Sensors based on upconverting nanoparticles for the detection of RNA/DNA oligolnucleotides

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Farmacia, Departamento de Química en Ciencias Farmacéuticas, leída el 04-07-2019Depto. de Química en Ciencias FarmacéuticasFac. de FarmaciaTRUEunpu

Synergistic effect of magnetite nanoparticles and carbon nanofibres in electromagnetic absorbing composites

Epoxy composites with different amounts of magnetite nanoparticles, carbon nanofibres (CNF) and magnetite-decorated CNF were prepared and characterized. A simple method for the magnetite CNF decoration was developed by adsorbing preformed oleic acid capped-magnetite nanoparticles over the CNF surface. A synergy between magnetite nanoparticles and CNF was found to have crucial effects in the electromagnetic shielding efficiency of the prepared materials. This effect has been analysed by their electrical conductivity in terms of percolation theory and complex permittivity at high frequencies. Electromagnetic shielding mechanisms (reflection, absorption and transmission) were individually studied in the 1-18 GHz range. Results show that decoration of CNF with magnetite, notably increases permittivity and high-frequency AC conductivity and enhances the electromagnetic shielding efficiency up to around 20 dB at high frequencies. It is proposed that interfacial polarization adds an additional dissipation mechanism that may be responsible for the observed electromagnetic shielding enhancement.This work was supported by grants Nacopan (MAT2007-31173-E) and Nanomod (MAT2010-17091) from the Spanish Ministerio de Ciencia e Innovación

Prevalence and Antimicrobial Susceptibility of Potentially Pathogenic Bacteria and Fungi Isolated from Public Parks of Bogotá, Colombia

Regular interactions of humans with their environment, animals and different microorganisms as part of everyday routine can cause several infections or diseases that can become a public health problem if these are not properly controlled. It is necessary to identify potentially pathogenic bacteria (with its antimicrobial resistance) and fungi, and their prevalence in public parks in Bogotá city. Four parks were evaluated, where samples were taken from dog’s feces and hair, recreational items and environmental material, to perform the microorganism’s isolations. The higher prevalence percentages in each sort of sample were for Escherichia coli, Staphylococcus epidermidis, Staphylococcus aureus, Rahnella aquatilis, Penicillium spp, Cladosporium spp. and Mucor spp. and there were pathogenic species like Salmonella enteritidis and Klebsiella pneumoniae. We report a strain of S. aureus with intermediate resistance to vancomycin (VISA) found in recreational items. The higher rates of antibiotics resistance like ampicillin and trimethoprim were found in the isolations from dog’s feces. Some species or genera reported are considerated as opportunistic pathogens; however, these and the pathogenic species reported represent a threat to human health and this is why it is essential to have a personal hygiene plan after stay at a park.Regular interactions of humans with their environment, animals and different microorganisms as part of everyday routine can cause several infections or diseases that can become a public health problem if these are not properly controlled. It is necessary to identify potentially pathogenic bacteria (with its antimicrobial resistance) and fungi, and their prevalence in public parks in Bogotá city. Four parks were evaluated, where samples were taken from dog’s feces and hair, recreational items and environmental material, to perform the microorganism’s isolations. The higher prevalence percentages in each sort of sample were for Escherichia coli, Staphylococcus epidermidis, Staphylococcus aureus, Rahnella aquatilis, Penicillium spp, Cladosporium spp. and Mucor spp. and there were pathogenic species like Salmonella enteritidis and Klebsiella pneumoniae. We report a strain of S. aureus with intermediate resistance to vancomycin (VISA) found in recreational items. The higher rates of antibiotics resistance like ampicillin and trimethoprim were found in the isolations from dog’s feces. Some species or genera reported are considerated as opportunistic pathogens; however, these and the pathogenic species reported represent a threat to human health and this is why it is essential to have a personal hygiene plan after stay at a park

Performance Evaluation of a VLC Transmitter Based on the Split of the Power

IEEE Applied Power Electronics Conference and Exposition, San Antonio, (Estados Unidos de Norteamérica), marzo de 2018Visible Light Communication (VLC) has gained relevance during last years. It consists in using High-Brightness LEDs (HB-LEDs) both for lighting and for transmitting information changing the light intensity rapidly. However, there are some bottlenecks that are slowing down the deployment of this technology. One of the most important problems is that the HB-LED drivers proposed for addressing high data rates in VLC achieve poor power efficiency. Since these HB-LED drivers must be able to reproduce fast current waveforms, the use of Linear Power Amplifiers (LPAs) has been adopted, which clearly damage the power efficiency of HB-LED lighting. In order to alleviate this problem, a HB-LED driver made up of two DC-DC power converters is presented in this work. One of them is responsible for performing the communication functionality by operating at high switching frequency (10 MHz), whereas the second one fulfills the illumination functionality by ensuring a certain biasing point. The split of the power allows to minimize the power delivered by the fast-response DC-DC power converter. Thus, the efficiency can be maximized for scenarios with changing conditions (i.e., mobile transmitter and/or receiver, presence of mobile obstacles, etc.). In this sense, how the lighting level and the communication signal power affect both the power efficiency and the communication efficiency is deeply analyzed. The implemented prototype achieves an overall efficiency around 90%. In addition, the proposed VLC transmitter is able to reproduce a wide range of digital modulation schemes, including Orthogonal Frequency Division Multiplexing (OFDM

