Graphene Oxide-Silver Nanoparticle Nanohybrids: Synthesis, Characterization, and Antimicrobial Properties.

Drug resistance of pathogenic microorganisms has become a global public health problem, which has prompted the development of new materials with antimicrobial properties. In this context, antimicrobial nanohybrids are an alternative due to their synergistic properties. In this study, we used an environmentally friendly one-step approach to synthesize graphene oxide (GO) decorated with silver nanoparticles (GO-AgNPs). By this process, spherical AgNPs of average size less than 4 nm homogeneously distributed on the surface of the partially reduced GO can be generated in the absence of any stabilizing agent, only with ascorbic acid (L-AA) as a reducing agent and AgNO3 as a metal precursor. The size of the AgNPs can be controlled by the AgNO3 concentration and temperature. Smaller AgNPs are obtained at lower concentrations of the silver precursor and lower temperatures. The antimicrobial properties of nanohybrids against Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, Gram-positive Staphylococcus aureus, and the yeast Candida albicans were found to be concentration- and time-dependent. C. albicans and S. aureus showed the highest susceptibility to GO-AgNPs. These nanohybrids can be used as nanofillers in polymer nanocomposites to develop materials with antimicrobial activity for applications in different areas, and another potential application could be cancer therapeutic agents.

Effect of Organic Modifier and Clay Content on Non-Isothermal Cold Crystallization and Melting Behavior of Polylactide/Organovermiculite Nanocomposites.

In clay/polymer nanocomposites, the crystallization behavior and kinetics of the polymer can be affected by the presence of clay, its content and the degree of miscibility between the clay and the polymer matrix. The effect of two different organomodified vermiculites on the non-isothermal cold crystallization and melting behavior of polylactide (PLA) was studied by differential scanning calorimetry (DSC). In the presence of vermiculites, the cold crystallization of PLA occurred earlier, particularly for the highest content of the most miscible organovermiculite with PLA. The cold crystallinity of PLA decreased at low heating rates, notably at high organoclay loadings, and increased at high heating rates, especially at low vermiculite contents. According to the crystallization half-time, crystallization rate coefficient (CRC), and crystallization rate parameter (CRP) approaches, the cold crystallization rate of PLA increased by incorporating vermiculites, with the effect being most noteworthy for the vermiculite showing better compatibility. The Mo model was successful in describing the non-isothermal cold crystallization kinetics of the PLA/vermiculite composites. The melting behavior was affected by the heating rate and the type and content of clay. The nucleating effect of the most compatible clay resulted in the less perfect crystallites. The activation energy was evaluated using the Kissinger and Takhor methods.

Effect of Alkyl Chain Length in POSS Nanocage on Non-Isothermal Crystallization Behavior of PCL/Amino-POSS Nanocomposites.

The study of the non-isothermal crystallization behavior of polymers is of great importance due to the effect of degree of crystallinity and crystallization process on the polymer properties. The effect of aminopropylisobutyl polyhedral oligomeric silsesquioxane (APIBPOSS) and aminopropylisooctyl polyhedral oligomeric silsesquioxane (APIOPOSS) on poly(ε-caprolactone) (PCL) crystallization is studied by differential scanning calorimetry (DSC) under non-isothermal conditions and polarized optical microscopy (POM). The crystallization kinetics is analyzed using the Avrami and Mo models, and effective activation energies are evaluated by the Friedman isoconversional method. The results show that the compatibility between polyhedral oligomeric silsesquioxanes (POSS) and PCL and POSS loading affect the crystallization process. A higher crystallization temperature, a narrower size distribution of crystallite, and a faster crystallization rate are obtained in the presence of all the studied contents of APIBPOSS and at lower contents of APIOPOSS. At APIOPOSS contents higher than 2 wt %, the crystallization temperature is lowered, the size distribution of crystallite is broadened, and the crystallization process is retarded. The presence of POSS leads to an increase in the number of nucleation sites, and a reduction in the size of the crystallite and the overall degree of crystallinity, as a result of the confinement of PCL chains caused by POSS nanoparticles.

Multiple Emulsions with Extracts of Cactus Pear Added in A Yogurt: Antioxidant Activity, In Vitro Simulated Digestion and Shelf Life.

