University of Uyo
  • Uyo, AKWA IBOM STATE, Nigeria
Recent publications
In recent years, there have been emerging studies on developing different techniques to improve the properties of pyrolysis bio-oil. One of such techniques is the co-pyrolysis of biomass with hydrogen-rich feedstock of higher fuel qualities. Co-pyrolysis aims to decrease the water and oxygen contents, increase the calorific and heating values, and eliminate the corrosion and instability problems associated with their direct use in boilers and turbines for heat and power generation and as a transport fuel. Lignocellulosic and macroalgae biomass feedstocks are complementary based on their different compositions, and this combination has been employed in co-pyrolysis techniques. In this review, the biomass feedstock characteristics and their effects on thermal conversion into bio-oil were discussed. Due to the heterogeneous nature of the two biomass feedstocks, investigations of their co-pyrolysis behaviour and their reaction mechanisms in both catalytic and non-catalytic reactions were explored. The synergistic effect which is the key reason behind the improvement in the yield and quality of bio-oil obtained from the co-pyrolysis of these biomass feedstocks was also examined. The resulting bio-oils from the co-pyrolysis were comprehensively analyzed and are characterized by improved properties than the pyrolysis of lignocellulosic or macroalgae biomass alone. However, due to thermal degradation, the existence of high oxygenated compounds in this pyrolysis bio-oil is a challenge that needs to be overcome. Catalytic co-pyrolysis could be implemented for additional upgrading of the pyrolysis bio-oil as liquid fuel for several purposes. Finally, the main bottlenecks, key solutions and future directions for the study were provided.
Background Bacteremia constitutes a significant public health challenge and represents a vital cause of morbidity and mortality in HIV-infected patients, and fluoroquinolones are commonly prescribed antibiotics due to their range of activities and pharmacokinetic profiles. This study the evaluated antibacterial activities and time-kill kinetics of fluoroquinolone antibiotics: Ofloxacin (OFL), Ciprofloxacin (CIP) and Levofloxacin (LEV) against the etiology of bacteremia of genera Staphylococcus, Streptococcus, Acinetobacter, Pseudomonas, Klebsiella, Haemophilus, Enterobacter , and Salmonella using disc diffusion, micro-broth dilution and plate count techniques. Results The lowest mean growth inhibition zones (mm ± SD) of OFL, LEV, and CIP against the isolates were 10.5 ± 0.0, 10.1 ± 0.1 and 9.6 ± 0.3, respectively. The MIC values of OFL, LEV and CIP on isolates ranged from 6.25 to > 50 µg/mL, MBC ranged from 12.5 to > 50 µg/mL, while MBC/MIC ratios were ≤ 2. The time-kill assay revealed that logarithmic reductions in viable cell counts (Log 10 CFU/mL) of bacteria exposed to OFL, LEV and CIP ranged from 0.17 to 2.14 for P. aeruginosa ; 0.13 to 1.31 for H. influenzae ; 0.04 to 2.23 for Acinetobacter spp; and 0.08 to 2.08 for K. pneumoniae. LEV and OFL (1 × MIC concentration) achieved bactericidal effects on S. typhi ST07 and E. aerogenes EA01 at 30 h post-inoculation, respectively, while ≥ 99.9% reduction in the number of viable K. pneumoniae cells exposed to CIP was achieved at 24 h post-inoculation. Conclusion The fluoroquinolones demonstrated higher inhibitory activities at higher concentrations against the etiology of bacteremia in HIV-infected patients, signifying a concentration-dependent inhibition of bacterial growth. The MIC-based time-kill curve analyses showed that LEV achieved 3 Log 10 -fold reduction (≥ 99.9% reduction) in CFU/mL of most etiology of bacteremia faster compared with the other two fluoroquinolones.
