2,294 research outputs found
Anti-malarial ozonides OZ439 and OZ609 tested at clinically relevant compound exposure parameters in a novel ring-stage survival assay
BACKGROUND: Drug efficacy against kelch 13 mutant malaria parasites can be determined in vitro with the ring-stage survival assay (RSA). The conventional assay protocol reflects the exposure profile of dihydroartemisinin. METHODS: Taking into account that other anti-malarial peroxides, such as the synthetic ozonides OZ439 (artefenomel) and OZ609, have different pharmacokinetics, the RSA was adjusted to the concentration-time profile of these ozonides in humans and a novel, semi-automated readout was introduced. RESULTS: When tested at clinically relevant parameters, it was shown that OZ439 and OZ609 are active against the Plasmodium falciparum clinical isolate Cam3.I(R539T). CONCLUSION: If the in vitro RSA does indeed predict the potency of compounds against parasites with increased tolerance to artemisinin and its derivatives, then the herein presented data suggest that following drug-pulses of at least 48 h, OZ439 and OZ609 will be highly potent against kelch 13 mutant isolates, such as P. falciparum Cam3.I(R539T)
Vanishing Fe 3d orbital moments in single-crystalline magnetite
We show detailed magnetic absorption spectroscopy results of an in situ
cleaved high quality single crystal of magnetite. In addition the experimental
setup was carefully optimized to reduce drift, self absorption, and offset
phenomena as far as possible. In strong contradiction to recently published
data, our observed orbital moments are nearly vanishing and the spin moments
are quite close to the integer values proposed by theory. This very important
issue supports the half metallic full spin polarized picture of magnetite.Comment: 7 pages, 4 figure
Calculation of electrostatic fields using quasi-Green's functions: application to the hybrid Penning trap.
Penning traps offer unique possibilities for storing, manipulating and investigating charged particles with high sensitivity and accuracy. The widespread applications of Penning traps in physics and chemistry comprise e.g. mass spectrometry, laser spectroscopy, measurements of electronic and nuclear magnetic moments, chemical sample analysis and reaction studies. We have developed a method, based on the Green's function approach, which allows for the analytical calculation of the electrostatic properties of a Penning trap with arbitrary electrodes. The ansatz features an extension of Dirichlet's problem to nontrivial geometries and leads to an analytical solution of the Laplace equation. As an example we discuss the toroidal hybrid Penning trap designed for our planned measurements of the magnetic moment of the (anti)proton. As in the case of cylindrical Penning traps, it is possible to optimize the properties of the electric trapping fields, which is mandatory for high-precision experiments with single charged particles. Of particular interest are the anharmonicity compensation, orthogonality and optimum adjustment of frequency shifts by the continuous SternGerlach effect in a quantum jump spectrometer. The mathematical formalism developed goes beyond the mere design of novel Penning traps and has potential applications in other fields of physics and engineering
Automation concepts and gripping solutions for bonding with reactive multilayer systems
Reactive multilayer systems (RMS) represent an innovative heat source for the establishment of solder joints. They offer fast bonding processes that introduce very little thermal input and internal stress on the bonded parts. The current application process of RMS is predominantly manual labor. There are a couple of challenges to be overcome to automate this process, a requirement for its introduction into industrial production. In this paper we evaluate the requirements for an automated joining process with RMS and devise a concept of a modular assembly system for different product structures. Furthermore we show our results in gently and reliably gripping and handling of RMS.Federal Ministry of Economic and Technology (BMWi)InnoJoin GmbH & Co. KG, Breme
Towards the theory of ferrimagnetism
Two-sublattice ferrimagnet, with spin- operators at the
sublattice site and spin- operators at the sublattice
site, is considered. The magnon of the system, the transversal fluctuation
of the total magnetization, is a complicate mixture of the transversal
fluctuations of the sublattice and spins. As a result, the magnons'
fluctuations suppress in a different way the magnetic orders of the and
sublattices and one obtains two phases. At low temperature the
magnetic orders of the and spins contribute to the magnetization of the
system, while at the high temperature , the magnetic order of the
spins with a weaker intra-sublattice exchange is suppressed by magnon
fluctuations, and only the spins with stronger intra-sublattice exchange has
non-zero spontaneous magnetization. The transition is a transition
between two spin-ordered phases in contrast to the transition from spin-ordered
state to disordered state (-transition). There is no additional symmetry
breaking, and the Goldstone boson has a ferromagnetic dispersion in both
phases. A modified spin-wave theory is developed to describe the two phases.
