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1, 3-Dipolar cycloaddition reactions of selected 1,3-dipoles with 7-isopropylidenenorbornadiene and follow-up thermolytic cleavage: Acomputational study
(Elsevier Inc., 2019-08-08) Arhin, Grace; Adams, Anita Houston; Opoku, Ernest; Tia, Richard; Adei, Evans
The mechanism, regio-, stereo-, and enantio-selectivities of the 1,3-dipolar cycloaddition reactions of7-isopropylidenenorbornadiene (DENBD) with nitrones and azides to form pharmaceutically relevantisoxazolidine and triazole analogues have been studied computationally at the M06/6-31G(d), 6-31G(d,p), 6-311G(d,p), 6e311þþG(d,p) and M06-2X/6-31G(d) levels of theory. In the reactions of DENBDwith phenyl nitrones, the cycloaddition steps have low activation barriers, with the highest being 16 kcal/mol; and the Diels-Alder cycloreversion steps have generally high barriers, with the lowest being 20 kcal/mol, suggesting that the isolable products in these reactions are the bicyclic isoxazolidine cycloadductsand not the thermolytic products. This is in contrast to the reactions of DENBD with phenyl azide wherethe isolable products are predicted to be the thermolytic products since the Diels-Alder cycloreversionsteps had relatively lower activation barriers. Electron-donating substituents on the dipolarophile sub-strate favour attack of the nitrone on the least hindered side of the DENBD substrate while electron-withdrawing substituents on the dipolarophile substrate favour attack on the more hindered side ofthe DENBD, indicating that site-selectivity is affected by nature of substituents. Global reactivity indicescalculations are in good agreement with the activation barriers obtained. Analysis of the electrophilic(PþKÞand nucleophilic (P KÞParr functions at the reactive centres reveal that the cycloaddition occursbetween atoms with the largest Mulliken and NBO atomic spin densities which agrees well with theenergetic trends and the experimental product outcomes.
[3 + 2] Versus [2 + 2] addition: A density functional theory study on the mechanistic aspects of transition-metal-assisted formation of 1,2-dinitrosoalkanes
(Hindawi Publishing Corporation, 2016-11-21) Opoku, Ernest; Tia, Richard; Adei, Evans
The pathways for the transition metal-assisted formation of 1,2-dinitrosoalkane complexes of cobalt and its congeners, have beenstudied using DFT/M06 with the LACVP∗basis set. The activation barriers for the one-step [3 + 2] addition pathway for theformation of 1,2-dinitrosoalkanes, proposed by Bergman and Becker, are generally low compared to the activation barriers for the[2 + 2] addition to form an intermediate, which is the first of the two-step pathway proposed by Rapp ́e and Upton, which are veryhigh. The barriers of the rearrangement of the Rapp ́e intermediates to the final products by reductive elimination involving thesecond metal-nitrogen𝜋-bond are also very high. The reactions of the Co complexes have lower activation barriers than Rh andIr complexes. The barriers of the reactions involving olefins with electron-donating groups are generally lower compared to thereactions of the parent (unsubstituted) ethylene while the activation barriers for reactions of olefins with electron-withdrawinggroups are generally higher compared to the parent (unsubstituted) ethylene. The one-step [3 + 2] pathway remains the mostfavoured irrespective of the metal centre or the nature of the olefin. The mechanism of the reaction is therefore settled in favour ofthe [3 + 2] addition pathway.
