A 5 Meps $100 USB2.0 Address-Event Monitor-Sequencer Interface

This paper describes a high-speed USB2.0 Address- Event Representation (AER) interface that allows simultaneous monitoring and sequencing of precisely timed AER data. This low-cost (<$100), two chip, bus powered interface can achieve sustained AER event rates of 5 megaevents per second (Meps). Several boards can be electrically synchronized, allowing simultaneous synchronized capture from multiple devices. It has three AER ports, one for sequencing, one for monitoring and one for passing through the monitored events. This paper also describes the host software infrastructure that makes the board usable for a heterogeneous mixture of AER devices and that allows recording and playback of recorded data

Effects of non-unity Lewis numbers in diffusion Flames

The purpose of this work is to carry out direct numerícal simulations of diffusion controlled combustión with non-unity Lewis numbers for the reactants and producís, thus accounting for the düferential diífusion effects of the temperature and concentration fields. We use a formulation (Liñán (1991a)) based on combining the conservation equations in a way to elimínate the reaction terms similar to the method used by Burke and Schumann (1928) for unity Lewis numbers. We present calculations for an axisymmetric fuel jet and for a planar, time evolving mixing layer, leaving out the effects of thermal expansión and variations of the transport coefficients due to the heat reisase. Our results show that the front of the fíame sbifts toward the fuel or oxygen sides owing to the effect of the düferential diífusion and that the location of máximum temperature may not coincide with the fíame. The dependence of the distríbution of the reaction products on their Lewis number has been investigated

Dipole-dipole interaction between a quantum dot and graphene nanodisk

We study theoretically the dipole-dipole interaction and energy transfer in a hybrid system consisting of a quantum dot and graphene nanodisk embedded in a nonlinear photonic crystal. In our model a probe laser field is applied to measure the energy transfer between the quantum dot and graphene nanodisk while a control field manipulates the energy transfer process. These fields create excitons in the quantum dot and surface plasmon polaritons in the graphene nanodisk which interact via the dipole-dipole interaction. Here the nonlinear photonic crystal acts as a tunable photonic reservoir for the quantum dot, and is used to control the energy transfer. We have found that the spectrum of power absorption in the quantum dot has two peaks due to the creation of two dressed excitons in the presence of the dipole-dipole interaction. The energy transfer rate spectrum of the graphene nanodisk also has two peaks due to the absorption of these two dressed excitons. Additionally, energy transfer between the quantum dot and the graphene nanodisk can be switched on and off by applying a pump laser to the photonic crystal or by adjusting the strength of the dipole-dipole interaction. We show that the intensity and frequencies of the peaks in the energy transfer rate spectra can be modified by changing the number of graphene monolayers in the nanodisk or the separation between the quantum dot and graphene. Our results agree with existing experiments on a qualitative basis. The principle of our system can be employed to fabricate nano-biosensors, optical nano-switches, and energy transfer devices

On the Design of Ambient Intelligent Systems in the Context of Assistive Technologies

The design of Ambient Intelligent Systems (AISs) is discussed in the context of assistive technologies. The main issues include ubiquitous communications, context awareness, natural interactions and heterogeneity, which are analyzed using some examples. A layered architecture is proposed for heterogeneous sub-systems integration with three levels of interactions that may be used as a framework to design assistive AISs.Ministerio de Ciencia y Tecnología TIC2001-1868-C0

Liver radioembolization: Computational particle–hemodynamics studies in a patient-specific hepatic artery under literature-based cancer scenarios.

