Short SULF1/SULF2 splice variants predominate in mammary tumours with a potential to facilitate receptor tyrosine kinase-mediated cell signalling

The relative roles of SULF1 and SULF2 enzymes in tumour growth are controversial, but short SULF1/SULF2 splice variants predominate in human mammary tumours despite their non-detectable levels in normal mammary tissue. Compared with the normal, the level of receptor tyrosine kinase (RTK) activity was markedly increased in triple-positive mammary tumours during later stages of tumour progression showing increased p-EGFR, p-FGFR1 and p-cMet activity in triple-positive but not in triple-negative tumours. The abundance of catalytically inactive short SULF1/SULF2 variants permits high levels of HS sulphation and thus growth driving RTK cell signalling in primary mammary tumours. Also observed in this study, however, was increased N-sulphation detected by antibody 10E4 indicating that not only 6-O sulphation but also N-sulphation may contribute to increased RTK cell signalling in mammary tumours. The levels of such increases in not only SULF1/SULF2 but also in pEGFR, pFGFR1, p-cMet and Smad1/5/8 signalling were further enhanced following lymph node metastasis. The over-expression of Sulf1 and Sulf2 variants in mammary tumour-derived MDA-MB231 and MCF7 cell lines by transfection further confirms Sulf1-/Sulf2-mediated differential modulation of growth. The short variants of both Sulf1 and Sulf2 promoted FGF2-induced MDA-MB231 and MCF7 in vitro growth while full-length Sulf1 inhibited growth supporting in vivo mammary tumour cell signalling patterns of growth. Since a number of mammary tumours become drug resistant to hormonal therapy, Sulf1/Sulf2 inhibition could be an alternative therapeutic approach to target such tumours by down-regulating RTK-mediated cell signalling

A simple sandpile model of active-absorbing state transitions

We study a simple sandpile model of active-absorbing state transitions in which a particle can hop out of a site only if the number of particles at that site is above a certain threshold. We show that the active phase has product measure whereas nontrivial correlations are found numerically in the absorbing phase. It is argued that the system relaxes to the latter phase slower than exponentially. The critical behavior of this model is found to be different from that of the other known universality classes.Comment: Revised version. To appear in Phys. Rev.

TCAD Simulations and Small Signal Modeling of DMG AlGaN/GaN HFET

This article presents extraction of small signal model parameters and TCAD simulation of novel asymmetric field plated dual material gate AlGaN/GaN HFET first time. Small signal model is essential for design of LNA and microwave electronic circuit by using the proposed superior performance HFET structure. Superior performances of device are due to its dual material gate structure and field plate that can provide better electric field uniformity, suppression of short channel effects and improvement in carrier transport efficiency. In this article we used direct parameter extraction methodology in which S-parameters of device were measured using pinchoff cold FET biasing. The measured S-parameters are then transformed into Y-parameters to extract capacitive elements and then in to Z-parameters to extract series parasitic elements. Intrinsic parameters are extracted from Y-parameters after de-embedding all parasitic elements of devce. Microwave figure of merits and dc performance are also studied for proposed HFET. The important figure of merits of device reported in the paper include transconductance, drain conductance, current gain, transducer power gain, available power gain, maximum stable gain, maximum frequency of oscillation, cut-off frequency, stability factor and time delay. Reported results are validated with experimental and simulation results for consistency and accuracy

Correlation of endothelial cell proliferation with vascular endothelial growth factor in endometrium of women with menorrhagia

Background: Approximately 30% of women of reproductive age experience excessive blood loss during menstruation. In 50% of cases, menorrhagia has no underlying pathology. However, until recently, the only permanent cure for menorrhagia was hysterectomy. In this study we aim to determine the correlation of vascular endothelial growth factor (VEGF) expression with markers of endometrial endothelial cell proliferation like proliferating cell nuclear antigen (PCNA) and Cluster Determination (CD34).Methods: A total of 100 patients with history of menorrhagia were selected for study. Double Immunohistochemistry was performed on these endometrial biopsy sections. Proliferating endothelial cells were identified by an immunohistochemical double staining technique with PCNA and CD34. VEGF expression was also seen in endometrial biopsy.Results: In general, expression of both VEGF and PCNA was more in functional layer than basal layer in both menorrhagic patients as well as non menorrhagic patients.  When glandular cytoplasmic VEGF expression was compared with PCNA the association was statistically significant whereas completely opposite findings was seen with glandular luminal surface VEGF positivity but the association was statistically significant. In secretory phase (p-value<0.001) there was highly statistically significant association in PCNA grading with glandular luminal surface VEGF positivity whereas when we correlated PCNA with  cytoplasmic  glandular VEGF in secretory phase it was statistically significant (p-value<0.001).Conclusions: The endothelial proliferation was significantly higher in menorrhagia patients during late secretory phase of cycle than controls. We were able to demonstrate increased endothelial proliferation in patients in the premenstrual part of cycle

