1,269 research outputs found
Covalent Grafting of Coordination Polymers on Surfaces: The Case of Hybrid Valence Tautomeric Interphases
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. We have developed a novel approach for grafting coordination polymers, structured as nanoparticles bearing surface reactive carboxylic groups, to amino-functionalized surfaces through a simple carbodiimide-mediated coupling reaction. As a proof-of-concept to validate our approach, and on the quest for novel hybrid interphases with potential technological applications, we have used valence tautomeric nanoparticles exhibiting spin transition at or around room temperature. SEM and AFM characterization reveal that the nanoparticles were organized chiefly into a single monolayer while X-ray photoelectron spectroscopy (XPS) measurements confirm that the nanoparticles retain a temperature-induced electronic redistribution upon surface anchorage. Our results represent an effective approach towards the challenging manufacture of coordination polymers. CPPs immobilization: A generic approach for immobilizing coordination polymer nanoparticles (CPPs) on gold surfaces is reported. The protocol involves covalent bonding between amino-terminated alkyl chains on the gold surface and carboxylic groups on the CPPs surface. The thickness of the nanoparticle monolayer is comparable to the nanoparticle size. The nanoparticles used exhibit valence tautomerism in bulk and keep this property after surface attachment, as corroborated by X-ray photoelectron spectroscopy (XPS) measurements. The results represent an effective approach towards the manufacture of coordination polymers.F. N. thanks the Ministerio de Ciencia e Innovación (MICINN) for a postdoctoral JdC fellowship. This work was supported by project MAT2012-38318-C03-02 from the Spanish Government and by FEDER funds. ICN2 acknowledges support from the Severo Ochoa Program (MINECO, Grant SEV-2013-0295). The authors also thank MP1202 Cost ActionPeer Reviewe
Quantitative phase determination by using a Michelson interferometer
The Michelson interferometer is one of the best established tools for quantitative interferometric measurements. It has been, and is still successfully used, not only for scientific purposes, but it is also introduced in undergraduate courses for qualitative demonstrations as well as for quantitative determination of several properties such as refractive index, wavelength, optical thickness, etc. Generally speaking, most of the measurements are carried out by determining phase distortions through the changes in the location and/or shape of the interference fringes. However, the extreme sensitivity of this tool, for which minimum deviations of the conditions of its branches can cause very large modifications in the fringe pattern, makes phase changes difficult to follow and measure. The purpose of this communication is to show that, under certain conditions, the sensitivity of the Michelson interferometer can be 'turned down' allowing the quantitative measurement of phase changes with relative ease. As an example we present how the angle (or, optionally, the refractive index) of a transparent standard optical wedge can be determined. Experimental results are shown and compared with the data provided by the manufacturer showing very good agreement.Fil: Pomarico, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: Molina, Pablo Fernando. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: D'angelo, Cristian Adrián. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; Argentin
Tackling the Peak Overlap Issue in NMR Metabolomics Studies: 1D Projected Correlation Traces from Statistical Correlation Analysis on Nontilted 2D 1 H NMR J-Resolved Spectra
The identification of metabolites in complex biological matrices is a challenging task in 1D 1 H-NMR-based metabolomics studies. Statistical total correlation spectroscopy (STOCSY) has emerged for aiding the structural elucidation by revealing the peaks that present a high correlation to a driver peak of interest (which would likely belong to the same molecule). However, in these studies, the signals from metabolites are normally present as a mixture of overlapping resonances, limiting the performance of STOCSY. As an alternative to avoid the overlap issue, 2D 1 H homonuclear J-resolved (JRES) spectra were projected, in their usual tilted and symmetrized processed form, and STOCSY was applied on these 1D projections (p-JRES-STOCSY). Nonetheless, this approach suffers in cases where the signals are very close. In addition, STOCSY was applied to the whole JRES spectra (also tilted) to identify correlated multiplets, although the overlap issue in itself was not addressed directly and the subsequent search in databases is complicated in cases of higher order coupling. With these limitations in mind, in the present work, we propose a new methodology based on the application of STOCSY on a set of nontilted JRES spectra, detecting peaks that would overlap in 1D spectra of the same sample set. Correlation comparison analysis for peak overlap detection (COCOA-POD) is able to reconstruct projected 1D STOCSY traces that result in more suitable database queries, as all peaks are summed at their f2 resonances instead of the resonance corresponding to the multiplet center in the tilted JRES spectra. (The peak dispersion and resolution enhancement gained are not sacrificed by the projection.) Besides improving database queries with better peak lists obtained from the projections of the 2D STOCSY analysis, the overlap region is examined, and the multiplet itself is analyzed from the correlation trace at 45° to obtain a cleaner multiplet profile, free from contributions from uncorrelated neighboring peaks.Fil: Charris Molina, Andres Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Riquelme, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Burdisso, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Hoijemberg, Pablo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentin
Transcriptional regulation of genes involved in the symbiosis between Nostoc and Oryza
Motivation: Cyanobacteria of the genus Nostoc are capable of establishing symbiosis relationships with many different types of plants. In these mutualistic relationships the cyanobacterium provides the plant with fixed nitrogen, while the plant provides the cyanobacterium with protection from hostile environments and carbon compounds as energy for N2 fixation. It has recently been described that Nostoc punctiforme performs a stable symbiosis with Oryza sativa (Álvarez et al., 2020). In order to know the molecular mechanisms involved in the recognition between the plant and the cyanobacterium, a proteomic study was carried out in the early stages of co-culture of both organisms. In this study, proteins with homology to the Nod factors of Rhizobium sp. were identified in Nostoc, which could be related to signaling in the plant. The aim of this work is to study the regulation of the expression of the genes encoding these Nod proteins by means of RT-qPCR.
