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Hydrological modeling of artificial recharge of groundwater for sustainable water supply in Dodoma city
Get PDFA Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of
Master’s of Science in Mathematical and Computer Science and Engineering of the
Nelson Mandela African Institution of Science and TechnologyThe growing human population in Dodoma City has resulted in high demand for water use,
which has led to the overexploitation of groundwater in Makutupora aquifer. Therefore, this
study was carried out to model artificial recharge to replenish groundwater in the Makutupora
aquifer to ensure water supply sustainability in the City. The simulation was done in Modular
finite-difference flow model (MODFLOW) with the support of ModelMuse and the calibration
was done using 21 piezometers. The Geographical Information System (GIS) technique used
in preparing the shapefiles and calculation of groundwater storage capacity. The results
indicated that the total groundwater storage in the Makutupora aquifer was about 247.84
Million Cubic Meters (MCM). After simulation of the steady-state reference period, the other
four stress periods were simulated, considering the projected population and water demand.
The planned injection wells to the model in the first, second, third, and fourth transient state
periods resulted in a safe yield of 168 857 m3
/day, 197 760 m3
/day, 360 000 m3
/day, and 600
430 m3
/day, respectively. The recommended artificial recharge source is water from the
Kinyasungwe river that flows during rainfall time, generally from November to May. One of
the recorded years (2007) indicated a flow of up to 23.646 Million Cubic Meters (MCM). The
recommended artificial recharge is possible due to the aquifer storage capacity of 247.84
(MCM). Therefore, information from this study could be used by engineers when constructing
artificial engineering structures to replenish the water pumped from the Makutupora aquifer
Expression analysis of p16 and TOP2A protein biomarkers in cervical cancer lesions and their correlation with clinico-histopathological characteristics in a referral hospital, Tanzania
Get PDFThis research article published by PLOS ONE, 2021Introduction
Biomarkers yield important information for early diagnosis of cervical cancer. However, they
are rarely applied for prognosis of cervical cancer in Tanzania, where visual inspection
assay with acetic acid or Lugol’s iodine and Pap test are being used as the standard screening/ diagnostic methods.
Methods
This was a retrospective hospital-based cross-sectional study that was conducted to assess
cyclin-dependent kinase inhibitor (p16) and topoisomerase II-alpha (TOP2A) proteins
expression among women seeking cervical cancer care at Kilimanjaro Christian Medical
Centre, Tanzania between May 1, 2017 and May 10, 2018. Immunohistochemistry technique was used to detect the expressions of p16 and TOP2A proteins from the retrieved formalin-fixed and paraffin-embedded (FFPE) cervical biopsies.
Results
A total of 145 patients, with a mean age of 52.1 ± 12.9 years, were included in this study.
Upon immunohistochemistry staining, 103 (71.0%) and 90 (62.1%) were p16 and TOP2A
positive respectively. There was a strong association between histopathological class and
p16/TOP2A expression levels (Fisher’s exact test, p<0.001). Moreover, there was a strong
positive correlation between p16/TOP2A and cancerous cervical lesions (Spearman’s rank
correlation coefficients = 0.833 and 0.687, p = 0.006 and 0.005, respectively). The ageadjusted odds ratio for predicting cervical cancer lesions were independently significant for
p16/TOP2A biomarkers in FFPE cervical tissues [p16: OR = 1.142 (95% CI: 1.059–1.232,
p<0.001) and TOP2A: OR = 1.046 (95% CI: 1.008–1.085, p = 0.015)]. Importantly, thediagnostic performance of p16 was higher than that of TOP2A in the diagnosis of cancerous
lesions from non-cancerous cervical lesions (sensitivity: 97.2% versus 77.6%, accuracy:
92.8% versus 87.8%, respectively).
Conclusion
Our study has highlighted that over-expression of TOP2A is related to the grade of cervical
intraepithelial neoplasia but does not predict prognosis in cervical cancer. Similarly, expression of p16 is related to degree of histological dysplasia and malignancy, suggesting its
prognostic and predictive value in the management of cervical cancers. Further bigger studies are needed to validate their applications in the early diagnosis of cervical cancer
Molecular modification of dye constituents through grafting anchoring groups and pi-spacers: towards DSSCs application
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of
Doctor of Philosophy in Materials Science and Engineering of the Nelson Mandela
African Institution of Science and TechnologyTriphenylamine based dyes molecular modification by grafting anchoring groups and spacers
was
performed
within
computational
framework
aimed
at
potential
materials
for
dye-
sensitized solar cells (DSSCs) application. For the modification, benzothiadiazole-like
spacers, heterocyclic anchoring groups and heteroatom doping have been taken into account.
