Nanoengineered multifunctional capsules with tailored structures and properties are of particular interest due to their multifunctions and potential applications as new colloidal structures in diverse fields. Among the available fabrication methods, the layer-by-layer (LbL) assembly of multilayer films onto colloidal particles followed by selective template removal has attracted extensive attention due to its advantages of precise control over the size, shape, composition, wall thickness and functions of the obtained capsules. The past decade has witnessed a rapid increase of research concerning the new fabrication strategies, functionalization and applications of this kind of capsules, particularly in the biomedical fields such as drug delivery, biosensors and bioreactors. In this critical review, the very recent progress of the multilayer capsules is summarized. First, the advances in assembly of capsules by the LbL technique are introduced with focus on tailoring the properties of hydrogen-bonded multilayer capsules by cross-linking, and fabrication of capsules based on covalent bonding and bio-specific interactions. Then the fabrication strategies which can speed up capsule fabrication are reviewed. In the following sections, the multi-compartmental capsules and the capsules that can transform their shape under stimulus are presented. Finally, the biomedical applications of multilayer capsules with particular emphasis on drug carriers, biosensors and bioreactors are described (306 references).

Adaptive JPEG steganographic schemes are difficult to preserve the image texture features in all scales and orientations when the embedding changes are constrained to the complicated texture regions, then a steganalysis feature extraction method is proposed based on 2 dimensional (2D) Gabor filters. The 2D Gabor filters have certain optimal joint localization properties in the spatial domain and in the spatial frequency domain. They can describe the image texture features from different scales and orientations, therefore the changes of image statistical characteristics caused by steganography embedding can be captured more effectively. For the proposed feature extraction method, the decompressed JPEG image is filtered by 2D Gabor filters with different scales and orientations firstly. Then, the histogram features are extracted from all the filtered images.Lastly, the ensemble classifier is used to assemble the proposed steganalysis feature as well as the final steganalyzer. The experimental results show that the proposed steganalysis feature can achieve a competitive performance by comparing with the other steganalysis features when they are used for the detection performance of adaptive JPEG steganography such as UED, JUNIWARD and SI-UNIWARD.

The performance decay in 2 nm-thick metal-coated silicon photoanodes for water splitting is related to the formation of a thick SiOX film at the interface, while thicker coatings live longer and degrade due to the formation of holes.

No abstract

Highly Undetectable steGO (HUGO steganography) is a well-known image steganography method proposed in recent years. The security of HUGO steganography is analyzed in this paper, and a corresponding steganalysis method is proposed based on the blind coding parameters recognition. Firstly, the principle of covert communication based on HUGO steganography and the characteristics of the Syndrome-Trellis codes (STCs) used in HUGO are analyzed; and then the potential security risk of HUGO is pointed out; Secondly, based on the idea of the blind parameters recognition for channel coding, the submatrix parameter of Multimed Tools Appl STCs is recognized correctly, and thus the message embedded by HUGO can be extracted correctly by decode algorithm of STCs. A series of experimental results show that the proposed steganalysis method can not only detect the stego-images reliably, but also extract the embedded message correctly; these validated the existence of security flaw of HUGO steganography.