Mammea africana Sabine (Guttiferae), a medicinal plant used traditionally in the treatment of diseases including diabetes was evaluated for effect on alpha-amylase and alpha-glucosidase enzymes in vivo. The stembark extract (30, 60 and 90 mg/kg) of M. africana were investigated in vivo for inhibitory effect on alpha-amylase and alpha-glucosidase enzymes using starch, sucrose and maltose as substrates. Acarbose was used as reference drug. The stembark extract caused significant (p<0.05) reduction in blood glucose levels of treated rats with the various substrates used. The results suggest that the stembark extract of M. africana have the potentials to inhibit alpha-amylase and alpha-glucosidase in rats.
Most available artificial intelligence models for bubble-point pressure (Pb) and oil formation volume factor (Bob) are multiple-input single-output models that are not reproducible or with complex topology. In this study, a multiple-input multiple-output genetically optimized neural network to predict oil Pb and Bob was developed using solution gas–oil ratio, API-oil gravity, gas gravity and reservoir temperature from 781 published datasets. The overall performance of the developed neural network resulted in a correlation coefficient (R) of 0.99918 and a mean square error (MSE) of 5.9941 × 10–4. The developed Pb and Bob models predictions resulted in a coefficient of determination (R2) of 0.9985 and R-value of 0.99423 for Pb, then R2 of 0.9842 and R-value of 0.99207 for Bob. Also, the Pb model had MSE of 2.0 × 10–4, root mean square error (RMSE) of 4.45 × 10–3 and average absolute percent relative error (AAPRE) of 0.4447, while Bob had 1.0 × 10–4, 3.9 × 10–3 and 0.0391 for MSE, RMSE and AAPRE, respectively. Furthermore, the generalization capacity of the developed models with new datasets resulted in R2, R, MSE, RMSE and AAPRE of 0.9613, 0.98046, 0.03713, 0.1927 and 19.2698, respectively, for Pb, as the Bob model had R2 of 0.9499, R of 0.97463, MSE of 0.0218, RMSE of 0.14763 and AAPRE of 8.20211. Again, the developed Pb and Bob models' generality performance showed that they outperformed some published correlations: Standing [1], Glaso [2], Al-Marhoun [3], Dokla and Osman [4], Almehaideb [5], Al-Shammasi [6], etc. Thus, these developed explicit Pb and Bob models for oil reservoir PVT prediction can be applied.
Within the framework of non-relativistic quantum mechanics, the bound state approximate solution of the SE is solved for the coshine Yukawa potential (CYP) using the Nikiforov–Uvarov (NU) method. By employing the Greene-Aldrich-type approximation scheme, we have obtained the explicit energy-eigenvalues and corresponding normalized eigen-functions in closed form for the newly proposed CYP for hydrogen-related diatomic molecules such as hydrogen dimer ( H 2 ), lithium hydride ( LiH ), scandium hydride ( ScH ) and hydrogen chloride ( HCl ). The thermodynamic properties are also evaluated including the vibrational partition function, vibrational mean energy, vibrational mean free energy, vibrational entropy and vibrational specific heat capacity. Presented also are some numerical results which show an indication of similar correlation of energies, owing to their ion-ion coupling with regards to similar atomic radii existing among the diatomic molecules.
Poor waste disposal practices impinge on water quality. An assessment of the effect of domestic solid wastes disposal practices on microbial quality of drinking water sources was conducted in some rural communities of Akwa Ibom State, Nigeria. An ecological study design was adopted using quantitative methods and a multi-stage sampling technique for random selection of LGAs, communities, and households for the administration of questionnaires to 120 respondents within four communities. Microbiological analysis of water samples from various sources was also conducted. A total of 26 (43.3%) and 16 (26.7%) households in the coastal and upland areas respectively had waste disposal facilities, the remaining percentage dumped waste into rivers and nearby bushes. The majority of the coastal community dwellers defecate directly into water bodies or swamps due to a lack of faeces disposal facilities whereas all respondents in the upland areas had faeces disposal facilities though some were unimproved. The result of the microbial analysis showed that the coastal areas had a mean heterotrophic bacterial, coliform, and fungal count of 1.45(± 0.44) × 105 cfu/ml, 0.90(± 0.27) × 105 cfu/ml, and 1.75(± 0.50) × 105 cfu/ml while the upland areas had 1.34(± 0.55) × 105 cfu/ml, 0.65(± 0.36) × 105 cfu/ml, and 1.88(± 0.58) × 105 cfu/ml. There was no significant difference (P < 0.05) in microbial water quality between the coastal and upland areas besides the self-reported health problems. A moderate positive correlation was found between solid waste disposal practices and total bacterial count (r = 0.418**), and total coliform (r = 0.397**), P < 0.01. Most of the microorganisms isolated from drinking water in both settings were of public health importance. The result obtained from this study indicates very poor water quality in both settings. This implicates the poor solid waste disposal practices predominant in these communities and calls for immediate measures to secure the health of the rural community dwellers.
