40 research outputs found

    Bifurcation analysis of dynamical systems with fractional order differential equations via the modified Riemann-Liouville derivative

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    In this manuscript, the solutions of linear dynamical systems with fractional differential equations via themodified Riemann-Liouville derivative is derived. By using Jumarie type of derivative (JRL), we stated and provedthe Existence and uniqueness theorems of the dynamical systems with fractional order equations. Also a novel stability analysis of fractional dynamical systems by Jumarie type derivative is established and some important stability conditions are determined. The achieved results have various applications in mathematics, plasma physics and almost all branches of physics that have non-conservative forces. Finally, we investigated interesting application of nonlinear space-time fractional Korteweg-de Vries (STFKdV) equation in Saturn F-ring’s region. Moreover, our investigation could be basic interest to explain and interpret the effects of fractional and modification parameters on STFKdV equation. This is novel study on this model by dynamical system (DS) to describe the behavior of nonlinear waves without solve this system

    Molecular detection, phylogenetic analysis and genetic diversity of recently isolated foot-and-mouth disease virus serotype A African topotype, Genotype IV

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    Background Surveillance for circulating emerging diseases of economic importance has a major role in the rapid response to major pathogen outbreaks. Foot-and-mouth disease virus (FMDV) is one of the significant endemic viruses in Egypt. FMDV is periodically investigated for monitoring evolution and emergence of new variants. The genetic characterization of foot-and-mouth disease (FMD) virus serotype A responsible for recent outbreaks of FMD in Egypt was determined. Methods Samples were collected from different locations and virus isolation was performed using BHK-21 cells. Viral RNA was extracted and samples were screened for FMDV using real-time RT-PCR. DNA sequence analysis was performed and computational and bioinformatics analyses were used to determine the substitution rates and phylogenetic relationship. Results Sequence and phylogenetic analyses of full-length 1D region of FMDV samples collected from different governorates in 2020 showed close similarity to Egyptian FMDV strains from serotype A-African topotype-G-IV with genetic variation of 6.5%. Recently isolated FMDV strains showed high genetic variations from locally used vaccine strains in the major antigenic sites of VP1 region. Conclusions Although, efforts made by the veterinary authorities to implement an effective mass vaccination plan, the recently detected FMDV strains in this study could not be subtyped using the FMDV primers routinely used for molecular serotyping. These dissimilarities raise the alarm for reconsideration of the FMDV isolates used in vaccine manufacture. Clearly close monitoring of FMD in Egypt is urgently required to define the risks of future outbreaks and to ensure appropriate control measures against FMD major outbreaks

    Overview of African horse sickness virus (AHSV) situation in Egypt from 2017 to 2022

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    African horse sickness (AHS) is a non-contagious arthropod-borne infectious disease of Equidae. Because of its severity and quick spread, It is cosidered as a notifiable disease. The current study intended to look into the current suitation of the vector-borne African horse sickness virus (AHSV) in Egypt, determine viral seroprevelance, and assess the associated risk factors. In this context, 2739 sera and 150 spleen samples were collected from different Egyptian governorates and tested for AHSV screening. The sera were investigated for presence of antibodies against AHSV whilst spleen samples were tested for AHSV Ag and RNA detection. The obtained results revealed that all 2739 sera samples tested negative for AHSV antibodies. Furthermore, using ELISA and conventional reverse-transcription polymerase chain reaction (RT-PCR), to identify AHSV Ag and nucleic acid, the 150 tested spleen samples gave negative results with both assays. In conclusion, the recorded results indicated the absence of antibodies, antigen, and viral nucleic acid of AHSV in all tested samples which proved that there is no circulating virus in the investigated Egyptian governorates in the period from 2017 to 2022. Evenually, the effective control programs are recommended by carrying out further epidemiological investigations to understand the current situation of arboviruses in the country
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