37,067 results match your criteria three-dimensional structures

Arterial Vascular Structures running through Retrotransverse Foramen and Retrotransverse Groove of the Atlas Vertebrae.

World Neurosurg 2021 Jul 19. Epub 2021 Jul 19.

Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, China. Electronic address:

Objective: Retrotransverse foramen (RTF) and Retrotransverse groove (RTG) are anatomic variations of the atlas (C1) vertebrae , RTF contained an anastomotic vein connecting atlanto-occipital and atlanto-axodian venous sinuses. The purpose of this study is to analyze the arterial vascular structures running though the RTF and RTG.

Methods: Three-dimensional Volume Rendered Computed Tomography Angiography (3D VR CTA) images of 427 subjects (264 males, 163 females, aged between 17 and 87 years) were reviewed and evaluated by using Radiant DICOM Viewer. Read More

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Conformation-modulated three-dimensional electrocatalysts for high-performance fuel cell electrodes.

Sci Adv 2021 Jul 21;7(30). Epub 2021 Jul 21.

Center for Hydrogen and Fuel Cell Research, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea.

Unsupported Pt electrocatalysts demonstrate excellent electrochemical stability when used in polymer electrolyte membrane fuel cells; however, their extreme thinness and low porosity result in insufficient surface area and high mass transfer resistance. Here, we introduce three-dimensionally (3D) customized, multiscale Pt nanoarchitectures (PtNAs) composed of dense and narrow (for sufficient active sites) and sparse (for improved mass transfer) nanoscale building blocks. The 3D-multiscale PtNA fabricated by ultrahigh-resolution nanotransfer printing exhibited excellent performance (45% enhanced maximum power density) and high durability (only 5% loss of surface area for 5000 cycles) compared to commercial Pt/C. Read More

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[Establishment of mini-guts organoid and research on intestinal disease from the new perspective].

Zhonghua Wei Chang Wai Ke Za Zhi 2021 Jul;24(7):638-643

Research Institute of General Surgery, Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China.

Intestinal organoids, also named "mini-guts", reconstitute sophisticated three-dimensional architecture recapitulating diversified intestinal epithelial cell types and physiology, which is driven by the proliferative and self-assembling characteristics of crypt stem cells. The initiation of organoids study relies on the identification of Lgr5+ crypt stem cells from different intestinal segments and the key role of EGF, Wnt, BMP/TGF-β, Notch signal pathways within the microenvironment during the cultivation process. Besides constituting polarized crypt-villus structures, these "mini-guts" exhibit various effective functions of intestinal epithelium. Read More

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Linear and Nonlinear Optical Properties of Centrosymmetric SbOSO and Noncentrosymmetric SbO(SO)(OH) Induced by Lone Pair Stereoactivity.

Inorg Chem 2021 Jul 21. Epub 2021 Jul 21.

College of Chemistry and Chemical Engineering, Qingdao University, Qingdao, Shandong 266071, P. R. China.

Introducing stereochemically active lone-pair Sb cations into sulfates, two three-dimensional (3D) antimony-sulfates, SbOSO () and SbO(SO)(OH) (), were achieved under moderate hydrothermal conditions. Both structures are constructed by tetranuclear-{Sb}-clusters-based layers and SO tetrahedra. However, owing to the different packing patterns of the layers, they display different characteristics: exhibits a centrosymmetric structure while possesses a noncentrosymmetric structure. Read More

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Deciphering CAD: Structure and function of a mega-enzymatic pyrimidine factory in health and disease.

Protein Sci 2021 Jul 19. Epub 2021 Jul 19.

Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain.

CAD is a 1.5 MDa particle formed by hexameric association of a 250 kDa protein divided into different enzymatic domains, each catalyzing one of the initial reactions for de novo biosynthesis of pyrimidine nucleotides: glutaminase-dependent Carbamoyl phosphate synthetase, Aspartate transcarbamoylase, and Dihydroorotase. The pathway for de novo pyrimidine synthesis is essential for cell proliferation and is conserved in all living organisms, but the covalent linkage of the first enzymatic activities into a multienzymatic CAD particle is unique to animals. Read More

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Progress and Perspectives on Covalent Organic Frameworks (COFs) and Composites for Various Energy Applications.

Chemistry 2021 Jul 19. Epub 2021 Jul 19.

Indian Institute of Technology Indore, Deptm. of Chemistry, Khandwa Road, Simrol, 452020, Indore, INDIA.

