HIT intermediate-band solar cells with self-assembled colloidal quantum dots and metal nanoparticles

The particular opto-electronic properties of chemically synthesized colloidal nanoparticles can be promising for functional materials, as those required for high efficient photovoltaic (PV) devices. In particular, appropriately-designed semiconductor colloids (quantum dots, QDs) can potentially allow sub-bandgap current generation in intermediate-band solar cells; while metal nanoparticles (MNPs) sustaining surface plasmons can provide both near and far-field light trapping to further boost the generated power. However, the incorporation of colloidal particles in inorganic PV materials is not trivial, therefore their implementation has so far been restricted to organic/polymeric based solar cells. In this work, PbS colloidal QDs have been incorporated in the intrinsic a-Si:H layer of HIT (substrate/a-Si:H hetero-junction) test structures. Both c-Si and GaAs substrates have been used, and in some cases colloidal Au NPs have also been included. The obtained devices are meant as probes to verify the feasibility of incorporating foreign nanoparticles in a cell structure and not as potentially efficient solar cells. Despite the radical novelties incorporated, the devices behaved similarly to the references, thus proving the compatibility of the proposed materials and processes

Caracterización fenotípica del ganado criollo en el Parque nacional Huascarán – Ancash

The aim of this study was to evaluate the phenotypic characteristics of the Creole cattle of the Huascarán National Park (PNH), Ancash, Peru through zoometric measurements and indexes of productive interest. The study was conducted in a population of Creole cattle in the Llanganuco zone of the PNH. Data were collected from 32 cows bovines. The zoometric measurements were head width (AC), head length (LC), chest girth (PT), body length (LCU), height withers (ALC) and height at the rump (ALG), anterior rump width (AAG), rear rump with (APG) and rump length (LG). Indexes related to meat ability were calculated: transversal pelvic index (IPT) and longitudinal pelvic index (IPL), and ethnological indexes: anamorphosis index (AI), corporal index (IC), pelvic index (PI) and proportionality index (IPR). The data were processed with the statistical program R. The colour and pattern of the coat were registered applying the nomenclature for Spanish bullfighting cattle. The zoomometric measurements showed a low CV (4.29 – 9.25), except for APG (14.75), reflecting morphological uniformity in the sample. The zoometric indices showed CV less than 10% (5.89 – 7.11), except for the AI ​​(16.28) and IC (11.5). As for the coat, a tendency towards simple colours (46.9%) with a predominance of black was observed. In general, the Creole bovine of the Quebrada de Llanganuco presents similar indexes with the Creole bovine from Ayacucho, Peru, classifying it as a short-bodied animal.El objetivo del presente estudio evaluar las características fenotípicas del ganado criollo del Parque Nacional Huascarán (PNH), Ancash, Perú, mediante la determinación de mediciones zoométricas e índices de interés productivo. El estudio se realizó en una población de bovinos criollos en la quebrada de Llanganuco del PNH. Se colectaron datos de 32 bovinos hembra adultos. Las medidas zoométricas tomadas fueron ancho (AC) y largo (LC) de cabeza, perímetro torácico (PT), largo de cuerpo (LCU), alzada a la cruz (ALC) y a la grupa (ALG), ancho anterior (AAG) y posterior de grupa (APG) y largo de grupa (LG). Se calcularon índices asociados a capacidad cárnica: índice pelviano transversal (IPT) e índice pelviano longitudinal (IPL), e índices etnológicos: índice de anamorfosis (IA), índice corporal (IC), índice pelviano (IP) e índice de proporcionalidad (IPR). Los datos fueron procesados con el programa estadístico R. Se registró el color y patrón del pelaje aplicando la nomenclatura para ganado de lidia. Las medidas zoométricas mostraron un bajo CV (4.29 – 9.25), excepto para APG (14.75), reflejando uniformidad morfológica en la muestra. Los índices zoométricos mostraron CV menores al 10% (5.89 – 7.11), excepto para el IA (16.28) e IC (11.5). En el pelaje se observó una tendencia hacia los colores simples (46.9%) con predominio del negro. En general, el bovino criollo de la Quebrada de Llanganuco presenta índices similares con el bovino criollo de Ayacucho, Perú, clasificándolo como un animal brevilíneo

