Rapid Prototyping for Evaluating Vehicular Communications

[Abstract] This Thesis details the different elements of a rapid prototyping system able to implement and evaluate vehicular communications fast, according to the continuously evolving requirements of the industry. The system is basically composed of a testbed and a channel emulator, which allow evaluating communication transceivers in realistic vehicular scenarios. Two different testbeds are introduced: a generic 2x2 system and a vehicular platform. The former is used to compare and study space-time block coding (STBC) transmissions at 2.4 GHz over different indoor channels. The latter makes use of software transceivers whose performance is evaluated when they work under artificial high-speed Rayleigh-fading scenarios. To show the capabilities of both platforms, three software transceivers have been developed following the specifications for the physical layers of the standards IEEE 802.11p, IEEE 802.11a and IEEE 802.16e (Mobile WiMAX). The present work details the different elements that make up each transceiver and indicates how to connect them to the rest of the system to perform evaluation measurements. Finally, single-antenna and multi-antenna performances are measured thanks to the design and implementation of three FPGA-based channel emulators that are able to recreate up to seven different vehicular scenarios that include urban canyons, suburban areas and highways[Resumo] A presente Tese detalla os elementos necesarios para constituir un sistema basado en prototipado rápido capaz de levar a cabo e avaliar comunicacións vehiculares. O hardware do sistema está composto básicamente por unha plataforma de probas (testbed) e un emulador de canal, os cales permiten avaliar o rendemento de transceptores inartiamicos recreando diferentes escenarios vehiculares. Inicialmente, este traballo céntrase na descripción do hardware do sistema, detallando a construcción e proba dunha plataforma multi-antena e un testebed vehicular. Estos sistemas permitiron, respectivamente, estudar o comportamento de códigos STBC (space-time block codes) en interiores e medir o rendemento de tranceptores software ao traballar a distintas velocidades vehiculares en canais con desvaecemento Rayleigh. Tres transceptores software foron creados seguindo as especificacións das capas físicas dos estándares IEEE 802.11p, IEEE 802.11a e IEEE 802.16e (Mobile WiMAX). Este traballo detalla os diferentes componentes de cada transceptor, indicando cómo conectalos ao resto do sistema para realizar a avaliacition do seu rendemento. Dita avaliación realizouse coa axuda de tres emuladores de canal basados en tecnoloxía FPGA (Field Programmable Gate Array), os cales son capaces de recrear ata sete escenarios vehiculares distintos, incluindo cañóns urbanos, zonas suburbanas e autopistas.[Resumen] La presente Tesis detalla los elementos necesarios para constituir un sistema basado en prototipado rtiapido capaz de llevar a cabo y evaluar comunicaciones vehiculares. El hardware del sistema está compuesto por una plataforma de pruebas (testbed) y un emulador de canal, los cuales permiten evaluar el rendimiento de transceptores inaltiambricos recreando diferentes escenarios vehiculares. Inicialmente, este trabajo se centra en la descripcition del hardware del sistema, detallando la construccition y prueba de una plataforma multi-antena y un testebed vehicular. Estos sistemas han permitido, respectivamente, estudiar el comportamiento de ctiodigos STBC (space-time block codes) en interiores y medir el rendimiento en canal con desvanecimiento Rayleigh de tranceptores software a distintas velocidades vehiculares. Tres transceptores software han sido creados siguiendo las especificaciones de las capas físicas de los estandares IEEE 802.11p, IEEE 802.11a e IEEE 802.16e (Mobile WiMAX). Este trabajo detalla los diferentes componentes de cada transceptor, indicando ctiomo conectarlos al resto del sistema para realizar la evaluacition de su rendimiento. Dicha evaluacition se realiztio con la ayuda de tres emuladores de canal basados en FPGAs (Field Programmable Gate Array), los cuales son capaces de recrear comunicaciones multi-antena en hasta siete escenarios vehiculares distintos, incluyendo cañones urbanos, zonas suburbanas y autopistas

Enzyme-Based Microfluidic Chip Coupled to Graphene Electrodes for the Detection of D‑Amino Acid Enantiomer-Biomarkers

An electrochemical microfluidic strategy for the separation and enantiomeric detection of d-methionine (d-Met) and d-leucine (d-Leu) is presented. These D-amino acids (D-AAs) act as biomarkers involved in relevant diseases caused by <i>Vibrio cholerae</i>. On a single layout microfluidic chip (MC), highly compatible with extremely low biological sample consumption, the strategy allowed the controlled microfluidic D-AA separation and the specific reaction between D-amino acid oxidase (DAAO) and each D-AA biomarker avoiding the use of additives (i.e., cyclodextrins) for enantiomeric separation as well as any covalent immobilization of the enzyme into the wall channels or on the electrode surface such as in the biosensor-based approaches. Hybrid polymer/graphene-based electrodes were end-channel coupled to the microfluidic system to improve the analytical performance. d-Met and d-Leu were successfully detected becoming this proof-of-the-concept a promising principle for the development of point-of-care (POC) devices for <i>in situ</i> screening of <i>V. cholerae</i> related diseases

