Superficial Surface Treatment using Atmospheric Plasma on Recycled Nylon 6,6

Polymers currently represent materials that are cost-effective, while its recycled nature is significant in terms of environmental protection. However, the surface properties of polymers often do not meet the demands of wettability, adhesion, and friction, among others. Atmospheric plasma treatment on the surface of polymers improves its physical-chemistry properties. In this work, a recycled nylon coating was prepared by the spin coating technique and characterized by Fourier transform infrared spectroscopy and X-ray diffraction. This coating was treated by atmospheric plasma, and Raman spectroscopy was performed to analyze the signals related to different functional groups present in the coating surface after plasma treatment. The action of plasma on the surface morphology was observed by scanning electron microscopy. The contact angle results showed an improvement in surface wettability

Estimación de propiedades del suelo a partir de espectroscopía de infrarrojo medio

La técnica de infrarrojo medio (MIR) puede ser utilizada para identificar y para estimar las propiedades de suelos, con gran precisión. El objetivo del presente estudio fue evaluar el potencial de la espectroscopia de reflectancia en el infrarrojo medio (MIR), para la estimación de algunas propiedades químicas del suelo, así como la aplicación de esta técnica, en la obtención de mapas digitales. Fueron analizadas 249 muestras de suelos de dos órdenes, correspondiente a Andisoles y Oxisoles. Los resultados obtenidos en el análisis de las curvas permiten verificar que el mayor número de atributos están reflejados en la región espectral de 400 y 850cm-1. El Andisol, se destacó por obtener mejores resultados en la calibración de los modelos que el Oxisol. Las respuestas espectrales en ambos suelos fueron similares, pero con diferentes niveles de reflectancia. Esta diferencia fue más marcada en los Andisoles, donde los picos espectrales fueron más bajos, hecho atribuible a los compuestos de la materia orgánica que tienden a oscurecer el suelo absorbiendo la luz infrarroja. Los resultados demuestran que la espectroscopia de reflectancia infrarroja MIR permite procesar una gran cantidad de muestras, donde se obtiene información sobre varios parámetros en un solo espectro. El carbono orgánico fue el atributo con la mejor predicción. De igual manera, los modelos de semivariograma, como los mapas de contorno, obtenidos a partir de los modelos con datos espectrales, mostraron alta similitud con los obtenidos a partir de las mediciones hechas en laboratorio, para aquellas propiedades, donde los modelos espectrales fueron representativos.The mid-infrared technique (MIR) can be used to identify and estimate soil properties with high accuracy. The aim of this study was to evaluate the potential of mid-infrared reflectance spectroscopy (MIR) for the estimation of chemical properties of soils as well as the application of this technique in obtaining digital maps. In this study, 249 soil samples from two orders, Andisols and Oxisols, were analyzed. The results obtained in the analysis of the curves verified that the greater number of attributes was reflected in the spectral region of 400 and 850cm-1. The Andisols stood out due to the results in the calibration of the models, which were better than those of the Oxisols. The spectral responses were similar in both soils, but with different levels of reflectivity. This difference was more notable in the Andisols, where the spectral peaks were lower, a fact attributable to the compounds of the organic matter that tended to obscure the soil, absorbing infrared light. The results demonstrated that the mid-infrared reflectance spectroscopy MIR allowed for the processing of a large number of samples, where information about various parameters was obtained in a single spectrum. The organic carbon was the attribute with the best prediction. Similarly, the semivariogram models and contour maps obtained from the spectral data models showed high similarity to those obtained from the laboratory measurements for those properties, where the spectral models were representative.Incluye referencias bibliográfic

Visual and poetic narratives of the city

Ensayo que intenta, de un lado, contribuir al esclarecimiento de la crisis visual y poética de las ciudades. La tesis inicialmente propuesta se ha modificado ligeramente: el acceso del transeúnte y del espectador a los “textos visuales” de la ciudad, constituye una experiencia fragmentaria que se relaciona en una ocasión con el reconocimiento narrativo de ciertos trozos o trazas de ciudad, y, de otro lado, un irreconocimiento “esquizosémico”, una función de desconocimiento y de pérdida o de extravío que surge de la experiencia de la urbe suprematista, funcionalista, minimalista. De otro lado, las consecuencias que derivan del establecimiento de una geografía del Kitsch, y de la expansión de este fenómeno sociocultural, los presupuestos analíticos en el reconocimiento de la ciudad como Kitsch en las retóricas y poéticas visuales.Abstract This essay attempts, firstly, to help clarify the visual and poetic crisis of the cities. The initial thesis proposed has been slightly modified: the passer-by’s and the viewer’s access to “visual texts” of the city, makes up a fragmentary experience that relates, on one occasion, with the narrative acknowledgement of certain fragments or traces of the city; and, on the other hand, a “schizosemic” unacknowledgement, an ignorance and loss function arising from the experience of the suprematist, functionalist and minimalist city. Moreover, the consequences derived from the establishment of a Kitsch geography, and from the expansion of this socio-cultural phenomenon, the analytical assumptions in the recognition of the city as Kitsch in visual rhetoric and poetics

Narrativas visuales y poéticas de ciudad

Ensayo que intenta, de un lado, contribuir al esclarecimiento de la crisis visual y poética de las ciudades. La tesis inicialmente propuesta se ha modificado ligeramente: el acceso del transeúnte y del espectador a los “textos visuales” de la ciudad, constituye una experiencia fragmentaria que se relaciona en una ocasión con el reconocimiento narrativo de ciertos trozos o trazas de ciudad, y, de otro lado, un irreconocimiento “esquizosémico”, una función de desconocimiento y de pérdida o de extravío que surge de la experiencia de la urbe suprematista, funcionalista, minimalista. De otro lado, las consecuencias que derivan del establecimiento de una geografía del Kitsch, y de la expansión de este fenómeno sociocultural, los presupuestos analíticos en el reconocimiento de la ciudad como Kitsch en las retóricas y poéticas visuales

BRAF and TERT mutations in papillary thyroid cancer patients of Latino ancestry.

