The surface tension of Co nanoparticles calculated using a liquid drop model was more than twice that of bulk material. The size-dependent vibrational properties were probed with temperature-dependent EXAFS measurements. Using a correlated anharmonic
Einstein model and thermodynamic perturbation theory, Einstein temperatures for both nanoparticles and bulk material were determined. Compared to bulk Co, the mean vibrational frequency of the smallest nanoparticles was reduced as attributed to a greater influence of loosely bonded, undercoordinated surface atoms relative to the effect of capillary pressure generated by surface curvature.”
“Schmidt et al (1) showed that MR imaging by using gadofluorine M, a fluorinated macrocyclic gadolinium-based contrast agent, enabled detection of disease progression in a model of muscular dystrophy in mice, whereas a macromolecular contrast agent did this website find more not. MR imaging with contrast agents such as gadofluorine M might ultimately be used in patients with muscular dystrophy to monitor disease progression and to assess the effectiveness of newer therapies currently under development.”
“Elastomeric biodegradable polyurethanes and polyphosphate have been developed using an L-tyrosine-based diphenolic monomer desaminotyrosine-tyrosine hexyl ester (DTH). Soft segments, which are polycaproloctone diol
(PCL) and polyethylene glycol (PEG) have been used for the synthesis of two biodegradable L-tyrosine polyurethanes (LTUs), which are PEG-C-DTH and PCL-C-DTH. An investigation of the physico-chemical properties shows that these polymers have dramatically different properties. By blending LTUs with L-tyrosine polyphosphate (LTP), we hope to produce a family
of materials with a wide range of thermal, morphological, surface, and degradative properties. Examination of the blends shows a smooth surface morphology with a partially phase-separated structure. These findings are consistent with the results obtained from thermal analysis of the blends. Hydrophilic nature of PEG imparts the PEG-based blends (PEG-C-DTH/LTP) with a significantly higher surface and bulk hydrophilicity compared with the PCL-based blends (PCL-C-DTH/LTP). Finally, the blends demonstrate a rapid initial hydrolytic degradation in phosphate buffered saline (PBS) followed by a significantly slower, prolonged degradation. The observed trend Cyclosporin A may occur due to the rapid hydrolytic degradation rate of the polyphosphate polymer followed by the degradation of the polyurethane component. Thus, tuning the physical properties by blending LTUs with LTP may be useful for drug delivery device and soft tissue engineering scaffold applications. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 3235-3247, 2009″
“To provide bioelectrets with controlled electrical energy, the polarization and relaxation characteristics of hydroxyapatite (HA) ceramic electrets were investigated in terms of poling conditions and microstructures.