Mechanical Neural Growth Models

2005 ◽  
Author(s):  
Kathleen B. Allen ◽  
Bradley E. Layton
Keyword(s):  
De Novo ◽  
Mechanical Load ◽  
Growth Models ◽  
Growth Patterns ◽  
Polar Structure ◽  
Structural Support ◽  
Inner Surface ◽  
Neural Growth ◽  
Free Environment ◽  
Β Tubulin

Critical to being able to control the growth patterns of cell-based sensors is being able to understand how the cytoskeleton of the cell maintains its structure and integrity both under mechanical load and in a load-free environment. Our approach to a better understanding of cell growth is to use a computer simulation that incorporates the primary structures, microtubules, necessary for growth along with their observed behaviors and experimentally determined mechanical properties. Microtubules are the main compressive structural support elements for the axon of a neuron and are created via polymerization of α-β tubulin dimers. Our de novo simulation explores the mechanics of the forces between microtubules and the membrane. We hypothesize that axonal growth is most influenced by the location and direction of the force exerted by the microtubule on the membrane, and furthermore that the interplay of forces between microtubules and the inner surface of the cell membrane dictates the polar structure of axons. The simulation will be used to understand cytoskeletal mechanics for the purpose of engineering cells to be used as sensors.

scholarly journals Modelling growth curves of the normal infant’s mandible: 3D measurements using computed tomography

2021 ◽  
Author(s):  
Jan Aart M. Schipper ◽  
Manouk J. S. van Lieshout ◽  
Stefan Böhringer ◽  
Bonnie L. Padwa ◽  
Simon G. F. Robben ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Growth Models ◽  
Normal Growth ◽  
Growth Patterns ◽  
Ct Scans ◽  
Mandibular Ramus ◽  
Linear Measurements ◽  
Mandibular Growth ◽  
Gonial Angle ◽  
Mandibular Body

Abstract Objectives Data on normal mandibular development in the infant is lacking though essential to understand normal growth patterns and to discriminate abnormal growth. The aim of this study was to provide normal linear measurements of the mandible using computed tomography performed in infants from 0 to 2 years of age. Material and methods 3D voxel software was used to calculate mandibular body length, mandibular ramus length, bicondylar width, bigonial width and the gonial angle. Intra- and inter-rater reliability was assessed for these measurements. They were found to be sufficient for all distances; intra-class correlation coefficients were all above 0.9. Regression analysis for growth modelling was performed. Results In this multi-centre retrospective study, 109 CT scans were found eligible that were performed for various reasons (e.g. trauma, craniosynostosis, craniofacial abscesses). Craniosynostosis patients had larger mandibular measurements compared to non-craniosynostosis patients and were therefore excluded. Fifty-one CT scans were analysed. Conclusions Analysis showed that the mandible increases more in size vertically (the mandibular ramus) than horizontally (the mandibular body). Most of the mandibular growth occurs in the first 6 months. Clinical relevance These growth models provide insight into normal mandibular development in the first 2 years of life. This reference data facilitates discrimination between normal and abnormal mandibular growth.

High Strength Conductors and Structural Materials for High Field Magnets

MRS Advances ◽  
2016 ◽  
Vol 1 (17) ◽  
pp. 1233-1239 ◽  
Author(s):  
Ke Han ◽  
Rongmei Niu ◽  
Jun Lu ◽  
Vince Toplosky
Keyword(s):  
Service Life ◽  
High Field ◽  
Lattice Distortion ◽  
Mechanical Load ◽  
Cold Deformation ◽  
High Strength ◽  
Structural Support ◽  
Metal Metal ◽  
Lattice Distortions ◽  
Materials Used