In this article, we develop a faster iteration method, called the A∗∗ iteration method, for approximating the fixed points of almost contraction mappings and generalized α nonexpansive mappings. We establish some weak and strong convergence results of the A∗∗ iteration method for fixed points of generalized α-nonexpansive mappings in uniformly convex Banach spaces. We provide a numerical example to illustrate the efficiency of our new iteration method. The weak w^2-stability result of the new iteration method is also studied. As an application of our main results, we approximate the solution of a fractional Volterra–Fredholm integro-differential equation. Our results improve and generalize several well-known results in the current literature.
Background Exposure to lead produces a variety of adverse health effects. This study evaluated the protective effect of Carica papaya leaves(CPL) and seed (CPS) against lead bioaccumulation in albino rats. Methods Thirty male rats weighing 174-196g were assigned to six groups of five animals receiving various treatments: group 1- control; 2-50mg/kg body weight (BW) lead nitrate (PbNO3); 3- 500 mg/kg BW CPL extract; 4- 500 mg/kg BW CPS extract; 5- 50mg/kg BW PbNO3 + 500mg/kg BW CPL; and 6- 50mg/kg BW PbNO3 + 500mg/kg CPS orally for 31 days. Results The study revealed a significant reduction (P < 0.05) in lead bioaccumulation in liver and kidney of the lead treated groups complemented with CPL (0.72 ± 0.28mg/l and 0.85 ± 0.17mg/l) and CPS (0.29 ± 0.10mg/l and 0.36 ± 0.10mg/l), compared to the liver and kidney of animals in the group treated with lead alone (11.32 ± 3.20mg/l and 14.62 ± 3.78mg/l).The reduction in bioaccumulation was however non-significantly higher (P > 0.05) in the group complemented with CPS than CPL. Conclusion This finding suggests that CPL and CPS have the potential of reducing lead bioaccumulation and could be harnessed by pharmaceutical industries for this potential.
A speaker identification framework that combines both high- and low-level features, for state-of-the-art variability analysis and classification is proposed in this paper. The proposed framework introduces a workable solution that targets robust speaker variability classification using speech samples recorded in suboptimal conditions. A translated Ibibio (New Benue-Congo, Nigeria) version of “The Tiger and the Mouse”—a prosodically balanced corpus that demonstrates the prosody of read-aloud English was used in this study with speech samples obtained from 50 participants (25 males and 25 females). Identity-vectors (i-vectors) or low dimensional signal patterns were extracted and used as baselines for investigating speakers’ variability patterns across various classifiers (Decision Tree: DT, Support Vector Machine: SVM, k-Nearest Neighbour: k-NN, and Deep Neural Network: DNN) and kernels. Treatment of the baselines with high level features (speech duration, F0, intensity) was also experimented for word, syllable, and phoneme units. Results obtained revealed that DTs and some variants of SVM gave high classification accuracies (above 70%). Hence, the hypothesis of universal Gaussianity appears inexact, as the linear predictor that is optimal in the mean square error sense may not hold for Ibibio. Further treatments of the baselines with Linear Discriminant Analysis (LDA) and Cosine Distant Scoring (CDS) yielded very poor classification results, except for the k-NN and Gaussian SVM classifiers which performed well for the LDA treated baselines.
