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1
Joshi, Abhijeet Bhaskar. "Mechanical behavior of the human lumbar intervertebral disc with polymeric hydrogel nucleus implant : an experimental and finite element study /." Philadelphia, Pa. : Drexel University, 2004. http://dspace.library.drexel.edu/handle/1860/272.
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Frost, Brody. "Polymer Composite Spinal Disc Implants." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/78783.
Full textAbstract:
The goal of this research study was to create an artificial annulus fibrosus similar to that of the natural intervertebral disc, as well as find preliminary results for vertebral endplate connection and nucleus pulposus internal pressure, for the correction of disc degeneration in the spine. The three-part composite samples needed to demonstrate good shock absorption and load distribution while maintaining strength and flexibility, and removing the need for metal in the body, something of which no current total disc replacement or spinal fusion surgery can offer. For this study, the spinal disc was separated into its three different components, the annulus fibrosus, the nucleus pulposus, and the vertebral endplates, each playing a vital role in the function of the disc. Two low-cost materials were selected, a Covestro polyurethane and cellulose nanocrystals, for the purpose of creating a polymer composite spinal disc implant. A methodology was established for creating the cast composite material for use as an annulus fibrosus, while also investigating its mechanical properties. The same composite material was used to acquire preliminary results for vertebral endplate connection to the synthesized annulus, however no additional material was used to determine or mimic the mechanical properties of these endplates, due to time constraints. Also because of time constraints, the nucleus used in this study was only comprised of water with no other additives for preliminary testing since the natural nucleus is comprised of about 80-90% water. These properties were then compared to the mechanical properties of the natural disc, so that they could be finely tuned to emulate the natural disc. It is shown in this study that the composite material, when swelled in water, was able to mimic the annulus fibrosus in tensile strength and modulus, however showed higher compressive strength and modulus than ideal. The samples also did not undergo any permanent deformation within the realm of force actually introduced to the natural disc. The vertebral endplates showed decent adhesion to the synthesized annulus, however there were slight defects that became failure concentrators during compression testing. The nucleus showed promising results maintaining good internal pressure to the system causing better compressive load distribution, with barreling of the samples.<br>Master of Science<br>Spinal disc degeneration is a very prevalent problem in today’s society, effecting anywhere from 12% to 35% of a given population. It usually occurs in the lumbar section of the spine, and when severe enough, can cause bulging and herniation of the intervertebral disc itself. This can cause immense lower back pain in individual’s stricken with this disease, and in the US, medical costs associated with lower back pain to exceed $100 billion. Current solutions to this problem include multiple different treatment options of which, spinal fusion surgery and total disc replacement (TDR) are among the most common. Although these treatments cause pain relief for the majority of patients, there are multiple challenges that come with these options. For example, spinal fusion surgery severely limits the mobility of its patients by fusing two vertebrae together, disallowing any individual movement, and TDR can cause hypermobility in among the vertebrae and offer little to no shock absorption of loads. Therefore, a better treatment option is needed to relieve the pain of the patients, as well as maintain equal motion, shock absorption, and load cushioning to that of the normal intervertebral disc and remaining biocompatible. The goal of this research study was to create a three-component system, like that of the natural intervertebral disc, for the use of spinal disc replacement and to replace current options. The fabricated system was comprised of the three components found in the natural intervertebral disc; the annulus fibrosus, the nucleus pulposus, and the vertebral endplates. Because the system will need to go in-body, the materials used were all characterized as biocompatible materials; the polyurethane currently being used in medical devices and implants, and the cellulose nanocrystals (CNCs) coming from natural cellulose in sources such as wood and plants. The results determined that the mechanical properties of the system can be fine-tuned in order to mimic the natural strength and cushioning capabilities of the natural disc, based on CNC content added to the polyurethane, and when all three components of the system are added together, the compressive stress-strain is most similar to the natural disc in compression. However, the system did show failure in the connection between the annulus fibrosus and vertebral endplates, causing herniation of the nucleus similar to the initial problem attempting to be solved. For this, more ideal fabrication methods should be researched in the future including 3D printing techniques, injection molding, and roll milling. As well as alternate fabrication techniques, cell grow and viability should be determined to show that cells don’t die once the system in implanted.
3
Frost, Brody A. "Polymer Composite Spinal Disc Implants." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78783.
Full textAbstract:
The goal of this research study was to create an artificial annulus fibrosus similar to that of the natural intervertebral disc, as well as find preliminary results for vertebral endplate connection and nucleus pulposus internal pressure, for the correction of disc degeneration in the spine. The three-part composite samples needed to demonstrate good shock absorption and load distribution while maintaining strength and flexibility, and removing the need for metal in the body, something of which no current total disc replacement or spinal fusion surgery can offer. For this study, the spinal disc was separated into its three different components, the annulus fibrosus, the nucleus pulposus, and the vertebral endplates, each playing a vital role in the function of the disc. Two low-cost materials were selected, a Covestro polyurethane and cellulose nanocrystals, for the purpose of creating a polymer composite spinal disc implant. A methodology was established for creating the cast composite material for use as an annulus fibrosus, while also investigating its mechanical properties. The same composite material was used to acquire preliminary results for vertebral endplate connection to the synthesized annulus, however no additional material was used to determine or mimic the mechanical properties of these endplates, due to time constraints. Also because of time constraints, the nucleus used in this study was only comprised of water with no other additives for preliminary testing since the natural nucleus is comprised of about 80-90% water. These properties were then compared to the mechanical properties of the natural disc, so that they could be finely tuned to emulate the natural disc. It is shown in this study that the composite material, when swelled in water, was able to mimic the annulus fibrosus in tensile strength and modulus, however showed higher compressive strength and modulus than ideal. The samples also did not undergo any permanent deformation within the realm of force actually introduced to the natural disc. The vertebral endplates showed decent adhesion to the synthesized annulus, however there were slight defects that became failure concentrators during compression testing. The nucleus showed promising results maintaining good internal pressure to the system causing better compressive load distribution, with barreling of the samples.<br>Master of Science<br>Spinal disc degeneration is a very prevalent problem in today’s society, effecting anywhere from 12% to 35% of a given population. It usually occurs in the lumbar section of the spine, and when severe enough, can cause bulging and herniation of the intervertebral disc itself. This can cause immense lower back pain in individual’s stricken with this disease, and in the US, medical costs associated with lower back pain to exceed $100 billion. Current solutions to this problem include multiple different treatment options of which, spinal fusion surgery and total disc replacement (TDR) are among the most common. Although these treatments cause pain relief for the majority of patients, there are multiple challenges that come with these options. For example, spinal fusion surgery severely limits the mobility of its patients by fusing two vertebrae together, disallowing any individual movement, and TDR can cause hypermobility in among the vertebrae and offer little to no shock absorption of loads. Therefore, a better treatment option is needed to relieve the pain of the patients, as well as maintain equal motion, shock absorption, and load cushioning to that of the normal intervertebral disc and remaining biocompatible. The goal of this research study was to create a three-component system, like that of the natural intervertebral disc, for the use of spinal disc replacement and to replace current options. The fabricated system was comprised of the three components found in the natural intervertebral disc; the annulus fibrosus, the nucleus pulposus, and the vertebral endplates. Because the system will need to go in-body, the materials used were all characterized as biocompatible materials; the polyurethane currently being used in medical devices and implants, and the cellulose nanocrystals (CNCs) coming from natural cellulose in sources such as wood and plants. The results determined that the mechanical properties of the system can be fine-tuned in order to mimic the natural strength and cushioning capabilities of the natural disc, based on CNC content added to the polyurethane, and when all three components of the system are added together, the compressive stress-strain is most similar to the natural disc in compression. However, the system did show failure in the connection between the annulus fibrosus and vertebral endplates, causing herniation of the nucleus similar to the initial problem attempting to be solved. For this, more ideal fabrication methods should be researched in the future including 3D printing techniques, injection molding, and roll milling. As well as alternate fabrication techniques, cell grow and viability should be determined to show that cells don’t die once the system in implanted.
