Image encryption based on a chaos system can effectively protect the privacy of digital images. It is said that a 3D chaotic system has a larger parameter range, better unpredictability and more complex behavior compared to low-dimension chaotic systems. Motivated by this fact, we propose a new image cryptosystem that makes use of a 3D chaotic system. There are three main steps in our scheme. In the first step, the chaotic system uses the hash value of the plaintext image to generate three sequences. In step two, one of the sequences is used to dynamically select confusion and diffusion methods, where confusion and diffusion have three algorithms, respectively, and will produce 32n (n > 100) combinations for encryption. In step three, the image is divided into hundreds of overlapping subblocks, along with the other two sequences, and each block is encrypted in the confusion and diffusion process. Information entropy, NPCR, UACI results and various security analysis results show that the algorithm has a better security performance than existing, similar algorithms, and can better resist clipping, noise, statistical analysis and other attacks.

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A series of thermo- and light-responsive copolymers of poly (N-isopropylacrylamide) (PNIPAM) and 6-[4-(4-methoxy phenyl azo)-phenoxyl-hexyl methacrylate) (AzoMA) (PNIPAM-b-PAzoMA) were synthesized via reversible addition–fragmentation chain transfer (RAFT) radical polymerization. The resulting copolymers had a narrow molecular weight distribution range of 1.06–1.24, in which Mn changed regularly with the monomer concentration. Subsequently, the diblock copolymers were successfully modified on the surface of iron oxide nanoparticles through the interaction between the chemical bonds to prepare Fe3O4@(PNIPAM-b-PAzoMA) nanoparticles. The size of fabricated nanoparticles with excellent thermo-sensitivity and photo-sensitivity was controlled at about 40–50 nm. Cell viability assays suggested that the nanoparticles showed no significant cytotoxicity and potential drug delivery in the tumor microenvironment.

Uncontrolled hemorrhage caused by trauma can easily lead to death. Efficient and safe hemostatic materials are an urgent and increasing need for hemostatic research. Following a trauma, wound healing is induced by various cellular mechanisms and proteins. Hemostatic biomaterials that can not only halt bleeding quickly but also provide an environment to promote wound healing have been the focus of research in recent years. Mussel-inspired nanoparticle composite hydrogels have been propelling the development of hemostatic materials owing to their unique advantages in adhesion, hemostasis, and bacteriostasis. This review summarizes the hemostatic and antimicrobial fundamentals of polydopamine (PDA)-based nanomaterials and emphasizes current developments in hemorrhage-related PDA nanomaterials. Moreover, it briefly discusses safety concerns and clinical application problems with PDA hemostatic nanomaterials.

The mechanism of the photocatalytic reaction of defective ZnO systems was determined.