ABSTRACTOne important approach to increasing High magnetic fields (HMF) beyond what is now possible is to improve the properties of various composite materials used as both conductors and structural support. Typical conductors for high field magnets are Cu-based metal-metal composites. To achieve high mechanical strength, these composites are fabricated by cold deformation, which introduces high densities of interfaces along with lattice distortions. During the operation of a magnet, mechanical load, high magnetic field, extreme temperatures and other stressors are imposed on the materials, causing them to be further “processed”. The composite conductors in a magnet, for example, may undergo high temperatures, which reduce lattice distortions or soften the material. At the same time, HMF may increase lattice distortion, leading to a complex change in interface characteristics. Both the mechanical properties of the conductors, like the tensile and yield strength, and the electric conductivity of the composites are closely connected to changes in lattice distortion and interface density. Understanding these changes helps us to assure that materials can operate in optimized conditions during most of magnets’ service life. Maximizing service life is critical, given the high cost of building and operating high field magnets. The goal of this paper is to 1) show our understanding of changes that occur in the properties of selected materials during the fabrication and under HMF and 2) to discuss how those changes relate to the microstructure of these materials and consequently to the service life of high field magnets.

Growth of Grey Kangaroos and the Reliablility of Age Determination from Body Measurements III. Interspecific Comparisions between Eastern and Western Grey Kangaroos, Macropus giganteus and M. fuliginosus

1984 ◽  
Vol 11 (1) ◽  
pp. 11 ◽  
Author(s):  
WE Poole ◽  
SM Carpenter ◽  
JT Wood
Keyword(s):  
Growth Models ◽  
Age Determination ◽  
Growth Patterns ◽  
Adult Size ◽  
Body Measurements ◽  
Foot Length ◽  
The Common ◽  
Rates Of Growth ◽  
Body Parameters

Seven body measurements were taken at regular intervals throughout life from both male and female eastern and western grey kangaroos. Evaluation of the reliability of criteria for determination of age and some aspects of the growth models for the two species were presented in earlier papers in this series. In this paper the common patterns and relationships between species in the growth characteristics of their body parameters are described and analysed. Comparison is made between species and sexes of rates of growth and size attained both within the pouch and following vacation of the pouch. Head, arm, leg and foot length were important discriminators, particularly when contrasted in various ways to summarize different body proportions. The insular form M.f. fuliginosus readily separated from the mainland forms, and M.f. ocydromus showed some differences which were related to its longer pouch life. Hybrid animals showed growth patterns intermediate to those of their parents. Sexual dimorphism in patterns ofgrowth was not detected during pouch life but was exhibited by all species after the young vacated the pouch and grew towards their full adult size.

scholarly journals Structural and molecular micropatterning of dual hydrogel constructs for neural growth models using photochemical strategies

2012 ◽  
Vol 15 (1) ◽  
pp. 49-61 ◽  
Author(s):  
Elaine L. Horn-Ranney ◽  
J. Lowry Curley ◽  
Gary C. Catig ◽  
Renee M. Huval ◽  
Michael J. Moore
Keyword(s):  
Growth Models ◽  
Neural Growth

Local Non-Affine Deformations and Fiber Kinematics of Elastomeric Electrospun Scaffolds

2007 ◽  
Author(s):  
Todd D. Courtney ◽  
Jun Liao ◽  
William R. Wagner ◽  
Michael S. Sacks
Keyword(s):  
Mechanical Response ◽  
De Novo ◽  
Mechanical Load ◽  
Strain Analysis ◽  
Fiber Network ◽  
Mechanical Responses ◽  
Electrospun Scaffolds ◽  
Global Strain

For most tissue engineering applications that seek to generate tissue de novo, the scaffold is the first step in a series of important developmental considerations. Whether synthetic or natural, scaffolds developed for immediate in vivo use must have mechanical properties comparable to the native tissue for at least the minimum time necessary for the accompanying seeded cells, and eventual cells that migrate in, to lay down an equivalent supporting matrix. Scaffolds developed for the purpose of growing a tissue in vitro, with eventual in vivo use, need not necessarily meet these mechanical requirements. However, to better develop new tissues in bioreactors or in vivo, it is pertinent to understand how the fiber network changes under some regimen of mechanical load, in essence to understand what the cell witnesses within the scaffold. Extending our previous work, which focused on measuring and modeling the mechanical response of electrospun poly ester urethane urea (es-PEUU) scaffolds [1], we investigated the intricate and detailed es-PEUU fiber networks that are created during scaffold synthesis and how these networks change under various levels of strain. Specifically, we focused on several scaffold responses to strain: 1) Characteristics of fiber tortuosity, which when increased can yield delayed onset of scaffold stiffness as well as other varying mechanical responses. 2) Fiber splay, which determines the orientation of the all fibers within the scaffold. 3) Local vs global strain analysis to determine whether the scaffolds follow affine or non-affine deformations. 4) Fiber strain, to investigate how increasing levels of scaffold strain are transmitted to local fibers. 5) Changes in fiber tortuosity and overall fiber directions under strain.