Ultisols are peculiar soils generally known for their poor nutrient status. When contaminated, remediation of ultisols present the additional challenge of nutrient and ecological restoration. In this study, we report the distribution of total petroleum hydrocarbons (TPHs) in a simulated crude oil‐contaminated ultisol amended with biochar (BC)/humus sediment (HS) slurry. We also investigated the microbial abundance, diversity, and enzyme expression in the treatment medium that gave the optimum remediation results. We recorded lowest TPH levels in remediant amendments with BC produced at 700°C. Majority of the OTUs (27.96%) found in the remediated ultisol belonged to Firmicutes (27.96%), Proteobacteria (25.88%), and Gemmatimonadetes (23.32%) while enzymes (AlkM, alkB, AlmA, PRM, cP450, MMO/AMO subunits A, B, and C, and Genes ssuD, ssuC, dszC, dszA, and dszB) encountered in this study were expressed mainly by bacteria belonging to the order Actinomycetales and Bulkhoderiales.
Objective: Vaccine development, distribution, and immunization of large populations have been identified as vital mitigation strategies for curbing the spread of COVID-19. However, vaccine hesitancy is a major barrier to this. The knowledge and perception of COVID-19 vaccines can improve vaccine acceptance. The purpose of this study was to assess medical students’ knowledge, attitude, and perception of COVID-19 vaccines. Methods: This study was a cross-sectional web-based survey conducted among undergraduate students from the faculties of Basic medical sciences and Clinical sciences, University of Uyo, Akwa Ibom State, Nigeria. The students’ knowledge was ranked as excellent (>70%), good (50–69%) and poor (<50%) while perception was categorized into positive (>50%), and negative (<50%). The difference in knowledge based on demographics was analyzed using the Independent sample t-test. The association between demographics, and students’ perception was carried out using the Chi-square and Fisher’s Exact tests. Analyses were conducted using SPSS software version 25. Results: A total of 233 students consented to participate in the study out of which 51.1% were female. Forty-eight students (20.6%) had good knowledge while 41.2% of the participants accepted to take the COVID-19 vaccine. Positive perception was reported among 51.1% (119) of the students. Conclusion: There was poor knowledge and positive perception among majority of the students. Educational intervention in form of training should be done to improve medical students’ knowledge and perception toward COVID-19 vaccination.
Mycotoxin contamination of foods from mycotoxigenic fungi such as Aspergillus, Alternaria, Fusarium and Penicillium spp. is a significant threat to food safety and quality. Aflatoxins, ochratoxins, fumonisins, deoxynivalenol, zearalenone, trichothecenes and patulin have been demonstrated to show immune toxicity, carcinogenicity, nephrotoxicity, hepatotoxicity, neurotoxicity and teratogenicity activities in humans and animals. Implementation of the prerequisite programs like the HACCP-based procedures can reduce mycotoxin contamination, while conventional chemical, biological and physical methods can be employed for detoxification after contamination. But the increasing fungal resistance and challenges associated with the conventional systems necessitate the development of innovative strategies for rapid elimination with short processing time and negligible impact on quality. This review evaluated recent innovative strategies of cold atmospheric plasma (CAP), polyphenols and flavonoids, magnetic materials and nanoparticles and natural essential oils (NEOs) for controlling mycotoxin in foods. Although the available studies indicated the promising potential of these strategies, complete decontamination was not achieved. The mechanisms for the reduced bioactivity of mycotoxins included the disruption of fungal cell membrane and structural degradation of complex biochemical molecules by the oxidative effects of reactive species, inhibition of enzymes responsible for breakdown of carbohydrates and adsorption and binding of functional groups of mycotoxins in food substrate. Integrated management systems of combining multiple strategies can be explored for achieving higher efficiency and better adaptability to different food matrices. Additional studies on the toxicity of the food matrices, degraded products and industrial up-scaling are necessary for ensuring widespread adoption and cost-effective commercialisation for sustainable food processing.
