Diseño de una ánodo modificado con nanopilares de óxido de zinc y manopartículas de oro para su empleo en celdas fotoelectroquímicas

El tema de investigación que se desarrolló está ligado con el diseño del ánodo de una celda fotoelectroquímica para lograr una mayor eficiencia en la conversión de energía de estos dispositivos. En esta propuesta, se plantea la construcción de un ánodo modificado empleando nanopilares del semiconductor óxido de zinc (ZnO) y nanopartículas de oro (Au) sobre un electrodo de óxido de indio-estaño (ITO), para incrementar el transporte electrónico y disminuir el fenómeno de recombinación de pares electrón-hueco. La efectividad de las celdas fotoelectroquímicas dependerá de varias cosas, entre las que se encuentran la morfología y tamaño de las nanopartículas de Au y los nanopilares de ZnO. Se proyectó generar este ánodo empleando métodos electroquímicos, el cual disminuirían costos, se obtenga de una manera fácil y rápida, que a su vez mejore la eficiencia del trasporte electrónico, para poder emplearse en la construcción de un sistema fotoelectroquímico. Se considera el electrodepósito de nanopilares de ZnO recubiertos por nanopartículas de Au para incrementar los excitones fotogenerados. Para ello, se proponen la variación de condiciones para el diseño y construcción del ánodo, donde todos los sistemas propuestos requieren de un estudio de caracterización morfológica, topográfica, electrónica y óptica, además de un análisis del desempeño del ánodo diseñado por técnicas electroquímicas

Obstrucción de la vía biliar principal secundaria a mieloma de involucro pancreático

ResumenSe presenta el caso de una mujer de 69 años de edad con colangitis aguda, debido a la compresión extrínseca de las vías biliares por el desarrollo de mieloma. El involucro del páncreas secundario a mieloma múltiple es poco común. La paciente se manejó con radioterapia. La reducción del tamaño del tumor y sin recidiva de la colangitis se observaron después de 12 meses.AbstractThe case is presented on a 69 year-old female with acute cholangitis due to extrinsic bile duct compression caused by pancreatic myeloma involvement. Pancreas involvement with multiple myeloma is uncommon. The patient was managed with localised radiotherapy. There was a reduction in tumour size and no recurrence of cholangitis observed after 12 months of follow-up

Modeling and scaling up of the Cr(VI) adsorption process by using mexicalcite natural mineral in a packed bed column

Artículo científicoThe natural mineral known as Mexicalcite is native to the southern region of Mexico, and due to its abundance and accessibility characteristics, as well as its insolubility in water, it is recommended as an adsorbent material. For such reasons, in this work Mexicalcite was used as adsorbent material to remove Cr(VI) in a packed bed column. The effects of the parameters: bed column height (Z), flow rate (Q), and the initial chromium concentration (C0), on the adsorption capacity (q) and removal percentage (%R) were evaluated. The results show minimal changes in adsorption capacity, specifically a 4% difference; with a mean value of 4.98 mg/g. However, maximum removal percentage was obtained for a high height in the bed column, where there is more contact time. However, low removal percentages were obtained for high flow rate, where the contact time is considerably less. The maximum removal was 94.09%, which was obtained with the highest packed bed height (Z= 6cm), initial concentration (C0= 25 mg/L), and lowest flow rate (Q= 2mL/min). The process was modeled using the Thomas, Adams-Bohart and Yoon-Nelson models. With the BDST model, it was possible to scale up the adsorption process and double the original column dimensions. In addition, the column dimensions were obtained theoretically, to operate continuously for 120 h. Finally, the chromium concentration at the outlet was 0.1 mg/L, using a value of 2 for the bed height/column diameter ratio (Z/d)

Morphological and Physicochemical Characterization of Agglomerates of Titanium Dioxide Nanoparticles in Cell Culture Media

