1,081 research outputs found

    Neuraminidase-activated microglia compromise the viability of ependymocytes

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    Neuraminidase (NA) is a sialidase present in the envelope/wall of some virus/bacteria responsible for brain infections, such as flu, mumps or meningitis. The intracerebroventricular injection of NA in the rat brain provokes ependymal detachment and death, and an acute inflammatory process. Although inflammation reverses, ependymal lining is not regenerated. Complement system activation within the CSF contributes to ependymal damage, but is not the only cause (Granados-Duran et al, 2016). Here we aimed to investigate if microglial activation might also play a role. For this purpose we used pure isolated ependymocytes (Grondona et al, 2013) and ventricular wall explants, which were co-cultured with microglial cells, both in basal conditions and with agents that induce microglial activation: NA, LPS, or Pam3CSK4 (synthetic lipopeptide). The viability of the ependymal cells was assessed by trypan blue exclusion. The viability of isolated ependymocytes was reduced when NA or LPS were added to the culture, compared to controls without additives. In the absence of microglia, NA or LPS did not compromise viability significantly, indicating that microglia was involved in ependymocytes death. The addition of NA to cultured explants reduced ependymocytes viability only when microglial cells were present in the culture; a similar reduction was observed when LPS or Pam3CSK4 were added. Conversely, explants cultured in the absence of microglia did not suffer a significant decrease in ependymocytes viability upon NA addition to the medium. We hypothesized that cytokines released by activated microglia, such as IL1β or TNFα, could mediate ependymocytes death. RT-PCR performed in RNA obtained from pure ependymocytes confirmed the presence of IL1β and TNFα receptors in ependymal cells. Nevertheless further experiments are required to confirm this hypothesis. We conclude that microglia activated by NA mediates, at least in part, ependymal cell death, what might be relevant for neuroinflammatory diseases mediated by NA bearing virus/bacteria.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    0.6-V-VIN 7.0-nA-IQ 0.75-mA-IL CMOS Capacitor-Less LDO for Low-Voltage Micro-Energy-Harvested Supplies

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    A capacitor-less (CL) low-dropout (LDO) regulator suitable to be incorporated in an on-chip system with low-voltage micro-energy-harvested supply, is proposed in this contribution. The differential input stage of the error amplifier includes bulk-driven MOS transistors, thus providing the LDO with an output voltage range that extends from the negative rail up to a level very close to the input voltage without the need of using a resistive feedback network. The circuit parameters relying on the feedback factor, , are maximized thanks to the use of a unitary value for this parameter. The CL-LDO has been designed and fabricated in standard 180-nm CMOS technology and optimized to operate with an input voltage equal to 0.6 V and a reference level of 0.5 V. The experimental characterization of the fabricated prototypes shows that, under these operating conditions, the LDO is able to deliver a load current above 0.75 mA with a total quiescent current of only 7.0 nA. Furthermore, the proposed voltage regulator is able to operate from input voltages as low as 0.4 V, delivering in this case a maximum load current of 30 μA.RTI2018- 095994-B-I00 ED431G-2019/04 GRC2021/48 IB18079S

    The Principles of Gold-Catalyzed Molecular Gymnastics

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    L'or(I) dirigeix el contorsionisme molecular mitjançant reaccions intramoleculars i intermoleculars d'enins per mitjà d'intermedis ciclopropil o carbens altament distorsionats. La síntesi de productes naturals com (+)-orienalol F i (-)-englerin A mostra l'estat d'art de la catàlisi de l'or(I) per a construir complexitat molecular.Gold(I) orchestrates molecular gymnastics by intraand intermolecular reaction of enymes via highly distorted cyclopropyl gold carbenes as intermediates. The synthesis of natural products such as (+)-orientalol F and (−)-englerin A illustrates the state of the art of gold (I) catalysis for the buildup of molecular complexity

    Para asombrarse y aprender

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    Este trabajo presenta la fundamentación, diseño y resultados de un proyecto realizado en el marco de un programa institucional en la UNAM, relacionado con la innovación de la enseñanza experimental. Como producto de este proyecto se elaboró un libro con 30 experimentos de aula dirigidos a profesores de los niveles bachillerato y universitario. Los experimentos elaborados presentan propuestas experimentales novedosas que nos permitan reconceptualizar y diversificar el trabajo práctico

    The CIAO Multi-Dialect Compiler and System: An Experimentation Workbench for Future (C)LP Systems

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    CIAO is an advanced programming environment supporting Logic and Constraint programming. It offers a simple concurrent kernel on top of which declarative and non-declarative extensions are added via librarles. Librarles are available for supporting the ISOProlog standard, several constraint domains, functional and higher order programming, concurrent and distributed programming, internet programming, and others. The source language allows declaring properties of predicates via assertions, including types and modes. Such properties are checked at compile-time or at run-time. The compiler and system architecture are designed to natively support modular global analysis, with the two objectives of proving properties in assertions and performing program optimizations, including transparently exploiting parallelism in programs. The purpose of this paper is to report on recent progress made in the context of the CIAO system, with special emphasis on the capabilities of the compiler, the techniques used for supporting such capabilities, and the results in the áreas of program analysis and transformation already obtained with the system

    An 11 mA Capacitor-Less LDO With 3.08 nA Quiescent Current and SSF-Based Adaptive Biasing

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    This brief presents an ultra-low power low-dropout (LDO) regulator with an experimental total quiescent current consumption of only 3.08 nA. The circuit is designed to operate with a load current in the range 0 - 11 mA. A novel adaptive biasing scheme based on a super source follower (SSF) structure is proposed, which measures the absolute voltage difference between the two inputs of the LDO’s error amplifier and modifies the biasing current accordingly. Thus, the transient response of the regulator is improved by counteracting the effect of using such a low bias current. The proposed LDO has been fabricated in a standard CMOS 180 nm process and the experimental characterization showed an outstanding performance in terms of maximum load current over quiescent current consumption ratio.S

    Inglés técnico naval

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    El objetivo del presente libro es ofrecer a profesores, alumnos y profesionales en general del mundo de la industria y la navegación, la posibilidad de disponer de un texto de trabajo y consulta sobre el inglés técnico naval. El libro se divide en 21 unidades, que versan cada una de ellas sobre diferentes aspectos relacionados con el buque: materiales y procedimientos usados en su construcción, tipos de buques, partes principales del buque, estabilidad, etc.360 pág
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