I finanziamenti dalle società americane e internazionali di biomeccanica è stata fornita per questo studio.

<ol>
	<li>Chandler, R. F., Clauser, C. E., McConville, J. T., Reynolds, H. M., Young, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+of+the+inertial+properties+of+the+human+body.">Investigation of the inertial properties of the human body.</a> Pamphlets DOT HS-801 430 and AMRL. , (1975).</li><li>Clauser, C. E., McConville, J. T., Young, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Weight, Volume, and Center of Mass of Segments of the Human Body. AMRL Technical Report. , 60-70 (1969).</li><li>Dempster, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Space+requirements+of+the+seated+operator.">Space requirements of the seated operator.</a> , 55-159 (1955).</li><li>Hinrichs, R. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regression+equations+to+predict+segmental+moments+of+inertia+from+anthropometric+measurements:+an+extension+of+the+data+of+Chandler+et.">Regression equations to predict segmental moments of inertia from anthropometric measurements: an extension of the data of Chandler et.</a> J Biomech. 18, 621-624 (1985).</li><li>Hinrichs, R. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adjustments+to+the+segment+center+of+mass+proportions+of+Clauser+et+al.">Adjustments to the segment center of mass proportions of Clauser et al.</a> J Biomech. 23, 949-951 (1990).</li><li>Hanavan Jr, E. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mathematical+model+of+the+human+body+Amrl-Tr-64-102.">A mathematical model of the human body Amrl-Tr-64-102.</a> AMRL Technical Report. 18, 1-149 (1964).</li><li>Hatze, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mathematical+model+for+the+computational+determination+of+parameter+values+of+anthropomorphic+segments.">A mathematical model for the computational determination of parameter values of anthropomorphic segments.</a> J Biomech. 13, 833-843 (1980).</li><li>Leva, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adjustments+to+Zatsiorsky-Seluyanov's+segment+inertia+parameters.">Adjustments to Zatsiorsky-Seluyanov's segment inertia parameters.</a> J Biomech. 29, 1223-1230 (1996).</li><li>Durkin, J. L., Dowling, 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=Analysis+of+body+segment+parameter+differences+between+four+human+populations+and+the+estimation+errors+of+four+popular+mathematical+models.">Analysis of body segment parameter differences between four human populations and the estimation errors of four popular mathematical models.</a> J Biomech Eng. 125, 515-522 (2003).</li><li>Durkin, J. L., Dowling, J. J., Andrews, 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=The+measurement+of+body+segment+inertial+parameters+using+dual+energy+X-ray+absorptiometry.">The measurement of body segment inertial parameters using dual energy X-ray absorptiometry.</a> J Biomech. 35, 1575-1580 (2002).</li><li>Jensen, R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+the+biomechanical+properties+of+three+body+types+using+a+photogrammetric+method.">Estimation of the biomechanical properties of three body types using a photogrammetric method.</a> J Biomech. 11, 349-358 (1978).</li><li>Martin, P. E., Mungiole, M., Marzke, M. W., Longhill, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+magnetic+resonance+imaging+for+measuring+segment+inertial+properties.">The use of magnetic resonance imaging for measuring segment inertial properties.</a> J Biomech. 22, 367-376 (1989).</li><li>Mungiole, M., Martin, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimating+segment+inertial+properties:+comparison+of+magnetic+resonance+imaging+with+existing+methods.">Estimating segment inertial properties: comparison of magnetic resonance imaging with existing methods.</a> J Biomech. 23, 1039-1046 (1990).</li><li>Zatsiorsky, V. M., Seluyanov, V. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mass+and+inertia+characteristics+of+the+main+segments+of+the+human+body.">The mass and inertia characteristics of the main segments of the human body.</a> Biomechanics VIII-B. , 1152-1159 (1983).</li><li>Zatsiorsky, V. M., Seluyanov, V. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomechanics+IX-B.">Biomechanics IX-B.</a> Human Kinetics. , (1985).</li><li>Challis, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precision+of+the+Estimation+of+Human+Limb+Inertial+Parameters.">Precision of the Estimation of Human Limb Inertial Parameters.</a> Journal of Applied Biomechanics. 15, 418-428 (1999).</li><li>Challis, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+of+Human+Limb+Moment+of+Inertia+Estimations+and+Their+Influence+on+Resultant+Joint+Moments.">Accuracy of Human Limb Moment of Inertia Estimations and Their Influence on Resultant Joint Moments.</a> Journal of Applied Biomechanics. 12, 517-530 (1996).</li><li>Challis, J. H., Kerwin, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+of+the+uncertainties+in+resultant+joint+moments+computed+in+a+dynamic+activity.">Quantification of the uncertainties in resultant joint moments computed in a dynamic activity.