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1.
Gait Posture ; 52: 183-188, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27915222

RESUMEN

Elderly are confronted with reduced physical capabilities and increased metabolic energy cost of walking. Exoskeletons that assist walking have the potential to restore walking capacity by reducing the metabolic cost of walking. However, it is unclear if current exoskeletons can reduce energy cost in elderly. Our goal was to study the effect of an exoskeleton that assists plantarflexion during push-off on the metabolic energy cost of walking in physically active and healthy elderly. Seven elderly (age 69.3±3.5y) walked on treadmill (1.11ms2) with normal shoes and with the exoskeleton both powered (with assistance) and powered-off (without assistance). After 20min of habituation on a prior day and 5min on the test day, subjects were able to walk with the exoskeleton and assistance of the exoskeleton resulted in a reduction in metabolic cost of 12% versus walking with the exoskeleton powered-off. Walking with the exoskeleton was perceived less fatiguing for the muscles compared to normal walking. Assistance resulted in a statistically nonsignificant reduction in metabolic cost of 4% versus walking with normal shoes, likely due to the penalty of wearing the exoskeleton powered-off. Also, exoskeleton mechanical power was relatively low compared to previously identified optimal assistance magnitude in young adults. Future exoskeleton research should focus on further optimizing exoskeleton assistance for specific populations and on considerate integration of exoskeletons in rehabilitation or in daily life. As such, exoskeletons should allow people to walk longer or faster than without assistance and could result in an increase in physical activity and resulting health benefits.


Asunto(s)
Envejecimiento , Articulación del Tobillo/fisiología , Dispositivo Exoesqueleto , Pie/fisiología , Limitación de la Movilidad , Robótica/instrumentación , Anciano , Fenómenos Biomecánicos , Electromiografía , Prueba de Esfuerzo , Femenino , Humanos , Masculino , Rango del Movimiento Articular , Valores de Referencia , Zapatos
2.
Int J Sports Med ; 37(2): 125-33, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26509378

RESUMEN

This study investigated the utility of a 5-min high-intensity exercise protocol (SAFT(5)) to include in prospective cohort studies investigating ACL injury risk. 15 active females were tested on 2 occasions during which their non-dominant leg was analysed before SAFT(5) (PRE), immediately after (POST0), 15 min after (POST15), and 30 min after (POST30). On the first occasion, testing included 5 maximum isokinetic contractions for eccentric and concentric hamstring and concentric quadriceps and on the second occasion, 3 trials of 2 landing tasks (i. e., single-leg hop and drop vertical jump) were conducted. Results showed a reduced eccentric hamstring peak torque at POST0, POST15 and POST30 (p<0.05) and a reduced functional HQ ratio (Hecc/Qcon) at POST15 and POST30 (p<0.05). Additionally, a more extended knee angle at POST30 (p<0.05) and increased knee internal rotation angle at POST0 and POST15 (p<0.05) were found in a single-leg hop. SAFT(5) altered landing strategies associated with increased ACL injury risk and similar to observations from match simulations. Our findings therefore support the utility of a high-intensity exercise protocol such as SAFT(5) to strengthen injury screening tests and to include in prospective cohort studies where time constraints apply.


Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Prueba de Esfuerzo/métodos , Rodilla/fisiología , Fenómenos Biomecánicos , Estudios Transversales , Femenino , Humanos , Traumatismos de la Rodilla/diagnóstico , Traumatismos de la Rodilla/fisiopatología , Contracción Muscular/fisiología , Estudios Prospectivos , Factores de Riesgo , Rotación , Adulto Joven
3.
Science ; 346(6209): 630-1, 2014 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-25359973

RESUMEN

Emerging infectious diseases are reducing biodiversity on a global scale. Recently, the emergence of the chytrid fungus Batrachochytrium salamandrivorans resulted in rapid declines in populations of European fire salamanders. Here, we screened more than 5000 amphibians from across four continents and combined experimental assessment of pathogenicity with phylogenetic methods to estimate the threat that this infection poses to amphibian diversity. Results show that B. salamandrivorans is restricted to, but highly pathogenic for, salamanders and newts (Urodela). The pathogen likely originated and remained in coexistence with a clade of salamander hosts for millions of years in Asia. As a result of globalization and lack of biosecurity, it has recently been introduced into naïve European amphibian populations, where it is currently causing biodiversity loss.


