In longitudinal studies where walking and health are ascertained at every wave, limited-bias estimates can provide better estimates of the benefits of walking. A surprisingly small increase in walking was associated with meaningful BIX 1294 health benefits.”
“Introduction:
PET imaging in plants is receiving increased interest as a new strategy to measure plant responses to environmental stimuli and as a tool for phenotyping genetically engineered plants. PET imaging in plants, however, poses new challenges. In particular, the leaves of most plants are so thin that a large fraction of positrons emitted from PET isotopes ((18)F, (11)C, (13)N) escape while even state-of-the-art PET cameras have significant partial-volume errors for such thin objects. Although these limitations are acknowledged by researchers, little data have been published on them.
Methods: Here we measured the magnitude and distribution of escaping positrons from the leaf of Nicotiana tabacum for the radionuclides (18)F, (11)C and (13)N using a commercial small-animal PET scanner. Imaging results were compared to radionuclide concentrations measured
from dissection and counting and to a Monte Carlo simulation using GATE (Geant4 Application for Tomographic Emission).
Results: Simulated and experimentally determined escape fractions were consistent. The fractions of positrons (mean +/- S.D.) escaping the leaf parenchyma were measured to be 59 +/- 1.1%, 64 +/- 4.4% and 67 +/- 1.9% for (18)F, (11)C and (13)N, respectively. Escape fractions were lower in thicker
mTOR inhibitor leaf areas like the midrib. Partial-volume averaging underestimated activity concentrations in the leaf blade by a factor of 10 to 15.
Conclusions: The foregoing effects combine to yield PET images whose contrast does not reflect the actual activity concentrations. These errors can be largely corrected by integrating activity along the PET axis perpendicular to the leaf surface, including detection of escaped positrons, and calculating concentration using a measured leaf thickness. (C) 2011 Elsevier Inc. All rights reserved.”
“Balance is among the most important prerequisites for safe and independent mobility. Whether musculoskeletal DCLK1 pain is related to standing balance impairment has received limited attention. The aim of this study was to examine the association of musculoskeletal pain with the control of balance in older people.
A total of 605 participants aged 75 years and older (mean age 80.4, 71 % women) were interviewed about presence and severity of musculoskeletal pain. Balance was measured by a force platform, and impaired balance was defined as a high sway velocity moment or inability to maintain semitandem standing.
Musculoskeletal pain was reported by 48% of the participants, of whom majority had moderate to severe pain in lower extremities or back.