</a> J Sports Sci. 14, 219-231 (1996).</li><li>Hunter, J. P., Marshall, R. N., McNair, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Segment-interaction+analysis+of+the+stance+limb+in+sprint+running.">Segment-interaction analysis of the stance limb in sprint running.</a> J Biomech. 37, 1439-1446 (2004).</li><li>Lin-Chan, S. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effects+of+added+prosthetic+mass+on+physiologic+responses+and+stride+frequency+during+multiple+speeds+of+walking+in+persons+with+transtibial+amputation.">The effects of added prosthetic mass on physiologic responses and stride frequency during multiple speeds of walking in persons with transtibial amputation.</a> Arch Phys Med Rehabil. 84, 1865-1871 (2003).</li><li>Mattes, S. J., Martin, P. E., Royer, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Walking+symmetry+and+energy+cost+in+persons+with+unilateral+transtibial+amputations:+matching+prosthetic+and+intact+limb+inertial+properties.">Walking symmetry and energy cost in persons with unilateral transtibial amputations: matching prosthetic and intact limb inertial properties.</a> Arch Phys Med Rehabil. 81, 561-568 (2000).</li><li>Smith, J. D., Martin, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Short+and+longer+term+changes+in+amputee+walking+patterns+due+to+increased+prosthesis+inertia.">Short and longer term changes in amputee walking patterns due to increased prosthesis inertia.</a> J Prosthet Orthot. 23, 114-123 (2011).</li><li>Smith, J. D., Martin, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+prosthetic+mass+distribution+on+metabolic+costs+and+walking+symmetry.">Effects of prosthetic mass distribution on metabolic costs and walking symmetry.</a> J Appl Biomech. 29, 317-328 (2013).</li><li>Czerniecki, J. M., Gitter, A., Munro, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Joint+moment+and+muscle+power+output+characteristics+of+below+knee+amputees+during+running:+the+influence+of+energy+storing+prosthetic+feet.">Joint moment and muscle power output characteristics of below knee amputees during running: the influence of energy storing prosthetic feet.</a> J Biomech. 24, 63-75 (1991).</li><li>Miller, D. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resultant+lower+extremity+joint+moments+in+below-knee+amputees+during+running+stance.">Resultant lower extremity joint moments in below-knee amputees during running stance.</a> J Biomech. 20, 529-541 (1987).</li><li>Vanicek, N., Strike, S., McNaughton, L., Polman, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gait+patterns+in+transtibial+amputee+fallers+vs.+non-fallers:+Biomechanical+differences+during+level+walking.">Gait patterns in transtibial amputee fallers vs. non-fallers: Biomechanical differences during level walking.</a> Gait &amp; Posture. 29, 415-420 (2009).</li><li>Royer, T., Koenig, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Joint+loading+and+bone+mineral+density+in+persons+with+unilateral,+trans-tibial+amputation.">Joint loading and bone mineral density in persons with unilateral, trans-tibial amputation.</a> Clin Biomech. 20, 1119-1125 (2005).</li><li>Underwood, H. A., Tokuno, C. D., Eng, 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=A+comparison+of+two+prosthetic+feet+on+the+multi-joint+and+multi-plane+kinetic+gait+compensations+in+individuals+with+a+unilateral+trans-tibial+amputation.">A comparison of two prosthetic feet on the multi-joint and multi-plane kinetic gait compensations in individuals with a unilateral trans-tibial amputation.</a> Clin Biomech. 19, 609-616 (2004).</li><li>Sjodahl, C., Jarnlo, G. B., Soderberg, B., Persson, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinematic+and+kinetic+gait+analysis+in+the+sagittal+plane+of+trans-femoral+amputees+before+and+after+special+gait+re-education.">Kinematic and kinetic gait analysis in the sagittal plane of trans-femoral amputees before and after special gait re-education.</a> Prosthet Orthot Int. 26, 101-112 (2002).</li><li>Bateni, H., Olney, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinematic+and+kinetic+variations+of+below-knee+amputee+gait.">Kinematic and kinetic variations of below-knee amputee gait.</a> Journal of Prosthetics and Orthotics. 14, 2-12 (2002).</li><li>Buckley, 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=Biomechanical+adaptations+of+transtibial+amputee+sprinting+in+athletes+using+dedicated+prostheses.">Biomechanical adaptations of transtibial amputee sprinting in athletes using dedicated prostheses.</a> Clin Biomech. 15, 352-358 (2000).</li><li>Yack, H. J., Nielsen, D. H., Shurr, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetic+patterns+during+stair+ascent+in+patients+with+transtibial+amputations+using+three+different+prostheses.">Kinetic patterns during stair ascent in patients with transtibial amputations using three different prostheses.</a> Journal of Prosthetics and Orthotics. 11, 57-62 (1999).</li></ol>