4
Dodgen, Eric Ray. "Spinal Implant with Customized and Non-Linear Stiffness." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2699.
Full textAbstract:
There is a need for spinal implants that have nonlinear stiffness to provide stabilization if the spine loses stiffness through injury, degeneration, or surgery. There is also a need for spinal implants to be customizable for individual needs, and to be small enough to be unobtrusive once implanted. Past and ongoing work that defines the effects of degeneration on the torque rotation curve of a functional spinal unit (FSU) were used to produce a spinal implant which could meet these requirements. This thesis proposes contact-aided inserts to be used with the FlexSuRe™ spinal implant to create a nonlinear stiffness. Moreover, different inserts can be used to create customized behaviors. An analytical model is introduced for insert design, and the model is verified using a finite element model and tests of physical prototypes both on a tensile tester and cadaveric testing on an in-house spine tester. Testing showed the inserts are capable of creating a non-linear force-deflection curve and it was observed that the device provided increased stiffness to a spinal segment in flexion-extension and lateral-bending. This thesis further proposes that the FlexSuRe™ spinal implant can be reduced in size by joining LET joint geometries in series in a serpentine nature. An optimization procedure was performed on the new geometry and feasible designs were identified. Moreover, due to maintaining LET joint geometry, the contact-aided insert could be implemented in conjunction with this new device geometry.
5
Naylor, Jason Richard. "Biomechanical evaluation of CAdisc-L total disc replacement implant." Thesis, University of Nottingham, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.587835.
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Degenerative disc disease (DDD) is a natural degenerative process that affects the intervertebral discs of the spine and is a major cause of lower back pain. After failure of conservative measures DDD may be treated surgically by fusion or Total Disc Replacement (TOR). Fusion results in loss of motion at the operated level, causing increased motion at adjacent levels. This is thought to accelerate further degenerative changes. The intention of TOR is to replace the disc and maintain normal motion in the spine. CAdisc-L is a novel TOR implant; it preserves motion by deforming under load rather than articulating like existing devices. The objective of the study was to ascertain the effect of implantation of CAdisc-L on sagittal biomechanics. Spine specimens were tested before and after implantation to asses implant stiffness, range of motion and stability. Additionally the position and migration of the Instantaneous Axis of Rotation (IAR) of the specimens was recorded. Finally, the ultimate failure load of implanted specimens in compression was evaluated. Monosegmental cadaveric spine specimens were used for the study. Loads and moments were applied by a uni-axial test machine and movement of the specimen was captured using reflective markers and a motion tracking camera. Implantation resulted in a reduction in compressive stiffness, but an increase in overall disc height which maintained the intervertebral space in compression up to 4.4kN. A reduction in flexural stiffness was seen after implantation as well as a reduction in neutral zone. Tracking of the IAR of the specimen indicated that it migrated by a similar range to intact specimens both horizontally and vertically. The position of the IAR was displaced posteriorly my 5.2mm at 6° of flexion compared to intact specimens. Ultimate failure loads were not found to be affected significantly.
6
Hudgins, Robert Garryl. "Development and characterization of a prosthetic intervertebral disc." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/20675.
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7
Thomas, Jonathan D. Lowman Anthony M. Marcolongo Michele S. "Development of injectable hydrogels for nucleus pulposus replacement /." Philadelphia, Pa. : Drexel University, 2006. http://hdl.handle.net/1860/1228.
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8
McMillan, Iain A. "Development of an intervertebral disc implant, biomodelling methodology and a femoral endoprosthesis." Thesis, University of Canterbury. Mechanical Engineering, 2004. http://hdl.handle.net/10092/6537.
Full textAbstract:
The intervertebral discs of the lumbar spine can be damaged as a result of trauma, disease or deformity. If an intervertebral disc becomes too compromised the current surgical solution is to fuse the vertebra at the affected spinal level. Spinal fusion presents its own complications which can limit its short and long term success. One of the key limiting factors is the loss of mobility at the affected level, this causes additional loading and accelerated degradation of the adjacent intervertebral discs. Therefore, the aim of this project was to develop an intervertebral disc implant which allowed natural motion at the affected level.
The implant developed consists of a fluid filled welded bellows assembly. This arrangement is similar to a healthy intervertebral disc in which the fluid nucleus pulpous is contained by the annulus fibrosus. The proposed implant also incorporates overload and motion-restricting features to prevent the implant and spinal column being damaged.
Artificial disc implants have been developed by other researchers. The implant developed in this project is unique as it does not generate any wear debris. This is significant as wear debris can cause a macrophage response and osteolysis, thus ultimately limiting the long term viability of implants which do produce wear debris.
This thesis also details the development of BioModelling methodology for producing graphical reconstructions from medical scan data. These reconstructions can be used to produce plastic and metallic models for pre-operative planning purposes and implants for in-vivo use. While originally intended for the spinal implant work, it was ultimately used for other tasks. A case study illustrates its use in producing a maxilla implant.
The final component of this project was to design and produce a femoral endoprosthesis for a patient with Osteogenesis Imperfecta. The patient's existing implants had failed and as a result an implant was required which could fully support all the applied loads whilst still allowing the patient's healthy hip and knee joints to be retained.
9
Wood, Caura L. "(Dis)abling paradigms, cochlear implants and contested identities." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq28689.pdf.
