2,465 research outputs found
Born--Oppenheimer decomposition for quantum fields on quantum spacetimes
Quantum Field Theory on Curved Spacetime (QFT on CS) is a well established
theoretical framework which intuitively should be a an extremely effective
description of the quantum nature of matter when propagating on a given
background spacetime. If one wants to take care of backreaction effects, then a
theory of quantum gravity is needed. It is now widely believed that such a
theory should be formulated in a non-perturbative and therefore background
independent fashion. Hence, it is a priori a puzzle how a background dependent
QFT on CS should emerge as a semiclassical limit out of a background
independent quantum gravity theory. In this article we point out that the
Born-Oppenheimer decomposition (BOD) of the Hilbert space is ideally suited in
order to establish such a link, provided that the Hilbert space representation
of the gravitational field algebra satisfies an important condition. If the
condition is satisfied, then the framework of QFT on CS can be, in a certain
sense, embedded into a theory of quantum gravity. The unique representation of
the holonomy-flux algebra underlying Loop Quantum Gravity (LQG) violates that
condition. While it is conceivable that the condition on the representation can
be relaxed, for convenience in this article we consider a new classical
gravitational field algebra and a Hilbert space representation of its
restriction to an algebraic graph for which the condition is satisfied. An
important question that remains and for which we have only partial answers is
how to construct eigenstates of the full gravity-matter Hamiltonian whose BOD
is confined to a small neighbourhood of a physically interesting vacuum
spacetime.Comment: 38 pages, 2 figure
THERAPEUTIC DEVELOPMENT FOR CYSTIC FIBROSIS
This thesis considers the aspects of therapeutics development for Cystic Fibrosis (CF). The studies are directed at the development of a new therapeutic outcome measurement for evaluating the performance of CF medications. This imaging-based outcome measures the absorption of a small-molecular radiopharmaceutical, Diethylene triamine pentaacetic acid (DTPA) from the airways as a surrogate measure of liquid absorption. Airway liquid hyper-absorption is a key aspect of CF lung disease that would be expected to correct rapidly after administration of a successful therapy. In vivo pilot studies of this technique have been previously performed at our center [1]. Here we report the results of in vitro studies performed to better define the mechanism underpinning our method and define its utility and limitations
Hamiltonian Theory: Dynamics
This chapter focuses on the status of the implementation of the dynamics in
the canonical version of Loop Quantum Gravity (LQG). Concretely this means to
provide a mathematical meaning of the quantum Einstein equations, sometimes
called Wheeler-DeWitt equations, to give a physical interpretation and Hilbert
space structure to its solutions and to construct a representation of the
algebra of observables including a physical Hamiltonian. This is a structural
overview intentionally skipping technical details.Comment: 52 pages. This is a preprint of a chapter to appear in the "Handbook
of Quantum Gravity", edited by Cosimo Bambi, Leonardo Modesto and Ilya
Shapiro, 2023, Springer, reproduced with permission of Springe
Lavender oil-potent anxiolytic properties via modulating voltage dependent calcium channels
Recent clinical data support the clinical use of oral lavender oil in patients suffering from subsyndromal anxiety. We identified the molecular mechanism of action that will alter the perception of lavender oil as a nonspecific ingredient of aromatherapy to a potent anxiolytic inhibiting voltage dependent calcium channels (VOCCs) as highly selective drug target. In contrast to previous publications where exorbitant high concentrations were used, the effects of lavender oil in behavioral, biochemical, and electrophysiological experiments were investigated in physiological concentrations in the nanomolar range, which correlate to a single dosage of 80 mg/d in humans that was used in clinical trials. We show for the first time that lavender oil bears some similarities with the established anxiolytic pregabalin. Lavender oil inhibits VOCCs in synaptosomes, primary hippocampal neurons and stably overexpressing cell lines in the same range such as pregabalin. Interestingly, Silexan does not primarily bind to P/Q type calcium channels such as pregabalin and does not interact with the binding site of pregabalin, the α2δ subunit of VOCCs. Lavender oil reduces non-selectively the calcium influx through several different types of VOCCs such as the N-type, P/Q-type and T-type VOCCs. In the hippocampus, one brain region important for anxiety disorders, we show that inhibition by lavender oil is mainly mediated via N-type and P/Q-type VOCCs. Taken together, we provide a pharmacological and molecular rationale for the clinical use of the oral application of lavender oil in patients suffering from anxiety
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