A Novel Approach to Describe the Time-Temperature Conversion among Relaxation Curves of Viscoelastic Materials.

Time and temperature, besides pressure in a lesser extent, represent the most significant variables influencing the rheological behavior of viscoelastic materials. These magnitudes are each other related through the well-known Time-Temperature Superposition (TTS) principle, which allows the master curve referred to relaxation (or creep) behavior to be derived as a material characteristic. In this work, a novel conversion law to interrelate relaxation curves at different temperatures is proposed by assuming they to be represented by statistical cumulative distribution functions of the normal or Gumbel family. The first alternative responds to physical considerations while the latter implies the fulfillment of extreme value conditions. Both distributions are used to illustrate the suitability of the model when applied to reliable derivation of the master curve of Polyvinil-Butyral (PVB) from data of experimental programs. The new approach allows not only the TTS shift factors to be estimated by a unique step, but the whole family of viscoelastic master curves to be determined for the material at any temperature. This represents a significant advance in the characterization of viscoelastic materials and, consequently, in the application of the TTS principle to practical design of viscoelastic components.

Asynchronous Detection of Trials Onset from Raw EEG Signals.

Clinical processing of event-related potentials (ERPs) requires a precise synchrony between the stimulation and the acquisition units that are guaranteed by means of a physical link between them. This precise synchrony is needed since temporal misalignments during trial averaging can lead to high deviations of peak times, thus causing error in diagnosis or inefficiency in classification in brain-computer interfaces (BCIs). Out of the laboratory, mobile EEG systems and BCI headsets are not provided with the physical link, thus being inadequate for acquisition of ERPs. In this study, we propose a method for the asynchronous detection of trials onset from raw EEG without physical links. We validate it with a BCI application based on the dichotic listening task. The user goal was to attend the cued auditory message and to report three keywords contained in it while ignoring the other message. The BCI goal was to detect the attended message from the analysis of auditory ERPs. The rate of successful onset detection in both synchronous (using the real onset) and asynchronous (blind detection of trial onset from raw EEG) was 73% with a synchronization error of less than 1[Formula: see text]ms. The level of synchronization provided by this proposal would allow home-based acquisition of ERPs with low cost BCI headsets and any media player unit without physical links between them.

A binary phase-shift keying receiver for the detection of attention to human speech.

Synthetic sounds, tone-beeps, vowels or syllables are typically used in the assessment of attention to auditory stimuli because they evoke a set of well-known event-related potentials, whose characteristics can be statistically contrasted. Such approach rules out the use of stimuli with non-predictable response, such as human speech. In this study we present a procedure based on the robust binary phase-shift keying (BPSK) receiver that permits the real-time detection of selective attention to human speeches in dichotic listening tasks. The goal was achieved by tagging the speeches with two barely-audible tags whose joined EEG response constitutes a reliable BPSK constellation, which can be detected by means of a BPSK receiver. The results confirmed the expected generation of the BPSK constellation by the human auditory system. Also, the bit-error rate and the information transmission rate achieved in the detection of attention fairly followed the expected curves and equations of the standard BPSK receiver. Actually, it was possible to detect attention as well as the estimation a priori of its accuracy based on the signal-to-noise ratio of the BPSK signals. This procedure, which permits the detection of the attention to human speeches, can be of interest for new potential applications, such as brain-computer interfaces, clinical assessment of the attention in real time or for entertainment.

An auditory brain­computer interface evoked by natural speech.

Brain­computer interfaces (BCIs) are mainly intended for people unable to perform any muscular movement, such as patients in a complete locked-in state. The majority of BCIs interact visually with the user, either in the form of stimulation or biofeedback. However, visual BCIs challenge their ultimate use because they require the subjects to gaze, explore and shift eye-gaze using their muscles, thus excluding patients in a complete locked-in state or under the condition of the unresponsive wakefulness syndrome. In this study, we present a novel fully auditory EEG-BCI based on a dichotic listening paradigm using human voice for stimulation. This interface has been evaluated with healthy volunteers, achieving an average information transmission rate of 1.5 bits min⁻¹ in full-length trials and 2.7 bits min⁻¹ using the optimal length of trials, recorded with only one channel and without formal training. This novel technique opens the door to a more natural communication with users unable to use visual BCIs, with promising results in terms of performance, usability, training and cognitive effort.

An auditory brain-computer interface with accuracy prediction.

