Mason N Dean

Mason N Dean
City University of Hong Kong | CityU · Department of Infectious Diseases & Public Health

PhD

About

131
Publications
42,566
Reads
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2,267
Citations
Additional affiliations
November 2017 - January 2021
Max Planck Institute of Colloids & Interfaces
Position
  • Group Leader
January 2011 - October 2017
Max-Planck-Institut für Kolloid- und Grenzflächenforschung
Position
  • Group Leader
September 2003 - September 2009
University of California, Irvine

Publications

Publications (131)
Article
The endoskeleton of elasmobranchs (sharks and rays) is comprised largely of unmineralized cartilage, differing fundamentally from the bony skeletons of other vertebrates. Elasmobranch skeletons are further distinguished by a tessellated surface mineralization, a layer of minute, polygonal, mineralized tiles called tesserae. This ‘tessellation’ has...
Article
Full-text available
Faced with a comparatively limited palette of minerals and organic polymers as building materials, evolution has arrived repeatedly on structural solutions that rely on clever geometric arrangements to avoid mechanical trade-offs in stiffness, strength and flexibility. In this tutorial review, we highlight the concept of tessellation, a structural...
Article
Full-text available
A remarkable property of tetrapod bone is its ability to detect and remodel areas where damage has accumulated through prolonged use. This process, believed vital to the long-term health of bone, is considered to be initiated and orchestrated by osteocytes, cells within the bone matrix. It is therefore surprising that most extant fishes (neoteleost...
Article
Sharks, rays and other elasmobranch fishes are characterized by a skeletal type that is unique among living vertebrates, comprised predominantly of an unmineralized cartilage, covered by a thin outer layer of sub-millimeter, mineralized tiles called tesserae. As the mineralized portion of the skeleton appears to grow only by apposition, adding mate...
Article
We question two major tenets of bone biology: that the primary role of remodelling is to remove damage in the bone (so-called damage-driven remodelling) and that osteocytes are the only strain-sensing orchestrators of this process. These concepts are distilled largely from research on model mammal species, but in fact, there are a number of feature...
Preprint
Full-text available
3D shapes provide substantially more information than 2D images. However, the acquisition of 3D shapes is sometimes very difficult or even impossible in comparison with acquiring 2D images, making it necessary to derive the 3D shape from 2D images. Although this is, in general, a mathematically ill-posed problem, it might be solved by constraining...
Article
Full-text available
From large ventral pleats of humpback whales to nanoscale ridges on flower petals, wrinkled structures are omnipresent, multifunctional, and found at hugely diverse scales. Depending on the particulars of the biological system-its environment, morphology, and mechanical properties-wrinkles may control adhesion, friction, wetting, or drag; promote i...
Article
Full-text available
Biological armors derive their mechanical integrity in part from their geometric architectures, often involving tessellations: individual structural elements tiled together to form surface shells. The carapace of boxfish, for example, is composed of mineralized polygonal plates, called scutes, arranged in a complex geometric pattern and nearly comp...
Article
Habitat transitions are key potential explanations for why some lineages have diversified and others have not - from Anolis lizards to Darwin's finches. The ecological ramifications of marine-to-freshwater transitions for fishes suggest evolutionary contingency: some lineages maintain their ancestral niches in novel habitats (niche conservatism), w...
Article
Full-text available
During crucial growth stages of vertebrate long bones, calcified cartilage beneath the growth plate is anchored to bone by a third mineralized component, the cement line. Proper skeletal development is contingent on the interplay of these three constituents, yet their mineralization processes and structural interactions are incompletely understood,...
Article
Full-text available
Tessellated cartilage is a distinctive composite tissue forming the bulk of the skeleton of cartilaginous fishes (e.g. sharks and rays), built from unmineralized cartilage covered at the surface by a thin layer of mineralized tiles called tesserae. The finescale structure and composition of elasmobranch tessellated cartilage has largely been invest...
Article
Full-text available
Breast cancer frequently metastasizes to bone, causing osteolytic lesions. However, how factors secreted by primary tumors affect the bone microenvironment before the osteolytic phase of metastatic tumor growth remains unclear. Understanding these changes is critical as they may regulate metastatic dissemination and progression. To mimic premetasta...
