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Item Nutritional and anti-nutritional composition of Diospyros mespiliformis and Hyphaene petersiana fruits from Namibia(University of Namibia, 2019) Nyambe, Moola M.; Hakwenye, Hilaria; Benyamen, M.S.Wild fruits play an important role in the well-being of many people in Namibia. Two wild fruits namely, Diospyros mespiliformis Hochst. ex A. DC (Ebenaceae) and Hyphaene petersiana Klotzsch ex Mart. (Arecaceae) were analyzed for proximate, nutritional and anti-nutritional composition. The proximate results showed that the moisture content ranged between 8.3-12%, crude fat (0.1-0.45 mg/g), crude protein (1.6-2.6 mg/g), carbohydrate (4-5.3 mg/g), and ash content (3.3-6 mg/g). The mineral contents of the studied fruits were: calcium (5.01-20.33 mg/kg), potassium (94.8-245.94 mg/kg) and sodium (2.80-11.65 mg/kg). Trace elements such as iron (0.14-2.44 mg/kg) and zinc (0.17-0.19 mg/kg) were also detected. Anti-nutrient values were lower than those for established toxic values. High levels of saponins (2.46 mg/g), tannins (0.10 mg/g) and phytate (0.12 mg/g) were detected in H. petersiana pulp, and oxalate (0.04 mg/g) was detected in D. mespiliformis pulp. However, these anti-nutritional factors were within established safe consumption limits. The results of this study signify that the two fruits have high concentrations of essential minerals and low anti-nutrients; thus their consumption is recommended, especially in poor settings.Item Measurement of natural radioactivity and dose rate assessment of terrestrial gamma radiation in the soils of Karibib and Okahandja, Namibia(University of Namibia, 2019) Midzi, Wilfred; Oyedele, James; Shimboyo, Simon A.; Taapopi, Erastus E.The activity concentrations of the naturally occurring radionuclides 238U, 232Th and 40K in soil samples taken from the towns of Okahandja and Karibib in Namibia have been determined by gamma-ray spectroscopy using an HPGe detector. The average activity concentrations of 238U, 232Th and 40K in Karibib are 29.4±5.8Bq/kg, 49.0±8.6Bq/kg, and 824.3±153.5Bq/kg while they are 40.9±8.6Bq/kg, 57.9±19.4Bq/kg, and 562.4±125.4Bq/kg respectively in Okahandja. Most of these values are much higher than the corresponding worldwide average values. These activity concentrations were used to calculate different radiological parameters in order to evaluate the associated health hazard. The value of 9.5×10−2 mSv/y obtained for the mean effective dose rate in both towns is far below the permissible limit of 1.0mSv/y recommended by the ICRP and implies that there is no significant radiation hazard in the towns. Also, the values of 163.0Bq/kg and 167.1Bq/kg obtained for the average radium equivalent activity (Raeq) in the towns and the corresponding values obtained for the average external hazard index (Hex) are much below their maximum permissible limits thus confirming that radiological hazard is negligible in the towns.Item A study on cost analysis and implementation of solar power systems for rural development in Namibia: Case study - Onaushe village, Oshana Region in northern Namibia(University of Namibia, 2019) Katanga, Lusia; Shilongo, Elise; Shafudah, Natangue H.; Singh, ShyamIn most developing countries, especially in rural and remote communities, lack of access to light energy is an obstacle to development. This paper presents a cost analysis study for the implementation of solar power systems in rural Namibia. The study mainly focuses on the contemporary cost for different lighting sources currently employed and compares it with the possible cost of a basic solar system being utilized. The data collected was obtained through a field survey with structured interview questions in Onaushe village, Oshana Region, northern Namibia. The results revealed that 87% of the sampled homesteads had no access to electricity and relied on traditional energy sources such as torches, candles, cellphones and firewood to meet their lighting needs. The study further found that solar power system has high initial cost compared to the lighting sources being used in rural areas. Recommendation for some relevant strategies that may enable the implementation of solar power systems are discussed.Item Molecular differentiation of rifampicin and isoniazid drug resistant Mycobacterium tuberculosis complex isolated from selected parts of Zambia(University of Namibia, 2019) Kapona, O.; Kaimoyo, E.; Katongo, C.The most prevalent Mycobacterium species in the Mycobacterium tuberculosis complex and frequency of mutations in the genes conferring resistance to rifampicin and isoniazid in Zambia have until now remained unknown. This study sought to differentiate the isolates of Mycobacterium tuberculosis complex (MTBC) using genetic regions cfp32, RD9 and RD12 and determine the prevalence of resistance-associated mutations in two specific resistance marker genes (rpoB and katG) and the inhA promoter region of M. tuberculosis isolated at the University Teaching Hospital Tuberculosis Laboratory between January 2013 and June 2014. Genomic DNA was extracted from 40 isolates and amplified by multiplex PCR for regions cfp32, RD9 and RD12 and single PCRs for three drugresistance conferring loci (katG, rpoB