The search session has expired. Please query the service again.
Displaying 261 –
280 of
347
Recently, adult stem cells have become a focus of intensive biomedical research, but the
complex regulation that allows a small population of stem cells to replenish depleted tissues is still
unknown. It has been suggested that specific tissue structures delimit the spaces where stem cells
undergo unlimited proliferation (stem cell niche). In contrast, mathematical analysis suggests that
a feedback control of stem cells on their own proliferation and differentiation (denoted Quorum
Sensing) suffices...
Infectious diseases may have multiple infectious stages with very different epidemiological attributes,
including infectivity and disease progression. These stages are often
assumed to have exponentially distributed durations in epidemiological models. However,
models that use the exponential distribution assumption (EDA) may generate biased and
even misleading results in some cases. This discrepancy is particularly damaging if the models
are employed to assist policy-makers in disease control...
In this paper we have considered a nonlinear and nonautonomous stage-structured HIV/AIDS
epidemic model with an imperfect HIV vaccine, varying total population size and
distributed time delay to become infectious due to intracellular delay between initial
infection of a cell by HIV and the release of new virions. Here, we have established some
sufficient conditions on the permanence and extinction of the disease by using inequality
analytical technique....
We study the mathematical properties of a general model of cell division structured
with several internal variables. We begin with a simpler and specific model with two variables, we
solve the eigenvalue problem with strong or weak assumptions, and deduce from it the long-time
convergence. The main difficulty comes from natural degeneracy of birth terms that we overcome
with a regularization technique. We then extend the results to the case with several parameters and
recall the link between this...
We analyze and suggest improvements to a recently developed approximate continuum-electrostatic model for proteins. The model, called BIBEE/I (boundary-integral based electrostatics estimation with interpolation), was able to estimate electrostatic solvation free energies to within a mean unsigned error of 4% on a test set of more than 600 proteins¶a significant improvement over previous BIBEE models. In this work, we tested the BIBEE/I model for its capability to predict residue-by-residue interactions...
A basic mathematical model of the immune response when cancer cells are recognized is proposed. The model consists of six ordinary differential equations. It is extended by taking into account two types of immunotherapy: active immunotherapy and adoptive immunotherapy. An analysis of the corresponding models is made to answer the question which of the presented methods of immunotherapy is better. The analysis is completed by numerical simulations which show that the method of adoptive immunotherapy...
The paper deals with the issue of self-organization in applied sciences. It is particularly related to the emergence of Turing patterns. The goal is to analyze the domain size driven instability: We introduce the parameter , which scales the size of the domain. We investigate a particular reaction-diffusion model in 1-D for two species. We consider and analyze the steady-state solution. We want to compute the solution branches by numerical continuation. The model in question has certain symmetries....
Plants and animals have highly ordered structure both in time and in space, and one of the main questions of modern developmental biology is the transformation of genetic information into the regular structure of organism. Any multicellular plant begins its development from the universal unicellular state and acquire own species-specific structure in the course of cell divisions, cell growth and death, according to own developmental program. However the cellular mechanisms of plant development are...
In this paper we deal with a model describing the evolution in time of the density of a
neural population in a state space, where the state is given by Izhikevich’s two -
dimensional single neuron model. The main goal is to mathematically describe the
occurrence of a significant phenomenon observed in neurons populations, the
synchronization. To this end, we are making the transition to phase
density population, and use Malkin theorem to calculate...
Many cancer-associated genes and pathways remain to be identified in order to clarify the
molecular mechanisms underlying cancer progression. In this area, genome-wide
loss-of-function screens appear to be powerful biological tools, allowing the accumulation
of large amounts of data. However, this approach currently lacks analytical tools to
exploit the data with maximum efficiency, for which systems biology methods analyzing
complex cellular networks...
Tuberculosis (TB) remains a major global health problem. A possible risk factor for TB is
diabetes (DM), which is predicted to increase dramatically over the next two decades,
particularly in low and middle income countries, where TB is widespread. This study aimed
to assess the strength of the association between TB and DM. We present a deterministic
model for TB in a community in order to determine the impact of DM in the spread of the
disease....
Currently displaying 261 –
280 of
347