964 research outputs found
Critical holes in undercooled wetting layers
The profile of a critical hole in an undercooled wetting layer is determined
by the saddle-point equation of a standard interface Hamiltonian supported by
convenient boundary conditions. It is shown that this saddle-point equation can
be mapped onto an autonomous dynamical system in a three-dimensional phase
space. The corresponding flux has a polynomial form and in general displays
four fixed points, each with different stability properties. On the basis of
this picture we derive the thermodynamic behaviour of critical holes in three
different nucleation regimes of the phase diagram.Comment: 18 pages, LaTeX, 6 figures Postscript, submitted to J. Phys.
Identifizierung VHL-assoziierter Veränderungen im klarzelligen Nierenzellkarzinom: Anwendung von kombinierten Genom- und Expressionsanalysen
Zusammenfassung: Das sporadische Nierenzellkarzinom (NZK) ist ein heterogener solider Tumor, der traditionell basierend auf morphologischen Kriterien in weitere Subtypen unterteilt wird. In den letzten Jahren konnten unter Anwendung molekularer Hochdurchsatzanalysen genetische, transkriptionelle und translationale Alterationen identifiziert werden. Diese Marker eignen sich zum einen für die molekulare Klassifizierung des NZK und haben zum anderen prognostische Wertigkeit. Die isolierte Betrachtung genetischer, transkriptioneller und translationaler Veränderungen verhindert jedoch ein tieferes Verständnis für die komplexen Vorgänge der Karzinogenese. Wir fassen hier aktuelle Forschungsergebnisse zur molekularen Charakterisierung des NZK zusammen und stellen ein systembiologisches Konzept zur Identifizierung neuer Tumormarker vor. Diese könnten zukünftig Einsatz in der Diagnostik und Therapie des sporadischen NZK finde
Immunophenotyping without antibodies: New perspectives for lymphoma characterization
Aims: Accurate classification of haematological malignancies is a prerequisite for their correct diagnosis, prognosis and therapy. Clear classification of lymphomas is often hindered by the limited number of available cell surface protein markers that are suitable for immunophenotyping. A systematic and quantitative analysis of cell surface proteins is thus required to identify new protein markers on lymphoma subtypes in an unbiased and discovery-driven approach. Methods: Nine Hodgkin and non-Hodgkin B cell lines of diffuse large cell type and mediastinal type were investigated by cell surface capture (CSC) technology, a mass spectrometry-based method to identify cell surface glycoproteins. Selected proteins are verified by antibody-based methods, including flow cytometry and immunohistochemistry on cell line arrays. Results: A total of 747 predicted transmembrane proteins were identified from all cell lines, including 142 CD (cluster of differentiation) annotated proteins. A group of differentially expressed cell surface glycoproteins between Hodgkin and non-Hodgkin B cell lines was revealed via quantitative CSC technology. In addition to classical and expected CD molecules such as CD20 and CD30, less frequently expressed molecules such as CD2 on Hodgkin lymphoma (HL) cell lines were identified by CSC and verified by immunohistochemistry in cell lines and primary lymphoma tissue. A panel of CSC-identified differentiation glycoprotein candidates is currently under investigation on tissue microarrays (TMAs) from patient sample
Depinning in a Random Medium
We develop a renormalized continuum field theory for a directed polymer
interacting with a random medium and a single extended defect. The
renormalization group is based on the operator algebra of the pinning
potential; it has novel features due to the breakdown of hyperscaling in a
random system. There is a second-order transition between a localized and a
delocalized phase of the polymer; we obtain analytic results on its critical
pinning strength and scaling exponents. Our results are directly related to
spatially inhomogeneous Kardar-Parisi-Zhang surface growth.Comment: 11 pages (latex) with one figure (now printable, no other changes
Facet Formation in the Negative Quenched Kardar-Parisi-Zhang Equation
The quenched Kardar-Parisi-Zhang (QKPZ) equation with negative non-linear
term shows a first order pinning-depinning (PD) transition as the driving force
is varied. We study the substrate-tilt dependence of the dynamic transition
properties in 1+1 dimensions. At the PD transition, the pinned surfaces form a
facet with a characteristic slope as long as the substrate-tilt is
less than . When , the transition is discontinuous and the critical
value of the driving force is independent of , while the transition
is continuous and increases with when . We explain these
features from a pinning mechanism involving a localized pinning center and the
self-organized facet formation.Comment: 4 pages, source TeX file and 7 PS figures are tarred and compressed
via uufile
One-Bead Microrheology with Rotating Particles
We lay the theoretical basis for one-bead microrheology with rotating
particles, i.e, a method where colloids are used to probe the mechanical
properties of viscoelastic media. Based on a two-fluid model, we calculate the
compliance and discuss it for two cases. We first assume that the elastic and
fluid component exhibit both stick boundary conditions at the particle surface.
Then, the compliance fulfills a generalized Stokes law with a complex shear
modulus whose validity is only limited by inertial effects, in contrast to
translational motion. Secondly, we find that the validity of the Stokes regime
is reduced when the elastic network is not coupled to the particleComment: 7 pages, 5 figures, submitted to Europhys. Let
Dynamic surface scaling behavior of isotropic Heisenberg ferromagnets
The effects of free surfaces on the dynamic critical behavior of isotropic
Heisenberg ferromagnets are studied via phenomenological scaling theory,
field-theoretic renormalization group tools, and high-precision computer
simulations. An appropriate semi-infinite extension of the stochastic model J
is constructed, the boundary terms of the associated dynamic field theory are
identified, its renormalization in d <= 6 dimensions is clarified, and the
boundary conditions it satisfies are given. Scaling laws are derived which
relate the critical indices of the dynamic and static infrared singularities of
surface quantities to familiar static bulk and surface exponents. Accurate
computer-simulation data are presented for the dynamic surface structure
factor; these are in conformity with the predicted scaling behavior and could
be checked by appropriate scattering experiments.Comment: 9 pages, 2 figure
Guided Neuronal Growth on Arrays of Biofunctionalized GaAs/InGaAs Semiconductor Microtubes
We demonstrate embedded growth of cortical mouse neurons in dense arrays of
semiconductor microtubes. The microtubes, fabricated from a strained
GaAs/InGaAs heterostructure, guide axon growth through them and enable
electrical and optical probing of propagating action potentials. The coaxial
nature of the microtubes -- similar to myelin -- is expected to enhance the
signal transduction along the axon. We present a technique of suppressing
arsenic toxicity and prove the success of this technique by overgrowing
neuronal mouse cells.Comment: 3 pages, 4 figure
On Critical Exponents and the Renormalization of the Coupling Constant in Growth Models with Surface Diffusion
It is shown by the method of renormalized field theory that in contrast to a
statement based on a mathematically ill-defined invariance transformation and
found in most of the recent publications on growth models with surface
diffusion, the coupling constant of these models renormalizes nontrivially.
This implies that the widely accepted supposedly exact scaling exponents are to
be corrected. A two-loop calculation shows that the corrections are small and
these exponents seem to be very good approximations.Comment: 4 pages, revtex, 2 postscript figures, to appear in Phys.Rev.Let
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