1,721,170 research outputs found
Ammonia Capture in Rhodium(II)-Based Metal–Organic Polyhedra via Synergistic Coordinative and H‑Bonding Interactions
No full textAmmonia (NH3) is among the world’s
most widely
produced bulk chemicals, given its extensive use in diverse sectors
such as agriculture; however, it poses environmental and health risks
at low concentrations. Therefore, there is a need for developing new
technologies and materials to capture and store ammonia safely. Herein,
we report for the first time the use of metal–organic polyhedra
(MOPs) as ammonia adsorbents. We evaluated three different rhodium-based
MOPs: [Rh2(bdc)2]12 (where bdc is
1,3-benzene dicarboxylate); one functionalized with hydroxyl groups
at its outer surface [Rh2(OH-bdc)2]12 (where OH-bdc is 5-hydroxy-1,3-benzene dicarboxylate); and one decorated
with aliphatic alkoxide chains at its outer surface [Rh2(C12O-bdc)2]12 (where C12O-bdc is 5-dodecoxybenzene-1,3-benzene dicarboxylate). Ammonia-adsorption
experiments revealed that all three Rh-MOPs strongly interact with
ammonia, with uptake capacities exceeding 10 mmol/gMOP.
Furthermore, computational and experimental data showed that the mechanism
of the interaction between Rh-MOPs and ammonia proceeds through a
first step of coordination of NH3 to the axial site of
the Rh(II) paddlewheel cluster, which triggers the adsorption of additional
NH3 molecules through H-bonding interaction. This unique
mechanism creates H-bonded clusters of NH3 on each Rh(II)
axial site, which accounts for the high NH3 uptake capacity
of Rh-MOPs. Rh-MOPs can be regenerated through their immersion in
acidic water, and upon activation, their ammonia uptake can be recovered
for at least three cycles. Our findings demonstrate that MOPs can
be used as porous hosts to capture corrosive molecules like ammonia,
and that their surface functionalization can enhance the ammonia uptake
performance
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
Integration of Metal–Organic Polyhedra onto a Nanophotonic Sensor for Real-Time Detection of Nitrogenous Organic Pollutants in Water
No full textThe grave health
and environmental consequences of water
pollution
demand new tools, including new sensing technologies, for the immediate
detection of contaminants in situ. Herein, we report the integration
of metal–organic cages or polyhedra (MOCs/MOPs) within a nanophotonic
sensor for the rapid, direct, and real-time detection of small (<500
Da) pollutant molecules in water. The sensor, a bimodal waveguide
silicon interferometer incorporating Rh(II)-based MOPs as specific
chemical receptors, does not require sample pretreatment and enables
minimal expenditure of time and reagents. We validated our sensor
for the detection of two common pollutants: the industrial corrosion
inhibitor 1,2,3-benzotriazole (BTA) and the systemic insecticide imidacloprid
(IMD). The sensor offers a fast time-to-result response (15 min),
high sensitivity, and high accuracy. The limit of detection (LOD)
in tap water for BTA is 0.068 μg/mL and for IMD, 0.107 μg/mL,
both of which are below the corresponding toxicity thresholds defined
by the European Chemicals Agency (ECHA). By combining innovative chemical
molecular receptors such as MOPs with state-of-the-art photonic sensing
technologies, our research opens the path to implement competitive
sensor devices for in situ environmental monitoring
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
- …
