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Syndrome-trellis codes (STCs) are commonly used in image steganographic schemes, which aim at minimizing the embedding distortion, but most distortion models cannot capture the mutual interaction of embedding modifications (MIEMs). In this article, a secure halftone image steganographic scheme based on a feature space and layer embedding is proposed. First, a feature space is constructed by a characterization method that is designed based on the statistics of 4 x 4 pixel blocks in halftone images. Upon the feature space, a generalized steganalyzer with good classification ability is proposed, which is used to measure the embedding distortion. As a result, a distortion model based on a hybrid feature space is constructed, which outperforms some state-of-the-art models. Then, as the distortion model is established on the statistics of local regions, a layer embedding strategy is proposed to reduce MIEM. It divides the host image into multiple layers according to their relative positions in 4 x 4 blocks, and the embedding procedure is executed layer by layer. In each layer, any two pixels are located at different 4 x 4 blocks in the original image, and the distortion model makes sure that the calculation of pixel distortions is independent. Between layers, the pixel distortions of the current layer are updated according to the previous embedding modifications, thus reducing the total embedding distortion. Comparisons with prior schemes demonstrate that the proposed steganographic scheme achieves high statistical security when resisting the state-of-the-art steganalysis.

Utilizing statistical models of binary images is a common and effective means to steganalyze binary images, and the design of the statistical model is essential to the performance of steganalysis. In this paper, we propose a new model based on a histogram of pixel structuring elements (SEs), which is a suitable representation of a binary image for the task of steganalysis. The texture property and the dependency among pixels are considered inside the SEs. The SEs with different patterns will be evaluated comprehensively according to a statistical criterion, and some of them will be selected to construct the feature set for training the steganalyzer. The distributions of these selected SEs, which contain many highly flippable pixels, will be emphasized by the criterion, and they can reflect the difference between cover images and stego-images. Finally, a series of experiments are conducted on two datasets, and the results show that the proposed scheme significantly outperforms state-of-the-art schemes.

A facile and versatile route to fabricate photoluminescent and robust superhydrophobic dual-functional paper was reported. The approach was based on lanthanide-based nanocrystal/nanotitania-doped c...

Rare earth elements (REEs) are applied in various industries. They have entered the environment through different pathways and caused serious pollutions. So far, due to the lack of calculated toxicity coefficient of rare earth elements, it is still difficult to evaluate their ecological risks. The potential ecological risk index method is commonly used in the pollution assessment of heavy metals. And rare earth elements are similar to heavy metals. Herein, we used this method to calculate the toxicity coefficient of 15 rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y). The calculation was based on two principles, rare earth elements coexist with each other because of their similar chemical properties, and the elemental abundance and release effect determine their toxicity. The results are as follows: La = 1, Ce = 1, Pr = 5, Nd = 2, Sm = 5, Eu = 10, Gd = 5, Tb = 10, Dy = 5, Ho = 10, Er = 5, Tm = 10, Yb = 5, Lu = 20, Y = 2. Our results can provide a reference to the potential ecological risk assessment of rare earth elements.

Herein, an eco-friendly and straightforward method was provided for the fabrication of superhydrophobic paper from native wood cellulose fibers via in situ hydrolysis of tetraethyl titanate(IV) without any chemical pretreatment. By simply adjusting the amount of acetic acid (HAc), the surface micro/nanomorphology could be well controlled. After papermaking and hexadecyltrimethoxysilane modification, superhydrophobic paper can be easily achieved with static water contact angle of 152.3° (± 1.3°). The paper also possessed good self-cleaning property against contamination and durability toward mechanical damages of finger wiping over 50 cycles as well as excellent oil/water separation, which expands its utility in various paper-based technologies. The whole procedure possesses the advantages of friendly raw material, mild reaction conditions and with no toxic modifier, which hold potential application in cellulose-based superhydrophobic material in large scale.

