Direct observation of LO phonon-plasmon coupled modes in the infrared transmission spectra of n-GaAs and n-InxGa1-xAs epilayers

The infrared transmission spectrum of Si-doped molecular beam epitaxy (MBE)-grown GaAs epilayers, 2-2.5-mum thick, measured in the oblique (Berreman) geometry, revealed distinct minima in p polarization. Given epilayer thickness \u3c reststrahlen wavelength, the minima are identified as the zone-center transverse optic phonon (omega(TO)) and the high-frequency LO phonon-plasmon coupled mode (omega(+)). Analysis of the experimental data yielded free-carrier concentrations ranging from 2.5x10(17) to 1.4x10(18) cm(-3). The same technique with MBE-grown Si-doped In0.53Ga0.47As epilayers (0.5-1 mum thick) yielded omega(+) modes corresponding to free-carrier concentrations of 8.2x10(16)-2.7x10(19) cm(-3). The observations of the transmission minima in the Berreman geometry and their interpretation demonstrate a direct and simple method for deducing free-carrier concentrations over a wide range

Lattice dynamics study of cubic Tb2O3

"This is the peer reviewed version of the following article: Ibáñez, Jordi, Oriol Blázquez, Sergi Hernández, Blas Garrido, Plácida Rodríguez-Hernández, Alfonso Muñoz, Matias Velázquez, Philippe Veber, and Francisco Javier Manjón. 2018. Lattice Dynamics Study of Cubic Tb 2 O 3. Journal of Raman Spectroscopy 49 (12). Wiley: 2021 27. doi:10.1002/jrs.5488, which has been published in final form at https://doi.org/10.1002/jrs.5488. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[EN] We report a joint experimental and theoretical study of the lattice dynamics of cubic Tb2O3. Up to 16 optical Raman-active modes have been observed with polarized and unpolarized Raman scattering measurements on a high-quality Tb2O3 single crystal. The measured wavenumbers have been compared with those of other rare-earth (RE) and related sesquioxides with cubic (C-type or bixbyite) structure. First-principles calculations have allowed us to assign the symmetry of the experimentally observed Raman-active modes. Additional lattice-dynamical calculations on the related cubic RE sesquioxides Dy2O3, Gd2O3, Eu2O3, and Sm2O3 indicate that the phonon wavenumbers of the Raman-active modes in these compounds are monotonically reduced with increasing the lattice parameter along the Dy2O3-Tb2O3-Gd2O3-Eu2O3-Sm2O3 series, thus prompting for a revision of the experimental Raman spectra of some of these compounds (mainly Eu2O3 but also Gd2O3).This study was supported by the Spanish Ministerio de Economía y Competitividad under Projects MAT2015-71070-REDC, MAT2015-71035-R, MAT2016-75586-C4-2-P/3-P, and FIS2017-2017-83295-P.Ibanez, J.; Blazquez, O.; Hernandez, S.; Garrido, B.; Rodríguez-Hernández, P.; Munoz, A.; Velazquez, M.... (2018). Lattice dynamics study of cubic Tb2O3. Journal of Raman Spectroscopy. 49(12):2021-2027. https://doi.org/10.1002/jrs.5488S202120274912Pan, T.-M., Chen, F.-H., & Jung, J.-S. (2010). Structural and electrical characteristics of high-k Tb2O3 and Tb2TiO5 charge trapping layers for nonvolatile memory applications. Journal of Applied Physics, 108(7), 074501. doi:10.1063/1.3490179Kao, C. H., Liu, K. C., Lee, M. H., Cheng, S. N., Huang, C. H., & Lin, W. K. (2012). High dielectric constant terbium oxide (Tb2O3) dielectric deposited on strained-Si:C. Thin Solid Films, 520(8), 3402-3405. doi:10.1016/j.tsf.2011.10.173Gray, N. W., Prestgard, M. C., & Tiwari, A. (2014). Tb2O3 thin films: An alternative candidate for high-k dielectric applications. Applied Physics Letters, 105(22), 222903. doi:10.1063/1.4903072Geppert, I., Eizenberg, M., Bojarczuk, N. A., Edge, L. F., Copel, M., & Guha, S. (2010). Determination of band offsets, chemical bonding, and microstructure of the (TbxSc1−x)2O3/Si system. Journal of Applied Physics, 108(2), 