Polymeric foams as the matrix of voltammetric sensors for the detection of catechol, hydroquinone, and their mixtures

Producción CientíficaPorous electrodes based on polymethylmethacrylate and graphite foams (PMMA_G_F) have been developed and characterized. Such devices have been successfully used as voltammetric sensors to analyze catechol, hydroquinone, and their mixtures. The presence of pores induces important changes in the oxidation/reduction mechanism of catechol and hydroquinone with respect to the sensing properties observed in nonfoamed PMMA_graphite electrodes (PMMA_G). The electropolymerization processes of catechol or hydroquinone at the electrode surface observed using PMMA_G do not occur at the surface of the foamed PMM_G_F. In addition, the limits of detection observed in foamed electrodes are one order of magnitude lower than the observed in the nonfoamed electrodes. Moreover, foamed electrodes can be used to detect simultaneously both isomers and a remarkable increase in the electrocatalytic properties shown by the foamed samples, produces a decrease in the oxidation potential peak of catechol in presence of hydroquinone, from +0.7 V to +0.3 V. Peak currents increased linearly with concentration of catechol in presence of hydroquinone over the range of 0.37·10−3 M to 1.69·10−3 M with a limit of detection (LOD) of 0.27 mM. These effects demonstrate the advantages obtained by increasing the active surface by means of porous structures.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project AGL2015-67482-R)Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (project VA-011U16

A search for new hot subdwarf stars by means of Virtual Observatory tools

Hot subdwarf stars are faint, blue objects, and are the main contributors to the far-UV excess observed in elliptical galaxies. They offer an excellent laboratory to study close and wide binary systems, and to scrutinize their interiors through asteroseismology, as some of them undergo stellar oscillations. However, their origins are still uncertain, and increasing the number of detections is crucial to undertake statistical studies. In this work, we aim at defining a strategy to find new, uncatalogued hot subdwarfs. Making use of Virtual Observatory tools we thoroughly search stellar catalogues to retrieve multi-colour photometry and astrometric information of a known sample of blue objects, including hot subdwarfs, white dwarfs, cataclysmic variables and main sequence OB stars. We define a procedure to discriminate among these spectral classes, particularly designed to obtain a hot subdwarf sample with a low contamination factor. In order to check the validity of the method, this procedure is then applied to two test sky regions: the Kepler FoV and to a test region of around (RA:225, DEC:5) deg. As a result, we obtained 38 hot subdwarf candidates, 23 of which had already a spectral classification. We have acquired spectroscopy for three other targets, and four additional ones have an available SDSS spectrum, which we used to determine their spectral type. A temperature estimate is provided for the candidates based on their spectral energy distribution, considering two-atmospheres fit for objects with clear infrared excess. Eventually, out of 30 candidates with spectral classification, 26 objects were confirmed to be hot subdwarfs, yielding a contamination factor of only 13%. The high rate of success demonstrates the validity of the proposed strategy to find new uncatalogued hot subdwarfs. An application of this method to the entire sky will be presented in a forthcoming work.Comment: 13 pages, 7 figure

Eficacia del diclofenaco tópico vs. nepafenaco tópico en la reducción del dolor durante la fotocoagulación panretiniana

ResumenPropósitoComparar la eficacia del diclofenaco tópico 0.1% vs. nepafenaco tópico en reducir el dolor asociado a la fotocoagulación panretiniana con láser argón.Material y métodosEnsayo clínico aleatorizado doble enmascarado, 132 pacientes (183 ojos) con diagnóstico de retinopatía diabética proliferativa tratados con fotocoagulación panretiniana. Aleatorización en 2 grupos: diclofenaco y nepafenaco tópicos. Se aplicaron 2 dosis de los analgésicos tópicos previas a la fotocoagulación panretiniana, se evaluó el dolor inmediatamente y 15min después. Se analizó nivel de dolor, efectos adversos y síntomas asociados al finalizar la fotocoagulación retiniana.ResultadosLa mediana de la edad para ambos grupos fue de 55 años, relación H:M de 1:1.4. El nivel de dolor inmediato fue de 35.5 (RIC 14-72) para el nepafenaco y de 45 (RIC 14-70) para el diclofenaco (p=0.48). A los 15min fue de 30 (RIC 4-50) para el nepafenaco y de 20 (RIC 2-50) para el diclofenaco (p=0.48). No hubo diferencias significativas en síntomas asociados entre los grupos ni efectos adversos en la superficie ocular.ConclusionesEl tratamiento previo con nepafenaco y diclofenaco tópicos es igualmente eficaz y seguro para reducir el dolor asociado a la fotocoagulación panretiniana en pacientes con retinopatía diabética proliferativa.AbstractPurposeTo compare the efficacy of topical diclofenac 0.1% vs topical nepafenac in reducing pain associated to argon laser retinal photocoagulationMaterial and methodsDouble blinded, randomized clinical trial. One hundred thirty two patients with diagnosis of proliferative diabetic retinopathy treated with retinal photocoagulation. Randomization in to 2 groups: topical diclofenac and nepafenac. Before retinal photocoagulation 2 doses of topical non-steroidal anti-inflammatory drugs were applied, pain was assessed immediately and 15minutes after. Level of pain, adverse effects and associated symptoms at the end of retinal photocoagulation were analyzed.ResultsThe median for age in both groups was 55 years, M:F ratio of 1:1.4. The immediate level of pain was 35.5 (ICR 14-72) for nepafenac and 45 (ICR 14-70) for diclofenac (P=.48). At 15minutes the pain level was 30 (ICR 4-50) for nepafenac and 20 (ICR 2-50) for diclofenac. There was no difference in associated symptoms or adverse effects among groups.ConclusionsThe preventive treatment with topical nepafenac and diclofenac is equally effective and safe for reducing the pain associated with retinal photocoagulation in patients with proliferative diabetic retinopathy

