1,720,968 research outputs found
Green pigment hybrid of natural melanin and cellulose nanofibers for sustainable UV-shielding and antioxidant activity
No full textThe present work reports on a sustainable hybrid pigment obtained from a combination of melanin nanoparticles (MNPs) from the cuttlefish Sepia pharaonis and cellulose nanofibers (CNFs) from the sea squirt Pyura chilensis. The characterization of the cellulose nanofiber–melanin nanoparticle (CNF-MNP) hybrid was carried out by FTIR, XRD, DLS, FESEM and EDS analyses confirming that the two sources had been successfully combined, with some degree of crystalline disruption of cellulose. DLS characterisation of the hybrid showed its uniform hydrodynamic size around ~300 nm. UV–Vis spectroscopy illustrated its good and stable absorbance in the 200–400 nm region, indicating an efficient capacity for blocking ultraviolet radiation. When added to an emulsion formulation at 0.5 % (w/v) dosage, the CNF-MNP hybrid produced a high Sun Protection Factor (SPF) of 26.6 ± 2.6, compared to formulations containing only CNFs (SPF 12.9 ± 1.2) or MNP (SPF 13.7 ± 1.3), or to the blank base (SPF 5.7 ± 0.6). Moreover, the CNF-MNP hybrid demonstrated a concentration-dependent antioxidant activity by DPPH assay (31.2 % inhibition at 1 mg mL 1), suggesting a free radical scavenging potential and a synergistic effect of CNFs and MNPs. Finally, cytotoxicity tests, using MTT assay on Hu02 and Vero cells, indicated that the CNF-MNP hybrid is highly biocompatible at low concentrations (>90 % cell viability at 1 μg mL 1) and >50 % cell viability at 1 mg mL 1. In summary, the proposed CNF-MNP hybrid represents a novel sustainable and multifunctional material thet can be effectively applied as sunscreen product, providing UV protection ability and antioxidant properties, and can be considered a promising future candidate for bio-based cosmetic products
Estimation of carbon pools in the biomass and soil of mangrove forests in Sirik Azini creek, Hormozgan province (Iran)
Full text linkDespite the increasing interest in mangroves as one of the most carbon-rich ecosystems, arid mangroves are still poorly investigated. We aimed to improve the knowledge of biomass and soil carbon sequestration for an arid mangrove forest located at the Azini creek, Sirik, Hormozgan Province (Iran). We investigated the biomass and organic carbon stored in the above and belowground biomass for three different regions selected based on the composition of the principal species: (1) Avicennia marina, (2) mixed forest of A. marina and Rhizophora mucronata, and (3) R. mucronata. Topsoil organic carbon storage to 30 cm depth was also estimated for each analyzed area. Biomass carbon storage, considering both aboveground (AGB) and belowground biomass (BGB), was significantly different between the cover areas. Overall, the mean forest biomass (MFB) was 283.1 ± 89 Mg C ha−1 with a mean C stored in the biomass of 128.9 ± 59 Mg C ha−1. Although pure Rhizophora stand showed the lowest value of above and below tree carbon (AGC + BGC); 17.6 ± 1.9 Mg C ha−1), soil organic carbon stock in sites under Rhizophora spp. was significantly higher than in the site with pure stand of Avicennia spp. Overall, forest soil stored the highest proportion of Sirik mangrove ecosystem organic carbon (59%), with a mean value of 188.3 ± 27 Mg C ha−1. These results will contribute to broaden the knowledge and the dataset available, reducing the uncertainties related to estimates and modeling of carbon pools in arid mangrove ecosystem, which also represent an important climatic threshold of mangrove worldwide distribution
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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