2,363 research outputs found
Laccase/TEMPO-mediated bacterial cellulose functionalization: production of paper-silver nanoparticles composite with antimicrobial activity
“This is a post-peer-review, pre-copyedit version of an article published in Cellulose. The final authenticated version is available online at: https://doi.org/10.1007/s10570-019-02678-5Bacterial cellulose (BC) was functionalized applying the Laccase/TEMPO oxidative treatment, leading to a five-fold increase of the concentration of carboxyl groups. Paper produced with this cellulose showed improved mechanical properties while maintaining barrier function against water and greases as compared to paper produced with non-oxidized BC. Also, the negative charge provided by the carboxyl groups on functionalized BC was used to generate silver nanoparticles (AgNPs), obtaining a BC paper and Ag composite. The presence of AgNPs in the composites was validated by SEM, EDS and ICP analysis, showing spherical, uniformly sized particles stabilized in the BC nanofibers matrix. Additionally, antimicrobial property of composites containing AgNPs was tested. The results showed the strong antimicrobial activity of the composites against Gram-positive and Gram-negative bacteria and fungi. The generation of Ag nanoparticles in a matrix that combine the physical characteristics of the BC nanofibers with the stiffness and the mechanical properties of paper produced composites that may have applicability in technological and biomedical usesPeer ReviewedPostprint (author's final draft
Heterogeneous pipelined square-root Kalman Filter algorithm for the MMSE-OSIC problem
The final publication is available at Springer via http://dx.doi.org/10.1007/s11227-009-0354-x[EN] This paper describes a pipelined parallel algorithm for the MMSE-OSIC decoding procedure proposed in V-BLAST wireless MIMO systems, for heterogeneous networks of processors. It is based on a block version of the square-root Kalman Filter algorithm that was initially devised to solve the RLS problem. It has been parallelized in a pipelined way obtaining a good efficiency and scalability. The optimum load balancing for this parallel algorithm is dynamic, but we derive a static load balancing scheme with good performance. © 2009 Springer Science+Business Media, LLC.This work has been supported by the Generalitat Valenciana, project 20080811, by the Universidad Politecnica de Valencia, project 20080009, by the Conserjería de Educacion de la Región de Murcia (Fundacion Séneca, 08763/PI/08), and by the Ministerio de Ciencia e Innovacion (TIN2008-06570-C04-02).Martínez Zaldívar, FJ.; Vidal Maciá, AM.; Giménez Cánovas, D. (2011). Heterogeneous pipelined square-root Kalman Filter algorithm for the MMSE-OSIC problem. Journal of Supercomputing. 58(2):235-243. https://doi.org/10.1007/s11227-009-0354-xS235243582Foschini GJ (1996) Layered space-time architecture for wireless communications in a fading environment when using multiple antennas. Bell Labs Techn J 1:41–59Hassibi B (2000) An efficient square-root algorithm for BLAST. In: IEEE international conference on acoustics, speech and signal processing 2000, vol 2, pp II737–II740Zhu H, Lei Z, Chin FPS (2004) An improved square-root algorithm for BLAST. IEEE Signal Process Lett 11(9)Choi Y-S, Voltz PJ, Cassara FA (2001) On channel estimation and detection for multicarrier signals in fast and selective Rayleigh fading channels. IEEE Trans Commun 49(8)Burg A, Haene S, Perels D, Luethi P, Felber N, Fichtner W (2006) Algorithm and VLSI architecture for linear MMSE detection in MIMO-OFDM systems. In: Proceedings of the IEEE int symp on circuits and systems, May 2006Martínez Zaldívar FJ (2007) Algoritmos paralelos segmentados para los problemas de Mínimos Cuadrados Recursivos (RLS) y de Detección por Cancelación Ordenada y Sucesiva de Interferencia (OSIC). PhD thesis, Facultad de Informática, Universidad Politécnica de Valencia, SpainSayed AH, Kailath T (1994) A state-space approach to adaptive RLS filtering. IEEE Signal Process Mag 11(3):18–60Kumar V, Gram A, Gupta A, Karypis G (2003) An introduction to parallel computing: design and analysis of algorithms, Chap 4, 2nd edn. Addison-Wesley, Harlow
Fijacion de nitrogeno por algas cianoficeas en los arrozales de la Albufera de Valencia
Se realizan recuentos ,aislamiento, identificación y determinación de la actividad Nitrogenasa de algas azules en muestras de suelo y agua, durante dos ciclos de cultivo del arroz . Los recuentos se realizan por la técnica del 'Plate Count', utilizando el medio de Chu y los resultados muestran grandes fluctuaciones en las muestras de agua, manteniéndose más altos y uniformes en las muestras de suelo. Después del aislamiento e identificación, llegamos a obtener colonias algales correspondientes en su mayor parte a los géneros Anabaena y Nostoc, las cuales se someten posteriormente a ensayos de reducción del acetileno, para determinar su actividad fijadora de nitrógeno. La especie identificada como N. humifusum, es en nuestras condiciones, la que posee mayor actividad fijadora, además de ser la más común en los dos campos de arroz ensayados