Gli autori dichiarano di non avere interessi finanziari in competizione.

Per quantificare le forze congiunte risultanti e momenti durante il movimento, è necessaria una dinamica inversa modello del sistema di interesse quando si lavora con dati empirici. Per biomeccanica degli arti inferiori, modelli di dinamica inversa rappresentano in genere il piede, la zampa, e coscia corpi rigidi. Ingresso per questi modelli provengono da tre fonti principali: a) cinematica del movimento, b) forze di reazione del terreno, e c) antropometria segmento e le proprietà inerziali. Dati di movimento vengono raccolti con una varietà di sistemi di analisi di movimento, ma tutti i sistemi prevedono essenzialmente la cinematica di base del movimento (posizione, velocità e accelerazione). Forze di reazione a terra vengono raccolti con un piatto forza e forniscono le forze di contatto che agiscono sui piedi. Antropometria sono misure prese direttamente dal corpo usando righelli, nastri flessibili, e / o pinze. Queste misurazioni antropometriche sono utilizzati per stimare le proprietà inerziali dei segmenti corporei utilizzati nella dinamicamente inversacs analisi. Proprietà inerziali includono la massa, centro di massa (COM) posizione e momento di inerzia (MOI) del segmento rispetto ad un asse attraverso il COM segmento o prossimale o distale comune. Metodologie e delle attrezzature utilizzate per la raccolta dati di movimento e forza di reazione a terra sono simili tra i gruppi di ricerca, ma stime inerziali dei segmenti corporei può variare notevolmente tra i ricercatori a seconda di quale metodo il ricercatore sceglie per la stima di queste proprietà inerziali. Varie tecniche disponibili per stimare le proprietà inerziali di un segmento corpo umano completamente intatto includono: 1) equazioni di regressione basate su dati di cadavere 1-5, 2) tecniche di modelli matematici (ad esempio, modelli geometrici) 6,7, e 3) scansione e di imaging 8-15. Molte di queste tecniche richiedono misure dirette dal corpo, ma è stato precedentemente dimostrato che, indipendentemente dal metodo di stima utilizzato, la precisione del corpo segstime Ment inerziali basate su questi metodi è alto 16. E &#39;stato anche dimostrato che gli errori nelle stime delle proprietà inerziali dei segmenti corporei intatte hanno un impatto minimo sulle grandezze di momenti comuni risultanti durante la deambulazione 17,18. Momenti comuni sono influenzati in misura maggiore da parte delle forze di reazione di terra, il centro della località di pressione, momento lunghezze del braccio, e cinematica del segmento 17-19. Pertanto, non è sorprendente che i metodi per stimare le proprietà inerziali dei segmenti corporei variano ampiamente attraverso la letteratura quando si utilizzano gli individui normodotati come partecipanti alla ricerca, dato che piccoli errori in queste stime sono suscettibili di avere un impatto sui risultati dello studio. Molte di queste stime inerziali per un segmento del corpo completamente intatto sono spesso usati per stimare le proprietà inerziali di protesi per amputati degli arti inferiori. Le moderne protesi degli arti inferiori sono fabbricati con materiali leggeri resulting in protesi che sono molto più leggeri degli arti che sostituiscono. Ciò si traduce in una asimmetria inerziale tra l&#39;arto protesico e arto intatto. Rispetto ad un tipico gambo intatta e piede, la massa di una protesi sotto il ginocchio e moncone è circa il 35% in meno, un centro di massa situato circa il 35% più vicino al ginocchio 20-23. La massa più bassa e la distribuzione di massa prossimale dell&#39;arto protesico produce anche una molto più bassa (~ 60%) momento d&#39;inerzia rispetto al ginocchio per l&#39;arto protesico rispetto a quello del gambo intatta e piede. Anche se i ricercatori 24,25 hanno già suggerito che utilizzando le stime inerziali intatte per l&#39;arto protesico hanno scarso effetto sulle stime cinetiche comuni, questi confronti sono concentrati sui momenti comuni risultanti durante la fase di appoggio dei piedi, dove la forza di reazione al suolo domina il momento prodotta al giunto. Durante l&#39;oscillazione, dove le forze di reazione del terreno non sono presenti, ilridotti inerzia delle protesi sono più propensi a influenzare le stime di momenti comuni che ne derivano. Dato che alcuni ricercatori ad esempio, 26-32 utilizzano intatte le proprietà del segmento inerzia per rappresentare protesi proprietà inerziali e altri EG 21-23 stima protesi proprietà inerziali direttamente, è importante capire l&#39;impatto dei metodi scelti per stimare le caratteristiche inerziali della protesi . Minimizzando il tempo necessario per la misura inerzia delle protesi è una considerazione importante nello sviluppo della nostra tecnica. Nella tecnica qui presentata la protesi rimane completamente intatto per tutte le misure per ridurre i tempi di misura e di evitare eventuali tempi aggiuntivi connessi con riallineare la protesi dopo la misurazione. Pertanto, lo scopo di questo studio era duplice: 1) dimostrare una tecnica che può essere utilizzata direttamente per stimare le proprietà inerziali di abProtesi elow ginocchio, e 2) contrastare gli effetti della tecnica proposta e quella di utilizzare arto intatto proprietà inerziali su stime cinetiche comuni durante la deambulazione nella unilaterali, amputati transtibiali. È stato ipotizzato che grandezze cinetiche comuni sono più grandi quando le proprietà inerziali del gambo intatta e piede sono utilizzati come le stime inerziali per la protesi rispetto alle misurazioni dirette della protesi proprietà inerziali.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr height="105">
			<td height="105" style="height:105px;width:216px;">Oscillation Rack &#38; Reaction Board</td>
			<td style="width:144px;">Custom Built</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Outer cage made from 80/20 aluminum, inner cage from various thicknesses of solid of aluminum.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Laboratory scale</td>
			<td style="width:144px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">NI LabView</td>
			<td style="width:144px;">National Instruments</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Software for recording TTL pulses from infrared photocell.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">BNC-1050</td>
			<td style="width:144px;">National Instruments</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">BNC Breakout box with direct pin connections to the data acquisition card</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:216px;">MATLAB</td>
			<td style="width:144px;">Mathworks Inc.</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Software for processing oscillation and reaction board data to predict inertial properties of prosthesis.</td>
		</tr>
	</tbody>
</table>

oscillation and reaction board techniques for estimating inertial properties of a below-knee prosthesis

