Tanzania Journal of Science最新文献_第7页

Simulation of Mathematical Model of Network Interference on Global System for Mobile Communication 移动通信全局系统网络干扰数学模型仿真

Tanzania Journal of Science Pub Date : 2023-03-31 DOI: 10.4314/tjs.v49i1.5

Y. O. Aderinto, Y. Musa

引用次数: 0

Ethanol Extracts from Selected Tanzanian Medicinal Plants Selectively Inhibit Plasmodium falciparum Growth In Vitro 坦桑尼亚药用植物乙醇提取物对恶性疟原虫体外生长的选择性抑制

Tanzania Journal of Science Pub Date : 2023-03-31 DOI: 10.4314/tjs.v49i1.4

R. Christopher, Amina Msonga, H. Hoppe, F. Boyom

{"title":"Ethanol Extracts from Selected Tanzanian Medicinal Plants Selectively Inhibit Plasmodium falciparum Growth In Vitro","authors":"R. Christopher, Amina Msonga, H. Hoppe, F. Boyom","doi":"10.4314/tjs.v49i1.4","DOIUrl":"https://doi.org/10.4314/tjs.v49i1.4","url":null,"abstract":"This study aimed to assess the in vitro antiplasmodial and cytotoxic activities of ethanol extracts from the root barks, leaves and stem barks of seven medicinal plant species growing in Tanzania. The antiplasmodial activities of extracts against chloroquine-sensitive (3D7) and multidrug-resistant (Dd2) strains of Plasmodium falciparum were determined using a SYBR green I-based fluorescence assay, while the cytotoxicity of active extracts was determined against the human HepG2 cell line using a resazurin-based assay. Out of twenty-one extracts screened, two of them, namely, DFRE from Dracaena fragrans root bark (IC50Pf3D7 = 2.4 mg/mL) and EHSE from Erythrina haerdii stem bark (IC50Pf3D7 = 8.6 mg/mL and IC50PfDd2 = 7.6 mg/mL), exhibited good potencies against P. falciparum parasites. The two extracts emerged as the most promising and selective inhibitors (inhibited the growth of P. falciparum strains and were not toxic to the human HepG2 cell line) of chloroquine-sensitive (3D7) and multidrug-resistant (Dd2) strains of P. falciparum. Eight other extracts showed moderate potencies with IC50 values ranging from 11–25 mg/mL against both plasmodial strains, while the remaining 11 extracts were mildly active with IC50 values ranging from 25.1 to 96.7 mg/mL. The results of the cytotoxicity test indicated that the median cytotoxic concentrations (CC50) of the tested extracts were all ≥ 224.8 mg/mL, leading to selectivity indices (SI) > 10-fold for most of the extracts. The findings described in this article support the traditional use of the investigated medicinal plants to treat malaria. \u0000Keywords: Antiplasmodial; Cytotoxicity; Ethanol extracts; Plasmodium falciparum \u0000 ","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73626588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Measurement of Solar Irradiance for Determining the Optimal Tilt Angle for Photovoltaic Panels 确定光伏板最佳倾斜角的太阳辐照度测量

Tanzania Journal of Science Pub Date : 2023-03-31 DOI: 10.4314/tjs.v49i1.23

G. I. Olatona, Tolulope J. Fadairo

{"title":"Measurement of Solar Irradiance for Determining the Optimal Tilt Angle for Photovoltaic Panels","authors":"G. I. Olatona, Tolulope J. Fadairo","doi":"10.4314/tjs.v49i1.23","DOIUrl":"https://doi.org/10.4314/tjs.v49i1.23","url":null,"abstract":"The challenge of solar panel installers in determining the tilt angle needed to obtain optimal performance from the photovoltaic panels was the focus of this paper. The performances of two 150 W panels under varied conditions of temperature and solar irradiance on a plane at two different heights (1 m and 11.5 m) from the ground surface were determined to find the effects of tilt angle and altitude on their performances. Measurements of solar irradiance, temperature, open-circuit voltage, and short circuit current were made at various tilt angles and compared to one another based on the measured irradiance. The optimal tilt angle at the experimental site was found to be 15°SW (165°). At this angle, the irradiance was 818.05 Wm–2 compared to 792.26 Wm–2 at 15°NE (15°), 780.44 Wm–2 45°NE (45°) and 767.63 Wm–2 at 45°SW(135°) at 1 m from ground surface, while at 11.5 m the irradiance at 15°SW was 861.99 Wm–2 compared to 685.98 Wm–2 at 15°NE, 624.33 Wm–2 at 45°NE and 676.49 Wm–2 at 45°SW. Hence the performance of a photovoltaic panel solely depends on the tilt angles relative to the height at which the panel is mounted. \u0000Keywords: Solar, Irradiance, Photovoltaic, Panels, Tilt angle","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90618333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effects of Vacuum Packaging and Chilling Storage on the Microbiological Changes of the Superheated Steam Dried Sardines 真空包装和冷藏对过热蒸干沙丁鱼微生物变化的影响