Clinical and Virological Efficacy of Etravirine Plus Two Active Nucleos(t)ide Analogs in an Heterogeneous HIV-Infected Population

Etravirine (ETV) is recommended in combination with a boosted protease inhibitor plus an optimized background regimen for salvage therapy, but there is limited experience with its use in combination with two nucleos(t)ide reverse-transcriptase inhibitors (NRTIs). This multicenter study aimed to assess the efficacy of this combination in two scenarios: group A) subjects without virologic failure on or no experience with non-nucleoside reverse-transcriptase inhibitors (NNRTIs) switched due to adverse events and group B) subjects switched after a virologic failure on an efavirenz- or nevirapine-based regimen. The primary endpoint was efficacy at 52 weeks analysed by intention-to-treat. Virologic failure was defined as the inability to suppress plasma HIV-RNA to,50 copies/mL after 24 weeks on treatment, or a confirmed viral load.200 copies/mL in patients who had previously achieved a viral suppression or had an undetectable viral load at inclusion. Two hundred eighty seven patients were included. Treatment efficacy rates in group A and B were 88.0 % (CI95, 83.9–92.1%) and 77.4 % (CI95

Identificación de daños en el arbolado de tres parques del Distrito Federal

Los indicadores de salud permiten diagnosticar el estado fitosanitario y la evolución de los daños en los bosques; a nivel del arbolado, miden el tipo, la localización y la severidad que le provocan enfermedades, insectos, tormentas y actividades humanas. Para evaluar su efectividad en el área urbana, se aplicó la metodología utilizada por el Inventario Nacional Forestal y de Suelos de México y por el Forest Inventory Analysis con adaptaciones especiales. Los sitios de muestreo se establecieron dentro de los parques Alameda Norte, Alameda Oriente y Alameda Sur en el Distrito Federal. Se realizaron tres muestreos durante primavera-otoño (mayo a octubre 201) y uno en invierno (noviembre 201 a enero 2012). Se estimaron las distribuciones de frecuencia, el índice de severidad de daño (ISD) en cada parque y su ubicación dentro de cada uno. El principal problema identificado en los tres lugares fue el vandalismo. Tanto en la Alameda Norte como en la Alameda Sur se registró un número elevado de árboles muertos en pie. Las actividades antropogénicas y el escaso mantenimiento se relacionaron con las afectaciones detectadas más importantes, independientemente de la diversidad de especies. Los valores altos de ISD se observaron en árboles invadidos por muérdago, mientras que los más bajos, en árboles con señales de vandalismo

Carbon–Nitrogen Bond Construction and Carbon–Oxygen Double Bond Cleavage on a Molecular Titanium Oxonitride: A Combined Experimental and Computational Study

New carbon–nitrogen bonds were formed on addition of isocyanide and ketone reagents to the oxonitride species [{Ti­(η⁵-C₅Me₅)­(μ-O)}₃(μ₃-N)] (<b>1</b>). Reaction of <b>1</b> with XylNC (Xyl = 2,6-Me₂C₆H₃) in a 1:3 molar ratio at room temperature leads to compound [{Ti­(η⁵-C₅Me₅)­(μ-O)}₃­(μ-XylNCCNXyl)­(NCNXyl)] (<b>2</b>), after the addition of the nitrido group to one coordinated isocyanide and the carbon–carbon coupling of the other two isocyanide molecules have taken place. Thermolysis of <b>2</b> gives [{Ti­(η⁵-C₅Me₅)­(μ-O)}₃­(XylNCNXyl)­(CN)] (<b>3</b>) where the heterocumulene [XylNCCNXyl] moiety and the carbodiimido [NCNXyl] fragment in <b>2</b> have undergone net transformations. Similarly, <i>tert</i>-butyl isocyanide (<i>t</i>BuNC) reacts with the starting material <b>1</b> under mild conditions to give the paramagnetic derivative [{Ti₃(η⁵-C₅Me₅)₃­(μ-O)₃­(NCN<i>t</i>Bu)}₂­(μ-CN)₂] (<b>4</b>). However, compound <b>1</b> provides the oxo ketimide derivatives [{Ti₃(η⁵-C₅Me₅)₃­(μ-O)₄}­(NCRPh)] [R = Ph (<b>5</b>), <i>p</i>-Me­(C₆H₄) (<b>6</b>), <i>o</i>-Me­(C₆H₄) (<b>7</b>)] upon reaction with benzophenone, <i>p</i>-methylbenzophenone, and <i>o</i>-methylbenzophenone, respectively. In these reactions, the carbon–oxygen double bond is completely ruptured, leading to the formation of a carbon–nitrogen and two metal–oxygen bonds. The molecular structures of complexes <b>2</b>–<b>4</b>, <b>6</b>, and <b>7</b> were determined by single-crystal X-ray diffraction analyses. Density functional theory calculations were performed on the incorporation of isocyanides and ketones to the model complex [{Ti­(η⁵-C₅H₅)­(μ-O)}₃­(μ₃-N)] (<b>1H</b>). The mechanism involves the coordination of the substrates to one of the titanium metal centers, followed by an isomerization to place those substrates cis with respect to the apical nitrogen of <b>1H</b>, where carbon–nitrogen bond formation occurs with a low-energy barrier. In the case of aryl isocyanides, the resulting complex incorporates additional isocyanide molecules leading to a carbon–carbon coupling. With ketones, the high oxophilicity of titanium promotes the unusual total cleavage of the carbon–oxygen double bond

