145,723 research outputs found
Particle deposition onto a flat plate with various slopes
In this work, a numerical simulation of the deposition of small suspended particles onto a flat plate with various degrees of inclination is performed. The particle deposition rates are obtained for various Reynolds and Rayleigh number groups
Safety of herbal medicinal products: Echinacea and selected alkylamides do not induce CYP3A4 mRNA expression
Copyright © 2011 Maryam Modarai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.A major safety concern with the use of herbal medicinal products (HMP) is their interactions with conventional medicines, which are often mediated via the cytochrome P450 (CYP) system. Echinacea is a widely used over-the-counter HMP, with proven immunomodulatory properties. Its increasing use makes research into its safety an urgent concern. Previously, we showed that Echinacea extracts and its alkylamides (thought to be important for Echinacea's immunomodulatory activity) mildly inhibit the enzymatic activity of the main drug metabolising CYP isoforms, but to this date, there is insufficient work on its ability to alter CYP expression levels. We now report for the first time the effect of a commercial Echinacea extract (Echinaforce) and four Echinacea alkylamides on the transcription of the major drug metabolizing enzyme CYP3A4. HepG2 cells were exposed for 96 h to clinically relevant concentrations of Echinaforce (22, 11.6 and 1.16g mL-1) or the alkylamides (1.62 and 44 nM). CYP3A4 mRNA levels were quantified using real-time reverse transcription polymerase chain reaction (RT-PCR). Neither Echinaforce nor the alkylamides produced any significant changes in the steady-state CYP3A4 mRNA levels, under these conditions. In contrast, treatment with 50M rifampicin resulted in a 3.8-fold up-regulation over the vehicle control. We conclude that Echinaforce is unlikely to affect CYP3A4 transcriptional levels, even at concentrations which can inhibit the enzymatic activity of CYP3A4. Overall, our data provides further evidence for the lack of interactions between Echinacea and conventional drugs.Bioforce, Switzerland and the Maplethorpe Trust (University of London)
Temporal evolution of the "thermal" and "superthermal" income classes in the USA during 1983-2001
Personal income distribution in the USA has a well-defined two-class
structure. The majority of population (97-99%) belongs to the lower class
characterized by the exponential Boltzmann-Gibbs ("thermal") distribution,
whereas the upper class (1-3% of population) has a Pareto power-law
("superthermal") distribution. By analyzing income data for 1983-2001, we show
that the "thermal" part is stationary in time, save for a gradual increase of
the effective temperature, whereas the "superthermal" tail swells and shrinks
following the stock market. We discuss the concept of equilibrium inequality in
a society, based on the principle of maximal entropy, and quantitatively show
that it applies to the majority of population.Comment: v.3: 7 pages, 5 figures, EPL style, more references adde
Experimental Monte Carlo Quantum Process Certification
Experimental implementations of quantum information processing have now
reached a level of sophistication where quantum process tomography is
impractical. The number of experimental settings as well as the computational
cost of the data post-processing now translates to days of effort to
characterize even experiments with as few as 8 qubits. Recently a more
practical approach to determine the fidelity of an experimental quantum process
has been proposed, where the experimental data is compared directly to an ideal
process using Monte Carlo sampling. Here we present an experimental
implementation of this scheme in a circuit quantum electrodynamics setup to
determine the fidelity of two qubit gates, such as the cphase and the cnot
gate, and three qubit gates, such as the Toffoli gate and two sequential cphase
gates
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