Liver radioembolization is a promising treatment for combating primary and metastatic liver tumors. It consists of administering radioactive microspheres via an intraarterially placed microcatheter with the aim of lodging these microspheres, which are driven by the arterial bloodstream, in the tumoral bed. The position of the microcatheter and the microsphere injection velocity are decided during a pretreatment assessment, by which the treatment is mimicked via the infusion of macroaggregated albumin microparticles. It is assumed that the pretreatment microcatheter placement and microsphere injection velocity are reproduced during the treatment. Even though it is a safe and effective treatment, some complications (e.g., radiation-induced hepatitis or pneumonitis, gastrointestinal ulcers, etc.) may arise due to nontarget radiation, which can occur due to differences between pretreatment and treatment injection conditions related to microcatheter placement, the injection itself, and the patient’s bloodstream. In terms of microcatheter placement, there are a number of parameters that can vary from pretreatment to treatment. Of those, the ones that are of special interest in this thesis are the longitudinal and radial position of the microcatheter tip, the microcatheter’s distal direction, the expandable-tip presence (for antireflux catheters only), and the tip orientation (for angled-tip microcatheters only). As for the injection itself, of the parameters that can be modified, this thesis is most concerned with two of them: the quantity and size of the microagent, and the particle injection velocity. With regard to the bloodstream, the arterial blood flow conditions might vary, e.g., due to microsphere-caused embolization of arterioles, leading to a reflux of microspheres. Any alteration in these parameters may be responsible for nontarget radiation and therefore radiation-induced complications. In order to reduce these radiation-induced complications, it has been suggested that the pretreatment injection conditions be matched as closely as possible during treatment. An alternative solution is to modify the design of microcatheters. For instance, it has been reported that using an antireflux catheter has eliminated particle reflux. The aim of this thesis is to analyze the influence of the abovementioned parameters on microsphere distribution via computational fluid–particle dynamics simulations. The thesis is divided into four major studies, each of which follows the same numerical strategy (i.e., the liver radioembolization is simulated in a patient-specific hepatic artery model under literature-based liver cancer scenarios). The first study analyzes the pretreatment as an actual treatment surrogate, the second analyzes the influence of an antireflux catheter, the third investigates the influence of the microcatheter distal direction and the injection point and velocity, and the last one explores the influence of an angled-tip microcatheter. Furthermore, prior to conducting these four studies, a methodology was developed to define realistic boundary conditions for numerical simulations in hepatic arteries. For the study on the pretreatment, results suggest that microcatheter placement is of paramount importance, both in terms of its location in the artery (near a bifurcation or not) and in the longitudinal shifting in microcatheter tip locations between pretreatment and actual treatment. Moreover, the higher the cancer burden, the better the tumor targeting because of the enhanced particle transport power. For the study on antireflux catheter influence, the main conclusion that can be drawn is that injecting from a sufficiently long and tortuous artery branch may ensure a downstream particle distribution that matches flow split, almost regardless of catheter type due to the likely adequate conditions for microsphere redistribution in the bloodstream. With regard to the third study, despite the importance of microcatheter tip position, microcatheter direction and injection velocity seem also to play an important role in particle distribution; results show that unintentional modifications to microcatheter tip and direction and injection velocity during tumor targeting may influence procedure outcome. The final study involving the angled-tip microcatheter shows that the higher the injection velocity the more spread out the particle distribution across cross-sectional areas of artery lumen. Moreover, when only focusing on tip orientation, it is not possible to accurately predict which branch of the bifurcation will take the particles because the complex geometry of hepatic arteries makes the bloodstream take the form of helical and chaotic streamlines. This means that the particle pathlines are not initially intuitive, even though the particle distribution will be similar to flow split.La radioembolización hepática es un tratamiento para combatir tumores hepáticos primarios y metástasis hepáticas. Consiste en administrar