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Alkali-activated concretes (AACs) are attracting increasing attention due to their potential as alternatives to ordinary Portland cement concrete (OPCC). This paper is a holistic review of current research on the mechanical properties of AAC including research on its compressive strength, tensile strength, elastic modulus, Poisson's ratio, stress-strain relationship under uniaxial compression, fracture properties, bond mechanism with steel reinforcement, dynamic mechanical properties, and high-temperature performance. Three types of AAC are reviewed: alkali-activated slag, alkali-activated fly ash, and alkali-activated slag-fly ash concretes. The applicability to AAC of design formulas found in codes of practice that were developed to estimate the basic mechanical performances of OPCC is also discussed. It is shown that, in general, AAC exhibits better bond performance with steel reinforcement and better strength performance after exposure to elevated temperatures than OPCC. For the other reviewed mechanical properties, the differences between AAC and OPCC largely depend on the proportions of raw materials in the concrete; specifically, the slag to fly ash ratio may be a very influential factor. As there is a trend to combine slag and fly ash in the production of AAC to achieve normal temperature curing and environmental friendliness, further research is deemed necessary to determine how the slag to fly ash ratio influences the fundamental mechanical properties of AAC and how this affects practical designs.

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The development of wound dressings with combined antibacterial activities and pro-healing functions has always been an intractable medical task for treating bacterial wound infection. Herein, a novel injectable hybrid hydrogel dressing is developed, which is doped with nitric oxide (NO) donor (N,N'-di-sec-butyl-N,N'-dinitroso-1,4-phenylenediamine, BNN6) loaded two-dimensional polydopamine nanosheets (PDA NS). The hydrogel matrix is in situ formed through dynamic Schiff base crosslinking between hydrazide-modified 𝜸-polyglutamic acid (𝜸-PGA-ADH) and aldehyde-terminated Pluronic F127 (F127-CHO). Under 808 nm irradiation, the embedded PDA NS exhibits outstanding photothermal transform properties (56.1%) and on-demand NO release. The combination of photothermal and NO gas therapy with a synergistic antibacterial effect works on both Escherichia coli and Staphylococcus aureus in vitro. Furthermore, a full-thickness skin defect model also demonstrates that the hybrid hydrogel shows outstanding antibacterial properties and effectively accelerates the wound healing process. Overall, this study provides a facile and promising method for the fabrication of PDA NS based multifunctional hydrogel dressing for the application of infectious skin wound healing.

The Chinese giant salamander Andrias davidianus is the largest living amphibian. Most wild populations are threatened and some are already extinct. The Chinese government has declared the species a Class II Protected Species, and it is listed as Critically Endangered in the Chinese Red Book of Amphibians and Reptiles and as Data Deficient on the IUCN Red List. Populations of the species have declined sharply in both range and number since the 1950s because of habitat loss and fragmentation, and hunting for the commercial luxury food trade. Remaining populations appear to be distributed in 12 areas across 17 provinces in the mountainous areas of the middle Yangtze, Yellow and Pearl Rivers. Since the 1980s, 14 nature reserves, with a total area of more than 355,000 ha, have been established for the conservation of the Chinese giant salamander. We carried out habitat and questionnaire surveys for the species in 13 locations, and based on the results and on the little amount of published information, most of it in Chinese, we assess the current status of the species and make recommendations for its conservation management. Conservation of the Chinese giant salamander should be given a high priority and considered an important part of wetland management.

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An enzyme-responsive nanoplatform was fabricated on Ti substrates to treat implant-associated bacterial infection and accelerate tissue growth in vivo.