Application of percutaneous endoscopic gastrostomy in ent patients

[ES] INTRODUCCIÓN: La gastrostomía en los pacientes oncológicos de cabeza y cuello permite un apropiado aporte nutricional y por tanto un buen estado general, lo que facilita una mejor tolerancia y cumplimiento de los tratamientos. DISCUSIÓN: La PEG (gastrostomía endoscópica percutánea) es una buena opción para la nutrición de nuestros pacientes que presenta importantes ventajas, tanto por la baja morbimortalidad que presenta la técnica como por la buena aceptación social, evitando los problemas nasales y esofágicos y por el bajo coste que supone. Se realiza un repaso de las principales indicaciones ORL que pueden precisar esta técnica. CONCLUSIÓN:En nuestro servicio se realiza la gastrostomía percutánea a los pacientes oncológicos que requieren nutrición enteral durante más de 8 semanas. Su tolerancia por parte del paciente es buena y las complicaciones generalmente menores. La PEG debería sustituir a la sonda nasogástrica y a la gastrostomía quirúrgica en un futuro en pacientes con esperanza de vida limitada. [EN] INTRODUCTION: Gastrostomy is a very useful technique to maintain an adequate nutritional status in patients with head and neck cancer. It presents very good acceptability and complete adherence of treatments. DISCUSSION: PEG is a good nutritional option for our oncological patients. It is a minimally invasive method with low morbility and mortality rates, low economical cost and very good social acceptability. We summarize the main ENT indications of this technique. CONCLUSION: Our department indicate the percutaneous endoscopic gastrostomy in patients with head and neck cancer who are unable to maintain an adequate nutritional status and need enteral nutrition for more than 8 weeks. Its acceptability is very good and complications are generally minor ones. Percutaneous endoscopic gastrostomy should replace to nasogastric feeding tubes and to open gastrostomy in patients with short life expectancy

Materiales de carbono micro-mesoporosos obtenidos mediante nanomoldeo

Tesis doctoral presentada en el Departamento de Química Orgánica e Inorgánica de la Universidad de Oviedo. Mayo de 2013[EN] The main aim of the present work is to develop new synthetic methods that allow the preparation of carbon materials with an ordered structure and bimodal porosity in the micro-mesopore range. To this end, three different approaches, using nanocasting as pore control technique, have been followed: i) microporosity development, by physical or chemical activation, in ordered mesoporous carbons ii) replication of micro-mesoporous alumininosilicates by chemical vapor deposition and iii) "one-pot" synthesis of hierarchical carbons by co-assembly of silicates, block copolymers and carbon precursors derived from biomass. In the three mentioned methods it was performed a systematic study of the preparation variables and they have been related with the porosity and structure of the obtained carbons. Physical activation of ordered mesoporous carbons results in a considerable microporosity increase and a collateral mesoporosity widening. In the case of chemical activation, microporosity increases with increasing activation temperature and/or activating agent proportion; nevertheless, at strong activation conditions it causes great deterioration of the ordered mesoporous network. To solve this problem, a novel method involving the direct activation of the carbon/template composite was proposed. Thus, carbons with a hierarchical porosity and surface areas up to 1700 m2/g were achieved whilst the ordered mesostructure was preserved. The second route accomplishes a real control of both the porosity and the structure. Hierarchical aluminosilicates with microporous core and mesoporous shell were prepared. Optimum infiltration conditions were established in order to correctly infiltrate both micro and mesoporosity of the prepared templates. Using this strategy carbons with core/shell structure and surface areas from up to 1323 m2 /g were obtained. In the third route the interactions between the structure directing agent, the silica precursor and the carbon precursor were adjusted by varying synthesis conditions of a sol-gel process in order to obtain hierarchical carbons. The main advantage of this route is its simplicity since it is a “one-pot” process.[ES] El presente trabajo tiene como objetivo principal el desarrollo de nuevos métodos de síntesis que permitan la preparación de materiales de carbono con una estructura ordenada y con una porosidad bimodal en el intervalo de los micro-mesoporos. Para ello, se han abordado tres metodologías diferentes cuyo denominador común ha sido el uso del nanomoldeo como técnica de control de tamaño de poro: i) desarrollo de la microporosidad, mediante activación física o química, en carbones mesoporosos ordenados; ii) replicación mediante depósito de carbono en fase vapor de aluminosilicatos micro-mesoporosos y iii) síntesis “one-pot” de carbones jerárquicos mediante el co-ensamblaje de silicatos, copolímeros de bloque y precursores de carbono derivados de la biomasa. En los tres métodos se ha llevado a cabo un estudio sistemático de las variables de preparación y se han relacionado éstas con la porosidad y la estructura de los carbones obtenidos. La activación física de carbones mesoporosos ordenados produce un considerable aumento de la microporosidad y un ensanchamiento colateral de la mesoporosidad. En el caso de la activación química, la microporosidad aumenta al aumentar la temperatura de activación y la cantidad de agente activante, pero provoca un gran deterioro de la estructura mesoporosa ordenada cuando las condiciones de activación son fuertes. Para solventar este problema, se planteó una metodología novedosa consistente en la activación directa del material compuesto carbón/plantilla. Así, se consiguen preparar carbones jerárquicos con superficies específicas mayores de 1700 m2/g preservando la estructura ordenada de los mismos. La segunda ruta permitió ejercer un verdadero control tanto de la porosidad como de la estructura. Se prepararon aluminosilicatos formados por un núcleo microporoso de zeolita y una capa mesoporosa de sílice ordenada. Se establecieron las condiciones óptimas para la infiltración de tanto la micro como la mesoporosidad de estas plantillas. Mediante esta estrategia se obtuvieron carbones altamente ordenados con estructura núcleo/ corteza y con áreas superficiales de hasta 1323 m2/g En la tercera ruta se ajustan las interacciones entre el agente director de estructura, el precursor de silicio y el precursor carbonoso mediante la variación de las condiciones de síntesis en un proceso sol-gel. La principal ventaja de esta última ruta es su simplicidad ya que es un proceso “one-pot” mediante el cual se obtuvieron de manera sencilla carbones con porosidad jerárquicaPeer reviewe

