Use of enzymes and hydraulic press for the extraction of palm oil with increased oxidative stability

Palm oil is known as one of the important vegetable oils enriched with health beneficial constituents. However, improper extraction methods and storage conditions may lead to rancidity in vegetable oils and loss its oxidative stability. An aqueous enzymatic process was reported in yielding vegetable oil with increased antioxidant capacities. Meanwhile, previous studies extracted vegetable oil with lower oxidation products using hydraulic press. To date, no study explored the production of palm oil with increased oxidative stability against quality deterioration. Hence, this study is set out to exploit the use of enzymes and hydraulic press for their influence on the antioxidant capacities and oxidative stability of palm oil. The oil palm fruits were pre-treated with cellulase (S), pectinase (P) and tannase (T) at 0.5% enzyme solution (w/v), respectively, at a ratio of enzyme solution to pulp of 1:1 for 30 minutes of incubation time at 50ºC. All fruit samples were subjected to oil expression using the hydraulic press. Antioxidant capacities of oil sample SPT were found significantly higher, and these results were supported by its high content of total phenolic content and carotene content. In the oxidative stability assessment, the peroxide value, p-anisidine value and total oxidation value increased over the one-month storage period for all oil samples, with oil sample SPT significantly lower than other samples. This study revealed the potential of enzymatic pre-treatment with SPT on oil palm fruits and hydraulic press to obtain palm oils with increased oxidative stability

Poly[di-μ2-azido-μ3-pyrazine-2-carboxyl­ato-cadmium(II)]

The title compound, [Cd(C5H3N2O2)(N3)]n, has been pre­pared by the reaction of pyrazine-2-carboxylic acid, cadmium(II) nitrate and sodium azide. In the structure, the CdII atom is six-coordinated by two azide anions and three pyrazine-2-carboxyl­ate ligands. Each pyrazine-2-carboxyl­ate ligand bridges three CdII atoms, whereas the azide ligand bridges two CdII atoms, resulting in the formation of a two-dimensional metal–organic polymer developing parallel to the (100) plane

Stochastic Electron Acceleration in Shell-Type Supernova Remnants II

We discuss the generic characteristics of stochastic particle acceleration by a fully developed turbulence spectrum and show that resonant interactions of particles with high speed waves dominate the acceleration process. To produce the relativistic electrons inferred from the broadband spectrum of a few well-observed shell-type supernova remnants in the leptonic scenario for the TeV emission, fast mode waves must be excited effectively in the downstream and dominate the turbulence in the subsonic phase. Strong collisionless non-relativistic astrophysical shocks are studied with the assumption of a constant Aflven speed. The energy density of non-thermal electrons is found to be comparable to that of the magnetic field. With reasonable parameters, the model explains observations of shell-type supernova remnants. More detailed studies are warranted to better understand the nature of supernova shocks.Comment: 5 pages, 7 figures, submitted to Proceedings of the Conference on "2008 Heidelberg International Symposium on High Energy Gamma-Ray Astronomy

Hierarchical visual perception and two-dimensional compressive sensing for effective content-based color image retrieval

Content-based image retrieval (CBIR) has been an active research theme in the computer vision community for over two decades. While the field is relatively mature, significant research is still required in this area to develop solutions for practical applications. One reason that practical solutions have not yet been realized could be due to a limited understanding of the cognitive aspects of the human vision system. Inspired by three cognitive properties of human vision, namely, hierarchical structuring, color perception and embedded compressive sensing, a new CBIR approach is proposed. In the proposed approach, the Hue, Saturation and Value (HSV) color model and the Similar Gray Level Co-occurrence Matrix (SGLCM) texture descriptors are used to generate elementary features. These features then form a hierarchical representation of the data to which a two-dimensional compressive sensing (2D CS) feature mining algorithm is applied. Finally, a weighted feature matching method is used to perform image retrieval. We present a comprehensive set of results of applying our proposed Hierarchical Visual Perception Enabled 2D CS approach using publicly available datasets and demonstrate the efficacy of our techniques when compared with other recently published, state-of-the-art approaches

Nanoscale anisotropic plastic deformation in single crystal GaN

Elasto-plastic mechanical deformation behaviors of c-plane (0001) and nonpolar GaN single crystals are studied using nanoindentation, cathodoluminescence, and transmission electron microscopy. Nanoindentation tests show that c-plane GaN is less susceptible to plastic deformation and has higher hardness and Young's modulus than the nonpolar GaN. Cathodoluminescence and transmission electron microscopy characterizations of indent-induced plastic deformation reveal that there are two primary slip systems for the c-plane GaN, while there is only one most favorable slip system for the nonplane GaN. We suggest that the anisotropic elasto-plastic mechanical properties of GaN are relative to its anisotropic plastic deformation behavior