Keratin protein-catalyzed nitroaldol (Henry) reaction and comparison with other biopolymers

Here we describe a preliminary investigation on the ability of natural keratin to catalyze the nitroaldol (Henry) reaction between aldehydes and nitroalkanes. Both aromatic and heteroaromatic aldehydes bearing strong or moderate electron-withdrawing groups were converted into the corresponding -nitroalcohol products in both DMSO and in water in the presence of tetrabutylammonium bromide (TBAB) as a phase transfer catalyst. Negligible background reactions (i.e., negative control experiment in the absence of keratin protein) were observed in these solvent systems. Aromatic aldehydes bearing electron-donating groups and aliphatic aldehydes showed poor or no conversion, respectively. In general, the reactions in water/TBAB required twice the amount of time than in DMSO to achieve similar conversions. Moreover, comparison of the kinetics of the keratin-mediated nitroaldol (Henry) reaction with other biopolymers revealed slower rates for the former and the possibility of fine-tuning the kinetics by appropriate selection of the biopolymer and solvent

Calcium transfer and mass balance associated with soil carbonate in a semi‐arid silicate watershed (North Cameroon): an overlooked geochemical cascade?

International audienceCalcium is a key element of the Earth system and closely coupled to the carbon cycle. Weathering of silicate releases Ca, which is exported and sequestered in oceans. However, pedogenic calcium carbonate constitutes a second Ca-trapping pathway that has received less attention. Large accumulations of pedogenic calcium carbonate nodules, associated with palaeo-Vertisols, are widespread in North Cameroon, despite a carbonate-free watershed. A previous study suggested that a significant proportion of Ca released during weathering was trapped in palaeo-Vertisols but the pathways involved in the transfer of Ca from sources (the granite and the Saharan dust) to a temporary sink (the carbonate nodules) remain unclear. This study aims to compare the distribution of elements in carbonate nodules and their associated past and present compartments for Ca in the landscape. These compartments are all characterised by a distinctive geochemical composition, resulting from specific processes. Three end members have been defined based on geochemical data: (a) the granite and its residual products, dominated by K2O and Na2O, Ti and Zr, HREE, and a positive Ce anomaly; (b) the soil parental material and the Saharan dust, dominated by Al2O3, Fe2O3 and MgO, V, HREE, and a positive Ce anomaly; and finally (c) the carbonate nodules, which are dominated by CaO, a depletion in V, Ti and Zr, and an enrichment in REE with a negative Ce anomaly. Mass balance calculations in soil profiles demonstrated that the accumulation of Ca in carbonate nodules exceeds the Ca released by chemical weathering of the parental material, because of a continuous accumulation and contribution from lateral transfers. Consequently, at the landscape scale, carbonate nodules associated with palaeo-Vertisols constitute a temporary sink for Ca. Such a spatial relationship between sources and transient compartments opens an avenue to the new concept of 'geochemical cascade', similar in terms of geochemistry, to the concept of 'sediment cascade' developed by continental sedimentologists

Objectively Measured Adherence to Physical Activity Guidelines After Acute Coronary Syndrome

Physical activity is a cornerstone of secondary prevention after acute coronary syndromes (ACS). Guidelines strongly recommend that post-ACS patients achieve ≥30 min of moderate aerobic activity such as brisk walking on at least 5 days per week within 2 weeks of discharge (1). Yet, little is known about the extent to which post-ACS patients are meeting physical activity guidelines. Prior studies assessing physical activity after ACS were limited by reliance on self-reports (2). The purpose of this study was to use an objective measure of physical activity to describe the proportion of ACS patients following physical activity recommendations in the high-risk post-discharge period. Between 2009 and 2012, we enrolled patients hospitalized for myocardial infarction (MI) or unstable angina into the PULSE (Prescription Use, Lifestyle, and Stress Evaluation) study. Some patients participated in an ancillary study in which they were provided with an Actical accelerometer (Philips Respironics, Bend, Oregon) at or soon after discharge (3). Patients were asked to continuously wear the device on their nondominant wrist and to return the device 1 month later. All patients provided informed consent. The institutional review board of Columbia University Medical Center approved the study

Evaluation of 3D image-treatment algorithms applied to optical-sectioning microscopy