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10
De, Beer N., and A. I. Odendaal. "The geometrical accuracy of a custom artificial intervertebral disc implant manufactured using Computed Tomography and Direct Metal Laser Sintering." Journal for New Generation Sciences, Vol 10, Issue 3: Central University of Technology, Free State, Bloemfontein, 2012. http://hdl.handle.net/11462/613.
Full textAbstract:
Published Article<br>Rapid Manufacturing (RM) has emerged over the past few years as a potential technology to successfully produce patient-specific implants for maxilla/facial and cranial reconstructive surgeries. However, in the area of spinal implants, customization has not yet come to the forefront and with growing capabilities in both software and manufacturing technologies, these opportunities need to be investigated and developed wherever possible.
The possibility of using Computed Tomography (CT) and Rapid Manufacturing (RM) technologies to design and manufacture a customized, patient-specific intervertebral implant, is investigated. Customized implants could aid in the efforts to reduce the risk of implant subsidence, which is a concern with existing standard implants. This article investigates how accurately the geometry of a customized artificial intervertebral disc (CAID) can represent the inverse geometry of a patient's vertebral endplates. The results indicate that the endplates of a customized disc implant can be manufactured to a calculated average error of 0.01mm within a confidence interval of 0.022mm, with 95% confidence, when using Direct Metal Laser Sintering.
11
Kulkarni, Nikhil S. "Effects of Implant Design Parameters on Cervical Disc Arthroplasty Performance and Sagittal Balance - A Finite Element Investigation." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1279327225.
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Prášilová, Eva. "Deformační a napěťová analýza vybraného páteřního fixátoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231429.
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The degenerative and traumatic injuries of a spine are very frequent. In those cases it is necessary to stabilize the corresponding spine segment using a spine implant. The spinal implants are rigid or flexible, the latter known as dynamic ones in medical practice. In this thesis, the problems of the physiological spinal segment and the segment with implant were solved using the computational modelling (finite element method). Computational model consists of 4 lumbar vertebrae L2 – L5, intervertebral discs, joints and spinal implants. The spinal segment was loaded by the force 400N and 200N, than by force 200N together with bending moments 2,5Nm and 5Nm depending of the motion. The displacement of the whole system, contact pressure of cartilages, equivalent strain in cancellous bone and equivalent stress in the implant were analyzed. The deformation of the physiological model and the model with the implant are comparable, but the bone tissue of the model with the implant is dramatically more loaded in vicinity of the screws.
13
Chokhandre, Snehal K. "A Biomechanical Comparison Between a Biological Intervertebral Disc and Synthetic Intervertebral Disc Implants Under Complex Loading: An In Vitro Study." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1187022568.
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Brendel, Christopher M. "Biocompatibility of Polymer Implants for Medical Applications." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1246892895.
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Dick, Christian [Verfasser], Rüdiger [Akademischer Betreuer] Westermann, and Markus [Akademischer Betreuer] Gross. "Computational Steering for Implant Planning in Orthopedics / Christian Dick. Gutachter: Markus Gross. Betreuer: Rüdiger Westermann." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1020273615/34.
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16
Arcand, Benjamin Y. "An active surgical positioning device for a cochlear implant electrode array /." Available online. Click here, 2005. http://sunshine.lib.mtu.edu/ETD/DISS/arcandb/diss.pdf.
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Vig, Slenters Tünde. "Novel silver containing antimicrobial coatings for implant materials : new applications of Ag(I) coordination networks /." [S.l.] : [s.n.], 2009. http://edoc.unibas.ch/diss/DissB_8859.
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Marcantonio, Graziano. "Development of framework for the manufacture of customized titanium cervical cage implants using additive manufacturing." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86243.
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Thesis (MEng)--Stellenbosch University, 2014.<br>ENGLISH ABSTRACT: Neck pain is a common phenomenon that occurs in a large percentage of the
population every day. While many occurrences are not deemed critical such
as those from muscle strain which can be treated with rest and pain medication,
others due to sports injuries, whiplash from car accidents, bad posture or
degeneration of the intervertebral disc can be quite severe. In extreme cases
failure of the vertebra(e) or the intervertebral disc requires surgery and possibly
the use of cervical implants.
Where intervertebral discs fail due to herniation or Degenerative Disc Disease
(DDD), Anterior Cervical Discectomy and Fusion (ACDF) is a common surgical
method used to remove the a ected disc and replace it with a cervical
cage implant. These implants are designed to restore the height between the
vertebrae, allowing bone from both vertebrae to grow through them and mineralise.
Additive Manufacturing (AM) technologies can produce parts with
complex geometries not possible using conventional manufacturing methods.
This design freedom, coupled with CT scans of a patient, allow for tailoring an
implant to the speci c anatomy of the a ected vertebrae using CAD software.
Such an approach must be regulated and shown to be technically and commercially
feasible before it can be implemented in industry. This study sought to
develop a framework for manufacturing customized cervical cage implants using
additive manufacturing. The e cacy of customization to reduce the risk of
subsidence was investigated by means of non-destructive and destructive mechanical
testing on six cadaver specimens, using readily available PEEK cage
implants as a benchmark. The results showed that the customized implant was
comparable to the PEEK, with no statistically signi cant di erence between
the two. In extreme cases, where PEEK implants cannot be used, customized
implants could be a suitable alternative to reduce the risk of subsidence.
A manufacturing cost analysis was conducted to determine economic feasibility.
The estimated cost and selling price of the customized implants under
various utilization scenarios and mark-ups was compared to readily available
PEEK implants. The estimated selling prices of the customized implants compared
favourably to the PEEK verifying the economic viability of using AM.<br>AFRIKAANSE OPSOMMING: Nek pyn is 'n algemene verskynsel wat daagliks na tevore kom in die bevolking.
Baie gevalle word nie as krities geklasi seer nie soos byvoorbeeld spier
pyn wat behandel kan word deur genoegsame rus en pyn medikasie. Pyn wat
deur sportbeserings, sweepslag beserings 'whiplash' tydens motor ongelukke,
verkeerde postuur, of deur slytasie van 'n intervertebrale skyf veroorsaak is,
word dikwels as ernstig geklasi seer. In ekstreme gevalle waar die werwel(s) of
die inervertebrale skyf(we) faal, sal chirurgie en servikale inplantate moontlik
nodig wees.
Waneer intervertebrale skywe faal weens herniatie of Degeneratiewe Skyf Siekte
(DDD) kan 'n algemene chirurgiese metode, Anterieure Servikale Discectomie
en Fusie (ACDF), gebruik word om die gea ekteerde skyf te verwyder en dit
te vervang met 'n servikale samesmelting implantaat. Hierdie implantate herstel
die hoogte tussen rugwerwels en is ontwerp sodat die been deur dit kan
groei en mineraliseer. Komplekse geometrieë kan vervaardig word deur toevoegingsvervaardiging
(AM) tegnologieë. Die ontwerp vryheid, gepaard met
CT-skanderings en CAD-sagteware stel mens in staat om die geometrie van
die implantaat aan te pas tot die spese eke anatomie van die gea ekteerde
vertebra.
