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Article
Publication date: 19 July 2019

Linlin Wang, Jianyao Yao, Huiming Ning, Liangke Wu, Dongyang Sun and Ning Hu

This paper aims to investigate the effects of the pia matter on cerebral cortical folding.

Abstract

Purpose

This paper aims to investigate the effects of the pia matter on cerebral cortical folding.

Design/methodology/approach

A three-layer buckling simulation model composited by the white matter, gray matter and the pia matter is adopted to analyze the effect of the pia matter on cortical folding. The volume growth of brain tissues is simulated using thermal expansion. The effects of the pia matter growth rate, thickness and stiffness on cortical folding is investigated.

Findings

The simulation results show that all of these three aforementioned factors of pia matter have obvious effects on cerebral cortical folding. Especially, the thickening of the pia matter may lead to cortical folding malformation such as polymicrogyria, which is in good agreement with the recent reported anatomical findings.

Originality/value

The three-layer model in this paper composited by the white matter, gray matter and the pia matter is different from the usually used two-layer model only composited by the white matter and gray matter. This three-layer model has successfully validated the effect of the pia matter on cerebral cortical folding. The simulation results can explain the anatomical findings very well.

Details

Engineering Computations, vol. 36 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 19 April 2022

Raj Agarwal, Vishal Gupta and Jaskaran Singh

The complications caused by metallic orthopaedic bone screws like stress-shielding effect, screw loosening, screw migration, higher density difference, painful reoperation and…

Abstract

Purpose

The complications caused by metallic orthopaedic bone screws like stress-shielding effect, screw loosening, screw migration, higher density difference, painful reoperation and revision surgery for screw extraction can be overcome with the bioabsorbable bone screws. This study aims to use additive manufacturing (AM) technology to fabricate orthopaedic biodegradable cortical screws to reduce the bone-screw-related-complications.

Design/methodology/approach

The fused filament fabrication technology (FFFT)-based AM technique is used to fabricate orthopaedic cortical screws. The influence of various process parameters like infill pattern, infill percentage, layer height, wall thickness and different biological solutions were observed on the compressive strength and degradation behaviour of cortical screws.

Findings

The porous lattice structures in cortical screws using the rapid prototyping technique were found to be better as porous screws can enhance bone growth and accelerate the osseointegration process with sufficient mechanical strength. The compressive strength and degradation rate of the screw is highly dependent on process parameters used during the fabrication of the screw. The compressive strength of screw is inversely proportional to the degradation rate of the cortical screw.

Research limitations/implications

The present study is focused on cortical screws. Further different orthopaedic screws can be modified with the use of different rapid prototyping techniques.

Originality/value

The use of rapid prototyping techniques for patient-specific bone screw designs is scantly reported. This study uses FFFT-based AM technique to fabricate various infill patterns and porosity of cortical screws to enhance the design of orthopaedic cortical screws.

Details

Rapid Prototyping Journal, vol. 28 no. 9
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 August 2005

Huimin Wang and Xungai Wang

Wool fibres consist of micro to nano scale protein constituents that could be used for innovative applications. While techniques for extracting these constituents or making wool…

Abstract

Wool fibres consist of micro to nano scale protein constituents that could be used for innovative applications. While techniques for extracting these constituents or making wool fibres into organic powders have been developed, effectively dispersing the particles and accurately determining their size has been difficult in practice. In this study, an ultrasonic method was employed to disperse cortical cells extracted from wool fibres into an immersion oil or ethanol. Specimens of the cortical cells were then observed under optical microscopy and scanning electron microscopy, respectively. Cell length and maximum cell diameter were measured to quantify the cell size. The results suggest significant discrepancies exist in the cortical cell size obtained from the two different measurement techniques. The maximum diameter of wool cortical cells obtained from the optical microscope was much larger than that from the scanning electron microscope, while the length was much shorter. A correction factor is given so that cortical cell size obtained from the two measurement techniques can be compared.

Details

Research Journal of Textile and Apparel, vol. 9 no. 3
Type: Research Article
ISSN: 1560-6074

Keywords

Book part
Publication date: 21 November 2016

Douglas Jozef Angus and Eddie Harmon-Jones

Extensive human and animal research has examined approach and withdrawal motivation, which we define as the simple urge to move toward or away, respectively. In this chapter, we…

Abstract

Extensive human and animal research has examined approach and withdrawal motivation, which we define as the simple urge to move toward or away, respectively. In this chapter, we review seminal and recent research that showing that asymmetrical frontal cortical activity underlies approach and withdrawal motivation that occur during childhood, that characterize certain psychopathologies, and are present in everyday emotional experiences. Specifically, greater left-frontal activity is involved in approach motivation, including the expression and experience of anger, jealousy, desire, and joy. Conversely, greater right-frontal activity is involved in withdrawal motivation, including the expression and experience of some forms of sadness, crying, and depressed mood. We also review recent research suggesting that connectivity between the frontal and parietal cortices is a potential mechanism for the motivation-related effects of asymmetrical frontal activity.

