Degradable emulsion-templated scaffolds for tissue engineering from thiol– ene photopolymerisation

Emulsion templating has been used to prepare highly porous polyHIPE materials by thiol–ene photoinitiated network formation. Commercially available multifunctional thiols and acrylates were formulated into water-in-oil high internal phase emulsions (HIPEs) using an appropriate surfactant, and the HIPEs were photo-cured. The temperature of the HIPE aqueous phase was found to influence the morphology of the resulting materials. In agreement with previous work, a higher aqueous phase temperature (80 °C) gave rise to a larger mean void and interconnect diameter. The influence of temperature on morphology was found to be reduced at higher porosity, but still significant. The Young's modulus of the porous materials was shown to be related to the functionality of the acrylate comonomer used. A mixture of penta- and hexa-acrylate gave rise to a 100-fold increase in modulus, compared to an analogous tri-functional acrylate. The materials could be functionalised conveniently by addition of mono-acrylates or thiols to the organic phase of the precursor HIPE. Degradation was observed to occur at a rate depending on the degradation conditions. Under cell culture conditions at 37 °C, 19% mass loss occurred over 15 weeks. The scaffolds were found to be capable of supporting the growth of keratinocytic cells (HaCaTs) over 11 days in culture. Some penetrative in-growth of the cells into the scaffold was observed

The balance between Gα_i-Cdc42/Rac and Gα_12/13-RhoA pathways determines endothelial barrier regulation by sphingosine-1-phosphate

The bioactive sphingosine-1-phosphatephosphate (S1P) is present in plasma, bound to carrier proteins, and involved in many physiological processes, including angiogenesis, inflammatory responses, and vascular stabilization. S1P can bind to several G-protein-coupled receptors (GPCRs) activating a number of different signaling networks. At present, the dynamics and relative importance of signaling events activated immediately downstream of GPCR activation are unclear. To examine these, we used a set of fluorescence resonance energy transfer-based biosensors for different RhoGTPases (Rac1, RhoA/B/C, and Cdc42) as well as for heterotrimeric G-proteins in a series of live-cell imaging experiments in primary human endothelial cells. These experiments were accompanied by biochemical GTPase activity assays and transendothelial resistance measurements. We show that S1P promotes cell spreading and endothelial barrier function through S1PR1-Gαi-Rac1 and S1PR1-Gαi-Cdc42 pathways. In parallel, a S1PR2-Gα12/13-RhoA pathway is activated that can induce cell contraction and loss of barrier function, but only if Gαi-mediated signaling is suppressed. Our results suggest that Gαq activity is not involved in S1P-mediated regulation of barrier integrity. Moreover, we show that early activation of RhoA by S1P inactivates Rac1 but not Cdc42, and vice versa. Together, our data show that the rapid S1P-induced increase in endothelial integrity is mediated by a S1PR1-Gαi-Cdc42 pathwa

Striking Isotopologue-Dependent Photodissociation Dynamics of Water Molecules:The Signature of an Accidental Resonance

Investigations of the photofragmentation patterns of both light and heavy water at the state-to-state level are a prerequisite for any thorough understanding of chemical processing and isotope heterogeneity in the interstellar medium. Here we reveal dynamical features of the dissociation of water molecules following excitation to the (C) over tilde (010) state using a tunable vacuum ultraviolet source in combination with the high-resolution H(D)-atom Rydberg tagging time-of-flight technique. The action spectra for forming H(D) atoms and the OH(OD) product state distributions resulting from excitation to the (C) over tilde (010) states of H2O and D2O both show striking differences, which are attributable to the effects of an isotopologue-specific accidental resonance. Such accidental-resonance-induced state mixing may contribute to the D/H isotope heterogeneity in the solar system. The present study provides an excellent example of competitive state-to-state nonadiabatic decay pathways involving at least five electronic states

A self-consistent method to analyze the effects of the positive Q-value neutron transfers on fusion

