Financiamento das Sociedades Americanas e Internacionais de Biomecânica foi fornecido para este estudo.

<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. 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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>

Os autores declaram que não têm interesses financeiros concorrentes.

Para quantificar as forças conjuntas resultantes e momentos durante o movimento, um modelo de dinâmica inversa do sistema de interesse é necessário quando se trabalha com dados empíricos. Para biomecânica dos membros inferiores, os modelos de dinâmica inversa normalmente representam a pé, pernil, e coxa como corpos rígidos. Entrada para esses modelos vêm de três fontes principais: a) cinemática do movimento, b) força de reação do solo e C) antropométricas segmento e propriedades inerciais. Dados de movimento são recolhidos com uma variedade de sistemas de análise de movimento, mas todos os sistemas essencialmente proporcionar a cinemática básicos do movimento (posição, velocidade e aceleração). Forças de reação do solo são recolhidas com uma plataforma de força e fornecer as forças de contato que agem sobre os pés. Antropometria são medidas tomadas diretamente do corpo usando os governantes, fitas flexíveis e / ou pinças. Estas medições antropométricas são utilizados para estimar as propriedades de inércia dos segmentos corporais utilizados na dynami inversacs analisa. Propriedades de inércia da massa incluem, centro de massa (COM) local e do momento de inércia (MOI) de segmento em relação a um eixo que passa pelo segmento ou COM proximal ou distal comum. Metodologias e equipamentos utilizados para a coleta de dados de movimento e força de reação do solo são semelhantes entre os grupos de pesquisa, mas estimativas inerciais dos segmentos corporais podem variar muito entre os pesquisadores, dependendo de qual método o pesquisador escolhe para estimar essas propriedades inerciais. Várias técnicas disponíveis para estimar as propriedades inerciais de um segmento do corpo humano totalmente intacta incluem: 1) equações de regressão com base em dados de cadáver 1-5, 2) técnicas de modelos matemáticos (ou seja, modelos geométricos) 6,7, e 3) de digitalização e imagem 8-15. Muitas destas técnicas requerem medições directas do corpo, mas que tenha sido previamente demonstrado que, independentemente do método de estimativa a ser usada, a precisão do segmento corporalAs estimativas de inércia mento à base de tais métodos é elevado 16. Também foi mostrado que os erros nas estimativas das propriedades inerciais dos segmentos corporais intactas têm um impacto mínimo sobre as magnitudes dos momentos articulares resultantes durante a caminhada 17,18. Momentos conjuntas são influenciadas em maior medida pelas forças de reação do solo, centro de locais de pressão, comprimentos braço de momento, e cinemática segmento 17-19. Portanto, não é surpreendente que os métodos para estimar propriedades inerciais dos segmentos corporais variam largamente na literatura quando se utiliza indivíduos sãos como participantes da pesquisa, uma vez que pequenos erros nessas estimativas são susceptíveis de ter pouco impacto sobre os resultados do estudo. Muitas dessas estimativas inerciais para um segmento de corpo totalmente intacta são muitas vezes utilizados para estimar as propriedades inerciais das próteses para amputados dos membros inferiores. Próteses dos membros inferiores modernos são fabricados com materiais leves resulting em próteses, que são muito mais leves que os membros que substituem. Isso resulta em uma assimetria de inércia entre a prótese eo membro intacto. Em comparação com uma haste típico intacto e do pé, a massa de uma prótese abaixo do joelho e do membro residual é cerca de 35% menos e tem um centro de massa localizado, aproximadamente, 35% mais estreita que a articulação do joelho 20-23. A menor massa e distribuição de massa mais proximal da prótese também produz uma (~ 60%) muito menor momento de inércia em relação à articulação do joelho para a prótese em comparação com a da haste intacta e pé. Embora os pesquisadores 24,25 já sugeriram que o uso de estimativas inerciais intactas para a prótese ter pouco efeito sobre as estimativas cinéticos conjuntas, estas comparações focada em momentos articulares resultantes durante a fase de apoio do pé, onde a força de reação do solo domina o momento produzido na articulação. Durante swing, onde as forças de reação do solo não estão presentes, oreduzidas propriedades inerciais da prótese são mais propensos a influenciar as estimativas de momentos articulares resultantes. Tendo em conta que alguns pesquisadores, por exemplo, 26-32 utilizam propriedades de inércia segmento intactas para representar prótese propriedades inerciais e outros, por exemplo, 21-23 estimativa prótese propriedades inerciais diretamente, é importante para entender o impacto dos métodos escolhidos para estimar as propriedades inerciais da prótese . Minimizando o tempo necessário para a medição das propriedades de inércia da prótese foi um factor importante no desenvolvimento da nossa técnica. Na técnica apresentada aqui a prótese permanece totalmente intacto para todas as medidas para reduzir os tempos de medição e evitar quaisquer outras vezes, relacionadas ao realinhamento da prótese após a medição. Assim, o objectivo deste estudo era duplo: 1) demonstrar uma técnica que pode ser utilizada directamente para estimar as propriedades de inércia de abelow prótese do joelho, e 2) contrastar os efeitos da técnica proposta e que do uso do membro intacto propriedades inerciais em estimativas cinéticos conjuntas durante a caminhada em unilaterais, amputados transtibiais. Foi sugerido que magnitudes cinéticos conjuntas são maiores quando as propriedades de inércia da haste intacta e pé são usados ​​como as estimativas de inércia para a prótese, em comparação com medições diretas da prótese propriedades inerciais.

