PTP1B promotes focal complex maturation, lamellar persistence and directional migration

Previous findings established that ER-bound PTP1B targets peripheral cell-matrix adhesions and positively regulates cell adhesion to fibronectin. Here we show that PTP1B enhances focal complex lifetime at the lamellipodium base, delaying their turnover and facilitating α-actinin incorporation. We demonstrate the presence of catalytic PTP1BD181A-α-actinin complexes at focal complexes. Kymograph analysis revealed that PTP1B contributes to lamellar protrusion persistence and directional cell migration. Pull-down and FRET analysis also showed that PTP1B is required for efficient integrin-dependent downregulation of RhoA and upregulation of Rac1 during spreading. A substrate trap strategy revealed that FAK/Src recruitment and Src activity are essential for the generation of PTP1B substrates in adhesions. PTP1B targets the negative regulatory site of Src (phosphotyrosine 529), paxillin and p130Cas at peripheral cell-matrix adhesions. We postulate that PTP1B modulates more than one pathway required for focal complex maturation and membrane protrusion, including α-actinin-mediated cytoskeletal anchorage, integrin-dependent activation of the FAK/Src signaling pathway, and RhoA and Rac1 GTPase activity. By doing so, PTP1B contributes to coordinated adhesion turnover, lamellar stability and directional cell migration.Fil: Burdisso, Juan Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: González, Angela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Arregui, Carlos Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentin

Psychometric Properties of the Alcohol Expectancy Scale in Argentinean Adolescents Applying the Rating Scale Analysis

The goal of this study was to analyze the psychometric properties of the Alcohol Expectancy Scale (AES-AA) applying item response theory. Data were obtained from 592 adolescents enrolled in private and public schools of the city of Córdoba (Argentina). This psychometric study was carried out with the Rating Scale Model (RSM), a polytomous Rasch model. Out of the 45 items that make up the scale, 42 items had adequate fit indexes, explaining 91.3% of the adolescents’ response patterns. The estimation error of the parameters was low, indicating adequate precision of the items. In general, the participants’ scores fell within the range of the continuum where the test is most precise. Adolescents’ least frequent expectancies about alcohol consumption were related to sexual behavior (positive expectancies), whereas their most frequent expectancies corresponded both with the Sociability Scale (positive expectancies) and to the Cognitive and Behavioral Impairment Scale (negative expectancies). Implications for preventive programs are discussed.Fil: Pilatti, Angelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Estudio sobre Cultura y Sociedad. Centro de Investigaciones de la Facultad de Psicología - Grupo Vinculado CIPSI; ArgentinaFil: Godoy, Juan Carlos. Universidad Nacional de Córdoba. Facultad de Psicología. Laboratorio de Psicologia; ArgentinaFil: Lozano, Oscar. Universidad de Huelva; EspañaFil: Brussino, Silvina Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Estudio sobre Cultura y Sociedad. Centro de Investigaciones de la Facultad de Psicología - Grupo Vinculado CIPSI; Argentin

Ascorbic Acid Degradation in PVP Solid Dispersions and the Effects of Water and Pre-lyophilization Solution pH On its Chemical Stability

Ascorbic acid (vitamin C) is an essential micronutrient found both naturally in foods as well as supplemented in fortified foods and dietary supplements. In foods, ascorbic acid typically exists in the aqueous or crystalline solid state, but the lyophilization of ascorbic acid polymer solutions has been proven to render ascorbic acid into the amorphous solid state. This study investigated the importance of two matrix effects – the weight ratio of ascorbic acid to PVP and the pre-lyophilization solution pH – on the chemical degradation of ascorbic acid in the amorphous solid state. Amorphous ascorbic acid was generated via lyophilization with PVP and stored at several controlled temperature conditions and 11% relative humidity. Low pH lyophiles (pH 3.0 and pH 3.5) displayed strongly non-additive moisture sorption behavior while higher pH lyophiles (pH 4.0 and pH 4.5) displayed additive moisture sorption. Changes in the pre-lyophilization solution pH caused up to four-fold increases in the extent of ascorbic acid degradation in lyophiles in spite of similar glass transition temperatures and equal relative humidity storage conditions. Modification of the weight ratio of ascorbic acid to PVP caused over six-fold increases in loss of ascorbic acid during storage. Recrystallized ascorbic acid dispersions showed no significant differences in loss during storage regardless of weight ratio, supporting the importance of the physical state of small molecules on their chemical stability. Given the large differences in chemical stability caused by ascorbic acid to PVP weight ratio and pre-lyophilization solution pH, these two matrix effects should be considered important factors in the chemical stability of small molecules in amorphous solid dispersions

