Dendritic neurotransmitter release and its modulation in accessory olfactory bulb circuits

Dendrites are classically regarded as the brain's "listeners," while neuronal output is thought to be the exclusive privilege of the axon. Although we now appreciate the complexity of dendritic integration, the role of dendrites as output structures has received less attention. This is becoming an increasingly important topic, as the list of cell types with release competent dendrites continues to grow. One boon of coupling dendritic activity to dendritic release is that outputs from a single neuron - typically thought to occur from fixed sites with stereotyped dynamics - may occur for signals of varying spatial extent, timecourse, and release efficacy. In essence, dendritic output may "inherit" the same diversity characteristic of events in excitable dendrites. Here I studied dendritic transmitter output and its modulation in cells of the accessory olfactory bulb - a CNS structure critical for processing species-specific chemical signals called pheromones. Because of the stereotypy of its inputs, the prevalence of dendritic transmitter release from its cells, and its well-defined outputs, the AOB offers a superb model system for studying the integrative and output properties of dendrites. I first characterized basic excitable properties of the apical dendrites of mitral cells (the principal AOB neurons), and observed that they conduct non-decremental action potentials (APs). In addition to APs, these dendrites were also found to support compartmentalized, synaptically-evoked calcium spikes. Both APs and local spikes were triggers of dendritic glutamate release and feedback inhibition, suggesting that neuronal output can be flexibly routed to particular populations of postysynaptic cells. I next asked whether the relative efficacy of particular dendritic events as triggers of transmitter release can be altered, as this could provide an additional level of control over single neuron output. I found that metabotropic glutamate receptors (mGluRs) play a key role in controlling dendritic output from AOB mitral cells and an obligatory role in concomitant feedback inhibition. This work culminates with the demonstration of a new principle of neuronal signaling: the ability of mGluRs to gate a transition between phasic and tonic dendritic transmitter release. Taken in total, these results extend our understanding of how the outputs from single neurons are controlled

A Dual Nanostructured Approach to SERS Amenable to Large-Scale Production

A SERS device was made using a dual-nanostructured surface comprised of silver nanoparticle and silver nanowires. The ability of each nanostructure to produce a uniform surface was characterized and the surface-enhanced Raman scattering (SERS) response of the resulting surfaces were examined using the reporter molecule 4-aminothiolphenol (ATP) and a 638 nm excitation laser. A synthetic method was developed to produce silver nanowires with lengths of ~20 μm and diameters of ~100 nm with a narrow size distribution. The method utilized a simple, one-pot synthesis that is amenable to large-scale production. A selective precipitation method was used to the isolate the ~200 aspect ratio silver nanowires in a high purity. The wires were Mayer rod coated onto glass slides to produce uniform surfaces with ease. The SERS response was found to be highly variable depending on the sampled location. An enhancement factor of 2.2x105 was tentatively assigned using the 1600 cm-1 peak of ATP. The silver complex μ-oxolato-bis(ethylenediaminesilver(I)) was synthesized as reported in the literature. The aqueous solution of the complex was thermally decomposed to produce SERS-active silver surfaces on glass slides. The silver complex was unable to generate a uniform surface coating without the use of additives. By dropcasting the complex at the decomposition temperature, surfaces were generated exhibiting ~75 nm, spherical nanoparticles. The surface was found to be SERS-active, however the poor processing characteristics of the complex prevent its applicability to large-scale device production. Silver nanowire surfaces were used as substrates to Mayer rod coat the silver complex uniformly without the use of additives. This provided the proof-of-concept that the dual-nanostructured surface is amenable to large scale production through the use of roll-to-roll printing. A dual-nanostructured surface was produced by dropcasting the complex on silver nanowire surfaces to mimic the quality of surface achievable by an industrial production line. The dual-nanostructured surface produced a spatially consistent SERS response and an enhancement factor of 4.3x105 was tentatively assigned using the 1600 cm-1 peak of ATP

Fabrication and Comprehensive Modeling of Ion-Exchanged Bragg Opitcal Add-Drop Multiplexers

Optical add–drop multiplexers (OADMs) based on asymmetric Y branches and tilted gratings offer excellent-performance in wavelength-division multiplexed systems. To simplify waveguide fabrication, ion-exchange techniques appear to be an important option in photosensitive glasses. Optimum OADM performance depends on how accurately the waveguide fabrication process and tilted Bragg grating operation are understood and modeled. Results from fabrication and comprehensive modeling are compared for ion-exchange processes that use different angles of the tilted grating. The transmission and reflection spectra for the fabricated and simulated OADMs show excellent agreement. The OADM’s performance is evaluated in terms of the measured characteristics of the Y branches and tilted gratings

Evidence of Particle Acceleration in the Superbubble 30 Doradus C with NuSTAR

We present evidence of diffuse, non-thermal X-ray emission from the superbubble 30 Doradus C (30 Dor C) using hard X-ray images and spectra from NuSTAR observations. For this analysis, we utilize data from a 200 ks targeted observation of 30 Dor C as well as 2.8 Ms of serendipitous off-axis observations from the monitoring of nearby SN 1987A. The complete shell of 30 Dor C is detected up to 20 keV, and the young supernova remnant MCSNR J0536-6913 in the southeast of 30 Dor C is not detected above 8 keV. Additionally, six point sources identified in previous Chandra and XMM-Newton investigations have hard X-ray emission coincident with their locations. Joint spectral fits to the NuSTAR and XMM-Newton spectra across the 30 Dor C shell confirm the non-thermal nature of the diffuse emission. Given the best-fit rolloff frequencies of the X-ray spectra, we find maximum electron energies of 70-110 TeV (assuming a B-field strength of 4$\mu$G), suggesting 30 Dor C is accelerating particles. Particles are either accelerated via diffusive shock acceleration at locations where the shocks have not stalled behind the H$\alpha$ shell, or cosmic-rays are accelerated through repeated acceleration of low-energy particles via turbulence and magnetohydrodynamic waves in the bubble's interior.Comment: 14 pages, 8 figures, ApJ, in pres

