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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 374 journals)
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Journal of Science (JSc)
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  This is an Open Access Journal Open Access journal
ISSN (Online) 2602-9030
Published by Sri Lanka Journals Online Homepage  [71 journals]
  • Comparative adsorption study of mango (Mangifera indica) leaves and neem
           (Azadirachta indica) leaves, as an adsorbent for dye removal

    • Abstract: The study attempted to evaluate and compare the adsorption capacity (Methylene Blue removal) of non-conventional adsorbents prepared from Neem (Azadirachta indica) leaf and Mango (Mangifera Indica) leaf and Langmuir model or Freundlich model were analyzed. The leaves from Neem and Mango were collected, cleaned, dried (115°C) and powdered. The physiochemical properties were studied. Methylene blue dye was used as the pollutant since it is a frequently used dye for adsorption studies. A series of batch experiments were carried to evaluate the adsorption capacity of Neem leaf adsorbent and mango leaf adsorbent with different dosages and different initial adsorbate concentrations (100, 150, 200 and 250 mg/L). Neem leaf showed the highest adsorption capacity of 83%. The adsorption capacity of the Mango leaves was around 79%. Adsorbent dose and adsorption rate have a positive relation. Adsorption rate increases with adsorbent dose and decreases with increases of adsorbate initial concentration. Langmuir isotherm showed a high coefficient of determination. Both Langmuir separation factor (RL) and Freundlich constant (nF) suggest the favorable adsorption of the dye onto the adsorbents. The results indicated that both neem and mango leaves have an attractive property to remove dye from water. Therefore, both can be used as alternative green adsorbents for pollutant removal. Published on 2022-11-28 00:00:00
  • Lethal yellowing disease in Borassus flabellifer in Jaffna

    • Abstract: Palmyrah palm (Borassus flabellifer Linn.) is a highly versatile tree mainly distributed in the North and Eastern provinces of Sri Lanka. Even though the plant is rarely affected by pathogens due to its extremely woody nature, some significant abnormalities in plants growing in the Pungudutivu area in Jaffna Peninsula have been noted recently. The present study aimed to characterize the abnormality, identify the disease and confirm the possible causative agent. In this study, the progression and incidence of disease were determined through field visits. A literature search was conducted to compare the symptoms with other palm varieties. Additionally, the possibilities for phytoplasma infection were tested with phytoplasma-specific universal primers using PCR. Initially, the plants showed progressive leaf yellowing and drying from the leaf tip towards the petiole followed by collapsed spear leaf hanging downward in the crown. Finally, the crown falls off the trunk. The symptoms are characteristics of the lethal yellowing disease. The PCR result confirmed the association of phytoplasma with the diseased plants. To our knowledge, this is the first report from Sri Lanka regarding the lethal yellowing disease in Palmyrah palm. Since the disease severely affects the plant and spreads rapidly, there is an urgent need to study the epidemiology of the disease and to find out suitable control measures. Published on 2022-11-28 00:00:00
  • Antimicrobial pontential of fungal endophytes obtained from Avicennia
           Marina and Excoecaria Agallocha in Negombo

    • Abstract: Mangroves are halophytic plants that are typically found along the intra-tidal regions. The coastal ecosystem of mangroves in Sri Lanka hold one of the most unique mangrove species that are yet to be studied. These ecosystems provide shelter to various organisms including humans. Fungal endophytes present in these plants have many medicinal properties that can be utilized in the development of drugs. Antibiotic resistance is a major concern in the pharmaceutical industry, hence alternative plant-based drugs with fewer costs and side effects show great potential. In the current investigation, the main objective was to test for antibacterial properties of fungal endophytes isolates from two mangroves: Avicennia marina and Excoecaria agallocha against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922). In both mangrove species, three endophytic species were identified based on their morphological characteristics: Aspergillus niger, Penicillium viticola and Aspergillus versicolor. Only P. viticola was obtained from E. agallocha. Based on the results obtained from antibiotic susceptibility tests, A. niger (stem) was the most active and showed the best bacteriostatic and bactericidal activity against both S. aureus and E. coli. P. viticola produced viable results (mean zone of inhibition of 21 mm against S. aureus) but were not as productive as A. niger. This study indicated that these endophytic fungi held medicinal properties that can be further evaluated. Published on 2022-12-31 00:00:00
  • Development of herbal sunscreen formulations from the leaves of Sri Lankan
           medicinal plants, Hibiscus furcatus wild. and Olax zeylanica Linn

