Abteilung von der Armee #W81XWH-08-1-0587, #W81XWH-15-1-0006; Ball State University 2010 ASPiRE gewähren.

<ol>
	<li>Brukner, P., Bennell, K., Matheson, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Stress fracture. , (1999).</li><li>Zadpoor, A., Nikooyan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+relationship+between+lower-extremity+stress+fractures+and+the+ground+reaction+force:+A+systematic+review.">The relationship between lower-extremity stress fractures and the ground reaction force: A systematic review.</a> Clin Biomech. 26, 23-28 (2011).</li><li>Matheson, G. O., Clement, D. B., McKenzie, D. C., Taunton, J. E., Lioyd-Smith, D. R., Maclntyre, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress+fractures+in+athletes.+A+study+of+320+cases.">Stress fractures in athletes. A study of 320 cases.</a> Am J Sports Med. 15, 46-58 (1987).</li><li>Bennell, K., Grimston, S., Burr, D., Milgrom, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Risk+factors+for+developing+stress+fractures.">Risk factors for developing stress fractures.</a> Musculoskeletal fatigue and stress fractures. , 15-33 (2001).</li><li>Milgrom, C., Giladi, M., Stein, M., Kashtan, H., Margulies, J. Y., Chisin, R., Stenberg, R., Aharonson, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress+fractures+in+military+recruits.+A+prospective+study+showing+an+unusually+high+incidence.">Stress fractures in military recruits. A prospective study showing an unusually high incidence.</a> J Bone Joint Surg Br. 67, 732-735 (1985).</li><li>Almeida, S. A., Williams, K. M., Shaffer, R. A., Brodine, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidemiological+patterns+of+musculoskeletal+injuries+and+physical+training.">Epidemiological patterns of musculoskeletal injuries and physical training.</a> Med Sci Sports Exerc. 31, 1176-1182 (1999).</li><li>Jones, B. H., Knapik, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+training+and+exercise-related+injuries,+surveillance,+research+and+injury+prevention+in+military+populations.">Physical training and exercise-related injuries, surveillance, research and injury prevention in military populations.</a> Sports Med. 27, 111-125 (1999).</li><li>Jones, B. H., Thacker, S., Gilchrist, J., Kimsey, C. D., Sosin, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevention+of+lower+extremity+stress+fractures+in+athletes+and+soldiers:+a+systematic+review.">Prevention of lower extremity stress fractures in athletes and soldiers: a systematic review.</a> Epidemiol Rev. 24, 228-247 (2002).</li><li>Voloshin, A., Wosk, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vivo+study+of+low+back+pain+and+shock+absorption+in+the+human+locomotor+system.">An in vivo study of low back pain and shock absorption in the human locomotor system.</a> J Biomech. 15, 21-27 (1982).</li><li>Burr, D. B., Milgrom, C., Fyhrie, D., Forwood, M., Nyska, M., Finestone, A., Hoshaw, S., Saiag, E., Simkin, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+measurement+of+human+tibial+strains+during+vigorous+activity.">In vivo measurement of human tibial strains during vigorous activity.</a> Bone. 18, 405-410 (1996).</li><li>Ekenman, I., Halvorsen, K., Westblad, P., Fellander-Tsai, L., Rolf, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+reliability+and+validity+of+an+instrumented+staple+system+for+in+vivo+measurement+of+local+bone+deformation.+An+in+vitro+study.">The reliability and validity of an instrumented staple system for in vivo measurement of local bone deformation. An in vitro study.</a> Scand J Med Sci Sports. 8, 172-176 (1998).</li><li>Lanyon, L. E., Hampson, W. G., Goodship, A. E., Shah, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bone+deformation+recorded+in+vivo+from+strain+gauges+attached+to+the+human+tibial+shaft.">Bone deformation recorded in vivo from strain gauges attached to the human tibial shaft.</a> Acta Orthop Scand. 46, 256-268 (1975).</li><li>Ekenman, I., Halvorsen, K., Westblad, P., Tsai, L. F., Rolf, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Local+bone+deformation+at+two+predominant+sites+for+stress+fractures+of+the+tibia:+an+in+vivo+study.">Local bone deformation at two predominant sites for stress fractures of the tibia: an in vivo study.