and inhA). All isolates were positive for the three regions typical of M. tuberculosis. Seventy-five percent had the S315T mutation in katG gene and one had mutations in the inhA promoter and rpoB in addition to the katG 315 mutation. The S450L (48.7%) and H445Y (20.5%) mutations were the most frequently observed mutations in the rpoB gene while rifampicin mono-resistance was observed in 2.6% of the rifampicin-resistant isolates. Molecular diagnostic tests based on detecting these predominant mutations could be useful for the rapid detection of multi drug resistant tuberculosis in Eastern, Lusaka, Western parts of Zambia and TB patients in these regions can be treated with the standard first line tuberculosis drugs.Item Molecular characterization of culturable thermophilic prokaryotes from Chinyunyu hot spring in central Zambia(University of Namibia, 2019) Kalumbilo, M.P.; Kaimoyo, E.; Phiri, J.Hot springs are among some of the naturally-occurring extreme environments that have generated considerable interest in researchers worldwide. Thermophilic prokaryotes present in hot spring habitats are considered valuable sources for biotechnological products including thermally-stable enzymes applied in many research and manufacturing process. Despite the numerous hot springs in Zambia, there is limited information on the diversity of thermophilic prokaryotes in these places. In this study, characterization of thermophilic prokaryotes isolated from Chinyunyu hot spring in Lusaka province, Zambia was conducted using phenotypic and molecular-methods. The recorded temperature of the hot spring at the time of sampling was 60 C and the pH was 9.0 indicating alkaline environment. A total of 13 phenotypically distinct isolates were identified on nutrient agar medium at 55 C and pH 7.0. All isolates were Gram-positive, rod-shaped cells. Their genomic DNA was PCR-amplified using 16S rRNA primers and sequenced using the Big Dye Terminator v3.1 cycle sequencing kit on the ABI Prism 3130xl Genetic Analyzer (Life Technologies Corp). Amplicon sequences were analyzed using Basic Local Alignment Search Tool (BLAST) and revealed that all isolates belonged to the bacterial phylum Firmicutes. Seven isolates were affiliated to the genus Anoxybacillus and six were affiliated to the genus Bacillus. The study revealed that Chinyunyu hot spring harbours genetically diverse thermophilic prokaryotes which could be amenable to further studies to exploit the hot spring microbiome for its biotechnological potential.Item Influence of transition metal doping on the structural and optical properties of iron chromium nano oxides(University of Namibia, 2019) Kalengay, M.; Nsio, Tony N.; Osman, N.S.We have synthesized Sn0.2Fex Cr1.8 – xO3 nano oxides with x= 0.0, 0.1, 0.2, 0.3. Single phase corundum structure and nanophase structure of the as-synthesized samples were confirmed by X-ray diffraction (XRD) and by transmission electron microscope (TEM). Crystallite sizes were calculated using the Scherrer’s formula whilst particle sizes were obtained by TEM and found to be varying from 27.06 to 32.05 nm for the samples synthesized at different iron content. The optical measurements were performed by UV-visible spectroscopy. We observed that the band gaps and the refractive index vary with iron content.Item Structural and optical studies of tin iron chromium nano oxides(University of Namibia, 2019) Kalengay, M.; Nsio, Tony N.In the present study, we have synthesized Sn0.2Fe0.9Cr0.9O3 nano oxides. Single phase corundumlike structure and nanophase structure of the as-synthesized sample were confirmed by x-ray diffraction (XRD) and by transmission electron microscope (TEM). The results show that the produced powders have grain size of approximately 32 nm. Using the result of the ultraviolet-visible (UVVis) spectrometer, we were able to determine the energy band gaps of 3.1 and 5.2 eV , when nanoparticles are diluted in iron standard solution and in deionised water respectively.Item Assessment of natural radioactivity levels and radiation hazards in shore sediments from the Zambezi River, Namibia(University of Namibia, 2019) Amwaalanga, Maria N.; Onjefu, Sylvanus A.; Zivuku, Munyaradzi; Hamunyela, Roswita H.In this study, the radioactivity concentrations and the potential health hazards of primordial radionuclides; 238U, 232Th and 40K were measured using a gamma ray spectrometer in 30 soil samples collected from the Zambezi River, Namibia. The average activity concentrations for 238U, 232Th and 40K was found to be 18.91 Bq/kg, 15.58 Bq/kg and 79.17 Bq/kg respectively. The activity concentrations of the measured radionuclides were used to calculate the radiological hazards in soil samples i.e. absorbed dose rate, annual effective dose equivalent, radium equivalent activity and hazard indices (Hex and Hin). From the values obtained, all the radiological hazard parameters were within the world acceptable average values. However, the mean annual effective outdoor and indoor dose equivalent was found to be 0.26 mSv/y and 1.05 mSv/y, respectively, which both exceed the recommended world average United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) values of 0.07 mSv/y for outdoor and 0.45 mSv/y for indoor.