Validity of non-local mean filter and novel denoising method

Background Image denoising is an important topic in the digital image processing field.This study theoretically investigates the validity of the classical nonlocal mean filter(NLM)for removing Gaussian noise from a novel statistical perspective.Method By considering the restored image as an estimator of the clear image from a statistical perspective,we gradually analyze the unbiasedness and effectiveness of the restored value obtained by the NLM filter.Subsequently,we propose an improved NLM algorithm called the clustering-based NLM filter that is derived from the conditions obtained through the theoretical analysis.The proposed filter attempts to restore an ideal value using the approximately constant intensities obtained by the image clustering process.In this study,we adopt a mixed probability model on a prefiltered image to generate an estimator of the ideal clustered components.Result The experiment yields improved peak signal-to-noise ratio values and visual results upon the removal of Gaussian noise.Conclusion However,the considerable practical performance of our filter demonstrates that our method is theoretically acceptable as it can effectively estimate ideal images.

Shape correspondence for cel animation based on a shape association graph and spectral matching

We present an effective spectral matching method based on a shape association graph for finding region correspondences between two cel animation keyframes.We formulate the correspondence problem as an adapted quadratic assignment problem,which comprehensively considers both the intrinsic geometric and topology of regions to find the globally optimal correspondence.To simultaneously represent the geometric and topological similarities between regions,we propose a shape association graph(SAG),whose node attributes indicate the geometric distance between regions,and whose edge attributes indicate the topological distance between combined region pairs.We convert topological distance to geometric distance between geometric objects with topological features of the pairs,and introduce Kendall shape space to calculate the intrinsic geometric distance.By utilizing the spectral properties of the affinity matrix induced by the SAG,our approach can efficiently extract globally optimal region correspondences,even if shapes have inconsistent topology and severe deformation.It is also robust to shapes undergoing similarity transformations,and compatible with parallel computing techniques.

Chiral Betaine-Mediated Asymmetric Peroxidation-Kinetic Resolution Cascade for the Synthesis of Optically Pure Peroxides

An array of natural products bearing chiral peroxide motifs display antitumor,anticancer,and antiparasitic activities.However,there are very few catalytic asymmetric syntheses of chiral peroxides.Moreover,effective catalysts for asymmetric catalytic peroxidations are limited to chiral amines.To further expand synthetic access to chiral peroxides,the development of new catalysts realizing catalytic asymmetric peroxidation is highly desirable yet challenging.We report here a catalytic asymmetric peroxidation of anα,β-unsaturated triflone-kinetic resolution cascade reaction,which furnishes chiral peroxides in greater than 99.9%ee.The realization of this cascade reaction resulted from the development of two betaines as novel catalysts for chiral peroxide synthesis;one betaine promoted enantioselective peroxidation ofα,β-unsaturated triflones via conjugate addition affording peroxides in 80-92%ee,while the other betaine catalyzed kinetic resolution of the newly generated chiral peroxides to further increase the ee to greater than 99.9%.

IL-21 regulates macrophage activation in human monocytic THP-1-derived macrophages

Background:Interleukin-21(IL-21)has a regulatory effect on various immune cells.Its effect on macrophage function remains unclear.Aims:This study aimed to investigate the effect of IL-21 on the macrophagesmediated inflammatory response and explore its mechanism.Materials&Methods:Phorbol myristate acetate was used to induce THP-1-derived macrophages.Then,cells were stimulated with IL-21 and/or lipopolysaccharide(LPS).To determine the effect of IL-21 on the production of inflammatory factors in THP-1-derived macrophages,the messenger RNA(mRNA)and protein levels of IL-6,tumor necrosis factor-α(TNF-α),IL-8,and IL-10 were detected by real-time polymerase chain reaction(RT-PCR)and enzyme-linked immunosorbent assay(ELISA),respectively.Meanwhile,to explore the effect of IL-21 on macrophage polarization,macrophage phenotype,gene expression,and cytokine secretion mediated by THP-1-derived macrophage were detected by flow cytometry,RT-PCR,and ELISA.Results:First,we found that the IL-21 receptor was expressed in THP-1-derived macrophages.IL-21 enhanced LPS-mediated TNF-α,IL-6,and IL-10 production in THP-1-derived macrophages.During the polarization of THP-1-derived macrophages to M1-like macrophages,IL-21 induced the expression of macrophage surface markers CD86 and CD80,and related genes,such as TNF-α,IL-6,IL-1β,and DC-SIGN mRNA,inhibited Dectin-1 mRNA expression and promoted the secretion of TNF-α.During the polarization of THP-1-derived macrophages to M2-like macrophages,IL-21 enhanced the expression of macrophage surface markers CD86 and CD163,and related genes,such as TNF-α,IL-1β,IL-10,Dectin-1,and DC-SIGN mRNA,and promoted the secretion of IL-10.Conclusion:IL-21 promotes LPS-mediated production of inflammatory cytokines by THP-1-derived macrophages;IL-21 plays a two-way regulatory role in THP-1-derived macrophage polarization.