AbstractConsidering the present limitation of the need for external parameters to describe the nucleus–nucleus potential and the couplings in the coupled-channels calculations, this work introduces an improved method without adjustable parameter to overcome the limitation and then sort out the positive Q-value neutron transfers (PQNT) effects based on the CCFULL calculations. The corresponding analysis for Ca+Ca, S,Ca+Sn, and S,Ca+Zr provides a reliable proof and a quantitative evaluation for the residual enhancement (RE) related to PQNT. In addition, the RE for S32,Ca40+Zr94 shows an unexpected larger enhancement than S32,Ca40+Zr96 despite the similar multi-neutron transfer Q-values. This method should rather strictly test the fusion models and be helpful for excavating the underlying physics

Exclusion Statistics of Quasiparticles in Condensed States of Composite Fermion Excitations

The exclusion statistics of quasiparticles is found at any level of the hierarchy of condensed states of composite fermion excitations (for which experimental indications have recently been found). The hierarchy of condensed states of excitations in boson Jain states is introduced and the statistics of quasiparticles is found. The quantum Hall states of charged $\alpha$-anyons ($\alpha$ -- the exclusion statistics parameter) can be described as incompressible states of $(\alpha+2p)$-anyons ($2p$ -- an even number).Comment: 4 page

Quasi-Periodic Releases of Streamer Blobs and Velocity Variability of the Slow Solar Wind near the Sun

We search for persistent and quasi-periodic release events of streamer blobs during 2007 with the Large Angle Spectrometric Coronagraph on the \textit{Solar and Heliospheric Observatory} and assess the velocity of the slow solar wind along the plasma sheet above the corresponding streamer by measuring the dynamic parameters of blobs. We find 10 quasi-periodic release events of streamer blobs lasting for three to four days. In each day of these events, we observe three-five blobs. The results are in line with previous studies using data observed near the last solar minimum. Using the measured blob velocity as a proxy for that of the mean flow, we suggest that the velocity of the background slow solar wind near the Sun can vary significantly within a few hours. This provides an observational manifestation of the large velocity variability of the slow solar wind near the Sun.Comment: 14 pages, 5 figures, accepted by Soalr Physic

Critical flux pinning and enhanced upper-critical-field in magnesium diboride films

We have conducted pulsed transport measurements on c-axis oriented magnesium diboride films over the entire relevant ranges of magnetic field 0 \alt H \alt H_{c2} (where \hcu is the upper critical field) and current density 0 \alt j \alt j_{d} (where $j_{d}$ is the depairing current density). The intrinsic disorder of the films combined with the large coherence length and three-dimensionality, compared to cuprate superconductors, results in a six-fold enhancement of $H_{c2}$ and raises the depinning current density $j_{c}$ to within an order of magnitude of $j_{d}$. The current-voltage response is highly non-linear at all fields, resulting from a combination of depinning and pair-breaking, and has no trace of an Ohmic free-flux-flow regime. Keywords: pair, breaking, depairing, superconductor, superconductivity, flux, fluxon, vortex, mgb

Dissection of genetic variation and evidence for pleiotropy in male pattern baldness.

Male pattern baldness (MPB) is a sex-limited, age-related, complex trait. We study MPB genetics in 205,327 European males from the UK Biobank. Here we show that MPB is strongly heritable and polygenic, with pedigree-heritability of 0.62 (SE = 0.03) estimated from close relatives, and SNP-heritability of 0.39 (SE = 0.01) from conventionally-unrelated males. We detect 624 near-independent genome-wide loci, contributing SNP-heritability of 0.25 (SE = 0.01), of which 26 X-chromosome loci explain 11.6%. Autosomal genetic variance is enriched for common variants and regions of lower linkage disequilibrium. We identify plausible genetic correlations between MPB and multiple sex-limited markers of earlier puberty, increased bone mineral density (r <sub>g</sub>  = 0.15) and pancreatic β-cell function (r <sub>g</sub>  = 0.12). Correlations with reproductive traits imply an effect on fitness, consistent with an estimated linear selection gradient of -0.018 per MPB standard deviation. Overall, we provide genetic insights into MPB: a phenotype of interest in its own right, with value as a model sex-limited, complex trait