Background: Biological structures grow spontaneously from a seed, using materials supplied by the environment. These structures are hierarchical, with the 'building blocks' on each level constructed from those on the lower level. To understand and model the processes that occur on many levels, and later construct them, is a difficult task. However interest in this subject is growing. It is now possible to study the spontaneous growth of hierarchical structures in simple, two component chemical systems.
Results: Aluminum-silicate systems have been observed to grow into structures that are approximately conical. These structures are composed of multiple smaller cones with several hierarchical levels of complexity. On the highest level the system resembles a metropolis, with a horizontal resource distribution network connecting vertical, conical structures. The cones are made from many smaller cones that are connected together forming a whole with unusual behavior. The growth is observed to switch periodically between the vertical and horizontal directions.
Conclusion: A structure grown in a dish is observed to have many similarities to other hierarchical systems such as biological organisms or cities. This system may provide a simple model system to search for universal laws governing the growth of complex hierarchical structures. Graphical AbstractSide view of the chemical structure made from many vertical cones to form a chemical metropolis. The tallest structure is 17 cm high.
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http://dx.doi.org/10.1186/s13322-015-0007-9 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
University of Fribourg: Universite de Fribourg, Department of Chemistry, Chemin du Musée 9, 1700, Fribourg, SWITZERLAND.
The recovery and separation of organic solvents is highly important for the chemical industry and environmental protection. In this context, porous organic polymers (POPs) have significant potential owing to the possibility of integrating shape-persistent macrocyclic units with high guest selectivity. Here, we report the synthesis of a macrocyclic porous organic polymer (np-POP) and the corresponding model compound by reacting cyclotetrabenzil naphthalene octaketone macrocycle with 1,2,4,5-tetraaminobenzene and 1,2-diaminobenzene, respectively, under solvothermal conditions.
View Article and Find Full Text PDFACS Nano
January 2025
Center for Innovation & Precision Dentistry, School of Dental Medicine, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Microrobots are poised to transform biomedicine by enabling precise, noninvasive procedures. However, current magnetic microrobots, composed of solid monolithic particles, present fundamental challenges in engineering intersubunit interactions, limiting their collective effectiveness in navigating irregular biological terrains and confined spaces. To address this, we design hierarchically assembled microrobots with multiaxis mobility and collective adaptability by engineering the potential magnetic interaction energy between subunits to create stable, self-reconfigurable structures capable of carrying and protecting cargo internally.
View Article and Find Full Text PDFUnlabelled: Sensory stimuli vary across a variety of dimensions, like contrast, orientation, or texture. The brain must rely on population representations to disentangle changes in one dimension from changes in another. To understand how the visual system might extract separable stimulus representations, we recorded multiunit neuronal responses to texture images varying along two dimensions: contrast, a property represented as early as the retina, and naturalistic statistical structure, a property that modulates neuronal responses in V2 and V4, but not in V1.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Biochemistry and Molecular Biology, Life Science Faculty, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, 8100, Bangladesh.
Multiple Sclerosis (MS) is an autoimmune and chronic disease in the brain and spinal cord. MS has inflammatory progression characterized by its hallmark inflammatory plaques. The histological and clinical characteristics of MS are shared by Experimental Autoimmune Encephalomyelitis (EAE).
View Article and Find Full Text PDFGene
January 2025
Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Kitaku, Tsushimanaka, Okayama 700-8530, Japan; Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, 3-1-1 Kitaku, Tsushimanaka, Okayama 700-8530, Japan. Electronic address:
Bird contour feathers exhibit a complex hierarchical structure composed of a rachis, barbs, and barbules, with barbules playing a crucial role in maintaining feather structure and function. Understanding the molecular mechanisms underlying barbule formation is essential for advancing our knowledge of avian biology and evolution. In this study, we identified a novel gene, pennaceous barbule cell factor (PBCF), using microarray analysis, RT-PCR, and in situ hybridization.
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