microesferas radiactivas mediante un microcatéter situado en la arteria hepática, de modo que esas microesferas, que son llevadas por la corriente sanguínea, se depositan en la malla tumoral. La posición del microcatéter y la velocidad de inyección de las partículas se deciden durante el pretratamiento, mediante el cual se emula el tratamiento por medio de la infusión de micropartículas de macroagregados de albúmina. Se supone que tanto la posición del microcatéter como la velocidad de inyección se repiten durante el tratamiento. Aunque sea un tratamiento seguro y efectivo, pueden aparecer complicaciones (hepatitis, neumonitis, úlceras gastrointestinales, etc.) por la irradiación de zonas que no debían irradiarse. Esta irradiación no deseada puede deberse a diferencias entre las condiciones de la inyección del pretratamiento y las del tratamiento. Esas condiciones son: el posicionamiento del microcatéter, la inyección y el flujo sanguíneo. En lo que respecta al posicionamiento del microcatéter, los parámetros que pueden variar del pretratamiento al tratamiento, entre otros, son: las posiciones longitudinal y radial de la punta del microcatéter, el direccionamiento distal del microcatéter, la presencia de una punta expandible (para el caso del catéter antirreflujo) y la orientación de la punta del microcatéter (sólo para los microcatéteres con la punta a 45º). En cuanto a la inyección, los parámetros que pueden ser alterados son: el tamaño y la cantidad del microagente inyectado, y la velocidad de inyección de las partículas, entre otros. En cuanto al flujo sanguíneo, éste puede variar, por ejemplo, debido a la embolización de las arteriolas, lo que puede conllevar el reflujo de partículas. La variación de los citados parámetros puede ocasionar irradiación no deseada, lo que conlleva complicaciones debidas a dicha irradiación. Para reducir estas complicaciones, por un lado se ha recomendado ajustar, durante el tratamiento, la posición del microcatéter y la velocidad de inyección definidas durante el pretratamiento. Por otro lado, se han propuesto diferentes diseños de microcatéteres. Por ejemplo, el reflujo de partículas se ha eliminado gracias al catéter antirreflujo. El objetivo de esta tesis es analizar la influencia de los parámetros citados en la distribución de microesferas mediante simulaciones numéricas del flujo de sangre con transporte de partículas. La tesis se divide en cuatro estudios que siguen la misma estrategia de simulación; es decir, la radioembolización es simulada en un modelo de arteria hepática específica de paciente bajo unos escenarios de cáncer basados en la literatura. El primer estudio analiza las diferencias que pueden darse entre el pretratamiento y el tratamiento. El segundo, estudia la influencia del catéter antirreflujo. El tercero, la influencia de la dirección distal del microcatéter, del punto de inyección y de la velocidad de inyección; y el cuarto, la influencia del microcatéter acabado con la punta a 45º. Además, antes de llevar a cabo estos cuatro estudios se tuvo que desarrollar una metodología para definir condiciones de contorno realistas aplicables a simulaciones numéricas en arterias hepáticas. En lo que respecta al estudio sobre el pretratamiento, los resultados muestran que la posición del microcatéter es muy importante, tanto en su posición en la arteria (cerca o lejos de una bifurcación) como en pequeños movimientos longitudinales de la punta del microcatéter entre el pretratamiento y el tratamiento. Además, cuanto mayor es el volumen de cáncer, tanto mayor es la capacidad de llegar a los tumores porque aumenta la capacidad de transportar las partículas. En cuanto al estudio sobre el catéter antirreflujo, la conclusión principal es que inyectar en una arteria lo suficientemente larga y tortuosa posibilita el alineamiento de las partículas con el flujo; de modo que, sea cual sea el catéter empleado para la inyección, la distribución de partículas tiende a parecerse a la distribución del flujo de sangre. Con respecto al tercer estudio, se concluye que a pesar de la importancia de la posición de la punta del microcatéter, también son importantes tanto la dirección distal del microcatéter como la velocidad de inyección de las partículas. Así, variaciones involuntarias de cualquiera de los tres parámetros puede conllevar resultados no deseados en el tratamiento. Por último, el cuarto estudio muestra que cuanto mayor es la velocidad de inyección de las partículas, más esparcidas viajan las partículas en el lumen de la arteria. Además, fijándose únicamente en la orientación de la punta del microcatéter no es posible predecir la rama de la bifurcación que van a tomar las partículas porque la complejidad de la geometría de las arterias hepáticas hace que el flujo sanguíneo tome estructuras hemodinámicas helicoidales y caóticas, por lo que la trayectoria de las partículas no es intuitiva, aunque la distribución de las partículas será similar a la del flujo de sangre

