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Investigation of functional performance of treatment systems for textile wastewater in selected textile industries in Tanzania
Get PDFThis research article was published by IWA publishing, Volume 87, Issue 3Textile industrialization is an integral part of the economic growth in Tanzania. However, the corresponding wastewater from textile treat ment processes consists of dyes and auxiliaries associated with acute toxicological impacts. This necessitates an investigation of the
functional performance of the industrial treatment systems used before effluent discharge. The study primarily accesses the catalog of indus trial dyes and the functionality of the treatment system at Arusha, Morogoro and Dar es Salaam vis-à-vis the effluent physicochemical
properties. The analytical study reveals disperse (42%), vat (34%) and reactive (26%) as the most used industrial dyes. The physicochemical
properties of the quantified wastewater reveal a significant amount of and phosphorus which was consequent to the high turbidity, bio chemical oxygen demand (BOD) and chemical oxygen demand (COD) apart from the color at the different sampling points. Although the
treatability of the wastewater was 90% efficient using an activated carbon system (237.33 + 0.67 mg/L). Similarly, the use of aerated con structed wetlands shows efficiency in the remediation of the recalcitrant having a value of 12.13 + 0.89b mg/L (90%) and 13.22 +
0.15a mg/L (94%). Thereafter, needful recommendations were suggested based on the physicochemical properties of the textile wastewater
and to improve the functionality of the treatment systems in the respective industries
Integrating contact tracing and wholegenome sequencing to track the elimination of dog-mediated rabies: An observational and genomic study
Get PDFThis research article was published in eLife journal, Volume 12, 2023.Background:
Dog-mediated rabies is endemic across Africa causing thousands of human deaths annually. A One Health approach to rabies is advocated, comprising emergency post-exposure vaccination of bite victims and mass dog vaccination to break the transmission cycle. However, the impacts and cost-effectiveness of these components are difficult to disentangle.
Methods:
We combined contact tracing with whole-genome sequencing to track rabies transmission in the animal reservoir and spillover risk to humans from 2010 to 2020, investigating how the components of a One Health approach reduced the disease burden and eliminated rabies from Pemba Island, Tanzania. With the resulting high-resolution spatiotemporal and genomic data, we inferred transmission chains and estimated case detection. Using a decision tree model, we quantified the public health burden and evaluated the impact and cost-effectiveness of interventions over a 10-year time horizon.
Results:
We resolved five transmission chains co-circulating on Pemba from 2010 that were all eliminated by May 2014. During this period, rabid dogs, human rabies exposures and deaths all progressively declined following initiation and improved implementation of annual islandwide dog vaccination. We identified two introductions to Pemba in late 2016 that seeded re-emergence after dog vaccination had lapsed. The ensuing outbreak was eliminated in October 2018 through reinstated islandwide dog vaccination. While post-exposure vaccines were projected to be highly cost-effective (1657 per death averted) and by maintaining rabies freedom prevents over 30 families from suffering traumatic rabid dog bites annually on Pemba island.
Conclusions:
A One Health approach underpinned by dog vaccination is an efficient, cost-effective, equitable, and feasible approach to rabies elimination, but needs scaling up across connected populations to sustain the benefits of elimination, as seen on Pemba, and for similar progress to be achieved elsewhere
Fabrication of liposome-chitosa N-ZnO nanohybrid integrated with Carissa Spinarum extract for antibacterial application
Get PDFA Thesis Submitted in Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Life Sciences of the Nelson Mandela African Institution of Science and TechnologyInnovative biomaterials provide a stimulating and adaptable platform for the implementation
of new and more effective methods to prevent bacterial infection. Built on biomimetic inorganic hybrid material, Dual Nanohybrid Delivery System (DN-DS) has advantageous
properties for biomedical applications, such as the delivery of herbal formulations for the
treatment of bacterial infections.
Using microwave assisted extraction (MAE), the polyphenols of Carissa spinarum were
extracted. The Dual Nanohybrid Delivery System (LipCsP-ZnONPs)-CT was formed by
combining LipCsP-Chitosan and ZnO-Chitosan, which were both generated using different
methods of co-precipitation and ion gelation, respectively. A Zetasizer was used to characterize
the nanosystems' size, zeta potential, and polydispersity index (PDI). A UV-visible
spectrophotometer was utilized for the optical study, and a scanning electron microscope was
employed to investigate at the surface morphology. The interaction of coated chitosan with
liposomes and ZnONPs was evaluated using Fourier Transformation Infrared (FTIR)
spectroscopy. Different kinetic models were fitted to the results of the encapsulation and release
profiles of polyphenols in the liposome nanosystems to determine the mechanism of release.
Antibacterial activity of the nanoformulations was assessed by an agar diffusion assayand the
micro plate blue assay (MABA).
