| 1. |
- Singh Rupal, Baltej, et al.
(författare)
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Lower-limb exoskeletons : Research trends and regulatory guidelines in medical and non-medical applications
- 2017
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Ingår i: International Journal of Advanced Robotic Systems. - : Sage Publications. - 1729-8806 .- 1729-8814. ; 14:6, s. 1-27
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Forskningsöversikt (refereegranskat)abstract
- With the recent progress in personal care robots, interest in wearable exoskeletons has been increasing due to the demand for assistive technologies generally and specifically to meet the concerns in the increasing ageing society. Despite this global trend, research focus has been on load augmentation for soldiers/workers, assisting trauma patients, paraplegics, spinal cord injured persons and for rehabilitation purposes. Barring the military-focused activities, most of the work to date has focused on medical applications. However, there is a need to shift attention towards the growing needs of elderly people, that is, by realizing assistive exoskeletons that can help them to stay independent and maintain a good quality of life. Therefore, the present article covers the rapidly evolving area of wearable exoskeletons in a holistic manner, for both medical and non-medical applications, so that relevant current developments and future issues can be addressed; this includes how the physical assistance/rehabilitation/compensation can be provided to supplement capabilities in a natural manner. Regulatory guidelines, important for realizing new markets for these emerging technologies, are also explored in this work. For these, emerging international safety requirements are presented for non-medical and medical exoskeleton applications, so that the central requirement of close human–robot interactions can be adequately addressed for the intended tasks to be carried out. An example case study on developing and commercializing wearable exoskeletons to help support living activities of healthy elderly persons is presented to highlight the main issues in non-medical mobility exoskeletons. This also paves the way for the potential future trends to use exoskeletons as physical assistant robots, as covered by the recently published safety standard ISO 13482, to help elderly people perform their activities of daily living.
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| 2. |
- Andersson, Mikael Svante, et al.
(författare)
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Magnetic properties of nanoparticle compacts with controlled broadening of the particle size distribution
- 2017
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Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 95:18
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Tidskriftsartikel (refereegranskat)abstract
- Binary random compacts with different proportions of small (volume V) and large (volume 2V) essentially bare maghemite nanoparticles are used to investigate the effect of controllably broadening the particle size distribution on the magnetic properties of magnetic nanoparticle assemblies with strong dipolar interaction. A series of eight random mixtures of highly uniform 9.0- and 11.5-nm-diameter maghemite particles prepared by thermal decomposition is studied. In spite of the severely broadened size distributions in the mixed samples, well-defined superspin glass transition temperatures are observed across the series, their values increasing linearly with the weight fraction of large particles.
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| 3. |
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| 4. |
- Andersson, Mikael Svante, et al.
(författare)
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Particle size-dependent superspin glass behavior in random compacts of monodisperse maghemite nanoparticles
- 2016
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Ingår i: Materials Research Express. - : IOP Publishing. - 2053-1591. ; 3:4
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Tidskriftsartikel (refereegranskat)abstract
- Dense random assemblies made from highly monodisperse gamma-Fe2O3 nanoparticles with sizes ranging from 6.2 to 11.5 nm have been investigated by DC and AC magnetometry. It is found that all assemblies undergo superspin glass phase transitions. The superspin glass phase transition temperature is strongly dependent on the particle size and the nature of the interparticle interaction. However the transition from superparamagnet to superspin glass, as evidenced by the shape of the ac-susceptibility curves and the dynamic critical exponents associated with the transition, is similar in all systems.
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| 5. |
- Andersson, Mikael Svante, et al.
(författare)
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Size-dependent surface effects in maghemite nanoparticles and its impact on interparticle interactions in dense assemblies
- 2015
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 26:47
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Tidskriftsartikel (refereegranskat)abstract
- The question of the dominant interparticle magnetic interaction type in random closely packed assemblies of different diameter (6.2-11.5 nm) bare maghemite nanoparticles (NPs) is addressed. Single-particle magnetic properties such as particle anisotropy and exchange bias field are first of all studied in dilute (reference) systems of these same NPs, where interparticle interactions are neglible. Substantial surface spin disorder is revealed in all particles except the smallest, viz. for diameters d = 8-11.5 nm but not for d = 6.2-6.3 nm. X-ray diffraction analysis points to a crystallographic origin of this effect. The study of closely packed assemblies of the d >= 8 nm particles observes collective (superspin) freezing that clearly appears to be governed by interparticle dipole interactions. However, the dense assemblies of the smallest particles exhibit freezing temperatures that are higher than expected from a simple (dipole) extrapolation of the corresponding temperatures found in the d >= 8 nm assemblies. It is suggested that the nature of the dominant interparticle interaction in these smaller particle assemblies is superexchange, whereby the lack of significant surface spin disorder allows this mechanism to become important at the level of interacting superspins.
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| 6. |
- Bandyopadhyay, Sulalit, et al.
(författare)
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Growing gold nanostructures for shape-selective cellular uptake
- 2018
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Ingår i: Nanoscale Research Letters. - : SpringerOpen. - 1931-7573 .- 1556-276X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- With development in the synthesis of shape- and size-dependent gold (Au) nanostructures (NSs) and their applications in nanomedicine, one of the biggest challenges is to understand the interaction of these shapes with cancer cells. Herein, we study the interaction of Au NSs of five different shapes with glioblastoma-astrocytoma cells. Three different shapes (nanorods, tetrahexahedra, and bipyramids), possessing tunable optical properties, have been synthesized by a single-step seed-mediated growth approach employing binary surfactant mixtures of CTAB and a secondary surfactant By the use of two-step seed-mediated approach, we obtained new NSs, named nanomakura (Makura is a Japanese word used for pillow) which is reported for the first time here. Spherical Au nanoparticles were prepared by the Turkevich method. To study NS-cell interactions, we functionalized the NSs using thiolated PEG followed by 11-Mercaptoundecanoic acid. The influence of shape and concentration of NSs on the cytotoxicity were assessed with a LIVE/DEAD assay in glioblastoma-astrocytoma cells. Furthermore, the time-dependent uptake of nanomakura was studied with TEM. Our results indicate that unlike the other shapes studied here, the nanomakura were taken up both via receptor-mediated endocytosis and macropinocytosis. Thus, from our library of different NSs with similar surface functionality, the shape is found to be an important parameter for cellular uptake.