Consumers demand so-called natural in which additive and antioxidant preservatives are from natural origin. Research focuses in using extracts from plants and fruits that are rich in bioactive compounds such as phenolics and betalains, but these are also prone to interact with proteins and are exposed to suffer degradation during storage. In this work, we developed a fortified yogurt with the addition of betalains and polyphenols from cactus pear extract encapsulated in a multiple emulsion (ME) (W1/O/W2). Different formulations of ME were made with two polymers, gum arabic (GA) and maltodextrin (MD) and with the best formulation of ME four types of yogurt were prepared using different % (w/w) of ME (0%, 10%, 20% and 30%). Bioactive compounds, antioxidant activity, color and lactic acid bacteria (LAB) were analyzed in the different yogurts over 36 days of shelf life. Furthermore, in vitro simulated digestion was evaluated. The yogurts had significant (p < 0.05) differences and the ME protected the bioactive compounds, activity of antioxidants and color. The ME did not affect the viability of LAB during 36 days of storage. The in vitro digestion showed the best bioaccessibilities of antioxidant compounds with the yogurts with ME.

Nutrición, gastronomía y salud en la comunidad de Castilla y León / Nutrition, gastronomy and health in the community of Castilla y León

Introducción: la gastronomía y los hábitos alimentarios determinan el estado nutricional y de salud de una población. Las peculiaridades geográficas y climatológicas de Castilla y León (CyL) contribuyen al desarrollo de su riqueza cultural y gastronómica. Objetivos: analizar las características gastronómicas de CyL y evaluar las necesidades nutricionales y de salud de la población. Métodos: este estudio es una revisión narrativa. Resultados: en CyL existen más de 50 alimentos acogidos a distintas figuras de calidad, desde legumbres, embutidos, quesos, frutas y hortalizas hasta empanadas y dulces. Asimismo, CyL posee la ratio más elevada de establecimientos de restauración de España. El análisis del perfil calórico revela la tendencia hacia una dieta desequilibrada con exceso de ingesta de lípidos y proteínas en detrimento del consumo de hidratos de carbono complejos. La evaluación del consumo alimentario muestra valores superiores a la media nacional de todos los grupos de alimentos, con especial atención a la carne y derivados, leche y derivados, huevos, cereales y legumbres. En relación con el estilo de vida, se observan mejores valores en los indicadores de sedentarismo, actividad física y obesidad en comparación con el resto de España. Conclusiones: la comunidad de Castilla y Léon posee unas características geográficas y de identidad cultural propias que la convierten en una región de referencia a nivel nacional en relación con la producción y comercialización de productos autóctonos de calidad. Los hábitos alimentarios están asociados con la gastronomía y contribuyen a la promoción de un buen estado nutricional y de nivel de vida de la población

Introduction: gastronomy and eating habits are key factors that determine a population's health and nutritional status. The geographical and climatic peculiarities of Castilla y León (CyL) contribute to the development of its cultural and gastronomic wealth. Objectives: to evaluate the gastronomic characteristics of CyL and assess the population's health and nutritional needs. Methods: this study is a narrative review. Results: in CyL there are more than 50 foods with various figures of quality, from vegetables, meats, cheeses and fruits to pasties and sweets. CyL has also the highest ratio of dining options from Spain. The caloric profile analysis reveals the trend towards an unbalanced diet with excess intake of lipids and proteins to the detriment of the consumption of complex carbohydrates. The assessment of food consumption shows higher values than the average national in all the food groups, with special attention to the meat and derivatives, milk and derived, eggs, cereals and legumes. With regard to lifestyle, best values in indicators of sedentarism, physical activity and obesity are observed in comparison with the rest of Spain. Conclusions: the region of Castilla y León has its own geographical and cultural characteristics that make it a region of reference at the national level in relation to the production and marketing of local products of quality. Eating habits are associated with gastronomy and contribute to the promotion of a good nutritional status and standard of living of the population

Atención prestada por un Centro de Urgencias de Atención Primaria en el atentado terrorista de 2017 en Barcelona (España) / Care provided by a primary care emergency center in the terrorist attack of 2017 in Barcelona (Spain)

