268 research outputs found

    Optical multi-trapping by Kinoform m-Bonacci lenses

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    [EN] Optical manipulation is interfacing disciplines in the micro and nanoscale, from molecular biology to quantum computation. Versatile solutions for increasingly more sophisticated technological applications require multiple traps with which to maneuver dynamically several particles in three dimensions. The axial direction is usually overlooked due to difficulties in observing particles away from an objective-lens focal plane, a normal element in optical tweezers, and in managing interparticle distances along the trapping beam propagating direction, where strong radiation pressure and shadowing effects compromise the simultaneous and stable confinement of the particles. Here, aperiodic kinoform diffractive lens based on the m-Bonacci sequence are proposed as a newtrapping strategy. This lens provides split first-order diffractive foci whose separation depends on the generalized m-golden ratio. We show the extended manipulation capabilities of a laser tweezers system generated by these lens, in which concomitant trapping of particles in different focal planes takes place. Positioning particles in the axial direction with computer-controlled distances allows dynamic three-dimensional all-optical lattices, useful in a variety of microscale and nanoscale applications. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing AgreementMinisterio de Ciencia e Innovacion (PID2019-107391RB-I00); Generalitat Valenciana (PROMETEO/2019/048); Universitat Politecnica de Valencia (PAID-01-20-25).Muñoz-Pérez, FM.; Ferrando, V.; Furlan, WD.; Monsoriu Serra, JA.; Arias-Gonzalez, JR. (2022). Optical multi-trapping by Kinoform m-Bonacci lenses. Optics Express. 30(19):34378-34384. https://doi.org/10.1364/OE.4656723437834384301

    Solving the stellar 62Ni problem with AMS

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    An accurate knowledge of the neutron capture cross sections of 62,63Ni is crucial since both isotopes take key positions which affect the whole reaction flow in the weak s process up to A=90. No experimental value for the 63Ni(n,gamma) cross section exists so far, and until recently the experimental values for 62Ni(n,gamma) at stellar temperatures (kT=30 keV) ranged between 12 and 37 mb. This latter discrepancy could now be solved by two activations with following AMS using the GAMS setup at the Munich tandem accelerator which are also in perfect agreement with a recent time-of-flight measurement. The resulting (preliminary) Maxwellian cross section at kT=30 keV was determined to be 30keV = 23.4 +/- 4.6 mb. Additionally, we have measured the 64Ni(gamma,n)63Ni cross section close to threshold. Photoactivations at 13.5 MeV, 11.4 MeV and 10.3 MeV were carried out with the ELBE accelerator at Forschungszentrum Dresden-Rossendorf. A first AMS measurement of the sample activated at 13.5 MeV revealed a cross section smaller by more than a factor of 2 compared to NON-SMOKER predictions.Comment: Proceedings of the 11th International Conference on Accelerator Mass Spectrometry in Rome, Sept. 14-19, 2008; to be published in Nucl. Instr. Meth.

    Tissue oxygenation with graded dissolved oxygen delivery during cardiopulmonary bypass

