128 research outputs found
Monetary Policy in a Small Open Economy Model: A DSGE-VAR Approach for Switzerland
We study the transmission of monetary shocks and monetary policy with a behavioral model, corrected for potential misspecification using the DSGE-VAR framework elaborated by DelNegro and Schorfheide (2004). In particular, we investigate if the central bank should react to movements in the nominal exchange rate. We contribute to the empirical literature as we use Swiss data, which is very rarely used in that context.
External control strategies for self-propelled particles: optimizing navigational efficiency in the presence of limited resources
We experimentally and numerically study the dependence of different
navigation strategies regarding the effectivity of an active particle to reach
a predefined target area. As the only control parameter, we vary the particle's
propulsion velocity depending on its position and orientation relative to the
target site. By introducing different figures of merit, e.g. the time to target
or the total consumed propulsion energy, we are able to quantify and compare
the efficiency of different strategies. Our results suggest, that each strategy
to navigate towards a target, has its strengths and weaknesses and none of them
outperforms the other in all regards. Accordingly, the choice of an ideal
navigation strategy will strongly depend on the specific conditions and the
figure of merit which should be optimized
Efficient Radio Frequency filters for space constrained cryogenic set-ups
Noise filtering is an essential part for measurement of quantum phenomena at
extremely low temperatures. Here, we present the design of a filter which can
be installed in space constrained cryogenic environment containing a large
number of signal carrying lines. Our filters have a -3db point of 65kHz and its
performance at GHz frequencies are comparable to the best available RF filters.Comment: 9 pages, 4 figures, The capacitor reference in the first version was
wrong and has been changed to the right on
Theoretical, numerical, and experimental study of a flying qubit electronic interferometer
We discuss an electronic interferometer recently measured by Yamamoto et al.
This "flying quantum bit" experiment showed quantum oscillations between
electronic trajectories of two tunnel-coupled wires connected via an
Aharanov-Bohm ring. We present a simple scattering model as well as a numerical
microscopic model to describe this experiment. In addition, we present new
experimental data to which we confront our numerical results. While our
analytical model provides basic concepts for designing the flying qubit device,
we find that our numerical simulations allow to reproduce detailed features of
the transport measurements such as in-phase and anti-phase oscillations of the
two output currents as well as a smooth phase shift when sweeping a side gate.
Furthermore, we find remarkable resemblance for the magneto conductance
oscillations in both conductance and visibility between simulations and
experiments within a specific parameter range.Comment: 10 pages, 13 figure
Administration of a VEGFR‑2-specific MRI contrast agent to assess orthodontic tooth movement
Purpose
It is thought that orthodontic forces initially reduce periodontal blood flow during orthodontic tooth movement (OTM) via tissue compression with cells responding to concomitant oxygen deprivation with expression of vascular endothelial growth factor (VEGF) triggering angiogenesis via binding to its receptor VEGFR‑2. To test this hypothesis, we performed a pilot study to establish a protocol for molecular magnetic resonance imaging (MRI) of rat jaws administering a VEGFR-2-specific contrast agent.
Methods
Mesial OTM of a first upper left rat molar was initiated in one male Fischer 344 rat 4 days prior to MRI by insertion of an elastic band between the first and second upper molars with the contralateral side left untreated (internal control). T1-weighted MRI sequences including dynamic contrast-enhanced MRI (DCE-MRI) were recorded before and after administration of a molecular VEGFR‑2 MRI marker with a 7 T MRI dedicated for small animal use.
Results
After injection of anti-VEGFR2-albumin-gadolinium-DTPA, volume enhancement on T1-weighted images was increased at the OTM side distally of the moved first upper molar (M1) compared to the control side, whereas the T1 relaxation time was reduced on the OTM side. DCE-MRI resulted in an increased area under the curve (AUC), whereas time-to-peak (TTP) and washout rate were reduced during OTM distally of the moved M1 compared to the contralateral side.
Conclusions
OTM resulted in uptake of the VEGFR-2-specific MRI contrast agent in tension areas of the periodontal ligament. The imaging protocol presented here is useful for the assessment of VEGFR‑2 expression in tension areas of the periodontal ligament in vivo
Comprehensive phenotyping revealed transient startle response reduction and histopathological gadolinium localization to perineuronal nets after gadodiamide administration in rats
Gadolinium based contrast agents (GBCAs) are widely used in clinical MRI since the mid-1980s. Recently, concerns have been raised that trace amounts of Gadolinium (Gd), detected in brains even long time after GBCA application, may cause yet unrecognized clinical consequences. We therefore assessed the behavioral phenotype, neuro-histopathology, and Gd localization after repeated administration of linear (gadodiamide) or macrocyclic (gadobutrol) GBCA in rats. While most behavioral tests revealed no difference between treatment groups, we observed a transient and reversible decrease of the startle reflex after gadodiamide application. Residual Gd in the lateral cerebellar nucleus was neither associated with a general gene expression pathway deregulation nor with neuronal cell loss, but in gadodiamide-treated rats Gd was associated with the perineuronal net protein aggrecan and segregated to high molecular weight fractions. Our behavioral finding together with Gd distribution and speciation support a substance class difference for Gd presence in the brain after GBCA application
Combinatorial Drug Treatments Reveal Promising Anticytomegaloviral Profiles for Clinically Relevant Pharmaceutical Kinase Inhibitors (PKIs)
Human cytomegalovirus (HCMV) is a human pathogenic herpesvirus associated with a variety of clinical symptoms. Current antiviral therapy is not always effective, so that improved drug classes and drug-targeting strategies are needed. Particularly host-directed antivirals, including pharmaceutical kinase inhibitors (PKIs), may help to overcome problems of drug resistance. Here, we focused on utilizing a selection of clinically relevant PKIs and determined their anticytomegaloviral efficacies. Particularly, PKIs directed to host or viral cyclin-dependent kinases, i.e., abemaciclib, LDC4297 and maribavir, exerted promising profiles against human and murine cytomegaloviruses. The anti-HCMV in vitro activity of the approved anti-cancer drug abemaciclib was confirmed in vivo using our luciferase-based murine cytomegalovirus (MCMV) animal model in immunocompetent mice. To assess drug combinations, we applied the Bliss independence checkerboard and Loewe additivity fixed-dose assays in parallel. Results revealed that (i) both affirmative approaches provided valuable information on anti-CMV drug efficacies and interactions, (ii) the analyzed combinations comprised additive, synergistic or antagonistic drug interactions consistent with the drugs’ antiviral mode-of-action, (iii) the selected PKIs, especially LDC4297, showed promising inhibitory profiles, not only against HCMV but also other α-, β- and γ-herpesviruses, and specifically, (iv) the combination treatment with LDC4297 and maribavir revealed a strong synergism against HCMV, which might open doors towards novel clinical options in the near future. Taken together, this study highlights the potential of therapeutic drug combinations of current developmental/preclinical PKIs
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