Papillary thyroid cancer (PTC) is the second most commonly diagnosed malignancy in U.S. Latinas and in Colombian women. Studies in non-Latinos indicate that BRAF and TERT mutations are PTC prognostic markers. This study aimed to determine the prevalence and clinical associations of BRAF and TERT mutations in PTC Latino patients from Colombia. We analyzed mutations of BRAF (V600E) and TERT promoter (C228T, C250T) in tumor DNA from 141 patients (75 with classical variant PTC, CVPTC; 66 with follicular variant PTC, FVPTC) recruited through a multi-center study. Associations between mutations and clinical variables were evaluated with Fisher exact tests. Survival was evaluated with Kaplan-Meier plots. Double-mutant tumors (BRAF+/TERT+, n = 14 patients) were more common in CVPTC (P = 0.02). Relative to patients without mutations (n = 48), double mutations were more common in patients with large tumors (P = 0.03), lymph node metastasis (P = 0.01), extra-thyroid extension (P = 0.03), and advanced stage (P = 6.0 × 10-5). In older patients, TERT mutations were more frequent (mean age 51 years vs 45 years for wild type TERT, P = 0.04) and survival was lower (HR = 1.20; P = 0.017); however, given the small sample size, the decrease in survival was not statically significant between genotypes. Comparisons with published data in US whites revealed that Colombian patients had a higher prevalence of severe pathological features and of double-mutant tumors (10 vs 6%, P = 0.001). Mutations in both oncogenes show prognostic associations in Latinos from Colombia. Our study is important to advance Latino PTC precision medicine and replicates previous prognostic associations between BRAF and TERT in this population

Growth of the tropical scallop, Euvola (Pecten) ziczac, in bottom and suspended culture in the Golfo de Cariaco, Venezuela

We compared the growth of the scallop Euuolu (Pecten) ziczuc (L.) in three situations which potentially could be used for commercial culture, in cages maintained in suspension, in cages on the bottom and in cages partly buried in a sediment bottom. The latter permitted the scallops to bury themselves as in their natural habitat. Throughout the 7-month study, growth, as measured by shell length and muscle mass, was by far superior for scallops in the partly buried cages. Possible explanations for this are ( 1) that the scallops are stressed by enclosures which prevent them from burying themselves and (2) that organic material at the sediment/water interface is an important food resource and E. ziczac has better access to this when it buries itself flush with the bottom. The timing of gonadal growth and spawning varied markedly among treatments. Some spawnings coincided with temperature increases but others did not. Differences between scallops in suspension compared to those in bottom treatments suggested that reproduction is as much controlled by conditions in the immediate environment of the scallops as by large-scale environmental factors. Survival was highest for the scallops maintained in partly buried cages

Crossed-ratchet effects and domain wall geometrical pinning

The motion of a domain wall in a two dimensional medium is studied taking into account the internal elastic degrees of freedom of the wall and geometrical pinning produced both by holes and sample boundaries. This study is used to analyze the geometrical conditions needed for optimizing crossed ratchet effects in periodic rectangular arrays of asymmetric holes, recently observed experimentally in patterned ferromagnetic films. Geometrical calculations and numerical simulations have been used to obtain the anisotropic critical fields for depinning flat and kinked walls in rectangular arrays of triangles. The aim is to show with a generic elastic model for interfaces how to build a rectifier able to display crossed ratchet effects or effective potential landscapes for controlling the motion of interfaces or invasion fronts.Comment: 13 pages, 18 figure

Una especie nueva de Paratrigona (Hymenoptera: Apidae, Meliponini), con una sinopsis del género en Colombia

Se describe Paratrigona uwa sp. nov., especie aparentemente endémica de la cordillera Oriental de Colombia. También se presentan registros geográficos nuevos y una sinopsis de las 10 especies de Paratrigona que se encuentran en Colombia. No se encontraron especímenes de P. impuntacta y P. ornaticeps en las colecciones más importantes de Colombia; por lo tanto, es posible que los registros de estas especies para el país sean de especímenes mal identificados

Critical Comparison between Modified Monier-Williams and Electrochemical Methods to Determine Sulfite in Aqueous Solutions

In the present work, known concentration of sulfite aqueous solutions in the presence and absence of gallic acid was measured to corroborate the validity of modified Monier-Williams method. Free and bound-sulfite was estimated by differential pulse voltammetry. To our surprise, the modified Monier-Williams method (also known as aspiration method) showed to be very inaccurate for free-sulfite, although suitable for bound-sulfite determination. The differential pulse approach, using the standard addition method and a correction coefficient, proved to be swift, cheap, and very precise and accurate