024105. doi:10.1063/1.3427554Belaya, S. V., Bakovets, V. V., Boronin, A. I., Koshcheev, S. V., Lobzareva, M. N., Korolkov, I. V., & Stabnikov, P. A. (2014). Terbium oxide films grown by chemical vapor deposition from terbium(III) dipivaloylmethanate. Inorganic Materials, 50(4), 379-386. doi:10.1134/s0020168514040037Bakovets, V. V., Belaya, S. V., Lobzareva, M. N., & Maksimovskii, E. A. (2014). Kinetics of terbium oxide film growth from Tb(dpm)3 vapor. Inorganic Materials, 50(6), 576-581. doi:10.1134/s0020168514060016Veber, P., Velázquez, M., Gadret, G., Rytz, D., Peltz, M., & Decourt, R. (2015). Flux growth at 1230 °C of cubic Tb2O3single crystals and characterization of their optical and magnetic properties. CrystEngComm, 17(3), 492-497. doi:10.1039/c4ce02006eAbrashev, M. V., Todorov, N. D., & Geshev, J. (2014). Raman spectra of R2O3 (R—rare earth) sesquioxides with C-type bixbyite crystal structure: A comparative study. Journal of Applied Physics, 116(10), 103508. doi:10.1063/1.4894775Urban, M. W., & Cornilsen, B. C. (1987). Bonding anomalies in the rare earth sesquioxides. Journal of Physics and Chemistry of Solids, 48(5), 475-479. doi:10.1016/0022-3697(87)90108-9Hohenberg, P., & Kohn, W. (1964). Inhomogeneous Electron Gas. Physical Review, 136(3B), B864-B871. doi:10.1103/physrev.136.b864Kresse, G., & Furthmüller, J. (1996). Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Computational Materials Science, 6(1), 15-50. doi:10.1016/0927-0256(96)00008-0Blöchl, P. E. (1994). Projector augmented-wave method. Physical Review B, 50(24), 17953-17979. doi:10.1103/physrevb.50.17953Kresse, G., & Joubert, D. (1999). From ultrasoft pseudopotentials to the projector augmented-wave method. Physical Review B, 59(3), 1758-1775. doi:10.1103/physrevb.59.1758Perdew, J. P., Burke, K., & Ernzerhof, M. (1996). Generalized Gradient Approximation Made Simple. Physical Review Letters, 77(18), 3865-3868. doi:10.1103/physrevlett.77.3865Perdew, J. P., Ruzsinszky, A., Csonka, G. I., Vydrov, O. A., Scuseria, G. E., Constantin, L. A., … Burke, K. (2008). Restoring the Density-Gradient Expansion for Exchange in Solids and Surfaces. Physical Review Letters, 100(13). doi:10.1103/physrevlett.100.136406Monkhorst, H. J., & Pack, J. D. (1976). Special points for Brillouin-zone integrations. Physical Review B, 13(12), 5188-5192. doi:10.1103/physrevb.13.5188Garcia-Domene, B., Ortiz, H. M., Gomis, O., Sans, J. A., Manjón, F. J., Muñoz, A., … Tyagi, A. K. (2012). High-pressure lattice dynamical study of bulk and nanocrystalline In2O3. Journal of Applied Physics, 112(12), 123511. doi:10.1063/1.4769747Gomis, O., Santamaría-Pérez, D., Ruiz-Fuertes, J., Sans, J. A., Vilaplana, R., Ortiz, H. M., … Mollar, M. (2014). High-pressure structural and elastic properties of Tl2O3. Journal of Applied Physics, 116(13), 133521. doi:10.1063/1.4897241K.Parlinski Phonon code seehttp://www.computingformaterials.com/.Todorov, N. D., Abrashev, M. V., Marinova, V., Kadiyski, M., Dimowa, L., & Faulques, E. (2013). Raman spectroscopy and lattice dynamical calculations of Sc2O3single crystals. Physical Review B, 87(10). doi:10.1103/physrevb.87.104301White, W. B., & Keramidas, V. G. (1972). Vibrational spectra of oxides with the C-type rare earth oxide structure. Spectrochimica Acta Part A: Molecular Spectroscopy, 28(3), 501-509. doi:10.1016/0584-8539(72)80237-xKranert, C., Schmidt-Grund, R., & Grundmann, M. (2014). Raman active phonon modes of cubic In2O3. physica status solidi (RRL) - Rapid Research Letters, 8(6), 554-559. doi:10.1002/pssr.201409004Ubaldini, A., & Carnasciali, M. M. (2008). Raman characterisation of powder of cubic RE2O3 (RE=Nd, Gd, Dy, Tm, and Lu), Sc2O3 and Y2O3. Journal of Alloys and Compounds, 454(1-2), 374-378. doi:10.1016/j.jallcom.2006.12.067Mochizuki, S., Fujishiro, F., & Ishiwata, K. (2005). Photo-induced valence-number changes and defects in Eu2O3fine particle films. Journal of Physics: Conference Series, 21, 189-194. doi:10.1088/1742-6596/21/1/03

