1,720,964 research outputs found
A bioinspired stretchable membrane-based compliance sensor
No full textCompliance sensation is a unique feature of the human skin that electronic devices could not mimic via compact and thin form-factor devices. Due to the complex nature of the sensing mechanism, up to now, only high-precision or bulky handheld devices have been used to measure compliance of materials. This also prevents the development of electronic skin that is fully capable of mimicking human skin. Here, we developed a thin sensor that consists of a strain sensor coupled to a pressure sensor and is capable of identifying compliance of touched materials. The sensor can be easily integrated into robotic systems due to its small form factor. Results showed that the sensor is capable of classifying compliance of materials with high sensitivity allowing materials with various compliance to be identified. We integrated the sensor to a robotic finger to demonstrate the capability of the sensor for robotics. Further, the arrayed sensor configuration allows a compliance mapping which can enable humanlike sensations to robotic systems when grasping objects composed of multiple materials of varying compliance. These highly tunable sensors enable robotic systems to handle more advanced and complicated tasks such as classifying touched materials.
A low-power stretchable neuromorphic nerve with proprioceptive feedback
No full textBy relaying neural signals from the motor cortex to muscles, devices for neurorehabilitation can enhance the movement of limbs in which nerves have been damaged as a consequence of injuries affecting the spinal cord or the lower motor neurons. However, conventional neuroprosthetic devices are rigid and power-hungry. Here we report a stretchable neuromorphic implant that restores coordinated and smooth motions in the legs of mice with neurological motor disorders, enabling the animals to kick a ball, walk or run. The neuromorphic implant acts as an artificial efferent nerve by generating electrophysiological signals from excitatory post-synaptic signals and by providing proprioceptive feedback. The device operates at low power (~1/150 that of a typical microprocessor system), and consists of hydrogel electrodes connected to a stretchable transistor incorporating an organic semiconducting nanowire (acting as an artificial synapse), connected via an ion gel to an artificial proprioceptor incorporating a carbon nanotube strain sensor (acting as an artificial muscle spindle). Stretchable electronics with proprioceptive feedback may inspire the further development of advanced neuromorphic devices for neurorehabilitation.
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Development of a novel biosensor for rapid and specific detection of viable «Legionella» bacteria for on-site applications
No full textLegionellosis is a devastating disease worldwide, due to unpredictable outbreaks in man-made water systems. Legionella, the causative agent of this disease, was responsible for more than 30% of water-borne disease outbreaks in the USA between 2001 and 2006. The literature indicates that modern water systems, such as air-conditioning units, showers, hot tubes and industrial refrigeration towers provide optimal growth conditions for Legionella pneumophila (L. pneumophila) and propagate its transmission through aerosol. Transmission to the human host thus occurs through the inhalation of contaminated water droplets. Developing a highly specific, sensitive and rapid biosensor that detects only metabolically active bacteria is a main priority for water quality assessment. In this thesis, we proposed a detection system based on highly specific DNA capture and detector probes targeting the 16s rRNA from pathogenic L. pneumophila using Surface Plasmon Resonance imaging (SPRi). To achieve specific and sensitive detection, probe design and optimal hybridization conditions were implemented.We investigated the performance of the developed biosensor for detection of L. pneumophila in complex environmental samples, particularly those containing protozoa. We demonstrated that the expression level of rRNA is extremely dependent on the environmental conditions. The presence of amoebae with L. pneumophila, especially in nutrition-deprived samples, increased the amount of L. pneumophila 15-fold after one week. Using the developed SPRi detection method, we were also able to successfully detect L. pneumophila within three hours, both in the presence and absence of amoebae in the complex environmental samples obtained from a cooling water tower.Despite advances in miniaturization and automation of biosensors for on-site applications, progress in cutting-edge technologies, especially for monitoring environmental water samples to predict potential outbreaks are still at an early stage of development. Among different fluidic handling systems, digital microfluidics (DMF) has gained much interest. In DMF, as opposed to continuous flow microfluidics, individual droplets