Article
Full-text available
Members of the Chondrichthyes (Elasmobranchii and Holocephali) are distinguished by their largely cartilaginous endoskeletons, which comprise an uncalcified core overlain by a mineralized layer; in the Elasmobranchii (sharks, skates, rays) most of this mineralization takes the form of calcified polygonal tiles known as tesserae. In recent years, th...
Article
Full-text available
The teeth of all vertebrates predominantly comprise the same materials, but their lifespans vary widely: in stark contrast to mammals, shark teeth are functional only for weeks, rather than decades, making lifelong durability largely irrelevant. However, their diets are diverse and often mechanically demanding, and as such, their teeth should maint...
Article
Full-text available
An accepted uniting character of modern cartilaginous fishes (sharks, rays, chimaera) is the presence of a mineralized, skeletal crust, tiled by numerous minute plates called tesserae. Tesserae have, however, never been demonstrated in modern chimaera and it is debated whether the skeleton mineralizes at all. We show for the first time that tessell...
Article
Skeletal bone enlargement (hyperossification) was thought to only occur in endochondral and dermal bones (e.g., endoskeletons of marine tetrapods and dermal bones of certain jawless vertebrates, placoderms, and teleost fishes). However, in some arthrodiran placoderms (basal jawed vertebrates), i.e., Millerosteus minor, Compagopiscis croucheri, East...
Preprint
Full-text available
Chondrichthyes (Elasmobranchii and Holocephali) are distinguished by their largely cartilaginous endoskeleton that comprises an uncalcified core overlain by a mineralised layer; in the Elasmobranchii (sharks, skates, rays) this mineralisation takes the form of calcified polygonal tiles known as tesserae. In recent years, these skeletal tissues have...
Article
Full-text available
When describing the architecture and ultrastructure of animal skeletons, introductory biology, anatomy and histology textbooks typically focus on the few bone and cartilage types prevalent in humans. In reality, cartilage and bone are far more diverse in the animal kingdom, particularly within fishes (Chondrichthyes and Actinopterygii), where carti...
Article
Full-text available
A prerequisite for many analysis tasks in modern comparative biology is the segmentation of 3-dimensional (3D) images of the specimens being investigated (e.g. from microCT data). Depending on the specific imaging technique that was used to acquire the images and on the image resolution, different segmentation tools are required. While some standar...
Article
In most vertebrates the embryonic cartilaginous skeleton is replaced by bone during development. During this process, cartilage cells (chondrocytes) mineralize the extracellular matrix and undergo apoptosis, giving way to bone cells (osteocytes). In contrast, sharks and rays (elasmobranchs) have cartilaginous skeletons throughout life, where only t...
Article
Sharks and rays have distinctive skeletons among vertebrate animals, consisting primarily of unmineralized cartilage wrapped in a surface tessellation of minute polygonal tiles called tesserae, linked by unmineralized collagenous fibers. The discrete combination of hard and soft tissues is hypothesized to enhance the mechanical performance of tesse...
Article
Full-text available
Man-made armors often rely on rigid structures for mechanical protection, which typically results in a trade-off with flexibility and maneuverability. Chitons, a group of marine mollusks, evolved scaled armors that address similar challenges. Many chiton species possess hundreds of small, mineralized scales arrayed on the soft girdle that surrounds...
Conference Paper
A load frame for in situ mechanical testing is developed for the microtomography end stations at the imaging beamline P05 and the high-energy material science beamline P07 of PETRA III at DESY, both operated by the Helmholtz-Zentrum Geesthacht. The load frame is fully integrated into the beamline control system and can be controlled via a feedback...
Article
Research into biological materials often centers on the impressive material properties produced in Nature. In the process, however, this research often neglects the ecologies of the materials, the organismal contexts relating to how a biological material is actually used. In biology, materials are vital to organismal interactions with their environ...
Article
Full-text available
Various 3D imaging techniques are routinely used to examine biological materials, the results of which are usually a stack of grayscale images. In order to quantify structural aspects of the biological materials, however, they must first be extracted from the dataset in a process called segmentation. If the individual structures to be extracted are...
Article
Skeletal tissues are built and shaped through complex, interacting active and passive processes. These spatial and temporal variabilities make interpreting growth mechanisms from morphology difficult, particularly in bone, where the remodeling process erases and rewrites local structural records of growth throughout life. In contrast to the majorit...
