Biomedical applications of aerospace-generated technology Quarterly report, 1 Sep. - 30 Nov. 1968

Biomedical applications of aerospace generated technolog

Biomedical applications of aerospace- generated technology Quarterly report, 1 Dec. 1968 - 28 Feb. 1969

Biomedical applications team for transferring aerospace generated technology to nonaerospace biomedical fiel

Point-contact spectroscopy in heavy-fermion superconductors

We develop a minimal model to calculate point-contact spectra between a metallic tip and a superconducting heavy-fermion system. We apply our tunneling model to the heavy fermion CeCoIn5, both in the normal and superconducting state. In point-contact and scanning tunneling spectroscopy many heavy-fermion materials, like CeCoIn5, exhibit an asymmetric differential conductance, dI/dV, combined with a strongly suppressed Andreev reflection signal in the superconducting state. We argue that both features may be explained in terms of a multichannel tunneling model in the presence of localized states near the interface. We find that it is not sufficient to tunnel into two itinerant bands of light and heavy electrons to explain the Fano line shape of the differential conductance. Localized states in the bulk or near the interface are an essential component for quantum interference to occur when an electron tunnels from the metallic tip of the point contact into the heavy-fermion system.Comment: 13 pages, 9 figures. Accepted for publication in Physical Review

Biomedical applications of aerospace generated technology, task 1 Final report, 1 Jun. 1968 - 31 May 1969

Biomedical applications of aerospace generated technolog

A high serum level of eotaxin (CCL 11) is associated with less radiographic progression in early rheumatoid arthritis patients

Introduction Prognosis in rheumatoid arthritis (RA) is difficult to assess. The aim of this study was to examine whether serum levels of a spectrum of cytokines were predictive of radiographic progression in early RA patients. Methods A total of 82 early RA patients (disease duration < 1 year) were followed for 12 months. Clinical assessments, X-rays of hands and magnetic resonance imaging (MRI) of the dominant wrist were assessed at baseline and after 3, 6 and 12 months. The X-rays were scored according to the van der Heijde modified Sharp score (vdHSS). Cytokine analyses were performed with multiplex technology. Associations between cytokines and radiographic progression were examined by logistic regression. Results In all, 49% of the patients developed radiographic progression. The median (interquartile range (IQR)) baseline eotaxin level (pg/ml) was significantly lower in patients with (193 (119 to 247)) than without progression (265 (166 to 360)). In the univariate logistic regression analyses, eotaxin was negatively associated to radiographic progression, and this association was maintained in the multivariate model with an odds ratio (OR) (95% confidence interval (CI)) for progression of 0.58 (0.41 to 0.82) per 50 pg/ml increase in eotaxin level. None of the other measured cytokines showed any association to radiographic progression. Conclusion This study raises the hypothesis that high serum levels of eotaxin predict less radiographic progression in early RA patients

Local Anisotropy of Fluids using Minkowski Tensors

Statistics of the free volume available to individual particles have previously been studied for simple and complex fluids, granular matter, amorphous solids, and structural glasses. Minkowski tensors provide a set of shape measures that are based on strong mathematical theorems and easily computed for polygonal and polyhedral bodies such as free volume cells (Voronoi cells). They characterize the local structure beyond the two-point correlation function and are suitable to define indices $0\leq \beta_\nu^{a,b}\leq 1$ of local anisotropy. Here, we analyze the statistics of Minkowski tensors for configurations of simple liquid models, including the ideal gas (Poisson point process), the hard disks and hard spheres ensemble, and the Lennard-Jones fluid. We show that Minkowski tensors provide a robust characterization of local anisotropy, which ranges from $\beta_\nu^{a,b}\approx 0.3$ for vapor phases to $\beta_\nu^{a,b}\to 1$ for ordered solids. We find that for fluids, local anisotropy decreases monotonously with increasing free volume and randomness of particle positions. Furthermore, the local anisotropy indices $\beta_\nu^{a,b}$ are sensitive to structural transitions in these simple fluids, as has been previously shown in granular systems for the transition from loose to jammed bead packs