    • Abstract: Excessive exposure to ultraviolet (UV) radiation in the sunlight has many deleterious consequences on human skin. In order to alleviate these harmful effects, sunscreen formulations are widely used. Although most of these synthetic sunscreens are highly effective, the adverse effects associated with these products should not be neglected. The current trend, therefore, is to explore natural sources to develop novel sunscreen formulations that are efficacious and more human-friendly. This study was conducted to formulate herbal sunscreens using two Sri Lankan medicinal plants used as remedies for dermatological conditions, hibiscus furcatus wild (nabiriththa) and olax zeylanica linn. (mella) and to evaluate their efficacy. Initially, aqueous-methanolic extracts were prepared from the leaves of the two plants, followed by the preparation of sunscreen formulations from each extract by incorporating different concentrations of the extracts into an aqueous cream base. Thereafter, the uv absorbance and sun protection factor (spf) were obtained. The sunscreen formulations containing 75% of each extract displayed high UV absorbance and the highest spf values. The photostability profiles indicated that some formulations prepared from o. zeyalnica were more effective than the formulations developed from h. furcatus. Therefore, this preliminary study demonstrated the suitability of h. furcatus and o. zeylanica extracts towards the development of commercial herbal sunscreens. Published on 2022-12-31 00:00:00
  • The minimum normalized cut value of tadpole graphs

    • Abstract: The Tadpole graph Tn,k  is a Lollipop type graph obtained by joining a one vertex of cycle graph Cn  to the end vertex of a path graph Pk  The normalized cut is a measure of disassociation between two groups which computes the cut cost as a fraction of the total edge connections to all the vertices in the graph. This research focuses on deriving a formula to find the minimum normalized cut value of Tadpole graphs. Published on 2022-12-31 00:00:00
  • Proximate and phytochemical analysis of selected wild edible green leafy
           vegetables in Batticaloa

    • Abstract: Plant-derived natural products provide many novel bioactive molecules that are available in the market today as medicines or food. Wild Green Leafy Vegetables (WGLVs) have essential nutrients which are necessary for a healthy life. Three WGLVs such as Allmania nodiflora, Borreria hispida, and Rivea ornata were selected for the proximate and phytochemical analysis based on the market survey. Selected dry WGLVs were used to investigate proximate such as moisture, ash, fat, and fiber and phytochemicals such as alkaloids, flavonoids, tannins, steroids, terpenoids, phenolic compounds, and saponins analysis by using standard methods. The results were shown as follows: moisture 71.7±0.95- 80.3±2.84%, ash 8.84±0.69 - 11.05±0.21 %, fat 1.36±0.48 - 2.56±0.28 % and fiber 6.85±0.46 - 8.04±0.11 %. The qualitative screening of water, ethanol, and acetone extracts revealed that select WGLVs contained alkaloids, flavonoids, tannins, steroids, terpenoids, phenolic compounds, and saponin. Rivea ornata lacked quinones, while anthraquinones were only found in the water extract of Borreria hispida, and none of the three WGLVs were found to contain glycosides. Published on 2022-12-31 00:00:00
  • Development and quality evaluation of oat (Avena sativa)
           incorporated drinking yogurt

    • Abstract: Oat (Avena sativa) is a healthy cereal that is high in fiber and minerals. This research aimed to develop an oat powder incorporated drinking yogurt. 0.25, 0.50, and 1.0 g of oat powder per 100 ml of milk were selected as concentrations. Gelatin was not included due to the stabilizing ability of oat powder. To evaluate consumer preference and proximate analysis, oat concentration selected from a sensory evaluation was compared to a commercial drinking yogurt. For a period of 21 days, physicochemical (pH, Titratable acidity, and Total soluble solids) properties and microbiological quality were examined. The data was statistically analyzed using SSPS and SAS at a significance level of P<0.05. The most consumer-preferred oat concentration was 0.5 g oat powder per 100 ml of milk, with sensory properties identical to commercial drinking yogurt. The fat (3.43), protein (3.30), solids non-fat (26.08), and fiber (0.05) contents of the selected oat concentration were significantly higher than those of the commercial drinking yogurt. According to the yeast and mold count, oat drinking yogurt had a shelf life of 14 days after manufacturing. In conclusion, oat powder including drinking yogurt can be developed with better sensory properties which is competitive with commercial drinking yogurt. Published on 2022-12-31 00:00:00
  • Determination of the antibacterial properties of crude extracts of
           endophytic fungi isolated from Acrostichum aureum and Sonneratia alba