</a> Foot Ankle Int. 19, 479-484 (1998).</li><li>Milgrom, C., Finestone, A., Levi, Y., Simkin, A., Ekenman, I., Mendelson, S., Millgram, M., Nyska, M., Benjuya, N., Burr, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Do+high+impact+exercises+produce+higher+tibial+strains+than+running?.">Do high impact exercises produce higher tibial strains than running?.</a> Br J Sports Med. 34, 195-199 (2000).</li><li>Milgrom, C., Finestone, A., Simkin, A., Ekenman, I., Mendelson, S., Millgram, M., Nyska, M., Larsson, E., Burr, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In-vivo+strain+measurements+to+evaluate+the+strengthening+potential+of+exercises+on+the+tibial+bone.">In-vivo strain measurements to evaluate the strengthening potential of exercises on the tibial bone.</a> J Bone Joint Surg Br. 82, 591-594 (2000).</li><li>Al Nazer, R., Rantalainen, T., Heinonen, A., Sievanen, H., Mikkola, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexible+multibody+simulation+approach+in+the+analysis+of+tibial+strain+during+walking.">Flexible multibody simulation approach in the analysis of tibial strain during walking.</a> J Biomech. 41, 1036-1043 (2008).</li><li>Al Nazer, R., Klodowski, A., Rantalainen, T., Heinonen, A., Sievanen, H., Mikkola, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+full+body+musculoskeletal+model+based+on+flexible+multibody+simulation+approach+utilised+in+bone+strain+analysis+during+human+locomotion.">A full body musculoskeletal model based on flexible multibody simulation approach utilised in bone strain analysis during human locomotion.</a> Comput Method Biomec. 14, 573-579 (2011).</li><li>Johnson, M. A., Moradi, M. H., Crowe, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> PID control: new identification and design methods. , 543 (2005).</li><li>Craig, R. R., Bampton, M. C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coupling+of+substructures+for+dynamics+analysis.">Coupling of substructures for dynamics analysis.</a> American Institute of Aeronautics and Astronautics Journal. 6, 1313-1319 (1968).</li><li>Wasfy, T. M., Noor, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Computational+strategies+for+flexible+multibody+systems.">Computational strategies for flexible multibody systems.</a> Appl Mech Rev. 56, 553-613 (2003).</li><li>Kadaba, M. P., Ramakrishnan, H. k., Wootten, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+lower+extremity+kinematics+during+level+walking.">Measurement of lower extremity kinematics during level walking.</a> J Orthop Res. 8, 383-392 (1990).</li><li>Schwartz, M. H., Rozumalski, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+method+for+estimating+joint+parameters+from+motion+data.">A new method for estimating joint parameters from motion data.</a> J Biomech. 38, 107-116 (2005).</li><li>Devita, P., Skelly, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+landing+stiffness+on+joint+kenetics+and+energetic+in+the+lower+extremity.">Effect of landing stiffness on joint kenetics and energetic in the lower extremity.</a> Med Sci Sports Exerc. 24, 108-115 (1992).</li><li>Dong, X. N., Guo, X. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+dependence+of+transversely+isotropic+elasticity+of+human+femoral+cortical+bone+on+porosity.">The dependence of transversely isotropic elasticity of human femoral cortical bone on porosity.</a> J Biomech. 37, 1281-1287 (2004).</li><li>Schileo, E., Taddei, F., Malandrino, A., Cristofolini, L., Viceconti, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subject-specific+finite+element+models+can+accurately+predict+strain+levels+in+long+bones.">Subject-specific finite element models can accurately predict strain levels in long bones.</a> J Biomech. 40, 2982-2989 (2007).</li><li>Pattin, C. A., Caler, W. E., Carter, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cyclic+mechanical+property+degradation+during+fatigue+loading+of+cortical+bone.">Cyclic mechanical property degradation during fatigue loading of cortical bone.</a> J Biomech. 29, 69-79 (1996).</li><li>Lifemodeler, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Lifemod Manual. , (2010).</li></ol>