So 'n benadering moet gereguleer word en eers tegnies en kommersieel uitvoerbaar
bewys word voordat dit in die bedryf geïmplementeer kan word. Hierdie
studie poog verder om 'n raamwerk vir die vervaardiging van persoonlike
servikale implantate deur middel van toevoegingsvervaardiging te ontwikkel.
Die doeltre endheid van persoonlike implantate om te verhoed dat die chirurg
die eind-plaat beskadig, en sodoende die risiko van insakking te verminder, is
ondersoek deur middel van meganiese toetse op ses kadawer monsters. Hierdie
toetse is gedoen met behulp van geredelik beskikbaar PEEK servikale implantate
as 'n maatstaf.
Die resultate het getoon dat die persoonlike- en PEEK implantate vergelykbaar
is. In moontlike gevalle waar PEEK implantate nie geskik sou wees nie,
kan persoonlike implantate 'n alternatiewe opsie wees om die risiko van insakking
te verminder.
19
De, Jongh Cornel. "Critical evaluation of predictive modelling of a cervical disc design." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/601.
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Baker, Carrie E. "Auxetic Spinal Implants: Consideration of Negative Poisson's Ratio in the Design of an Artificial Intervertebral Disc." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302099679.
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Smith, Kathryn Elizabeth. "Tailoring the toughness and biological response of photopolymerizable networks for orthopaedic applications." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37300.
Full textAbstract:
Novel surgical strategies for spinal disc repair are currently being developed that require materials that (1) possess the appropriate mechanical properties to mimic the tissue the material is replacing or repairing and (2) maintain their mechanical function for long durations without negatively affecting the tissue response of adjacent tissue (i.e. bone). Polymers formed through photopolymerization have emerged as candidate biomaterials for many biomedical applications, but these materials possess limited toughness in vivo due to the presence of water inherent in most tissues. Therefore, the overall objective of this research was to develop photopolymerizable (meth)acrylate networks that are both mechanically and biologically compatible under physiological conditions to be implemented in spinal repair procedures. The fundamental approach was to determine structure-property relationships between toughness and network structure in the presence of phosphate buffered saline (PBS) using several model copolymer networks in order to facilitate the design of photopolymerizable networks that are tough in physiological solution. It was demonstrated that networks toughness could be optimized in PBS by tailoring the Tg of the copolymer network close to body temperature and incorporating the appropriate "tough" chemical structures. The ability to maintain toughness up to 9 months in PBS was dependent upon the viscoelastic state and overall hydrophobicity of the network. In tandem, the effect of network chemistry and stiffness on the response of MG63 pre-osteoblast cells was assessed in vitro. The ability of MG63 cells to differentiate on (meth)acrylate network surfaces was found to be primarily dependent on surface chemistry with PEG-based materials promoting a more mature osteoblast phenotype than 2HEMA surfaces. Amongst each copolymer group, copolymer stiffness was found to regulate osteoblast differentiation in a manner dependent upon the surface chemistry. In general, photopolymerizable (meth)acrylate networks that were deemed "tough" were able to promote osteoblast differentiation in a manner comparable if not exceeding that on tissue culture polystyrene (TCPS). This research will impact the field of biomaterials by elucidating the interrelationships between materials science, mechanics, and biology.
22
Schuler, Martin. "Multifunctional titanium dental implant surface based on biochemically modified molecular assembly systems /." Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16914.
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Odendaal, Adriaan Izak. "Die ontwikkeling van 'n pasklaar-vervaardigde kunsmatige intervertebrale skyf-implantaat." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5149.
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Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010.<br>ENGLISH ABSTRACT: Current technology enables researchers to identify a broad spectrum of opportunities in the
biomedical industry to develop new and innovative products. Imaging technology, such as
Computerised Tomography (CT) scanners or Magnetic Resonance Imaging (MRI) scanners, allow
doctors to visualise a patient’s internal organs and bone structure in high quality three-dimensional
images.
Rapid Prototyping Technology (RPT) can already produce high quality complex parts, such as
concept parts for the automobile industry and medical models for preoperative planning. These parts
are divided into thin layers and manufactured layer by layer. At the same time the layers are joined
together to produce the desired part.
Generic artificial intervertebral disc implants already exist. However, these discs are only available in
standard geometrical dimensions. The possibility of using imaging technology and RPT to design and
manufacture a customized, patient specific implant will be investigated.
A simple design (ball and socket) is used to illustrate the design process of a customized disc. It
should be noted that this project does not attempt to design a new artificial intervertebral disc implant,
but rather describes the design process.
The research question is: How accurate can the customised disc implant’s inverse geometry represent
the geometry of the vertebrae’s endplates?
A preliminary research was done and the results were used to calculate the sample size for this study.
A cadaver, provided by Stellenbosch University’s Faculty of Health Sciences’ Anatomy and
Histology Department, was CT scanned. The L4- and L5-vertebrae were dissected, cleaned and
measured using a photogrammetry measuring machine.
Meanwhile, the data gathered from the CT scan is used to design the customised disc implant. The
disc is manufactured from Ti6Al4V using a RPT technique called Direct Metal Laser Sintering. After
the part is manufactured it is also measured using a photogrammetry measuring machine.
The photogrammetry data from the vertebrae and the manufactured customised disc implant are
compared, analysed and a hypothesis is formed. It can now be determined, with a certain degree of
confidence, how accurate the customised disc implant’s geometry can represent the geometry of the
vertebrae’s endplates.
The design of a customised disc implant demands many work hours from a qualified engineer or
designer, which in turn increases the production costs. This study describes a user-friendly program
which will semi-automate the design process. Only limited input from the physician will be required.
This program will decrease design time, which will have a direct effect on the production costs. The
manufacturing costs are investigated as well.
The results from this study indicates that it is possible to design a customized prosthetic, with the help
of a custom disc generator, within 27 minutes. The customized disc can then be manufactured with an
accuracy of 0.37 mm using rapid prototyping.<br>AFRIKAANSE OPSOMMING: Huidige tegnologie maak dit vir navorsers moontlik om ʼn breë spektrum geleenthede in die
biomediese bedryf te identifiseer en nuwe produkte te ontwikkel. ʼn Pasiënt kan met ʼn
Gerekenariseerde Tomografie (GT) -flikkergram of ʼn Magnetiese Resonansiebeelding (MRB) -
masjien geskandeer word om sodoende ʼn drie-dimensionele beeld van sy of haar interne organe en
beenstrukture te verkry.
