1,720,954 research outputs found
A Millifluidic Device with Embedded Cross-Linked Enzyme Aggregates for Degradation of H<sub>2</sub>O<sub>2</sub>
No full textMillifluidic devices decorated with
enzymes have been used for enzymatic reactions in continuous processes,
but low enzymatic activity and enzyme leaching remain as challenges.
Herein, we develop a strategy to embed cross-linked enzyme aggregates
(CLEAs) on the surfaces of millifluidic devices to achieve higher
enzymatic activity and better stability. Catalase was chosen as a
model enzyme to degrade H2O2 in wastewater samples.
First, CLEA of catalase (153 ± 10 nm) was formed by simultaneous
precipitation and cross-linking with 25.0 wt % acetonitrile containing
0.025 wt % glutaraldehyde in a millifluidic device. To immobilize
CLEA, we first swell a piece of plastic tubing by using 5.0 wt % acetonitrile
and then immerse it in an aqueous solution with 5.0 wt % (3-aminopropyl)triethoxysilane
(APTES) and 5.0 wt % dextran polyaldehyde (DPA) subsequently. After
CLEA is absorbed inside the expanded polymer network of the tubing,
the tubing is tightened by using a vacuum to secure the immobilized
CLEA. The millifluidic device decorated with CLEA of catalase has
total activity of 660 U for degradation of H2O2, and it shows good stability under a flow rate of 200 μL/min.
The tubing can be used to degrade 0.1 wt % H2O2 solution continuously for 3 h or remove 2 wt % residual H2O2 in wastewater for 2 h. The technique is general enough
and can be applied to other types of enzymes for continuous enzymatic
reactions
Immobilization of Enzymes on Flexible Tubing Surfaces for Continuous Bioassays
No full textImmobilized
enzymes can be used to catalyze biochemical reactions
in a batch process, however, it is more difficult to use them in a
continuous process. Herein, we develop an enzyme immobilization technique
for flexible tubing surfaces, which can be used to catalyze biochemical
reactions in a continuous process. In this technique, the tubing is
first treated with (3-aminopropyl)triethoxysilane at 50 °C and
baked at 100 °C in vacuum to form a network of reactive amine
functional group on the inner tubing surface. Subsequently, dextran
polyaldehyde, a polymeric cross-linker, is used to immobilize crude
protease extract and catalase for hydrolyzing casein and degrading
H2O2, respectively, in a continuous process.
The immobilized proteases are highly stable even after a long-term
storage at 4 °C. After 12 weeks of storage, 90% of the original
protease activity can be preserved. Meanwhile, the immobilized catalase
is able to degrade 0.1% H2O2 solution flowing
at 5 μL/min. The immobilization technique is potentially useful
for bioassays and industrial wastewater treatments when continuous
processes are preferred
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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