The Zeta potential of LipCsP changed from -45.3 ± 0.78 to +34.43 ±1.36 due to chitosan
coatings. Polyphenol-encapsulation efficiency was higher in LipCsP-Chitosan (81 ± 2.5%) than
in LipCsP (66.11 ± 1.11%). Conversely, the size of LipCsP (176.17 ± 1.05 nm) increasedto
365.2 ± 0.70 nm. FTIR analysis revealed the interaction of the liposome with chitosan due to
the disappearance of N-H primary amine. Interaction between chitosan and zinc oxide was
revealed by the formation of new absorption peaks at 670 cm-1
and 465 cm-1
as observed in the
FTIR analysis. (LipCsP-ZnONPs)-CT presented high bioaccessibility of polyphenols in the
simulated gastric phase (82.14 ± 0.80%) than in simulated intestinal phase (71.60 ± 0.86%), a
stable system for sustained release of polyphenols, and prominent antibacterial activity.
(LipCsP-ZnONPs)-CT exhibited a relative inhibition zone diameter (RIZD) of 89.60 ± 1.32,
significant high viability reduction (P˂0.05) against Klebsiella pneumoniae as compared to
LipCsP-Chitosan and ZnO-chitosan. The nanohybrid systems (LipCsP-Chitosan and ZnO chitosan) exhibited synergistic effect against Klebsiella pneumoniae. This study successfully
demonstrated the utility of the nanohybrid as a potential antibacterial agent against K.
ii
pneumoniae, therefore, the fabricated dual nano delivery system is an efficacy material for
treatment of pneumococcal infections
A Mixed Methods Exploration of the Role of Participation in a Nutrition-Sensitive Agroecology Intervention in Rural Tanzania
Get PDFThis research article was published in the Current Developments in Nutrition Volume 7, Issue 6, June 2023Background: Participation is key to the successful implementation of nutrition-related interventions, but it has been relatively overlooked.
Objective: We sought to describe participation intensity among smallholder farmers in a randomized nutrition-sensitive agroecology study
in rural Tanzania. We explored the association between baseline characteristics and overall participation intensity (quantitatively at the
individual level and qualitatively at the group level), the association of participation intensity with 2 process indicators, and the association
between participation intensity and key study outcomes.
Methods: Data came from 7 rounds of surveys with 295 women and 267 men across 29 months and 2 rounds of semi-structured interviews
with the 20 “mentor farmers” who delivered the intervention. Participation intensity was based on the number of months of attendance at
village-level project meetings or household visits (range: 0–29). Multivariable models of participation were built.
Results: Women and men participated for 17.5 7.2 and 13.6 8.3 months, respectively. Participation intensity followed 1 latent tra-
jectory: initially low, with a sharp increase after month 7, and plateaued after the first year. At baseline, higher participation intensity was
associated with older age, higher education, level of women’s empowerment, being in the middle quintile of wealth, and qualitatively,
village residence. Higher participation intensity was associated with 2 process indicators – better recall of topics discussed during meetings
and greater knowledge about key agroecological methods. High participation intensity was positively associated with increased use of
sustainable agricultural practices among all participants, and among women, with husband’s involvement in household tasks and child’s
dietary diversity score.
Conclusions: Participation intensity covaried with key study outcomes, suggesting the value of increased attention to implementation in
nutrition-related programs for providing insights into drivers of impact. We hope that investigations of participation, including participation
intensity, will become more widespread so that intervention impacts, or lack thereof, can be better understood
Effect of retaliatory killing on African lion coalitions in Tarangire-Manyara ecosystem, Tanzania
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Master’s in Life Sciences of the Nelson Mandela African Institution of Science and TechnologyIn landscapes where people and lions coexist, conflicts are common due to livestock predation
and threats to human safety. Retaliatory lion killing by humans is often a consequence of such
conflicts. In Tarangire-Manyara Ecosystem (TME) lion population are threatened by retaliatory
killing, but little is known how retaliatory killing affects lion social structure, particularly male
coalitions. Fourteen years dataset of lion monitoring was used to map the spatial-temporal
dynamics of male coalition. Lion killing data was used to assess the effects of retaliatory lion
killing on the male coalitions for ten prides. Interviews on two hundred and fourteen
respondents was used to assess the attitudes and awareness of the community on effects of
retaliatory killing to lions. Lion coalitions were found larger and lasted for a longer tenure
period in low-risk areas of retaliatory killing, and far from active hunting blocks. Twelves lions
were killed for livestock loss, while fifteen attempts of lion killing were prevented. Attitude
towards lion existence and conservation was positive for young people (18-35 years) compared
to older age class. People with primary or secondary level of education were more likely to
have lions killed if they attack livestock compared to people with no formal education.
