Molecular modeling of post-diffusion stage of biotissue optical clearing under effect of iohexol aqueous solution

Interaction of iohexol (Omnipaque), an X-Ray contrast agent, with a mimetic peptide of collagen (GPH)3 as one of the main components of biological tissues has been studied with the use of methods of classical molecular dynamics (GROMACS). Complex molecular modeling of the post-diffusion stage of optical clearing allowed to evaluate such parameters as the average number of hydrogen bonds, formed between the clearing agent and collagen per unit time, and the immersion agent’s effect on changes in the collagen peptide volume. The obtained results are compared with similar results for glycerol, a polyatomic alcohol, and with the existing experimental data on the efficiency of optical clearing of these immersion agents.

Research on Cadmium Adsorption-Desorption Dynamics of Biochars

Biochar has high potential usage in retaining various contaminants, wastewater treatment, and water purification. In this study, three rice husk derived biochars with pyrolysis temperature 300, 400 and 500 ºC, respectively, and pristine rice rusk were used to remove cadmium from aqueous solution. The results showed that about 70% or more of Cd2+ adsorption occurred in the first 960 mins of adsorption kinetics. The Cd2+ adsorption capacity under equilibrium increased with increasing pyrolysis temperature, probably attributed to the increased specific surface area (SSA) under higher pyrolysis temperature noting that significant linear correlation occurred between Cd2+ adsorption capacity and SSA. The Cd2+ adsorption could be best fitted by pseudo-second order model relative to Elovich model and pseudo-first order model. The Cd2+ adsorption rates were higher in film diffusion stage, indicating that film diffusion stage was significant and fast in the early stage of Cd2+ adsorption. In contrast, Cd2+ adsorption by intra-particle diffusion accounted for 47.0%, 47.9% and 43.9% on average of the total Cd2+ adsorption, respectively, indicating that intra-particle diffusion of Cd2+ played a more predominant role in limiting Cd2+ adsorption rate. When reaching Cd2+ desorption equilibrium, removal ratio (RR) values were averaged 0.96, 0.91, and 0.90 under three initial concentrations. More than 90 percentage on average of Cd2+ was removed from aqueous solution by biochars and rice rusk as well, thus biochars can be used to efficiently remove contaminants from aqueous environment. Cation exchange, electrostatic attraction, and the complexation with surface functional groups could be the main dominant mechanisms for Cd2+ adsorption-desorption on biochars.

Impingement, coalescence and mixing of micro-droplets on a solid surface

The coalescence of an impinging droplet colliding with a sessile droplet at an angle(θi) is investigated by numerical simulation. The range of θi is 0° - 60° and the surface wettability are set as hydrophilic or hydrophobic, and both of them can affect the droplet mergence behavior. By using a modified mixing function, the dimensionless total mixing time τm can be calculated. The results show that there is no clear effect of θi on τm on a hydrophobic surface, while τm increases as θi increases on the hydrophilic surface. With the Weber number(We) ranging from 5.65 to 22.7 and the Ohnesorge number(Oh) ranging from 0.136 to 0.214, we find τm hardly changes with We and Oh. By dividing the mergence and mixing process in a convection and a diffusion stage, we find that the diffusion is much larger than the convection time.

On the Security of a Latin-Bit Cube-Based Image Chaotic Encryption Algorithm

In this paper, the security analysis of an image chaotic encryption algorithm based on Latin cubes and bit cubes is given. The proposed algorithm adopts a first-scrambling-diffusion- second-scrambling three-stage encryption scheme. First, a finite field is constructed using chaotic sequences. Then, the Latin cubes are generated from finite field operation and used for image chaotic encryption. In addition, according to the statistical characteristics of the diffusion image in the diffusion stage, the algorithm also uses different Latin cube combinations to scramble the diffusion image for the second time. However, the generation of Latin cubes in this algorithm is independent of plain image, while, in the diffusion stage, when any one bit in the plain image changes, the corresponding number of bits in the cipher image follows the change with obvious regularity. Thus, the equivalent secret keys can be obtained by chosen plaintext attack. Theoretical analysis and experimental results indicate that only a maximum of 2 . 5 × w × h 3 + 6 plain images are needed to crack the cipher image with w × h resolution. The size of equivalent keys deciphered by the method proposed in this paper are much smaller than other general methods of cryptanalysis for similar encryption schemes.

An Empirical Study of Smartphone User Behavior

This study investigates determinants of the adoption behavior of smartphone users. Despite the increasing number of smartphone users, the literature on information technology usage has paid little attention to the motivation behind smartphone adoption. This study identifies three determinants of smartphone adoption behavior: innovative characteristics, brand equity and social influences. Data were collected from 293 smartphone users. The analytical results have indicated that users choose to use smartphone not only for its usefulness, enjoyment and compatibility to their lifestyle (i.e. innovative characteristics), but also for its cost effectiveness (i.e. brand equity). Additionally, users will search for related information for the suitability of their adoption decisions (i.e. social influence). Together, the above factors account for over 60 percent of adoption behaviors. Moreover, the findings also indicate that perceptions of use varied over the innovation diffusion stage. Implications and suggestions for practitioners are also discussed.

An Image Encryption Algorithm with Total Diffusion

This paper proposes an image encryption algorithm which uses four scans of an image during the diffusion stage in order to achieve total diffusion between intensities of image pixels. The condition of total diffusion is fulfilled by a suitable combination of techniques of ciphertext chaining and plaintext related diffusion. The proposed encryption algorithm uses two stages which utilize chaotic logistic map for generation of pseudo-random sequences. The paper also briefly analyzes approaches described by other researchers and evaluates experimental results of the proposed solution by means of commonly used measures. Properties of our proposal regarding modifications of plain images prior to encryption or modifications of encrypted images prior to decryption are illustrated by two additional experiments. The obtained numeric results are compared with those achieved by other proposals and briefly discussed.