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    AbstractBackground: Intravascular perfluorochemical emulsions together with a high oxygen tension may increase the delivery of dissolved oxygen to useful levels. The hypothesis of this study is that increasing the dissolved oxygen content of blood with incremental doses of a perfluorochemical emulsion improves tissue oxygenation during cardiopulmonary bypass in a dose-related fashion. Methods and Results: Oxygen utilization was studied in a profoundly anemic canine model of hypothermic cardiopulmonary bypass. Forty-two dogs (mean ± standard error of the mean). Cardiopulmonary bypass was begun and resulted in a hematocrit of 9.4% + 0.6%. A standard primng solution was used in the control group (n = 12), and the test groups received 1.35 gm perfluorochemical · kg-1 (n = 10 dogs), or 5.4 gm perfluorochemical · kg-1 (n = 10 dogs), 2.7 gm perfluorochemical · kg-1(n = 10 dogs) through the venous return cannula. Each animal underwent a series of randomized pump flows (0.25,0.5, 1.0, 1.5, 2.0, and 3.0 L · min-1 · m-2 ) at 32° C. After the randomized flows were completed at 32° C, the temperature was raised to 38° C and cardiopulmonary bypass was discontinued. Mortality from cardiac failure on separation from cardiopulmonary bypass was 42% in the control group and 20% in perfluorochemical-treated groups. The mean perfluorochemical dose was higher in surviviors than in nonsurvivors (2.9 + 0.4 versus 1.3 + 0.5 gm perfluorochemical · kg-1; p < 0.05). No differences in oxygen consumption or transbody lactate gradient were found between groups during cardiopulmonary bypass. Analysis of mixed venous oxygen tension (a surrogate measure for tissue oxygenation) as a function of cardiopulmonary bypass flow normalized to body surface area showed that the control group had significantly lower mixed venous oxygen tension (p < 0.05) than the perfluorochemical emulsion-treated groups. Furthermore, the differences were related to the perfluorochemical emulsion dose. These differences in mixed venous oxygen tension continued after termination of cardiopulmonary bypass. The coronary sinus oxygen tension and cardiac arterial-venous oxygen content differences during and after cardiopulmonary bypass were similar among the control and perfluorochemical emulsion-treated animals. Dissolved oxygen consumption during and after cardiopulmonary bypass was calculated. Dissolved oxygen consumption increased in the perfluorochemical-treated animals in a perfluorochemical dose-related manner and was significantly higher in perfluoro-chemical-treated animals than in the control animals (p < 0.05). Conclusions: Graded increases in mixed venous oxygen tension during cardiopulmonary bypass were observed in response to graded increases in the dissolved oxygen delivery. These data suggest that enhancing oxygenation with perfluorochemical-dissolved oxygen is an effective temporary substitute for the use of hemoglobin-bound oxygen during cardiopulmonary bypass. Perfluorochemical-dissolved oxygen may be particularly beneficial in the setting of multiple hypoxic stresses. (J THORAC CARDIOVASC SURG 1995;110: 774-85)J THORAC CARDIOVASC SURG 1995;110:1-85

    COMPLICAÇÕES RESPIRATÓRIAS NO PÓS-OPERATÓRIO

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    Complications related to respiratory system are not uncommon after major surgeries and increase morbidity and mortality. Among the most frequent are atelectasis, pneumonia, respiratory failure and pulmonary thromboembolism. In this article we revised in brief the general aspects of pathophysiology, clinical presentation, diagnosis and clinical management of these conditions.As complicações relacionadas ao sistema respiratórias não são incomuns no pósoperatório de operações de maior porte e aumentam a morbidade e mortalidade. Entre as mais freqüentes estão a atelectasia, a pneumonia, o tromboembolismo pulmonar e a falência respiratória. No presente artigo são revisados resumidamente os aspectos gerais da fisiopatologia, a apresentação clínica, o diagnóstico e o manuseio clínico dessas entidades

    Uncovering the Origins of Spiral Structure by Measuring Radial Variation in Pattern Speeds

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    Current theories of spiral and bar structure predict a variety of pattern speed behaviors, calling for detailed, direct measurement of the radial variation of pattern speeds. Our recently developed Radial Tremaine-Weinberg (TWR) method allows this goal to be achieved for the first time. Here we present TWR spiral pattern speed estimates for M101, IC 342, NGC 3938 and NGC 3344 in order to investigate whether spiral structure is steady or winding, whether spirals are described by multiple pattern speeds, and the relation between bar and spiral speeds. Where possible, we interpret our pattern speeds estimates according to the resonance radii associated with each (established with the disk angular rotation), and compare these to previous determinations. By analyzing the high-quality HI and CO data cubes available for these galaxies, we show that it is possible to determine directly multiple pattern speeds within these systems, and hence identify the characteristic signatures of the processes that drive the spiral structure. Even this small sample of galaxies reveals a surprisingly complex taxonomy, with the first direct evidence for the presence of resonant coupling of multiple patterns found in some systems, and the measurement of a simple single pattern speed in others. Overall, this study demonstrates that we are now in a position to uncover more of the apparently complex physics that lies behind spiral structure.Comment: 15 pages in emulateapj format, 12 figures, accepted for publication in Ap

