8,980 research outputs found
Potential P-Glycoprotein-Mediated Drug-Drug Interactions of Antimalarial Agents in Caco-2 cells
Antimalarials are widely used in African and Southeast Asian countries, where they are combined with other drugs for the treatment of concurrent ailments. The potential for P-glycoprotein (P-gp)-mediated drug-drug interactions (DDIs) between antimalarials and P-gp substrates was examined using a Caco-2 cell-based model. Selected antimalarials were initially screened for their interaction with P-gp based on the inhibition of rhodamine-123 (Rho-123) transport in Caco-2 cells. Verapamil (100 mM) and quinidine (1 mM) were used as positive inhibition controls. Lumefantrine, amodiaquin, and artesunate all showed blockade of Rho-123 transport. Subsequently, the inhibitory effect of these antimalarials on the bi-directional passage of digoxin (DIG) was examined. All of the drugs decreased basal-toapical (B-A) P-gp-mediated DIG transport at concentrations of 100 mM and 1 mM. These concentrations may reflect therapeutic doses for amodiaquin and artesunate. Therefore, clinically relevant DDIs may occur between certain antimalarials and P-gp substrates in general
The inner automorphism 3-group of a strict 2-group
Any group gives rise to a 2-group of inner automorphisms,
. It is an old result by Segal that the nerve of this is the
universal -bundle. We discuss that, similarly, for every 2-group
there is a 3-group and a slightly smaller 3-group
of inner automorphisms. We describe these for
any strict 2-group, discuss how can be
understood as arising from the mapping cone of the identity on and
show that its underlying 2-groupoid structure fits into a short exact sequence
.
As a consequence, encodes the properties of the
universal 2-bundle.Comment: references added, relation to simplicial constructions expanded,
version to appear in JHR
Spin Calogero models associated with Riemannian symmetric spaces of negative curvature
The Hamiltonian symmetry reduction of the geodesics system on a symmetric
space of negative curvature by the maximal compact subgroup of the isometry
group is investigated at an arbitrary value of the momentum map. Restricting to
regular elements in the configuration space, the reduction generically yields a
spin Calogero model with hyperbolic interaction potentials defined by the root
system of the symmetric space. These models come equipped with Lax pairs and
many constants of motion, and can be integrated by the projection method. The
special values of the momentum map leading to spinless Calogero models are
classified under some conditions, explaining why the models with two
independent coupling constants are associated with as found by Olshanetsky and Perelomov. In the zero curvature limit our
models reproduce rational spin Calogero models studied previously and similar
models correspond to other (affine) symmetric spaces, too. The construction
works at the quantized level as well.Comment: 26 pages, v3: final version with a remark added after equation (5.3
Derivations of the trigonometric BC(n) Sutherland model by quantum Hamiltonian reduction
The BC(n) Sutherland Hamiltonian with coupling constants parametrized by
three arbitrary integers is derived by reductions of the Laplace operator of
the group U(N). The reductions are obtained by applying the Laplace operator on
spaces of certain vector valued functions equivariant under suitable symmetric
subgroups of U(N)\times U(N). Three different reduction schemes are considered,
the simplest one being the compact real form of the reduction of the Laplacian
of GL(2n,C) to the complex BC(n) Sutherland Hamiltonian previously studied by
Oblomkov.Comment: 30 pages, LateX; v2: final version with minor stylistic modification
The classification of substance and behavioural addictions: A preliminary investigation
The term addiction has been used to refer to impaired control over substance use for several centuries however recently there has been a shift toward using this term in the context of non-substance use disorders, such as pathological gambling. A preliminary investigation was conducted in an attempt to clarify the most appropriate classification of 'behavioural addictions'. Participants with alcohol dependence (AD, n = 24), pathological gambling (PG, n = 20) and compulsive buying disorder (CBD, n = 14) completed an Addictive Disorder Questionnaire (ADQ); the Symptom Checklist 90 Revised (SCL-90R); Barratt Impulsivity Scale II; and substance specific adaptations of the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). Although the AD group reported more severe addiction symptoms and had higher levels of depression and anxiety, there were broad similarities across the three disorders in relation to cravings, dyscontrol, impulsivity and obsessions. Despite the small sample size and the different recruitment strategies used across the groups, the findings from this preliminary study provide support for broadening addiction diagnostic definitions to include non-substance related disorders which in turn may contribute to the development of more efficacious treatments
Un-reduction
This paper provides a full geometric development of a new technique called
un-reduction, for dealing with dynamics and optimal control problems posed on
spaces that are unwieldy for numerical implementation. The technique, which was
originally concieved for an application to image dynamics, uses Lagrangian
reduction by symmetry in reverse. A deeper understanding of un-reduction leads
to new developments in image matching which serve to illustrate the
mathematical power of the technique.Comment: 25 pages, revised versio
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