Community attitude on retaliation effect varied widely, as people perceptions depends on
benefits/losses they incurred. This study showed retaliatory killing negatively affects long-term
lion coalition and population. Also, recommends implementing better education programs and
participatory conservation activities to protect the declining lion populations
Modeling and optimization of trivalent arsenic removal from wastewater using activated carbon produced from maize plant biomass: a multivariate experimental design approach
Get PDFThis research article was published by Springer Nature Limited in 2023Globally, both industrialized and developing nations struggle with the issue of water pollution due to heavy metals. Human life depends on water, and when it is contaminated with dangerous heavy metals like arsenic, people’s health suffers. The interactive influence of three independent sorption processes variables such as bio-adsorbent dosage (0.50–3.00 g/L), contact time (40.00–90.00 min), and initial concentration (10.00–30.00 mg/L) on the modeling and optimization of trivalent arsenic removal from wastewater was studied in a batch mode using multivariate experimental design. The quadratic models provided accurate predictions for the response variables with high coefficients of correlation of 0.9984 and 0.9994 for removal and uptake rates, respectively. The developed models were accurate and exhibited a remarkable correlation between the observed and projected data according to the diagnostic test analyses. Through the analysis of variance, all the studied adsorption factors were statistically significant (p-values < 0.0001) with initial concentration and bio-adsorbent dosage producing the main interactive effect on the percentage removal and adsorption capacity with F-values of 146.05 and 264.65, respectively. The optimum operating conditions attained were 90.00 min contact time, 0.50 g/L bio-adsorbent dosage, and an initial concentration of 10.00 mg/L, which gave arsenic maximum removal and uptake efficiencies of 93.14% and 7.04 mg/g, correspondingly with the desirability of 0.844. Confirmative tests were conducted under the optimized conditions to validate the accuracy of the models in which a maximum removal efficacy of 94.33% and adsorption capacity of 7.15 mg/g were achieved. The applicability of the bio-adsorbent in the adsorption of arsenic in textile industrial wastewater was also tested and the bio-adsorbent could competitively decontaminate over 99% of arsenic species from the wastewater
Prevalence and correlates of overweight and obesity among primary school children in Ilala and Mkuranga districts, Tanzania
Get PDFA thesis Submitted in Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Life Sciences of the Nelson Mandela African Institution of Science and TechnologyOverweight and obesity are increasing among school children and are currently considered as
significant public health problems. Therefore, this study aimed to determine the prevalence of
overweight and obesity in school children (10-13 years) and their correlates, to inform policy
for action in order to reduce the magnitude and consequences of the problems. A cross sectional study design was conducted in Ilala and Mkuranga districts of Tanzania between July
2019 and December 2020 among 406 school children, 36 parents/guardians, and 9 teachers.
Standardized questionnaires were used for data collection and laboratory analysis was
performed to determine actual fatty acids and sugar contents of foods commonly consumed by
school children in the study areas. Height and weight measurements were performed by using
the World Health Organization standard procedures. The general prevalence of overweight and
obesity based on BMI-for-age indicator was 22.6% higher in private than in public schools
(32.4% vs. 14.8%, p<0.001). Dietary habits of school children were characterized by low fruit,
vegetable, and milk intake. Overweight and obesity among school children correlated
significantly with moderate consumption of soda/carbonated drinks (AOR 0.38, 95% CI 0.19-
0.85), high consumption of fruit/fruit-flavored juices (AOR 0.21, 95% CI 0.07-0.67), local ice
cream (AOR 0.41, 95% CI 0.17-0.95), and low dietary diversity (AOR 0.57, 95% CI 0.44-
0.75). Other predictors were moderate consumption of potato chips (AOR 2.27, 95% CI 1.07-
4.81) and having overweight/obese parent (AOR 10.11, 95% CI 2.72-37.65). In addition,
sedentary behavior, such as listening to music and/or radio for >2 hours/week (OR 2.7, 95%
CI 1.2-6.1) and low physical activity such as walking for exercise <2 hours/week (OR 2.1, 95%
CI 1.1-4.1) were risk factors for overweight/obesity while rope skipping for >2 hours/week
(OR 0.14, 95% CI 0.03-0.7) was protective. Saturated fatty acids, such as palmitic acid (C16:0),
were found in abundance in all food samples while sucrose and saccharin concentrations varied
considerably between products. Findings from this study showed that the food environment
may be a contributing factor to overweight/obesity among school children. This study informs
relevant authorities to take appropriate actions to minimize health risks associated with
overweight and obesity in school children
Common predators and factors influencing their abundance in Anopheles funestus aquatic habitats in rural south-eastern Tanzania
Get PDFThis research article was published in PLOS ONE, 2023.Background
The role of larval predators in regulating the Anopheles funestus population in various
malaria-endemic countries remains relatively unknown. This study aimed to investigate the
common predators that co-exist with Anopheles funestus group larvae and evaluate factors
that influence their abundance in rural south-eastern Tanzania.