Metal–Organic Frameworks as Drug Delivery Platforms for Ocular Therapeutics

Metal–organic frameworks (MOFs) have been evaluated as potential nanocarriers for intraocular incorporation of brimonidine tartrate to treat chronic glaucoma. Experimental results show that UiO-67 and MIL-100 (Fe) exhibit the highest loading capacity with values up to 50–60 wt %, whereas the performance is quite limited for MOFs with narrow cavities (below 0.8 nm, for example, UiO-66 and HKUST-1). The large loading capacity in UiO-67 is accompanied by an irreversible structural amorphization in aqueous and physiological media that promotes extended release kinetics above 12 days. Compared to the traditional drawbacks associated with the sudden release of the commercial drugs (e.g., ALPHAGAN), these results anticipate UiO-67 as a potential nanocarrier for drug delivery in intraocular therapeutics. These promising results are further supported by cytotoxicity tests using retinal photoreceptor cells (661W). Toxicity of these structures (including the metal nodes and organic ligands) for retinal cells is rather low for all samples evaluated, except for HKUST-1.Authors would like to acknowledge the financial support from MINECO (MAT2016-80285-p), GV (PROMETEOII/2014/004), and H2020 (MSCA-RISE-2016/NanoMed Project). J.G.-L. acknowledges GV (GRISOLIAP/2016/089) for the research contract. N.C. acknowledges the financial support from MINECO (MINECO-FEDER-BFU2015-67139-R), ISCIII (RETICS-FEDER RD16/0008/0016), and GV (Prometeo 2016/158). I.O.-L. acknowledges Ministerio de Educación, Spain (FPU 14/03166)

Aplicación de normas internacionales de información financiera en las microempresas del sector comercial de santa marta

Se muestra el proceso que ha surgido desde la implementación de las Normas Internacionales de Información Financiera (NIIF) en Colombia, principalmente en las microempresas del sector comercial de Santa Marta.The process that has emerged since the implementation of the International Financial Reporting Standards (IFRS) in Colombia is shown, mainly in the micro-enterprises of the commercial sector of Santa Marta.Agradecimientos -- Prólogo -- Introducción -- Referenciación -- Aspectos Metodológicos -- Instrumento de Recolección de Información -- Resultados -- Conclusionesna27 página

Biocompatibility and Biomechanical Effect of Single Wall Carbon Nanotubes Implanted in the Corneal Stroma: A Proof of Concept Investigation

Corneal ectatic disorders are characterized by a progressive weakening of the tissue due to biomechanical alterations of the corneal collagen fibers. Carbon nanostructures, mainly carbon nanotubes (CNTs) and graphene, are nanomaterials that offer extraordinary mechanical properties and are used to increase the rigidity of different materials and biomolecules such as collagen fibers. We conducted an experimental investigation where New Zealand rabbits were treated with a composition of CNTs suspended in balanced saline solution which was applied in the corneal tissue. Biocompatibility of the composition was assessed by means of histopathology analysis and mechanical properties by stress-strain measurements. Histopathology samples stained with blue Alcian showed that there were no fibrous scaring and no alterations in the mucopolysaccharides of the stroma. It also showed that there were no signs of active inflammation. These were confirmed when Masson trichrome staining was performed. Biomechanical evaluation assessed by means of tensile test showed that there is a trend to obtain higher levels of rigidity in those corneas implanted with CNTs, although these changes are not statistically significant (p > 0.05). Implanting CNTs is biocompatible and safe procedure for the corneal stroma which can lead to an increase in the rigidity of the collagen fibers.The authors would like to acknowledge Professor K. Kaneko for the supply of the SWCNTs. They will also like to acknowledge the support of the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER funds under the project MAT2012-38359-C03-01. This publication has been sponsored in part with the funding of the framework of the Red Tematica de Investigacion Cooperativa en Salud (RETICS), Reference no. RD12/0034/0007, financed by the Instituto Carlos III-General Subdirection of Networks and Cooperative Investigation Centers (R&D&I National Plan 2008-2011) and the European Regional Development Fund (Fondo Europeo de Desarrollo Regional FEDER).Vega-Estrada, A.; Silvestre-Albero, J.; Rodríguez, AE.; Rodríguez-Reinoso, F.; Gómez-Tejedor, JA.; Antolinos Turpín, CM.; Bataille, L.... (2016). Biocompatibility and Biomechanical Effect of Single Wall Carbon Nanotubes Implanted in the Corneal Stroma: A Proof of Concept Investigation. Journal of Ophthalmology. 2016:1-8. https://doi.org/10.1155/2016/4041767S18201