The reported structural and optoelectronic properties of the dyes were realized through
density functional theory and time-dependent density functional theory using B3LYP and
CAM-B3LYP functionals coupled with 6-31G(d,p) and 6-31G+(d,p) basis sets. The findings
show that presence of atoms of nitrogen and sulphur in the -spacers has a beneficial impact
on the material‟s properties, whereas the branched -spacer impairs the electronic light
absorption characteristics of the sensitizers. The heterocyclic anchoring units result in a
bathochromic shift with maximum absorption within 450 − 600 nm. The computed light harvesting
efficiencies, excited-state lifetimes, electron injection and regeneration abilities
prove that dyes with heterocyclic anchoring groups to be potential candidates for DSSC
applications. The heteroatom doping demonstrates that the chalcogens enhance the absorption
and fluorescent emission spectra of the isolated dyes in the visible and near infra-red regions
with maximum wavelength 504 – 556 nm and 637 – 732 nm, respectively. Simulation of the
dyes attachment to the TiO
2
surface was undertaken; two models of the crystal surface
considered, TiO
2
slab and hydrogenated (TiO
2
)
6
cluster. Among possible adsorption modes of
the dye@TiO
2
complexes, monodentate, bidentate and tridentate, the bidentate mode was
found thermodynamically more favourable. In both, individual dyes and dye@TiO
2
complexes, less electronegative dopants contributed to the improvement of the UV-Vis
spectra and redistribution of electron density. The calculated energies of the dye@TiO
2
attachment relate to dopant heteroatoms; stronger binding is observed in the complexes with
heavier heteroatoms – selenium and tellurium. The adsorption energy magnitudes range
between 0.11 − 1.75 eV for the TiO
2
slab and 7.61 − 9.48 eV for (TiO
2
)
6
cluster. Energy
difference between the two binding models was found to correspond to the enthalpy of
sublimation of TiO
2
from the TiO
2
anatase. One can anticipate that systematic modification
of dyes‟ building blocks may lead to novel materials with suitable characteristics for
application in DSSCs
Variations in nutrient composition and oil stability of oyster nuts (telfairia pedata) across different agro- climatic conditions in Northern Tanzania
Get PDFA Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of
Master's in Life Sciences of the Nelson Mandela African Institution of Science and
TechnologyIn sub-Saharan Africa, nutrient deficiency remains a challenge. The challenge is partly due to
the underutilization of available nutrient sources and failure to optimize nutrients based on agroclimatic
conditions.
Oyster
nuts
(Telfairia
pedata)
are
the
under-utilized
oilseeds
with
promising
food
and
non-food
applications.
This
study investigated oyster nut's nutrient composition and
variations across different sites and elevation levels encompassing different agro-climatic
conditions. Additionally, the stability of crude oyster nuts oil, flaxseed oil, and sunflower oil
were compared. Fats were the most abundant contents of the nuts with 68%, followed by 25%
protein, 5% carbohydrates, and 2% ash. Fatty acid contents were dominated by linoleic acid
(47%), while magnesium was the most abundant mineral (150 mg/100 g). Protein and fat
contents increased significantly with declining elevations, while sites did not show any
significant effects. In contrast, linoleic acids and minerals such as magnesium (Mg) and
phosphorus (P) of the nuts decreased significantly in low elevations. Other nutrients such as
carbohydrates, potassium (K), palmitic acid, iron (Fe), and stearic acid in the nuts were not
significantly affected by neither site nor elevations. Finally, oyster nut oil produced high
peroxide value (PV) and free fatty acids (FFA) compared to flaxseed and sunflower oil at room
temperature. Our results highlight that oyster nuts oil stability should be improved before
storage. Likewise, in lower elevations associated with high temperature and low precipitation,
oyster nuts' quality is optimized. Hence, oyster nuts can improve nutritional status and income
generation to farmers and communities in Tanzania
Activity of extracts from selected Tanzanian spices on major fungal pathogens and blight diseases of Tomato
Get PDFA Thesis Submitted in Fulfilment of the Requirements for the Degree of Doctor of
Philosophy in Life Sciences of the Nelson Mandela African Institution of Science and
TechnologyTomato (Solanum lycopersicum L.) is affected by many fungal diseases and farmers rely on
synthetic pesticides for management. Detrimental effects associated with injudicious use of
chemical pesticides have caused a demand for alternative crop protection products. The
objective of this study was to evaluate the antifungal activity of selected spices against major
fungal pathogens and blight diseases of tomato. An ethnobotanical survey for ginger and
turmeric and evaluation of awareness of botanical pesticides use and collection of commonly
consumed spices was conducted in Tanzania. Ethanolic extracts from spices were prepared by
maceration and tested for antifungal activity in posisoned food bioassay against Phytophthora
infestans, Alternaria solani, Fusarium oxysporum f.sp. lycopersici and Pythium spp in vitro,
their effect on seed germination and efficacy on severity of early and late blight diseases of
tomato in. The most active extracts were fractionated in solvents with varied polarity, analyzed
for biochemical composition and tested for fungicidal activity. Results indicated that among
the tested spices, clove extract was the most active, inhibiting all the fungal pathogens (100%).
