Dispersión de rayos X aplicado al análisis de nanotubos de carbono, polímeros y nanocompuestos

[EN] In this review we will show that wide and small angle X-ray scattering techniques (WAXS and SAXS respectively) can be a valuable tool to characterize the structure of carbon nanotubes (CNT) and related CNT-polymer nanocomposites at different characteristic length scales. Ranging from single carbon nanotubes to aggregates of CNTs X-ray scattering may offer structural information which can be crucial in order to design new materials based on carbon nanotubes.[ES] En este trabajo de revisión mostramos que las técnicas de dispersión de rayos X a alto y bajo ángulo (WAXS y SAXS respectivamente) pueden ser una herramienta muy valiosa para caracterizar la estructura de nanotubos de carbono (CNT) y nanocompuestos CNT-polímero, en diferentes escalas de longitud. La dispersión de rayos X puede ofrecer información estructural en el rango desde nanotubos de carbono aislados, hasta agregados de CNT. Dicha información puede ser crucial de cara a diseñar materiales basados en nanotubos de carbono.The authors thank the financial support from the MCYT (grant MAT2005-01768), Spain. The help of G. Broza, Z. Roslaniec, K. Schulte, I. Sics, B. H. Hsiao, S. S. Funari in different parts of this work is gratefully acknowledge. M. C. G.-G. and A. N. are also grateful to the Ramón y Cajal Program for the support of this reserach­.Peer reviewe

Testing of the CHEMTAX program in contrasting Neotropical lakes, lagoons, and swamps

ABSTRACT: The problem using the CHEMTAX program in freshwater environments is that the few matrices of pigment ratios available have not been tested in a wide range of environments. Sixteen Amazonian, Andean, and Caribbean lakes, lagoons, and swamps were sampled over a year. The aim was to determine if it was possible to obtain a reliable matrix of input pigment ratios that may be used in freshwater habitats with different environmental conditions. There were no clear differences among regions for most of the ratios of marker pigments to Chlorophyll a (Chl a) in most of the phytoplankton groups. Only the zeaxanthin/Chl a ratio showed clear variations among areas. The estimates for the mean relative contribution of each phytoplankton group calculated for the pigment ratios obtained in each separate habitat and season were very similar to the estimates calculated using the average pigment ratio obtained for all habitats and seasons. Our study suggests that the matrix of the average pigment ratio obtained in this study can be used to estimate phytoplankton class abundances with the CHEMTAX program in freshwater habitats with different limnological conditions

Information & Technology Magazine. Volume 1 No. 1 April 1998

Hace apenas algunos años muchos de nosotros soñábamos con un año 2000 parecido al descrito en algunas de nuestras novelas preferidas de ciencia ficción, naves espaciales encima de los cielos Colombianos, acceso público a viajes espaciales, marcianos inundando nuestros sanandresitos y demás aspectos relacionados especialmente con cambios sustanciales en las formas de transporte y uso del espacio, debido a que para esta época eran nuestra mayor preocupación.RESEÑA HISTORICA FACULTAD INGENIERIA DE SISTEMAS GESTION DE LA INFORMACION INGENIERIA CIENCIA EDUCACION EN INGENIERIA FACULTAD INFORME ESPECIALJust a few years ago many of us dreamed of a year 2000 similar to the one described in some of our favorite science fiction novels, spaceships above the Colombian skies, public access to travel space, Martians flooding our sanandresitos and other aspects related especially to substantial changes in the forms of transportation and use of space, because at this time they were our greatest concern.Modalidad Presencia

Design and construction of a prototype of potenciostato galvanostato for the corrosion laboratory of the school of metallurgical engineering