Passive Behavior and Passivity Breakdown of AISI 304 in LiBr Solutions through Scanning Electrochemical Microscopy

The passive behavior and passivity breakdown of AISI 304 stainless steel in LiBr solutions has been investigated by means of scanning electrochemical microscopy (SECM). The sample generation - tip collection (SG-TC) mode was used to operate the SECM and the tip potential was biased to detect the electroactive species. The evolution of the current at the ultramicroelectrode tip with the applied potential within the passive range was followed at different LiBr concentrations. Results show that the absolute value of the current at the tip increases with the applied potential. Additionally, SECM was also used to detect stable pits formed on the stainless steel surface in a 0.2 M LiBr solution. The results show clear evidence of the presence of high amounts of other reducible species (metal cations) apart from oxygen. Also, the dish-shape morphology of the pits observed using Confocal Laser Scanning Microscopy will be discussed in relation to the kinetics of the reactions observed using SECM. (c) 2014 The Electrochemical Society. All rights reserved.The authors would like to express their gratitude to the Generalitat Valenciana for its help in the SECM acquisition (PPC/2011/013) and in the CLSM acquisition (MY08/ISIRM/S/100) and to Dr. Asuncion Jaime for her translation assistance.Fernández Domene, RM.; Sánchez Tovar, R.; García Antón, J. (2014). Passive Behavior and Passivity Breakdown of AISI 304 in LiBr Solutions through Scanning Electrochemical Microscopy. Journal of The Electrochemical Society. 161(12):565-572. https://doi.org/10.1149/2.1051412jesS56557216112Cobb Harold M. (Ed.), Steel Products Manual: Stainless Steels, Iron & Steel Society, 1999.Schweitzer P. A. , Corrosion Engineering Handbook: Fundamentals of Metallic Corrosion, CRC Press, Boca Ratón, FL., 2007.Hakiki, N. B., Boudin, S., Rondot, B., & Da Cunha Belo, M. (1995). The electronic structure of passive films formed on stainless steels. Corrosion Science, 37(11), 1809-1822. doi:10.1016/0010-938x(95)00084-wWijesinghe, T. L. S. L., & Blackwood, D. J. (2008). Photocurrent and capacitance investigations into the nature of the passive films on austenitic stainless steels. Corrosion Science, 50(1), 23-34. doi:10.1016/j.corsci.2007.06.009Hakiki, N. E. (1998). Semiconducting Properties of Passive Films Formed on Stainless Steels. Journal of The Electrochemical Society, 145(11), 3821. doi:10.1149/1.1838880Olefjord, I. (1985). Surface Composition of Stainless Steels during Anodic Dissolution and Passivation Studied by ESCA. Journal of The Electrochemical Society, 132(12), 2854. doi:10.1149/1.2113683Lothongkum, G., Chaikittisilp, S., & Lothongkum, A. . (2003). XPS investigation of surface films on high Cr-Ni ferritic and austenitic stainless steels. Applied Surface Science, 218(1-4), 203-210. doi:10.1016/s0169-4332(03)00600-7Freire, L., Carmezim, M. J., Ferreira, M. G. S., & Montemor, M. F. (2010). The passive behaviour of AISI 316 in alkaline media and the effect of pH: A combined electrochemical and analytical study. Electrochimica Acta, 55(21), 6174-6181. doi:10.1016/j.electacta.2009.10.026Roberge P. R. , Corrosion Engineering. Principles and Practice, 1st. ed., McGraw-Hill, New York, NY, 2008.Wipf, D. O. (1994). Initiation and study of localized corrosion by scanning electrochemical microscopy. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 93, 251-261. doi:10.1016/0927-7757(94)02872-9Casillas, N. (1994). Pitting Corrosion of Titanium. Journal of The Electrochemical Society, 141(3), 636. doi:10.1149/1.2054783Basame, S. B., & White, H. S. (1995). Scanning electrochemical microscopy of native titanium oxide films. Mapping the potential dependence of spatially-localized electrochemical reactions. The Journal of Physical Chemistry, 99(44), 16430-16435. doi:10.1021/j100044a034Still, J. W. (1997). Breakdown of the Iron Passive Layer by Use of the Scanning Electrochemical Microscope. Journal of The Electrochemical Society, 144(8), 2657. doi:10.1149/1.1837879Zhu, Y. (1997). Scanning Electrochemical Microscopic Observation of a Precursor State to Pitting Corrosion of Stainless Steel. Journal of The Electrochemical Society, 144(3), L43. doi:10.1149/1.1837487Basame, S. B., & White, H. S. (1998). Scanning Electrochemical Microscopy:  Measurement of the Current Density at Microscopic Redox-Active Sites on Titanium. The Journal of Physical Chemistry B, 102(49), 9812-9819. doi:10.1021/jp982088xWilliams, D. E. (1998). Elucidation of a Trigger Mechanism for Pitting Corrosion of Stainless Steels Using Submicron Resolution Scanning Electrochemical and Photoelectrochemical Microscopy. Journal of The Electrochemical Society, 145(8), 2664. doi:10.1149/1.1838697Lister, T. E., & Pinhero, P. J. (2002). Scanning Electrochemical Microscopy Study of Corrosion Dynamics on Type 304 Stainless Steel. Electrochemical and Solid-State Letters, 5(11), B33. doi:10.1149/1.1510621Lister, T. E., & Pinhero, P. J. (2003). The effect of localized electric fields on the detection of dissolved sulfur species from Type 304 stainless steel using scanning electrochemical microscopy. Electrochimica Acta, 48(17), 2371-2378. doi:10.1016/s0013-4686(03)00228-7González-Garcı́a, Y., Burstein, G. ., González, S., & Souto, R. . (2004). Imaging metastable pits on austenitic stainless steel in situ at the open-circuit corrosion potential. Electrochemistry Communications, 6(7), 637-642. doi:10.1016/j.elecom.2004.04.018Souto, R. M., González-Garcı́a, Y., & González, S. (2005). In situ monitoring of electroactive species by using the scanning electrochemical microscope. Application to the investigation of degradation processes at defective coated metals. Corrosion Science, 47(12), 3312-3323. doi:10.1016/j.corsci.2005.07.005Völker, E., Inchauspe, C. G., & Calvo, E. J. (2006). Scanning electrochemical microscopy measurement of ferrous ion fluxes during localized corrosion of steel. Electrochemistry Communications, 8(1), 179-183. doi:10.1016/j.elecom.2005.10.003Gabrielli, C., Joiret, S., Keddam, M., Perrot, H., Portail, N., Rousseau, P., & Vivier, V. (2007). A SECM assisted EQCM study of iron pitting. Electrochimica Acta, 52(27), 7706-7714. doi:10.1016/j.electacta.2007.03.008Yin, Y., Niu, L., Lu, M., Guo, W., & Chen, S. (2009). In situ characterization of localized corrosion of stainless steel by scanning electrochemical microscope. Applied Surface Science, 255(22), 9193-9199. doi:10.1016/j.apsusc.2009.07.003Santana, J. J., González-Guzmán, J., Fernández-Mérida, L., González, S., & Souto, R. M. (2010). Visualization of local degradation processes in coated metals by means of scanning electrochemical microscopy in the redox competition mode. Electrochimica Acta, 55(15), 4488-4494. doi:10.1016/j.electacta.2010.02.091González-García, Y., Santana, J. J., González-Guzmán, J., Izquierdo, J., González, S., & Souto, R. M. (2010). Scanning electrochemical microscopy for the investigation of localized degradation processes in coated metals. Progress in Organic Coatings, 69(2), 110-117. doi:10.1016/j.porgcoat.2010.04.006Yuan, Y., Li, L., Wang, C., & Zhu, Y. (2010). Study of the effects of hydrogen on the pitting processes of X70 carbon steel