Deur gebruik te maak van snelle prototiperingstegnologie (SPT) kan daar alreeds enige komplekse
geometriese vorm vervaardig word. Hierdie tegnologie word ingespan om parte, ontwerp met die hulp
van RGO (Rekenaargesteunde Ontwerp), te vervaardig. Die spesifieke part word in dun lae opgedeel
en daarna laag vir laag vervaardig. Terselfdertyd word die lae aan mekaar geheg, totdat die gewenste
vorm gegenereer is.
Die moontlikheid om ʼn GT-flikkergram én SPT te gebruik, met die doel om ʼn pasklaar-vervaardigde,
persoon-spesifieke implantaat te ontwerp en te vervaardig, word in hierdie projek ondersoek.
Daar bestaan alreeds generiese kunsmatige intervertebrale skyf-implantate (KISI’s). Hierdie skywe
word egter beperk deurdat dit slegs in standaard geometriese dimensies vervaardig word. Met dié
projek word die moontlikheid van ʼn pasklaar-vervaardigde intervertebrale skyf-implantate (PVKISI)
vir ʼn bepaalde pasiënt, ondersoek. ʼn Eenvoudige meganiese ontwerp (bal-en-pootjie) word gebruik
om die ontwerpproses van ʼn pasklaar-skyf in hierdie projek te beskryf. Let daarop dat die projek nie
poog om ʼn nuwe kunsmatige intervertebrale skyf te ontwerp nie, maar om die ontwerpproses te
beskryf.
Die vraag wat ondersoek word, is: Hoe akkuraat kan ʼn PVKISI die inverse geometrie van die pasiënt
se intervertebrale kontakoppervlaktes voorstel?
ʼn Voorafgaande ondersoek is gedoen en die resultate is gebruik om die steekproef-grootte vir hierdie
studie te bepaal. ʼn Kadawer, voorsien deur die Universiteit van Stellenbosch se Fakulteit
Gesondheidwetenskappe se Departement Anatomie en Histologie, is met ʼn GT-flikkergram
geskandeer. Die L4- en L5-werwels is gedissekteer, skoon gemaak en met ʼn fotogrammetriemeetmasjien
gemeet.
Intussen is die data, verkry van die GT-flikkergram, gebruik om die PVKISI te ontwerp. Die PVKISI
is van Ti6Al4V vervaardig deur Direkte Metaal Laser-Sintering (DMLS). Die part is ook met ʼn
fotogrammetrie-meetmasjien gemeet.
Die fotogrammetrie-data van die werwels en die PVKISI is vergelyk, geanaliseer en ʼn hipotese is daar
gestel. Daar kan dus met statistiese sekerheid bepaal word hoe akkuraat die PVKISI die inverse
geometrie van die intervertebrale kontakoppervlaktes kan voorstel.
Die ontwerp van ʼn PVKISI vereis baie werksure van ʼn gekwalifiseerde ingenieur of ontwerper, wat
veroorsaak dat die vervaardigingskoste van so ʼn implantaat kan verhoog. In dié projek word ʼn
gebruikersvriendelike koppelprogram beskryf wat die ontwerpproses semi-outomatiseer. Daar sal
slegs beperkte bystand van die betrokke medici vereis word. Dié koppelprogram behoort heelwat te
bespaar aan die hoeveelheid werksure bestee aan die ontwerp van die PVKISI, wat direk die koste van
ʼn implantaat sal verlaag. Die kostes vir die vervaardiging van die PVKISI met DMLS is ook
ondersoek om te bepaal hoe kostes bespaar kan word.
Daar is getoon dat ʼn pasklaar-prostese se kontakoppervlaktes met ʼn akkuraatheid van 0.37 mm, deur
snelle prototipering, vervaardig kan word. Deur van die koppelprogram, wat in die studie beskryf
word, gebruik te maak, sal dit moontlik wees om ʼn pasklaar-protese binne 27 minute te ontwerp.
24
Wilms, Marcus. "Electrical receptive fields and cortical activation spread in response to electrical retina stimulation assessment of spatio-temporal resolution for a retina implant /." [S.l.] : [s.n.], 2001. http://archiv.ub.uni-marburg.de/diss/z2002/0084/.
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Gökcen, Röhlig Bilge. "The use of angulated implants in the maxillary tuberosity region a 3-dimensional finite element analysis study /." [S.l.] : [s.n.], 2004. http://archiv.ub.uni-marburg.de/diss/z2004/0657/.
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De, Beer Neal. "Development of a process chain for digital design and manufacture of patient-specific intervertebral disc implants with matching endplate geometries." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6564.
Full textAbstract:
Thesis (PhD (Industrial Engineering))--University of Stellenbosch, 2011.<br>ENGLISH ABSTRACT: Back pain is a common concern amongst a growing population of people across the world today, where in
most cases the pain can become unbearable resulting in major lifestyle adjustments. Seventy to eighty
percent of the population of the Western world experiences low-back pain at one time or another. Pain can
be produced as a worn disc becomes thin, narrowing the space between the vertebrae. Pieces of the
damaged disc may also break off and cause irritation to the nerves signalling back pain.
Depending on the severity of a patient’s condition, and after conservative treatment options have been
exhausted, a disc replacement surgery (arthroplasty) procedure may be prescribed to restore spacing
between vertebrae and relieve the pinched nerve, while still maintaining normal biomechanical movement.
Typical complications that are however still observed in some cases of disc implants include: anterior
migration of the disc, subsidence (sinking of disc) and lateral subluxation (partial dislocation of a joint).
Issues such as function, correct placement and orientation, as well as secure fixation of such a disc implant
to the adjacent vertebrae are highly important in order to replicate natural biomechanical behaviour and
minimise the occurrence of the complications mentioned.
As various imaging and manufacturing technologies have developed, the option for individual, patientspecific implants is becoming more of a practical reality than it has been in the past. The combination of CT
images and Rapid Manufacturing for example is already being used successfully in producing custom
implants for maxilla/facial and cranial reconstructive surgeries.
There exists a need to formalise a process chain for the design and manufacture of custom-made
intervertebral disc implants and to address the issues involved during each step. Therefore this study has
investigated the steps involved for such a process chain and the sensible flow of information as well as the
use of state-of-the-art manufacturing technologies. Strong emphasis was placed on automation of some of
the processes as well as the user-friendliness of software where engineers and surgeons often need to
work together during this multi-disciplinary environment.
One of the main benefits for customization was also investigated, namely a reduction in the risk and
potential for implant subsidence. Stiffness values from pressure tests on vertebrae were compared
between customized implants and implants with flat endplate designs. Results indicated a statistically
significant improvement of customized, endplate matching implants as opposed to flat implant endplates.
