for segmenting retinal net from pathological fundus images of preterm born children. Segmenting retinal net from pathological fundus images is a fundamental task to aid computer diagnosis. We used U-net architecture for training and testing. Testing with ROPFI dataset, we obtained an area under the receiver operating curve equal to 0.9180; when average sensitivity is equal to 0.700, the average specificity is equal to 0.9710. This performance is higher than prior works using a similar dataset.

This study developed a thermodynamic model of a set of sulfuric acid decomposers for thermochemical hydrogen production. It was integrated with a 1 MW tubular-type solid oxide fuel cell (SOFC) stack. With the model, we evaluated the feasibility of the combined production of electric power, heat, and sulfur dioxide for thermochemical H2 production. The integrated reactor model consists of three parts: i) SOFC submodel, ii) sulfuric acid decomposition (SAD) submodel, and iii) sulfur trioxide decomposition (STD) submodel with the catalysts Pt/γAl2O3 and WX-1. The efficiency of the integrated system was evaluated at a low-pressure range by polarization and efficiency curves for the SOFC, as well as pinch analysis for the SAD. The highest SOFC efficiency and SO2 production were achieved at 1.25 bar, whereas the lowest fuel consumption and heat demand for SO2 production were achieved at 3.0 bar. Furthermore, WX-1 performed better in the high-temperature range, whereas Pt/γAl2O3 performed better than WX-1 under low-temperature conditions. The Pt-supported catalyst could achieve SO3 conversion of 66% and SO2 yield of 57% at a gas temperature of 1025 K using the proposed integrated reactor design.

espanolEste articulo analiza el efecto del 1-Meticlciclpropeno en la inhibicion de etileno en el fruto de babaco (Vasconcellea x heilbornii var. Pentagona) en tres estados de madurez del fruto y tres tiempos de exposicion. Se empleo un Diseno Completamente al Azar (DCA) con cuatro repeticiones. Las variables bajo estudio fueron: la perdida de peso, la frmeza, la concentracion total de solidos solubles y el porcentaje de acidez titulable. La menor perdida de peso se registro para frutos cosechados de forma temprana (color “Verde”) y expuestos al 1-Meticlciclpropeno por un periodo corto (7 dias). En el caso de la variable frmeza de fruto, los mejores resultados se obtuvieron al cosechar los frutos cuando estos se cosechan en estado “Verde”. La concentracion de solidos solubles fue mayor para los frutos cosechados en estado “Verde-Amarillo” y “Amarillo”, mientras que los valores de porcentaje de acidez titulable se incrementan con la madurez del fruto. El tiempo de inmersion no tuvo efectos signifcativos para las variables frmeza de fruto, concentracion de solidos solubles y porcentaje acidez titulable. EnglishThis article analyzes the effect of 1-Meticlclclpropen on the inhibition of ethylene in babaco fruit (Vasconcellea x heilbornii var. Pentagona), with three ripe stages and three exposition times. A Complete Random Design with four repetitions was used. The variables under study were: loss of weight, fruit firmness, total concentration of soluble solids and percentage of titrated acidity. The lowest loss of weight was obtained for fruits harvested earlier (“Green”) and exposed to 1-Meticlciclpropen for a short period of time (7 days). In the case of fruit firmness, the best results were obtained when fruits were harvested “Green”. The total concentration of soluble solids was higher for fruits harvested in stages “Green-Yellow” and “Yellow”, while the values of titrated acidity increased with the fruit ripeness. The time of exposure to 1-Meticlclclpropen had no significant effect on fruit firmness, total concentration of soluble solids and percentage of titrated acidity.

Introduction.Ecuador occupies the fourth place in cocoa exports with 293,487 tons per year, produced on 559,617 hectares. However, its yield per hectare is low mainly due to the presence of pathogens that affect the pods.Objective.To evaluates different methods of control of pathogens of theTheobroma cacaocv ‘CCN-51’ pod.Materials and methods.The work was carried out in Luz de America, Santo Domingo de los Tsachilas, Ecuador, between 2016 and 2017. The treatments were the result of the combination of cultural practices + two fungicides (Chlorothalonil and Pyraclostrobin) + one biofungicide Serenade® (Bacillus subtilisQST713), with and without fertilizers. In total, 16 treatments were evaluated with 3 replicates or blocks, installed in a commercial cocoa plantation cv ‘CCN-51’ and under a Randomized Complete Block Design (RCBD).Results.The use of fungicides (chemical and biological), decreased the incidence of moniliasis (Moniliophthora roreri), black pod rot (Phytophthoraspp.), and cherelle wilt; but the application of fertilizers did not increase the effectiveness of these products. Treatment with only cultural practices did not decrease the final incidence of moniliasis, nor of brown rot, in contrast, the final incidence of cherelle wilt increased. The number of pods and the yield were not directly related and the highest yield of fermented and dry cocoa, corresponded to T9 [Cultural labors + Serenade® (0.2 kg ha-1) (every 15 days) + Fertilizer (0.3 kg ha-1) + Fertilizer (1 kg plant-1)], a treatment that also had the highest net income per hectare.Conclusion.Chemical and biological control can manage cocoa pods pathogens. The integration of both control methods allowed the cocoa producer to obtain greater income. Introducción.Ecuador ocupa el cuarto lugar en exportaciones de cacao con 293 487 toneladas al año, producidas en 559,617 hectáreas. Sin embargo, su rendimiento por hectárea es bajo debido principalmente a la presencia de patógenos que afectan la mazorca.Objetivo.Evaluar métodos de control de patógenos de la mazorca deTheobroma cacaocv ‘CCN-51’.Materiales y métodos.El estudio se llevó a cabo en Luz de América, Santo Domingo de los Tsáchilas, Ecuador, entre 2016 y 2017. Los tratamientos fueron el resultado de la combinación de labores culturales + dos fungicidas (Clorotalonil y Pyraclostrobin) + un biofungicida Serenade® (Bacillus subtilisQST713), con y sin fertilizantes. En total se evaluaron dieciséis tratamientos con tres réplicas o bloques, instalados en una plantación comercial de cacao cv ‘CCN-51’ y bajo un diseño de bloques completos al azar (DBCA).Resultados.El uso de fungicidas (químicos y biológicos), disminuyó la incidencia de la moniliasis (Moniliophthora roreri), pudrición negra de la mazorca (Phytophthoraspp.) y cherelle wilt; pero la aplicación de fertilizantes no aumentó la efectividad de estos productos. El tratamiento solo con labores culturales, no disminuyó la incidencia final de la moniliasis, tampoco de la pudrición negra de la mazorca, en cambio, aumentó la incidencia final del cherelle wilt. El número de mazorcas y el rendimiento no estuvieron directamente relacionados y el mayor rendimiento de cacao fermentado y seco, correspondió al T9 [labores culturales + Serenade® (0,2 kg ha-1) (c/ 15 días) + fertilizante, (0,3 kg ha-1) + abono (1 kg planta-1)], tratamiento que también tuvo el mayor ingreso neto por hectárea.Conclusión.El control químico y biológico pueden combatir patógenos de la mazorca de cacao. La integración de los dos métodos de control permitió al productor obtener mayores ingresos.

