Tanzania Journal of Science https://www.ajol.info/index.php/tjs <p><strong><em>Tanzania Journal of Science</em></strong> (<em>Tanz. J. Sci.</em>)&nbsp; is an <strong>international journal</strong> published by the College of Natural and Applied Sciences, University of Dar es Salaam. The <strong><em>Tanzania Journal of Science</em></strong>,&nbsp;formerly known as “<em>University Science Journal", </em>was established in 1975 as a forum for communication and co-ordination between and among scientists and allied professionals. It is also intended as a medium for dissemination of scientific knowledge among scientists and the public at large to promote the advancement of pure and applied sciences. Tanzania Journal of Science publishes high quality contributions on original works in the fields of pure and applied sciences. Its review processes and decision criteria are rigorous. The manuscripts are evaluated by expert reviewers and editors to assess their scientific quality. Those manuscripts judged by the editors and Chief Editor to be of insufficient scientific quality or interest, or generally inappropriate are rejected promptly without formal review. Also, manuscripts not complying with the journal requirements and author guidelines are returned to the authors or rejected. The decisions regarding acceptance or rejection of papers are independent, unbiased and fair.&nbsp;</p> <p>Indexed/Abstracted in: African Journals OnLine (AJOL); CAB International or CABI (Centre for Agriculture and Bioscience International, UK); CAB Direct; CAB Abstracts; CAB Global Health; Google Scholar; Journals for Free (J4F) database</p> <p><strong>For online submission please <a href="https://tjs.udsm.ac.tz/index.php/tjs/onlinesubmission" target="_blank" rel="noopener">click here</a></strong></p> College of Natural and Applied Sciences (CoNAS) of the University of Dar es Salaam (UDSM) en-US Tanzania Journal of Science 0856-1761 <p>Copyright for articles published in this journal is retained by the journal.</p><p>This journal provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge</p> Biological Characterization of Plasmodium falciparum Mitochondrial Heat Shock Protein PfHsp70-3: Possible Involvement in Malaria Pathogenesis https://www.ajol.info/index.php/tjs/article/view/216471 <p>Malaria remains a global health burden accounting for many deaths and illnesses in sub-Saharan Africa notwithstanding many decades of research on the disease. <em>P. falciparum</em>, the causative agent of the most fatal form of malaria, expresses a repertoire of heat shock proteins (Hsp) that cushion the parasite against heat shocks as it shuttles between extreme temperatures in human and mosquito vector hosts. By so doing, such proteins promote parasite’s cytoprotection, survival and pathogenesis. Heat shock proteins are named according to their molecular weights and there are six <em>P. falciparum</em> Hsp70 (PfHsp70) found in various cell compartments with mitochondrial putative PfHsp70-3. Using indirect immunofluorescence, this study established mitochondrial localization of PfHsp70-3 though some more confirmatory studies would be needed in the future. PfHsp70-3 was found to be heat inducible and expressed during all stages of the intra-erythrocytic cycle of parasite development. This could be an indication of PfHsp70-3’s involvement in the infectivity process of <em>P. falciparum</em> by helping the parasite to resist heat shocks during malaria febrile episodes. Generally, the data obtained in this study will enhance the existing knowledge on the biology of <em>P. falciparum</em> mitochondrial heat shock protein functions and open possible avenues for targeting the specificity between PfHsp70-3 and its co-chaperones for drug development.</p> <p><strong>Keywords</strong>: Malaria, <em>P. falciparum</em>, Heat shock proteins, PfHsp70-3, pathogenesis</p> David O. Nyakundi Aileen Boshoff Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1338 1351 10.4314/tjs.v47i4.1 Automated Detection of Bilingual Obfuscated Abusive Words on Social Media Forums: A Case of Swahili and English Texts https://www.ajol.info/index.php/tjs/article/view/216472 <p>The usage of social media has exponentially grown in recent years leaving the users with no limitations on misusing the platforms through abusive contents as deemed fit to them. This exacerbates abusive words exposure to innocent users, especially in social media forums, including children. In an attempt to alleviate the problem of abusive words proliferation on social media, researchers have proposed different methods to help deal with variants of the abusive words; however, obfuscated abusive words detection still poses challenges. A method that utilizes a combination of rule based approach and character percentage matching techniques is proposed to improve the detection rate for obfuscated abusive words. The evaluation results achieved F1 score percentage ratio of 0.97 and accuracy percentage ratio of 0.96 which were above the significance ratio of 0.5. Hence, the proposed approach is highly effective for obfuscated abusive words detection and prevention.