Lo scopo di questo studio è duplice: 1) dimostrare una tecnica che può essere utilizzata per stimare direttamente le proprietà inerziali di una protesi sotto il ginocchio, e 2) contrastare gli effetti della tecnica proposta e quella di utilizzare arto intatto proprietà inerziali su stime cinetiche comuni durante camminare in unilaterali, amputati transtibiali. Un sistema di oscillazione e asse di reazione è stato convalidato e dimostrato di essere affidabile quando si misura inerzia delle note solidi geometrici. Quando misurazioni dirette delle proprietà inerziali della protesi sono stati utilizzati nella dinamica inversa modellazione degli arti inferiori rispetto alle stime inerziali basati su un gambo intatta e piede, cinetica congiunte a livello dell&#39;anca e del ginocchio erano significativamente più bassi durante la fase di oscillazione di camminare. Le differenze nella cinetica comuni durante la presa di posizione, però, erano più piccole di quelle osservate durante l&#39;oscillazione. Pertanto, i ricercatori concentrandosi sulla fase di oscillazione di camminare dovrebbero considerare l&#39;impatto di prosthesè di proprietà di inerzia stime sui risultati dello studio. Per la posizione, sia uno dei due modelli inerziali esaminati nel nostro studio sarebbe probabilmente condurre a risultati simili con una valutazione dinamica inversa.

Inerzia delle distale protesi della gamba al ginocchio erano inferiori a quelli della gamba intatta (Tabella 1). Media di tutti i partecipanti, massa lato protesico era 39% in meno, momento di inerzia attorno ad un asse trasversale attraverso il ginocchio era 52% in meno, e la posizione del centro di massa era del 24% più vicino al ginocchio rispetto ai valori per la gamba intatta. <table border="1" cellpadding="0" cellspacing="0" fo:keep-together.within-page="always" width="553"><tbody><tr><td> Soggetto </td><td> Intatto * Massa (kg) </td><td> Pro † Massa (kg) </td><td> Est. Differenza di massa (kg) </td><td> ‡ Iknee intatto (kg · m 2) </td><td> Pro Iknee (kg · m 2) </td><td> CM intatta sotto del ginocchio (m) </td><td> Pro cm al di sotto del ginocchio (m) </td></tr><tr><td> La </td><td> 6.03 </td><td> 4.27 </td><td> 1.76 </td><td> 0,604 </td><td> 0,325 </td><td> 0,268 </td><td> 0.215 </td></tr><tr><td> B </td><td> 6.07 </td><td> 3.39 </td><td> 2.68 </td><td> 0.400 </td><td> 0.196 </td><td> 0.215 </td><td> 0.177 </td></tr><tr><td> C </td><td> 5.80 </td><td> 3.12 </td><td> 2.68 </td><td> 0.575 </td><td> 0.194 </td><td> 0.264 </td><td> 0.198 </td></tr><tr><td> D </td><td> 5.72 </td><td> 3.17 </td><td> 2.55 </td><td> 0,559 </td><td> 0,317 </td><td> 0.265 </td><td> 0,191 </td></tr><tr><td> E </td><td> 7.14 </td><td> 4.65 </td><td> 2.49 </td><td> 0,742 </td><td> 0,325 </td><td> 0.276 </td><td> 0.200 </td></tr><tr><td> F </td><td> 6.23 </td><td> 4.22 </td><td> 2.01 </td><td> 0.585 </td><td> 0.287 </td><td> 0.260 </td><td> 0.192 </td></tr><tr><td> Media ± STD </td><td> 6.17 ± 0.51 </td><td> 3.80 ± 0.66 </td><td> 2.36 ± 0.38 </td><td> 0,578 ± 0,109 </td><td> 0,274 ± 0,063 </td><td> 0.258 &amp;# 177; 0.022 </td><td> 0.196 ± 0.013 </td></tr></tbody></table> * Intact riferisce ai valori per il gambo intatta combinata e piede. † Pro si riferisce ai valori per la protesi combinata e moncone. ‡ Momento di inerzia attorno ad un asse trasversale attraverso il ginocchio. Tabella 1. Confronto delle proprietà inerziali tra le protesi e intatti dal ginocchio in giù. Risultanti forze congiunte (Figura 3) e momenti (Figura 4) alla caviglia, ginocchio, anca e sono stati influenzati dai parametri inerziali utilizzati nel modello dinamica inversa. In particolare, la cinetica comuni sono stati ridotti durante l&#39;inizio oscillazione (~ 65% del ciclo del passo) e terminazione oscillazione (~ 95% del ciclo del passo), quando sono stati usati misure dirette di inerzia protesi a dinamica inversa valutazioni rispetto a regressioni a base di anatomia intatto ( <strong&gt; Tabella 2). Dimensioni dell&#39;effetto suggeriscono queste differenze durante l&#39;oscillazione non erano banali (≥ 1.0). Inoltre, i valori cinetici comuni aumentati in media del 80% durante l&#39;inizio svolgimento e cessazione in cui sono state utilizzate stime inerziali intatti rispetto alle misure dirette della protesi proprietà inerziali. Così, quando le proprietà inerziali di un arto intatto stati usati per modellare lato protesico, profili cinetici congiunti del lato protesico durante l&#39;oscillazione più strettamente simili a quelle di un arto intatto (vedi figure 3 e 4). Durante l&#39;appoggio, sono stati osservati un certo numero di differenze statistiche. La dimensione più grande effetto per l&#39;eventuale differenza durante l&#39;appoggio è stata osservata per l&#39;anca anterioposterior forza congiunta risultante (ES = 0,86). Anche se questa dimensione dell&#39;effetto è grande e ancora considerato come parte della presa di posizione, il valore di picco per questa misura si è verificato durante l&#39;appoggio terminale (~ 52%), o come l&#39;arto è stato la transizione in altalena. Dimensioni di effetto per tutti gli altri significazionent differenze osservate durante l&#39;appoggio variava 0,01-0,41, che sarebbe considerato piccoli effetti con il più grande di questi valori che vengono osservati nelle forze di reazione dell&#39;articolazione dell&#39;anca che ne derivano. Anche se state riscontrate differenze significative durante l&#39;appoggio, queste differenze se considerate in termini di dimensione della differenza (ad esempio, dimensioni dell&#39;effetto) potrebbero indurre a mettere in discussione la significatività di queste differenze. <img alt="Figura 3" fo:content-width="5in" src="/files/ftp_upload/50977/50977fig3highres.jpg" width="500" /> Figura 3. Risultante forze di reazione congiunte della caviglia, ginocchio e anca in anterioposterior (pannelli a sinistra) e verticale (pannelli a destra). Dati sono stati in media di tutti i soggetti per la presentazione. La fase statica inizia da 0% del ciclo del passo con il contatto del piede e termina a circa il 60% del ciclo del passo con toe-off. Altalena continua fino al prossimo piede contatto di tegli stesso gamba al 100% del ciclo del passo. <a href="https://www.jove.com/files/ftp_upload/50977/50977fig3highres.jpg" target="_blank">Cliccare qui per vedere una versione più grande di questa figura.</a> <img alt="Figura 4" fo:content-width="5in" src="/files/ftp_upload/50977/50977fig4highres.jpg" width="500" /> Figura 4. Momenti comuni Risultante su un asse trasversale (aka, l&#39;asse medio-laterale), attraverso la caviglia, ginocchio e anca. Dati sono stati in media di tutti i soggetti per la presentazione. La fase statica inizia da 0% del ciclo del passo con il contatto del piede e termina a circa il 60% del ciclo del passo con toe-off. Oscillazione continua fino al successivo piede contatto della stessa gamba al 100% del ciclo del passo. <img alt="Tabella 2" fo:content-width="6in" src="/files/ftp_upload/50977/50977table2.jpg" width="600" /> Tabella 2. Peak conseguente reazione comuneforze e momenti in media tra i soggetti e confronti statistici tra i due modelli inerziali per la cinetica comuni del lato protesico. Note: i dati medi sono presentati come media (SD). % Colonna Gait Cycle rappresenta la percentuale media di tutti i soggetti in cui il valore di picco è avvenuto per quella variabile. P &lt;.05 considerato significativo.

