Analysis of a discrete mathematical COVID-19 model.

To describe the main propagation of the COVID-19 and has to find the control for the rapid spread of this viral disease in real life, in current manuscript a discrete form of the SEIR model is discussed. The main aim of this is to describe the viral disease in simplest way and the basic properties that are related with the nature of curves for susceptible and infected individuals are discussed here. The elementary numerical examples are given by using the real data of India and Algeria.

Effect of 6 months of aerobic training on adipokines as breast cancer risk factors in postmenopausal women: A randomized controlled trial.

PURPOSE: Physical activity has been introduced as an inexpensive and effective behavior to reduce postmenopausal breast cancer risk. Decreased concentrations of adipokines such as leptin and resistin may be a possible mechanism. This study aimed to investigate the effects of 6 months of aerobic training on leptin and resistin levels in postmenopausal women. MATERIALS AND METHODS: The study participants were 50-74 years old, sedentary and postmenopausal women. Forty-one women met the inclusion criteria and were randomly assigned to the training (n = 22) or the control group (n = 19). Participants in intervention group engaged in a moderate supervised aerobic training, 3 days per week for 6 months, while controls were asked not to change their physical activity levels for the duration of the trial. Plasma concentrations of leptin and resistin, aerobic fitness, and anthropometric measures were assessed at baseline and after 6 months. RESULTS: Twenty-seven out of 41 participants completed the study. Plasma leptin decreased by 0.6% in exercisers and increased by 8.2% in controls; however, the exercise effect was not statistically significant. Plasma concentrations of resistin also decreased by 16.1% and 15.1% in exercise and control group, respectively. Aerobic fitness increased, and body mass index (BMI) decreased significantly in the intervention group. CONCLUSIONS: The exercise intervention did not have a statistically significant impact on the concentrations of the adipokines in question; however, this long-term aerobic training reduced BMI and body fat percentage and enhanced aerobic fitness. Thus, exercise programs can be considered as an effective behavioral modification in breast cancer prevention.

Removal and recovery of copper and nickel ions from aqueous solution by poly(methacrylamide-co-acrylic acid)/montmorillonite nanocomposites.

Nanocomposite hydrogels based on poly(methacrylamide-co-acrylic acid) and nano-sized montmorillonite were prepared by aqueous dispersion and in situ radical polymerization. Optimum sorption conditions were determined as a function of montmorillonite content, contact time, pH, and temperature. The equilibrium data of Cu(2+) and Ni(2+) conformed to the Freundlich and Langmuir isotherms in terms of relatively high regression values. The maximum monolayer adsorption capacity of the nanocomposite hydrogel (with 3 wt% montmorillonite content), as obtained from the Langmuir adsorption isotherm, was found to be 49.26 and 46.94 mg g(-1) for Cu(2+) and Ni(2+), respectively, at contact time = 60 min, pH = 6.8, adsorbent dose = 100 mg/ml, and temperature = 318 K. Kinetic studies of single system indicated that the pseudo-second order is the best fit with a high correlation coefficient (R (2) = 0.97-0.99). The result of five times sequential adsorption-desorption cycle shows a good degree of desorption and a high adsorption efficiency.