</p> <p><strong>Keywords:</strong>&nbsp;&nbsp;&nbsp;&nbsp; Rule based approach, Character percentage matching techniques, Obfuscated abuse, Abuse detection, Abusive words, Social media</p> Geofrey Njovangwa Godfrey Justo Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1352 1361 10.4314/tjs.v47i4.2 Pair Distribution Function Analysis and Electrochemical Performance of Mesoporous Carbon Nanomaterials Synthesized Through KOH and ZnCl2 Activation https://www.ajol.info/index.php/tjs/article/view/216473 <p>Mesoporous carbon has been synthesized by activating carbonized biogas slurry residues with ZnCl<sub>2</sub> and KOH simultaneously. The carbon to activating agent mass ratios were kept at 1:4, while the ZnCl<sub>2</sub> to KOH mass ratio varied from 4:0, 3:1, 2:2, 1:3, to 0:4. The highest BET specific surface area of 361 m<sup>2</sup> g<sup>-1</sup>, micropore surface area of 231 m<sup>2</sup> g<sup>‒1</sup>, mesopore surface area of 125 m<sup>2</sup> g<sup>‒1</sup>, and total pore volume of 0.23 cm<sup>3</sup> g<sup>‒1</sup> which amounted to 78% mesopore content, were obtained for the sample with 3:1 ZnCl<sub>2</sub> to KOH mass ratio. Scanning electron microscope (SEM) images were acquired to determine the surface morphology and energy dispersive X-ray (EDX) was used to determine surface composition of the samples. The short, medium, and long-range orders of the synthesized materials were studied using pair distribution function (PDF) analysis. PDF showed that in addition to the locally ordered carbon and silica phase components, samples activated using combined ZnCl<sub>2</sub> and KOH also contained crystalline Zn<sub>2</sub>SiO<sub>4</sub> phase with the willemite structure. Electrochemical studies in three-electrode cell system revealed maximum specific capacitance of 216 F g<sup>‒1</sup> exhibited by sample with a ZnCl<sub>2</sub>: KOH mass ratio of 3:1 at a scan rate of 5 mV s<sup>‒1</sup>.</p> <p><strong>Keywords: </strong>Mesoporous carbon; Pair distribution function, Specific capacitance, supercapacitor</p> <p>&nbsp;</p> Talam E. Kibona Sarah Frisco Maxwell W. Terban Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1362 1375 10.4314/tjs.v47i4.3 Effects of Refuge Prey on Stability of the Prey-Predator Model Subject to Immigrants: A Mathematical Modelling Approach https://www.ajol.info/index.php/tjs/article/view/216475 <p>Prey-predator system is enormously complex and nonlinear interaction between species. Such complexity regularly requires development of new approaches which involves more factors in analysis of its population dynamics. In this paper, we formulate a modified Lotka-Volterra model that incorporates factors such as refuge prey and immigrants. We investigate the effects of refuge prey and immigrants by varying the refuge factor, with and without immigrants. The results show that with Holling’s type I functional response, the proposed model is asymptotically convergent when a refuge prey factor is introduced. Moreover, with Holling’s type II functional response, the proposed mathematical model is unstable and does not converge. However, with Holling’s type III functional response in a system, the proposed mathematical model is asymptotically stable. These results point out the following remarks: The effects of refuge prey on stability of the dynamical system vary depending on the type of functional response, and when the predator population increases, the likelihood of prey extinction declines when the proportion of preys in refuge population increases. Hence, the factor of refuge prey is crucial for controlling the population of the predator and obtaining balances between prey and predator in the ecosystem.</p> <p><strong>Keywords:</strong> Refuge prey, stability, prey-predator, immigrants, Mathematical modelling</p> Mussa Amos Stephano Il Hyo Jung Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1376 1391 10.4314/tjs.v47i4.4 Inversion free Iterative Method for Finding Symmetric Solution of the Nonlinear Matrix Equation 𝑿 − 𝑨∗𝑿𝒒𝑨 = 𝑰 (𝒒 ≥ 𝟐) https://www.ajol.info/index.php/tjs/article/view/216492 <p>In this paper, we propose the inversion free iterative method to find symmetric solution of the<br>nonlinear matrix equation 𝑿 − 𝑨∗𝑿𝒒𝑨 = 𝑰 (𝒒 ≥ 𝟐), where 𝑋 is an unknown symmetric<br>solution, 𝐴 is a given Hermitian matrix and 𝑞 is a positive integer. The convergence of the<br>proposed method is derived. Numerical examples demonstrate that the proposed iterative method<br>is quite efficient and converges well when the initial guess is sufficiently close to the approximate<br>solution.