A shifted Morse potential model is modified to fit the study of the vibrational energies of some molecules. Using a traditional technique/methodology, the vibrational energy and the un-normalized radial wave functions were calculated for the modified shifted Morse potential model. The condition that fits the modified potential for molecular description were deduced together with the expression for the screening parameter. The vibrational energies of SiC, NbO, CP, PH, SiF, NH and Cs2 molecules were computed by inserting their respective spectroscopic constants into the calculated energy equation. It was shown that the calculated results for all the molecules agreement perfectly with the experimental RKR values. The present potential performs better than Improved Morse and Morse potentials for cesium dimer. Finally, the real Morse potential model was obtained as a special case of the modified shifted potential.
This study investigated the causal linkage between information and communication technologies (ICT) and sustainable development (environmental—CO2, economic—RGDP, and social—HDI) in the ECOWAS subregion categorized into low‐income and lower‐middle‐income countries for the period 1995–2020. Cointegrating regression and causality methods were employed to estimate the dynamic linkage among variables in panel fully modified ordinary least squares (PFMOLS) and Dumitrescu–Hurlin causality models. The results of the study support the environmental Kuznets curve (EKC) hypothesis for low‐income countries while it rejects EKC for lower‐middle‐income countries. The study recommends policy formulations targeted at incentivizing the use of environmentally friendly technologies that minimizes positive impact on the environment and enhance sustainable development.
There is a growing interest in using mathematical models to understand crime dynamics, crime prevention, and detection. The past decade has experienced a relative reduction in conventional crimes, but this has been replaced by significant increases in cybercrime. We use a system of nonlinear differential equations to explore the impact of criminal location in relation to cyber networks on the amount of cybercrime. Using steady-state analysis and extensive numerical simulations, we find that the location of criminals relative to the network does not impact the system qualitatively although there are quantitative differences. Cyber networks that are more clustered are likely to experience greater levels of cybercrime but there is also a saturation effect that limits the level of victimisation as the number of criminals attempting to undertake crimes on a given network increases.
In this present study, we model Eckart-Hellmann Potential (EHP) to interact in a quark-antiquark system. The solutions of the Schrödinger equation are obtained with EHP using the Nikiforov-Uvarov method. The energy equation and normalized wave function were obtained. The masses of the heavy mesons such as charmonium (cc-) and bottomonium (bb-) for different quantum numbers were predicted using the energy equation. Also, the partition function was calculated from the energy equation, thereafter other thermal properties such as mean energy, free energy, entropy, and specific heat capacity were obtained. The results obtained showed an improvement when compared with the work of other researchers and excellently agreed with experimental data.
Several tropical regions of the world, including West Africa are strong climatic hotspots where increase in extreme climatic events (e.g., droughts) impact water resources and hydro-ecological systems. Even though the West African Sahel has been widely studied, reports on the rainfall climatology of coastal West Africa are considerably limited. Assessing the evolutionary changes in rainfall in this region is crucial to improving the understanding on the impacts of global climate systems on rainfall variability. The main aim of this study is to assess the impact of climate change on the characteristics (mean annual, wettest month, driest month, and mean monthly) of coastal West African rainfall using General Circulation Model and two representative concentration pathways (RCP 4.5 and RCP 8.5 emission scenarios). Climate teleconnection induced rainfall is quantified using the partial least squares regression, and the dominant patterns of rainfall variability in the region are also assessed. The results indicate that areas along the coast with leading modes of rainfall variability and characterized by bimodal rainfall patterns are projected to receive highest rainfall in the mid (2041–2070) and end (2071–2100) of the century. However, inland areas are expected to receive low rainfall under the influence of both emission scenarios. An exception to this is the inland middle belt in Nigeria, which is projected to receive more rainfall than its surrounding areas. These results imply an intensification of the water cycle along the coastal region that could lead to increasing propensity of flood and drought events. Finally, Togo, Côte d’Ivoire, southern Ghana, Benin are hotspots in coastal West Africa where climate teleconnection patterns induce changes in rainfall.
