Objective
The objective of this study was to evaluate the effects of mechanical loading on knee articular cartilage T1ρ and T2 relaxation times in patients with and without OA.
Design
MR images were acquired from 137 subjects with and without knee OA under two conditions: unloaded and loaded at 50% body weight. Three sequences were acquired: a high-resolution 3D-CUBE, a T1ρ relaxation time, and a T2 relaxation time sequences. Cartilage regions of interest included: medial and lateral femur (MF, LF); medial and lateral tibia (MT, LT), laminar analysis (superficial and deep layers), and subcompartments. Changes in relaxation times in response to loading were evaluated using generalized estimating equations adjusting for age, gender, and BMI.
Results
In response to loading, we observed significant reductions in T1ρ relaxation times in the MT and LT. In both the MF and LF, loading resulted in significant decreases in the superficial layer and significant increases in the deep layer of the cartilage for T1ρ and T2. All subcompartment of MT and LT showed significant reduction in T1ρ relaxation times. Reductions were larger for subjects with OA (range: 13–19% change) when compared to healthy controls (range: 3–13% change).
Conclusions
Loading of the cartilage resulted in significant changes in relaxation times in the femur and tibia, with novel findings regarding laminar and subcompartmental variations. In general, changes in relaxation times with loading were larger in the OA group suggesting that the collagen-proteoglycan matrix of subjects with OA is less capable of retaining water, and may reflect a reduced ability to dissipate loads.
Maternal anemia, particularly the severe type, adversely affects cord blood and breast milk iron status. Maternal nutritional status exerts a significant influence on fetal iron status but has little influence on breast milk iron content.
This is the first report on the critical nature of nanolattice formability of different particle size (~4-10nm) of monodispersed nickel nanoparticles. They exhibit strikingly hexagonal close-packed (hcp) nanolattices without extra forces, whenever trioctylphosphine is (one of) the surfactant(s) . This clearly establishes the unique role of nanolattice formability of trioctylphosphine. The c/a ratios are interestingly identical to those of atomic lattices. An attempt has also been made to explain them based on the balanced attractive and repulsive forces of the surfactant-generated cation-anion pairs on the surface of the nanoparticles. The present findings therefore will provide a far-reaching vista to fabrication of varieties of natural nanolattices and their understanding on applications in a new paradigm.
Notes and references
Chemists are generally familiar with polar reactions and radical reactions, in comparison, are underdeveloped. In the last few years, however, the novel concept of amalgamation of the above two in the form of radical‐polar crossover (RPCO) and polar‐radical crossover (PRCO) reactions has emerged as a valuable and powerful tool. This methodology tends to bridge the gap between the two as well as overcomes limitations of both radical and traditional polar chemistry. By bringing together the unorthodox chemistry of radicals with orthodox carbocations and carbanions, the green quotient of such reactions is significantly improved. The development and shaping up of this area in the last few years in the form of synthetically important transformations is summarised in this review.
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