Biochemical analysis and optimization of inhibition and adsorption phenomena in glass-silicon PCR-chips

Altres ajuts: this work was partly funded by the Consejo de Investigaciones Cientı́ficas (CSIC), by Grant TIC97-0569 from the Comisión Interministerial de Ciencia y Tecnologı́a (CICYT)The use of glass-silicon chips for PCR analysis has been widely reported in the last decade, but there have been few systematic efforts to pin down the biochemical problems such systems bring forth. Here we report a systematic analysis of material-related inhibition and adsorption phenomena in glass-silicon PCR-chips. The results suggest that the previously reported inhibition of PCR by silicon-related materials stems mainly from the adsorption of Taq polymerase at chip walls due to increased surface-to-volume ratios, and not from a straight chemical action of silicon-related materials on the PCR-mix. In contrast to Taq polymerase, DNA is not adsorbed in noticeable amounts. The net effect of polymerase adsorption can be counteracted by the addition of a titrated amount of competing protein bovine serum albumin (BSA) and the ensuing reactions can be kinetically optimized in chips to yield effective amplifications in the whereabouts of 20 mi

Experiencia de innovación docente siguiendo las directrices del Espacio Europeo de Educación Superior en la enseñanza del diseño digital

El nuevo marco educativo superior establecido en la declaración de Bolonia ha introducido en nuestra metodología docente una serie de cambios muy significativos que, a nivel autonómico catalán, ha sido liderado por el DURSI (Departament d’Universitats, Recerca i Societat de la Informació). De esta forma, dicho departamento propuso la adaptación de ciertas titulaciones al futuro modelo europeo (EEES) entre las que se hallaba la de Ingeniería Informática. El departamento al que pertenecemos (Microelectrónica y Sistemas Electrónicos), ha puesto en marcha la implantación de una nueva metodología docente en un reducido número de asignaturas troncales, pertenecientes a la citada titulación, donde existe como factor común entre ellas, un alto grado de especialización tecnológica y un gran número de alumnos (más de 200). El objetivo fundamental de este trabajo es mostrar todo el proceso de adaptación que ha sido necesario para la ejecución con plenas garantías de dicha reforma educativa en nuestra asignatura (Diseño de Sistemas Digitales), así como todas las herramientas didácticas utilizadas para poder implantar dichas técnicas en una asignatura con un alto grado de experimentación práctica en los laboratorios y fomentar un mayor grado de participación y consecución de objetivos por parte del alumnado. Para conseguir el éxito final de dicho proceso, hemos utilizado una metodología docente basada en el PBL (“Problem Based Learning”), en el uso intensivo del conocido “e-learning, así como en una introducción progresiva al aprendizaje cooperativo; siempre siguiendo las directrices del grupo IDES (Grupo de Innovación Docente en Educación Superior) de la UAB. La asignatura en cuestión, ha sido estructurada en tres grandes secciones: Sesiones de teoría; Seminarios de problemas y Sesiones de laboratorios. En la sección de resultados evaluaremos el alto grado de objetivos cumplidos, la mejora significativa en el trabajo cooperativo, el incremento de la capacidad de organización y planificación, así como la buena capacidad en la resolución de problemas. A su vez, se ha conseguido que se haya obtenido un 91% de superación de la asignatura de los alumnos que han seguido los seminarios.The new higher educative framework established in the Bologna Declaration has introduced to our educational methodology a series of very significant changes that, at Catalan autonomic level, have been conducted by the DURSI (the Catalan Ministry of Universities, Research and the Information Society). With this aim, the ministry proposed the adaptation of certain degrees to the future European model, being Computer Engineering one of them. The department which we belong to (Department of Microelectronics and Electronic Systems), has started up the implantation of a new teaching methodology in a small number of core subjects, belonging to the aforementioned degree, which have in common a high level of technological specialization and a large number of students (more than 200). The main goal of our paper is to explain all the adaptation process that has been necessary for the execution of this educative reform in the subject we teach (Digital System Design). We also show all the didactic tools used to implant the new teaching methodology in a subject with a high level of experimentation in the laboratories. These tools also foment a greater degree of participation and attainment of objectives on the students’ part. In order to successfully carry out this process, we have used an educational methodology based on the Problem Based Learning technique (PBL) [2], the intensive use of e‐learning and the progressive introduction to the cooperative learning [3], always following the directives of the Unit for Innovation in Higher Education Teaching (IDES) from the UAB. The subject at issue has been structured in three great sections: Theory classes; Problem seminars y Laboratory sessions. In the results section, we will present the high level of fulfilled objectives, the significant improvement in cooperative working, the organization and planning capacity increase as well as the good aptitude in problem resolution. Moreover, the 91 per cent of the students who followed the seminars passed the subject