Covalent organic frameworks (COFs), being a new member of crystalline porous materials' family, have emerged as important materials for energy storage/conversion/generation devices. They possess high surface areas, ordered micro/mesopores, designable structures and an ability to precisely control electro-active groups in their pores, which broaden their application window. Thanks to their low weight density, long range crystallinity, reticular nature and tunable synthesis approach towards two and three dimensional (2D and 3D) networks, they have been found suitable for a range of challenging electrochemical applications. Read More

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Extrusion-Based 3D Printing for Highly Porous Alginate Materials Production.

Gels 2021 Jul 14;7(3). Epub 2021 Jul 14.

International Science and Educational Center for Transfer of Pharmaceutical and Biotechnologies, Mendeleev University of Chemical Technology of Russia, Miusskaya pl. 9, 125047 Moscow, Russia.

Three-dimensional (3D) printing is a promising technology for solving a wide range of problems: regenerative medicine, tissue engineering, chemistry, etc. One of the potential applications of additive technologies is the production of highly porous structures with complex geometries, while printing is carried out using gel-like materials. However, the implementation of precise gel printing is a difficult task due to the high requirements for "ink". Read More

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Dendritic nanoparticle self-assembly from drying a sessile nanofluid droplet.

Phys Chem Chem Phys 2021 Jul 20. Epub 2021 Jul 20.

School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.

The pattern formation left by a drying nanofluid droplet is related to the evaporation induced particle self-assembly. The experimental results demonstrate the formation of dendritic particle deposition after the liquid phase of unpinned sessile nanofluid droplets is fully evaporated. The dried-in particle assemblies exhibit the dendritic patterns connecting the sprawling branches with a central core structure. Read More

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Coaxial Electrohydrodynamic Bioprinting of Pre-vascularized Cell-laden Constructs for Tissue Engineering.

Int J Bioprint 2021 4;7(3):362. Epub 2021 Jun 4.

State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China.

Recapitulating the vascular networks that maintain the delivery of nutrition, oxygen, and byproducts for the living cells within the three-dimensional (3D) tissue constructs is a challenging issue in the tissue-engineering area. Here, a novel coaxial electrohydrodynamic (EHD) bioprinting strategy is presented to fabricate thick pre-vascularized cell-laden constructs. The alginate and collagen/calcium chloride solution were utilized as the outer-layer and inner-layer bioink, respectively, in the coaxial printing nozzle to produce the core-sheath hydrogel filaments. Read More

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3D Printing of Layered Gradient Pore Structure of Brain-like Tissue.

Int J Bioprint 2021 15;7(3):359. Epub 2021 Jun 15.

State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, 710054, Xi'an, Shaanxi, China.

The pathological research and drug development of brain diseases require appropriate brain models. Given the complex, layered structure of the cerebral cortex, as well as the constraints on the medical ethics and the inaccuracy of animal models, it is necessary to construct a brain-like model . In this study, we designed and built integrated three-dimensional (3D) printing equipment for cell printing/culture, which can guarantee cell viability in the printing process and provide the equipment foundation for manufacturing the layered structures with gradient distribution of pore size. Read More

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Three-dimensional non-destructive visualization of teeth enamel microcracks using X-ray micro-computed tomography.

Sci Rep 2021 Jul 20;11(1):14810. Epub 2021 Jul 20.

Laser Research Center, Faculty of Physics, Vilnius University, Vilnius, Lithuania.

Although the topic of tooth fractures has been extensively analyzed in the dental literature, there is still insufficient information about the potential effect of enamel microcracks (EMCs) on the underlying tooth structures. For a precise examination of the extent of the damage to the tooth structure in the area of EMCs, it is necessary to carry out their volumetric [(three-dimensional (3D)] evaluation. The aim of this study was to validate an X-ray micro-computed tomography ([Formula: see text]CT) as a technique suitable for 3D non-destructive visualization and qualitative analysis of teeth EMCs of different severity. Read More

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Self-assembly of Rylene-decorated Guanine Ribbons on Graphene Surface for Optoelectronic Applications: A Theoretical Study.

Nanotechnology 2021 Jul 20. Epub 2021 Jul 20.

, University of Belgrade Institute for Multidisciplinary Research, Kneza Višeslava 1, Belgrade, 11000, SERBIA.

We are witnessing a change of paradigm from the conventional top-down to the bottom-up fabrication of nanodevices and particularly optoelectronic devices. A promising example of the bottom-up approach is self-assembling of molecules into layers with predictable and reproducible structural, electronic and optical properties. Nucleobases possess extraordinary ability to self-assembly into one-, two-, and three-dimensional structures. Read More

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A virtual-reality imaging analysis of the dynamic aortic root anatomy.

Ann Thorac Surg 2021 Jul 17. Epub 2021 Jul 17.

