Band structure and optical properties of germanium sheet polymers

The band structure of H-terminated Ge sheet polymers is calculated using density-functional theory in the local density approximation and compared to the optical properties of epitaxial polygermyne layers as determined from reflection, photoluminescence, and photoluminescence excitation measurements. A direct band gap of 1.7 eV is predicted and a near resonant excitation of the photoluminescence is observed experimentally close to this energy

The hemiplegic arm: Interrater reliability and concurrent validity of passive range of motion measurements

Purpose. To assess whether our measurement protocol using two raters simultaneously yielded reliable passive range of motion measurements of the hemiplegic arm. Additionally, motion ranges were correlated to several factors to examine the concurrent validity of these measurements. Method. Two raters simultaneously assessed five arm motions at baseline, after five and ten weeks in respectively 18, 13 and 12 stroke patients. One tester made the passive movement and the other read the hydrogoniometer. Raters then switched roles. Results. Intraclass correlation coefficients revealed high agreement between the raters with intraclass correlation coefficients (ICCs) ranging between 0.84 and 0.99. Standard errors of measurement and smallest detectable differences were large for shoulder abduction. Significant correlations were found between shoulder external rotation and flexion. All arm motions correlated negatively to pain at the end range of these motions. Shoulder external rotation and flexion were significantly correlated to the time post stroke. Concurrent validity with Ashworth Scale, Fugl-Meyer Assessment and Barthel Index was limited. Conclusions. The current measurement protocol yielded high reliability indices and seems useful for further use. However, standard error of measurement and smallest detectable difference for shoulder abduction were high, implying the neccesity to include a large sample size in future studies. Correlations revealed that restricted range of arm motions relate to the time post-stroke and coincide with pain

Cholecalciferol or 25-Hydroxycholecalciferol Supplementation Does Not Affect Muscle Strength and Physical Performance in Prefrail and Frail Older Adults

<p>Background: Vitamin D supplementation is proposed as a potential treatment strategy to counteract functional decline in older adults. However, data from randomized trials are either limited or inconsistent. Objective: This study investigated the effect of daily supplementationwith 25-hydroxycholecalciferol [25(OH)D₃] or cholecalciferol (vitamin D₃) on muscle strength and physical performance in older adults. Methods: This was a randomized, double-blind, placebo-controlled trial of 6 mo including 78 prefrail or frail (according to the Fried criteria), community-dwelling older adults (n = 43 men) aged ≥65 y, with a baseline 25-hydroxyvitamin D [25(OH)D] concentration between 20 and 50 nmol/L. Participants were supplemented daily with 10 μg 25(OH)D₃, 20 μg vitamin D₃, or a placebo capsule. Serum 25(OH)D was measured by liquid chromatography-tandem mass spectrometry. The primary outcome wasmaximal isometric knee-extension strength (Biodex System 4); secondary outcomes included knee-flexion and hand grip strength, Short-Physical Performance Battery score, Timed Up and Go score, postural sway, muscle mass (dual-energy X-ray absorptiometry), and muscle fiber type and size. Results: The mean baseline serum 25(OH)D concentration was 37.7 nmol/L (95% CI: 35.4, 39.9 nmol/L). After 6 mo of supplementation, concentrations increased to 98.7 nmol/L (95% CI: 93.1, 104.4 nmol/L) in the 25(OH)D₃ group and to 72.0 nmol/L (95% CI: 66.1, 77.8 nmol/L) in the vitamin D₃ group, compared with 47.5 nmol/L (95% CI: 41.8, 53.3 nmol/L) in the placebo group (P-interaction &lt; 0.01). Knee-extension strength did not significantly change in the 25(OH)D₃ group (5.9 Nm; 95% CI: -6.2, 18.0 Nm), in the vitamin D₃ group (5.5 Nm; 95% CI: -6.8, 17.8 Nm), or in the placebo group (1.8 Nm; 95% CI: -10.7, 14.4 Nm) (P-interaction = 0.74). Furthermore, mean changes in physical performance tests, muscle mass, and muscle fiber type and size did not differ between the groups. Conclusion: Increasing the serum 25(OH)D concentration over a period of 6 mo did not significantly change muscle strength and physical performance in prefrail and frail older adults.</p