The study of quantum phenomena in semiconductors requires epitaxial structures with exceptionally high charge-carrier mobilities. Furthermore, low-temperature mobilities are highly sensitive probes of the quality of epitaxial layers, because they are limited by impurity and defect scattering. Unlike many other complex oxides, electron-doped SrTiO(3) single crystals show high (approximately 10(4) cm(2) V(-1) s(-1)) electron mobilities at low temperatures. High-mobility, epitaxial heterostructures with SrTiO(3) have recently attracted attention for thermoelectric applications, field-induced superconductivity and two-dimensional (2D) interface conductivity. Epitaxial SrTiO(3) thin films are often deposited by energetic techniques, such as pulsed laser deposition. Electron mobilities in such films are lower than those of single crystals. In semiconductor physics, molecular beam epitaxy (MBE) is widely established as the deposition method that produces the highest mobility structures. It is a low-energetic, high-purity technique that allows for low defect densities and precise control over doping concentrations and location. Here, we demonstrate controlled doping of epitaxial SrTiO(3) layers grown by MBE. Electron mobilities in these films exceed those of single crystals. At low temperatures, the films show Shubnikov-de Haas oscillations. These high-mobility SrTiO(3) films allow for the study of the intrinsic physics of SrTiO(3) and can serve as building blocks for high-mobility oxide heterostructures.

The human Equilibrative Nucleoside Transporter 1 (hENT1), a member of the SLC29 family, plays crucial roles in adenosine signaling, cellular uptake of nucleoside for DNA and RNA synthesis, and nucleoside-derived anticancer and antiviral drug transport in human. Because of its central role in adenosine signaling, it is the target of adenosine reuptake inhibitors (AdoRI), several of which are clinically used. Despite its importance in human physiology and pharmacology, the molecular basis of hENT1-mediated adenosine transport and its inhibition by AdoRIs are limited due to the absence of structural information on hENT1. Here we present crystal structures of hENT1 in complex with two chemically distinct AdoRIs: dilazep and S-(4-Nitrobenzyl)-6-thioinosine (NBMPR). Combined with mutagenesis study, our structural analyses elucidate two distinct inhibitory mechanisms exhibited on hENT1, while giving insight into adenosine recognition and transport. Our studies provide the platform for improved pharmacological intervention of adenosine and nucleoside analog drug transport by hENT1.

A hybrid molecular beam epitaxy approach for atomic-layer controlled growth of high-quality SrTiO3 films with scalable growth rates was developed. The approach uses an effusion cell for Sr, a plasma source for oxygen, and a metal-organic source (titanium tetra isopropoxide) for Ti. SrTiO3 films were investigated as a function of cation flux ratio on (001) SrTiO3 and (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) substrates. Growth conditions for stoichiometric insulating films were identified. Persistent (>180 oscillations) reflection high-energy electron diffraction oscillation characteristic of layer-by-layer growth were observed. The full widths at half maximum of x-ray diffraction rocking curves were similar to those of the substrates, i.e., 34 arc sec on LSAT. The film surfaces were nearly ideal with root mean square surface roughness values of less than 0.1 nm. The relationship between surface reconstructions, growth modes, and stoichiometry is discussed.

The purpose of this study was to investigate interrater and intrarater reliability of the Functional Movement Screen (FMS) with real-time administration with raters of different educational background and experience. The FMS was assessed with real-time administration in healthy injury-free men and women and included a certified FMS rater for comparison with other raters. A relatively new tool, the FMS, was developed to screen 7 individual movement patterns to classify subjects' injury risk. Previous reliability studies have been published with only one investigating intrarater reliability. These studies had limitations in study design and clinical applicability such as the use of only video to rate or the use of raters without comparison to a certified FMS rater. Raters (n = 4) with varying degrees of FMS experience and educational levels underwent a 2-hour FMS training session. Subjects (n = 19) were rated during 2 sessions, 1 week apart, using standard FMS protocol and equipment. Interrater reliability was good for session 1 (intraclass correlation coefficient [ICC] = 0.89) and for session 2 (ICC = 0.87). The individual FMS movements showed hurdle step as the least reliable (ICC = 0.30 for session 1 and 0.35 for session 2), whereas the most reliable was shoulder mobility (ICC = 0.98 for session 1 and 0.96 for session 2). Intrarater reliability was good for all raters (ICC = 0.81-0.91), with similar ICC regardless of education or previous experience with FMS. The results showed that the FMS could be consistently scored by people with varying degrees of experience with the FMS after a 2-hour training session. Intrarater reliability was not increased with FMS certification.