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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,063 records · Page 59
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

EAP as artificial muscles - progress and challenges

During the last decade and a half new polymers have emerged that respond to electrical stimulation with a significant shape or size change. This capability of electroactive polymer (EAP) materials is attracting the attention of engineers and scientists from many different disciplines.

biomimetics↗
NASA NTRS2004

Biomimetic robots using EAP as artificial muscles - progress and challenges

Biology offers a great model for emulation in areas ranging from tools, computational algorithms, materials science, mechanisms and information technology. In recent years, the field of biomimetics, namely mimicking biology, has blossomed with significant advances enabling the reverse engineering of many animals' functions and implementation of some of these capabilities.

robotics↗
DOE OSTI2019

Skeletal muscle mass as a predictor of the response to neo-adjuvant chemotherapy in locally advanced esophageal cancer

Undernutrition and sarcopenia are associated with a higher incidence of chemotherapy-related toxicity and a poor prognosis in several kinds of cancer, but the impact of sarcopenia on the outcomes of chemotherapy for esophageal cancer remains unclear. Thus, the purpose of this retrospective study was to investigate whether sarcopenia affects the efficacy and toxicities of chemotherapy for advanced esophageal cancer patients. Data were collected from 31 esophageal cancer patients who underwent neo-adjuvant chemotherapy followed by surgery. Body composition was assessed at the start of chemotherapy by bioelectrical impedance analysis, and outcomes of chemotherapy were compared between sarcopenic and non-sarcopenic groups. Of the 31 patients, sarcopenia was observed in 16 (51.6%). The incidence of toxicities was not different between the two groups. However, as for pathologic response, a good therapeutic effect (Grade 2 or higher) was more common in the non-sarcopenic group than in the sarcopenic group (53.3% vs. 25.0%). Multivariate analysis showed that sarcopenia was an independent predictor of poor pathological response (odds ratio 8.02; P = 0.037). The results of this study suggest the potential utility of sarcopenia assessment in neoadjuvant patient selection strategies.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

The multiscale structural and mechanical effects of mouse supraspinatus muscle unloading on the mature enthesis

The musculoskeletal system is sensitive to its loading environment; this is of particular concern under conditions such as disuse, paralysis, and extended-duration space flight. Although structural and mechanical changes to tendon and bone following paralysis and disuse are well understood, there is a pressing need to understand how this unloading affects the bone-tendon interface (enthesis); the location most prone to tears and injury. Here, we therefore elucidated these effects of unloading in the entheses of adult mice shoulders that were paralyzed for 21 days by treatment with botulinum toxin A. Unloading significantly increased the extent of mechanical failure and was associated with structural changes across hierarchical scales. At the millimeter scale, unloading caused bone loss. At the micrometer scale, unloading decreased bioapatite crystal size and crystallographic alignment in the enthesis. At the nanometer scale, unloading induced compositional changes that stiffened the bioapatite/collagen composite tissue. Mathematical modeling and mechanical testing indicated that these factors combined to increase local elevations of stress while decreasing the ability of the tissue to absorb energy prior to failure, thereby increasing injury risk. These first observations of the multiscale effects of unloading on the adult enthesis provide new insight into the hierarchical features of structure and composition that endow the enthesis with increased resistance to failure.

59 BASIC BIOLOGICAL SCIENCES↗