Journal of Mathematical and Fundamental Sciences
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Analysis of SIS-SI Stochastic Model with CTMC on the Spread of Malaria Disease
Full text linkVarious mathematical models have been developed to describe the transmission of malaria disease. The purpose of this study was to modify an existing mathematical model of malaria disease by using a CTMC stochastic model. The investigation focused on the transition probability, the basic reproduction number (R0), the outbreak probability, the expected time required to reach a disease-free equilibrium, and the quasi-stationary probability distribution. The population system will experience disease outbreak if R0>1, whereas an outbreak will not occur in the population system if R0≤1. The probability that a mosquito bites an infectious human is denoted as k, while θ is associated with human immunity. Based on the numerical analysis conducted, k and θ have high a contribution to the distribution of malaria disease. This conclusion is based on their impact on the outbreak probability and the expected time required to reach a disease-free equilibrium
Role of Hypoxia on Growth and Differentiation of Human Adipose Derived Stem Cells Grown on Silk Fibroin Scaffold Induced by Platelet Rich Plasma
Full text linkPrevious research has proven that 10% platelet-rich plasma (PRP) can enhance growth and differentiation of human adipose derived stem cells (hADSC) grown on silk fibroin scaffold into chondrocytes. A low oxygen concentration (hypoxia) condition is an important factor that potentially affects the ability of hADSC to grow and differentiate. The objective of this research was to analyze the difference in growth and differentiation capacity of hADSC grown on salt leached silk fibroin scaffold supplemented by 10% PRP under normoxic and hypoxic conditions. The growth capacity of the hADSC was determined by MTT assay and differentiation was tested using glycosaminoglycan (GAG) content analysis, while chondrocyte markers were visualized with the immunocytochemistry (ICC) method. This research observed hADSC proliferation under normoxic and hypoxic conditions for 21 days. Visualization of type 2 collagen showed that it was more abundant under hypoxia compared to normoxia. HIF-1α was only detected in the hADSC cultured in hypoxic conditions. In conclusion, culture under hypoxic conditions increases the capacity of hADSC to grow and differentiate into chondrocytes. This is the first study that has shown that hypoxia is able to enhance the proliferation and differentiation of hADSC grown on 3D salt leached silk fibroin scaffold supplemented by 10% PRP
Inherent Irreversibility of Mixed Convection within Concentric Pipes in a Porous Medium with Thermal Radiation
Full text linkThis work investigated the thermal putrefaction and inherent irreversibility in a steady flow of an incompressible inconstant viscosity radiating fluid within two concentric pipes filled with a porous medium. Following the Brinkmann-Darcy-Forchheimer approach, the nonlinear differential equations governing the model were obtained. The model boundary value problem was addressed numerically via a shooting quadrature with the Runge-Kutta-Fehlberg integration scheme. The effects of diverse emerging parameters on the fluid velocity, temperature, skin friction, Nusselt number, entropy generation rate and the Bejan number are provided in graphs and discussed in this paper
Delay Time Parameter and Its Confidence Interval of Predictive Time Series of COVID-19 Outbreak Between the First and the Second Wave
Full text linkThe outbreak of coronavirus disease 2019 (COVID-19) has become a major problem facing humans all around the world. For governments, in order to deal with the outbreak and protect the population, it is important to predict the number of infectious cases in the future to monitor the COVID-19 situation. This research aimed to compare the effectiveness of the logistic and the delay logistic time series in predicting the total number of infectious cases by using actual data from four countries, i.e. Thailand, South Korea, Egypt, and Nigeria. The total number of COVID-19 cases was collected during the first and the second wave of the COVID-19 outbreak. The validation and accuracy of the predictive growth curve time series were determined based on statistical values, i.e. the coefficient of determination and the root mean squared percentage error. It was found that the logistic time series was more appropriate for predicting the first wave in the four countries. For the second wave, the delay logistic time series was preferable. Moreover, the confidence interval based on Chebyshev’s inequality of delay time between the first and the second wave of the COVID-19 outbreak is also proposed
The Role of Non-pharmacological Interventions on the Dynamics of Schistosomiasis
Full text linkSchistosomiasis is a neglected tropical disease affecting communities surrounded by water bodies where fishing activities take place or people go to swim, wash and cultivate crops. It poses a great risk to the health and economic life of inhabitants of the area. This study was carried out to evaluate the impact of public health education and snail control measures on the incidence of schistosomiasis. A model was developed with attention given to the snail and human populations that are the hosts of the cercariae and miracidia respectively. The existence and stability of disease-free and endemic equilibrium states were established. The disease-free and endemic equilibrium states were shown to be locally asymptotically stable whenever the basic reproduction number was less than unity. Numerical simulations of the model were carried out to evaluate the impact of interventions (public health education and snail control measures) on schistosomiasis transmission. It was observed that the implementation of low coverage snail control with highly efficacious molluscicide and massive public health education will make the basic reproduction number smaller than unity, which implies the eradication of schistosomiasis in the population
A Study on Characteristics and Comparison of Evaporation Estimation Methods in Bandung
Full text linkThis study aims to understand the characteristic of evaporation and to evaluate the evaporation estimation methods to be employed in Bandung by using observation data at three different land cover characteristics sites, namely, densely vegetated area (Baleendah), densely built-up area (Ujung Berung), and mix of buildings and vegetation area (ITB). Observation data used are hourly evaporation, vapour pressure deficit, temperature, relative humidity, wind speed, and radiation. The analysis was done mostly by using statistical methods such as regression analysis and error comparison. The result shows the dominant weather factor affecting the evaporation in ITB and Ujung Berung is vapour pressure deficit, and in Baleendah is solar radiation. The methods of evaporation estimations used in this study are Trabert, Schendel, Turc, and CIMIS-Penman methods. The result shows that the original constant values of those methods are significantly correlated. However, the Schendel is found the most overestimated, and the second is Turc. The best estimated evaporation in Baleendah, ITB, and Ujung Berung is calculated using CIMIS-Penman with one hour lag of radiation, Trabert, and Calibrated Schendel, respectively. The improvement of constant value was applied to Schendel and the result is better than the original constants
Optimal Control Problem for Cholera Disease and Cost-Effectiveness Analysis
Full text linkCholera is a disease that continues to be a threat to public health globally and is an indicator of inequity and lack of social development in countries. For this reason, strategies for its control need to be investigated. In this work, an optimal control problem related to cholera disease was formulated by introducing personal protection, drug treatment and water sanitation as control strategies. First, the existence and characterization of controls to minimize the performance index or cost function was proved by using classic control theory. Then, the theoretical results were validated with numerical experiments by using data reported in the literature. Finally, the effectiveness and efficiency of the proposed controls were determined through a cost-effectiveness analysis. The results showed that the use of the three controls simultaneously is the cheapest and most effective strategy to control the disease
Docking Studies and Molecular Dynamics Simulation of Compounds Contained in Kaempferia Galanga L. to Lipoxygenase (LOX) for Anti-Inflammatory Drugs
Full text linkInflammation is a self-protective response to start the healing process. An anti-inflammatory target worth developing are lipoxygenase inhibitors, which have been studied for several diseases, including severe respiratory disease. This research had the goals of estimating the activity of 21 compounds from K. galanga to inhibit the lipoxygenase (LOX) and estimating the bond stability of the ligand-LOX complex. Based on the compound’s affinity for LOX, the compounds in K. galanga were selected by utilizing the PLANTS docking software, with zileuton as the reference ligand. The GROMACS application was used to simulate the molecular dynamics of the LOX-ligand complex at 310 K. Based on the chemPLP score, most of the 21 K. galanga compounds showed a higher affinity towards 5-LOX compared to zileuton. δ-3-carene had the best affinity for 5-LOX. In the simulation of molecular dynamics until 20 ns, the RMSD of δ-3-carene and 5-LOX was not more than 0.03 nm or 0.3 Å, indicating that the whole system showed decent stability and had ‑1.67392 x 106 kcal/mol as the average potential energy. The results showed that K. galanga contains active components of 5-LOX inhibitors that could be developed