Details

Recent Developments in Neuroscience Research on Human Motivation
Type: Book
ISBN: 978-1-78635-474-7

Keywords

Article
Publication date: 14 January 2014

Timothy J. Horn, Ola L.A. Harrysson, Harvey A. West II, Jeffrey P. Little and Denis J. Marcellin-Little

The aim of this study is to describe an improved experimental substrate for the mechanical testing of patient-specific implants fabricated using direct metal additive…

Abstract

Purpose

The aim of this study is to describe an improved experimental substrate for the mechanical testing of patient-specific implants fabricated using direct metal additive manufacturing processes. This method reduces variability and sample size requirements and addresses the importance of geometry at the bone/implant interface.

Design/methodology/approach

Short-fiber glass/resin materials for cortical bone and polyurethane foam materials for cancellous bone were evaluated using standard tensile coupons. A method for fabricating bone analogs with patient-specific geometries using rapid tooling is presented. Bone analogs of a canine radius were fabricated and compared to cadaveric specimens in several biomechanical tests as validation.

Findings

The analog materials exhibit a tensile modulus that falls within the range of expected values for cortical and cancellous bone. The tensile properties of the cortical bone analog vary with fiber loading. The canine radius models exhibited similar mechanical properties to the cadaveric specimens with a reduced variability.

Research limitations/implications

Additional replications involving different bone geometries, types of bone and/or implants are required for a full validation. Further, the materials used here are only intended to mimic the mechanical properties of bone on a macro scale within a relatively narrow range. These analog models have not been shown to address the complex microscopic or viscoelastic behavior of bone in the present study.

Originality/value

Scientific data on the formulation and fabrication of bone analogs are absent from the literature. The literature also lacks an experimental platform that matches patient-specific implant/bone geometries at the bone implant interface.

Details

Rapid Prototyping Journal, vol. 20 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 8 June 2015

F.G.A. Silva, M.F.S.F. de Moura, N Dourado, F. A. M. Pereira, J.J.L. Morais, M. I. R. Dias, Paulo J. Lourenço and Fernando M. Judas

Fracture characterization of human cortical bone under pure mode I loading was performed in this work. The purpose of this paper is to validate the proposed test and procedure…

Abstract

Purpose

Fracture characterization of human cortical bone under pure mode I loading was performed in this work. The purpose of this paper is to validate the proposed test and procedure concerning fracture characterization of human cortical bone under pure mode I loading.

Design/methodology/approach

A miniaturized version of the double cantilever beam (DCB) test was used for the experimental tests. A data reduction scheme based on crack equivalent concept and Timoshenko beam theory is proposed to overcome difficulties inherent to crack length monitoring during the test. The application of the method propitiates an easy determination of the Resistance-curves (R-curves) that allow to define the fracture energy under mode I loading from the plateau region. The average value of fracture energy was subsequently used in a numerical analysis with element method involving cohesive zone modelling.

Findings

The excellent agreement obtained reveals that the proposed test and associated methodology is quite effective concerning fracture characterization of human cortical bone under pure mode I loading.

Originality/value

A miniaturized version of traditional DCB test was proposed for cortical human bone fracture characterization under mode I loading owing to size restrictions imposed by human femur. In fact, DCB specimen propitiates a longer length for self-similar crack propagation without undertaking spurious effects. As a consequence, a R-curve was obtained allowing an adequate characterization of cortical bone fracture under mode I loading.

Details

International Journal of Structural Integrity, vol. 6 no. 3
Type: Research Article
ISSN: 1757-9864

Keywords

Open Access
Article
Publication date: 4 March 2014

Andrei Novac and Robert G. Bota

How does the human brain absorb information and turn it into skills of its own in psychotherapy? In an attempt to answer this question, the authors will review the intricacies of…

Abstract

How does the human brain absorb information and turn it into skills of its own in psychotherapy? In an attempt to answer this question, the authors will review the intricacies of processing channels in psychotherapy and propose the term transprocessing (as in transduction and processing combined) for the underlying mechanisms. Through transprocessing the brain processes multimodal memories and creates reparative solutions in the course of psychotherapy. Transprocessing is proposed as a stage-sequenced mechanism of deconstruction of engrained patterns of response. Through psychotherapy, emotional-cognitive reintegration and its consolidation is accomplished. This process is mediated by cellular and neural plasticity changes.

Article
Publication date: 3 April 2017

Kip Errett Patterson

The purpose of this paper is to present a theory that applies Miller et al.’s (1960) Test-Operate-Test-Exit (TOTE) concept to the psychophysiology involved in…

Abstract

Purpose

The purpose of this paper is to present a theory that applies Miller et al.’s (1960) Test-Operate-Test-Exit (TOTE) concept to the psychophysiology involved in electroencephalographic (EEG) biofeedback (BFB).

Design/methodology/approach

Six components are presented, namely, the teleological brain, attractors as the “test” in TOTEs, EEG production, positive and negative feedback, synaptogenesis and designated actor, and then integrated into a theoretical structure. Comparisons with the previous conceptualizations are discussed, and finally, suggestions for practical application and needed research are offered.

Findings

Previous theories neglected significant variables and promoted unverified conceptualizations. These issues are redressed with a psychophysiological, cybernetic theory.