Reproducing single-carrier digital modulation schemes for VLC by controlling the first switching harmonic of the dc-dc power converter output voltage ripple

A DC-DC power converter based on a two-phase synchronous buck converter that reproduces single-carrier digital modulation schemes by controlling the first switching harmonic of the output voltage ripple is presented in this work. The DC-DC power converter carries out both the lighting and the transmission functionalities of Visible Light Communication (VLC) transmitters. Control of both the amplitude and the phase of sinusoidal currents injected towards High-Brightness LEDs (HB-LEDs) enables the use of efficient modulation schemes such as Quadrature Amplitude Modulation (QAM), Carrier-less Amplitude and Phase modulation (CAP), Amplitude-Shift Keying (ASK) and Phase-Shift Keying (PSK). These modulation schemes achieve higher spectral efficiency (i.e. more data can be transmitted using the same bandwidth) than previously proposed modulation schemes performed by VLC transmitters based on the use of DC-DC power converters. To the author's knowledge, the ratio between the bit rate achieved and the switching frequency of the DC-DC power converter presented in this paper is the highest that can be found in literatur

LINUX NETHSERVER: SERVICIOS DE INFRAESTRUCTURA TI

Este artículo presenta una guía paso a paso para la instalación y configuración de GNU/Linux NethServer, enfocándose en la implementación de los servicios DHCP Server, DNS Server y un Controlador de Dominio. Se usará una maquina virtual que permitirá generar la evidencia de la configuración e instalación, así, como la implementación de los servicios. NethServer es una distribución de Linux basada en CentOS, que ofrece una interfaz de administración web intuitiva y fácil de usar [1]. El artículo arropa la instalación inicial de NethServer, la configuración básica del sistema y los pasos para añadir y configurar los servicios DHCP Server, DNS Server y el Controlador de Dominio. Este artículo es una excelente referencia para aquellos que deseen implementar una solución de servidor de red basada en GNU/Linux utilizando NethServer.This article presents a step-by-step guide for the installation and configuration of GNU/Linux NethServer, focusing on the implementation of DHCP Server, DNS Server and a Domain Controller services. A virtual machine will be used to generate evidence of the configuration and installation, as well as the implementation of their services. NethServer is a CentOS-based Linux distribution, offering an intuitive and easy to use web administration interface [1]. The article completes the initial installation of NethServer, basic system configuration, and steps to add and configure DHCP Server, DNS Server, and Domain Controller services. This article is an excellent reference for everyone want to implement a GNU/Linux-based network server solution using NethServer

LINUX NETHSERVER: SERVICIOS DE INFRAESTRUCTURA TI

Este artículo presenta una guía paso a paso para la instalación y configuración de GNU/Linux NethServer, enfocándose en la implementación de los servicios DHCP Server, DNS Server y un Controlador de Dominio. Se usará una maquina virtual que permitirá generar la evidencia de la configuración e instalación, así, como la implementación de los servicios. NethServer es una distribución de Linux basada en CentOS, que ofrece una interfaz de administración web intuitiva y fácil de usar [1]. El artículo arropa la instalación inicial de NethServer, la configuración básica del sistema y los pasos para añadir y configurar los servicios DHCP Server, DNS Server y el Controlador de Dominio. Este artículo es una excelente referencia para aquellos que deseen implementar una solución de servidor de red basada en GNU/Linux utilizando NethServerThe article presents a step-by-step guide for the installation and configuration of GNU/Linux NethServer, focusing on the implementation of DHCP Server, DNS Server and a Domain Controller services. A virtual machine will be used to generate evidence of the configuration and installation, as well as the implementation of their services. NethServer is a Linux distribution supported on CentOS, offering an intuitive and easy to use web administration interface [1]. The article shows the initial installation of NethServer, basic system configuration, and steps to add and configure DHCP Server, DNS Server, and Domain Controller services. This article is an excellent reference for everyone want to implement a GNU/Linux-based network server solution using NethServer