Procedimiento y sistema para detectar queratocono subclínico

Número de publicación: 2 564 397 Número de solicitud: 201431361Procedimiento y sistema para detectar queratocono subclínico, donde el sistema comprende: - un topógrafo corneal configurado para proporcionar un primer (1) y un segundo conjunto (2) de datos espaciales normalizados asociados a la superficie anterior y posterior de la córnea, y un valor de distancia (8) representativo de la separación entre ambas superficies y; - unos medios de procesamiento configurados para generar una primera (3) y una segunda superficie (4) a partir del primer (1) y segundo conjunto de datos (2), y generar un modelo (7) tridimensional que proporciona al menos un primer parámetro (p1) con información de una primera medida de desviación (16) correspondiente a la distancia existente entre el punto de mayor altura (14) de la segunda superficie (4) respecto de un eje axial (12), y donde los medios de procesamiento están además configurados para detectar un posible queratocono subclínico a partir de la medida proporcionada.Universidad Politécnica de CartagenaUniversidad de Murci

Nuevas consideraciones en el tratamiento de la enfermedad ectásica corneal mediante el empleo de segmentos de anillo corneales intraestromales

La enfermedad ectásica corneal esta comprendida por un grupo de patologías cuya principal característica es el adelgazamiento progresivo de la cornea lo que conlleva a alteraciones morfológicas del tejido con el consecuente deterioro de la función visual del paciente. Dentro del grupo de patologías incluidas en este apartado vamos a encontrar las que tienen un carácter de presentación primaria, como el queratocono y la degeneración marginal pelúcida y por otra parte las que tienen un carácter de presentación secundaria a la cirugía fotorefractiva con excimer láser conocida como ectasia post-LASIK. Históricamente, la enfermedad ectásica corneal se ha clasificado basándose en las alteraciones geométricas que se presentan en el tejido sin tomar en cuenta otros factores morfológicos y biomecánicos vinculados a la función visual del paciente. Existen diferentes alternativas para el tratamiento de le enfermedad ectásica corneal que van desde la adaptación de lentes de contacto hasta técnicas mucho mas complejas e invasivas como la queratoplastia lamelar y penetrante. Los segmentos de anillo corneales intraestromales (ICRS) son dispositivos sintéticos que se implantan en la cornea para inducir un moldeamiento del tejido. Hasta la fecha, se han publicado distintos trabajos de investigación que han demostrado su eficacia en el tratamiento de la enfermedad ectásica corneal, así como la capacidad que tienen estos elementos para retrasar e incluso evitar los procedimientos de queratoplastia. Sin embargo, la eficacia de dicha técnica quirúrgica se fundamenta en clasificaciones que toman en cuanta la geometría del tejido sin valorar la agudeza visual del paciente. Adicionalmente existen muy pocos artículos publicados en la literatura científica que reporten los resultados de esta técnica quirúrgica tras largos periodos de seguimiento. La presente tesis doctoral se desarrolla bajo el modelo de conjunto de publicaciones científicas. Tras analizar la eficacia del implante de ICRS basando su análisis en clasificaciones fundamentadas en la agudeza visual del paciente concluimos que tanto para el queratocono como para la ectasia post-LASIK la mejor indicación es en aquellos pacientes que presentan un serio compromiso de la vision al momento del implante. De la misma manera, aquellos pacientes con buena vision antes de la cirugía no son buenos candidatos al tratamiento con ICRS debido a la perdida de vision que ocurre después del procedimiento quirúrgico. Así mismo, pudimos observar que tras largos periodos de seguimiento, la estabilidad de esta técnica quirúrgica va a depender de la forma evolutiva que presente el queratocono al momento de la cirugía. De esta manera, en aquellos pacientes en los que se haya demostrado la estabilidad de la enfermedad al momento del implante, presentaran muy pocos cambios a lo largo del tiempo. Por otra parte, en aquellos casos con signos clínicos de progresión, no se observa estabilidad del tratamiento tras largos periodos de seguimiento. Por este motivo se sugiere la confirmación de la estabilidad del queratocono antes de ser tratados con ICRS

