In vitro evaluation of Pediococcus acidilactici NCDC 252 for its probiotic attributes

In vitro probiotic attributes of Pediococcus acidilactici, viz. tolerance to acidity and bile salt, phenol resistance, lactic acid production, antioxidant activity, cell surface hydrophobicity, lysozyme resistance and the presence of β‐galactosidase, proteolytic, lipase and peptidoglycan hydrolase activities, were studied. The strain was found to be rich in different proteolytic activities, β‐galactosidase and antioxidant activities, and produced lactic acid. The studies conducted support that P. acidilactici national collection of dairy cultures (NCDC) 252 is a potential probiotic for humans with all the essential basic probiotic properties. This testing is useful to gain insight into this strain and its mechanism of action. All these attributes add to its therapeutic importance and industrial significance.     

Variational Bayes Based Multiuser Detection for On–Off Random Access Channels

This paper considers on–off random access channels where the users transmit either a one or a zero to a base station or fusion center, and it is assumed that only a small fraction of users are active during any channel use. Under these assumptions, the problem of identifying the active users reduces to that of recovering a sparse binary vector from noisy random linear measurements. A hierarchical Bayesian approach is proposed in this paper to recover the set of active users. A fast approximate Bayesian inference based on Variational Bayes (VB) is then developed. Extensive simulation results are then provided to compare the performance of the proposed VB based Bayesian MUD approach to sparse estimation techniques such as OMP and LASSO. It is observed that the proposed approach is robust to variations in noise as well as sparsity levels. Further, for a given BER performance, the proposed approach requires substantially smaller dimensional codes as compared to OMP and LASSO, thus improving the spectral efficiency.     

Representing scientific data sets in KML: Methods and challenges

Virtual Globes such as Google Earth and NASA World Wind permit users to explore rich imagery and the topography of the Earth. While other online services such as map servers provide ways to view, query, and download geographic information, the public has become captivated with the ability to view the Earth’s features virtually. The National Snow and Ice Data Center began to display scientific data on Virtual Globes in 2006. The work continues to evolve with the production of high-quality Keyhole Markup Language (KML) representations of scientific data and an assortment of technical experiments. KML files are interoperable with many Virtual Globe or mapping software packages. This paper discusses the science benefits of Virtual Globes, summarizes KML creation methods, and introduces a guide for selecting tools and methods for authoring KML for use with scientific data sets.     

Ethylene-propylene diene monomer-based polymer composite for attenuation of high energy radiations

Radiation shielding composites of ethylene-propylene diene monomer (EPDM), reinforced with tungsten (W) and barium sulphate (BaSO₄) in different filler weight (wt%) were synthesized. The effects of W and BaSO₄ on gamma and neutron attenuation properties of the composites were studied by experimental methods using ¹³⁷Cs, ⁶⁰Co and ²⁵²Cf radioactive sources. EPDM composites with W and BaSO₄ fillers were also investigated for filler dispersion using scanning electron microscopy and X-ray radiograph. The experimental results revealed that the incorporation of W and BaSO₄ significantly improved the radiation attenuation properties of the EPDM composites. It was observed that the attenuation properties of the composite material increases with higher concentration of the filler. The half-value layer (HVL), tenth value layer thickness and relaxation length of the composites were found to decrease with increasing concentration of the filler. The results also showed that the attenuation behaviour of 50 wt% BaSO₄ filled polymer composite is comparable to that of the composite with 25 wt% W. The developed composite with 75 wt% W filler exhibited the maximum radiation attenuation with lowest HVL thicknesses.     

Low pressure dependent elasticity of porous ceramics

The primary goal of this study was to characterize the influence of the pore-saturated gas media and their physical properties on the elasticity of porous ceramic materials. Resonant ultrasound spectroscopic measurements were performed on test specimens of alumina with ~40% porosity, zirconia with ~48% porosity, and sintered fully dense zirconia to determine the hydrostatic pressure-dependent macroscopic elasticity. Here, we report the variation of elasticity of porous and full dense samples over approximately five orders of magnitude (800-0.02 psi) in absolute pressure. The time evolution of mechanical equilibrium of the porous materials at low pressure and high-temperature conditions will also be discussed.