Combined effect of the most active extracts showed that clove combined with either ginger,
black pepper or turmeric inhibited growth of P. infestans (100%). The activity of solvent
fractions was lower compared to the crude ethanolic extracts, except for clove fractioned in n hexane which completely inhibited the growth of P. infestans. Therefore, the most active
compounds were better extracted in ethanol. Gas chromatography- mass spectrometry analysis
of the clove’s n- hexane fraction showed high abundance of eugenol (74%) which is likely to
be responsible for the high antifungal activity. High concentrations of the spice extracts
deterred and slowed germination but low concentrations stimulated seed germination of up to
98%. Under field conditions black pepper extract reduced severity of late blight by 40% while
clove extract reduced severity of early blight by 35% compared to the untreated control. The
findings herein are proof of activity of spice extracts under in vitro and field conditions. This
study recommends that the most active extracts be considered for development of a broad
botanical fungicide for management of fungal diseases of tomato
Mathematical models for the dynamics of health related risks associated with alcoholism and its control strategy in Tanzania
Get PDFA Thesis Submitted in Fulfilment of the Requirements for the Degree of PhD Degree in
Mathematical and Computer Science and Engineering of the Nelson Mandela African
Institution of Science and TechnologyAlcoholic behavior has continually posed health challenges in many communities for decades.
Referring to Tanzanian situation, this study presents a more realistic model for the dynamics of
health risks associated with alcoholism. The model considered a population proportion that has
social cultural protection from alcohol consumption. In the context of this study, such protec tion emanated from religious beliefs practiced in the country. Three versions of the model were
analyzed considering different model analysis scenarios: the basic model, fuzzy logic model,
and optimal control model. The equilibria of the basic model were obtained and their stability
analysis was performed. The Next Generation Matrix (NGM) approach was used to compute
the basic risk reproduction number of the basic model. The risk free equilibrium point of the ba sic model was proved to be globally asymptotically stable whenever the basic risk reproduction
ratio was less than unit and unstable otherwise. The sensitivity analysis of the basic risk repro duction number of the basic model and numerical simulation were carried out. Their results
revealed that deliberate intervention strategies and policies focused on discouraging alcoholic
behaviors on their onset during initiation stage were more effective than dealing with alcoholic
population proportions. The fuzzy logic based model analysis have confirmed this result where
uncertainty conditions were assumed in the measure of influence of alcoholic individua
Assessment of environmental enteric dysfunction (eed) in Healthy and undernourished children-a crosstalk between eed and stunting
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
TechnologyUndernutrition affects 20% of children under five in the developing world. Stunting is a
prevalent form of undernutrition. Global prevalence of stunting in 2019 was 21.4%, while
current Tanzania national average is 34%. Ruvuma is one of the regions with highest
prevalence of stunting (44%) in Tanzania. This dissertation involved studies on factors
responsible for the high prevalence of stunting in Ruvuma and their association with
environmental enteric dysfunction (EED) in children. The study included randomly and
conveniently sampled children below 5 years of age between April 2019 – January 2020 who
attended outpatient clinics at hospitals in Ruvuma. Among children in the cross-sectional
survey, 46% were females and 45.6% were stunted, while the case-control study had 42%
females, 78% stunted cases, and EED prevalence of 57%. Through bivariate analysis, stunting
was associated with gender (χ2 = 6.6759, df = 1, p = 0.009772), hand washing before food (χ2
=
5.1213, df = 1, p = 0.02363), location of hospital (χ2 = 3.851, df = 1, p = 0.04972) and use of
Municipal garbage collection system (χ2 = 3.6814, df = 1, p = 0.05502). Moreover, diarrhea
was associated with toilet sharing (χ2 = 5.4703, df = 1, p = 0.002), use of household’s toilet (χ2
= 4.0224, df = 1, p = 0.004) and rinsing child feces into toilet (χ2 = 3.6814, df = 1, p < 0.01).
Multivariate logistic regression analyses showed that, stunting risk increased with male gender
(OR (95%CI) = 1.7945 (1.1944 –2.712), age (OR (95%CI) = 1.3122 (1.1484 –1.507), and
decreased with hand washing before meal (OR (95%CI) = 0.5403 (0.3042 –0.940). Finally,
diarrhea risk increased with toilet sharing (OR (95%CI) = 2.154 (1.153 –3.953) and decreased
with child’s use of toilet (OR (95%CI) = 0.510 (0.259 –0.945). Our study generally revealed
important factors that determined observed high prevalence of stunting in Ruvuma. These
factors can be modified through health interventions to reduce the observed high prevalence.