Automated radiofrequency-based US measurement of common carotid intima-media thickness in RA patients treated with synthetic vs synthetic and biologic DMARDs

Objective. To compare the carotid intima-media thickness (IMT) assessed with automated radiofrequency-based US in RA patients treated with synthetic vs synthetic and biologic DMARDs and controls. Methods. Ninety-four RA patients and 94 sex-and age-matched controls were prospectively recruited at seven centres. Cardiovascular (CV) risk factors and co-morbidities, RA characteristics and therapy were recorded. Common carotid artery (CCA)-IMT was assessed in RA patients and controls with automated radiofrequency-based US by the same investigator at each centre. Results. Forty-five (47.9%) RA patients had been treated with synthetic DMARDs and 49 (52.1%) with synthetic and biologic DMARDs. There were no significant differences between the RA patients and controls in demographics, CV co-morbidities and CV disease. There were significantly more smokers among RA patients treated with synthetic and biologic DMARDs (P = 0.036). Disease duration and duration of CS and synthetic DMARD therapy was significantly longer in RA patients treated with synthetic and biologic DMARDs (P<0.0005). The mean CCA-IMT was significantly greater in RA patients treated only with synthetic DMARDs than in controls [591.4 (98.6) vs 562.1 (85.8); P = 0.035] and in RA patients treated with synthetic and biologic DMARDs [591.4 (98.6) vs 558.8 (95.3); P = 0.040). There was no significant difference between the mean CCA-IMT in RA patients treated with synthetic and biologic DMARDs and controls (P = 0.997). Conclusion. Our results suggest that radiofrequency-based measurement of CCA-IMT can discriminate between RA patients treated with synthetic DMARDs vs RA patients treated with synthetic and biologic DMARDs

Instrumentation for Examining Microbial Response to Changes In Environmental Pressures

The Automated Adaptive Directed Evolution Chamber (AADEC) is a device that allows operators to generate a micro-scale analog of real world systems that can be used to model the local-scale effects of climate change on microbial ecosystems. The AADEC uses an artificial environment to expose cultures of micro-organisms to environmental pressures, such as UV-C radiation, chemical toxins, and temperature. The AADEC autonomously exposes micro-organisms to selection pressures. This improves upon standard manual laboratory techniques: the process can take place over a longer period of time, involve more stressors, implement real-time adjustments based on the state of the population, and minimize the risk of contamination. We currently use UV-C radiation as the main selection pressure, UV-C is well studied both for its cell and DNA damaging effects as a type of selection pressure and for its related effectiveness as a mutagen; having these functions united makes it a good choice for a proof of concept. The AADEC roadmap includes expansion to different selection pressures, including heavy metal toxicity, temperature, and other forms of radiation.The AADEC uses closed-loop control to feedback the current state of the culture to the AADEC controller that modifies selection pressure intensity during experimentation, in this case culture density and growth rate. Culture density and growth rate are determined by measuring the optical density of the culture using 600 nm light. An array of 600 nm LEDs illuminate the culture and photodiodes are used to measure the shadow on the opposite side of the chamber.Previous experiments showed that we can produce a million fold increase to UV-C radiation over seven iterations. The most recent implements a microfluidic system that can expose cultures to multiple different selection pressures, perform non-survival based selection, and autonomously perform hundreds of exposure cycles. A scalable pump system gives the ability to pump in various different growth media to individual cultures and introduce chemical toxins during experimentation; AADEC can perform freeze and thaw cycles. We improved our baseline characterization by building a custom UV-C exposure hood, a shutter operates on a preset timer allowing the user to set exposure intensity consistently for multiple iterations

Design and rationale of a multicentre, randomised, double-blind, placebo-controlled clinical trial to evaluate the effect of vitamin D on ventricular remodelling in patients with anterior myocardial infarction: the VITamin D in Acute Myocardial Infarction (VITDAMI) trial

