Search

In this article, we will investigate the local ultraconvergence of the displacement and derivative of finite element solution using piecewise polynomials of degrees k (k ≥ 2) by Richardson extrapolation operators P1k and P2k presented in He et al. for second‐order elliptic problems with singularity. Numerical results are provided to illustrate the theoretic findings. [ABSTRACT FROM AUTHOR]

An efficient Legendre–Galerkin spectral element method for the steady flows in rectangular cavities is proposed in this paper. Firstly, we eliminate the singularity of biharmonic equation in rectangular cavity at the corner by the singularity substraction technique. Then we construct some appropriate interior basis functions and interface basis functions which maintain C 1 -continuity. Consequently, the discrete variational formulation is reduced to a linear system with block diagonal and well-conditioned coefficient matrix, which can be efficiently solved by the conjugate gradient iteration method. Finally, several numerical examples are given to show the effectiveness of our numerical method. The present method is used to solve the creeping flows in rectangular cavities, the numerical results are compared well with the benchmark steady solutions provided by the finite difference method. [ABSTRACT FROM AUTHOR]

Exogenous supplementation of antioxidants with ROS scavenging activity would be a potential therapy to cerebral ischemia-reperfusion injury in stroke. In the present study, a series of NDGA analogues with attenuation oxidative stress by directly scavenging ROS and indirectly through keap1/Nrf2/ARE pathway activation were designed and synthesized. All analogues were found to effectively remove ROS directly by DPPH radical scavenging assay, and compound 3a conferred potent protection from the oxidative injury in PC12 cells via promoting Nrf2 to translocate into nucleus and increasing expression of heme oxygenase-1(HO-1), where strongly reduced intracellular ROS level indirectly. More importantly, 3a significantly reduced brain infarction after cerebral ischemia-reperfusion injury in rats subjected to transient middle cerebral artery occlusion (MCAO). Overall, our findings shown compound 3a could serve as a promising compound for the treatment of stroke. [ABSTRACT FROM AUTHOR]

Backgroup: Bis-chalcone compounds with symmetrical structures, either isolated from natural products or chemically synthesized, have multiple pharmacological activities. Asymmetric Bis-chalcone compounds have not been reported before, which might be attributed to the synthetic challenges involved, and it remains unknown whether these compounds possess any potential pharmacological activities., Aims: The aim of this study is to investigate the synthesis route of asymmetric bis-chalcone compounds and identify potential candidates with efficient anti-tumor activity., Method: The two-step structural optimization of the bis-chalcone compounds was carried out sequentially, guided by the screening of the compounds for their growth inhibitory activity against gastric cancer cells by MTT assay. The QSAR model of compounds was established through random forest (RF) algorithm. The activities of the optimal compound J3 on growth inhibition, apoptosis, and apoptosis-inducing protein expression in gastric cancer cells were investigated sequentially by colony formation assay, flow cytometry, and western blotting. Further, the inhibitory effects of J3 on the FGFR1 signaling pathway were explored by Wester Blotting, siRNA, and MTT assays. Finally, the in vivo anti-tumor activity and mechanism of J3 were studied through nude mouse xenograft assay, western blotting., Result: 27 asymmetric bis-chalcone compounds, including two types (N and J) were sequentially designed and synthesized. Some N-class compounds have good inhibitory activity on the growth of gastric cancer cells. The vast majority of J-class compounds optimized on the basis of N3 exhibit excellent inhibitory activity on gastric cancer cell growth. We established a QSAR model (R2 = 0.851627) by applying random forest algorithms. The optimal compound J3, which has better activity, concentration-dependently inhibited the formation of gastric cancer cell colonies and led to cell apoptosis by inducing the expression of the pro-apoptotic protein cleaved PARP. J3 may exert anti-gastric cancer effects by inhibiting the activation of FGFR1/ERK pathway. Moreover, at a dose of 10 mg/kg/day, J3 inhibited tumor growth in nude mice by nearly 70% in vivo with no significant toxic effect on body weight and organs., Conclusion: In summary, this study outlines a viable method for the synthesis of novel asymmetric bischalcone compounds. Furthermore, the compound J3 demonstrates substantial promise as a potential candidate for an anti-tumor drug., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Retinal tears (RTs) are usually detected by B-scan ultrasound images, particularly for individuals with complex eye conditions. However, traditional manual techniques for reading ultrasound images have the potential to overlook or inaccurately diagnose conditions. Thus, the development of rapid and accurate approaches for the diagnosis of an RT is highly important and urgent. The present study introduces a novel hybrid deep-learning model called DCT-Net to enable the automatic and precise diagnosis of RTs. The implemented model utilizes a vision transformer as the backbone and feature extractor. Additionally, in order to accommodate the edge characteristics of the lesion areas, a novel module called the residual deformable convolution has been incorporated. Furthermore, normalization is employed to mitigate the issue of overfitting and, a Softmax layer has been included to achieve the final classification following the acquisition of the global and local representations. The study was conducted by using both our proprietary dataset and a publicly available dataset. In addition, interpretability of the trained model was assessed by generating attention maps using the attention rollout approach. On the private dataset, the model demonstrated a high level of performance, with an accuracy of 97.78%, precision of 97.34%, recall rate of 97.13%, and an F1 score of 0.9682. On the other hand, the model developed by using the public funds image dataset demonstrated an accuracy of 83.82%, a sensitivity of 82.69% and a specificity of 82.40%. The findings, therefore present a novel framework for the diagnosis of RTs that is characterized by a high degree of efficiency, accuracy and interpretability. Accordingly, the technology exhibits considerable promise and has the potential to serve as a reliable tool for ophthalmologists.

