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Characterization of Coal Spoil Recovered from Coal Mine Drainage Water

Journal of Geoscience and Environment Protection 2017年第11期5卷 227-236页

作者： aninda nafis ahmed Md. Anwar Arfien Khan Madhu Sudan Saha Sharmin Sultana Pilot Plant and Process Development Centre (PP & PDC) BCSIR Dhaka Bangladesh Leather Research Institute (LRI) BCSIR Savar Dhaka Bangladesh Institute of Mining Mineralogy and Metallurgy (IMMM) BCSIR Joypurhat Bangladesh

Barapukuria Coal Mine situated in the district Dinajpur. Bangladesh is playing an important role in the economy of this country by the mining of top quality coal. With coal mining, mine waste is also generated called coal spoil. Coal spoil can impose environmental threat if not treated carefully. In contrast, it can also be converted to value added product. In the present work, coal spoils collected from Barapukuria coal mine drainage water were investigated to determine the quality of the samples by physico-chemical analysis (proximate and ultimate analysis) as well as by heating value determination. 50% of carbon was detected in the samples after elemental analysis, with sulfur content less than 0.4%. Calorific value around 9300 btu/lb was obtained for the coal spoil. Moreover, moisture content, ash, volatile matter content and fixed carbon also provided fruitful information regarding the quality and economic prospect of the samples in comparison to the quality of Barapukuria coal.

关键词： Coal Spoil Calorific Value XRF XRD Particle Size Analysis Thermal Analysis

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Structural and Dielectric Properties of (Bi₂O₃Fe₂O₃)_0.4(Nb₂O₅)_0.6 for Different Sintering Temperature

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Materials Sciences and Applications 2016年第8期7卷 421-429页

作者： Sadia Tasnim Mowri M. A. Gafur Quazi Delwar Hossain aninda nafis ahmed Muhammad Shahriar Bashar Electrical and Electronic Engineering Department Chittagong University of Engineering and Technology Chittagong Bangladesh Pilot Plant & Process Development Centre Bangladesh Council of Scientific and Industrial Research Dhaka Bangladesh Institute of Fuel Research & Development Bangladesh Council of Scientific and Industrial Research Dhaka Bangladesh

In this research work, (Bi2O3Fe2O3)0.4(Nb2O5)0.6 was made by the solid state reaction method. Samples were sintered at four different temperatures (850°C, 925°C, 1000°C and 1150°C) to study the effect of sintering temperature on the various properties of the samples. X-ray diffraction analysis confirmed that single phase Bi1.721δ0.089Fe1.056Nb1.134O7 was found when sintering temperature increased. At the same time, larger grain size was found when sintering temperature increased. From variation of dielectric loss with respect to frequency, a small peak was found when sample was sintered at higher temperature (1150°C). Dielectric constant of the sample decreases with the increase of frequency for all the samples. With the variation of temperature, DC resistivity of the samples showed that resistivity decreases with the increase of measuring temperature which indicates semiconducting nature.

关键词： XRD Niobium SEM Dielectric Constant Dielectric Loss Loss Tangent Bismuth Ferrite Resistivity

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Endophytic actinobacteria of medicinal plant Aloe vera: Isolation, antimicrobial, antioxidant, cytotoxicity assays and taxonomic study

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Asian Pacific Journal of Tropical Biomedicine 2018年第10期8卷 513-518页

作者： ahmed nafis Ayoub Kasrati Asma Azmani Yedir Ouhdouch Lahcen Hassani Laboratory of Biology and Biotechnology of Microorganisms Faculty of Sciences SemlaliaCadi Ayyad University Department of Biology Faculty of Sciences SemlaliaCadi Ayyad University