Fully auditory Brain-computer interfaces based on the dichotic listening task (DL-BCIs) are suited for users unable to do any muscular movement, which includes gazing, exploration or coordination of their eyes looking for inputs in form of feedback, stimulation or visual support. However, one of their disadvantages, in contrast with the visual BCIs, is their lower performance that makes them not adequate in applications that require a high accuracy. To overcome this disadvantage, we employed a Bayesian approach in which the DL-BCI was modeled as a Binary phase shift keying receiver for which the accuracy can be estimated a priori as a function of the signal-to-noise ratio. The results showed the measured accuracy to match the predefined target accuracy, thus validating this model that made possible to estimate in advance the classification accuracy on a trial-by-trial basis. This constitutes a novel methodology in the design of fully auditory DL-BCIs that let us first, define the target accuracy for a specific application and second, classify when the signal-to-noise ratio guarantees that target accuracy.

Gasto farmacéutico derivado de la prescripción de antibióticos a la población pediátrica de Castilla y León en los últimos diez años / Pharmaceutical expenditure derived from antibiotic prescription to the pediatric population in Castilla y León in the last ten years

Introducción: la crisis económica y sus consecuencias están suponiendo dificultades para la sostenibilidad de la prestación farmacéutica y del propio sistema sanitario. Entre los grupos terapéuticos de mayor consumo en población infantil se encuentran los antibióticos. Objetivo: descripción y análisis del coste del tratamiento en antibióticos prescritos a la población pediátrica de Castilla y León en la última década, en el ámbito extrahospitalario. Material y métodos: las bases de datos de gasto de antimicrobianos con cargo al Sistema Nacional de Salud provienen de Concylia. Indicadores de consumo: Euros (€)/dosis definida/día y €/1000 habitantes/día. Resultados: se ha registrado un gasto en antibióticos de 15 750 829,26 €. Las penicilinas asociadasa inhibidores de la betalactamasa (amoxicilina con clavulánico) son responsables del 32,62% del gasto, seguidas de las cefalosporinas y los macrólidos. En último lugar se encontrarían las penicilinas de amplio espectro (amoxicilina), pese a ser las más prescritas. La evolución interanual refleja un llamativodescenso en el precio de la mayoría de los antibióticos, principalmente durante los últimos cinco años. El análisis del gasto disgregado por áreas de salud muestra también importantes diferencias. Conclusión: las variaciones en el gasto están motivadas principalmente por la frecuencia de uso y por modificaciones en los precios de venta al público. La amoxicilina-clavulánico es el antibiótico que supone más gasto. Los macrólidos son los antibióticos de mayor precio y la amoxicilina el de menor. Se observa una tendencia descendente del gasto en la mayoría de los antibióticos a lo largo del decenio(AU)

Introduction: the economic crisis and its consequences are posing difficulties for the sustainability of providing a pharmaceutical and health care system. Antibiotics are the therapeutic groups with the highest consumption in children. Objective: description and analysis of the cost of prescribed antibiotics in the paediatric populationof Castilla and Leon in the last decade, in the community setting. Methods: the databases of antimicrobials' expenditure financed by the NHS come from Concylia. Consume indicators: Euro (€)/DDD and €/1000 inhabitants/day. Results: there has been an antibiotic cost of € 15,750,829.26. Penicillins associated with beta lactamase inhibitors (amoxicillin with clavulanic acid) are responsible for 32.62% of spending, followedby cephalosporins and macrolides. In the last place are the broad-spectrum penicillins (amoxicillin),although they are the most prescribed antibiotics. The annual evolution reflects a sharp drop in the price of most antibiotics mainly during the last five years. Disaggregated analysis of spending by Health Areas also shows important differences. Conclusions: variations in spending are driven primarily by the frequency of use and changes in retail prices. Amoxicillin clavulanate is the antibiotic responsible for the highest expense. Macrolides are the most expensive antibiotics and amoxicillin the lowest ones. There is a downward trend in spending in most antibiotics along the decade(AU)

Customized stimulation enhances performance of independent binary SSVEP-BCIs.

OBJECTIVE: Brain-computer interfaces based on steady-state visual evoked potentials (SSVEP-BCIs) achieve the highest performance, due to their multiclass nature, in paradigms in which different visual stimuli are shown. Studies of independent binary SSVEP-BCIs have been previously presented in which it was not necessary to gaze at the stimuli at the cost of performance. Despite that, the energy of the SSVEPs is largely affected by the temporal and spatial frequencies of the stimulus, there are no studies in the BCI literature about its combined impact on the final performance of SSVEP-BCIs. The objective of this study is to present an experiment that evaluates the best configuration of the visual stimulus for each subject, thus minimizing the decline in performance of independent binary SSVEP-BCIs. METHODS: The participants attended and ignored a single structured stimulus configured with a combination of spatial and temporal frequencies at a time. They were instructed to gaze at a central point during the whole experiment. The best combination of spatial and temporal frequencies achieved for each subject, in terms of signal-to-noise ratio (SNR), was subsequently determined. RESULTS: The SNR showed a significant dependency on the combination of frequencies, in such a way that only a reduced set of these combinations was applicable for obtaining an optimum SNR. The selection of an inappropriate stimulus configuration may cause a degradation of the information transmission rate (ITR) as it does the SNR. CONCLUSIONS: The appropriate selection of the optimal spatial and temporal frequencies determines the performance of independent binary SSVEP-BCIs. This fact is critical to enhance its low performance; hence, they should be adjusted independently for each subject. SIGNIFICANCE: Independent binary SSVEP-BCIs can be used in patients who are unable to control their gaze sufficiently. The correct selection of the spatial and temporal frequencies has a considerable benefit on their low ITR that must be taken into account. In order to find the most suitable frequencies, a test similar to the presented in this study should be performed beforehand for each SSVEP-BCI user. This regard is not documented in studies conducted in the BCI literature.

