1,720,957 research outputs found
Isolation and Identification of Heavy Metal Tolerant Soil Fungi from the Ussangoda Serpentine
Get PDF‘Serpentine’ soils derived from certain ultramafic rocks occur throughout the globe. These soils are high in Fe and Mg concentrations; consist heavy metals such as Ni, Cr, Cd, and Co; are nutrient poor and ionically imbalanced for plant growth. Serpentine life forms typically contain specialised physiological mechanisms that allow tolerate the adverse chemical conditions imposed by the substrate. Heavy metal hyper-accumulating and/or tolerating plants and micro-organisms from serpentines represent a rare and valuable biological resource. These unique habitats and their exceptional species must be characterised and conserved. This study aimed to isolate and identify heavy metal tolerating soil microorganisms from the Ussangoda serpentine site (Hambantota District). Soil samples from ten locations within the serpentine area (to represent various aspects of the terrain such as flat plain, shrubby patches in the middle, and periphery) were collected and analysed separately. Low soil organic matter (1.02% to 1.71%) and moisture (highest being 1.21%) contents were observed with soil pH ranging between 5.47-8.46 (majority of the samples being acidic). Metal analysis of soil Cr, Fe and Cu indicated 0.1-0.4 ppm, 10.4-19.0 ppm and 5 ppm-11 ppm, respectively. Serpentine soil microorganisms were isolated using standard methods. Twenty fungal isolates and twelve bacterial isolates were obtained by the preliminary study. To investigate their tolerance of heavy metals, all twenty fungal isolates were grown in PDA media containing different concentrations of selected metal solutions (Ni(NO3)2 and CuSO4(H2O)5). Nine out of twenty fungal isolates survived up to 800 µg/mL CuSO4(H2O)5 and four isolates tolerated up to 2,000 µg/mL Ni(NO3)2. Based on the highest tolerance shown to the tested metals, two fungal isolates were selected and identified using molecular techniques. Genomic DNA extracts of two fungal isolates were sequenced using Internal Transcribed Spacer (ITS) region reverse and forward primers. From the sequences, the two isolates were identified as Aspergillus terreus and Gongronella butleri. A. terreus has many previous records on heavy metal tolerance and being used in cleaning up industrial effluents contaminated with certain metals. G. butleri is known to produce the amino-polysaccharide chitosan which is a metal chelator and it may be one reason for the observed heavy metal tolerance capacity of the fungus. This study has provided evidence-based information which may be useful in developing green technologies to remediate soils contaminated with heavy metals. The results also reiterate the importance of conserving serpentine habitats that harbor unique species and communities of organisms. Keywords: Serpentine, Ussangoda, Heavy-metal tolerant fung
Antioxidant and Sun Protection Capacity of Ceylon Black Tea Brew Based on Tea Grades and Manufacturing Technique
Get PDFSri Lankan-produced Ceylon black tea is well-known for its superior leaves and intense flavour. Ceylon black tea has been a recent interest for value-added products such as food/beverages and even cosmetics. However, the extraction of important bio chemicals with their bioactivities can be different among tea grades and their manufacturing process. The traditional orthodox technique involves hand-plucking, withering, rolling, and oxidation. The intense machinery process starts with pre-conditioning in a rotor vane followed by processing in the main Crush Tear Curl (CTC) tea machine. The study included six Ceylon black tea grades sourced from Sri Lanka’s high-grown agro-climacteric elevations, each manufactured in two major techniques: orthodox and rotorvane-CTC (Broken Orange Pekoe (BOP), Broken Orange Pekoe Fanning’s 1 (BOPF), Broken Orange Pekoe Special (BOPsp), Fanning’s 1 (FNGS), Dust (D) and Dust 1 (D1)). Black Tea Brew (BTB) of each grade was tested for antioxidant potential: Total Phenol Content (TPC) as Gallic Acid Equivalent (GAE), Total Flavonoid Content (TFC) as Rutin Equivalent (RE), and DPPH free-radical scavenging percentage (DPPHfrs%) followed by in-vitro Sun Protection Factor (SPF). The TPC, TFC, DPPHfrs%, and SPF of black tea grades in the rotorvane-CTC technique ranged from 0.670 g/L to 1.011 g/L, 0.503 g/L to 0.692 g/L, 44.762% to 66.219% and 31 to 40 respectively. The black tea grades in the orthodox technique showed TPC, TFC, DPPHfrs%, and SPF values ranging from 0.792 g/L to 1.299 g/L, 0.385 g/L to 0.777 g/L, 60.784% to 71.821% and 29 to 44 respectively. The highest TPC, TFC, and SPF were observed in dust grade manufactured in orthodox technique. Further, the highest DPPHfrs% was observed in BOPsp grade in the orthodox technique. The carefully handled steps during the traditional method preserve more of the natural antioxidants of tea while the dust range produces finer particles facilitating better brewing. Ceylon black tea has antioxidant and sun protection capacities that can be beneficial for both gut and skin health hence possesses the potential for innovative products such as beverages, beauty teas, and cosmetics. The high bioactivity of the Ceylon black tea dust range, specifically manufactured in traditional orthodox technique, provides an economical opportunity for value-added production that can be introduced to the global market. The current study emphasizes the importance of considering the manufacturing technique of tea grades when incorporating them into value-added beverages or cosmetics to yield highly efficient extraction of different biochemicals and bioactivities as per the requirement of the end product.