Chapter
Fishes, and elasmobranchs in particular, are often described as “opportunistic” predators meaning that they will take advantage of feeding opportunities as they arise. The implication of this term is that elasmobranchs are not selective about what they eat, which is a gross oversimplification of the complex interactions that shape diet, many of whi...
Article
Full-text available
Osteocytes, cells forming an elaborate network within the bones of most vertebrate taxa, are thought to be the master regulators of bone modeling, a process of coordinated, local bone-tissue deposition and removal that keeps bone strains at safe levels throughout life. Neoteleost fish, however, lack osteocytes and yet are known to be capable of bon...
Data
Young’s moduli derived from nanoindentation of the vertebral body of swim-trained and untrained medaka and zebrafish. N = 30–65 indents from 3 fish of each group. Quantitative data were compared between groups by the nonparametric Mann–Whitney test, with the level of significance set at P ≤ 0.05. All original measurements of Young’s moduli determin...
Data
List of primers used. (DOCX)
Data
Swim training. (a) Medaka swim trained against a water current with tightly controlled (26 cm/s) velocity. Note that fish are swimming against the current, station-holding, and not turning. (b) Untrained (control) medaka swimming in a similar-sized chamber as the swim-training chamber, with minimal speed water flow (only sufficient for maintaining...
Data
Sequencing results of the MO-injected transcript compared with the medaka genome. The primer sequences used are shown in red letters. The exon parts are highlighted in blue, and the intron parts are highlighted in yellow. A stop codon present on the intron that was retained is highlighted in red. The sequencing shows that a significant portion of t...
Data
Musculature and bone in the caudal region of medaka. Caudal is to the right in all images. (a) Sagittal section of a 3D reconstruction of contrast-enhanced (PTA) tomography showing the dense musculature surrounding the caudal vertebral column of medaka. One vertebra is segmented in white to show the full 3D muscle–vertebral relationship. The caudal...
Data
Distribution of fish lengths (mm) in the first swimming experiment. No significant difference was found between untrained and trained fish of either species. There was a significant difference between medaka and zebrafish average lengths; as a result, higher swimming speeds were used for zebrafish in swimming experiments. (TIF)
Data
ISH results for 2 vertebral regions in zebrafish. Top row: NS; bottom row: intervertebral J. Each row comprises (from left to right) a multichannel RGB double fluorescent ISH image, followed by isolated single-channel images: DAPI, collagen (col1a1 = top row, col2a1 = bottom row), SOST. The figure provides a deconstruction of the multichannel ISH i...
Data
Underlying numeric data used in this work. (XLSX)
Data
ISH results for 2 vertebral regions in medaka. Top row: NS and adjacent fin R; bottom row: intervertebral J. Each row comprises (from left to right) a multichannel RGB double fluorescent ISH image, followed by isolated single-channel images (DAPI, col1, col2, respectively) and a SOST ISH image. The figure provides a deconstruction of the multichann...
Data
List of ages of medaka used in different experiments. All original measurements of the total length of the fish participating in the different experimental groups are presented in S1 Data. (DOCX)
Chapter
When describing the architecture and ultrastructure of animal skeletons, introductory biology, anatomy and histology textbooks typically focus on the few bone and cartilage types prevalent in humans. In reality, cartilage and bone are far more diverse in the animal kingdom, particularly within fishes, where cartilage and bone types exist that are c...
Article
Background Successful transcatheter aortic valve replacement (TAVR) requires an understanding of how a prosthetic valve will interact with a patient's anatomy in advance of surgical deployment. To improve this understanding, we developed a benchtop workflow that allows for testing of physical interactions between prosthetic valves and patient-speci...
Article
Full-text available
Three-dimensional (3D) printing technologies are increasingly used to convert medical imaging studies into tangible (physical) models of individual patient anatomy, allowing physicians, scientists, and patients an unprecedented level of interaction with medical data. To date, virtually all 3D-printable medical data sets are created using traditiona...
Article
Full-text available
Introduction Many biological structures show recurring tiling patterns on one structural level or the other. Current image acquisition techniques are able to resolve those tiling patterns to allow quantitative analyses. The resulting image data, however, may contain an enormous number of elements. This renders manual image analysis infeasible, in p...
Data
Supplementary video from 'Large batoid fishes frequently consume stingrays despite skeletal damage': Video showing annotated renderings of CT scan data used in this study. Note the many stingray spines embedded in the jaw (visible at ~00:29) and the loose, mineralized callus tissue that has grown up to encase spines (visible in the high resolution...