All known Neel's anomalous curves are reproduced, in particular that
with "compensation point". The theoretical curves are compared with
experimental ones for sulpho-spinel and rare earth iron
garnets.Comment: 9 pages, 8 figure
On The 5D Extra-Force according to Basini-Capozziello-Leon Formalism and five important features: Kar-Sinha Gravitational Bending of Light, Chung-Freese Superluminal Behaviour, Maartens-Clarkson Black Strings, Experimental measures of Extra Dimensions on board International Space Station(ISS) and the existence of the Particle due to a Higher Dimensional spacetime
We use the Conformal Metric as described in Kar-Sinha work on Gravitational
Bending of Light in a 5D Spacetime to recompute the equations of the 5D Force
in Basini-Capozziello-Leon Formalism and we arrive at a result that possesses
some advantages. The equations of the Extra Force as proposed by Leon are now
more elegant in Conformal Formalism and many algebraic terms can be simplified
or even suppressed. Also we recompute the Kar-Sinha Gravitational Bending of
Light affected by the presence of the Extra Dimension and analyze the
Superluminal Chung-Freese Features of this Formalism describing the advantages
of the Chung-Freese BraneWorld when compared to other Superluminal spacetime
metrics(eg:Warp Drive) and we describe why the Extra Dimension is invisible and
how the Extra Dimension could be made visible at least in theory.We also
examine the Maartens-Clarkson Black Holes in 5D(Black Strings) coupled to
massive Kaluza-Klein graviton modes predicted by Extra Dimensions theories and
we study experimental detection of Extra Dimensions on-board LIGO and LISA
Space Telescopes.We also propose the use of International Space Station(ISS) to
measure the additional terms(resulting from the presence of Extra Dimensions)
in the Kar-Sinha Gravitational Bending of Light in Outer Space to verify if we
really lives in a Higher Dimensional Spacetime.Also we demonstrate that
Particle can only exists if the 5D spacetime exists.Comment: Withdrawn: author no longer wishes to post work on arXi
Results on Plasma Focusing of High Energy Density Electron and Positron Beams
We present results from the SLAC E-150 experiment on plasma focusing of high
energy density electron and, for the first time, positron beams. We also
discuss measurements on plasma lens-induced synchrotron radiation, longitudinal
dynamics of plasma focusing, and laser- and beam-plasma interactions.Comment: LINAC 2000 paper No. THC13, Monterey, CA. Aug.21-25,2000, 3 pages, 2
figure
Displacement field and elastic constants in non-ideal crystals
In this work a periodic crystal with point defects is described in the
framework of linear response theory for broken symmetry states using
correlation functions and Zwanzig-Mori equations. The main results are
microscopic expressions for the elastic constants and for the coarse-grained
density, point-defect density, and displacement field, which are valid in real
crystals, where vacancies and interstitials are present. The coarse-grained
density field differs from the small wave vector limit of the microscopic
density. In the long wavelength limit, we recover the phenomenological
description of elasticity theory including the defect density.Comment: Phys Rev. B, in print (2010
Influence of the 6^1S_0-6^3P_1 Resonance on Continuous Lyman-alpha Generation in Mercury
Continuous coherent radiation in the vacuum-ultraviolet at 122 nm
(Lyman-alpha) can be generated using sum-frequency mixing of three fundamental
laser beams in mercury vapour. One of the fundamental beams is at 254 nm
wavelength, which is close to the 6^1S_0-6^3P_1 resonance in mercury.
Experiments have been performed to investigate the effect of this one-photon
resonance on phasematching, absorption and the nonlinear yield. The efficiency
of continuous Lyman-alpha generation has been improved by a factor of 4.5.Comment: 8 pages, 7 figure
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