2,198 research outputs found
Resummed propagators in multi-component cosmic fluids with the eikonal approximation
We introduce the eikonal approximation to study the effect of the large-scale
motion of cosmic fluids on their small-scale evolution. This approach consists
in collecting the impact of the long-wavelength displacement field into a
single or finite number of random variables, whose statistical properties can
be computed from the initial conditions. For a single dark matter fluid, we
show that we can recover the nonlinear propagators of renormalized perturbation
theory. These are obtained with no need to assume that the displacement field
follows the linear theory. Then we extend the eikonal approximation to many
fluids. In particular, we study the case of two non-relativistic components and
we derive their resummed propagators in the presence of isodensity modes.
Unlike the adiabatic case, where only the phase of small-scale modes is
affected by the large-scale advection field, the isodensity modes change also
the amplitude on small scales. We explicitly solve the case of cold dark
matter-baryon mixing and find that the isodensity modes induce only very small
corrections to the resummed propagators.Comment: 18 pages, 9 figures, matches published version as PR
Multiple acyl-CoA dehydrogenase deficiency and population newborn screening:Connecting the dots
Multiple acyl-CoA dehydrogenase deficiency (MADD; also known as glutaric aciduria type II) is an ultra-rare inborn error of metabolism (IEM). The disorder is not included in the Dutch newborn blood spot (NBS) screening program due to a lack of evidence for sufficient health gain upon early detection. Complicating factors concern the limited knowledge on the natural history, disease severity prediction and monitoring of the spectrum of MADD patients, and the absence of systematic evidence of an effective treatment for severely affected patients. MADD is also an exemplary IEM that can escape identification due to nonspecific symptoms and unexpected childhood death. In this thesis, we combined reviews of the literature, with experimental research and studies on clinical outcome in patients. In part I, we present the IEMs that are associated with unexpected death in early childhood, and how their detection through acylcarnitine profile analysis can be improved. We recommend that every child participates in a population NBS program, even after death. In part II, we describe that functional studies in patient fibroblasts can predict the MADD phenotype, we propose a clinical monitoring system, and we describe the efficacy and safety of D,L-3-hydroxybutyrate treatment in severe MADD. The results of this thesis can guide clinicians in their care of MADD patients and their families, and can also support decision-makers in their aims to improve NBS programs and facilitate access to novel treatments for (ultra-)rare diseases
Dendritic cells in asthma: a function beyond sensitization
The aim of this thesis is to characterize the involvement of dendritic cells in the induction and
maintenance of the secondary immune response leading to an eosinophilic airway inflammation as seen in asthma. Special attention was attributed to the mechanisms by which
these cells accumulate in the airways of challenged mice, to their interaction with primed
CD4+ T cells as well as to their functional contribution to primed T cell activation. These
questions were addressed in a well-established murine model of eosinophilic airway
inflammation Balb/c mice were sensitized to OVA by an intratracheal injection of OVA-pulsed bone
marrow-derived DCs. Ten days post-sensitization, mice were challenged with an aerosol of
the same antigen resulting in an eosinophilic airway inflammation as shown by histological
analysis of lungs revealing peribronchial and perivascular inflammatory infiltrates and goblet
cell hyperplasia, increased numbers of eosinophils in bronchoalveolar lavage fluid and Th2
cytokine production by draining lymph nodes of the lung. To determine the role of the dendritic cell in the secondary immune
response to inhaled allergen the following research questions were
addressed in this thesis using a murine model for asthma:
- Does the number of dendritic cells in the airways increase during a
secondary immune response? (Chapter 4)
- Is an intratracheal injection of antigen pulsed dendritic cells sufficient
to induce a secondary immune response in already sensitized mice?
(Chapter 5 en 6)
- Does depletion of dendritic cells in sensitized mice before and during
challenge inhibit the development of an eosinophilic airway
inflammation? (Chapter 5)
- Does the capacity of dendritic cells to provide CDS0/86 costimulation
contribute to the function of dendritic cells in the secondary immune
response? (Chapter 6)
- Do eosinophils play a role as antigen presenting cells during the
secondary immune response? (Chapter 7
Every smile matters:Oral health and orofacial pain in older people with dementia in UK care settings
Every smile matters:Oral health and orofacial pain in older people with dementia in UK care settings
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