2,844 research outputs found
Recent progress in mitochondria-targeted drug and drug-free agents for cancer therapy
The mitochondrion is a dynamic eukaryotic organelle that controls lethal and vital functions of the cell. Being a critical center of metabolic activities and involved in many diseases, mitochondria have been attracting attention as a potential target for therapeutics, especially for cancer treatment. Structural and functional differences between healthy and cancerous mitochondria, such as membrane potential, respiratory rate, energy production pathway, and gene mutations, could be employed for the design of selective targeting systems for cancer mitochondria. A number of mitochondria-targeting compounds, including mitochondria-directed conventional drugs, mitochondrial proteins/metabolism-inhibiting agents, and mitochondria-targeted photosensitizers, have been discussed. Recently, certain drug-free approaches have been introduced as an alternative to induce selective cancer mitochondria dysfunction, such as intramitochondrial aggregation, self-assembly, and biomineralization. In this review, we discuss the recent progress in mitochondria-targeted cancer therapy from the conventional approach of drug/cytotoxic agent conjugates to advanced drug-free approaches
The development and application of time resolved PIV at the University of Strathclyde
This paper describes the development of time resolved particle image velocimetry (PIV) within the Department of Mechanical Engineering at the University of Strathclyde. The Department's first PIV systems were developed on a limited budget and used existing and second hand equipment. The original technique which, employed 16mm high speed cinematography, is described. The introduction and development of low cost systems employing high speed digital video (HSDV) is discussed and, finally, the Department's new time resolved PIV system, supplied by Dantec Dynamics, is introduced. For each of the PIV systems that have been developed a critical analysis of their functionality is given and samples of the data that they have been produced are shown. Data are presented from systems such as de-rotated centrifugal impellers, air bubbles growing in columns of water, pulsatile jets and vortex shedding
Damping mechanism for the strongly renormalized -axis charge transport in high- cuprate superconductors
We analyze the -axis infrared reflectivity of
LaSrCuO single crystals. The plasma edge near 6 meV,
observed below , is due to Cooper-pair tunneling. This low value of the
plasma edge is consistent with the -axis plasma frequency () obtained
from LDA calculations ( eV) if we take into account that the
single-particle charge transport along the axis is strongly incoherent both
above and below . We find no evidence for a reduction of the -axis
scattering rate () below . Our investigation suggests
, which is exactly opposite to the clean limit.
VSGD.94.6.1Comment: 4 pages, figures on request. Revtex, version 2, Materials Science
Center Internal Report Number VSGD.94.6.
Berry's Phase in the Presence of a Dissipative Medium
We consider the spin 1/2 model coupled to a slowly varying magnetic field in
the presence of a weak damping represented by a Lindblad-form operators. We
show that Berry's geometrical phase remains unaltered by the two dissipation
mechanism considered. Dissipation effects are twofold: a shrinking in the
modulus of the Bloch's vector, which characterizes coherence loss and a time
dependent (dissipation related) precession angle. We show that the line
broadening of the Fourier transformation of the components of magnetization is
only due to the presence of dissipation.Comment: 19 pages, 2 figure
A macroscopic multifractal analysis of parabolic stochastic PDEs
It is generally argued that the solution to a stochastic PDE with
multiplicative noise---such as , where denotes
space-time white noise---routinely produces exceptionally-large peaks that are
"macroscopically multifractal." See, for example, Gibbon and Doering (2005),
Gibbon and Titi (2005), and Zimmermann et al (2000). A few years ago, we proved
that the spatial peaks of the solution to the mentioned stochastic PDE indeed
form a random multifractal in the macroscopic sense of Barlow and Taylor (1989;
1992). The main result of the present paper is a proof of a rigorous
formulation of the assertion that the spatio-temporal peaks of the solution
form infinitely-many different multifractals on infinitely-many different
scales, which we sometimes refer to as "stretch factors." A simpler, though
still complex, such structure is shown to also exist for the
constant-coefficient version of the said stochastic PDE.Comment: 41 page
Instantons of M(atrix) Theory in PP-Wave Background
M(atrix) theory in PP-wave background possesses a discrete set of classical
vacua, all of which preserves 16 supersymmetry and interpretable as collection
of giant gravitons. We find Euclidean instanton solutions that interpolate
between them, and analyze their properties. Supersymmetry prevents direct
mixing between different vacua but still allows effect of instanton to show up
in higher order effective interactions, such as analog of v^4 interaction of
flat space effective theory. An explicit construction of zero modes is
performed, and Goldstone zero modes, bosonic and fermionic, are identified. We
further generalize this to massive M(atrix) theory that includes fundamental
hypermultiplets, corresponding to insertion of longitudinal fivebranes in the
background. After a brief comparison to their counterpart in AdS\times S, we
close with a summary.Comment: 25 pages, LaTeX, references added, section 5 update
BPS Electromagnetic Waves on Giant Gravitons
We find new 1/8-BPS giant graviton solutions in , carrying
three angular momenta along , and investigate their properties.
Especially, we show that nonzero worldvolume gauge fields are admitted
preserving supersymmetry. These gauge field modes can be viewed as
electromagnetic waves along the compact D3 brane, whose Poynting vector
contributes to the BPS angular momenta. We also analyze the (nearly-)spherical
giant gravitons with worldvolume gauge fields in detail. Expressing the
in Hopf fibration ( fibred over ), the wave propagates along the
fiber.Comment: 25 pages, no figures, v2: references adde
Effect of magnetic and non-magnetic impurities on highly anisotropic superconductivity
We generalize Abrikosov-Gor'kov solution of the problem of weakly coupled
superconductor with impurities on the case of a multiband superconductor with
arbitrary interband order parameter anisotropy, including interband sign
reversal of the order parameter. The solution is given in terms of the
effective (renormalized) coupling matrix and describes not only
suppression but also renormalization of the superconducting gap basically at
all temperatures. In many limiting cases we find analytical solutions for the
critical temperature suppression. We illustrate our results by numerical
calculations for two-band model systems.Comment: 18 pages (12pt) RevTeX, 4 postscript figure
Electrically pumped quantum post vertical cavity surface emitting lasers
Quantum Matter and Optic
Carbon Nanotubes as Nanoelectromechanical Systems
We theoretically study the interplay between electrical and mechanical
properties of suspended, doubly clamped carbon nanotubes in which charging
effects dominate. In this geometry, the capacitance between the nanotube and
the gate(s) depends on the distance between them. This dependence modifies the
usual Coulomb models and we show that it needs to be incorporated to capture
the physics of the problem correctly. We find that the tube position changes in
discrete steps every time an electron tunnels onto it. Edges of Coulomb
diamonds acquire a (small) curvature. We also show that bistability in the tube
position occurs and that tunneling of an electron onto the tube drastically
modifies the quantized eigenmodes of the tube. Experimental verification of
these predictions is possible in suspended tubes of sub-micron length.Comment: 8 pages, 5 eps figures included. Major changes; new material adde
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