Development of a CMOS-compatible PCR chip : comparison of design and system strategies

Altres ajuts: this work was partly funded by the Consejo Superior de Investigaciones Científicas (CSIC), by grant TIC97-0569 from the Comision Interministerial de Ciencia y Tecnología (CICYT).In the last decade research in chips for DNA amplification through the polymerase chain reaction (PCR) has been relatively abundant, but has taken very diverse approaches, leaving little common ground for a straightforward comparison of results. Here we report the development of a line of PCR chips that is fully compatible with complementary-metal-oxide-semiconductor (CMOS) technology and its revealing use as a general platform to test and compare a wide range of experimental parameters involved in PCR-chip design and operation. Peltier-heated and polysilicon thin-film driven PCR chips have been produced and directly compared in terms of efficiency, speed and power consumption, showing that thin-film systems run faster and more efficiently than Peltier-based ones, but yield inferior PCR products. Serpentine-like chamber designs have also been compared with standard rectangular designs and with the here reported rhomboidal chamber shape, showing that serpentine-like chambers do not have detrimental effects in PCR efficiency when using non-flow-through schemes, and that chamber design has a strong impact on sample insertion/extraction yields. With an accurate temperature control (±0.2 °C) we have optimized reaction kinetics to yield sound PCR amplifications of 25 µl mixtures in 20 min and with 24.4 s cycle times, confirming that a titrated amount of bovine albumin serum (BSA, 2.5 µg µl−1) is essential to counteract polymerase adsorption at chip walls. The reported use of a CMOS-compatible technological process paves the way for an easy adaption to foundry requirements and for a scalable integration of electro-optic detection and control circuitr

Gate current analysis of AlGaN/GaN on silicon heterojunction transistors at the nanoscale

The gate leakage current of AlGaN/GaN (on silicon)high electron mobility transistor(HEMT) is investigated at the micro and nanoscale. The gate current dependence (25-310 °C) on the temperature is used to identify the potential conduction mechanisms, as trap assisted tunneling or field emission. The conductive atomic force microscopy investigation of the HEMT surface has revealed some correlation between the topography and the leakage current, which is analyzed in detail. The effect of introducing a thin dielectric in the gate is also discussed in the micro and the nanoscale

Psychosomatic response to acute emotional stress in healthy students

The multidimensionality of the stress response has shown the complexity of this phenomenon and therefore the impossibility of finding a unique biomarker among the physiological variables related to stress. An experimental study was designed and performed to guarantee the correct synchronous and concurrent measure of psychometric tests, biochemical variables and physiological features related to acute emotional stress. The population studied corresponds to a group of 120 university students between 20 and 30 years of age, with healthy habits and without a diagnosis of chronic or psychiatric illnesses. Following the protocol of the experimental pilot, each participant reached a relaxing state and a stress state in two sessions of measurement for equivalent periods. Both states are correctly achieved evidenced by the psychometric test results and the biochemical variables. A Stress Reference Scale is proposed based on these two sets of variables. Then, aiming for a non-invasive and continuous approach, the Acute Stress Model correlated to the previous scale is also proposed, supported only by physiological signals. Preliminary results support the feasibility of measuring/quantifying the stress level. Although the results are limited to the population and stimulus type, the procedure and methodological analysis used for the assessment of acute stress in young people can be extrapolated to other populations and types of stress

Microsistema multisensor basado en silicio.

