Framework para el desarrollo con el DNIe

El proyecto se trata de una API de desarrollo para el DNI electrónico que permita crear de forma sencilla aplicaciones cuya funcionalidad se apoye en el uso del DNI electrónico. De esta forma, el framework facilita el acceso a las principales operaciones soportadas por el DNIe mediante la invocación de métodos sencillos. Una de las funcionalidades es la de realizar un proceso de autenticación con el DNIe utilizando para ello las capacidades criptográficas del chip que incorpora y el certificado de autenticación. Esta funcionalidad puede ser accedida también de forma dividida en dos pasos, para dar soporte a aplicaciones con arquitectura cliente-servidor. El framework también ofrece la funcionalidad de firma electrónica con el DNIe, una firma legalmente válida y que permite chequear también la integridad del mensaje firmado. También se soporta por el framework la comprobación de un certificado mediante el protocolo OCSP, funcionalidad que si bien no implica directamente al DNIe, sí que es importante en el marco de procesos que se ven involucrados en cualquier Infraestructura de Clave Pública. ABSTRACT The project is a development API for DNIe card that allows easily create applications whose functionality is supported in the use of DNIe. Thus, the framework provides access to the main operations supported by the DNIe by invoking simple methods. One of the features is to perform an authentication process with the DNIe using its chip’s capabilities and authentication certificate. This functionality can also be accessed so divided into two steps, to support applications with client-server architecture. The framework also provides the functionality of electronic signatures with DNIe, a legally valid signature and allows also check the integrity of the signed message. Verification of a certificate using OCSP, functionality but does not imply directly to DNIe is also supported by the framework, yes it is important in the context of processes that are involved in any Public Key Infrastructure.

Telemetría de vehículos FSAE con microcontrolador PIC32 y transceptor de radio CC1101

