1,721,053 research outputs found
Analysis of Dielectric Microbead Detection by Impedance Spectroscopy with Nanoribbons
No full textWe present a quantitative numerical analysis of dielectric microbead detection experiments with nanoribbons operated in the AC small signal regime. To this purpose, a comprehensive model of nanoribbon operation in electrolyte environment and with DC/AC signals is extended to include the effect of site-binding charges in DC, transient and AC conditions. The model is calibrated against DC measurements and pH-transients data from the literature. The impact of the microfluidic chamber size, the interconnects and the site-binding charge is investigated. The calibrated model suggests that the impedance response to micron-sized beads cannot be explained without also taking into account the bead surface charge
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
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
Multi-Wire Tri-Gate Silicon Nanowires Reaching Milli-pH Unit Resolution in One Micron Square Footprint
Full text linkThe signal-to-noise ratio of planar ISFET pH sensors deteriorates when reducing the area occupied by the device, thus hampering the scalability of on-chip analytical systems which detect the DNA polymerase through pH measurements. Top-down nano-sized tri-gate transistors, such as silicon nanowires, are designed for high performance solid-state circuits thanks to their superior properties of voltage-to-current transduction, which can be advantageously exploited for pH sensing. A systematic study is carried out on rectangular-shaped nanowires developed in a complementary metal-oxide-semiconductor (CMOS)-compatible technology, showing that reducing the width of the devices below a few hundreds of nanometers leads to higher charge sensitivity. Moreover, devices composed of several wires in parallel further increase the exposed surface per unit footprint area, thus maximizing the signal-to-noise ratio. This technology allows a sub milli-pH unit resolution with a sensor footprint of about 1 μm2, exceeding the performance of previously reported studies on silicon nanowires by two orders of magnitude
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
Combining Hydrodynamic and Electrokinetic Forces for Particle Manipulation in Bioanalytical Microsystems
No full textThis Thesis introduces technologies for particle manipulation in bioanalytics, designed to advance integrative biology leveraging biomarker quantification. Bioanalytical information is essential for uncovering mechanisms and pathways, particularly in noncommunicable diseases, often lacking individualized therapy. Despite the availability of various tools for purifying and characterizing analytes, current methods may be unsuitable for downstream analysis or inaccessible due to high costs and the need for specialized personnel.
Microfluidics offers solutions to these challenges via innovative bioanalytical systems. This work proposes microsystems combining electrokinetic and hydrodynamic forces for versatile particle manipulation. Hydrodynamic methods allow for mechanical size-based immobilization or deflection of bioparticles, while adding electrical forces enables contactless manipulation, tunable in real time.
The Thesis presents microfluidic devices with active or passive micro-features, deploying various shapes and configurations. For dielectrophoretic (DEP) applications, three-dimensional electrodes spanning the height of microchannels allow for larger volumetric capacities and higher sample processing throughput. Addressing microfabrication challenges and optimizing SU-8 photolithography enabled the integration of metal-coated posts, passive obstacles, and traps.
This work focuses on two key aspects of bioanalytics: sample purification and bioassay automation. For sample purification, passive deterministic lateral displacement (DLD) was implemented to isolate large, fragile bone marrow (BM) cells at processing times comparable to fluorescence-activated cell sorting (FACS) while preserving viability. This system retrieved mature BM cells at high purity, representing the first solution for their non-destructive size-based separation compatible with downstream analysis. Additionally, DEP-enhanced DLD devices showed improved capabilities to sort submicrometer particles. Teardrop-shaped posts were introduced to reduce the DEP-DLD critical size by spatially shaping the electric field, a patented solution.
To advance bioassay automation, DEP modules were developed to handle beads functionalized with capture antibodies for protein quantification, supporting sequential operations including incubation, release, and clustering. DEP-DLD enabled robust spatial multiplexing to test diverse markers on differently-sized beads. To obviate the need for active pumping and serial injections, a hydrodynamic self-contained platform was developed, exploiting capillarity and paper modules storing reagents within a fully automatic bead-based multimarker assay system, requiring only sample injection by the user. This novel configuration pairs microfluidics with paper components independently adjustable to tune the assay flow and reagent release. This platform quantified kidney function biomarkers from one microliter of mouse urine or plasma within twenty minutes, effectively replicating standard ELISA results.
In conclusion, this Thesis advances a design space combining three-dimensional active and passive features within microfluidics to control particle trajectories in continuous flow. These technologies offer versatile, easy-to-use solutions with a high degree of automation, minimizing extensive sample preparation off-chip. Implementing these methods for novel bioanalytical applications opens new possibilities for biological discoveries and healthcare.CLS
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