Simulation of A Mathematical Model Of Hepatitis B Virus Transmission Dynamics In The Presence Of Vaccination And Treatment

In this paper, a mathematical model for the transmission dynamics of hepatitis B virus (HBV) infection incorporating vaccination and treatment as control parameters is presented. The basic reproduction number, , as a threshold parameter, was constructed, in terms of the given model parameters, by the next generation method.   was numerically assessed for its sensitivity to vaccination and treatment parameters. A unique disease-free equilibrium state was determined, indicating possibility of control of HBV disease. The model was solved numerically using Runge-Kutta method of order four to evaluate the effects of vaccination and treatment parameters on the prevalence of the disease. The numerical results of the sensitivity analysis show that increasing either vaccination or treatment rate has the potential of reducing  below unity. The results of the numerical simulations of the model show that effective vaccination, treatment or a combination of both of them as a control strategy can eradicate HBV disease, with the combination being far better than either of them. Finally, these findings strongly suggest that high coverage of vaccination and treatment are crucial to the success of HBV disease control

Modelling Hepatitis B Virus Transmission Dynamics In The Presence of Vaccination and Treatment

Hepatitis B is a global threat as over a billion people have been infected and about 300 million people die annually across the world. In this paper, a mathematical model for the transmission dynamics of hepatitis B virus infection considering vaccination and treatment as control parameters in the host population is presented. First, the disease-free equilibrium state of the model was determined. The next generation method was used to determine the basic reproduction number,  as a threshold parameter, in terms of the given model parameters.  was analytically evaluated for its sensitivity to vaccination and treatment parameters. It was proved that the disease-free equilibrium state is locally asymptotically stable if the  is below unity, otherwise, it is unstable. Local stability of the endemic equilibrium state was established using the centre manifold theory. The analytical results of the  show that increasing the proportion of people who receive vaccines, either at birth or later in life, reduces it below unity. Similarly, increasing the proportion of carriers who receive treatment achieves the same purpose. The result of the local stability analysis of the disease-free equilibrium state shows that the disease can be eliminated if  is below unity. The result of the centre manifold theory on the endemic equilibrium state shows that the disease can persist as the value of  increases above one. The findings of this study strongly suggest a combination of effective vaccination and treatment as a control strategy is crucial to the success of HBV disease control

Evaluation of A Four Stroke Compression-Ignition Engine with Load (100N).

A loaded four stroke compression ignition (Nissan Primera model) engine mounted in a heat engine laboratory of Enugu State University of Science and Technology Enugu was used for the exercise. An absorption dynamometer was attached to the engine to measure torque. As the engine was running, the speed was recorded with a digital tachometer at a time frame of 20 seconds. A lot of tests were carried out to determine a number of parameters like specific fuel consumption, mechanical efficiency, fuel mass flow rate, indicated power, brake power, brake horse power, rate of fuel consumption at different gear ratios. The data so obtained were tabulated and relationship between various parameters plotted in graphs. Results show that: volume of diesel consumed increases with increasing engine speed, increases with increasing gear; mass flow rate of diesel increases with increasing brake power, increases with increasing gear; specific fuel consumption decreases with increasing engine speed ; specific fuel consumption also decreases with increasing brake power; indicated power increases as engine speed increases. Keywords: Diesel Engine, Absorption Dynamometer, Tachometer, Engine Torque, Brake Horse Power, DOI: 10.7176/JETP/9-8-04 Publication date: November 30th 201

Design and Development of a Trapezoidal Plate Fin Heat Exchanger for the Prediction of Heat Exchanger Effectiveness

A trapezoidal plate-fin exchanger has been designed and developed, and an experimental test rig fabricated to test the plate fin heat exchanger. The heat exchanger was constructed in a 5 layer cross-flow arrangement. The length of the trapezoidal fins between the layers were 380mm and its height, thickness, top width and bottom width were 40mm, 0.5mm, 20mm, and 80mm respectively. A hot fluid test has been conducted to determine the thermo- hydraulic performance of the given heat exchanger at different mass flow rates (4.975 kg/s to 9.751 kg/s) at a hot inlet temperature of 369K. The values of the effectiveness obtained were plotted against the corresponding values mass flow rate to compare and evaluate the variation of the results. Thus, the performance of a heat exchanger with trapezoidal fins has been studied experimentally and it has been determined that: the mass flow rate of the fluids is proportional to the temperature drop of the fluids after passing through the exchanger. Also Increase in mass flow rate, increases the effectiveness of the heat exchanger. Improper insulation influenced heat transfers in heat exchanger cores and caused energy imbalance in the heat exchanger. This study suggests that the calculated effectiveness of 0.98 using trapezoidal plate fin heat exchanger result provides benchmark data to evaluate and predicts the performance of a plate-fin heat exchanger with trapezoidal fins for energy recovery application. Keywords: Heat exchanger development; trapezoidal fin, effectiveness, heat exchanger analysis; hot and cold fluids DOI: 10.7176/JETP/9-8-03 Publication date: November 30th 201

An Afro-Existential Approach to the Development of the Nigerian Society

The role of philosophy in nation building is hardly given the recognition it deserves in the African society. In this regard, philosophers are often seen as those who see problems where none exist, rather than people who inspire critical thinking. Yet, the role of philosophy in nation building cannot be dismissed with a wave of hand. The focus of this paper is basically to establish the relevance of existentialist philosophy to national development. To this end, we situate our discourse within a particular African context. The African world view would be discussed mainly from the context of the Igbo world view. This is the crux of the whole work. To this effect, the full implication of the Afro-existential approach will unfold as the work unfolds. One branch of philosophy that has made waves in various disciplines is existentialism. This paper is therefore an attempt to establish the relevance of existentialist philosophy to national development, with a particular focus on Nigeria. It understands existentialism as a trend in philosophy that lays emphasis on man's existence with regard to such themes as individual freedom and choice, and the individual creating meaning in a meaningless universe. In this connection, it examines the role of the Afro-existential discourse as a new approach in African philosophy. It addresses such questions as, why is Nigeria underdeveloped. Do we have to continue looking for historical forces or factors to blame? What can the philosopher and the existential discourse contribute to the development of Nigeria? It concludes that, confronted with the underdeveloped state of Nigeria, the existentialists do not overly ignore history. However, they are more concerned with the present situation and the choices that confront us as individuals. Making the right choices and taking the right steps today is therefore the way philosophers would establish their relevance through the existential discourse

Knowledge, perceptions and myths regarding infertility among selected adult population in Pakistan: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>The reported prevalence of infertility in Pakistan is approximately 22% with 4% primary and 18% secondary infertility. Infertility is not only a medical but also a social problem in our society as cultural customs and perceived religious dictums may equate infertility with failure on a personal, interpersonal, or social level. It is imperative that people have adequate knowledge about infertility so couples can seek timely medical care and misconceptions can be rectified.</p> <p>We aim to assess the knowledge, perception and myths regarding infertility and suggest ways to improve it.</p> <p>Methods</p> <p>A cross-sectional survey was carried out by interviewing a sample of 447 adults who were accompanying the patients at two tertiary care hospitals in Karachi, Pakistan. They were interviewed one-on-one with the help of a pretested questionnaire drafted by the team after a thorough literature review and in consultation with infertility specialists.</p> <p>Results</p> <p>The correct knowledge of infertility was found to be limited amongst the participants. Only 25% correctly identified when infertility is pathological and only 46% knew about the fertile period in women's cycle. People are misinformed that use of IUCD (53%) and OCPs (61%) may cause infertility. Beliefs in evil forces and supernatural powers as a cause of infertility are still prevalent especially amongst people with lower level of education. Seeking alternative treatment for infertility remains a popular option for 28% of the participant as a primary preference and 75% as a secondary preference. IVF remains an unfamiliar (78%) and an unacceptable option (55%).</p> <p>Conclusions</p> <p>Knowledge about infertility is limited in the population and a lot of misconceptions and myths are prevalent in the society. Alternative medicine is a popular option for seeking infertility treatment. The cultural and religious perspective about assisted reproductive technologies is unclear, which has resulted in its reduced acceptability.</p

Genetic Control of Resistance to Trypanosoma brucei brucei Infection in Mice

Trypanosoma brucei are extracellular protozoa transmitted to mammalian host by the tsetse fly. They developed several mechanisms that subvert host's immune defenses. Therefore analysis of genes affecting host's resistance to infection can reveal critical aspects of host-parasite interactions. Trypanosoma brucei brucei infects many animal species including livestock, with particularly severe effects in horses and dogs. Mouse strains differ greatly in susceptibility to T. b. brucei. However, genes controlling susceptibility to this parasite have not been mapped. We analyzed the genetic control of survival after T. b. brucei infection using CcS/Dem recombinant congenic (RC) strains, each of which contains a different random set of 12.5% genes of their donor parental strain STS/A on the BALB/c genetic background. The RC strain CcS-11 is even more susceptible to parasites than BALB/c or STS/A. In F2 hybrids between BALB/c and CcS-11 we detected and mapped four loci, Tbbr1-4 (Trypanosoma brucei brucei response 1–4), that control survival after T. b. brucei infection. Tbbr1 (chromosome 3) and Tbbr2 (chromosome 12) have independent effects, Tbbr3 (chromosome 7) and Tbbr4 (chromosome 19) were detected by their mutual inter-genic interaction. Tbbr2 was precision mapped to a segment of 2.15 Mb that contains 26 genes

Intestinal strongyloidiasis and hyperinfection syndrome

In spite of recent advances with experiments on animal models, strongyloidiasis, an infection caused by the nematode parasite Strongyloides stercoralis, has still been an elusive disease. Though endemic in some developing countries, strongyloidiasis still poses a threat to the developed world. Due to the peculiar but characteristic features of autoinfection, hyperinfection syndrome involving only pulmonary and gastrointestinal systems, and disseminated infection with involvement of other organs, strongyloidiasis needs special attention by the physician, especially one serving patients in areas endemic for strongyloidiasis. Strongyloidiasis can occur without any symptoms, or as a potentially fatal hyperinfection or disseminated infection. Th(2 )cell-mediated immunity, humoral immunity and mucosal immunity have been shown to have protective effects against this parasitic infection especially in animal models. Any factors that suppress these mechanisms (such as intercurrent immune suppression or glucocorticoid therapy) could potentially trigger hyperinfection or disseminated infection which could be fatal. Even with the recent advances in laboratory tests, strongyloidiasis is still difficult to diagnose. But once diagnosed, the disease can be treated effectively with antihelminthic drugs like Ivermectin. This review article summarizes a case of strongyloidiasis and various aspects of strongyloidiasis, with emphasis on epidemiology, life cycle of Strongyloides stercoralis, clinical manifestations of the disease, corticosteroids and strongyloidiasis, diagnostic aspects of the disease, various host defense pathways against strongyloidiasis, and available treatment options

Performance Evaluation of a Melon Seeds Shelling and Separation Machine

The scarcity of information on the performance of most machines developed in Nigeria impedes the commercialization of proven indigenous technologies. A newly developed melon seeds shelling and separation machine with the capability to continuously shell conditioned melon seeds and simultaneously separate the seed cotyledons from it shells was evaluated. The machine extracts heat exclusively from the exhaust gases of a gasoline prime mover by heat conduction principle, mildly dry the shelled melon seed mixture before effecting separation of the cotyledons from it shells by aerodynamic and screening principles. &nbsp;Based on preliminary studies, performance evaluation of the machine was carried out at 900, 1500 and 2100 rpm operating speed and 14, 20 and 26% db moisture content of white edge (Serewe) melon seed variety. The data obtained were analyzed using IBM SPSS statistic software version 25. Results of Analysis of Variance (ANOVA) at P ≤ 0.05 showed that, shelling efficiency and machine capacity varies significantly with the operating speed, moisture content of the seeds, and their interactions; while separation efficiency and seed breakage percentage varies significantly with the operating speed and moisture content of the seeds but not significant with their interactions. An optimal performance of 96% shelling efficiency, 95% separation efficiency, 2.67% seed breakage percentage and 54.23 kg/h machine capacity, was obtained at 2100 rpm operating speed and 20% db seed moisture level. The performance of the machine is satisfactory and therefore recommended for commercialization and adoption by melon seed processors