Optical properties of Mn-doped GaN

Molecular beam epitaxy-grown GaN with different Mn concentrations (5-23×1019 cm-3) and codoped with Si were investigated by cathodoluminescence (CL) spectroscopy and optical transmission measurements. In the GaN:Mn, an intense absorption peak at 1.414 +/- 0.002 eV was observed. This peak was attributed to an internal 5T 2→ 5E transition of the deep neutral Mn3+ state since its intensity scaled with the Mn3+ concentration. The CL measurements showed that Mn-doping concentrations around 1020 cm -3 had three effects on the emission spectrum: (i) the donor bound exciton at 3.460 eV was reduced by more than one order of magnitude, (ii) the donor-acceptor-pair band at 3.27 eV was completely quenched and (iii) the yellow luminescence centered at 2.2 eV was the strongly decreased. The latter two effects were attributed to a reduced concentration of VGa. In the infrared spectral range, three broad, Mn-doping related CL emission bands centered at 1.01 ± 0.02 eV, 1.09 ± 0.02 eV and 1.25 ± 0.03 eV were observed. These bands might be related to deep donor complexes, which are generated as a result of the heavy Mn-doping, rather than internal transitions at the Mn atom

Nodal quasiparticle meltdown in ultra-high resolution pump-probe angle-resolved photoemission

High-$T_c$ cuprate superconductors are characterized by a strong momentum-dependent anisotropy between the low energy excitations along the Brillouin zone diagonal (nodal direction) and those along the Brillouin zone face (antinodal direction). Most obvious is the d-wave superconducting gap, with the largest magnitude found in the antinodal direction and no gap in the nodal direction. Additionally, while antinodal quasiparticle excitations appear only below $T_c$, superconductivity is thought to be indifferent to nodal excitations as they are regarded robust and insensitive to $T_c$. Here we reveal an unexpected tie between nodal quasiparticles and superconductivity using high resolution time- and angle-resolved photoemission on optimally doped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$. We observe a suppression of the nodal quasiparticle spectral weight following pump laser excitation and measure its recovery dynamics. This suppression is dramatically enhanced in the superconducting state. These results reduce the nodal-antinodal dichotomy and challenge the conventional view of nodal excitation neutrality in superconductivity.Comment: 7 pages, 3 figure. To be published in Nature Physic

Dynamic and volumetric variables reliably predict fluid responsiveness in a porcine model with pleural effusion

Background: The ability of stroke volume variation (SVV), pulse pressure variation (PPV) and global end-diastolic volume (GEDV) for prediction of fluid responsiveness in presence of pleural effusion is unknown. The aim of the present study was to challenge the ability of SVV, PPV and GEDV to predict fluid responsiveness in a porcine model with pleural effusions. Methods: Pigs were studied at baseline and after fluid loading with 8 ml kg−1 6% hydroxyethyl starch. After withdrawal of 8 ml kg−1 blood and induction of pleural effusion up to 50 ml kg−1 on either side, measurements at baseline and after fluid loading were repeated. Cardiac output, stroke volume, central venous pressure (CVP) and pulmonary occlusion pressure (PAOP) were obtained by pulmonary thermodilution, whereas GEDV was determined by transpulmonary thermodilution. SVV and PPV were monitored continuously by pulse contour analysis. Results: Pleural effusion was associated with significant changes in lung compliance, peak airway pressure and stroke volume in both responders and non-responders. At baseline, SVV, PPV and GEDV reliably predicted fluid responsiveness (area under the curve 0.85 (p<0.001), 0.88 (p<0.001), 0.77 (p = 0.007). After induction of pleural effusion the ability of SVV, PPV and GEDV to predict fluid responsiveness was well preserved and also PAOP was predictive. Threshold values for SVV and PPV increased in presence of pleural effusion. Conclusions: In this porcine model, bilateral pleural effusion did not affect the ability of SVV, PPV and GEDV to predict fluid responsiveness

Learning and Long-Term Retention of Large-Scale Artificial Languages

Recovering discrete words from continuous speech is one of the first challenges facing language learners. Infants and adults can make use of the statistical structure of utterances to learn the forms of words from unsegmented input, suggesting that this ability may be useful for bootstrapping language-specific cues to segmentation. It is unknown, however, whether performance shown in small-scale laboratory demonstrations of “statistical learning” can scale up to allow learning of the lexicons of natural languages, which are orders of magnitude larger. Artificial language experiments with adults can be used to test whether the mechanisms of statistical learning are in principle scalable to larger lexicons. We report data from a large-scale learning experiment that demonstrates that adults can learn words from unsegmented input in much larger languages than previously documented and that they retain the words they learn for years. These results suggest that statistical word segmentation could be scalable to the challenges of lexical acquisition in natural language learning.National Science Foundation (U.S.) (NSF DDRIG #0746251

Perspective from a Younger Generation -- The Astro-Spectroscopy of Gisbert Winnewisser

Gisbert Winnewisser's astronomical career was practically coextensive with the whole development of molecular radio astronomy. Here I would like to pick out a few of his many contributions, which I, personally, find particularly interesting and put them in the context of newer results.Comment: 14 pages. (Co)authored by members of the MPIfR (Sub)millimeter Astronomy Group. To appear in the Proceedings of the 4th Cologne-Bonn-Zermatt-Symposium "The Dense Interstellar Medium in Galaxies" eds. S. Pfalzner, C. Kramer, C. Straubmeier, & A. Heithausen (Springer: Berlin

