Quantum Watermarking Using Entanglement Swapping

Digital watermarking is the process of embedding information into a digital signal in a way that is difficult to remove. In this article a secure quantum watermarking using entanglement swapping is proposed. Here the entanglement swapping is employed to build up a hidden layer of secure message under the conventional first layer of secure information sequence. In this protocol by insuring the security of transmission of the first layer of information sequence the security of the hidden secret messages is also proved to be reliable regardless of whether the hidden channel has been detected or not.     

Specific adhesion of vesicles to compliant bio-adhesive substrates

Cell behavior is mediated by variety of physiochemical properties of the extracellular matrix (ECM). Mechanical stiffness of ECM, in particular, is found to be a major regulator for the multiple aspects of cellular function. Experiments show that cells generally exhibit an apparent adhesion preference for stiffer substrates. The effect of substrate elasticity is also found to be strongly coupled with adhesivity of the substrate. To understand the underlying physics of rigidity sensing mechanism in cells, in this study we use a vesicle-substrate system to model cell adhesion as a first order approximation. Within this framework, an equilibrium thermodynamic analysis is undertaken to elucidate the interplay between substrate compliance and equilibrium configuration of an adherent vesicle. The equilibrium adhesion is assumed to ensure minimization of the free energy contributed by substrate deformation and interfacial adhesive and repulsive interactions between the membrane and substrate. The predictions of this purely mechanistic model are found to be qualitatively analogous to some of the characteristic features of cell adhesion to compliant bio-adhesive substrates. This observation suggests that the physical aspects of the membrane–substrate interfacial interactions could passively contribute in regulation of the rigidity sensing by cells.     

Practical reduction of imines by NaBH4/alumina under solvent-free conditions： An efficient route to secondary amine

Sodium borohydride supported on alumina reduces imines to the corresponding secondary amines in high to excellent isolated yields under solvent-free conditions. Noteworthy is that highly chemoselective reactions were achieved in the presence of other functional groups such as halogen, nitro, and cyano groups.     

A Novel LSB Based Quantum Watermarking

Quantum watermarking is a technique which embeds the invisible quantum signal such as the owners identification into quantum multimedia data (such as audio, video and image) for copyright protection. In this paper, using a quantum representation of digital images a new quantum watermarking protocol including quantum image scrambling based on Least Significant Bit (LSB) is proposed. In this protocol, by using m-bit embedding key K₁ and m-bit extracting key K₂ a m-pixel gray scale image is watermarked in a m-pixel carrier image by the original owner of the carrier image. For validation of the presented scheme the peak-signal-to-noise ratio (PSNR) and histogram graphs of the images are analyzed.     

A New Quantum Gray-Scale Image Encoding Scheme

In this paper, a new quantum images encoding scheme is proposed. The proposed scheme mainly consists of four different encoding algorithms. The idea behind of the scheme is a binary key generated randomly for each pixel of the original image. Afterwards, the employed encoding algorithm is selected corresponding to the qubit pair of the generated randomized binary key. The security analysis of the proposed scheme proved its enhancement through both randomization of the generated binary image key and altering the gray-scale value of the image pixels using the qubits of randomized binary key. The simulation of the proposed scheme assures that the final encoded image could not be recognized visually. Moreover, the histogram diagram of encoded image is flatter than the original one. The Shannon entropies of the final encoded images are significantly higher than the original one, which indicates that the attacker can not gain any information about the encoded images.     

Penta-SiC5 monolayer: A novel quasi-planar indirect semiconductor with a tunable wide band gap

In this paper, by using of the first principles calculations in the framework of the density functional theory, we systematically investigated the structure, stability, electronic and optical properties of a novel two-dimensional pentagonal monolayer semiconductors namely penta-SiC₅ monolayer. Comparing elemental silicon, diamond, and previously reported 2D carbon allotropes, our calculation shows that the predicted penta-SiC₅ monolayer has a metastable nature. The calculated results indicate that the predicted monolayer is an indirect semiconductor with a wide band gap of about 2.82 eV by using Heyd–Scuseria–Ernzerhof (HSE06) hybrid functional level of theory which can be effectively tuned by external biaxial strains. The obtained exceptional electronic properties suggest penta-SiC₅ monolayer as promising candidates for application in new electronic devices in nano scale.     

Penta-P<Subscript>2</Subscript>X (X=C,Si) monolayers as wide-bandgap semiconductors: A first principles prediction

By means of density functional theory computations, we predicted two novel two-dimensional (2D) nanomaterials, namely P₂X (X=C, Si) monolayers with pentagonal configurations. Their structures, stabilities, intrinsic electronic, and optical properties as well as the effect of external strain to the electronic properties have been systematically examined. Our computations showed that these P₂C and P₂Si monolayers have rather high thermodynamic, kinetic, and thermal stabilities, and are indirect semiconductors with wide bandgaps (2.76 eV and 2.69 eV, respectively) which can be tuned by an external strain. These monolayers exhibit high absorptions in the UV region, but behave as almost transparent layers for visible light in the electromagnetic spectrum. Their high stabilities and exceptional electronic and optical properties suggest them as promising candidates for future applications in UV-light shielding and antireflection layers in solar cells.     

High diffraction efficiency in SBN with applied fields near the coercive field

We present the experiments and results of our investigation of electrical fixing in SBN:60. We propose an optical method for determining the value of the coercive field in ferroelectric crystals. An interferometric method is used to map the change in the index of refraction with negative applied fields, where the minimum of the index change is an indication of the coercive field. From this experiment, values of 1.55 kV±20 V for the coercive voltage and 147±6 pm/V for the linear electro-optic coefficient are found. Two electrical-fixing techniques that result in very high diffraction efficiencies are presented, discussed and compared to previous publications on electrical fixing in SBN. High diffraction efficiencies of about 95% were achieved with the application of negative fields near the coercive region, during and after holographic recording in the crystal. Received: 6 December 2000 / Revised version: 13 February 2001 / Published online: 27 April 2001     

Molecularly imprinted polymer in microextraction by packed sorbent for the simultaneous determination of local anesthetics: lidocaine,ropivacaine, mepivacaine and bupivacaine in plasma and urine samples

This study presents the use of molecularly imprinted polymer (MIP) as packing material for microextraction by packed syringe (MEPS) to achieve higher extraction selectivity. Pentycaine was used as template for MIP. Development and validation of the determination of lidocaine, ropivacaine, mepivacaine and bupivacaine in human plasma and urine samples utilizing MIP‐MEPS and liquid chromatography–tandem mass spectrometry (LC‐MS/MS) were carried out. The MEPS MIP‐cartridge could be used for 100 extractions before it was discarded. The extraction recovery ranged from 60 to 80%. The correlation coefficients values were >0.999 for all assays using lidocaine, ropivacaine, mepivacaine and bupivacaine in the calibration range 5–2000 nmol/L. The accuracy of the studied compounds, given as a percentage variation from the nominal concentration values, ranged from ‐4.9 to 8.4% using plasma and urine samples. The between‐batch precision, given as the relative standard deviation, at three different concentrations (quality control samples) was ranged from ?4.7 to 14.0% and from 1.8 to 12.7% in plasma and urine, respectively. The lower limit of quantification and limit of detection of the studied substances were 5.0 and 1.0 nm , respectively. Copyright © 2013 John Wiley & Sons, Ltd.     

Direct Numerical Simulation of Pore-Scale Trapping Events During Capillary-Dominated Two-Phase Flow in Porous Media

Transport in Porous Media - This study focuses on direct numerical simulation of imbibition, displacement of the non-wetting phase by the wetting phase, through water-wet carbonate rocks. We...