1,720,958 research outputs found
Effect of extraction conditions on antioxidant activities of
No full textThis research aims to obtain the Xanthium strumarium sprouts extract with the most potent antioxidant activities. The single-factor experiments were used to extract. Factors of extraction, including temperatures (40, 50, 60, and 70°C), time (6, 8, 10, 20, and 30 minutes), and % ethanol in solvent (40, 50, 60, and 70 % EtOH), were applied in the ultrasonic assist extraction of 40°C oven-dried Xanthium strumarium sprouts 1 gram in 25 mL of solvent. Extraction yield (% yield) and % inhibition of active radical DPPH and ABTS were determined, and the correlation to varied factors was analyzed using a statistical program (SPSS). The results showed that, at low temperatures, it would give a low % yield but not affect antioxidant activities. The longer extraction time did not provide a different % yield than the shorter one. The extraction yield is a little better when 50% ethanol is used in water as a solvent and does not affect antioxidant activities. As they observe, we can conclude that the antioxidant activities of extracts do not depend on temperature, time, or % EtOH in solvents. The % inhibition of ABTS radicals is higher than that of DPPH radicals in all experiments, and it can be relied on that the active components in this extract are more polar and favorable to solute in water than EtOH
Trace Elements in Indoor Dust Exposure from Child Development Centers and Health Risk Assessment in Haze and Industrial Areas, Thailand
No full textThis study aimed to examine trace element concentrations in indoor dust and evaluate health risks in child development centers in haze and industrial areas of Thailand from November 2023 to April 2024. The samples were extracted using a microwave oven and analyzed via ICP-OES. The finding indicated that the levels of As, Cr, Pb, V, Fe, Mn, and Zn in the dust from child development centers in the industrial area were significantly higher than those in the haze area (p < 0.05). The presence of trace element contaminants in indoor dust is indicative of anthropogenic sources. Cd and Zn in both areas have shown significantly elevated risks, according to the probable ecological risk factor. Source apportionment identified traffic, road dust, and biomass combustion as the principal sources of pollution in the haze area, while traffic and combustion activities were significant in the industrial area. Non-carcinogenic risk assessments for children exposed to As, Pb, Cu, and Cr revealed potential health risks (HI > 1). Furthermore, the total cancer risk (TCR) linked to As, Cr, and Ni is considered acceptable within the criteria of 10−6 to 10−4. However, long-term exposure may increase the risk of cancer in children
Indoor PM<sub>2.5</sub>and its Polycyclic Aromatic Hydrocarbons in Relation with Incense Burning
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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
Risk Assessment of Heavy Metals in Sediment Samples from the Mae Chaem River, Chiang Mai, Thailand
No full textHeavy metals are significant environmental pollutants that are recognized as posing a potential health hazard to human beings. We investigated the concentrations of the heavy metals As, Cd, Cr, Cu, Ni, Pb, and Zn in surface sediments collected from the Mae Chaem River in Chiang Mai, Thailand, during the dry season in 2021. The mean concentrations of heavy metals in sediments were, in decreasing order, Zn > Cr > As > Pb > Ni > Cu > Cd. The mean values of As, Cd, Cr, and Cu were determined to be 32.5 ± 18.3, 0.33 ± 0.07, 45.8 ± 11.9, and 21.9 ± 7.42 mg Kg−1, respectively. These levels are higher than their standard levels in Thailand, namely 10.0, 0.16, 45.5, and 21.5 mg Kg−1, respectively. Principal component analysis (PCA) revealed that the primary origins of heavy metal contamination are predominantly attributed to residential settlements and agricultural areas. The hazard quotient (HQ) was used to estimate the non-carcinogenic risk of exposure to heavy-metal-bound surface sediments for both children and adults. The results showed that the HQ values for both groups were less than 1.0 (HQ −6) based on the lifetime cancer risk (LCR). However, the LCR values of As and Cr were 5.3 × 10−6 and 2.5 × 10−6, respectively, demonstrating the most elevated LCR among the hazardous metals in terms of children’s exposure. Therefore, it is possible that children living in agricultural areas and participating in activities around the study area may be exposed to elevated concentrations of As and Cr
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
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