3-Monochloropropandiol and glycidyl esters in heat-processed oil-based food products: Exposure and risk
(Applied Food Research, 2024-06) Yabani, Daniel Sitsofe; Ofosu, Isaac Williams; Ankar-Brewoo, Gloria Mathanda; Lutterodt, Herman Erick; 0000-0001-5442-6654; 0000-0002-9553-0834; 0000-0001-8574-3409; 0000-0001-7015-7597
Fatty acid esters of 3-monochloro-1,2-propanediol (3-MCPDE) and glycidol (GE) are potentially harmful heatinduced contaminants produced during food processing. In this study, 100 heat-treated oil-based food samples covering fried, smoked, grilled, and baked food groups were collected in Koforidua, Ghana and analysed for the two esters using gas chromatography-mass spectrometry. The dietary exposures were estimated by a probabilistic approach using Monte Carlo Simulation. Levels of 3-MCPDE and GE in the foods ranged from
A blockchain-based certificateless public key signature scheme for vehicle-to-infrastructure communication in VANETs
(Journal of Systems Architecture, 2019-10) Ali, Ikram; Gervais, Mwitende; Ahene, Emmanuel; Li, Fagen; 0000-0002-2893-4249; 0000-0002-0810-1055
Vehicular Ad Hoc Networks (VANETs) have been developing based on the state-of-art in wireless network communication technologies to improve traffic on roads. However, there are some threats to security and privacy due to the open wireless environment in VANETs and the high speed of vehicles. The uthentication of messages related to traffic which are exchanged with the vehicles and the Road-Side Unit (RSU) is considered one of the most VANETs necessary security requirements. In this context, several schemes have been designed to secure the traffic-related messages in VANETs. However, these schemes suffer from high computational costs in signatures’ verification. To minimize the computational cost of signature generation and verification, we propose an efficient Certificateless Public Key Signature (CL-PKS) scheme using bilinear pairing to provide conditional privacy-preserving authentication for Vehicle-To-Infrastructure (V2I) communication in VANETs. The CL-PKS scheme supports batch signature verification and aggregate signature verification functions to speed up verification process. In addition to this, we include blockchain to our CL-PKS scheme to implement revocation transparency of pseudo-identities efficiently before verifying the signatures. Furthermore, this scheme provides security proof and protection against different types of attacks. The proposed scheme incurs lower computational cost as compared to that incurred by existing schemes.
A comparative study of Ghanaian propolis extracts: Chemometric analysis of the chromatographic profile, antioxidant, and hypoglycemic potential and identification of active constituents
(Scientific African, 2023-11) Amankwaah, Frederick; Addotey, John Nii; Orman, Emmanuel; Adosraku, Reimmel; Amponsah, Isaac Kingsley; 0000-0002-4372-3992
Diabetes is a disease characterized by high post-prandial glucose levels, which lead to other complications such as peripheral end organ damage. The use of enzyme inhibitors in the management of Type-2 diabetes ensure the control of blood glucose levels via the control of carbohydrate metabolism. The use of standard agents such as acarbose is associated with unwanted side effects hence the need to investigate other sources of antihyperglycemic agents. Propolis, a natural substance from bees, possesses diverse biological activities including antioxidant, antimicrobial and antidiabetic properties. However, the phytochemical content of propolis and its extracts may vary depending on the geographical area, the solvent of extraction and type of bees. This study represents the first attempt to compare different extracts of propolis from the same source in sub-Saharan Africa. In this study, the effect of solvent and source of Ghanaian propolis on parameters such as the total phenolic and flavonoid contents, chromatographic profile, antioxidant and α-amylase inhibitory effects were investigated with the aim of identifying and characterizing the most promising extract, which could be of direct or indirect benefit in the management of Type-2 diabetes. Combinations of water, ethanol-water and ethanol extracts were prepared from propolis from three regions. Phytochemical screening was performed on the extracts after which the Folin Ciocalteu method and aluminum chloride colorimetric assay were used to estimate the total phenolic and flavonoid contents respectively. Antioxidant potential of extracts was estimated using DPPH and phosphomolybdenum assays. In-vitro α-amylase inhibition assay was used to investigate hypoglycemic effect of the extracts. Statistical tools such as ANOVA, principal component analysis, hierarchical cluster analysis employed to determine sources of variations within the data obtained, to classify the extracts based on activity and to predict the most effective extract. This extract was then subjected to UHPLC-Q-TOF MS/MS and GC–MS techniques to characterize the constituents. Chemometric analysis of the data obtained showed that the variations in the data could be explained by both propolis source and extraction solvent. Though ethanol extracts generally contained more constituents, the more notable activities were in the ethanol-water extracts. The ethanol-water extract of Bono East propolis (EWBE) was the most potent DPPH radical scavenger (IC50 of 149.37 ± 2.90 µg/mL as compared to 116.60 ± 0.93 µg/mL GAE standard). It was also one of the three extracts which were more potent than acarbose (369.89 µg/mL) in the α-amylase inhibition assay. The predominant constituents from the LC-MS dereplication of EWBE were caffeic acid and flavonoid derivatives whilst 5,5-dimethyl-1-oxa-5 silacyclononanone-9 was the most significant active constituent identified through the GC–MS analysis. The identified constituents are known to have strong antioxidant and antidiabetic properties. The effects of source and solvent of extraction on the biological and physicochemical properties of propolis in Ghana have been quantified using statistical tools. The combined biological effects of propolis suggest a possible role in their usage in the management of type-2-diabetes and its related complications. Ethanol-water extracts were the most promising with EWBE showing the strongest antihyperglycemic activity. Such extracts represent leads towards further research into toxicity and formulation in order to develop safe and useful products for the management of type-2 diabetes.