Quizás el campo de las telecomunicaciones sea uno de los campos en el que más se ha progresado en este último siglo y medio, con la ayuda de otros campos de la ciencia y la técnica tales como la computación, la física electrónica, y un gran número de disciplinas, que se han utilizado estos últimos 150 años en conjunción para mejorarse unas con la ayuda de otras. Por ejemplo, la química ayuda a comprender y mejorar campos como la medicina, que también a su vez se ve mejorada por los progresos en la electrónica creados por los físicos y químicos, que poseen herramientas más potentes para calcular y simular debido a los progresos computacionales. Otro de los campos que ha sufrido un gran avance en este último siglo es el de la automoción, aunque estancados en el motor de combustión, los vehículos han sufrido enormes cambios debido a la irrupción de los avances en la electrónica del automóvil con multitud de sistemas ya ampliamente integrados en los vehículos actuales. La Formula SAE® o Formula Student es una competición de diseño, organizada por la SAE International (Society of Automotive Engineers) para estudiantes de universidades de todo el mundo que promueve la ingeniería a través de una competición donde los miembros del equipo diseñan, construyen, desarrollan y compiten en un pequeño y potente monoplaza. En el ámbito educativo, evitando el sistema tradicional de clases magistrales, se introducen cambios en las metodologías de enseñanza y surge el proyecto de la Fórmula Student para lograr una mejora en las acciones formativas, que permitan ir incorporando nuevos objetivos y diseñar nuevas situaciones de aprendizaje que supongan una oportunidad para el desarrollo de competencias de los alumnos, mejorar su formación como ingenieros y contrastar sus progresos compitiendo con las mejores universidades del mundo. En este proyecto se pretende dotar a los alumnos de las escuelas de ingeniería de la UPM que desarrollan el vehículo de FSAE de una herramienta de telemetría con la que evaluar y probar comportamiento del vehículo de FSAE junto con sus subsistemas que ellos mismos diseñan, con el objetivo de evaluar el comportamiento, introducir mejoras, analizar resultados de una manera más rápida y cómoda, con el objetivo de poder progresar más rápidamente en su desarrollo, recibiendo y almacenando una realimentación directa e instantánea del funcionamiento mediante la lectura de los datos que circulan por el bus CAN del vehículo. También ofrece la posibilidad de inyectar datos a los sistemas conectados al bus CAN de manera remota. Se engloba en el conjunto de proyectos de la FSAE, más concretamente en los basados en la plataforma PIC32 y propone una solución conjunta con otros proyectos o también por sí sola. Para la ejecución del proyecto se fabricó una placa compuesta de dos placas de circuito impreso, la de la estación base que envía comandos, instrucciones y datos para inyectar en el bus CAN del vehículo mediante radiofrecuencia y la placa que incorpora el vehículo que envía las tramas que circulan por el bus CAN del vehículo con los identificadores deseados, ejecuta los comandos recibidos por radiofrecuencia y salva las tramas CAN en una memoria USB o SD Card. Las dos PCBs constituyen el hardware del proyecto. El software se compone de dos programas. Un programa para la PCB del vehículo que emite los datos a la estación base, codificado en lenguaje C con ayuda del entorno de desarrollo MPLAB de Microchip. El otro programa hecho con LabView para la PCB de la estación base que recibe los datos provenientes del vehículo y los interpreta. Se propone un hardware y una capa o funciones de software para los microcontroladores PIC32 (similar al de otros proyectos del FSAE) para la transmisión de las tramas del bus CAN del vehículo de manera inalámbrica a una estación base, capaz de insertar tramas en el bus CAN del vehículo enviadas desde la estación base. También almacena estas tramas CAN en un dispositivo USB o SD Card situado en el vehículo. Para la transmisión de los datos se hizo un estudio de las frecuencias de transmisión, la legislación aplicable y los tipos de transceptores. Se optó por utilizar la banda de radiofrecuencia de uso común ISM de 433MHz mediante el transceptor integrado CC110L de Texas Instruments altamente configurable y con interfaz SPI. Se adquirieron dos parejas de módulos compatibles, con amplificador de potencia o sin él. LabView controla la estación que recoge las tramas CAN vía RF y está dotada del mismo transceptor de radio junto con un puente de comunicaciones SPI-USB, al que se puede acceder de dos diferentes maneras, mediante librerías dll, o mediante NI-VISA con transferencias RAW-USB. La aplicación desarrollada posee una interfaz configurable por el usuario para la muestra de los futuros sensores o actuadores que se incorporen en el vehículo y es capaz de interpretar las tramas CAN, mostrarlas, gráfica, numéricamente y almacenar esta información, como si fuera el cuadro de instrumentos del vehículo. Existe una limitación de la velocidad global del sistema en forma de cuello de botella que se crea debido a las limitaciones del transceptor CC110L por lo que si no se desea filtrar los datos que se crean necesarios, sería necesario aumentar el número de canales de radio para altas ocupaciones del bus CAN. Debido a la pérdida de relaciones con el INSIA, no se pudo probar de manera real en el propio vehículo, pero se hicieron pruebas satisfactorias (hasta 1,6 km) con una configuración de tramas CAN estándar a una velocidad de transmisión de 1 Mbit/s y un tiempo de bit de 1 microsegundo. El periférico CAN del PIC32 se programará para cumplir con estas especificaciones de la ECU del vehículo, que se presupone que es la MS3 Sport de Bosch, de la que LabView interpretará las tramas CAN recibidas de manera inalámbrica. Para poder probar el sistema, ha sido necesario reutilizar el hardware y adaptar el software del primer prototipo creado, que emite tramas CAN preprogramadas con una latencia también programable y que simulará al bus CAN proporcionando los datos a transmitir por el sistema que incorpora el vehículo. Durante el desarrollo de este proyecto, en las etapas finales, el fabricante del puente de comunicaciones SPI-USB MCP2210 liberó una librería (dll) compatible y sin errores, por lo que se nos ofrecía una oportunidad interesante para la comparación de las velocidades de acceso al transceptor de radio, que se presuponía y se comprobó más eficiente que la solución ya hecha mediante NI-VISA. ABSTRACT. The Formula SAE competition is an international university applied to technological innovation in vehicles racing type formula, in which each team, made up of students, should design, construct and test a prototype each year within certain rules. The challenge of FSAE is that it is an educational project farther away than a master class. The goal of the present project is to make a tool for other students to use it in his projects related to FSAE to test and improve the vehicle, and, the improvements that can be provided by the electronics could be materialized in a victory and win the competition with this competitive advantage. A telemetry system was developed. It sends the data provided by the car’s CAN bus through a radio frequency transceiver and receive commands to execute on the system, it provides by a base station on the ground. Moreover, constant verification in real time of the status of the car or data parameters like the revolutions per minute, pressure from collectors, water temperature, and so on, can be accessed from the base station on the ground, so that, it could be possible to study the behaviour of the vehicle in early phases of the car development. A printed circuit board, composed of two boards, and two software programs in two different languages, have been developed, and built for the project implementation. The software utilized to design the PCB is Orcad10.5/Layout. The base station PCB on a PC receives data from the PCB connected to the vehicle’s CAN bus and sends commands like set CAN filters or masks, activate data logger or inject CAN frames. This PCB is connected to a PC via USB and contains a bridge USB-SPI to communicate with a similar transceiver on the vehicle PCB. LabView controls this part of the system. A special virtual Instrument (VI) had been created in order to add future new elements to the vehicle, is a dashboard, which reads the data passed from the main VI and represents them graphically to studying the behaviour of the car on track. In this special VI other alums can make modifications to accommodate the data provided from the vehicle CAN’s bus to new elements on the vehicle, show or save the CAN frames in the form or format they want. Two methods to access to SPI bus of CC110l RF transceiver over LabView have been developed with minimum changes between them. Access through NI-VISA (Virtual Instrument Software Architecture) which is a standard for configuring, programming, USB interfaces or other devices in National Instruments LabView. And access through DLL (dynamic link library) supplied by the manufacturer of the bridge USB-SPI, Microchip. Then the work is done in two forms, but the dll solution developed shows better behaviour, and increase the speed of the system because has less overload of the USB bus due to a better efficiency of the dll solution versus VISA solution. The PCB connected to the vehicle’s CAN bus receives commands from the base station PCB on a PC, and, acts in function of the command or execute actions like to inject packets into CAN bus or activate data logger. Also sends over RF the CAN frames present on the bus, which can be filtered, to avoid unnecessary radio emissions or overflowing the RF transceiver. This PCB consists of two basic pieces: A microcontroller with 32 bit architecture PIC32MX795F512L from Microchip and the radio transceiver integrated circuit CC110l from Texas Instruments. The PIC32MX795F512L has an integrated CAN and several peripherals like SPI controllers that are utilized to communicate with RF transceiver and SD Card. The USB controller on the PIC32 is utilized to store CAN data on a USB memory, and change notification peripheral is utilized like an external interrupt. Hardware for other peripherals is accessible. The software part of this PCB is coded in C with MPLAB from Microchip, and programming over PICkit 3 Programmer, also from Microchip. Some of his libraries have been modified to work properly with this project and other was created specifically for this project. In the phase for RF selection and design is made a study to clarify the general aspects of regulations for the this project in order to understand it and select the proper band, frequency, and radio transceiver for the activities developed in the project. From the different options available it selects a common use band ICM, with less regulation and free to emit with restrictions and disadvantages like high occupation. The transceiver utilized to transmit and receive the data CC110l is an integrated circuit which needs fewer components from Texas Instruments and it can be accessed through SPI bus. Basically is a state machine which changes his state whit commands received over an SPI bus or internal events. The transceiver has several programmable general purpose Inputs and outputs. These GPIOs are connected to PIC32 change notification input to generate an interrupt or connected to GPIO to MCP2210 USB-SPI bridge to inform to the base station for a packet received. A two pair of modules of CC110l radio module kit from different output power has been purchased which includes an antenna. This is to keep away from fabrication mistakes in RF hardware part or designs, although reference design and gerbers files are available on the webpage of the chip manufacturer. A neck bottle is present on the complete system, because the maximum data rate of CC110l transceiver is a half than CAN bus data rate, hence for high occupation of CAN bus is recommendable to filter the data or add more radio channels, because the buffers can’t sustain this load along the time. Unfortunately, during the development of the project, the relations with the INSIA, who develops the vehicle, was lost, for this reason, will be made impossible to test the final phases of the project like integration on the car, final test of integration, place of the antenna, enclosure of the electronics, connectors selection, etc. To test or evaluate the system, it was necessary to simulate the CAN bus with a hardware to feed the system with entry data. An early hardware prototype was adapted his software to send programed CAN frames at a fixed data rate and certain timing who simulate several levels of occupation of the CAN Bus. This CAN frames emulates the Bosch ECU MS3 Sport.

Adaptación de GNU Radio a procesadores KeyStone II 66AK2xxx

En el presente proyecto se ha procedido a implantar la herramienta de procesado software GNU Radio en la tarjeta EVMK2H, que es un módulo de evaluación fabricado por Texas Instruments que incorpora un System on Chip (SoC) 66AK2H14 de la familia Keystone II, el cual dispone de 4 núcleos ARM y 8 núcleos DSP. Previamente a la instalación de GNU Radio, hubo que configurar la tarjeta, así como instalar el software necesario. De igual manera, se realizó una primera aproximación para comprender el funcionamiento de los sistemas de comunicación entre núcleos de que hace uso la tarjeta, y de los que se hizo uso posteriormente en el proyecto. Tras el portado de GNU Radio se ha comprobado el correcto funcionamiento del mecanismo de comunicación entre núcleos ARM y DSP con un par de aplicaciones de prueba. ABSTRACT. In the present project it was performed the implementation of the software processing toolkit GNU Radio into the EVMK2H board, which is an evaluation module from Texas Instruments that includes a 66AK2H14 System on Chip (SoC) from the Keystone II family, that provides 4 ARM cores and 8 DSP cores. Before installing GNU Radio, it was necessary to configure the board, and as well installing other needed software. Also, a first approach was performed to understand the way the communication system between cores included in the board works, which was used later in the project. After porting GNU Radio, some test applications have been written to test the correct operation of the communication mechanism between ARM and DSP cores.

O DISCURSO DE HUMANIZAÇÃO COMO ESTRATÉGIA DE APROXIMAÇÃO COM O CONSUMIDOR NAS PUBLICIDADES DAS MÍDIAS SOCIAIS

Este trabalho propõe o estudo analítico de estratégias discursivas das organizações empregadas nas publicidades das mídias sociais no Brasil em que, na tentativa de aproximação com os consumidores, as empresas emitem discursos de humanização. A pesquisa ocupou-se em identificar e analisar as publicidades das marcas notabilizadas nesse ambiente superabundante de informação, capazes de comunicar-se efetivamente com os consumidores, a ponto de levá-los ao engajamento com os interesses da organização pela interação e compartilhamento dos conteúdos nas mídias sociais, e de torná-los os agentes da marca, aqueles que divulgam voluntariamente os seus benefícios para a sua rede de amigos. Trata-se de uma pesquisa exploratória de teor qualitativo, cuja busca se dará pelas delineações de um espaço discursivo. Utilizou-se a análise do discurso (AD), da linha francesa, sob a perspectiva dos estudos do ethos, cenas de enunciação e contrato de comunicação que contemplam os discursos organizacionais. Além da conceituação teórica e revisão de literatura vinculadas às mídias sociais e cultura organizacional, o trabalho analisou as publicidades em vídeo publicadas no Facebook e YouTube, nos anos de 2014 e 2015, cujo intuito era a aproximação com o consumidor. A pesquisa demonstrou que o ambiente das mídias sociais requer outra postura das organizações, uma linguagem dialógica e interativa com a participação do consumidor nas suas publicidades. A supervalorização do consumidor e a sua inclusão nas narrativas é uma tentativa de humanizar as relações entre organização e seus públicos e demonstram ser o eixo conciliador entre ambos na nova ambiência midiática.

Genetic and root phenotype diversity in Sri Lankan rice landraces may be related to drought resistance

Acknowledgements Mayuri Munasinghe was supported by a Commonwealth Scholarship (ref no. LKCS-2009-384). The development and use of the SNP chip was funded by a BBSRC grant BB/J003336/1. The authors thank Owen Price (University of Wollongong, Australia) for producing the coloured province map of Sri Lanka, Gareth Norton (Aberdeen) for merging the RDP1 SNP data with the Sri Lankan data and Tony Travis (Aberdeen) for help with PCA.

Hsf1 and Hsp90 orchestrate temperature-dependent global transcriptional remodelling and chromatin architecture in Candida albicans

We thank Karim Gharbi and Urmi Trivedi for their assistance with RNA sequencing, carried out in the GenePool genomics facility (University of Edinburgh). We also thank Susan Fairley and Eduardo De Paiva Alves (Centre for Genome Enabled Biology and Medicine, University of Aberdeen) for help with the initial bioinformatics analysis. We thank Aaron Mitchell for kindly providing the ALS3 mutant, Julian Naglik for the gift of TR146 cells, and Jon Richardson for technical assistance. We thank the Genomics and Bioinformatics core of the Faculty of Health Sciences for Next Generation Sequencing and Bioinformatics support, the Information and Communication Technology Office at the University of Macau for providing access to a High Performance Computer and Jacky Chan and William Pang for their expert support on the High Performance Computer. Finally, we thank Amanda Veri for generating CaLC2928. M.D.L. is supported by a Sir Henry Wellcome Postdoctoral Fellowship (Wellcome Trust 096072), R.A.F. by a Wellcome Trust-Massachusetts Institute of Technology (MIT) Postdoctoral Fellowship, L.E.C. by a Canada Research Chair in Microbial Genomics and Infectious Disease and by Canadian Institutes of Health Research Grants MOP-119520 and MOP-86452, A.J. P.B. was supported by the UK Biotechnology and Biological Sciences Research Council (BB/F00513X/1) and by the European Research Council (ERC-2009-AdG-249793-STRIFE), KHW is supported by the Science and Technology Development Fund of Macau S.A.R (FDCT) (085/2014/A2) and the Research and Development Administrative Office of the University of Macau (SRG2014-00003-FHS) and R.T.W. by the Burroughs Wellcome fund and NIH R15AO094406. Data availability RNA-sequencing data sets are available at ArrayExpress (www.ebi.ac.uk) under accession code E-MTAB-4075. ChIP-seq data sets are available at the NCBI SRA database (http://www.ncbi.nlm.nih.gov) under accession code SRP071687. The authors declare that all other data supporting the findings of this study are available within the article and its supplementary information files, or from the corresponding author upon request.

DNA transport by a micromachined Brownian ratchet device

We have micromachined a silicon-chip device that transports DNA with a Brownian ratchet that rectifies the Brownian motion of microscopic particles. Transport properties for a DNA 50-mer agree with theoretical predictions, and the DNA diffusion constant agrees with previous experiments. This type of micromachine could provide a generic pump or separation component for DNA or other charged species as part of a microscale lab-on-a-chip. A device with reduced feature size could produce a size-based separation of DNA molecules, with applications including the detection of single-nucleotide polymorphisms.

Automated parallel DNA sequencing on multiple channel microchips

We report automated DNA sequencing in 16-channel microchips. A microchip prefilled with sieving matrix is aligned on a heating plate affixed to a movable platform. Samples are loaded into sample reservoirs by using an eight-tip pipetting device, and the chip is docked with an array of electrodes in the focal plane of a four-color scanning detection system. Under computer control, high voltage is applied to the appropriate reservoirs in a programmed sequence that injects and separates the DNA samples. An integrated four-color confocal fluorescent detector automatically scans all 16 channels. The system routinely yields more than 450 bases in 15 min in all 16 channels. In the best case using an automated base-calling program, 543 bases have been called at an accuracy of >99%. Separations, including automated chip loading and sample injection, normally are completed in less than 18 min. The advantages of DNA sequencing on capillary electrophoresis chips include uniform signal intensity and tolerance of high DNA template concentration. To understand the fundamentals of these unique features we developed a theoretical treatment of cross-channel chip injection that we call the differential concentration effect. We present experimental evidence consistent with the predictions of the theory.

Immobilization of oligodeoxyribonucleotides with multiple anchors to microchips

Facile modification of oligodeoxyribonucleotides is required for efficient immobilization to a pre-activated glass surface. This report presents an oligodeoxyribonucleotide which contains a hairpin stem–loop structure with multiple phosphorothioate moieties in the loop. These moieties are used to anchor the oligo to glass slides that are pre-activated with bromoacetamidopropylsilane. The efficiency of the attachment reaction was improved by increasing the number of phosphorothioates in the loop, as shown in the remarkable enhancement of template hybridization and single base extension through catalysis by DNA polymerase. The loop and stem presumably serve as lateral spacers between neighboring oligodeoxyribonucleotides and as a linker arm between the glass surface and the single-stranded sequence of interest. The oligodeoxyribonucleotides of this hairpin stem–loop architecture with multiple phosphorothioate moieties have broad application in DNA chip-based gene analysis.

Chemical nanoprinting: a novel method for fabricating DNA microchips

We have developed a novel cost-effective procedure, namely ‘chemical nanoprinting’, for oligonucleotide or cDNA chips manufacture. In this thermo-controlled process, the oligonucleotides, covalently attached to a highly loaded ‘master-chip’ through disulfide bonds, are chemically transferred to the acrylamide layer mounted on a ‘print-chip’. It is demonstrated here that multiple identical print-chips can be produced from a single master-chip. This duplication process is a few hundreds of times faster than any existing methods and the speed of process and cost incurred are independent of the scale of the DNA chips.