<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

O objectivo deste estudo era duplo: 1) demonstrar uma técnica que pode ser utilizada para estimar directamente as propriedades de inércia de uma prótese abaixo do joelho, e 2) os efeitos de contraste da técnica proposta e que o uso de membros intactos propriedades inerciais em estimativas cinéticos conjuntas durante andando em unilaterais, amputados transtibiais. Um sistema de oscilação e tábua de reação foi validado e mostrou-se confiável ao medir propriedades inerciais de sólidos geométricos conhecidos. Quando as medições diretas de propriedades inerciais da prótese foram utilizados na modelagem dinâmica inversa da extremidade mais baixa em comparação com as estimativas de inércia com base em uma haste intacta e pé, cinética articular no quadril e joelho foram significativamente menores durante a fase de balanço da marcha. As diferenças na cinética conjuntas durante postura, no entanto, foram menores do que os observados durante o balanço. Portanto, os pesquisadores com foco na fase de balanço da marcha deve considerar o impacto da prosthesé de propriedade de inércia estimativas sobre os resultados do estudo. Para postura, qualquer um dos dois modelos de inércia investigados em nosso estudo provavelmente levaria a resultados semelhantes com uma avaliação dinâmica inversa.

Propriedades de inércia da distal perna protético para o joelho foram menores do que os da perna intacta (Quadro 1). Média entre os participantes, massa lado prótese foi de 39% menos, momento de inércia em torno de um eixo transversal que passa pelo joelho foi de menos 52%, e a localização do centro de massa foi de 24% para mais perto do joelho em comparação com os valores para a perna intacta. <table border="1" cellpadding="0" cellspacing="0" fo:keep-together.within-page="always" width="553"><tbody><tr><td> Assunto </td><td> Intacta * Massa (kg) </td><td> Prós † Massa (kg) </td><td> Est. Diferença de massa (kg) </td><td> ‡ Iknee intacta (kg · m 2) </td><td> Pros Iknee (kg · m 2) </td><td> CM intacto abaixo da articulação do joelho (m) </td><td> Prós cm abaixo da articulação do joelho (m) </td></tr><tr><td> A </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> A média ± 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 eº 177; 0,022 </td><td> 0,196 ± 0,013 </td></tr></tbody></table> * Intacta refere-se a valores para a haste e pé intacto combinado. † Prós refere-se a valores para a prótese combinada e membro residual. ‡ momento de inércia em torno de um eixo transversal que passa pelo joelho. Tabela 1. Comparação das propriedades inerciais entre as próteses e intactas do joelho para baixo. Forças conjuntas resultantes (Figura 3) e momentos (Figura 4) no tornozelo, joelho e quadril foram afetadas pelos parâmetros inerciais utilizados no modelo de dinâmica inversa. Especificamente, cinética conjuntas foram reduzidos durante o início balanço (~ 65% do ciclo da marcha) e terminação balanço (~ 95% do ciclo da marcha), quando foram utilizadas medidas diretas de inércia prótese na dinâmica inversa avaliações em comparação com regressões com base na anatomia intacta ( <strong&gt; Tabela 2). Os tamanhos de efeito sugerem que estas diferenças durante balanço não eram triviais (≥ 1,0). Além disso, os valores cinéticos conjuntas aumentou em média 80% durante a iniciação e terminação balanço quando foram utilizadas estimativas inerciais intactas em comparação com medidas diretas da prótese propriedades inerciais. Assim, quando as propriedades inerciais de um membro intacto foram usados ​​para modelar o lado protético, perfis cinéticos conjuntos do lado da prótese durante o balanço mais estreitamente se assemelhavam aos de um membro intacto (ver Figuras 3 e 4). Durante postura, observou-se uma série de diferenças estatísticas. O maior tamanho de efeito para qualquer diferença durante postura foi observado para o hip anterioposterior força conjunta resultante (ES = 0,86). Embora este tamanho do efeito é grande e ainda é considerado como parte da postura, o valor de pico para essa medida ocorreu durante apoio terminal (~ 52%), ou como o membro foi a transição para swing. Os tamanhos de efeito para todos os outros significant diferenças observadas durante postura variaram de 0,01 a 0,41, o que seria considerado pequenos efeitos com o maior desses valores sendo observados nas forças de reação articulares do quadril resultantes. Embora foram encontradas diferenças significativas na postura, essas diferenças quando considerados em termos do tamanho da diferença (ou seja, tamanhos de efeito) pode levar alguém a questionar o significado dessas diferenças. <img alt="Figura 3" fo:content-width="5in" src="/files/ftp_upload/50977/50977fig3highres.jpg" width="500" /> Figura 3. Forças de reação conjuntas resultantes do tornozelo, joelho e quadril no anterioposterior (painéis à esquerda) e direções vertical (painéis à direita). Dados foram calculados através de temas para apresentação. A fase de suporte começa a 0% do ciclo de marcha a pé contacto e termina a cerca de 60% do ciclo de marcha de levantamento da biqueira. Balanço continua até o próximo contato do pé de tele mesmo perna a 100% do ciclo da marcha. <a href="https://www.jove.com/files/ftp_upload/50977/50977fig3highres.jpg" target="_blank">Clique aqui para ver uma versão maior desta figura.</a> <img alt="Figura 4" fo:content-width="5in" src="/files/ftp_upload/50977/50977fig4highres.jpg" width="500" /> Figura 4. Momentos conjuntas Resultante torno de um eixo transversal (aka, eixo médio-lateral), através do tornozelo, joelho e quadril. Dados foram calculados através de temas para apresentação. A fase de suporte começa a 0% do ciclo de marcha a pé contacto e termina a cerca de 60% do ciclo de marcha de levantamento da biqueira. Balanço continua até que o próximo contacto do pé da mesma perna a 100% do ciclo de marcha. <img alt="Tabela 2" fo:content-width="6in" src="/files/ftp_upload/50977/50977table2.jpg" width="600" /> Tabela 2. Peak reação conjunta resultanteforças e momentos em média entre os indivíduos e as comparações estatísticas entre os dois modelos de inércia para a cinética conjuntas do lado da prótese Notas:. dados médios são apresentados como média (DP). % Coluna Gait Cycle representa a porcentagem média dos temas em que o valor de pico ocorreu para essa variável. P &lt;0,05 considerado 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