Watch this Scientific Journal Video about Oscillation and Reaction Board Techniques for Estimating Inertial Properties of a Below-knee Prosthesis at JoVE.com

Oscillation and Reaction Board Techniques for Estimating Inertial Properties of a Below-knee Prosthesis

Segmentale Corpo proprietà inerziali sono necessari per la modellazione dinamica inversa. Utilizzando un oscillazione e tecnica bordo di reazione, inerzia delle protesi sotto il ginocchio sono stati misurati. Utilizzo di misure dirette di protesi inerzia nella dinamica inversa modello della protesi della gamba comportato minori grandezze delle forze congiunte risultanti e momenti.

Oscillazione e di società di reazione tecniche per stimare inerziale proprietà di una protesi sotto il ginocchio

The purpose of this study was two-fold: 1) demonstrate a technique that can be used to directly estimate the inertial properties of a below-knee ...

oscillation-reaction-board-techniques-for-estimating-inertial

Research

Education

JoVE Journal

JoVE Core

Bioengineering

Physics

Mechanical Engineering

Unit 1

Moment of Inertia

Oscillations

SCIENTISTS IN ACTION

16.6K Views.  University of Northern Colorado.  Segmentale Corpo proprietà inerziali sono necessari per la modellazione dinamica inversa. Utilizzando un oscillazione e tecnica bordo di reazione, inerzia delle protesi sotto il ginocchio sono stati misurati. Utilizzo di misure dirette di protesi inerzia nella dinamica inversa modello della protesi della gamba comportato minori grandezze delle forze congiunte risultanti e momenti. 

Video: Oscillation and Reaction Board Techniques for Estimating Inertial Properties of a Below-knee Prosthesis

Measuring the Mechanical Properties of Living Cells Using Atomic Force Microscopy

Mechanical properties of cells and extracellular matrix (ECM) play important roles in many biological processes including stem cell differentiation, tumor formation, and wound healing. Changes in stiffness of cells and ECM are often signs of changes in cell physiology or diseases in tissues. Hence, cell stiffness is an index to evaluate the status of cell cultures. Among the multitude of methods applied to measure the stiffness of cells and tissues, micro-indentation using an Atomic Force Microscope (AFM) provides a way to reliably measure the stiffness of living cells. This method has been widely applied to characterize the micro-scale stiffness for a variety of materials ranging from metal surfaces to soft biological tissues and cells. The basic principle of this method is to indent a cell with an AFM tip of selected geometry and measure the applied force from the bending of the AFM cantilever. Fitting the force-indentation curve to the Hertz model for the corresponding tip geometry can give quantitative measurements of material stiffness. This paper demonstrates the procedure to characterize the stiffness of living cells using AFM. Key steps including the process of AFM calibration, force-curve acquisition, and data analysis using a MATLAB routine are demonstrated. Limitations of this method are also discussed.

This paper demonstrates a protocol to characterize the mechanical properties of living cells by means of microindentation using an Atomic Force Microscope (AFM).