Development of a cortical visual neuroprosthesis for the blind: the relevance of neuroplasticity.

Clinical applications such as artificial vision require extraordinary, diverse, lengthy and intimate collaborations among basic scientists, engineers and clinicians. In this review, we present the state of research on a visual neuroprosthesis designed to interface with the occipital visual cortex as a means through which a limited, but useful, visual sense could be restored in profoundly blind individuals. We review the most important physiological principles regarding this neuroprosthetic approach and emphasize the role of neural plasticity in order to achieve desired behavioral outcomes. While full restoration of fine detailed vision with current technology is unlikely in the immediate near future, the discrimination of shapes and the localization of objects should be possible allowing blind subjects to navigate in a unfamiliar environment and perhaps even to read enlarged text. Continued research and development in neuroprosthesis technology will likely result in a substantial improvement in the quality of life of blind and visually impaired individuals.

Ventajas e inconvenientes de la anticoagulación oral en Atención Primaria / Advantages and inconveniences of the oral anticoagulation in Primary Care

No disponible

[Internet application for medical purposes in chronic patients cared in a systemic autoimmune diseases unit]. / Utilización de Internet como fuente de información por los pacientes de una consulta de Enfermedades Autoinmunes Sistémicas.

OBJECTIVE: In recent years Internet has become an important tool for medical information search, not only for physicians but also for the patients. Little is known about Internet patient's use in Spain. Our objective was to study the frequency with which patients with different chronic autoimmune diseases cared in our unit use Internet as a source of medical information, and to identify the factors associated with its use. METHODS: A survey was carried out on Internet use to patients cared in a teaching hospital Systemic Autoimmune Diseases unit along three consecutive weeks. RESULTS: Hundred thirty-eight patients completed the questionnaire. Eighty-seven (63%) were women. Fifty-four patients (39.1%) were older than 55 years. Mean disease progression was 34.2 +/- 39.2 months. 22% of the respondents were uneducated, 39% had elementary education level; 20% had average education level, and 20% had advanced education level. Forty-two patients (30.4%) used regularly Internet for any purpose. Factors associated to Internet use for medical purposes were regular Internet use (OR: 4.6; CI: 1.1-18.8;p = 0.03), and average or advanced educational degree (advanced education: OR: 22.9; CI: 2.6-202.7; p = 0.005; average education: OR: 8.5; CI: 1.2-59.6; p = 0.03). Eighty-one patients (58.7%) expressed their need of information on quality web pages. CONCLUSIONS: Many patients use Internet for medical purposes in our environment and even more consider to use it in the future. It is important to be aware of this fact and facilitate information about quality web pages for interested patients.

Utilización de Internet como fuente de información por los pacientes de una consulta de Enfermedades Autoinmunes Sistémicas / Internet application for medical purposes in chronic patients cared in a Systemic Autoimmune Diseases unit

Objetivo. En los últimos años Internet se ha convertido en una importante herramienta para la búsqueda de información médica, no sólo para los médicos, sino también para los pacientes. Poco se conoce sobre la utilización de la red por parte de los pacientes en España. Nuestro objetivo fue estudiar la frecuencia con la que los pacientes atendidos en nuestra consulta, afectos de diferentes enfermedades autoinmunes crónicas, utilizan Internet como fuente de información médica e identificar los factores asociados con su uso. Métodos. Se pasó un cuestionario sobre la utilización de Internet a los pacientes atendidos en una Unidad de Enfermedades Autoinmunes Sistémicas en un hospital universitario durante tres semanas consecutivas. Resultados. Ciento treinta y ocho pacientes completaron el cuestionario. Ochenta y siete (63%) fueron mujeres. Cincuenta y cuatro pacientes (39,1%) fueron mayores de 55 años. El tiempo medio de evolución de la enfermedad fue 34,2 ± 39,2 meses. El 22% de los encuestados no tenían estudios, el 39% tenía estudios elementales, el 20% estudios medios y el 20% estudios superiores. Cuarenta y dos pacientes (30,4%) utilizaban Internet de forma habitual con cualquier fin. Los factores asociados con la utilización de Internet con fines médicos fueron el utilizar Internet habitualmente (OR: 4,6; IC: 1,1-18,8; p = 0,03) y el tener estudios medios o superiores (estudios superiores: OR: 22,9; IC: 2,6-202,7; p = 0,005; estudios medios: OR: 8,5; IC: 1,2-59,6; p = 0,03). Ochenta y un pacientes (58,7%) expresaron su deseo de que se les facilitara información sobre páginas de Internet de calidad. Conclusiones. En nuestro medio muchos pacientes utilizan Internet con fines médicos, y aún más esperan utilizarlo en un futuro. Es importante ser conscientes de este hecho y facilitar a los pacientes interesados direcciones de páginas web de calidad