Accommodative intraocular lenses: where are we and where we are going

Abstract Presbyopia still remains the last frontier of refractive surgery. Its surgical management is under constant evolution due to the limitations that exist today with respect to its management, which is probably in relation with the multifactorial basis in which presbyopia is clinically developed in the human. Until currently, virtually all surgical techniques that have been proposed for its correction are based on the induction of pseudoaccommodation in the presbyopic eye, including multifocality. However, the real restoration of accommodation is more complex, and it has been tried by the use of different, so called, “accommodative” pseudophakic intraocular lenses (AIOL). Overall, the reported results with these lenses by independent authors have been modest in relation with the restoration of the accommodative power of the eye and these modest benefits are usually lost with time due to the long term changes in the capsular bag. This fact made these lenses to be almost abandoned in the last few years, but there are currently other AIOL models being used with innovative mechanisms of action and different anatomical support outside the capsular bag that offer encouraging preliminary results that could bring a new potential of application to these types of lenses. In this article, we will update the modern refractive surgeon about the fundamentals and provide updated information about the outcomes of AIOLs by reviewing the concept of accommodation, the different attempts that have been accomplished in the past, their demonstrated published results in human clinical trials, and the future alternatives that may arrive in the near future

The Post-Ovariectomy Interval Affects the Antidepressant-Like Action of Citalopram Combined with Ethynyl-Estradiol in the Forced Swim Test in Middle Aged Rats

The use of a combined therapy with low doses of estrogens plus antidepressants to treat depression associated to perimenopause could be advantageous. However the use of these combinations is controversial due to several factors, including the time of intervention in relation to menopause onset. This paper analyzes whether time post-OVX influences the antidepressant-like action of a combination of ethynyl-estradiol (EE2) and citalopram (CIT) in the forced swim test (FST). Middle-aged (15 months old) female Wistar rats were ovariectomized and after one or three weeks treated with EE2 (1.25, 2.5 or 5.0 µg/rat, s.c.; −48 h) or CIT (1.25, 2.5, 5.0 or 10 mg/kg, i.p./3 injections in 24 h) and tested in the FST. In a second experiment, after one or three weeks of OVX, rats received a combination of an ineffective dose of EE2 (1.25 µg/rat, s.c., −48 h) plus CIT (2.5 mg/kg, i.p./3 injections in 24 h) and subjected to the FST. Finally, the uteri were removed and weighted to obtain an index of the peripheral effects of EE2 administration. EE2 (2.5 or 5.0 µg/rat) reduced immobility after one but not three weeks of OVX. In contrast, no CIT dose reduced immobility at one or three weeks after OVX. When EE2 (1.25 µg/rat) was combined with CIT (2.5 mg/kg) an antidepressant-like effect was observed at one but not three weeks post-OVX. The weight of the uteri augmented when EE2 was administrated three weeks after OVX. The data suggest that the time post-OVX is a crucial factor that contributes to observe the antidepressant-like effect of EE2 alone or in combination with CIT