Misurare le proprietà meccaniche del Living cellule utilizzando microscopia a forza atomica

Mechanical  properties of cells and extracellular matrix (ECM) play important roles in many  biological processes including stem cell differentiation, ...

Ricerca

Bioingegneria

Engineering Platform and Experimental Protocol for Design and Evaluation of a Neurally-controlled Powered Transfemoral Prosthesis

To enable intuitive operation of powered artificial legs, an interface between user and prosthesis that can recognize the user's movement intent is desired. A novel neural-machine interface (NMI) based on neuromuscular-mechanical fusion developed in our previous study has demonstrated a great potential to accurately identify the intended movement of transfemoral amputees. However, this interface has not yet been integrated with a powered prosthetic leg for true neural control. This study aimed to report (1) a flexible platform to implement and optimize neural control of powered lower limb prosthesis and (2) an experimental setup and protocol to evaluate neural prosthesis control on patients with lower limb amputations. First a platform based on a PC and a visual programming environment were developed to implement the prosthesis control algorithms, including NMI training algorithm, NMI online testing algorithm, and intrinsic control algorithm. To demonstrate the function of this platform, in this study the NMI based on neuromuscular-mechanical fusion was hierarchically integrated with intrinsic control of a prototypical transfemoral prosthesis. One patient with a unilateral transfemoral amputation was recruited to evaluate our implemented neural controller when performing activities, such as standing, level-ground walking, ramp ascent, and ramp descent continuously in the laboratory. A novel experimental setup and protocol were developed in order to test the new prosthesis control safely and efficiently. The presented proof-of-concept platform and experimental setup and protocol could aid the future development and application of neurally-controlled powered artificial legs.

Neural-machine interfaces (NMI) have been developed to identify the user's locomotion mode. These NMIs are potentially useful for neural control of powered artificial legs, but have not been fully demonstrated. This paper presented (1) our designed engineering platform for easy implementation and development of neural control for powered lower limb prostheses and (2) an experimental setup and protocol in a laboratory environment to evaluate neurally-controlled artificial legs on patients with lower limb amputations safely and efficiently.

Ingegneria della piattaforma e protocollo sperimentale per la progettazione e la valutazione di un Powered transfemorale protesi neurale controllata

To enable intuitive operation of powered artificial legs, an interface between user and prosthesis that can recognize the user's movement intent is ...

In Situ Mapping of the Mechanical Properties of Biofilms by Particle-tracking Microrheology

Bacterial cells are able to form surface-attached biofilm communities known as biofilms by encasing themselves in extracellular polymeric substances (EPS). The EPS serves as a physical and protective scaffold that houses the bacterial cells and consists of a variety of materials that includes proteins, exopolysaccharides and DNA. The composition of the EPS may change, which remodels the mechanic properties of the biofilm to further develop or support alternative biofilm structures, such as streamers, as a response to environmental cues. Despite this, there are little quantitative descriptions on how EPS components contribute to the mechanical properties and function of biofilms. Rheology, the study of the flow of matter, is of particular relevance to biofilms as many biofilms grow in flow conditions and are constantly exposed to shear stress. It also provides measurement and insight on the spreading of the biofilm on a surface. Here, particle-tracking microrheology is used to examine the viscoelasticity and effective crosslinking roles of different matrix components in various parts of the biofilm during development. This approach allows researchers to measure mechanic properties of biofilms at the micro-scale, which might provide useful information for controlling and engineering biofilms.

In Situ Mapping of the Mechanical Properties of Biofilms by Particle-tracking Microrheology

Particle-tracking microrheology investigates the viscoelasticity of materials. Here, the technique is used to determine the viscoelasticity, creep compliance and effective crosslinking roles of different matrix components of a bacterial biofilm. The matrix consists of polymeric substances secreted by the bacteria and its components determine biofilm structure and mechanical properties.

In Situ mappatura delle proprietà meccaniche del biofilm da-Particle tracciamento Microrheology

Bacterial cells are able to form surface-attached biofilm communities known as biofilms by encasing themselves in extracellular polymeric substances ...

Techniques for the Evolution of Robust Pentose-fermenting Yeast for Bioconversion of Lignocellulose to Ethanol

Lignocellulosic biomass is an abundant, renewable feedstock useful for production of fuel-grade ethanol and other bio-products. Pretreatment and enzyme saccharification processes release sugars that can be fermented by yeast. Traditional industrial yeasts do not ferment xylose (comprising up to 40% of plant sugars) and are not able to function in concentrated hydrolyzates. Concentrated hydrolyzates are needed to support economical ethanol recovery, but they are laden with toxic byproducts generated during pretreatment. While detoxification methods can render hydrolyzates fermentable, they are costly and generate waste disposal liabilities. Here, adaptive evolution and isolation techniques are described and demonstrated to yield derivatives of the native Scheffersomyces stipitis strain NRRL Y-7124 that are able to efficiently convert hydrolyzates to economically recoverable ethanol despite adverse culture conditions. Improved individuals are enriched in an evolving population using multiple selection pressures reliant on natural genetic diversity of the S. stipitis population and mutations induced by exposures to two diverse hydrolyzates, ethanol or UV radiation. Final evolution cultures are dilution plated to harvest predominant isolates, while intermediate populations, frozen in glycerol at various stages of evolution, are enriched on selective media using appropriate stress gradients to recover most promising isolates through dilution plating. Isolates are screened on various hydrolyzate types and ranked using a novel procedure involving dimensionless relative performance index (RPI) transformations of the xylose uptake rate and ethanol yield data. Using the RPI statistical parameter, an overall relative performance average is calculated to rank isolates based on multiple factors, including culture conditions (varying in nutrients and inhibitors) and kinetic characteristics. Through application of these techniques, derivatives of the parent strain had the following improved features in enzyme saccharified hydrolyzates at pH 5-6: reduced initial lag phase preceding growth, reduced diauxic lag during glucose-xylose transition, significantly enhanced fermentation rates, improved ethanol tolerance and accumulation to 40 g/L.

