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This paper proposes a fractional-order chaotic system using a tri-stable locally active memristor. The characteristics of the memristor, dynamic mechanism of oscillation, and behaviors of the proposed system were analyzed, and then a visually meaningful image encryption scheme was designed based on the chaotic system, DNA encoding, and integer wavelet transform (IWT). Firstly, the mathematical model of the memristor was designed, which was nonvolatile, locally active, and tri-stable. Secondly, the stability, dynamic mechanism of oscillation, bifurcation behaviors, and complexity of the fractional-order memristive chaotic system were investigated and the conditions of stability were obtained. Thirdly, the largest Lyapunov exponent, bifurcation diagram, and complexity of the novel system were calculated and the coexisting bifurcation, coexisting attractors, spectral entropy, and so on are shown. Finally, a visually meaningful image encryption scheme based on the proposed system was designed, and its security was assessed by statistical analysis and different attacks. Numerical simulation demonstrated the effectiveness of the theoretical analysis and high security of the proposed image encryption scheme. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Raman spatial resolution was improved by close to 20% compared with confocal Raman microscopy, based on the Raman image subtraction method. • The axial focusing capability is estimated to be ∼2 nm, enabling accurate focus tracking and high spatial resolution topographic imaging. • In situ topographic imaging and Raman mapping ability with high spatial resolution and stability under homologous excitation. • Easy to implement, owing to the lack of intricate equipment adjustments or signal demodulation required. Confocal Raman microscopy (CRM) is widely used in various fields because it provides topography and molecular fingerprint information on delicate structures in a non-destructive and label-free manner. However, CRM's limited spatial resolution and focusing stability have impeded its observation capabilities for finer structures. This paper proposes a differential confocal Raman image subtraction microscopy (DCRISM) method to address the issues above. This method improves spatial resolution by weighted subtraction of Raman images acquired from two pinholes of different sizes. Concurrently, differential confocal technology is employed to provide axial focus tracking, guaranteeing the stability of the focus during the imaging process. Compared to traditional CRM, the Raman spatial resolution is improved by about 19.5 % and 18.4 % in the lateral and axial directions, with an axial focusing capability of 2 nm. These results facilitate the application of CRM to the measurement of microstructures with dimensions approaching or even exceeding the diffraction limit. [ABSTRACT FROM AUTHOR]

• A unique glycosaminoglycan (SGAG) was purified from the cultured snail. • SGAG is a structural regular GAG without anticoagulant activity. • SGAG accelerated the healing of full-thickness wounds in diabetic mice. • SGAG alleviated the inflammation and dermal edema in early stage and promoted angiogenesis. Diabetic foot ulcer (DFU) is a common high-risk complication in patients with diabetes mellitus, but current drugs and therapies in management of this disease cannot meet the urgent clinical needs. In this study, a snail glycosaminoglycan (SGAG) from the cultured China white jade snail was purified and structurally clarified. This snail glycosaminoglycan is a regular sulfated polysaccharide, composed of iduronic acid (IdoA) and N-acetyl-glucosamine (GlcNAc) with the repeating sequence of →4)-α-GlcNAc (1→4)-α-IdoA2S (1→. The biological assays showed that SGAG had no anticoagulant activity for lacking specific heparin pentasaccharide sequence. The pharmacological experiments suggested that SGAG markedly accelerated the healing of full-thickness wounds in diabetic mice skin. Histologic and immunohistochemical analysis revealed that SGAG treatment alleviated the inflammation and dermal edema, and promoted angiogenesis. This is the first report applying the snail glycosaminoglycan to favor diabetic wound healing. [ABSTRACT FROM AUTHOR]

To investigate the influence of alkali and alkaline earth metals (AAEMs: K, Na, Ca, and Mg) on the co-pyrolysis of municipal solid waste (MSW) and biomass briquettes (CSBs), the pyrolysis properties and products distribution for the blends of pretreated CSBs and MSW were studied by thermogravimetric analysis with Fourier-transform infrared spectroscopy under N2 and CO2 atmospheres. Results showed that the AAEM salts were effective at reducing the initial temperature during pyrolysis process. The presence of AAEM salts inhibited the volatile release rate of the first pyrolysis stage of the blend, while the alkali and alkaline earth salts separately enhanced the volatile release rates of the second and third pyrolysis stages under both atmospheres. Replacement of N2 with CO2 caused lower residual masses of the blend, which were further reduced by the catalytic effect of the AAEM salts. The CO2 yields were enhanced by adding AAEM salts under the N2 atmosphere. Ca had the most obvious catalytic effect on the CO production in the third pyrolysis stage. Different AAEM salts added to the samples displayed different effects on the emissions of alkyl and carbonyl groups. [ABSTRACT FROM AUTHOR]