Die Autoren erklären, dass sie keine finanziellen Interessenkonflikte.

Der Zweck dieser Studie war es, eine nicht-invasive Methode zum Bestimmen der Tibia Verformung bei hohen Impact-Aktivitäten zu entwickeln. Quantifizierung der Tibia Belastung durch Stoßbelastung führt zu einem besseren Verständnis der Stressfraktur der Tibia. In dieser Studie wurde ein fachspezifisches Muskel-Skelett-Modell entwickelt und Computersimulationen wurde durchgeführt, um die Bewegungen, Drop-Landung in einer Laborumgebung zu duplizieren. Die Wirkung der Tropfen-Podesthöhe auf tibiale Stamm wurde untersuc...

Knochenverletzungen Stress wie stressfrakturen, sind schwere Überlastungsschäden erfordern längere Erholung und entstehen erhebliche medizinische Kosten1,2. Stressfrakturen sind häufig sowohl in sportlichen und militärischen Populationen. Unter alle damit verbundenen Sportverletzungen, stressfrakturen entfallen 10 % der insgesamt3. Insbesondere verfolgen Sie Athleten Gesicht eine höhere Verletzungsrate bei 20 %4. Soldaten haben auch eine hohe Rate von stressfrakturen. Zum Beispiel eine Verletzungsrate von 6 % wurde für die US Army1 gemeldet und ein 31 % Verletzungsrate wurde in der israelischen Armee5berichtet. Unter allen gemeldeten stressfrakturen ist Stressfraktur der Tibia am häufigsten eine6,7,8.
Sport und körperlichen Trainings mit einem höheren Risiko der Tibia Stressfraktur sind normalerweise verbunden mit hohen Boden Auswirkungen (z. B.springen, landen und schneiden). Während der Fortbewegung ist eine Bodentruppe Auswirkungen auf den Körper aufgetragen, wenn der Fuß den Boden berührt. Diese Kraft wird durch Muskel-Skelett-System und Schuhe abgeführt. Das Skelettsystem dient als eine Reihe von Hebel, so dass Muskeln, Kräfte zu absorbieren den Boden Auswirkungen9anzuwenden. Wenn die Beinmuskulatur Boden Auswirkungen angemessen reduzieren können, müssen die Unterkörper-Knochen die Restkraft aufnehmen. Knochenstruktur erleben Verformung während dieses Prozesses. Sich wiederholende Absorption der verbleibenden Auswirkungkraft führen Microdamages in den Knochen, die ansammeln und stressfrakturen zu werden. Bis heute, Informationen im Zusammenhang mit Knochen ist Reaktion auf externe Bodentruppen Auswirkungen begrenzt. Es ist wichtig zu untersuchen, wie der Schienbein Knochen reagiert auf die mechanische Belastung durch hohe Aufprallkräfte bei dynamischen Bewegungen eingeführt. Prüfung Schienbein Knochen Verformung bei hohen Impact Aktivitäten führen zu einem besseren Verständnis des Mechanismus der Stressfraktur der Tibia.
Konventionelle Techniken verwendet, um Knochen Verformung in Vivo Messen beruhen auf instrumentierten Dehnungsmessstreifen10,11,12,13,14,15. Chirurgische Eingriffe sind erforderlich, um Dehnungsmessstreifen auf Knochenoberfläche zu implantieren. Aufgrund des invasiven Charakters sind in Vivo Studien durch eine kleine Auswahl von Freiwilligen begrenzt. Darüber hinaus können die DMS nur eine kleine Region der Knochenoberfläche überwachen. Vor kurzem wurde eine nicht-invasive Methode, die Verwendung von Computer-Simulation zu analysieren, Knochen Belastung eingeführte16,17. Diese Methodik ermöglicht die Fähigkeit, Muskel-Skelett-Modellierung und numerische Simulationen verbinden Knochen Belastung während der menschlichen Bewegung zu studieren.
Ein Muskel-Skelett-Modell wird durch ein Skelett und Muskulatur dargestellt. Das Skelett besteht aus Knochen-Segmenten, die starre oder nicht verformbaren Körper sind. Skelettmuskeln sind als Controller mit dem Progressive-Integral-Derivat (PID) Algorithmus modelliert. Die dreimaligen PID-Regelung verwendet Fehler Einschätzung zum Ausgang Genauigkeit18verbessern. Im Wesentlichen versuchen PID-Regler, Muskeln darstellt, Körperbewegungen zu duplizieren, durch die Entwicklung von notwendigen Kräfte um Längenänderungen der Muskeln im Laufe der Zeit zu produzieren. PID-Reglers verwendet den Fehler in der Länge/Zeit-Kurve, um die Kraft für die Reproduktion der Bewegung zu ändern. Dieser Simulationsprozess erstellt eine praktikable Lösung zur Koordination aller Muskeln zusammenarbeiten, um das Skelett und die Bewegung des Körpers zu produzieren.
Ein oder mehrere Segmente in das Skelett des Muskel-Skelett-Modell können als flexible Einrichtungen zur Messung der Verformung ermöglichen modelliert werden. Zum Beispiel kann der Schienbein Knochen in eine endliche Anzahl von Elementen, aufzuschlüsseln besteht aus Tausenden von Elementen und Knoten. Die Wirkung der mechanischen Belastung der flexiblen Tibia kann durch finite Elemente (FE) untersucht werden. Die FE-Analyse berechnet die laden-Reaktion der einzelnen Elemente im Laufe der Zeit. Als die Zahl der Knochen Elemente und Knoten erheblich die Rechenzeit der FE-Analyse.
Um Rechenaufwand mit genaue Bewertung der flexiblen Körper Verformung zu reduzieren, hat FE Modalanalyse entwickelt und eingesetzt in der Automobil-und Luftfahrtindustrie19,20. Anstatt durch die Analyse einzelner FE Elemente Antworten auf mechanische Belastung im Zeitbereich, bewertet dieses Verfahren mechanische Reaktionen eines Objekts basierend auf unterschiedlichen Schwingungs-Frequenzen im Frequenzbereich. Diese Methode führt zu einem deutlichen Rückgang der Rechenzeit und gleichzeitig genaue Messung der Verformung20. Obwohl FE Modalanalyse ist weit verbreitet, mechanische Ermüdung in den Bereichen der Automobil- und Luftfahrtindustrie zu studieren, die Anwendung dieser Methode wurde sehr begrenzt in der Wissenschaft der menschlichen Bewegung. Al Nazer Et Al., verwendet eine Modalanalyse FE, um tibiale Verformung bei menschlichen Gang zu untersuchen und Förderung der Ergebnisse16,17berichtet. Ihre Methode war jedoch stark betroffen, nur mit begrenzten kinematische Daten aus einem Experiment, um die Computersimulationen zu fahren; Es gab keine wirkliche Auswirkung Bodentruppen verwendet, um die Simulationen zu unterstützen. Dieser Ansatz kann für das Studium geringen Auswirkungen Zeitlupen wie walking vertretbar sein, aber es ist keine praktikable Lösung, High Impact Bodenbewegungen zu studieren. Um Unterkörper-Knochen Reaktionen während der dynamischen hohe Schlagzähigkeit Aktivitäten zu untersuchen, ist es so wichtig, einen innovativen Ansatz, um die Einschränkungen der bisher gemeldeten Methode zugeordnet zu beheben zu entwickeln. Insbesondere eine Methode unter Verwendung genaue experimentelle kinematische Daten und Real Bodentruppen Auswirkungen müssen entwickelt werden. Daher war das Ziel dieser Studie ein fachspezifisches Muskel-Skelett-Modell um Mehrkörper dynamische Simulationen mit FE Modalanalyse, tibiale Belastung während hohe Schlagzähigkeit Aktivitäten zu untersuchen. Eine dynamische hohe Schlagzähigkeit-Bewegung vertreten durch Drop-Landungen aus unterschiedlichen Höhen wurde ausgewählt, um die Methode zu testen.