</p> <p><strong>Keywords</strong>: Symmetric solution, nonlinear matrix equation, inversion free, iterative method</p> Chacha Stephen Chacha Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1392 1401 10.4314/tjs.v47i4.5 Analysing Climate Change Mitigation Policy Options in the Renewable Energy Sub-Sector in Tanzania https://www.ajol.info/index.php/tjs/article/view/216488 <p>Public policies influence reduction of greenhouse gas emissions. Also the extent to which policies are developed and implemented can influence the achievement of the national, regional and international climate change mitigation policy framework in the renewable energy sub-sector. This paper provides a critical overview of key policy options influencing the development of renewable energy sub-sector through climate change mitigation policy options in Tanzania. Questionnaire surveys were used to collect primary data from 100 relevant experts who represented 64 organizations in Tanzania. Secondary data were collected by literature review. The state of climate change mitigation policy options in the renewable energy sub-sector was assessed by using Statistical Product and Service Solutions (SPSS) version 26.0 and content analysis. The results showed Tanzania lacks adequate climate change mitigation policy and renewable energy policy frameworks. A specific national climate change policy and national renewable energy policy are needed to guide stakeholders to undertake climate change mitigation actions in the renewable energy sub-sector in Tanzania. Perceptions gained and recommendations made are essential for undertaking climate change mitigation actions in Tanzania, and can be relevant for other developing countries because of similar climate change mitigation contexts.</p> <p><strong>Keywords:</strong> climate change, renewable energy, greenhouse gases, policies, Tanzania</p> Ladislaus Kyaruzi Patrick M Ndaki Richard YM Kangalawe Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1402 1411 10.4314/tjs.v47i4.6 Harnessing Nutritional Benefits of Spirulina platensis: Standardization of Cultivating Conditions of Spirulina in Kilimanjaro https://www.ajol.info/index.php/tjs/article/view/216476 <p>Malnutrition remains a challenge in Tanzania, notwithstanding government initiatives and health education geared towards assuaging the problem. According to the World Health Organization (WHO), there will be more than 600,000 severely malnourished children in Tanzania by the year 2030. In particular, protein based malnutrition remains the greatest challenge due to the irreplaceable nature of its essential amino acids. Macronutrients and micronutrients which are found in <em>Spirulina platensis </em>have been recommended by WHO to address malnutrition in developing countries. <em>Spirulina platensis</em> is a filamentous Cyanobacterium microalgae with the highest recorded protein content of plant origin with several immune boosting nutrients. Spirulina cultivation requires sufficient aeration, proper light intensity and salinity for maximum biomass yield, cell productivity, specific growth rate, and protein content. This paper presents the findings of a study carried out in Kilimanjaro on the optimized conditions, locally and economically tailored approach system required to grow spirulina in the region. The study established the use of food grade organic media with low-cost urea as nitrogen source, a greenhouse average temperature of 30–32 °C in the months between December to March, alkalinity of 5 g/L, mixing frequency of 3 times per day/100 L&nbsp; and partial shading, as the optimum conditions for outdoor cultivation of spirulina.</p> <p><strong>Keywords</strong>: Malnutrition, Spirulina, Protein, growth condition</p> David O. Nyakundi Phocus Cleophas Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1412 1423 10.4314/tjs.v47i4.7 Vulnerability and Responses of Smallholder Farmers to Climate Change Effects in Semiarid Areas of Bahi and Kongwa Districts, Tanzania https://www.ajol.info/index.php/tjs/article/view/216479 <p>This study examined the vulnerability and responses of smallholder farmers to climate change effects in Semiarid Areas of Bahi and Kongwa Districts. A total of 366 household heads were involved in this study. The study employed questionnaire, interviews and documentary review as data collection techniques. Archival data for temperature, rainfall and crop yields were collected for trend analysis. Descriptive and inferential statistics were used to analyse quantitative data, content analysis was employed to analyse qualitative data. Simple