1,720,962 research outputs found
Leaching of Potentially Toxic Metals (PTMs) from Two Nigerian Clays and Related Clay Pottery Used Locally as Foodwares
No full textPhytochemical Screening and Evaluation of the Antioxidant Activity of Ficus capreifolia Leaf Extract via in-vitro Models
Get PDFAims: To carry out preliminary phytochemical screening and determine the antioxidant ability of Ficus capreifolia leaf extract.
Study Design: The study was designed to evaluate the phytochemical profile of Ficus capreifolia leaf and the potential antioxidant activity and comparing to reference antioxidant vitamin C.
Place and Duration of Study: The research was done in the Department of Chemistry, Rivers State University from May to August 2016.
Methodology: The extract was screened for the presence of some phytochemicals. Thereafter, the antioxidant potential was determined by assessing the hydrogen peroxide scavenging ability, hydroxyl radical scavenging activity and ferrous ion reducing ability and comparing them to the corresponding ability of vitamin C.
Results: Phytochemicals detected include tannins, carotenoids, alkaloids, flavonoids, steroids, cardiac glycosides and polyphenols. The extract also scavenged hydrogen peroxide, hydroxyl radicals and also reduced ferrous ions significantly when compared to vitamin C.
Conclusion: The leaf extract exhibited significant antioxidant activities which could be ascribed to antioxidant phytochemicals such as flavonoids, polyphenols which were detected. This corroborates the reported traditional use of the plant and can be further exploited pharmacologically
Phytochemical Screening and Evaluation of the Antioxidant Activity of Ficus capreifolia Leaf Extract via in-vitro Models
No full textEvaluation of the Anti-lipid Peroxidative Potential of Ficus capreifolia Leaf Extract Using In-vitro Models
No full textDetermination and Risk Assessment of Heavy Metals Concentrations collected from Indoor houses at Lagos State of Nigeria
Get PDFThe aim of this study is to determine the levels of selected heavy metals (As, Pb, Zn, Cu and Cr) at 60 homes from the 20 local governments in Lagos State, Nigeria. Approval was sought from respective residential landlords and occupants of the sampledcommunities. Three dust samples were collected from each local government. A total of 60 dust samples were collected andlabelled according to the first three letters of each Local government. Indoor dust samples from households (furniture, containerbags, window slides, ceiling fan and standing fan) were collected using soft paint brushes. 0.5g of the homogenized mixture wasmeasured in triplicate labelled 1, 2 and 3 in different boiling tubes for digestion process. Each triplicate samples were digestedusing aqua regia for 1 hour at a temperature of about 100 degree celcius. Heavy metal concentrations were determined usingAgilent Technologies 4210 MP-AES Atomic Absorption Spectrometer (AAS). The concentration of heavy metals in the indoor dustwere dominated by Arsenic with an average concentration of 57.76-111.93 mg/kg followed Lead 13.81-116.60 mg/kg, Zinc 22.73-224.2 mg/kg, Copper 8.27-228.75 mg/kg and Chromium with concentration of 2.53-22.60 mg/kg respectively. The concentrationsof heavy metal in the areas investigated followed the order: Ar>Pb>Zn>Cu>Cr. The exposure dose was also estimated throughingestion, inhalation and dermal contacts, and the exposure route was highest for ingestion pathway. The health risk (carcinogenic and non-carcinogenic) of these heavy metals were assessed based on the United States Environmental ProtectionAgency health risk models. The estimated values were compared to standard guidelines and human health limits by the UnitedStates Environmental Protection Agency, USEPA and California Environmental Protection Agency, Ca/EPA. For noncarcinogenic risk, the hazard index values for all the studied metals were lower than the safe level of 1. The Total Lifetime Cancer Risk for adults and children were below the limit (1x10-6– 1x10-4) as standardized by USEPA except in children which was slightly higher than the permissible limit in two local government areas; (Shomolu L.G.A 1.03x10-4) and (Lagos Mainland 1.02x10-4). This indicates that the risk of carcinogenic effect occurring is likely in children with exposure to arseni
Effects of Anthropogenic Activities on the Surface Water Quality of Idim Esiere Ebom Stream in Calabar South Lga, Cross River State, of Nigeria
Get PDFThe Idim Esiere Ebom Stream is a major source of freshwater in Garden street, Calabar South LGA of Cross River State, Nigeria, as well as a spring of potable water to the residents. However, there is the dearth of scientific information on the water quality of the stream; Thus, the need to evaluate its water quality. To this end, the effects of the physicochemical characteristics of the water quality and some heavy metals of the surface water and sediments of the Idim Esiere Ebom stream were studied. In this study, samples of the surface water and sediments were collected from 5 different stations of the stream monthly for 6 months (March-August) representing early wet (EW) season (March to May) and Peak wet (PW) season (June to August). The mean levels of the spatial and temporal distribution of Physicochemical parameters (pH, Temperature, Dissolved Oxygen, Salinity, Total dissolved Solids, Electric conductivity, Turbidity, Biochemical Oxygen Demand) of surface water and heavy metals (Iron, Copper, Lead, Chromium, Cadmium and Nickel) of the surface water and sediments were determined. The results from the analysis were compared with national and international standards. From the results obtained, it was observed that levels of most physicochemical characteristics and heavy metals exceeded the permissible limits. In conclusion, the anthropogenic activities into the stream has an impact in some stations of the stream
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
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