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- Tamagawa, T., et al.
(författare)
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Correlation between musculoskeletal structure of the hand and primate locomotion: Morphometric and mechanical analysis in prehension using the cross- and triple-ratios
- 2020
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 15:5
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Tidskriftsartikel (refereegranskat)abstract
- Biometric ratios of the relative length of the rays in the hand have been analyzed between primate species in the light of their hand function or phylogeny. However, how relative lengths among phalanges are mechanically linked to the grasping function of primates with different locomotor behaviors remains unclear. To clarify this, we calculated cross and triple-ratios, which are related to the torque distribution, and the torque generation mode at different joint angles using the lengths of the phalanges and metacarpal bones in 52 primates belonging to 25 species. The torque exerted on the finger joint and traction force of the flexor tendons necessary for a cylindrical grip and a suspensory hand posture were calculated using the moment arm of flexor tendons measured on magnetic resonance images, and were compared among Hylobates spp., Ateles sp., and Papio hamadryas. Finally, the torques calculated from the model were validated by a mechanical study detecting the force exerted on the phalanx by pulling the digital flexor muscles during suspension in these three species. Canonical discriminant analysis of cross and triple-ratios classified primates almost in accordance with their current classification based on locomotor behavior. The traction force was markedly reduced with flexion of the MCP joint parallel to the torque in brachiating primates; this was notably lower in the terrestrial quadrupedal primates than in the arboreal primates at mild flexion. Our mechanical study supported these features in the torque and traction force generation efficiencies. Our results suggest that suspensory or terrestrial quadrupedal primates have hand structures that can exert more torque at a suspensory posture, or palmigrade and digitigrade locomotion, respectively. Furthermore, our study suggests availability of the cross and triple-ratios as one of the indicators to estimate the hand function from the skeletal structure.
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| 2. |
- Ota, S., et al.
(författare)
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Charge resolution of CR-39 plastic nuclear track detectors for intermediate energy heavy ions
- 2011
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 269:12, s. 1382-1388
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Tidskriftsartikel (refereegranskat)abstract
- The charge resolution (delta Z) for heavy ions (nuclear charge: Z = 60 mu m (30 h etching), saturation occurs and there is no further improvement in delta Z. Analysis of the correlations between projectile Z, energy, detector response, and fluctuation of the response make it possible to develop a model to predict the delta Z for projectiles of given Z and energy. The predicted and measured values of delta Z show good agreement within 10%. We conclude that 4
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| 3. |
- Ota, S., et al.
(författare)
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Improvement of charge resolution for trans-iron nuclei (Z≥30) in CR-39 plastic nuclear track detectors using trajectory tracing technique
- 2011
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Ingår i: Astrophysics and Space Sciences Transactions. - : Copernicus GmbH. - 1810-6528 .- 1810-6536. ; 7:4, s. 495-500
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Tidskriftsartikel (refereegranskat)abstract
- Charge identification of trans-iron nuclei (nuclear charge: Z≥ 30) using CR-39 plastic nuclear track detector (PNTD) is essential as a part of an effort to our future measurements of the projectile charge changing cross sections for galactic cosmic ray nuclei, but extremely hard. Therefore, an improvement method of the charge resolution (δZ) for 350 MeV/n Ge in CR-39 PNTD using the trajectory tracing technique with averaging the signals of nuclear tracks for each ion was studied. Eight sheets of CR-39 PNTDs were aligned and exposed to Ge beam behind a graphite target to produce projectile fragments. Average of the nuclear track data was taken over 16 detector surfaces for each ion, then the δZ of Ge was successfully improved from 0.31 charge unit on single surface to 0.15 charge unit in rms, which is good enough for making the precise cross section measurements and no other experiments using CR-39 PNTDs or the other passive detectors have achieved such a good δZ for the trans-iron nuclei with ≥Z 50 (β: relativistic velocity). This method will be very important for our future cross section measurements toward the study of galactic cosmic ray origin. © 2011 Author(s).
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