Department of Cardiovascular Surgery, Shiga University of Medical Science, Setatsukinowa-cho, Otsu, Shiga 520-2192, Japan.

Purpose: To measure and explore complex cardiac anatomy in research and preoperative simulation, a virtual imaging technology, the Vesalius 3D suite, combines Vesalius 3D three-dimensional (3D) image-processing software with an optic-tracking navigation system running PST-Client software. We present a novel method of evaluating dynamic aortic root geometry in vivo using this visualization system.

Description: Based on electrocardiography-gated cardiac computed tomography data in systole and diastole, images of the aortic root in a normal healthy adult were reconstructed for 3D visualization. Read More

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Revealing the Phase Separation Behavior of Thermodynamically Immiscible Elements in a Nanoparticle.

Nano Lett 2021 Jul 20. Epub 2021 Jul 20.

Kavli Energy Nanoscience Institute, University of California, Berkeley, California 94720, United States.

Phase-separation is commonly observed in multimetallic nanomaterials, yet it is not well understood how immiscible elements distribute in a thermodynamically stable nanoparticle. Herein, we studied the phase-separation of Au and Rh in nanoparticles using electron microscopy and tomography techniques. The nanoparticles were thermally annealed to form thermodynamically stable structures. Read More

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In Situ Optical Characterization of Twinning in Liquid Crystalline Blue Phases.

ACS Appl Mater Interfaces 2021 Jul 20. Epub 2021 Jul 20.

Division of Electrical, Electronic and Infocommunications Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.

Crystal twinning is an intergrowth of two or more single crystals of the same species with specific crystallographic relations in their orientations. Here, we perform microscopic optical characterization of (211) twins in the three-dimensional liquid crystalline phase known as the blue phase (BP), with I432 space group symmetry. We describe the effect of twinning on the optical diffraction pattern-Kossel pattern-of blue phases and analyze the patterns to deduce structural information such as the twin elements and the previously unnoticed deviations from the perfect cubic structure at zero electric field. Read More

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Airway Management of the Deformed Trachea Using T-Tube Stents in Patients with Mucopolysaccharidosis Type IVA.

Ann Otol Rhinol Laryngol 2021 Jul 20:34894211032778. Epub 2021 Jul 20.

Department of Otorhinolaryngology-Head and Neck Surgery, MacKay Memorial Hospital, Taipei.

Introduction: Mucopolysaccharidosis (MPS) type IVA usually results in airway obstruction due to thoracic cage deformity and crowding of intrathoracic structures, causing tracheal compression by the tortuous innominate artery.

Objectives: To offer an alternative and effective method in dealing with the challenged deformity of the airway in patients with MPS type IVA.

Methods: We present 3 patients with MPS type IVA who underwent airway stenting using Montgomery T-tube stents. Read More

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Chained Structure of Dimeric F-like ATPase in Mycoplasma mobile Gliding Machinery.

mBio 2021 Jul 20:e0141421. Epub 2021 Jul 20.

Graduate School of Science, Osaka City Universitygrid.261445.0, Osaka, Osaka, Japan.

Mycoplasma mobile, a fish pathogen, exhibits gliding motility using ATP hydrolysis on solid surfaces, including animal cells. The gliding machinery can be divided into surface and internal structures. The internal structure of the motor is composed of 28 so-called "chains" that are each composed of 17 repeating protein units called "particles. Read More

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Single Copy Oligonucleotide Fluorescence In Situ Hybridization Probe Design Platforms: Development, Application and Evaluation.

Int J Mol Sci 2021 Jul 1;22(13). Epub 2021 Jul 1.

Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Agricultural College of Yangzhou University, Yangzhou 225009, China.

Oligonucleotides fluorescence in situ hybridization (Oligo-FISH) is an emerging technology and is an important tool in research areas such as detection of chromosome variation, identification of allopolyploid, and deciphering of three-dimensional (3D) genome structures. Based on the demand for highly efficient oligo probes for oligo-FISH experiments, increasing numbers of tools have been developed for probe design in recent years. Obsolete oligonucleotide design tools have been adapted for oligo-FISH probe design because of their similar considerations. Read More

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Dual-imprinted organic/inorganic nanocomposite membranes with highly selective polydopamine-intimated nanostructures for pharmaceutically active compound separation.

J Colloid Interface Sci 2021 Jul 7;604:691-704. Epub 2021 Jul 7.

Institute of Green Chemistry and Chemical Technology, Advanced Chemical Engineering Laboratory of Green Materials and Energy of Jiangsu Province, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China.