Methods: The expression of Nostoc punctiforme Nod genes was studied in response to the presence of the plant at 1, 2, 3, 5 and 7 days of co-culture. On the one hand, a Nostoc punctiforme culture grown at 25°C in Roux flasks with 1% CO2, continuous illumination and at 30°C was prepared. On the other hand, Oryza sativa seedlings were obtained germination of seeds under axenic conditions. At one week of growth, the seedlings were transplanted into flasks with hydroponic medium. Co-culture was performed by adding a fixed amount of Nostoc to the Oryza culture medium, and incubating the mixture in thermostated chambers at 25°C, 12h light/dark cycles and 75% relative humidity. RNA was extracted from Nostoc samples that had been in contact with the plant. As a control, Nostoc incubated without the plant was used. After RNA retrotranscription, the resulting cDNA was used to evaluate the expression of the genes of interest.
Results: It was observed that the expression of certain Nod genes is activated in the presence of Oryza, although there are other Nod genes whose expression remains unchanged in response to inoculation with the plant
A Topologically Consistent Color Digital Image Representation by a Single Tree
A novel, flexible (non-unique) and topologically consistent
representation called CRIT (Contour-Region incidence Tree) for a color
2D digital image I is defined here. The CRIT is a tree containing all the
inter and intra connectivity information of the constant-color regions.
Considering I as an abstract cell complex (ACC), its topological infor mation can be packed as a smaller (in terms of cells) ACC, whose 2-cells
are the different constant-color regions of I. This modus operandi over comes the classical connectivity paradoxes of digital images by working
with lower-dimensional cells such as 0-cells, 1-cells, and 2-cells. The CRIT
structure allows to describe this smaller ACC in a non-redundant way.
The proposed technique is based on the previous construction of the
Homological Spanning Forest (HSF) structures for encoding homological
information of the ACCs canonically associated to I, in terms of rooted
trees connecting digital object elements without redundancyMinisterio de Ciencia e Innovación PID2019-110455GB-I00 (Par-HoT
Vivencias de malestar derivados de las lecciones no aprendidas en el contexto del trabajo organizado
Objetivo: caracterizar las vivencias de malestar experimentadas por un grupo de trabajadores derivadas de las lecciones no aprendidas en la pandemia en el contexto del trabajo organizado. Método: es un estudio descriptivo, análisis cualitativo con diseño narrativo y transversal. Resultados: las lecciones organizacionales no aprendidas causantes de malestar y sufrimiento tienen un impacto en los sujetos con una intensidad subjetiva. En términos generales a las organizaciones les faltó y a muchas aún les falta establecer procesos en los que se refuercen actividades de reconocimiento que interrumpan la tendencia que las convierte en generadoras de malestar y sufrimiento. Conclusión: se evidencia que las experiencias de malestar y sufrimiento relacionadas a la manera como las organizaciones gestionan los cambios que trajo la pandemia por Covid-19 son reales, como la inflexibilidad horaria, la falta de escucha activa, la sobrecarga laboral, la ausencia de reconocimiento que algunas organizaciones y las personas que las conforman tienen la intención de actuar bien en algunos aspectos importantes, pero son culturalmente resistentes a la nueva realidad
Parallel Image Processing Using a Pure Topological Framework
Image processing is a fundamental operation
in many real time applications, where lots of parallelism
can be extracted. Segmenting the image into different
connected components is the most known operations, but
there are many others like extracting the region adjacency
graph (RAG) of these regions, or searching for features
points, being invariant to rotations, scales, brilliant
changes, etc. Most of these algorithms part from the basis
of Tracing-type approaches or scan/raster methods. This
fact necessarily implies a data dependence between the
processing of one pixel and the previous one, which
prevents using a pure parallel approach. In terms of time
complexity, this means that linear order O(N) (N being the
number of pixels) cannot be cut down. In this paper, we
describe a novel approach based on the building of a pure
