Bone Scaffold Fabrication System Study

2007 ◽  
Author(s):  
Lin Lu ◽  
David Wootton ◽  
Peter I. Lelkes ◽  
Jack Zhou
Keyword(s):  
Tissue Engineering ◽  
Flow Rate ◽  
Intelligent System ◽  
Bone Substitutes ◽  
Water Soluble ◽  
Health Concern ◽  
Bone Scaffold ◽  
Systems And Control ◽  
Porous Biomaterials ◽  
And Control

Musculoskeletal conditions are a major health concern in United States because of a large aging population and increased occurrence of sport-related injuries. The need for bone substitutes is especially important. Traditional treatments of bone-defect have many limitations. Bone tissue engineering may offer a less painful alternative to traditional bone grafts with lower risk of infection. This research integrates biomimetic modeling, solid freedom fabrication (SFF), systems and control, and tissue engineering in one intelligent system for structured, highly porous biomaterials, which will be applied to bone scaffolds. Recently a new SFF-based fabrication system has been developed, which uses a pressurized extrusion to print highly biocompatible and water soluble sucrose bone scaffold porogens. The fabrication process for PCL scaffold implemented and tested using the newly developed porogen system. The resultant scaffold demonstrates the defined porous structure designed into the sucrose porogens. The viscosity of sucrose mixture has been tested and analyzed. The flow rate measurements of sucrose machine have been carried out. The input factor, which induced uncertainty in the flow rate of the microprinting system has been analyzed. The result showed that the reservoir pressure was dominant to determine the flow rate. This is very important for improving the quality control of our fabrication system.

Manufacturing System Development for Fabrication of Bone Scaffold

2005 ◽  
Author(s):  
Lin Lu ◽  
Robert S. Dembzynski ◽  
Mark J. Mondrinos ◽  
David Wootton ◽  
Peter I. Lelkes ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Calcium Phosphate ◽  
Rapid Prototyping ◽  
Intelligent System ◽  
System Development ◽  
Bone Substitutes ◽  
Water Soluble ◽  
Health Concern ◽  
Bone Scaffold ◽  
Bone Scaffolds

Musculoskeletal conditions are a major health concern in United States because of a large aging population and increased occurrence of sport-related injuries. The need for bone substitutes is especially important. Traditional treatments of bone-defect have many of limitations. Bone tissue engineering may offer a less painful alternative to traditional bone grafts with lower risk of infection. This research integrates biomimetic modeling, solid freeform fabrication (SFF), systems and control, and tissue engineering in one intelligent system for structured, highly porous biomaterials, which will be applied to bone scaffolds. Currently a new SFF-based fabrication system has been developed, which uses a pressurized extrusion to print highly biocompatible and water soluble sucrose bone scaffold porogens. To date, this system can build simple bone structures. In parallel we are utilizing a commercial rapid prototyping (RP) machine to fabricate thermoplastic porogens of various designs to determine the feasibility of injecting a highly viscous scaffold material into porogens. Materials which have been successfully used to make scaffolds by injection include calcium phosphate cement (CPC), molten poly-caprolactone (PCL), 90/10 and 80/20 (v/v %) composite of PCL and calcium phosphate (CaPO4,). Results presented for the injection method include characterization of attainable feature resolution of the RP machine, as well as preliminary cell-biomaterial interaction data demonstrating biocompatibility of CPC scaffolds. The preliminary results using a commercial rapid prototyping machine have demonstrated that the indirect porogen technique can improve 2–4 folds the resolution of SFF system in fabricating bone scaffolds. The resultant scaffolds demonstrate that the defined porous structures will be suitable for tissue engineering applications.

scholarly journals Experimental characterization and computational modelling of two-dimensional cell spreading for skeletal regeneration

2007 ◽  
Vol 4 (17) ◽  
pp. 1107-1117 ◽  
Author(s):  
Bram G Sengers ◽  
Colin P Please ◽  
Richard O.C Oreffo
Keyword(s):  
Computational Modelling ◽  
Theoretical Models ◽  
Cell Types ◽  
Bone Substitutes ◽  
Two Dimensional ◽  
Skeletal Tissue ◽  
Mg63 Cells ◽  
High Level ◽  
Porous Biomaterials ◽  
And Control