Introduction: Alcohol-associated liver disease (ALD) is the leading cause of liver-related mortality in Latin-America, yet the impact of public health policies (PHP) on alcohol consumption and liver disease is unknown. Objectives: To assess the association between alcohol PHP, alcohol consumption, and cirrhosis in Latin-American countries. Methods: We performed an ecological multi-national study including 20 countries in Latin-America (628,466,088 inhabitants). We obtained country-level socio-demographic information from the World Bank Open Data source. Alcohol-related PHP data for countries in Latin-America were obtained from the World Health Organization (WHO) Global Information System of Alcohol and Health (GISAH). We used a fixed-effects model to estimate proportions and multiple linear regression models to examine the association between the number of PHP and outcomes (alcohol intake, and deaths due to cirrhosis & traffic injuries). Results: The prevalence of obesity was 27% and 26.1% among males and females, respectively. The estimated alcohol per capita consumption (APC) among the population 15 years old was 6.8 liters of pure alcohol (5.6 recorded and 1.2 unrecorded). The countries with the highest APC were Uruguay (10.8 liters), Argentina (9.8 liters), and Chile (9.3 liters). The overall prevalence of alcohol use disorders (AUD) was 4.9%. ALD was the main cause of cirrhosis in 64.7% of males and 40.0% of females. A total of 19 (95%) countries have at least one alcohol-related PHP on alcohol. The most frequent PHP were: limiting drinking age (95%), tax control (90%), alcohol and driving (90%), and government monitoring systems (90%)(Table). A higher number of alcohol-related PHP was associated with a lower odds of AUD (OR 0.83, 95%CI:0.73-0.94; p=0.004), lower mortality due to ALD (OR 0.18, 95%CI:0.07-0.46, p

En el presente estudio se analizaron los parámetros del funcionamiento real de un motor de combustión interna ciclo Otto, que utiliza como combustible hidrógeno más gasolina; se determinaron dos ecuaciones estequiométricas. En la primera ecuación, los reactivos son el octano y el aire, en la segunda ecuación se adicionó la cantidad real de 3.86 moles de H2 obtenidas de una celda de hidrógeno. A partir de las ecuaciones químicas se determinaron dos sistemas de ecuaciones para obtener el consumo y la potencia, manteniendo las condiciones a la altura de Quito de 2850 msnm, 72.794 kPa de presión atmosférica y 300 K de temperatura ambiente. Se utilizó un motor mono cilindro alimentado con hidrógeno más gasolina, y se obtuvieron datos reales de potencia del motor con las mezclas aire-gasolina e hidrógeno-gasolina. La potencia teórica sin H2 fue 3.91 HP y con H2 de 5.41 HP, con un aumento del 27.1%; la potencia real es 3.78 HP sin H2 y 4.66 HP con H2, la cual se incrementó en un 16.7%. El consumo de combustible teórico es 401.61 g/kWh y con adición de H2 es menor a 373.52 g/kWh; el consumo real que indica el fabricante es 395 g/kWh.

Gluten-free breads were developed by incorporating unripe banana flour in a blend of alternative flour/cassava starch, 45/50. A factorial design was applied to determine the simultaneous effect of percentage of unripe banana flour (2, 8, 15%) and the type of alternative flour (quinoa, oyster mushroom, yellow pea and lentil flour) on structural and colour properties of bread. Principal component analysis was used to evaluate the behaviour of the formulations from a comprehensive perspective. Three formulations, denoted as P8 (pea + 8% unripe banana flour), Q15 (quinoa + 15% unripe banana flour) and L15 (lentil + 15% unripe banana flour) exhibited the closest profiles to reference (wheat bread). Breads with oyster mushroom flour showed a profile significantly different from the rest of formulations. The interactions among the factors were significant for all studied properties and showed that the unripe banana flour fortification did not lead to proportional responses on the bread properties, but the behaviour of unripe banana flour in breadmaking relied on the percentage and the type of alternative flour used. The P8, Q15 and L15 exhibited high fibre content and carbohydrate content lower than the reference. In addition, P8 formulation can be classified as intermediate glycaemic index.

