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Geothermal Gradient and Heat Flow in the Nigeria Sector of the Chad Basin, Nigeria

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Computational Water, Energy, and Environmental Engineering 2016年第2期5卷 70-78页

作者： mohammed yerima kwaya Ewa Kurowska Abdullahi Suleiman Arabi Department of Geology Usmanu Danfodiyo University Sokoto Nigeria Department of Fundamental Geology University of Silesia Katowice Poland Center for Energy Research and Training Ahmadu Bello University Zaria Nigeria

Information on geothermal gradient and heat flow within the subsurface is critical in the quest for geothermal energy exploration. In a bid to ascertain the thermal potential of Nigeria sector of the Chad Basin for energy generation, subsurface temperature information from 19 oil wells, 24 water boreholes drilled to depths beyond 100 metres and atmospheric temperature from the Chad basin were utilized in calculating geothermal gradient of the area. Selected ditch cuttings from the wells were subjected to thermal conductivity test using Thermal Conductivity Scanner (TCS) at the Polish Geological Institute Laboratory in Warsaw. The terrestrial heat flow was calculated according to the Fourier’s law as a simple product of the geothermal gradient and the mean thermal conductivity. Results obtained indicated geothermal gradient range of 2.81 °C/100 m to 5.88 °C/100 m with an average of 3.71 °C/100 m. The thermal conductivity values from the different representative samples range from 0.58 W/m*K to 4.207 W/m*K with an average of 1.626 W/m*K. The work presented a heat flow value ranging from 45 mW/m2 to about 90 mW/m2 in the Nigerian sector of the Chad Basin.

关键词： Geothermal Gradient Heat Flow Chad Basin Thermal Conductivity

Clinical Isolates of Staphylococcus aureus Show Variation in β-Lactamase Production and Are More Susceptible to Antibiotics Conjugated with β-Lactamase Inhibitors

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Open Journal of Medical Microbiology 2016年第4期6卷 143-149页

作者： Uzal Umar Umar Ahmed Faruk Damoroem M. Tanko mohammed B. yerima Department for Biological Sciences Abubakar Tafawa Balewa University Bauchi Nigeria Department of Microbiology Federal University Dutse Dutse Nigeria

β-Lactam antibiotics are a cornerstone in the treatment of bacterial infections on account of its high therapeutic index and selective toxicity—they act by inhibiting the biosynthesis of peptidoglycan, a key component in bacterial cell wall. Ninety (90) clinical specimens obtained from the microbiology unit Specialist Hospital Bauchi were screened for S. aureus, positive isolates were examined for β-Lactamase expression by using two Penicillin G concentrations (5000 IU/ml and 25,000 IU/ml) in acidometric agar technique with phenol red as indicator, and the susceptibility pattern of the isolates to β-Lactam antibiotics was also determined. S. aureus prevalence of 31% (28/90) was obtained, of which 96% (27/28) of strains were β-Lactamase positive in the standard test, while 63% (17/27) were able to hydrolyze penicillin G concentration of 25,000 IU/ml (5X the concentration in the standard test), and a strain was found to be β-Lactamase negative. The resistance to five β-Lactams, ampicillin, cephalexin, amoxicillin, cloxacillin and flucloxaillin, were 100%, 96%, 89%, 74% and 56% respectively. When ampicillin and amoxicillin were conjugated to β-Lactamase inhibitors sulbactam and clavulanic acid respectively the resistance to ampicillin decreased to 21% and to amoxicillin to 15%. The antibiotic susceptibility profile revealed β-Lactamase elaboration to be the major mechanism of resistance to the β-Lactams. β-Lactam utilization as therapeutic option would thus require the search for sensitive irreversible β-Lactamase inhibitors for the β-Lactamase enzymes or agents to block the release of β-Lactamase by strains.

关键词： β-Lactamase Peptidoglycan Transpeptidation Haemolysis Resistance Antibiotics

<i>In-Situ</i>Biostimulatory Effect of Selected Organic Wastes on Bacterial Atrazine Biodegradation

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Advances in Microbiology 2012年第4期2卷 587-592页

作者： Ahmed Faruk Umar Fatimah Tahir Michael Larkin Olubukola Mojisola Oyawoye Balarabe Lawal Musa mohammed Bello yerima Ediga Bede Agbo Biological Sciences Programme Abubakar Tafawa Balewa University Bauchi Nigeria Microbiology Department Usmanu Dan Fodio University Sokoto Nigeria Queens University Environmental and Genomic Research (QUESTOR) Center Queens University of Belfast Belfast Northern Ireland UK

The biostimulatory effect of selected organic wastes on bacterial biodegradation of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) in three agricultural soils in Bauchi state, Nigeria, was carried out. The soil physico-chemical characteristics were investigated to further understand the environmental conditions of the sampling sites. Enrichment technique was used to isolate the atrazine-degrading strains. Mineralization studies were carried out to determine atrazine biodegradation potentials of strains. Polymerase Chain Reaction (PCR) amplification of total nucleic acid of strains revealed several bacterial species based on nucleotide sequence analyses. Biostimulatory effect of selected organic wastes carried out showed minimal to average extent of biodegradation. The highest mean values, in CFU/mL, increase in biomass was recorded in Pseudomonas sp for both Cow dung 16.76 (42.03%) and Chicken droppings 12.32 (38.46%). However, biostimulatory effect using consortia provided more promising results, with 41.51% and 42.08% in Cow dung and Chicken droppings, biomass increase, respectively, in studies conducted. This proves that competition, survival of inoculums, bioavailability of organic amendments and nature of chemical are important factors affecting bioremediation.

关键词： Biostimulation Biodegradation Bioremediation Mineralization Atrazine

AtzABC Catabolic Gene Probe from Novel Atrazine-Degrading Rhodococcus Strain Isolated from a Nigerian Agricultural Soil

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Advances in Microbiology 2012年第4期2卷 593-597页

作者： Ahmed Faruk Umar Fatimah Tahir Michael J. Larkin Olubukola Mojisola Oyawoye Balarabe Lawal Musa mohammed Bello yerima Ediga Bede Agbo Biological Sciences Programme Abubakar Tafawa Balewa University Bauchi Nigeria Microbiology Department Usmanu Dan Fodio University Sokoto Nigeria Queens University Environmental and Genomic Research (QUESTOR) Center Queens University of Belfast Belfast Northern Ireland UK

A batch enrichment technique was used to isolate atrazine-degrading Rhodococcus sp strain from an agricultural land with history of atrazine application in Bauchi state, Northeastern Nigeria. The strain was identified on the basis of physiological, biochemical and 16S r RNA gene sequencing. Growth studies and HPLC analysis showed that the strain has potential of atrazine degradation. An investigation into the catabolic genes Atz ABC, which transform atrazine to cyanuric acid, confirms the chromosomal DNA of strain to harbor BC genes, as compared with the positive control, Rhodococcus jostii RHA1. The strain does not possess the Atz A in all catabolic gene probe carried out. The isolation and characterization of the Rhodococcus sp strain showed that catabolic genes may have evolved from a single origin with widespread global distribution, with possible potential in atrazine bioremediation.

关键词： Enrichment Catabolic Genes Bioremediation Atrazine