Therefore it may be concluded that the use of customized intervertebral disc implants with patient specific
endplate geometry may decrease the risk and potential for the occurrence of subsidence.<br>AFRIKAANSE OPSOMMING: Rugpyn is ‘n algemene bekommernis vir ‘n groeiende populasie van mense in die wêreld vandag, waar in
meeste gevalle die pyn ondraagbaar kan raak en groot leefstyl aanpassings vereis. Sewentig tot tagtig
persent van die populasie in die Westerse wêreld ondervind lae rugpyn op een of ander stadium. Die pyn
kan veroorsaak word deur ‘n intervertebrale skyf wat verweer en dunner word, en veroorsaak dat die
spasie tussen die vertebrae vernou. Stukkies van die beskadigde skyf mag ook afbreek en irritasie aan die
senuwees veroorsaak wat verdere pyn kan veroorsaak.
Afhangende van die ernstigheid van ‘n pasiënt se geval, en nadat opsies vir konservatiewe behandeling
uitgeput is, kan ‘n skyf vervangings-prosedure (artroskopie) voorgeskryf word om die spasie tussen die
vertebrae te herstel en sodoende die geknypte senuwee te verlos. Die skyf vervanging herstel spasiëring
tussen vertebrae terwyl die normale biomeganiese beweging ook behoue bly, in teenstelling met ‘n fusieprosedure wat die betrokke vertebrae aanmekaar vasheg en normale beweging belemmer. Tipiese
komplikasies wat egter steeds na ‘n skyf vervanging in sommige gevalle waargeneem word sluit in: anterior
migrasie van die inplantaat, insinking, sowel as laterale sublukasie (gedeeltelike dislokasie van ‘n gewrig).
Faktore soos funksie, korrekte posisionering en orientasie, sowel as vashegting van so ‘n skyf inplantaat tot
die aanliggende vertebrale bene is besonder belangrik om natuurlike biomeganiese beweging te herstel en
sodoende bogenoemde komplikasies te verminder.
Soos wat verskeie beeldings- en vervaardigingstegnologië verbeter het oor die laaste dekade, het die
moontlikheid vir individuele, pasiënt-spesifieke inplantate al hoe meer ‘n praktiese realiteit begin word. Die
kombinasie van Gerekenariseerde Tomografie (GT), tesame met Snel Vervaardiging word byvoorbeeld
reeds suksesvol aangewend tydens die ontwerp en vervaardiging van pasiënt-spesifieke inplantate vir
maksilla- en kraniale rekonstruktiewe chirurgie. Daar bestaan egter ‘n behoefte om ‘n formele
prosesketting vir die ontwerp en vervaardiging van pasiënt-spesifieke intervertebrale skyf inplantate te
ontwikkel en om belangrike faktore tydens elke stap noukeurig te beskryf.
Hierdie studie het na die verskillende stappe in die prosesketting gekyk om ‘n sinvolle vloei van informasie
en benutting van hoë gehalte vervaardigingstegnologië saam te snoer. Sterk klem was gelê op
outomatisering van prosesse asook gebruikersvriendelikheid van sagteware waar ingenieurs en medici
dikwels saam moet werk tydens hierdie kruisdissiplinêre omgewing.
Een van die hoof verwagte voordele met die gebruik van pasklaar skyf inplantate, naamlik die vermindering
van moontlike insinking van die inplantaat in die been, is ook ondersoek. Die ondersoek het druktoetse
behels en die vergelyking van ooreenstemmende styfheid tussen inplantate wat die kontoer van die bene
volg teenoor gewone plat eindplate. Die resultate was statisties beduidend in die guns van die pasklaar
inplantate wat die beenkontoere gevolg het, en bewys dus dat die risiko vir insinking verminder is.
27
Frei, Christian. "The thread injection : thread transport in circular pipe flow applied in a minimally invasive openporous implant system for endonasal surgery /." [S.l.] : [s.n.], 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13549.
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Ueberberg, Johanna [Verfasser], and Dirk [Akademischer Betreuer] Wähnert. "Schätzung und biomechanische Validierung der Knochen-Implantat-Stabilität basiert auf klinischen QCT Scans / Johanna Ueberberg ; Betreuer: Dirk Wähnert." Münster : Universitäts- und Landesbibliothek Münster, 2020. http://d-nb.info/1213351014/34.
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Fluck, Daniel. "Ion-implanted KNbO₃ waveguides for blue-light second-harmonic generation /." Zürich, 1995. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11225.
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Majkić, Aleksej. "Electro-optically tunable microring resonators in fluorine-implanted lithium niobate /." Zürich : ETH, 2009. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18179.
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Goncalves, Flavia. "Comparison of the effectiveness of mechanical and chemical procedures to decontaminate titanium disks and to promote osteoblast attachment." Thesis, NSUWorks, 2015. https://nsuworks.nova.edu/hpd_cdm_stuetd/17.
Full textAbstract:
Objective: This study was conducted to determine the effectiveness of physical and mechanical disinfection of P. gingivalis from implant disks and to evaluate bone cells growth and attachment to the disks. Background. Each year, over three million of Americans replacing missing teeth with dental implants. An inflammatory process around an implant that causes bone loss, characterizes peri-implantitis, first diagnosed in the 1980s. The prevalence is approximately 22%. To date, no treatment protocol of peri-implantitis has been proposed. Methods. 207 implants disks. Four different implant surfaces utilized. Disks were contaminated by p. gingivalis and consequentially disinfected by physical means (spraying prophy jet, titanium brush, and ultrasonic activation) and chemically by Hydrogen Peroxide 3%, 0.12% Chlorhexidine Gluconate, and Sodium Bicarbonate. Osteoblasts were added to the disks. Growth factors (Emdogain and Gem21S) were used in two groups. Osteoblast vitality, attachment and morphology were evaluated. Results. On 3iT3 the all disinfection methods had similar results. On Osseotite and Nanotite surfaces, the citric acid combined with ultrasonic activation granted the worse results. Hence, disks that did not have the surface altered by physical decontamination had most cells attached. Hydrogen Peroxide 3% showed to be the most biocompatible and 0.12% Chlorhexidine gluconate showed most cellular toxicity. Implant coating did not influence osteoblast attachment. Growth factors did not promote osteoblast attachment. Conclusion: Further investigations are necessary.
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Ferreira, Jaqueline Aparecida Gurgacz. "Educa??o a dist?ncia : estudo da mudan?a organizacional no processo de implanta??o da modalidade EaD em uma institui??o de ensino superior." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2015. http://tede2.pucrs.br/tede2/handle/tede/6304.
