| 1. |
- Volpe, Giovanni, 1979, et al.
(author)
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Roadmap for optical tweezers
- 2023
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In: Journal of Physics-Photonics. - : IOP Publishing. - 2515-7647. ; 5:2
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Journal article (peer-reviewed)abstract
- Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation of objects, ranging from atoms to space light sails. Since the pioneering work by Arthur Ashkin in the 1970s, optical tweezers have evolved into sophisticated instruments and have been employed in a broad range of applications in the life sciences, physics, and engineering. These include accurate force and torque measurement at the femtonewton level, microrheology of complex fluids, single micro- and nano-particle spectroscopy, single-cell analysis, and statistical-physics experiments. This roadmap provides insights into current investigations involving optical forces and optical tweezers from their theoretical foundations to designs and setups. It also offers perspectives for applications to a wide range of research fields, from biophysics to space exploration.
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| 2. |
- Gillibert, R., et al.
(author)
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Raman tweezers for tire and road wear micro- and nanoparticles analysis
- 2022
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In: Environmental Science-Nano. - : Royal Society of Chemistry (RSC). - 2051-8153 .- 2051-8161. ; 9:1, s. 145-161
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Journal article (peer-reviewed)abstract
- Tire and road wear particles (TRWP) are non-exhaust particulate matter generated by road transport means during the mechanical abrasion of tires, brakes and roads. TRWP accumulate on the roadsides and are transported into the aquatic ecosystem during stormwater runoffs. Due to their size (sub-millimetric) and rubber content (elastomers), TRWP are considered microplastics (MPs). While the amount of the MPs polluting the water ecosystem with sizes from similar to 5 mu m to more than 100 mu m is known, the fraction of smaller particles is unknown due to the technological gap in the detection and analysis of <5 mu m MPs. Here we show that Raman tweezers, a combination of optical tweezers and Raman spectroscopy, can be used to trap and chemically analyze individual TRWPs in a liquid environment, down to the sub-micrometric scale. Using tire particles mechanically grinded from aged car tires in water solutions, we show that it is possible to optically trap individual sub-micron particles, in a so-called 2D trapping configuration, and acquire their Raman spectrum in few tens of seconds. The analysis is then extended to samples collected from a brake test platform, where we highlight the presence of sub-micrometric agglomerates of rubber and brake debris, thanks to the presence of additional spectral features other than carbon. Our results show the potential of Raman tweezers in environmental pollution analysis and highlight the formation of nanosized TRWP during wear.
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| 3. |
- Ntoumanis, N., et al.
(author)
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Longitudinal associations between exercise identity and exercise motivation: A multilevel growth curve model approach
- 2018
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In: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 28:2, s. 746-753
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Journal article (peer-reviewed)abstract
- Past work linking exercise identity and exercise motivation has been cross-sectional. This is the first study to model the relations between different types of exercise identity and exercise motivation longitudinally. Understanding the dynamic associations between these sets of variables has implications for theory development and applied research. This was a longitudinal survey study. Participants were 180 exercisers (79 men, 101 women) from Greece, who were recruited from fitness centers and were asked to complete questionnaires assessing exercise identity (exercise beliefs and role-identity) and exercise motivation (intrinsic, identified, introjected, external motivation, and amotivation) three times within a 6month period. Multilevel growth curve modeling examined the role of motivational regulations as within- and between-level predictors of exercise identity, and a model in which exercise identity predicted exercise motivation at the within- and between-person levels. Results showed that within-person changes in intrinsic motivation, introjected, and identified regulations were positively and reciprocally related to within-person changes in exercise beliefs; intrinsic motivation was also a positive predictor of within-person changes in role-identity but not vice versa. Between-person differences in the means of predictor variables were predictive of initial levels and average rates of change in the outcome variables. The findings show support to the proposition that a strong exercise identity (particularly exercise beliefs) can foster motivation for behaviors that reinforce this identity. We also demonstrate that such relations can be reciprocal overtime and can depend on the type of motivation in question as well as between-person differences in absolute levels of these variables. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
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| 4. |
- Polimeno, P., et al.