A Dual Nanostructured Approach to SERS Substrates Amenable to Large-Scale Production

Surface enhanced Raman spectroscopy (SERS), although popular in research, has not yet been adopted in industrial applications. This is largely due to the challenge of manufacturing cost-effective, reproducible SERS substrates in volume that can be read by a compact reader for practical deployment in the field. Here we demonstrate and characterize a new dual-nanostructured SERS substrate approach that could be amenable to large-scale production. This dual-nanostructured surface combines long-range ordering of silver nanowires (AgNWs) with dense non-ordered decoration via silver nanoparticles (AgNPs) to improve on the SERS response characteristics of the individual structures, using fabrication methods that could be scaled for deposition via roll-to-roll Mayer rod coating. Characterization of the substrates\u27 SERS response using 638 nm Raman spectroscopy and ATP as the reporter molecule found the dual-nanostructured SERS substrate to offer both greater spatial uniformity and a consistently higher SERS enhancement factor (EF) than the nanowires alone

Hybrid Filter Membrane

Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of dust particles on the filter surface and to facilitate dust removal with pulse or back airflow

Obtaining a hydrographic basin through the use of an "Arcgis" commercial software and the use of a "Saga" free software. Case study municipality of Porcesito, Antioquia

La ubicación geográfica de Colombia, las condiciones geomorfológicas y de terreno, junto con la abundante oferta hídrica, hacen del país, un territorio idóneo para realizar estudios multicriterio y de análisis variado, para la toma de decisiones en proyectos ambientales y de impacto antropomórfico de corto, mediano y largo plazo. Debido al avance tecnológico tanto en software licenciados de diferentes costos como lo es Arcgis y también de software libre de codificación gratuita y abierta para instalar desde internet, los análisis mencionados anteriormente pueden ser modelados, plasmados de forma dinámica en una amplia oferta de los mismos. Como profesionales en geomática, con el criterio teórico y práctico surge la necesidad de aplicar metodologías de comparación, que cumplan criterios normativos y técnicos, precisando la forma de tratar la información espacial, teniendo en cuenta como obtener el software, instalación y manejo, para así dar un concepto de los mismo dependiendo del escenario de los proyectos a trabajar y el objetivo por el cual se utilizó alguno de los programas. Para hacer la comparación aplicada del resultado de análisis hidrográfico de cuencas obtenido con los dos software, se implementó para una zona del municipio de Porcesito del departamento de Antioquia, soportado con datos de la zona como lo son los modelos digitales de elevación y cartografía base.The geographic location of Colombia, the geomorphological and terrain conditions, together with the abundant water supply, make the country an ideal place to carry out multi-criteria and varied analysis studies for decision-making in environmental projects with short anthropomorphic impact, medium and long term. Due to the technological progress of licensed software of different costs, Arcgis and also offers free and open coding software to be installed from the internet, the analyzes mentioned above can be modeled, dynamically expressed in a wide range of them. As professionals in geomatics, with the theoretical and practical criteria arises the need to apply comparison methodologies, which comply with normative and technical criteria, specifying the way to treat spatial information, taking into account how to obtain the software, installation and management, in order to To give a concept of the same depending on the scenario of the projects to work and the objective for which one of the programs was used. In order to make the applied comparison of the result of hydrographic analysis of basins obtained with the two software, it was implemented for an area of the municipality of Porcesito of the department of Antioquia, supported with data of the zone as they are the digital models of elevation and base cartography

Effects of form and motion on judgments of social robots' animacy, likability, trustworthiness and unpleasantness

One of robot designers' main goals is to make robots as sociable as possible. Aside from improving robots' actual social functions, a great deal of effort is devoted to making them appear lifelike. This is often achieved by endowing the robot with an anthropomorphic body. However, psychological research on the perception of animacy suggests another crucial factor that might also contribute to attributions of animacy: movement characteristics. In the current study, we investigated how the combination of bodily appearance and movement characteristics of a robot can alter people's attributions of animacy, likability, trustworthiness, and unpleasantness. Participants played games of Tic-Tac-Toe against a robot which (1) either possessed a human form or did not, and (2) either exhibited smooth, lifelike movement or did not. Naturalistic motion was judged to be more animate than mechanical motion, but only when the robot resembled a human form. Naturalistic motion improved likeability regardless of the robot's appearance. Finally, a robot with a human form was rated as more disturbing when it moved naturalistically. Robot designers should be aware that movement characteristics play an important role in promoting robots' apparent animacy.This work was partially supported by the Spanish Government through the project call "Aplicaciones de los robots sociales", DPI2011-26980 from the Spanish Ministry of Economy and Competitiveness. Álvaro Castro-González was partially supported by a grant from Universidad Carlos III de Madrid