Se han descrito muchos estudios de biosíntesis de nanopartículas de plata usando el extracto del bulbo de ajo (Allium sativum) como agente reductor. Sin embargo, el uso de sus hojas es poco conocido, por considerarse un producto de desecho. En este estudio, se comparó el tamaño de nanopartículas de plata obtenidas con el extracto acuoso de las hojas de ajo usando dos técnicas diferentes de calentamiento: placa y por microondas. Las nanopartículas obtenidas se caracterizaron por espectrofotometría UV-Visible, microscopía de transmisión electrónica (TEM, por sus siglas en inglés), dispersión dinámica de luz (DLS, por sus siglas en inglés) y difracción de rayos X (XRD, por sus siglas en inglés). Como resultado se obtuvieron nanopartículas con un tamaño promedio de 15,4±7,9 y 9,9±10,5 nm empleando las dos técnicas respectivamente. De acuerdo al análisis estadístico realizado, se demostró que existen diferencias significativas en relación al tamaño de nanopartícula obtenido. Se concluye que el extracto acuoso de las hojas de la planta de ajo, es un agente reductor adecuado para la síntesis de nanopartículas de plata, y que la técnica de microondas es más efectiva por la rapidez y tamaño de nanopartículas obtenidas.

HbA1c level reflects chronic glycemic status if reliable tests are used. The HbA1c testing improved with the efforts of many national and international organizations; however, in some regions, high performing assays might not be readily available. Here we report a comparison study of two immunoassay methods with a high-performance liquid chromatography (HPLC) assay, all of them available in Ecuador. We studied 114 fresh whole-blood samples from adults with normal and pathological HbA1c levels. HbA1c was measured in all samples by DCA-Vantage point-of-care analyzer, I-Chroma portable fluorescent scanner immunoassay and BioRad Variant II Turbo HPLC. Blood samples with variants of hemoglobin were excluded. HbA1c values were expressed in National Glycohemoglobin Standardization Program percentages and mmol/mol, as mean ± standard deviation. Results: HbA1c measurements by HPLC and DCA-Vantage were similar: 6.3±1.7% (45±18.6 mmol/mol) vs. 6.3±1.8% (45±19.7 mmol/mol), respectively, P=0.057, while HbA1c values by I-Chroma were lower than HPLC, 5.8±1.9% (40±20.8 mmol/mol), P Disclosure B.J. Pazmiño Gomez: None. F.E. Vera Lorenti: None. M.E. Guadalupe Vargas: None. G.M. Alvarez Condo: None. D. Veron: None. A.G. Cercado: None. E.I. Rodas Neira: None. B. Bahar: None. D. Veron: None. Funding Ministry of Higher Education, Science, Technology and Innovation, Ecuador/Prometeo Project/State University of Milagro, Ecuador (UNEMI-OCAS-SO-27092013-N?26 DV2013?2014, UNEMI-OCAS-SO-03072014-N8-DV2014-2015, UNEMI-OCAS-SO-30052016-N5-DV2015-2017)

The promotional effect of sodium on Pt/Al 2 O 3 catalysts for the water–gas shift (WGS) reaction was investigated with operando FTIR during steady-state and isotopic transient experiments. The highest turnover frequency (TOF) promotion per surface Pt occurred on a 0.82 wt.% Pt/Al 2 O 3 catalyst with a 30:1 molar ratio of Na:Pt. This catalyst exhibited a TOF of 0.35 s −1 at 250 °C and 7% CO, 11% H 2 O, 9% CO 2 , and 37% H 2 compared to 0.43 × 10 −2 s −1 on Pt/Al 2 O 3 . Operando IR revealed that Na addition modifies CO adsorption on Pt to create more strongly bound, multiply-bonded CO species at 1768 cm −1 and 1697 cm −1 compared to predominantly linear CO on Na-free Pt/Al 2 O 3 at 2060 cm −1 . Transient experiments with 12 CO/ 13 CO isotope switches showed that the number of carbon-containing active intermediates increased from less than 1% of the surface Pt for Na-free Pt/Al 2 O 3 to nearly 100% of the surface Pt for 20Na:Pt/Al 2 O 3 , which indicates that only a small fraction of the Pt surface on the Na-free samples participates in the WGS reaction. From time-resolved IR spectra during transient WGS with 12 CO/ 13 CO and 12 CO 2 / 13 CO 2 isotope switches, we propose that surface formate species are spectators for all Na-promoted Pt/Al 2 O 3 catalysts under these WGS conditions. The results suggest that Na promotes Pt/Al 2 O 3 for WGS by modifying the local electronic properties of Pt and creating new H 2 O activation sites, which provide greater availability of surface OH/H species to react with nearly all CO on the metallic Pt surface through a non-formate pathway.

The hydrodynamics of trickle bed reactors operating near the trickle-bubbly flow regime transition have not been fully characterized in the literature. In this work, an air–water system is used to investigate the effects of particle size, particle shape, void fraction, and surface tension on the trickle-bubbly flow regime transition in trickle bed reactors. The flow regime transition is detected based on standard deviation of pressure drop with confirmation by visual observation. For all cases, the liquid superficial velocity required for the trickle-bubbly transition was found to be relatively independent of the gas superficial velocity ( v G = 4–40 mm/s). Literature models, defined for the trickle-pulse transition, are unable to predict this trend when extrapolated to low gas superficial velocities ( v G ⩽ 40 mm/s). To address this gap, a correlation is proposed based on the experimental data gathered in this work.

