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- Sakatani, N., et al.
(författare)
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Anomalously porous boulders on (162173) Ryugu as primordial materials from its parent body
- 2021
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Ingår i: Nature Astronomy. - : Springer Nature. - 2397-3366. ; 5:8, s. 766-774
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Tidskriftsartikel (refereegranskat)abstract
- Planetesimals—the initial stage of the planetary formation process—are considered to be initially very porous aggregates of dusts1,2, and subsequent thermal and compaction processes reduce their porosity3. The Hayabusa2 spacecraft found that boulders on the surface of asteroid (162173) Ryugu have an average porosity of 30–50% (refs. 4,5,6), higher than meteorites but lower than cometary nuclei7, which are considered to be remnants of the original planetesimals8. Here, using high-resolution thermal and optical imaging of Ryugu’s surface, we discovered, on the floor of fresh small craters (<20 m in diameter), boulders with reflectance (~0.015) lower than the Ryugu average6 and porosity >70%, which is as high as in cometary bodies. The artificial crater formed by Hayabusa2’s impact experiment9 is similar to these craters in size but does not have such high-porosity boulders. Thus, we argue that the observed high porosity is intrinsic and not created by subsequent impact comminution and/or cracking. We propose that these boulders are the least processed material on Ryugu and represent remnants of porous planetesimals that did not undergo a high degree of heating and compaction3. Our multi-instrumental analysis suggests that fragments of the highly porous boulders are mixed within the surface regolith globally, implying that they might be captured within collected samples by touch-down operations10,11.
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| 6. |
- Hidaka, R., et al.
(författare)
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Impact of the Comprehensive Awareness Modification of Mouth, Chewing and Meal (CAMCAM) Program on the Attitude and Behavior Towards Oral Health and Eating Habits as Well as the Condition of Oral Frailty : A Pilot Study
- 2023
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Ingår i: The Journal of Nutrition, Health & Aging. - : Springer-Verlag Italia s.r.l.. - 1279-7707 .- 1760-4788. ; 27:5, s. 340-
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Preserving sufficient oral function and maintaining adequate nutrition are essential for preventing physical frailty and the following long-term care. We recently developed the 6-month Comprehensive Awareness Modification of Mouth, Chewing And Meal (CAMCAM) program, in which participants gather monthly to learn about oral health and nutrition while eating a textured lunch together. This study examined whether the CAMCAM program could improve attitude and behavior towards oral health, mastication, and diet as well as ameliorate oral frailty in community-dwelling older adults. Design: Single-arm pre-post comparison study. Setting and Participants: A total of 271 community-dwelling adults (72.3 ± 5.7 years of age; 159 women [58.7%]) in 4 Japanese municipalities were recruited, of which 249 participants (92%) were assessed at the final evaluation. Intervention: Participants gathered once a month at community centers to learn about oral health and nutrition while eating a “munchy” textured lunch containing proper nutrition. Measurements: Oral frailty, frailty, and eating behavior were evaluated with the Oral Frailty Index-8 (OFI-8), Kihon checklist (KCL), and CAMCAM checklist, respectively. Participants were divided into Oral frailty (OF) and Robust groups according to OFI-8 scores. The differences in KCL and CAMCAM checklist results between the OF and Robust groups were statistically tested along with changes in scores after the program. Results: KCL and CAMCAM checklist scores were significantly lower in the OF group at the initial assessment. OFI-8 and KCL findings were significantly improved in the OF group after completing the program (all P <0.05). Regarding the CAMCAM checklist, awareness of chewing improved significantly in the Robust group (P=0.009), with a similar tendency in the OF group (P=0.080). Conclusion: The findings of this pilot study suggest that the CAMCAM program may improve both oral and systemic frailty in addition to attitudes towards chewing, oral health, and meals, especially in individuals with oral frailty. The CAMCAM program merits expansion as a community-based frailty prevention program.
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