    Research opportunities for argumentation in social networks

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    Nowadays, many websites allow social networking between their users in an explicit or implicit way. In this work, we show how argumentation schemes theory can provide a valuable help to formalize and structure on-line discussions and user opinions in decision support and business oriented websites that held social networks between their users. Two real case studies are studied and analysed. Then, guidelines to enhance social decision support and recommendations with argumentation are provided.This work summarises results of the authors joint research, funded by an STMS of the Agreement Technologies COST Action 0801, by the Spanish government grants [CONSOLIDER-INGENIO 2010 CSD2007-00022, and TIN2012-36586-C03-01] and by the GVA project [PROMETEO 2008/051].Heras Barberá, SM.; Atkinson, KM.; Botti Navarro, VJ.; Grasso, F.; Julian Inglada, VJ.; Mcburney, PJ. (2013). Research opportunities for argumentation in social networks. 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In: Proceedings of the second international conference on computational models of argument (COMMA 2008), pp 116–127Chesñevar C, McGinnis J, Modgil S, Rahwan I, Reed C, Simari G, South M, Vreeswijk G, Willmott S (2006) Towards an argument interchange format. Knowl Eng Rev 21(4):293–316Chesñevar CI, Maguitman AG, Gonzàlez MP (2009) Empowering recommendation technologies through argumentation. Argumentation in artificial intelligence. Springer, Berlin, pp 403–422García AJ, Dix J, Simari GR (2009) Argument-based logic programming. Argumentation in artificial intelligence. Springer, BerlinGolbeck J (2006) Generating predictive movie recommendations from trust in social networks. In: Proceedings of the fourth international conference on trust management, LNCS, vol 3986, 93–104Gordon T, Prakken H, Walton D (2007) The Carneades model of argument and burden of proof. Artif Intell 171(10–15):875–896Guha R, Kumar R, Raghavan P, Tomkins A (2004) Propagating trust and distrust. In: Proceedings of the 13th international conference on, World Wide Web, pp 403–412Heras S, Navarro M, Botti V, Julián V (2009) Applying dialogue games to manage recommendation in social networks. In: Proceedings of the 6th international workshop on argumentation in multi-agent aystems, ArgMASHeras S, Atkinson K, Botti V, Grasso F, Julián V, McBurney P (2010a) How argumentation can enhance dialogues in social networks. In: Proceedings of the 3rd international conference on computational models of argument, COMMA, vol 216, pp 267–274Heras S, Atkinson K, Botti V, Grasso F, Julián V, McBurney P (2010b) Applying argumentation to enhance dialogues in social networks. In: ECAI 2010 workshop on computational models of natural argument, CMNA, pp 10–17Karacapilidis N, Tzagarakis M (2007) Web-based collaboration and decision making support: a multi-disciplinary approach. Web-Based Learn Teach Technol 2(4):12–23Kim D, Benbasat I (2003) Trust-related arguments in internet stores: a framework for evaluation. J Electron Commer Res 4(2):49–64Kim D, Benbasat I (2006) The effects of trust-assuring arguments on consumer trust in internet stores: application of Toulmin’s model of argumentation. Inf Syst Rese 17(3):286–300Laera L, Tamma V, Euzenat J, Bench-Capon T, Payne T (2006) Reaching agreement over ontology alignments. In: Proceedings of the 5th international semantic web conference (ISWC 2006)Lange C, Bojãrs U, Groza T, Breslin J, Handschuh S (2008) Expressing argumentative discussions in social media sites. In: Social data on the web (SDoW2008) workshop at the 7th international semantic web conferenceLinden G, Smith B, York J (2003) Amazon.com recommendations: item-to-item collaborative filtering. IEEE Internet Comput 7(1):76–80Linden G, Hong J, Stonebraker M, Guzdial M (2009) Recommendation algorithms, online privacy and more. 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    Measurements of high-energy neutron-induced fission of (nat)Pb and (209)Bi

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial License 3.0, which permits unrestricted use, distribution, and reproduction in any noncommercial medium, provided the original work is properly citedThe CERN Neutron Time-Of-Flight (n_TOF) facility is well suited to measure low cross sections as those of neutron-induced fission in subactinides. The cross section ratios of (nat)Pb and (209)Bi relative to (235)U and (238)U were measured using PPAC detectors and a fragment coincidence method that allows us to identify the fission events. The present experiment provides first results for neutron-induced fission up to 1 GeV. Good agreement is found with previous experimental data below 200 MeV. The comparison with proton-induced fission indicates that the limiting regime where neutron-induced and proton-induced fission reach equal cross sections is close to 1 GeV

    EFECTO ANTIOXIDANTE Y ANTIFOTOENVEJECIMIENTO DE EXTRACTOS DE LA MACROALGA DEL LITORAL PERUANO DE Macrocystis integrifolia BORY Y ELABORACIÓN DE UNA FORMA DERMOCOSMÉTICA

