1,609 research outputs found
Contact process on a Voronoi triangulation
We study the continuous absorbing-state phase transition in the contact
process on the Voronoi-Delaunay lattice. The Voronoi construction is a natural
way to introduce quenched coordination disorder in lattice models. We simulate
the disordered system using the quasistationary simulation method and determine
its critical exponents and moment ratios. Our results suggest that the critical
behavior of the disordered system is unchanged with respect to that on a
regular lattice, i.e., that of directed percolation
Multiscale model for the effects of adaptive immunity suppression on the viral therapy of cancer
Oncolytic virotherapy - the use of viruses that specifically kill tumor cells
- is an innovative and highly promising route for treating cancer. However, its
therapeutic outcomes are mainly impaired by the host immune response to the
viral infection. In the present work, we propose a multiscale mathematical
model to study how the immune response interferes with the viral oncolytic
activity. The model assumes that cytotoxic T cells can induce apoptosis in
infected cancer cells and that free viruses can be inactivated by neutralizing
antibodies or cleared at a constant rate by the innate immune response. Our
simulations suggest that reprogramming the immune microenvironment in tumors
could substantially enhance the oncolytic virotherapy in immune-competent
hosts. Viable routes to such reprogramming are either in situ virus-mediated
impairing of CD T cells motility or blockade of B and T lymphocytes
recruitment. Our theoretical results can shed light on the design of viral
vectors or new protocols with neat potential impacts on the clinical practice.Comment: 14 pages, 4 figure
An approximation to density functional theory for an accurate calculation of band-gaps of semiconductors
The local-density approximation (LDA), together with the half-occupation
(transition state) is notoriously successful in the calculation of atomic
ionization potentials. When it comes to extended systems, such as a
semiconductor infinite system, it has been very difficult to find a way to
half-ionize because the hole tends to be infinitely extended (a Bloch wave).
The answer to this problem lies in the LDA formalism itself. One proves that
the half-occupation is equivalent to introducing the hole self-energy
(electrostatic and exchange-correlation) into the Schroedinger equation. The
argument then becomes simple: the eigenvalue minus the self-energy has to be
minimized because the atom has a minimal energy. Then one simply proves that
the hole is localized, not infinitely extended, because it must have maximal
self-energy. Then one also arrives at an equation similar to the SIC equation,
but corrected for the removal of just 1/2 electron. Applied to the calculation
of band gaps and effective masses, we use the self-energy calculated in atoms
and attain a precision similar to that of GW, but with the great advantage that
it requires no more computational effort than standard LDA.Comment: Zip file containing .tex and 6 .ps figure
CD4 T follicular cells and B cells
© 2023 Wiley-VCH GmbH.Regulatory and effector cell responses to Plasmodium vivax, the most common human malaria parasite outside Africa, remain understudied in naturally infected populations. Here, we describe peripheral CD4 + T- and B-cell populations during and shortly after an uncomplicated P. vivax infection in 38 continuously exposed adult Amazonians. Consistent with previous observations, we found an increased frequency in CD4 + CD45RA - CD25 + FoxP3 + T regulatory cells that express the inhibitory molecule CTLA-4 during the acute infection, with a sustained expansion of CD21 - CD27 - atypical memory cells within the CD19 + B-cell compartment. Both Th1- and Th2-type subsets of CXCR5 + ICOS hi PD-1 + circulating T follicular helper (cTfh) cells, which are thought to contribute to antibody production, were induced during P. vivax infection, with a positive correlation between overall cTfh cell frequency and IgG antibody titers to the P. vivax blood-stage antigen MSP1 19 . We identified significant changes in cell populations that had not been described in human malaria, such as an increased frequency of CTLA-4 + T follicular regulatory cells that antagonize Tfh cells, and a decreased frequency of circulating CD24 hi CD27 + B regulatory cells in response to acute infection. In conclusion, we disclose a complex immunoregulatory network that is critical to understand how naturally acquired immunity develops in P. vivax malaria.publishersversionepub_ahead_of_prin
Borderline personality disorder and bias in the recognition of facial expressions of emotion: a pathway to understand the psychopathology
Background The identification of facial emotions is a key skill as it promotes rapid and accurate recognition of emotions and enables better communication and greater social adaptation. More recent studies have suggested that impaired social interactions may be related to deficits in social cognition and therefore in the recognition of facial expressions, contributing to social disturbance among individuals with borderline personality disorder (BPD). Objective To present the results of an empirical study assessing the recognition of facial emotion expressions in women with BPD, having as reference a group of healthy women from the general population. Methods The subjects (40 female with BPD and 40 controls) were assessed with a dynamic task on a computer screen for recognition of facial expressions of emotion. Results The BPD group had a lower accuracy in perceiving emotions of fear and surprise and slowness in recognising happiness. Logistic regression analyses also identified an association between BPD and higher sensitivity in the recognition of anger. Discussion Women with BPD made more mistakes in the recognition of negative emotions, which can bias the behaviour and regulation of affective states, favouring in turn the emergence of some typical symptoms associated with BPD
- …