186,064 research outputs found
Unravelling glioblastoma heterogeneity by means of single-cell RNA sequencing.
Glioblastoma (GBM) is the most invasive and deadliest brain cancer in adults. Its inherent heterogeneity has been
designated as the main cause of treatment failure. Thus, a deeper understanding of the diversity that shapes GBM
pathobiology is of utmost importance. Single-cell RNA sequencing (scRNA-seq) technologies have begun to
uncover the hidden composition of complex tumor ecosystems. Herein, a semi-systematic search of reference
literature databases provided all existing publications using scRNA-seq for the investigation of human GBM. We
compared and discussed findings from these works to build a more robust and unified knowledge base. All aspects
ranging from inter-patient heterogeneity to intra-tumoral organization, cancer stem cell diversity, clonal
mosaicism, and the tumor microenvironment (TME) are comprehensively covered in this report. Tumor
composition not only differs across patients but also involves a great extent of heterogeneity within itself. Spatial
and cellular heterogeneity can reveal tumor evolution dynamics. In addition, the discovery of distinct cell
phenotypes might lead to the development of targeted treatment approaches. In conclusion, scRNA-seq expands
our knowledge of GBM heterogeneity and helps to unravel putative therapeutic targets.post-print4967 K
A unified hyperbolic formulation for viscous fluids and elastoplastic solids
We discuss a unified flow theory which in a single system of hyperbolic
partial differential equations (PDEs) can describe the two main branches of
continuum mechanics, fluid dynamics, and solid dynamics. The fundamental
difference from the classical continuum models, such as the Navier-Stokes for
example, is that the finite length scale of the continuum particles is not
ignored but kept in the model in order to semi-explicitly describe the essence
of any flows, that is the process of continuum particles rearrangements. To
allow the continuum particle rearrangements, we admit the deformability of
particle which is described by the distortion field. The ability of media to
flow is characterized by the strain dissipation time which is a characteristic
time necessary for a continuum particle to rearrange with one of its
neighboring particles. It is shown that the continuum particle length scale is
intimately connected with the dissipation time. The governing equations are
represented by a system of first order hyperbolic PDEs with source terms
modeling the dissipation due to particle rearrangements. Numerical examples
justifying the reliability of the proposed approach are demonstrated.Comment: 6 figure
A unified framework for Schelling's model of segregation
Schelling's model of segregation is one of the first and most influential
models in the field of social simulation. There are many variations of the
model which have been proposed and simulated over the last forty years, though
the present state of the literature on the subject is somewhat fragmented and
lacking comprehensive analytical treatments. In this article a unified
mathematical framework for Schelling's model and its many variants is
developed. This methodology is useful in two regards: firstly, it provides a
tool with which to understand the differences observed between models;
secondly, phenomena which appear in several model variations may be understood
in more depth through analytic studies of simpler versions.Comment: 21 pages, 3 figure
A Dynamical Theory of Electron Transfer: Crossover from Weak to Strong Electronic Coupling
We present a real-time path integral theory for the rate of electron transfer
reactions. Using graph theoretic techniques, the dynamics is expressed in a
formally exact way as a set of integral equations. With a simple approximation
for the self-energy, the rate can then be computed analytically to all orders
in the electronic coupling matrix element. We present results for the crossover
region between weak (nonadiabatic) and strong (adiabatic) electronic coupling
and show that this theory provides a rigorous justification for the salient
features of the rate expected within conventional electron transfer theory.
Nonetheless, we find distinct characteristics of quantum behavior even in the
strongly adiabatic limit where classical rate theory is conventionally thought
to be applicable. To our knowledge, this theory is the first systematic
dynamical treatment of the full crossover region.Comment: 11 pages, LaTeX, 8 Postscript figures to be published in J. Chem.
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