Comparative Cephalometric Study of Nasal Cavity Growth Patterns in Seven Animal Models

1994 ◽  
Vol 31 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Albert Losken ◽  
Mark P. Mooney ◽  
Michael I. Siegel
Keyword(s):  
Animal Models ◽  
Nasal Cavity ◽  
Rhesus Monkeys ◽  
Growth Models ◽  
Cavity Growth ◽  
Shape Index ◽  
Growth Patterns ◽  
X Rays ◽  
Cross Sectional ◽  
Somatic Development

Although primates have been the craniofacial growth models of choice, recent circumstances have stimulated the search for nonprimate models. In a series of studies we have described changes in various regions of the craniofacial complex for seven commonly used animal models. The present study examined the bony nasal cavity. One hundred and forty-four serial and cross-sectional lateral head x-rays were obtained for unoperated controls from previous growth studies. The sample consisted of data from 26 rats, 21 rabbits, 21 domestic cats, 23 domestic dogs, 17 baboons, 16 rhesus monkeys, and 20 chimpanzees. Comparative human data was taken from the Bolton Standards. The samples were divided into three age categories based on dental and somatic development. Midsagittal nasal cavity measurements included length, height, shape index, and area. Analysis was based on the percent increase in measures from the Infant condition. Three major shapes were discerned at adulthood (1) vertical quadrangles (humans and cats); (2) triangles (chimpanzees, rhesus monkeys, and baboons), and (3) horizontal quadrangles (rabbits, rats, and dogs). Results showed that overall shape was best modeled by the chimpanzee and, as a nonprimate model, the laboratory cat. Rabbits and rats also showed similar percent changes for length or height dimensions at different ages, suggesting that these animals may be acceptable, inexpensive alternatives to primates in some experimental situations.

Age and growth estimates of the jumbo flying squid (Dosidicus gigas) off Peru

2019 ◽  
Vol 32 ◽  
pp. 7
Author(s):  
Carlos Goicochea-Vigo ◽  
Enrique Morales-Bojórquez ◽  
Viridiana Y. Zepeda-Benitez ◽  
José Ángel Hidalgo-de-la-Toba ◽  
Hugo Aguirre-Villaseñor ◽  
...  
Keyword(s):  
Growth Model ◽  
Growth Pattern ◽  
Growth Models ◽  
Information Criterion ◽  
Growth Patterns ◽  
Age And Growth ◽  
Dosidicus Gigas ◽  
Asymptotic Growth ◽  
Schnute Model ◽  
Gompertz Growth Model

Mantle length (ML) and age data were analyzed to describe the growth patterns of the flying jumbo squid, Dosidicus gigas, in Peruvian waters. Six non-asymptotic growth models and four asymptotic growth models were fitted. Length-at-age data for males and females were analysed separately to assess the growth pattern. Multi-model inference and Akaike's information criterion were used to identify the best fitting model. For females, the best candidate growth model was the Schnute model with L∞ = 106.96 cm ML (CI 101.23–110.27 cm ML, P < 0.05), age at growth inflection 244.71 days (CI 232.82–284.86 days, P < 0.05), and length at growth inflection 57.26 cm ML (CI 55.42–58.51 cm ML, P < 0.05). The growth pattern in males was best described by a Gompertz growth model with L∞ = 127.58 cm ML (CI 115.27–131.80 cm ML, P < 0.05), t0 = 21.8 (CI 20.06–22.41, P < 0.05), and k = 0.007 (CI 0.006–0.007, P < 0.05). These results contrast with the growth model previously reported for D. gigas in the region, where the growth pattern was identified as non-asymptotic.