La información extraída de especimenes biológicos es inherentemente tridimensional. Los datos tridimensionales (3D) permiten un mejor entendimiento de las estructuras y los eventos biológicos, comparados con sus proyecciones bidimensionales (2D), aunque a veces son más difíciles de manejar. Esto explica porqué actualmente se están investigando y mejorando las técnicas de seccionamiento óptico. El principal objetivo del presente trabajo fue evaluar la relevancia de algoritmos de tratamiento de imágenes, los cuales incluyen métodos de preprocesamiento (tales como promediación de imágenes, corrección de background y normalización de intensidades) y procesamiento (desconvolución de desborroneo y de restauración). Esto se realizó mediante la implementación de un algoritmo de cuantificación basado en el Laplaciano y un detector de puntos brillantes. Los algoritmos se aplicaron a un modelo 3D de adhesión celular en piel, basado en un espécimen comúnmente utilizado por nuestro grupo de investigación. Los resultados indican que ciertos métodos de preprocesamiento son requeridos para mejorar el rendimiento de los algoritmos de procesamiento, mientras que otros no deben ser aplicados para asegurar una adecuada y precisa cuantificación.Information extracted from biological specimens is inherently three-dimensional. Though it is sometimes hard to handle, three-dimensional (3D) data provides greater understanding of biological structures and events than its bidimensional (2D) projections. This explains why optical-sectioning techniques are currently being explored and enhanced. The main objective of the present work was to evaluate the relevance of image-treatment algorithms, which included preprocessing (such as image-averaging, background correction and normalization of intensities) and processing (deblurring and restoration deconvolution) methods. This was done by implementing a quantification algorithm based on the Laplacian and a bright-point detector. Algorithms were applied to a 3D cell-adhesion skin model, based upon a specimen commonly used by our research group. Results indicated that certain preprocessing methods are required to enhance the performance of processing algorithms, while others must not be applied in order to ensure an adequate and precise quantification.IV Workshop de Computación Gráfica, Imágenes y Visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI

Process improvement in a virtual organization focused on product development using collaborative environments

Collaborative Engineering Environments (CEE) have become really important in Virtual Organizations (VO) because they enable the coordination and collaboration among engineering groups, supported by tools and methodologies that enable intellectual capital sharing and engineering activities in real time, among organizations regardless of their locations -- A platform that integrates and facilitates the operation in Virtual Organizations focused in manufactured product development, is an important tool that supports a rapid respond to customers, and improve the communication among its members -- This paper present a way to improve business process in a VO based on the development and use of a CEE -- The methodology presented in this paper was implemented in a real manufacturing VO, improving the product transfer process: the coordinators of each business opportunity easily manage VO information, and VO partners were totally involved during the proces

Enhancement of an automatic algorithm for deconvolution and quantification of three-dimensional microscopy images

En trabajos previos hemos diseñado y desarrollado un software para la optimización del procesamiento de imágenes multidimensionales, el cual consiste de un algoritmo automático de desconvolución de restauración (desconvolución con restricción de positividad) y tres indicadores de restauración de la imágenes (Ancho Total a la Mitad del Máximo, Relación Contraste-Ruido y Relación Señal-Ruido) usados para evaluar cuantitativamente la calidad de restauración. Dado que el diseño del algoritmo se implementó en módulos desacoplados, hemos podido incorporar dos nuevos parámetros para evaluar la restauración de imágenes (indicadores tridimensionales basados en la función de Tenegrad) sin realizar cambios significativos en el código. La versión mejorada del algoritmo se utilizó para procesar imágenes tridimensionales utilizando diversas Funciones de Esparcimiento Puntual experimentales; las imágenes se obtuvieron mediante microscopia de campo amplio de fluorescencia del patrón de expresión de E-caderina en la piel de embriones de Rhinella arenarum y de microesferas fluorescentes. Se compararon los indicadores de restauración y el rendimiento de las versiones previa y mejorada del algoritmo. Los resultados indican que los indicadores basados en la función de Tenegrad coinciden con los evaluados previamente y que los nuevos módulos no incrementan significativamente el tiempo de procesamiento.In previous works we designed and developed a software tool for the optimization of multidimensional-image processing, which consisted of an automatic restoration deconvolution method (positive constrained deconvolution) and three image-restoration indicators (Full-Width at Half-Maximum, Contrast-to-Noise Ratio and Signal-to-Noise Ratio) used to assess the quality of restoration qualitatively. Since the algorithm’s design was implemented in uncoupled modules, we were able to introduce two new image-restoration parameters (two three-dimensional Tenegrad-based indicators) without mayor modifications to the script. The enhanced version of the algorithm was used to process raw three-dimensional images using several experimental Point Spread Functions; raw images were obtained by fluorescence wide-field microscopy of epidermal E-cadherin expression in Rhinella arenarum embryos and fluorescent microspheres. The image-restoration indicators and the performance of the previous and enhanced versions of the algorithm were compared. Results show that Tenengrad-based indicators concur with the previously used ones and that the new modules do not increase processing time significantly.Workshop de Computación Gráfica, Imágenes y Visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI