Gotowa bibliografia na temat „RPC DETECTOR”

Il Large Hadron Collider (LHC) è l’acceleratore per collisioni di ioni e protoni attualmente in costruzione al CERN di Ginevra. Questa macchina permetterà di raggiungere un’elevata energia nel centro di massa (14 TeV per collisioni protone-protone), dando la possibilità di produrre particelle con masse fino all’ordine del TeV. ATLAS è uno degli esperimenti di LHC. Una delle principali caratteristiche del rivelatore di ATLAS è di avere uno spettrometro per muoni in aria, che opera come un rivelatore a sé stante. Nel barrel il trigger di primo livello dei muoni è fornito dalle camere RPC (Resistive Plate Chambers): rivelatori a gas in grado di fornire una risposta veloce con un’eccellente risoluzione temporale (σt ≤1.5 ns). In questa tesi sono presentati i risultati del primo test di funzionamento di un intero settore del rivelatore a muoni, svoltosi al test-beam H8 del CERN. Particolare attenzione è data allo studio sistematico della “cluster size” delle camere RPC (il numero di strisce contigue accese, che sono associate ad uno stesso segnale nel rivelatore). Questo studio ha mostrato come la “cluster size” osservata, lungi dall’essere casuale, dipenda in modo sistematico dal punto di impatto della particella sul piano di strisce di lettura. Viene inoltre descritto il test sistematico, mediante raggi cosmici, di 192 camere RPC di produzione (tipo BOL), che è stato allestito presso il laboratorio INFN di Roma Tor Vergata. Questo lavoro, che ha richiesto una corposa acquisizione dati, ha fornito la necessaria base statistica per uno studio accurato della rate di rumore e delle correnti di gap, dimostrando uno standard di qualità nella produzione seriale molto superiore a quello dei prototipi. L’ampia mole di dati acquisiti fornisce inoltre l’informazione necessaria per progredire nella comprensione della fisica del rivelatore. Successivamente viene presentata una simulazione Monte Carlo (in GEANT4) della logica di trigger di livello-1 con muoni cosmici, orientata a studiare le possibili configurazioni del trigger così da massimizzare la rate con i raggi cosmici durante la fase di “commissioning” del rivelatore. E’ stata inoltre prodotta una simulazione limitata a sei torri del trigger, al fine di verificare l’accordo dei risultati ottenuti con le rate misurate durante il primo test di “commissioning” nella caverna di ATLAS, permettendo così per la prima volta di validare il programma di simulazione. Infine viene presentata l’analisi dei dati prodotti durante il test in caverna delle prime tre torri assemblate dello spettrometro a muoni.<br>The Large Hadron Collider (LHC) is the machine for proton and ion collisions in construction at CERN of Geneva. It will provide a very high energy in the center of mass, reaching the value of 14 TeV for proton-proton collisions, and giving the possibility to produce particles with mass up to few TeV. ATLAS is one of the LHC experiments. The ATLAS detector is characterized by its stand-alone Muon Spectrometer, based on an air-core toroid system, which generates a large field volume and a strong bending power with a light and open structure. In the barrel the ATLAS first level muon trigger relies on the Resistive Plate Chambers (RPC): these are gas ionization detectors which are characterized by a fast response and an excellent time resolution (σt ≤1.5 ns). A good understanding of the detector physics and a complete control of the performance are essential. For this purpose, a cosmic muon test stand has been built in the INFN Roma Tor Vergata Laboratory and a systematic test of the 192 biggest ATLAS RPCs was carried out. It consisted of a preliminary check of the detector status (gas-tightness and test of the electric circuits), and a characterization of every chamber: in particular the noise rate, the cluster size, the detection efficiency and the gap current have been studied for each detector. Moreover at H8 beam site at CERN, an ATLAS-like detector slice was assembled and tested with particle beams. The presence in the test of the tracking chambers (MDT), combined with the RPCs, allowed to the author an independent study of the RPC performances, exploiting the information extracted from the muon tracks reconstructed by the precision chambers. The assembly of the ATLAS detector in the cavern has already started and will be completed in almost one year. Then a phase of detector calibration and test will precede the beginning of the experiment, using the RPCs as trigger of cosmic rays. To optimize the selection of the cosmic muons, the author studied dedicated first level muon trigger configurations, using a Monte Carlo simulation (based on GEANT4). Although the ATLAS detector installation in the cavern is still undergoing, some subdetectors are already operative: three muon stations of the lowest sector are ready and working. This allowed to validate the trigger simulation and furthermore to start the muon station debugging.

Orientador: Anderson Campos Fauth<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin<br>Made available in DSpace on 2018-07-26T17:58:58Z (GMT). No. of bitstreams: 1 Guidi_Anastasia_M.pdf: 234478 bytes, checksum: 319b960b6cc278eb3659e03644b94594 (MD5) Previous issue date: 2000<br>Resumo: Apresentamos um estudo sobre detectores a gás do tipo Resistive Plate Counter - RPC e sobre a viabilidade de sua utilização em experimentos de física de raios cósmicos. Discutimos os processos de formação e leitura do sinal quando da passagem de uma partícula ionizante pela região ativa do detector e apresentamos os resultados experimentais relevantes: espectros de carga, eficiência, contagem e resolução temporal. Obtivemos uma eficiência de 85 % e uma resolução temporal de 4ns, suficiente para a realização de medidas de 'tempo de vôo'. Os RPCs estudados foram construídos no Laboratório de Léptons do Instituto de Física Gleb Wataghin, Unicamp, a partir de componentes nacionais disponíveis no mercado. A modularidade dos RPCs e seu baixo custo sugerem que esses detectores são apropriados para experimentos de raios cósmicos, onde grandes áreas de detecção estão envolvidas<br>Abstract: We present a study about Resistive Plate Counters and the viability of their use in cosmic ray experiments. The processes of discharge formation by an ionizing particle and signal pick up are discussed, and the relevant experimental results ¿ charge spectra, efficiency, counting rates and time resolution are shown. An efficiency of 85 % and a time resolution of 4 ns, suitable for time of flight measurements, were achieved. The studied RPCs were assembled with brazilian commercially available materials at the Leptons Laboratory of the Gleb Wataghin Physics Department, Unicamp. The RPC's low cost and high modularity suggest their use in cosmic ray experiments, in which large detection areas are required.<br>Mestrado<br>Física<br>Mestre em Física

Este trabalho propõe um método biotelemétrico para a determinação simultânea de duas características elétricas (moduláveis por parâmetros fisiológicos) de circuitos RLC passivos para microsensores injetáveis. Como o ambiente sob monitoração envolve a presença de íons (tecidos biológicos), a utilização de dipolos torna-se inviável, desta forma, o estabelecimento de um acoplamento indutivo entre o sensor e o dispositivo para o registro das medidas é necessário. Tratando-se de um dispositivo injetável, as dimensões da bobina do sensor são diminutas (diâmetro da ordem de mm), sugerindo cuidados especiais quanto ao acoplamento indutivo do circuito RLC com o dispositivo de registro das medidas. Desta forma, foi desenvolvido um detector digital de freqüências, associado a um conjunto otimizado de bobinas para obter, a determinada distância (5 mm), a melhor indutância mútua possível com o microcircuito RLC remoto. Este dispositivo monitora o sensor em tempo real, informando a freqüência de ressonância, a sua respectiva amplitude a partir de uma varredura em freqüência. Um estudo analítico modelando a resposta em tensão do circuito detector segundo os estímulos e respostas que este fornece e recebe do circuito RLC remoto foi desenvolvido. O resultado desta análise, verificada praticamente, possibilitou a identificação da constante de tempo que cada degrau de freqüência deve ser mantido no sensor para que a resposta indicada seja a mais precisa possível. Decorrente desta análise foi possível modelar teoricamente a resistência total que o circuito RLC remoto apresenta. Assim, a partir das medidas de freqüência e amplitude do detector e do modelo teórico da resistência total do sensor o método foi estabelecido. Para verificar na prática a validade do método um micro sensor (2,8 x 23 mm) foi desenvolvido. O sensor foi encapsulado dentro de um tubo de silicone, apresentando um indutor montado junto a um bastão de ferrite, um capacitor SMD e um NTC, todos associados em paralelo. Com a alteração da distância entre o bastão de ferrite e o indutor (através da tração do tubo de silicone) a freqüência do sensor é alterada e a variação da resistência do NTC, através da temperatura, altera o fator de qualidade do sensor. A utilização do método para monitorar o sensor apresentou erros inferiores a 0,57 % para a indicação da freqüência e 0,77 % para a indicação da temperatura. A influência medida da variação da temperatura sobre a indicação da freqüência foi inferior a 0,16 %, indicando que o método é viável.<br>This work proposes a biotelemetric method to determine simultaneously two electrical characteristics (modulated by physiological parameters) from a passive injectable RLC microcircuit. Due to the presence of free ions inside the biological tissue, inductive links (loop antennas) must be employed, instead of dipole antennas. As the coil of the sensor presents small dimensions (diameter of about mm) its magnetic coupling to the monitoring device requires special attention. To monitor the sensor, a digital device assembled with a group of coils to maximize the mutual inductance (at a distance of 5 mm) between them was developed, detecting its resonance frequencies and the respective amplitude (through a frequency sweep) in real-time. The electrical response acquired by the detector from the sensor was analytically modeled. The model indicates a time constant to consider for each change of the signal frequencies to prevent errors in the response. From that theoretical model, an equation to determine the total resistance from the RLC circuit was obtained and confirmed by experiments. Then, a method to determine the resonance frequency and the total resistance from remote RLC circuit was proposed. A sensor was developed to verify the accuracy and the limits from this method. A parallel RLC circuit was built inside a silicone rubber tube. When the tube is stretched, a ferrite rod assembled beside the inductor is displaced varying the resonance frequency and, changing the environmental temperature, a NTC varies the quality factor of the circuit. Tests using the proposed method to monitor the sensor were realized. Errors small than 0.57 % in the resonance frequencies and 0.77 % in the temperature were obtained. The measured influence of the temperature variation over frequency determination was less than 0.16 %, indicating that the method is feasible.

The focus of this thesis is the development of Resistive Plate Chambers (RPCs) with ceramic electrodes. The use of ceramic composites, Si3N4/SiC, opens the way for the application of RPCs in harsh radiation environments. Future Experiments like the Compressed Baryonic Matter (CBM) at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt will need new RPCs with high rate capabilities and high radiation tolerance. Ceramic composites are specially suited for this purpose due to their resistance to radiation and chemical contamination. The bulk resistivity of these ceramics is in the range 10^7 - 10^13 Ohm cm. The bulk resistivity of the electrodes is the main factor determining the rate capabilities of a RPC, therefore a specifific measuring station and a measurement protocol has been set for these measurements. The dependence of the bulk resistivity on the difffferent steps of the manufacturing process has been studied. Other electrical parameters like the relaxation time, the relative permittivity and the tangent loss have also been investigated. Simulation codes for the investigation of RPC functionality was developed using the gas detectors simulation framework GARFIELD++. The parameters of the two mixtures used in RPC operation have been extracted. Furthermore, theoretical predictions on time resolution and effi ciency have been calculated and compared with experimental results. Two ceramic materials have been used to assemble RPCs. Si3N4/SiC and Al2O3 with a thin (nm thick) chromium layer deposited over it. Several prototypes have been assembled with active areas of 5x 5 cm^2, 10x 10 cm^2 and 20 x20 cm^2. The number of gaps ranges from two to six. The gas gap widths were 250 micro meter and 300 micrometer. As separator material mylar foils, fifishing line and high-resistive ceramics have been used. Different detector architectures have been built and their effffect on RPC performance analysed. The RPCs developed at HZDR and ITEP (Moscow) were systematically tested in electron and proton beams and with cosmic radiation over the course of three years. The performance of the RPCs was extracted from the measured data. The main parameters like time resolution, effi ciency, rate capabilities, cluster size, detector currents and avalanche charge were obtained and compared with other RPC systems in the world. A comparison with phenomenological models was performed.

Thesis (MMed)--Stellenbosch University, 2014.<br>ENGLISH ABSTRACT: Background Occult blood loss from the gastrointestinal tract (GIT), causing iron deficiency often with anaemia, can be diagnostically and therapeutically challenging. This is because the endoscopic and radiologic tests may be negative due to the slow, chronic and intermittent nature of the gastrointestinal bleeding, making timing key in detection and localisation of the bleed. These limitations can be approached using two different radioactive isotopes. Firstly, we tested the sensitivity of extending Cr-51 RBC for 21 days relative to 5 days to detect GIT bleeding and its use to optimise timing of a Tc-99m RBC study for GIT blood loss localisation. Finally, we tested if the information provided by the Tc-99m RBC study aided gastroenterologic intervention for anatomical localisation of a lesion. Method In this retrospective review, after obtaining institutional and ethics committee approval, records of patients referred for evaluation of possible GIT blood loss were reviewed. In each; daily appearance of radiochromium in stool was measured in the whole body counter. In those cases exceeding 50 ml/day, a technetium-99m (Tc-99m) localization study was performed. These studies were correlated with clinical findings. Results A total of 59 Cr-51 RBC studies were carried out in 36 females and 21 males (n = 57). In 32 (54%) the radiochromium results were positive with 75% of the bleeding incidences occurring after 5 days of stool collection. Of 17 cases in whom Tc-99m RBC imaging studies were performed, 14 (82%) were positive with specific anatomical sites successfully defined in twelve. In all patients with blood loss of >100 ml/24h, Tc-99m RBC were positive and localised. Ten of the 17 Tc-99m RBC studies were further investigated and half diagnosed with small-bowel angiodysplasia. Conclusion This sequential twin isotope method is practical in revealing otherwise silent intestinal haemorrhage. Although it has good patient acceptability and clinical as well as diagnostic utility in management, further studies are required to clearly establish a cut-off level of blood loss for performing imaging studies and the impact of the findings on the overall patient management.<br>AFRIKAANSE OPSOMMING: Agtergrond Die evaluasie van okkulte bloedverlies uit die gastro-intestinale kanaal (GIT), met gevolglike ystertekort anemie, kan diagnosties en terapeuties uitdagend wees. Dit is omdat endoskopiese en radiologiese ondersoeke negatief mag wees as gevolg van die stadige, chroniese en intermitterende aard van die gastro-intestinale bloeding, wat die presiese tydstip van opsporing en lokalisering van die bloeding krities belangrik maak. Hierdie beperkings kan aangespreek word deur twee verskillende radioaktiewe isotope te gebruik. Eerstens is die sensitiwiteit van die verlenging van die Cr-51 RBS studie tot 21 dae in plaas van 5 dae om die GIT bloeding op te spoor, getoets, asook die gebruik daarvan om die optimale tyd vir ‘n Tc-99m RBS studie om die GIT bloedverlies te lokaliseer, vas te stel. Laastens is getoets of die inligting van die Tc-99m RBS studie wel bygedra het tot die gastroenterologiese ingreep om die letsel anatomies te lokaliseer. Metode Na institusionele en etiese komitee toestemming is inligting van pasiënte wat vir die evaluering van ‘n moontlike GI bloedverlies verwys is, in hierdie retrospektiewe oorsig nagegaan. Die daaglikse voorkoms van radioaktiewe chroom in stoelgangmonsters is in ‘n heelliggaamteller gemeet. In gevalle waar dit 50 ml/dag oorskry het, is ‘n tegnesium 99m (Tc 99m) studie gedoen. Hierdie studies is met die kliniese bevindinge gekorreleer. Resultate ‘n Totaal van 59 Cr-51 RBS studies is in 36 vroue en 21 mans (n = 57) gedoen. Die gemerkte chroomstudies was positief in 32 (54%), met 75% van die bloedings wat meer as 5 dae na versameling van die stoelgang plaasgevind het. In veertien (82%) van die 17 gevalle waar Tc-99m RBS studies gedoen is, was die studies positief. Spesifieke anatomiese gebiede van bloeding kon in 12 hiervan suksesvol bevestig word. Tc-99m RBS studies was positief in al die pasiënte met ‘n bloedverlies van >100 ml/24h, en kon gelokaliseer word. Tien van die 17 Tc-99m RBS studies is verder ondersoek en die helfte daarvan gediagnoseer met dunderm angiodisplasie. Gevolgtrekking Die opeenvolgende twee isotoopmetode om andersins asimptomatiese dermbloeding op te spoor, is prakties uitvoerbaar. Alhoewel die studies goed deur pasiënte aanvaar is, en ook van kliniese en diagnostiese waarde in die hantering van die pasiënte is, is verdere studies nodig om die afsnypunt vir die hoeveelheid bloedverlies om beeldingstudies uit te voer, sonder twyfel vas te stel, asook om die impak van die bevindings op ‘n groter pasiëntpopulasie vas te stel.

When studying detection systems, parameters associated with the Receiver Operating Characteristic (ROC) curve are often estimated to assess system performance. In some applied settings it is often not possible to test the detection system with large numbers of stimuli. The resulting small sample statistics many have undesirable properties. The characteristics of these small sample ROC estimators were examined in a Monte Carlo simulation. Three popular ROC parameters were chosen for study. One of the parameters was a single parameter index of system performance, Area under the ROC curve. The other parameters, ROC intercept and slope, were considered as a pair. ROC intercept and slope were varied along with sample size and points on the certainty rating scale to form a four way factorial design. Several types of estimators were examined. For the parameter, Area under the curve, Maximum Likelihood (ML), three types of Least Squares (LS), and Distribution Free (DF) estimators were considered. Except for the DF estimator, the same estimators were considered for the parameters, intercept and slope. These estimators were compared with respect to three characteristics: bias, efficiency, and consistency. For Area under the curve, the ML estimator was the least biased. The DF estimator was the most efficient, and all the estimators except the DF estimator appeared to be consistent. For intercept and slope the LS estimator that minimized vertical error of the points from the ROC curve (line) was the least biased for both estimators. This LS estimator was also the most efficient. This estimator along with the ML estimator also appeared to be the most consistent. The other two estimators had no significant trend toward consistency. These results along with other findings, illustrate that different estimators may be "best" for different sample sizes and for different parameters. Therefore, researchers should carefully consider the characteristics of ROC estimators before using them as indices of system performance.

Avui en dia, hi ha la necessitat de desenvolupar un sistema per a la detecció d'ADN que sigui ràpid, simple, econòmic i reproduïble per al diagnòstic en diferents camps com malalties genètiques, detecció de patògens, medicina forense i medicina personalitzada.Els mètodes convencionals per a la detecció de seqüències d'ADN específiques es basen en assajos de seqüenciació directa o d'hibridació, essent aquest últim el més utilitzat en genosensors. Aquest mètode consisteix en l'ús de superfícies transductores modificades amb sondes d'ADN monocatenari, que reconeixen la seva seqüència complementària (diana) amb alta afinitat i especificitat.Una de les limitacions de l'aplicació d'aquests sensors a dispositius portàtils és la necessitat de la realització d'etapes posteriors a l'amplificació. Aquestes etapes inclouen la generació d'ADN monocatenari o la seva modificació amb un marcador abans de assolir la detecció.En aquest treball, es combina l'amplificació isotèrmica i l'ús d'encebadors modificats per simplificar les etapes necessàries per la detecció electroquímica d'ADN. Aquests encebadors, contenen una seqüència d'oligonucleòtids monocatenària unida a un espaiador de carboni, que bloqueja eficaçment l'elongació, abans de la seqüència del encebador. Per tant, el producte final està compost per un ADN de doble cadena flanquejat per dues cues d'ADN monocatenàries. Una de les cues es va utilitzar per hibridar a una sonda immobilitzada en la superfície i l'altra a una sonda marcada amb enzims o nanopartícules d'or. L'ús d'aquests encebadors modificats van permetre detectar l’ADN electroquímicament sense necessitat d'un tractament posterior a l'amplificació de la mostra, disminuint el temps d'assaig i presentant un enfocament més portable per ser aplicat en qualsevol situació.<br>Hoy en día, existe la necesidad de desarrollar un sistema para la detección de ADN que sea rápido, simple, económico y reproducible para el diagnóstico en diferentes campos como enfermedades genéticas, detección de patógenos, medicina forense y medicina personalizada.Los métodos convencionales para la detección de secuencias de ADN específicas se basan en ensayos de secuenciación directa o de hibridación, siendo este último el más utilizado en genosensores. Este método consiste en el uso de superficies transductoras modificadas con sondas de ADN monocatenario (ssDNA), que reconocen su secuencia complementaria (diana) con alta afinidad y especificidad.Una de las limitaciones de la aplicación de estos sensores a dispositivos portátiles es la necesidad de la realización de etapas posteriores a la amplificación. Estas etapas incluyen la generación de ADN monocatenario o su modificación con un marcador antes de pasar a la detección.En este trabajo, se combina la amplificación isotérmica y el uso de cebadores modificados para simplificar los pasos necesarios para la detección electroquímica de ADN. Estos cebadores, contienen una secuencia de oligonucleótidos monocatenaria unida a un espaciador de carbono, que bloquea eficazmente la elongación, antes de la secuencia del cebador. Por lo tanto, el producto final está compuesto por un ADN de doble cadena flanqueado por dos colas de ADN monocatenarias. Una de las colas se usó para hibridar a una sonda inmovilizada en la superficie y la otra a una sonda marcada con enzimas o nanopartículas de oro. El uso de estos cebadores modificados permitió detectar ADN electroquímicamente sin necesidad de un tratamiento posterior a la amplificación de la muestra, disminuyendo el tiempo de ensayo y presentando un enfoque más portable para ser aplicado en cualquier situación<br>Nowadays, there is a need to develop a rapid, simple, inexpensive and reliable DNA testing system for diagnosis in different fields such as genetic diseases, pathogens detection, forensics, and personalised medicine. Conventional methods for the detection of specific DNA sequences are based on direct sequencing or hybridisation assays, being this last one approach, the most widely used in genosensors. It consists on single-stranded DNA (ssDNA) tethered probes on a transducer surface, which recognises its complementary sequence (target) with high affinity and specificity. One of the limitations of these DNA sensors to apply them for a portable molecular diagnostics devices is the multi-step procedures needed, since post-amplification treatment is necessary for its detection by generating ssDNA or adding a hapten labelling. In this work, the isothermal amplification and modified tailed primers to simplify the steps required for the electrochemical DNA detection are combined. Modified tailed primers are based on a single stranded oligonucleotide sequence linked to a carbon spacer, which effectively blocks elongation, prior to the primer sequence. Thus, resulting in an amplicon with a duplex flanked by two single stranded DNA tails. One of the tails was used to hybridise to a surface immobilised probe and the other to an enzyme or gold nanoparticles labelled reporter probe. Using these modified primers allowed us to detect DNA electrochemically without any need for post-amplification sample treatment decreasing the assay time and presenting an approach that can facilely find application at the point of need.

L'objectiu general d'aquesta tesi doctoral és desenvolupar plataformes de geno-sensors de baix cost per a la detecció múltiple de polimorfismes d'un sol nucleòtid. La determinació de polimorfismes d'un sol nucleòtid (SNP) és de gran importància en les ciències de la vida, tenint aplicació en la medicina personalitzada, estratificació de pacients, forense, a més de brindar informació sobre la predisposició a la malaltia. En l'actualitat, els mètodes basats en l'electroquímica es revelen com alternatives atractives a les tècniques més utilitzades per determinar el punt de fusió de l'ADN, per la seva alta sensibilitat, simplicitat, rendibilitat i compatibilitat amb la microfabricació. La primera plataforma es va basar en una reacció d'extensió d'encebadors electroquímics, on els polioximetalats actius redox de Keggin i Dawson es van utilitzar per modificar dideoxinucleótids a través de la formació d'enllaços amida. La segona plataforma es basa en la detecció de polimorfismes d'un sol nucleòtid mitjançant l'anàlisi electroquímic de la corba de desnaturalització. L'enfocament es basa en l'anàlisi de la corba de desnaturalització en fase sòlida que utilitza sondes immobilitzades en elèctrodes d'or. Es va desenvolupar un prototip de dispositiu capaç de detectar un ADN diana que porta un SNP relacionat amb la miocardiopatia amb una sola base en la diferència. Finalment, aquest dispositiu es va aplicar a la detecció de SNP en mostres de sang reals. La diana de seqüència de SNP relacionada amb l'osteoporosi es va extreure d'una punxada al dit i es va amplificar usant PCR asimètrica. A més, es van optimitzar les condicions d'amplificació per obtenir el millor rendiment del producte i es va definir l'SNP d'una mostra de sang.<br>El objetivo general de esta tesis doctoral es desarrollar plataformas de geno-sensores de bajo costo para la detección múltiple de polimorfismos de un solo nucleótido. La determinación de polimorfismos de un solo nucleótido (SNP) es de gran importancia en las ciencias de la vida, teniendo aplicación en la medicina personalizada, estratificación de pacientes, forense, además de brindar información sobre la predisposición a la enfermedad. En la actualidad, los métodos basados en la electroquímica se revelan como alternativas atractivas a las técnicas más utilizadas para determinar el punto de fusión del ADN, debido a su alta sensibilidad, simplicidad, rentabilidad y compatibilidad con la microfabricación. La primera plataforma se basó en una reacción de extensión de cebadores electroquímicos, donde los polioximetalatos activos redox de Keggin y Dawson se utilizaron para modificar didesoxinucleótidos a través de la formación de enlaces amida. La segunda plataforma se basa en la detección de polimorfismos de un solo nucleótido mediante el análisis electroquímico de la curva de desnaturalización. El enfoque se basa en el análisis de la curva de desnaturalización en fase sólida que utiliza sondas inmovilizadas en electrodos de oro. Se desarrolló un prototipo de dispositivo capaz de detectar un ADN diana que porta un SNP relacionado con la miocardiopatía con una sola base en la diferencia. Finalmente, este dispositivo se aplicó a la detección de SNP en muestras de sangre reales. La diana de secuencia de SNP relacionada con la osteoporosis se extrajo de un pinchazo en el dedo y se amplificó usando PCR asimétrica. Además, se optimizaron las condiciones de amplificación para obtener el mejor rendimiento del producto y se definió el SNP de una muestra de sangre.<br>The overall objective of this PhD thesis is to develop low cost geno-sensor platforms for multiplexed detection of single nucleotide polymorphism. The determination of single nucleotide polymorphisms (SNP) is of great importance in life sciences, having application in personalised medicine, patient stratification, forensics, as well as providing information regarding predisposition to disease. Nowadays electrochemistry-based methods are revealed as attractive alternatives to the most commonly used techniques for determining DNA melting point, because of their high sensitivity, simplicity, cost-effective and compatibility with microfabrication. The first platform was based on an electrochemical primer extension reaction, where the redox active Keggin and Dawson polyoxymetalates were used to modify dideoxynucleotides through amide bond formation. The second platform is based on the detection of single nucleotide polymorphisms using electrochemical melting curve analysis. The approach is based on solid phase melting curve analysis that exploits probes immobilised on gold electrodes. We developed a home-made electrochemical melting curve analysis device, able to detect a DNA target that carries a SNP related to cardiomyopathy from others with only one base in difference. Finally, this device was applied to SNPs detection in real blood samples. Osteoporosis related SNP sequence target was extracted from a finger prick and amplified using asymmetric Recombinase Polymerase Amplification. Also, the amplification conditions were optimised for best product yield, and the SNP from a blood sample was defined.

This diploma thesis deals with pause identification with degraded speech signal. The speech characteristics and the conception of speech signal processing are described here. The work aim was to create the reliable recognizing method to establish speech and non-speech segments of speech signal with and without degraded speech signal. The five empty pause detectors were realized in computing environment MATLAB. There was the energetic detector in time domain, two-step detector in spectral domain, one-step integral detector, two-step integral detector and differential detector in cepstrum. The spectral detector makes use of energetic characteristics of speech signal in first step and statistic analysis in second step. Cepstral detectors make use of integral or differential algorithms. The detectors robustness was tested for different types of speech degradation and different values of Signal to Noise Ratio. The test of influence different speech degradation was conducted to compare non-speech detection for detectors by ROC (Receiver Operating Characteristic) Curves.