Ion concentration changes significantly under stress conditions such as chilling. Accurate assessment of the concentration, flow velocity and flow direction of ions is pivotal to understanding the mechanism of stress response of fruits and vegetables. Fibroin is a newly reported edible coating material effective in delaying fruit senescence and alleviating chilling injury. In the present study, banana fruit were fibroin-treated before cold-stored, and non-invasive micro-test technology (NMT) was employed to determine H+ and Ca2+ fluxes across the non-wound surfaces of pericarp cuboids of the fibroid-treated banana fruit. When the wound surfaces of banana pericarp cuboids were coated with food grease, H+ and Ca2+ fluxes across the wound surfaces fluctuated around 0 nmol m−2 s-1, indicating that ion flow across the wound surfaces of the pericarp cuboids had been completely prevented by food grease coating. This coating method was employed to coat the wound surfaces while H+ and Ca2+ fluxes across the normal surfaces of the pericarp cuboids of fibroin-treated cold-stored banana fruit were determined. The results suggested that fibroin treatment alleviated chilling injury by reducing H+ and Ca2+ effluxes. Utilization of food grease coating on wound surfaces will greatly improve our ability to reveal the mechanism of chilling injury in fruits and vegetables by learning ion fluxes in tissues and organs.

Lignification is especially prominent in postharvest pumelo fruit, which greatly impairs their attractiveness and commercial value. This study investigated the energy metabolism and lipid peroxidation and their relationship with accumulated lignin content in juice sacs of &ldquo, Hongroumiyou&rdquo, (HR) during 90 d of storage at 25 &deg, C. The results indicated that, the alterations of energy metabolism in juice of sacs of postharvest pumelos was featured by a continuous decline in energy charge and ATP/ADP, an increase in succinic dehydrogenase (SDH) activity before 30 d and increases in activities of cytochrome c oxidase (CCO) and F0F1-ATPase before 60 d, but declines in activities of Ca2+-ATPase and H+-ATPase. Additionally, enhanced contents of H2O2, O2&minus, and &ndash, OH scavenging rate, increased malondialdehyde (MDA) content, and transformation of unsaturated fatty acids (USFA) to saturated fatty acids (USFA) and reduced USFA/SFA (U/S) could result in lipid peroxidation and membrane integrity loss. Moreover, correlation analysis showed that lignin accumulation was in close relation to energy metabolism and lipid peroxidation in juice sacs of postharvest pumelos. These results gave evident credence for the involvement of energy metabolism and lipid peroxidation in the lignin accumulation of HR pumelo fruit during postharvest storage.

Chilling injury is especially prominent in postharvest bananas stored at low temperature below 13 &deg, C. To elucidate better the relationship between cell membrane lipids and chilling injury, an untargeted lipidomics approach using ultra-performance liquid chromatography&ndash, mass spectrometry was conducted. Banana fruit were stored at 6 &deg, C for 0 (control) and 4 days and then sampled for lipid analysis. After 4 days of storage, banana peel exhibited a marked chilling injury symptom. Furthermore, 45 lipid compounds, including glycerophospholipids, saccharolipids, and glycerolipids, were identified with significant changes in peel tissues of bananas stored for 4 days compared with the control fruit. In addition, higher ratio of digalactosyldiacylglycerol (DGDG) to monogalactosyldiacylglycerol (MGDG) and higher levels of phosphatidic acid (PA) and saturated fatty acids but lower levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and unsaturated fatty acids were observed in banana fruit with chilling injury in contrast to the control fruit. Meanwhile, higher activities of phospholipase D (PLD) and lipoxygenase (LOX) were associated with significantly upregulated gene expressions of MaPLD1 and MaLOX2 and higher malondialdehyde (MDA) content in chilling injury-related bananas. In conclusion, our study indicated that membrane lipid degradation resulted from reduced PC and PE, but accumulated PA, while membrane lipid peroxidation resulted from the elevated saturation of fatty acids, resulting in membrane damage which subsequently accelerated the chilling injury occurrence of banana fruit during storage at low temperature.