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    The aim of the study was to evaluate the antioxidant and antiphotoaging effects of extracts of brown alga Macrocystis integrifolia Bory and develop a dermocosmetic form. From this extracts, was designed the dermocosmetic form in concentrations of 1, 3 and 5%, on a base made of lard with incorporation of beeswax and sesame oil to a pH of 6,5. The antioxidant activity was determined by in vitro methods as CDP and ABTS. The evaluation of antiphotoaging effect in vivo was performed using 25 albino female mice of Mus musculus specie, strain Bald / C53, who were divided into five groups of five mice each; except the group that served as blank, control and intervention groups were depilated hair back and subjected to UVB irradiation for 7 days, morning and night. The in vitro antioxidant activity assay showed that between extracts from stem, foliage and bulb of this alga, there are differences in antioxidant capacity against free radical ABTS, stating that the lower IC50 value (173,21 µg/mL) frond abstract presents higher total antioxidant capacity than the IC50 (3,23 µg/mL) value of Trolox, reference substance. In the trial CDP an IC50 value (669,7 µg/mL) was above the standard of ascorbic acid IC50 (33 µg/mL). Antiphotoaging analysis showed, at macro and microscopic levels, favorable notable differences in the intervention groups. Was conclude that brown seaweed extracts studied have antioxidant effect in vitro and antiphotoaging in vivo.El objetivo del estudio fue evaluar el efecto antioxidante y antifotoenvejecimiento de extractos de la alga parda Macrocystis integrifolia Bory y elaborar una forma dermocosmética. Obtenidos los extractos, se diseñó una forma dermocosmética en concentraciones de 1, 3 y 5%, elaboradas sobre una base de manteca de cerdo con incorporación de cera de abejas y aceite de sésamo a un pH de 6,5. La actividad antioxidante in vitro se determinó por lo métodos CDP y ABTS. La evaluación del efecto antifotoenvejecimiento in vivo se realizó empleando 25 ratones albinos hembra de la especie Mus musculus, cepa Bald/C53, que fueron distribuidos en cinco grupos de cinco ratones cada uno; a excepción del grupo que sirvió de blanco, el grupo control y los grupos de intervención fueron depilados en el lomo y se sometieron a la irradiación UVB durante 7 días, mañana y noche. El ensayo in vitro de la actividad antioxidante mostró que entre los extractos de estípite, fronda y bulbo de esta alga, existen diferencias en la capacidad antioxidante frente al radical libre ABTS, evidenciándose que el menor valor de IC50 (173,21 µg/mL) del extracto de fronda presenta mayor capacidad antioxidante total que el valor IC50 (3,23 µg/mL) de Trólox, sustancia de referencia. En el ensayo CDP se tuvo un valor de IC50 (669,7 µg/mL) por encima del estándar del ácido ascórbico IC50 (33 µg/mL). En el análisis antifotoenvejecimiento se observó, a niveles macro y microscópicos, notables diferencias favorables en los grupos de intervención. Se concluye que los extractos del alga parda estudiada tienen efecto antioxidante in vitro y antifotoenvejecimiento in vivo

    The Ustilago maydis Effector Pep1 Suppresses Plant Immunity by Inhibition of Host Peroxidase Activity

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    The corn smut Ustilago maydis establishes a biotrophic interaction with its host plant maize. This interaction requires efficient suppression of plant immune responses, which is attributed to secreted effector proteins. Previously we identified Pep1 (Protein essential during penetration-1) as a secreted effector with an essential role for U. maydis virulence. pep1 deletion mutants induce strong defense responses leading to an early block in pathogenic development of the fungus. Using cytological and functional assays we show that Pep1 functions as an inhibitor of plant peroxidases. At sites of Δpep1 mutant penetrations, H2O2 strongly accumulated in the cell walls, coinciding with a transcriptional induction of the secreted maize peroxidase POX12. Pep1 protein effectively inhibited the peroxidase driven oxidative burst and thereby suppresses the early immune responses of maize. Moreover, Pep1 directly inhibits peroxidases in vitro in a concentration-dependent manner. Using fluorescence complementation assays, we observed a direct interaction of Pep1 and the maize peroxidase POX12 in vivo. Functional relevance of this interaction was demonstrated by partial complementation of the Δpep1 mutant defect by virus induced gene silencing of maize POX12. We conclude that Pep1 acts as a potent suppressor of early plant defenses by inhibition of peroxidase activity. Thus, it represents a novel strategy for establishing a biotrophic interaction
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