Nevertheless, the association between EED and stunting is undeniable and needs further
assessment in a bigger study
Assessment of fluoride removal in a batch electro‒coagulation process
No full textA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of
Master’s Degree in Environmental Science and Engineering of the
Nelson Mandela African Institution of Science and TechnologyA presence of excessive amounts of fluoride than the prescribed standards has been reported
in sources of domestic water supply around mount Meru slopes and other parts in Tanzania
while efforts to remove the excessive fluoride was carried out using various technologies and
materials. This study was perfomed to understand the fluoride removal effeciency of the
electrocoagulation technique. It has been reported that in the electrocoagulation process, ions
removal efficiency depends on the electrolysis time, voltage, pH and initial ions concentration
applied. In this electrocoagulation process, experiments were carried out to examine its
efficiency on removal of fluoride ions. The fluoride concentration tested ranged from 1.37 to
48 mg/L in both synthetic and natural waters. The voltage applied for the electrocoagulation
process ranged from 0 to 50 V while maintaining an optimal pH of 4 to 9. Experimental results
showed the removal efficiency of 90% with an optimal time of 30 minutes, at an applied voltage
of 20 V and a pH of 6 at initial concentration of 29.5 mg/L at 300 ml. The method showed
efficient removal of fluoride in water to achieve the allowable limits by the World Health
Organization and Tanzania Bureau of Standards (1.5 mg/L). At this voltage (30 V), the process
could be inferred to have the capability of treating the water and hence rendering such water
safe for use as reported previously
Screening local cereal-based beverages in Tanzania for yeast contaminants
Get PDFThis research article published by International Journal of Biosciences, Vol. 18, No. 2, 2021During spontaneous fermentation of cereals; yeasts ferment carbohydrates to produce alcohol and they also
provide vitamins, amino acids, peptides, and nucleotides needed by lactic acid bacteria as well as produce flavour
compounds. Nevertheless, spontaneous fermentation is prone to yeast contamination from the surroundings
which pose a health risk of opportunistic yeast infection. A study was carried out involving culturing, isolation
and identification of yeast contaminants present in the local cereal-based beverages namely Kindi, Kimpumu,
Togwa and Mbege purposively sampled and collected from Morogoro, Mbeya and Kilimanjaro regions in
Tanzania between February and May 2019. The results disclosed 24% of the yeasts actively involved in the
fermentation were opportunistic and identified as Candida zeylanoides, Candida albicans, Cryptococcus gattii,
Rhodotorula minuta, Candida ciferrii, and Candida dubliniensis. Such contamination levels from the studied
samples sets a base for further research to establish mechanisms of reducing exposure of cereal-based beverage
consumers to pathogenic effects of the opportunistic yeasts which may include infections by Candida spp
Mathematical modeling for helminths and mycobacterium tuberculosis co-infection
Get PDFA Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy in Mathematical and Computer Sciences and Engineering of the Nelson Mandela African Institution of Science and TechnologyTuberculosis continues to be a life-threatening disease in Sub-Saharan African countries despite the
available vaccine whereas soil-transmitted helminth is among the neglected tropical disease that
causes threats to pre-school, school-aged children and child-bearing mothers. The infection by
helminths increases susceptibility to tuberculosis. Thus, there is a need to investigate the possi bility of co-infection of the two diseases due to its geographical overlap at cellular and population
levels. This dissertation presents deterministic mathematical models that are aimed at describing the
transmission dynamics of soil-transmitted disease and the co-infection with tuberculosis. The first
model that describes the transmission dynamics of soil-transmitted helminth with optimal control is
presented. The model was qualitatively analyzed and the threshold that governs the spread of the
disease derived. The best control model was developed, and numerical simulations were run using
a variety of control measures to determine the most cost-effective method for effectively containing
the disease. According to the findings, the most cost-effective method for combating the spread of
soil-transmitted helminths is a combination of health education and sanitation. The soil-transmitted
helminth model was modified to form the second model for the co-infection with tuberculosis. The
qualitative analysis was made to determine the equilibrium points and the conditions for the disease
eradication. The impact of helminth infection on tuberculosis and vice-versa were discussed and it
was observed that helminth infection enhances tuberculosis in the community. Numerical simulation
for the model revealed that the interventions that include a combination of measures for controlling
helminth infection, vaccinating the babies with bacille Calmette-Guerin vaccine and the treatment of ´
individuals with active tuberculosis were effective in controlling the spread of the diseases. The last
model considered the interaction of the helminth parasites, mycobacterium tuberculosis pathogens,
and the immune competence within an individual host. Numerical simulations showed that primary
infection by either helminth parasite or Mtb bacteria is unsuccessful within the host when the basic
reproduction number is less than the unit