<table border="0" cellpadding="0" cellspacing="0" width="575">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:143px;">CT Scanner</td>
			<td style="width:123px;">GE Medical System</td>
			<td style="width:107px;">N/A</td>
			<td style="width:203px;">Light Speed VCT. For performing tibia CT scan.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Motion Capture System</td>
			<td>Vicon Inc</td>
			<td>N/A</td>
			<td>Vicon FX40 high speed cameras. For performing 3D motion capture.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Force plates</td>
			<td>AMTI Inc</td>
			<td>N/A</td>
			<td>Collecting 3D ground reaction forces</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Vicon Nexus</td>
			<td>Vicon Inc</td>
			<td>N/A</td>
			<td>Motion capture software program. For processing visual marker trajectory data.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Visual 3D</td>
			<td>C-Motion Inc</td>
			<td>N/A</td>
			<td>Biomechanics analysis software. For computing 3D kinematics and kinetics of human movements.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">MATLAB</td>
			<td>Mathworks Inc</td>
			<td>N/A</td>
			<td>Computer programming software. For performing raw data filtering, data conversion, and data processing.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">ADAMS 2012</td>
			<td>MSC Software Inc</td>
			<td>N/A</td>
			<td>Multibody dynamic computer simulation program.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">LifeMOD</td>
			<td>Lifemodeler Inc</td>
			<td>N/A</td>
			<td>A software Plug-in in ADAMS. For building human body musculo-skeletal models.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">MIMICS 13</td>
			<td>Materialise Inc</td>
			<td>N/A</td>
			<td>Image processing program. A 3D modeling tool to process imaging data. For creating 3D tibia model from CT scans.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">MARC 2012</td>
			<td>MSC Software Inc</td>
			<td>N/A</td>
			<td>Finite element analysis software. For performing volumn meshing, generating tibia FE model, and running modal FE analysis.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">SPSS 19</td>
			<td>IBM Inc</td>
			<td>N/A</td>
			<td>Statistical analysis software.</td>
		</tr>
	</tbody>
</table>

subject-specific musculoskeletal model for studying bone strain during dynamic motion

Knochenverletzungen Stress sind häufig in Sport und militärischen Trainings. Sich wiederholende große Auswirkungen Bodentruppen während des Trainings könnte die Ursache sein. Es ist wichtig, um festzustellen, die Wirkung der hohen Boden Auswirkungen am Unterkörper-Knochen Verformung zwingt, um die Mechanismen der Knochenverletzungen Stress besser zu verstehen. Konventionellen DMS-Messung wurde zur in-Vivo Tibia Verformung zu studieren. Diese Methode ist mit Einschränkungen auch Invasivität des Verfahrens, Einbindung von wenigen Versuchspersonen und begrenzte Belastung Daten aus kleinen Knochen Flächen verbunden. Die vorliegende Studie soll einen neuartigen Ansatz um Schienbein Knochen Belastung unter hohe Schlagzähigkeit Belastungsbedingungen studieren vorstellen. Eine fachspezifische Muskel-Skelett-Modell wurde geschaffen, um eine gesunde männliche (19 Jahre, 80 kg, 1.800 mm) darstellen. Eine flexible finite-Elemente-Tibia-Modell entstand anhand einer Computertomographie (CT) Scan der rechten Tibia des Subjekts. Labor-Motion-Capture wurde durchgeführt, um die Kinematik und Boden Reaktionskräfte des Drop-Landungen aus unterschiedlichen Höhen (26, 39, 52 cm) zu erhalten. Mehrkörper dynamischen Computersimulationen kombiniert mit einer Modalanalyse der flexiblen Tibia wurden durchgeführt, um die Tibia Belastung während Drop-Landungen zu quantifizieren. Berechnete Tibia-Stamm-Daten wurden in guter Übereinstimmung mit früheren in Vivo Studien. Es ist offensichtlich, dass dieser nicht-invasiven Ansatz zur Tibia Knochen Belastung während hohe Schlagzähigkeit Aktivitäten für eine große Kohorte studieren führt zu einem besseren Verständnis der Verletzung Mechanismus der Tibia stressfrakturen eingesetzt werden kann.