Driving the sodium-oxygen battery chemistry towards the efficient formation of discharge products: The importance of sodium superoxide quantification

Sodium-oxygen batteries (SOBs) have the potential to provide energy densities higher than the state-of-the-art Li-ion batteries. However, controlling the formation of sodium superoxide (NaO2) as the sole discharge product on the cathode side is crucial to achieve durable and efficient SOBs. In this work, the discharge efficiency of two graphene-based cathodes was evaluated and compared with that of a commercial gas diffusion layer. The discharge products formed at the surface of these cathodes in a glyme-based electrolyte were carefully studied using a range of characterization techniques. NaO2 was detected as the main discharge product regardless of the specific cathode material while small amounts of Na2O2⋅2H2O and carbonate-like side-products were detected by X-ray diffraction as well as by Raman and infrared spectroscopies. This work leverages the use of X-ray diffraction to determine the actual yield of NaO2 which is usually overlooked in this type of batteries. Thus, the proper quantification of the superoxide formed on the cathode surface is widely underestimated; even though is crucial for determining the efficiency of the battery while eliminating the parasitic chemistry in SOBs. Here, we develop an ex-situ analysis method to determine the amount of NaO2 generated upon discharge in SOBs by transmission X-ray diffraction and quantitative Rietveld analysis. This work unveils that the yield of NaO2 depends on the depth of discharge where high capacities lead to very low discharge efficiency, regardless of the used cathode. We anticipate that the methodology developed herein will provide a convenient diagnosis tool in future efforts to optimize the performance of the different cell components in SOBs.M.E., L.M and N.O.-V. thank the European Union (Graphene Flagship-Core 3, Grant number 881603) for the financial support of this work. J.I.P. acknowledges funding by the Spanish Ministerio de Ciencia, Innovación y Universidades (MICINN), Agencia Estatal de Investigación (AEI) and the European Regional Development Fund (ERDF) through project RTI2018-100832-B-I00. R.Y. acknowledges financial support from StandUp for Energy and the Swedish Energy Agency.Peer reviewe

