Mechanisms, recent advancements and perspectives concerning nonconventional luminophores free of classic conjugates but with intrinsic photoluminescence are discussed.
SUMMARYIn this paper, we present a mathematical framework of the bridging scale method (BSM), recently proposed by Liu et al. Under certain conditions, it had been designed for accurately and efficiently simulating complex dynamics with different spatial scales. From a clear and consistent derivation, we identify two error sources in this method. First, we use a linear finite element interpolation, and derive the coarse grid equations directly from Newton's second law. Numerical error in this length scale exists mainly due to inadequate approximation for the effects of the fine scale fluctuations. An modified linear element (MLE) scheme is developed to improve the accuracy. Secondly, we derive an exact multiscale interfacial condition to treat the interfaces between the molecular dynamics region D and the complementary domain C , using a time history kernel technique. The interfacial condition proposed in the original BSM may be regarded as a leading order approximation to the exact one (with respect to the coarsening ratio). This approximation is responsible for minor reflections across the interfaces, with a dependency on the choice of D . We further illustrate the framework and analysis with linear and non-linear lattices in one-dimensional space.
Thin endometrium is a primary cause of failed embryo transfer, resulting in long‐term infertility and negative family outcomes. While hormonal treatments have greatly improved fertility results for some women, these responses remain unsatisfactory due to damage and infection of the complex endometrial microenvironment. In this study, a multifunctional microenvironment‐protected exosome‐hydrogel is designed for facilitating endometrial regeneration and fertility restoration via in situ microinjection and endometrial regeneration. This exosome hydrogel is formulated via Ag+‐S dynamic coordination and fusion with adipose stem cell‐derived exosomes (ADSC‐exo), yielding an injectable preparation that is sufficient to mitigate infection risk while also possessing the antigenic contents and paracrine signaling activity of the ADSC source cells, enabling regeneration of the endometrial microenvironment. In vitro, this exosome‐hydrogel exerts an outstanding neovascularization‐promoting effect, increased human umbilical vein endothelial cell proliferation and tube formation for 1.87 and 2.2 folds. In vivo, microenvironment‐protected exosome‐hydrogel also reveals to promote neovascularization and tissue regeneration while suppressing local tissue fibrosis. Importantly, regenerated endometrial tissue is more receptive to give embryos and birth to a healthy newborn. This microenvironment‐protected exosome‐hydrogel system offers a convenient, safe, and noninvasive approach for repairing thin endometrium and fertility restoration.
In this paper, we propose an immersed solid system (ISS) method to efficiently treat the fluid-structure interaction (FSI) problems. Augmenting a fluid in the moving solid domain, we introduce a volumetric force to obtain the correct dynamics for both the fluid and the structure. We further define an Euler-Lagrange mapping to describe the motion of the immersed solid. A weak formulation (WF) is then constructed and shown to be equivalent to both the FSI and the ISS under certain regularity assumptions. The weak formulation (WF) may be computed numerically by an implicit algorithm with the finite element method, and the streamline upwind/Petrov-Galerkin method. Compared with the successful immersed boundary method (IBM) by Peskin and co-workers (J Comput
In this paper, we propose a pseudo-spectral multiscale method for simulating complex systems with more than one spatial scale. Using a spectral decomposition, we split the displacement into its mean and fluctuation parts. Under the assumption of localized nonlinear fluctuations, we separate the domain into an MD (Molecular Dynamics) subdomain and an MC (MacrosCopic) subdomain. An interfacial condition is proposed across the two scales, in terms of a time history treatment. In the special case of a linear system, this is the first exact interfacial condition for multiscale computations. Meanwhile, we design coarse grid equations using a matching differential operator approach. The coarse grid discretization is of spectral accuracy. We do not use a handshaking region in this method. Instead, we define a coarse grid over the whole domain and reassign the coarse grid displacement in the MD subdomain with an average of the MD solution. To reduce the computational cost, we compute the dynamics of the coarse grid displacement and relate it to the mean displacement. Our method is therefore called a pseudo-spectral multiscale method. It allows one to reach high resolution by balancing the accuracy at the coarse grid with that at the interface. Numerical experiments in one-and two-space dimensions are presented to demonstrate the accuracy and the robustness of the method.
Fisher's equation, which describes a balance between linear diffusion and nonlinear reaction or multiplication, is studied numerically by a Petrov-Galerkin finite element method. The results show that any local initial disturbance can propagate with a constant limiting speed when time becomes sufficiently large. Both the limiting wave fronts and the limiting speed are determined by the system itself and are independent of the initial values. Comparing with other studies, the numerical scheme used in this paper is satisfactory with regard to its accuracy and stability. It has the advantage of being much more concise.
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