Introducción: el 17 de agosto de 2017 se produce en barcelona un atentado terrorista. una furgoneta arrolla a centenares de viandantes en las ramblas alrededor de las 5:00 pm. El centro de urgencias de atención primaria (cuap) ciutat-vella peracamps, que atiende generalmente entre 70 y 100 pacientes diarios, sobretodo de nivel III y IV, según el sistema español de triaje (set), está situado en las inmediaciones donde se produjo el atentado. Objetivo: determinar el perfil de la demanda y la respuesta de los servicios prestados en el cuap las primeras 24h después del atentado. Metodología: estudio cuantitativo, observacional y retrospectivo. Los datos fueron obtenidos de la trayectoria clínica informatizada de enfermería y de la historia clínica electrónica de los pacientes que acudieron en el ámbito temporal de dicho estudio. Resultados: en las primeras 24 horas, el cuap recibió un total de 70 pacientes, de los cuales 25 estuvieron relacionados de forma directa con el atentado. En cuanto a los niveles de triaje de enfermería, un 4% fueron de nivel I (n=1), un 40% fueron nivel III (n=10), y un 56% nivel IV (n=14). Conclusiones: no hubo una mayor demanda asistencial, pero sí un nivel de gravedad superior. En cuanto a los tiempos de asistencia tampoco se observa diferencia con otros días, pero se ha de considerar que se incrementó el número de personal sanitario, lo cual optimizó la asistencia

Introduction: on august 17, 2017, a terrorist attack takes place in barcelona. A van rolls over hundreds of pedestrians on the ramblas in barcelona around 5pm. The emergency center for primary care (cuap) ciutat-vella peracamps, which generally attends between 70 and 100 patients a day, above all at level III and IV, according to the spanish triage system (set); it's located close where the attack took place. Objective: determine the profile of the demand and the response of the services provided in the cuap the first 24 hours after the attack. Methodology: quantitative, observational and retrospective study. The data were obtained from the computerized clinical trajectory of nursing and the electronic clinical history of the patients who attended in the temporal scope of said study. Results: in the first 24 hours, the cuap received a total of 70 patients, which 25 were directly related to the attack. Regarding nursing triage levels, 4% were level i (n = 1), 40% were level iii (n = 10), and 56% level iv (n = 14). Conclusions: there was no greater demand for care, but a higher level of severity. Regarding the attendance times, there is no difference with other days, but it has to be considered that the number of health personnel increased, which optimized the assistance

Conducting Polymer-TiO2 Hybrid Materials: Application in the Removal of Nitrates from Water.

Materials able to produce the reduction of nitrate from water without the need of a metal catalyst and with avoiding the use of gaseous hydrogen have been developed by combining the synergistic properties of titania and two conducting polymers. Polymerization of aniline and pyrrol on titanium dioxide in the presence of two different oxidants/dopants (iron trichloride or potassium persulfate) has been evaluated. The resulting hybrid materials have good thermal stability imparted by the titania counterpart, and a considerable conductivity provided by the conducting polymers. The capability of the hybrid materials of reducing aqueous nitrate has been assessed and compared to the catalytic hydrogenation of nitrate using a platinum catalyst supported on these hybrid synthesized materials. The mechanism of nitrate abatement implies adsorption of nitrate on the polymer by ion exchange with the dopant anion, followed by the reduction of nitrate. The electron transfer from titania to the conducting polymer in the hybrid material favors the reductive ability of the polymer, in such a way that nitrate is selectively reduced with a very low production of undesirable side products. The obtained results show that the activity and selectivity of the catalytic reduction of nitrate with dihydrogen in the presence of a platinum catalyst supported on the hybrid materials are considerably lower than those of the metal-free nanocomposites.

Graphene Based Poly(Vinyl Alcohol) Nanocomposites Prepared by In Situ Green Reduction of Graphene Oxide by Ascorbic Acid: Influence of Graphene Content and Glycerol Plasticizer on Properties.

