278 research outputs found
Chemokine receptor trio: CXCR3, CXCR4 and CXCR7 crosstalk via CXCL11 and CXCL12.
Although chemokines are well established to function in immunity and endothelial cell activation and proliferation, a rapidly growing literature suggests that CXC Chemokine receptors CXCR3, CXCR4 and CXCR7 are critical in the development and progression of solid tumors. The effect of these chemokine receptors in tumorigenesis is mediated via interactions with shared ligands I-TAC (CXCL11) and SDF-1 (CXCL12). Over the last decade, CXCR4 has been extensively reported to be overexpressed in most human solid tumors and has earned considerable attention toward elucidating its role in cancer metastasis. To enrich the existing armamentarium of anti-cancerous agents, many inhibitors of CXCL12-CXCR4 axis have emerged as additional or alternative agents for neo-adjuvant treatments and even many of them are in preclinical and clinical stages of their development. However, the discovery of CXCR7 as another receptor for CXCL12 with rather high binding affinity and recent reports about its involvement in cancer progression, has questioned the potential of "selective blockade" of CXCR4 as cancer chemotherapeutics. Interestingly, CXCR7 can also bind another chemokine CXCL11, which is an established ligand for CXCR3. Recent reports have documented that CXCR3 and their ligands are overexpressed in different solid tumors and regulate tumor growth and metastasis. Therefore, it is important to consider the interactions and crosstalk between these three chemokine receptors and their ligand mediated signaling cascades for the development of effective anti-cancer therapies. Emerging evidence also indicates that these receptors are differentially expressed in tumor endothelial cells as well as in cancer stem cells, suggesting their direct role in regulating tumor angiogenesis and metastasis. In this review, we will focus on the signals mediated by this receptor trio via their shared ligands and their role in tumor growth and progression
A Cosmological Model of Thermodynamic Open Universe
In this paper we have given a generalisation of the earlier work by Prigogine
et al. who have constructed a phenomenological model of entropy production via
particle creation in the very early universe generated out of the vacuum rather
than from a singularity, by including radiation also as the energy source and
tried to develop an alternative cosmological model in which particle creation
prevents the big bang. We developed Radiation dominated model of the universe
which shows a general tendency that (i) it originates from instability of
vacuum rather than from a singularity. (ii) Up to a characteristic time
cosmological quantities like density, pressure, Hubble constant and expansion
parameter vary rapidly with time. (iii) After the characteristic time these
quantities settles down and the models are turned into de-sitter type model
with uniform matter, radiation, creation densities and Hubble's constant H. The
de-sitter regime survives during a decay time then connects continuously to a
usual adiabatic matter radiation RW universe.The interesting thing in the paper
is that we have related the phenomenological radiation dominated model to
macroscopic model of quantum particle creation in the early universe giving
rise to the present observed value of cosmic background radiation . It is also
found that the dust filled model tallies exactly with that of the Prigogine's
one, which justifies that our model is generalized Prigogine's model. Although
the model originates from instability of vacuum rather than from a singularity,
still there is a couple of unavoidable singularities in the model.Comment: 10,Accepted for publication in International journal of theoretical
physics,doi:10.1007/s10773-012-1142-
A Honeycomb Proportional Counter for Photon Multiplicity Measurement in the ALICE Experiment
A honeycomb detector consisting of a matrix of 96 closely packed hexagonal
cells, each working as a proportional counter with a wire readout, was
fabricated and tested at the CERN PS. The cell depth and the radial dimensions
of the cell were small, in the range of 5-10 mm. The appropriate cell design
was arrived at using GARFIELD simulations. Two geometries are described
illustrating the effect of field shaping. The charged particle detection
efficiency and the preshower characteristics have been studied using pion and
electron beams. Average charged particle detection efficiency was found to be
98%, which is almost uniform within the cell volume and also within the array.
The preshower data show that the transverse size of the shower is in close
agreement with the results of simulations for a range of energies and converter
thicknesses.Comment: To be published in NIM
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