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| 7. |
- Christensen, Simon, et al.
(författare)
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AXO-SUIT : A Modular Full-Body Exoskeleton for Physical Assistance
- 2019
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Ingår i: Mechanism Design for Robotics. - Cham : Springer Netherlands. - 9783030003647 - 9783030003654 ; , s. 443-450
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Bokkapitel (refereegranskat)abstract
- This paper presents the design of a modular full-body assistive exoskeleton (FB-AXO) for older adults which was developed with funding under the AAL funded AXO-SUIT project. Processes used to formulate a prioritized set of functional and design requirements via close-end-user involvement are outlined and used in realizing the exoskeleton. Design of the resulting mechanics and electronics details for the lower and upper-body subsystems (LB-AXO and (UB-AXO)) are described. Innovative designs of shoulder and spine mechanisms are presented. TheFB-AXO system comprises 27 degrees of freedom, of which 17 are passive and 10 active. The exoskeleton assists full-body motions such as walking, standing, bending, as well as performing lifting and carrying tasks to assist older users performing tasks of daily living.
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| 8. |
- Gamelas, José A. F., et al.
(författare)
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On the morphology of cellulose nanofibrils obtained by TEMPO-mediated oxidation and mechanical treatment
- 2015
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Ingår i: Micron. - : Elsevier BV. - 0968-4328 .- 1878-4291. ; 72, s. 28-33
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Tidskriftsartikel (refereegranskat)abstract
- The morphological properties of cellulose nanofibrils obtained from eucalyptus pulp fibres were assessed. Two samples were produced with the same chemical treatment (NaClO/NaBr/TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) oxidation), but distinct mechanical treatment intensities during homogenization. It was shown that the nanofibrils production yield increases with the mechanical energy. The effect of mechanical treatment on the yield was confirmed by laser profilometry of air-dried nanocellulose films. However, no significant differences were detected regarding the nanofibrils width as measured by atomic force microscopy (AFM) of air-dried films. On the other hand, differences in size were found either by laser diffraction spectroscopy or by dynamic light scattering (DLS) of the cellulose nanofibrils suspensions as a consequence of the differences in the length distribution of both samples. The nanofibrils length of the more nanofibrillated sample was calculated based on the width measured by AFM and the hydrodynamic diameter obtained by DLS. A length value of ca. 600. nm was estimated. The DLS hydrodynamic diameter, as an equivalent spherical diameter, was used to estimate the nanofibrils length assuming a cylinder with the same volume and with the diameter (width) assessed by AFM. A simple method is thus proposed to evaluate the cellulose nanofibrils length combining microscopy and light scattering methods.
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| 9. |
- Haider, Usman, et al.
(författare)
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Modular Exo-Legs For Mobility Of Elderly Persons
- 2016
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Ingår i: Advances in Cooperative Robotics. - Singapore : WORLD SCIENTIFIC. - 9789813149120 - 9789813149144 ; , s. 851-859
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The paper presents details of the AAL Call 4 EXO-LEGS project aimed at developing and testing lower body assistive exoskeletons to help elderly persons perform daily living activities independently such as stable standing, sit-to-stand transfers, and straight walking. The key components needed have been realized using mobility requirements and design preferences provided by an end-user group comprising 117 members via 5 surveys. Modular human-centric concepts are followed for mechanical design, sensing, and actuation, system integration, etc., to realize a BASIC exoskeleton prototype able to provide up to 30% power to assist the human perform the intended motions. Two ethical approvals have been obtained to involve end-users in the research, development, and test phases of the project. To date, 5 test subjects have tested the exoskeleton prototype in walking and sit-to-stand test; summary results are presented in this paper
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| 10. |
- McDonagh, Birgitte H, et al.
(författare)
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Controlling the self-assembly and optical properties of gold nanoclusters and gold nanoparticles biomineralized with bovine serum albumin
- 2015
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 5:122, s. 101101-101109
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Tidskriftsartikel (refereegranskat)abstract
- While the size-dependent optical properties of BSA-stabilized gold nanoclusters are well known, the timedependent growth mechanism remains to be described. Herein, we systematically compare two synthesis methods with and without ascorbic acid, and show that tuning of BSA-stabilized gold nanoclusters (AuNCs) of different sizes can be performed without the aid of an extrinsic reducing agent and with good reproducibility. We also show that adding ascorbic acid yields larger BSA-stabilized gold nanoparticles (AuNPs), and that AuNPs can only form above a threshold gold precursor concentration. Using computed tomography, we describe how these biomineralized AuNPs show size-dependent X-ray attenuation. Growth of BSA-stabilized AuNCs and AuNPs, over a range of gold precursor concentrations, was followed with steady-state fluorescence and UV-vis spectroscopy for one week, constituting the first study of its kind. Based on our results, we propose a mechanism for BSA-stabilization of AuNCs and AuNPs that can further aid in selective growth of discrete AuNCs and AuNPs.
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