Effect of nanostructure on the supercapacitor performance of activated carbon xerogels obtained from hydrothermally carbonized glucose-graphene oxide hybrids

Activated carbon xerogels with a cellular morphology were obtained from hydrothermally carbonized glucose-graphene oxide (GO) hybrids and tested as supercapacitor electrodes. The effect of the chemical activation (using KOH) on the nanometer-scale morphology, local structure, porous texture and surface chemistry of the resulting carbon materials was investigated and correlated with their electrochemical behaviour. The electrochemical performance of the activated xerogels was studied in a three-electrode cell using 1 M H2SO4 as the electrolyte. The results underlined the relevant role played by the xerogel nanomorphology; more specifically, xerogels with cellular structures exhibiting well-connected, continuous and very thin (∼5–15 nm) carbon walls (prepared with lower amounts of activating agent) favored ionic diffusion and electronic conduction compared to materials with broken, thicker walls (obtained from higher amounts of activating agent). The effect of nanomorphology and local structure was also made apparent when the xerogels were used as actual supercapacitor electrodes. Particularly, a symmetric capacitor assembled from a carbon xerogel with very thin walls and relatively high graphitic character delivered a much higher specific capacitance than that of a commercial activated carbon (223 vs 153 F g−1 at 100 mA g−1) as well as a significantly improved retention of capacitance at high current densities.This work was financed by QREN, ON2, FCT and FEDER (Project NORTE-07-0124- FEDER-000015 and NORTE-07-0162-FEDER-000050), and co-financed by FCT and FEDER through COMPETE 2020 (Project UID/EQU/50020/2013 - POCI-01-0145- FEDER-006984). Partial funding of this work by the Spanish MINECO and the European Regional Development Fund (projects MAT2015-69844-R and MAT2012- 34011) is also gratefully acknowledged.Peer reviewe

Increasing the efficiency and cycle life of Na-O2 batteries based on graphene cathodes with heteroatom doping

To overcome the challenges of Na-O2 batteries with respect to efficiency, capacity, and cycle life as well as to develop cheap, metal-free, and abundant electrocatalysts, we explored boron and nitrogen-functionalized graphene aerogels prepared by the hydrothermal self-assembly of graphene oxide with subsequent thermal reduction. The results showed an improve of both the cycling overpotential and the coulombic efficiency for the functionalized graphene aerogels. However, the nitrogen-containing cathode presented a shortened cycle life and decreased charging stability. The postmortem analysis of the full discharge, and the full discharge and charge cathodes demonstrated that nitrogen functionalization triggered the formation of solid parasitic products that passivate the cathode surface, thus resulting in a poorer electrochemical performance. By contrast, functionalization with boron-containing groups demonstrated to be a more promising strategy due to minimized parasitic products, leading to lower oxygen reduction and evolution overpotentials with a concomitantly enhanced cell efficiency vs. the undoped cathodes. This resulted in a cycle life of 70 cycles at a relatively high current density of 0.1 mA cm−2 with a capacity cut-off of 0.5 mAh cm−2. Our study underscores that functionalization with heteroatoms simultaneously alters multiple characteristics of graphene-based materials, including their chemistry, texture and morphology, which in turn presents a critical impact on the electrochemical response of the resultant Na-O2 cells.This work was funded by the European Union (Graphene Flagship-Core 3, Grant number 881603) and the Basque Country Government (CIC energiGUNE’20 of the ELKARTEK program, N° Exp. KK-2020/0078). J.I.P. and S.V.-R. acknowledge funding by the Spanish Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación (MCIN/AEI/ 10.13039/501100011033) as well as the European Regional Development Fund (ERDF, A way of making Europe) through grant PID2021-125246OB-I00, and by Plan de Ciencia, Tecnología e Innovación (PCTI) 2018-2022 del Principado de Asturias and the ERDF through grant IDI/2021/000037. N. Ortiz-Vitoriano thanks Ramon y Cajal grant (RYC-2020-030104-I) funded by MCIN/AEI/10.13039/501100011033 and by FSE invest in your future.Peer reviewe