are manipulated independently by applying electric potential to an array of electrodes. In this setup, there is no need for external pump or tubing which makes it a great candidate for on-site applications. In order to integrate the developed detection system with a DMF chip, some modifications, such as using fluorescent microscopy and magnetic beads were required. The conception, design and functionality of the advanced DMF device were demonstrated and the simultaneous manipulation of multiple droplets on-chip was confirmed. The various steps of the assays, including magnetic capture, hybridization duration, washing steps, and assay temperature were optimized. We were able to not only to reduce reagent volumes significantly and magnetic beads consumption, but also drop the limit of detection to 1.8 attomoles. Finally, we showed that the multiplex detection for a pathogenic and a non-pathogenic species of Legionella can be achieved by using capture and detector DNA probes for each 16s rRNA target. Taken all together, our results suggest that the developed DMF device combined with the proposed detection system has great potential for rapid, high-throughput, multiplex, and inexpensive on-site detection of pathogens.Dans le monde entier, la légionellose est une maladie aux conséquences néfastes, tout particulièrement en raison de l’augmentation des épidémies incontrôlées au niveau des systèmes de traitement des eaux. La Légionnelle est l’agent infectieux responsable de cette maladie, et qui est également impliquée dans plus de 30% des maladies hydriques aux Etats-Unis entre 2001 et 2006. Les données de la littérature montrent que les systèmes modernes de traitement des eaux, tels que la climatisation, les systèmes de douches, et les tours de refroidissement offrent des conditions optimales de croissance et de propagation de la Legionella pneumophila (L. pneumophila) à travers la formation d’aérosols. De ce fait, la transmission de la légionellose aux humains se produit à travers l’inhalation de gouttelettes d’eau contaminée. L’un de principaux défis de l'évaluation de la qualité de l'eau serait de mettre au point des biocapteurs hautement spécifiques, sensibles et rapides. Dans cette thèse, nous avons mis au point un système SPRi de détection basé sur la capture hautement spécifique de l’ADN et sur le ciblage par sonde de détection spécifique de l’ARNr 16s provenant des L. pneumophila pathogéniques. Afin d’améliorer la spécificité et la sensibilité de détection des pathogènes, nous avons conceptualisé une sonde spécifique et mis en œuvre des conditions optimales d’hybridation. Nous avons donc testé la performance de notre plateforme de détection des L. pneumophila sur des échantillons représentatifs d’un environnement complexe, notamment de part la présence de protozoaires. Ainsi, nous avons démontré que le taux d’expression des ARNr est fortement lié aux conditions environnementales. En mesurant l’expression des ARNr 16s, la présence concomitante d’amibe et de L. pneumophila, tout particulièrement dans les échantillons en carence de substance nutritive, augmente de manière significative la quantité de L. pneumophila après une semaine. Nous avons également détecté, par l’utilisation de notre méthode SPRi, les L. pneumophila en moins de 3 heures, en présence ou en absence d’amibe dans les échantillons des tours de refroidissement. Malgré, les avancées en miniaturisation et en automatisation des biosenseurs pour l’utilisation in situ, il reste encore plusieurs défis à relever notamment dans l’analyse des échantillons d’eau d’origine environnementale afin de prédire au mieux les risques potentiels d’épidémies. Les dispositifs à microfluides digitaux (DMF) sont des candidats très prometteurs en comparaison au reste des systèmes de manipulation fluidiques. De plus, à l’opposé des dispositifs microfluidiques à flux continu, le dispositif DMF permet de manipuler de manière indépendante des gouttelettes individuelles par l’application de potentiel électrique à un réseau d’électrode. Notre appareillage ne requiert aucune pompe externe ou tubes, ce qui le rend utile pour des applications sur place. Aussi, afin d’intégrer ce système de détection à la puce DMF, des modifications ont été apportées telles que l’utilisation de billes magnétiques fluorescentes. Les différentes étapes de l’analyse, incluant la capture magnétique, la durée d’hybridation, les étapes de lavage et la température optimale ont été optimisées. Le volume des réactifs et la quantité de billes magnétiques ont été réduit considérablement. De plus, le seuil de détection a été baissé à 1.8 attomoles. Finalement, nous avons démontré que notre système détecte spécifiquement l’ARN 16s. Nous avançons que ce système détient un énorme potentiel de détection multiplexe, rapide, à haut débit et peu coûteux pour divers pathogènes, et ce à partir de très petites quantités d’échantillons et de réactifs
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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