Research limitations/implications

The pursuit of substantive research needed to verify the theory would improve the scientific foundations for EEG BFB.

Practical implications

This theory shifts the designated actor in BFB to the participant’s brain, away from the BFB provider. EEG BFB is thus viewed as a means for neuronominalization driven by the brain’s attractor systems instead of as an intrusive intervention.

Social implications

The theory proposes a much more participant-centric process than previous modes, which also promotes self-determination. The research validation needed for the theory could produce wider EEG BFB acceptance and application.

Originality/value

The theory is a complete departure from previous conceptualizations. It is the first instance of TOTE application to psychophysiological processes, and it is the first fully cybernetic conceptualization of EEG BFB.

Details

Kybernetes, vol. 46 no. 4
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 30 March 2010

Byron Olson and Jennie Si

Using cortical neurons of animals to control external devices allows experimenters a unique opportunity to study the capability of the brain to utilize a new actuator. The purpose…

Abstract

Purpose

Using cortical neurons of animals to control external devices allows experimenters a unique opportunity to study the capability of the brain to utilize a new actuator. The purpose of this paper is to investigate the ability of unrestrained rats to control a directional task using motor cortical signals.

Design/methodology/approach

In freely moving rats, signals recorded from the motor cortex of the brain enabled the use of a closed loop brain machine interface (BMI) system to replace paddle pressing for a directional task. In this system, ring rates from several (two to ten) motor cortical neurons at several consecutive time points were used as input to a support vector machine (SVM) classifier. The decision‐function value obtained from the SVM was then used to determine which relay should be activated to produce paddle‐pressing signals in the task. All five animals tested were able to use this interface immediately and significant changes in neural activity arise in a single, 45‐min, experimental session. Neural data from three of the subjects were examined for changes from the calibration phase (data used to build the SVM model) to the late cortically controlled phase.

Findings

Detailed analysis shows that neural activity changes significantly from the calibration phase to the cortically controlled phase, furthermore, the decision‐function values arising from these neural signals change to support better performance. By examining which neurons and times are selected by the SVM to have significant impact on the decision‐function value as well as which of these elements change significantly, a mechanism of adaptation begins to emerge in which the SVM properly assigns high importance to dimensions that easily predict the desired output, however, under closed‐loop control, the animal selects a small number of neurons (at most or all times) and chooses to make the firing rates more distinguishable. Video taken of one of the subjects further suggests the nature of the behavioral correlates of these changes.

Practical implications

In the design of practical BMI devices for human patients, one effective strategy might involve creating mappings from multi‐neuron ensembles using state‐of‐the‐art machine learning techniques, but expect that the patients who use the devices will adapt to the devices using single neuron modulation changes.

Originality/value

In the design of practical BMI devices for human patients, one effective strategy might involve creating mappings from multi‐neuron ensembles using state‐of‐the‐art machine learning techniques, but expect that the patients who use the devices will adapt to the devices using single neuron modulation changes. The proposed decentralization approach is interesting for the design of optimization algorithms that can run on computing systems that use principles of self‐organization and have no central control.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 3 no. 1
Type: Research Article
ISSN: 1756-378X

Keywords

Article
Publication date: 6 August 2019

Sahil Dhiman, Sarabjeet Singh Sidhu, Preetkanwal Singh Bains and Marjan Bahraminasab

With technology advances, metallic implants claim to improve the quality and durability of human life. In the recent decade, Ti-6Al-4V biomaterial has been additively manufactured…

Abstract

Purpose

With technology advances, metallic implants claim to improve the quality and durability of human life. In the recent decade, Ti-6Al-4V biomaterial has been additively manufactured via selective laser melting (SLM) for orthopedic applications. This paper aims to provide state-of-the-art on mechanobiology of these fabricated components.

Design/methodology/approach

A literature review has been done to explore the potential of SLM fabricated Ti-6Al-4V porous lattice structures (LS) as bone substitutes. The emphasize was on the effect of process parameters and porosity on mechanical and biological properties. The papers published since 2007 were considered here. The keywords used to search were porous Ti-6Al-4V, additive manufacturing, metal three-dimensional printing, osseointegration, porous LS, SLM, in vitro and in vivo.

Findings

The properties of SLM porous biomaterials were compared with different human bones, and bulk SLM fabricated Ti-6Al-4V structures. The comparison was also made between LS with different unit cells to find out whether there is any particular design that can mimic the human bone functionality and enhance osseointegration.

Originality/value

The implant porosity plays a crucial role in mechanical and biological characteristics that relies on the optimum controlled process variables and design attributes. It was also indicated that although the mechanical strength (compressive and fatigue) of porous LS is not mostly close to natural cortical bone, elastic modulus can be adjusted to match that of cortical or cancellous bone. Porous Ti-6Al-4V provide favorable bone formation. However, the effect of design variables on biological behavior cannot be fully conclusive as few studies have been dedicated to this.

Details

Rapid Prototyping Journal, vol. 25 no. 7
Type: Research Article
ISSN: 1355-2546

Keywords

1 – 10 of 775