Ein gesundes kaukasischen Männchen (19 Jahre, Höhe 1.800 mm, Gewicht 80 kg) meldete sich freiwillig für die Studie. Vor der Datenerhebung das Thema überprüft und unterzeichnet die Einverständniserklärung vor der Teilnahme an der Studie von der Universität Institutional Review Board genehmigt. Das Experiment wurde unter der Deklaration von Helsinki durchgeführt. Der Versuch wurde basierend auf das folgende Protokoll durchgeführt.
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Watch this Scientific Journal Video about Subject-specific Musculoskeletal Model for Studying Bone Strain During Dynamic Motion at JoVE.com

Fachspezifisches Muskel-Skelett-Modell zur Untersuchung der Knochenbelastung bei dynamischer Bewegung | Bioingenieurwesen | Video

Subject-specific Musculoskeletal Model for Studying Bone Strain During Dynamic Motion

Bei der Landung Unterkörper-Knochen erleben Sie großen mechanische Belastungen und verformt werden. Es ist wichtig, Verformung der Knochen, besser zu verstehen, die Mechanismen der Knochen Druckverletzungen verbunden mit Auswirkungen zu messen. Ein neuer Ansatz, die Integration von fachspezifischen Muskel-Skelett-Modellierung und finite-Elemente-Analyse wird verwendet, um tibiale Belastung bei dynamischen Bewegungen zu messen.

Fachspezifische Muskel-Skelett-Modell für die Untersuchung von Knochen Belastung während der dynamischen Bewegung

Bone stress injuries are common in sports and military trainings. Repetitive large ground impact forces during training could be the cause. It is ...

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Musculoskeletal System

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9.6K Aufrufe.  Ball State University. Bei der Landung Unterkörper-Knochen erleben Sie großen mechanische Belastungen und verformt werden. Es ist wichtig, Verformung der Knochen, besser zu verstehen, die Mechanismen der Knochen Druckverletzungen verbunden mit Auswirkungen zu messen. Ein neuer Ansatz, die Integration von fachspezifischen Muskel-Skelett-Modellierung und finite-Elemente-Analyse wird verwendet, um tibiale Belastung bei dynamischen Bewegungen zu messen.

Serie: Subject-specific Musculoskeletal Model for Studying Bone Strain During Dynamic Motion

Microfabricated Platforms for Mechanically Dynamic Cell Culture

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or fundamental cell biology studies is limited by current bioreactor technologies, which cannot simultaneously apply a variety of mechanical stimuli to cultured cells. In order to address this issue, we have developed a series of microfabricated platforms designed to screen for the effects of mechanical stimuli in a high-throughput format. In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and further demonstrate how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

Mikrofabrizierten Plattformen für Mechanisch Dynamische Cell Culture

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or ...

Forschung

Biotechnik

Microfluidic Mixers for Studying Protein Folding

The process by which a protein folds into its native conformation is highly relevant to biology and human health yet still poorly understood. One reason for this is that folding takes place over a wide range of timescales, from nanoseconds to seconds or longer, depending on the protein1. Conventional stopped-flow mixers have allowed measurement of folding kinetics starting at about 1 ms. We have recently developed a microfluidic mixer that dilutes denaturant ~100-fold in ~8 &mu;s2. Unlike a stopped-flow mixer, this mixer operates in the laminar flow regime in which turbulence does not occur. The absence of turbulence allows precise numeric simulation of all flows within the mixer with excellent agreement to experiment3-4.
Laminar flow is achieved for Reynolds numbers Re &le;100. For aqueous solutions, this requires micron scale geometries. We use a hard substrate, such as silicon or fused silica, to make channels 5-10 &mu;m wide and 10 &mu;m deep (See Figure 1). The smallest dimensions, at the entrance to the mixing region, are on the order of 1 &mu;m in size. The chip is sealed with a thin glass or fused silica coverslip for optical access. Typical total linear flow rates are ~1 m/s, yielding Re~10, but the protein consumption is only ~0.5 nL/s or 1.8 &mu;L/hr. Protein concentration depends on the detection method: For tryptophan fluorescence the typical concentration is 100 &mu;M (for 1 Trp/protein) and for FRET the typical concentration is ~100 nM.
The folding process is initiated by rapid dilution of denaturant from 6 M to 0.06 M guanidine hydrochloride. The protein in high denaturant flows down a central channel and is met on either side at the mixing region by buffer without denaturant moving ~100 times faster (see Figure 2). This geometry causes rapid constriction of the protein flow into a narrow jet ~100 nm wide. Diffusion of the light denaturant molecules is very rapid, while diffusion of the heavy protein molecules is much slower, diffusing less than 1 &mu;m in 1 ms. The difference in diffusion constant of the denaturant and the protein results in rapid dilution of the denaturant from the protein stream, reducing the effective concentration of the denaturant around the protein. The protein jet flows at a constant rate down the observation channel and fluorescence of the protein during folding can be observed using a scanning confocal microscope5.