Lab on a Chip (LOC) farming systems have emerged as a powerful tool for single cell studies combined with a non‐adherent cell culture substrate and single cell capture chips for the study of single cell derived tumor spheres. Cancer is characterized by its cellular heterogeneity where only a small population of cancer stem cells (CSCs) are responsible for tumor metastases and recurrences. Thus, the in vitro strategy to the formation of a single cell‐derived sphere is an attractive alternative to identify CSCs. In this study, we test the effectiveness of microdevices for analysis of heterogeneity within CSC populations and its interaction with different components of the extracellular matrix. CSC could be identify using specific markers related to its pluripotency and self‐renewal characteristics such as the transcription factor Oct‐4 or the surface protein CD44. The results confirm the usefulness of LOC as an effective method for quantification of CSC, through the formation of spheres under conditions of low adhesion or growing on components of the extracellular matrix. The device used is also a good alternative for evaluating the individual growth of each sphere and further identification of these CSC markers by immunofluorescence. In conclusion, LOC devices have not only the already known advantages, but they are also a promising tool since they use small amounts of reagents and are under specific culture parameters. LOC devices could be considered as a novel technology to be used as a complement or replacement of traditional studies on culture plates. Fil: Belgorosky, Denise. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Fernández Cabada, Tamara. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Peñaherrera Pazmiño, Ana Belén. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Langle, Yanina Verónica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Booth, Ross. Millipore Sigma Corporation; Estados Unidos Fil: Bhansali, Shekhar. University of Florida; Estados Unidos Fil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. University of Florida; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Eijan, Ana Maria. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lerner, Betiana. Universidad Tecnologica Nacional. Facultad Regional Haedo. Centro de Ingenieria de Recubrimientos Especiales y Nanoestructuras.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Type 2 diabetes mellitus (T2DM) and diabetic kidney disease (DKD) are prevalent diseases in South America. Identification of factors associated to DKD is key to design appropriate regional health policies. We characterized DKD in 1663 adults (99% Confidence level, 1.4% margin of error) recruited from the general population of the Ecuadorian coast between 2014 and 2017 (46±14 years of age, 64% of them were women). Framed in our prospective, observational and cross-sectional study (NCT02237352) we evaluated demographic data, personal and family history, BMI, blood pressure (BP), plasma glucose (PG), HbA1c, creatinine (cr) and microalbuminuria (μAlb). T2DM was defined as peoples with clinical diagnosis of T2DM, being on insulin or oral hypoglycemic treatment, fasting PG ≥126 mg/dl, random glucose ≥200 mg/dl and HbA1c ≥6.5%. Subjects were deemed to have DKD when they presented μAlb ≥30 mg/gr-cr and/or estimated glomerular filtration rate ˂60 ml/min/1.73m2. Results: Our study shows that the prevalence of DKD in the Ecuadorian coast was 9.3% (95% CI, 8%-11%) with 19.5% of the persons not knowing their T2DM status. The factors significantly different comparing DKD vs. non-DKD subjects (P Conclusion: Female gender, age, BMI, BP, PG, HbA1c, history of ONBC and GD all are factors linked to DKD in the Ecuadorian coast that should be considered to design meaningful health policies, to address the currently high prevalence of DKD. The amount of people unknowing their diagnosis of T2DM among folks with DKD suggests emphasizing the screening of T2DM. Disclosure M.E. Guadalupe: None. G.B. Alvarez Condo: None. F.E. Vera Lorenti: None. B.J. Pazmiño Gomez: None. E.I. Rodas Neira: None. D. Veron: None. A.G. Cercado: None. G.A. Villegas: None. A. Tufro: None. D. Veron: None.

El trabajo de investigación tuvo como objetivo evaluar la eficacia antimicrobiana in vitro del aceite esencial de tomillo (Thymus vulgaris) sobre Staphylococcus aureus. Se evaluaron concentraciones al 1, 5, 10, 30, 50, 70 y 90% en dilución en etanol al 96.8%. Se determinó la Concentración Mínima Inhibitoria mediante el método de microdilución en caldo. El inóculo bacteriano se estandarizó al 0.5 de la escala de MacFarland en espectofotómetro, teniendo como resultado que el tubo al 1% de aceite de tomillo no presentó turbidez. Este, al ser sembrado en agar Mueller-Hinton determinó la Concentración Bactericida Mínima donde no se observó crecimiento de colonias. Los resultados indican que los tratamientos al 5 y 10% no son significativamente diferentes (p, The objective of this study was to evaluate the in vitro antimicrobial efficacy of thyme essential oil (Thymus vulgaris) on Staphylococcus aureus. Concentrations at 1, 5, 10, 30, 50, 70 and 90% were evaluated in 96.8% dilution in ethanol. The Minimum Inhibitory Concentration was determined by the broth microdilution method. The bacterial inoculum was standardized to 0.5 of the MacFarland scale in spectrophotometer, with the result that the 1% tube of thyme oil did not present turbidity. This, when cultured on Mueller-Hinton agar, determined the Minimum Bactericidal Concentration where no colony growth was observed. The results indicate that treatments at 5 and 10% were not significantly different (p

The effect of degraded plastic with prodegradants on the polyethylene properties was studied. First, the mixture of low-density polyethylene (LDPE) with 5 wt.% prodegradant (oxo-degradable) additive was prepared by melt processing using a mixer chamber. Then, the degradation of the mixtures was evaluated by exposing the oxo-degradable LDPE in a Xenon arc chamber for 300 hours. The degraded material was characterized by infrared spectroscopy (FTIR) assessing the carbonyl index and the hydroperoxide band. Then, different percentages of degraded material (1, 5, 10, 20, and 50 wt.%) were incorporated into the neat LDPE. Mechanical and rheological tests were carried out to evaluate the recycling process of these blends. Also, the feasibility of the blends reprocessing was determined by analysing the melt flow index for each heating process and shear stress applied. It was evidenced that the increment of the content of the degraded material in the neat LDPE decreased the mechanical strength and the processability of blends due to the imminent thermal degradation. All the test results showed that the incorporation of degraded material causes a considerable reduction in the matrix properties during the reprocessing. Nevertheless, at low concentrations, the properties of the oxo-degradable LDPE–LDPE blends were found to be similar to the neat LDPE.