Topological framework, which allows to implement fully
parallel algorithms. Concerning topological analysis, a first
stage is computed in parallel for every pixel, thus
conveying the local neighboring conditions. Then, they are
extended in a second parallel stage to the necessary global
relations (e.g. to join all the pixels of a connected
component). This combinatorial optimization process can
be seen as the compression of the whole image to just one
pixel. Using this final representation, every region can be
related with the rest, which yields to pure topological
construction of other image operations. Besides, complex
data structures can be avoided: all the processing can be
done using matrixes (with the same indexation as the
original image) and element-wise operations. The time
complexity order of our topological approach for a m×n
pixel image is near O(log(m+n)), under the assumption that
a processing element exists for each pixel. Results for a
multicore processor show very good scalability until the
memory bandwidth bottleneck is reached, both for bigger
images and for much optimized implementations. The
inherent parallelism of our approach points to the
direction that even better results will be obtained in other
less classical computing architectures.1Ministerio de Economía y Competitividad (España) TEC2012-37868-C04-02AEI/FEDER (UE) MTM2016-81030-PVPPI of the University of Sevill
Implementación del área de coordinación de diseños técnicos de los proyectos de construcción de la promotora Vivendum S.A.
La implementación del área de coordinación de diseños técnicos dentro de la Promotora Vivendum S.A. marca un antes y un después dentro de la organización, toda vez que esto permite una gestión adecuada de los recursos financieros, humanos e insumos disponibles a fin de poder optimizar la realización de actividades y uso de los recursos al disponer de esta área que funciona como el cerebro de las operaciones en la compañía. Dentro de este trabajo, se muestra el proceso por medio de la gestión de proyectos del estudio para la puesta en marcha del área que buscará la reducción de los costos directos e indirectos asociados al proyecto de construcción “Picasso” en Tunja.
Es importante aclarar, que dentro de la organización Promotora Vivendum trabajan 47 colaboradores directos, por lo que este proyecto impacta en sus funciones y en la realización de próximos proyectos de construcción dada la facilidad de la realización y coordinación de tareas que el área, desde sus funciones permite realizar
On the Topological Disparity Characterization of Square-Pixel Binary Image Data by a Labeled Bipartite Graph
Given an nD digital image I based on cubical n-xel, to fully
characterize the degree of internal topological dissimilarity existing in I
when using different adjacency relations (mainly, comparing 2n or 2n −1
adjacency relations) is a relevant issue in current problems of digital
image processing relative to shape detection or identification. In this
paper, we design and implement a new self-dual representation for a
binary 2D image I, called {4, 8}-region adjacency forest of I ({4, 8}-RAF,
for short), that allows a thorough analysis of the differences between the
topology of the 4-regions and that of the 8-regions of I. This model can
be straightforwardly obtained from the classical region adjacency tree
of I and its binary complement image Ic, by a suitable region label
identification. With these two labeled rooted trees, it is possible: (a) to
compute Euler number of the set of foreground (resp. background) pixels
with regard to 4-adjacency or 8-adjacency; (b) to identify new local and
global measures and descriptors of topological dissimilarity not only for
one image but also between two or more images. The parallelization of
the algorithms to extract and manipulate these structures is complete,
thus producing efficient and unsophisticated codes with a theoretical
computing time near the logarithm of the width plus the height of an
image. Some toy examples serve to explain the representation and some
experiments with gray real images shows the influence of the topological
dissimilarity when detecting feature regions, like those returned by the
MSER (maximally stable extremal regions) method.Ministerio de Economía, Industria y Competitividad PID2019-110455GB-I00 (Par-HoT)Junta de Andalucía US-138107
- …