In this work we explain the fabrication and use of a microfluidic mixer capable of mixing two solutions in ~8 &mu;s. We also demonstrate the use of these mixers with spectroscopic detection using UV fluorescence and fluorescence resonance energy transfer (FRET).

Mikrofluidischen Mischern für ein Studium Proteinfaltung

The process by which a protein folds into its native conformation is highly relevant to biology and human health yet still poorly understood. One reason ...

Correlative Microscopy for 3D Structural Analysis of Dynamic Interactions

Cryo-electron tomography (cryoET) allows 3D visualization of cellular structures at molecular resolution in a close-to-physiological state1. However, direct visualization of individual viral complexes in their host cellular environment with cryoET is challenging2, due to the infrequent and dynamic nature of viral entry, particularly in the case of HIV-1. While time-lapse live-cell imaging has yielded a great deal of information about many aspects of the life cycle of HIV-13-7, the resolution afforded by live-cell microscopy is limited (~ 200 nm). Our work was aimed at developing a correlation method that permits direct visualization of early events of HIV-1 infection by combining live-cell fluorescent light microscopy, cryo-fluorescent microscopy, and cryoET. In this manner, live-cell and cryo-fluorescent signals can be used to accurately guide the sampling in cryoET. Furthermore, structural information obtained from cryoET can be complemented with the dynamic functional data gained through live-cell imaging of fluorescent labeled target.
In this video article, we provide detailed methods and protocols for structural investigation of HIV-1 and host-cell interactions using 3D correlative high-speed live-cell imaging and high-resolution cryoET structural analysis. HeLa cells infected with HIV-1 particles were characterized first by confocal live-cell microscopy, and the region containing the same viral particle was then analyzed by cryo-electron tomography for 3D structural details. The correlation between two sets of imaging data, optical imaging and electron imaging, was achieved using a home-built cryo-fluorescence light microscopy stage. The approach detailed here will be valuable, not only for study of virus-host cell interactions, but also for broader applications in cell biology, such as cell signaling, membrane receptor trafficking, and many other dynamic cellular processes.

We describe a correlative microscopy method that combines high-speed 3D live-cell fluorescent light microscopy and high-resolution cryo-electron tomography. We demonstrate the capability of the correlative method by imaging dynamic, small HIV-1 particles interacting with host HeLa cells.

Korrelative Mikroskopie für 3D-Strukturanalyse von dynamischen Wechselwirkungen

Cryo-electron tomography (cryoET) allows 3D visualization of cellular structures at molecular resolution in a close-to-physiological state1. However, ...

Home-Based Monitor for Gait and Activity Analysis

Current outcomes in neuromuscular disorder clinical trials include motor function scales, timed tests, and strength measures performed by trained clinical evaluators. These measures are slightly subjective and are performed during a visit to a clinic or hospital and constitute therefore a point assessment. Point assessments can be influenced by daily patient condition or factors such as fatigue, motivation, and intercurrent illness. To enable home-based monitoring of gait and activity, a wearable magneto-inertial sensor (WMIS) has been developed. This device is a movement monitor composed of two very light watch-like sensors and a docking station. Each sensor contains a tri-axial accelerometer, gyroscope, magnetometer, and a barometer that record linear acceleration, angular velocity, the magnetic field of the movement in all directions, and barometric altitude, respectively. The sensors can be worn on the wrist, ankle, or wheelchair to record the subject&#8217;s movements during the day. The docking station enables data uploading and recharging of sensor batteries during the night. Data are analyzed using proprietary algorithms to compute parameters representative of the type and intensity of the performed movement. This WMIS can record a set of digital biomarkers, including cumulative variables, such as total number of meters walked, and descriptive gait variables, such as the percentage of the most rapid or longest stride that represents the top performance of patient over a predefined period of time.

This innovative device uses magneto-inertial sensors to permit gait and activity analysis in uncontrolled environments. Currently in the qualification process as an outcome measure in the European Medical Agency, one of the applications will be to serve as a clinical endpoint in clinical trials in neuromuscular diseases.

Home-Based Monitor für Gait- und Aktivitätsanalyse

Current outcomes in neuromuscular disorder clinical trials include motor function scales, timed tests, and strength measures performed by trained clinical ...