The study of glass formation is largely framed by semiempirical models that emphasize the importance of progressively growing cooperative motion accompanying the drop in fluid configurational entropy, emergent elasticity, or the vanishing of accessible free volume available for molecular motion in cooled liquids. We investigate the extent to which these descriptions are related through computations on a model coarse-grained polymer melt, with and without nanoparticle additives, and for supported polymer films with smooth or rough surfaces, allowing for substantial variation of the glass transition temperature and the fragility of glass formation. We find quantitative relations between emergent elasticity, the average local volume accessible for particle motion, and the growth of collective motion in cooled liquids. Surprisingly, we find that each of these models of glass formation can equally well describe the relaxation data for all of the systems that we simulate. In this way, we uncover some unity in our understanding of glass-forming materials from perspectives formerly considered as distinct.

Flavonoids are important value added products for dye sensitized solar cells biosensors, functional foods, medicinal supplements, nanomaterial synthesis, and other applications. Brassica oleracea contains high levels of anthocyanins in leaf sap vacuoles, and there are many viable extraction techniques that vary in terms of simplicity, environmental impact, cost, and extract photochemical/electrochemical properties. The efficiency of value added biotechnologies from flavonoid is a function of anthocyanin activity/concentration and molecule stability (i.e., ability to retain molecular resonance under a wide range of conditions). In this paper, we show that block cryoconcentration and partial thawing of anthocyanin from B. oleracea is a green, facile, and highly efficient technique that does not require any special equipment or protocols for producing enhanced value added products. Cryoconcentration increased anthocyanin activity and total phenol content approximately 10 times compared with common extraction techniques. Cryoconcentrated extract had enhanced electrochemical properties (higher oxidation potential), improved chroma, and higher UV absorbance than extract produced with other methods for a pH range of 2-12, with minimal effect on the diffusion coefficient of the extract. As a proof of concept for energy harvesting and sensor applications, dye sensitized solar cells and pH-sensitive thin films were prepared and tested. These devices were comparable with other recently published biotechnologies in terms of efficacy, but did not require expensive/environmentally detrimental extraction or concentration methods. This low cost, biorenewable, and simple method can be used for development of a variety of value added products. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:206-217, 2018.

(Received: 2014/08/01 - Accepted: 2014/09/22)The province of Bolivar is located in the central-west region of Ecuador. The main beverages produced are spirits and chichas; among them “rice chicha”. In a first stage, samples of rice chicha (at points of sale) from different producers of this province were evaluated; microbial counts and physicochemical analyzes were performed. In the second stage, the most representative enterobacteria, lactic acid bacteria, yeasts and molds were isolated form “rice chicha” during three phases of the elaboration process: initial, fermentative and final. For all microorganisms, macroscopic and microscopic descriptions were performed. The identification of enterobacteria and lactic acid bacteria was carried out with biochemical tests, for mold a microscopic identification was applied by staining with lactophenol blue solution and for yeast the APIC AUX 20 kit was used. Count values in average were 2.7 and 2.5 log CFU / ml of total coliforms and enterobacteria, 1.8 log CFU / ml of lactic acid bacteria and 2.5 log CFU / ml for yeasts and molds. During the three fermentation phases the most representative species were partially identified: 13 strains of Enterobacteriaceae, 9 strains of lactic acid bacteria, 15 strains of mold and 6 strains of yeast., (Recibido: 2014/08/01 - Aceptado: 2014/09/22)La provincia de Bolívar se encuentra ubicada en el centro-occidente del Ecuador. Las principales bebidas tradicionales que allí se producen son los aguardientes y las chichas; entre ellas sobresale la chicha de arroz. En una primera etapa, se evaluaron muestras de chicha de arroz (en los puntos de venta) de diferentes productores de la provincia; se realizaron recuentos microbiológicos y análisis físico-químicos. En la segunda etapa, se aislaron e identificaron enterobacterias, bacterias ácido lácticas, mohos y levaduras, en tres fases del proceso de elaboración (inicial, fermentativo y final). Para todos los microorganismos se realizaron descripciones macroscópicas y microscópicas. La identificación de enterobacterias y bacterias ácido lácticas se realizó mediante pruebas bioquímicas, para los mohos se realizó una identificación microscópica mediante tinción con azul de lactofenol y para las levaduras se usó el kit API 20 C AUX. En relación a los recuentos se obtuvieron en promedio valores de 2.7 y 2.5 log UFC/ml de coliformes totales y enterobacterias respetivamente, 1.8 log UFC/ml de bacterias ácido lácticas y 2.5 log UFC/ml de Mohos y levaduras. Se identificaron en las tres fases: 13 cepas de enterobacterias, 9 cepas de bacterias ácido lácticas, 15 cepas de mohos y 6 cepas de levaduras.