(author)
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Optical tweezers and their applications
- 2018
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In: Journal of Quantitative Spectroscopy & Radiative Transfer. - : Elsevier BV. - 0022-4073. ; 218, s. 131-150
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Journal article (peer-reviewed)abstract
- Optical tweezers, tools based on strongly focused light, enable optical trapping, manipulation, and characterisation of a wide range of microscopic and nanoscopic materials. In the limiting cases of spherical particles either much smaller or much larger than the trapping wavelength, the force in optical tweezers separates into a conservative gradient force, which is proportional to the light intensity gradient and responsible for trapping, and a non-conservative scattering force, which is proportional to the light intensity and is generally detrimental for trapping, but fundamental for optical manipulation and laser cooling. For non-spherical particles or at intermediate (meso)scales, the situation is more complex and this traditional identification of gradient and scattering force is more elusive. Moreover, shape and composition can have dramatic consequences for optically trapped particle dynamics. Here, after an introduction to the theory and practice of optical forces with a focus on the role of shape and composition, we give an overview of some recent applications to biology, nanotechnology, spectroscopy, stochastic thermodynamics, critical Casimir forces, and active matter. (C) 2018 Elsevier Ltd. All rights reserved.
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| 5. |
- Sivaramakrishnan, Hamsini, et al.
(author)
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Psychosocial outcomes of sport participation for middle-aged and older adults : a systematic review and meta-analysis
- 2024
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In: International Review of Sport and Exercise Psychology. - Oxon : Routledge. - 1750-984X .- 1750-9858. ; 17:1, s. 398-419
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Journal article (peer-reviewed)abstract
- © 2021 Informa UK Limited, trading as Taylor & Francis Group.Narrative reviews indicate psychological and social benefits of sport participation for the ageing population. However, no quantitative synthesis of quantitative studies on this topic has been conducted yet. We evaluated the magnitude and heterogeneity of the effects of sport participation on psychosocial outcomes for middle-aged and older adults (>35 years). Ten databases were searched in July 2020. Quantitative studies (k = 25) of middle-aged and older adults, measuring at least one psychosocial outcome of sport participation were included. Multilevel meta-analysis showed that the association between sport participation and psychosocial outcomes was small, yet significant. Moderation analyses revealed that the pooled effect differed according to outcome type; small to moderate associations were observed for social, positive psychological, perceived physical, and cognitive outcomes, but not for negative psychological outcomes. Risk of bias, assessed using the QualSyst tool, indicated low quality of evidence. Our findings suggest that sport participation is associated with multiple psychosocial benefits for middle-aged and older adults that appear invariant across participant-related and sport-related characteristics. We found no evidence of publication bias, but studies were underpowered and rated as low quality. Our review provides quantitative evidence for the psychosocial benefits of sport participation for adults, complementing existing qualitative research on this topic.
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| 6. |
- Stenling, Andreas, et al.
(author)
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Exploring longitudinal measurement invariance and the continuum hypothesis in the Swedish version of the Behavioral Regulation in Sport Questionnaire (BRSQ): An exploratory structural equation modeling approach
- 2018
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In: Psychology of Sport and Exercise. - Amsterdam : Elsevier BV. - 1469-0292 .- 1878-5476. ; 36, s. 187-196
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Journal article (peer-reviewed)abstract
- Objectives: The aims of the present study were to: (a) examine longitudinal measurement invariance in the Swedish version of the Behavioral Regulations in Sport Questionnaire (BRSQ) and (b) examine the continuum hypothesis of motivation as postulated within self-determination theory. Design: Two-wave survey. Method: Young competitive athletes (N = 354) responded to the BRSQ early in the season (November) and at the end of the athletic season (April). Data were analyzed using exploratory structural equation modeling (ESEM) and bifactor ESEM. Results: We found support for strict longitudinal measurement invariance in the BRSQ. Latent mean comparisons showed an increase in external regulation and amotivation across the season. The latent factor correlations indicated some deviations from a simplex pattern related to amotivation, external regulation, and introjected regulation. In the bifactor model, intrinsic motivation items had negative factor loadings on the global factor, identified regulation items had factor loadings approaching zero, and introjected and external regulation and amotivation items all had moderate to strong positive factor loadings. Conclusion: The present study adds longitudinal measurement invariance to the psychometric evidence of the BRSQ. Research on why the latent means of the behavioral regulations changed over the athletic season is warranted. The continuum hypothesis was partially supported. Latent factor correlations and factor loadings on the global factor in the bifactor ESEM highlighted that the discriminant validity of the controlled regulations and amotivation needs further investigation. © 2018 Elsevier Ltd
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