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Previous issue date: 2015-06-29<br>The current dissertation is formed by a study with a Higher Education as object, located in Cascavel, in the West region in the State of Parana. This institution has 15 years of experience in classroom teaching, and since 2014, it is on the experience of the introduction of Distance Education. In this way the research sought through the analysis categories of the Schr?eder?s study (2009), understanding the process of organizational change caused by this introduction. The project presents the theories of Organizational Change and of Distance Education. The research has as methodological approach the qualitative perspective, representing a study of case, with exploratory feature, with triangulation of data sources (observations, documents and interviews). The interviews were developed with 24 technical and scientific members from the Distance Education of the institution, and they were analyzed through content analysis. Along with this study, there are the documental analysis and the observation notes by the researcher, being them: Values, Contents, Technology, Management, Institutionalization and Interaction. Although it has identified as a process limiter the fact that the Distance Education still being implemented, the research points to significant elements to the analysis, highlighting in the results, mainly, the level of cultural impact which the implementation promotes until the studied point, as well as the need to create strategic management tools to the process of Distance Education management.<br>A presente disserta??o constitui-se de um estudo que possui como objeto uma IES ? Institui??o de Ensino Superior, situada em Cascavel, na regi?o oeste do Estado do Paran?. A referida IES possui 15 anos de experi?ncia com o ensino na modalidade presencial e, desde o ano de 2014, encontra-se diante da experi?ncia da implanta??o da modalidade EaD. Desse modo, a pesquisa buscou, por meio das categorias de an?lise do estudo de Schr?eder (2009), compreender o processo de mudan?a organizacional desencadeado por esta implanta??o. Como referenciais te?ricos centrais, predominam os temas referentes ? Mudan?a Organizacional e ? Educa??o a Dist?ncia. A pesquisa tem como aporte metodol?gico a perspectiva qualitativa, constituindo, portanto, um estudo de caso, de car?ter explorat?rio, com triangula??o de fontes de dados (observa??es, documentos institucionais e entrevistas). As entrevistas foram realizadas com 24 integrantes do corpo t?cnico e cient?fico da EaD da IES estudada, e analisadas por meio de an?lise de conte?do. Combinaram-se a este estudo, a an?lise documental e as notas de observa??o por parte da pesquisadora, observadora participante do processo. Foram analisadas 06 categorias, sendo elas: Valores, Conte?dos, Tecnologia, Gest?o, Institucionaliza??o e Intera??o. Embora tenha se verificado como limitador do processo o fato de a EaD ainda estar em implanta??o, a pesquisa aponta elementos significativos ? an?lise, destacando-se nos resultados, principalmente, o n?vel de impacto cultural que a implanta??o promove at? o ponto estudado, bem como a necessidade de cria??o de ferramentas estrat?gicas de gest?o para o processo de gest?o da EaD.
33
Lok, Peter Yin Cheung. "Development of a novel minimally invasive scaffold system for spinal disc repair." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/12583.
Full textAbstract:
Debilitating chronic back pain caused by severe spinal disc degeneration leads to loss of mobility, affecting quality of life, a significant loss of productivity for the employee and the employer. Currently available surgical intervention options, such as spinal fusion and total disc replacement, seeking only to alleviate pain, are not only invasive, but fail to address the underlying biological causes of spinal disc degeneration, or restore normal physiological spinal motion. Recently proposed tissue engineering approaches focus on stopping and reversing the degenerative cascade, which has a promising regenerative effect, though not without significant challenges before a clinical application is made available, including tumourigenesis risks and proof of efficacy. A minimally invasive nucleus pulposus replacement option, which preserves the competent annulus fibrosis, while replacing the removed degenerated nucleus tissue with a prosthesis, provides an alternative for early disc degeneration, though most commercially available types are at clinical trial stages. There is an opportunity for developing a minimally invasive nucleus pulposus replacement type spinal implant system that restores disc biomechanics and addresses biological degenerative causes. This body of work details the design, development, fabrication, prototyping, verification and validation of this novel implant system. The implant system consisted of a configuration of scaffold and hydrogel interpenetrating polymer network composite delivered minimally invasively via a cannula system, after the nucleus pulposus is removed in a nucleotomy with a set of specialised tools. Implantation of the novel prosthesis was shown to be successful in various spinal disc models, in meeting identified design and functional requirements, including biomechanical loading, resistance to expulsion and radiopacity.
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Cavalcanti, Maria da Concei??o Monteiro. "A expans?o do ensino superior ? dist?ncia no IFPB: um estudo da implanta??o do Curso de Administra??o P?blica no ?mbito do Programa Nacional de Administra??o P?blica - PNAP." PROGRAMA DE P?S-GRADUA??O EM EDUCA??O, 2016. https://repositorio.ufrn.br/jspui/handle/123456789/21428.
