Thermal Stability of Self-Assembled Monolayers of n-Hexanethiol on Au(111)-(1 × 1) and Au(001)-(1 × 1)

Thermal desorption in an ultrahigh vacuum of n-hexanethiol (C6T) self-assembled monolayers (SAMs) prepared from ethanolic solutions on Au(111) and Au(001) unreconstructed surfaces was investigated by X-ray photoelectron spectroscopy. The SAMs desorption was performed from room temperature (RT) to 380 K. We report that the hexanethiolate surface saturation coverage is bigger (∼0.4 ML) for the SAM on Au(001) than on Au(111) (∼0.33 ML). We identified a greater stability for C6T SAMs on Au(001). Large amounts of physisorbed species were found on preferred oriented (111) polycrystalline Au at the low coverage regime at RT, while the SAM on the Au(001) single crystal at this conditions desorbs at a steady pace. At 340 K, both SAMs remain stable at the coverage expected for the lying-down phases that maximizes the van der Waals interactions. We observe that at higher temperatures the carbon alpha-sulfur bond breaks, producing free S on both gold surfaces.Fil: Cristina, Lucila Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; ArgentinaFil: Ruano Sandoval, Gustavo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; ArgentinaFil: Salvarezza, Roberto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Ferron, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Departamento de Materiales; Argentin

Core-level photoemission spectroscopy of nitrogen bonding in GaNxAs1–x alloys

The nitrogen bonding configurations in GaNxAs1–x alloys grown by molecular beam epitaxy with 0.07=0.03, the nitrogen is found to exist in a single bonding configuration – the Ga–N bond; no interstitial nitrogen complexes are present. The amount of nitrogen in the alloys is estimated from the XPS using the N 1s photoelectron and Ga LMM Auger lines and is found to be in agreement with the composition determined by x-ray diffraction

Multiple gene aberrations and breast cancer: lessons from super-responders.

BackgroundThe presence of multiple molecular aberrations in patients with breast cancer may correlate with worse outcomes.Case presentationsWe performed in-depth molecular analysis of patients with estrogen receptor-positive, HER2-negative, hormone therapy-refractory breast cancer, who achieved partial or complete responses when treated with anastrozole and everolimus. Tumors were analyzed using a targeted next generation sequencing (NGS) assay in a Clinical Laboratory Improvement Amendments laboratory. Genomic libraries were captured for 3,230 exons in 182 cancer-related genes plus 37 introns from 14 genes often rearranged in cancer and sequenced to high coverage. Patients received anastrozole (1 g PO daily) and everolimus (5 or 10 mg PO daily). Thirty-two patients with breast cancer were treated on study and 5 (16 %) achieved a partial or complete response. Primary breast tissue was available for NGS testing in three of the responders (partial response with progression free survival of 11 and 14 months, respectively; complete response with progression free survival of 9+ months). The following molecular aberrations were observed: PTEN loss by immunohistochemistry, CCDN1 and FGFR1 amplifications, and PRKDC re-arrangement (NGS) (patient #1); PIK3CA and PIK3R1 mutations, and CCDN1, FGFR1, MYC amplifications (patient #2); TP53 mutation, CCNE1, IRS2 and MCL1 amplifications (patient #3). Some (but not all) of these aberrations converge on the PI3K/AKT/mTOR pathway, perhaps accounting for response.ConclusionsPatients with estrogen receptor-positive breast cancer can achieve significant responses on a combination of anastrozole and everolimus, even in the presence of multiple molecular aberrations. Further study of next generation sequencing-profiled tumors for convergence and resistance pathways is warranted

Signature of Carrier-Induced Ferromagnetism in Ti_{1-x}Co_{x}O_{2-delta}: Exchange Interaction Between High-Spin Co 2+ and the Ti 3d Conduction Band

X-ray photoemission spectroscopy measurements were performed on thin-film samples of rutile Ti_{1-x}Co_{x}O_{2-delta} to reveal the electronic structure. The Co 2p core level spectra indicate that the Co ions take the high-spin Co 2+ configuration, consistent with substitution on the Ti site. The high spin state and the shift due to the exchange splitting of the conduction band suggest strong hybridization between carriers in the Ti 3d t2g band and the t2g states of the high-spin Co 2+. These observations support the argument that room temperature ferromagnetism in Ti_{1-x}Co_{x}O_{2-delta} is intrinsic.Comment: 4 pages, 5 figures. Accepted for publication in Physical Review Letter