with SECM. Electrochemistry Communications, 12(12), 1804-1807. doi:10.1016/j.elecom.2010.10.031Aouina, N., Balbaud-Célérier, F., Huet, F., Joiret, S., Perrot, H., Rouillard, F., & Vivier, V. (2011). Single pit initiation on 316L austenitic stainless steel using scanning electrochemical microscopy. Electrochimica Acta, 56(24), 8589-8596. doi:10.1016/j.electacta.2011.07.044Bard A. J. Mirkin M. V. (Eds.), Scanning Electrochemical Microscopy, 1st. ed., Marcel Dekker, New York, NJ, 2001.Kaneko, M., & Isaacs, H. . (2000). Pitting of stainless steel in bromide, chloride and bromide/chloride solutions. Corrosion Science, 42(1), 67-78. doi:10.1016/s0010-938x(99)00056-6Frankel, G. S. (1998). Pitting Corrosion of Metals. Journal of The Electrochemical Society, 145(6), 2186. doi:10.1149/1.1838615Kaneko, M., & Isaacs, H. S. (2002). Effects of molybdenum on the pitting of ferritic- and austenitic-stainless steels in bromide and chloride solutions. Corrosion Science, 44(8), 1825-1834. doi:10.1016/s0010-938x(02)00003-3Abd El Meguid, E. A., & Mahmoud, N. A. (2003). Inhibition of Bromide-Pitting Corrosion of Type 904L Stainless Steel. CORROSION, 59(2), 104-111. doi:10.5006/1.3277539Anderko, A., & Young, R. D. (2000). Model for Corrosion of Carbon Steel in Lithium Bromide Absorption Refrigeration Systems. CORROSION, 56(5), 543-555. doi:10.5006/1.3280559Chau, D. S., Wood, B. D., Berman, N. S., & Kim, K. J. (1993). Solubility of oxygen in aqueous lithium bromide using electrochemical technique. International Communications in Heat and Mass Transfer, 20(5), 643-652. doi:10.1016/0735-1933(93)90076-8Macdonald, D. D. (1992). The Point Defect Model for the Passive State. Journal of The Electrochemical Society, 139(12), 3434. doi:10.1149/1.2069096Paola, A. D. (1989). Semiconducting properties of passive films on stainless steels. Electrochimica Acta, 34(2), 203-210. doi:10.1016/0013-4686(89)87086-0Hakiki, N. E., Montemor, M. F., Ferreira, M. G. S., & da Cunha Belo, M. (2000). Semiconducting properties of thermally grown oxide films on AISI 304 stainless steel. Corrosion Science, 42(4), 687-702. doi:10.1016/s0010-938x(99)00082-7Carmezim, M. J., Simões, A. M., Figueiredo, M. O., & Da Cunha Belo, M. (2002). Electrochemical behaviour of thermally treated Cr-oxide films deposited on stainless steel. Corrosion Science, 44(3), 451-465. doi:10.1016/s0010-938x(01)00076-2Sharma S. K. , Green Corrosion Chemistry and Engineering: Opportunities and Challenges, Wiley-VCH Verlag GmbH & Co., First Edition, Germany, 2012.Venkatraman, M. S., Cole, I. S., & Emmanuel, B. (2011). Corrosion under a porous layer: A porous electrode model and its implications for self-repair. Electrochimica Acta, 56(24), 8192-8203. doi:10.1016/j.electacta.2011.06.020Thomas, S., Cole, I. S., Sridhar, M., & Birbilis, N. (2013). Revisiting zinc passivation in alkaline solutions. Electrochimica Acta, 97, 192-201. doi:10.1016/j.electacta.2013.03.008Gao, S., Dong, C., Luo, H., Xiao, K., Pan, X., & Li, X. (2013). Scanning electrochemical microscopy study on the electrochemical behavior of CrN film formed on 304 stainless steel by magnetron sputtering. Electrochimica Acta, 114, 233-241. doi:10.1016/j.electacta.2013.10.009Lu, G., Cooper, J. S., & McGinn, P. J. (2007). SECM imaging of electrocatalytic activity for oxygen reduction reaction on thin film materials. Electrochimica Acta, 52(16), 5172-5181. doi:10.1016/j.electacta.2007.02.022Song C. Zhang J. , Electrocatalytic Oxygen Reduction Reaction, in: J. Zhang (Ed.), PEM Fuel Cell Electrocatalysts and Catalyst Layers, Ch. 2, Springer, London, 2008, p. 89.Macdonald, D. D. (1999). Passivity–the key to our metals-based civilization. Pure and Applied Chemistry, 71(6), 951-978. doi:10.1351/pac199971060951Macdonald, D. D., Rifaie, M. A., & Engelhardt, G. R. (2001). New Rate Laws for the Growth and Reduction of Passive Films. Journal of The Electrochemical Society, 148(9), B343. doi:10.1149/1.1385818Macdonald, D. D. (2006). On the Existence of Our Metals-Based Civilization. Journal of The Electrochemical Society, 153(7), B213. doi:10.1149/1.2195877Marconnet, C., Wouters, Y., Miserque, F., Dagbert, C., Petit, J.