A Comparative Study of the Epidemiology of Treponemal Infection in the Volta and Oti Regions of Ghana: A Five-Year Multisite Parallel Population-Based Analysis vis-à-vis the Sentinel Survey
(Hindawi, 2021) Yao Lokpo Sylvester; Owusu-Dabo Ellis; Gameli Deku John; Ndudiri Orish Verner ....et al; Kye-Duodu Gideon; 0000-0003-4232-4292
Treponemal infections can be blood-borne with great public health consequences. This study is aimed at comparatively describing the five-year (2013-2017) regional epidemiology of treponemal infection using pregnant women in the sentinel survey and apparently healthy blood donors as a proxy for the general population at four sentinel sites in the Volta and Oti Regions of Ghana. We analyzed retrospective data from 17,744 prospective blood donors aged 18 to 58 years and 7,817 pregnant women in a sentinel survey with ages from 15 to 49 years at Hohoe, Ho, Tongu, and Krachi West sentinel sites in the Volta and Oti Regions. Laboratory data extracted include variables such as age, gender, date of blood donation, and Treponema pallidum chromatographic immunoassay results from the blood banks of the four study sites. The five-year treponemal infection rate among the pregnant women in the sentinel survey and prospective blood donors was 0.79% and 2.38%, respectively. Site-specific infection rate for population-based/sentinel survey was 4.6%/1.1%, 2.0%/0.5%, 1.3%/1.1, and 1.2%/0.3% for Hohoe, Ho, Krachi West, and Tongu, respectively. Significant gender disparity in Treponemal infection rate exists with a male preponderance. The regional infection rate in the sentinel survey is lower compared to the general population. Therefore, the use of pregnant women as a proxy for population estimates could underestimate the burden in the study jurisdiction.
A comprehensive cost-effectiveness analysis of control of maize streak virus disease with Holling’s Type II predation form and standard incidence
(Elsevier, 2022-06) Seidu, Baba; Asamoah, Joshua Kiddy K.; Wiah, Eric Neebo; Ackora-Prah, Joseph; 0000-0002-7066-246X
Maize streak virus disease, caused by the maize streak virus, has been identified as severe vector-borne disease in Africa. In most regions of the continent, the disease is generally uncontrolled, and in epidemic years, it contributes to massive yield losses and famine. We propose a Holling-type predation functional response to explore the disease transmission. We show the sensitivity indices of various embedded parameters in the basic reproduction number. To illustrate the dynamics of the disease of the maize–leafhopper interaction, we perform a numerical simulation, and the results are graphically displayed. Incorporating four control methods (infection control, predation control, removal of infected maize plants, and insecticide application) into the basic model yields an optimal control issue. We used the Incremental Cost-Effectiveness Ratio technique to evaluate the most cost-effective combination of the four controls. We notice that the most cost-effective strategy combines the simultaneous adoption of the four controls.
A critical review of carbonate reservoir wettability modification during low salinity waterflooding
(Petroleum, 2022-01-12) Sagbana, Perekaboere Ivy; Sarkodie, Kwame; Nkrumah, Wilberforce Aggrey
The nature of carbonate reservoirs promotes the adsorption of oil onto the rock surface hence making oil recovery a challenge even with the interventions of varied chemical EOR methods. Recently, low salinity water flooding has become of great interest since it is cost-effective and environmentally friendly. Although low salinity waterflooding has been highly investigated in sandstone reservoirs, it is not the same for carbonate reservoirs due to its complexities. Nonetheless, it has been proposed as a favourable technique to mobilise the trapped oil in carbonate reservoirs. Wettability alteration is regarded as the most accepted mechanism for low salinity flooding but has not been well understood making field scale applications doubtful. In this paper, we present a detailed review of the wettability alteration mechanisms in carbonate reservoirs during low salinity waterflooding. Parameters influencing wettability alteration in carbonates and the interactions that occur at the rock/brine/oil interface are also presented. The different methods utilised for wettability measurements during low salinity waterflooding are also reviewed including their drawbacks and advantages and recommendations. This will provide an improved understanding of the low salinity flooding application in carbonate reservoirs.
A cross‑sectional study on risk factors for infection with Parvovirus B19 and the association with anaemia in a febrile paediatric population inGhana
(Springer Nature, 2020) Herr Wiebke; Hogan Benedikt; Owusu-Dabo Ellis; Sarpong Nimako; Gyau Kennedy....et all; 0000-0003-4232-4292
Parvovirus B19 (B19V) occurs globally and can cause severe anaemia. The role of co-infections with Plasmodium falciparum (P. falciparum) has been controversially discussed. The study aimed to determine prevalence and severity of B19V infection, and the effect of co-infections on the risk for anaemia. Between November 2013 and April 2015 a total of 1186 hospital visits of children with fever admitted to a hospital in Ghana were recorded. Malaria, B19V and additional diagnostics for fever causes were performed. Recent B19V infection was defined as PCR and/or IgM positivity. Risk factors for a B19V infection and for anaemia were analysed. The prevalence of anaemia was compared between children with/without B19V infection, stratified for the presence of malaria. B19V IgM/PCR was positive in 6.4% (n = 76; 40 IgM + , 30 PCR + , 6 IgM + and PCR +). Among the B19V cases 60.5% had a simultaneous P. falciparum infection. B19V IgM positivity but not PCR positivity was associated with moderate-severe anaemia (OR = 2.6; 95%-CI: 1.3–5.3; P < 0.01 vs. OR = 0.9; 95%-CI: 0.4–1.8; P = 0.70). P. falciparum and IgM positive B19V infection were independent risk factors for anaemia with no evidence of effect modification. Our data show a significant association between B19V infection, defined as IgM but not PCR positivity, and moderate-severe anaemia. A multiplicative effect of B19V and P. falciparum infection was not found.
A formulation of Clausena anisata (Willd.) Hook. f. Ex Benth and Cassia sieberiana DC. alleviates the symptoms associated with osteoarthritis: a single-blind, randomised controlled trial of a traditional Ghanaian remedy
(Springer Open, 2019) Kwesi Prah, Thomford; Yorke, Joseph; Ama Kyeraa, Thomford; Amponsah, Isaac Kingsley; 0000-0002-5229-0340
Background: Clinical validation of herbal medicinal products is important for their widespread acceptance and application. In this single-blind, randomised controlled trial, a traditional Ghanaian herbal medicine formulation with Clausena anisata (Willd.) Hook. f. ex Benth and Cassia sieberiana DC. as ingredients was evaluated for its safety and effectiveness in the management of patients with osteoarthritis. The formulation for the purposes of this study was labelled with the code GC-500. Methods: A total of 57 participants were randomly assigned to receive either this herbal remedy, GC-500, or the control treatment of diclofenac. Subjects were then followed up for a period of 8 weeks using a modified Graded Chronic Pain Scale (GCPS) for their efficacy assessments. The control treatment comprised 13 subjects and the GC 500 group 44 subjects. Results: Upon completion of the study, 28 (63.63%) subjects in the GC-500 group attained the primary outcome, (GCPS of Grade 0) compared to 5 (38.46%) subjects in the control group. Improvement in disease indicators such as characteristic pain intensity, disability score and disability days was comparable between the GC-500 and diclofenac. Intensity of pain reduced after 8 weeks of treatment; disability score and disability days also declined indicating an improvement in the quality of life of subjects. GC-500 was also shown to be safe for human use. Conclusion: The herbal medicine formulation GC-500, provides a credible treatment option for managing the pain associated with osteoarthritis.
A fractal–fractional order model for exploring the dynamics of Monkeypox disease
(Elsevier, 2023-08) Wireko, Fredrick Asenso; Adu, Isaac Kwasi; Sebil, Charles; Asamoah, Joshua Kiddy K.; 0000-0002-7066-246X
This study explores the biological behaviour of the Monkeypox disease using a fractal–fractional operator. We discuss the existence and uniqueness of the solution of the model using the fixed-point concept. We further show that the Monkeypox fractal–fractional model is stable through the Hyers–Ulam and Hyers–Ulam Rassias stability criteria. The epidemiological threshold of the model is obtained. The numerical simulation for the proposed model is obtained using the Newton polynomial. For instance, the disease dies out at lower fractional values. We investigated the effects of some key parameters on the dynamics of the disease. The variation of the parameters shows that quarantine and isolation are effective approaches to managing, controlling, or eradicating the Monkeypox disease.
A fractional order age-specific smoke epidemic model
(Elsevier, 2023) Addai, Emmanuel; Asamoah, Joshua Kiddy K.; Zhang, Lingling; Essel, John Fiifi; 0000-0002-7066-246X
This paper presents a nonlinear fractional mathematical model for the smoke epidemic that includes two age groups. To solve the smoke epidemic, the Atangana-Baleanu-Caputo fractional derivative is used. The Banach and Krasnoselskii type fixed point theorem is used to determine existence and uniqueness. We explored model stability using the Hyers-Ulam form of stability. Using Lagrange interpolation, the behaviour of the smoke epidemic of the 2-age group model is generated. The numerical simulation shows that the model has po- tential for both groups, and that age-specific interventions can be used to reduce smoking rates in the general population.
A fractional order Ebola transmission model for dogs and humans
(Elsevier, 2024-05) Adu, Isaac K.; Wireko, Fredrick A.; Osman, Mojeeb Al-R. El-N.; Asamoah, Joshua Kiddy K.; 0000-0002-7066-246X
Ebola is a serious disease that affects people; in many cases, it results in death. Ebola outbreaks have also occurred in communities where residents keep pets, particularly dogs. Due to a lack of food, the dogs must hunt for food. Dogs eat the internal organs of wildlife that the locals have killed and eaten, as well as small dead animals that are found within the communities which may contain the Ebola virus. This study introduces a mathematical model based on the Caputo–Fabrizio derivative to describe the Ebola transmission dynamics between dogs and humans. The model’s existence and the uniqueness of its solution were investigated using fixedpoint theory. Furthermore, through the Sumudu transform criterion, we established that the Caputo–Fabrizio Ebola model is Picard stable. Some qualitative analysis was also carried out to investigate the Ebola propagation trend in the dog-to-human model. The proposed model is fitted to the reported Ebola incidence in Uganda between October 15, 2022, and November 2, 2022. The Ebola reproduction number obtained using the cumulative data was 2.65. It is noticed that as the fractional order reduces, the Ebola reproduction number also reduces. We derived a numerical scheme for our model using the two-step Lagrange interpolation. It has been discovered that the fractional orders significantly influence the model, indicating that natural occurrences could affect the dynamics of Ebola. It is observed that when the recovery rate is enhanced, such as through the hospitalisation of Ebola-infected individuals, the disease will reduce. Finally, as we ensure a reduction in the contact rate among the dog’s compartments, the disease does not spread adiabatically. Therefore, we urge that quarantine measures be put in place to control interactions among the dogs during the outbreak.
A fractionalcontrolmodeltostudyMonkeypox transportnetwork-relatedtransmission
(World Scientific, 2024-08) Zhang, Nan; Emmanuel, Addai; Mezue, MaryNwaife; Rashid, Saima; Akinnubi, Abiola; Abdul-Hamid, Zalia; Asamoah, Joshua Kiddy K.; 0000-0002-7066-246X
Effective disease control measures to manage the spread of Monkeypox (Mpox) virus are crucial, especially given the serious public health risks posed by the ongoing global epidemic in regions where the virus is both prevalent and not. This study introduces a precise model, based on the Caputo fractional derivative, which takes into account both human and non-human populations as well as public transportation, to delve into the transmission characteristics of Mpox outbreaks. By employing the fixed-point theorem, we have precisely determined the solutions regarding existence and uniqueness. We have analyzed the stability of various equilibrium states within the model to assess Mpox’s transmission capabilities. Additionally, through detailed numerical simulations, we have gauged the impact of critical model parameters that contribute to enhancing Mpox prevention and management strategies. The insights gained from our research significantly enrich epidemiological understanding and lay the foundation for improved disease containment approaches.
