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In this paper, a fast finite volume method is proposed for the initial and boundary value problems of spatial fractional diffusion equations on nonuniform meshes. The discretizations of the Riemann-Liouville fractional derivatives lead to unstructured dense coefficient matrices, differing from the Toeplitz-like structure under the uniform mesh. The fast algorithm is proposed by using the sum-of-exponentials (SOE) technique to the spatial kernel x α − 1 , α ∈ (0 , 1). Then, the matrix-vector multiplications of the resulting coefficient matrices could be implemented in O (m log 2 ⁡ m) operations, where m denotes the size of matrices. Iterative solvers are preferably applied to obtain the numerical solution. The proposed fast scheme is proved to be unconditionally stable for sufficiently accurate SOE approximation. Meanwhile, a banded preconditioner is exploited to accelerate the Krylov subspace method. Numerical experiments are provided to demonstrate the efficiency of the proposed fast algorithm. [ABSTRACT FROM AUTHOR]

Diabetic vascular calcification in the arterial intima is closely associated with endothelial-to-mesenchymal transition (EndMT). Glucose metabolism reprogramming is involved in EndMT. Although brain-derived neurotrophic factor (BDNF) and Krüppel-like family of transcription factor 2 (KLF2) play protective roles in the physiological activity of the vascular endothelium, the underlying mechanisms are unclear. Human umbilical vein endothelial cells (HUVECs) were incubated with diabetic osteogenic medium (DOM) to induce EndMT and accelerate osteogenic differentiation. Glycolysis in HUVECs was assessed by monitoring glucose uptake, lactate production, extracellular acidification rate and expression of key glycolytic enzymes. DOM induced EndMT and accelerated osteo-induction in HUVECs, which was alleviated by BDNF/tropomyosin receptor kinase B (TrkB) pathway. Mechanistically, DOM caused hyperactivation of glycolysis in HUVECs and inhibition of the BDNF/TrkB pathway. BDNF preserved KLF2 and downregulated hexokinase 1 (HK1) in HUVECs after DOM treatment. Furthermore, KLF2 interacted with HK1. Increased KLF2 alleviated HK1-mediated glucose metabolism abnormality. HK1 knockdown or a targeted glycolysis inhibitor suppressed EndMT, apoptosis, inflammation and vascular calcification of HUVECs after DOM exposure. This study suggests that KLF2 mediates the suppressive effect of BDNF on diabetic intimal calcification by inhibiting HK1-induced glucose metabolism reprogramming and the EndMT process. • BDNF inhibited the EndMT process and alleviated diabetic osteo-induction in HUVECs. • DOM induced glycolysis hyperactivation, which was partly suppressed via the BDNF/TrkB/KLF2 pathway. • HK1 knockdown or glycolysis blockade diminished DOM-induced EndMT and HUVECs calcification. [ABSTRACT FROM AUTHOR]

Background: Our early studies performed on aged rats, ovariectomized (OVX) rats and diabetic mice, indicated the calciotropic role of Fructus Ligustri Lucidi (FLL), the fruit of Ligustrum lucidum Ait., in mediating calcium homeostasis which was partially attributed to its stimulation on renal calcium reabsorption.Purpose: This study aimed to explicate the underlying molecular mechanism and explore the potential bioactive ingredients in FLL.Study Design and Methods: The OVX C57BL/6 J mice were orally administered with low (FL, 75 mg/kg), middle (FM, 225 mg/kg) or high (FH, 675 mg/kg) dose of extract of Fructus Ligustri Lucidi for 10 weeks. The biological properties of trabecular bone were measured by micro-CT and H&E staining. The molecular expression was assessed by immunoblotting and immunostaining. The potential active components were identified by cell membrane chromatography (CMC) and explored in renal tubular cells with Fluo-3/AM fluorescent staining to indicate intracellular calcium level. The male mice fed with high calcium diet (1.2% Ca) and orally treated with active components for 3 weeks.Results: Treatment of OVX mice with FLL extract suppressed the elevation in urinary calcium level (FH, 0.081 ± 0.012, vs. OVX, 0.189 ± 0.038 mg/mg), and increased bone mineral density (FH, 62.41 ± 2.57, vs. OVX, 43.72 ± 8.43 mg/ccm) and percentage of trabecular bone area. It also decreased circulating PTH level (FH, 66.69 ± 10.94, vs. OVX, 303.50 ± 26.56 pg/ml) and up-regulated TRPV5 expression in renal cortex of OVX mice as well as enhanced the expression of PTH receptor (PTH1R) and the ratio of p-PKA/PKA. The PKA inhibitor H89 abolished the induction of serum, prepared from rats treated with FLL extract, on PKA/TRPV5 signaling in renal tubular cells. The CMC identified phenol glycosides, including salidroside and oleuropein, which increased intracellular calcium content, promoted expression of PTH1R and TRPV5 and ratio of p-PKA/PKA as well as decreased calcium excretion in urine of mice fed with high calcium diet.Conclusion: Salidroside and oleuropein are major ingredients contributing to the anti-hypercalciuria effects of FLL via acting on PTH1R/PKA/TRPV5 signaling in kidney. Further translational research would be required. [ABSTRACT FROM AUTHOR]