-P., Galerie, A., & Féron, D. (2008). Chemical composition and electronic structure of the passive layer formed on stainless steels in a glucose-oxidase solution. Electrochimica Acta, 54(1), 123-132. doi:10.1016/j.electacta.2008.02.070Rhode, S., Kain, V., Raja, V. S., & Abraham, G. J. (2013). Factors affecting corrosion behavior of inclusion containing stainless steels: A scanning electrochemical microscopic study. Materials Characterization, 77, 109-115. doi:10.1016/j.matchar.2013.01.006Newman, R. C., & Franz, E. M. (1984). Growth and Repassivation of Single Corrosion Pits in Stainless Steel. CORROSION, 40(7), 325-330. doi:10.5006/1.3593930Simões, A. M., Bastos, A. C., Ferreira, M. G., González-García, Y., González, S., & Souto, R. M. (2007). Use of SVET and SECM to study the galvanic corrosion of an iron–zinc cell. Corrosion Science, 49(2), 726-739. doi:10.1016/j.corsci.2006.04.021Beck, T. R. (1979). Occurrence of Salt Films during Initiation and Growth of Corrosion Pits. Journal of The Electrochemical Society, 126(10), 1662. doi:10.1149/1.2128772Alkire, R. C., & Wong, K. P. (1988). The corrosion of single pits on stainless steel in acidic chloride solution. Corrosion Science, 28(4), 411-421. doi:10.1016/0010-938x(88)90060-1Bastos, A. C., Simões, A. M., González, S., González-García, Y., & Souto, R. M. (2004). Imaging concentration profiles of redox-active species in open-circuit corrosion processes with the scanning electrochemical microscope. Electrochemistry Communications, 6(11), 1212-1215. doi:10.1016/j.elecom.2004.09.022Böhni H. , Localized Corrosion of Passive Metals, in: Winston Revie R. (Ed.), Uhlig's Corrosion Handbook, 2nd ed., Ch. 10, Wiley Interscience, New York, 2000.Leiva-García, R., García-Antón, J., & Muñoz-Portero, M. J. (2010). Contribution to the elucidation of corrosion initiation through confocal laser scanning microscopy (CLSM). Corrosion Science, 52(6), 2133-2142. doi:10.1016/j.corsci.2010.02.034Laycock, N. J., & Newman, R. C. (1997). Localised dissolution kinetics, salt films and pitting potentials. Corrosion Science, 39(10-11), 1771-1790. doi:10.1016/s0010-938x(97)00049-8Moayed, M. H., & Newman, R. C. (2006). The Relationship Between Pit Chemistry and Pit Geometry Near the Critical Pitting Temperature. Journal of The Electrochemical Society, 153(8), B330. doi:10.1149/1.2210670Ernst, P., & Newman, R. . (2002). Pit growth studies in stainless steel foils. I. Introduction and pit growth kinetics. Corrosion Science, 44(5), 927-941. doi:10.1016/s0010-938x(01)00133-0Ernst, P., Laycock, N. J., Moayed, M. H., & Newman, R. C. (1997). The mechanism of lacy cover formation in pitting. Corrosion Science, 39(6), 1133-1136. doi:10.1016/s0010-938x(97)00043-7Sun, D., Jiang, Y., Tang, Y., Xiang, Q., Zhong, C., Liao, J., & Li, J. (2009). Pitting corrosion behavior of stainless steel in ultrasonic cell. Electrochimica Acta, 54(5), 1558-1563. doi:10.1016/j.electacta.2008.09.056Ren, J., & Zuo, Y. (2005). The growth mechanism of pits in NaCl solution under anodic films on aluminum. Surface and Coatings Technology, 191(2-3), 311-316. doi:10.1016/j.surfcoat.2004.04.05