linear trend analysis and Mann Kendall were used to establish trends. The findings indicate that smallholder farmers in the study area have noted reduced rainfall, increased temperature and reduced production as indicators of climate change. Results from archival data indicate insignificant decline of rainfall, significant increase of temperature and insignificant decline of crop yields at 5% significance level. As a response to these changes, smallholder farmers reported to use improved crop varieties, change planting dates, use intercropping, out-migrating and change land use practices. Several challenges were reported to hinder effective adaptation including inadequate capital, limited soft loans, limited weather information and deficient extension services. &nbsp;It is concluded that the climate is changing in the study area calling for strengthening farmers’ adaptive capacity.</p> <p><strong>Keywords: </strong>Adaptive strategies, climate change effects, challenges, semiarid area, Tanzania.</p> Helena Elias Myeya Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1424 1435 10.4314/tjs.v47i4.8 Comparison of Nutritional and Anti-Nutritional Qualities of Grewia forbesii Hav. Ex Mast and Grewia bicolor Juss Fruits from Kitapilimwa Forest Reserve in Iringa District https://www.ajol.info/index.php/tjs/article/view/216495 <p>The <em>Grewia forbesii</em> and <em>Grewia bicolor</em> fruits were collected from Kitapilimwa Forest Reserve and were analysed for proximate, nutrients and anti-nutrients compositions. Results showed low moisture contents in <em>G. forbesii</em> and <em>G. bicolor </em>amounting to 14.14 and 13.98 percent, respectively. Crude fibre percent was slightly higher in <em>G. bicolor </em>(33.15%) than <em>G. forbesii</em> (31.95%). Lipid content was slightly higher in <em>G. bicolor </em>(1.37%) compared to <em>G. forbesii </em>(1.28%). The crude protein content of <em>G. forbesii</em> (7.44%) was slightly higher than <em>G. bicolor </em>(7.00%). Total carbohydrate content of <em>G. forbesii</em> (68.9%) was higher than that of G<em>. bicolor</em> (70%). Mineral analysis indicated substantial amounts of potassium 898 mg/100 g in <em>G. forbesii</em> and 879 mg/100 g in <em>G</em>. <em>bicolor</em>. Calcium content was high in <em>G. forbesii</em> and <em>G. bicolor</em> amounting to 453 mg/100 g and 582 mg/100 g, respectively. Iron was high in both species (20.73–24.45 mg/100 g). Manganese, copper and zinc were substantially low. The results revealed low levels of tannin (&lt; 1.7%) and phylates (&lt; 0.3%). The presence of substantial amounts of nutrients and low anti-nutrients revealed that the studied species may be potential sources of nutritional food.</p> <p><strong>Keywords: </strong>Proximate analysis, mineral nutrients, anti-nutritional qualities, <em>Grewia</em> species, Kitapilimwa Forest Reserve</p> Vendeline E. Tairo Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1436 1441 10.4314/tjs.v47i4.9 Assessment of African Blackwood (Dalbergia melanoxylon) Population Structure in Kilwa District, Tanzania https://www.ajol.info/index.php/tjs/article/view/216480 <p>Overharvesting and limited conservation efforts have posed a serious threat to future availability of <em>Dalbergia melanoxylon </em>in Tanzania in recent years. The study was conducted between 2018 and 2020 covering Mitarure Forest Reserve (MFR) and 2 surrounding community forests of Ngea and Nambawala in Kilwa District. The purpose of the study was to assess the existing population status of the species in Tanzania. A total of 36 circular plots in Mitarure and 15 plots in each community forest were laid down. Data were recorded for the number of stems per plot, and then converted on per hectare basis where the basal area and densities per hectare were calculated. Data was disaggregated into 5 Diameter at Breast Height (DBH) generated distribution classes ranging from DBH 0 to more than 45 cm. The results revealed that, there was a contrast between the Mitarure Forest Reserve and community forests in terms of individual number of trees per unit area, basal area and densities. The numbers of stems per hectare for the species were found to be 16, 10 and 8 stems/ha in Mitarure, Ngea and Nambawala forest, respectively. <em>Dalbergia melanoxylon</em> in Mitarure forest was normally distributed. The respective basal area was over 80 m<sup>2</sup> per ha in Nambawala against over 60 in MFR and Ngea. The results suggest success of the communities in conserving the species after previous overharvest. Authorities should frequently visit forests to increase the population of the species and reduce unauthorised harvesting.</p> <p><strong>Keywords: </strong><em>Dalbegia melanoxylon</em>, Population structure, Mitarure forest reserve, Ngea and Nambawala community forests.