Fractional order calculus can represent systems with high-order dynamics and complex nonlinear phenomena using few coefficients, since the arbitrary order of the derivatives provides an additional degree of freedom to...Fractional order calculus can represent systems with high-order dynamics and complex nonlinear phenomena using few coefficients, since the arbitrary order of the derivatives provides an additional degree of freedom to fit a specific behavior. Numerous mathematicians have contributed to the history of fractional calculus by attempting to solve a fundamental problem to the best of their understanding. Each researcher sought a definition and therefore different approaches, which has led to various definitions of differentiation and anti-differentiation of non-integer orders that are proven equivalent. Although all these definitions may be equivalent, from one specific standpoint, i.e., for a specific application, some definitions seem more attractive. Furthermore, it is well known that food gums are complex carbohydrates that can suit for a wide variety of functions in the context of food engineering. The viscoelastic behavior of food gums is crucial for these applications and formulations of new or improved food products. Small progress has been made to understand the viscoelastic behavior of food gums and there are few studies in the literature about these models. In this paper, we applied the Riemann-Liouville approach and the Fourier transform in order to obtain numerical simulations results of a fractional derivative model based on previous literature that to make a quantitative description of the viscoelastic properties behavior for a food gum. The results reveal that the fractional model shows good simulation capability and can be an attractive means for predicting and to elucidate the dynamic viscoelastic behavior of food gums.展开更多
Most commonly used wound dressings have severe problems,such as an inability to adapt to wound shape or a lack of antibacterial capacity,affecting their ability to meet the requirements of clinical applications.Here,a...Most commonly used wound dressings have severe problems,such as an inability to adapt to wound shape or a lack of antibacterial capacity,affecting their ability to meet the requirements of clinical applications.Here,a nanocomposite hydrogel(XKP)is developed by introducing polydopamine nanoparticles(PDA NPs)into a food gum matrix(XK,consisting of xanthan gum and konjac glucomannan,both FDA-approved food thickening agents)for skin wound healing.In this system,the embedded PDA NPs not only interact with the food gum matrix to form a hydrogel with excellent mechanical strength,but also act as photothermal transduction agents to convert near-infrared laser radiation to heat,thereby triggering bacterial death.Moreover,the XKP hydrogel has high elasticity and tunable water content,enabling it to adapt to the shape of the wound and insulate it,providing a moist environment suitable for healing.In-vivo skin wound healing results clearly demonstrate that XKP can significantly accelerate the healing of wounds by reducing the inflammatory response and promoting vascular reconstruction.In summary,this strategy provides a simple and practical method to overcome the drawbacks of traditional wound dressings,and provides further options when choosing suitable wound healing materials for clinical applications.展开更多
文摘Fractional order calculus can represent systems with high-order dynamics and complex nonlinear phenomena using few coefficients, since the arbitrary order of the derivatives provides an additional degree of freedom to fit a specific behavior. Numerous mathematicians have contributed to the history of fractional calculus by attempting to solve a fundamental problem to the best of their understanding. Each researcher sought a definition and therefore different approaches, which has led to various definitions of differentiation and anti-differentiation of non-integer orders that are proven equivalent. Although all these definitions may be equivalent, from one specific standpoint, i.e., for a specific application, some definitions seem more attractive. Furthermore, it is well known that food gums are complex carbohydrates that can suit for a wide variety of functions in the context of food engineering. The viscoelastic behavior of food gums is crucial for these applications and formulations of new or improved food products. Small progress has been made to understand the viscoelastic behavior of food gums and there are few studies in the literature about these models. In this paper, we applied the Riemann-Liouville approach and the Fourier transform in order to obtain numerical simulations results of a fractional derivative model based on previous literature that to make a quantitative description of the viscoelastic properties behavior for a food gum. The results reveal that the fractional model shows good simulation capability and can be an attractive means for predicting and to elucidate the dynamic viscoelastic behavior of food gums.
基金This work was supported by National Natural Science Foundation of China(31800833 and 21977081)Zhejiang Provincial Natural Science of Foundation of China(LZ19H180001 and LQ19C100001)+3 种基金University of Chinese Academy of Sciences(WIBEZD2017001-03 and WIUCASYJ2020001-2)Wenzhou Medical University(KYYW201901 and KYYW201906)Wenzhou Science and Technology Plan Project(Y20180071)Start-up Scientific Research Foundation of Wenzhou Medical University(KYQD20190513).
文摘Most commonly used wound dressings have severe problems,such as an inability to adapt to wound shape or a lack of antibacterial capacity,affecting their ability to meet the requirements of clinical applications.Here,a nanocomposite hydrogel(XKP)is developed by introducing polydopamine nanoparticles(PDA NPs)into a food gum matrix(XK,consisting of xanthan gum and konjac glucomannan,both FDA-approved food thickening agents)for skin wound healing.In this system,the embedded PDA NPs not only interact with the food gum matrix to form a hydrogel with excellent mechanical strength,but also act as photothermal transduction agents to convert near-infrared laser radiation to heat,thereby triggering bacterial death.Moreover,the XKP hydrogel has high elasticity and tunable water content,enabling it to adapt to the shape of the wound and insulate it,providing a moist environment suitable for healing.In-vivo skin wound healing results clearly demonstrate that XKP can significantly accelerate the healing of wounds by reducing the inflammatory response and promoting vascular reconstruction.In summary,this strategy provides a simple and practical method to overcome the drawbacks of traditional wound dressings,and provides further options when choosing suitable wound healing materials for clinical applications.