Precise multimodal optical control of neural ensemble activity.

Understanding brain function requires technologies that can control the activity of large populations of neurons with high fidelity in space and time. We developed a multiphoton holographic approach to activate or suppress the activity of ensembles of cortical neurons with cellular resolution and sub-millisecond precision. Since existing opsins were inadequate, we engineered new soma-targeted (ST) optogenetic tools, ST-ChroME and IRES-ST-eGtACR1, optimized for multiphoton activation and suppression. Employing a three-dimensional all-optical read-write interface, we demonstrate the ability to simultaneously photostimulate up to 50 neurons distributed in three dimensions in a 550 × 550 × 100-µm3 volume of brain tissue. This approach allows the synthesis and editing of complex neural activity patterns needed to gain insight into the principles of neural codes

SDSSJ143244.91+301435.3: a link between radio-loud narrow-line Seyfert 1 galaxies and compact steep-spectrum radio sources?

We present SDSSJ143244.91+301435.3, a new case of radio-loud narrow line Seyfert 1 (RL NLS1) with a relatively high radio power (P1.4GHz=2.1x10^25 W Hz^-1) and large radioloudness parameter (R1.4=600+/-100). The radio source is compact with a linear size below ~1.4 kpc but, contrary to most of the RL NLS1 discovered so far with such a high R1.4, its radio spectrum is very steep (alpha=0.93) and not supporting a 'blazar-like' nature. Both the small mass of the central super-massive black-hole and the high accretion rate relative to the Eddington limit estimated for this object (3.2x10^7 Msun and 0.27, respectively, with a formal error of ~0.4 dex on both quantities) are typical of the class of NLS1. Through a modeling of the spectral energy distribution of the source we have found that the galaxy hosting SDSSJ143244.91+301435.3 is undergoing a quite intense star-formation (SFR=50 Msun y^-1) which, however, is expected to contribute only marginally (~1 per cent) to the observed radio emission. The radio properties of SDSSJ143244.91+301435.3 are remarkably similar to those of compact steep spectrum (CSS) radio sources, a class of AGN mostly composed by young radio galaxies. This may suggest a direct link between these two classes of AGN, with the CSS sources possibly representing the misaligned version (the so-called parent population) of RL NLS1 showing blazar characteristics.Comment: 14 pages, 7 figures, 4 tables, accepted for publication in MNRA

A Neural-Astrocytic Network Architecture: Astrocytic calcium waves modulate synchronous neuronal activity

Understanding the role of astrocytes in brain computation is a nascent challenge, promising immense rewards, in terms of new neurobiological knowledge that can be translated into artificial intelligence. In our ongoing effort to identify principles endow-ing the astrocyte with unique functions in brain computation, and translate them into neural-astrocytic networks (NANs), we propose a biophysically realistic model of an astrocyte that preserves the experimentally observed spatial allocation of its distinct subcellular compartments. We show how our model may encode, and modu-late, the extent of synchronous neural activity via calcium waves that propagate intracellularly across the astrocytic compartments. This relationship between neural activity and astrocytic calcium waves has long been speculated but it is still lacking a mechanistic explanation. Our model suggests an astrocytic "calcium cascade" mechanism for neuronal synchronization, which may empower NANs by imposing periodic neural modulation known to reduce coding errors. By expanding our notions of information processing in astrocytes, our work aims to solidify a computational role for non-neuronal cells and incorporate them into artificial networks.Comment: International Conference on Neuromorphic Systems (ICONS) 201