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Previous issue date: 2016-03-31<br>A presente tese, intitulada ?A Expans?o do Ensino Superior a Dist?ncia no IFPB: Uma An?lise da Implanta??o do Curso de Gradua??o em Administra??o P?blica no ?mbito do Programa Nacional de Administra??o P?blica - PNAP?, objetiva analisar a pol?tica de expans?o do ensino superior na modalidade a dist?ncia no IFPB, tendo como refer?ncia a implementa??o do Bacharelado de Administra??o P?blica/PNAP e suas repercuss?es na cultura organizacional e no trabalho docente do IFPB Campus Jo?o Pessoa, partindo do pressuposto de que as modifica??es ocorridas no sistema educacional brasileiro entre o final do s?culo XX e o in?cio do s?culo XXI ocorreram em atendimento ?s pol?ticas de cunho neoliberal, orientadas por organismos internacionais, a exemplo do Banco Mundial e da Unesco. As diretrizes dessas pol?ticas para o ensino superior propiciaram a diversifica??o institucional e a utiliza??o da educa??o a dist?ncia como estrat?gias de expans?o. Essas novas orienta??es trouxeram para os Institutos Federais de Educa??o Ci?ncia e Tecnologia a amplia??o das suas compet?ncias e o desafio de ofertar a educa??o superior na modalidade a dist?ncia. A oferta do curso de Bacharelado em Administra??o P?blica no ?mbito do PNAP ? exemplo de a??es de expans?o induzida pela a??o do Minist?rio de Educa??o, em parceria com a Universidade Aberta do Brasil (UAB). A natureza desta investiga??o requereu sua instrumentaliza??o por meio da pesquisa qualitativa e de estudo de caso. Como procedimentos metodol?gicos, utilizou-se a an?lise documental e a entrevista semiestruturada, aplicada a gestores e docentes que atuaram no projeto BAP/PNAP/UAB. O estudo concluiu que, com a ades?o ? oferta do curso de Bacharelado em Administra??o P?blica EaD, o IFPB cumpriu seu papel enquanto institui??o da rede federal de atendimento a uma pol?tica p?blica, no entanto, a implementa??o de um curso dessa natureza sem uma estrutura adequada provocou v?rias mudan?as na cultura organizacional da institui??o. A utiliza??o da EaD em um espa?o institucional detentor de uma cultura muito forte de ensino presencial exigiu dos gestores e docentes uma nova postura profissional para se adequar ?s novas exig?ncias para o trabalho com a modalidade a dist?ncia. No que se refere ao trabalho docente daqueles que atuam no PNAP, este se apresenta com aspectos de intensifica??o e precariza??o, o que pode ocasionar preju?zo para a qualidade do curso desenvolvido na modalidade de EaD, comprometendo o desempenho da institui??o de modo geral.<br>The objective of this thesis is to analyse the policy for the expansion of higher education
within the modality of long-distance learning at IFPB. The reference for this is the
implementation of the Bachelor?s Degree in Public Administration/NPPA and its repercussion
on the organizational culture and teaching work of the IFPB campus in Jo?o Pessoa. This
proposal is relevant based on the modifications that occurred in the Brazilian educational
system between the end of the 20th century and the beginning of the 21st century, which
resulted from, amongst other aspects, the attending to of neo-liberal type policies that were
put forward by international organisms like the World Bank and UNESCO. The directives of
these organizations for higher education provided for flexibility, institutional diversification
and the utilization of long-distance learning as expansion strategies. When you refer
specifically to the Federal Institutes of Scientific and Technological Education, they increased
their competences and the challenge of offering higher education in the modality of longdistance
learning. The offering of the Bachelor?s Degree course in Administration in the ambit
of NPPA is an example of expansion actions induced by the action of the Ministry of
Education, in partnership with the Universidade Aberta do Brasil (UAB). In this way, the
thesis is that a higher education expansion policy at IFPB, through long-distance learning, is
provoking a restructuring of the institution, which traditionally offered presence-based
courses including professors and methodologies appropriate for this type of education. With
the creation of higher education courses through long-distance learning, this institution is
gradually changing its organizational culture, based on the premise that long-distance learning
requires from the teaching body the learning of new methodologies, and new teaching
practices to take place outside of the classroom, and resulting in serious repercussions for the
teaching body. This empirical investigation required the use of qualitative research and case
studies. The methodological procedures used were the analysis of documents and a semistructured
interview applied to managers and professors that are part of the Bachelor?s Degree
in Public Administration/NPPA/UAB. The study concluded that, with the adhesion to the
offering of the Bachelor?s Degree in Public Administration through Long-Distance Learning,
IFPB fulfilled its role as an institution of the federal network attending to a public policy.
However, the implementation of a course of this nature without an adequate structure for this
demand provoked various changes in the organizational culture of the institution. The
utilization of long-distance learning in an institutional space that has a very strong classroombased
teaching culture demanded a new professional posture from the managers and
professors in order to be able to attend to the new requirements of this work within the
modality of long-distance learning. In relation to the teaching work of those that work within
NPPA, this presented aspects of intensification and insecurity, which could result in harming
the quality of the course developed within the modality of long-distance learning, thus
compromising the general performance of the institution.
35
Bhattacharya, Sanghita. "Predictive Finite Element Modeling of Artificial Cervical Discs in a Ligamentous Functional Spinal Unit." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302138650.
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Tsai, Cheng Tang, and 蔡承唐. "The innovative design of spinal disc implant." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/00770541869979891499.
Full textAbstract:
碩士<br>長庚大學<br>醫療機電工程研究所<br>101<br>Degenerative disc disease is a major reason for low back pains that affect people’s life. Recently, total disc replacement surgery has been developed to treat degenerative disc disease. In this thesis, a novel artificial disk implant was designed, analyzed, manufactured and tested. The implant is a compact device which is able to absorb impact and simulate the spinal disc nuclear function. The device is designed to limit the range of motion by spherical geometric contact to reduce facet joint loading. Also, a finite element method is applied to analysis the stress distribution for three different endplate shapes to obtain the most feasible shape. Both disc spring and polyethylene are applied as a cushion material to absorb impact. Finally, a strength test is applied to verify the tolerance of the vertical pressure of this design.
Result: ellipse shape of the endplate can averagely distribute the stress. Using disc spring as the shock absorbing material is better than polyethylene because of reasonable deformation. According to the test of the constrained range of motion, it’s close to the angle we set, thus this design can successfully constrain the range of motion. Afterwards we expect to search for biomaterial springs which can be used in human test and help those who are suffered by low back pain.
37
Parker, Christopher Daniel. "The development of a posterior dynamic stabilisation implant indicated for thoraco-lumbar disc degeneration / Christopher Daniel (Chris) Parker." Thesis, 2013. http://hdl.handle.net/10394/12254.
Full textAbstract:
Posterior lumbar spinal dynamic stabilisation devices are intended to relieve the pain of spinal
segments while prolonging the lifespan of adjacent intervertebral discs. This study focuses on the
design of such a device, one that has the correct stiffness to stabilise the spinal segment by the correct
amount.
An initial literature survey covers contemporary topics related to the lumbar spine. Included topics are
lumbar anatomy and kinematics, pathology of degenerative disc disease and treatment thereof, other
spinal disorders such as spondylolisthesis and spinal stenosis, as well as the complications associated
with lumbar dynamic stabilisation. The influence of factors such as fatigue and wear, as well as the
properties of appropriate biomaterials are considered when determining the basis of the device design
and development.
Stabilising the spinal segment begins with correct material selection and design. Various designs and
biomaterials are evaluated for their stiffness values and other user requirements. The simplest design,
a U-shaped spring composed of carbon fibre-reinforced poly-ether-ether-ketone (CFR-PEEK) and
anchored by polyaxial titanium pedicle screws, satisfies the most critical user requirements.
Acceptable stiffness is achieved, fatigue life of the material is excellent and the device is very
imaging-friendly. Due to financial constraints, however, a simpler concept that is cheaper and easier
to rapid prototype was chosen. This concept involves a construct primarily manufactured from the
titanium alloy Ti6Al4V extra-low interstitial (ELI) and cobalt-chrome-molybdenum (CCM) alloys.
The first rapid prototype was manufactured using an additive manufacturing process (3D-printing).
The development of the device was performed in three main stages: design, verification and
validation. The main goal of the design was to achieve an acceptable stiffness to limit the spinal
segmental range of motion (ROM) by a determined amount. The device stiffness was verified through
simple calculations. The first prototype’s stiffness was validated in force-displacement tests. Further
validation, beyond the scope of this study, will include fatigue tests to validate the fatigue life of the
production-ready device.<br>MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014