Methods
Mosquito larvae and predators were sampled concurrently using standard dipper (350 ml)
or 10 L bucket in previously identified aquatic habitats in selected villages in southern Tan zania. Predators and mosquito larvae were identified using standard identification keys. All
positive habitats were geo-located and their physical features characterized. Water physico chemical parameters such as dissolved oxygen (DO), pH, electrical conductivity (EC), total
dissolved solids (TDS) and temperature were also recorded.
Results
A total of 85 previously identified An. funestus aquatic habitats in nine villages were sampled
for larvae and potential predators. A total of 8,295 predators were sampled. Of these Coena grionidae 57.7% (n = 4785), Corixidae 12.8% (n = 1,060), Notonectidae 9.9% (n = 822),
Aeshnidae 4.9% (n = 405), Amphibian 4.5% (n = 370), Dytiscidae 3.8% (n = 313) were com mon. A total of 5,260 mosquito larvae were sampled, whereby Anopheles funestus group
were 60.3% (n = 3,170), Culex spp. 24.3% (n = 1,279), An. gambie s.l. 8.3% (n = 438) and
other anophelines 7.1% (n = 373). Permanent and aquatic habitats larger than 100m2 were
positively associated with An. funestus group larvae (P<0.05) and predator abundance(P<0.05). Habitats with submerged vegetation were negatively associated with An. funestus
group larvae (P<0.05). Only dissolved oxygen (DO) was positively and significantly affect
the abundance of An. funestus group larvae (P<0.05). While predators’ abundance was not
impacted by all physicochemical parameters.
Conclusion
Six potential predator families were common in aquatic habitats of An. funestus group lar vae. Additional studies are needed to demonstrate the efficacy of different predators on lar val density and adult fitness traits. Interventions leveraging the interaction between
mosquitoes and predators can be established to disrupt the transmission potential and sur vival of the An. funestus mosquitoe
Conceptualization of groundwater-surface water interaction with evidence from environmental isotopes and hydrogeochemistry in lake Babati Basin in Northern Tanzania
Get PDFThis research article was published by Elsevier in 2023The holistic management of water resources is attainable with evidence-based planning constructed on reliable hydrological information. However, data paucity, especially in sub-Saharan Africa, leads to a significant knowledge gap regarding surface water and groundwater interactions, leaving considerable uncertainty to support relevant decisions. This study combined hydrogeochemistry and environmental isotopes to explore the connections between the surface water and groundwater in the data scarce catchment of Lake Babati Basin in northern Tanzania. The results showed that: i) Lake Babati receives groundwater influx from recently recharged aquifers endowed in the pyroclastic formation in the lake basin; ii) the lake is not well mixed as presented by the heterogenous hydrogeochemistry and confirmed by the differences in the isotopic composition of deuterium and oxygen – 18 at different locations within it; iii) the deep wells located near the lake abstract a mixture of recently recharged water, deep aquifer waters and lake water with enriched isotopic compositions; and iv) the hydrogeochemistry and isotopic data reveal the presence of a hydraulic connection between the lake and deep wells. The findings of this study demonstrate that the catchment, the groundwater system, and Lake Babati are interlinked and, therefore, require the implementation of integrated water resources management to enhance sustainable development
The Effect of Hyperparameter Optimization on the Estimation of Performance Metrics in Network Traffic Prediction using the Gradient Boosting Machine Model
Get PDFA research article was submitted to Engineering, Technology & Applied Science Research (ETASR) Volume: 13 | Issue: 3 ,June 2023 |Information and Communication Technology (ICT) has changed the way we communicate and access information, resulting in the high generation of heterogeneous data. The amount of network traffic generated constantly increases in velocity, veracity, and volume as we enter the era of big data. Network traffic classification and intrusion detection are very important for the early detection and identification of unnecessary network traffic. The Machine Learning (ML) approach has recently entered the center stage in network traffic accurate classification. However, in most cases, it does not apply model hyperparameter optimization. In this study, gradient boosting machine prediction was used with different hyperparameter optimization configurations, such as interaction depth, tree number, learning rate, and sampling. Data were collected through an experimental setup by using the Sophos firewall and Cisco router data loggers. Data analysis was conducted with R software version 4.2.0 with Rstudio Integrated Development Environment. The dataset was split into two partitions, where 70% was used for training the model and 30% for testing. At a learning rate of 0.1, interaction depth of 14, and tree number of 2500, the model estimated the highest performance metrics with an accuracy of 0.93 and R of 0.87 compared to 0.90 and 0.85 before model optimization. The same configuration attained the minimum classification error of 0.07 than 0.10 before model optimization. After model tweaking, a method was developed for achieving improved accuracy, R square, mean decrease in Gini coefficients for more than 8 features, lower classification error, root mean square error, logarithmic loss, and mean square error in the model