Calvarial Model of Bone Augmentation in Rabbit for Assessment of Bone Growth and Neovascularization in Bone Substitution Materials

The basic principle of the rabbit calvarial model is to grow new bone tissue vertically on top of the cortical part of the skull. This model allows assessment of bone substitution materials for oral and craniofacial bone regeneration in terms of bone growth and neovascularization support. Once animals are anesthetized and ventilated (endotracheal intubation), four cylinders made of polyether ether ketone (PEEK) are screwed onto the skull, on both sides of the median and coronal sutures. Five intramedullary holes are drilled within the bone area delimited by each cylinder, allowing influx of bone marrow cells. The material samples are placed into the cylinders which are then closed. Finally, the surgical site is sutured, and animals are awaken. Bone growth may be assessed on live animals by using microtomography. Once animals are euthanized, bone growth and neovascularization may be evaluated by using microtomography, immune-histology and immunofluorescence. As the evaluation of a material requires maximum standardization and calibration, the calvarial model appears ideal. Access is very easy, calibration and standardization are facilitated by the use of defined cylinders and four samples may be assessed simultaneously. Furthermore, live tomography may be used and ultimately a large decrease in animals to be euthanized may be anticipated.

Here we present a surgical protocol in rabbits with the aim to assess bone substitution materials in terms of bone regeneration capacities. By using PEEK cylinders fixed onto rabbit skulls, osteoconduction, osteoinduction, osteogenesis and vasculogenesis induced by the materials may be evaluated either on live or euthanized animals.

Calvarial-Modell der Knochenvergrößerung bei Kaninchen zur Beurteilung des Knochenwachstums und der Neovaskularisation in Knochensubstitutionsmaterialien

The basic principle of the rabbit calvarial model is to grow new bone tissue vertically on top of the cortical part of the skull. This model allows ...

A Human 3D Extracellular Matrix-Adipocyte Culture Model for Studying Matrix-Cell Metabolic Crosstalk

The extracellular matrix (ECM) plays a central role in regulating tissue homeostasis, engaging in crosstalk with cells and regulating multiple aspects of cellular function. The ECM plays a particularly important role in adipose tissue function in obesity, and alterations in adipose tissue ECM deposition and composition are associated with metabolic disease in mice and humans. Tractable in vitro models that permit dissection of the roles of the ECM and cells in contributing to global tissue phenotype are sparse. We describe a novel 3D in vitro model of human ECM-adipocyte culture that permits study of the specific roles of the ECM and adipocytes in regulating adipose tissue metabolic phenotype. Human adipose tissue is decellularized to isolate ECM, which is subsequently repopulated with preadipocytes that are then differentiated within the ECM into mature adipocytes. This method creates ECM-adipocyte constructs that are metabolically active and retain characteristics of the tissues and patients from which they are derived. We have used this system to demonstrate disease-specific ECM-adipocyte crosstalk in human adipose tissue. This culture model provides a tool for dissecting the roles of the ECM and adipocytes in contributing to global adipose tissue metabolic phenotype and permits study of the role of the ECM in regulating adipose tissue homeostasis.

We describe a 3D human extracellular matrix-adipocyte in vitro culture system that permits dissection of the roles of the matrix and adipocytes in contributing to adipose tissue metabolic phenotype.

Ein menschliches 3D extrazelluläres Matrix-Adipozyten-Kulturmodell zum Studium der Matrix-Zell Metabolischen Crosstalk

The extracellular matrix (ECM) plays a central role in regulating tissue homeostasis, engaging in crosstalk with cells and regulating multiple aspects of ...

Controlled Strain of 3D Hydrogels under Live Microscopy Imaging

External forces are an important factor in tissue formation, development, and maintenance. The effects of these forces are often studied using specialized in vitro stretching methods. Various available systems use 2D substrate-based stretchers, while the accessibility of 3D techniques to strain soft hydrogels, is more restricted. Here, we describe a method that allows external stretching of soft hydrogels from their circumference, using an elastic silicone strip as the sample carrier. The stretching system utilized in this protocol is constructed from 3D-printed parts and low-cost electronics, making it simple and easy to replicate in other labs. The experimental process begins with polymerizing thick (&#62;100 &#956;m) soft fibrin hydrogels (Elastic Modulus of ~100 Pa) in a cut-out at the center of a silicone strip. Silicone-gel constructs are then attached to the printed-stretching device and placed on the confocal microscope stage. Under live microscopy the stretching device is activated, and the gels are imaged at various stretch magnitudes. Image processing is then used to quantify the resulting gel deformations, demonstrating relatively homogenous strains and fiber alignment throughout the gel&#8217;s 3D thickness (Z-axis). Advantages of this method include the ability to strain extremely soft hydrogels in 3D while executing in situ microscopy, and the freedom to manipulate the geometry and size of the sample according to the user&#8217;s needs. Additionally, with proper adaptation, this method can be used to stretch other types of hydrogels (e.g., collagen, polyacrylamide or polyethylene glycol) and can allow for analysis of cells and tissue response to external forces under more biomimetic 3D conditions.

The presented method involves uniaxial stretching of 3D soft hydrogels embedded in silicone rubber while allowing live confocal microscopy. Characterization of the external and internal hydrogel strains as well as fiber alignment are demonstrated. The device and protocol developed can assess the response of cells to various strain regimes.

