Geometrical & Interfacial Modulation of a Biomimetic Spinal Implant

2009 ◽  
Vol 4 ◽  
pp. 41-58
Author(s):  
P. Lok ◽  
Philip Boughton ◽  
T. Kishen ◽  
Ashish D. Diwan
Keyword(s):  
Surface Area ◽  
Axial Loading ◽  
Interfacial Stress ◽  
Implant Design ◽  
Tissue Remodelling ◽  
Design Elements ◽  
Spinal Implant ◽  
Form And Function ◽  
Spinal Disc ◽  
And Function

The nucleus of a spinal disc is seamlessly connective and protectively supportive of the joint within which it is enveloped. A range of nucleus prosthesis configurations have been proposed and applied with some success. Those that have demonstrated clinical efficacy have approximated physiological form and function using established biomaterials while preserving key anatomical structures. The minimally invasive biostable, biomimetic Columna Disc Device (CDD) partial spinal disc replacement has been developed to clinical trial stage. It mimics the geometry and response of the nucleus that it replaces. While the implant configuration and materials have been set, the geometry and interfacial properties of this prosthesis may be modulated to account for versatility in surgical deployment, implant stiffness, and subsequent long-term tissue remodelling response. FEA models were developed to study effects of implant jacket geometry and surface properties on implant deployment and biomechanics. Studded and dimpled textures provide a method for increasing surface area to diffuse jacket-filler interfacial stress and similar for the implant-tissue junction. Surface texture design elements observed in nature can protect against delamination and interlayer slippage. This is the case with adherent outer layers of human skin. A textured implant design is also proposed to guard against third body wear by housing debris remote of wear sites and by reducing sliding. The periodically varying strain fields provided by the textured jacket may also help mitigate for tears by diverting and arresting micro-fissures. Increasing friction at the implant-tissue interface to the point of tissue-attachment was shown to increase the stiffness of the implant in axial-loading. In contrast, increasing bulk surface area is expected to contribute to a decrease in implant stiffness. This is, however, dependent on the intimacy and properties of interfacing tissues.

scholarly journals Design principles of hair-like structures as biological machines

2018 ◽  
Vol 15 (142) ◽  
pp. 20180206 ◽  
Author(s):  
Madeleine Seale ◽  
Cathal Cummins ◽  
Ignazio Maria Viola ◽  
Enrico Mastropaolo ◽  
Naomi Nakayama
Keyword(s):  
Mechanical Properties ◽  
Surface Area ◽  
Large Surface Area ◽  
Structural Basis ◽  
Basic Design ◽  
Form And Function ◽  
Mechanical Unit ◽  
Wide Range ◽  
Range Of Functions ◽  
And Function

Hair-like structures are prevalent throughout biology and frequently act to sense or alter interactions with an organism's environment. The overall shape of a hair is simple: a long, filamentous object that protrudes from the surface of an organism. This basic design, however, can confer a wide range of functions, owing largely to the flexibility and large surface area that it usually possesses. From this simple structural basis, small changes in geometry, such as diameter, curvature and inter-hair spacing, can have considerable effects on mechanical properties, allowing functions such as mechanosensing, attachment, movement and protection. Here, we explore how passive features of hair-like structures, both individually and within arrays, enable diverse functions across biology. Understanding the relationships between form and function can provide biologists with an appreciation for the constraints and possibilities on hair-like structures. Additionally, such structures have already been used in biomimetic engineering with applications in sensing, water capture and adhesion. By examining hairs as a functional mechanical unit, geometry and arrangement can be rationally designed to generate new engineering devices and ideas.

scholarly journals Compliance of the fish outflow tract is altered by thermal acclimation through connective tissue remodelling

2021 ◽  
Vol 18 (184) ◽  
Author(s):  
Adam N. Keen ◽  
John J. Mackrill ◽  
Peter Gardner ◽  
Holly A. Shiels
Keyword(s):  
Ex Vivo ◽  
Gelatin Zymography ◽  
Thermal Acclimation ◽  
Outflow Tract ◽  
Tissue Remodelling ◽  
Fish Heart ◽  
Form And Function ◽  
Bulbus Arteriosus ◽  
Different Temperatures ◽  
And Function

To protect the gill capillaries from high systolic pulse pressure, the fish heart contains a compliant non-contractile chamber called the bulbus arteriosus which is part of the outflow tract (OFT) which extends from the ventricle to the ventral aorta. Thermal acclimation alters the form and function of the fish atria and ventricle to ensure appropriate cardiac output at different temperatures, but its impact on the OFT is unknown. Here we used ex vivo pressure–volume curves to demonstrate remodelling of passive stiffness in the rainbow trout ( Oncorhynchus mykiss ) bulbus arteriosus following more than eight weeks of thermal acclimation to 5, 10 and 18°C. We then combined novel, non-biased Fourier transform infrared spectroscopy with classic histological staining to show that changes in compliance were achieved by changes in tissue collagen-to-elastin ratio. In situ gelatin zymography and SDS-PAGE zymography revealed that collagen remodelling was underpinned, at least in part, by changes in activity and abundance of collagen degrading matrix metalloproteinases. Collectively, we provide the first indication of bulbus arteriosus thermal remodelling in a fish and suggest this remodelling ensures optimal blood flow and blood pressure in the OFT during temperature change.

scholarly journals Understanding geometrical features of Nuaulu shield design

2018 ◽  
Vol 24 (2) ◽  
pp. 210-231
Author(s):  
Roy Ellen
Keyword(s):  
Life Cycle ◽  
Design Elements ◽  
Geometric Characteristics ◽  
Form And Function ◽  
Geometrical Features ◽  
Limited Application ◽  
And Function ◽  
The Impact ◽  
Shield Design

This article seeks to elucidate the form and function of decorative designs on Nuaulu parrying shields from Seram, Indonesia. It builds on earlier work focusing on the shield as a sacred anthropomorphized entity with its own life-cycle, the reproduction of which mirrors the reproduction of sacred houses. It has previously been suggested that diversity in design elements is deliberately cultivated as part of a general aesthetic, connecting individuality, personhood and effervescence as features of living entities. Here the author examines the materiality of shields, documenting variation in design – especially patterns of ceramic and shell discs – and asks what significance should be attached to these. He concludes that the attribution of specific meanings to individual elements is of limited application, while the impact of the shields lies in variation itself, the perceptual affects shields have on viewers, and in abstract geometric characteristics that make them fit for ritual purpose.

Scanning tunneling microscopy (STM) of DNA and RNA

1989 ◽  
Vol 47 ◽  
pp. 34-35
Author(s):  
Patricia G. Arscott ◽  
Gil Lee ◽  
Victor A. Bloomfield ◽  
D. Fennell Evans
Keyword(s):  
Molecular Structures ◽  
Inorganic Materials ◽  
Resolving Power ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Form And Function ◽  
Dna And Rna ◽  
Calf Thymus ◽  
And Function ◽  
The Relationship

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).

Re-examining the form and function of superstition

2011 ◽  
Author(s):  
Scott Fluke ◽  
Russell J. Webster ◽  
Donald A. Saucier
Keyword(s):  
Form And Function ◽  
And Function
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