Accurate image segmentation results would show a great significance to computer vision-based manufacturing for complex helical surface. However, the image segmentation for complex helical surface is always a difficult problem because of the uneven gray distribution and non-homogeneous feature patterns of its images. Therefore, a multi-direction evolutionary segmentation model is constructed and a multi-population cooperative evolution algorithm is proposed to solve the new model. According to the characteristics of gray distribution and feature patterns of complex helical surface image, an eigenvector extraction and description strategy is researched by combining gray level co-occurrence matrix algorithm with fractal algorithm, and the complex helical surface image can be described succinctly by gray feature and shape feature. Based on the description algorithm of image features, an image segmentation strategy using cooperative evolution from different eigenvector is discussed, and the helical surface image segmentation is decomposed from a single objective optimization problem to a multi-objective optimization problem to improve the accuracy of segmentation. Meanwhile, a multi-objective particle swarm optimization algorithm based on multi-directional evolution and shared archives is presented. Due to the fact that each eigenvector segmentation corresponds to one evolution direction, the collaboration of local and global segmentation can be realized by information sharing and interaction between evolution directions and the archive set. The comprehensive quality of non-dominated solution can be improved by the selection strategy of local and global optimal solution as well as the archive set maintenance. The practical numerical experiments for complex helical surface image segmentation are carried out to prove the validity of the proposed model and algorithm.
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http://dx.doi.org/10.3934/mbe.2020385 | DOI Listing |
Nat Commun
December 2024
Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, India.
Secondary nucleation is an emerging approach for synthesizing higher-order supramolecular polymers with exciting topologies. However, a detailed understanding of growth processes and the synthesis of homochiral superstructures is yet to be demonstrated. Here, we report the non-covalent synthesis of dendritic homochiral superstructures using NIR triimide dyes as building blocks via a secondary nucleation elongation process.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
Optical vortices possess a helical phase wavefront with central phase dislocation and orbital angular momentum. We demonstrated three-dimensional microstructure formation using a femtosecond optical vortex beam. Two-photon polymerization of photocurable resin was induced by long-term exposure, resulting in the fabrication of cylindrical structures.
View Article and Find Full Text PDFRadiother Oncol
December 2024
Medical Physics Unit, IRCCS, Istituto Romagnolo per lo Studio dei Tumori (IRST) "Dino Amadori", Italy. Electronic address:
Purpose: This study aims to investigate and compare High Dose Rate Brachytherapy (HDR-BT) with Helical Tomotherapy (HT) treatment plans. The focus is on small target volumes near radiation-sensitive organs in the ocular region, to evaluate the advantages of these techniques in treating skin cancer.
Methods: This retrospective observational analysis included patients who underwent skin cancer HDR-BT Freiburg flap treatment between 2019 and 2023.
Angew Chem Int Ed Engl
December 2024
Université de Bordeaux, CBMN UMR5248, IECB, 2, rue Robert Escarpit, 33607, PESSAC, FRANCE.
Peptide stapling has emerged as a versatile approach in drug discovery to reinforce secondary structure elements especially α-helices and improve properties of linear bioactive peptides. Inspired by the prevalence of arginine in protein-protein and protein-DNA interfaces, we investigated guanidinium-stapling as a means to constrain helical peptides. Guanidinium stapling was readily achieved on solid support, utilizing two orthogonally protected lysine or unatural α-amino acid residues with an amino function.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Ludwig-Maximilians-Universitat Munchen, Pharmacy, Butenandtstraße 5 - 13, 81377, Munich, GERMANY.
Helical aromatic oligoamide foldamers bearing anionic side chains that mimic the overall shape and charge surface distribution of DNA were synthesized. Their interactions with chromosomal protein Sac7d, a non-sequence-selective DNA-binder that kinks DNA, were investigated by Surface Plasmon Resonance (SPR), Isothermal Titration Calorimetry (ITC), Circular Dichroism spectroscopy (CD), melting curve analysis, Atomic Force Microscopy (AFM), and Nuclear Magnetic Resonance (NMR), as well as by single crystal X-ray crystallography. The foldamers were shown to bind to Sac7d better than a DNA duplex of comparable length.
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