Lignification, which occurs in many horticultural fruit and vegetables, brings about undesirable texture and unfavorable consumer preference. However, this problem has rarely been studied. In this work, three pumelo cultivars cvs &ldquo, Hongroumiyou&rdquo, (HR), &ldquo, Bairoumiyou&rdquo, (BR), and &ldquo, Huangroumiyou&rdquo, (HuR) were stored at 25 &deg, C for 90 days, and juice sacs were sampled to explore the lignin accumulation and its relationship to sucrose and energy depletion were investigated. The results displayed that HuR contained lower sucrose content, lower ATP level, but higher lignin content compared to BR and HR during postharvest storage, indicating that the sequence according to storage resistance on the basis of lignin content is as follows: HuR &lt, BR &lt, HR. Furthermore, sucrose degradation attributed to enhanced activities of neutral invertase (NI), soluble acid invertase (S-AI), cell wall-bound invertase (B-AI), and energy deficit on account of declined ATP level, showed significantly negative correlation with lignin accumulation, suggesting that lignin accumulation occurrence could induce sucrose degradation and energy deficit during postharvest storage. Additionally, higher activities of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD) could accelerate lignin synthesis and resulted in lignin accumulation during postharvest pumelo storage.

A binary image steganalysis scheme based on the statistic model of local residual pattern (LRP) is proposed in this paper. LRP means the pattern of a local area of the residual map of the binary image, which is calculated with the XOR operation. The XOR operation is sensitive to the difference between adjacent pixels, which leads to the emphasis on edge property of the residual map. The neighbouring LRPs of the modified pixel will be affect, which makes the statistic model of LRPs change. Thus the trace of steganography can be detected according to the difference between the statistic models. Finally, the experiments we conducted show that our proposed scheme is effective on binary image steganalysis.

The knowledge of solid-liquid equilibrium data and solution thermodynamics of 2,2,2-trichloroacetamide (TCAcAm) in different solvents are essential for its synthesis, purification and further theoretical studies. In this paper, the solubility of TCAcAm in fifteen mono solvents of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, 2-butanone, acetone, ethyl acetate, 2-pentanone, acetonitrile, methyl acetate and ethyl formate was obtained through a gravimetric method at the temperature from 272.15 to 324.15 K under ambient pressure. The mole fraction solubility of TCAcAm in mono solvents showed an increasing trend with increasing temperature, and the phase equilibrium data in ketones and esters was much larger than that in alcohols. The experimental solubility can be well correlated using several thermodynamic models, such as the modified Apelblat equation, λh equation, non-random two-liquid (NRTL) model and the Wilson model. The obtained maximum relative average deviation (RAD) and root-mean-square deviation (RMSD) were 6.02 × 10−3 and 2.086 × 10−3 respectively. Besides, the dissolution enthalpy, entropy, and Gibbs free energy were calculated on the basis of thermodynamic relations and the Wilson model, which revealed that the dissolution of TCAcAm was a spontaneous and endothermic process.

The work presented herein focuses on simulating the compounding process via a torque rheometer, as well as the relationship between the melt viscosity and the polymer molecular weight (MW). We aim to predict the plasticization of polylactic acid (PLA) using polypropylene glycol (PPG) with different MWs. The rheological properties of the PLA/PPG composites containing PPG with different MWs were systematically studied by capillary rheometry and torque rheometry. The initial degradation of PLA/PPG composites during melt processing was monitored in real time. The results indicate that PPG can significantly reduce the melt viscosity of PLA/PPG composites, leading to obvious pseudoplastic fluid behavior. The lower the MW of PPG, the lower the viscosity of the PLA/PPG composite. The addition of PPG was favorable for the degradation of PLA during processing, and the degradation degree of the composite materials increased as the MW of PPG was decreased.

Insights into high temperature oxidation of Al2O3-forming Ti3AlC2 are made to understand the sub-parabolic oxidation rate and the absence of Al-depletion zone beneath the protective Al2O3 scale. The scale results from selective oxidation of Al that migrated from Ti3AlC2 according to Ti3AlC2 + 3/2y O-2 -> Ti3Al1-yC2 + 1/2y Al2O3, leaving Al vacancy in the substrate. Inward diffusion of oxygen via grain boundaries of the Al2O3 scale predominates for the scale growth. The Al2O3 grains grow with time, yielding sub-parabolic oxidation kinetics. The Al diffuses in a fast manner, accounting for the absence of Al-depletion zone. (C) 2012 Elsevier Ltd. All rights reserved.