Objective: To explore the new sources of novel bioactive compounds having pharmaceutical and agricultural interest and to search the endophytic actinobacteria from medicinal plants. Methods: NAF-1 an endophyte actinobacteria was isolated from leaves of medicinal plant Aloe vera collected in Marrakesh, Morocco using Bennett agar as selective medium. NAF-1 was tested for its antimicrobial activity against five pathogenic bacteria such as Staphylococcus aureus PIC 53156, Micrococcus luteus ATCC381, Bacillus subtilis ATCC 14579, Pseudomonas aeruginosa DSM 50090 and Escherichia coli ATCC 8739 and four human clinic fungi belonging to the Candida, Aspergillus and Microsporum genera. Several antioxidant activities were studied such as DPPH free radical scavenging, β-carotene and linoleic acid and reducing power assays. The total of phenol and flavonoid was also calculated. Using Artemia salina shrimp assay, the cytotoxicity of NAF-1 crude extract was determined. Results: The results revealed that the actinobacteria showed a high activity(≥20 mm) against only Gram positive bacteria but it had a moderate activity(between 13 and 15 mm) against Human clinic fungi. The isolate also exhibited a LD50 of 14.20 μg/mL in the cytotoxicity assay. The result showed that the crude extract presented an interesting free radical-scavenging activity with IC50 value of(5.58 ± 0.26) μg/mL and a high value of phenolic and flavonoid compounds with(15.41 ± 0.18) μg GAE/mg extract and(11.41± 0.06) μg QE/mg extract respectively. Moreover, the taxonomic position of our endophyte actinobacteria using the morphological and physiological criteria and using 16 S r RNA gene sequence(polyphasic approach) showed that the NAF-1 isolate was similar to Streptomyces hydrogenans which was never described as an endophyte actinobacteria. Conclusions: This isolated strain appears promising resources of bioactive agents and can be exploited to produce therapeutic agents active against pathogenic disease.

关键词： Actinobacteria Medicinal plant Aloe vera Antimicrobial activity Cytotoxicity Antioxidant assays Molecular identification

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In vitro antimicrobial and synergistic effect of essential oil from the red macroalgae Centroceras clavulatum (C. Agardh) Montagne with conventional antibiotics

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Asian Pacific Journal of Tropical Biomedicine 2021年第9期11卷 414-420页

作者： ahmed nafis Fatima El Khalloufi Asmae Aknaf Brahim Oudra Najat Marraiki Sarah Al-Rashed Abdallah MElgorban Asad Syed Lahcen Hassani Luísa Custódio Microbiology Health and Environment TeamFaculty of Sciences Chouaïb Doukkali UniversityEl JadidaMorocco Laboratory of Chemistry Modeling and Environmental SciencesPolydisciplinary Faculty of KhouribgaSultan Moulay Slimane University of Beni MellalB.P.:14525000KhouribgaMorocco Polydisciplinary Faculty of Nador University Mohammed FirstBP 30062700NadorMorocco Laboratory of Water Biodiversity and Climate Change.Faculty of Sciences Semlalia MarrakechCadi Ayyad UniversityP.O.Box 239040000MarrakechMorocco Department of Botany and Microbiology College of ScienceKing Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia Laboratory of Microbial Biotechnologies Agrosciencesand Environment(BioMAgE)Faculty of Sciences Semlalia MarrakechCadi Ayyad UniversityP.O.Box 239040000MarrakechMorocco Center of Marine Sciences Faculty of Sciences and TechnologyUniversity of AlgarveEd.7Campus of Gambelas8005-139 FaroPortugal

Objective:To study the chemical profile,antimicrobial properties,and synergistic effect with known antibiotics of essential oil extracted from the marine red macroalgae Centroceras clavulatum(***)Montagne,collected in ***:The chemical composition of the oil was analyzed by gas chromatography-mass *** oil was evaluated for antibacterial(Pseudomonas aeruginosa,Escherichia coli,Bacillus subtilis,Micrococcus luteus,Staphylococcus aureus,and Klebsiella pneumoniae),and antifungal activity(Candida albicans,Candida glabrata,Candida krusei,and Candida parapsilosis),by the disc diffusion *** minimum inhibitory and minimum microbicidal concentrations of the oil were determined,as well as the synergistic effects of its application combined with the antibiotics ciprofloxacin and fluconazole,by the checkerboard ***:Thirty molecules were identified in the essential oil,comprising 96.27%of the total oil *** such as carvacrol(36.06%)were the most abundant compounds,followed by caryophyllene(14.67%),endo-borneol(9.04%),pyroterebic acid(3.23%)and caryophyllene oxide(3.13%).The oil exhibited a moderate antimicrobial activity with inhibition zone diameters ranging from 9.0 to 15.0 *** minimum inhibitory concentration values varied between 0.9 and 14.7 mg/mL,and Bacillus subtilis and Escherichia coli were the more sensitive bacteria with 0.9 and 1.9 mg/mL,*** minimum microbicidal concentration values ranged from 0.4 to 14.7 mg/mL.A significant synergic action was observed when the oil was applied in combination with ciprofloxacin and fluconazole,with fractional inhibitory concentration index values ranging from 0.31 to *** was found in 80%of the combinations and a 2 to 16-fold reduction of antibiotics MIC was ***:Our findings suggest that the essential oil of Centroceras clavulatum should be further appraised for its potential use in the management of multi-drug resistant microo

关键词： Macroalgae Centroceras clavulatum(C.Agardh) Antimicrobial potential Microbial drug resistance Marine natural products Synergism with antibiotics

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