</p> Agnes M.S. Nyomora Washa B. Washa Stephen I. Nnungu Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1442 1449 10.4314/tjs.v47i4.10 Advances in Nanomaterials Sciences and Nanotechnology for Sustainable Development: A Review https://www.ajol.info/index.php/tjs/article/view/216482 <p>The fields of materials sciences have great opportunities to address the challenges of sustainable development of modern societies. The sub-disciplines of materials sciences of interest in this review are nanomaterials sciences and nanotechnology. Nanomaterials possess one external dimension measuring 1-100 nm. They have larger surface area for the same mass than their bulk materials. They are more reactive with effects on their electrical, optical and magnetic properties. Thus, nanomaterials are promising for sustainable development in the areas of energy, water, chemicals, electronics, medical and pharmaceutical industries, CO2 mitigation and agriculture. To this end, this review explores the advances in nanomaterials sciences, nanotechnology and the potential applications of nanomaterials for sustainable development. In this review, 73 peer reviewed articles and abstracts were retrieved. The review considered nanomaterials of carbon, inorganic materials, semiconductors, polymeric and lipid based materials. It has been found that nanomaterials sciences and nanotechnology is promising for potential applications in the areas of environmental remediation, energy, food, agriculture, industry, molecular biology, medicine and in pharmaceutical industries for sustainable development.</p> <p><strong>Keywords</strong>: nanomaterials sciences, nanotechnology, sustainable development</p> Gervas E. Assey Wilhelm S. Malasi Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1450 1463 10.4314/tjs.v47i4.11 A Mathematical Analysis of an In-vivo Ebola Virus Transmission Dynamics Model https://www.ajol.info/index.php/tjs/article/view/216498 <p>Ebola virus (EBOV) infection is a hemorrhagic and hazardous disease, which is among the most shocking threats to human health causing a large number of deaths. Currently, there are no approved curative therapies for the disease. In this study, a mathematical model for in-vivo Ebola virus transmission dynamics was analyzed. The analysis of the model mainly focused on the sensitivity of basic reproductive number, &nbsp;pertaining to the model parameters. Particularly, the sensitivity indices of all parameters of &nbsp;were computed by using the forward normalized sensitivity index method. The results showed that a slight change in the infection rate immensely influences &nbsp;while the same change in the production rate of the virus has the least impact on . Thus, , being a determining factor&nbsp; of the disease progression, deliberate control measures targeting the infection rate, the most positively sensitive parameter, are required. This implies that reducing infection rate will redirect the disease to extinction.</p> <p><strong>Keywords: </strong>Ebola virus infection, immune response, sensitivity index, mathematical model.</p> Seleman Ismail Adeline Peter Mtunya Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1464 1477 10.4314/tjs.v47i4.12 Impacts of Wood Fuel Uses on Forest Cover: The Case of Semiarid Areas in Northern Tanzania https://www.ajol.info/index.php/tjs/article/view/216499 <p>Satellite images for the years 1987, 1997, 2002 and 2017, and questionnaire surveys were used to assess energy sources and demands as well as the impacts of wood fuel use to forest cover changes in Meru and Mwanga Districts. The major energy sources identified in the study areas include cow dung cake, firewood, charcoal, biogas, and liquefied petroleum gas. The total energy demands from these sources were 1400, 6289, 724 and 21 kg per day, respectively. Analysis from Landsat images showed variations in forest cover. The areas covered with forests in Meru District were found to be 1510, 1723, 1612 and 1327 ha for 1987, 1997, 2002 and 2017, respectively. The changes observed in Mwanga District were 31705, 31988, 17939 and 30960 ha for 1987, 1997, 2002 and 2017, respectively. From the findings it was observed that, the ongoing use of wood fuel in semi-arid areas of Meru and Mwanga Districts could deplete forests completely. The study concludes that charcoal and firewood consumptions are real threats to the long-term persistence of forests in Tanzania and proposes the use of renewable energy such as biogas for alleviating forest losses.</p> <p><strong>Keywords: </strong>Biogas, energy sources, Satellite images</p> Debora J Mahushi Revocatus L Machunda Talam E Kibona Copyright (c) 2021 2021-10-28 2021-10-28 47 4 1478 1491 10.4314/tjs.v47i4.13