207 research outputs found

    Formulation of a mathematical model for transmission and control of Zika virus fever dynamics

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    We formulated a mathematical model for the transmission and control of zika virus fever dynamics, incorporating controls; and mosquito bite, sexual contact, vertical transmission blood transfusion as medium of transmissions. Based on our previous findings that the model is mathematically well posed for analysis, the state variablesat the endemic state are expressed in terms of parameters and forces of infection, substitution and simplifying led to a polynomial. Invoking Descartes sign rule of polynomial confirmed the existence of a unique endemic equilibrium point of the model if and only if the effective reproduction number is greater than one (Re > 1).Keywords: Zika virus fever; Control; Medium of transmission; Unique endemic equilibrium poin

    EFFECTS OF ANIMATION AND CONCEPT MAP VISUALIZATION ELEMENTS ON ACHIEVEMENT, RETENTION AND INTEREST IN GEOGRAPHY AMONG SECONDARY SCHOOL STUDENTS IN WUSE, ABUJA

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    This study investigated the effects of animation and concept map visualization elements on achievement, retention, and interest in geography among Secondary School Students in Wuse, Abuja, Nigeria. It also examined the influence of gender on students’ achievement, retention, and interest. The research used a pre‐test post‐test experimental and control group design. 120 secondary school students were drawn from three secondary schools within the Abuja metropolis. A stratified random sampling technique was used to select 120 students (53 males and 67 females). Nine research questions and hypotheses guided the study, Weather Interest Questionnaire and Weather Achievement Test (WAT) were used as instruments for data collection while animation and concept map visualization was used as the treatment instruments. The treatment instruments, questionnaire, and achievement test were validated by educational technology experts and Geography Education experts respectively. Pilot tests were carried out and a Reliability coefficient of 0.87 was obtained using Pearson Product Moment Correlation (PPMC) for WAT and 0.75 was obtained using Cronbach alpha for the questionnaire. WAT was administered to students as pre‐test and post‐test. The students’ pretest and post‐test scores and the questionnaire were analyzed using ANCOVA (F = 8.839, p = 0.004) and t‐test statistics (t (52) = 0.179, p = 0.947) respectively. The results indicated that the students taught weather using animation and concept map visualization performed significantly better in the posttest and retention test than their counterparts taught weather using the lecture method respectively. However, there was no significant difference reported in the post‐test achievement scores of male and female students taught weather using animation and concept map visualization respectively (t= 1.916, p = 0.059). These findings indicated that weather concepts in geography could be taught and learned meaningfully through the use of animation and concept map visualization. Based on these findings, it was recommended among others that Government and school administrators should make provision of infrastructure that support the learners through the use of technology, this will encourage and enable learners to communicate with each other and give them the opportunity to share and access different teaching materials that can aid their learning

    Stability Analysis of a Mathematical Model for Onchocerciaisis Disease Dynamics

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    In this work, we propose a Deterministic Mathematical Model that Combines Infectious but not Blind and Infectious Blind Compartments for Onchocerciasis Transmission and Control. Onchocerciasis is usually the term used to describe river blindness, it is a disease that causes blindness, and the second largest cause of blindness after trachoma. It mainly affects the eyes and the skin. The equilibrium states of the model are obtained. The disease free equilibrium state is analysed for stability; the condition for its stability is obtained as an inequality constraint on the parameters. Results shows that although, a 60% treatment coverage rate of infected and infectious blind individuals only is better than 80% treatment coverage rate of infected but not blind individuals only. Also, all the four control strategies reduce the effective reproduction number below unity. A 40% coverage rate of fumigation and treatment of infectious but not blind is better than a 40%coverage rate of fumigation only. It further reveals that a 30% coverage rate of fumigation and treatment of infectious blind is better than 80%coverage rate of fumigation only or fumigation and treatment of infected but not blind only. We are able to show that disease free equilibrium and endemic equilibrium exists and are both locally and globally stable, and we computed the Rc of the model and showed that it is a parameter to test for stability, we also use the Jacobi stability technique to show that disease free equilibrium and endemic equilibrium are both locally and globally stable. The sensitivity analysis results shows that the most sensitive parameter is ρ while the least sensitive is  ΌvKeywords: Onchocerciasis, Mathematical model, Equilibrium state, Deterministic, Effective reproductive number, Stability

    Global stability analysis of the disease-free equilibrium state of a mathematical model of trypanosomiasis

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    The global stability analysis represents a compound failure, mechanism which provides lower calculated factors of safety. In this research, the global stability analysis was used to propose a mathematically model of the transmission dynamics and control of Trypanosomiasis, known as African sleeping sickness. We obtained the Disease-free equilibrium state and present graphical profile of some of the compartments.Keywords: Equilibrium state, trypanosome, sleeping sickness, stabilit

    Optimization of protocols for DNA extraction and RAPD analysis in West African fonio (Digitaria exilis and Digitaria iburua ) germplasm characterization

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    Fonio is an important indigenous grain crop of West Africa, but the extent of genetic diversity in fonio, its origin and phylogeny are not well understood. DNA markers allow precise characterization of plant germplasm accessions, but there is no literature report of their use in fonio. This paper reports theresult of protocol optimization research for DNA isolation and RAPD analyses in fonio. High quality DNA was successfully isolated and RAPD was effectively used to study genetic similarity among fonio accessions. This result might stimulate the application of DNA markers to investigate the origin and phylogeny of fonio in Africa

    Local Stability Analysis of an Infection-Age Mathematical Model for Tuberculosis Disease Dynamics

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    An infection age structured mathematical model for tuberculosis disease dynamics is investigated in this paper. The infectious population is structured according to time and age of infection. An explicit formula for the basic reproductive number, R0 of the model is obtained. We showed that the disease-free equilibrium (DFE) state is locally asymptotically stable if R0 < 1 and unstable if otherwise. This simply means that tuberculosis could be controlled in a population when the basic reproduction number is less than unity.Keywords: Basic reproduction number; Infection-age; Local Stability; Tuberculosi

    Selective Modulation of α5 GABAA Receptors Exacerbates Aberrant Inhibition at Key Hippocampal Neuronal Circuits in APP Mouse Model of Alzheimer’s Disease

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    Selective negative allosteric modulators (NAMs), targeting α5 subunit-containing GABAA receptors (GABAARs) as potential therapeutic targets for disorders associated with cognitive deficits, including Alzheimer’s disease (AD), continually fail clinical trials. We investigated whether this was due to the change in the expression of α5 GABAARs, consequently altering synaptic function during AD pathogenesis. Using medicinal chemistry and computational modeling, we developed aqueous soluble hybrids of 6,6-dimethyl-3-(2-hydroxyethyl) thio-1-(thiazol-2-yl)-6,7-dihydro-2-benzothiophene-4(5H)-one, that demonstrated selective binding and high negative allosteric modulation, specifically for the α5 GABAAR subtypes in constructed HEK293 stable cell-lines. Using a knock-in mouse model of AD (APPNL−F/NL−F), which expresses a mutant form of human amyloid-ÎČ (AÎČ), we performed immunofluorescence studies combined with electrophysiological whole-cell recordings to investigate the effects of our key molecule, α5-SOP002 in the hippocampal CA1 region. In aged APPNL−F/NL−F mice, selective preservation of α5 GABAARs was observed in, calretinin- (CR), cholecystokinin- (CCK), somatostatin- (SST) expressing interneurons, and pyramidal cells. Previously, we reported that CR dis-inhibitory interneurons, specialized in regulating other interneurons displayed abnormally high levels of synaptic inhibition in the APPNL−F/NL−F mouse model, here we show that this excessive inhibition was “normalized” to control values with bath-applied α5-SOP002 (1 ÎŒM). However, α5-SOP002, further impaired inhibition onto CCK and pyramidal cells that were already largely compromised by exhibiting a deficit of inhibition in the AD model. In summary, using a multi-disciplinary approach, we show that exposure to α5 GABAAR NAMs may further compromise aberrant synapses in AD. We, therefore, suggest that the α5 GABAAR is not a suitable therapeutic target for the treatment of AD or other cognitive deficits due to the widespread neuronal-networks that use α5 GABAARs

    Precision mass measurements on neutron-rich rare-earth isotopes at JYFLTRAP - reduced neutron pairing and implications for the rr-process calculations

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    The rare-earth peak in the rr-process abundance pattern depends sensitively on both the astrophysical conditions and subtle changes in nuclear structure in the region. This work takes an important step elucidating the nuclear structure and reducing the uncertainties in rr-process calculations via precise atomic mass measurements at the JYFLTRAP double Penning trap. 158^{158}Nd, 160^{160}Pm, 162^{162}Sm, and 164−166^{164-166}Gd have been measured for the first time and the precisions for 156^{156}Nd, 158^{158}Pm, 162,163^{162,163}Eu, 163^{163}Gd, and 164^{164}Tb have been improved considerably. Nuclear structure has been probed via two-neutron separation energies S2nS_{2n} and neutron pairing energy metrics DnD_n. The data do not support the existence of a subshell closure at N=100N=100. Neutron pairing has been found to be weaker than predicted by theoretical mass models. The impact on the calculated rr-process abundances has been studied. Substantial changes resulting in a smoother abundance distribution and a better agreement with the solar rr-process abundances are observed.Comment: 8 pages, 4 figures, accepted for publication in Physical Review Letter

    Compressed gas domestic aerosol valve design using high viscous product

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    Most of the current universal consumer aerosol products using high viscous product such as cooking oil, antiperspirants, hair removal cream are primarily used LPG (Liquefied Petroleum Gas) propellant which is unfriendly environmental. The advantages of the new innovative technology described in this paper are: i. No butane or other liquefied hydrocarbon gas is used as a propellant and it replaced with Compressed air, nitrogen or other safe gas propellant. ii. Customer acceptable spray quality and consistency during can lifetime iii. Conventional cans and filling technology There is only a feasible energy source which is inert gas (i.e. compressed air) to replace VOCs (Volatile Organic Compounds) and greenhouse gases, which must be avoided, to improve atomisation by generating gas bubbles and turbulence inside the atomiser insert and the actuator. This research concentrates on using “bubbly flow” in the valve stem, with injection of compressed gas into the passing flow, thus also generating turbulence. The new valve designed in this investigation using inert gases has advantageous over conventional valve with butane propellant using high viscous product (> 400 Cp) because, when the valving arrangement is fully open, there are negligible energy losses as fluid passes through the valve from the interior of the container to the actuator insert. The use of valving arrangement thus permits all pressure drops to be controlled, resulting in improved control of atomising efficiency and flow rate, whereas in conventional valves a significant pressure drops occurs through the valve which has a complex effect on the corresponding spray

    Carbazole ligands as c-myc G-quadruplex binders

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    The interactions of c-myc G-quadruplex with three carbazole derivatives were investigated by UV-Vis spectrophotometry, fluorescence, CD spectroscopy, and molecular modeling. The results showed that a combination of carbazole scaffold functionalized with ethyl, triazole and imidazole groups resulted in stabilization of the intramolecular G-quadruplex formed by the DNA sequence derived from the NHE III1 region of c-myc oncogene (Pu22). Binding to the G-quadruplex Pu22 resulted in the significant increase in fluorescence intensity of complexed ligands 1-3. All ligands were capable of interacting with G4 DNA with binding stoichiometry indicating that two ligand molecules bind to G-quadruplex with comparable affinity, which agrees with binding model of end-stacking on terminal G-tetrads
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