Background: The transcription factor nuclear factor-κB (NF-κB) is constitutively activated in a variety of human cancers, including gastric cancer. NF-κB inhibitors that selectively kill cancer cells are urgently needed for cancer treatment. Curcumin is a potent inhibitor of NF-κB activation. Unfortunately, the therapeutic potential of curcumin is limited by its relatively low potency and poor cellular bioavailability. In this study, we presented a novel NF-κB inhibitor named Da0324, a synthetic asymmetric mono-carbonyl analog of curcumin. The purpose of this study is to research the expression of NF-κB in gastric cancer and the antitumor activity and mechanism of Da0324 on human gastric cancer cells., Methods: The expressions between gastric cancer tissues/cells and normal gastric tissues/cells of NF-κB were evaluated by Western blot. The inhibition viability of compounds on human gastric cancer cell lines SGC-7901, BGC-823, MGC-803, and normal gastric mucosa epithelial cell line GES-1 was assessed with the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Absorption spectrum method and high-performance liquid chromatography method detected the stability of the compound in vitro. The compound-induced changes of inducible NF-κB activation in the SGC-7901 and BGC-823 cells were examined by Western blot analysis and immunofluorescence methods. The antitumor activity of compound was performed by clonogenic assay, matrigel invasion assay, flow cytometric analysis, Western blot analysis, and Hoechst 33258 staining assay., Results: High levels of p65 were found in gastric cancer tissues and cells. Da0324 displayed higher growth inhibition against several types of gastric cancer cell lines and showed relatively low toxicity to GES-1. Moreover, Da0324 was more stable than curcumin in vitro. Western blot analysis and immunofluorescence methods showed that Da0324 blocked NF-κB activation. In addition, Da0324 significantly inhibited tumor proliferation and invasion, arrested the cell cycle, and induced apoptosis in vitro., Conclusion: The asymmetric mono-carbonyl analog of curcumin Da0324 exhibited significantly improved antigastric cancer activity. Da0324 may be a promising NF-κB inhibitor for the selective targeting of cancer cells. However, further studies are needed in animals to validate these findings for the therapeutic use of Da0324.