Tanzania Journal of Science Pub Date : 2023-03-31 DOI: 10.4314/tjs.v49i1.13

Prissillah Antelm, I. Juma, L. Rweyemamu, L. D. Kaale

{"title":"Effects of Vacuum Packaging and Chilling Storage on the Microbiological Changes of the Superheated Steam Dried Sardines","authors":"Prissillah Antelm, I. Juma, L. Rweyemamu, L. D. Kaale","doi":"10.4314/tjs.v49i1.13","DOIUrl":"https://doi.org/10.4314/tjs.v49i1.13","url":null,"abstract":"Fish are important sources of protein and micronutrients for combating malnutrition. Since fish are highly perishable, methods for processing and preserving them should be the main focus to increase their shelf life and maintain their quality. The present study assessed the effectiveness of the superheated steam dryer (SSD) in processing sardines, and examined the effects of packaging and storage conditions on their microbiological quality. Sardines collected from the Mafia Island were dried in SSD, air-packed and stored at room temperature (AR), air-packed and stored at chilling temperature (AC), vacuum-packed and stored at room temperature (VR), and vacuum-packed and stored at chilling temperature (VC) for 49 days. Following drying, the total viable bacterial counts (TVBC) and total yeast and mould counts (TYMC) both decreased from the initial values of 9.14 (TVBC) and 2 (TYMC) log CFU/g in the fresh samples to 0.00 log CFU/g. The AR samples had the highest microbial growths during storage (7.48 (TVBC) and 2.82 (TYMC) log CFU/g), whereas the VC samples had the lowest (1.79 (TVBC) and 1.42 (TYMC) log CFU/g). The AR treatment was rejected within 21 days, whereas the AC, VR, and VC treatments prolonged the sardines’ shelf life throughout the storage time. \u0000Keywords: Superheated steam dryer, sardine, microbial analysis, vacuum packaging, chilling storage","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85658809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Semi-Analytic Approach to Solving Rosenau-Hyman and Korteweg-De Vries Equations Using Integral Transform 利用积分变换求解Rosenau-Hyman和Korteweg-De Vries方程的半解析方法

Tanzania Journal of Science Pub Date : 2023-03-31 DOI: 10.4314/tjs.v49i1.3

Adedapo Chis Loyinmi, K. O. Idowu

引用次数: 1

Generation of Electricity by Using Microbial Fuel Cell Prototype Fed by Sewage: Case Study at the University of Dar es Salaam 利用污水供给的微生物燃料电池原型发电:达累斯萨拉姆大学的案例研究

Tanzania Journal of Science Pub Date : 2023-03-31 DOI: 10.4314/tjs.v49i1.21

Mahir M Said, Asia A Saad, G. John, Aviti Thadei Mushi

{"title":"Generation of Electricity by Using Microbial Fuel Cell Prototype Fed by Sewage: Case Study at the University of Dar es Salaam","authors":"Mahir M Said, Asia A Saad, G. John, Aviti Thadei Mushi","doi":"10.4314/tjs.v49i1.21","DOIUrl":"https://doi.org/10.4314/tjs.v49i1.21","url":null,"abstract":"The access to electricity is still not reliable in Tanzania. Whilst, there are several locations within the country that have wastewater cites that are not economically used to produce electricity. At the University of Dar es Salaam (UDSM), there are main grid power, and few scattered solar panels. This study was intended to bridge the divide between the current increasing power demands of the UDSM by exploiting not so much used sources, such as electric energy from wastewater. This study was undertaken to develop a Microbial Fuel Cell (MFC) prototype fed by sewage in Dar es Salaam, for electricity generation using cost effective materials for the cathode compartment. The collection of samples took place using sewage substrates from the UDSM oxidation ponds. The untreated sewage was collected from oxidation ponds. Preliminary experiments were carried out to identify the cathode and substrate that produced better results in terms of volts and current output. Aluminium produced the most desirable results compared to copper, stainless steel and mild steel in all the substrates. On the other hand, untreated sewage with aluminium/carbon electrodes produced higher voltage and current compared to treated sewage with the same electrodes. Thereafter, a prototype of the MFC was developed by connecting three single chambered cells in series of 628 cm3 volume of untreated sewage with aluminium and carbon electrodes. The prototype generated a stable voltage of 1.73 V and a current of 0.07 mA recorded for a period of one hour. The power generated was enough to light a 6.25 mW LED bulb of 25 mA across a 100 Ω resister. Therefore, untreated sewage produced more power in MFCs with aluminium/carbon electrodes compared to the other tested materials. \u0000Keywords: Aluminium electrodes, charcoal electrode, alternative energy source, wastewater","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83352799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Geo-Statistical Analysis of Meteorological Drought and Recurrence Intervals in the Context of Climate Change Over Extreme Northeastern Region of Nigeria 气候变化背景下尼日利亚东北部极端地区气象干旱及其重现期的地质统计分析