The enhanced properties of polymer nanocomposites as compared with pure polymers are only achieved in the presence of well-dispersed nanofillers and strong interfacial adhesion. In this study, we report the preparation of nanocomposite films based on poly(vinyl alcohol) (PVA) filled with well dispersed graphene sheets (GS) by in situ reduction of graphene oxide (GO) dispersed in PVA solution using ascorbic acid (L-AA) as environmentally friendly reductant. The combined effect of GS content and glycerol as plasticizer on the structure, thermal, mechanical, water absorption, and water barrier properties of PVA/GS nanocomposite films is studied for the first time. Higher glass transition temperature, lower crystallinity, melting, and crystallization temperature, higher mechanical properties, and remarkable improvement in the thermal stability compared to neat PVA are obtained as a result of strong interfacial interactions between GS and PVA by hydrogen bonding. PVA/GS composite film prepared by ex situ process is more brittle than its in situ prepared counterpart. The presence of GS improves the water barrier and water resistance properties of nanocomposite films by decreasing water vapor permeability and water absorption of PVA. This work demonstrates that the tailoring of PVA/GS nanocomposite properties is enabled by controlling GS and glycerol content. The new developed materials, particularly those containing plasticizer, could be potential carriers for transdermal drug delivery.

Study on the effect of graphene and glycerol plasticizer on the properties of chitosan-graphene nanocomposites via in situ green chemical reduction of graphene oxide.

Unplasticized and glycerol plasticized chitosan/graphene (CS/GS) nanocomposites were synthesized via in situ chemical reduction of graphene oxide sheets (GO) with l-ascorbic acid (L-AA) as reductant by solution casting. The reduction of GO with L-AA was investigated to establish the optimal amount of reductant required to produce chemically reduced graphene sheets (GS). The combine effect of both nanofiller and glycerol on the structure, thermal, mechanical, and electrical properties of CS/GS nanocomposite films was evaluated. Materials were characterized by FT-IR, NMR, UV-Vis, XPS, XRD, Raman, SEM, TEM, and TGA. The results showed that GS sheets were homogeneously dispersed throughout the CS matrix, and that interactions between CS and the surface of GS took place. When compared with neat CS, nanocomposites showed a decrease in the crystallinity, better thermal stability under oxidative atmosphere, and improved mechanical properties, while maintained the thermal properties of CS under inert conditions. Combined use of glycerol and GS led to substantially enhanced mechanical properties. The electrical conductivity was increased with increasing GS loading in nanocomposite. This study demonstrates how CS/GS nanocomposites performance properties can be tailored by controlling GsS and plasticizer content.

PCL/POSS Nanocomposites: Effect of POSS Derivative and Preparation Method on Morphology and Properties.

The incorporation of polyhedral oligomeric silsesquioxanes (POSS) molecules as nanoparticles into polymers can provide improved physico-chemical properties. The enhancement depends on the extent of dispersion of the nanofiller, which is determined by the compatibility with the polymer that is by the POSS type, and the processing method. In this study, poly(ε-caprolactone)/POSS derivatives nanocomposites (PCL/POSS) were obtained via solution-casting and melt compounding. Two amino-derivatives containing different alkyl substituents, and ditelechelic POSS-containing hybrid PCL masterbatch were used as nanofillers. The effect of preparation method, POSS content and type on the morphology, thermal, mechanical, and surface properties of nanocomposites were studied. Morphological analysis evidenced the formation of POSS crystalline aggregates, self-assembled POSS molecules of submicrometer size dispersed in the polymer matrix. The best dispersion was achieved using the ditelechelic POSS-containing hybrid PCL masterbatch, and comparing the two amino-POSS derivatives, the one with longer alkyl chain of substituents exhibited better degree of dispersion independent of preparation method. DSC analysis showed the role of POSS derivatives as nucleating agents for PCL. The incorporation of POSS derivatives into the PCL matrix improved thermal stability. The preparation method, POSS type and content had influence on mechanical properties of nanocomposites. POSS nanoparticles enhanced the surface hydrophobicity of PCL.

Surfactant-assisted synthesis of conducting polymers. Application to the removal of nitrates from water.

Three different conducting polymers, polythiophene (PT), polypirrol (PPY) and polyaniline (PANI) have been synthesized via oxidative chemical polymerization in aqueous media, in such a way that the synthesis protocol did not involve any toxic solvents. They have been tested in the abatement of nitrates from an aqueous solution without the need of any metal catalyst. The N-containing polymers (PANI and PPy) were able to remove nitrates to a level that accomplishes the European legislation requirements; however, the nature of each polymer greatly influenced the process mechanism. Whereas ion exchange between Cl- and SO42- counter-ions in the polymer and NO3- from water is the main responsible for the effective nitrate removal in PANI, as assessed by FTIR and XPS analyses, the nitrate removal mechanism on PPy is based in an electron transfer from the polymer to nitrate through N sites located in the pyrrolic ring. On the other hand, PT was not able to exchange nitrate unless it was synthesized with FeCl3 as oxidant/dopant and an anionic surfactant (sodium dodecyl sulfate -SDS-) is used. In that case, the electrostatic attraction between sulfate (OSO3-) groups from the surfactant and Fe3+ ions from FeCl3 produced the anchoring of Cl- to the oxidized PT growing chain, this favoring ion exchange with nitrate in the aqueous solution, followed by a redox process.

