Molecular epidemiological study of clinical cases of acute hepatitis E in Belarus

Relevance. The frequency of occurrence of anamnestic antibodies to the hepatitis E virus (HEV) in the general population of the Republic of Belarus is 7.3%, which is clearly not consistent with the low incidence of hepatitis E (HE). Most of primary HEV infections remain undiagnosed. The intensive epidemic process of HEV in the Belarusian population is hidden. Conducting epidemiological studies, including genotyping of HEV sequences isolated on the territory of the republic, makes it possible to more accurately characterize the sources of HEV infection and the mechanisms of its transmission. Aim molecular epidemiological study of two cases of acute hepatitis E detected in patients from Belarus. Materials and methods. During 20212022, samples of biological material were obtained from two patients undergoing treatment with an established diagnosis of acute hepatitis E. Serum samples were tested to detect antibodies to HEV using enzyme immunoassay, HEV RNA was detected in fecal samples using nested RT-PCR. The nucleotide sequence was determined by an automatic sequencer using the Sanger method. Analysis of nucleotide sequences, their genotyping, and calculation of evolutionary distances were performed using MEGA X software. Results. The HEV sequence isolated from a pregnant woman who had an epidemiological episode of alimentary contact with raw pork meat is clustered into a common phylogenetic clade with HEV sequence obtained from the patient from Belarus with a history of kidney transplantation and HEV sequences isolated from a domestic pigs. The HEV sequence isolated from a patient with a history of travel to Pakistan belongs to the HEV genotype 1 and joins a clade of HEV sequences isolated in Pakistan, India, Nepal and Mongolia

A new approximate model of tyre accounting for both deformed state and dry friction forces in the contact spot on the background of the coupled model

A new approximate model of the tire rolling accounting for coupled longitudinal and lateral sliding as well as the spinning and the deformed state resulting in elastic forces is proposed. The main goal of this investigation consists in the construction of simple models with a few of degrees of freedom allowing one to implement them analytically in the engineering practice, primarily for the estimation of the rolling stability and for the prognosis of the instable rolling so-called ”shimmy phenomenon” and to numerical simulation of the transient dynamics of rolling wheels with sliding effects. Such a model could become useful at the earlier stages of the engineering design instead of complex numerical models that are usually resource consuming. The known models of the shimmy phenomenon are usually based on the nonholonomic condition of the steady rolling and consider as the main cause of instability only the tire deformation while the sliding and spinning are assumed to vanish, i. e. the dry friction effects are neglected. Another type of models consists in the ”rigid wheel” assumption, in other words only the dry friction effects are accounted on the background of the coupled dry friction theory whereas the deformed state effects are neglected. Such a theory is based on the complete accounting of the combined kinematics due to simultaneous sliding and spin and shows its efficiency for slightly deformed wheels and the unsteady rolling regimes. Our goal consists in the formulation of the combined model that takes into account as well as the deformed state as the dry friction effects. This model is based on the solution of some model problems for the tire using solid finite element simulation or various shell theories, the computing of a set of specific generalized rigidity factors for the tire model, and on the accounting for the shape of the contact spot and the contact pressure distribution after the numerical simulation of the tire-road contact interaction in quasi-statics. As a result, we obtain a model with only a few degrees of freedom but more general that the Keldysh’s or Klimov’s ones