The Co-development of Reading and Attention from Middle Childhood to Early Adolescence: A Multivariate Latent Growth Curve Study

2020 ◽  
Author(s):  
Sally A. Larsen ◽  
Callie Little ◽  
William Coventry
Keyword(s):  
Reading Comprehension ◽  
Early Adolescence ◽  
Middle Childhood ◽  
Growth Models ◽  
Strong Predictor ◽  
Community Sample ◽  
Growth Patterns ◽  
Latent Growth ◽  
School Students ◽  
Latent Growth Models

Attention skills are a strong predictor of reading comprehension from childhood through to adolescence. However, less is known about the developmental relations between these two domains across this period. This study examined the co-development of reading and attention in a community sample of 614 Australian school students. Reading and attention were assessed biennially at ages 8, 10, 12 and 14. Results of univariate latent growth models demonstrated, on average, curvilinear trajectories for reading in which rapid growth across younger age spans decelerates as children reach adolescence. By contrast, attention behaviors followed a gradually increasing linear trajectory with significant inter-individual variation in development. Significant negative correlations were observed between the intercept and slope factors in both reading (r=-.62) and attention models (r=-.39) suggesting compensatory growth patterns in which poorer performing students in both domains at age 8 have steeper trajectories than their higher performing peers. Multivariate latent growth models examined the interrelatedness of reading and attention, controlling for gender and socioeconomic status. Reading comprehension and attention were positively correlated a) at the intercept (r=.54) indicating an association between better attention and higher reading achievement at age 8; and b) in the slope, such that reading growth was positively correlated with increasing attentive behaviors over time (r=.38). Evidence for the co-development of reading and attention provides support for the multiple deficit model theory, and suggests that developing attention capability could be one focus of attempts to improve reading attainment in early adolescence.

scholarly journals Resting heart rate and the development of antisocial behavior from age 9 to 14: Genetic and environmental influences

2009 ◽  
Vol 21 (3) ◽  
pp. 939-960 ◽  
Author(s):  
Laura A. Baker ◽  
Catherine Tuvblad ◽  
Chandra Reynolds ◽  
Mo Zheng ◽  
Dora Isabel Lozano ◽  
...  
Keyword(s):  
Heart Rate ◽  
Behavior Problems ◽  
Antisocial Behavior ◽  
Externalizing Behavior ◽  
Growth Models ◽  
Externalizing Behavior Problems ◽  
Growth Patterns ◽  
Genetic Influences ◽  
Parent Ratings ◽  
Resting Heart Rate

AbstractThe genetic and environmental basis of a well-replicated association between antisocial behavior (ASB) and resting heart rate was investigated in a longitudinal twin study, based on two measurements between the ages of 9 and 14 years. ASB was defined as a broad continuum of externalizing behavior problems, assessed at each occasion through a composite measure based on parent ratings of trait aggression, delinquent behaviors, and psychopathic traits in their children. Parent ratings of ASB significantly decreased across age from childhood to early adolescence, although latent growth models indicated significant variation and twin similarity in the growth patterns, which were explained almost entirely by genetic influences. Resting heart rate at age 9–10 years old was inversely related to levels of ASB but not change patterns of ASB across age or occasions. Biometrical analyses indicated significant genetic influences on heart rate during childhood, as well as ASB throughout development from age 9 to 14. Both level and slope variation were significantly influenced by genetic factors. Of importance, the low resting heart rate and ASB association was significantly and entirely explained by their genetic covariation, although the heritable component of heart rate explained only a small portion (1–4%) of the substantial genetic variance in ASB. Although the effect size is small, children with low resting heart rate appear to be genetically predisposed toward externalizing behavior problems as early as age 9 years old.

scholarly journals From classical to nonparametric growth models: Towards comprehensive modelling of mussel growth patterns

2017 ◽  
Vol 127 ◽  
pp. 41-48 ◽  
Author(s):  
Isabel Fuentes-Santos ◽  
Uxío Labarta ◽  
Kristina Arranz ◽  
Mª José Fernández-Reiriz
Keyword(s):  
Growth Models ◽  
Growth Patterns
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