Segmentares Corpo propriedades inerciais são necessários para a modelagem dinâmica inversa. Usando uma oscilação e técnica placa de reação, propriedades inerciais das próteses abaixo do joelho foram medidos. Usando medidas diretas de prótese inércia no modelo de dinâmica inversa da perna protética resultou em magnitudes menores de forças conjuntas resultantes e momentos.

Oscilação e Conselho Reação Técnicas para estimar as propriedades de inércia de uma prótese abaixo do joelho

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 ...

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16.6K visualizações.  University of Northern Colorado.  Segmentares Corpo propriedades inerciais são necessários para a modelagem dinâmica inversa. Usando uma oscilação e técnica placa de reação, propriedades inerciais das próteses abaixo do joelho foram medidos. Usando medidas diretas de prótese inércia no modelo de dinâmica inversa da perna protética resultou em magnitudes menores de forças conjuntas resultantes e momentos. 

Vídeo: 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).

Medir as propriedades mecânicas das células vivas Usando Microscopia de Força Atômica

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

Bioengenharia

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.

Plataforma Engenharia e protocolo experimental para Projeto e Avaliação de um motorizado Transfemoral Prótese controlada pelo Neurally

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.

Em Situ Mapeamento das propriedades mecânicas de biofilmes por de rastreamento de partículas 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.

Técnicas para a Evolução da levedura Pentose-fermentação robusta para bioconversão de transformação de lignocelulose em etanol

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.

Produção de nanopartículas metálicas por ablação a laser pulsada em líquidos: uma ferramenta para estudar as propriedades antibacterianas das nanopartículas

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.

Síntese de hidrogeles com propriedades anti-deposição como membranas de purificação de água

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.

Semiautomated Longitudinal baseados em Microcomputed tomografia computadorizada quantitativa análise estrutural de um modelo de fratura Vertebral relacionadas com osteoporose rato Nude

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.

Um milímetro escala Flexural sistema de testes para medir as propriedades mecânicas de espículas de esponja marinha

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.

Síntese de nanotubos de carbono de paredes Multi modificados com nanopartículas de prata e avaliação das suas actividades antibacterianas e propriedades citotóxicas

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.

Impressão 3D de Microcarriers de hidrogel in vitro alternando jatos de força viscosa-inercial

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 ...