The current circumstances motivate the University as an axis of regional development, to propose alternatives that enable it to develop dynamically and as a manager of its own evolution. It is thus making a first attempt to implement policies of import substitution and strategies to minimize the cost of equipment, (E3T) and of Metallurgical Engineering and Materials Science (EIMCM), are currently developing a project for the construction of UIS equipment, which will allow the completion of laboratory activities and that can be reviewed and repaired on the spot. The present article explains the process followed for the design and construction of a first prototype to be implemented in the corrosion laboratory of the EIMCM, which has been called the Galvanostat Autonomous Power System (SPGA). An Autonomous Galvanostat Potentiostat System is defined as an equipment that allows to perform electrochemical tests for purposes of assessing corrosion in a material; either by supplying a controlled potential difference and by sensing the current flowing through an electrochemical cell (Potentiostat mode) or by supplying a controlled current by sensing the potential difference at the terminals of the cell (Galvanostat mode), automatically recording the values ​​at length of the test, indicating abnormal situations and deactivating the equipment when the conditions so require, also offering the possibility of transmitting the data to a pey and generating the visualization of the data to allow observations and conclusions about the test.Las actuales circunstancias motivan a la Universidad como eje de desarrollo regional, a plantearalternativas que lepermitan desenvolverse con dinamismo y como gestora de su propia evolución.Es así que haciendo un primer intento por aplicar políticas de substitución de importaciones yestrategias para minimizar el costo de equipos, de su mantenimiento y de su reparación, decomún acuerdo las escuelas de Ingeniería Eléctrica, Electrónica y Telecomunicaciones (E3T) yde Ingeniería Metalúrgica y Ciencia de Materiales (EIMCM), están desarrollando actualmenteun proyecto para la construcción de equipos UIS, que permitan realizar actividades delaboratorios y de investigación que puedan ser revisados y reparados in situ. Elpresente artículoexpone el proceso seguido para el diseño y construcción de un primer prototipo para serimplementado en el laboratorio de corrosión de la EIMCM, el cual se ha denominado SistemaPotenciostato Galvanostato Autónomo (SPGA). Un Sistema Potenciostato Galvanostato Autónomo se define como un equipo que pennite realizarpruebas electroquímicas con propósitos de valorar la corrosión en un material; ya seasuministrando una diferencia de potencial controlada y sensando la corriente que circula através de una celda electroquímica (modo Potenciostato) o suministrando una corrientecontrolada sensando la diferencia de potencial en las terminales de la celda (modo Galvanostato), registrando en fonna automática los valores a lo largo de la prueba, indicandosituaciones anormales y desactivando el equipo cuando las condiciones así lo requieran, ofreciendoademás la posibilidad de transmitir los datos a un pey generar la visualización de los datos parapermitir hacer observaciones y establecer conclusiones acerca de la prueba. &nbsp

Utilización de muestras de líquido esofagofaringeo para el diagnóstico de fiebre aftosa.

El diagnóstico etiológico de la fiebre aftosa (FA), se hace mediante la tipificación por la tecnica de la fijación del complemento con muestras de epitelio obtenidas de animales enfermos. En el LIMV, se hizo una investigación con el fin de mostrar la utilidad de la técnica de aislamiento de virus a partir de líquido esofágo-faríngeo (LEF) para la recuperación del virus de la fiebre aftosa en brotes de enfermedades vesiculares en los cuales no fue posible obtener muestras adecuadas de epitelios para las pruebas de diagnóstico por la fijación del complemento. Las muestras de LEF se tomaron de animales que se encontraban en la fase de recuperación, después de sufrir la enfermedad vesicular y en lapsos de tiempo variables, hasta 2 meses después de las manifestaciones clínicas. Se obtuvo el aislamiento de virus de FA en las muestras correspondientes de 19 a 32 hatos estudiados. Los virus fueron clasificados como pertenecientes a los tipos A y O de FA. Se investigó la presencia de anticuerpos séricos, contra el antígeno asociado a la infección por virus de la FA en los animales muestreados para aislamiento de virus. Los resultados obtenidos señalan que la técnica empleada para el aislamiento de virus, es una prueba eficiente que podría reforzar la vigilancia epidemiológica de la FA basada en el diagnóstico etiológicoGanado de doble propósito-Ganaderia doble proposit

Las proteínas del plasma seminal incrementan la viabilidad espermática post-descongelación del semen de toros Sanmartinero

RESUMEN Objetivo. El objetivo de este trabajo fue evaluar el efecto de la adición de proteínas del plasma seminal sobre el porcentaje de espermatozoides bovinos viables post-descongelación. Materiales y métodos. Los espermatozoides se congelaron usando dos medios (citrato-fructosa-yema y Bioxcell®) y la obtención de proteínas de plasma seminal de bajo peso molecular se realizó por medio de cromatografía líquida de baja presión. Las proteínas de interés eluyeron en las fracciones 21-25 y se sometieron a electroforésis en una y dos dimensiones. Los espermatozoides se incubaron a 37°C durante una hora, con 0.5, 1.0, 1.5 y 2.0 mg de la fracción 21-25. Se incluyeron dos tratamientos adicionales: uno con proteínas totales del plasma seminal y otro sin proteína. Resultados. La electroforésis bidimensional de las fracciones confirmó la presencia de siete puntos de proteína de bajo peso molecular (14-16 kDa y punto Isoeléctrico de 5.0 - 5.5). La adición de estas proteínas aumentó 20% (p<0.05), el porcentaje de espermatozoides viables post-descongelación en muestras congeladas en medio citrato-fructosa-yema (con dosis de 1 ó 1.5 mg de proteína/106 espermatozoides), y 25% (p<0.05) en muestras congeladas en medio Bioxcell® (con dosis de 0.5 mg de proteína/106 espermatozoides). Conclusiones. Los resultados de esta investigación sugieren el posible uso de proteínas de bajo peso molecular del plasma seminal, para disminuir el efecto deletéreo de la criopreservación en los espermatozoide