An exceptionally well-preserved skeleton of Palaeothentes from the Early Miocene of Patagonia, Argentina: new insights into the anatomy of extinct paucituberculatan marsupials

International audienc

Cost of poor adherence to anti-hypertensive therapy in five European countries

The financial burden for EU health systems associated with cardiovascular disease (CV) has been estimated to be nearly €110 billion in 2006, corresponding to 10 % of total healthcare expenditure across EU or a mean €223 annual cost per capita. The main purpose of this study is to estimate the costs related to hypertension and the economic impact of increasing adherence to anti-hypertensive therapy in five European countries (Italy, Germany, France, Spain and England). A probabilistic prevalence-based decision tree model was developed to estimate the direct costs of CV related to hypertension (CV defined as: stroke, heart attack, heart failure) in five European countries. Our model considered adherence to hypertension treatment as a main driver of blood pressure (BP) control (BP < 140/90 mmHg). Relative risk of CV, based on controlled or uncontrolled BP group, was estimated from the Framingham Heart Study and national review data. Prevalence and cost data were estimated from national literature reviews. A national payer (NP) perspective for 10 years was considered. Probabilistic sensitivity analysis was performed in order to evaluate uncertainty around the results (given as 95 % confidence intervals). The model estimated a total of 8.6 million (1.4 in Italy, 3.3 in Germany, 1.2 in Spain, 1.8 in France and 0.9 in England) CV events related to hypertension over the 10-year time horizon. Increasing the adherence rate to anti-hypertensive therapy to 70 % (baseline value is different for each country) would lead to 82,235 fewer CV events (24,058 in Italy, 7,870 in Germany, 18,870 in Spain, 24,855 in France and 6,553 in England). From the NP perspective, the direct cost associated with hypertension was estimated to be €51.3 billion (8.1 in Italy, 17.1 in Germany, 12.2 in Spain, 8.8 in France and 5.0 in England). Increasing adherence to anti-hypertensive therapy to 70 % would save a total of €332 million (CI 95 %: €319-346 million) from the NPs perspective. This study is the first attempt to estimate the economic impact of non-adherence amongst patients with diagnosed hypertension in Europe, using data from five European countries (Italy, France, Germany, Spain and England). © 2014 Springer-Verlag Berlin Heidelberg

Multifunctional semi-interpenetrating polymer network-nanoencapsulated cathode materials for high-performance lithium-ion batteries

As a promising power source to boost up advent of next-generation ubiquitous era, high-energy density lithium-ion batteries with reliable electrochemical properties are urgently requested. Development of the advanced lithium ion-batteries, however, is staggering with thorny problems of performance deterioration and safety failures. This formidable challenge is highly concerned with electrochemical/thermal instability at electrode material-liquid electrolyte interface, in addition to structural/chemical deficiency of major cell components. Herein, as a new concept of surface engineering to address the abovementioned interfacial issue, multifunctional conformal nanoencapsulating layer based on semi-interpenetrating polymer network (semi-IPN) is presented. This unusual semi-IPN nanoencapsulating layer is composed of thermally-cured polyimide (PI) and polyvinyl pyrrolidone (PVP) bearing Lewis basic site. Owing to the combined effects of morphological uniqueness and chemical functionality (scavenging hydrofluoric acid that poses as a critical threat to trigger unwanted side reactions), the PI/PVP semi-IPN nanoencapsulated-cathode materials enable significant improvement in electrochemical performance and thermal stability of lithium-ion batteries.open

Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress

In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse

A non-randomized comparison of gemcitabine-based chemoradiation with or without induction chemotherapy for locally advanced squamous cell carcinoma of the head and neck

<p>Abstract</p> <p>Background</p> <p>Concomitant chemotherapy and radiotherapy (chemoradiation; CRT) is the standard treatment for locoregionally advanced squamous cell carcinoma of the head and neck (LA-SCCHN). CRT improves local control and overall survival (OS) when compared to radiotherapy (RT) alone. Induction chemotherapy (IC) reduces the risk of distant metastases (DM) and improves OS by 5% with the use of cisplatin/infusional 5 fluorouracil (PF) in meta-analysis. Adding a taxane to PF in the IC regimen confers a better outcome. Sequential treatment (ST) of IC followed by CRT is therefore under active investigation in multiple phase III trials.</p> <p>Methods</p> <p>We compared the outcome of two cohorts of patients (pts) with LA-SCCHN treated at our institution with CRT (n = 27) or ST (n = 31), respectively. CRT consisted of GEM 100 mg/m²weekly + conventional RT (70 Gy); ST consisted of the same CRT preceded by platinum-based IC.</p> <p>Results</p> <p>Response to IC: complete 8 (26%), partial 20 (65%), stable 1, progressive 1, not evaluable 1. Median follow up of the surviving pts: for CRT 73 months, for ST 51 months. Median time to distant metastasis (TDM) was for CRT 23.6 months, for ST not reached. Median OS was for CRT 20.2 months, for ST 40.2 months. Cox regression analysis, taking into account age, T and N stage and tumor site, showed a hazard ratio with ST of 1.190 for time to locoregional failure (p = 0.712), 0.162 for TDM (p = 0.002), and 0.441 for overall survival (OS) (p = 0.026).</p> <p>Conclusion</p> <p>TDM and OS were found significantly longer in the ST cohort without a reduced locoregional control. Notwithstanding the limitations of a non-randomized single-center comparison, the results are in line with very preliminary data of randomized comparisons suggesting an improved outcome with ST.</p