Tanzania Journal of Science Pub Date : 2023-03-31 DOI: 10.4314/tjs.v49i1.14

I. B. Abaje

{"title":"Geo-Statistical Analysis of Meteorological Drought and Recurrence Intervals in the Context of Climate Change Over Extreme Northeastern Region of Nigeria","authors":"I. B. Abaje","doi":"10.4314/tjs.v49i1.14","DOIUrl":"https://doi.org/10.4314/tjs.v49i1.14","url":null,"abstract":"This study examined the occurrence of meteorological drought in the context of climate change over the extreme northeastern region of Nigeria using rainfall and temperature data spanning a period of 60 years (1961-2020) and 40 years (1981-2020), respectively. Linear regression, 5-year moving average and Cramer’s test were used to examine the changes in the rainfall and temperature. Rainfall Anomaly Index was used in depicting periods of different drought intensities in the region. The trend analysis of the climate data revealed that the region has been experiencing increasing rainfall and temperature in recent years. Findings also revealed that the droughts of the 1980s were more severe than the Great Sahelian Droughts of 1968-1973. The year 1987 was the driest in the whole period of study (1961–2020). Contrariwise, about 81% of the region from 2000 to 2020 experienced normal to very wet conditions. The mean probabilities of mild, moderate, and severe droughts in the area were 0.14 (recurrence interval of 8 years), 0.11 (recurrence interval of 11 years), and 0.07 (recurrence interval of 16 years), respectively. This study concludes that the number of drought occurrences has decreased in recent years. Therefore, government policies related to agriculture and water resources development in the area should take into account the increasing rainfall and temperature in recent years. \u0000Keywords: Climate Change, Meteorological drought, Rainfall, Recurrence Interval, Severe Drought, Temperature","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73270436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effects of Climate Change, Land Use and Land Cover Variability on Green and Blue Water in Wami/Ruvu Basin, Tanzania 气候变化、土地利用和土地覆盖变率对坦桑尼亚Wami/Ruvu盆地绿蓝水的影响

Tanzania Journal of Science Pub Date : 2023-03-31 DOI: 10.4314/tjs.v49i1.22

Benson HM Lazaro, M. Hagai, Rubhera Ram Mato

{"title":"Effects of Climate Change, Land Use and Land Cover Variability on Green and Blue Water in Wami/Ruvu Basin, Tanzania","authors":"Benson HM Lazaro, M. Hagai, Rubhera Ram Mato","doi":"10.4314/tjs.v49i1.22","DOIUrl":"https://doi.org/10.4314/tjs.v49i1.22","url":null,"abstract":"Water basins are the primary food sources, giving green water and blue water worldwide. Despite the basins’ potential, information on the periodical variations in blue water and green water is sparse, particularly in developing countries. The study specifically evaluated the changes in land use and land cover variability (LULCV), effects of land use and land cover variability on green water and blue water variations, and effects of climatic changes on green water and blue water. The evaluation involved the Enhanced Thematic Mapper and Operational Land Imager satellite images of 1990, 2000, 2010 and 2020. Image processing utilized the Soil and Water Assessment Tool (SWAT) in ArcGIS software. The land use and land cover variabilities indicated that land use supporting social-economic activities increased, while natural land cover decreased. Proportionally, blue water per annum was decreasing due to declining natural vegetation, enhanced by the increased socio-economic activities. Whereas, the increase in green water per annum was due to the increased temperatures, boosted by climate changes. Since the temperature rise is mainly uncontrolled, greenhouse farming should be encouraged for making green water more productive in agriculture and communities should be encouraged to practice environmentally friendly anthropogenic activities for sustainable green water and blue water management. \u0000Keywords: Basin, Green water, Blue water, SWAT model, Climate change","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89403865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Dosimetric Comparison Between Two and Six Beams Conformal Radiotherapy Plans for Paediatric Wilm's Tumour Patients at Ocean Road Cancer Institute, Tanzania 坦桑尼亚海洋路癌症研究所儿童Wilm肿瘤患者二束和六束适形放疗方案的剂量学比较