Modulating Nitric Oxide Release by <i>S</i>-Nitrosothiol Photocleavage: Mechanism and Substituent Effects

The photochemistry and photophysics of a series of <i>S</i>-nitrosothiols (RSNOs) have been studied computationally. The photocleavage mechanism of the model compound CH₃SNO to release CH₃S· and ·NO was studied at the CASPT2 level resulting in a barrierless process when irradiating in the visible region (S₁), in the near UV region (S₂) and for photosensitized (T₁) reaction. The absorption energy required to initiate photocleavage was calculated at the CASPT2 and B3P86 levels showing the possibility of the modulation of NO release by RSNO photoactivation as a function of the substituent R. Good correlations between the wavelengths of the lowest energy ¹(<i>n</i>,π*) and ¹(π,π*) transitions of aryl <i>S</i>-nitrosothiols and the corresponding Hammett constants of the substituents have been obtained

Conformational Preference and Chiroptical Response of Carbohydrates d‑Ribose and 2‑Deoxy‑d‑ribose in Aqueous and Solid Phases

This work targets the structural preferences of d-ribose and 2-deoxy-d-ribose in water solution and solid phase. A theoretical DFT (B3LYP and M06-2X) and MP2 study has been undertaken considering the five possible configurations (open-chain, α-furanose, β-furanose, α-pyranose, and β-pyranose) of these two carbohydrates with a comparison of the solvent treatment using only a continuum solvation model (PCM) and the PCM plus one explicit water molecule. In addition, experimental vibrational studies using both nonchiroptical (IR-Raman) and chiroptical (VCD) techniques have been carried out. The theoretical and experimental results show that α- and β-pyranose forms are the dominant configurations for both compounds. Moreover, it has been found that 2-deoxy-d-ribose presents a non-negligible percentage of open-chain forms in aqueous solution, while in solid phase this configuration is absent

Intermetallic Cooperation in C–H Activation Involving Transient Titanium-Alkylidene Species: A Synthetic and Mechanistic Study

Remote carbon–hydrogen activation on titanium dinuclear complexes [{Ti­(η⁵-C₅Me₅)­R₂}₂(μ-O)] [R = CH₂SiMe₃ <b>2</b>, CH₂CMe₃ <b>3</b>, and CH₂Ph <b>5</b>) have been examined both synthetically and theoretically. While the thermal treatment of the oxoderivative [{Ti­(η⁵-C₅Me₅)­(CH₂SiMe₃)₂}₂(μ-O)] (<b>2</b>) led to a series of metallacycle complexes (<b>2a</b>–<b>c</b>) by sequential carbon–hydrogen activation processes, [{Ti­(η⁵-C₅Me₅)­(CH₂CMe₃)₂}₂(μ-O)] (<b>3</b>) gave rise to the formation of the metallacycle tuck-over species [Ti₂(η⁵-C₅Me₅)­(μ-η⁵-C₅Me₄CH₂-κC)­(CH₂CMe₃)­(μ-CH₂CMe₂CH₂)­(μ-O)] (<b>4</b>), as result of hydrogen abstraction from a η⁵-C₅Me₅ ligand. However, the thermolysis of the tetrabenzyl complex [{Ti­(η⁵-C₅Me₅)­(CH₂Ph)₂}₂(μ-O)] (<b>5</b>) yielded the derivative [Ti₂(η⁵-C₅Me₅)­(μ-η⁵-C₅Me₄CH₂-κC)­(CH₂Ph)₃(μ-O)] (<b>6</b>) that only exhibits tuck-over η⁵-C₅Me₅ metalation. DFT calculations show that the mechanism involves a first α-hydrogen abstraction to generate a transient titanium alkylidene, which enables it to activate β- and γ-C­(sp³)-H bonds on the adjacent titanium center. The calculations also establish a reactivity order for the different type of γ-H abstractions, trimethylsilyl > neopentyl ≌ benzyl, allowing us to explain the observed selectivity