Adaptive evolution and isolation techniques are described and demonstrated to yield derivatives of Scheffersomyces stipitis strain NRRL Y-7124 that are able to rapidly consume hexose and pentose mixed sugars in enzyme saccharified undetoxified hydrolyzates and to accumulate over 40 g/L ethanol.

Tecniche per l&#39;evoluzione della robusta lievito Pentoso-fermentazione per bioconversione della lignocellulosa a etanolo

Lignocellulosic biomass is an abundant, renewable feedstock useful for production of fuel-grade ethanol and other bio-products. Pretreatment and enzyme ...

Production of Metal Nanoparticles by Pulsed Laser-ablation in Liquids: A Tool for Studying the Antibacterial Properties of Nanoparticles

The emergence of multidrug-resistant bacteria is a global clinical concern leading some to speculate about our return to a "pre-antibiotics" era of medicine. In addition to efforts to identify novel small-molecule antimicrobial drugs, there has been great interest in the use of metal nanoparticles as coatings for medical devices, wound dressings, and consumer packaging, due to their antimicrobial properties. The wide variety of methods available for nanoparticle synthesis results in a broad spectrum of chemical and physical properties which can affect antibacterial efficacy. This manuscript describes the pulsed laser-ablation in liquids (PLAL) method to create nanoparticles. This approach allows for the fine tuning of nanoparticle size, composition, and stability using post-irradiation methods as well as the addition of surfactants or volume excluders. By controlling particle size and composition, a large range of physical and chemical properties of metal nanoparticles can be explored which may contribute to their antimicrobial efficacy thereby opening new avenues for antibacterial development.

The antimicrobial properties of metals such as copper and silver have been recognized for centuries. This protocol describes pulsed laser-ablation in liquids, a method of synthesizing metal nanoparticles that provides the ability to fine tune the properties of these nanoparticles to optimize their antimicrobial effects.

Produzione di nanoparticelle metalliche mediante ablazione laser pulsata nei liquidi: uno strumento per studiare le proprietà antibatteriche delle nanoparticelle

The emergence of multidrug-resistant bacteria is a global clinical concern leading some to speculate about our return to a "pre-antibiotics" era of ...

Synthesis of Hydrogels with Antifouling Properties As Membranes for Water Purification

Hydrogels have been widely utilized to enhance the surface hydrophilicity of membranes for water purification, increasing the antifouling properties and thus achieving stable water permeability through membranes over time. Here, we report a facile method to prepare hydrogels based on zwitterions for membrane applications. Freestanding films can be prepared from sulfobetaine methacrylate (SBMA) with a crosslinker of poly(ethylene glycol) diacrylate (PEGDA) via photopolymerization. The hydrogels can also be prepared by impregnation into hydrophobic porous supports to enhance the mechanical strength. These films can be characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to determine the degree of conversion of the (meth)acrylate groups, using goniometers for hydrophilicity and differential scanning calorimetry (DSC) for polymer chain dynamics. We also report protocols to determine the water permeability in dead-end filtration systems and the effect of foulants (bovine serum albumin, BSA) on membrane performance.

This paper reports practical methods to prepare hydrogels in freestanding films and impregnated membranes and to characterize their physical properties, including water transport properties.

Sintesi di idrogel con proprietà antivegetative come membrane per la purificazione dell&#39;acqua

Hydrogels have been widely utilized to enhance the surface hydrophilicity of membranes for water purification, increasing the antifouling properties and ...

Semiautomated Longitudinal Microcomputed Tomography-based Quantitative Structural Analysis of a Nude Rat Osteoporosis-related Vertebral Fracture Model

Osteoporosis-related vertebral compression fractures (OVCFs) are a common and clinically unmet need with increasing prevalence as the world population ages. Animal OVCF models are essential to the preclinical development of translational tissue engineering strategies. While a number of models currently exist, this protocol describes an optimized method for inducing multiple highly reproducible vertebral defects in a single nude rat. A novel longitudinal semiautomated microcomputed tomography (&#181;CT)-based quantitative structural analysis of the vertebral defects is also detailed. Briefly, rats were imaged at multiple time points post-op. The day 1 scan was reoriented to a standard position, and a standard volume of interest was defined. Subsequent &#181;CT scans of each rat were automatically registered to the day 1 scan so the same volume of interest was then analyzed to assess for new bone formation. This versatile approach can be adapted to a variety of other models where longitudinal imaging-based analysis could benefit from precise 3D semiautomated alignment. Taken together, this protocol describes a readily quantifiable and easily reproducible system for osteoporosis and bone research. The suggested protocol takes 4 months to induce osteoporosis in nude ovariectomized rats and between 2.7 and 4 h to generate, image, and analyze two vertebral defects, depending on tissue size and equipment.

The goal of this protocol is to generate a nude rat osteoporosis-related vertebral compression fracture model that can be longitudinally evaluated in vivo using a semiautomated microcomputed tomography-based quantitative structural analysis.

