Multi-component modeling of quasielastic neutron scattering from phospholipid membranes.

We investigated molecular motions in the 0.3-350 ps time range of D2O-hydrated bilayers of 1-palmitoyl-oleoyl-sn-glycero-phosphocholine and 1,2-dimyristoyl-sn-glycero-phosphocholine in the liquid phase by quasielastic neutron scattering. Model analysis of sets of spectra covering scale lengths from 4.8 to 30 Å revealed the presence of three types of motion taking place on well-separated time scales: (i) slow diffusion of the whole phospholipid molecules in a confined cylindrical region; (ii) conformational motion of the phospholipid chains; and (iii) fast uniaxial rotation of the hydrogen atoms around their carbon atoms. Based on theoretical models for the hydrogen dynamics in phospholipids, the spatial extent of these motions was analysed in detail and the results were compared with existing literature data. The complex dynamics of protons was described in terms of elemental dynamical processes involving different parts of the phospholipid chain on whose motions the hydrogen atoms ride.

Low-energy vibrational dynamics of cesium borate glasses.

Low-temperature specific heat and inelastic light scattering experiments have been performed on a series of cesium borate glasses and on a cesium borate crystal. Raman measurements on the crystalline sample have revealed the existence of cesium rattling modes in the same frequency region where glasses exhibit the boson peak (BP). These localized modes are supposed to overlap with the BP in cesium borate glasses affecting its magnitude. Their influence on the low frequency vibrational dynamics in glassy samples has been considered, and their contribution to the specific heat has been estimated. Evidence for a relation between the changes of the BP induced by the increased amount of metallic oxide and the variations of the elastic medium has been provided.

Relation between low-temperature thermal conductivity and the specific heat of cesium borate glasses.

Low-temperature specific heat and thermal conductivity measurements have been performed on cesium borate glasses as a function of cesium oxide content. We have found experimental evidence of a concurrent growth of specific heat and thermal conductivity with increasing Cs(+) content. This finding shows the existence of an uncommon relationship between the peak in C(p)/T(3) and the plateau in thermal conductivity in glasses and represents the most intriguing result for these alkaline borate glasses. The role of local modes associated with heavy cations on the vibrational dynamics in oxide glasses has been considered. Furthermore, a possible correlation between low-temperature thermal properties and the structure on the nanometer length scale of these glasses is put forward.

Consumer satisfaction with a rehabilitation mobile outreach program.

Accessibility to rehabilitation services is often difficult for people with disabilities who live in rural areas. This study examined consumer satisfaction with a rehabilitation outreach approach that utilizes a mobile clinic to provide consultation services. The descriptive survey took place in fifteen rural communities in eastern and northeastern Ontario, Canada. Valid postconsultation mail surveys were completed by 143 consecutive patients with mixed diagnoses (or proxy family members) who had been seen during mobile clinic visits to their home communities (85.1% of patients approached). There were 59 men and 84 women, with an average age of 58.7 years. The main outcome measure was a consumer satisfaction scale. A high level of global satisfaction was reported, with 97.2% of respondents reporting a preference for community outreach over the alternative of traveling to an urban rehabilitation center. Enhanced accessibility was considered to be the major advantage of the outreach program, but concerns about the continuity of care were also expressed. Providing interdisciplinary rehabilitation consultation services on an outreach basis is associated with a high level of consumer satisfaction. From a consumer perspective, the outreach approach seems to be a viable way of addressing some of the rehabilitation needs of rural people with disabilities.