Field equations from a surface term

As is well known, in order for the Einstein--Hilbert action to have a well defined variation, and therefore to be used for deriving field equation through the stationary action principle, it has to be amended by the addition of a suitable boundary term. It has recently been claimed that, if one constructs an action by adding this term to the matter action, the Einstein field equations can be derived by requiring this action to be invariant under active transformations which are normal to a null boundary. In this paper we re-examine this approach both for the case of pure gravity and in the presence of matter. We show that in the first case this procedure holds for more general actions than the Einstein-Hilbert one and trace the basis of this remarkable attribute. However, it is also pointed out the when matter is rigorously considered the approach breaks down. The reasons for that are thoroughly discussed.Comment: Typos corrected, minor changes to match published versio

Galilean Gauge Theories from Null Reductions

The procedure of null reduction provides a concrete way of constructing field theories with Galilean invariance. We use this to examine Galilean gauge theories, viz. Galilean electrodynamics and Yang-Mills theories in spacetime dimensions 3 and 4. Different non-relativistic conformal symmetries arise in these contexts: Schr{\"o}dinger symmetry in $d=3$ and Galilean conformal symmetry in $d=4$. A canonical analysis further reveals that the symmetries enhance to their infinite dimensional versions in phase space and pick up central extensions. In addition, for the Abelian theory, we discuss non-relativistic electro-magnetic duality in $d=3$ and its difference with the $d=4$ version. We also mention some quantum aspects for both Abelian and non-Abelian theories

Porcine brachial artery tortuosity for in vivo evaluation of neuroendovascular devices

We report a novel model of arterial tortuosity in the porcine brachial artery for testing of endovascular devices in the flexed forelimb position. This provides an ideal vascular territory for an in vivo assessment of guidewires, microcatheters, and endovascular implants because it closely mimics the challenging curvature at the carotid siphon

Interior Weyl-type Solutions of the Einstein-Maxwell Field Equations

Static solutions of the electro-gravitational field equations exhibiting a functional relationship between the electric and gravitational potentials are studied. General results for these metrics are presented which extend previous work of Majumdar. In particular, it is shown that for any solution of the field equations exhibiting such a Weyl-type relationship, there exists a relationship between the matter density, the electric field density and the charge density. It is also found that the Majumdar condition can hold for a bounded perfect fluid only if the matter pressure vanishes (that is, charged dust). By restricting to spherically symmetric distributions of charged matter, a number of exact solutions are presented in closed form which generalise the Schwarzschild interior solution. Some of these solutions exhibit functional relations between the electric and gravitational potentials different to the quadratic one of Weyl. All the non-dust solutions are well-behaved and, by matching them to the Reissner-Nordstr\"{o}m solution, all of the constants of integration are identified in terms of the total mass, total charge and radius of the source. This is done in detail for a number of specific examples. These are also shown to satisfy the weak and strong energy conditions and many other regularity and energy conditions that may be required of any physically reasonable matter distribution.Comment: 21 pages, RevTex, to appear in General Relativity and Gravitatio

Perfectly Translating Lattices on a Cylinder

We perform molecular dynamics simulations on an interacting electron gas confined to a cylindrical surface and subject to a radial magnetic field and the field of the positive background. In order to study the system at lowest energy states that still carry a current, initial configurations are obtained by a special quenching procedure. We observe the formation of a steady state in which the entire electron-lattice cycles with a common uniform velocity. Certain runs show an intermediate instability leading to lattice rearrangements. A Hall resistance can be defined and depends linearly on the magnetic field with an anomalous coefficient reflecting the manybody contributions peculiar to two dimensions.Comment: 13 pages, 5 figure

The Tolman VII solution, trapped null orbits and w - modes

The Tolman VII solution is an exact static spherically symmetric perfect fluid solution of Einstein's equations that exhibits a surprisingly good approximation to a neutron star. We show that this solution exhibits trapped null orbits in a causal region even for a tenuity (total radius to mass ratio) $> 3$. In this region the dynamical part of the potential for axial w - modes dominates over the centrifugal part.Comment: 5 pages revtex. 10 figures png. Further information at http://grtensor.phy.queensu.ca/tolmanvii