Semiautomatica longitudinale basati su Microcomputed tomografia quantitativa analisi strutturale di un modello di relazione con l'osteoporosi fratture vertebrali del ratto nudo

Osteoporosis-related vertebral compression fractures (OVCFs) are a common and clinically unmet need with increasing prevalence as the world population ...

A Millimeter Scale Flexural Testing System for Measuring the Mechanical Properties of Marine Sponge Spicules

Many load bearing biological structures (LBBSs)&#8212;such as feather rachises and spicules&#8212;are small (&#60;1 mm) but not microscopic. Measuring the flexural behavior of these LBBSs is important for understanding the origins of their remarkable mechanical functions.
We describe a protocol for performing three-point bending tests using a custom-built mechanical testing device that can measure forces ranging from 10-5 to 101 N and displacements ranging from 10-7 to 10-2 m. The primary advantage of this mechanical testing device is that the force and displacement capacities can be easily adjusted for different LBBSs. The device&#39;s operating principle is similar to that of an atomic force microscope. Namely, force is applied to the LBBS by a load point that is attached to the end of a cantilever. The load point displacement is measured by a fiber optic displacement sensor and converted into a force using the measured cantilever stiffness. The device&#39;s force range can be adjusted by using cantilevers of different stiffnesses.
The device&#39;s capabilities are demonstrated by performing three-point bending tests on the skeletal elements of the marine sponge Euplectella aspergillum. The skeletal elements&#8212;known as spicules&#8212;are silica fibers that are approximately 50 &#181;m in diameter. We describe the procedures for calibrating the mechanical testing device, mounting the spicules on a three-point bending fixture with a &#8776;1.3 mm span, and performing a bending test. The force applied to the spicule and its deflection at the location of the applied force are measured.

We present a protocol for performing three-point bending tests on sub-millimeter scale fibers using a custom-built mechanical testing device. The device can measure forces ranging from 20 &#181;N up to 10 N and can therefore accommodate a variety of fiber sizes.

Un sistema di prova millimetro scala flessionale per misurare le proprietà meccaniche di spicole di spugna marina

Many load bearing biological structures (LBBSs)&#8212;such as feather rachises and spicules&#8212;are small (&#60;1 mm) but not microscopic. Measuring the ...

Synthesis of Multi-walled Carbon Nanotubes Modified with Silver Nanoparticles and Evaluation of Their Antibacterial Activities and Cytotoxic Properties

In this study, multi-walled carbon nanotubes (MWCNTs) were treated with an aqueous sulfuric acid solution to form an oxygen-based functional group. Silver MWCNTs were prepared by the reductive deposition of silver from an aqueous solution of AgNO3 on the oxidized MWCNTs. Given the unique color of the CNTs, it was not possible to apply them to the minimum inhibitory concentration or mitochondrial toxicity assays to evaluate the toxicity and antibacterial properties, since they would interfere with the assays. The inhibition zone and minimum bactericidal concentration for the Ag-MWCNTs were measured and Live/Dead and Trypan Blue assays were used to measure the toxicity and antibacterial properties without interfering with the color of the CNTs.

In this study, antimicrobial nanomaterials were synthesized by acidic oxidation of multiwalled carbon nanotubes and subsequent reductive deposition of silver nanoparticles. Antimicrobial activity and cytotoxicity tests were performed with the as-prepared nanomaterials.

Sintesi di nanotubi di carbonio Multi-parete modificati con nanoparticelle di argento e valutazione dell'attività antibatterica e proprietà citotossiche

In this study, multi-walled carbon nanotubes (MWCNTs) were treated with an aqueous sulfuric acid solution to form an oxygen-based functional group. Silver ...

3D Printing of In Vitro Hydrogel Microcarriers by Alternating Viscous-Inertial Force Jetting

Microcarriers are beads with a diameter of 60-250 &#181;m and a large specific surface area, which are commonly used as carriers for large-scale cell cultures. Microcarrier culture technology has become one of the main techniques in cytological research and is commonly used in the field of large-scale cell expansion. Microcarriers have also been shown to play an increasingly important role in in vitro tissue engineering construction and clinical drug screening. Current methods for preparing microcarriers include microfluidic chips and inkjet printing, which often rely on complex flow channel design, an incompatible two-phase interface, and a fixed nozzle shape. These methods face the challenges of complex nozzle processing, inconvenient nozzle changes, and excessive extrusion forces when applied to multiple bioink. In this study, a 3D printing technique, called alternating viscous-inertial force jetting, was applied to enable the construction of hydrogel microcarriers with a diameter of 100-300 &#181;m. Cells were subsequently seeded on microcarriers to form tissue engineering modules. Compared to existing methods, this method offers a free nozzle tip diameter, flexible nozzle switching, free control of printing parameters, and mild printing conditions for a wide range of bioactive materials.

3D Printing of In Vitro Hydrogel Microcarriers by Alternating Viscous-Inertial Force Jetting

Presented here is a mild 3D printing technique driven by alternating viscous-inertial forces to enable the construction of hydrogel microcarriers. Homemade nozzles offer flexibility, allowing easy replacement for different materials and diameters. Cell binding microcarriers with a diameter of 50-500 &#181;m can be obtained and collected for further culturing.

Stampa 3D di microcarrier idrogel in vitro mediante getto alternato di forza viscosa-inerziale

Microcarriers are beads with a diameter of 60-250 &#181;m and a large specific surface area, which are commonly used as carriers for large-scale cell ...