Limited cell ingrowth is a major problem for tissue engineering and the clinical application of porous biomaterials as bone substitutes. As a first step, migration and proliferation of an interacting cell population can be studied in two-dimensional culture. Mathematical modelling is essential to generalize the results of these experiments and to derive the intrinsic parameters that can be used for predictions. However, a more thorough evaluation of theoretical models is hampered by limited experimental observations. In this study, experiments and image analysis methods were developed to provide a detailed spatial and temporal picture of how cell distributions evolve. These methods were used to quantify the migration and proliferation of skeletal cell types including MG63 and human bone marrow stromal cells (HBMSCs). The high level of detail with which the cell distributions were mapped enabled a precise assessment of the correspondence between experimental results and theoretical model predictions. This analysis revealed that the standard Fisher equation is appropriate for describing the migration behaviour of the HBMSC population, while for the MG63 cells a sharp front model is more appropriate. In combination with experiments, this type of mathematical model will prove useful in predicting cell ingrowth and improving strategies and control of skeletal tissue regeneration.

scholarly journals Accurate Calibration in Multi-Material 3D Bioprinting for Tissue Engineering

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1402 ◽  
Author(s):  
Enrique Sodupe-Ortega ◽  
Andres Sanz-Garcia ◽  
Alpha Pernia-Espinoza ◽  
Carmen Escobedo-Lucea
Keyword(s):  
Tissue Engineering ◽  
Three Dimensional ◽  
Calibration Method ◽  
3D Bioprinting ◽  
Vascular Networks ◽  
Single Session ◽  
Systems And Control ◽  
Complex Relationships ◽  
And Control ◽  
Printing Parameters

Most of the studies in three-dimensional (3D) bioprinting have been traditionally based on printing a single bioink. Addressing the complexity of organ and tissue engineering, however, will require combining multiple building and sacrificial biomaterials and several cells types in a single biofabrication session. This is a significant challenge, and, to tackle that, we must focus on the complex relationships between the printing parameters and the print resolution. In this paper, we study the influence of the main parameters driven multi-material 3D bioprinting and we present a method to calibrate these systems and control the print resolution accurately. Firstly, poloxamer hydrogels were extruded using a desktop 3D printer modified to incorporate four microextrusion-based bioprinting (MEBB) printheads. The printed hydrogels provided us the particular range of printing parameters (mainly printing pressure, deposition speed, and nozzle z-offset) to assure the correct calibration of the multi-material 3D bioprinter. Using the printheads, we demonstrated the excellent performance of the calibrated system extruding different fluorescent bioinks. Representative multi-material structures were printed in both poloxamer and cell-laden gelatin-alginate bioinks in a single session corroborating the capabilities of our system and the calibration method. Cell viability was not significantly affected by any of the changes proposed. We conclude that our proposal has enormous potential to help with advancing in the creation of complex 3D constructs and vascular networks for tissue engineering.

Systems and control in Scotland

2001 ◽  
Vol 2001 (1) ◽  
pp. 32-34 ◽  
Author(s):  
Clive Seager
Keyword(s):  
Systems And Control ◽  
And Control

scholarly journals A Legionnaires’ Disease Cluster in a Private Building in Italy

2021 ◽  
Vol 18 (13) ◽  
pp. 6922
Author(s):  
Maria Luisa Ricci ◽  
Maria Cristina Rota ◽  
Maria Grazia Caporali ◽  
Antonietta Girolamo ◽  
Maria Scaturro
Keyword(s):  
Severe Pneumonia ◽  
Control Measures ◽  
Health Concern ◽  
Human Consumption ◽  
Domestic Water ◽  
Quality Of Water ◽  
Legionnaires Disease ◽  
Prevention And Control Measures ◽  
Private Homes ◽  
And Control

Legionnaires’ disease (LD) is a severe pneumonia caused by bacteria belonging to the genus Legionella. This is a major public health concern and infections are steadily increasing worldwide. Several sources of infection have been identified, but they have not always been linked to human isolates by molecular match. The well-known Legionella contamination of private homes has rarely been associated with the acquisition of the disease, although some patients never left their homes during the incubation period. This study demonstrated by genomic matching between clinical and environmental Legionella isolates that the source of an LD cluster was a private building. Monoclonal antibodies and sequence-based typing were used to type the isolates, and the results clearly demonstrated the molecular relationship between the strains highlighting the risk of contracting LD at home. To contain this risk, the new European directive on the quality of water intended for human consumption has introduced for the first time Legionella as a microbiological parameter to be investigated in domestic water systems. This should lead to a greater attention to prevention and control measures for domestic Legionella contamination and, consequently, to a possible reduction in community acquired LD cases.

scholarly journals Design and Research on Power Systems and Algorithms for Controlling Electric Underground Mining Machines Powered by Batteries

