1,720,966 research outputs found
A conformal nano-adhesive via initiated chemical vapor deposition for microfluidic devices
No full textA novel high-strength nano-adhesive is demonstrated for fabricating nano-and microfluidic devices. While the traditional plasma sealing methods are specific for sealing glass to poly(dimethylsiloxane) (PDMS), the new method is compatible with a wide variety of polymeric and inorganic materials, including flexible substrates. Additionally, the traditional method requires that sealing occur within minutes after the plasma treatment. In contrast, the individual parts treated with the nano-adhesive could be aged for at least three months prior to joining with no measurable deterioration of post-cure adhesive strength. The nano-adhesive is comprised of a complementary pair of polymeric nanolayers. An epoxy-containing polymer, poly(glycidyl methacrylate) (PGMA) was grown via initiated chemical vapor deposition (iCVD) on the substrate containing the channels. A plasma polymerized polyallylamine (PAAm) layer was grown on the opposing flat surface. Both CVD monomers are commercially available. The PGMA nano-adhesive layer displayed conformal coverage over the channels and was firmly tethered to the substrate. Contacting the complementary PGMA and PAAm surfaces, followed by curing at 70 degrees C, resulted in nano-and micro-channel structures. The formation of the covalent tethers between the complementary surfaces produces no gaseous by-products which would need to outgas. The nano-adhesive layers did not flow significantly as a result of curing, allowing the cross-sectional profile of the channel to be maintained. This enabled fabrication of channels with widths as small as 200 nm. Seals able to withstand > 50 psia were fabricated employing many types of substrates, including silicon wafer, glass, quartz, PDMS, polystyrene petri dishes, poly(ethylene terephthalate) (PET), polycarbonate (PC), and poly(tetrafluoro ethylene) (PTFE).This research was supported by, or supported in part by, the US
Army through the Institute for Soldier Nanotechnologies, under
Contract DAAD-19-02-0002 with the US Army Research Office
Patterning Nanodomains with Orthogonal Functionalities: Solventless Synthesis of Self-Sorting Surfaces
No full textA simple method to fabricate a multifunctional patterned platform on the nanometer scale is demonstrated. The platform contains two reactive functional groups on the surface: one is an acetylene group which can be functionalized via click chemistry, and the other is an amine group which can also be functionalized by classic carbodiimide chemistry with N-hydroxysuccinimide (NHS). The click-active and amine surface could be obtained from polymer coating of poly(propargyl methacrylate) (PPMA) via initiated chemical vapor deposition (iCVD) and poly(allylamine) (PAAm) via a plasma polymerization process, respectively, utilizing commercially available monomers. A capillary force lithography (CFL) process was applied on a stacked film of a PPMA layer on PAAm, and CFL could selectively pattern PPMA maintaining the bottom PAAm layer intact, which completes the multifunctional nanopatterns. The minimum feature size of this nanopattern was 110 nm. The entire fabrication process is solventless and low temperature which can minimize the loss of functionalities. The click and NHS reactions are highly orthogonal to each other so that nonspecific immobilization can be minimized. These advantageous characteristics enable the covalent functionalization of two independent components in a one-pot functionalization process in self-recognized way. The one-pot orthogonal functionalization was performed in an aqueous solution at room temperature, which is biocompatible. Considering the versatility and generality of the reactions used here, we believe this platform can be easily extended to various biodevice applications.This research was supported by the U.S.
Army through the Institute for Soldier Nanotechnologies, under
Contract DAAD-19-02-D-0002 with the U.S. Army Research
Office
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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