Tratamiento quirúrgico de la obesidad: recomendaciones prácticas basadas en la evidencia / Bariatric surgery: Evidence-based practical recommendations

La obesidad mórbida es, habitualmente, refractaria a los tratamientos convencionales, por lo que la modificación de hábitos dietéticos y de actividad física y/o el uso de fármacos consiguen pérdidas de peso parciales con habitual recuperación posterior. La cirugía bariátrica constituye una opción terapéutica para los casos de obesidad con elevado índice de masa corporal(IMC) asociada a comorbilidades, con buenos resultados a corto y largo plazo. El Grupo de Trabajo sobre Obesidad de la Sociedad Española de Endocrinología y Nutrición (GOSEEN) ha elaborado un documento con recomendaciones prácticas basadas en la evidencia para el tratamiento quirúrgico de la obesidad.La revisión se estructura en 3 partes. En la primera se definen los conceptos de obesidad y comorbilidades asociadas, los tratamientos médicos y sus resultados, las indicaciones y contraindicaciones para el tratamiento quirúrgico con los criterios de selección de los pacientes, el manejo pre y perioperatorio y la valoración de grupos especiales, como adolescentes y personas de edad avanzada. En la segunda parte se describen las distintas técnicas quirúrgicas, las vías de acceso y los resultados comparativos, las complicaciones tanto a corto como a largo plazo, la repercusión de la pérdida ponderal sobre las comorbilidades y los criterios para evaluar la efectividad de la cirugía. En la tercera parte se desarrolla el seguimiento postoperatorio, el control dietético en fases tempranas y más tardías tras la cirugía, y el calendario de control médico y analítico con la suplementación de los distintos macro y micronutrientes en función de la técnica quirúrgica empleada. Se incluye un apartado final sobre gestación y cirugía bariátrica, así como tablas y gráficos complementarios al texto desarrollado. La cirugía bariátrica sigue siendo un tratamiento discutido para la obesidad, pero los resultados en la corrección del exceso ponderal con mejoría en las patologías asociadas y en la calidad de vida confirman que puede ser el tratamiento de elección en pacientes seleccionados, con la técnica quirúrgica apropiada y con un correcto control pre y postoperatorio (AU)

Morbid obesity is usually refractory to conventional treatments. Consequently, weight that is lost by modifying diet and exercise and/or the use of drugs is usually later regained. Bariatric surgery constitutes a therapeutic option in obese patients with a high body mass index associated with comorbidities and achieves good results in both the short and the long term. The Obesity Working Group of the Spanish Society of Endocrinology and Nutrition has produced a document with practical, evidence based recommendations for the surgical treatment of obesity .The review is structured in three parts. The first part defines the concepts of obesity and associated comorbidities, medical treatments, their results, and the indications and contraindications for surgical treatment, as well as the criteria for patient selection, pre- and perisurgica lmanagement, and assessment of special groups such as adolescents and the elderly. The second part discusses the different surgical techniques, approaches and comparative results, short- and long-term complications, the repercussions of weight loss on comorbidities, and the criteria for assessing the effectiveness of surgery. The third part discusses postsurgical follow-up, dietary control in the early and subsequent stages after surgery and the schedule for medical and laboratory follow-up, together with the different macro- and micronutrient supplements that should be used depending on the surgical technique employed. A final section is included on pregnancy and bariatric surgery, as well as tables and figures that complement the text. Although bariatric surgery continues to be a questionable treatment for obesity, the results correcting excess weight, with improvements in associated comorbidities and in quality of life, confirm that this option could be the treatment of choice in selected patients when the appropriate surgical technique and correct preandpostoperative follow-up are employed (AU)