Análisis estructural y evolución tectonometamórfica del basamento de las cuencas neógenas de Vera y Huercal-Overa, Béticas orientales
The basement of the Vera and Huercal Overa basins (southeastem Betics) is fonned by
rocks ofthe Alboran Crustal Domain; a terrain which collided with the South-Iberian and Maghrebian
continentalmargins in the Lower Miocene, resulting in the fonnation of the Gibraltar Are mountain
chain. The Alpuja1Tide complex which occupies an intermediate structural position within the Alboran
Domain, above the Nevado-Filabride and below the Malaguide complexes, includes at least three
tectonic units in the southeastern Betics. From bottom to top in the slTuctural sequence, these units
are Almagro, Almanzora and Variegato. The metapelitic rocks of these units show significative
differences in their tectonic fabrics and in their P-T metamorphic paths. The lower Almagro unit
underwent low-P/low-T metamorphism (300 oc and 3-4 kbar) and its metapelites are slates with no
differentiated metamorphic fabric, which show two sets of spaced axial-plane cleavages. The
intennediate Almanzora unit has two differentiated metamorphic fabrics. The oldest foliation (S,)
preserved in quartz-rich domains of a crenulation cleavage (S ce) grew during high-P/low-T
metamorphism (between 300 °C/12 kbar and 350 oC/6 kbar). The Scc cleavage deyeloped after an
isobaric heating to 475 oc at 5 kbar and registers an initial isothennal decompression to 475 oc at 3
kbar followed by cooling to 300 oc at 2 kbar. A brittle spaced cleavage axial plane to N-vergent
asymmetric folM cuts the S ce fabtic.
At the top ofthe Alpujarride tectonic pile the Variegato unit, includes up to tlu·ee imbrications formed
from top to bottom by gamet schists, fine"grained schists and Triassic carbonates. The main Scc foliation
in the gamet schists grew during a nearly isothennal decompression between 500 oc at 8 kbar and 525 oc at 2 kbar. In the Variegato dark schists, the spaced crenulation cleavage associated to Nvergent
folds is defined by muscovite and chlorite lepidoblasts and is overprinted by the growth of
andalousite porphyroblasts. This assemblage equilibrated at 450-460 oc at 2 kbar.
The Variegato fine-grained schists include a high-P/low-T Mg-carpholite-bearing assemblage, within
pre-Scc quartz veins equilibrated at 8-10 kbar and approximately 400 °C. Furthermore, a chlorite +
phengite + quartz assemblage defining the se relic foliation in lenticular domains of the scc cleavage
shows local equilibria at 11 to 9 kbar at 400 °C.
The superposition ofthese units was related with N-directed compressional brittle-ductile shear zones
and associated N-vergent asymmetric folds, which were active at a late stage of the metamorphic
evolution after coaxial ductile flattening of the Variegato and Almanzora units. The thrust pile that
resulted from this late compressional event was later thinned by two consecutive brittle extensional
systems with northward and southwestward tectonic transport. Final! y, these metamorphic rocks were
exhumed to the surface in the core of E-W oriented anticlinal ridges, which developed during the
Upper Neogene and the Quaternary. Folding and strike-slip faulting of the Miocene Alboran basin
produced the present basin and range morphology of the southeastern Betics, which is characterised
by the formation of isolated sedimentary basins in the synclines
Radon and material radiopurity assessment for the NEXT double beta decay experiment
The Neutrino Experiment with a Xenon TPC (NEXT), intended to investigate the
neutrinoless double beta decay using a high-pressure xenon gas TPC filled with
Xe enriched in 136Xe at the Canfranc Underground Laboratory in Spain, requires
ultra-low background conditions demanding an exhaustive control of material
radiopurity and environmental radon levels. An extensive material screening
process is underway for several years based mainly on gamma-ray spectroscopy
using ultra-low background germanium detectors in Canfranc but also on mass
spectrometry techniques like GDMS and ICPMS. Components from shielding,
pressure vessel, electroluminescence and high voltage elements and energy and
tracking readout planes have been analyzed, helping in the final design of the
experiment and in the construction of the background model. The latest
measurements carried out will be presented and the implication on NEXT of their
results will be discussed. The commissioning of the NEW detector, as a first
step towards NEXT, has started in Canfranc; in-situ measurements of airborne
radon levels were taken there to optimize the system for radon mitigation and
will be shown too.Comment: Proceedings of the Low Radioactivity Techniques 2015 workshop
(LRT2015), Seattle, March 201
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