543 research outputs found
RELATIONSHIP BETWEEN SYSTEMIC AND CENTRAL NERVOUS SYSTEM MONOCYTE/MACROPHAGE INFECTION IN SIMIAN IMMUNODEFICIENCY VIRUS ENCEPHALITIS
Approximately ¼ of AIDS patients develop HIVE, the pathologic entity associated with cognitive, motor, and behavioral deficits attributed to synaptic damage and neuronal loss. It still remains unclear why only a subset of HIV-infected individuals develops abundant central nervous system (CNS) macrophage/microglia infection that characterizes HIVE. The overarching hypothesis of this body of work is that simian immunodeficiency virus (SIV) encephalitis (SIVE) is the CNS manifestation of a systemic increase in SIV infection and activation of monocyte/macrophage elements. Specifically, we examined the relationship of infected and activated monocyte/macrophage elements outside of the CNS during the evolution of lentiviral encephalitis to the presence of infected macrophages in the CNS. We studied three models of SIV infection: SIV-infection of rhesus and pigtailed macaques and SIV-infection of CD8+ T cell depleted macaques. Antibody-mediated CD8+ T cell depletion did not increase the incidence of SIVE in infected rhesus macaques. In SIV-infected rhesus macaques, we examined whether presence of activated macrophages or SIV-infected macrophages is associated with the presence of neuronal damage. The presence of abundant infected macrophages in the CNS is related to postsynaptic neuronal damage in macaques with SIVE. At the same time cerebrospinal fluid viral load increased in SIV-infected CD8-depleted rhesus and non-depleted pigtailed macaques that developed encephalitis, monocyte-derived macrophages produced more virus ex vivo than macaques that did not develop encephalitis. Compared to pigtailed macaques that did not develop SIVE, the monocyte associated SIV-DNA load of monocytes was elevated in macaques that developed SIVE. Pigtailed macaques with SIVE had more infected macrophages in peripheral organs, with the exception of lymph nodes, than macaques without SIVE. Longitudinal analysis of phenotypic markers of monocyte activation show that increases in proportion of CD14+/CD16+ monocytes is associated with chronic disease. Brains with SIVE have greater numbers of T cells with cytotoxic potential. In conclusion, these findings suggest that inherent differences in host macrophage viral production or immune response to macrophage infection are associated with development of encephalitis. Further understanding of the differential role monocyte/macrophages have in the development of lentiviral encephalitis will identify therapeutic targets to halt this public health epidemic
Heat transfer coefficients for liquid hydrogen turbopumps
Empirical equations were derived to establish the appropriate heat transfer coefficients as functions of the temperature drops and heat transfer rates for a wide range of convective and boiling conditions at different locations in a liquid hydrogen turbopump
A Public Transport Ticket that Moved a Country: Assessing the Value of the German 9-Euro-Ticket as a Socio-Technical Experiment
This paper examines the German 9-Euro-Ticket from summer 2022 as a socio-technical experiment. Based on a systematic literature review of evaluations and accompanying research, three categories of learning processes are distinguished. The results suggest that the 9-Euro-Ticket enabled technological, social and institutional learning. Thus, the study provides a new perspective on this temporary policy and underscores the value of experimentation as a governance tool for the transition to sustainable mobility. This value goes beyond the direct traffic-related impact: The contribution of the 9-Euro-Ticket to a new stable configuration, the 'Germany ticket', is identified as the main output
Multiphase PC/PL Relations: Comparison between Theory and observations
Cepheids are fundamental objects astrophysically in that they hold the key to
a CMB independent estimate of Hubble's constant. A number of researchers have
pointed out the possibilities of breaking degeneracies between Omega_Matter and
H0 if there is a CMB independent distance scale accurate to a few percent (Hu
2005). Current uncertainties in the distance scale are about 10% but future
observations, with, for example, the JWST, will be capable of estimating H0 to
within a few percent. A crucial step in this process is the Cepheid PL
relation. Recent evidence has emerged that the PL relation, at least in optical
bands, is nonlinear and that neglect of such a nonlinearity can lead to errors
in estimating H0 of up to 2 percent. Hence it is important to critically
examine this possible nonlinearity both observationally and theoretically.
Existing PC/PL relations rely exclusively on evaluating these relations at mean
light. However, since such relations are the average of relations at different
phases. Here we report on recent attempts to compare theory and observation in
the multiphase PC/PL planes. We construct state of the art Cepheid pulsations
models appropriate for the LMC/Galaxy and compare the resulting PC/PL relations
as a function of phase with observations. For the LMC, the (V-I) period-color
relation at minimum light can have quite a narrow dispersion (0.2-0.3 mags) and
thus could be useful in placing constraints on models. At longer periods, the
models predict significantly redder (by about 0.2-0.3 mags) V-I colors. We
discuss possible reasons for this and also compare PL relations at various
phases of pulsation and find clear evidence in both theory and observations for
a nonlinear PL relation.Comment: 5 pages, 8 figures, proceeding for "Stellar Pulsation: Challenges for
Theory and Observation", Santa Fe 200
Large scale recyclable monolithic methyltrimethoxysilane aerogels formed by self-reinforcement
Perspectives for the VITO beam line at ISOLDE, CERN
By using polarized ion beams in combination with the β-NMR technique, the Versatile Ion-polarized Techniques On-line (VITO) experiment at ISOLDE, CERN links together expertise from different fields in an unique experimental setup. An overview of the experimental techniques and a general description of the newly designed beam line are presented. Potential uses in multidisciplinary research and perspectives for future experiments are discussed
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