Kontrollierte Dehnung von 3D-Hydrogelen unter Live-Mikroskopie-Bildgebung

External forces are an important factor in tissue formation, development, and maintenance. The effects of these forces are often studied using specialized ...

Measuring 3D In-vivo Shoulder Kinematics using Biplanar Videoradiography

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, multiple ligaments, and approximately 20 muscles. Unfortunately, shoulder pathologies (e.g., rotator cuff tears, joint dislocations, arthritis) are common, resulting in substantial pain, disability, and decreased quality of life. The specific etiology for many of these pathologic conditions is not fully understood, but it is generally accepted that shoulder pathology is often associated with altered joint motion. Unfortunately, measuring shoulder motion with the necessary level of accuracy to investigate motion-based hypotheses is not trivial. However, radiographic-based motion measurement techniques have provided the advancement necessary to investigate motion-based hypotheses and provide a mechanistic understanding of shoulder function. Thus, the purpose of this article is to describe the approaches for measuring shoulder motion using a custom biplanar videoradiography system. The specific objectives of this article are to describe the protocols to acquire biplanar videoradiographic images of the shoulder complex, acquire CT scans, develop 3D bone models, locate anatomical landmarks, track the position and orientation of the humerus, scapula, and torso from the biplanar radiographic images, and calculate the kinematic outcome measures. In addition, the article will describe special considerations unique to the shoulder when measuring joint kinematics using this approach.

Biplane videoradiography can quantify shoulder kinematics with a high degree of accuracy. The protocol described herein was specifically designed to track the scapula, humerus, and the ribs during planar humeral elevation, and outlines the procedures for data collection, processing, and analysis. Unique considerations for data collection are also described.

Messung der 3D-In-vivo-Schulterkinematik mittels biplanarer Videoradiographie

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, ...

Cantilever Bending of Murine Femoral Necks

Fractures in the femoral neck are a common occurrence in individuals with osteoporosis. Many mouse models have been developed to assess disease states and therapies, with biomechanical testing as a primary outcome measure. However, traditional biomechanical testing focuses on torsion or bending tests applied to the midshaft of the long bones. This is not typically the site of high-risk fractures in osteoporotic individuals. Therefore, a biomechanical testing protocol was developed that tests the femoral necks of murine femurs in cantilever bending loading to replicate better the types of fractures experienced by osteoporosis patients. Since the biomechanical outcomes are highly dependent on the flexural loading direction relative to the femoral neck, 3D printed guides were created to maintain a femoral shaft at an angle of 20&#176; relative to the loading direction. The new protocol streamlined the testing by reducing variability in alignment (21.6&#176; &plusmn; 1.5&#176;, COV = 7.1%, n = 20) and improved reproducibility in the measured biomechanical outcomes (average COV = 26.7%). The new approach using the 3D printed guides for reliable specimen alignment improves rigor and reproducibility by reducing the measurement errors due to specimen misalignment, which should minimize sample sizes in mouse studies of osteoporosis.

The present protocol describes the development of a reproducible testing platform for murine femoral necks in a cantilever bending set-up. Custom 3D printed guides were used to consistently and rigidly fix the femurs in optimal alignment.

Cantilever Bending von murinen Oberschenkelhälsen

Fractures in the femoral neck are a common occurrence in individuals with osteoporosis. Many mouse models have been developed to assess disease states and ...

A GMP-Compliant Procedure for the Generation of Gene-Modified T cells

The field of Adoptive Cell Therapy (ACT) has been revolutionized by the development of genetically modified cells, specifically Chimeric Antigen Receptor (CAR)-T cells. These modified cells have shown remarkable clinical responses in patients with hematologic malignancies. However, the high cost of producing these therapies and conducting extensive quality control assessments has limited their accessibility to a broader range of patients. To address this issue, many academic institutions are exploring the feasibility of in-house manufacturing of genetically modified cells, while adhering to guidelines set by national and international regulatory agencies.
Manufacturing genetically modified T cell products on a large scale presents several challenges, particularly in terms of the institution's production capabilities and the need to meet infusion quantity requirements. One major challenge involves producing large-scale viral vectors under Good Manufacturing Practice (GMP) guidelines, which is often outsourced to external companies. Additionally, simplifying the T cell transduction process can help minimize variability between production batches, reduce costs, and facilitate personnel training. In this study, we outline a streamlined process for lentiviral transduction of primary human T cells with a fluorescent marker as the gene of interest. The entire process adheres to GMP-compliant standards and is implemented within our academic institution.

This protocol outlines the process of transducing primary human T cells with a gene of interest, ensuring compatibility with Good Manufacturing Practice (GMP) standards.

Ein GMP-konformes Verfahren zur Erzeugung genmodifizierter T-Zellen

The field of Adoptive Cell Therapy (ACT) has been revolutionized by the development of genetically modified cells, specifically Chimeric Antigen Receptor ...