scholarly journals Viral Infection Dynamics Model Based on a Markov Process with Time Delay between Cell Infection and Progeny Production

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1207 ◽  
Author(s):  
Igor Sazonov ◽  
Dmitry Grebennikov ◽  
Mark Kelbert ◽  
Andreas Meyerhans ◽  
Gennady Bocharov
Keyword(s):  
Statistical Characteristics ◽  
Virus Dynamics ◽  
Large Species ◽  
Virus Infections ◽  
Dynamics Model ◽  
Cell Infection ◽  
Human Virus ◽  
Infection Dynamics ◽  
A Cell ◽  
Model Components

Many human virus infections including those with the human immunodeficiency virus type 1 (HIV) are initiated by low numbers of founder viruses. Therefore, random effects have a strong influence on the initial infection dynamics, e.g., extinction versus spread. In this study, we considered the simplest (so-called, ‘consensus’) virus dynamics model and incorporated a delay between infection of a cell and virus progeny release from the infected cell. We then developed an equivalent stochastic virus dynamics model that accounts for this delay in the description of the random interactions between the model components. The new model is used to study the statistical characteristics of virus and target cell populations. It predicts the probability of infection spread as a function of the number of transmitted viruses. A hybrid algorithm is suggested to compute efficiently the system dynamics in state space domain characterized by the mix of small and large species densities.

scholarly journals Qualitative Analysis of a Generalized Virus Dynamics Model with Both Modes of Transmission and Distributed Delays

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Khalid Hattaf ◽  
Noura Yousfi
Keyword(s):  
Qualitative Analysis ◽  
Distributed Delays ◽  
Virus Dynamics ◽  
Dynamics Model ◽  
Cell Infection ◽  
Modes Of Transmission ◽  
Proposed Model ◽  
Infection Models ◽  
Infected Cells ◽  
Incidence Functions

We propose a generalized virus dynamics model with distributed delays and both modes of transmission, one by virus-to-cell infection and the other by cell-to-cell transfer. In the proposed model, the distributed delays describe (i) the time needed for infected cells to produce new virions and (ii) the time necessary for the newly produced virions to become mature and infectious. In addition, the infection transmission process is modeled by general incidence functions for both modes. Furthermore, the qualitative analysis of the model is rigorously established and many known viral infection models with discrete and distributed delays are extended and improved.

scholarly journals Diminished LcrV Secretion Attenuates Yersinia pseudotuberculosis Virulence

2007 ◽  
Vol 189 (23) ◽  
pp. 8417-8429 ◽  
Author(s):  
Jeanette E. Bröms ◽  
Matthew S. Francis ◽  
Åke Forsberg
Keyword(s):  
Type Iii Secretion ◽  
Yersinia Pseudotuberculosis ◽  
Signal Sequence ◽  
Infection Model ◽  
Target Cells ◽  
Cell Infection ◽  
Host Cell Membrane ◽  
Type Iii ◽  
A Cell

ABSTRACT Many gram-negative bacterial pathogenicity factors that function beyond the outer membrane are secreted via a contact-dependent type III secretion system. Two types of substrates are predestined for this mode of secretion, namely, antihost effectors that are translocated directly into target cells and the translocators required for targeting of the effectors across the host cell membrane. N-terminal secretion signals are important for recognition of the protein cargo by the type III secretion machinery. Even though such signals are known for several effectors, a consensus signal sequence is not obvious. One of the translocators, LcrV, has been attributed other functions in addition to its role in translocation. These functions include regulation, presumably via interaction with LcrG inside bacteria, and immunomodulation via interaction with Toll-like receptor 2. Here we wanted to address the significance of the specific targeting of LcrV to the exterior for its function in regulation, effector targeting, and virulence. The results, highlighting key N-terminal amino acids important for LcrV secretion, allowed us to dissect the role of LcrV in regulation from that in effector targeting/virulence. While only low levels of exported LcrV were required for in vitro effector translocation, as deduced by a cell infection assay, fully functional export of LcrV was found to be a prerequisite for its role in virulence in the systemic murine infection model.

scholarly journals Lifetime Prediction for a Cell-on-Board (COB) Light Source Based on the Adaptive Neuro-Fuzzy Inference System (ANFIS)

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
İsmail Kıyak ◽  
Gökhan Gökmen ◽  
Gökhan Koçyiğit
Keyword(s):  
Fuzzy Inference ◽  
Prediction Method ◽  
Operating Conditions ◽  
Lifetime Prediction ◽  
Statistical Characteristics ◽  
Ambient Conditions ◽  
Inference System ◽  
Initial Task ◽  
Neuro Fuzzy ◽  
A Cell

Predicting the lifetime of a LED lighting system is important for the implementation of design specifications and comparative analysis of the financial competition of various illuminating systems. Most lifetime information published by LED manufacturers and standardization organizations is limited to certain temperature and current values. However, as a result of different working and ambient conditions throughout the whole operating period, significant differences in lifetimes can be observed. In this article, an advanced method of lifetime prediction is proposed considering the initial task areas and the statistical characteristics of the study values obtained in the accelerated fragmentation test. This study proposes a new method to predict the lifetime of COB LED using an artificial intelligence approach and LM-80 data. Accordingly, a database with 6000 hours of LM-80 data was created using the Neuro-Fuzzy (ANFIS) algorithm, and a highly accurate lifetime prediction method was developed. This method reveals an approximate similarity of 99.8506% with the benchmark lifetime. The proposed methodology may provide a useful guideline to lifetime predictions of LED-related products which can also be adapted to different operating conditions in a shorter time compared to conventional methods. At the same time, this method can be used in the life prediction of nanosensors and can be produced with the 3D technique.

Dynamical Analysis of Multipathways and Multidelays of General Virus Dynamics Model

2019 ◽  
Vol 29 (03) ◽  
pp. 1950031 ◽  
Author(s):  
Ángel G. Cervantes-Pérez ◽  
Eric Ávila-Vales
Keyword(s):  
Immune Response ◽  
Time Delays ◽  
Reproduction Number ◽  
Dynamical Analysis ◽  
Multiple Time Scales ◽  
Threshold Dynamics ◽  
Positive Equilibrium ◽  
Virus Dynamics ◽  
Multiple Time ◽  
Dynamics Model

This paper considers a general virus dynamics model with cell-mediated immune response and direct cell-to-cell infection modes. The model incorporates two types of intracellular distributed time delays and a discrete delay in the CTL immune response. Under certain conditions, the model exhibits a global threshold dynamics with respect to two parameters: the basic reproduction number and the reproduction number of immune response. We use suitable Lyapunov functionals and apply Lasalle’s invariance principle to establish the global asymptotic stability of the two boundary equilibria. We also perform a bifurcation analysis for the positive equilibrium to show that the time delays may lead to sustained oscillations. To determine the direction of the Hopf bifurcation and the stability of the periodic solutions, the method of multiple time scales is applied. Finally, we carry out numerical simulations to illustrate our results.

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