Introduction:Decreased plasma vitamin D (VD) levels are linked to cardiovascular damage. However, clinical trials have not demonstrated a benefit of VD supplements on left ventricular (LV) remodelling. Anterior ST-elevation acute myocardial infarction (STEMI) is the best human model to study the effect of treatments on LV remodelling. We present a proof-of-concept study that aims to investigate whether VD improves LV remodelling in patients with anterior STEMI. Methods and analysis:The VITamin D in Acute Myocardial Infarction (VITDAMI) trial is a multicentre, randomised, double-blind, placebo-controlled trial. 144 patients with anterior STEMI will be assigned to receive calcifediol 0.266 mg capsules (Hidroferol SGC)/15 days or placebo on a 2:1 basis during 12 months. Primary objective:to evaluate the effect of calcifediol on LV remodelling defined as an increase in LV end-diastolic volume >= 10\% (MRI). Secondary objectives:change in LV end-diastolic and end-systolic volumes, ejection fraction, LV mass, diastolic function, sphericity index and size of fibrotic area; endothelial function; plasma levels of aminoterminal fragment of B-type natriuretic peptide, galectin-3 and monocyte chemoattractant protein-1; levels of calcidiol (VD metabolite) and other components of mineral metabolism (fibroblast growth factor-23 (FGF-23), the soluble form of its receptor klotho, parathormone and phosphate). Differences in the effect of VD will be investigated according to the plasma levels of FGF-23 and klotho. Treatment safety and tolerability will be assessed. This is the first study to evaluate the effect of VD on cardiac remodelling in patients with STEMI. Ethics and dissemination: This trial has been approved by the corresponding Institutional Review Board (IRB) and National Competent Authority (Agencia Espanola de Medicamentos y Productos Sanitarios (AEMPS)). It will be conducted in accordance with good clinical practice (International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use-Good Clinical Practice (ICH-GCP)) requirements, ethical principles of the Declaration of Helsinki and national laws. The results will be submitted to indexed medical journals and national and international meetings.The VITDAMI trial is an investigator initiated study, sponsored by the Instituto de Investigacion Sanitaria Fundacion Jimenez Diaz (IIS-FJD). Funding has been obtained from Fondo de Investigaciones Sanitarias (PI14/01567; http://www.isciii.es/) and Spanish Society of Cardiology (http://secardiologia.es/). In addition, the study medication has been provided freely by the pharmaceutical Company FAES FARMA S.A. (Leioa, Vizcaya, Spain; http://faesfarma.com/). This company was the only funder who collaborated in study design (IG-H).S

Epidemic Clostridium difficile Ribotype 027 in Chile

The increased severity of Clostridium difficile infection is primarily attributed to the appearance of an epidemic strain characterized as PCR ribotype 027. The only report that identified epidemic C. difficile ribotype 027 in an American country outside of North America comes from Costa Rica, raising the possibility that strains 027 might also be present in other countries of Latin America. Several studies between 2001 and 2009 have been conducted in South American countries to detect the incidence of C. difficile infection in hospitalized patients, but they did not identify which C. difficile strains were causing these infections

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

Brain health in diverse settings : How age, demographics and cognition shape brain function

Peer reviewe

A Missense Variant in PTPN22 is a Risk Factor for Drug-induced Liver Injury

Background & Aims We performed genetic analyses of a multiethnic cohort of patients with idiosyncratic drug-induced liver injury (DILI) to identify variants associated with susceptibility. Methods We performed a genome-wide association study of 2048 individuals with DILI (cases) and 12,429 individuals without (controls). Our analysis included subjects of European (1806 cases and 10,397 controls), African American (133 cases and 1,314 controls), and Hispanic (109 cases and 718 controls) ancestry. We analyzed DNA from 113 Icelandic cases and 239,304 controls to validate our findings. Results We associated idiosyncratic DILI with rs2476601, a nonsynonymous polymorphism that encodes a substitution of tryptophan with arginine in the protein tyrosine phosphatase, nonreceptor type 22 gene (PTPN22) (odds ratio [OR] 1.44; 95% confidence interval [CI] 1.28–1.62; P = 1.2 × 10–9 and replicated the finding in the validation set (OR 1.48; 95% CI 1.09–1.99; P = .01). The minor allele frequency showed the same effect size (OR > 1) among ethnic groups. The strongest association was with amoxicillin and clavulanate-associated DILI in persons of European ancestry (OR 1.62; 95% CI 1.32–1.98; P = 4.0 × 10–6; allele frequency = 13.3%), but the polymorphism was associated with DILI of other causes (OR 1.37; 95% CI 1.21–1.56; P = 1.5 × 10–6; allele frequency = 11.5%). Among amoxicillin- and clavulanate-associated cases of European ancestry, rs2476601 doubled the risk for DILI among those with the HLA risk alleles A*02:01 and DRB1*15:01. Conclusions In a genome-wide association study, we identified rs2476601 in PTPN22 as a non-HLA variant that associates with risk of liver injury caused by multiple drugs and validated our finding in a separate cohort. This variant has been associated with increased risk of autoimmune diseases, providing support for the concept that alterations in immune regulation contribute to idiosyncratic DILI