Here, the graphene oxide (GO)/SiO-loaded dual-imprinted membranes (GS-DIMs) were constructed based on the self-polymerization imprinting technique of dopamine, in which a twice polydopamine (PDA)-based imprinting strategy had been successfully developed to obtain the three-dimensional nanocomposite membrane-based separation system. Meanwhile, the pollution-intensive antibiotics of tetracycline (TC) was used as template molecule throughout the GS-DIMs synthesis, and the dopamine molecules were simultaneously used as functional monomer and cross-linking agent during the twice polydopamine (PDA)-based imprinting processes. Therefore, dual-TC-imprinted sites had been prepared based on the as-designed dual imprinting processes, the as-prepared GS-DIMs-based separation system with dual-TC-imprinted structures could not only allow for the largely enhanced rebinding result of 65. Read More

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Inter-examiner Agreement in the Radiologic Identification of Apical Periodontitis/Rarefying Osteitis in the National Dental PBRN PREDICT Endodontic Study.

J Endod 2021 Jul 16. Epub 2021 Jul 16.

Kaiser Permanente Center for Health Research, Portland, OR.

Introduction: Periapical images are routinely made in endodontics to support diagnosis and treatment decisions, but conventional imaging may not readily demonstrate inflammatory changes. This study aims to 1) quantify disagreement in the radiologic interpretation of apical periodontitis/rarefying osteitis between 2 expert examiners; and 2) determine if differences exist based on anatomical location.

Methods: We used 1717 pre-treatment periapical images made prior to orthograde endodontic treatment as part of the Predicting Outcomes of Root Canal Treatment (PREDICT) study conducted within the National Dental Practice-Based Research Network. Read More

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Large Deformation and Energy Absorption Behaviour of Perforated Hollow Sphere Structures under Quasi-Static Compression.

Materials (Basel) 2021 Jul 2;14(13). Epub 2021 Jul 2.

School of Architecture and Urban Planning, Guangdong University of Technology, Guangzhou 510090, China.

Hollow sphere structures with perforations (PHSSs) in three different arrangements (simple cubic (SC), body-centred cubic (BCC), and face-centred cubic (FCC)) were fabricated through three-dimensional (3D) printing, and the mechanical behaviours of these PHSSs under quasi-static compression were investigated experimentally and numerically. The results indicated that under uniaxial compression, the PHSSs mainly undergo three stages, i.e. Read More

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Spin Crossover in a Series of Non-Hofmann-Type Fe(II) Coordination Polymers Based on [Hg(SeCN)] or [Hg(SeCN)] Building Blocks.

Inorg Chem 2021 Jul 19. Epub 2021 Jul 19.

College of Chemical and Chemical Engineering, Shandong University of Technology, Zibo 255049, People's Republic of China.

Self-assembly of [Hg(SeCN)] tetrahedral building blocks, iron(II) ions, and a series of bis-monodentate pyridyl-type bridging ligands has afforded the new heterobimetallic Hg-Fe coordination polymers {Fe[Hg(SeCN)](4,4'-bipy)} (), {Fe[Hg(SeCN)](tvp)} (), {Fe[Hg(SeCN)](4,4'-azpy)} (), {Fe[Hg(SeCN)](4,4'-azpy)(MeOH)} (), {Fe[Hg(SeCN)](3,3'-bipy)} () and {Fe[Hg(SeCN)](3,3'-azpy)} () (4,4-bipy = 4,4'-bipyridine, tvp = -1,2-bis(4-pyridyl)ethylene, 4,4'-azpy = 4,4'-azobispyridine, 3,3-bipy = 3,3'-bipyridine, 3,3'-azpy = 3,3'-azobispyridine). Single-crystal X-ray analyses show that compounds and display a two-dimensional robust sheet structure made up of infinite linear [(FeL)] (L = 4,4'-bipy or 4,4'-azpy) chains linked by formed {[Hg(L)(SeCN)]} anionic dimeric bridges. Complexes and - define three-dimensional networks with different topological structures, indicating, in combination with complexes and , that the polarity, length, rigidity, and conformation of the bridging organic ligand play important roles in the structural nature of the products reported here. Read More

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RNA 3D Structure Prediction Using Coarse-Grained Models.

Jun Li Shi-Jie Chen

Front Mol Biosci 2021 2;8:720937. Epub 2021 Jul 2.

Departments of Physics and Biochemistry, and Institute of Data Science and Informatics, University of Missouri, Columbia, MO, United States.

The three-dimensional (3D) structures of Ribonucleic acid (RNA) molecules are essential to understanding their various and important biological functions. However, experimental determination of the atomic structures is laborious and technically difficult. The large gap between the number of sequences and the experimentally determined structures enables the thriving development of computational approaches to modeling RNAs. Read More

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Retinal Organoids: Cultivation, Differentiation, and Transplantation.

