Surface modification of biodegradable vascular grafts is an important strategy to improve the in situ endothelialization of tissue engineered vascular grafts (TEVGs) and prevent major complications ...associated with current synthetic grafts. Important strategies for improving endothelialization include increasing endothelial cell mobilization and increased endothelial cell capture through biofunctionalization of TEVGs. The objective of this study was to assess two biofunctionalization strategies for improving endothelialization of biodegradable polyester vascular grafts. These techniques consisted of cross-linking heparin to graft surfaces to immobilize vascular endothelial growth factor (VEGF) or antibodies against CD34 (anti-CD34Ab). To this end, heparin, VEGF, and anti-CD34Ab attachment and quantification assays confirmed the efficacy of the modification strategy. Cell attachment and proliferation on these groups were compared to unmodified grafts in vitro and in vivo. To assess in vivo graft functionality, the grafts were implanted as inferior vena cava interpositional conduits in mice. Modified vascular grafts displayed increased endothelial cell attachment and activity in vivo, according to microscopy techniques, histological results, and eNOS expression. Inner lumen diameter of the modified grafts was also better maintained than controls. Overall, while both functionalized grafts outperformed the unmodified control, grafts modified with anti-CD34Ab appeared to yield the most improved results compared to VEGF-loaded grafts.
Particles with millicharge q and sub-eV mass can be produced in photon–photon collisions, distorting the energy spectrum of the Cosmic Microwave Background. We derive the conservative bound q≲10−7e ...(as well as model-dependent bounds two orders of magnitude stronger), incompatible with proposed interpretations of the PVLAS anomaly based on millicharged production or on millicharged-mediated axion-like couplings.
We report new constraints on the reheating temperature of the universe by analyzing the recent cosmic microwave background (CMB) data from the WMAP five year survey. From WMAP-5 data alone we found ...an upper limit at 95% c.l. of
T
rh
>
2
MeV, while including external priors from the SDSS red luminous galaxy survey and age constraints improves the limit to
T
rh
>
3.2
MeV (again at 95% c.l.). Future analysis from combined CMB and weak lensing surveys as Planck and DUNE will improve the the constraints by a factor ∼2. We test the stability of the current upper limits on neutrino masses from cosmology under the hypothesis of non-standard thermal neutrino background.
Congenital heart defect interventions may benefit from the fabrication of patient-specific vascular grafts because of the wide array of anatomies present in children with cardiovascular defects. 3D ...printing is used to establish a platform for the production of custom vascular grafts, which are biodegradable, mechanically compatible with vascular tissues, and support neotissue formation and growth.
► Neutrinos leave a distinct imprint on the large scale structure of the Universe. ► Large surveys are sensitive to the sum of the neutrino masses. ► We collect and explain current and future ...constraints from different probes of the structure of the Universe.
Cosmological and astrophysical measurements provide powerful constraints on neutrino masses complementary to those from accelerators and reactors. Here we provide a guide to these different probes, for each explaining its physical basis, underlying assumptions, current and future reach.
We investigate the possibility of constraining dark energy with the Integrated Sachs Wolfe effect recently detected by cross-correlating the WMAP maps with several Large Scale Structure surveys. In ...agreement with previous works, we found that, under the assumption of a flat universe, the ISW signal is a promising tool for constraining dark energy. Current available data put weak limits on a constant dark energy equation of state w. We also find no constraints on the dark energy sound speed c_e^2. For quintessence-like dark energy (c_e^2=1) we find w<-0.53, while tighter bounds are possible only if the dark energy is ``clustered'' (c_e^2=0), in such a case -1.94<w<-0.63 at 2-sigma. Better measurements of the CMB-LSS correlation will be possible with the next generation of deep redshift surveys. This will provide independent constraints on the dark energy which are alternative to those usually inferred from CMB and SN-Ia data.
In this review we describe the formation and evolution of topological defects which may form during symmetry breaking phase transitions in the early Universe. After an introduction to cosmological ...perturbation theory, we discuss the scale invariant spectrum of fluctuations induced by defects in a homogeneous and isotropic universe. We describe the numerical calculation of anisotropies and polarization of the cosmic microwave background and show that the pattern of acoustic peaks, characteristic of inflationary models and observed in the data, is absent for global
O(
N) defects and for cosmic strings. We reveal the origin of this result and we study whether more general ‘scaling causal seeds’ may be brought in agreement with present data. We also investigate mixed models where cosmological perturbations come from the amplification quantum fluctuations generated during an inflationary phase and from defects created at the end of inflation.
PDF
