Quantitative Three-Dimensional Measurements of Acetabular Fracture Displacement Could Be Predictive for Native Hip Survivorship

This study aims to develop a three-dimensional (3D) measurement for acetabular fracture displacement, determine the inter- and intra-observer variability, and correlate the measurement with clinical outcome. Three-dimensional models were created for 100 patients surgically treated for acetabular fractures. The ‘3D gap area’, the 3D surface between all the fracture fragments, was developed. The association between the 3D gap area and the risk of conversion to a total hip arthroplasty (THA) was determined by an ROC curve and a Cox regression analysis. The 3D gap area had an excellent inter-observer and intra-observer reliability. The preoperative median 3D gap area for patients without and with a THA was 1731 mm2 versus 2237 mm2. The median postoperative 3D gap area was 640 mm2 versus 845 mm2. The area under the curve was 0.63. The Cox regression analysis showed that a preoperative 3D gap area > 2103 mm2 and a postoperative 3D gap area > 1058 mm2 were independently associated with a 3.0 versus 2.4 times higher risk of conversion to a THA. A 3D assessment of acetabular fractures is feasible, reproducible, and correlates with clinical outcome. Three-dimensional measurements could be added to the current classification systems to quantify the level of fracture displacement and to assess operative results

New directions in point-contact spectroscopy based on scanning tunneling microscopy techniques (Review Article)

Igor Yanson showed 38 years ago for the first time a point-contact measurement where he probed the energy resolved spectroscopy of the electronic scattering inside the metal. Since this first measurement, the pointcontact spectroscopy (PCS) technique improved enormously. The application of the scanning probe microscopy (SPM) techniques in the late 1980s allowed achieving contacts with a diameter of a single atom. With the introduction of the mechanically controlled break junction technique, even spectroscopy on freely suspended chains of atoms could be performed. In this paper, we briefly review the current developments of PCS and show recent experiments in advanced scanning PCS based on SPM techniques. We describe some results obtained with both needle-anvil type of point contacts and scanning tunneling microscopy (STM). We also show our first attempt to lift up with a STM a chain of single gold atoms from a Au(110) surface

Out-of-equilibrium singlet-triplet Kondo effect in a single C_60 quantum dot

We have used an electromigration technique to fabricate a $\rm{C_{{60}}}$ single-molecule transistor (SMT). Besides describing our electromigration procedure, we focus and present an experimental study of a single molecule quantum dot containing an even number of electrons, revealing, for two different samples, a clear out-of-equilibrium Kondo effect. Low temperature magneto-transport studies are provided, which demonstrates a Zeeman splitting of the finite bias anomaly.Comment: 6 pages, 4 figure

Characterization of electromigration-induced gold nanogaps

We study the formation and. stability of nanometer-sized gaps, created by electromigration, in thin gold wires. After a wire breaks due to a high local current density, nanogaps of random size are found, all exhibiting tunneling behavior at low bias. Surprisingly, we find that small gaps (&lt;appr. 0.5 nm) can be closed again when a voltage of about 2 V is applied. For larger gaps this is not possible, but the gold does become unstable, leading to an apparent negative differential resistance. We relate these effects to field evaporation and field-enhanced diffusion, respectively.</p

Mechanics of lithographically defined break junctions

We investigate the mechanics of lithographically defined mechanically controllable break junctions, both theoretically and experimentally. It is shown that the relationship between controlled deflection and junction opening depends on the details of the break junction geometry. As a result the generally used formula for the “attenuation factor” r needs to be corrected by a factor ζ. For typical break junction geometries, we obtain 2≤ζ≤4.

Phonons heat transport at an atomic well boundary in ultrathin solid films

A model calculation is presented for the heat transport across an extended atomic well boundary separating two ultrathin solid films, due to the phonons coherent elastic scattering at the boundary. Using the matching method, the transmission spectra are calculated for the phonons coherent scattering, for all propagating frequencies, and incident angles from inside the films, and for different boundary elastic conditions. The group velocities of the phonon branches in the ultrathin material films are explicitly calculated as a function of frequency and incidence angle. The model is applied to a corresponding gold material system, where the individual thermal conductivities for the phonon branches of this system are numerically evaluated for different boundary conditions. The results show that the heat transport at the boundary may be reduced or enhanced by controlling its elastic properties. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2011