Thermoelectric response from grain boundaries and lattice distortions in crystalline gold devices.

The electronic Seebeck response in a conductor involves the energy-dependent mean free path of the charge carriers and is affected by crystal structure, scattering from boundaries and defects, and strain. Previous photothermoelectric (PTE) studies have suggested that the thermoelectric properties of polycrystalline metal nanowires are related to grain structure, although direct evidence linking crystal microstructure to the PTE response is difficult to elucidate. Here, we show that room temperature scanning PTE measurements are sensitive probes that can detect subtle changes in the local Seebeck coefficient of gold tied to the underlying defects and strain that mediate crystal deformation.

Direct imaging of short-range order and its impact on deformation in Ti-6Al.

Chemical short-range order (SRO) within a nominally single-phase solid solution is known to affect the mechanical properties of alloys. While SRO has been indirectly related to deformation, direct observation of the SRO domain structure, and its effects on deformation mechanisms at the nanoscale, has remained elusive. Here, we report the direct observation of SRO in relation to deformation using energy-filtered imaging in a transmission electron microscope (TEM).

High-Throughput Growth of Microscale Gold Bicrystals for Single-Grain-Boundary Studies.

The study of grain boundaries is the foundation to understanding many of the intrinsic physical properties of bulk metals. Here, the preparation of microscale thin-film gold bicrystals, using rapid melt growth, is presented as a model system for studies of single grain boundaries. This material platform utilizes standard fabrication tools and supports the high-yield growth of thousands of bicrystals per wafer, each containing a grain boundary with a unique <111> tilt character.

Metallurgy. Origin of dramatic oxygen solute strengthening effect in titanium.

Structural alloys are often strengthened through the addition of solute atoms. However, given that solute atoms interact weakly with the elastic fields of screw dislocations, it has long been accepted that solution hardening is only marginally effective in materials with mobile screw dislocations. By using transmission electron microscopy and nanomechanical characterization, we report that the intense hardening effect of dilute oxygen solutes in pure α-Ti is due to the interaction between oxygen and the core of screw dislocations that mainly glide on prismatic planes.

Prestorage leukoreduction ameliorates the effects of aging on banked blood.

Background: Previous studies have demonstrated that the transfusion of older blood is independently associated with higher rates of infectious complications, multiple organ failure, and mortality. Putative mechanisms implicate leukocytes in stored blood that generate immunomodulatory mediators as the stored blood ages. The purpose of this retrospective cohort study was to describe the effect of prestorage leukoreduction (PS-LR) on the detrimental clinical effects of increasing age on blood products used in trauma patients.

Sweet success: Ionic liquids derived from non-nutritive sweeteners.

The anions of the sweeteners saccharin and acesulfame form ionic liquids when paired with a variety of organic cations.