Tanzania Journal of Science Pub Date : 2023-03-31 DOI: 10.4314/tjs.v49i1.10

R. M. Mruma, N. Dharsee, Christina V Malichewe, J. D. Kisukari, Geofrey F. Soko, Hemed S. Myanza, Furahini Yoram

{"title":"Dosimetric Comparison Between Two and Six Beams Conformal Radiotherapy Plans for Paediatric Wilm's Tumour Patients at Ocean Road Cancer Institute, Tanzania","authors":"R. M. Mruma, N. Dharsee, Christina V Malichewe, J. D. Kisukari, Geofrey F. Soko, Hemed S. Myanza, Furahini Yoram","doi":"10.4314/tjs.v49i1.10","DOIUrl":"https://doi.org/10.4314/tjs.v49i1.10","url":null,"abstract":"This study aimed to compare the dose distributions of three-dimensional conformal treatment planning using two and six radiation beams among paediatric patients receiving radiotherapy for Wilms tumour at Ocean Road Cancer Institute. CT scans of 53 patients were used to generate 106 treatment plans, 53 plans for two beams, and 53 plans for six beams. Planning target volumes and organs at risk parameters were compared between both plans using paired samples t-test. A p-value < 0.05 was considered statistically significant. The findings showed that the D95% and Dmean of the target are better with six beams than with the two-beam plans (p ˂ 0.001). The conformity index and monitor unit are significantly better with two-beam plans than with six-beam plans (p ˂ 0.001). No volume of the contralateral kidney received more than 12 Gy for both two and six plans. There were no differences in Dmax for the spinal cord (p = 0.208), while Dmean was observed to be lower in two compared to six beams (p ˂ 0.001) for the liver. Six beam plans have good target coverage, while two beam plans have good conformity index and monitor unit. The observed doses to the organs at risk in both plans were lower than their normal tolerance. \u0000Keywords: Wilm's tumour, Three-dimensional conformal radiotherapy, whole abdomen radiotherapy, paediatric radiotherapy, Dosimetry","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77677141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Polyphenolic Content and Radical Scavenging Activities of the Peel, Pulp and Seed of Avocado (Persea americana Mill.) Grown in Tanzania 鳄梨果皮、果肉和种子的多酚含量及自由基清除活性研究产自坦桑尼亚

Tanzania Journal of Science Pub Date : 2023-03-31 DOI: 10.4314/tjs.v49i1.20

I. Juma, J. Englund, R. Ortiz, M. Geleta, D. Tibuhwa, A. Carlsson, A. Nyomora, Moneim Fatih, H. P. Hovmalm

{"title":"Polyphenolic Content and Radical Scavenging Activities of the Peel, Pulp and Seed of Avocado (Persea americana Mill.) Grown in Tanzania","authors":"I. Juma, J. Englund, R. Ortiz, M. Geleta, D. Tibuhwa, A. Carlsson, A. Nyomora, Moneim Fatih, H. P. Hovmalm","doi":"10.4314/tjs.v49i1.20","DOIUrl":"https://doi.org/10.4314/tjs.v49i1.20","url":null,"abstract":"Avocado is a healthy fruit and the consumption is continuously growing worldwide. The fruit contains polyphenolic compounds with antioxidant effects. Globally, research has been devoted to exploring the fruit quality, especially compounds with antioxidant effects, from different avocado-growing sites. However, the fruit quality of the Tanzanian avocado has so far not been investigated. In this study, the contents of polyphenols in peel, pulp and seed of avocados sampled in south-western Tanzania are described. The levels of total polyphenolic and flavonoid contents were measured, and antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The total polyphenolic content was highest in the seed and lowest in the peel (424 and 200 mg GAE/100 g DW, respectively). As for the total flavonoid content, the pulp had the highest value of 36.98 mg RE/100 g DW, while the seed had the lowest value of 32.54 mg RE/100 g DW. The overall average half maximal effective concentration (EC50) values in decreasing order, corresponding to an increasing antiradical activity, were 4.90 (peel), 3.63 (seed) and 3.24 µg/mL (pulp). The seed and peel possessed high levels of total polyphenolic and flavonoid content, thus demonstrating substantial antioxidant capacity. Seed and peel can potentially be processed and included in the diet to provide inexpensive antioxidant ingredients of natural origin. Consumption of the seed will not only improve human health but also reduce the environmental pollution, as many thousand tonnes of avocado seeds are produced in Tanzania per year; a huge amount currently remains as waste. \u0000Keywords: Flavonoid contents; Free radicals; EC50; Polyphenolic content","PeriodicalId":22207,"journal":{"name":"Tanzania Journal of Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75512806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0