Titanium dioxide nanoparticles (TiO2 NP) are possible carcinogenic materials (2B-IARC) and their toxicity depends on shape, size, and electrical charge of primary NP and on the system formed by NP media. The aim of this work was to characterize agglomerates of three TiO2 NP by evaluating their morphometry, stability, and zeta potential (ζ) in liquid media and their changes with time. Sizes of agglomerates by dynamic light scattering (DLS) resulted to be 10–50 times larger than those obtained by digital image analysis (DIA) given the charged zone around particles. Fractal dimension (FD) was highest for agglomerates of spheres and belts in F12K, and in E171 in FBS media. E171 and belts increased FD with time. At time zero, using water as dispersant FD was larger for agglomerates of spheres than for of E171. Belts suspended in water had the smallest values of circularity (Ci) which was approximately unchanged with time. All dispersions had ζ values around −30 mV at physiological pH (7.4) and dispersions of NP in water and FBS showed maximum stability (Turbiscan Lab analysis). Results help in understanding the complex NP geometry-size-stability relationships when performing in vivo and in vitro environmental-toxicity works and help in supporting decisions on the usage of TiO2 NP

Publicidad en la revista Proa durante los años cincuenta. Estudio gráfico e inventariado

More than a half of the pages from any classic issue of Proa Magazine are dedicated to advertising. Although it is a vital content for Proa, it has been traditionally treated as secondary material. Through a graphic study and an inventory, this research provides data about which design technics were used for the elaboration of the adverts, which were its references, what kind of companies advertised and what commitment did they have with the Colombian architectural associations of that time. This study shows the importance of advertising in Proa as a primary source of documentation, and tests research tools that could be applied to the analysis of advertising in architecture magazines outside the Colombian context

Diverse Large HIV-1 Non-subtype B Clusters Are Spreading Among Men Who Have Sex With Men in Spain

In Western Europe, the HIV-1 epidemic among men who have sex with men (MSM) is dominated by subtype B. However, recently, other genetic forms have been reported to circulate in this population, as evidenced by their grouping in clusters predominantly comprising European individuals. Here we describe four large HIV-1 non-subtype B clusters spreading among MSM in Spain. Samples were collected in 9 regions. A pol fragment was amplified from plasma RNA or blood-extracted DNA. Phylogenetic analyses were performed via maximum likelihood, including database sequences of the same genetic forms as the identified clusters. Times and locations of the most recent common ancestors (MRCA) of clusters were estimated with a Bayesian method. Five large non-subtype B clusters associated with MSM were identified. The largest one, of F1 subtype, was reported previously. The other four were of CRF02_AG (CRF02_1; n = 115) and subtypes A1 (A1_1; n = 66), F1 (F1_3; n = 36), and C (C_7; n = 17). Most individuals belonging to them had been diagnosed of HIV-1 infection in the last 10 years. Each cluster comprised viruses from 3 to 8 Spanish regions and also comprised or was related to viruses from other countries: CRF02_1 comprised a Japanese subcluster and viruses from 8 other countries from Western Europe, Asia, and South America; A1_1 comprised viruses from Portugal, United Kingom, and United States, and was related to the A1 strain circulating in Greece, Albania and Cyprus; F1_3 was related to viruses from Romania; and C_7 comprised viruses from Portugal and was related to a virus from Mozambique. A subcluster within CRF02_1 was associated with heterosexual transmission. Near full-length genomes of each cluster were of uniform genetic form. Times of MRCAs of CRF02_1, A1_1, F1_3, and C_7 were estimated around 1986, 1989, 2013, and 1983, respectively. MRCA locations for CRF02_1 and A1_1 were uncertain (however initial expansions in Spain in Madrid and Vigo, respectively, were estimated) and were most probable in Bilbao, Spain, for F1_3 and Portugal for C_7. These results show that the HIV-1 epidemic among MSM in Spain is becoming increasingly diverse through the expansion of diverse non-subtype B clusters, comprising or related to viruses circulating in other countries

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

Aplicación Web para automatizar la administración e inventario del negocio "El Chompipe" en el Mercado "El Bisne" de Chinandega

Tesis (Ing. en Sistemas de Información)-Universidad Nacional Autónoma de Nicaragua, León.UNAN-Leó

Salmonella sp Group A: A rare cause of bacterascites. A case report

Bacterascites (BA) is a minimally studied and defined entity. Its prognosis and clinical course are not well defined, and currently there are no management guidelines. We present a rare cause of BA in which Salmonella sp group A was isolated in a 44 year old man with cirrhosis who had diarrhea and fever three days earlier. Treatment with intravenous ceftriaxone was effective