H-ATLAS/GAMA: magnification bias tomography. Astrophysical constraints above ~1 arcmin

An unambiguous manifestation of the magnification bias is the cross-correlation between two source samples with non-overlapping redshift distributions. In this work we measure and study the cross-correlation signal between a foreground sample of GAMA galaxies with spectroscopic redshifts in the range 0.2<z<0.8, and a background sample of H-ATLAS galaxies with photometric redshifts gsim1.2. It constitutes a substantial improvement over the cross-correlation measurements made by Gonzalez-Nuevo et al. (2014) with updated catalogues and wider area (with S/Ngsim 5 below 10 arcmin and reaching S/N~ 20 below 30 arcsec). The better statistics allow us to split the sample in different redshift bins and to perform a tomographic analysis (with S/Ngsim 3 below 10 arcmin and reaching S/N~ 15 below 30 arcsec). Moreover, we implement a halo model to extract astrophysical information about the background galaxies and the deflectors that are producing the lensing link between the foreground (lenses) and background (sources) samples. In the case of the sources, we find typical mass values in agreement with previous studies: a minimum halo mass to host a central galaxy, Mmin~ 1012.26 M⊙, and a pivot halo mass to have at least one sub-halo satellite, M1~ 1012.84 M⊙. However, the lenses are massive galaxies or even galaxy groups/clusters, with minimum mass of Mminlens~ 1013.06 M⊙. Above a mass of M1lens~ 1014.57 M⊙ they contain at least one additional satellite galaxy which contributes to the lensing effect. The tomographic analysis shows that, while M1lens is almost redshift independent, there is a clear evolution of increase Mminlens with redshift in agreement with theoretical estimations. Finally, the halo modeling allows us to identify a strong lensing contribution to the cross-correlation for angular scales below 30 arcsec. This interpretation is supported by the results of basic but effective simulations

Integrating gas sorption with mercury porosimetry

Previous work has shown that it is possible to use integrated nitrogen sorption and mercury porosimetry experiments to determine the distribution of average pore length with pore diameter for mesoporous solids. In this work, the previous data analysis method has been generalised such that it is also suitable for application to samples with higher levels of mercury entrapment than before. This generalisation of the theory has facilitated the ability to use a series of progressively larger mercury scanning loops, in integrated gas sorption and porosimetry experiments, to potentially determine the full pore length distribution for pores of a given diameter, and the distribution of pore co-ordination number. The new analysis has been applied to a silica catalyst support

Engineering silica particles as oral drug delivery vehicles

Porous silica particles are emerging as complementary systems to polyester microspheres for the encapsulation and controlled delivery of small-organic drugs. Their recent application in pharmaceutics is strengthened by well-established characterization and synthetic routes from the chemical engineering sciences. Silica is an interesting scaffold material for the encapsulation of organic molecules. It can be formed into hierarchical structures over a wide range of length scales and interconnectivities. Encapsulation can therefore be tailored not only to the drug but the desired release properties. In addition to surfactant-templating of hierarchical silica structures, polypeptides from marine organisms may offer biological routes to novel silica materials. Silica sol-gels have also been evaluated as delivery vehicles, particularly with regard to generating hybrid systems with mesoporous silica or composite xerogels. This review will first focus on the detailed characterisation of pore size and structure of mesoporous silica with regards water penetration and drug diffusion. We then describe the pharmaceutical applications of silica materials with regard to improving oral bioavailability, multiparticulate systems for gastroretention or sustained release, composite xerogels and in vivo biocompatibility

Post-CO2 injection alteration of the pore network and intrinsic permeability tensor for a Permo-Triassic sandstone

The aim of this study was to determine the process–structure–property relationships between the pre- and post- CO 2 injection pore network geometry and the intrinsic permeability tensor for samples of core from low-perme- ability Lower Triassic Sherwood Sandstone, UK. Samples were characterised using SEM-EDS, XRD, MIP, XRCT and a triaxial permeability cell both before and after a three-month continuous-flow experiment using acidic CO 2 -rich saline fluid. The change in flow properties was compared to those predicted by pore-scale numerical modelling using an implicit finite volume solution to the Navier–Stokes equations. Mass loss and increased secondary porosity appeared to occur primarily due to dissolution of intergranular cements and K-feldspar grains, with some associ- ated loss of clay, carbonate and mudstone clasts. This resulted in a bulk porosity increase from 18 to 25% and caused a reduction in mean diameter of mineral grains with an increase in apparent pore wall roughness, where the fractal dimension, D f , increased from 1.68 to 1.84. All significant dissolution mass loss occurred in pores above c. 100 lm mean diameter. Relative dilation of post-treatment pore area appeared to increase in relation to initial pore area, suggesting that the rate of dissolution mass loss had a positive relationship with fluid flow velocity; that is, critical flow pathways are preferentially widened. Variation in packing density within sedimentary planes (occur- ring at cm-scale along the - z plane) caused the intrinsic permeability tensor to vary by more than a factor of ten. The bulk permeability tensor is anisotropic having almost equal value in - z and - y planes but with a 68% higher value in the - x plane (parallel to sedimentary bedding planes) for the pretreated sample, reducing to only 30% higher for the post-treated sample. The intrinsic permeability of the post-treatment sample increased by one order of magnitude and showed very close agreement between the modelled and experimental result