We apply a living polymerization theory to describe cooperative string-like particle rearrangement clusters observed in simulations of a coarse-grained polymer melt. The theory quantitatively describes the interrelation between the average string length L, configurational entropy Sconf, and the order parameter for string assembly Φ without free parameters. Combining this theory with the Adam-Gibbs (AG) model allows us to predict the relaxation time τ in a lower temperature T range than accessible by current simulations. In particular, the combined theories suggest a return to Arrhenius behavior near Tg and a low T residual entropy, thus avoiding a Kauzmann ‘entropy crisis’.

We perform coarse-grained simulations of model unentangled polymer materials to quantify the range over which interfaces alter the structure and dynamics in the vicinity of the interface. We study the interfacial zone around nanoparticles (NPs) in model polymer-NP composites with variable NP diameter, as well as the interfacial zone at the solid substrate and free surface of thin supported polymer films. These interfaces alter both the segmental packing and mobility in an interfacial zone. Variable NP size allows us to gain insight into the effect of boundary curvature, where the film is the limit of zero curvature. We find that the scale for perturbations of the density is relatively small and decreases on cooling for all cases. In other words, the interfaces become more sharply defined on cooling, as naively expected. In contrast, the interfacial mobility scale ξ for both NPs and supported films increases on cooling and is on the order of a few nanometers, regardless of the polymer-interfacial interaction strength. Additionally, the dynamical interfacial scale of the film substrate is consistent with a limiting value for polymer-NP composites as the NP size grows. These findings are based on a simple quantitative model to describe the distance dependence of relaxation that should be applicable to many interfacial polymer materials.

We perform molecular dynamics simulations on a coarse-grained polymer melt to study the dynamics of glass-formation in ring polymer melts of variable knot complexity. After generating melts of non-concatenated polymeric rings having a range of minimum crossing number values, mc, we compute the coherent intermediate scattering function, the segmental α-relaxation time, fragility, and the glass transition temperature as a function of mc. Variation of knot complexity is found to have a pronounced effect on the dynamics of polymer melts since both molecular rigidity and packing are altered, primary physical factors governing glass-formation in polymeric materials.

The effect of support on sulfur tolerance and regenerability under reducing environments was investigated by rate measurements for ethylene hydrogenation, hydrogen chemisorption, and extended X-ray absorption fine structure (EXAFS). Catalysts, 1 % Pt/Al2O3 and 1 % Pt/P25 (TiO2), were tested after sulfidation in H2S/H2 at 250 °C followed by regeneration treatments in H2 at 250, 350 and 450 °C. Our combined results showed a 20–27 times decrease in the rate of ethylene hydrogenation on both sulfided catalysts, accompanied by a 4–6 times drop in the Pt surface area. Regenerations up to 450 °C were unable to remove all the sulfur, as evidenced by the presence of Pt–S bonds by EXAFS at about 2.25–2.33 A, characteristic lengths for chemisorbed sulfur and bulk-type PtS. However, a partial recovery of the hydrogenation rate per mole of Pt was observed on sulfided Pt/Al2O3 after reduction at 450 °C, while the induction of strong metal support interactions (SMSI) at reduction temperature above 350 °C was observed on Pt/P25, regardless of the presence of sulfur. For Pt/P25, the reversal of the SMSI state together with sulfur removal by mild oxidation suggests that sequential reduction/oxidation treatments may be more effective in restoring the S-free state of TiO2-supported catalysts. Pt/Al2O3 and Pt/TiO2 (P25) sulfur tolerance and regenerability were evaluated after reduction treatments in H2. Both catalysts were equally poisoned by sulfur based on C2H4 hydrogenation. Reduction treatments up to 450 °C were not able to remove sulfur on either catalyst. Sulfur on Pt may inhibit the formation of the SMSI state on Pt/TiO2, especially below 350 °C.

Objective: The objective of this study was to determine the content of chromium (Cr), nickel (Ni), cadmium (Cd), boron (B), mercury (Hg), and lead (Pb) in chicken hen eggs in hen’s eggs and to evaluate their influence on the enzymatic activity of hen egg white lysozyme (HEWL).Methods: In this study, we have determined the content of Cr, Ni, Cd, B, Hg, and Pb in chicken hen eggs using absorption atomic (AA) method. The residual enzymatic activity of HEWL, HEWL was evaluated using spectrophotometric method.Results: The levels of Cr, Ni, Cd, B, Hg, and Pb in hen eggs were 1.8300, 1.1300, 0.5350, 0.5200, 0.0025, and 0.0021 mg/kg, respectively. The inhibition of enzymatic activity of HEWL, by exposure to heavy metals was studied. We found that Cr, Ni, Cd, B, Hg, and Pb produced a loss of enzymatic activity. Cr III was the metal with the highest reduction of HEWL enzymatic activity. 0.01 M of Cr III was able to reduce HEWL enzymatic activity levels up to 49% after 24 h of exposure to this metal. An exposure of 0.05 M of Cr III reduced HEWL enzymatic activity to 1%. 24 h exposure to 0.01 M of Cd presented a reduction of 37% of HEWL enzymatic activity and 0.05 M of Cd resulted in only 75% of HEWL enzymatic residual activity.Conclusions: Content of heavy metals in hen egg from Tungurahua region was high. Cr, Ni, Cd, B, Hg, and Pb produced a loss of enzymatic activity of HEWL.