Las bibliotecas públicas cubanas en el período 1959-1976

The phenomena influencing on the creation, functioning and development of public libraries in Cuba are analyzed, the work done in the analysis of public libraries as a whole is fundamented, and a chronological approach to the development of public libraries as a system is made. The topic is dealt with from the point of view of the library as a vehicle for cultural promotion and not just as an information source; besides, the existence and development of public libraries are linked to the social, political and cultural advance of our country and its population

Structural and electrochemical properties of Li-Ni-Co oxides synthesized by wet chemistry via a succinic-acid-assisted technique

[Abstract] Lithiated metal oxides LiCo1−yNiyO2 were synthesized by a sol–gel method using succinic acid as chelating agent. Microcrystalline materials were formed by calcination in oxygen at 800°C. The physicochemical properties of the powders (crystallinity, lattice constants, size grain) has been investigated in the compositional range 0≤y≤1. Structural studies show that a layered single phase was obtained. The local cationic environment has been studied by Raman and FTIR spectroscopy. The changes in the vibrational spectra are well related to those observed by X-ray diffraction. It is shown that the lithium predominant layers are preserved in the entire range of substitution. Pelletized LiCo1−yNiyO2 powders (0.2≤y≤1.0) were tested in Li//LiCo1−yNiyO2 cells by galvanostatic titration. These cells have an initial capacity of 140 mAh/g in the voltage range 2.8–4.2 V and show attractive charge–discharge profiles upon cycling.Spanish and French Foreign Office; PAI Picasso 00717TCSpanish and French Foreign Office; HF1999-010

Complicaciones a corto plazo de la artroplastia total primaria de cadera

Objetivos: Se pretende analizar las principales complicaciones a corto plazo (seis semanas) tras la Artroplastia total primaria de cadera. ;aterial y métodos: Se revisaron todos los pacientes a los que se realizó artroplastia total de cadera durante el año 2003. Las variables estudiadas fueron el índice de luxaciones, sangrado, infección, fracturas periprotésicas, complicaciones vásculo-nerviosas y mortalidad. Resultados: Obtuvimos una tasa del 4,4% de luxaciones; 1,7% de trombosis venosa profunda con un 0,87% de embolismo pulmonar, 1,7% de infecciones superficiales sin casos de infección profunda. El 14,9% de los casos necesitaron una transfusión postquirúrgica. Intraoperatoriamente observamos apertura del cálcar en el 3,5%, y fracturas periprotésicas postoperatorias en el 0,87%. No registramos complicaciones neurológicas ni mortalidad en estas primeras seis semanas del estudio. Conclusiones: La complicación más frecuente es la luxación, fundamentalmente en los casos secundarios a fractura. La trombosis venosa profunda, a èsar de la profilaxis, continúa siendo una complicación frecuente.Objectives: Our purpose was to analyze the main early complications (six weeks) after primary total hip arthroplasty. Materials and Methods: All patients who had undergone primary total hip replacement during 2003 were reviewed. The studied outcomes were the rates of dislocation, blood loss, infection, periprosthetic fractures, neural and vascular complications, and mortality. Results: Our rates were 4,4% for hip dislocation, 1,7% for deep vein thrombosis with 0,87% for pulmonary embolism, 1,7% for wound infection without cases of deep infection. 14,9% of the patients needed postoperative transfusion. We reported 3,5% fractures of the calcar during surgery and 0,87% of postoperative periprosthetic fractures. We didn ́t reported any neural complications or mortality within six weeks postoperatively. Conclusions: The most frequent complication is dislocation, mainly in cases whose underlying diagnose was hip fracture. Although prophylaxis is done, deep vein thrombosis goes on being a frequent complication