A pattern recognition system for JPEG steganography detection

This paper builds up a pattern recognition system to detect anomalies in JPEG images, especially steganographic content. The system consists of feature generation, feature ranking and selection, feature extraction, and pattern classification. These processes tend to capture image characteristics, reduce the problem dimensionality, eliminate the noise inferences between features, and further improve classification accuracies on clean and steganography JPEG images. Based on the discussion and analysis of six popular JPEG steganography methods, the entire recognition system results in higher classification accuracies between clean and steganography classes compared to merely using individual feature subset for JPEG steganography detection. The strength of feature combination and preprocessing has been integrated even when a small amount of information is embedded. The work demonstrated in this paper is extensible and can be improved by integrating various new and current techniques.     

Manifestation of the Gouy phase in vector-vortex beams

Experimental measurements of the twirl and changes in the anisotropy of the constant intensity ellipse, and the rotation of the polarization singular lemon pattern a generalized vector-vortex beam experiences around the two foci due to the converging and diverging conical waves and in between, are presented and interpreted as being due to the universal form of the Gouy phase, φ(G)=mπ/2.     

Hilbert reconstruction of phase-shifted second-harmonic holographic images

New techniques are presented that make phase-shifting holography viable for second-harmonic generation (SHG) holography with weak object fields. We developed an intrinsic phase shift calibration of SHG holograms, an algorithm that extracts the reference and object intensity directly from a set of phase-shifted holographic data, and a more robust phase-shifting holography reconstruction algorithm based on π-shifted hologram pairs that permits self-calibration of the phase shift and recovery of the complex field through a Hilbert transform.     

Spectroscopic analysis of immobilised redox enzymes under direct electrochemical control

This article reviews recent developments in spectroscopic analysis of electrode-immobilised enzymes under direct, unmediated electrochemical control. These methods unite the suite of spectroscopic methods available for characterisation of structural, electronic and coordination changes in proteins with the exquisite control over complex redox enzymes that can be achieved in protein film electrochemistry in which immobilised protein molecules exchange electrons directly with an electrode. This combination is particularly powerful in studies of highly active enzymes where redox states can be controlled even under fast electrocatalytic turnover. We examine examples in which UV-visible, IR, Raman and MCD spectroscopy have been combined with direct electrochemistry to probe redox-dependent chemistry, and consider future opportunities for 'direct' spectroelectrochemistry of immobilised enzymes.     

CH(4) storage and CO(2) capture in highly porous zirconium oxide based metal-organic frameworks

A series of porous Zr oxoclusters-based MOFs was computationally explored for their gas storage/capture performances. The highly porous UiO-67(Zr) and UiO-68(Zr) solids show exceptionally high CH(4) and CO(2) adsorption capacities under operating conditions that make these thermal, water and mechanical resistant materials very promising for physisorption-based processes.     

Sulfonato-encapsulated bismuth(III) oxido-clusters from Bi2O3 in water under mild conditions

Treatment of Bi(2)O(3) with the acids; S-(+)-10-camphorsulfonic, 2,4,6-mesitylenesulfonic and sulfamic, under sonication at room temperature in water for 2-4 h, results in the formation and subsequent crystallisation of polynuclear bismuth oxido-clusters; [Bi(18)O(12)(OH)(12)(O(3)S-Cam)(18)(H(2)O)(2)], [Bi(38)O(45)(O(3)S-Mes)(24)(H(2)O)(14)] and [Bi(6)O(4)(OH)(4)(O(3)SNH(2))(6)].     

Synthesis and preliminary investigations of the siRNA delivery potential of novel, single-chain rigid cationic carotenoid lipids

The success of nucleic acid delivery requires the development of safe and efficient delivery vectors that overcome cellular barriers for effective transport. Herein we describe the synthesis of a series of novel, single-chain rigid cationic carotenoid lipids and a study of their preliminary in vitro siRNA delivery effectiveness and cellular toxicity. The efficiency of siRNA delivery by the single-chain lipid series was compared with that of known cationic lipid vectors, 3β-[N-(N',N'-dimethylaminoethane)carbamoyl]-cholesterol (DC-Chol) and 1,2-dimyristoyl-sn-glyceryl-3-phosphoethanolamine (EPC) as positive controls. All cationic lipids (controls and single-chain lipids) were co-formulated into liposomes with the neutral co-lipid, 1,2-dioleolyl-sn-glycerol-3-phosphoethanolamine (DOPE). Cationic lipid-siRNA complexes of varying (+/-) molar charge ratios were formulated for delivery into HR5-CL11 cells. Of the five single-chain carotenoid lipids investigated, lipids 1, 2, 3 and 5 displayed significant knockdown efficiency with HR5-CL11 cells. In addition, lipid 1 exhibited the lowest levels of cytotoxicity with cell viability greater than 80% at all (+/-) molar charge ratios studied. This novel, single-chain rigid carotenoid-based cationic lipid represents a new class of transfection vector with excellent cell tolerance, accompanied with encouraging siRNA delivery efficiency.     

Polymer-supported syntheses of thiophene-containing compounds using a new type of traceless linker

A new type of traceless linker is described for use in polymer-supported (PS) syntheses of thiophene-containing compounds. It is based on the cleavage of PS aryl 2-thienyl ketones by a mixture of potassium t-butoxide and water (typical mol ratio 10:3) in an ethereal solvent. Cleavage occurs to give the soluble thiophene-containing product. The method is used to prepare a range of eight thiophene-containing compounds including a terthiophene and a dialkylquaterthiophene. PS unsymmetrical diaryl ketones incorporating, for example, ortho-methoxyphenyl or pyrrole moieties could also serve as traceless linkers.