Background: Coronavirus disease-2019 (COVID-19) caused by infection with severe acute respiratory coronavirus-2 (SARS-CoV-2) has been spreading rapidly throughout China and in other countries since the end of 2019. The World Health Organization (WHO) has declared that the epidemic is a public health emergency of international concerns. The timely and appropriate measures for treating COVID-19 in China, which are inseparable from the contribution of traditional Chinese medicine (TCM), have won much praise of the world.Purpose: This review aimed to summarize and discuss the essential role of TCM in protecting tissues from injuries associated with COVID-19, and accordingly to clarify the possible action mechanisms of TCM from the perspectives of anti-inflammatory, antioxidant and anti-apoptotic effects.Methods: Electronic databases such as Pubmed, ResearchGate, Science Direct, Web of Science, medRixv and Wiley were used to search scientific literatures.Results: The present review found that traditional Chinese herbs commonly used for the clinical treatment of organ damages caused by COVID-19, such as Scutellaria baicalensis, Salvia miltiorrhizaSalvia miltiorrhiza, and ginseng, could act on multiple signaling pathways involved in inflammation, oxidative stress and apoptosis.Conclusion: TCM could protect COVID-19 patients from tissue injuries, a protection that might be, at least partially, attributed to the anti-inflammatory, antioxidant and anti-apoptotic effects of the TCM under investigation. This review provides evidence and support for clinical treatment and novel drug research using TCM. [ABSTRACT FROM AUTHOR]

A finite difference scheme is developed for solving the phase field crystal equation with the Dirichlet boundary condition. The second-order stabilized semi-implicit scheme is applied to discretize the time variable. The mass conservation, unique solvability of the semi-discrete scheme are proved. Then, the spatial discretization is attained by the fourth-order compact difference scheme. The unconditional energy stability and convergence analysis of the fully-discrete scheme are presented. In the implementation, a fast sine transform technique is utilized to reduce the computational cost. Several numerical examples are presented to verify the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

Nuclear factor-kappa B (NF-κB) and autophagy are two major regulators involved in both tumor initiation and progression. However, the association between these two signaling pathways still remains obscure. In this work, we demonstrate that dihydroartemisinin (DHA) stimulates the induction of autophagy in several cancer cell lines through repression of NF-κB activity. We also show that inhibiting NF-κB results in an accumulation of reactive oxygen species (ROS), which participate in the stimulation of autophagy. These findings present a pathway by which DHA promotes autophagy in cancer cells and provide evidence for the DHA-induced sensitization effect of some chemotherapeutics. [ABSTRACT FROM AUTHOR]

Abstract: The effect of a commercial lipase on chitosan degradation was investigated. When four chitosans with various degrees of deacetylation were used as substrates, the lipase showed higher optimal pH toward chitosan with higher DD (degree of deacetylation). The optimal temperature of the lipase was 55°C for all chitosans. The enzyme exhibited higher activity to chitosans which were 82.8% and 73.2% deacetylated. Kinetics experiments show that chitosans with DD of 82.8% and 73.2% which resulted in lower K m values had stronger affinity for the lipase. The chitosan hydrolysis carried out at 37°C produced larger quantity of COS (chitooligosaccharides) than that at 55°C when the reaction time was longer than 6h, and COS yield of 24h hydrolysis at 37°C was 93.8%. Products analysis results demonstrate that the enzyme produced glucosamine and chitooligosaccharides with DP (degree of polymerization) of 2–6 and above, and it acted on chitosan in both exo- and endo-hydrolytic manner. [Copyright &y& Elsevier]

A copper-catalyzed decarboxylative/dehydrogenative cross-coupling reaction of α-fluoroacrylic acids with silanes has been developed. A wide range of α-fluoroacrylic acids containing many critical functional groups reacted smoothly, giving desired monofluoroalkenyl silanes with excellent E -stereoselectivity. This protocol provides a convenient strategy for accessing monofluoroalkenyl silanes, without using expensive iridium catalysts to prepare the silylborane and without the need for harsh conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

• Two-dimensional distributed-order time-space fractional diffusion problem is considered and its finite difference discretization is studied. • The stability and convergence of the scheme are investigated. • The spatial second-order convergence and the temporal optimal convergence are obtained. • A fast and memory saving algorithm for solving DO time-space fractional diffusion equation is developed through Gauss quadrature formula, ESA method and PCG method. • Numerical experiments show strong effectiveness and efficiency of the method. In this paper, a fast algorithm is proposed for solving distributed-order time-space fractional diffusion equations. Integral terms in time and space directions are discretized by the Gauss-Legendre quadrature formula. The Caputo fractional derivatives are approximated by the exponential-sum-approximation method, and the finite difference method is applied for spatial approximation. The coefficient matrix of the discretized linear system is symmetric positive definite and possesses block-Toeplitz-Toeplitz-block structure. The preconditioned conjugate gradient method with a block-circulant-circulant-block preconditioner is employed to solve the linear system. Theoretically, the stability and convergence of the proposed scheme are discussed. Numerical experiments are carried out to demonstrate the effectiveness of the scheme. [ABSTRACT FROM AUTHOR]

• Protein modification significantly decreased the allergenic reactivity of α-Lactalbumin. • The type, number and location of the modified sites affected allergenic reactivity. • Shielding effect and conformational changes reduced allergenic reactivity of α-Lactalbumin. Bovine α-lactalbumin (α-Lac) allergy is a common health problem. This study assesses the allergenic reactivity and the structural properties of α-Lac after protein modification (glycation, phosphorylation and acetylation) by ELISA, cells experiment and high-resolution mass spectrometry. Three modified methods significantly reduced the IgE/IgG-binding capacity, and the release of histamine and interleukin-6, and changed the conformational structure of α-Lac. α-Lac was glycated at K13, K16, K94, K98, and K108, phosphorylated at Y18, S22, Y103, and S112, and acetylated at K13, T33, S34, T38, S47, K62, S69, S70, K108, and K114, respectively, leading to masking the linear epitopes of α-Lac. Therefore, the decrease of allergenic reactivity of α-Lac induced by glycation, phosphorylation and acetylation depends upon not only the shielding effect of their modified sites, but also the change of conformational structure. This study confirmed that protein modification was a promising method for decreasing the allergenic reactivity of allergic proteins. [ABSTRACT FROM AUTHOR]