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4060
Author(s):  
Artur Kozłowski ◽  
Łukasz Bołoz
Keyword(s):  
Power Systems ◽  
Power Supply ◽  
Internal Combustion Engines ◽  
Underground Mining ◽  
Test Stand ◽  
Research Network ◽  
Control Algorithms ◽  
Systems And Control ◽  
And Control ◽  
Supply Systems

This article discusses the work that resulted in the development of two battery-powered self-propelled electric mining machines intended for operation in the conditions of a Polish copper ore mine. Currently, the global mining industry is seeing a growing interest in battery-powered electric machines, which are replacing solutions powered by internal combustion engines. The cooperation of Mine Master, Łukasiewicz Research Network—Institute of Innovative Technologies EMAG and AGH University of Science and Technology allowed carrying out a number of works that resulted in the production of two completely new machines. In order to develop the requirements and assumptions for the designed battery-powered propulsion systems, underground tests of the existing combustion machines were carried out. Based on the results of these tests, power supply systems and control algorithms were developed and verified in a virtual environment. Next, a laboratory test stand for validating power supply systems and control algorithms was developed and constructed. The tests were aimed at checking all possible situations in which the battery gets discharged as a result of the machine’s ride or operation and when it is charged from the mine’s mains or with energy recovered during braking. Simulations of undesirable situations, such as fluctuations in the supply voltage or charging power limitation, were also carried out at the test stand. Positive test results were obtained. Finally, the power supply systems along with control algorithms were implemented and tested in the produced battery-powered machines during operational trials. The power systems and control algorithms are universal enough to be implemented in two different types of machines. Both machines were specially designed to substitute diesel machines in the conditions of a Polish ore mine. They are the lowest underground battery-powered drilling and bolting rigs with onboard chargers. The machines can also be charged by external fast battery chargers.

scholarly journals Agro-Environmental Determinants of Leptospirosis: A Retrospective Spatiotemporal Analysis (2004−2014) in Mahasarakham Province (Thailand)

2021 ◽  
Vol 6 (3) ◽  
pp. 115
Author(s):  
Jaruwan Viroj ◽  
Julien Claude ◽  
Claire Lajaunie ◽  
Julien Cappelle ◽  
Anamika Kritiyakan ◽  
...  
Keyword(s):  
Public Health ◽  
Animal Health ◽  
Spatiotemporal Analysis ◽  
Health Concern ◽  
Intersectoral Collaboration ◽  
The Public ◽  
Additive Modeling ◽  
The One ◽  
And Control ◽  
Northeastern Thailand

Leptospirosis has been recognized as a major public health concern in Thailand following dramatic outbreaks. We analyzed human leptospirosis incidence between 2004 and 2014 in Mahasarakham province, Northeastern Thailand, in order to identify the agronomical and environmental factors likely to explain incidence at the level of 133 sub-districts and 1,982 villages of the province. We performed general additive modeling (GAM) in order to take the spatial-temporal epidemiological dynamics into account. The results of GAM analyses showed that the average slope, population size, pig density, cow density and flood cover were significantly associated with leptospirosis occurrence in a district. Our results stress the importance of livestock favoring leptospirosis transmission to humans and suggest that prevention and control of leptospirosis need strong intersectoral collaboration between the public health, the livestock department and local communities. More specifically, such collaboration should integrate leptospirosis surveillance in both public and animal health for a better control of diseases in livestock while promoting public health prevention as encouraged by the One Health approach.

scholarly journals An Introduction to Development of Centralized and Distributed Stochastic Approximation Algorithm with Expanding Truncations

Algorithms ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 174
Author(s):  
Wenxiao Zhao
Keyword(s):  
Approximation Algorithm ◽  
Stochastic Approximation ◽  
Probabilistic Method ◽  
Principal Component ◽  
Stochastic Approximation Algorithm ◽  
The Past ◽  
Systems And Control ◽  
Ode Method ◽  
Centralized Algorithm ◽  
And Control

The stochastic approximation algorithm (SAA), starting from the pioneer work by Robbins and Monro in 1950s, has been successfully applied in systems and control, statistics, machine learning, and so forth. In this paper, we will review the development of SAA in China, to be specific, the stochastic approximation algorithm with expanding truncations (SAAWET) developed by Han-Fu Chen and his colleagues during the past 35 years. We first review the historical development for the centralized algorithm including the probabilistic method (PM) and the ordinary differential equation (ODE) method for SAA and the trajectory-subsequence method for SAAWET. Then, we will give an application example of SAAWET to the recursive principal component analysis. We will also introduce the recent progress on SAAWET in a networked and distributed setting, named the distributed SAAWET (DSAAWET).

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