Adaptive Chaotic Image Encryption Algorithm Based on RNA and Pixel Depth

To prevent the leakage of image content, image encryption technology has received increasing attention. Most current algorithms are only suitable for the images of certain types and cannot update keys in a timely manner. To tackle such problems, we propose an adaptive chaotic image encryption algorithm based on RNA and pixel depth. Firstly, a novel chaotic system, two-dimensional improved Logistic-adjusted-Sine map is designed. Then, we propose a three-dimensional adaptive Arnold transform for scrambling. Secondly, keys are generated by the hash values of the plain image and current time to achieve one-image, one-key, and one-time pad simultaneously. Thirdly, we build a pre-permuted RNA cube for 3D adaptive scrambling by pixel depth, chaotic sequences, and adaptive RNA coding. Finally, selective diffusion combined with pixel depth and RNA operations is performed, in which the RNA operators are determined by the chemical structure and properties of amino acids. Pixel depth is integrated into the whole procedure of parameter generation, scrambling, and diffusion. Experiments and algorithm analyses show that our algorithm has strong security, desirable performance, and a broader scope of application.

Atom-molecule conversion with quantum manipulations

In this paper, we investigate quantum manipulations in an open atom-molecule conversion system. Through the transformation for the basis of the system, a set of time-dependent equations are derived under mean field approximation. We find that transitions between different dynamic areas of the system can be realized through manipulating an external rotating magnetic field, which corresponds to the tunneling rate in the equation. Through investigating the phase space of the system, we design an efficient method to combine pure cold molecule and pure molecular state so that it can be reached with much shorter time. Furthermore, manipulation of laser signal modulation, external diving and the distance-selective diffusion are also discussed in this paper.

An Envelope Protein of a Prokaryotic Organelle Function towards Conserving Catalytic Activity of the Native Enzyme at Higher Temperatures

A classic example of an all-protein natural nano-bioreactor, the bacterial microcompartments are a special kind of prokaryotic organelles that confine enzymes within a small volume enveloped by an outer layer of shell proteins. This arrangement provides conditional metabolic aid to the bacteria. The outer shell allows selective diffusion of small molecules and sequesters toxic metabolites. In this work we use 1,2-propanediol utilization microcompartment as a model to study the effect of molecular confinement on the stability and catalytic activity of native enzymes in microcompartment. We observe a 50% decrease in the activity of free enzyme PduCDE at 45°C, while PduMCP retains its optimum activity till 50°C followed by more than 40% reduced activity at 55°C. PduBB’, the major component of the outer shell contributes to the increased catalytic activity of PduCDE. PduBB’ also prevents the unfolding and aggregation of PduCDE under thermal stress. Using a combination of experimental and theoretical studies we probe the interactions of the shell proteins PduBB’, N-terminal truncated PduB and single mutant PduB’M38L with PduCDE. We observe that all the three variants of PduB* shell proteins interact with the enzyme in vitro, but only PduBB’ influences its activity and stability, underscoring the significance of the unique combination of PduB and PduB’ in PduMCP assembly.