Front Cell Neurosci 2021 28;15:638439. Epub 2021 Jun 28.

Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China.

Retinal organoids (ROs), which are derived from stem cells, can automatically form three-dimensional laminar structures that include all cell types and the ultrastructure of the retina. Therefore, they are highly similar to the retinal structure in the human body. The development of organoids has been a great technological breakthrough in the fields of transplantation therapy and disease modeling. Read More

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The Use of a 3D Printing Model in Planning a Donor Hepatectomy for Living Donor Liver Transplantation: First in India.

J Clin Exp Hepatol 2021 Jul-Aug;11(4):515-517. Epub 2020 Aug 19.

Integrated Liver Care Unit, Aster CMI Hospital, New Airport Road, Bangalore, 560092, India.

Introduction: Three-dimensional (3D) anatomical relationships between the hepatic veins and portal structures can serve as a guide to plan resections in donor hepatectomy during living donor liver transplantation. We present the first case report from India on the use of a 3D printed liver model, as an assist to living donor liver transplantation.

Methods: A 3D model of the donor liver with hepatic venous structures printed within it was prepared using image acquisition data. Read More

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Fabrication and Characterization of 3D Printed, 3D Microelectrode Arrays for Interfacing with a Peripheral Nerve-on-a-Chip.

ACS Biomater Sci Eng 2021 Jul 10;7(7):3018-3029. Epub 2020 Dec 10.

NanoScience Technology Center (NSTC), University of Central Florida, Orlando, Florida 32816, United States.

We present a nontraditional fabrication technique for the realization of three-dimensional (3D) microelectrode arrays (MEAs) capable of interfacing with 3D cellular networks . The technology uses cost-effective to fabricate the 3D MEAs with 3D printed base structures with the metallization of the microtowers and conductive traces being performed by stencil mask evaporation techniques. A biocompatible lamination layer insulates the traces for realization of 3D microtower MEAs (250 μm base diameter, 400 μm height). Read More

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External surface anatomy of the postfolding human embryo: Computer-aided, three-dimensional reconstruction of printable digital specimens.

Jon Jatsu Azkue

J Anat 2021 Jul 18. Epub 2021 Jul 18.

Department of Neurosciences, School of Medicine and Nursery, Universty of the Basque Country, UPV/EHU, Leioa, Bizkaia, Spain.

Opportunities for clinicians, researchers, and medical students to become acquainted with the three-dimensional (3D) anatomy of the human embryo have historically been limited. This work was aimed at creating a collection of digital, printable 3D surface models demonstrating major morphogenetic changes in the embryo's external anatomy, including typical features used for external staging. Twelve models were digitally reconstructed based on optical projection tomography, high-resolution episcopic microscopy and magnetic resonance imaging datasets of formalin-fixed specimens of embryos of developmental stages 12 through 23, that is, stages following longitudinal and transverse embryo folding. Read More

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Cuticular modified air sacs underlie white coloration in the olive fruit fly, Bactrocera oleae.

Commun Biol 2021 Jul 16;4(1):881. Epub 2021 Jul 16.

Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, Kiel, Germany.

Here, the ultrastructure and development of the white patches on thorax and head of Bactrocera oleae are analysed using scanning electron microscopy, transmission electron microscopy, and fluorescence microscopy. Based on these analyses and measurements of patch reflectance spectra, we infer that white patches are due to modified air sacs under transparent cuticle. These air sacs show internal arborisations with beads in an empty space, constituting a three-dimensional photonic solid responsible for light scattering. Read More

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Metastability relationship between two- and three-dimensional crystal structures: a case study of the Cu-based compounds.

Shota Ono

Sci Rep 2021 Jul 16;11(1):14588. Epub 2021 Jul 16.

Department of Electrical, Electronic and Computer Engineering, Gifu University, Gifu, 501-1193, Japan.

Some of the three-dimensional (3D) crystal structures are constructed by stacking two-dimensional (2D) layers. To study whether this geometric concept, i.e. Read More

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Digital Light Processing 3D Printing of Healable and Recyclable Polymers with Tailorable Mechanical Properties.

ACS Appl Mater Interfaces 2021 Jul 16. Epub 2021 Jul 16.

Beijing National Laboratory for Molecular Sciences, Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.

Three-dimensional (3D) printing is becoming a revolutionary technique across various fields. Especially, digital light processing (DLP) 3D printing shows advantages of high resolution and high efficiency. However, multifunctional monomers are commonly used to meet the rapid liquid-to-solid transformation during DLP printing, and the extensive production of unreprocessable thermosets will lead to resource waste and environmental problems. Read More

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