Manufacturing DNA microarrays of high spot homogeneity and reduced background signal

Analyses on DNA microarrays depend considerably on spot quality and a low background signal of the glass support. By using betaine as an additive to a spotting solution made of saline sodium citrate, both the binding efficiency of spotted PCR products and the homogeneity of the DNA spots is improved significantly on aminated surfaces such as glass slides coated with the widely used poly-l-lysine or aminosilane. In addition, non-specific background signal is markedly diminished. Concomitantly, during the arraying procedure, the betaine reduces evaporation from the microtitre dish wells, which hold the PCR products. Subsequent blocking of the chip surface with succinic anhydride was improved considerably in the presence of the non-polar, non-aqueous solvent 1,2-dichloroethane and the acylating catalyst N-methylimidazole. This procedure prevents the overall background signal that occurs with the frequently applied aqueous solvent 1-methyl-2-pyrrolidone in borate buffer because of DNA that re-dissolves from spots during the blocking process, only to bind again across the entire glass surface.

The challenge of contracting for technological information

Contracting to provide technological information (TI) is a significant challenge. TI is an unusual commodity in five ways. (i) TI is difficult to count and value; conventional indicators, such as patents and citations, hardly indicate value. TI is often sold at different prices to different parties. (ii) To value TI, it may be necessary to “give away the secret.” This danger, despite nondisclosure agreements, inhibits efforts to market TI. (iii) To prove its value, TI is often bundled into complete products, such as a computer chip or pharmaceutical product. Efficient exchange, by contrast, would involve merely the raw information. (iv) Sellers’ superior knowledge about TI’s value make buyers wary of overpaying. (v) Inefficient contracts are often designed to secure rents from TI. For example, licensing agreements charge more than marginal cost. These contracting difficulties affect the way TI is produced, encouraging self-reliance. This should be an advantage to large firms. However, small research and development firms spend more per employee than large firms, and nonprofit universities are major producers. Networks of organizational relationships, particularly between universities and industry, are critical in transmitting TI. Implicit barter—money for guidance—is common. Property rights for TI are hard to establish. Patents, quite suitable for better mousetraps, are inadequate for an era when we design better mice. Much TI is not patented, and what is patented sets fuzzy demarcations. New organizational forms are a promising approach to contracting difficulties for TI. Webs of relationships, formal and informal, involving universities, start-up firms, corporate giants, and venture capitalists play a major role in facilitating the production and spread of TI.

Effects of receptor dimerization on the interaction between the class I major histocompatibility complex-related Fc receptor and IgG.

The neonatal Fc receptor (FcRn) transports maternal IgG from ingested milk in the gut to the bloodstream of newborn mammals. An FcRn dimer was observed in crystals of the receptor alone and of an FcRn-Fc complex, but its biological relevance was unknown. Here we use surface plasmon resonance-based biosensor assays to assess the role of FcRn dimerization in IgG binding. We find high-affinity IgG binding when FcRn is immobilized on a biosensor chip in an orientation facilitating dimerization but not when its orientation disrupts dimerization. This result supports a model in which IgG-induced dimerization of FcRn is relevant for signaling the cell to initiate endocytosis of the IgG-FcRn complex.

Real-time detection of DNA hybridization and melting on oligonucleotide arrays by using optical wave guides.

The challenge of the Human Genome Project is to increase the rate of DNA sequence acquisition by two orders of magnitude to complete sequencing of the human genome by the year 2000. The present work describes a rapid detection method using a two-dimensional optical wave guide that allows measurement of real-time binding or melting of a light-scattering label on a DNA array. A particulate label on the target DNA acts as a light-scattering source when illuminated by the evanescent wave of the wave guide and only the label bound to the surface generates a signal. Imaging/visual examination of the scattered light permits interrogation of the entire array simultaneously. Hybridization specificity is equivalent to that obtained with a conventional system using autoradiography. Wave guide melting curves are consistent with those obtained in the liquid phase and single-base discrimination is facile. Dilution experiments showed an apparent lower limit of detection at 0.4 nM oligonucleotide. This performance is comparable to the best currently known fluorescence-based systems. In addition, wave guide detection allows manipulation of hybridization stringency during detection and thereby reduces DNA chip complexity. It is anticipated that this methodology will provide a powerful tool for diagnostic applications that require rapid cost-effective detection of variations from known sequences.