Keywords: Ceylon black tea, Orthodox tea, Rotorvane CTC tea, Antioxidant capacity, Sun protection facto
In-vitro Antioxidant, Sun Protection, Anti-inflammatory and Antibacterial Properties of F. leucopyrus, O. octandra and H. speciosa
Get PDFRich biodiversity and strong ethnopharmacological traditional knowledge in Sri Lanka provide an opportunity to utilize highly potential medicinal plant resources for sustainable products extending from pharmacological, food/beverages to cosmetic innovation. Flueggea leucopyrus, Osbeckia octandra, and Hellenia speciosa have been a research focus due to their medicinal benefits according to ethnopharmacology. The current study investigates the beneficial bioactivities of F. leucopyrus, O. octandra, and H. speciosa in terms of their antioxidant, in-vitro sun protection, and anti-inflammatory capacities, followed by antimicrobial activity in a range of extractions. The plant leaf water, glycerine, and ethanol extracts were subjected to antioxidant assays: Total Phenol Content (TPC) as Gallic Acid Equivalent (GAE), Total Flavonoid Content (TFC) as Rutin Equivalent (RE), and DPPH free-radical scavenging percentage (DPPHfrs%) followed by in-vitro Sun Protection Factor (SPF) and egg-albumin anti-coagulation effect for in-vitro Anti-Inflammatory percentage (AI%). The antibacterial activities against Staphylococcus aureus and Pseudomonas aureoginosa strains were tested for water and ethanol extracts of the medicinal plants using disk diffusion and Resazurin assays. The TPC, TFC, and DPPHfrs% of F. leucopyrus ranged from 0.154 g/L to 0.852 g/L, 0.009 g/L to 0.455 g/L and 84.349% to 91.713%, while O. octandra ranging from 0.131 g/L to 1.113 g/L, 0.008 g/L to 0.160 g/L and 79.607% to 92.387% respectively. H. speciosa showed TPC, TFC, and DPPHfrs% ranging from 0.010 g/L to 3.024 g/L, 0.002 g/L to 0.410 g/L and 26.388% to 57.716% respectively. The SPF of F. leucopyrus, O. octandra, and H. speciosa, ranged from 33 to 40, 19 to 40, and 6 to 34 respectively. AI% of F. leucopyrus, O. octandra, and H. speciosa followed 9.037% and 11.940%, 8.418% and 11.852%, 12.515% and 12.000% respectively (water and ethanol extracts respectively). Crude ethanolic leaf extracts of F. leucopyrus and H. speciosa in a higher concentration of 50 mg/mL showed antibacterial activity against S. aureus. Thus, the current plant selection of F. leucopyrus, O. octandra, and H. speciosa can be considered as high potential resources for sustainable products with consideration on the extraction protocols as they can brighten, heal, and hydrate skin and body.
Keywords: Medicinal plants, Antioxidant capacity, Sun protection factor, Anti-inflammatory capacity, Antibacterial activit
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
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