Article
Full-text available
The shapes of vertebrate teeth are often used as hallmarks of diet. Here, however, we demonstrate evidence of frequent piscivory by cartilaginous fishes with pebble-like teeth that are typically associated with durophagy, the eating of hard-shelled prey. High-resolution micro-computed tomography observation of a jaw specimen from one batoid species...
Article
The primary skeletal tissue in elasmobranchs -sharks, rays and relatives- is cartilage, forming both embryonic and adult endoskeletons. Only the skeletal surface calcifies, exhibiting mineralized tiles (tesserae) sandwiched between a cartilage core and overlying fibrous perichondrium. These two tissues are based on different collagens (Coll II and...
Article
Full-text available
Protein-based biogenic materials provide important inspiration for the development of high-performance polymers. The fibrous mussel byssus, for instance, exhibits exceptional wet adhesion, abrasion resistance, toughness and self-healing capacity–properties that arise from an intricate hierarchical organization formed in minutes from a fluid secreti...
Article
Nature produces a multitude of composite materials with intricate architectures that in many instances far exceed the performance of their modern engineering analogs. Despite significant investigations into structure-function relationships of complex biological materials, there is typically a lack of critical information regarding the specific func...
Article
The cartilaginous endoskeletons of Elasmobranchs (sharks and rays) are reinforced superficially by minute, mineralized tiles, called tesserae. Unlike the bony skeletons of other vertebrates, elasmobranch skeletons have limited healing capability and their tissues’ mechanisms for avoiding damage or managing it when it does occur are largely unknown....
Article
Tilings are constructs of repeated shapes covering a surface, common in both manmade and natural structures, but in particular are a defining characteristic of shark and ray skeletons. In these fishes, cartilaginous skeletal elements are wrapped in a surface tessellation, comprised of polygonal mineralized tiles linked by flexible joints, an arrang...
Article
Full-text available
Macroscopic, periodic, dark and bright patterns are observed on sections of elephant tusk, in the dentin part (ivory). The motifs—also called Schreger pattern—vary depending on the orientation in the tusk: on sections perpendicular to the tusk axis, a checkerboard pattern is present whereas on sections longitudinal to it, alternating stripes are ob...
Data
Schreger pattern of the transverse plane. (PDF)
Data
Details on the modeling of the two cubes. (PDF)
Data
Document for the acquisition of the elephant tusk. (PDF)
Data
Influence of light on the origin of the Schreger pattern. (PDF)
Data
Virtual cut through an array of helical (or sinusoidal) tubules obtained through a series of successive cuts through individual tubules. (PDF)
Data
Quantitative 2D elemental chemical maps of the transverse section of elephant ivory. (PDF)
Data
Average dot spacing and coordinates of tubule cross-sections of a tangential fractured section of elephant ivory and description of the modeling of the two cubes of straight tubules. (PDF)
Data
Tubular sinusoidal trend of the transverse plane. (PDF)
Data
Tubular cross-section arrangement and shape in the tangential plane. (PDF)
Data
SR-μCT data of the 40 mm3 volume with 1 μm resolution (voxel-size). (PDF)
Data
SR-μCT data of the 5.10−4 mm3 volume with 0.4 μm resolution (voxel-size). (PDF)
Data
Influence of light on the origin of the Schreger pattern. (PDF)
Data
Detailed description of the 2D slices obtained by virtually cutting the 3D models. (PDF)
Chapter
Although the clades of cartilaginous fishes can be broadly considered to share a generalized skeletal bodyplan comprised of the same elements, their skeletons exhibit clade-specific arrangements and morphologies.
Chapter
Most adult vertebrate animals have bony skeletons, with cartilage mostly restricted to joints and flexible structures. In contrast, the Chondrichthyes (sharks, batoids, and chimaeras) have endoskeletons made entirely of cartilage. Moreover, in sharks and batoids, most of the skeletal cartilage is tessellated, covered with mineralized, subperichondr...
Article
Full-text available
All stingrays in the family Myliobatidae are durophagous, consuming bivalves and gastropods, as well as decapod crustaceans. Durophagous rays have rigid jaws, flat teeth that interlock to form pavement-like tooth plates, and large muscles which generate bite forces capable of fracturing stiff biological composites (e.g., mollusk shell). The relativ...