Se ha reportado que las restauraciones adhesivas tras el aclaramiento dental, sufren una notable pérdida de resistencia a las fuerzas producidas por la masticación, razón por la cual la literatura recomienda esperar 15 días para realizar procedimientos adhesivos. Por este motivo el propósito de este estudio fue evaluar la eficacia del ascorbato de sodio como un agente que permita reducir el tiempo de espera de procedimientos adhesivos posteriores al aclaramiento. Se utilizaron 103 dientes bovinos, a los cuales se les seccionó la corona clínica y se colocó en cubos acrílicos. Los cuerpos de prueba se dividieron en 5 grupos los cuales fueron sometidos a aclaramiento con peróxido de hidrógeno al 40% en dos aplicaciones de 20 minutos cada una y un grupo control positivo donde no se realizó aclaramiento. Grupo No. 1: tratado con ascorbato de sodio al 10% por 10 minutos. Grupo No. 2: Ascorbato de sodio al 10% por 5 minutos. Grupo No. 3: Ascorbato de sodio al 5% por 10 minutos. Grupo No. 4: Ascorbato de sodio al 5% por 5 minutos. Y finalmente un grupo control negativo donde luego del aclaramiento no se colocó ascorbato de sodio e inmediatamente después del aclaramiento se hizo el proceso adhesivo. Los especímenes fueron sometidos a pruebas de cizallamiento. Los resultados fueron sujetos a análisis de ANOVA y reportaron que los grupos sometidos a aclaramiento presentaron una reducción en la fuerza de adhesión en relación al grupo control positivo, a pesar de la aplicación del ascorbato de sodio.

The promotional effect of alkali additives (Na, Li, and K) in the low-temperature (200–250 °C) water–gas shift reaction was studied for Pt/Al 2 O 3 and Pt/TiO 2 catalysts. Sodium showed the highest promotion of the turnover frequency (TOF), normalized by Pt on the surface. The TOF at 250 °C and 6.8% CO, 22% H 2 O, 37% H 2 , and 8.5% CO 2 was enhanced by Na up to 107 times (0.7 s −1 ) that of Pt/Al 2 O 3 (7 × 10 −3 s −1 ) and up to four times (0.7 s −1 ) the TOF of Pt/P25 TiO 2 (0.2 s −1 ). The addition of Na on Pt/Al 2 O 3 and Pt/TiO 2 changed the reaction orders, with H 2 O order increasing by ∼0.3, H 2 order increasing by 0.1–0.3, CO 2 order decreasing by 0.2, and CO order decreasing by 0.1–0.2. Together with an approximately 20 kJ mole −1 increase in E a , these data suggest Na creates the same type of active sites on both supports. X-ray absorption spectroscopy (XAS) experiments under WGS conditions indicate that the formation of Pt oxides is dependent on the catalyst preparation method, the type, and the loading of alkali. On catalysts where Pt oxides were observed, no correlation was found between the TOF and the fraction of PtO. The series of Pt/Na/Al 2 O 3 catalysts with the highest TOF showed fully reduced Pt under WGS conditions. Our results show that the promotion by alkali is caused by the modification of the properties of the support and that the active Pt remains in the metallic state. Thus, for metallic catalysts, alkali is added to the growing list of promoters that modify the support to improve water activation and the WGS reaction rate.

The stability of Pt catalysts for NO oxidation was analyzed by observing the effect of pre-adsorbed sulfur on the reaction kinetics using a series of Pt/SBA-15 catalysts with varying Pt particle sizes ( ca 2–9 nm). Our results indicate that sulfur addition did not influence catalyst deactivation of any of the Pt catalysts, resulting in unchanged turnover rates (TOR) and reaction kinetics. The presence of sulfur on Pt was confirmed by X-ray absorption fine structure spectroscopy (EXAFS) under reducing environments. However, exposure of the catalyst to NO oxidation conditions displaced sulfur from the first coordination shell of Pt, yielding Pt–O bonds instead. Re-reduction fully recovered the Pt–S backscattering, implying that sulfur remained near the Pt under oxidizing conditions. X-ray photoelectron spectroscopy (XPS) and chemisorption measurements confirmed the presence of sulfur near platinum. The invariance of the NO oxidation reaction to sulfur poisoning is explained by sulfur displacement to interfacial sites and/or sulfur binding on kinetically irrelevant sites. Formation of Pt oxides remains as the main source of catalyst deactivation as observed by kinetic and X-ray absorption spectroscopy (XAS) measurements.

In this work the differential response of adult and young leaves from pea (Pisum sativum L.) plants to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) (23 mm) applied by foliar spraying was investigated. The concentration of 2,4-D (23 mm) and the time of treatment (72 h) were previously optimized in order to visualize its toxic effects on pea plants. Under these conditions, the herbicide induced severe disturbances in mesophyll cells structure and proliferation of vascular tissue in young leaves and increased acyl-CoA oxidase (ACX), xanthine oxidase (XOD) and lipoxygenase (LOX) activities in young leaves, and only ACX and LOX in adult leaves. This situation produced reactive oxygen species (ROS) over-accumulation favoured by the absence of significant changes in the enzymatic antioxidants, giving rise to oxidative damages to proteins and membrane lipids. An increase of ethylene took place in both young and adult leaves and the induction of genes encoding the stress proteins, PRP4A and HSP 71,2, was observed mainly in young leaves. These results suggest that ROS overproduction is a key factor in the effect of high concentrations of 2,4-D, and ROS can trigger a differential response in young and adult leaves, either epinasty development in young leaves or senescence processes in adult tissues.

