3,529 research outputs found
Dynamical generation of interwoven soliton trains by nonlinear emission in binary Bose-Einstein condensates
We propose a method for the generation of trains of alternating bright
solitons in two-component Bose-Einstein condensates, using controlled emission
of nonlinear matter-waves in the uncoupled regime with spatially-varying
intra-species interaction and out-of-phase oscillations of the ground states in
the trap. Under this scheme, solitons are sequentially launched from the
different components, and interact with each other through phase-independent
cross-coupling. We obtain an analytical estimation of the critical condition
for soliton emission using a geometric guiding model, in analogy with
integrated optical systems. In addition, we show how strong initial
perturbations in the system can trigger the spontaneous generation of
supersolitons, i.e. localized phonon-like excitations of the soliton trains.
Finally, we demonstrate the controllable generation of slow and fast
supersolitons by adding external localized potentials in the nonlinear region
Nanoplastics: From tissue accumulation to cell translocation into Mytilus galloprovincialis hemocytes. resilience of immune cells exposed to nanoplastics and nanoplastics plus Vibrio splendidus combination
Plastic litter is an issue of global concern. In this work Mytilus galloprovincialis was used to study the distribution and effects of polystyrene nanoplastics (PS NPs) of different sizes (50 nm, 100 nm and 1 mu m) on immune cells. Internalization and translocation of NPs to hemolymph were carried out by in vivo experiments, while endocytic routes and effects of PS NPs on hemocytes were studied in vitro. The smallest PS NPs tested were detected in the digestive gland and muscle. A fast and size-dependent translocation of PS NPs to the hemolymph was recorded after 3 h of exposure. The internalization rate of 50 nm PS NPs was lower when caveolae and clathrin endocytosis pathways were inhibited. On the other hand, the internalization of larger particles decreased when phagocytosis was inhibited. The hemocytes exposed to NPs had changes in motility, apoptosis, ROS and phagocytic capacity. However, they showed resilience when were infected with bacteria after PS NP exposure being able to recover their phagocytic capacity although the expression of the antimicrobial peptide Myticin C was reduced. Our findings show for the first time the translocation of PS NPs into hemocytes and how their effects trigger the loss of its functional parameters
Modulational instability windows in the nonlinear Schr\"odinger equation involving higher-order Kerr responses
We introduce a complete analytical and numerical study of the modulational
instability process in a system governed by a canonical nonlinear Schr\"odinger
equation involving local, arbitrary nonlinear responses to the applied field.
In particular, our theory accounts for the recently proposed higher-order Kerr
nonlinearities, providing very simple analytical criteria for the
identification of multiple regimes of stability and instability of plane-wave
solutions in such systems. Moreover, we discuss a new parametric regime in the
higher-order Kerr response which allows for the observation of several,
alternating stability-instability windows defining a yet unexplored instability
landscape.Comment: 9 pages, 8 figure
El licenciado en ciencias de la actividad física y del deporte como readaptador físico-deportivo
LEDGF/p75 TATA-less promoter is driven by the transcription factor Sp1.