    • Abstract: Current issues associated with drug resistance and the adverse effects of synthetic agents have prompted researchers to focus on natural, medicinal agents such as mangroves and their associated fungal endophytes. The current study was developed to determine the antibacterial activities of crude extracts of endophytic fungi isolated from leaves, roots and stems of Acrostichum aureum, Karan koku in Sinhala and Sonneratia alba, Kirala in Sinhala. The endophytic fungal isolates were identified as Aspergillus niger, Aspergillus ochraceus, Aspergillus fumigatus, Aspergillus terreus, Penicillium citrium and Penicillium resticulosum and the respective crude extracts were generated using ethyl acetate. The crude extracts were subjected to antibiotic sensitivity tests (ABSTs) against two test organisms: Staphylococcus aureus (ATCC ®: 25923) and Escherichia coli (ATCC ®: 25922). The highest inhibitory action was exerted by Penicillium resticulosum against both the test organisms (E. coli: 15+0.05 mm; S. aureus 22+0.05 mm) which was the most abundantly identified endophyte in this study. The Minimum Inhibitory Concentration of the crude extracts was detected to be 1. 25 mg/ ml. However, the highest bactericidal action was noted from Penicillium citrinum. It is evident that the fungal endophytes isolated from mangrove plants possess antibacterial properties that can be used as a natural source for the generation of antimicrobial therapeutics. Published on 2022-12-31 00:00:00
  • Assessment of microbiological and chemical quality of five liter volume
           bottled drinking water

    • Abstract: Consumption of bottled drinking water has dramatically increased among the community in recent years worldwide and also in Sri Lanka. The objective of this study was to assess microbiological and chemical quality of five liter volume bottled water during the shelf life period. Three five liter bottles each of three brands were collected for analysis. Microbiological and chemical analyses were carried out monthly after the date of manufacture throughout the first three months of the shelf life of the bottled water. The results indicated that Total Coliform [TC] and Faecal Coliform [FC] counts decreased with time over the first three months of shelf life. There were no significant differences (P > 0.05) in TC between the numbers of microorganisms initially present, with an average count of 107.19 cfu per 100 ml and those present after three months of storage, which decreased to 33.70 cfu per 100 ml, while the level permitted by SLSI for TC is zero cfu per 100 ml. According to national and international standards, the FC count should be zero per 100 ml for drinking water. However, bottled water samples tested exceeded this limit for presumptive FC, with an average count of 0.63 cfu per 100 ml, which declined to 0.3 cfu per 100 ml after three months, without exhibiting a significant difference (P > 0.05). Chemical parameters were within the permitted levels, except pH and hardness in water samples. Therefore, bottled water available for sale needs to be monitored continuously by relevant authorities, in order to provide safe bottled drinking water to consumers. Published on 2022-12-31 00:00:00
  • Evaluation of cellulolytic fungal-bacterial biofilms for the enhancement
           of bioethanol production

    • Abstract: Biodegradation of lignocellulosic materials by cellulolytic microbial consortia would be beneficial in cellulosic biofuel production. This study aimed at investigating the cellulose degradation potential of fungal-bacterial biofilms (FBBs) followed by bioethanol production. Fungi and bacteria were isolated from soil samples and their cellulolytic activity was analyzed in carboxy methylcellulose medium. FBBs were developed from the selected fungi and bacteria and their cellulolytic activity was evaluated using reducing sugar production through 3,5-Dinitro Salicylic acid method. Cellulolytic digestion followed by fermentation was performed with the selected biofilms by co-culturing Saccharomyces cerevisiae suspension. Ethanol content was quantified by dichromate method and confirmed through FTIR analysis. The highest significant (P < 0.05) cellulolytic activity was observed in Aspergillus niger (F6) and Pseudomonas aeruginosa (B7). Significantly (P < 0.05) the highest cellulolytic activity was recorded by A. niger-P. aeruginosa biofilm (FB2). Fermentation study confirmed higher production of ethanol by the biofilms co-cultured with S. cerevisiae over their single cultures and the highest was recorded by A. niger - Bacillus subtilis biofilm (FB1) co-cultured with S. cerevisiae. In this context, FBB can be considered as an important agent for bioethanol production from cellulosic materials through cellulolytic digestion followed by fermentation. Published on 2022-12-30 00:00:00
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