Effects of electronic correlation on X-Ray absorption and dichroic spectra at L2,3_{2,3} edge

We present a new theoretical approach to describe X-Ray absorption and Magnetic Circular Dichroism spectra in the presence of e-e correlation. Our approach provides an unified picture to include correlations in both charged and neutral excitations, namely in direct / inversion photoemission where electrons are removed/added, and photo absorption where electrons are promoted from core levels to empty states. We apply this approach to the prototypical case of L$_{2,3}$ edge of 3$d$ transition metals and we show that the inclusion of many body effects in the core level excitations is essential to reproduce, together with satellite structures in core level photoemission, the observed asymmetric line shapes in X-ray absorption and dichroic spectra.Comment: 3 figures, 5 pages, submitted to Phys. Rev.

Standard Flaws for Eddy Current Probe Characterization

Calibration procedures for eddy current inspections often involve the use of artifact standards containing manufactured flaws. The manufactured flaw is assumed to be a good approximation of the type of flaw being sought during the inspection. These manufactured flaws are most often produced by electrical discharge machining (EDM), milling, or the controlled growth of fatigue cracks. With simple amplitude display inspection equipment this type of artifact is usually sufficient, but as more sophisticated inspection equipment is developed some drawbacks to the commonly accepted practice are becoming evident. Instruments that are sensitive to eddy current signal phase as well as amplitude can show considerable differences in phase between a relatively wide EDM notch or milled slot and a real fatigue crack [1]. The use of controlled growth fatigue cracks can also cause problems when forces at the crack’s tip drive the crack faces together, making electrical contact [2], In addition, estimates of crack depth will always be estimates until the crack is broken apart. We describe here a technique for consistently producing well characterized discontinuities in aluminum which are not subject to these problems

Modeling Inspectability for an Automated Eddy Current Measurement System

We have developed an automated eddy current measurement system in our laboratory for quantitative nondestructive evaluation applications. The heart of the measurement system is a precision impedance analyzer capable of measuring impedance or any impedance related quantity over a wide range in frequency (102–108 Hz). Data acquisition, processing, analysis, and display is accomplished with a personal computer. Computer-controlled x-y positioning stages permit measurements to be obtained for either one- or two-dimensional scans of the specimen. In this article we describe the measurement system and give examples of its use to measure flaw signals with a uniform-field eddy current probe [1]

Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square‐Planar Copper(I) Complex

6,6′′‐Bis(2,4,6‐trimethylanilido)terpyridine (H2TpyNMes) was prepared as a rigid, tridentate pincer ligand containing pendent anilines as hydrogen bond donor groups in the secondary coordination sphere. The coordination geometry of (H2TpyNMes)copper(I)‐halide (Cl, Br and I) complexes is dictated by the strength of the NH–halide hydrogen bond. The CuICl and CuIICl complexes are nearly isostructural, the former presenting a highly unusual square‐planar geometry about CuI. The geometric constraints provided by secondary interactions are reminiscent of blue copper proteins where a constrained geometry, or entatic state, allows for extremely rapid CuI/CuII electron‐transfer self‐exchange rates. Cu(H2TpyNMes)Cl shows similar fast electron transfer (≈105 m−1 s−1) which is the same order of magnitude as biological systems.Entatic state: Hydrogen bonds constrain the geometry of CuI and CuII complexes. A highly unusual square‐planar geometry about CuI (see structure) is shown to be nearly isostructural to the CuII core. The minimal reorganization energy between redox states allows for extremely rapid CuI/CuII electron‐transfer self‐exchange rates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134494/1/anie201511527_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134494/2/anie201511527-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134494/3/anie201511527.pd

Eddy-Current and Magnetic Measurements on Case-Hardened Steel

The problem of inspecting case-hardened steel has been of interest to industry for some time. A reliable nondestructive method is sought that will not only enable the depth-of-treatment to be established but will also provide some measure of a component’s bulk material properties and surface condition. While some methods can provide an adequate solution to the problem of measuring case depth, we will show the limitations and pitfalls awaiting the unwary. For example, small variations in heat-treatment conditions can lead to large differences in microstructure, and hence magnetic properties, of a steel. This can be especially true for the near surface layers of a component being treated. These variations in magnetic properties have a strong effect on eddy current and magnetic measurements and can lead to inaccurate results when measuring case depth. In addition, batch variations in material properties can also affect the measurements