Asunto(s)
Quitridiomicetos , Enfermedades Transmisibles Emergentes/veterinaria , Especies en Peligro de Extinción , Micosis/veterinaria , Urodelos/microbiología , Animales , Biodiversidad , Enfermedades Transmisibles Emergentes/microbiología , Micosis/microbiología , Filogenia , Urodelos/clasificación
4.
Artículo en Inglés | MEDLINE | ID: mdl-18003303

RESUMEN

In order to fit human body, flexibility, or even better stretchability is requested for biomedical systems like implants or smart clothes. A stretchable electronic technology has been developed. This can provide highly stretchable interconnections fully compatible with PCB technologies. In order to prove the feasibility of complex biomedical systems like inner body implants or wearable systems, a variety of stretchable systems has been designed from sensor to power source systems.


Asunto(s)
Biotecnología/instrumentación , Vestuario , Suministros de Energía Eléctrica , Electrónica/instrumentación , Monitoreo Ambulatorio/instrumentación , Telemetría/instrumentación , Transductores , Elasticidad , Diseño de Equipo , Análisis de Falla de Equipo , Monitoreo Ambulatorio/métodos
5.
Artículo en Inglés | MEDLINE | ID: mdl-18003536

RESUMEN

For user comfort reasons, electronic circuits for implantation in the human body or for use as smart clothes should ideally be soft, stretchable and elastic. In this contribution the results of an MID (Molded Interconnect Device) technology will be presented, showing the feasibility of functional stretchable electronic circuits. In the developed technology rigid or flexible standard components are interconnected by meander shaped metallic wires and embedded by molding in a stretchable substrate polymer. Several technologies have been developed to this purpose, which combine low cost and good reliability under mechanical strain. In this way reliable stretchability of the circuits above 100% has been demonstrated. Enhanced reliability has been reached using an additional conductive polymer layer.


Asunto(s)
Materiales Biocompatibles Revestidos , Electrónica , Elastómeros de Silicona , Compuestos de Vinilo , Cobre , Elasticidad , Análisis de Elementos Finitos , Oro , Interacciones Hidrofóbicas e Hidrofílicas , Níquel , Prótesis e Implantes , Estrés Mecánico , Telemetría/instrumentación , Textiles
7.
Science ; 292(5514): 93-5, 2001 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-11292870

RESUMEN

Sixty-five million years ago, massive volcanism produced on the India-Seychelles landmass the largest continental lava deposit (Deccan Traps) of the past 200 million years. Using a molecular clock-independent approach for inferring dating information from molecular phylogenies, we show that multiple lineages of frogs survived Deccan Traps volcanism after millions of years of isolation on drifting India. The collision between the Indian and Eurasian plates was followed by wide dispersal of several of these lineages. This "out-of-India" scenario reveals a zoogeographical pattern that might reconcile paleontological and molecular data in other vertebrate groups.


Asunto(s)
Ecosistema , Filogenia , Ranidae , Erupciones Volcánicas , África , Animales , Asia , Evolución Biológica , Calibración , Europa (Continente) , Fósiles , India , Tiempo
8.
Proc Natl Acad Sci U S A ; 97(12): 6585-90, 2000 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-10841558

RESUMEN

Recent studies have reported that independent adaptive radiations can lead to identical ecomorphs. Our phylogenetic analyses of nuclear and mitochondrial DNA sequences here indicate that a major radiation of ranid frogs on Madagascar produced morphological, physiological, and developmental characters that are remarkably similar to those that independently evolved on the Indian subcontinent. We demonstrate further that, in several cases, adult and larval stages each evolved sets of characters which are not only convergent between independent lineages, but also allowed both developmental stages to invade the same adaptive zone. It is likely that such covariations are produced by similar selective pressures on independent larval and adult characters rather than by genetic or functional linkage. We briefly discuss why larval/adult covariations might constitute an important evolutionary phenomenon in species for which more than one developmental stage potentially has access to multiple environmental conditions.


Asunto(s)
Evolución Biológica , ADN Mitocondrial/química , ADN/química , Ranidae/clasificación , Adaptación Fisiológica , Animales , Secuencia de Bases , Larva , Datos de Secuencia Molecular , Alineación de Secuencia
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