5,699 research outputs found
Experimental investigations in epitaxial growth of crystalline layers final report
Epitaxial growth of crystalline layer
Hypoxic Culture Conditions as a Solution for Mesenchymal Stem Cell Based Regenerative Therapy
Cell-based regenerative therapies, based on in vitro propagation of stem cells, offer tremendous hope to many individuals suffering from degenerative diseases that were previously deemed untreatable. Due to the self-renewal capacity, multilineage potential, and immunosuppressive property, mesenchymal stem cells (MSCs) are considered as an attractive source of stem cells for regenerative therapies. However, poor growth kinetics, early senescence, and genetic instability during in vitro expansion and poor engraftment after transplantation are considered to be among the major disadvantages of MSC-based regenerative therapies. A number of complex inter-and intracellular interactive signaling systems control growth, multiplication, and differentiation of MSCs in their niche. Common laboratory conditions for stem cell culture involve ambient O-2 concentration (20%) in contrast to their niche where they usually reside in 2-9% O-2. Notably, O-2 plays an important role in maintaining stem cell fate in terms of proliferation and differentiation, by regulating hypoxia-inducible factor-1 (HIF-1) mediated expression of different genes. This paper aims to describe and compare the role of normoxia (20% O-2) and hypoxia (2-9% O-2) on the biology of MSCs. Finally it is concluded that a hypoxic environment can greatly improve growth kinetics, genetic stability, and expression of chemokine receptors during in vitro expansion and eventually can increase efficiency of MSC-based regenerative therapies.Article Link:
http://www.hindawi.com/journals/tswj/2013/632972
Pairing of a trapped resonantly-interacting fermion mixture with unequal spin populations
We consider the phase separation of a trapped atomic mixture of fermions with
unequal spin populations near a Feshbach resonance. In particular, we determine
the density profile of the two spin states and compare with the recent
experiments of Partridge et al. (cond-mat/0511752). Overall we find quite good
agreement. We identify the remaining discrepancies and pose them as open
problems.Comment: 4 figures, 4+ pages, revtex
Far-Field Plasmonic Resonance Enhanced Nano-Particle Image Velocimetry within a Micro Channel
In this paper, a novel far-field plasmonic resonance enhanced
nanoparticle-seeded Particle Image Velocimetry (nPIV) has been demonstrated to
measure the velocity profile in a micro channel. Chemically synthesized silver
nanoparticles have been used to seed the flow in the micro channel. By using
Discrete Dipole Approximation (DDA), plasmonic resonance enhanced light
scattering has been calculated for spherical silver nanoparticles with
diameters ranging from 15nm to 200nm. Optimum scattering wavelength is
specified for the nanoparticles in two media: water and air. The
diffraction-limited plasmonic resonance enhanced images of silver nanoparticles
at different diameters have been recorded and analyzed. By using standard PIV
techniques, the velocity profile within the micro channel has been determined
from the images.Comment: submitted to Review of Scientific Instrument
Deformation of a Trapped Fermi Gas with Unequal Spin Populations
The real-space densities of a polarized strongly-interacting two-component
Fermi gas of Li atoms reveal two low temperature regimes, both with a
fully-paired core. At the lowest temperatures, the unpolarized core deforms
with increasing polarization. Sharp boundaries between the core and the excess
unpaired atoms are consistent with a phase separation driven by a first-order
phase transition. In contrast, at higher temperatures the core does not deform
but remains unpolarized up to a critical polarization. The boundaries are not
sharp in this case, indicating a partially-polarized shell between the core and
the unpaired atoms. The temperature dependence is consistent with a tricritical
point in the phase diagram.Comment: Accepted for publication in Physical Review Letter
Angiogenic Host Defense Peptide Ag-30/5C and Bradykinin B 2 receptor Antagonist Icatibant are G Protein Biased Agonists for MRGPRX2 in Mast Cells
AG-30/5C is an angiogenic host defense peptide that activates human mast cells (MC) via an unknown mechanism. Using short hairpin RNA–silenced human MC line LAD2 and stably transfected RBL-2H3 cells, we demonstrate that AG-30/5C induces MC degranulation via Mas-related G protein–coupled receptor X2 (MRGPRX2). Most G protein–coupled receptors signal via parallel and independent pathways mediated by G proteins and b-arrestins. AG-30/5C and compound 48/80 induced similar maximal MC degranulation via MRGPRX2, which was abolished by pertussis toxin. However, compound 48/80 induced a robust b-arrestin activation as determined by transcriptional activation following arrestin translocation (Tango), but AG-30/5C did not. Overnight culture of MC with compound 48/80 resulted in reduced cell surface MRGPRX2 expression, and this was associated with a significant decrease in subsequent MC degranulation in response to compound 48/80 or AG-30/5C. However, AG-30/5C pretreatment had no effect on cell surface MRGPRX2 expression or degranulation in response to compound 48/80 or AG-30/5C. Icatibant, a bradykinin B 2 receptor antagonist, promotes MC degranulation via MRGPRX2 and causes pseudoallergic drug reaction. Icatibant caused MC degranulation via a pertussis toxin–sensitive G protein but did not activate b-arrestin. A screen of the National Institutes of Health Clinical Collection library led to the identification of resveratrol as an inhibitor of MRGPRX2. Resveratrol inhibited compound 48/80–induced Tango and MC degranulation in response to compound 48/80, AG-30/5C, and Icatibant. This study demonstrates the novel finding that AG-30/5C and Icatibant serve as G protein–biased agonists for MRGPRX2, but compound 48/80 signals via both G protein and b-arrestin with distinct differences in receptor regulation. Copyright © 2019 by The American Association of Immunologists, Inc. All rights reserve
A Systematic Map of the UK Literature on Navigation Roles in Primary Care: Social Prescribing Link Workers in Context
Non-commutativity and Open Strings Dynamics in Melvin Universes
We compute the Moyal phase factor for open strings ending on D3-branes
wrapping a NSNS Melvin universe in a decoupling limit explicitly using world
sheet formalism in cylindrical coordinates.Comment: 12 pages, 1 figure, references adde
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