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Age-related changes in blood-brain barrier integrity in C57BL/6J mice
The blood-brain barrier (BBB) is formed by the endothelial cells of the brain microvasculature, which control the molecular traffic between the blood and brain to maintain the neural microenvironment
Superconducting Vortex Lattices for Ultracold Atoms
We propose and analyze a nanoengineered vortex array in a thin-film type-II
superconductor as a magnetic lattice for ultracold atoms. This proposal
addresses several of the key questions in the development of atomic quantum
simulators. By trapping atoms close to the surface, tools of nanofabrication
and structuring of lattices on the scale of few tens of nanometers become
available with a corresponding benefit in energy scales and temperature
requirements. This can be combined with the possibility of magnetic single site
addressing and manipulation together with a favorable scaling of
superconducting surface-induced decoherence.Comment: Published Version. Manuscript: 5 pages, 3 figures. Supplementary
Information: 11 pages, 7 figure
Magnetic, electronic and vibrational properties of metal and fluorinated metal phthalocyanines
The magnetic and electronic properties of metal phthalocyanines (MPc) and
fluorinated metal phthalocyanines (FMPc) are studied by means of spin
density functional theory (SDFT). Several metals (M) such as Ca, all first
d-row transition metals and Ag are investigated. By considering different open
shell transition metals it is possible to tune the electronic properties of
MPc, in particular the electronic molecular gap and total magnetic moment.
Besides assigning the structural and electronic properties of MPc and
FMPc, the vibrational modes analysis of the ScPc\textendash ZnPc series
have been studied and correlated to experimental measurements when available.Comment: 28 pages (preprint style), several figure
Global aspects of gravitomagnetism
We consider global properties of gravitomagnetism by investigating the
gravitomagnetic field of a rotating cosmic string. We show that although the
gravitomagnetic field produced by such a configuration of matter vanishes
locally, it can be detected globally. In this context we discuss the
gravitational analogue of the Aharonov-Bohm effect.Comment: 10 pages - Typeset using REVTE
Large Quantum Superpositions and Interference of Massive Nanometer-Sized Objects
We propose a method to prepare and verify spatial quantum superpositions of a
nanometer-sized object separated by distances of the order of its size. This
method provides unprecedented bounds for objective collapse models of the wave
function by merging techniques and insights from cavity quantum optomechanics
and matter wave interferometry. An analysis and simulation of the experiment is
performed taking into account standard sources of decoherence. We provide an
operational parameter regime using present day and planned technology.Comment: 4 pages, 2 figures, to appear in PR
The embedding of the spacetime in five dimensions: an extension of Campbell-Magaard theorem
We extend Campbell-Magaard embedding theorem by proving that any
n-dimensional semi-Riemannian manifold can be locally embedded in an
(n+1)-dimensional Einstein space. We work out some examples of application of
the theorem and discuss its relevance in the context of modern
higher-dimensional spacetime theories.Comment: 22pages, Revte
Uptake and cytotoxicity of citrate-coated gold nanospheres : comparative studies on human endothelial and epithelial cells
The use of gold nanoparticles (AuNPs) for diagnostic applications and for drug and gene-delivery is currently under intensive investigation. For such applications, biocompatibility and the absence of cytotoxicity of AuNPs is essential. Although generally considered as highly biocompatible, previous in vitro studies have shown that cytotoxicity of AuNPs in certain human epithelial cells was observed. In particular, the degree of purification of AuNPs (presence of sodium citrate residues on the particles) was shown to affect the proliferation and induce cytotoxicity in these cells. To expand these studies, we have examined if the effects are related to nanoparticle size (10, 11ânm, 25ânm), to the presence of sodium citrate on the particles' surface or they are due to a varying degree of internalization of the AuNPs. Since two cell types are present in the major barriers to the outside in the human body, we have also included endothelial cells from the vasculature and blood brain barrier.
Results
Transmission electron microscopy demonstrates that the internalized gold nanoparticles are located within vesicles. Increased cytotoxicity was observed after exposure to AuNPs and was found to be concentration-dependent. In addition, cell viability and the proliferation of both endothelial cells decreased after exposure to gold nanoparticles, especially at high concentrations. Moreover, in contrast to the size of the particles (10ânm, 11ânm, 25ânm), the presence of sodium citrate on the nanoparticle surface appeared to enhance these effects. The effects on microvascular endothelial cells from blood vessels were slightly enhanced compared to the effects on brain-derived endothelial cells. A quantification of AuNPs within cells by ICP-AES showed that epithelial cells internalized a higher quantity of AuNPs compared to endothelial cells and that the quantity of uptake is not correlated with the amount of sodium citrate on the nanoparticlesâ surface.
Conclusions
In conclusion the higher amount of citrate on the particle surface resulted in a higher impairment of cell viability, but did not enhance or reduce the uptake behavior in endothelial or epithelial cells. In addition, epithelial and endothelial cells exhibited different uptake behaviors for citrate-stabilized gold nanoparticles, which might be related to different interactions occurring at the nanoparticle-cell-surface interface. The different uptake in epithelial cells might explain the higher reduction of proliferation of these cells after exposure to AuNPs treatment although more detailed investigations are necessary to determine subcellular events. Nevertheless an extrinsic effect of sodium-citrate stabilized particles could not be excluded. Thus, the amount of sodium citrate should be reduced to a level on which the stability of the particles and the safety for biomedical applications are guaranteed
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