Numerical investigation of the double-arcing phenomenon in a cutting arc torch

A numerical investigation of the double-arcing phenomenon in a cutting arc torch is reported. The dynamics of the double-arcing were simulated by using a two-dimensional model of the gas breakdown development in the space-charge layer contiguous to the nozzle of a cutting arc torch operated with oxygen. The kinetic scheme includes ionization of heavy particles by electron impact, electron attachment, electron detachment, electron-ion recombination, and ion-ion recombination. Complementary measurements during double-arcing phenomena were also conducted. A marked rise of the nozzle voltage was found. The numerical results showed that the dynamics of a cathode spot at the exit of the nozzle inner surface play a key role in the raising of the nozzle voltage, which in turn allows more electrons to return to the wall at the nozzle inlet. The return flow of electrons thus closes the current loop of the double-arcing. The increase in the (floating) nozzle voltage is due to the fact that the increased electron emission at the spot is mainly compensated by the displacement current (the ions do not play a relevant role due to its low-mobility) until that the stationary state is achieved and the electron return flow fully-compensates the electron emission at the spot. A fairly good agreement was found between the model and the experiment for a spot emission current growth rate of the order of 7×104A/s. © 2014 AIP Publishing LLC.Fil: Mancinelli, Beatriz Rosa. Universidad Tecnológica Nacional. Facultad Regional Venado Tuerto; ArgentinaFil: Minotti, Fernando Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; ArgentinaFil: Prevosto, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; ArgentinaFil: Kelly, Hector Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; Argentin

Regularity theory and high order numerical methods for the (1D)-fractional Laplacian

This paper presents regularity results and associated high-order numerical methods for one-dimensional Fractional-Laplacian boundary-value problems. On the basis of a factorization of solutions as a product of a certain edge-singular weight $w$ times a ``regular´´ unknown, a characterization of the regularity of solutions is obtained in terms of the smoothness of the corresponding right-hand sides. In particular, for right-hand sides which are analytic in a Bernstein Ellipse, analyticity in the same Bernstein Ellipse is obtained for the ``regular´´ unknown. Moreover, a sharp Sobolev regularity result is presented which completely characterizes the co-domain of the Fractional-Laplacian operator in terms of certain weighted Sobolev spaces introduced in (Babu{s}ka and Guo, SIAM J. Numer. Anal. 2002). The present theoretical treatment relies on a full eigendecomposition for a certain weighted integral operator in terms of the Gegenbauer polynomial basis. The proposed Gegenbauer-based Nystr"om numerical method for the Fractional-Laplacian Dirichlet problem, further, is significantly more accurate and efficient than other algorithms considered previously. The sharp error estimates presented in this paper indicate that the proposed algorithm is spectrally accurate, with convergence rates that only depend on the smoothness of the right-hand side. In particular, convergence is exponentially fast (resp. faster than any power of the mesh-size) for analytic (resp. infinitely smooth) right-hand sides. The properties of the algorithm are illustrated with a variety of numerical results.Fil: Acosta, Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; ArgentinaFil: Borthagaray, Juan Pablo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; ArgentinaFil: Bruno, Oscar Ricardo. California Institute Of Technology; Estados UnidosFil: Maas, Martín Daniel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Landau level transitions indoped graphene in a time dependent magnetic field

The aim of this work is to describe the Landau levels transitions of Bloch electrons in doped graphene with an arbitrary time dependent magnetic field in the long wavelength approximation. In particular, transitions from the m Landau level to the m + 1 and m + 2 Landau levels are studied using time-dependent perturbation theory. Time intervals are computed in which transition probabilities tend to zero at low order in the coupling constant. In particular, Landau level transitions are studied in the case of Bloch electrons travelling in the direction of the applied magnetic force and the results are compared with classical and revival periods of electrical current in graphene. Finally, current probabilities are computed for the n = 0 and n = 1 Landau levels showing expected oscillating behavior with modified cyclotron frequency.Comment: 18 pages, 7 figure