A strain of Stenotrophomonas acidaminiphila, isolated from fermenting bean-processing wastewater, produced alkaline protease in pretreated cassava waste-stream, but with low yield. Strain improvement by alternate combinatorial random mutagenesis and bioprocess optimization using comparative statistical and neural network methods enhanced yield by 17.8-fold in mutant kGy-04-UV-25. Kinetics of production by selected mutant modeled by logistic and modified Gompertz functions revealed higher specific growth rate in mutant than in the parent strain, likewise volumetric and specific productivities. Purification by PEG/Na⁺ citrate aqueous two-phase system recovered 73.87% yield and 52.55-fold of protease. Its activity was stable at 5-35% NaCl, 45-75°C, and was significantly enhanced by 1-15 mM sodium dodecyl sulfate (SDS). The protease was inhibited by low concentrations of phenyl-methyl-sulfonyl fluoride but was activated by 1-5 mM Mn²⁺ suggesting a manganese-dependent serine-protease. The 45.7 kDa thermo-halo-stable alkaline protease demonstrated keratinolytic and blood-stain removal potentials showing prospects in textile and detergent industries, respectively.
As the major consumer of resources and energy, the construction industry has been at the heart of the debate on sustainable development. The Sustainable Development Goals (SDGs) provide the overarching guidance for the construction industry to promote sustainable development from environmental, social, and economic dimensions. Moreover, sustainable consumption and production (SCP) are highlighted in the SDG 12, while Sustainable Procurement (SP) focuses on promoting sustainable development through procurement processes and decisions. However, little has been written about how the construction industry could turn the challenges of SP into opportunities that promotes procurement practices in accordance with national policies and priorities. This study examines the drivers and challenges on the adoption of sustainable procurement in construction and how it impacts the achievement of SDG 12. The quantitative approach using questionnaires identified the drivers and barriers to SP implementation in construction and the SP practices contributing to the realisation of SDG 12 (Responsible consumption and production). The results confirmed that the construction industry should play a significant role in achieving the SDGs and show that construction SP practices contribute to the realisation of 9 of the SDG 12 targets. The results also suggested that governments should play a more active role in partnership with industry stakeholders and that the social and economic dimensions of sustainability deserve more attention. The value of this study is to provide construction industry stakeholder an insight into the drivers and challenges of SP and how to turn SP challenges into opportunities by adopting initiatives that consider the environmental, social, and economic impact of all procurement decisions. It also highlights the important role of the construction industry towards the realisation of the SDGs, particularly the significance of SP practices in the construction industry to the achievement of SDG 12.
The link between increasing global population, food demand, industrialization, and agricultural waste is strong. Decomposing by-products from food cycles can introduce harmful toxic heavy metals, active degrading microbes, and enzymes to the environment. Additionally, high greenhouse gas emissions from the decomposing wastes contribute to global change and a high carbon economy. The bioeconomy and circular economy of biosurfactant production utilize these cheap feedstocks and promote waste to valuable product initiatives. Waste reduction, reuse, and recycling in an integrating green economy bioprocess ensure the sustainability of novel, cost-effective, safe, and renewable health-grade biosurfactants. This work reviews green economy concepts integration with sustainable biosurfactant production and its application in health-related industries. Benefits from recent advances in the production, characterization, and health-wise classification of biosurfactants were further discussed, including its limitations, techno-economic assessment, market evaluations, possible roadblocks, and future directions.
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1,042 members
Edet Akpanyung
  • Department of Biochemistry
Monday Akpanabiatu
  • Department of Biochemistry
Dennis Edem
  • Department of Soil Science & land Resources management
Paul  A. Nwafor
  • Department of Pharmacology & Toxicology
Head of institution
Professor Nyaudoh Ndaeyo( Vice chancellor)