Background:Changes in thyroid hormone levels are commonly recognized characters among the elderly,which were reported to potentially influence incident frailty.Therefore,we examined the cross-sectional associations of...Background:Changes in thyroid hormone levels are commonly recognized characters among the elderly,which were reported to potentially influence incident frailty.Therefore,we examined the cross-sectional associations of thyroid hormones(THs)with frailty as well as the five components characterizing frailty(fatigue,resistance,ambulation,number ofillnesses,and loss of weight)among the oldest-old.Methods:Four hundred and eighty-seven community-dwelling oldest-old from a local community in Haidian District,Beijing,participated in our recruitment campaign between April 2019 and May 2020.The primary outcomes were a definitive diagnosis of frailty according to the FRAIL scale(Fatigue,Resistance,Ambulation,Illnesses,Loss of weight)and a positive score for each frailty subdomain.Demographic information(age,sex,marital status,and educational status),comorbidities,and details on the participants lifestyles were recorded.Serum THs including free triodothyronin(fT3),triiodothyronine(T3),free thyroxine(fT4),and thyroxine(T4)and thyroid stimulating hormone(TSH)levels were also measured at the beginning of our study.Logistic regressions were conducted to screen for potential risk factors for frailty and its subdomains.Results:Among the total 487 subjects at enrollment,60(12.23%)of them were diagnosed with subclinical hypothyroidism and 110(22.59%)of the total population scored positive for frailty.Logistic regression analyses adjusted for all potential confounders,showed that frailty was significantly associated with the serum TSH concentration(odds ratio[OR]:1.06),fT3 concentration(OR:0.54),and subclinical hypothyroidism score(OR:2.18).The association between fT4 and frailty was absent in our observational study.The fT3/fT4 ratio characterizing peripheral hormone conversion was also tested to be correlated with frailty.Conclusion:Subclinical hypothyroidism,higher TSH level,lower fT3 level,and decreased fT3/fT4 ratio were all associated with frailty assessed by the FRAIL scale among the community-dwelling oldest-old,suggesting a relevant role of thyroid function in aging.Future longitudinal studies are warranted to determine the casual relationship between thyroid dysfunction and frailty in the oldest-old.展开更多
In this study,the discrete element method was combined with physical experiments to examine the capsule filling practice in the hot-isostatic-pressing process and to study the densification of spherical particles in a...In this study,the discrete element method was combined with physical experiments to examine the capsule filling practice in the hot-isostatic-pressing process and to study the densification of spherical particles in a three-way pipe capsule for offshore engineering under mechanical vibration conditions.The effects of vibration parameters—such as the vibration time,vibration frequency,vibration amplitude,rolling friction coefficient,sliding friction coefficient,recovery coefficient,and other particle properties—on the filling density were analyzed.The results showed that the packing density in the three-way capsule could be increased considerably using a vibration frequency of 40 Hz and a vibration amplitude of 2.5 mm.The contact form between particles in the vibration-assisted mold-filling process was determined and the particle velocity field,compression force,and coordination number under a single harmonic vibration period were analyzed.The real-time motion of the particles at the micro level was visualized,and the mechanism of the mechanical vibration effect on mold filling and densification was explored.The distribution and evolution of the coordination number indicated that the distribution of the filling density was uneven,and that the change in the coordination number of particles at the bottom exhibited no major response to the vibration.展开更多
基金funded by grants from NCRCG-PLAGH-2022004the Military Healthcare Research Program(No.21BJZ26,18BJZ32).
文摘Background:Changes in thyroid hormone levels are commonly recognized characters among the elderly,which were reported to potentially influence incident frailty.Therefore,we examined the cross-sectional associations of thyroid hormones(THs)with frailty as well as the five components characterizing frailty(fatigue,resistance,ambulation,number ofillnesses,and loss of weight)among the oldest-old.Methods:Four hundred and eighty-seven community-dwelling oldest-old from a local community in Haidian District,Beijing,participated in our recruitment campaign between April 2019 and May 2020.The primary outcomes were a definitive diagnosis of frailty according to the FRAIL scale(Fatigue,Resistance,Ambulation,Illnesses,Loss of weight)and a positive score for each frailty subdomain.Demographic information(age,sex,marital status,and educational status),comorbidities,and details on the participants lifestyles were recorded.Serum THs including free triodothyronin(fT3),triiodothyronine(T3),free thyroxine(fT4),and thyroxine(T4)and thyroid stimulating hormone(TSH)levels were also measured at the beginning of our study.Logistic regressions were conducted to screen for potential risk factors for frailty and its subdomains.Results:Among the total 487 subjects at enrollment,60(12.23%)of them were diagnosed with subclinical hypothyroidism and 110(22.59%)of the total population scored positive for frailty.Logistic regression analyses adjusted for all potential confounders,showed that frailty was significantly associated with the serum TSH concentration(odds ratio[OR]:1.06),fT3 concentration(OR:0.54),and subclinical hypothyroidism score(OR:2.18).The association between fT4 and frailty was absent in our observational study.The fT3/fT4 ratio characterizing peripheral hormone conversion was also tested to be correlated with frailty.Conclusion:Subclinical hypothyroidism,higher TSH level,lower fT3 level,and decreased fT3/fT4 ratio were all associated with frailty assessed by the FRAIL scale among the community-dwelling oldest-old,suggesting a relevant role of thyroid function in aging.Future longitudinal studies are warranted to determine the casual relationship between thyroid dysfunction and frailty in the oldest-old.
基金financial support of Beijing Nova Program(grant No.2022139).
文摘In this study,the discrete element method was combined with physical experiments to examine the capsule filling practice in the hot-isostatic-pressing process and to study the densification of spherical particles in a three-way pipe capsule for offshore engineering under mechanical vibration conditions.The effects of vibration parameters—such as the vibration time,vibration frequency,vibration amplitude,rolling friction coefficient,sliding friction coefficient,recovery coefficient,and other particle properties—on the filling density were analyzed.The results showed that the packing density in the three-way capsule could be increased considerably using a vibration frequency of 40 Hz and a vibration amplitude of 2.5 mm.The contact form between particles in the vibration-assisted mold-filling process was determined and the particle velocity field,compression force,and coordination number under a single harmonic vibration period were analyzed.The real-time motion of the particles at the micro level was visualized,and the mechanism of the mechanical vibration effect on mold filling and densification was explored.The distribution and evolution of the coordination number indicated that the distribution of the filling density was uneven,and that the change in the coordination number of particles at the bottom exhibited no major response to the vibration.