Objective: The aim of this study was to obtain pigeon pea protein concentrate (PC) of green seeds and mature seeds from Cajanus cajan grown in Ecuador and evaluate their functional properties.Methods: Pigeon PC of green seeds (GPPPC) and pigeon PC of mature seeds (MPPPC) were obtained by alkaline extraction (pH 8.5) using the isoelectric precipitation at pH 4.5 method. Content of protein was determined using the Dumas method. Functional properties were evaluated with the following functional properties: Protein solubility (PS), water absorption capacity (WAC), oil absorption capacity (OAC), emulsifying activity index (EAI), emulsion stability index (ESI), foaming capacity (FC), and foam stability (FS).Results: GPPPC and MPPPC are statistical different (p

The effect of Zn addition on the Pd turnover rate (TOR) for the water–gas shift (WGS) reaction was studied on 2 wt% Pd on alumina with Zn content varying from 0 to 19% Zn by weight. Over 85% of the Zn reacted with alumina to form zinc aluminate with a fraction reacting with Pd. The average Pd Zn coordination number as measured by extended X-ray absorption fine structure (EXAFS) increased monotonically from 0 to 4.5 as the Zn loading on alumina increased. At a loading of 2% Pd and 19% Zn on alumina the molar fraction of Zn in the Pd particles was 0.34, and the turnover rate increased by a factor of 13, as compared with the pure metallic Pd supported on alumina, to 3.6 × 10 −2 mol H 2 s −1 (mol exposed Pd)−1 at 280 °C, 6.8% CO, 8.5% CO2, 21.9% H2O, and 37.4% H2 at 1 atm. The formation of the ordered 1:1 PdZn intermetallic compound by deposition of Pd on zinc oxide increased the average Pd Zn coordination number to 5.9 and the WGS turnover rate by a factor of 20 to 5.3 × 10 −2 mol H 2 s −1 (mol exposed Pd)−1. The bonding of adsorbed CO changed from 80% bridging on pure Pd to 90% linear on the 1:1 PdZn intermetallic compound as determined by diffuse reflectance infrared spectroscopy performed under WGS conditions. The fraction of CO binding linearly to Pd correlated linearly with the WGS rate per Pd on the surface. Because the dispersion of the samples was about the same, this result implies that the number of active sites can be counted by the fraction of CO binding linearly. A simple random substitution model for PdZn distribution was used to estimate the concentration of Pd and Zn on the surface, based on the coordination numbers measured by EXAFS. The correlation of the reaction rate with the types of sites on catalysts with six different Pd Zn compositions shows that the data is consistent with an active site composed of surface Pd atoms with surface coordination to 2 Pd and 4 Zn atoms, which is the coordination expected for the (111) plane of the 1:1 PdZn intermetallic compound. An alternate explanation for the promotional effect of Zn on Pd/alumina is that the formation of zinc aluminate breaks a deleterious Pd–alumina interaction.

Phenylacetone monooxygenase (PAMO) from Thermobifida fusca is a FAD-containing Baeyer-Villiger monooxygenase (BVMO). To elucidate the mechanism of conversion of phenylacetone by PAMO, we have performed a detailed steady-state and pre-steady-state kinetic analysis. In the catalytic cycle ( k cat = 3.1 s (-1)), rapid binding of NADPH ( K d = 0.7 microM) is followed by a transfer of the 4( R)-hydride from NADPH to the FAD cofactor ( k red = 12 s (-1)). The reduced PAMO is rapidly oxygenated by molecular oxygen ( k ox = 870 mM (-1) s (-1)), yielding a C4a-peroxyflavin. The peroxyflavin enzyme intermediate reacts with phenylacetone to form benzylacetate ( k 1 = 73 s (-1)). This latter kinetic event leads to an enzyme intermediate which we could not unequivocally assign and may represent a Criegee intermediate or a C4a-hydroxyflavin form. The relatively slow decay (4.1 s (-1)) of this intermediate yields fully reoxidized PAMO and limits the turnover rate. NADP (+) release is relatively fast and represents the final step of the catalytic cycle. This study shows that kinetic behavior of PAMO is significantly different when compared with that of sequence-related monooxygenases, e.g., cyclohexanone monooxygenase and liver microsomal flavin-containing monooxygenase. Inspection of the crystal structure of PAMO has revealed that residue R337, which is conserved in other BVMOs, is positioned close to the flavin cofactor. The analyzed R337A and R337K mutant enzymes were still able to form and stabilize the C4a-peroxyflavin intermediate. The mutants were unable to convert either phenylacetone or benzyl methyl sulfide. This demonstrates that R337 is crucially involved in assisting PAMO-mediated Baeyer-Villiger and sulfoxidation reactions.

Grapes and raisins provide phenolic antioxidants, which contribute to their potential health benefits. The objectives of this study were to compare the antioxidant capacity and phenolic content of green Thompson seedless grapes (the most common variety of grapes consumed in the United States), sun-dried raisins, and golden raisins (both produced from Thompson seedless grapes) and to observe the effects of their consumption over 4 weeks in 15 healthy human males with a cross-over design. The oxygen radical absorbance capacity (ORAC) (positive statistical significance for grapes after 2 weeks and golden raisins after 3 weeks), serum oxidation (positive statistical significance for golden raisin lag time after 4 weeks), total phenolics (no significant effects), and C-reactive protein (no significant effects) were monitored. Immediately postconsumption, there were some significant nonpositive changes. It is hypothesized that these negative results may be explained by postprandial oxidation, a known effect after carbohydrate consumption. Golden raisins had the highest antioxidant capacity and phenolic content. The consumption of a serving of grapes or raisins each day, in addition to a typical diet, may not be sufficient to overcome postprandial oxidation when consumed with other high carbohydrate foods but may have beneficial antioxidant effects over time.