The convenience store format as a mean of proximity of services and supply in urban areas

This work analyzes the format of Oxxo’s convenience store as a mean of proximity of services and supplies within Toluca Metropolitan Area (AMT). It describes their geographical distribution, the contextual features of their locational structure and part of the relationship between mobility and functionality between services and products offered to their consumers. The research is based on statistical and documentary analysis, which uses several spatial analysis techniques through Geographic Information Systems (GIS). The article concludes that Oxxo’s chain, as well as different business firms; structures its branches according to the spatial context of its customers and, in some cases, in relation to other business (clusters, shopping malls). Additionally, the firm approximates products and services from other institutions (cable, banking, telephone, and many others) that transform it, sometimes, in a correspondent or stop payment, providing new mobility options at urban level. Finally, the potential accessibility level is evaluated for the total and employed population, with the aim to measure the level of access that these units have and it is showed that the localization pattern of the chain as well as the more accessible areas are concentrated in the center of the AMT, also it gradually decrease toward the periphery. Oxxo’s firm is one of the formats of greater coverage within the AMT – and perhaps in others cities of the country- allowing it to obtain the territorial conquest in coverage of the urban area.El presente artículo analiza el formato de tiendas de conveniencia de la cadena Oxxo, como medio de proximidad en servicios y abastecimiento dentro del Área Metropolitana de Toluca (AMT). Describe su distribución geográfica, las características contextuales de su estructura locacional, así como parte de la relación de movilidad y funcionalidad entre los servicios y productos que oferta con sus consumidores. La investigación está basada en un análisis estadístico y documental, donde se emplean diversas técnicas de análisis espacial por medio de Sistemas de Información Geográfico (SIG). El texto concluye que la cadena Oxxo, al igual que diferentes firmas comerciales, estructura sus sucursales de acuerdo con el contexto espacial de sus clientes y, en algunos casos, con relación a otras actividades comerciales (clusters, plazas comerciales, por ejemplo); adicionalmente, la firma aproxima productos y servicios de otras instituciones (pagos de tv por cable, bancarios, telefónicos, entre muchos otros) que lo convierten, en algunos casos, como corresponsal o ventanilla de pago, otorgando nuevas opciones de movilidad a nivel urbano. Finalmente, se evalúa el nivel de accesibilidad potencial para la Población Total (PT) y Población Ocupada (PO) a fin de medir el nivel de oportunidad que se tienen a estas unidades y se demuestra que el patrón de localización de la cadena y las zonas de mayor accesibilidad se concentran en el centro del AMT y disminuyen gradualmente hacia la periferia. La firma Oxxo es uno de los formatos de mayor cobertura dentro del AMT –y quizá de otras ciudades del país– lo que le permite obtener así la “conquista territorial” respecto a cobertura del área urbana en cuestión

Un modelo postclásico-postkeynesiano

En este artículo presentamos una de las múltiples síntesis concebibles entre los paradigmas postclásico (o neorricardiano) y postkeynesiano. Entre los rasgos más destacados del modelo citaremos tres. (1) Una teoría del valor y la distribución basada en los precios de producción de Sraffa que, al combinarse con el sistema postkeynesiano de los precios administrados, nos permite determinar el nivel general de precios, junto a los precios relativos. (2) Una teoría del output basada en el principio keynesiano de la demanda efectiva cuya trascendencia se refuerza al hacerlo descansar sobre el multiplicador estructural y el acelerador prospectivo. (3) Un modelo de dinero endógeno que reconoce, no obstante, las interferencias que las variables financieras pueden causar en el circuito real de la economía.A Postclassical-Postkeynesian Model. This paper presents one of the many feasible synthesis between the postclassical (or neoRicardian) paradigm and the post- Keynesian one. Among the most remarkable features of the model we shall refer to the following ones. (1) A theory of value and distribution based on the Sraffian prices of production that, one combined with the postKeynesian system of administered prices, allows us to determine the general level of prices, in addition to relative prices. (2) A theory of output based on the Keynesian principle of effective demand whose significance is reinforced when it rests on the structural multiplier and the prospective accelerator. (3) A model of endogenous money that admits, notwithstanding, the interferences of the financial variables in the real circuit of the economy