Miniatures from domestic contexts in Iron age Iberia

This article reviews a set of miniatures from domestic contexts in Iron Age eastern Iberia, and interprets them in terms of their role in forging social personae. After an introduction to the historical case under consideration, the miniatures are described in terms of their typology and their contexts of provenance are outlined. Though not abundant, they tend to occur in central places in the landscape; specifically, they are often found in houses of the powerful. The vast majority are miniatures of pottery and tools, though some miniature weapons are recorded. We contend that these objects were used as a means of enculturation and for the learning of values and norms. It is no coincidence that they emerge in the archaeological record of Iron Age Iberia at the same time as the rise of a social structure based on hereditary power

Double blind, randomized, placebo controlled clinical trial for the treatment of diabetic foot ulcers, using a nitric oxide releasing patch: PATHON

<p>Abstract</p> <p>Background</p> <p>Diabetes Mellitus constitutes one of the most important public health problems due to its high prevalence and enormous social and economic consequences. Diabetic foot ulcers are one of the chronic complications of diabetes mellitus and constitute the most important cause of non-traumatic amputation of inferior limbs. It is estimated that 15% of the diabetic population will develop an ulcer sometime in their lives. Although novel therapies have been proposed, there is no effective treatment for this pathology. Naturally produced nitric oxide participates in the wound healing process by stimulating the synthesis of collagen, triggering the release of chemotactic cytokines, increasing blood vessels permeability, promoting angiogenic activity, stimulating the release of epidermical growth factors, and by interfering with the bacterial mitochondrial respiratory chain. Topically administered nitric oxide has demonstrated to be effective and safe for the treatment of chronic ulcers secondary to cutaneous leishmaniasis. However, due to their unstable nitric oxide release, the topical donors needed to be applied frequently, diminishing the adherence to the treatment. This difficulty has led to the development of a multilayer polymeric transdermal patch produced by electrospinning technique that guarantees a constant nitric oxide release. The main objective of this study is to evaluate the effectiveness and safety of this novel nitric oxide releasing wound dressing for the treatment of diabetic foot ulcers.</p> <p>Methods and design</p> <p>A double-blind, placebo-controlled clinical trial, including 100 diabetic patients was designed. At the time of enrollment, a complete medical evaluation and laboratory tests will be performed, and those patients who meet the inclusion criteria randomly assigned to one of two groups. Over the course of 90 days group 1 will receive active patches and group 2 placebo patches. The patients will be seen by the research group at least every two weeks until the healing of the ulcer or the end of the treatment. During each visit the healing process of the ulcer, the patient's health status and the presence of adverse events will be assessed. Should the effectiveness of the patches be demonstrated an alternative treatment would then be available to patients.</p> <p>Trial registration</p> <p>NCT00428727.</p

Regulatory sites for splicing in human basal ganglia are enriched for disease-relevant information

Genome-wide association studies have generated an increasing number of common genetic variants associated with neurological and psychiatric disease risk. An improved understanding of the genetic control of gene expression in human brain is vital considering this is the likely modus operandum for many causal variants. However, human brain sampling complexities limit the explanatory power of brain-related expression quantitative trait loci (eQTL) and allele-specific expression (ASE) signals. We address this, using paired genomic and transcriptomic data from putamen and substantia nigra from 117 human brains, interrogating regulation at different RNA processing stages and uncovering novel transcripts. We identify disease-relevant regulatory loci, find that splicing eQTLs are enriched for regulatory information of neuron-specific genes, that ASEs provide cell-specific regulatory information with evidence for cellular specificity, and that incomplete annotation of the brain transcriptome limits interpretation of risk loci for neuropsychiatric disease. This resource of regulatory data is accessible through our web server, http://braineacv2.inf.um.es/