A gist on an obscure neoplasm in Ghana: gastrointestinal stromal tumours
(BMC Publisher, 2023) Yorke, Joseph; Brenu, Samuel Gyasi; Awoonor‑Williams, Ronald; Tabiri, Stephen; Seidu, Anwar Sadat; 0000-0002-5229-0340
Background Gastrointestinal Stromal Tumour is a rare but potentially curable tumour of the gastrointestinal tract accounting for up to 1% of all gastrointestinal tumours. The discovery of Imatinib mesylate, a novel tyrosine kinase inhibitor has improved the chances even for unresectable, recurrent, or metastatic diseases. Methods This study sought to document the clinical and pathological characteristics of GISTs from two tertiary hos‑ pitals in Ghana that have undergone immunohistochemistry confrmation between 2014 and 2021. Results The median age of the subjects was 50 years with most of them (28.0%) being above 61 years. There were more females than males (64.0% vs. 36.0%). Abdominal mass and abdominal pain made up the majority of the clinical presentations. The majority of the subjects had partial gastrectomy (32.0%) which was followed by wedge resec‑ tion (28.0%). Appendectomy and sleeve gastrectomy were the least performed procedures (8% each). Four of the 25 patients (16.0%) had resections of involved contiguous organs done with splenectomy being the most common procedure. The majority of GISTs were found in the stomach (68.0%) followed by the appendix (12.0%) and small bowel (12.0%). Gastrointestinal bleeding (55.8%) and abdominal pain (38.5%) were the most reported symptoms. Free resection margins were observed in 84.0% of the subjects and only 3/25 (12.0%) experienced tumour recurrence. Conclusion GIST is a potentially curable tumour that once was obscure but currently gaining popularity. Surgical resection ofers the hope of a cure for localized disease while targeted therapies is a viable option for recurrent, meta‑ static, or unresectable tumours.
A hierarchical intervention scheme based on epidemic severity in a community network
(Journal of Mathematical Biology, 2023-07) He, Runzi; Luo, Xiaofeng; Asamoah, Joshua Kiddy K.; Zhang, Yongxin; Li, Yihong; Jin, Zhen; Sun, Gui-Quan; 0000-0002-7066-246X
As there are no targeted medicines or vaccines for newly emerging infectious diseases,isolation among communities (villages, cities, or countries) is one of themost effectiveintervention measures. As such, the number of intercommunity edges (NIE) becomesone of themost important factor in isolating a place since it is closely related to normallife. Unfortunately, how NIE affects epidemic spread is still poorly understood. In this paper, we quantitatively analyzed the impact of NIE on infectious disease transmissionby establishing a four-dimensional SIR edge-based compartmental model with two communities. The basic reproduction number R0( l ) is explicitly obtained subjectto NIE l . Furthermore, according to R0(0) with zero NIE, epidemics spreadcould be classified into two cases. When R0(0) > 1 for the case 2, epidemics occurwith at least one of the reproduction numbers within communities greater than one,and otherwise when R0(0) < 1 for case 1, both reproduction numbers within communitiesare less than one. Remarkably, in case 1, whether epidemics break out stronglydepends on intercommunity edges. Then, the outbreak threshold in regard to NIEis also explicitly obtained, below which epidemics vanish, and otherwise break out.The above two cases form a severity-based hierarchical intervention scheme for epidemics.It is then applied to the SARS outbreak in Singapore, verifying the validityof our scheme. In addition, the final size of the system is gained by demonstrating theexistence of positive equilibrium in a four-dimensional coupled system. Thoretical results are also validated through numerical simulation in networks with the Poisson and Power law distributions, respectively. Our results provide a new insight into controlling epidemics.
A hybrid forecasting technique for infection and death from the mpox virus.
(Digital Health, 2023) Iftikhar, Hasnain; Daniyal, Muhammad; Quresh, Moiz; Tawaiah, Kassim; Ansah, Richard Kwame; Afriyie, Jonathan Kwaku; 0000-0001-6997-7969
Objectives: The rising of new cases and death counts from the mpox virus (MPV) is alarming. In order to mitigate the impact of the MPV it is essential to have information of the virus’s future position using more precise time series and stochastic models. In this present study, a hybrid forecasting system has been developed for new cases and death counts for MPV infection using the world daily cumulative confirmed and death series. Methods: The original cumulative series was decomposed into new two subseries, such as a trend component and a stochastic series using the Hodrick–Prescott filter. To assess the efficacy of the proposed models, a comparative analysis with several widely recognized benchmark models, including auto-regressive (AR) model, auto-regressive moving average (ARMA) model, non-parametric auto-regressive (NPAR) model and artificial neural network (ANN), was performed. Results: The introduction of two novel hybrid models, HPF1 1 and HPF4 3, which demonstrated superior performance compared to all other models, as evidenced by their remarkable results in key performance indicators such as root mean square error (RMSE), mean absolute error (MAE) and mean absolute percentage error (MAPE), is a significant advancement in disease prediction. Conclusion: The new models developed can be implemented in forecasting other diseases in the future. To address the current situation effectively, governments and stakeholders must implement significant changes to ensure strict adherence to standard operating procedures (SOPs) by the public. Given the anticipated continuation of increasing trends in the coming days, these measures are essential for mitigating the impact of the outbreak.