Objective. In recent years Internet has become an important tool for medical information search, not only for physicians but also for the patients. Little is known about Internet patient's use in Spain. Our objective was to study the frequency with which patients with different chronic autoimmune diseases cared in our unit use Internet as a source of medical information, and to identify the factors associated with its use. Methods. A survey was carried out on Internet use to patients cared in a teaching hospital Systemic Autoimmune Diseases unit along three consecutive weeks. Results. Hundred thirty-eight patients completed the questionnaire. Eighty-seven (63%) were women. Fifty-four patients (39.1%) were older than 55 years. Mean disease progression was 34.2 ± 39.2 months. 22% of the respondents were uneducated, 39% had elementary education level; 20% had average education level, and 20% had advanced education level. Forty-two patients (30.4%) used regularly Internet for any purpose. Factors associated to Internet use for medical purposes were regular Internet use (OR: 4.6; CI: 1.1-18.8;p = 0.03), and average or advanced educational degree (advanced education: OR: 22.9; CI: 2.6-202.7; p = 0.005; average education: OR: 8.5; CI: 1.2-59.6; p = 0.03). Eighty-one patients (58.7%) expressed their need of information on quality web pages. Conclusions. Many patients use Internet for medical purposes in our environment and even more consider to use it in the future. It is important to be aware of this fact and facilitate information about quality web pages for interested patients

Stimulus correlation and adaptive motion detection using spiking neurons.

Stimulus correlation and adaptive movement detection, among other tasks can be performed with VLSI general-purpose neurons that have controllable steady and transient responses. This paper presents experimental results of simple neural primitives based on the CMOS neuron approach described in [11]. Stimulus correlation experiments illustrate the well defined behavior of the CMOS approach. This basic primitive is used to implement motion detectors with adaptive capabilities that enable it to work efficiently in a wide velocity range.

Caffeine attenuates the action of amsacrine and etoposide in U-937 cells by mechanisms which involve inhibition of RNA synthesis.

Pulse treatments of U-937 human promonocytic leukemia cells with the DNA topoisomerase-II inhibitors 4'-(9-acridynilamino)methanesulfon-m-anisidide (amsacrine, mAMSA) or etoposide (VP-16) caused growth inhibition, G2-arrest, increase in cell size and expression of differentiation markers. All these effects were greatly reduced by the presence of 5-10 mM caffeine. In addition, caffeine partially prevented the increase in the number of topoisomerase-DNA cleavable complexes caused by the topoisomerase inhibitors, as determined by SDS/CIK precipitation assays; it caused chromatin condensation, as determined by flow cytometry assays, and interacted with mAMSA in solution, as suggested by spectrophotometric assays. Pulse treatment with caffeine greatly inhibited RNA synthesis but not DNA or protein synthesis, as indicated by labelled precursor incorporation assays. The transcription inhibitor 5,6-dichloro-I-beta-D-ribofuranosylbenzymidazole reduced the mAMSA- and VP-16-produced growth inhibition in a similar manner. It is concluded that RNA synthesis inhibition is one of the possible mechanisms by which caffeine protects cells from the action of topoisomerase-II inhibitors.

Cellular and humoral reactivity pattern to the mycobacterial heat shock protein HSP65 in adjuvant arthritis susceptible and resistant Wistar rats.

We have analyzed the cellular and humoral immunity to the mycobacterial 65 KDa heat shock protein (hsp65) in a group of Freund's Adjuvant-immunized rats with a limited susceptibility to Adjuvant arthritis. According to the arthritis indices during the period of study (35 days), two different groups of rats could be distinguished; a) autoimmune Adjuvant arthritic rats (AA), and b) Non-arthritic animals (NA), including both rats which did not display any disease symptoms and rats suffering mild transient inflammation. The cellular response to the immunizing agent (Mycobacterium tuberculosis) or the mitogen Concanavalin A was comparable between both groups of rats. However, we detected an impaired cellular response to the individual hsp65 antigen in the animals that did not develop the disease. On the contrary, the level of hsp65-specific antibodies was much higher in NA animals than in AA rats suggesting a protective role for the hsp65 specific antibodies.