Developing a scoring system based on physiological and functional measurements is critical to test the efficacy of potential interventions for sarcopenia and frailty in aging animal models; therefore, the aim of this study was to develop a neuromuscular healthspan scoring system (NMHSS). We examined three ages of male C57BL/6 mice: adults (6-7 months old, 100% survival), old (24-26 months old, 75% survival), and elderly group (>28 months old, ≤50% survival)-as well as mice along this age continuum. Functional performance (as determined by the rotarod and inverted-cling grip test) and in vitro muscle contractility were the determinants. A raw score was derived for each determinant, and the NMHSS was then derived as the sum of the individual determinant scores. In comparison with individual determinants, the NMHSS reduced the effect of individual variability within age groups, thus potentially providing an enhanced ability to detect treatment effects in future studies.

Ln(Mg1/2Ti1/2)O3 (Ln = Dy, La, Nd, Pr, Sm, Y) compositions have been prepared, and their pertinent properties for use as thin film substrates for YBa2Cu3Ox (YBCO) were measured. X-ray diffraction shows that Ln(Mg1/2Ti1/2)O3 compositions have noncubic symmetry and the GdFeO3-type structure. Dielectric constant measurements revealed values between 22 and 27, which are larger than those of the LnAlO3 family. Quality factor (=1/ tan δ) of the ceramic specimens measured at room temperature was larger than 3000 at 10 GHz. Among the compounds, La(Mg1/2Ti1/2)O3 exhibited the highest dielectric constant and the lowest dielectric loss. Chemical reaction was observed between Ln(Mg1/2Ti1/2)O3 (Ln = Dy, Sm, Y) and YBCO after annealing a 1 : 1 mixture at 950 °C. Considering dielectric and physical properties, La(Mg1/2Ti1/2)O3 and Sm(Mg1/2Ti1/2)O3 were determined to be suitable substrates for YBCO thin film used in microwave applications.

Zn2SiO4 ceramics synthesized by the conventional solid‐state method exhibited a low Q×f value, possibly due to the formation of a ZnO second phase. However, with a small ZnO reduction from the Zn2SiO4 ceramics, the ZnO second phase disappeared and grain growth occurred due to the formation of a Si‐rich liquid phase. Specimens with a large grain size exhibited an improved Q×f value. In particular, the ceramics with nominal composition Zn1.8SiO3.8 sintered at 1300°C exhibited improved microwave dielectric properties of ɛr=6.6, Q×f=147 000 GHz, and τf=−22 ppm/°C.

Quantification of key outcome measures in animal models of aging is an important step preceding intervention testing. One such measurement, skeletal muscle power generation (force * velocity), is critical for dynamic movement. Prior research focused on maximum power (Pmax), which occurs around 30–40 % of maximum load. However, movement occurs over the entire load range. Thus, the primary purpose of this study was to determine the effect of age on power generation during concentric contractions in the extensor digitorum longus (EDL) and soleus muscles over the load range from 10 to 90 % of peak isometric tetanic force (P0). Adult, old, and elderly male C57BL/6 mice were examined for contractile function (6–7 months old, 100 % survival; ~24 months, 75 %; and ~28 months, <50 %, respectively). Mice at other ages (5–32 months) were also tested for regression modeling. We hypothesized and found that power decreased with age not only at Pmax but also over the load range. Importantly, we found greater age-associated deficits in both power and velocity when the muscles were contracting concentrically against heavy loads (>50 % P0). The shape of the force-velocity curve also changed with age (a/P0 increased). In addition, there were prolonged contraction times to maximum force and shifts in the distribution of the myosin light and heavy chain isoforms in the EDL. The results demonstrate that age-associated difficulty in movement during challenging tasks is likely due, in addition to overall reduced force output, to an accelerated deterioration of power production and contractile velocity under heavily loaded conditions.Electronic supplementary materialThe online version of this article (doi:10.1007/s11357-015-9773-1) contains supplementary material, which is available to authorized users.