A Mathematical Analysis of the Impact of Immature Mosquitoes on the Transmission Dynamics of Malaria
(Wiley, 2024-09) Sualey, Nantogmah Abdulai; Akuka, Philip N. A.; Seidu, Baba; Asamoah, Joshua Kiddy K.; 0000-0002-7066-246X
This study delves into the often-overlooked impact of immature mosquitoes on the dynamics of malaria transmission. By employing a mathematical model, we explore how these aquatic stages of the vector shape the spread of the disease. Our analytical findings are corroborated through numerical simulations conducted using the Runge–Kutta fourth-order method in MATLAB. Our research highlights a critical factor in malaria epidemiology: the basic reproduction number R0 . We demonstrate that when R0 is below unity R0 < 1 , the disease-free equilibrium exhibits local asymptotic stability. Conversely, when R0 surpasses unity R0 > 1 , the disease-free equilibrium becomes unstable, potentially resulting in sustained malaria transmission. Furthermore, our analysis covers equilibrium points, stability assessments, bifurcation phenomena, and sensitivity analyses. These insights shed light on essential aspects of malaria control strategies, offering valuable guidance for effective intervention measures.
A mathematical model of corruption dynamics endowed with fractal–fractional derivative
(Elsevier, 2023-08) Nwajeri, Ugochukwu Kizito; Asamoah, Joshua Kiddy K.; Ugochukwu, Ndubuisi Rich; Omamea, Andrew; Jin, Zhen; 0000-0002-7066-246X
Numerous organisations across the globe have significant challenges about corruption, characterised by a systematic, endemic, and pervasive nature that permeates various societal establishments. Hence, we propose the fractional order model of corruption, which encompasses the involvement of corrupt individuals across various stages of education and employment. Specifically, we examine the presence of corruption among children in elementary schools, youths in tertiary institutions, adults in civil services, adults in government and public offices, and individuals who have renounced their involvement in corrupt practices. The basic reproduction number of the system was determined by utilising the next-generation matrix. The strength number was obtained by calculating the second derivative of the corruption-related compartments. The examined model solution’s existence, uniqueness, and stability were established using the Krasnoselski fixed point theorem, the Banach contraction principle, and the Ulam–Hyers theorem, respectively. Based on the numerous figures presented, our simulations indicate a positive correlation between the decline in fractal– fractional order and the increase in the number of individuals susceptible to corruption. This phenomenon results in an increase in the prevalence of corruption among designated sectors of the general population. The persistence of corruption in society is a significant challenge to its eradication, as individuals who see personal gains from engaging in corrupt practices tend to exhibit a recurring inclination towards such behaviour. Nevertheless, it is recommended that to mitigate corruption within various corruption-prone subcategories, there is a need to enhance the level of consciousness and promotion of anti-corruption measures throughout all societal establishments.
A MATHEMATICAL MODEL OF COVID-19 TRANSMISSION DYNAMICS WITH EFFECTS OF AWARENESS AND VACCINATION PROGRAM
(Journal of Ghana Science Association, 2023-10) Agbata, B.C.; Shior, M.M.; Obeng-Denteh, W.; Omotehinwa, T.O.; Paul, R.V.; Kwabi P. A.; Asante-Mensa, F
This study introduces a deterministic mathematical model for understanding the transmission dynamics of COVID-19, con sidering the influence of vaccination and awareness program, which target susceptible individuals. The model is based on a system of differential equations, resulting in an SVEIR model. Through qualitative analysis, various aspects of the model, such as disease-free equilibrium, endemic equilibrium, basic reproduction number, and local and global stability, were thoroughly explored. The disease-free equilibrium is proven to be both locally and globally stable when R0 < 1, while it ∼becomes unstable when R0 > 1. Simulation results demonstrate that the combination of vaccination and awareness programs emerges as the most effective approach to mitigate the spread of COVID-19 within the population.

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