PSIP1 (PC4 and SFRS1 interacting protein 1) encodes two splice variants: lens epithelium-derived growth factor or p75 (LEDGF/p75) and p52. PSIP1 gene products were shown to be involved in transcriptional regulation, affecting a plethora of cellular processes, including cell proliferation, cell survival, and stress response. Furthermore, LEDGF/p75 has implications for various diseases and infections, including autoimmunity, leukemia, embryo development, psoriasis, and human immunodeficiency virus integration. Here, we reported the first characterization of the PSIP1 promoter. Using 5' RNA ligase-mediated rapid amplification of cDNA ends, we identified novel transcription start sites in different cell types. Using a luciferase reporter system, we identified regulatory elements controlling the expression of LEDGF/p75 and p52. These include (i) minimal promoters (-112/+59 and +609/+781) that drive the basal expression of LEDGF/p75 and of the shorter splice variant p52, respectively; (ii) a sequence (+319/+397) that may control the ratio of LEDGF/p75 expression to p52 expression; and (iii) a strong enhancer (-320/-207) implicated in the modulation of LEDGF/p75 transcriptional activity. Computational, biochemical, and genetic approaches enabled us to identify the transcription factor Sp1 as a key modulator of the PSIP1 promoter, controlling LEDGF/p75 transcription through two binding sites at -72/-64 and -46/-36. Overall, our results provide initial data concerning LEDGF/p75 promoter regulation, giving new insights to further understand its biological function and opening the door for new therapeutic strategies in which LEDGF/p75 is involved
Aislamiento de cocaína y benzoilecgonina en muestras de orina por extracciones líquido-líquido y en fase sólida y confirmación por Cromatografía líquida de alta resolución (HPLC)
El consumo ilícito de cocaína se ha incrementado extraordinariamente en los últimos años, por lo que resulta indispensable el desarrollo de metodologías seguras, rápidas y eficientes para su detección. En este trabajo se desarrollo una técnica de HPLC de fase reversa con detector de UV para identificar y cuantificar a la cocaína y la benzoilecgonina, con resultados satisfactorios en los parámetros del control de calidad.Se realizó un estudio de recobrado para el aislamiento de la cocaína y la benzoilecgonina en orina con extracciones liquido liquido y en fase sólida con tres tipos de columnas comerciales (Bond Elut Certify, Extrelut 3 y Supelclean LC-18). Las fracciones obtenidas con la extracción líquido-líquido resultaron muy contaminados, con porcentajes de recobrados bajos (45% y 28% para la cocaína y la benzoilecgonina, respectivamente. En las extracciones en fase sólida para la cocaína resultaron muy eficientes las columnas Supelclean LC-18 (87-102 %) y Extrelut 3 (70-102 %), mientras que para el aislamiento de la benzoilecgonina resultaron más eficiente las columnas Extrelut 3 (86-101 %) y Supelclean LC-18 (73-89%). Las columnas Bond Elut Certify resultaron poco eficientes para el aislamiento de la cocaína (53-79%) y con un recobrado aún mas bajo para su metabolito (2-21% %)
Estudio experimental de la extracción de carragenano a partir del alga Iridaea laminarioides
El objetivo de este trabajo fue hacer un estudio de factibilidad técnica de un proceso de extracción de carragenano a partir del alga roja Iridaea laminarioides, considerando que la recolección nacional de algas productoras de este polisacárido bordea las 3.000 Ton/año. Se estableció la influencia que tienen sobre el rendimiento y la calidad del producto obtenido, las variables siguientes: tiempo de extracción, relación volumen de solvente de extracción a masa de alga seca, volumen del agente precipitante, tiempo y velocidad de centrifugación, decoloración, etc. El proceso estudiado proporciona un producto blanco, de viscosidad promedio igual a 50 cp para soluciones al 1% en peso a 25°C y que forma geles fuertes cuando se lo trata con hidróxido de potasio. El rendimiento de producto es 70% y corresponde aproximadamente al 400 /o de la masa inicial de alga seca (19% humedad base seca)
Assessing the potential impact of wind turbines on the endangered Galapagos Petrel Pterodroma phaeopygia at San Cristóbal Island, Galapagos
Continuous atom laser with Bose-Einstein condensates involving three-body interactions
We demonstrate, through numerical simulations, the emission of a coherent
continuous matter wave of constant amplitude from a Bose-Einstein Condensate in
a shallow optical dipole trap. The process is achieved by spatial control of
the variations of the scattering length along the trapping axis, including
elastic three body interactions due to dipole interactions. In our approach,
the outcoupling mechanism are atomic interactions and thus, the trap remains
unaltered. We calculate analytically the parameters for the experimental
implementation of this CW atom laser.Comment: 11 pages, 4 figure
Social-ecological factors influencing tourist satisfaction in three ecotourism lodges in the southeastern Peruvian Amazon
This an accepted author's manuscript (AAM) version of an article published in Tourism Management, 33 (2012) 545-55
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