Fecha de solicitud:22.08.2000.- Titulares: Consejo Superior de Investigaciones Cientícias (CSIC).- University of Amsterdam.- D+T Microelectrónica, A.I.E.- Hospital Universitari Vall D´Hebron.- Northern Ireland bio engineering genter.- Scuola superiore Santa Ana.[EN]The invention relates to a compact, millimeter-size silicon-based multisensor microsystem having the shape of a needle and comprising a series of sensors (to measure pH, analytes such K, sensors to measure impedance, temperature, etc.). Said microsystem also comprises pre-processing and signal amplification circuitry and telemetric circuitry of more than 3 megabits for short-distance data transmission. Said system is designed and optimized for applications in the field of medicine, more particularly, it can be used in tissue characterization and monitoring by inserting the system into a tissue, organ or body fluid.[ES]La invención se refiere a un microsistema compacto, multisensor milímetro de tamaño basado en el silicio que tiene la forma de una aguja, constituido por una serie de sensores (para medir el pH, los analitos, tales K , sensores para medir la impedancia, temperatura, etc.) microsistema Dijo también incluye pre-procesamiento y circuitos de amplificación de la señal y el circuito de telemetría de más de 3 megabits de transmisión de datos a corta distancia. Dicho sistema está diseñado y optimizado para aplicaciones en el campo de la medicina, en particular, puede ser utilizado en la caracterización de los tejidos y el control mediante la inserción del sistema en un tejido, órgano o líquidos corporales.Peer reviewe

Estrategias de Layout en circuitos hibridos analogicos-digitales

Peer reviewe

Sistema de control de micción, defecación y erección en pacientes con neuropatías.

Fecha de solicitud: 21.02.2001.- Titulares: Consejo Superior de Investigaciones Científicas (CSIC).- Fundación Instituto Guttmann.- Centro de Construcciones de Cardioestimuladores de Uruguay, S.A..[ES]The invention relates to a system for controlling incontinence, urination, defecation and erection in neuropathy patients by electric stimulation of the sacral roots. The system is based on an implantable stimulator powered by a battery and controlled by a microprocessor. It is programmed by means of a PC with the purpose of defining different operating modes, Said device is called programmer . Programs may be activated from the programmer or by using a compact portable apparatus called command . Said command makes it possible for the patient to start or stop execution of any of the programs that were previously loaded by the doctor. Communication of the stimulator with the programmer and the command is carried out by telemetry. Furthermore, deactivation of a running program can be brought about by the presence of a magnet. [ES]La invención se refiere a un sistema para controlar la incontinencia, micción, defecación y erección en pacientes con neuropatía por la estimulación eléctrica de las raíces sacras. El sistema se basa en un estimulador implantable alimentado por una batería y controlado por un microprocesador. Se programa por medio de un PC con el fin de definir diferentes modos de funcionamiento, Dicho dispositivo se llama programador. Los programas pueden ser activados desde el programador o mediante un comando compacto aparato llamado portátil. Dicho comando permite que el paciente para iniciar o detener la ejecución de cualquiera de los programas que se cargan previamente por el médico. Comunicación del estimulador con el programador y el comando se lleva a cabo por telemetría. Además, la desactivación de un programa en ejecución puede ser provocada por la presencia de un imán.Peer reviewe

Synthesis of sequential machines: a mathematical approach

A new mathematical approach for encoding internal states in synchronous sequential machines is developed. The relationship between transition matrices and the corresponding matrices of the isometric group is studied. An algorithm to a priori determine the null cost assignment is proposed. The cycle lengths which appear for each n are analysed. The results obtained for the D or SR flip-flop can be extended to JK and GL

Synthesis of sequential machines. A mathematical approach

A new mathematical approach for encoding internal states in synchronous sequential machines is developed. The relationship between transition matrices and the corresponding matrices of the isometric group is studied. An algorithm to a priori determine the null cost assignment is proposed. The cycle lengths which appear for each n are analysed. The results obtained for the D or SR flip-flop can be extended to JK and GL